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CONTENTS About the Authors xviii Acknowledgment xx Preface to the First Edition xxi Preface to the Second Edition xxii i Units xxv CHAPTER 1 Introduction to Mineralogy · ·*·· 1 Mineral Constituents of Rocks-A Review, 2 Igneous Rocks, 7 Metamorphic Rocks, 9 Sedimentary Rocks, 10 Properties of Sedimentary Particles, 14 Development and Use of Petrophysics, 20 Objectives and Organization, 22 Problems, 24 Glossary (Chapter 1), 24 References, 26 CHAPTER 2 Introduction to Petroleum Geology 29 Review of Composition of the Globe, 29 Crust, 31 Plate Tectonics, 32 Geologic Time, 34 Sedimentary Geology, 37 Basins, 37 Divergent Continental Margins, 38 Convergent Continental Margins, 39 Transform Continental Margins, 39 Transgressive-Regressive Cycles, 39 Accumulation of Sediments, 40 Hydrocarbon Traps, 44 Origin of Petroleum, 46 Transformation of Organics Into Kerogen, 47 Transformation of Kerogen Into Oil and Gas, 48 Migration and Accumulation of Petroleum, 49 Primary Migration, 50 Secondary Migration, 51 Properties of Subsurface Fluids, 53 Hydrostatic Pressure Gradient, 54 Lithostatic Pressure Gradient, 54 Geothermal Gradient, 55 Oilfield Waters, 58 Petroleum, 65 Petroleum Chemistry, 71 Problems, 81 Nomenclature, 83 Greek Symbols, 84 Subscripts, 84 References, 85 CHAPTER 3 Porosity and Permeability 87 Porosity, 88 Factors Governing the Magnitude of Porosity, 89 Engineering Classification of Porosity, 91 Geological Classification of Porosity, 91 Visual Description of Porosity in Carbonate Rocks, 94 Fluid Saturation, 96 Quantitative Use of Porosity, 97 Permeability, 100 Classification of Permeability, 101 Factors Affecting the Magnitude of Permeability, 102 Permeability-Porosity Relationships, 105 Kozeny Correlation, 106 Concept of Flow Units, 112 Mathematical Theory of Flow Units, 114 Specific Surface Area, 116 Flow Unit Characterization Factors, 120 Effect of Packing on Permeability, 131 Effect of Water Saturation on Permeability, 132 Permeability from NMR Log, 134 Permeability-Porosity Relationships in Carbonate Rocks, 136 Directional Permeability, 147 Reservoir Heterogeneity, 159 Distribution of Rock Properties, 162 Permeability from Well Test Analysis, 167 viii Statistical Zonation Technique, 173 Problems, 178 Nomenclature, 184 Subscripts, 185 Superscripts, 186 Greek Symbols, 186 References, 186 CHAPTER 4 Formation Resistivity and Water Saturation 191 Formation Resistivity Factor, 192 Resistivity Measurement, 192 Determination of Formation Water Resistivity, 194 Correlation between FR and Porosity, 205 Correlations between FR and Tortuosity, 207 Correlations between FR and Cementation, 209 Theoretical Formula for FR, 212 Correlation between FR and Water Saturation, 217 Correlation between FR and Permeability, 227 Resistivity of Shaly (Clayey) Reservoir Rocks, 230 Water Saturation in Shaly (Clayey) Reservoir Rocks, 231 Approximate Shale Relationship, 237 Generalized Shale Relationship, 238 Flow Units for Shaly Sandstones, 240 Lab-Derived Evaluation of Shaly (Clayey) Reservoir Rocks, 244 Log-Derived Evaluation of Shaly (Clayey) Reservoir Rocks, 270 Formation Evaluation, 270 Core Analysis, 271 Well Log Analysis, 272 Problems, 288 Nomenclature, 292 Subscripts, 293 Greek Symbols, 294 References, 294 CHAPTER 5 Capillary Pressure 299 Capillary Pressure, 299 Derivation of the Capillary Pressure Equation, 300 Capillary Rise, 304 Capillary Pressure J-Function, 306 Semipermeable Disk Measurement of Capillary Pressure, 308 Measurement of Capillary Pressure by Mercury Injection, 310 Centrifuge Measurement of Capillary Pressure, 316 Laboratory Procedure, 316 Calculation of Centrifuge Capillary Pressure Data, 319 Limiting Centrifuge Speed, 320 ix Approximate Calculation of the Inlet Saturation, 322 Theoretically Exact Calculation of the Inlet Saturation, 324 Pore Size Distribution, 328 Vertical Saturation Profile in a Reservoir, 332 Capillary Number, 338 Problems, 341 Nomenclature, 342 Greek Symbols, 343 References, 343 CHAPTER 6 Wettability 347 Wettability, 347 Interfacial Tension, 348 Contact Angle, 349 Sessile Drop Measurement of Contact Angles, 351 Wilhelmy Plate