Downloaded from … · hydrocarbon-generation-induced microcrack development, in organic mudstones — are discussed in Chapter 7. Finally, Chapter 8, “Seismic Analysis in Uncon-ventional

Downloaded from https://pubs.geoscienceworld.org/books/chapter-pdf/3700023/frontmatter.pdfby gueston 23 May 2019

Seismic Petrophysics in Quantitative Interpretation

Investigations in Geophysics Series No. 18

Lev Vernik

Rebecca Latimer, managing editorTad Smith, volume editor

SM

00-Vernik_FM.indd 1 12-08-2016 20:04:40


ISBN 978-0-931830-46-4 (Series)ISBN 978-1-56080-324-9 (Volume)

Library of Congress Control Number: 2016945722

Copyright 2016Society of Exploration Geophysicists8801 S. Yale, Ste. 500Tulsa, OK U.S.A. 74137-3575

All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transcribed in any form or by any means, electronic or mechanical, including photocopying and recording, without prior written permission of the publisher.

Published 2016

Printed in the United States of America

00-Vernik_FM.indd 2 12-08-2016 20:04:40


About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi

Chapter 1: Petrophysics of Siliciclastic Rocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Petrophysical classification of siliciclastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Petrographic data and petrophysical classification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1Application to the core/log database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Petrophysical model building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Lithologic parameters Vcl and Vsh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8Total porosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Permeability prediction in siliciclastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13Seismic petrophysics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17Log editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Sonic log . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Density log . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Anisotropic correction of sonic logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Chapter 2: Pore Pressure and Stress State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Shale-compaction model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Porosity reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29Density model for stress computation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Vertical effective stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32Pore-pressure prediction from shale velocity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Sonic velocity versus effective stress in shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34Pore-pressure prediction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

The effective-stress tensor and the Shmin gradient . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Chapter 3: Seismic Rock Properties and Rock Physics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Theoretical models in rock physics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Fluid-saturation effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43Drained rock-frame moduli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45Cracks in dry and fluid-saturated rocks: The effect of aspect ratios . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46Drained rock-frame moduli: A mixture of cracks and pores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47Effects of pore/crack interactions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49Contact models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Contents

iii

00-Vernik_FM.indd 3 12-08-2016 20:04:40


Drained frame moduli and effective stress . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Rock-physics modeling in sand/shale sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Pore shapes and porosity thresholds in sands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56Consolidated sandstones . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58Unconsolidated and poorly consolidated sands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61Sandstone diagenesis models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64Conventional shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66Rock-physics templates in siliciclastic sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69

VP-VS and AI-SI relationships in siliciclastics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72The VP-VS relationship. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72The AI-SI relationship . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Fluid substitution and the AI-SI template . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 784D modeling of sands and sandstones. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Chapter 4: AVO Analysis: Rock-physics Basis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Linearized AVO equations and their features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87AVO classification in AI-SI space . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89From the AI-SI template to synthetic-gather models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

AVO Class III and the zero-gradient case . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91AVO Class IV . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93AVO Classes I and II . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

VTI anisotropy effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97The fluid factor in prospect risk mitigation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100Tuning effects in AVO synthetic modeling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Chapter 5: Simultaneous AI-SI Inversion and N/G Computation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Log editing and the AI-SI template . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105Anisotropy correction of sonic velocities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106Additional log editing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107AI-SI crossplot . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Modeling N/G . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109Seismic N/G computation from simultaneous inversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111

AI-SI inversion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111Sand volume computation and net/gross mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114

Effects of lithology and fluid on prestack attributes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118

Chapter 6: Seismic Petrophysics of Unconventional Reservoirs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

Petrologic data in unconventional shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121Rock composition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121Organic richness and thermal maturity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122Rock texture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Log model for unconventional shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129Microstructural observations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129Kerogen-fraction log . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131Total porosity and kerogen porosity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131Water saturation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133Model applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134

Rock physics of unconventional shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137Core measurements of velocity and anisotropy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137Phase velocity versus group velocity. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139Intrinsic velocity and anisotropy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141Effect of kerogen on velocities and anisotropy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 144

iv Seismic Petrophysics in Quantitative Interpretation

00-Vernik_FM.indd 4 12-08-2016 20:04:40


Stress dependence of velocity and anisotropy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153Modeling stress dependence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 155Rock-physics model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 158VP-VS and AI-SI relationships . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

Chapter 7: Geomechanics of Organic Shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167

Elastic-property relationships in TI shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167Can brittleness be estimated from elastic properties? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168Static and dynamic elastic parameters in anisotropic mudrocks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169Elasticity-based brittleness of organic mudrocks: A controversial notion . . . . . . . . . . . . . . . . . . . . . . . . . . . 171Shmin stress-gradient estimation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173

