computer aided interpretation of geophysical logs: development of a 3-d lithologic model for uranium...
TRANSCRIPT
Computer Aided Interpretation of Geophysical Logs: Development of a 3-D Lithologic Model
for Uranium Roll-Front Deposits
U2009 Global Uranium Symposium
May 11th, 2009Keystone, Colorado
Presented by:
Shawn Leppert Leppert Associates
Mike Hawks WildHorse Energy, Inc.
Mike Williams Leppert Associates
Robert ClarkAATA International, Inc.
What About U?Geophysics to Hydrostratigraphy
In the Current U.S Regulatory Environment - To Obtain a Permit for the Development of a Uranium In-Situ Recovery (ISR) Mine - Groundwater Flow must be Thoroughly Understood.
In the Current U.S Economic Environment - Mine Operations must be Optimized to Maximize the Mass of Uranium Ore Recovered with Respect to the Energy and Expense Required to Achieve that Recovery (Lixiviant Delivery and Fluid Recovery).
One Approach to Meeting these Two Requirements is to Develop a Detailed Hydrogeologic Conceptual Model to Assist in the Decision Making Process.
Many Uranium Roll-Front Ore Bodies are Found in Relatively Complex Hydrogeologic Environments
Cost of Hydrologic Characterization in Complex Subsurface Environment can be Expensive.
A Means for Reducing Those Costs is to Extract as Much Information as Possible from Existing Data - One Source of Data are Historical Geophysical Logs.
What About U?
Reports/Permits
Geochemistry
Hydrology
Geology
Quantitative Model
Geochemical Table (Static)
Well Construction Tables (static)
GW Quality Tables (dynamic)
Hydrostratigraphy Tables (static)
Hydrologic Tables (dynamic)
Event Tables (dynamic)
Electronic Database
Hydraulic Property Estimation
LS5011M
LS5012M
LS5013M
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0.5
0.1
0.05
0.01
0.005
0.001
0.0005
0.0001
Legend
Lost SoldierArea of Interest
Drawn by: MAW02/23/07PotSurf.lpk
N
Final LineSteady State
Well
Fraction ofInjection Material
Lixiviant Delivery & Recovery System Design
System Performance Monitoring
Quantitative Hydrogeologic Decision Framework
Data Evaluation Decision
Pilot Tests & Additional Characterization
ReclamationGeophysical
What About U?Geology to Hydrostratigraphy
Targeted Uranium Deposits are Located in Fremont County, Wyoming
Preeminent Geologic Conceptual Model for the Area Developed by the USGS
Geologic Map and Sections Showing Areal Distribution of Tertiary Rocks Near the Southeastern Terminus of the Wind River Range, Fremont and Sweetwater Counties, Wyoming (N.M. Denson and G.N. Pipiringos. 1974)
What About U?Geology to Hydrostratigraphy
Targeted Uranium Claim Site
Claim Site
What About U?Geology to Hydrostratigraphy
Targeted Uranium Claim Site
Primary Groundwater-Bearing Units of Interest:
Arikaree Formation (Ta; Lower Miocene)
Bridger Formation (Tbr; Upper Eocene)
Green River Formation – Both Upper & Lower Laney Members (Tgul, Tgll; Lower Eocene)
Battle Springs Formation (Tbr; Lower Eocene)
What About U?Geology to Hydrostratigraphy
Targeted Uranium Claim Site
Primary Groundwater-Bearing Units of Interest:
Geologic Structure May be a Very Important Control on the Movement of Groundwater
Structure Contours for Arikaree Formation
Horse Track Anticline
Numerous Normal Faults
DU
DU
DUU
D
DUD
U
Horse Track Anticline
Flattop Fault
What About U?Geology to Hydrostratigraphy
Targeted Uranium Claim Site
Primary Groundwater-Bearing Units of Interest:
Geologic Structure May be a Very Important Control on the Movement of Groundwater
Define the Groundwater Basin Which the Targeted ISL Mine Would be Located
What About U?Geology to Hydrostratigraphy
Targeted Uranium Claim Site
Primary Groundwater-Bearing Units of Interest:
Geologic Structure May be a Very Important Control on the Movement of Groundwater
Define the Groundwater Basin Which the Targeted ISL Mine Would be Located
What About U?Geology to Hydrostratigraphy
Targeted Uranium Claim Site
Primary Groundwater-Bearing Units of Interest:
Geologic Structure May be a Very Important Control on the Movement of Groundwater
Define the Groundwater Basin Which the Targeted ISL Mine Would be Located
What About U?Geology to Hydrostratigraphy
Targeted Uranium Claim Site
Primary Groundwater-Bearing Units of Interest:
Geologic Structure May be a Very Important Control on the Movement of Groundwater
Define the Groundwater Basin Which the Targeted ISL Mine Would be Located
What About U?Geophysical Data - Hydrostratigraphy
Geophysical Data are Routinely Collected for Uranium Exploration Borings
4 Common Historical Types of Data Acquired
Often there are Significant Quantities of Historical Data as Well as New Exploration Data Uranium Exploration in 1950’s, 1960’s and 1970’s
Single Point Resistance Logs **
Gamma Logs *
SP Logs
Neutron Logs
Single Point Resistance Logs have Potential for Delineating Relative Lithology
Measures the Electical Resistance Between an Electrode Placed at the Surface and a one placed within a Boring
What About U?Geophysical Data - Hydrostratigraphy
Data Calibration InterpretationSignal Analysis Tool
Digitized Geophysical
Logs
Major Geologic Unit Picks
Boring Locations Develop a Signal Analysis Tool which has both Flexibility and Calibration Capabilities
Evaluate Uncertainties and Limitations of Site Data
Calibrate the Signal Analysis by Leveraging Experienced Geologists Interpretation
Signal Analysis
Reproduces Geologist’s
Interpretation
Develop Local Hydrostratigraphy Model from Signal Analysis and Perform Additional Checks
Adjustments Required
All Information has been Extracted from Data for the Hydrostratigraphic Model
What About U?Geophysical Data
Geophysical DataBoring Data
• Nearly 1000 Borings
• Surveyed Coordinates
• Surveyed Ground Surface Elevation
• Geophysical Logging Data
• Data Compiled into a Relational Database.
