electrical resistivity as an approach to evaluating brine

Western Michigan University Western Michigan University

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Master's Theses Graduate College

6-1988

Electrical Resistivity as an Approach to Evaluating Brine Electrical Resistivity as an Approach to Evaluating Brine

Contamination of Groundwater in the Walker Oil Field, Ottawa Contamination of Groundwater in the Walker Oil Field, Ottawa

County, Michigan County, Michigan

Janet A. Koehler

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ELECTRICAL RESISTIVITY AS AN APPROACH TO EVALUATING BRINE CONTAMINATION OF GROUNDWATER IN THE WALKER

OIL FIELD, OTTAWA COUNTY, MICHIGAN

by

Janet A. Koehler

A Thesis Submitted to the

Faculty of The Graduate College in partial fulfillment of the

requirements for the Degree of Master of Science

Department of Geology

Western Michigan University Kalamazoo, Michigan

June 1988

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

ELECTRICAL RESISTIVITY AS AN APPROACH TO EVALUATING BRINE CONTAMINATION OF GROUNDWATER IN THE WALKER

OIL FIELD, OTTAWA COUNTY, MICHIGAN

Janet A. Koehler, M.S.

Western Michigan University, 1988

Surface electrical resistivity successfully defined brine

contamination within a glacial drift aquifer in western Michigan.

The study site is in a residential area of eastern Ottawa County,

in the Walker Oil Field. A Schluraberger array with a maximum

current electrode separation (AB/2) of 316 meters (1037 feet) was

used. It was possible to detect geoelectric layers to about 30

meters (100 feet) below ground level, with the maximum current

penetration of about 1/10 (AB/2). On occasion, thick surficial

clay precluded detecting deeper geoelectric layers. Through use

of the INVERS computer program, fifty vertical electrical

soundings were interpreted and correlated with geological,

geophysical and water quality data. Low resistivity zones were

identified on several geoelectric sections within the glacial sand

aquifers adjacent to water wells in which relatively high levels

of chloride and specific conductance had been detected. The

conclusion is that these low resistivity layers represent

groundwater contamination zones.


ACKNOWLEDGMENTS

I would like to extend a special thank you to Dr. Richard

Passero for his continual support and guidance during the course

of this study, and throughout ray academic career at Western

Michigan University. Also, I ara greatly indebted to Dr. William

Sauck whose geophysical expertise was invaluable to this study.

As my thesis committee members, I am grateful to Dr. W. Thomas

Straw and Dr. Gerry Clarkson for their constructive criticism of

ray work. I would like to thank Mr. David Westjohn for his

enthusiasm and encouragement, and for having critiqued ray report.

Special thanks is due to all those who helped me with my

field work, especially my good friends, Kent Meisel, Terry Wagner,

Kayleen Jalkut and Lula Palmer. Also I must thank Chuck Graff

and Jean Talanda for their drafting skills and their comradery. I

am grateful to the U.S.E.P.A. for allowing me to work under the

Walker Oil Field study.

Most of all I would like to thank my parents, Dr. James

Koehler and Genevieve Koehler, for their continual encouragement

and their love.

Janet A. Koehler

11


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Uni

International300 N. Zeeb Road Ann Arbor, Ml 48106


O rder N um ber 1334190

Electrical resistivity as an approach to evaluating brine contam ination o f groundwater in the Walker Oil Field, O ttawa County, M ichigan

Koehler, Janet A., M.S.

Western Michigan University, 1988

Copyright ©1988 by Koehler, Janet A. All rights reserved.

U MI300 N. Zeeb Rd.Ann Arbor, MI 48106


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Copyright by Janet A. Koehler

1988


TABLE OF CONTENTS

ACKNOWLEDGMENTS................................................... ii

LIST OF TABLES....................................................vi

LIST OF FIGURES..................................................vii

LIST OF PLATES.................................................... ix

INTRODUCTION....................................................... 1

HISTORY OF THE WALKER OIL FIELD................................... 4

REGIONAL SETTING.................................................. 10

Surficial Geology............... 10

Subsurface Geology............................................. 10

Surface Hydrology..............................................12

Hydrogeology................................................... 12

Groundwater Quality............................................14

STUDY AREA........................................................ 11

General Description............................................16

Surficial Geology..............................................16

Subsurface Geology.............................................18

Surface Hydrology..............................................22

Hydrogeology................................................... 22

Groundwater Quality............................................28

REVIEW OF ELECTRICAL RESISTIVITY USEDIN HYDROGEOLOGICAL PROBLEMS...................................... 36

PREVIOUS WORK IN THE WALKER OIL FIELD AREA.......................38

iii


TABLE OF CONTENTS — Continued

ELECTRICAL RESISTIVITY

Definition..................................................... 39

Uses........................................................... 39

Factors Governing Resistivity of Rock Materials............. 40

Types of Electrode Configurations and Exploration Methods..44

Theory....................................................... 48

Field Methods................................................50

Data Reduction...............................................56

First Stage...............................................57

Second Stage..............................................60

Third Stage...............................................63

Interpretation of Field Data................................ 65

Geoelectric Section A .................................... 68

Geoelectric Section D.................................... 72

Geoelectric Section E.................................... 74

Longitudinal Conductance Map................. 77

Laboratory Procedures....................................... 79

CONCLUSIONS AND RECOMMENDATIONS.................................. 81

APPENDICES........................................................ 85

A. Equipment..................................................86

B. Soil Boring Data and Labpratory Results................... 90

iv


TABLE OF CONTENTS — Continued

C. Apparent Resistivity Data..................................95

D. Archie's Law Calculations.................................134

E. Geoelectric Sections B, C, F, G, H, and 1................ 1)6

BIBLIOGRAPHY..................................................... 143

v


LIST OF TABLES

1. Oil Well Record Sunmary for the Study Area................... 6

2. Brine Production and Disposal RecordSummary for the Study Area.................................... 8

3. Water Quality Data and Domestic Welland Soil Boring Depth........................................ 31

4. Electrical Resistivity Values of GeologicalMaterials (after Telford).................................... 43

vi


LIST OF FIGURES

1. Location Map Showing Site Area Within TallmadgeTownship, Ottawa County, Michigan............................2

2. Detailed Map of the Study Area Showing Domestic Welland Cross Section Locations.................................. 3

3. Map Showing Location and Approximate Size of the Walker Oil Field (Michigan Department of Natural Resources, 1981)..............................................5

4. Site Map Showing Permit Numbers of Both Activeand Abandoned Oil Wells...................................... 7

5. Map Showing the Approximate Location of Ottawa County Relative to the Glacial Systems in Lower Michiganas Mapped by Leverett and Taylor, 1915......................11

6. Glacial Landforms in the Study Area (After Ten Brink,1975)........................................................ 17

7. Site Map Showing Drift Thickness Based on Oil WellRecord Data.................................................. 19

8. Site Map Showing Bedrock (Michigan Formation)Surface Based on Oil Well Record Data.......................21

9. Geological Cross Section Along the South Side of Leonard Street, Tallmadge Township, Ottawa County.................. 24

10. Geological Cross Section Along Private Drive Northof Leonard Street, Tallmadge Township, Ottawa.............. 25

11. Geological Cross Section Along 14th Street, Tallmadge Township, Ottawa.............................................26

12. Geological Cross Section Along Leonard Street Extension, Tallmadge Township, Ottawa.................................. 27

13. Groundwater Flow Direction Based on PotentiometricSurface of the Study Area...................................29

14. Isoconcentration Map of Chloride (mg/L) of DomesticWell Water (values collected by Wagner, 1988)...............32

vii


LIST OF FIGURES — Continued

15. Map of Specific Conductance (umhos/cra) of DomesticWell Water (values collected by Wagner, 1988).............. 33

16. Schlumberger Electrode Arrangement.......................... 45

17. Uniform Three Dimensional Current Flow...................... 45

18. Distortion of Current Flow Lines When Crossing theBoundary Between Media of Differing Resistivity............45

19. Changes in Layer Thickness (h), and Electrode SeparationInfluence Current Flow Direction............................ 49

20. Map Showing the Locations of VESand Geoelectric Sections.................................... 51

21. Sample of Field Data......................................... 52

22. Hypothetical Schlumberger Field Curve ShowingCurve Segment Displacement.................................. 55

23. Sample of Study Area Field Curves............................58

24. Four Basic Relationships Between Resistivityand Thickness in a Three-Layered Subsurface................ 60

25. Map of Longitudinal Conductance (mhos)...................... 64

26. Arrangement of Sheet Electrodes Used in LaboratoryAnalysis of Soil Samples.................................... 79

27. Sketch of IC-69 Earth Resistivity Meter..................... 87

viii


LIST OF ELATES

1. Geoelectric Section A

2. Geoelectric Section D

3. Geoelectric Section E


INTRODUCTION

The purpose of this investigation was to determine the

effectiveness of surface electrical resistivity as a means of

detecting groundwater contamination from oil field brines in the

Walker Oil Field. Electrical methods have been utilized

frequently in defining subsurface geology and hydrology. Surface

electrical resistivity has not generally been employed in

populated areas where cultural phenomena limit the application of

resistivity surveys.

The area investigated is located within the northern-most

portion of the Walker Oil Field in Tallmadge Township, Ottawa,

County Michigan (Figure 1). More specifically, it occupies the

southwestern quarter of section 14 and the southeastern quarter of

section 15 of Township 7 North, Range 3 West. The site is bounded

by Sand Creek and its tributary to the north and west, 14th Street

to the east, and the southern border of section 14 and 15 to the

south (Figure 2).

1


2

TallmadgeTownship

s tudy site

OttawaCounty

-t— ----10 2 miles

Figure 1. Location Map Showing Site Area Within Tallmadge Township, Ottawa County.


3

1 8 0 S DOMEST I C WELL L O C A T I O N

SOIL B O U I N O L O CA T I O N

Figure 2. Detailed Map of the Study Area Showing Domestic Well and Cross Section Locations.


HISTORY OF THE WALKER OIL FIELD

The Walker Oil Field includes portions of Kent and Ottawa

Counties. The field, discovered in 1938, encompasses 8560 acres

(Figure 3). More than 780 wells drilled in the Walker Oil Field

produce gas, oil and brine. Production peaked by 1940, and

cumulative production reached more than 4,000,000 barrels of oil

(Michigan Department of Natural Resources, 1981). The Walker Oil

Field was the most active Michigan oil field that year (Newcombe,

1940). Oil production has steadily decreased since the early 1940's.

Oil is produced from the Traverse Limestone in the upper part

of the Devonian Traverse Group. Within the study area the Traverse

Limestone ranges from 2 to 13 meters (8 to 42 feet) in thickness,

and the pay zone ranges from 1 to 6 meters (3 to 19 feet) (Table 1).

Ten oil wells were drilled in the study area. Four of these oil

wells currently produce oil and brine from depths of 566 to 625

meters (1858 to 2050 feet) below ground level (Figure 4). Six oil

wells have been plugged and abandoned. Most of the wells in this

portion of the Walker Oil Field have produced for 26 years.

Since the 1940's a small portion of Michigan oil field brine has

been used for road maintenance. The majority of this brine was

disposed of to surface pits. In the study area pit disposal was

used for nearly 35 years from 1940 through 1975. Pits consisted of

shallow unlined excavations in the existing soils located near pump

jacks and tanks. Surface application of oil field brine is a

possible cause of the degradation of groundwater supplies.

4


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Figure 3. Map Showing Location and Approximate Size of the Walker Oil Field (Michigan Department of Natural Resources, 1981).

gas field

oil field

oil and gas fields

112 miles

i

Table 1

Oil Well Record Summary for the Study Area*

EerraitNumber Drift MI MA CLD ELS ANT TRV

TRVLS PAY

TotalDepth

* 7318 118 57 249 681 538 149 66 10 8 1857.5

* 7695 94 126 215 690 535 142 73 14 8 1875

* 7824 125 55 275 682 525 153 59 8 6 1874

7887 100 75 240 605 510 174 60 14 7 1864

8424 132 55 273 698 514 148 69 42 6 1889

9385 190 0 240 741 534 115 55 8 3 1875

9851 120 35 310 682 508 163 187 34 11 2050

*13156 155 35 265 683 537 157 61 11 4 1888.5

13447 163 17 277 703 540 119 73 25 17 1892

21965 121 69 250 702 534 146 72 23 19 1894

* formation thickness and depth in feet

* active oil wells


7

P R O D U C I N G O i l W i l l

A B A N D O N E D O i l W f l l

H O L D I N G T A N K S

O i l W i l l P E R M I T NO.

2 1 9 8 5

7 8 9 5

•̂ 96 5 1

4 4 7

8 4 2 4

Figure 4. Site Map Showing Permit Numbers of Both Active and Abandoned Oil Wells.


Table 2

Brine Production and Disposal Record Summary for the Study Area (1949-81)

PermitNumber

ProducedOil

ProducedBrine

Brine To Brine To Pits Injection Wells

* 7318 9465.4 5905.8 2555.0 3350.8

* 7695 14099.9 6168.6 5383.8 784.8

* 7824 - no production records -

7887 22447.5 5110.0 3650.0 1460.0

8424 365.0 273.8 273.8 0.0

9385 2555.0 547.5 547.5 0.0

9851 1277.5 1825.0 1825.0 0.0

*13156 10541.2 2518.6 1733.8 784.8

13447 2555.0 547.5 547.5 0.0

21965 - no production records -

* production/disposal amounts in barrels

* active oil wells


Due to the rising public concern over environmental degradation,

attention was focussed upon the dumping of waste brine on Michigan

lands (Herold, 1984). Special Order Number 1-81, under Act 61

(P.A. 1939, as amended), was, therefore, issued by the Supervisor

of Veils as a means of controlling oil field brine disposal

practices. Under Special Order Number 1-81 brine can be disposed

of by injection to an approved subsurface formation, through an

approved brine disposal well. Disposal of oil field brine to

pits, however, was banned. As a result of this regulation

subsurface injection has now become the dominant brine disposal

method in the Walker Oil Field. In the study area, disposal wells

apparently are absent, and it is assumed that since 1981 the brine

has been hauled from the well sites and disposed of elsewhere.

Based on production records, it is estimated that nearly

22,900 barrels of brine have been produced from this portion of

the Walker Oil Field (Table 2).


REGIONAL SETTING

Surficial Geology

During the Wisconsinan Stage of Pleistocene glaciation

Michigan was covered with about 305 meters (1000 feet) of drift

deposited by moving ice fronts. In the Woodfordian Substage

periods of ice advancement and retreat developed several different

morainic systems and intervening outwash plains, till plains and

lacustrine deposits (Ten Brink, 1975).

In Ottawa County the Lake Border and the Valparaiso moraines

and associated outwash plains were formed (Figure 5). The Lake

Border and the Valparaiso morainic systems roughly trend north and

south through southwest Michigan. The sediments of these moraines

range in texture from clay to boulders. Interraorainal outwash

plain sediments range from clay to gravel size (Stramel, Wisler &

Laird, 1954).

Subsurface Geology

The Michigan Basin is the dominant structural geologic

feature in the state of Michigan. Rock units overlying the

Precarabrian basement generally thicken and dip toward the center

of the basin. In the deepest part of the Michigan Basin there are

approximately 4572 meters (15,000 feet) of Paleozoic rocks, with

minor thicknesses of Jurassic rocks. Paleozoic rocks at the Walker

Oil Field reach a maximum thickness of 2134 meters (7,000 feet)

(Lowden, 1964).10


11

f > # ? <c # / % i

Figure 5. Map Showing the Approximate Location of Ottawa County Relative to the Glacial Systems in Lower Michigan as Mapped by Leverett and Taylor, 1915.


-C3.

The Traverse Limestone produces oil in the Walker Field from

closure on two broad anticlines. Lowden (1964) proposes that

these structures are the result of the dissolution of the B-Salt

and A-2 Salt beds of the Salina Group, and the subsequent

deformation of the overlying units.

Surface Hydrology

The Walker Oil Field lies within the Grand River drainage

basin. The major stream in this basin is the Grand River, which

drains to the west along the southern margin of the field to Lake

Michigan. Sand Creek drains the western portion of the field and

flows within Tallraadge Township from Section 15 to the south to

its confluence with the Grand River.

Numerous smaller streams, lakes, springs and swamps also

exist within the Grand River drainage basin. Many of the low-

lying swampy areas are found adjacent to the Grand River, often

along the inside of meanders.

Hydrogeology

Nearly all residences within the Walker Oil Field depend on

groundwater through use of private wells. These wells produce

from both the glacial drift and bedrock. Drift wells are used

abundantly because of the good quality and quantity of groundwater

obtained from a relatively shallow depth of usually less than 30

meters (100 feet).


Very few residential wells were completed in the bedrock

aquifer, the Marshall Sandstone. The Marshall Sandstone is often

encountered at 61 or more meters (200 feet) below ground level

and typically contains objectionable amounts of chloride and

dissolved solids.

In Ottawa County confined and unconfined aquifers are found

within the glacial drift. The unconfined aquifers are composed of

glacial sand and gravel units, at or near the ground surface. The

confined aquifers, also composed of glacial sands and gravels, are

overlain by thick impermeable clays and clayey tills.

Perched aquifers also exist in the area. They are usually

small, discontinuous, water-bearing sand and gravel lenses located

within the vadose zone that overlie impermeable clays and clayey

tills.

Mississippian bedrock units underlie the glacial deposits

and include the Michigan Formation, Marshall Sandstone and the

Coldwater Shale. In Ottawa County the Michigan Formation and the

Coldwater Shale are rarely aquifers. Locally they produce small

volumes of water usually of poor quality for domestic use. The

Marshall Sandstone is an important aquifer and produces large

volumes of water (United States Environmental Protection Agency,

1981). Though rarely used for domestic purposes, some industries

do use the Marshall Sandstone for cooling water needs.

The groundwater flow direction in the glacial materials is

different from the flow direction in the bedrock. Within the

drift groundwater flow varies throughout the county. In northern


Ottawa County the groundwater flow direction is generally toward

the Grand River. In southern Ottawa County the flow direction is

expected to be toward Lake Michigan (United States Environmental

Protection Agency, Valker Oil Field Study, in progress).

Regional groundwater flow within the bedrock appears to be to

the east, in the direction of dip, toward the center of the

Michigan Basin (United States Environmental Protection Agency,

Walker Oil Field study, in progress).

Groundwater Quality

Drift wells in Kent and Ottawa counties were sampled during

the 1970's and 1980's by the local health departments, the

Michigan Department of Public Health and the Department of Natural

Resources. The water sampling was done to determine the quality

of the groundwater in domestic wells. Parameters tested for

included chloride and specific conductance.

Chloride and specific conductance data were available for

sixty six glacial drift wells located within the Walker Oil

Field. Depths of wells sampled varied from 9 to 24 meters (30 to

80 feet), with an average depth of 18 meters (59 feet). Chloride

values from these wells ranged from 5 to 1200 mg/L with an

average value of 270 mg/L. Specific conductance in 36 of these

wells showed values that ranged from 500 to 2600 Aimhos/cm,

(Michigan Department of Public Health files).

Similar water quality data were available for only nine drift

wells located outside of the oil field. Well depths varied from


16 to 50 meters (52 to 165 feet), with an average depth of 34

meters (111 feet). Chloride values of the water samples ranged

from 1 to 46 mg/L, with an average value of 8 mg/L. Specific

conductance values varied from 310 to 580 yumhos/cra (Michigan

Department of Public Health files).

Water quality data were not consistent throughout these

counties. The data are skewed since there are many more chloride

and conductivity data available from within the Walker Oil Field

than from adjoining areas, however, there is a significant

difference between the water quality values within and outside the

field. The average chloride value is approximately 30 times less

outside the field. Specific conductances are also notably lower

outside the oil field.

Based on data from Huffman, 1977, 14 mg/L is a generalized

background chloride level for drift in Michigan. This value is in

keeping with the value of 8 mg/L noted in several wells from

outside the Walker Oil Field. No general specific conductance

background level for drift in Michigan has been determined.


STUDY AREA

General Description

Land use in the study area consists mainly of farm and

residential properties. Sparse wooded areas exist adjacent to

Sand Creek. Most of the land is farmed, and current oil

production is limited to parcels within the planted and unplanted

fields.

The area is crossed by two main roads, 14th Street and

Leonard Street (Figure 2). Forty dwellings exist along these

streets, as well as the Tallmadge Township Hall and the Wesleyan

Church. Fourteenth Street receives brine applications in the

summer for dust control and Leonard Street is salted in the winter

for ice control.

Municipal water and sewage disposal are not readily available

in this area. Residents rely on private water supplies, and

domestic waste and sewage are disposed of through individual

septic systems. To improve the quality of the naturally occurring

hard water, nearly two thirds of the residents have water

softeners.

Surficial Geology

In this locale glacial landforms in the study area consist of

the Inner Valparaiso Moraine and the Sand Creek Outwash Plain

(Figures 5 and 6). Surface elevations range from about 195 to 212

meters (640 to 695 feet) above mean sea level, with the higher16


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• v * v:K>>m

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H p lB Kmm^atSsSSmBMf i r a M H l ic M iiP p il

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□ Sand CreekOutwash Plain and lacustrine deposits

Inner Valparaiso Moraine

Study area "boundary

Contour interval 10 feet

oH 500 feetFigure 6. Glacial Landforms in the Study Area (after Ten Brink, 1975).

elevations generally found on the moraine and the lower elevations

on the outwash plain. The land surface slopes gently toward Sand

Creek to the west. Sand Creek and its tributary stream are

incised in the western and northern portions of the site.

Oil well records in the area indicate that the drift

thickness ranges from 29 to 58 meters (94 to 190 feet) (Figure

7). Glacial materials consist of intercalated clay, sand and

gravel. For a detailed description see Hydrogeology subsection.

Subsurface Geology

Bedrock units identified on logs from Walker Oil Field

exploration drill holes include the Traverse Group, Antrim Shale,

Ellsworth Shale, Coldwater Shale, Marshall Sandstone and the

Michigan Formation.

The Middle Devonian Traverse Group is the oldest of the rock

units to be discussed in this report. It is composed of several

thick limestone, dolomite and shale sequences. Gas, oil and brine

are produced in the Walker Oil Field from the Traverse Limestone.

The pay zone in the study area is 1 to 8 meters (3 to 19 feet)

thick. Production is from 566 to 625 meters (1858 to 2050 feet)

deep (Table 1).

The Antrim Shale and the Ellsworth Shale, of Late Devonian

age, overlie the Traverse Group. The Antrim Shale is described as

a light to dark shale unit that ranges in thickness from

approximately 35 to 53 meters (115 to 174 feet). Gas is produced

from this shale unit in Michigan.


19

PRODUCI NG O i l W f U

A 8 A N O O N t O O i l W i l l

* 21 DRIFT THI CKNESS t ) 150

10 FOOT CONTOUR I NTE RVA L

121

94118

125

190

• 100

Figure 7. Site Hap Showing Drift Thickness Based on Oil Well Record Data.


The Ellsworth Shale is a dark silty shale that is not a

producer of petroleum in the state. The upper Ellsworth Shale

averages 6 meters (20 feet) in thickness and the lower rock unit

is about 145 meters (475 feet thick).

The Coldwater Shale is characterized on driller's logs as

dark mud and shale, limestone and red-rock. It is of Early

Mississippian age and it lies above the Ellsworth Shale. This

rock unit is the thickest of the six encountered, ranging from 184

to 226 meters (605 to 741 feet). The Coldwater Shale does not

produce oil or gas in Michigan.

The Marshall Sandstone lies above the Coldwater Shale. This

Early Mississippian rock unit is described as sandstone, shale and

mud. It ranges from approximately 66 to 94 meters (215 to 310

feet) in thickness. And it produces some oil, gas and brine,

though not abundantly.

The Michigan Formation of late Mississippian age underlies

the glacial drift. This formation, characterized as a dark mud or

shale, limestone, sandstone or gypsum, ranges from 0 to 38 meters

(126 feet) in thickness. The "Stray" Sandstone of the Lower

Michigan Formation is known to produce gas and is used for gas

storage.

Bedrock elevation data from oil well records were used to

produce a bedrock surface map (Figure 8). As contoured, this map

shows a northeastern to southwestern trending bedrock valley just

west of the intersection of 14th Street and Leonard Street.


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• 8 8 7

l—l— I— |

Figure 8. Site Map Showing Bedrock (Michigan Formation) Surface Based on Oil Well Record Data.

Reproduced with permission of the copyright owner. Further reproduction prohibited without permission

Surface Hydrology

Surface waters within the study site include Sand Creek and a

tributary, and a swampy area along Sand Creek. Sand Creek is a

perennial stream. Within Ottawa County it is about 21 kilometers

(13 miles) long and drains to the south into the Grand River.

Sand Creek is approximately 195 meters (640 feet) above sea level

at the confluence with its tributary and approximately 180 meters

(590 feet) above sea level at its junction with the Grand River.

The Sand Creek tributary is about 805 meters (half mile) in

length, and roughly bounds the entire study area on the north. It

descends from an elevation of 204 meters (670 feet) above sea

level in the northeast, to 195 meters (640 feet) above sea level

in the northwest where it drains into Sand Creek.

