Quantitative Seismic Interpretation: Applying Rock Physics Tools to Reduce Interpretation Risk

408 Pages·2005·19.5 MB·English

by  Avseth P.

Quantitative Seismic Interpretation
ApplyingRockPhysicsToolstoReduceInterpretationRisk
Seismicdataanalysisisoneofthekeytechnologiesforcharacterizingreservoirsand
monitoringsubsurfaceporefluids.Whiletherehavebeengreatadvancesin3Dseismic
dataprocessing,thequantitativeinterpretationoftheseismicdataforrockproperties
stillposesmanychallenges.
Quantitative Seismic Interpretation demonstrates how rock physics can be applied
to predict reservoir parameters, such as lithologies and pore fluids, from seismically
derived attributes. It shows how the multidisciplinary combination of rock physics
modelswithseismicdata,sedimentologicalinformation,andstochastictechniquescan
leadtomorepowerfulresultsthancanbeobtainedfromasingletechnique.Theauthors
provide an integrated methodology and practical tools for quantitative interpretation,
uncertainty assessment, and characterization of subsurface reservoirs using well-log
and seismic data. They illustrate the advantages of these new methodologies, while
providingadviceaboutlimitationsofthemethodsandtraditionalpitfalls.
Thisbookisaimedatgraduatestudents,academics,andindustryprofessionalswork-
ingintheareasofpetroleumgeoscienceandexplorationseismology.Itwillalsointerest
environmental geophysicists seeking a quantitative subsurface characterization from
shallow seismic data. The book includes case studies and problem sets. A website
(http://publishing.cambridge.org/resources/0521816017)offersMatlab codes,plus
seismicandwell-logdata,whichwillallowreaderstogainahands-onunderstanding
ofthemethodologies.
PerAvsethisaseniorgeophysicistattheNorskHydroresearchcenterinBergen,Norway.
PerreceivedhisM.Sc.inAppliedPetroleumGeosciencesfromtheNorwegianInstitute
ofTechnology,andhisPh.D.inGeophysicsfromStanfordUniversity,California.Per’s
research interests include applied rock physics, and AVO analysis, for quantitative
seismicexplorationandreservoircharacterization.Perhaswide-ranginginternational
experience in applying quantitative seismic interpretation methodologies, and has
taughtin-housecoursesforNorskHydro.
TapanMukerjiisaresearchassociatewiththeStanfordRockPhysicsProjectatStanford
University,wherehereceivedhisPh.D.inGeophysics.Hisresearchinterestsinclude
wavepropagationandstatisticalrockphysics,andhespecializesinappliedrockphysics
andgeostatisticalmethodsforseismicreservoircharacterization,fracturedetection,4D
monitoring,andshallowsubsurfaceenvironmentalapplications.Tapanhascombined
experienceinconductingleadingedgeappliedresearchwithteaching.Heisaco-author
of The Rock Physics Handbook (Cambridge, 1998) and has taught industry courses.
Tapan received the Karcher award from the Society of Exploration Geophysicists in
2000.
Gary Mavko co-directs the Stanford Rock Physics and Borehole Geophysics Project
(SRB),agroupofapproximately25researchersworkingonproblemsrelatedtowave
propagation in Earth materials – the field of rock physics. Gary received his Ph.D.
in Geophysics from Stanford in 1977. In 1984 he joined Entropic Geophysical in
its first months as a start-up reflection seismic processing company and eventually
became their VP of research and development. He is now Professor (Research) of
Geophysics at Stanford University. Gary co-authored The Rock Physics Handbook
(Cambridge,1998)andhasbeenaninvitedinstructorfornumerousindustrycourses.
Gary received the Honorary Membership award from the Society of Exploration
Geophysicistsin2001.
Quantitative
Seismic Interpretation
Applying Rock Physics Tools to Reduce Interpretation Risk
Per Avseth
NorskHydroResearchCentre,Bergen
Tapan Mukerji
StanfordUniversity
Gary Mavko
StanfordUniversity
cambridge university press
Cambridge,NewYork,Melbourne,Madrid,CapeTown,Singapore,Sa˜oPaulo, Delhi
CambridgeUniversityPress
TheEdinburghBuilding,CambridgeCB28RU,UK
Published in the United States of America by Cambridge University Press, New York
www.cambridge.org
Informationonthistitle:www.cambridge.org/9780521816014
(cid:1)C P.Avseth,T.MukerjiandG.Mavko2005
Thispublicationisincopyright.Subjecttostatutoryexception
andtotheprovisionsofrelevantcollectivelicensingagreements,
noreproductionofanypartmaytakeplacewithout
thewrittenpermissionofCambridgeUniversityPress.
Firstpublished2005
Sixth printing 2008
PrintedintheUnitedKingdomattheUniversityPress,Cambridge
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Butafterobservationandanalysis,whenyoufindthatanythingagreeswith
reasonandisconducivetothegoodandbenefitofoneandall,thenaccept
itandliveuptoit.TheBuddha