What About U?Geophysical Data
Geophysical Datao Boring Data
Digitize Logs
• Digitize to 2.0 foot Precision - Capture Peaks and Troughs
• Scaled
• Data Compiled into a Relational Database
What About U?Geophysical Data
Geophysical Datao Boring Data
Geologic Units
o Digitize Logs
• Geologist Evaluated each Available Geophysical Log and Picked the Likely Geologic Unit Contacts
• Geologic Unit Picks were Integrated into the Groundwater Basin Scale Hydrostratigraphic Conceptual Model
• Data Compiled into a Relational Database
What About U?Signal Analysis Tool Development
Geophysical Data
Signal Analysis Tool Development
o Boring Data
o Geologic Units
o Digitize Logs
Smooth Noise
• For each point, pick the N points on either side value to be average of all 2N+1 points
• Depends on Calibration
• Repeat Smoothing Algorithm as Appropriate
• Signals Can be Quite Noisy
What About U?Signal Analysis Tool Development
Geophysical Data
Signal Analysis Tool Development
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
Filter Drift
• Ignore Peaks and Troughs
• Adjust Smoothed Signal Based on Regression
• Wireline Tool Signal can Drift as it is getting Lowered in the Boring
• Linear Regression Analysis
What About U?Signal Analysis Tool Development
Geophysical Data
Signal Analysis Tool Development
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
Peaks/Troughs
o Filter Drift
• Slope of the Signal
• Use a Five Point Estimate of the First Derivative
What About U?Signal Analysis Tool Development
Geophysical Data
Signal Analysis Tool Development
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
o Peaks/Troughs
o Filter Drift
Trivial Peaks
• Depends on Calibration with Geologist Picks
• If a Signal Peak is Relatively Small Eliminate from Consideration
Minor Peaks can be Removed
What About U?Signal Analysis Tool Development
Geophysical Data
Signal Analysis Tool Development
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
o Peaks/Troughs
o Filter Drift
o Trivial Peaks
Group Peaks
• Group Peaks from the Same Signal Response
Group Peaks from the Same
Signal Response
What About U?Signal Analysis Tool Development
Geophysical Data
Signal Analysis Tool Development
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
o Peaks/Troughs
o Filter Drift
o Trivial Peaks
Peak Width
o Group Peaks
• Slope of the Slope of the Signal
• Use a Five Point Estimate of the Second Derivative
• Geologist Picks are not this Mechanical
What About U?Signal Analysis Tool Development
Geophysical Data
Signal Analysis Tool Development
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
o Peaks/Troughs
o Filter Drift
o Trivial Peaks
o Peak Width
o Group Peaks
Peak Magnitude
• Claystone/Siltstone
• Correlate Peak Magnitude with Lithologic Material
• Silty Sandstone
• Sandstone
Silty Sandstone
Sandstone
Claystone
What About U?Signal Analysis Calibration
Geophysical Data
Signal Analysis Tool Development
Calibration
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
o Peaks/Troughs
o Filter Drift
o Trivial Peaks
o Peak Width
o Group Peaks
o Peak Magnitude
Geologist Picks• Experienced
Geologists Examined 18 Diagnostic logs and Made Picks
• Used for Calibration
What About U?Signal Analysis Calibration
Geophysical Data
Signal Analysis Tool Development
Calibration
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
o Peaks/Troughs
o Filter Drift
o Trivial Peaks
o Peak Width
o Group Peaks
o Peak Magnitude
Geologist Picks• Experienced
Geologists Examined 18 Diagnostic logs and Made Picks
• Used for Calibration
What About U?Geophysical Data - Hydrostratigraphy
Geophysical Data
Signal Analysis Tool Development
Calibration
Results
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
o Peaks/Troughs
o Filter Drift
o Trivial Peaks
o Peak Width
o Group Peaks
o Peak Magnitude
o Geologist Pics
Lithology within Boring
What About U?Geophysical Data - Hydrostratigraphy
Geophysical Data
Signal Analysis Tool Development
Calibration
Results
o Boring Data
o Geologic Units
o Digitize Logs
o Smooth Noise
o Peaks/Troughs
o Filter Drift
o Trivial Peaks
o Peak Width
o Group Peaks
o Peak Magnitude
o Geologist Pics
What About U?Conclusions
There can be a Wealth of Valuable Hydrogeologic Information Buried in Historical Geophysical Logs.
Using Relatively Simple Signal Analysis Techniques, this Information can be Cost-Effectively Extracted.
These Data can be Incorporated into a Hydrogeologic Model to Enhance our Understanding of the Hydrology within an Mine Site and Assist in Effective ISR of Uranium Ore.
What About U?End