Hydrogeology

In this portion of the Walker Oil Field 19 well records are

available for 38 water wells and geologic logs are available for

ten oil wells. Oil well records provide details of the bedrock

geology. The overlying glacial materials are usually not

described, although the drift thickness of 29 to 58 meters (94 to

190 feet) was noted on the records.

In the study area domestic well depths vary from

approximately 9 to 49 meters (30 t'o 160 feet) below ground level.

Four soil borings were drilled and logged in this area of the

Walker Oil Field by Western Michigan University faculty in 1983.


The boring logs provide descriptions of the glacial materials.

The purpose of installing these borings was to obtain additional

geological information in selected areas. Water well records, oil

well records and soil boring records were used to prepare four

geological cross sections (Figures 9-12).

A single aquifer composed of sand and gravel exists within

the drift. It is overlain by 6 to 18 meters (20 to 60 feet) of

clay and clay till. The thick clay-rich units often produce

confined aquifer conditions. Confined conditions were reported in

nearly all well records but were not observed in the shallow soil

borings. The static water level readings of the borings were

observed immediately after the completion of drilling and were not

allowed to stabilize prior to measuring. Confined groundwater

conditions may have been observed in the soil borings after

stabilization.

Discontinuous lenses of sand and gravel lie within the thick

clay-rich materials. In some cases these sand and gravel lenses

may be water-bearing and of sufficient quantity to sustain a

well. One such perched aquifer produces a non-potable water

supply from less than 6 meters (20 feet) below ground level in the

vicinity of 1587 Leonard Street.

Clay-rich material overlying the sand and gravel aquifer

differ across the study area. Inspection of the soil samples from

soil borings #1 and #2 indicate that the material overlying the

aquifer in the southeastern portion of the study area is

lacustrine in nature with intercalated clay tills. Soil samples


Reproduced

with perm

ission of the

copyright ow

ner. Further


without

permission.

W e s t

A

I 7 0 01 4 51 1 5 0 1 1 4 7 5 1 4 6 3

E a s t

A'

1 4 3 5 1 4 5 71 5 8 7SB 3

gravelyg-HP** clay clay

sand

sandy clay clay

sandT D 4 S f r

TO 61 I tTO 5 8 f t TO 5 9 I t TO 6 3 I tTD 6 3 I i

1— 6 00h-l 1 1 1

SOI I1 0 0 FEET

S A N D A N D G R A V E L [ H a S A N D Y C L A Y £ £ 3 G R A V E L Y C L A Y

POT E N T I OME T RIC 1 5 8 7 L E O N A R D STREET SB 3 SOIL B O R I NG NO. TO TOTAL WELL DEPTHSURFACE____________________________ AQDRE SS

Figure 9. Geological Cross Section Along the South Side of LeonardStreet, Tallmadge Township, Ottawa County, MI. See Figure 2 for A-A' Location.

fo4S

)

!

Reproduced

with perm

ission of the

copyright ow

ner. Further


without

permission.

Z<

- 7 0 0

-6 20

W e st

B

Eas t

/B

14 8 4 1 4 3 0 SB 2

sandy clay

clay

sand gravel

sand

ID 68 It TD 6 7 I I

g r a v e l S A N D Y C L A Y S A N D A N D GRAVEL G RA V E L Y C L A Y

-3Z_ POTE NT I O M E T R I C 1 4 8 4 L E O N A R D STREET S 8 3 S O I L B O R I NG NO. 3 TD T O T A L WELL O E P T H

_________ SURFACE____________ _ _ _ _ _ A D D R E S S

Figure 10. Geological Cross Section Along the North Side of LeonardStreet, Tallraadge Township, Ottawa County, HI. See Figure 2 for B-B* Location.

roUi

Reproduced

with perm

ission of the

copyright ow

ner. Further


without

permission.

S o u t h

C

N o r th

C '

1 2 1 8 0

sandy clay

sandTD 6 0 I t

I D 5 8 I t TD 5 5 I t

T D 7 5 I t .

» «-» I0 1 0 0 F E E T

S A N D Y C L A Y S A N D A N D G R A V E L

V POTE N T 10 M ET R 1C

S U R F A C E1 2 1 0 9 14 TH STREET

AOORESSSB 1 SOI L B O R I N G NO. 1 I D T O T A L WELL DE PTH

Figure 11. Geological Cross Section Along 14th Street, Tallmadge Township, Ottawa County, MI. See Figure 2 for C-C Location.

N iON

Reproduced

with perm

ission of the

copyright ow

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without

permission.

W e s t E a s t

•7 0 0

■6 8 0

clay6 6 0

gravely clayv -— 6 4 0

sandsand62 0

TD 5 9 l l

' 6 0 0

□P O I E N I I O M E I R I C , 5 7 7 L E O N A R D S I R E E I

SUE f AC E ____ A D D R E S S

S A N D Y . G R A V E L Y CLAY

T D I O T A L W E L L D E P T H

Figure 12. Geological Cross Section Along Leonard Street extension, Tallmadge Township, Ottawa County, MI. See Figure 2 for D-D' location.

M

from Soil boring #3 and #4 show that in the northern portion of

the study area the lacustrine deposits are absent, and in general

the clay till directly lies above the sand and gravel aquifer.

The composition, thickness and areal extent of glacial

deposits vary significantly over a short distances (see Figure

9). This may account for abrupt changes in lithology and extent

of a particular glacial unit. However, several well drillers were

involved in the installation of the water wells in the area.

Differences in sampling techniques during drilling as well as

different degrees of detail and accuracy in compiling the well

logs, could also be factors in the variation of glacial materials

shown in the cross sections.

A map of the potentiometric surface was produced from

contouring the static water level data of the 19 water wells in

the study site, and the three wells from just outside the site

(Figure 13). From reviewing this map, it is suggested that a north-

trending groundwater divide exists in the area north of Leonard

Street. Groundwater flows away from the divide in both an

easterly and westerly direction.

Groundwater Quality

Water quality data were obtained by collecting water samples

from domestic wells and soil borings located within and just

outside of the Walker Oil Field during the summers of 1983 and

1984. Forty three wells and two soil borings were sampled. Water

samples collected from wells were tested for chloride by


29

□eeo8 5 0 ST AT I C WATER I E V E L ( F T )

G R O U N D W A T E R F L O W 01 R E C T I O N

G R O U N O W A T E R D I V I D E

5 F O O T C O N T O U R I N T E R V A L

8 3

s«n

8 4 609530680

5 2 06ST □

Figure 13. Groundwater Flow Direction Based on the Potentioraetric Surface of the Study Area.


titration, and were tested for specific conductance with a

portable conductivity meter (Wagner, 1988). Soil boring water

samples were collected in the summer of 1984. These water

samples were tested for chloride. Table 3 lists domestic well

and soil boring depth and location, as well as water quality

data.

The water quality data obtained from the well samples were

used to create two separate maps, a chloride isoconcentration map

and a specific conductance map (Figures 14 and 15). Several

important observations can be made from these maps, including the

following five:

1. The pattern of both maps is similar.

2. Three adjacent and discrete chloride plumes exist in

about the middle of the study area.

3. The plumes are elongate in shape.

4. The plumes appear to originate from or are associated

with several abandoned oil wells.

5. As drawn the central and the eastern-most plumes appear

to have moved in a westerly to southwesterly direction. The

western-most plume is likely to migrate in a westerly to north

westerly direction. The orientation of the plumes is related to

their locations with respect to the local groundwater divide

described in the groundwater flow map (Figure 13).

6. The central plume includes the highest concentrations of

chloride and specific conductance.


Table 3

Water Quality Data and Domestic Well and Soil Boring DepthC h lo r id *

< "0 /L )Spec. Conductance

f*e tios/on)Depth

( i t ) Lo ca tio n

167 - Ur* 1376 Leonard

32 740 160 1365

140 960 40 1439 *

106 900 60 1424 •

190 1000 U * 1426

411 1600 67 1438/1430

136 1000 66 1492

165 1000 63 1435 •

496 3000 91 1451 *

100 725 61 1457

616 1900 69 1469

113 830 66 1475

722 2600 66 1480 •

642 - u r* 1494

662 2000 67 1600

M l 1600 63 1601

90 660 63 1609 *

404 1600 u r* 1810

906 1200 60 1625 *

190 - u r* 1626

66 610 92 1635

344 1600 78 1542

170 1200 61 1545

67 760 69 1577

962 1600 66 1667

83 - 160 1638 *

434 1700 76 1685 *

“ 1200 68 1723 *

166 - Ur* 1805 *

33 - 67 1624 a

293 1400 60 12109 14 th

424 1700 66 12116 a

66 725 63 12134 *

370 1200 78 12135

66 160 65 12160 '

190 1100 Ur* 12155

143 990 Ur* 12177

79 700 38 12160

66 660 u r* 12187

14 660 u r* 12303

6 676 u r* 12320

30 - 30 12463 a

76 76 12456

60 - 40 S o il Bor 1no e 1

- - 46 • • 2

- - 40 • • 3

60 — 40 • • 4


32

30 □PR O D U C I N G O i l W E l l

• •

*□

i d!?<>□o a170|5 7

730

85 0

SO40/. 1 »ODV ^ -20 O—̂ 2 7 on0—

^ S ^ ? 5 :V 2 9 3uyo c X m ]

)C V '* 0D

83

1 3tO

Figure 14. Isoconcentration Map of Chloride (mg/L) of Domestic Well Water (values collected by Wagner, 1988).


33

H O L D I N G T A N K S

NCE

V A L U E S ' / i m h o t / c m

5 0 0 / i m h o i ' c m CONTOUR I N T E R V A L

5 0 O« o O

00 □7 6 0

0 0

OOQ7 0 o D

66 O D

00 2 0 011 o o D

> * < 1 0 □1 8 0 C 20 6 0 0

7 2 « □1 7 0 0 |o D

<>□000I 8 0N.

7 4 0 D100,

9 OOQ5 00

Figure 15. Map of Specific Conductance Cumhos/cm) of Domestic Well Water (values collected by Wagner, 1988).


In the study area domestic well depth varies from

approximately 12 to 49 meters (38 to 160 feet), with an average

well depth of 18 meters (60 feet). The chloride contamination

appears to be separated into three discrete plumes. It is likely

that inconsistencies in chloride values, such as the two low

values on the north side of Leonard Street, are actually due to

sampling problems. Sampling problems may be due to such factors

as the uncertainty of well depth, as only about half of the

domestic wells had well logs prepared for them.

The chloride isoconcentration map indicates that levels of✓

chloride in the groundwater range from 14 to 722 rag/L. A

secondary Recommended Maximum Contaminant Level (RMCL) of 250

rag/L has been established by the United States Environmental

Protection Agency (U.S.E.P.A.) for chloride in drinking water

(Driscoll, 1986). This limit is based on the aesthetic quality

of the water.

Thirteen of the water samples tested for chloride detected

levels greater than 250 mg/L. The highest chloride levels were

within plumes in the middle of the study area, on either side of

Leonard Street. The lowest chloride levels were found in the

northeast, above the Sand Creek tributary, and in the northwest,

just below the tributary. Outside of the study area, just north

of the site on 14th Street, the lowest chloride level was

detected at 5 mg/L. It is inferred that chloride levels of


35approximately 5 to 75 mg/L represent background levels (also see

Regional Groundwater Quality Section).

Specific conductance is considered an indication of the

amount of total dissolved solids. The U.S.E.P.A. has developed

an RMCL of 500 mg/L for total dissolved solids. The specific

conductance map, shows values ranging from 550 to 2600

Aunhos/cm. The highest specific conductance values were found in

the middle of the site along Leonard Street. The lowest values

were found in the northeast and the northwest, and east of 14th

Street. The locations of the high and low specific conductance

values are similar to those of the chloride values.

Two soil borings were sampled for chloride. The water

samples were collected from each boring immediately upon reaching

the water-bearing zone. Samples from soil boring #1 and #4 show

60 and 50 mg/L chloride, respectively.


REVIEW OF ELECTRICAL RESISTIVITY USED IN HYDROGEOLOGICAL PROBLEMS

One of the earliest uses of DC resistivity in groundwater

application was exploring for potable water supplies. Often the

search for substantial water supplies involved defining the

boundary between the fresh-water and salt-water zones in a given

aquifer. Swartz, 1939, accomplished this in the Hawaiian

Islands.

Warner (1969) attempted to delineate the fresh-saline water

interface in the aquifers of several sites in New York and in

Texas. Apparently the surface resistivity method was able to

accomplish this task at most all sites except when the zone of

saturation, overlying the saline zone, was very thin with

respect to its depth below ground level.

Since the late 1960's surface electrical resistivity

surveys have been used abundantly in hydrology for groundwater

contamination studies. Cartwright and McComas (1968) conducted

a resistivity survey at an Illinois landfill which was

successful in detecting the direction and the distance of

contamination movement off the landfill site.

Fink and Aulenbach, 1974, were also able to define the

direction of groundwater flow from a resistivity study conducted

at a site in New York where sewage effluent was discharged onto

sand beds.

Electrical resistivity surveys were carried out at four

industrial and landfill sites by Stollar and Roux (1975).36


Through three of the surveys the lateral extent of groundwater

contamination plumes was defined. One study was not successful,

though, due to such factors as deep water table, and

insufficient resistivity contrast between contaminated and

uncontaminated groundwater.

Many hydrogeological studies involving resistivity have

been conducted recently in the United States. Fretwell and

Stewart (1981) successfully defined the fresh-water/saline-

water contact in a limestone aquifer of a karst area of

Florida.

Bisdorf (1983a) employed this geophysical method to

trace geothermal zones within basalt and rhyolite flows

of the Newberry Caldera of Oregon. Bisdorf (1983b) was able

to map fresh water zones in terrace gravels of Idaho with the

electrical resistivity technique. Problems with cultural

features, however, did make site selection of the

resistivity stations less than optimal.


EREVIOUS WORK IN THE WALKER OIL FIELD AREA

The Walker Oil Field area has been investigated by others in

the past in attempts to locate bedrock structures, and to define

areas of groundwater contamination. Lowden (1964) conducted a

gravity survey in the Field and was successful in locating salt

beds of the Salina Formation.

Wagner (1988) and Meisel (1985) conducted separate

hydrogeological investigations of the oilfield. Wagner studied

groundwater quality of domestic wells in several counties,

including Kent and Ottawa. She detected several areas where

sodium, chloride and specific conductance values were elevated,

which she suspects may be due to the production and disposal of

oilfield brines.

Meisel (1985) conducted an electrical resistivity study in

Kent county in an attempt to map groundwater contamination

associated with oilfield brines. The technique was not

particularly successful in defining zones of groundwater

contamination because of interference from conductive clays, but

did describe a complex shallow aquifer system.

A similar geophysical survey was attempted by Michigan

Department of Natural Resources (MDNR) previous to Meisel's

investigation. The survey was not completed in part because in

their opinion cultural interferences precluded the application of

DC surface resistivity techniques.

38


ELECTRICAL RESISTIVITY

Definition

Resistivity is the bulk or three-dimensional property of a

substance which opposes the flow of electrical current. Surface

electrical resistivity is a geophysical technique in which an

electrical current is introduced at the ground surface between a

pair of electrodes, allowing for measurement of electrical

potentials at another pair of electrodes, and hence the

computation of an apparent resistivity at that location.

Uses

Surface electrical resistivity is a valuable means of

collecting geological and hydrogeological data from the

subsurface. Some of the geological data that are obtainable

from employing this geophysical method are as follows:

1. geological structures: folds, faults, intrusion

2. sedimentological features: large scale bedding,

gradation

3. lithological changes: general composition, litholo-

logical boundaries

4. glacial features: buried valleys, stream channels

5. natural resources: minerals and ores, geothermal

reservoirs, water supplies (Mooney, 1980).

39


40The following aspects of the hydrogeological environment

are also described through surface electrical resistivity:

1. groundwater quality: fresh versus saline water

sources, inorganic contamination plume

2. glacial deposits: drift thickness, sand and

gravel zones (potential aquifers), clays (aquitards)

3. hydrology: perched aquifers, water table

4. fracture directions: study of directional variations

of resistivity.

In addition to geological and hydrogeological data,

surface electrical resistivity can supply information regarding

land use and cultural phenomena.

Factors Governing Resistivity of Rock Materials

Resistivity of consolidated and unconsolidated rock materials

is controlled by various parameters. Included among these

parameters are the degree of saturation and composition of water

retained in the pore spaces, porosity and compaction of rock

materials, and mineralogy (Dobrin, 1960).

Surface electrical resistivity is generally used to obtain

information about geologic materials existing below the water

table. Saturated materials are discussed in greater detail

herein than unsaturated materials.

In the zone of saturation, where most of the void spaces of

rock materials are 100% water-filled, the chemical make up or


salinity of water contained in these materials is one of the most

significant parameters influencing resistivity. The value of

resistivity will be a function of the volume, mobility and the

dissociation of the dissolved ions in water (Dobrin, 1960).

The mode of transportation of an electrical current in the

saturated zone is through the dissolved ions in water. An

increase in salinity of pore water results in a decrease in

electrical resistivity, all other properties being constant.

The porosity of the saturated rock materials will directly

effect the amount of pore water contained in the rocks. An

increase in porosity, causing an increase in water saturation,

will commonly result in a resistivity decrease. Highly porous

clays will typically exhibit lower values of resistivity than will

sands and gravels, due to increased porosity. Massive limestone

having low porosity usually displays high values of resistivity.

Increasing water saturation up to about 50% results in a rapid

decrease in resistivity. Increasing from about 50% to 100%,

however, results in a slow decrease in resistivity (Mooney,1980).

Compaction of rock materials can affect the overall

resistivity values. An increase in compaction often results in a

decease in porosity, and therefore an increase in resistivity.

Geologically older rock units generally have high values of

resistivity due to compaction of sediments from increased

overburden (Dobrin, 1960). Igneous and metamorphic rock types are

commonly among those having relatively high resistivity values.


Pore water characteristics are most significant in

determining resistivity of rock materials in the zone of

saturation. Rock mineralogy is often only of secondary

importance.

In the unsaturated zone, where only residual quantities of

pore water are retained, the dominant resistivity-controlling

influence is rock mineralogy. An electrical current introduced at

the ground surface will flow directly across the mineral grains of

the rock materials in this zone (Dobrin, 1960).

In unsaturated, unconsolidated, rock materials resistivity

values commonly vary from about 1 to 800 ohm-raeters (Table 4).3

Sandstone can reach approximately 6 x 10 ohm-meters, while clays

in the temperate environment show relatively low resistivity, 1 to

100 ohm-meters (Telford, Geldart, Sheriff & Keys, 1976).

Field work of the United States Geological Survey (U.S.G.S.)

including deep resistivity well logs, suggest that resistivity

values of the saturated shallow sand and gravels in the northern

Michigan Basin in Michigan, range from 100 to 300 ohm-meter (D.

Westjohn, personal communication). In southwestern United States

resistivity values are characterized from about 15 to 20 ohm-

meters (Zohdy, 1965).


Table 4

Electrical Resistivity Values of Geological Materials (after Telford 1976)

Geological MaterialsResistivity Averages and Ranges (jl.m)

Alluvium and sands 10 - 800

Clays 1 - 100

Unconsolidated wet clay 20

Sandstone 1 - 6.4 x 108

Limestone 50 x 107

Shale (consolidated) 2 0 - 2 x 104

Saline waters (3%) 0.15

(20%) 0.05

Natural Waters (sediments) 1 - 100

Soil Waters 100

Surface Waters (sediments) 10 - 100

Meteoric Water 30 x 103

Sea Water 0.2


44

Types of Electrode Configurations and Exploration Methods

Many types of electrode configurations or arrays can be used

when employing surface electrical resistivity. Most of the arrays

consist of four co-linear electrodes arranged so that the outer

electrode pair introduces the electrical current (I) into the

ground surface, while the inner pair measures the resulting

potential difference (V).

Resistivity values obtained from conducting an electrical

resistivity survey at the earth's surface are defined as apparent

resistivity values ( / ). These values are influenced by the

electrical current penetrating the many geoelectrical layers

making up the subsurface (see Theory section).

The two most common arrays presently used in the United

States in groundwater investigations are the Schlumberger and the

Wenner arrays (Zohdy, Eaton & Maybey, 1974). In the Schlumberger

set up the current electrodes (AB) and the potential electrodes

(MN) are kept laterally symmetrical about the geometricaI center

of the spread (Figure 16). The AB electrodes are expanded

continuously during the survey, while the MN electrodes are only

moved infrequently. In general the MN electrodes are kept close

together, such that MN is less than or equal to 1/5 AB

(Mooney,1980). The MN electrodes are expanded when the potential

drop falls below the precision desired. This array geometry

allows for detecting resistivity changes resulting from


45

M -G>-

Figure 16. Schlumberger Electrode Arrangement.

A ----- ------ K

7 J* 1 / '

' I

Figure 17. Uniform Three Dimensional Current Flow.

Y®i I

/ * SOOJL'm

/ * 1 0 0 0 j i * m 2

»1 > ° 2

Figure 18. Distortion of Current F l o w Lines When f^rnssi — »E the Boundary Between Media of Differing Resistiv- ^ i t y .


inhomogeneities present at the ground surface near the electrodes,

which can affect the overall apparent resistivity reading.

The following equation is used to determine the measured

apparent resistivity when using the Schlumberger array on a planar

surface or half space:

/ =^/4 . a

This equation is based on the array geometry, the electrode

separation, the applied current and the measured potential

difference.

The Schlumberger electrode configuration has the following

advantages over the Venner array:

1. The survey can be completed relatively quicker and

cheaper, as fewer personnel are required.

2. The array is less affected by near surface

inhomogeneities because the MN electrodes are expanded

infrequently.

3. This electrode configuration has a somewhat greater depth

of investigation and better resolution (Zohdy et al., 1974).

In the Wenner array set-up the AB and MN electrodes are kept

laterally symmetrical about the midpoint of the array. The

distance AM » MN - NB - a.

As opposed to the Schlumberger array, both the AB and MN

electrodes are expanded simultaneously. The equation needed to

(AB)2 - (MN)2(MN)

VI (1)


determine the apparent resistivity values in employing the Wenner

array is as follows:

An advantage of the Venner array is that it measures a larger

potential difference signal than does the Schlumberger array. It

is, however, more easily affected by near surface inhoraogeneities

and telluric currents, due to the repeated relocation of the MN

electrodes (Telford et al., 1976).

Two common methods of surface exploration are vertical

electrical sounding (VES) and horizontal profiling (HP) methods.

In the VES method, there is a fixed center point around which AB

and MN electrodes are systematically expanded, thereby providing a

progressively deeper penetration of electrical current.

With the HP method the array is moved as a whole along a

given traverse at the earth's surface. A constant electrode

spacing is maintained throughout the survey. By moving the entire

array at each station of the survey, it is possible to note

lateral changes in resistivity at a certain depth.

Both Schlumberger and Wenner arrays can be used in either

sounding or profiling surveys. For this study the Schlumberger

array was used to conduct vertical electrical soundings. This

array was chosen to avoid problems with lateral inhomogeneities

expected to exist in glacial materials overlying the study area.

Vertical electrical soundings were needed in order to obtain

information about the subsurface at unknown depths.

(2)


48Theory

Resistivity measurements collected at the earth's surface are

calculated assuming uniform resistivity and, therefore, isotropic

and homogeneous subsurface conditions. Since the subsurface is

actually not isotropic and homogeneous, results of four-electrode

resistivity surveys conducted on the earth's surface are referred

to as apparent resistivity (or f ) values. If a resistivity

survey is conducted over isotropic and homogeneous media, then the

true resistivity ( is determined. values are almost

exclusively measured under laboratory conditions.

Electrical current introduced into a homogeneous and

isotropic media will result in a uniform three dimensional current

flow pattern, semi-cylindrical in shape (Figure 17).

As mentioned previously, the earth is inhomogeneous and

anisotropic in nature. The current flow pattern will become

distorted under these conditions, with current concentrating in

low resistivity media. As current flow lines cross boundaries of

differing resistivities, the flow lines change. Current flow

lines bend toward the normal when crossing into higher resistivity

media, and bend away from the normal when crossing into lower

resistivity media (Figure 18).

The distortion of the flow lines cause a change in the

potential drop reading, resulting in a change in f (Figure 19).cl

The depth of current penetration is a function of the layering

structure of the earth, and the length of the AB/2 separation


49

Figure 19

i— G >

a)I V s 11' l \

- A -

- - _

S •» — *— CD-

✓ i

- h -

B

b) * *r"■ V-v -g- 3 _ <• f A

12

c)

©-

7JV/ r ' ~ - ' i x r-v- *

d)

— © -

A

Changes in Layer Thickness (h) and Electrode Separation Influence Current Flow Direction.a) Little influence from layer 2 where h, > h„ andr < / ■ 1 21 2*b} current flow is greatly influenced by layer 2, but most of the current is concentrated in layer 2, where h < h2 andc; Current flow is greatly influenced by layer 2, where AB is large;d) little influence from layer 2, where current electrode is small (after Mooney, 1980).