Uniaxial-strain-based approach. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 173Anisotropy prediction in organic and conventional shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174Stress profiling from log data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175

Geomechanics of maturation-induced microcracking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 176

Chapter 8: Seismic Analysis in Unconventional Shales . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183

Reservoir-scale anisotropy estimation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183Seismic ties. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184TOC estimation from an AI-SI template . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186AI-SI Inversion of Prestack Seismic Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191TOC mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191Shmin stress-gradient mapping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

Contents v

00-Vernik_FM.indd 5 12-08-2016 20:04:40


This page has been intentionally left blank


Lev Vernik is a geophysics consultant and owner of Seismic Petrophysics, LLC, in Houston, Texas, USA, and a research profes-sor of geophysics at the University of Houston. He has previously held various geoscience positions with Arco, Vastar Resources, BP, Noble Energy, and Marathon Oil, focusing on seismic petrophysics, AVO modeling/analysis, prestack seismic inversion, and geome-chanics. Lev’s long career in subsurface characterization started in the former Soviet Union, where he was involved in drilling and in-vestigating the world’s deepest well on Kola Peninsula. His research continued at the Stanford Rock Physics Project and then in the tech-nology groups of the aforementioned five oil and gas companies.

About the Author

vii

00-Vernik_FM.indd 7 12-08-2016 20:04:40


This page has been intentionally left blank


Recent advances in seismic acquisition and process-ing technologies have led to enormous progress in oil and gas exploration and reservoir characterization. Quanti-tative seismic interpretation also could have improved significantly if we had had the internally consistent meth-odologies and workflows necessary for seismic modeling. Seismic petrophysics plays the key role in this respect.

Because the methodologies of petrophysical analysis lead to uncertainties in estimating key parameters, such as rock composition, texture, porosity, permeability, and saturation, it is important to (1) understand the rock for-mations for their proper characterization and (2) incorpo-rate proper rock-physics and geomechanics concepts in predicting the seismic signatures of those formations.

Over the last several years, our understanding of seismic rock properties and our ability to model those properties — VP, VS, and density — has improved substan-tially. Nonetheless, a certain amount of confusion remains with respect to the petroelastic classification of rocks, the terminology used, the selection of models, the parameter-ization, and the identification of the primary controls on the distribution of rock properties in the subsurface. These issues are discussed in Chapters 1 and 3 of this book.

Pore-pressure prediction from well-log and seismic data is critical in drilling operations and also is important in estimations of geomechanical parameters and stress-states from seismic data. It is well established that stresses in the subsurface have a direct impact on rock physics and, hence, on seismic amplitudes. Indeed, knowledge of effective-stress variations laterally and with depth mark-edly reduces interpretation uncertainty and helps separate intrinsic effects from extrinsic influences of pore pressure and stress state on seismic rock properties. An approach to pore-pressure and vertical-effective-stress analyses is discussed in Chapter 2.

The essence of seismic-related rock physics consists of finding relationships between seismic rock properties and their petrographic and petrophysical parameters, in-cluding their mineralogy, texture, diagenesis, reservoir properties, and effective stress. These problems are

discussed in Chapter 3, “Seismic Rock Properties and Rock Physics.” The chapter also addresses certain contro-versial issues, such as parameterization and appropriate model selection. The outcomes of this discussion are sev-eral rock-physics templates that feature the key petrophys-ical groups of siliciclastics in velocity-versus-porosity space and acoustic-impedance-versus-shear-impedance (AI-SI) space. Those templates naturally incorporate the effect of rock compaction and diagenesis and therefore are essential in modern seismic inversion interpretation.

Chapter 4, “AVO Analysis: Rock-physics Basis,” is the core of the book. This chapter integrates seismic pet-rophysics with seismic amplitude analysis — notably, with amplitude variation with offset (AVO) or angle of incidence (AVA). The AVO classification scheme and in-terpretation methodology offered here differ from the classic scheme of intercept/gradient analysis and invoke acoustic- and shear-impedance templates instead of inter-cept/gradient crossplots. That allows a user to streamline AVO behavior predictions during seismic petrophysics analysis of the log data early in the workflow. It also pro-vides a robust quality assurance during synthetic forward modeling. In turn, that modeling can be used in seismic processing and gather conditioning for prestack attribute computation and simultaneous impedance inversion of seismic data.

The AI-SI templates and their benefits in prestack in-version of sand/shale sequences are exemplified in Chapter 5. Marked mismatches in frequency content be-tween seismic data and log data result in large differences in vertical resolution and lead to the argument that limita-tions exist in our ability to directly invert for certain res-ervoir properties (e.g., porosity and permeability) in high-ly heterogeneous sand and sandstone reservoirs. However, another valuable reservoir parameter — the net-to-gross thickness ratio — lends itself to fairly accurate estima-tions from seismic inversion in many cases.

