geol 553 lecture 3; subsurface analysis geol 553: marine sediments university of south carolina fall...
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GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553: GEOL 553: Marine SedimentsMarine SedimentsUniversity of South CarolinaUniversity of South Carolina
Fall 2005Fall 2005
Professor Chris KendallProfessor Chris KendallEWS 304 EWS 304
[email protected] [email protected] 777.2410777.2410
The Tools of Subsurface AnalysisThe Tools of Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
The Tools of Subsurface The Tools of Subsurface AnalysisAnalysis
The Tools of Subsurface The Tools of Subsurface AnalysisAnalysis
Well logsWell logs Cores Cores SeismicSeismic Gravity & Gravity &
magneticsmagnetics
Facies analysis of subsurface Facies analysis of subsurface data depends on tools which data depends on tools which delimit of surfaces and provide delimit of surfaces and provide clues as to the sediments they clues as to the sediments they contain:contain:
GEOL 553 Lecture 3; Subsurface Analysis
Well Logs Versus SeismicWell Logs Versus SeismicWell Logs Versus SeismicWell Logs Versus Seismic Well logs Well logs
Great vertical resolution Great vertical resolution Delimit bounding surfacesDelimit bounding surfacesEstablish lithology of sediments Establish lithology of sediments
penetratedpenetrated SeismicSeismic
Great lateral continuity and Great lateral continuity and resolutionresolution
Define gross sediment geometryDefine gross sediment geometry
GEOL 553 Lecture 3; Subsurface Analysis
Tools are Keys to Allostratigraphy &
Sequence Stratigraphy
Tools are Keys to Allostratigraphy &
Sequence Stratigraphy AllostratigraphyAllostratigraphy: bounding discontinuities : bounding discontinuities
including erosion surfaces, marine including erosion surfaces, marine flooding surfaces, tuffs, tempestite, flooding surfaces, tuffs, tempestite, and/or turbidite boundaries etc. as time and/or turbidite boundaries etc. as time markersmarkers
Sequence StratigraphySequence Stratigraphy: higher level : higher level allostratigraphic model which interprets allostratigraphic model which interprets depositional origin of sedimentary strata depositional origin of sedimentary strata as products of "relative sea level changeas products of "relative sea level change""
GEOL 553 Lecture 3; Subsurface Analysis
The Tools of Subsurface Analysis
The Tools of Subsurface Analysis
Well logsWell logs SeismicSeismic
Facies analysis of subsurface Facies analysis of subsurface data depends on tools which data depends on tools which delimit of surfaces and provide delimit of surfaces and provide clues as to the sediments they clues as to the sediments they contain:contain:
GEOL 553 Lecture 3; Subsurface Analysis
Well LogsWell Logs
Resistivity LogsResistivity Logs Spontaneous Potential (SP) LogsSpontaneous Potential (SP) Logs Gamma Ray LogsGamma Ray Logs Neutron LogsNeutron Logs Density LogsDensity Logs Sonic (acoustic) LogsSonic (acoustic) Logs
Delimit of surfaces & identify sediments Delimit of surfaces & identify sediments penetratedpenetrated
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Resistivity LogsResistivity Logs
Measures resistance of flow of Measures resistance of flow of electric currentelectric current
Is function of porosity & pore fluid Is function of porosity & pore fluid in rockin rock
Frequently used to identify Frequently used to identify lithologylithology
The most commonly used The most commonly used logs:logs:
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Spontaneous Potential (SP) Logs
Spontaneous Potential (SP) Logs
Measures electrical current in wellMeasures electrical current in well Result of salinity differences Result of salinity differences
between formation water and the between formation water and the borehole mudborehole mud
Separates bed boundaries of Separates bed boundaries of permeable sands & impermeable permeable sands & impermeable shales.shales.