(Dobrin, 1960). A more detailed discussion of the theory of

electrical resistivity is found in Zohdy et al., 1974; Mooney,

1980; and Dobrin, 1960.

Field Methods

Figure 20 shows the locations of 56 VES's completed using the

Schlumberger array. It also indicates the locations of several

geoelectric sections (GSA - GSI). Each geoelectric section

consists of several VES's that are generally equidistant to one

another and are arranged in a straight line. In Geoelectric

Section C - F the geoelectric sections were oriented perpendicular«■to the proposed groundwater flow direction. This particular

orientation was chosen in order to define the lateral boundaries

of the groundwater contamination plume(s), expected to exist in

the shallow aquifer.

Both the current and potential electrodes were expanded about

the geometric center of the array. Each expansion was

approximately 1.46 times greater than the preceding length.

Current electrodes (AB) were expanded to large distances, ranging

from 100 to 316 meters (328 to 1037 feet)(Figure 21). Cultural

interferences such as buildings and fences, sometimes prevented

moving the electrodes all the way to 316 meters (1037 feet).

Typically the maximum AB/2 expansion was 147 meters (482 feet).

At a few VES's 100 meters (328 feet) was the largest separation

possible. The maximum MN/2 separation was 15 meters (49 feet).


5 1

VES STATION12GEOEIECTR IC SECTION

S O I t BORING

ACTIVE! AB AN D O N ED O i l W E t l S

H O ID IN O TANKS

□

9OS H22 CR23

G S I3 0

□2*3 2

S 0 0

Figure 20. Map Showing the Locations of VES and Geoelectric Sections.


52

Project! Tallm adge Township - O ttaw a C o .. Ht • VES H o .

Location: a p p ro x . 100 m w es t o f 1 4 th S t ! 250 m . Date! 8- 22-81 n o r th o f Leonard SC.

Operator! K o e h le r e t al Equip.Conditions: c lo u d y - h o t - damp

ForwardV / I

ReverseV / I

AD/2 ( “ )

MN/2 < - >

K V / I(JL)AvG.

A5-71 • m ) smoothed v a lu e s (jll'm )

4 .9 6 4 .7 0 1 .0 0 .1 5 10.2 4 .8 3 4 9 .3 60 .0

1.79 1.74 1.47 0 .1 5 22.4 . 1 .77 3 9 .6 48 .2

0 .688 0 .605 2 .1 5 . 0 .1 5 4 8 .2 0 .647 31.2 3 8 .0

0 .300 0 .317 3 .1 6 0 .1 5 1 04 .0 0 .309 32.1 39.1

0 .191 0 .191 4 .6 4 0 .15 2 25 .0 0 .191 4 3 .0 52.3

0 .131 0 .131 . 6 .81 0 .1 5 4 8 5 .0 0 .131 6 3 .5 77.3

0 .561 0 .505 6 .81 0 .5 145 .0 0 .533 7 7 .5 __0 .333 0 .336 1 0 .0 0 .5 3 13 .0 0 .335 104 .9 l n r>. o

0 .207 0 .207 14.67 0 .5 675 n O. 207 11Q 7

0 .123 0 .123 21.54 0 .5 1457.0 0 .123 179.2 187 .0

0.403 0 .398 21.54 1 .5 4 8 4 .0 0 .401 194.7

0 .208 0.231 31.62 1 .5 1045.0 0 .2 2 0 229 .9 230 .0

.0 .0 8 8 0 .116 4 6 .4 1 1 .5 2 2 5 3 .n n m 2 220 n

0 .038 0 .043 6 8 .13 1 .5 4 85 8 .0 0 .041 199.2 197.00 .133 0.133 68.13 5 .0 1450.0 0 .134 194.3

0 .043 0 .043 100.0 5 .0 3134 .0 0 .043 134.8 135.0

0 .012 0 .021 146.7 5 .0 6753 .0 0 .033 222 .8

0 .015 * 0 .015 215.4 5 .0 14570.0 0 .015 218 .6

0 .035 0.031 215.4 15 .0 4 8 3 5 .0 0 .033 1 5 9 .6

' 0 .022 0.021 116.2 15.0 10450.0 0 .022 2 29 .9

■E lfiV fltl in - i« -a p r m ----68 R I

Figure 21. Sample of Field Data.


At the majority of the VES's only a five meter (16 foot) maximum

separation was used.

At each electrical sounding the current electrode separation

was increased, and external voltage was applied across the current

electrodes, causing an electrical current to flow through the

earth. The resulting electrical potential (V) was then measured

between two potential electrodes, and the apparent resistivity was

calculated.

This procedure was repeated at each station of a sounding.

When the electrical potential reading had dropped to a very small

value, it was necessary to expand the MN electrodes. The accuracy

of the measured electrical potential was improved by expanding the

MN electrodes when the value of MN approximated l/20th the AB/2

value.

Apparent resistivity measurements were made before and after

the expansion of the MN electrodes, while the AB electrodes

remained stationary. Calculated apparent resistivity values at

each station of each VES were plotted against the respective AB/2

values on log paper to generate field curves of apparent

resistivity. Data points that appeared to be inconsistent with

the field curve were repeated to check their validity.

An average of the forward and reverse V/I readings was then

calculated for each station of a given VES. Apparent resistivity

values were computed using formula 1 (see Types of Electrode

Configuration and Exploration Methods section). The V/I values


were read directly from the resistivity meter. On the field data

sheet K equals the following:

K - #74 . (AB)2 - (MN)(3)(MN)

After collecting about 17 apparent resistivity readings at a

given VES, the field equipment was moved approximately 50 meters

(164 feet) to the next VES site and the entire process was

repeated.

Apparent resistivity readings were collected before and after

expanding the MN electrodes, while keeping the AB electrodes

fixed. This procedure caused an overlap of points, and

segmentation of the apparent resistivity curve. When surface

materials near the MN's are homogeneous, both apparent resistivity

values collected before and after expanding the MN's are similar,

and the resulting curve segment is slightly displaced to the right

(Figure 22). When the surrounding surface materials are

heterogeneous, the values of apparent resistivity readings before

and after the MN expansion are quite dissimilar. This results in

a large curve segment offset to the left of the previous segment.

Use of the Schlumberger apparent resistivity method, therefore,

allows the user to interpret the effect of surface inhomogeneities

adjacent to the MN electrodes. As noted in Figure 21, two

apparent resistivity measurements were collected at AB/2 = 6.81,

21.54, 68.13 and 215.4 meters (22, 71, 224, and 707 feet,

respectively).


55

log p0

log L

Figure 22. Hypothetical Schlumberger Field Curve Showing Curve Segment Displacement.


56

To avoid recording potentials caused by electrochemical

activity between the metal contacts of the electrodes and

electrolytes of the soil, two precautions were taken:

1. Non-polarizing Cu-CuSO^ potential electrodes

were used.

2. A reversing switch was used to change the direction of

current between the metal stakes, used as current electrodes.

Thus the signal polarities were alternately reversed and

the constant spurious potentials were canceled out (Dobrin,

1960).

Data Reduction

In order to interpret the significance of the collected field

data, the following three stages of data reduction were

followed:

1. Each apparent resistivity curve was smoothed and visually

inspected.

2. Trial subsurface resistivity models were examined through

the use of the computer program RESIST, and the program INVERS

was used to refine the model to best fit the field curve.

3. A longitudinal conductance map and several geoelectric

sections were constructed.


57

First stage

To simplify an apparent resistivity curve, inconsistencies in

the curve had to be adjusted and smoothed through. Resistivity

data from Schlumberger soundings, represented by unconnected curve

segments, were shifted and joined together to form one continuous

field curve.

All 54 apparent resistivity curves were segmented.

Segmentation of Schlumberger apparent resistivity curves was

caused by plotting the double readings of apparent resistivity

collected at subsequent MN separations, while the AB/2 spacings

remained constant (see Field Methods Section).

Cusps, abrupt changes in the curve shape, also had to be

smoothed. Nine curves appeared to have cusps. The cusps are

expected to have been caused by buried cultural factors or leakage

of electrical current. Smoothing through the curve segments and

the cusps of each apparent resistivity curve helped to clarify the

particular shape of the curve, allowing for their interpretation.

Through a cursory visual examination the minimum number of

geoelectric layers, their relative apparent resistivity values,

and the curve types were inferred. The number of geoelectric

layers were discerned by noting the rises and falls of the

apparent resistivity curves. In Figure 23, for example, VES #2a

is depicted by five geoelectric layers, assumed from the initial

inspection. It is possible, however, that more than five

geoelectric layers may in fact exist in the subsurface due to


58

Tallmadge Twp. - Ottawa Co., HI 2aapprox. 25 m so. o il tank serv. rd;100 m west 14th St. 9-17-83

IC - 69 (loaner)

very damp - cool - cloudy ___

Figure 23. Sample of Study Area Field Curves.a) Segmentation of the field curve;b) Same curve after smoothing.


factors such as suppression, in which a given geoelectric layer

may not be uniquely represented on the particular apparent

resistivity curve. A geoelectric layer may be suppressed if its

thickness is small when compared with its depth of burial. Thus a

thin geoelectric layer might be averaged with thicker geoelectric

layers lying above or below it. To improve the reliability of the

inferences made for visual examination of apparent resistivity

curves, supplemental geological, hydrogeological and groundwater

quality data were utilized as control, to yield a better

understanding of the makeup of the subsurface.

A rough estimate of the apparent resistivity value of each

curve segment was read from the ordinate axis on the curve plot.

Apparent resistivities from VES #2a are noted as 220, 75, 135, 70

and 200 ohm-meters (Figure 23). These values are crude

approximations of apparent resistivity values only, as each

geoelectric layer is influenced by the geoelectric layers

surrounding it.

The type of each apparent resistivity curve was determined by

the relationship between the resistivity and thickness of the

geoelectric layers (Figure 24). If more than three layers

characterize the subsurface, the curve types can be combined to

represent the particular geology. VES #2a, made up of five

layers, denotes an HKH-type curve.

The 54 apparent resistivity curves reviewed were judged to

have from three to seven geoelectric layers. The majority

consisted of five such layers, representing the HKH-type curve.


60

1)

2)3)

4)

Figure 24.

where > < 4 H-type curve

where ' i < > K-type curve

where / i > A > ^3 Q-type curve

where ' i < < ^3 A-type curve

Four Basic Relationships Exist Between Resistivity and Thickness in a Three-Layered Subsurface:1) Represents a minimum or H-type curve,2) Represents a maximum or K-type curve,3) Represents a descending or Q-type curve,4) Represents an ascending or A-type curve

(after Zohdy et al, 1974).

Second Stage

The number of geoelectric layers and layer resistivity values

were obtained through visual inspection of the apparent

resistivity curves. Layer thickness was estimated by reading the

values from the. abscissa of each resistivity curve plot. These

data were combined to create a initial model of the subsurface

used with the interpretational computer program, RESIST. The

RESIST program generated a theoretical curve, based upon the input

initial model, which was then superimposed on to the field curve.

The initial model was modified when needed, by the user to improve

the fit between the curves. RESIST, therefore, acted to improve

the initial model of each apparent resistivity curve from the

first stage of data reduction.


RESIST was utilized when reviewing only the first few

apparent resistivity curves. With the exception of double

checking the rough model gathered from visually reviewing a few

atypical curves, the RESIST program was eventually discontinued,

in order to expedite the curve evaluation process. In the opinion

of this write, the model obtained in visually inspecting the

apparent resistivity curve (First Stage) was usually sufficient to

use as the initial model in the second computer program, INVERS.

INVERS is a computer program designed to determine a layered

earth model whose calculated apparent resistivity curve closely

agrees with the curve of the field data (Mooney, 1980). The trial

model (obtained from RESIST) layer resistivity and thickness

values were input into the INVERS computer program, representing

the initial layered earth model. The program then determined an

apparent resistivity curve for these data, which was compared with

the field curve. A root mean square (RMS) error value was then

computed, based on the dissimilarities between the curves. The

average RMS was 4.8% for this research.

The initial model was iteratively adjusted automatically

until the model had passed through 15 iterations, until the RMS

error began to increase (diverge), or until the RMS error fell

below a pre-set cut-off value (Mooney, 1980). To improve the RMS

error between the final calculated layered model and the field

data model, the process was repeated, with the user making

adjustments to the new model. Geological data was used as control


f o r c o m p a r i s o n w i t h t h e s o u n d i n g s d o n e n e a r w a t e r w e l l a n d s o i l

b o r i n g l o c a t i o n s . T h e m o d e l w a s g r e a t l y i m p r o v e d w h e n t h e l a y e r

t h i c k n e s s e s o f g e o l o g i c a l f o r m a t i o n s , f o r e x a m p l e , w e r e k n o w n .

T h e INVERS c o m p u t e r p r o g r a m o f f e r s a m e a n s o f t y i n g i n

s u p p l e m e n t a l g e o l o g i c a l i n f o r m a t i o n , b y a l l o w i n g e i t h e r o r b o t h

t h e r e s i s t i v i t y a n d t h i c k n e s s o f o n e o r m o r e g e o e l e c t r i c l a y e r t o

b e h e l d f i x e d w h i l e t h e o t h e r p a r a m e t e r s w e r e a l l o w e d t o v a r y .

A l s o c a l c u l a t e d i n t h e INVERS p r o g r a m f o r e a c h g e o e l e c t r i c

l a y e r w e r e t h e D a r Z a r r o u k p a r a m e t e r s , l o n g i t u d i n a l c o n d u c t a n c e

( S ) a n d t r a n s v e r s e r e s i s t a n c e ( T ) . S » t h i c k n e s s / r e s i s t i v i t y f o r

a m in im u m r e s i s t i v i t y l a y e r , a n d T - r e s i s t i v i t y x t h i c k n e s s f o r

a m ax im u m r e s i s t i v i t y l a y e r . T h e s e p a r a m e t e r s w e r e u s e d t o d e f i n e

a p a r t i c u l a r c u r v e s e g m e n t o f a n a p p a r e n t r e s i s t i v i t y c u r v e . By

h o l d i n g c o n s t a n t t h e S p a r a m e t e r f o r c u r v e s e g m e n t s r e p r e s e n t i n g

a r e s i s t i v i t y m in im u m , a n d t h e T p a r a m e t e r f o r c u r v e s e g m e n t s

r e p r e s e n t i n g a r e s i s t i v i t y m axim um l a y e r , t h e c o m p u t e d t h e o r e t i c a l

c u r v e w o u l d n o t d e v i a t e g r e a t l y f r o m t h e f i e l d c u r v e . S e v e r a l

l a y e r e d e a r t h m o d e l s , t h e r e f o r e , c o u l d b e p r o d u c e d f r o m t h e s am e

f i e l d d a t a .

A l l a p p a r e n t r e s i s t i v i t y c u r v e d a t a w e r e r u n t h r o u g h t h e

INVERS c o m p u t e r p r o g r a m , w i t h t h e e x c e p t i o n o f VES # 8 . A l a y e r e d

e a r t h m o d e l o f l e s s t h a n o r e q u a l t o 10% c o u l d n o t b e d e t e r m i n e d

t h r o u g h t h e INVERS c o m p u t e r p r o g r a m . I t i s p o s s i b l e t h a t a b u r i e d

c o n d u c t o r , s u c h a s a p i p e l i n e , e x i s t s i n t h e s u b s u r f a c e i n t h e

v i c i n i t y o f VES # 8 . T h e VES # 8 s o u n d i n g c u r v e a p p e a r s t o b e


anomalous in character and was, therefore, not included in the

data used to interpret the subsurface of the study area.

Third Stage

The interpreted resistivity data obtained from INVERS

computer models were used to construct nine geoelectric sections

(Elates 1-3 and Appendix E). Data from domestic wells, oil wells,

soil borings and from water samples were correlated with adjacent

vertical electrical soundings and were incorporated into the

geoelectric sections. Based upon the curve similarities these

data were extrapolated to the next adjacent sounding in a

continuous manner. The method of constructing the sections was

similar to that used in preparing geological cross sections.

The longitudinal conductance (S) map was created by adding

the S values at each VES, exclusive of the highly variable

surface layer, as noted in the output from INVERS (Appendix C).

where h^ represents the sum of the thickness of the geoelectric

layers, and denotes the sum of the resistivity of the

geoelectric layers. The S values then were plotted and contoured

at 0.2 mho contour interval (see Interpretation of Field Data -

Longitudinal Conductance Map) (Figure 25).


64

0.47 10 N Gl T UDI N A L CONDUCTANCE 0 VAL UES(mhot)-EXCLUSIVE 07

FIRST LAYER

A C T I V I / A 8 A N O O N E D O l L WELLS

• » H O L D IN G TANKS

.2 mho CONTOUR INTERVAL

1.080.07

,0.10

'1.38*

1.2

Figure 25. Map o£ Longitudinal Conductance (mhos).


Interpretation of Field Data

True resistivity values of field-collected soil samples, were

measured and calculated in the laboratory. These values were used

to verify the interpreted resistivity values that were calculated

by the computer program INVERS, for the different geoelectric

layers. This was especially important for the dry and saturated

sands and gravels of the drift aquifer. An overall good

correlation exists between the interpreted resistivity and true

resistivity values. Sometimes, however, the interpreted

resistivity values differ from the true resistivity values. This

appears to occur when more than one geoelectric layer was

represented by a single interpreted resistivity value. For

details on the method of laboratory testing refer to the Lab

Procedures section.

Water quality data from domestic well and soil boring

sampling were included in the respective geoelectric sections for

added reliability. Chloride was one of the parameters tested for.

Values of chloride ranged from 14 to 722 mg/L, with background

levels equal to about 75 rag/L or less (see Ground Water Section).

In general areas of elevated chloride concentrations correspond to

areas of low resistivity. Low chloride concentrations are also

associated with areas of high resistivity.

The interpreted resistivity of the saturated zone was

determined by two different methods:


1. The computer model INVERS assigned resistivity

values to the geoelectric layer representing the zone of

saturation within the constraints of the fixed parameters

associated with geological control data.

2. Specific conductance values of domestic well water were

combined with Archie's Law, to determine reasonable aquifer

resistivities for some of the sand-gravel units.

In addition to chloride, water samples from domestic wells

were also tested for specific conductance. Specific conductance

values were converted to resistivity values and were then applied

to Archie's Law. Archie's Law can be written as follows:

^FMN " H2(/0 ^where “ formation resistivity, ^ 2 0 “ resistivity of the

interstitial water, i6 - porosity, m - matrix cementation factor.

Calculation of Archie's Law resulted in determining the average

aquifer formation resistivity from the depths at which the

domestic wells were screened. Archie's Law calculations can be

found in Appendix D.

Porosity values of glacial materials can vary greatly. Most

porosity values of unsorted tills would be expected to fall within

the range of 25 to 45%, with the higher values representing the

clay-rich till (Davis & DeWiest, 1966). The value of 30%, used in

Archie's Law in this study, typically represents clean sands and

gravels, such as those composing the drift aquifer in the study

area. Kwader (1985) points out that matrix cementation factors

for most unconsolidated quartz sand aquifers range from


1.3 to 1.4. For this study a value of 1.35 was used, to represent

the matrix cementation factor.

Eorosity, as with water quality, is not expected to remain

constant across a given geoelectric section. The formation

resistivity values calculated from Archies's Law were used as

estimates only. These values were, therefore, allowed to

fluctuate when no control data were available.

It is possible that the water quality data collected from

sampling these wells may not be representative of the actual

groundwater quality of the aquifer. Some of the well screens are

completed partly into the contamination zone and partly into the

overlying fresh water zone. It is likely, therefore, that the

specific conductance data collected from water samples are lower

than that of the actual groundwater quality. The resistivity

values calculated from Archie's Law may represent the maximum

resistivity and thickness values for this low resistivity zone.

The INVERS-generated resistivity values are much lower than those

derived from Archie's Law, and may describe the minimum

resistivity and thickness values for this layer. The real

resistivity and thickness values are unknown, and may lie between

values described by these two models.

Three geoelectric sections are described in the

Interpretation of Field Data Section. Model A represents computer

generated resistivity values of the saturated zone, and Model B

represents the same geoelectric section calculated by INVERS, but

with the aquifer resistivity constrained to the value calculated


from Archie's Law, based on water conductivity assumed porosity of

30%, and cementation factor of 1.35.

Geoelectric Section A

Geoelectric Section A is based on eight vertical electrical

soundings (VES's), one water well record, one soil boring and two

oil well records (Plate 1). Both models A and B show several

distinct geoelectric layers. The first layer below ground level

is characterized by interpreted resistivity values that range from

about 75 to 1400 ohm-raeters. These heterogeneous surficial

materials are interfingered with unsaturated sands.

Below the surficial materials lies a clay unit in both

models. Model A shows that the layer appears to thicken from

about 0.6 meters (two feet) at VES #1 to nearly 12 meters (40

feet) at VES #3b, and is represented by interpreted resistivity

values of 11 to 65 ohm-raeters. In Model B the clay-rich zone is

very thin, ranging from 0.6 to about 3 meters (2 to 10 feet), and

is characterized by interpreted values of 21 to 96 ohm-meters.

True resistivity values of 48 to 68 ohm-meters were noted in the

laboratory. Below this point in the geoelectric section the two

models have few similarities and will, therefore, be described

individually.

In Model A a water-bearing sand and gravel unit exists

beneath the clay-rich unit. It is denoted by interpreted

resistivity values of from 19 to 700 ohm-meters, with resistivity

values of 80 ohm-meters or less denoting isolated clay-bearing


zones. Static water level data indicate that this sand and gravel

unit represents a portion of both the unsaturated and the

saturated zones. Laboratory values of 45 and 68 ohm-meters

describe the sand and gravel materials. The soil boring and the

domestic well completed in this zone were sampled and tested for

chlorides, showing levels of 50 and 75 mg/L, respectively. These

are of background chloride levels, not indicative of groundwater

degradation.

Low interpreted resistivity values, ranging from 8 to 16 ohm-

meters define the resistivity layer underlying the sand and gravel

unit. This layer averages about 8 meters (25 feet) in thickness.

No water quality data, or detailed geological or geophysical

information, were available to describe this geoelectric layer, or

those underlying it. The low interpreted resistivity values of

this layer suggest that it represents either a clay-rich layer, or

perhaps a zone of groundwater contamination. Better control data

are needed in order to make this distinction.

This conductive layer is continuous across most of the

section except at VES #3B. At VES #3B no geoelectric layers are

detected at a depth greater than that of the sand and gravel

unit. The reason that these deeper layers are not detected may be

the result of only a shallow depth of electrical current

penetration, when employing the surface resistivity method, caused

by the thick low resistivity layer above. Alternately, the low

resistivity layer underlying the shallow clay might not be


continuous to the northwest, and it might not exist beneath

sounding #3b.

Underlying the deep low resistivity layer is a unit with

interpreted resistivities that vary from 151 to 440 ohm-meters. It

is continuous from VES #1 to #3A. Well record data from oil

wells located about 50 meters (164 feet) southeast of VES #1

suggest that bedrock in the vicinity of Geoelectric Section A may

be detected within this deepest resistivity layer. This

geoelectric layer may presumably describe either the top of the

Michigan shale and limestone, or the deepest portion of the

glacial overburden above the bedrock. Based on similar

resistivity values between this deepest geoelectric layer and the

layer below the shallow clay unit, this layer likely depicts sand

and gravel glacial materials.

In Model B a sandy-clay zone is detected below the clay-rich

zone. Geological control data indicate that this geoelectric

layer is made up of unsaturated sands and clays. Interpreted

resistivity values range from 117 to 291 ohm-meters. Laboratory

values from SB #4 show true resistivity values ranging from 48 to

200 ohm-meters.

Beneath the sand and clay unit lies a geoelectric layer

represented by interpreted resistivity values of 57 to 82 ohm-

meters between VES #3B and 3', and 31 to 36 ohm-meters between VES

#2B and IB. No control data are available to define the north

western portion of this layer. Soil boring #4, completed in the

low resistivity portion of this geoelectric layer, indicates that


at least the upper portion is composed o£ saturated sand and

gravel. True resistivity values were calculated to be 45 to 48

ohm-meters. A water sample detected 50 mg/L chloride, which is

within the inferred background chloride level. These data do not

support that the upper portion of this low resistivity zone

represents a zone of groundwater degradation. Additional

geological and water quality data would be needed in order to make

any conclusions about this layer.

No geological, water quality or lab data were available to

describe geoelectric layers underlying the low resistivity layer

mentioned above. Only inferences can be made with regard to the

nature of these layers. The geoelectric layer underlying the low

resistivity layer varies from 108 to 305 ohm-meters. At VES #1A

neither the low resistivity zone mentioned above nor this

relatively high resistivity zone are detected. One medium

interpreted resistivity value of 74 ohm-meters has been assigned

to represent approximately 27 meters (90 feet) of rock material.

This resistivity value and thickness are anomalous and do not fit

the model. It is inferred that the overlying low resistivity

layer and the relatively high resistivity layer are being

represented by one medium resistivity value.