Over the last several years, both the exploration and the development of unconventional shales have grown dramatically and, in fact, many operators have switched to

Preface

ix

00-Vernik_FM.indd 9 12-08-2016 20:04:40


unconventional plays. It is often thought that these plays also require unconventional approaches to reservoir charac-terization. In Chapter 6, “Seismic Petrophysics of Unconventional Reservoirs,” it is demonstrated that the fun-damental workflows typical for conventional reservoirs still are applicable in organic shales. However, the complexity of rock-physics modeling increases in proportion to the ad-ditional parameters of interest, such as total organic carbon (TOC) content and thermal maturity, and their effects on organic porosity, overpressure, and the stress sensitivity of seismic velocities. Important geomechanical issues related to predicting horizontal-well- completion quality — issues such as brittleness, least-horizontal-stress gradient, and hydrocarbon- generation-induced microcrack development, in organic mudstones — are discussed in Chapter 7.

Finally, Chapter 8, “Seismic Analysis in Uncon-ventional Shales,” presents examples of seismic forward modeling and prestack inversion for some of the most le-veraging parameters of unconventional shale reservoirs — both the intrinsic parameters (e.g., TOC content) and the extrinsic ones (e.g., horizontal stress gradient). It ap-pears that AI-SI templates modified for organic shales can be adapted for those evaluations, and the organic richness and fracability of organic mudrocks can be mapped on the basis of simultaneous seismic inversion results.

This book is, of course, complementary to other pub-lications on related topics, such as Acoustics of Porous Media (Bourbie et al., 1987), AVO (Chopra and Castagna, 2014), Introduction to the Physics of Rocks (Gueguén and

Palciauskas, 1994), Seismic Data Analysis (Yilmaz, 2001), Quantitative Seismic Interpretation (Avseth et al., 2005), and The Rock Physics Handbook (Mavko et al., 2009). Many theoretical models presented here originated from the work of Mark Kachanov (Tufts University) with various coauthors.

Methodology and workflows described in this book have been successfully applied in many exploration and reservoir characterization projects worldwide and result-ed in significant oil and gas discoveries and accurate re-serve calculations, particularly in the Gulf of Mexico, West Africa, North Sea, Norwegian Sea, and Eastern Mediterranean provinces.

Seismic Petrophysics in Quantitative Interpretation is written for oil and gas industry professionals and academi-cians who are concerned with the use of seismic data in petroleum exploration and production. In addition, it should prove useful toward thoughtful applications of those data by geotechnical engineers. Seismic interpretation can be made simple and robust by integrating rock-physics principles with the seismic and petrophysical attributes that bear on the properties of conventional reservoirs (thick-ness, net/gross, lithology, porosity, permeability, and satu-ration) and of unconventional reservoirs (thickness, lithol-ogy, organic richness, and thermal maturity). Practical so-lutions can be used to address existing interpre-tation problems in rock-physics-based AVO analysis and prestack seismic inversion in order to streamline the workflows in subsurface characterization.

x Seismic Petrophysics in Quantitative Interpretation

00-Vernik_FM.indd 10 12-08-2016 20:04:40


I wish to thank Marathon Oil Corporation for permis-sion to publish this book. Special thanks are extended to David Brimberry, Dicman Alfred, Jim Allen, Robert Blanchard, Vladimir Grechka, Glory Kamath, Yulia Khadeeva, Scott Koza, Jadranka Milovac, and Chris Tuttle (all presently or formerly with Marathon Oil), Mark Boggards and Niven Shumaker (Noble Energy), and Tim Lane and Leon Thomsen (ex-BP). Cooperation with Mark Kachanov (Tufts University) over the last five years has been very useful in bringing me fresh perspec-tives on theoretical elasticity, whereas discussions with Brian Russell, Tad Smith, Kitty Milliken, and Öz Yilmaz

have helped to focus on what is important. Special thanks go to Amos Nur (Stanford University) for the jumpstart he provided me in my early years in the United States. I am also enormously grateful to Rebecca Latimer, Tad Smith, Konstantin Azbel, and Marco Perez for their thoughtful reviews and many helpful suggestions.

Special thanks also go to the SEG publication group, led by Susan Stamm, for their diligence in the book’s early review and later composition and printing phases. Anne Thomas’s help with style editing and making the book consistent with the SEG standards is most appreciated.

Acknowledgments

xi

00-Vernik_FM.indd 11 12-08-2016 20:04:40


Documents

Downloaded from … · hydrocarbon-generation-induced microcrack development, in organic mudstones — are discussed in Chapter 7. Finally, Chapter 8, “Seismic Analysis in Uncon-ventional