Contents
Preface page xi
1 Introduction to rock physics 1
1.1 Introduction 1
1.2 Velocity–porosityrelationsformappingporosityandfacies 2
1.3 Fluidsubstitutionanalysis 15
1.4 Pressureeffectsonvelocity 24
1.5 Thespecialroleofshear-waveinformation 30
1.6 Rockphysics“Whatifs?”:fluidandlithologysubstitution 42
1.7 Allmodelsarewrong...someareuseful 43
2 Rock physics interpretation of texture, lithology
and compaction 48
2.1 Introduction 48
2.2 Thelinkbetweenrockphysicspropertiesandsedimentarymicrostructure:
theoryandmodels 51
2.3 Example:rockphysicsinterpretationofmicrostructureinNorthSea
turbiditesystems 70
2.4 Relatingrockphysicstolithofaciesanddepositionalenvironments 81
2.5 Example:seismiclithofaciesinaNorthSeaturbiditesystem 83
2.6 Rockphysicsdepthtrends 90
2.7 Example:rockphysicsdepthtrendsandanomaliesinaNorthSeafield 96
2.8 Rockphysicstemplates:atoolforlithologyandfluidprediction 101
2.9 Discussion 107
2.10 Conclusions 109
vii
viii Contents
3 Statistical rock physics: Combining rock physics, information
theory, and statistics to reduce uncertainty 111
3.1 Introduction 111
3.2 Whyquantifyuncertainty? 112
3.3 Statisticalrockphysicsworkflow 123
3.4 Informationentropy:somesimpleexamples 132
3.5 MonteCarlosimulation 136
3.6 Statisticalclassificationandpatternrecognition 138
3.7 Discussionandsummary 165
4 Common techniques for quantitative seismic interpretation 168
4.1 Introduction 168
4.2 Qualitativeseismicamplitudeinterpretation 168
4.3 AVOanalysis 180
4.4 Impedanceinversion 230
4.5 Forwardseismicmodeling 252
4.6 Futuredirectionsinquantitativeseismicinterpretation 256
5 Case studies: Lithology and pore-fluid prediction from
seismic data 258
5.1 Case1:Seismicreservoirmappingfrom3DAVOinaNorthSea
turbiditesystem 258
5.2 Case2:Mappinglithofaciesandpore-fluidprobabilitiesinaNorthSea
reservoirusingseismicimpedanceinversionsandstatisticalrockphysics 278
5.3 Case3:Seismiclithologypredictionandreservoirdelineationusing
statisticalAVOintheGranefield,NorthSea 295
5.4 Case4:AVOdepthtrendsforlithologyandporefluidclassificationin
unconsolidateddeep-watersystems,offshoreWestAfrica 306
5.5 Case5:Seismicreservoirmappingusingrockphysicstemplates.Example
fromaNorthSeaturbiditesystem 312
ix Contents
6 Workflows and guidelines 317
6.1 AVOreconnaissance 318
6.2 Rockphysics“Whatifs”andAVOfeasibilitystudies 320
6.3 RPTanalysis 322
6.4 AVOclassificationconstrainedbyrockphysicsdepthtrends 323
6.5 Seismicreservoircharacterizationconstrainedbylithofaciesanalysis
andstatisticalrockphysics 325
6.6 Whyandwhenshouldwedoquantitativeseismicinterpretation? 328
7 Hands-on 332
7.1 Introduction 332
7.2 Problems 332
7.3 Project 336
References 340
Index 356
Thecolorplatesaresituatedbetweenpages176and177.