石油岩石学Petrophysics.pdf

second edition Theory and Practice of Measuring Reservoir Rock and Fluid Transport Properties 1 Petrophysics second edition and Practice of Measuring Reservoir Rock and Fluid Transport Properties 3rm* Djebbar Tiab and Erle C. Donaldson ELSEVIER AMSTERDAM - BOSTON * HEIDELBERG LONDON * NEWYORK * OXFORD - PARIS SAN DIEGO * SAN FRANCISCO * SINGAPORE SYDNEY - TOKYO G p Gulf Professional Gulfhfessional publishing is an imprint of usevier P W Publishing Gulf Professional Publishing is an imprint of Elsevier 200 Wheeler Road, Burlington, MA 01803, USA Linacre House, Jordan Hill, Oxford OX2 8DP, UK Copyright 0 2004, Elsevier, Inc. All rights reserved. No part of this publication may be reproduced, stored in a retri system, or transmitted in any or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior written permission of the publisher. Permissions may be sought directly from Elsevier’s Science when the laboratory was transferred to the U.S. Department of Energy, Dr. Donaldson continued as chief of petroleum reservoir characterization. When the laboratory shifted to private industry for operations, he joined the faculty of the School of Petroleum and Geological Engineering at the University of Oklahoma as associate professor. Since retiring from the university in 1990, he has consulted for various oil companies, universities, and U.S. agencies including the Environmental Protection Agency, the U.S. Navy Ordinance Center, King Fahd Research Institute of Saudi Arabia, and companies in the U.S., Brazil, Venezuela, Bolivia, and Thailand. Dr. Donaldson has earned four degrees a Ph.D. in chemical engineering from the University of Tulsa, an M.S. in organic chemistry from the University of South Carolina, a B.Sc. in chemical engineering from the University of Houston, and a B.Sc. in chemistry from The Citadel. He has served as chairman of committees and sessions for the Society of Petroleum Engineers and the American Chemical Society, as well as other national and international conferences. He is a member of the SPE Twenty-Five Year Club, and is currently the managing editor of the Journal of Petroleum Science and Engineering. X i X ACKNOWLEDGMENT The authors are especially indebted to Academician George V. Chilingar, Professor of Civil and Petroleum Engineering at the University of Southern California, Los Angeles, who acted as the technical, scientific, and consulting editor. We can never thank him enough for his prompt and systematic editing of this book. He is forever our friend. PREFACE TO THE FIRST EDITION This book presents the developed concepts, theories, and laboratory procedures as related to the porous rock properties and their interactions with fluids gases, hydrocarbon liquids, and aqueous solutions. The properties of porous subsurface rocks and the fluids they contain govern the rates of fluid flow and the amounts of residual fluids that remain in the rocks after all economical means of hydrocarbon production have been exhausted. It is estimated that the residual hydrocarbons locked in place after primary and secondary production, on a worldwide scale, is about 40 of the original volume in place. This is a huge hydrocarbon resource target for refined reservoir characterization using the theories and procedures of petrophysics to enhance the secondary recovery or implement tertiary EOR recovery. The use of modern s for reservoir characterization with a combination of petrophysics and mathematical modeling is bringing new life into many old reservoirs that are near the point of abandonment. This book brings together the theories and procedures from the scattered sources in the literature. In order to establish the basis for the study of rock properties and rock-fluid interactions, the first two chapters are devoted to a review of mineralogy, petrology, and geology. Next, the two rock properties that are perhaps the most important for petroleum engineering, i.e., porosity and permeability, are presented in detail in Chapter 3. Finally, the problem of porosity-permeability correlation has been solved. The subjects of Chapter 4 are the electrical resistivity and water saturation of rocks which are the basis for well logging techniques. The next chapter takes up the theories and applications of capillary pressure and wettability to various phenomena associated with fluid-saturated rocks, such as residual saturations due to fluid trapping, variations of relative permeabilities, effects on production, and the measurements and use of capillary pressure for determination of pore size distributions and wettability. Chapter 6 is devoted exclusively to the applications of Darcy’s Law to linear, radial, laminar, and turbulent flows, and multiple variations of permeability and porosity in rocks. Chapter 7 presents an introduction to the important topic of rock mechanics by considering