One high interpreted resistivity value of 630 ohm-meters was

noted below the above-mentioned zone at VES #1 and a value of 91

ohm-meters was detected at VES 3'. These geoelectric layers

likely define the bedrock surface, describing the limestone and

the sandy shale members of the Michigan Formation, respectively.


Geoelectric Section D

Ten soundings were correlated with six water well records,

three oil well records and one soil boring record in Geoelectric

Section D (Plate 2). Both Model A and Model B similarly

characterize five geoelectric layers, while only three different

geological units may in fact exist. At the surface are several

thin discontinuous geoelectric layers denoted by interpreted

resistivity values that range from 84 to 2796 ohm-meters. These

layers represents heterogeneous surficial materials.

Below the surface layer is a clay-rich unit interspersed with

sand and gravel. This clay-rich unit is characterized by low

values of interpreted resistivity, varying from 7 to 77 ohm-

raeters, and is laterally continuous across the section.

Calculated true resistivity values for sandy clay materials range

from 185 to 244 ohm-meters; clay is characterized by a value of 41

ohm-raeters. An anomalously low value of interpreted resistivity

within this clay-rich unit is detected at VES #48. The

significance of this low resistivity layer is unknown due to

inadequate geological control.

Underlying the clay-rich unit is a sand and gravel unit

intercalated with clay. The sand and gravel unit appears to be

subdivided into three distinct geoelectric layers. The first of

these layers can be described as a clay-rich sand unit. Static

water level data suggest that this unit encompasses both the

unsaturated and the saturated zones. Interpreted resistivity


values range from 100 to 660 ohm-meters. True resistivity values

range from 89 ohm-meters, to 954 ohm-meters. Two domestic wells

and one soil boring were completed i n this zone. Chloride levels

detected in water samples from the wells were 113 and 165 mg/L,

somewhat higher than the supposed background level. No water

samples were collected from SB #3.

Beneath the clay-rich sand unit is a geoelectric layer

characterized by low interpreted resistivity values. These values

range from 4 to 32 ohm-meters in Model A, from 22 to 53 ohm-meters

in Model B. This geoelectric layer is about 396 meters (1300

feet) in length, and averages approximately 4 meters (12 feet) in

thickness in Model A, and 14 meters (45 feet) in Model B. It is

described as a sand and gravel unit in the log of oil well #9851,

as it is in the logs of three o f the domestic wells. Water

samples from the domestic wells that are at least partially

screened in this low resistivity zone, demonstrate elevated levels

of chloride, ranging from 352 to 515 mg/L. From these data it is

inferred that this geoelectric unit represents a zone of

groundwater contamination.

The proposed plume within the sand and gravel unit is not

detected at VES #49 in either of t h e two models. Two possible

reasons for its absence are as follows: (1) this low resistivity

layer may not be detected by surface electrical resistivity due to

the thick overlying clay at VES #49, which would allow only for a

shallow depth of current penetration, or (2) simply that this

layer does not extend laterally this far to the northwest.


At VES #12 only the upper boundary of the inferred plume is

detected. The lower boundary is interpolated from adjacent

soundings. Relatively higher resistivity values were observed

within this zone at VES #11 and #12. Insufficient geological data

exist to interpret these values. Perhaps the concentration of

dissolved solids is lower in the vicinity of these soundings.

Underlying the inferred plume is a geoelectric layer

characterized by interpreted resistivity values of from 125 to 300

ohm-meters. In Model A it is described by the well log for oil

well #9851 as sand and gravel. No geological data are available to

correlate with these depths in Model B. None of the soundings

delineated the bedrock surface.

Geoelectric Section E

Geoelectric Section E was prepared using twelve vertical

electrical soundings that are correlated with three well records

and one soil boring (Plate 3). Five geoelectric layers are

interpreted in both Model A and B, while only three principal

geological units likely exist. Values of interpreted resistivity

were similarly assigned in both models to all but the deepest

conductive layer. The discrepancy in layer thickness and

interpreted resistivity values between the two models of this

layer is a function of the method of interpretation (see Types of

Electrode Configurations).


The near surface resistivity layer is heterogeneous in

nature. Below it lies a layer that is characterized by low values

of interpreted resistivity, varying from 15 to 88 ohm-meters. It

is continuous across the section and thickens toward the middle of

the section. The accompanying geological data indicate that this

is a moist sand and clay unit. True resistivity values of from 28

to 51 ohm-meters were calculated for this unit.

Beneath the sand and clay unit two geoelectric layers are

detected which constitute one geological unit, a clay-bearing

gravel and sand. The first of these two layers is relatively

thick and continuous across the section. Interpreted resistivity

values ranging from 100 to 998 ohm-meters define this layer. True

resistivities were computed as follows: clay - 31 ohm-meters; dry

sand - 978 to 2212 ohm-meters; moist to saturated sand - 46 to 86

ohm-raeters. Static water level information suggest that this

layer represents the lower region of the vadose zone, and the

upper portion of the phreatic zone. A soil boring was completed

in this zone. No water quality data were available from this

boring.

Within this zone low values of interpreted resistivity of 100

to 140 ohm-meters were detected near VES #31, and #24 through #26

in both Models A and B. These relatively low values may be

interpreted as suggesting a localized increase in clay content of

the gravel and sand materials. It can also be inferred from the

low interpreted resistivity values that this interval depicts

groundwater contamination.


The second of the two resistivity layers representing this

same gravel and sand unit is described by anomalously low

resistivity values, varying from 7 to 22 ohm-meters in Model A,

and 15 to 83 ohm-meters in Model B. This layer exists

approximately 9 meters (30 feet) below the potentiometric surface

and is at least 366 meters 1200 feet in length. It averages about

6 meters (18 feet) in thickness in Model A and about 12 meters

(40 feet) in thickness in Model B. It is fairly uniform in

thickness in Model A, but seems to pinch out to the southeast

between VES #26 and #27. In Model B the thickness of this layer

varies greatly across the geoelectric section. These low modeled

resistivity values for the sand and gravel unit appear to

characterize groundwater contamination. Two domestic wells within

this zone tested for chloride showed levels of 411 and 722 mg/L.

These levels are far above background chloride levels, lending

support to the possibility of a contamination plume.

At VES #27 through #29 resistivity values range from 66 to

125 ohm-meters in both Model A and B. This portion of the sand

and gravel unit apparently has not been impacted by chloride

contamination (Figure 15) or else the impact has been minimal.

Lower chloride values of 138 mg/L detected from sampling a nearby

domestic well support this suggestion.

Underlying the inferred contamination plume is the last

resistivity layer indicated by surface geophysical methods in this

section. No geological data are available to describe this lower

layer, which has values of interpreted resistivity ranging from


100 to 375 ohm-raeters. It is possible that this deepest

resistivity layer detected actually portrays the lower zone of the

same sand and gravel unit that contains the inferred contamination

plume. Interpreted resistivity values of this unit are similar to

those of Geoelectric Section D, which was run parallel to this

section. In Geoelectric Section D geological data were available

which showed that the deepest resistivity layer was the same

aquifer material as that above the inferred contamination plume.

No data were available for bedrock depth in this section.

Longitudinal Conductance Map

As described in the third stage of the data reduction

section, longitudinal conductance (S), is expressed as

S = ^ h^/ f , where h^ = the sum of the thickness of the

geoelectric layers, and f = the sum of the interpreted

resistivity of the geoelectric layers of a. given VES (see

Electrical Resistivity). The map of longitudinal conductance was

created by adding together all the longitudinal conductance values

at each vertical electrical sounding. The summed S values are a

good indicator of the total amount of conductive material

investigated by a VES, and are independent of any particular

subsurface interpretive model. The INVERS computer modeling

program computes the S values of each geoelectric layer, as well

as other parameters (Appendix C). The S values for all

geoelectric layers at each VES were added and plotted at the


respective VES stations (Figure 20). These values were then

contoured at 0.2 mho increments (Figure 25).

All fifty five of the S values were plotted. VES #31,

however, represents an anomalous value of S. At VES #31 the S

value is calculated as 0.085 mhos. Values from several nearby

data points range from 1.10 to 1.38 mhos. Since this value is

inconsistent with five surrounding data points, the author has

chosen to ignore this data point with regard to contouring the

map of longitudinal conductance (Figure 25). The cause of this

relatively low S value appears to be related to the thinner nature

of the inferred groundwater contamination plume at VES #31.

S values from within the study area ranged from 0.04 to 2.19

mhos. High values of S correspond to low values of interpreted

resistivity. This map roughly defines four such zones. Three

high longitudinal conductance zones are located along Geoelectric

Sections C, D, E, and F, and roughly trend S-SW. Another high

longitudinal conductance zone lies along Geoelectrical Section A,

and it trends W-NW (Figure 16). The contamination plumes depicted

in the chloride and specific conductance water quality maps

generally correspond with the zones of high S values in the

southwest portion of the study area (Figures 14 and 15). This

correlation between water quality and geophysical data support the

possibility of these zones representing localized groundwater

contamination.


The highly conductive area intersecting 14th Street supports

a localized north-westward groundwater flow direction in this

area, related to the inferred groundwater divide. It is

depicted uniquely on this map. Further study should be

conducted in this area to verify the existance of this zone and to

determine its significance.

Lab Procedures

Several soil samples, collected with the split spoon sampler

from the soil borings, were lab-tested for resistivity.

Resistivity was calculated by measuring the length and diameter of

the soil sample and by measuring the current and the voltage.

Clay soil samples, being cohesive in nature, retained the

cylindrical shape of the sampling device. The unconsolidated sand

and gravels were packed into a small glass beaker before the

resistivity value could be calculated. Four wire screens were

used as AB and MN electrodes (Figure 26).

S

01 L

I________

Figure 26. Arrangement of Sheet Electrodes Used in Laboratory Analysis of Soil Samples.

<3

<8>


Resistivity in the laboratory was calculated by using the

following equation: / - (V/I)*(A/L). The resistivity calculated

in the laboratory approximates the true resistivity, and any

differences arising from sample disturbance between the time of

collection and the time of laboratory measurements. This is true

because the sample was measured and the current distribution was

controlled.

Soil samples may have lost moisture during their storage

period in the laboratory. In order to compensate for this loss,

those samples that were considered moist or wet during sample

collection were checked before laboratory analysis. If necessary

they were saturated with deionized water and were retested.

Lab-calculated true resistivity values were used to aid in

interpretation of apparent resistivity field data and the

geoelectric sections. See Appendix B for laboratory calculated

values of true resistivity.


CONCLUSIONS AND RECOMMENDATIONS

1. The surface electrical resistivity survey successfully

defined zones of groundwater contamination of a drift aquifer

within the study area. The shape of the plumes, and the lateral

and vertical margins were delineated.

2. Also identified by the electrical resistivity survey was

a conductive zone in the northeastern portion of the study area.

The significance of this zone is not clear, however, as there

were no geological data available for this portion of the study

area.

3. In general five geoelectric layers were detected in

several of the geoelectric sections. A heterogeneous dry sand

material is inferred to exist at the surface in the study area.

Interpreted resistivity values for this zone ranged from 60 to

3000 ohm-meters.

(a) A moist to dry clay was detected below the surficial

materials, with interpreted resistivity values varying from about

7 to 85 ohm-meters.

(b) A sand and gravel zone was identified below the clay

material. It appears that one interpreted resistivity range

from 100 to 1000 ohm-meters characterizes both the lower portion

of the unsaturated zone and the upper portion of the saturated

zone.

(c) A low resistivity layer was detected within the sand and

gravel aquifer in several geoelectric sections. It is

81


characterized by interpreted resistivity values that vary from

about 4 to 85 ohm-meters. Water quality data from domestic wells

and geological data from soil boring logs, water and oil well

records, all indicate that this zone is a brine contamination

plume.

(d) Below the brine plume, very little if any water quality,

geophysical or geological data were available for correlation

with the geoelectric layers. Interpreted resistivity values

ranged from 60 to 600 ohm-meters. The bedrock surface was not

clearly defined in the geoelectric sections.

4. In general employing this geophysical technique allowed

for detecting geoelectric layers to about 30 meters (100 feet)

below ground level, or approximately 1/10 the AB/2 separation.

In a few vertical electrical soundings, however, thick clay

layers located near the surface prevented the detection of

underlying geoelectric layers. Relatively deeply buried

geoelectric layers were not identified in these instances because

the electrical current introduced at the surface was not able to

penetrate deep enough into the subsurface to detect the

conductive zone below the water table.

5. In conducting the surface electrical resistivity survey,

many problems and inconveniences were encountered due to cultural

factors. These cultural factors often acted to limit the maximum

expansion of the electrode array and distort a few of the

apparent resistivity sounding curves (VES #3) for example.


83

6. Two different interpretational models were constructed

for each of Geoelectric Sections A, D and E. The first, allowing

more freedom for program INVERS, resulted in very low

resistivities and small thickness values for much of the aquifer

layer (Model A). In the second case the aquifer resistivities

were constrained to higher values compatible with the measured

water resistivities s calculated by Archie's Law, holding $ =

30%, and cementation factor (ra) - 1.35 (Model B). This resulted

in greater thickness for the aquifer layer. Both solutions are

geophysically correct, by the principle of equivalence, and only

independent thickness or in situ resistivity data could constrain

the solution.

7. It is recommended that a few small diameter wells be

completed in the highly conductive zone located in the

northeastern portion of the study area. This would allow for

obtaining geological and water quality data that can be used to

correlate with the geophysical data, in order to determine if the

zone represents a groundwater contamination plume, perhaps, a

clay-rich layer.

8. It is recommended that soil borings be drilled to depths

sufficient to penetrate all units of possible interest in the

problem area, commensurate with the depth of investigation of the

VES's. In this case they should have been approximately twice as

deep, in the range of 30 to 37 meters (100-120 feet), so that the

calibrated VES done at the same location could have all main

layer thicknesses constrained.


9. Even better for calibrating the VES's at control

boreholes would be an open-hole resistivity log which should give

the geoelectric layer boundaries and their resistivities, thus

constraining very well the calibration VES. If a natural gamma

log were available, it also would help to define the contacts

between clay and coarser clastic units and give an independent

check of the drilling record.

10. Further surface electrical resistivity work at this site

should be geared toward determining lateral, particularly

downstream, limits of the plume. The contour maps shown here

have the contours rather arbitrarily closed, particularly at the

distal "ends" of the plume.


APPENDICES

85


Appendix A

Equipment

86


Equipment

Several different pieces of equipment were used in conducting

the surface electrical resistivity study, among which were the

following:

IC - 69 Earth Resistivity Meter (Figure 27)

external battery pack

current and potential electrodes

approximately 350 meters (107 feet)

of insulated wire

leads, and wire reels

two-way radios

miscellaneous equipment

IC-69 Earth Resistivity Meter (Johnson Keck)

microammeter

range switch

current switch

ohmmeter dial

:0— Q -

••-

-v

external battery pack attachment

electrode attachment

null meter

self potential dial

Figure 27. Sketch of IC-69 Earth Resistivity Meter.


microammeter - measures the amount of current generated; tests the

strength of some of the internal batteries.

range switch - decimal multiplier of the resistance readings from

the ohmmeter dial.

current switch - induces an electrical current into the ground

through current electrodes; FORWARD and REVERSE positions allow

the direction of the current to alternate between the electrodes.

ohmmeter dial - yields the resistance value (ohms) of a given

reading when multiplied by the range switch value.

external battery pack attachments - point of cable attachment to

the external batteries; employed when the current electrode

contact resistance was very high.

electrode attachments - point of attachment of wire leads from

from the current and potential electrodes to the instrument

terminals.

null meter - microammeter used in taking resistance readings.

self-potential dial - nulls out the electrochemical activity

between electrodes and the surrounding soils.

external battery pack - adds 10 45-volt batteries to the four

internal 45-volt battery supply; these supplemental batteries can

be added to the power supply one at a time.

current and potential electrodes - used to induce electrical

current into the ground and to measure the voltage drop,

respectively; current electrodes are made up of two 1/2-inch by

60 inch steel rods. Potential electrodes consist of 1-inch x 18

inch hollow PVC stakes; each stake contains copper sulfate that is


in contact with the surrounding soils through the porous wooden

stake tips. These non-polarizing electrodes virtually eliminate

electrode-generated potentials that could occur between

electrodes.

two reels with about 320 meters (1050 feet) of wire each, two reels 35 meters (115 feet) of wire; wire leads; - used to expand

the distance between electrodes, allowing for a variety of AB/2

and MN spacings; two wooden and two small plastic reels were used

to facilitate the carrying and dispensing of varying amounts of

wire to both AB and MN electrodes.

two - way radios - three radios were used to facilitate

communication between the operator of the IC-69 equipment and the

field crew at large AB/2 spacings.

miscellaneous equipment - several different tools were kept on

hand for minor repairs, clean up and storage of the equipment.

These included Allen wrenches, screw drivers, extra wire, metal

brushes, metal tape, tape measure, metal stakes, metal clips, data

forms, calculator, and graph paper; also hammers and salt water

were carried into the field to increase current by reducing the

resistivity of the ground surrounding the electrodes, thereby

making better contact with the electrodes when necessary.

These equipment were used for the two consecutive summers of

1982/83. Western Michigan University's IC-69 unit was used

through out the majority of the survey. However, a Keck unit was

loaned to us when the other unit malfunctioned, as noted on the

data sheets.


Appendix B

Soil Boring Data and Laboratory Results

90


91

Soil Boring and Laboratory Results_____ Soil Boring #1 - Wagner____

Geological Sampling Laboratory-ProducedDescription___________ Interval Resistivity Results

brown clay 3.5 - 5'f = 6 7 ~ A ~ • m

= 625 m

brown clay gray clay w/ gravel 8.5 - 10'

? = 4 8 _n_ • m y > l S - 204 _/!.• m

moist.brown and gray clay w/ sand .lenses

13.5 - 15' y = 144 ~n.- m

18.5 - 20' = 145 _o.. mwet brown sand

brown sand with some gravel

23.5 - 25's = 589 m

y = 1249 - A . ■ ra

28.5 - 30' " f ^ = 1435 -/!• m

33.5 - 35' * 387 s i . - m = 1034 _/L • m

wet gravel and sand 38.5 - 40' y =165 m

• tg ■ true resistivity of lab-saturated material

= true resistivity of material as collected in field


92

Soil Boring and Laboratory Results_____ Soil Boring #2 - Church_____

Geological Sampling Laboratory-ProducedDescription__________ Interval Resistivity Results

moist sandy brown and gray clay w/ cobbles 3.5 - 5' Y t = 39 -4.. m

moist soft sandy gray clay w/ some

gravel 8.5 - 10' E00CMnV*

13.5 - 15 / = 29 ~ n ~ • m t

moist stiff gray clay w/ some sand 18.5 - 19

19.0 - 20= 51 -J2. • m

/ = 1865 -A • m

dry brown sand 23.5 -25' y = 978 J L . - m

gray silty clay

28.5 - 30' Y t = 31 _/z. • m

33.5 - 35' f t = 2212 _o_- m

brown clay/dry brown sand

moist brown sand 38.5 - 40' = 46 . / i - m

wet brown sand 43.5 - 45' Y t = 8 6 ^ L - m

= true resistivity of material as collected in field


93

Soil Boring and Laboratory Results_____ Soil Boring #3 - Quick_____

GeologicalDescription

SamplingInterval

Laboratory-Eroduced Resistivity Results

stiff brown sandy clay w/ some cobbles 3.5 - 5' f = 244 J L ' ra

soft sandy brown and gray clay w/ some

coarse sand8.5 - 10' / = 185 -A-' m

13.5 - 15' y = 238 Ji. • mmoist brown sand t

brown sandy clay w/ gravel 18.5 - 20'

insufficientsample

stiff gray clay w/ some sand

23.5 - 25' y - 4 1 -A-* m

and gravel28.5 - 30' / = 383 _/L* m

brown and gray sand33.5 - 35' Y - 954 _/!. • m

wet brown and gray fine sand 38.5 - 40' y = 8 9 - A - ' m

/ = true resistivity of material as collected in field


94

Soil Boring and Laboratory Results- Soil BorinR #4 - Ellis_____

Geological Sampling Laboratory-Produced0 Description___________ Interval Resistivity Results

red and brown sandy clay

3.5 - 5' ^ = 200 — 0. • ni

8.5 - 10' u •p* 00 3moist red clay w/ gravel

moist sandy clay 13.5 - 15' ^ = 6 0 _/!_• m

stiff gray clay w/ some gravel 18.5 - 20' = 53 —£-• m

stiff gray clay w/ interbedded

sands 23.5 - 35' y = 68 — m

28.5 - 30' = 45 —ri- • rnwet gray and brown sand

sample not returned 33.5 - 35' --

wet gray and brown sand and gravel 38.5 - 40' y = 48 — A • n

y' = true resistivity of material as collected in field


Appendix C

Apparent Resistivity Data

95


96

ITERATION NO. 15, VES NO. 1LATER THICKNESS ELEV RHO THICKSRES THICK/RES1 1.44 677.0 573.5 823.0 0.00252 0.33 672.3 11.0 9.1 0.07563 4.37 669.5 242.9 1061.0 0.0180"4 2.04 655.2 24.0 48.8 0.08505 • 8.12 648.5 390.0 3165.6 . 0.02086 3.79 621.9 16.0 60.6 0.2367.. 7 . 609.5 440.0 • ■"'Tirp’v.

SPACING MODEL RHO FIELD RHO1.00 539.8 534.01-47 ___ 485.7 ..517,0 _

2.15 379.2 357.03.16 233.4 232.04.64 116.1 118.06.81 74.9 77.210.00 80.7 77.014.68 95.2 93.621.54 108.1 111.031.62 120.2 115.046.42 132.8 135.068.13 143.3 156.0100.00 173.1 158.0146.73 210.9 223.0RMS ERROR = 4.613

ITERATION NO. 15, VES NO. 1ALATER. 1 .• 2

3 ...•= . 4 . • • 567 .

THICKNESS ELEV0.662.023.961*967.987.60.

679.0676.8670.2657.2650.8624.6599.7

RHO65.217.3158.0 18.9411.0 9.0151.2

THICK*RES43.3 34.9625.537.03280.668.4

THICK/RES0.01020.11640.02510.10340.01940.8447

SPACING 1.00 v 1.47 2.15, 3.16 4.64 6.81 10.00

1.4..6 Ju.

MODEL RHO50.739.429.827.0 , 31.440.251.0 62.1

FIELD RHO50.639.4 29.926.632.439.549.565.5

2 1 . 5 431.6246.4268.13100.001 4 6 . 7 8

I ?-383.890.690.386.087.0

71.4 82.692.490.8 84.687.8RMS ERROR a 2.201


97

ITERATION NO. 15# VES NO. IBLAYER

1234 S'

THICKNESS ELEV1.942.587.419.72

SPACING-l.OO.

678.0 671.7 663.2638.9607.0V 'V.MODEL RHO110.9

RHO THICKCRES 111.8 216.455.0 141.8700.1 5139.78.0 77.4216.0 - •

THICK/RES0.01730.04690.01061.2214

>.15 09 a i 05.!

i o : S o : ‘ ill:14*68 156.121.54 •; • 179.!111 •46.42 '■■■. ! 15 2 • 6;;~-~r t no-

FIELD RHO113. C11:1 '97.4

V -"'4 v, •■•V

life:.:

, 68.13m-r* 108.2y 100.00 -v- 79.8 ;RMS ERROR = • 3.516

192.9 *

...