Next most common Next most common loglog
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Gamma Ray LogsGamma Ray Logs
Records radioactivity of a formationRecords radioactivity of a formation Shales have high gamma radioactive Shales have high gamma radioactive
responseresponse Gamma ray logs infer grain size (and Gamma ray logs infer grain size (and
so subsequently inferred depositional so subsequently inferred depositional energy)energy)
Gamma ray logs are most commonly Gamma ray logs are most commonly used logs for sequence stratigraphic used logs for sequence stratigraphic analysisanalysis
Another common logAnother common log
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface AnalysisAfter Harris & Saller 1999
GEOL 553 Lecture 3; Subsurface Analysis
Neutron LogsNeutron Logs
Measures porosity of formationMeasures porosity of formation Uses quantity of hydrogen presentUses quantity of hydrogen present Measures lithology when used with Measures lithology when used with
Density LogDensity Log
Another common Another common loglog
GEOL 553 Lecture 3; Subsurface Analysis
Density LogsDensity Logs
Measures formation’s bulk densityMeasures formation’s bulk density Used as a porosity measureUsed as a porosity measure Differentiates lithologies with Differentiates lithologies with
Neutron LogNeutron Log Used with Sonic Logs to generate Used with Sonic Logs to generate
synthetic seismic traces to match synthetic seismic traces to match to seismic linesto seismic lines
A common logA common log
GEOL 553 Lecture 3; Subsurface Analysis
Sonic (Acoustic) LogsSonic (Acoustic) Logs
Measures of speed of sound in Measures of speed of sound in formationformation
Tied to porosity and lithologyTied to porosity and lithology Used with Density Logs to Used with Density Logs to
generate Synthetic Seismic traces generate Synthetic Seismic traces to match to Seismic linesto match to Seismic lines
Another common logAnother common log
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
The Tools of Subsurface Analysis
The Tools of Subsurface Analysis
Well logsWell logs SeismicSeismic
Facies analysis of subsurface Facies analysis of subsurface data depends on tools which data depends on tools which delimit of surfaces and provide delimit of surfaces and provide clues as to the sediments they clues as to the sediments they contain:contain:
GEOL 553 Lecture 3; Subsurface Analysis
SeismicSeismic
Define geometries of genetic Define geometries of genetic reflection packages that envelope reflection packages that envelope seismic sequences and systems seismic sequences and systems tractstracts
Identify bounding discontinuities Identify bounding discontinuities on basis of reflection termination on basis of reflection termination patterns and continuitypatterns and continuity
Seismic stratigraphic Seismic stratigraphic interpretation used to:interpretation used to:
GEOL 553 Lecture 3; Subsurface Analysis
Seismic BoundariesSeismic Boundaries
Toplap termination Toplap termination Truncation of sediment surface Truncation of sediment surface Often channel bottomOften channel bottom
Termination below discontinuity, Termination below discontinuity, or upper sequence boundaryor upper sequence boundary ::
Onlap over surfaceOnlap over surface Downlap surfaceDownlap surface
Above a discontinuity defining Above a discontinuity defining lower sequence boundary:lower sequence boundary:
GEOL 553 Lecture 3; Subsurface Analysis
Seismic BoundariesSeismic Boundaries
Below Boundary - Toplap terminationBelow Boundary - Toplap termination
GEOL 553 Lecture 3; Subsurface Analysis
Seismic BoundariesSeismic Boundaries
Below Boundary -Below Boundary - Truncation of Truncation of surfacesurface
GEOL 553 Lecture 3; Subsurface Analysis
Seismic BoundariesSeismic Boundaries
ChanneledChanneled
Surface Surface
– – Below Below BoundaryBoundary
GEOL 553 Lecture 3; Subsurface Analysis
Seismic BoundariesSeismic BoundariesOver Boundary - Onlap onto surfaceOver Boundary - Onlap onto surface
GEOL 553 Lecture 3; Subsurface Analysis
Seismic BoundariesSeismic BoundariesOver Boundary- Downlap onto Over Boundary- Downlap onto
surfacesurface
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Sequence StratigraphySequence Stratigraphy
Surfaces of erosion & non-deposition Surfaces of erosion & non-deposition (sequence boundaries)(sequence boundaries)
Flooding (trangressive surfaces [TS] &/or Flooding (trangressive surfaces [TS] &/or maximum flooding surfaces [mfs]) & high maximum flooding surfaces [mfs]) & high stand condensed surfacesstand condensed surfaces
Subdivision & interpretation of Subdivision & interpretation of sedimentary record using a framework sedimentary record using a framework surfaces seen in outcrops, surfaces seen in outcrops, well logs, & 2-well logs, & 2-D and 3-D seismicD and 3-D seismic. . Include:Include:
This framework used to predict the This framework used to predict the extent of sedimentary facies extent of sedimentary facies geometry, lithologic character, geometry, lithologic character, grain size, sorting & reservoir grain size, sorting & reservoir qualityquality
GEOL 553 Lecture 3; Subsurface Analysis
Tools Define Bounding Surfaces Tools Define Bounding Surfaces
Relative time framework for sedimentary Relative time framework for sedimentary successionsuccession
Better understanding of inter-Better understanding of inter-relationship of depositional settings & relationship of depositional settings & their lateral correlationtheir lateral correlation
These surfaces subdivide These surfaces subdivide sedimentary rocksedimentary rock &provide:-provide:-
Conceptual models follow that link the processes that formed the sediments and enable the prediction of their gross geometries
GEOL 553 Lecture 3; Subsurface Analysis
Sequence geometries are subdivided and Sequence geometries are subdivided and defined bydefined by
Maximum Flooding Surfaces (mfs) Maximum Flooding Surfaces (mfs) Transgressive Surfaces (TS) Transgressive Surfaces (TS) Sequence Boundaries (SB)Sequence Boundaries (SB)
Define how vertical succession or stacking Define how vertical succession or stacking patterns of unconfined sheets are arranged patterns of unconfined sheets are arranged
Prograde (step seaward) Prograde (step seaward) Retrograde (step landward) Retrograde (step landward) Aggrade (build vertically)Aggrade (build vertically)
Sheets and unconfined lobes may containSheets and unconfined lobes may containNon-amalgamated bodiesNon-amalgamated bodies
Amalgamated, multi-storied bodiesAmalgamated, multi-storied bodiesIncised topographic fill of valleysIncised topographic fill of valleysUnconfined but localized lobes from point & Unconfined but localized lobes from point & multiple up dip sourcesmultiple up dip sourcesUnconfined but localized build ups (carbonates)Unconfined but localized build ups (carbonates)
Hierarchy of GeometriesHierarchy of Geometries
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Sequence geometries are subdivided and Sequence geometries are subdivided and defined bydefined by
Maximum Flooding Surfaces (mfs) Maximum Flooding Surfaces (mfs) Transgressive Surfaces (TS) Transgressive Surfaces (TS) Sequence Boundaries (SB)Sequence Boundaries (SB)
Define how vertical succession or stacking Define how vertical succession or stacking patterns of unconfined sheets are arranged patterns of unconfined sheets are arranged
Prograde (step seaward) Prograde (step seaward) Retrograde (step landward) Retrograde (step landward) Aggrade (build vertically)Aggrade (build vertically)
Sheets and unconfined lobes may containSheets and unconfined lobes may containNon-amalgamated bodiesNon-amalgamated bodies
Amalgamated, multi-storied bodiesAmalgamated, multi-storied bodiesIncised topographic fill of valleysIncised topographic fill of valleysUnconfined but localized lobes from point & Unconfined but localized lobes from point & multiple up dip sourcesmultiple up dip sourcesUnconfined but localized build ups (carbonates)Unconfined but localized build ups (carbonates)
Hierarchy of GeometriesHierarchy of Geometries
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Sequence geometries are subdivided and Sequence geometries are subdivided and defined bydefined by
Maximum Flooding Surfaces (mfs) Maximum Flooding Surfaces (mfs) Transgressive Surfaces (TS) Transgressive Surfaces (TS) Sequence Boundaries (SB)Sequence Boundaries (SB)
Define how vertical succession or stacking Define how vertical succession or stacking patterns of unconfined sheets are arranged patterns of unconfined sheets are arranged
Prograde (step seaward) Prograde (step seaward) Retrograde (step landward) Retrograde (step landward) Aggrade (build vertically)Aggrade (build vertically)
Sheets and unconfined lobes may containSheets and unconfined lobes may containNon-amalgamated bodiesNon-amalgamated bodies
Amalgamated, multi-storied bodiesAmalgamated, multi-storied bodiesIncised topographic fill of valleysIncised topographic fill of valleysUnconfined but localized lobes from point & Unconfined but localized lobes from point & multiple up dip sourcesmultiple up dip sourcesUnconfined but localized build ups (carbonates)Unconfined but localized build ups (carbonates)
Hierarchy of GeometriesHierarchy of Geometries
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Sequence geometries are subdivided and Sequence geometries are subdivided and defined bydefined by
Maximum Flooding Surfaces (mfs) Maximum Flooding Surfaces (mfs) Transgressive Surfaces (TS) Transgressive Surfaces (TS) Sequence Boundaries (SB)Sequence Boundaries (SB)
Define how vertical succession or stacking Define how vertical succession or stacking patterns of unconfined sheets are arranged patterns of unconfined sheets are arranged
Prograde (step seaward) Prograde (step seaward) Retrograde (step landward) Retrograde (step landward) Aggrade (build vertically)Aggrade (build vertically)