Measurement of Contact Angles, 353 Surface Chemical Properties, 354 Evaluation of Wettability, 358 Amott Wettability Index, 358 Usbm Wettability Index, 360 Combined Amott-Usbm Wettability Test, 362 Spontaneous Imbibition Wettability Test, 364 Fluid Displacement Energy, 365 Water-Oil-Rock Interfacial Activity, 369 Effect of Wettability on Oil Recovery, 371 Effect of Brine Salinity on Oil Recovery, 376 Alteration of Wettability, 377 Treatment of the Rock, 377 Addition of Fluid-soluble Compounds to Water and Oil, 378 Aging the Oil-Brine-Rock System, 381 Effects of Temperature and Pressure, 382 Restoration of Original Wettability, 384 Effect of Wettability on Electrical Properties, 385 Problems, 390 Nomenclature, 391 Greek Symbols, 392 Subscripts, 393 References, 393 CHAPTER 7 Applications of Darcy's Law 403 Darcy's Law, 404 Linear Flow of Incompressible Fluids, 405 Linear Flow of Gas, 408 Darcy's and Poiseuille's Laws, 412 Linear Flow through Fractures and Channels, 413 Flow through Fractures, 414 Flow through Solution Channels, 419 Radial Flow Systems, 422 Steady-state Flow, 423 Pseudosteady-state Flow, 425 Radial Laminar Flow of Gas, 435 Turbulent Flow of Gas, 439 Linear Turbulent Flow, 439 Friction Factor of Porous Rocks, 447 Turbulent Radial Flow, 454 Multiple-Permeability Rocks, 457 Layered Reservoirs with Crossflow, 457 Layered Reservoirs without Crossflow, 458 Composite reservoirs, 462 Problems, 467 Nomenclature, 471 Greek symbols, 472 References, 472 CHAPTER 8 Naturally Fractured Reservoirs 477 Introduction, 477 Origin of Permeability in Carbonate Rocks, 479 Geological Classifications of Natural Fractures, 479 Engineering Classification of Naturally Featured Reservoir, 481 Indicators of Natural Fractures, 485 Visual Identification of Fractures, 488 Petrophysical Properties of Naturally Featured Rocks, 491 Fracture Porosity Determination, 491 Porosity Partitioning Coefficient, 494 Fracture Intensity Index, 498 Permeability-Porosity Relationships in Double Porosity Systems, 501 Porosity and Permeability Relationships in Type 1 Naturally Fractured Reservoirs, 504 Effect of Fracture Shape, 507 Hydraulic Radius of Fractures, 508 Type 2 Naturally Fractured Reservoirs, 510 Fluid Flow Modeling in Fractures, 512 Fracture Area, 512 Fracture Storage Capacity, 514 Fracture Conductivity, 514 Characterizing Natural Fractures from Well Test Data, 515 Problems, 523 Nomenclature, 524 Subscripts, 525 xi Greek Symbols, 526 References, 526 CHAPTER 9 Effect of Stress on Reservoir Rock Properties 529 Static Stress-Strain Relation, 530 Stress Analysis, 530 Strain Analysis, 533 Two-dimensional Stress-strain Systems, 535 Rock Deformation, 536 Hooke's Law, 537 Stress-strain Diagrams, 546 The Mohr Diagram, 549 Dynamic Elastic Properties, 552 Rock Strength and Hardness, 555 Compressibility of Porous Rocks, 561 Pore Compressibility, 561 Effectiveness of Pore Pressure in Countering Stress, 566 Effect of Pore Compressibility on Reserves Calculations, 569 Converting Lab Data to Reservoir Data, 571 Effect of Stress on Core Data, 574 Effect of Stress on Porosity, 575 Effect of Stress on Permeability, 578 Effect of Stress On Resistivity, 579 Porosity-Permeability-Stress Relationship, 581 Effect of Stress on Fracturing, 595 Effect of Poisson's Ratio on Fracture Gradient, 596 Effect of Poisson's Ratio on Fracture Dimensions, 607 In-Situ Stress Distribution, 612 Effect of Stress Change on Rock Failure, 618 Change in Stress Field due to Depletion and Repressurization, 619 Stress Relationship at the Wellbore, 620 Estimating Critical Borehole Pressure in Vertical Wells, 621 Critical Borehole Pressure in Horizontal Wells, 622 Critical Pore Pressure, 624 Example of a North Sea Reservoir, 625 Porosity as Strength Indicator to Evaluate Sand Production, 628 Problems, 633 Nomenclature, 637 Subscripts, 638 Greek Symbols, 639 References, 639 CHAPTER 10 Fluid-Rock Interactions 645 Importance of Near-Wellbore Permeability, 645 Nature of Permeability Damage, 648 Origin of Permeability Damage, 649 Types of Permeability Damage, 651 Effect of Fines Migration and Permeability, 659 Types and Sizes of Fines, 660 Fines Migration, 669 Migration of Foreign Solids, 