1:8h i . •

ITERATION NO. 15* VES NO. 2IYER THICKNESS ELEV RHO THICKfrRES1 0.37 680.0 1100.0 409.92 1.67 678.8 134.1 224.33 0.98 673.3 10.9 10.74 10.51 670.1 152.1 1598.85 5.59 635.6 16.0 89.46 617.3 243.0

SPACING HOOEL RHO FIELD RHO1.00 388.8 408.01.47 210.0 202.62.15 131.1 124.83.16 91.9 92.84.64 64.3 69.06.81 55.2 50.010.00 62.6 55.414.63 74.4 83.021.54 83.1 100.031.62 36.5 34.646.42 89.0 74.363.13 99.0 104.3100.00 119.5 125.6

THICK/RES0.00030.01250.08920.06910.3492

RMS ERROR = 9.717


ITERATION NO- 15, VES NO. 2aLAYER THICKNESS ELEV RHO THICK*RES1 1-59 . 682-0 238-0 377.52 3.33 676.8 39.0 129.83 7.12 665-9 510-0 3623.74 8.10 642.5 8.0 64.75 616.0 200.0

SPACING MODEL1RHO FIELD RHO1.00 229.6 219.01.47 215.5 222.02.15 185.4 190.03.16 139.1 142.04.64 95.2 93.06.81 73.0 76.610.00 38.4 87.714.63 109.3 109.021.54 127.5 1 25.031.62 130.7 136.046.42 114.9 122.068.13 90.5 87.4100.00 • 73.5 72.1146.73 87.2 94.5RMS ERROR = 4.233

ITERATION NO. 15, VES NO. 28LAYER

1 2. 345

THICKNESS ELEV0.99 683.0 RHO234.74.82 679.8 45.7- 11.27 663.9 300.49.09 . 627.0 9.0597.1 263.6

SPACING MODEL RHO FIELD RHO1.00 208.4 225.01.47 175.5 163.02.15 128.0 121.03.16 84.5 91.54.64 63.0 62.86.81 62.2 60.210.00 73.8 70.414.63 91.6 95.221.54 103.3 112.031.62 115.3 114.046.42 107.4 103.068.13 90.6 90.1100.00 32.4 31.5146.73______93.3 ______94.J5__

RMS ERROR = 4.400

THICK*RES 232.5 220.2 3384.1 81.8

THICK/RES0.00670.03530.01401.0130

THICK/RES0.00420.1056-0.03751.0100\


99

• vITERATION NO. 15, VES NO. 3 LATER THICKNESS ELEV RHO

1231.322.55 680.0675.7667.3

1582.420.0100.2

THICKSRES2033.750.9

SPACING1.001.472.153.16 4.64 6.8110.0014.6321.54

MODEL RHO 1459.9 1272.2925.6490.7 171.157.949.459.4 70.2

FIELD RHO1382.01461.0983.0485.0171.0 55.0 47.6 63.5 71.4RMS ERROR = 5.962

ITERATION NO. 15* VES NO. 3*LAYER THICKNESS ELEV RHO THICK*RES1 0.30 683.0 498.0 143.72 0.99 682.0 1787.0 1762.23 5.02 673.8 26.0 130.44 12.41 662.3 164.9 2046.35 8.29 621.6 9.8 81.36 594.4 171.0

SPACING MODEL RHO FIELD RHO1.00 393.7 908.01.47 973.1 997.02.15 918.7 987.03.16 681.5 703.04.64 359.3 342.06.81 130.2 133.010.00 55.0 56.314.63 53.5 54.721.54 63.6 62.831.62 70.6 67.946.42 71.3 \ 72.168.13 63.6 X 69.7100.00 71.0 \ 72.1146.78 82.8 . . 81.0RMS ERROR = 2.619

THICK/RES0.00030.1273

THICK/RES0.00060.00060.19290.07530.8452


100

ITERATION NO. 3, VES NO. 3ALAYER THICKNESS ELEV RHO THICKSRES THICK/RES1 0.13 633.0 136.0 17.8 0.00102 0.98 682.6 1100.0 1081.6 0.00093 6.42 679.3 30.0 192.9 0.21404 11.51 658.3 80.0 920.8 . 0.14395 11.01 620.5 14.0 154.1 ' 0.78626 584.4 276.0

SPACING MOOEL RHO FIELD RHO1.00 . 534.8 502.01.47 586.2 575.02.15 552.5 551.03.16 413.1 463.04.64 224.9 239.06.81 91.1 81.710.00 45.7 45.514.68 42.7 42.721.54 46.7 47.231.62 49.3 50.046.42 50.7 50.268.13 56.3 56.0

100.00 70.4 68.9146.78 92.3 94. 5

RMS ERROR = 4. 970

ITERATION NO. 15. VES NO. 38 LAYER.. THICKNESS... ELEV RHO THICKSRES THICK/RES

1 0.05 633.0 60.52 0.69 632.3 1000.03 1.99 630.6 320.04 11.33 674.0 24.05 635.2 177.0

SPACING MODEL RHO FIELD RHO1.00 550.7 509.01.47 583.3 618.02.15 543.2 . 550.03.16 430.5 478.04.64 280.2 270.06.81 142.6 126.010.00 60.6 60.114.68 36.2 46.6. 21.54 38.6 43.231.62 49.6 47.046.42 64.9 56.368.13 83.0 75.1100.00 102.6 97.2146.78 122.0 122.0

2.9638.7637.8 2 33.9

0.00030.00070.00620.4928

RHS ERROR = 10.964


101

ITERATION NO. 15, VES NO. 4LAYER THICKNESS ELEV RHO THICK*R£S1 1.41 685.0 215.7 304.22 6.05 680.4 38.3 231.63 5.70 660.5 403.0 2298.84 5.59 641.8 16.7 93.35 623.5 119.1

SPACING MODEL RHO FIELD RHO1.00 205.4 207.01.47 189.0 194.02.15 156.4 153.03.16 111.1 106.04.64 71.3 75.46.31 54.6 55.510.00 56.5 53.214.63 68.2 65.521.54 . 82.2 36.731.62 92.0 97.246.42 94.7 94.668.13 93.4 97.4100.00 94.4 92.6146.78 99.9 107.0RMS ERROR = 4.357

ITERATION NO. 1* VES NO. 5

THICK/RES0.00650.15900 . 0 1 4 20.3349

LAYER THICKNESS ELEV 1 0.61 688.02 1.70 . 686.03 1.30 680.44 , 12.40 676.25' 635.5

RHO73.925.0199.0854.040.0

THICKSRES45.142.5258.710539.6

THICK/RES0.00330.06300.00650.0145\

\SPACING 1.00 1.472.153.16 4.64 6.8110.001 4 . 6 321.5431.6246.4268.13100.00

MODEL RHO57.746.939.942.054.375.6105.2142.6184.2220.4234.1209.7151.1

FIELD RHO60.048.233.039.152.377.3105.0140.0137.0230.0230.0197.0135.0RMS ERROR = 5.057


102

ITERATION NO. 15. VES NO. 6LATER THICKNESS ELEV RHO THICK*RES

1 0 . 5 8 6 3 5 . 0 5 5 8 . 9 3 2 2 . 92 0 . 8 8 6 8 3 . 1 5 0 . 0 4 A . 0

•.•3. , . • 4 . 5 8 6 8 0 . 2 . 2 0 0 . 9 9 2 0 . 4. 4 - . 1 3 . 5 5 : 6 6 5 . 2 6 7 6 . 0 9 1 6 2 . 3

s 5 : 6 2 0 . 7 1 7 4 . 7

THICK/RES0.00100 . 0 1 7 60 . 0 2 2 8 -0.0200

SPACING > MOOEL RHO FIELD RHO1 . 0 0 3 4 0 . 5 3 3 2 . 01 . 4 7 2 1 0 . 4 2 3 5 . 0

. 2 . 1 5 . 1 2 7 . 3 . 1 1 2 . 03 . 1 6 1 1 2 . 7 1 1 0 . 04 . 6 4 , . 1 3 2 . 3 ... 1 3 4 . 06 . 8 1 \ 1 6 2 . 5 1 7 0 . 0

1 0 . 0 0 2 0 1 . 3 - ... 2 1 5 . 01 4 . 6 8 ' 2 4 9 . 4 2 5 3 . 02 1 . 5 4 2 9 9 . 3 2 9 7 . 03 1 . 6 2 3 3 4 . 0 3 0 8 . 04 6 . 4 2 3 3 5 . 0 3 1 3 . 0 ,6 3 . 1 3 2 9 8 . 7 2 9 7 . 0

1 0 0 . 0 0 2 4 6 . 5 2 6 0 . 01 4 6 . 7 8 2 0 6 . 6 2 2 3 . 0

RMS ERROR = 6 . 4 1 6

ITERATION NO. 11, VES NO. 9LAYER THIC KNE3S ELEV RHO TH1 1.31 690.0 71 3.92 0.77 635.7 9.03 11.34 633.2 1100.64 4.67 646.0 s . a5 630.6 346.1

SPACING MODEL RHO FIELD RHO1.00 663.9 635.01.47 530.1 550.02.15 426. S 414.03.16 239.0 263.04.64 110.3 105.06.31 30.1 77.010.00 102.2 97.014.68 133.7 130.021.54 133.6 175.031.62 225.4 242.046.42 250.6 304.063.13 245.5 279.0100.00 214.5 132.0146.78 137.7 169.0215.44 192.5 189.0316.23 222.3 261.0RMS ERROR = 9.504

944.5 7.0 12473.9 37.4

THICK/RES 3.0013 3.0356 0.3103 0.5S42


103

ITERATION IMO. 1 5 , VES NO. 10

LAYER T H I C K N E S S ELEV RHO THICKSRES1 0 . 6 3 6 9 1 . 0 3 2 . 0 5 1 . 72 3 . I S 6 8 8 . 9 3 3 . 0 1 0 3 . 33 1 0 - 0 0 6 7 8 . 6 4 0 0 . 0 4 0 0 0 . 14 3 . 4 - i 6 4 5 . 8 1 0 0 . 0 3 4 0 . 65 7 . 3 9 6 3 4 . 6 3 . 9 3 0 . 56 6 0 3 . 8 2 8 0 . 0

• SPACING MODEL RHO FIELD RHO1 . 0 0 5 6 . 3 6 9 . 41 . 4 7 5 5 . 4 5 6 . 12 . 1 5 4 5 . 6 4 4 . 33 . 1 6 4 2 . 2 4 0 . 84 . 6 4 4 6 . 5 4 3 . 66 . 8 1 5 3 . 6 5 6 . 0

1 0 . 0 0 7 7 . 6 7 3 . 81 4 . 6 3 1 0 0 . 1 9 5 . 02 1 . 5 4 1 2 0 . 4 1 2 1 . 03 1 . 6 2 1 2 9 . 1 1 5 5 . 04 6 . 4 2 1 1 7 . 9 1 4 6 . 06 8 . 1 3 8 9 . 7 3 9 . 0

1 0 0 . 0 0 5 4 . 3 5 3 . 31 4 6 . 7 8 6 0 . 4 6 7 . 5

R MS ERRaR‘ = 9 . 7 9 5

IT ERA TI GN N G . 1 5 , VES NO. 1 0

LAYER T H I C K M E S S ELEV RHO THICK*RE51 0 . 7 4 6 9 1 . 0 8 3 . 5 6 1 . 52 2 . 2 6 6 9 8 . 6 2 5 . 7 5 8 . 03 1 4 . 3 3 6 3 1 . 2 3 0 0 . 4 4 4 6 9 . 24 6 3 2 . 4 2 5 . 0

S PACI NG MODEL RHO F I E L D RHO1 . 0 C 6 9 . 5 6 9 . 41 . 4 7 5 6 . 9 5 6 . 12 . 1 5 4 4 . 6 4 4 . 83 . 1 6 3 9 . 7 4 0 . 94 . 6 * 4 5 . 0 4 3 . 66 . 8 1 5 3 . 9 5 6 . 0

10 . 0 0 7 8 . 4 7 3 . 81 4 . 6 3 1 0 0 . 7 9 5 . 02 1 . 5 4 1 2 1 . 4 1 2 1 . 03 1 . 6 2 1 3 2 . 0 1 5 5 . 04 6 . 4 2 1 2 3 . 2 1 4 6 . 06 3 . 1 3 9 3 . 9 3 3 . "

1 0 0 . 0 0 5 3 . 7 5 3 . 3

RM5 EE 3DR = 7 . 5 2 1

THICK/RES0 . 0 0 7 70 - 0 9 5 40 . 0 2 5 00 . 0 3 4 12 . 0 3 8 6

THI C. K/ R5S0 . 0 0 3 30 . 0 8 7 7C . C 4 9 5


104

ITERATION NO. 15* VES NO. 11LATER THICKNESS ELEV RHO THICKSRES THICK/RES1 0.73 639.0 2795.9 2027.5 0.00032 0.76 686.6 475.1 361.2 0.00163 0.43 684.1 25.9 12.4 0.01854 17.41 682.6 150.0 2511.4 0.11415 3.37 625.4 22.0' 74.3 0.15306 614.4 207.2

SPACING MOOEL RHO FIELD RHO1.00 2108.0 2173.01.47 1470.8 1340.02-15 773.4 834.03.16 312.2 306.04.64 142.4 145.06.81 122.4 110.010.00 129.9 133-014.63 135.1 163.021.54 134.8 137.031.62 129.3 122.046.42 126.3 124.063.13 134.0 141.0100.00 150.3 147.0

RMS ERROR = 7. 131

ITERATION NO. 10, VES NO. 11LAYER THICKNESS ELEV RHO THICK*RES THI CK/ RES

1 0 . 72 6 3 9 . 0 2 7 9 6 . 0 2 0 1 0 . 6 0 . 0 0 9 32 0 . 7 9 6 3 6 . 6 4 3 0 . 0 3 7 9 . 4 0 . 0 0 1 63 0 . ? 7 6 3 4 . 0 3 3 . 0 3 3 . 1 0 . 0 2 3 04 1 4 . 6 6 6 3 1 . 2 16 5 . 0 2 4 1 9 . 0 0 . 0 3 3 95 5.55 5 3 3 . 1 3 0 . 0 1 7 5 . 6 0 . 1 9 4 36 6 1 3 . 9 2 2 3 . 0

SPACI NG MOOEL RHO FI ELD RHO1 . 0 0 2 1 0 1 . 5 2 1 7 3 . 01 . 4 7 1 4 6 5 . 0 1 3 4 0 . 02 . 1 ? 7 7 8 . 1 8 3 4 . 03 . 1 6 3 1 4 . 4 3 0 5 . 04 . 6 4 1 4 1 . 5 1 4 5 . 06 . 3 1 1 2 1 . 3 1 1 0 . 9

1 2 . 0 0 1 3 1 . 5 13 3 . 01 4 . 6 ? 1 3 ? . 5 16 3 . 92 1 . 5 4 1 3 7 . 6 1 3 7 . 02 1 . 6 2 1 2 9 . 7 1 2 2 . 04 6 . 4 2 1 2 4 . 7 1 2 4 . 06 3 . 1 3 1 3 3 . 2 1 4 1 . 0

I O C . 0 ' 1 ? 2 . 9 1 4 7 . 0o m; E’ r o ? = 5 . 6 5 0


105

ITERATION NO. 4, VES NO. 12LAYER THICKNESS ELEV RHO TH1 0.69 689.0 ’ 408.02 9.56 636.7 39.03 9.00 655.4 660.04 625.8 53 32.0

SPACING MODEL RHO FIELD RHO1.00 238.5 283. 01.47 191.3 196.02.15 102.1 104.03.16 56.1 53.34.64 43.9 44.76.81 43.1 43.810.00 46.9 47.614.63 56.4 54.521.54 72.1 62.931.62 90.9 J 98.246.42 106.0 124.068.13 109.2 120.0100.00 95.8 109.0146.73 70.8 94.5

280.2 373.3

5939.S

RMS ERROR = 9.981

i t e ° a t i o ,m NJ « c * - f v = r> 1 ?LAYER THICK NESS ELEV •2 Hu TH

1 0 . 5 ? 6 3 9 . C 49 3 . 0 -

2 9 . 8 0 6 3 5 . 7 3 9 . 13 9 . 32 6 5 4 . 6 6 6 0 . 0 .4 6 2 2 . 4 5 3 . 0

SPACING MODEL RHO FIELD RHO1 . 0 0 2 3 3 . 4 2 3 3 . 01 . 4 7 1 9 1 . 3 19 5 . 92 . 1 5 1 0 2 . 1 10 4 . 03 . 1 5 5 6 . 1 5 3 . 34 . 5 4 4 3 . 9 4 4 . 76 . 3 1 4 3 . 3 4 3 . 3

10 . 0 0 4 6 . 7 4 7 . 51 4 . 5 3 5 5 . 3 5 4 . 52 1 . 5 4 7 1 . 9 5 2 . 93 1 . 6 2 9 2 . 2 9 3 . 24 6 . 4 2 1 1 3 . 7 1 ? K A

* U * • -

6 ■: . 1 1 1 2 9 . 3 J* ■' 9 ■1 ' •s «•« ; w • v j 1 1 4 . 1 1 C -3 . 91 4 6 . 7 3 9 5 . 1 9 4 . 5

THICK-.5ES 235.2332. 9

5 AS 0.1

ERROR = 5 . 3 9 5

THI CK/ RES0.00170.2451.0.0135

t h : c < / ~n 0 n 1- . - V -C . 2 5 10.014


X i n ̂X J. i/ .f W | I wf V".D

; LAYS* THICKHSSS ELEV

« j . i j

RHO rHICK*RES THICK/RES, 1 0,29 689.5? 1461,0 416.6 ■ 3-. 0002

2 5,7 3' 583,1 45.3 256.7 3-, 176 83 12,54 669,3 365.? 3549,3 3',02894 '5 .52' 534.8 9 .? 49.4 3.6123

.. 5' ' 515,7 145,3 :

SPACING MODEL RMQ FIELD RHO--------------

1.20 185.1 272,31.47 59.3 62.22.15 • 49.2 45,83,16 47.7 42,34.64 49.6 45.3•5.31 55.7 54,317,22 65,3 53.914.58 • 85.1 97.521,54 125,4 113,331,52 119.3 125,345,42 119.3- 119.368.13 135.R 99.3

1 95.c ?7 , 2<45.78 •j M f i :■ i . 5

RMS. ERROR = 7 . 1<>5

I TERATI ON NO . 4 , VES NO. 13

LAYER THICKNESS ELEV RHO1 0 . 29 6 5 9 . 0 1 4 7 1 . 02 4 . 3 3 6 3 3 . 0 4 0 . 0-> 9 . 7 1 6 7 2 . 0 3 7 3 . 04 1 2 . 9 0 6 4 0 . 2 2 3 . 93 5 9 7 . 9 1 3 6 . 3

S PACING MGOEL RHO FI ELD RHD1 . 0 0 1 9 2 . 4 2 0 2 . 01 . 4 7 6 7 . 0 6 2 . 22 . 1 5 4 4 . 4 4 6 . 33 . 1 6 4 3 . 3 4 2 . 04 . 6 4 4 5 . 2 4 5 . 36 . 3 1 5 4 . 1 5 4 . 3

i o . o o 6 3 . 4 S 3 . 91 4 . 6 5 3 7 . 7 3 7 . 52 1 . 5 4 1 0 7 . 0 1 1 3 . 03 1 . 5 2 1 1 9 . 9 1 2 5 . 04 - 5 . 4 2 1 1 7 . 5 1 1 9 . 76 3 . 1 2 1 0 5 . 1 9 3 . 3

1 /■> ' ± • -V 9 6 . 5 9 7 . 21 4 - 5 . 7 5 9 3 . 7 1 0 1 . 0

R‘4S ERROR = 4 . 5 1 6

THICK*RSS 423.* 1 9 5 . 3

3 6 2 1 . 4 2 9 5 . 7

T HI C K/ R £ S 0 . 9 0 3 2 0 . 1 2 1 90.32 60 0.56:9


107

I T E R A T I O N NO. I S , VES NO- 14

LAYER THICKNESS ELEV RHO T HI C K* 3 5 S THI CK/ RES1 0 . 7 7 6 9 0 . 0 1 9 7 . 1 1 5 0 . 9 0 . 0 0 3 92 . V« 6 . 4 7 6 8 7 . 5 * * 4 1 . 9 2 7 1 . 3 0 . 1 5 4 3

. 3 1 0 . 6 8 6 6 6 . 3 6 5 0 . 0 . 6 9 3 9 . 3 0 . 0 1 6 44 w 8 . 0 0 6 3 1 . 2 6 . 3 2 - f r 5 4 . 1 1 . 1 3 3 75 6 0 5 . 0 1 2 5 . 0

SPACING MODEL RHO FI ELD RHO1 . 0 0 1 5 9 . 4 1 6 1 . 0

. 1 . 4 7 1 2 3 . 4 1 2 2 . 02 . 1 5 3 4 . 1 3 4 . 53 . 1 6 5 5 . 4 6 0 . 04 . 6 4 4 9 . 7 >♦5. 46 . 9 1 5 1 . 6 5 3 . 6

1 0 . 0 0 6 1 . 4 6 5 . 31 4 . 6 3 7 9 . 5 3 1 . 92 1 . 5 4 1 0 3 . 3 9 9 . 03 1 . 6 2 1 2 6 . 6 1 1 9 . 04 6 . 4 2 1 4 0 . 1 1 3 4 . 0

-• 6 8 . 1 3 „ 1 3 5 . 3 1 4 9 . 01 9 0 . 0 0 / 1 1 3 . 6 . 1 1 3 . 0

, 1 4 6 . 7 3 iy 9 1 . 6 - 8 7 . 8

fr R M S ’. E R3&.0R k. 5-093

I TERATI ON NO. 1 5 , VES NO. 1 4

» f tvcp t u T r KN p SS ELP V RH2 THICK*RESL A p t h i .k h . ss .l v ? .oor|

? - P t ? f : l s !5.o S / t i s4 m ? I I I : ! i i : l - i t s : ? s . $ «

5 7 5 . 4 1 7 5 . 0

SPACING MODEL RHO P I P L3 RHO1 . 3 0 1 5 7 . 3 1 5 1 . 91 . 4 7 1 3 5 . 9 1 2 2 . 0

■ 2 . 1 5 9 1 . 1 8 4 . 53 . 1 6 5 4 . 3 6 3 . 04 . 5 4 4 1 . 2 4 5 . 46 . 3 1 4 6 . 9 5 3 . 6

1 C . 0 ? 6 3 . 1 6 5 . 31 4 . 6 5 35.4 8 1 . 32 1 . 5 4 1 1 0 . 3 9 9 . 03 1 . 6 2 1 3 2 . 0 1 1 3 . 04 o . 4 2 1 4 1 . 3 1 3 4 . 96 3 . 1 3 1 3 1 . 9 1 4 9 . 0

1 2 0 . 0 0 1 0 9 . 4 1 1 2 . 21 4 6 . 7 3 9 2 . 2 3 7 . 3

RMS ERROR = 3.436


108

TER*IIOT. MO, 1 5 , v r s MO. 15

aver n i r : * c j r s ' s ~ 'ELr v~ . . . . rHTC:^ Rr s -~ r H I ^ K ' /R E 5 ~1 3 , 5 5 5 8 ? , ? 4 5 2 , 1 2 5 2 . 2 31, 0 0 1 27 4 , 3 5 ' 5 6 7 . 2 4 3 , 3 1 7 4 . 4 3'. 1 3 9 33 : 1 3 , 3 1 6 7 2 . ? , 4 3 3 , 3 . 4 3 3 2 , 2 : 3', 0 2 5 34' 5 , 4 9 . 6 4 3 , 0 9 , 3 2^" 4 9 . 3 3 , 6 * 8 35. y *sr.';Zlr® 6 2 2 . 1 2 3 5 . 2 , / / '

SPAJIMS MODEL RHO FIELD; RHO1 . 3 0 2 6 1 . 3 2 8 9 , 3 :1 . 4 7 1 5 3 . 7 1 5 3 , 3 •2 . 1 5 7 6 . 1 7 4 . 63 . 1 6 53 . f i 4 4 , 24 , 6 4 4 9 , 5 3 9 , 86 . 9 1 5 9 . 2 5 3 . 4

13', 30 " ' 7 4 , 6 7 2 , 6. 1 4 , 6 8 •i:: 9 6 , 3 1 3 5 , 0v - v 2 1 . 5 4 1 1 6 . 7 1 3 3 . 0 - ,.v

3 1 , 6 2 1 2 9 , 1 1 3 6 , 04 6 , 4 2 . ' 1 2 7 , 3 1 2 5 , 36 8 , 1 3 . 1 1 5 . 6 1 1 3 . 0

103>,33 1 1 3 . 0 .. : 1 3 3 , 0 f1 4 6 , 7 8 - 1 2 1 . 5 •... 1 3 5 , 0

SMS, ERROR, s; 1 0 , 2 4 7

ITERATION N j• 15, VES NO. 15LA'fER THICKNESS SLSV RHO THICKER? 3 THlCK/ R=S

1 G . - j l $39.3 453.9 ZZ$m,2 2.74 637.0 26.33 8,52 67 8.0 451.4 384 3.0 0.01894 16103 650.0 25.0 400.7 0.64115 597.5 257.6

SPACING MODEL RHO FIELD RHC1.00 273.7 239.01.47 161.7 153.02.15 73.9 74.63.14 41.9 44.24.64 43.3 3 9.56.31 56.3 52.4

, ^ s - -* f > 7 £1 • j » -J • ‘ £ • ~14,6 2 99.0 105.021.5 4 119.5 133.331.62 130.746.4 2 127.1 126.353.12 114.3 110.0102.02 109.5 10 9.114o.7 ’ 123.2 125.?