rock deation, compressibility, and the effects of stress on porosity and permeability. The book ends with a discussion of rock-fluid interactions associated with various types of ation damage. Finally, a set of 19 laboratory procedures for determination of the rock and fluid properties, xxi and rock-fluid interactions-which are presented in the eight chapters of the book-are included in an Appendix. In addition to detailed experimental procedures, the authors have included examples for each experiment. Although this book was primarily organized and prepared for use as a textbook and laboratory manual, it also will serve as a reference book for petroleum engineers and geologists, and can be used in petrophysical testing laboratories. It is the first comprehensive book published on the subject since 1960 J. W. Amyx, D. M. Bass, Jr., and R. L. Whiting, Petroleum Reservoir Engineering, McGraw-Hill, New York, NY. The book also can serve as the basis for the advancement of theories and applications of petrophysics as the technology of petroleum engineering continues to improve and evolve. This unique book belongs on the bookshelf of every petroleum engineer and petroleum geologist. Djebbar Tiab Erle C. Donaldson George I Chilingar xxii PREFACE TO THE SECOND EDITION This second edition of Petrophysics has been designed to amplify the first volume from 8 to 10 chapters and comply with suggestions from colleagues and numerous readers who were generous in taking time to convey their advice. Readers will find that the first chapter, an introduction to mineralogy, has been considerably amplified to assist in better recognition of the multitude of minerals and rocks. There was no noticeable change to Chapter 2 Introduction to Petroleum Geology, Chapter 7 Applications of Darcy’s Law, or Chapter 10 Fluid-Rock Interactions. Chapter 3 Porosity and Permeability underwent major changes. The following topics were added concept of flow units, directional permeability, correlations between horizontal and vertical permeability, averaging techniques, Dykstra-Parsons coefficient of permeability variation, effective permeability from cores and well test data, and several more examples. Chapter 4 ation Resistivity and Water Saturation was amplified, mainly to include the characterization and identification of flow units in shaly ations, and more examples. Chapter 5 of the first edition was divided into two new chapters Chapter 5 Capillary Pressure and Chapter 6 Wettability, because of the large amount of work that has been conducted on wettability since the publication of the first edition. Capillary pressure and wettability are, however, bound together because much of the basis for various tests and theories of wettability and its impact on oil recovery is based on capillary pressure behavior as a function of fluid saturation. It seems natural, therefore, that a thorough understanding of capillary pressure is necessary for the study of wettability. Chapter 8 Naturally Fractured Reservoirs is a new chapter. Practically all readers who contacted us suggested that we include a more detailed discussion of the petrophysical aspects of naturally fractured rocks. The main topics covered in this chapter are geological and engineering classifications of natural fractures, indicators of natural fractures, determination of fracture porosity and permeability, fracture intensity index, porosity partitioning coefficient, and effect of fracture shape on permeability. A new concept of hydraulic radius of fracture is introduced in this chapter. s for determining the fracture storage capacity and inter-porosity from well test data are briefly discussed. Several important topics were added to Chapter 9 Effect of Stress on Reservoir Rock Properties the effect of change in the stress field due to x x i i i depletion and repressurization, stress and critical borehole pressure in vertical and horizontal wells, critical pore pressure, and estimation of unconfined compressive rock strength from porosity data. The Appendix, covering petrophysics laboratory experiments, is essentially the same because the basic s for the experimental study of petrophysics have not changed very much. A recently developed general for calculation of relative permeability, however, was included in Experiment 12. The procedure is applicable to both constant rate and constant pressure unsteady state displacement. Djebbar Tiab Erle C. Donaldson xxiv UNITS Units of Area acre 43,540 ft2 4046.9 m2 ft2 0.0929 m2 hectare 10,000 m2 Constants Darcy 0.9869 mm2 Gas constant 82.05 atm x cm3/g mol x K 10.732 psi x ft3/lb mol x OR 0.729 atm x ft3/lb mol x OR Mol. wt. of air 28.97 Units of Length Angstrom 1 x IO- cm cm 0.3937 in. ft 30.481 cm in. 2.540 cm km 0.6214 mile m 39.370 in. 3.2808 ft Units of Pressure atm 760 mm Hg OOC 29.921 in. Hg 14.696 psi atm 33.899 ft water