683 Critical Velocity Concept, 683 Entrainment and Surface Deposition, 684 Entrainment and Plugging, 688 Identification of Permeability Damage Mechanisms, 693 Permeability Damage from Foreign Solids, 694 Permeability Damage from Formation Fines, 700 Effect of Water Quality on Permeability, 705 External Filter Cake Buildup, 708 Internal Filter Cake Buildup, 710 Injectivity Decline from Plugging of Perforations, 714 Impairment From Wellbore Fillup, 716 Membrane Filtration Tests, 718 Core Filtration Tests, 721 Problems, 730 Nomenclature, 731 Subscripts, 732 Symbols, 732 References, 733 APPENDIX Measurement of Rock and Fluid Properties 737 EXPERIMENT 1 Fluid Content of Rocks by the Retort Method 738 Introduction, 738 Equipment and Procedures, 739 Equipment, 739 Retort Specimen, 739 Retort Calibration, 740 Retorting, 740 Sample Calculations, 740 Retort Calibration, 740 Results from the Test Specimen, 741 Saturation Calculations, 741 Questions and Problems, 741 References, 742 EXPERIMENT 2 Measurement of Saturation by Extraction 743 Introduction, 743 Equipment and Procedures, 744 Sample Calculations, 745 Questions and Problems, 745 References, 746 EXPERIMENT 3 Density, Specific Gravity, and API Gravity 747 Introduction, 747 Equipment and Procedures, 748 Measurement of API Gravity, 748 Westphal Balance, 749 Questions and Problems, 750 References, 750 EXPERIMENT 4 Specific Gravity of Gases 751 Introduction, 751 Equipment and Procedures, 751 Sample Calculations, 753 Questions and Problems, 753 References, 753 EXPERIMENT 5 Viscosity 754 Introduction, 754 Equipment and Procedures, 754 Cannon-Fenske Viscometer, 755 Questions and Problems, 757 References, 757 EXPERIMENT 6 Fluorescence 758 Introduction, 758 Equipment and Procedures, 759 Questions and Problems, 760 References, 760 EXPERIMENT 7 Absolute and Effective Porosity 761 Introduction, 761 Equipment and Procedures, 762 Absolute Porosity from Grain Volume, 762 Grain and Bulk Volumes, 763 Effective Porosity, 764 Summary, 764 Porosity Measurement by Mercury Injection, 764 Porosity Measurement by Gas Compression/Expansion, 765 Statistical Evaluation of Porosity Data, 768 Questions and Problems, 771 References, 771 EXPERIMENT 8 Particle Size Distribution 772 Introduction, 772 Equipment and Procedures, 772 Sieve Analysis Procedure, 775 Questions and Problems, 777 References, 777 EXPERIMENT 9 Surface Area of Sediments 778 Introduction, 778 Equipment and Procedure, 779 Questions and Problems, 785 References, 785 EXPERIMENT 10 Absolute Permeability 787 Introduction, 787 Equipment and Procedures, 788 Absolute Permeability Using a Liquid, 788 Absolute Permeability Using a Gas, 789 Effect of Overburden Pressure on Absolute Permeability, 791 Sample Calculations, 791 Run 1, 792 Run 2, 792 Sample Calculation 1, 793 Sample Calculation 2, 794 Questions and Problems, 794 References, 795 EXPERIMENT 11 Verification of the Klinkenberg Effect 796 Introduction, 796 Equipment and Procedures, 796 Sample Calculations, 797 Experimental Data, 797 Questions and Problems, 799 References, 799 EXPERIMENT 12 Relative Permeability 800 Introduction, 800 Steady-State Method, 801 Unsteady-State Method, 802 Equipment and Procedures, 802 Questions and Problems, 807 References, 808 EXPERIMENT 13 Basic Well Log Petrophysical Parameters 809 Introduction, 809 Equipment and Procedures, 811 Resistivity of the Formation Water, 811 Rock Resistivity Saturated with Brine, 811 Sample Calculations, 813 Questions and Problems, 814 References, 814 EXPERIMENT 14 Surface and Interfacial Tensions 815 Introduction, 815 Equipment and Procedures, 815 Sample Calculations, 818 Questions and Problems, 818 References, 819 EXPERIMENT 15 Capillary Pressure 820 Introduction, 820 Equipment and Procedures, 821 Core Preparation for Capillary Pressure Measurement, 821 Mercury Injection Method, 822 Porous Diaphragm Method, 822 Centrifuge Method, 824 Sample Calculations, 830 Questions and Problems, 832 References, 835 EXPERIMENT 16 Pore Size Distribution 836 Introduction, 836 Equipment and Procedures, 837 Sample Calculations, 838 Questions and Problems, 838 References, 839 EXPERIMENT 17 Determination of Z-Factors for Imperfect