R*S ERROR = 6.252


109

I T E R A T I O N NO. 1 5 , V £ 3 NO. 16

Y zP. THICKNESS ELEV RHO THICK JsRES1 0.43 692.0 531.7 277.42 2.53 690.4 3 9.9 13 4.93 7.24 631.8 300.0 2172.14 2.09 653.1 44.0 . 92.15 9.00 651.2 700.0 6300.06 621.7 72.0

SPACING MODEL RHO FIELD RHO1.00 255.3 265.01.47 133.5 126.02.15 66.4 72.33.16 53.6 53.94.64 62.0 52.66.31 79.7 80.810.00 102.9 106.014.63 123.3 126.021.54 152.7 142.031.62 173.2 165.046.42 134.3 139.069.13 173.2 204.0100.00 150.4 160.0146.7 3 114.5 115.0

THICX/RSS 0.0003 0.0659 0.02*1 0 • 0475 0.C129

RMS ERROR = 347


1 23456

THICKNESS ELEV RHO 0.61 691.0 280.01.71 639.0 19.92. 23 693.4 120.05.46 676.1 . 740 . 010.00 653.2 200.0625.4 62.1

SPACING MODEL RHO FIELD RHO1.00 176.1 16 3.01.47 106.1 110.02.15 53.9 52.13.16 37.3 40.04.64 43.6 43.46.81 59.4 55.5

10.00 81.4 74.514.63 108.5 101.021.54 137.2 137.031.62 159.9 177.046.42 166.2 198-068.13 149.6 156.0100.00 117.1 100.0146.78 87.0 81.0

THICK*RES 171.9 34.1 267.1 4038.7 2000.0

THICK/RES0.00220.03580.01350.00740.0500

RMS ERROR = 8.435


ITERATION NO. 15* VES NO. 13LAYER

123456

. .THICKNESSI ELEV • -RH0 THI CK*RES1 . 1 0 6 9 0 . 0 1 1 5 . 0 1 2 6 . 30 . 4 3 6 3 6 . 4 3 0 . 0 1 4 . 53 . 6 2 6 3 4 . 8 1 2 3 . 0 4 4 5 . 17 i 0 0 6 7 2 . 9 3 5 0 . 0 5 9 5 0 . 2

1 2 . 0 0 6 5 0 . 0 4 0 0 . 0 4 8 0 0 . 46 1 0 . 6 7 0 . 1

THI CK/ RES0 . 0 0 9 50 . 0 1 6 20 . 0 2 9 4Q. QQ320 . 0 3 0 0

SPACING1.001 . 4 72 . 1 53 . 1 6 4 . 6 4 6 . 3 1

10 .00 1 4 . 6 3 2 1 . 5 4 3 1 . 6 2 V 4 6 . 4 2 X 6 6 . 1 3

100.00 1 4 6 . 7 3

MODEL RHO 1 0 3 . 8

- 1 0 1 . 29 1 . 78 3 . 09 7 . 3

' 1 1 9 . 61 5 4 . 1

i. 1 9 9 . 22 4 6 . 62 3 0 . 62 8 1 . 5

, 2 3 8 . 2/ 1 6 8 . 1 ' 1 0 9 . 5

FIELD RHO1 0 5 . 01 0 9 . 0

8 9 . 78 5 . 29 9 . 7 , ,

HOiO"."«'1 4 8 . 0200.02 5 2 . 03 1 3 . 03 0 6 . 02 5 9 . 02 1 3 . 01 0 3 . 0

RMS ERROR = 7 . 5 1 1

I TERATI ON NO. 1 5 * VES NO. 1 9

LAYER THICKNESS ELEV RHO THI CK*RES THI CK/ RES1 0 . 7 3 6 3 8 . 0 1 2 0 . 0 3 3 . 2 0 . 0 0 6 12 0 . 1 3 6 3 5 . 6 3 5 . 0 6 . 4 0 . 0 0 5 23 4 . 2 3 6 3 5 . 0 1 3 0 . 0 5 4 9 . 9 0 . 0 3 2 54 9 . 1 1 6 7 1 . 1 9 0 0 . 0 S 2 0 1 . 3 0 . 0 1 0 15 6 4 1 . 2 1 1 0 . 0 .......

SPACING MODEL RHO' FI ELD RHO1 . 0 0 1 1 0 . 3 1 0 3 . 01 . 4 7 1 0 4 . 9 1 1 0 . 02 . 1 5 1 0 4 . 6 1 0 1 . 03 . 1 6 11 2 . 4 1 0 3 . 04 . 6 4 1 2 7 . 3 1 3 3 . 06 . 3 1 1 5 1 . 1 1 5 4 . 0

1 0 . 0 0 1 3 3 . 5 1 5 3 . 01 4 . 6 3 2 3 7 . 1 2 2 3 . 02 1 . 5 4 2 8 3 . 1 2 5 5 . 03 1 . 6 2 3 0 5 . 2 3 0 7 . 04 6 . 4 2 2 3 6 . 2 3 2 4 . 06 3 . 1 3 2 3 0 . 4 2 2 5 . 0

1 0 0 . 0 0 1 6 9 . 1 1 5 7 . 01 4 6 . 7 3 1 3 1 . 6 1 3 5 . 0

RMS ERROR = 5 . 4 4 3


Ill

ITERATION NO. VES NO. 20LATER THICKNESS RHO1 0.62 683.0 294.02 5.03 631.0 47.93 664.3 173.1

SPACING MOOSL RHO FIELD RHO1.00 202.6 200.01.47 137.9 141.02.15 84.6 83.93.16 60.1 53.34.64 55.3 57.46.31 59.4 53.210.00 70.1 69.214.63 86.3 89.121.54 105.3 103.031.62 124.3 125.0RMS ERROR = 2 - 1 6 9

182.5243.5THICK/RES0.00210.1060

ITERATION NO. VES NO. 21LATER THICKNESS ELEV RHO1 1.09 637.0 361.02 3.64 633.4 50.03 0.23 671.54 25.00 670.7 4000.05 588.7 600.0

THICKCRES393.0132.032.2100000.0

THICK/RES0.00300.0723-0.0016“0.0063' ;

. SPACING MODEL RHO1.00 325.31.47 277.22.15 201.73.15 126.24.64 37.36.31 92.510.00 125.814.63 130.321.54 257.431.62 361.446.42 493.8

.... - 58.13 646.5100.00 794.8146.78 897.5

FIELD RHO336.0282.0191.0133.0 85.2 39.7116.0153.0225.0361.0574.0760.0931.0912.0

RMS ERROR. = 9.273


112

ITERATION NO. 6, VES NO. 22LATER THICXNESS ELEV RHO th:1 0.67 687. 0 299.82 3.57 684.3 41.63 673.1 156.2

SPACING MODEL RHO FIELD RHO1.00 215.4 221.01.47 148.4 142.02.15 33.0 39.43.16 58.0 59.14.64 53.2 52.76.31 60.5 53.110.00 73.9 73.914.63 90.3 97.921.54 107.1 102.0

201.7148.2

RMS ERROR * 3.832

ITERATION NO. 15» VES NO. 23TER THICKNESS ELEV RHD THICX*RES1 0.65 638.0 2270.7 1470.02 0.50 635.9 423.1 211.73 1.04 634.2 24.0 25.04 12.45 630.3 438.9 ' 6087.75 5.16 640.0 25.0 129.16 20.02 623.0 216.0 4324.17 557.4 57.0

SPACING 1.00 1.47 2. IS 3.16 4.64 6.81 10.00 14.63 21.54 31.62 46.42 68.13 100.00 146.73

MODEL RHO1565.7993.3450.0156.996.3113.6155.0193.1222.4229.0205.6163.7124.295.1

FIELD RHO 1432.09 3 6 . 0 4 3 1 . 3154.091.5113.0156.0205.0251.0215.0195.0168.0 125.094.5

RMS ERROR 5.436

THICX/RES0.00220.0858

THICX/RES0.00030.00120.04340.02550.20630.0927


113

ITERATION M3. 15, VES NO. 24layer thi cknes s elev

1 1 . 1 7 6 6 5 . 02 5 . 8 9 6 8 1 . 2345

9 . 8 26.01

6 6 1 . 86 2 9 . 6.£09*9.

RHO IHICK»RES 8 4 . 6 9 9 . 2

- J i^ 0 ______ 1.64,81 4 0 . 0

7 . 02 B l s Z -

1 3 7 4 . 4 4211

t h i c k / r e s31. 013 9

___0j 2102 _3', 0701 3 , 8 5 8 3

SPACING MODEL RHO FIELD_MO_1 . 3 01.4.72 . 1 53 . 1 64 . 6 4S'. 81

13.00 1 4 . 6 8 2 1 . 543 1 . 6 24 5 . 4 26 3 . 1 3

1 0 3 . 0 01 4 5 . 78

7 9 . 87 2 . 9 3.1,1. 4 7 , 3 37,7 -15.X3 8 . 44 5 . 6

J53, 4_ 5 3 . 15 9 . 36 1 . 77 2 . 59 3 . 3

8 1 . 27 3 . 0

_5J.8_ 4 7 , 63 8 . 0 Jl'.X3 9 . 4 4 5 . 2

_5 3 ».75 7 . 56 3 . 1

.59.6. ,7 2 . 19 4 . 5

RMS. ERROR s: 3 . 13 2

ITERATION NO. 1S> VES NO. 24 LAYER THICKNESS ELEV

345

1.30 7.46 S. 29 26.33

635.0 631.7 657.2630.0 543.6

RHO9 3 . 132.2 139.930.0236.8

THICK.~R£S83.32 4 0 . 01159.7739.9

THICK/RES0.0114C.23130.05930.6777

SPACING I. 00 1.472.152.16 4.64 6 . 8 110.0014.6821.5431.324o.4263.12

100.00146.73

MODEL RHO31.372.659.546.633.935.33 9 . 144.352.257.6 5 9.9.62.372.392.6

FIELD RHO31.2 73.C 5'3. 347.633.027.139.445.250.757.563.159.$...

72.194.5R‘1S ERROR = 2.335


114

iteration; no. is, ves no‘. 25layer t h i c k n e s s elev RHO THICIURES THICK/RES

1 3 . 8 $ 6 8 3 . 0 3 1 9 . 3 2 7 2 . 9 3 . 0 0 2 72 0 . 2 9 6 8 5 . 2 2 3 . 3 5 . 5 3'. 013 83 6 . 5 1 6 8 4 . 3 3 4 . 7 2 2 6 . 2 3 . 1 8 7 44 7 . 1 2 6 6 2 . 9 1 3 3 . 3 7 1 1 . 7 3 . 0 7 1 25 . 4 . 7 3 6 3 9 . 6 1 5 . 3 7 3 l 3 3 . 3 1 3 56 6 2 4 . 2 1 3 3 . 3

' SPACING ... : HODEL RHO FIELD RHOi . a a 2 5 7 . 5 : 2 4 3 . 31 . 4 7 1 9 2 . 4 1 9 9 . 02 . IS 1 1 5 . 1 1 2 4 . 33 , 1 6 6 3 . 9 5 4 . 84 . 6 4 4 1 . 2 4 3 . 6

. 6 . 8 1 3 8 , 6 4 3 , 31 3 . 0 0 4 1 , 0 4 3 , 4 -

. . . . 1 4 . 6 8 . 4 5 . 7 4 5 . 02 1 . 5 4 5 3 . 6 5 3 . 43 1 . 5 2 5 4 . 2 5 5 , 34 6 . 4 2 5 7 . 9 5 6 . 86 8 . 1 3 6 4 . 2 6 5 . 3

1 0 3 . 3 0 7 2 . 8 7 2 . 1

RMS. ERROR s. 4 . 6 7 8

ITERATION NO. 15, VES NO. 25LAYER THICKNESS ELEV RHQ THICK--*R5S THICK/RES1 0.97 683.0 313.7 277.1 0.0027

2 0.60 635.1 19.6 11.8 2 - ^ 0 33 8.04 633.2 33.2 315.5 0.20434 4.37 656.8 100.0 437.1 0.94375 17.17 640.8 45.0 772.3 0.33176 534.5 100.0

SPACING MOOEL RHQ FIELD RHC1.00 258.4 243.01.47 193.4 199.02.15 115.1 124.C3.16 60.2 54.34 • 6 ̂ 41.4 4 3.6o.21 39.7 40.310.00 41.7 40.4

14.59 4 5.2 45.021.54 49.3 50.431.62 54.2 55.346.42 53.4 56.96^.13 64.3 6 5.3

1 j 0 .0 c 72.2 72.1"MS ERROR = 4.331


ITERATION: NO. ■ 6 , VES N0‘. 26

11

layer t h i c k n e s s elev RHO THICK#RES THICK/RES1 0 . 7 2 : 6 8 9 . 0 7 5 0 . 9 5 3 7 . 0 3*, 0 0 1 32 0 . 4 1 6 8 6 . 7 1 7 . 8 7 . 2 at. 0 2 2 93 . 2 r 63 6 8 5 . 3 ' , 5 5 . 9 . 1 4 9 , 8 3', 0 4 8 34 1 1 . 1 7 6 7 6 . 5 1 1 2 . 0 . 1 2 5 1 , 2 . 3 . 0 9 9 7S •" 1 . 6 S 6 3 9 , 9 ....... 2 2 . 0 ' 3 6 . 2 at. 0 7 4 86 6 3 4 . 5 1 3 2 . 2

SPACING MODEL RHO FIELD RHO1 . 0 0 5 2 3 . 7 5 1 5 . 01 . 4 7 3 3 3 . 0 3 3 9 . 02 . 1 5 1 5 7 . 2 1 5 8 . 03 . 1 6 7 2 . 3 7 3 . 94 . 6 4 ' ’ 5 8 . 1 5 9 . 16 . 8 1 6 4 . 3 6 4 . 9

J. 1 0 . 0 0 . . 7 3 . 8 - 7 2 , 4 .

1 4 , 6 8 8 2 . 9 8 4 . 1-...... 2 1 . 5 4 ....... , Q 0^ 0 8 8 , 1 - .........

3 1 . 6 2 ’ 95.2 . 9 7 . 1_ . 4 5 . 4 2 - ........' 1 0 1 pi .... 1 0 1 . 0

6 8 . 1 3 1 0 3 . 8 1 3 7 . 01 0 0 . 3 0 1 1 6 . 8 1 1 9 . 01 4 6 . 7 8 1 2 3 . 0 __ 1 .2 2 ,0 ...

RMS. ERROR 3: 1 . 5 6 6

ITERATION n o . 1 5 » VES NO. 2 6

LAYER THICKN ESS ELE1 C. 7 1 6 3 9 . 02 0 . 4 1 6 8 6 . 73 5 . 7 0 6 8 5 . 34 1 0 . 6 7 6 6 6 . 65 3 . 8 7 6 3 1 . 66 6 1 8 . 9

RHO7 5 0 . 0

1 8 . 0 66.1112.1 4 8 . 1

1 3 2 . 0

THI CK* R: S5 3 0 . 4

7 . 33 7 7 . 0

1 1 3 6 . 11 3 6 . 0

THI CK/ RES 0 • COO 9 0 . 0 2 2 7 0 . 0 8 6 2 0 . 0 9 5 2 0 . 0 8 0 6

S P I C I N G MODEL RHO FI ELD RHO l . O C 5 1 9 . 9 5 1 5 . 01 . 4 7 3 2 3 . 2 3 2 9 . 02 . 1 5 1 5 5 . 6 1 5 9 . C3 . 1 6 7 4 . 3 7 0 . 94 . 6 4 6 0 . 6 5 9 . 16 . 3 1 6 4 . 1 6 4 . 9

1 0 . 0 0 6 9 . 8 7 2 . 41 4 . 6 3 7 7 . 0 8 4 . 12 1 . 5 4 8 4 . 7 3 3 . 13 1 . 6 2 9 1 . 7 9 7 . 14 6 . 4 2 9 3 . 5 1 0 1 IC6 3 . 1 2 . 1 S 6 . 4 . . 1 0 7 . 0

10C- . O0 1 1 4 . 6 1 1 3 . 0145.7 3 121. 12-.-

RMS ERROR * 3 . 7 3 0


ITERATION NO. 15, VES NC. 27LAVER

2 *•... 3 . ■

' 4

THICKNESS ELEV 0 . 3 0 6 9 0 . 0A . 15 . 6 8 9 . 09 . 7 0 ' 6 7 5 i 4

6 4 3 . 6 ,

SPACING 1.00 1 .4 7 . 2 . 1 5

' ' 3 . 1 6 4 . 6 4 6 . 8 1 10.00

1 4 . 6 8 • 2 1 . 5 4

3 1 . 6 2 4 6 . 4 2 6 8 . 1 3 100.00

1 4 6 . 7 8

MODEL RHO- - 7 9 . 6

4 3 . 6 . 3 5 . 6 -

— '35. 7-^4 8 . 56 3 . 68 3 . 2

1 0 3 . 71 1 9 . 91 2 5 . 91 1 9 . 61 0 6 . 394.5

RHO 3 9 2 . 8

3 2 . 1 3 3 9 . 2

8 2 . 8

THICK*RES1 1 6 . 11 3 3 . 3

3 2 8 9 . 3 -

THICK/RES0 . 0 0 0 80 . 1 2 9 2

' 0 . 0 2 8 6

FIELD RHO7 9 . 44 3 . 93 5 . 3

- 3 6 . 4 ......-3 9 . 64 7 . 26 2 . 67 9 . 3

1 0 9 . 0 1 2 7 . 0 .1 2 8 . 01 1 6 . 01 0 3 . 0

9 4 . 5RMS ERROR 2 . 8 3 1

I-TES A iL S lL i? . «_1.5 ,

l ay e r

23

THICKMESS ELEV 0-«-33 6 9 3 . 0

6 8 9 , 0 6 7 5 . 6

. 4 , 0 91 3 , 3 9

RHO. rHICK#RES -3 9 .5 .3 U 6 j j _

3 2 . 03 1 8 . 0

1 3 1 . 03 3 0 4 . 8

THICK/RES 1', 0 0 0 7

3*, 12 7 9

SPACING-

— ---- ri4,iy

MODEL RHO FIELD RHO■ 1 * 3 0 7 9 , 7 7 9 . 4

1 . 4 7 4 3 . 5 4 3 . 82 . 1 5 3 5 . 5 .35.^3. .. .........3 . 1 6 3 5 . 7 3 6 . 44 . 6 4 3 9 . 6 3 9 . 66 . 9 1 4 8 . 6 „ 4 7 . 2 ____ _______ _______________

1 3 , 3 0 6 3 . 7 6 2 . 61 4 . 5 8 8 3 . 1 7 9 . 32 1 . 5 4 ______1 . 33 , 6 . . . 1 0 9 . 3 ____________________________3 1 , 6 2 1 1 9 , 7 1 2 7 . 04 6 . 4 2 1 2 5 . 7 1 2 8 , 06 8 . 1 3 1 1 9 . S . . 1 1 6 , 0 _____ _ ____ ________________

103'. 00 1 0 6 . 4 1 0 3 . 01 4 6 . 7 8 9 5 . 6 9 4 . 5

RMS ERROR s 2 . 9 4 9


117

ITERATION- NO. 15. VJS_JJ p , 2.8.l a y e r t h i c k n e s s elev

1 0 . 531 6 9 2 . 0RHO- THICK»RES 1 7 0 . 3 8 5 . 6

t h i c k / r e s3'. 0 0 3 3

2 2 . 8 33 1 2 , 1 34

6 9 3 , 46 8 1 . 16 4 1 . 3

2 6 . 5 ,■ 7 5 3 . 3

6 5 . 8

7 5 : 29 0 9 7 . 4

3', 1 0 6 8 3', 0 1 6 2

SPACING MODEL RHO FIELD RHO1 . 3 3

s 1 , 4 7 . 2 . 1 5

9 6 . 26 3 . 3 3 9 . 7

9 5 . 4 6 1 , § 3 8 . 7

3 . 1 64 . 6 46 . 8 1

3 5 . 94 2 . 75 7 . 8

3 5 . 34 3 . 45 7 . 5

1 3 , 3 01 4 . 6 82 1 . 5 4

8 3 . 51 1 3 . 11 4 4 . 4

7 8 . 31 3 6 . 01 4 4 . 0

3 1 , 6 24 6 . 4 26 8 . 1 3

1 7 7 . 31 9 6 . 91 9 3 . 8

1 8 6 . 02 3 5 . 01 9 2 . 0

103'. 30 1 4 6 . 7 3

1 5 7 , 21 1 3 . 9

1 5 3 . 01 1 5 . 0

RMS. ERROR s: 2 . 671

i t e r a t i o n : no . 1 5 , VES NO*. 29 •

l ay e r t h i c k n e s s elev1 3 . 6 2 6 9 4 . 02 2 . 0 7 6 9 2 . 0

. RHO THI 6 6 9 . 3

5 1 , 3 .

CK#RES416' .0

. _ 1 3 5 , 5

THICK/RES 3’. 3 0 0 9 3 ' , 0 4 0 5

3 9 , 3 54 9 , 3 3 '5

6 8 5 . 26 5 4 . 56 2 4 1 0

4 3 8 . 09 9 8 . 01 2 5 . 0

3 8 1 4 . 09 2 8 2 . 3

31. 0 2 2 9 3', 0 09 3

SPACING MODEL RHO FIELD RHO1 . 3 0 1.. 47 2 . 1 5

4 2 7 . 7 2 6 1 . 01 3 2 . 7

4 3 3 . 02 5 9 . 01 3 2 . 0 _

3 , 1 64 . 6 46 . 8 1

8 7 , 1. 9 5 . 81 2 5 . 1

8 9 . 6 , 9 0 . 7 1 2 7 , 0 _

1 3 . 0 01 4 , 6 82 i . 5 4

1 6 4 . 42 1 1 , 12 6 2 . 0

1 7 2 . 02 1 1 . 0 2 5 1 . 0

3 1 . 6 24 6 . 4 26 8 . 1 3

3 3 7 , 03 2 6 . 83 3 3 . 8

3 3 3 . 03 3 4 . 03 1 6 . 0

1 0 3 . 3 01 4 6 . 7 8

2 4 4 . 81 8 3 . 0

2 4 5 . 01 7 6 . 0

RMS. ERROR S: 2 . 9 5 4


iiFRwiSai so, 9, T s r ' \ y r 5 3

LAy5R' rHISKMSSS ELEV RHO THICK »R5S THICK/RES1 3 , 6 3 f a s . ? 1 8 2 , 7 11 O ' ““ ■ > , W S 5 ~2 5 , 63> 6 3 3 , 9 3 2 , 3 181 . 0 9>,173&.

_ 3 8 , 3 1 6 6 2 . 5 2 3 1 . 1 1 9 2 0 . S 3- .0362r*s' 4 ; B , 19 ■ - 63S~3 “ 7.2 57.2 1,1697^- • 5... '• ' 623,4 128,7

S ? A M ‘.’G MODEL RMO FIELD RHO1.3Z 129.4 128.21,47 9 2’. 2 ' 91,7 ..................*2 ,15 56,e 56.33.16 43.7 43,5

• 4,64 37.3 3T.8 ...6.81 , 42.P 39.8

13.20 47.5 47.9’ :: K: 14,68 - -'■'••v 58,4 •: " ' 54,5

21,54 > A 6 8 . 4 ̂68,3 iv:r- "I 31,62 „ t 72,2 77.9

46,42“ 67.4 73.6'..69‘,13 58.° . 53,7

103,30 55.7 56.4’14 - -v.:.. 64 ,7 / ••• . 67,5 -'-..i:''

• RMS, ERROR s 4. 154 ' • "^:'V ::

ITERATION NO. IE, V£S NO. 21LAYER THICKNESS ELEV • RHO THICK*RES THICK/RES1 1-33 S33.0 67.6 65.7 0.02902 0.99 - 678.5 15.4 "* 15.2 0.0642.3 5.83 .675.2 55.7 324.9 0.1043■i . Z - 5 ? 656.1 :. 140.1 1053.0 0.05395 • 17.84 . 631.3 ,29.0 . 517.3' 0.6151 \6 ........ - 572.8 205.4 — ■

SPACING 1.00 1.47 : 2.15 3.16 ‘ 4.646.31 10.00 14.68 .21.54 31.62 46.4 2 68. 13 100.00

DEL RHO FIELD RHD46.1 45.3 •43.9 45.040.0 39.935.8 35.5'34.9 " 34.938.7 38.745.6 45.753.6 54.061.0 60.065.3 64.365.3 69.370.7 66.7' 92.7 35.0RMS ERROR = 2.415


119

—Vi-Onfti lvi ' , -1V-,---W $——lfr.8:

layer t h i c k m e s s elev

W w g J 4 _ a . -..* — --1— .

RHO THICK#RES THICK/RES'.i 1 , 1 3 . 6 8 3 . 0 4 9 , 1 54._3__ 3., 0 2 3 52 2 , 09 * 6 7 9 , 3 2 5 , 0 5 2 , 2 3 ' , 08353 5 , 0 3 6 7 2 , 5 5 7 , 0 2 8 6 , 8 0*, 0 9 8 34 8 . 7 9 5 5 5 . 9 1 4 0 , 0 1 2 3 0 , 4 , 3<j362ff5 * 4 , 1 5 : 6 2 7 , 1 7 , 0 2 9 . 1 2<, 5 9 3 4 ,6 6 1 3 , 5 2 0 5 , 0

s p a c i n g MODEL RHO FIELD RHOV

- - . 1,00 . 4 6 . 3__ 4 5 . 31 . 4 7 4 3 , 8 4 5 , 02 . 1 5 3 9 , 9 3 9 , 9 •3 . 1 6 . . 3 5 , 9 . .... .........3 5 , 5 ____4 , 6 4 3 5 . 1 3 4 , 96 , 8 1 3 8 , 6 3 8 , 7 .

........... 1 0 , 3 0 . . . . .. 4 5 , 4 . 45,71 4 , 6 8 5 3 , 6 5 4 , 02 1 , 5 4 6 1 . 2 6 0 , 1

------ 3 1 , 5 2 . - _____ 6 5 , 4 _ --------- 6 4 , 8 _ .4 6 , 4 2 66,6 6 9 , 86 3 . 1 3 7 2 . 5 6 5 , 7

. . 1 0 0 , 3 2 . 6 2 . 7 .... 8 5 , 2 . . .