Sheets and unconfined lobes may containSheets and unconfined lobes may containNon-amalgamated bodiesNon-amalgamated bodies
Amalgamated, multi-storied bodiesAmalgamated, multi-storied bodiesIncised topographic fill of valleysIncised topographic fill of valleysUnconfined but localized lobes from point & Unconfined but localized lobes from point & multiple up dip sourcesmultiple up dip sourcesUnconfined but localized build ups (carbonates)Unconfined but localized build ups (carbonates)
Hierarchy of GeometriesHierarchy of Geometries
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Sequence geometries are subdivided and Sequence geometries are subdivided and defined bydefined by
Maximum Flooding Surfaces (mfs) Maximum Flooding Surfaces (mfs) Transgressive Surfaces (TS) Transgressive Surfaces (TS) Sequence Boundaries (SB)Sequence Boundaries (SB)
Define how vertical succession or stacking Define how vertical succession or stacking patterns of unconfined sheets are arranged patterns of unconfined sheets are arranged
Prograde (step seaward) Prograde (step seaward) Retrograde (step landward) Retrograde (step landward) Aggrade (build vertically)Aggrade (build vertically)
Sheets and unconfined lobes may containSheets and unconfined lobes may containNon-amalgamated bodiesNon-amalgamated bodies
Amalgamated, multi-storied bodiesAmalgamated, multi-storied bodiesIncised topographic fill of valleysIncised topographic fill of valleysUnconfined but localized lobes from point & Unconfined but localized lobes from point & multiple up dip sourcesmultiple up dip sourcesUnconfined but localized build ups (carbonates)Unconfined but localized build ups (carbonates)
Hierarchy of GeometriesHierarchy of Geometries
GEOL 553 Lecture 3; Subsurface Analysis
Ebb Ooid Delta - UAEEbb Ooid Delta - UAE
GEOL 553 Lecture 3; Subsurface Analysis
Delta Mouth Bar - Kentucky
Delta Mouth Bar - Kentucky
Note Incised SurfaceNote Incised Surface
GEOL 553 Lecture 3; Subsurface Analysis
Channel – Gulf CoastChannel – Gulf Coast
Note Incised SurfaceNote Incised Surface
GEOL 553 Lecture 3; Subsurface Analysis
Flood Deltas & Channels - Kty
Flood Deltas & Channels - Kty
GEOL 553 Lecture 3; Subsurface Analysis
TidalChannel
sKhor
alBazam
-UAE
TidalChannel
sKhor
alBazam
-UAE
GEOL 553 Lecture 3; Subsurface Analysis
Tidal, Storm or Tsunami Channel
Tidal, Storm or Tsunami Channel
Note Incised SurfaceNote Incised Surface
GEOL 553 Lecture 3; Subsurface Analysis
Tsunami Load & Drape - Kty
Tsunami Load & Drape - Kty
Note Uniform Thickness of LayerNote Uniform Thickness of Layer
GEOL 553 Lecture 3; Subsurface Analysis
Clastic Sequence Stratigraphic Hierarchies
Clastic Sequence Stratigraphic Hierarchies
GEOL 553 Lecture 3; Subsurface Analysis
Channels & Shelves Channels & Shelves
Chann
el
Chann
elShelfShelf
Both have unique Both have unique processes & structures that processes & structures that
can be used to identify can be used to identify their settingtheir setting
GEOL 553 Lecture 3; Subsurface Analysis
Tools Enable Sequence Stratigraphic Analysis
Tools Enable Sequence Stratigraphic Analysis
Subdivision of section into sequences, Subdivision of section into sequences, parasequences and beds.parasequences and beds.
Link conceptual models with mix of Link conceptual models with mix of components of the individual sequence, components of the individual sequence, parasequence or beds parasequence or beds
Use these to explain the depositional Use these to explain the depositional setting in terms of their lithology, grain setting in terms of their lithology, grain size, sedimentary structures, contacts size, sedimentary structures, contacts character (gradational, abrupt) etccharacter (gradational, abrupt) etc
This analysis involvesThis analysis involves
GEOL 553 Lecture 3; Subsurface Analysis
SequenceStratigraphi
cAnalysis
SequenceStratigraphi
cAnalysis
End of the LectureEnd of the Lecture
Can it be supper Can it be supper time?time?
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
GEOL 553 Lecture 3; Subsurface Analysis
Unconfined Flow - Not in a ChannelUnconfined Flow - Not in a Channel Unique ProcessesUnique Processes
Flow is in all directions Flow is in all directions No lateral boundaries, only upper and lower No lateral boundaries, only upper and lower boundaries boundaries Velocity changes: high to low Velocity changes: high to low
Sediment responsesSediment responsesDecrease in grain size: Fining outward Decrease in grain size: Fining outward (coarse to fine)(coarse to fine)Erosional/sharp/gradational contacts Erosional/sharp/gradational contacts Accretion: Downstream, upstream and Accretion: Downstream, upstream and vertical vertical Decrease in sedimentary structures away Decrease in sedimentary structures away from source from source
GeometriesGeometriesSheets Sheets Thin in direction of flow Thin in direction of flow