at 4C bar 14.5033 psi 0.987 atm 0.1 MPa dyne/cm2 6.895 kPa kilopascal ft water 0.4912 psi kgforce/cm2 14.223 psi psi 2.036 in. Hg OOC 6.895 kPa xxu Units of Temperature Degrees Fahrenheit OF 123C 32 Degrees Rankine OR 459.7 O F Degrees Kelvin K 273.16 “C Units of Volume acre-ft 43,560 ft3 7,758.4 bbl 1.2335 x lo3 m3 bbl 42 US gal 5.6145 ft3 0.1590 m3 cu ft ft3 7.4805 gal 0.1781 bbl 0.028317 m3 cu in. in3 16.387 cm3 cu m m3 6.2898 bbl gal 231 in3 3785.43 cm3 1,000 grams of solvent of solvent mass of solute equal to the molecular weight divided by the valence per 1,000 g of solvent molarity mass of solute equal to the molecular weight per normality equivalent weight of solute per 1,000 grams C H A P T E R 1 INTRODUCTION TO M I N ERALOGY Petrophysics is the study of rock properties and their interactions with fluids gases, liquid hydrocarbons, and aqueous solutions. The geologic material ing a reservoir for the accumulation of hydrocarbons in the subsurface must contain a three-dimensional network of interconnected pores in order to store the fluids and allow for their movement within the reservoir. Thus the porosity of the reservoir rocks and their permeability are the most fundamental physical properties with respect to the storage and transmission of fluids. Accurate knowledge of these two properties for any hydrocarbon reservoir, together with the fluid properties, is required for efficient development, management, and prediction of future perance of the oilfield. The purpose of this text is to provide a basic understanding of the physical properties of porous geologic materials, and the interactions of various fluids with the interstitial surfaces and the distribution of pores of various sizes within the porous medium. Procedures for the measurement of petrophysical properties are included as a necessary part of this text. Applications of the fundamental properties to subsurface geologic strata must be made by analyses of the variations of petrophysical properties in the subsurface reservoir. Emphasis is placed on the testing of small samples of rocks to uncover their physical properties and their interactions with various fluids. A considerable body of knowledge of rocks and their fluid flow properties has been obtained from studies of artificial systems such as networks of pores etched on glass plates, packed columns of glass beads, and from outcrop samples of unconsolidated sands, sandstones, and limestones. These studies have been used to develop an understanding 1 2 PETROPHYSICS RESERVOIR ROCK PROPERTIES of the petrophysical and fluid transport properties of the more complex subsurface samples of rocks associated with petroleum reservoirs. This body of experimental data and production analyses of artificial systems, surface rocks, and subsurface rocks make up the accumulated knowledge of petrophysics. Although the emphasis of this text is placed on the analyses of small samples, the data are correlated to the macroscopic perance of the petroleum reservoirs whenever applicable. In considering a reservoir as a whole, one is confronted with the problem of the distribution of these properties within the reservoir and its stratigraphy. The directional distribution of thickness, porosity, permeability, and geologic features that contribute to heterogeneity governs the natural pattern of fluid flow. Knowledge of this natural pattern is sought to design the most efficient injection-production system for economy of energy and maximization of hydrocarbon production [ 13. Petrophysics is intrinsically bound to mineralogy and geology because the majority of the world’s petroleum occurs in porous sedimentary rocks. The sedimentary rocks are composed of fragments of other rocks derived from mechanical and chemical deterioration of igneous, metamorphic, and other sedimentary rocks, which is constantly occurring. The particles of erosion are frequently transported to other locations by winds and surface streams and deposited to new sedimentary rock structures. Petrophysical properties of the rocks depend largely on the depositional environmental conditions that controlled the mineral composition, grain size, orientation or packing, amount of cementation, and compaction. MINERAL CONSTITUENTS OF ROCKS-A REVIEW The physical properties of rocks are the consequence of their mineral composition. Minerals are defined here as naturally occurring chemical elements or compounds ed as a result of inorganic processes. The chemical analysis of six sandstones by emission spectrography and X-ray dispersive scanning electron microscopy [2] showed that the rocks are composed of just a few chemical elements. Analysis of the rocks by emission spectroscopy yielded the matrix chemical composition since the rocks were fused with lithium to make all of the elements soluble in water, and then the total emission spectrograph