RMS. ERROR s: 2 . 4 7 4

ITERATION NO. 15, VES NO. 32LAYER THICKNESS ELEV RH31 0.67 537.0 144.3

2 S. 36 534.3 42.03 9.92 557.4 298.04 10.72 624.3 11.05 589.6 269.0

THICK*RS596.7351.32957.2117.9

THICK/RES0.00460.19900.03330.9745

SPACING MODEL RHO FIELD RHO1.00 113.8 117.01.47 38.6 35.92.15 64.3 65.03.16 50.9 52.24.64 46.2 45.26.31 46.5 45.0

10.00 50.3 50.114.68 60.0 59.4 .* 21.54 72.9 73.531.62 84.3 34.346.42 83.5 83.663.13 35.3 90.8100.00 83.3 73.5

RMS ERROR = 4.325


120

ITERATION NO. 15, VES NO. 33LAYER• 1 ..

• 2 ‘7- .... .345 • ••

THICKNESS ELEV RHO THICK*RES THICK/RES0.66 .688.0 242.2 160.3 0.00275.81- ■ 685.8 ... 45.3 262.8 0.128310^46... 666.8 - 320.8 '3354.0... 0.032620.20 632.5 30.0 606.0 0.6733566.2 164.1

SPACING MODEL RHO -. 1. 00 177.81.47 127.3... 2#15 - - 31.8'3.16 58.14.64 52.36.31 55.7..1C . 0 0 ..... 66,1. .. ..14.68 82.621 .54 100.331.6 2 112.146.42 111.968.13 102.1100.0 0 94.8

FIELD RHO175.0130.0 82.3' •56.5 '51.0 58.3 69.851.0-96.0103.0117.0102.094.0

RMS ERROR 3.125

rTFRTTroN-rjT-ir~■ r"S’ no. n .................... -....... ....layer t h i c k-iess elev rh? th tc:<*pes thick/res” 1 DT5T- TBTT**....... 742.5 ~ 162.2.........KZ>*27~'2 5.87 655.° 45,4 266.3 3,12943 10.55 566,6 235.2 353?.5 3.tfll54---- • 5.15 -631,9 ? , U 30 41.3 ' 0.64475 615,7 164.5

SPa : I v 3 MODEL RMQ f i e l d rmoi.?3 177.9 175.3

— r m ------- n 7 7 3--------1 3 2 7 2 —2.15 81.B 52.33.15 53.1 55.55754-------- 527*-------- 5T7S---5.91 55.7 53.3

12,?3 66.2 69,8— IT7frr-------- 8275--------8IT T

21.54 122.4 96. d31.52 112,2 108.245772-------rrr.'7------- i 1775“03,13 122.1 172.2

102.03 95.1 94.3

RMS. ERROR s-. 3 , 1 6 9


121

ITFRATi as VO, I f VRS MO. 34

LAVER I HI WVSSS ELEV RHO THICK^RSS TH1CK/RSS1

34

-5 -

3 . 5 1-5. -52-9 , 3 14 , 5 3

530,3 -536,-3- 5 6 3 . 2 541.>3

-52-5-S-3-

4 4 4 . ?- 6 7 . 9 -3 5 9 , 0

8,7•452,3-

2 2 6 . 4— 3 7 4 . - 9 -2 9 0 2 . 0 -

3 7 . 0

3'. 00 u -4 .081-2- a , 0 2 3 t 3 , 5 7 6 6

-SPftSSWS — PI ELD R^O-1.00 1 . 4 7

— 2 . 1 5 - 3 . 1 6 4 . 5 4

~ 6 t 8 1 — 10.00 1 4 , 6 0

—21-r54— 3 1 , 5 2 4 5 , 4 2 -

- 6 9 ^ 1 4 — 100,00 1 4 5 , 7 8

2 5 3 . 01 5 7 . 1

- 97 - . - 9 -7 7 . 97 6 . 0

-8-2-T-2-9 6 . 1

1 1 4 , 6428-1-4-1 2 7 . 61 1 1 , 5

- 9 3t &-9 0 . 2

101.0

2 5 0 . 0 160,3

- 9 7 , 4 -76,.07 5 . 8

- 8 5 . 3 -9 3 , 0

1 1 6 . 0 4 2 3 * 0 -1 2 4 . 01 1 3 . 0

- 4 7 . - 2 -8 7 . 8

101.0

RMS, ERROR s : 2 , 3 9 2

I TERATI ON NO. VES NO. 3 5

LAYER THICKNESS- ELEV L ■ ' 0 . 2 7 6 9 1 . 0

■ . 2 • 7 . 4 5 6 3 0 . 13~; 1 0 . 7 8 ' 6 5 5 . 7

4e 1 2 . 9 0 6 2 0 . 35 7 3 . 0

RHO T H I C K * 3 5 S3 5 4 . 1 9 5 . 0

3 8 . 1 2 8 3 . 74 0 6 . 1 4 3 7 6 . 0

1 4 . 61 9 9 . 9

1 8 3 . 8

THI CK/ RES 0 . 0 0 0 8 " 0 . 1 9 5 8 . 0_.J)265__

0 . 3 8 1 0

SPACI NG 1.00 1 . 4 7 2 . 1 5

.. 3 . 1 5 4 . 6 4 6 . 3 1 10.00

1 4 . 6 3 2 1 . 5 4 3 1 . 6 2

. 4 6 . 4 2 6 3 . 1 3 100.00

146.73 2 1 5 . 4 4

MODEL RHO7 0 . 54 6 . 04 0 . 529.54 0 . 24 3 . 2

, 5 0 . 26 3 . 19 0 . 3 9 6 . 9

1 0 6 . 4 1 0 5 . 2

9 3 . 49 3 . 5

1 1 1 . 5

FIELD RHO 7 0 . 74 5 . 54 1 . 63 3 . 3 4 0 . 04 3 . 55 0 . 36 0 . 7 7 3 . 99 9 . 3

1 1 3 . 01 0 3 . 0

9 7 . 234.5

117.05 MS ERROR =. 2.783


122

ITERATION VO, 7, VES NO, 35

l a y e r t h i c k n e s s e l e t ^ RHO- THICKvRES THTcK/RES.1 0,27 681,0 354,0 95.0 0‘, 0008

,.,••2 .. 7,45! • 680,1 v 38,0 283,2; 3', 1958 73 f2T, 9t 655,7 406,0 7428,8 3', 02 6 94 6,13 - 619,9 7.0 42,9 0', 87735 599,8 203,3

i .SPACING MODEL RHO FIELD RHO

. . . . ^ z z .7075 70,7

1.47 46,0 45,52,15 43,5 41,6

. 3 ,16 ....39,5 38,8'i •,,, 4,64 43,2 43,0j.- 6,91 . 43,1 43,5

13, 08- 50', 2 50,314.69 63,1 60,721,54 83,3 78,9-

• 3i, 62- .. 96,9 ' ' 99,3! • 45,42 ■ 106.4 113,0! : ;. . (58,13.: 105,2 103,0

100', 0(0 9874 97,2146,78 98,5 94,5.215,44 111,7 117,0 - -

I ’-V RMS, ERROR. ?r ' 2 , 7 8 1


123 . , .4 ’ .5

“ THICKNESS ELEV \ RHO THICK*RES THICK/RES 0.41 630.0 ,429.4 175.1 0.00095.43 678.7 \ 66.1 359,3

12.39 660.8 „ . 6?9,9 n’SIU11.75 613.5 r 13.0 211.4 0.65265B0.0 374.5

SPACING ‘ MODEL RHO FIELD RHO

1.001.472.153.16 •4.64 6.8110.0014.6321.5431.6246.4263.13100.00146.78215.44

Hi:!80.372.774.7 34.51.0 5.1135.9 170.4197.3203.4 134.1157.4 152.3177.9

loirS8 5.374.7 70.452.7 102.0137.0190.0195.0205.0185.0155.0152.0131.0RMS ERROR = 3.322


123

ITeT atTDM M3. 15, VES MO. 36LAYER THICKNESS ELEV RH 3 THICK»RES THICK/RES

1 . 0 . 4 12 5 . 4 2 :

' 3 1 3 . 1 9 1

6 8 3 , 06 7 8 . 76 6 3 . 9 :

4 2 9 . 8 5 6 , 1

6 3 3 . 0 .

1 7 5 , 2. 3 5 8 , 37 9 1 1 , 7

3', 0 0 0 9 3-, 0 8 2 3 " ) 3 U 0 2 2 3 -fit

4 4 . 6 35

6 1 7 . 66 0 2 . 4

7 . 2 3 6 8 . 8 \

3 3 . 3 3', 6 4 2 8 |

SPACl MB 1'. 30

MODEL RHO 1 8 8 . 6 ’

FIELD RHO 1 9 2 . 0

1 , 4 7 2> 15 3 . 1 6

1 1 3 , 58 3 . 37 2 . 7

1 3 8 , 08 5 , 87 4 . 7

4 . 6 4 6 . 8 1

13 ' . 00

74*,78 4 , 6

1 3 5 . 1

7 3 . 48 2 . 7

1 3 2 . 01 4 . 6 62 1 . 5 43 1 . 5 2

1 3 5 . 81 7 3 . 31 9 7 . 2

1 3 7 . 01 6 3 . 01 9 5 . 0

4 6 . 4 2 6 8 . 1 3

103-. 00

2 0 3 , 21 8 4 . 11 5 7 . 6

2 3 5 . 01 8 5 . 01 5 5 . 0

1 4 5 , 7 82 1 5 . 4 4

1 5 3 . 11 7 8 . 1

1 5 2 . 01 8 1 . 0

RMS. ERROR m 3 . 3 4 4

ITERATION NO. 15» VES NO. 37LAYER THICKNESS ELEV RHO THICKSRES THICK/RES. 1 0.68 678.0 233.8 162.6 0.00292 4.50 -• 675.3 43.2 194.3 0.10423 - 12.82 661.0 603.6 7737.4 0.02124 22.26 618.9 20.0 445.2 1.11305 545.9 . 201.1

SPACING MODEL RHO FIELD RHO1.00 178.0 181.01.47 123.5 125.02.15 32.4 3 2.93.16 58.4 59.54.54 54.6 54.66. SI 63.2 5 2.0'10.00 32.0 77.314.69 109.2 106.021.54 140.1 133.031.62 165.4 174.046. 4 2 175.0 19 6.068.13 160.2 164.0100.30 127.3 122.0146.78 • 104.7 94.5215.44 107.1 117.0RMS ERROR = 5.203


124

ITERATION >13. 1 5 , VES NO. 37

LAYER THICKNESS ELEV RHO THICK*RE5 THICK/RES1 0 . 6 5 2. 4 , 8 1 3 a . 95

6 7 8 . 0 6 7 5 . 86 6 0 . 1

2 4 1 . 0 4 6 . 1

4 2 5 . 0

1 5 8 . 42 2 1 . 5 4 0 2 . 4

3- ,0027 31, 1 34 4 0'. 0 0 2 2

4 1 2 , 4 4. 5 :-“ . 7 i 45«-6W .r

6 5 7 , 0 \ 6 1 6 , 1

v - r 5 9 1 . 7

6 0 0 . 05 . 8

: v 2 0 0 . 0

7 4 6 5 1 25 0 . 9

3', 0 2 0 7 1 , 0 9 4 7

SPACING MODEL RHO FIELD RHO. Udd

1 . 4 7 2 . 1 5 v

1 2 6 . 7 , 8 2 . 2

1 8 1 , 0 1 2 5 . 0

■ 8 2 . 93 . 1 6 4 . 6 4

• 6 . 8 1

5 9 , 95 6 . 36 4 . 1

5 9 . 55 4 . 6 6 2 . 0

■1 0> 0 01 4 . 6 82 1 . 5 4

8 1 . 91 0 8 . 51 3 9 . 1

7 7 . 31 8 6 . 01 3 3 . 0

•

3 1 . 6 24 6 . 4 26 8 . 1 3

1 6 5 , 51 7 5 . 41 6 0 . 2

1 7 4 . 01 9 6 . 01 6 4 . 0

i a a > 0 01 4 5 . 7 82 1 S . 4 4

1 2 8 . 11 0 5 . 01 0 7 . 3

1 2 2 . 09 4 . 5

1 1 7 . 0

RMS. ERROR 9- 5 . 3 4 7

ITERATION NO. 1 2 , VES NO. 38 \ A

...... .

LAYER THICKN1 r . 0 32 4.173 14.584 2 0 . 1 0

........5:;::. .•

ESS ELEV677.0 673.6 659.96 1 2 . 1

‘ — 546.2 _

SHQ THICK*RES 191.1 197.6 67.3 280.4726.3 10589.6 29.0 582.81 4 7 . 3

THICK/RcS0.00540.06190.02010.6930

SPACING MODEL RHO FIELD RHO1.00 177.1 174.01.47 158.9 164.02.15 131.2 129.03.16 104.4 105.04.64 92.4 91.46.31 100.5 102.010.00 . 127.0 128.014.68 166.5 16C.C21.54 210.3 203.031.62 245.1 253.046.42 252.3 271.068.13 220.9 216.0100.00 166.1 160.0 •

146.78 125.6 128.0215.44 117.0 117.0RMS EPRCR = 2.945


125

ITERATION MO, 9. VES NO*. 38

LAYER THICKNESS ELEV_______ RHO,_EHI£K_*RfS THICK/RESI : vT,.l . 1 , 0 3 6 7 7 , 0 - 1 9 1 . 3 1 9 6 , 9 3*,0054 •

2 4 , 2 1 6 7 3 . 6 v ^ 6 7 . 7 2 8 5 . 3 3 , 0 6 2 33 1 5 . 1 4 6 5 9 f _8_ 7 2 5 . 5 ___10&8.2,%_____ 3 - , 0 2 M . _4 5 , 4 5 6 1 3 . 1 7 . 3 - 3 8 . 2 3 , 7 7 9 75 5 9 2 . 2 1 6 4 . 2

SPACING MODEL RHO FIELD RHO _ U M ________ m l * _______ 1J4...0_

1 , 4 7 1 5 3 . 9 1 6 4 . 02 . 1 5 1 3 1 • 1 1 2 9 . 03 . 1 6 1 0 4 . 4 10 5 . 04 j 64- : - 9 2 , 5 ' ’ . ' : 9 1 . 4

V 6 . 8 1 1 0 0 , 4 1 0 2 . 01 3 . 0 0 1 2 6 . 7 1 2 8 . 01 4 , 6 8 1 6 6 , 2 1 6 0 . 02 1 , 5 . 4 2 1 0 , 2 2 0 3 , 0

3 1 , 6 2 2 4 5 . 4 2 5 3 , 04 6 , 4 2 2 5 3 , 2 2 7 1 , 06 8 , 1 3 2 2 1 . 6 2 1 6 , 0

1 0 3 y 00 1 6 5 . 8 1 6 0 . 01 4 6 , 7 8 1 2 4 . 7 1 2 8 . 02 1 5 . 4 4 1 1 7 . 8 U 7 . 0

RMS. ERROR s 2 . 9 1 6


126

ITERATION NO. 15, VES NO- 39LATER THICKNESS ELEV RHO TH1 0.35 675.0 854.2 .•2 . 1.32 673.9 66.33 2.78 669.5 940.74 5.62 660.4 185.65 7.77 642.0 920.16 - 5.35 616.5 14.0 • i7 598.9 229.2

SPACING MODEL RHO FIELD RHO1.00 . 237.0 237.01.47 126.5 126.32.15 109.2 110.13.16 135.9 133.14. 64 179.3 178.16.81 230.2 233.110.00 277.3 278.014.63 311.3 303.021.54 326.4 326.031.62 319.3 317.046.42 234.7 283.063.13 224.9 235.0100.00 175.4 166.0146.78 164.4 169.0RMS ERROR » 2.347

296.6 \ 88-4 2615.6 1042.5 7148.0 75.0

THICK/RES 0.0004 0.0198 0.0030- 0.0302 0.0084 0.3824

ITERATION NO. 15, VES NO. 39LAYER- THICKNESS ELEV- RHO THICK*RES THICK/RES.1: 0.35 675.0 352.4 296.2 0.00042 1.32 673.9 66.3 88.4 0.01933.. 2.77 669.5 943.8 2611.9 0.00294 5.60 - 660.4 185.6 1039.9 0.03025 7.62 642.1 920.0 7014.4 0.00336 13.29 617.0 34.0 452.0 0.39107 - 573.4 230.6

SPACING MODEL RHO FIELO RHO1.00 235.9 237.01.47 126.5 ■ 126.32.15 109.2 110.13.16 135.9 133.14.54 179.9 173.16.31 230.2 239.110.00 277.4 273.014.68 311.3 303.021.54 326.4 326.031.6 2 319.9 317.046.4 2 234.7 233.066.13 224.9 235.0100.00 ■175.4 166.0146.73 164.4 169.0

RMS ERROR.* 2.345


127

ITERATION NO. 15, VES NO. 40LAYER THICKNESS ELEV1 0.85 673.02 0.54 670.2

RHO THICK*RES THICK/RES505.9 427.6 0.001710.0 5.4 0.0540

3 11.814 13.345

66 8.5 629.7 585.9939.910.3352.0

11692.7143.60.01191.2398

SPACING1.001.472.153.16 4.64 6.8110.0014.6321.5431.6246.4268.13100.00146.73

MODEL RHO397.5285.9160.236.280.6108.6149.5198.7248.6282.7273.4227.0155.9115.1

ERROR = 1

FIELD RHO341.0342.4165.177.2 73.4109.0151.0204.0268.0234.0263.0226.0157.0115.0,435

ITERATION: NO. 1 5 , VES NO*. 41

LAYER, THICKNESS ELEV RHO THICK#RES THICK/RES . 1 1 . 2 9 6 7 5 , 0 2 5 4 . 1 328*. 8 3'. 0 0 5 1

.. 2 . 1 U 5 : . . 6 7 0 . 8 2 1 . 0 2 4 *r 2 3' .054B3 1 4 , 9 § : 6 6 7 , 0 8 4 0 , 0 1 2 5 5 5 . 7 3 - . 01784 4 , 9 9 * 6 1 7 , 9 1 1 . 0 5 4 . 8 3 , 4 5 3 8

_ 5 _____ :___ 631^6______ 252^0____________________________

SPA?ijl-S __.MQD_SLLRHQ: F I ELD RHO1 . 0 01 4 4 72 . 1 5

„ 2 3 7 , 0 2 1 1 . 5 1 6 6 r 3

2 3 3 . 02 1 0 . 0 1 7 3 . 0

3 . 1 6 1 1 5 . 3 1 1 5 . 04 . 6 4 9 0 . 1 8 7 . 16 . 8 1 1 0 3 . 1 1 0 3 . 0

1 0 . 0 0 1 3 9 . 2 1 4 5 . 01 4 . 6 8 1 8 6 . 2 1 8 9 . 02 1 . 5 4 2 3 7 . 1 2 3 2 . 03 1 . 5 2 2 7 8 . 9 2 6 6 . 04 6 . 4 2 2 9 2 . 2 2 9 5 . 06 8 . 1 3 2 6 5 . 2 2 8 0 . 0

1 0 0 , 0 0 2 1 4 . 9 2 1 3 . 01 4 6 . 7 8 1 8 1 . 5 1 7 6 . 02 1 5 . 4 4 1 8 3 . 2 1 8 9 . 0

RMS. ERROR =• 2 . S 5 4


128

i t e r a t i o n : m o * i s . ves n o . 42\

layer t h i c k n e s s elev ! 1 ' 0 , 7 7 6 7 0 . 0

2 0 . 8 2 6 7 5 . 5

RHO . THlCKftRES 9 7 . 3 7 5 . 3

1 8 4 . 1 1 5 1 . 1

THICK/RES 3', 038 3 31, 0 0 4 5

3 1 * 9 54 1 3 . 5 55 8 . 9 7

6 7 2 . 8 6 6 6 . 46 2 1 . 9

3 3 . 96 5 0 . 1

1 1 . 0 * /

6 6 . 3 8 8 3 5 1 9

96 L 6

3*. 0 5 7 7 3', 0 2 08 3 . 8 1 5 1

6 5 9 2 . 5 4 8 3 . 0

SPACING U M 1 ■ 47

MODEL .RHO 1 0 3 . 9 1 0 8 . 7 ,

FIELD RHO . 1 0 4 , 0

1 0 9 . 0I' 2 * 1 5

3 , 1 6 ! 4 . 6 4

1 0 2 * 9 : 9 3 . 2

1 0 8 . 0 • 1 8 6 , 8

9 1 . 4, 6 . 8 11 3 > 5 01 4 . 6 8

. 96*0 , 1 1 9 . 0 1 5 5 ; 3

, . 9 5 , 8 1 2 2 . 0 1 4 9 . 0

2 1 , 5 4 I ■ 3 1 . 6 2 ; ! 4 6 . 4 2

. . . . . 1 9 3 7 , . ..

2 2 1 ; 1 > •. • .-;2 2 1 i 6 ■

1 8 6 * 0 / ' 2 2 8 . 0 '

2 3 4 . 06 8 * 1 3

1 0 3 . 3 01 4 6 . 7 8

1 9 0 * 91 5 1 . 51 3 8 . 9

1 9 1 . 81 5 8 . 01 2 8 . 0

2 1 5 . 4 4 1 6 2 . 0 1 7 5 . 3

RMS. eRROR s: 3 . 858

ITERATION NO. 15. VES NO. 43 'LAYER THICKNESS ELEV RHO THICXvRES1 0.91 690.0 193.8 182.52 5.15 677.0 65.0 335.03 10.91- 660.1 600.0 6543.64 8.97 624.3 11.0 98.55 594.9 490.0

THICK/RES0.00460.07930.01820.8176

SPACING1.001.472.153.16 4.64 6.9110.0014.4321.3431.6246.4268.13100.00146.79215.44

•MODEL- RHO179.0154.7121.393.8 81.385.9103.3132.3 15 2.3133.1131.0156.5132.2 135. *»163.2

FIELD RHO176.0145.0115.0 99.9 93.2 94.0131.0123.0 1 5 ?■ . 0 17 9.0139.0169.0123.0122.0 189.0

RMS ERROR = 6.936


129

ERftTlOW MO. 15, \IE& NO. 44

yer thickness elev rho thiciures t h i c k/res1 a . 85 6 8 2 . 0 1 7 8 . 2 1 5 1 . 0 3 ' . 0 0 4 B2 \ 4 , 7 5 ' 1 1 1 . 6 7 * 4 v 1 3 . 1 5 :

6 7 9 , 26 6 3 . 6

■-•':'«f'625l3 ' . ■

3 1 . 75 4 5 . 6

l i . 0

1 5 0 . 6 6 3 6 7 . 2

1 4 4 1 6

3*. 1502 3', 0 2 1 4 i ; 1 9 5 1

5 ' • . 5 3 2 . 2si.\

4 8 3 . 2

SPACING MODEL RHO. FIELD; RHO1 , 0 0 " 1 4 8 * . 9 1 4 6 . 01 . 4 7 1 1 7 . 5 1 2 1 . 0...... ^ .

■ " " ' 7 9 . 0...... ....... ... . — ..m m .. — .»

3 > 1 6 5 1 . 5 5 0 , 54 : 6 4 4 2 ‘f 0 4 2 . 8 «

- 6 * 8 1 ^ 45>7 4 6 . 0 :1 3 : 0 0 5 8 . 5 5 6 . 3 *1 4 . 6 8 . 7 8 . 4 7 3 . 5 _2 1 . 5 4 1 0 2 . 1 9 8 . 33 1 . 6 2 1 2 4 . 1 1 3 0 . 04 6 . 4 2 1 3 6 . 4 _ 1 5 1 . 06 3 . 1 3 1 3 2 . 4 1 3 7 . 0

1 0 3 . 0 0 1 1 7 . 2 1 1 6 . 0I4£aj_8 . ... U 0 . 3 _ 8 7 . 82 1 5 . 4 4 1 2 7 . 3 1 4 6 . 0

M S i.£RR0.8,.sj 8j 321

ITERATION NO- 14, VES NO- 45LAYER

1• 234

56

THICKNESS ELEV 0-72 635-05.94 632.63.23 663-1.02 652.5.47 626.2611.6

*P*LXM MODEL RHO 715.21.47 493.42.15 274.83.16 150.74.64 111.46.81 100.510.00 94.214.63 92.221.54 97.231.62 102.846.42 100.06S.13 92.0100.00 92.0146.73 107.5

RHO THICK*RES THICK/RES969.1 699.7 0.0007101.8 605.0 0.058437.9 122.3 0.0352345.0 2766.3 0.0232:.6.0 26.8 0.7457250.0FIELD RHO712.0495.0277.0149.0111.0

102 .0 .94.091.198.9 102.099.1 93.590.9 103.0RMS ERROR = 1.031


130

ITERATION NO. 15, VES NO. 46LAYER THICKNESS ELEV RHO THICK*RES THICK/RES1 1.16 693.0 1081.0 125 8.4 0.00112 2.37 679.2 269.9 639.6 0.00633 19.55 671.4 40.0 742.0 0.46374 610.5 109.1

SPACING1.001.472.153.16 4.64 6.8110.0014.6821.5431.6246.4268.13100.00

MODEL RHO 1005.7897.1708.1477.5232.1151.6 78.551.447.5 51.860.6 71.582.3

FIELD RHO980.0930.0775.0430.0262.0 149.075.4 59.254.054.155.669.631.5RMS ERROR 6.794

ITERATION; VO, 5# VES N‘0, 47LAYER . T K i : « VESS ELEV RHO rH!CK#R2S THICK/RES

1 9 , 4 4 6 8 5 , 3 5 8 6 , 3 2 5 9 . 4 3 , 0 0 0 9• 7 1 3 . 0 3 6 8 3 . 5 5 2 . 4 5 2 4 . 3 3' . lH0fi - .

3 7 , 6 5 • 6 5 3 , 3 3 3 5 , 3 2 5 6 1 . 9 3 . 0 2 2 3 ;4 4 , 9 9 6 2 5 , 7 3 , 9 . 4 4 . 4 3 , 5 5 9 65 6 3 9 . 3 2 8 5 . 9

SPAOl.VS MODEL RHO FIELD R4D• - . 1 . 3 0 2 5 3 . 3 , 2 4 1 , 0

r.- 1 , 4 7 1 2 8 , 5 1 4 3 , 0... 2b15 7 1 . 4 \ 6 5 . 33 . 1 6 5 7 , 1 5 5 , 44 , 6 4 . 5 4 , 8 5 4 , 8

•• 6 . 8 1 , _ 5 5 . 5 5 8 . 31 3 , 3 0 5 9 , 0 6 1 , 71 4 , 6 8 • 6 6 , 7 6 8 , 2

...' 2 1 . 5 4 V S'-ytfr 7 3 ; 3 V . - : 7 4 . 7. 3 1 , 5 2 8 9 . 4 8 5 , 7 -

• 4 6 , 4 2 9 5 , 1 9 9 , 16 3 . 1 3 9 7 . 4 9 7 . 2

1 0 3 , 1 ? 5 , 5 1 3 5 , 01 4 5 , 7 8 1 2 5 , 3 1 2 2 , 3

... . 1 1 5 . 4 4 . L*ii* . 1 63,J5

RMS. ERROR s 4 . 4 4 ? .


131

ITERATION NO. 6» VES NO. 47LAYER THICKNESS ELEV RHO THICK*RES THICK/RES1 : : -O.A4 - 685.0 - ' 586.0 259.4 0.0008. 2 9.96 683.5 52.4 521.9 0.18993 7.27 650.9 334.0 2428.4 0.02134 14.49 627.0 25.8 373.8 0.5618

• ---579.5 ^ — 283.9 -

SPACING MODEL RHO - FIELD RHO1.00 .250.4- ----241.0 -1.47 123.5 140.02.15 71.3 65.33.16 57.1 55.44.64 54.8 54.86.81 55.5 58. 310.00 59.0 61.714.68 66.7 63.221.54 79.4 74.7 ~31.62 89.3 86.746.42 95.0 99.165.13 97.4 97.2100.00 - 105.6 105.0146.78 125.8 122.0215.44 154.6 160.0

RMS ERROR * 4.447

ITERATION NO. IS, VES NO. 48LAYER. THICKNESS ELEV RHO THICK*RSS1 1.03 633.3 873.2 901.12 3.15 679.6 74.2 234.03 4.57 -669.3- .. 7.0 - 32.04 11.46 654.3 275.0 3152.15 29.24 616.7 35.1 1027.7-Av. 520.7 :_ _200.0 ...

SPACING MODEL RHO FIELD RHO \1.00 763.9 753.01.47~ 622.8“ .. 643.0 • ....2.1-5 411.7 406.03.16* 209.4 211.0.. . 4.64 93.9 92.56 . 31^.---- 48.0 ---- 48.0*". • ..•■•••10.00 27. 5 28.5 ■ .. V ■:

• 14.68 22.0 20.321.54 27.0 24.3...31.52 — ---- 35.0 ' .... 38-7 ....46.42 46.3 54.153.13 56.7 52.3

100.00 66.3 62.7

THICK/RES 0.0012 0.0425 - 0.6532 • 0.0417 0.8321

RMS ERROR a 5.392


ITERATION NO. .15* .' VES NO. 43 .LAYER THICKNESS ELEV RHO1 1.02 T 4 683.0 872.4

2 ^3.13 .J^:679.6/-v;;^:-:76.7, . - . 3 . . . , . , 5 . 3 4 6 8 9 . 4 . / 7 . 6• 4: • -12.21 631.9 - -V ;'275.0.."S ,6.00 .?■» 611.8..... 14*9

6 "■ ■ ■:■■ ■ ■ ■ ' > 592.1.•• vr.r - .300.0

132

THICKSRES 893.2 240.0 • 40.43358.7 . 89.1

.'THICKER ESa . 0.0012 .0.0408 0.7039. r, 0.0444 -7- .. 0.4038 • .

SPACING MODEL RHO1.00 .761.71.47 619.72.15 408.33.16 203.54.64 94.76.81 48.710.00 27.514.69 21.2.I 21.54 25.831.62 34.946.42 46.363.13 59.7100.00 76.0

FIELD RHO758.0643.0406.0211.092.543.028.5 . 20.324.839.754.152.8 62.7

. 7-ssker-r

RMS ERROR = 3.789

i t f r .m i O'J *Jo . 1 5 , VES rfO. 49

LA/SR rHKX'IESS ELEV RH? THTC1 1 , 7 5 63 3 . 1 2 7 3 . 37 "19 ,77"" 6 7 7 , 7 3 7 . 33 6J9.4 3 0 3 . 3

SPACING MODEL RHO FIELD RMO1 , 9 0 2 6 2 , 6 2 5 9 , 91 . 4 / .........2 4 3 , 9 2 4 5 . 92 . 1 5 • 2 1 7 , 9 2 3 7 , 93 . 1 6 1 6 4 . 5 1 5 3 . 9-------- 4 - 5-4 - - 1 3 2 , 7 - ---------- 9 7 . 7 ' "6 . 3 1 6 3 , 1 6 4 , 4 ^

1 3 , 30 4 4 . 3 5 1 , 31 4 . 6 b 4 1 , 6 47 7 92 1 , 5 4 4 5 , * 4 7 , 53 1 . 5 2 5 4 . 2 5 4 . 34 S . 42 7 <5.6 6 7 , 86 3 , 1 3 9 3 . 7 9 1 , 9

1 2 3 . 3 3 122.'*' 1 1 3 . 0146.70 I 3 '.. I 1 5 2 , <>

<*RSS thick/res 4 7 4 , ̂ 3-. 07657 3 1 . -t--------3- ,514? ’

P H 5. i.R-JCR = 6,877


133

ITERATION NO. 12# VES NO. 50LAYER THICKNESS ELEV RHO1 0.21 673.0 483.02 2.34 677.3 36.33 4.79 668.0 100.14 15.69 652.3 20.05 597.5 500.1

THICK*RES 103.0 1 04. 6 479.4 333.9

THICK/RES0.00040.07700.04730.3347

SPACING1.001.472.153.16 4.64 6.S110 .0014.6321.543 1 . 6 246.4263.13

100.00146.73215.44

EL RHO FIELD RHO54.0 54.441.0 39.639.5 40.241.1 40.145.2 44.350.9 51.355.0 56.053.9 54.747.3 45.743.2 44.947.3 47.363.6 63.533.1 24.6120.7 123.0161.6 160.0RMS ERROR = 2.350


Appendix D

Archie's Law Calculations

134


135

Vail Addraaa

Archie's

Spaclf. Cond. Dooaatic Vail H,0

Cumhoa/ea)

Law Input

RaalatlvltyH O(i*»)

Data

RaaiatlvityFran

(jl?M )12303 14 IH 350 18.2 92.512320 14 IH 375 17.4 88.41303 Laoaard 660 15.2 77.212160 14 IH 700 14.3 72.61457 Laonard 12124 14 IH

725 13.8 70.1

1383 Laonard 740 13.5 68.61577 Laonard 760 13.2 67.11533 Laonard 810 12.3 62.51475 Laonard 830 12.0 61.012150 14 IH 830 11.8 59.912187 14 IH 860 11.6 58.91424 Laonard 900 11.1 56.41423 Laonard 960 10.4 52.812171 14 IH 990 10.1 51.41432, 1426, and 1433 Laonard

1000 10.0 50.8

12155 14 IH 1100 9.1 46.21523, 1345 and 1723 Laonard 12133 14 IH

1200 8.3 42.2

12109 14 IH 1400 7.1 36.11501, 1542 and 1587 Laonard

1600 6.3 32.0

1683 Laonard and 12115 14 IH

1700 3.9 30.0

1428 and 1310 Laonard

1800 5.6 28.4

1463 Laonard 1900 5.3 26.91500 and 1451 Laonard

2000 5.0 25.4

1484 Laonard 2600 3.8 19.8

Archla'a Law

whara / “ poroalty) • 30X


Appendix E

Geoelectric Sections B, C, F,G, H, and I

136


137

-SJ r

a

>1

oz<JiUU

oz<e i

W!|»!■!»

za0

o•Io

1 1 A I1 V IS N V IW IA O IV 1111


OE

OE

IEC

IIMC

S

EC

TIO

N

138

IM t> O

S 10 > +

III <0 > +

ozoz3o

<u

<u

z<1(1zououiz

<>

W VO fc

H A I 1 V3S M V 3 W 3A09V 1333


GiO

HfC

ltlC

S

EC

TIO

N

139


GE

OC

II C

IK

1C S

EC

TIO

N

140

11AI1 V i l N V 1W 1 A O IV l i l i


141

IS

s:

3 M

ftn

mmm

»3 I *

f f ? f ? i § 3 2 S fJ--- 1__1___ I__IH » n i n n v iw ia o iv t i n


OIQ

ItK

IHC

1I

C>

IPX

142

mmst

; •

5 •>

Mm. >

*A••

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o o O o o• • • • •I I i T i J I

1IAI1 V II NVIW IA O IV I I I !


BIBLIOGRAPHY

Bisdorf, R. J. (1983a). Schlumberger soundings nearNewberry Caldera, Oregon. (United States Geological Survey Open-File Report, 83-825). Washington, DC: U. S. GovernmentPrinting Office, 1-51.

Bisdorf, R. J. (1983b). Schlumberger soundings on the Snake River Plain near Nampa, Idaho. (United States Geological Survey Open-File Report, 83-412). Washington, DC: U. S.Government Printing Office, 1-56.

Bisdorf, R. J. (1985). Electrical techniques for engineering applications. Bulletin of the Association of Engineering Geologists, 22, 421-433.

Cartwright, K., & McCoraas, M. R. (1968). Geophysical survey in the vicinity of sanitary landfills in northeastern Illinois. Ground Water, 16, 23-30.

Davis, P. A. (1979). INVERSE [computer program], St. Paul, Minnesota: Minnesota Geological Survey. (Interpretation of resistivity sounding data: Computer programs for solutions tothe forward and inverse problems, Information Circular 17).

Davis, S. N., & DeWiest, R. J. M. (1966). Hydrogeology New York: Wiley.

Dobrin, M. B. (1960). Introduction to geophysical prospecting.(2nd ed.), New York: McGraw-Hill.

Dorr, J. A., & Eschman, D. F. (1970). Geology of Michigan. Ann Arbor: University of Michigan Press.

Driscoll, F.G., (1986). Groundwater and Wells. (2nd ed.),St. Paul: Johnson Division.

Fink, W. B., & Aulenbach, D. B. (1974). Protracted recharge of treated sewage into sand part II: Tracing the flow of contaminated ground water with a resistivity survey. Ground Water, 12, 219-223.

Fretwell, J. D., & Stewart, M. T. (1981). Resistivity study of coastal karst terrain, FL. Ground Water, 19, 156-161.

Hamrick, R. J. (1978). Dolomitization patterns in the Walker Oil Field, Kent and Ottawa Counties, Michigan. Unpublishedmaster's thesis, Michigan State University, Lansing, MI.

143


Herold, J. E. (1984). The use of oil field brine on Michiganroadways■ Lansing: Michigan Department of NaturalResources, Geological Survey Division.

Huffman, G. C. (1977). Ground water data for Michigan. (United States Geological Survey Open-File Report, 79-332). Wa Washington, DC: U. S. Government Printing Office, 1-75.

Kunetz, G. (1966). Principles of direct current resistivityprospecting. Berlin: Gebruder Borntraeger.

Kwader, T. (1985). Surface borehole geophysical methods inground water investigations second national conference andexposition. National Water Well Association Conference Proceedings. Denver, 833-841.

Leverett, F., & Taylor, F. B. (1915). Pleistocene of Indiana and Michigan, and the history of the Great Lakes. (United States Geological Survey Monograph, 53). Washington, DC:U. S. Government Printing Office, 1-529.

Lowden, J. (1964). A combined geologic and gravity analysis ofWalker Oil, Michigan. Unpublished master's thesis, Michigan State University, Lansing, MI.

Meisel, K. E. (1985). The use of electrical resistivity todelineate a brine contamination plume in the Walker Oil Field,Kent County, Michigan. Unpublished master's thesis, Western Michigan University, Kalamazoo, MI.

Merrick, N. P. (1977). A computer program for the inversion of schlumberger sounding curves in the apparent resistivity domain. Hydrogeological Report 1977. Sydney: New SouthWales Water Resources Commission.

Michigan Department of Natural Resources, Geological SurveyDivision. (1983). Michigan's oil and gas fields,1981: Annual statistical summary, 36.

Mooney, H. M. (1980). Handbook of engineering geophysics. 2 ,

Electrical resistivity. Minneapolis: Bison Instruments,pp. 27.1-34.19.

Newcombe, R. B. (1940). Developments in Michigan during 1939. American Association of Petroleum Geologists Bulletin, 24, 974-993.

Passero, R. N. & Sauck, W.A. (1988). Groundwater contamination studies in the Walker Oil Field, Kent and Ottawa counties,MI. Unpublished manuscript, Western Michigan University,Geology Department, Kalamazoo, MI.


Stollar, R. L., & Roux, P. (1975). Earth resistivity surveys - a method for defining groundwater contamination. Ground Water. 13, 145-150.

Stramel, G. J., Wisler, C. 0., & Laird, L. B. (1954). Water resources of the Grand River area, Michigan. Michigan Department of Natural Resources. (Geological Survey Division, Circular 323). Lansing: Michigan Department ofNatural Resources, 1-40.

Swartz, J. H. (1939). Part II - Geophysical Investigations in the Hawaiian Islands. Transactions of the American Geophysical Union, 20, 292-298.

Telford, W. M., Geldart, L. P., Sheriff, R. E., & Keys, D. A. (1976). Applied geophysics. New York: Cambridge University Press.

Ten Brink, N. W. (1975). Surficial geology and landforms of east central Ottawa County, Michigan. Unpublished report, Grand Valley State College, Allendale, MI.

United States Environmental Protection Agency. (1981). Hydrogeology for underground injection control in Michigan: part 1. Underground Injection Project. Kalamazoo: Western Michigan University, United States Environmental Protection Agency.

Wagner, T. A. (1988). Ground water quality in the Walker Oil Field. Unpublished master's thesis, Western Michigan University, Kalamazoo, MI.

Warner, D. L. (1969). Preliminary field studies using electrical resistivity measurements for delineating zones of contaminated ground water. Ground Water, 7_, 9-16.

Westjohn, D. 1987, United States Geological Survey, personal communication.

Zohdy, A. A. R. (1965), Geoelectrical and seismic refraction investigations near San Jose, California. Ground Water, 3 41-48.

Zohdy, A. A. R., Eaton, G.P., & Maybey, D.R. (1974). Application of surface geophysics to ground-water investigations.IN Techniques of Water-Resources Investigations of the United States Geological Survey, (Book 2, Chapter Dl), Washington DC: U. S. Geological Survey, 1-59.


PLEASE NOTE

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The following map or chart has been refilmed in its entirety at the end of this dissertation

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NW

MODELr- 700VES VESVES

498- 680320

26*- 660

24*

- 640 16580

177- 620

- 600

L 580

276 171

MODEL B700

- 680 33

- 660 82

225640

- 620164

600 108191

- 560Reproduced with permission of the copyright owner. Further reproduction prohibited without permission.

GEOELECTRIC SECTION A

VES VES SB OWR VES VES WWR

2b 2a 4 7695 1b 1a 12180

- 6 5 -11239*

161

510700

298

50 m g/l

200216 151

263

246161 128188

37

281 74?266 288

V

\ 132


OWR VES VES WWR VES OWR

7695 12180- 6 5 -112 6011J*55*161 243

24700

390

440216 151

128

117

305281

74?

186


; SAND m SAND AND GRAVEL BEDROCK

320 RESISTIVITY (ohm-metor) 50 mg/t CHLORIDE CONCENTRATK

VES VERTICAL ELECTRICAL SOUNDINGS 5 L STATIC WATER LEVELS


H SANDY CLAY— — •

— — • CLAY SCREENED INTERVAL 1 I IH—I |0 115

FEET

'tTRATION SB SOIL BORING OWR OIL WELL RECORD WWR WATER WELL RECOR)

LS * RESISTIVITY VALUES HELD CONSTANT

\


NL WELL RECORD WWR WATER WELL RECOR) ^ ,

PLATE 1


PLEASE NOTE:


LEFT TO RIG H T, TOP TO BO TTO M , W ITH SMALL OVERLAPS






University M icrofilm s International


V /

2UJ

<UJ</>

<UJ

£oCD<I— UJ UJu.

NW

r- 700

- 680

- 660

- 640

- 620

600

r- 580

- 560

- 540

520

r 700

r- 680

- 660

MODEL A

VES49

MODEL B

OWR9851

VES48

VES47

SB3

WWR1587

586270

52

37335

275 352 mg

300286

300

270 74


GEOELECTRIC SECTION D

WWR VES VES WWR VES OWR VES WWR VES1587 33 15 1451 14 13447 13 1501 12

452243-

40* 454245

400 365650 660

352 mg/l 8*

495 mg/l 32*391 m g/l

145

235 125

165


VES OWR WWR 10 9385 1435

WWR1501

WWR1475

WWR1463

VES VES

2796

^ 5 ^ ~.=?6r:

82-408- 33

400■5Z.150*

100660

■U3 m a/l 165 m g/l515 mg/l32*391 m g/l

207

279I

300

165*


i- 700 MODEL B

2a2V )

z<ll]2£om<til

- 680

- 660

- 640

- 620

- 600

h 580

- 560

- 540

- 520

~H7T270 74

37*

275 334

300

284

S5E

200

*- 500

SAND m SAND AND GRAVEL o°o° GRAVEL

270 RESISTIVITY (ohm-meter) 352 m g/l CHLORIDE CONCENT

VES VERTICAL ELECTRICAL SOUNDINGS SZ. STATIC WATER LEVEL


1471

45451 650

373321

2. 660

25*

53

30 136258

125164

VEL SANDY CLAY CLAY GRAVELLY CLAY BEDROCK SCREENED INTERVAL

ORIDE CONCENTRATION SB SOIL BORING OWR OIL WELL RECORD WWR WATER WELL RECORD

C WATER LEVELS * RESISTIVITY VALUES HELD CONSTANT


ZEST2796'

300■2.

165*

660

25*

53228

INTERVAL

WELL RECORD

I M I- I IoFEET 85

PLATE 2


PLEASE NOTE


LEFT TO R IG H T, TOP TO BO TTO M , W ITH SMALL OVERLAPS






University M icrofilm s International


ET AB

OVE

MEAN

SE

A LE

VEL

| FE

ET

ABOV

E ME

AN

SEA

LEVE

L

NW

r- 680

- 660

I - 640

- 620

- 600

- 580

l - 680

- 660

- 640

- 620

U 600

MODEL A VES 39

920

14*

228

MODEL B

920

34*

VES38

164

29

VES37

200

20*


241191

68425

186

600726

239—191-

68

186

725 604

/

GEOELECTRIC SECTION E

VES36

369

WWR1484

VES35

VES31

WWR1430

VES24

SB2

VES25

319"85'354' 48

25* 353866

100

140140600 406

itsy722 mg/l •411 mg/l 100

287205

200

2088429!

66 38 5 6

I ' S L

140140610 406

18*

/30*


VESVESWWRVESVESVES

m75131920 5840{

750318112

10099I

138 mg/l83132

12!

669•3951 B r

750339112100

6683125132

100


SE

VESVESWWR 1432pSI ̂ 4 7 0 -

VES27

■395751

408750318

112

998

138 mg/l 66132 125

669•395 —5132

408750339

112

99883

125132


\

MODEL B

2y2V )

2<LU3E2oCD<LU

r - 680

- 660

- 640

- 620

- 600

- 580

- 560

* - 540

920

34*

29

239—191—

186

725 604

20*

201164


. \

88

323810C

140140610 406

29*18*

375 200

30*101

205

287

SAND SAND AND GRAVEL SANDY CLAY CLAY 3 5 GRAVELLY CLAY

8 54 RESISTIVITY (ohm-meter) 722 mg/1 CHLORIDE CONCENTRATION SB SOIL BORING

VIS VERTICAL ELECTRICAL SOUNDINGS 3 . STATIC WATER LEVELS * RESISTIVITY VALUES HELD CONSTANT


\

665■395 ------

32271£F

750339112100

83

13245

100

SCREENED INTERVAL

WWR WATER WELL RECORD

I I I I I IFEET 85

TANT


■395 _51

408750339

998

6683

125

FEET

PLATE 3


VNW

83a$

680

- 640

620

- 600

L 580

660

660

- 600

- 560

I- 540

I

MOOEL B

\ / \ /

MOOa AVES3 498"1767^^=^

GEOELECTRIC SEC’

VES2b

-k e h e i26* 46

296165

177

263276 171

164

191

266

108

91

SANO AND GRAVEL BEDROCKp

'M| SANDY CLAY

320 RESISTIVITY (ohm -m atar) 30 m g /l CHLORIDE CONCENTRATION SB SOIL B

VES VERTICAL ELECTRICAL SOUNDINGS H. STATIC WATER LEVELS • RESISTIVITY VAL

|1334190 © 1988 KOEW


GEOELECTRIC SECTION A

VES VES WWR

la 12180 --

VESVES OWR

7605VES

112

55*161 243ft*510 TO— Wjj

700206411 73mj/1 390

200 440216 151

263

161 246 128188

117

37305

2B174T266 288

186

132 630

SCREENED INTERVALCLAY

0 115FEET

WATER WELL RECOR)SB SOIL BORING OWR OIL WELL RECORD

PLATE« RESISTIVITY VALUES HELD CONSTANT

388 KOEHLER, JANET A.


VNW

i

- 960

- 940

U00EL A

VES40 OWR6651

VES46

VES47

S8 WWR VES3 1667 33

GEOELECTRIC SECTION D

VES VNffi15 1451

VES14

•452'

40* 42270

400ISZ. 6S<

335275 495 mg/1

235 122300

286 165

300

2•s

o9

- 520

270

451

321

3 7*

275 25*334

30020 30 258

35

164

200

2I I I SAND H H I SAND AND GRAVEL p»3 j| CRAW- [g » j| SANDY CLAY CUY CRAWLLY d

270 RESSTM7Y (d u n - lM la r) 332 mg/l CHLORIDE CONCENTRATION

VES VERTICAL ELECTRICAL SOUNDINGS SL STATIC WATER LEVELS • RESISTIVITY VALUES HELD CONSTANT

1334190 (c )l988 KOEH


ON Dve s cm14 13447

VES13

VES12

WAR1475

VES WVffi11 1463

VES OWR WVW 10 9385 1435

•82—.

33r-475.

400150*3656S0 100

-113 m g/l 115 m g/l22m g/l 391 m g /l

207145

125

650 ■2.373 165*

660

25*

228

136

125

GRAVELLY CLAY = BEDROCK W M SCREENED INTERVAL |-i ih- io

FIET

OWR OIL WELL RECORD WAR WATER WELL RECORD PLATE 20 0 CONSTANT

KOEHLER, JANET A.


FEET

AB

OVE

MEAN

SE

A LE

VEL

I FE

ET

ABOV

E ME

AN

SEA

LEVE

L

GEOELECTRIC SECTION E

fm SAND AND GRAVEL SANDY CUY

054 FESSnvmr (ohm-m«t«r)

3 . STATIC WATER LEVELS

1334190 ©1988 KOEHLEF


TRIC SECTION E

VESVESVES

1432

143075t*

20400

3928* 790

310112

too

140

130 mg/1

132 129

'MO-

408

790112

140

132

30*

100

105

287

r > 3 clay p q g gravelly c lay t s screened interval i-i-i- 1110 89

JONCENTRATICN SB SOIL BORJNO WVfi WATER HELL RECORD

LEVELS • RESISTIVITY VALUES HELD CONSTANT PLATE 3

KOEHLER, JANET A.


electrical resistivity as an approach to evaluating brine

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