Gases 840 Introduction, 840 Van Der Waals' Equation, 842 Equipment and Procedures, 843 Questions and Problems, 843 References, 844 EXPERIMENT 18 Basic Sediment and Water (Bs&W) 845 Introduction, 845 Equipment and Procedures, 845 Questions and Problems, 846 References, 846 EXPERIMENT 19 Point-Load Strength Test 847 Introduction, 847 Equipment and Procedures, 847 Sample Calculations, 848 Questions and Problems, 849 References, 849 EXPERIMENT 20 Utilities 850 Preservation of Cores, 850 Dead-Weight Tester, 851 Procedure, 852 References, 852 ABOUT THE AUTHORS Djebbar Tiab is the Senior Professor of Petroleum Engineering at the University of Oklahoma, and Petroleum Engineering consultant. He received his B.Sc. (May 1974) and M.Sc. (May 1975) degrees from the New Mexico Institute of Mining and Technology, and his Ph.D. degree (July 1976) from the University of Oklahoma-all in petroleum engineering. He is the Director of the University of Oklahoma Graduate Program in Petroleum Engineering in Algeria. At the University of Oklahoma, he taught fifteen different petroleum and general engineering courses including: well test analysis, petrophysics, oil reservoir engineering, natural gas engineering, and properties of reservoir fluids. Dr. Tiab has consulted for a number of oil companies and offered training programs in petroleum engineering in the USA and overseas. He worked for over two years in the oilfields of Algeria for Alcore, S.A., an association of Sonatrach and Core Laboratories. He has also worked and consulted for Core Laboratories and Western Atlas in Houston, Texas, for four years as a Senior Reservoir Engineer Advisor. As a researcher at the University of Oklahoma, he received several research grants and contracts from oil companies and various U.S. agencies. He supervised 23 Ph.D. and 94 M.S. students at the University of Oklahoma. He is the author of over 150 conference and journal technical papers. In 1975 (M.S. thesis) and 1976 (Ph.D. dissertation) he introduced the pressure derivative technique, which revolutionized the interpretation of pressure transient tests. He developed two patents in the area of reservoir characterization (identification of flow units). Dr. Tiab is a member of the U.S. Research Council, Society of Petroleum Engineers, Core Analysis Society, Pi Epsilon Tau, Who is Who, and American Men and Women of Science. He served as a technical editor of various SPE, Egyptian, Kuwaiti and U.A.E. journals, and as a member of the SPE Pressure Analysis Transaction Committee. He is a member of the SPE Twenty-Five Year Club. He has received the Outstanding Young Men of America Award, the SUN Award for Education Achievement, the Kerr-McGee Distinguished Lecturer Award, the College of Engineering Faculty Fellowship of Excellence, the Halliburton Lectureship Award, the UNOCAL Centennial Professorship, and the P&GE Distinguished Professor. Dr. Tiab has been elected in October 2002 to the Russian Academy of Natural Sciences as a foreign member because of "his outstanding work in petroleum engineering." He was also awarded in October 2002 the Kapista gold Medal of Honor for "his outstanding contributors to the field of engineering." He received the prestigious 1995 SPE Distinguished Achievement Award for Petroleum Engineering Faculty. The citation read, "He is recognized for his role in student development and his excellence in classroom instruction. He pioneered the pressure derivative technique of well testing and has contributed considerable understanding to petrophysics and reservoir engineering through his research and writing." Erle C. Donaldson began his career as a pilot plant project manager for Signal Oil and Gas Research in Houston, Texas. Later he joined the U.S. Bureau of Mines Petroleum Research Center in Bartlesville, Oklahoma, as a project manager of subsurface disposal and industrial wastes and reservoir characterization; 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. 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 methods 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 deformation, 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 formation damage. Finally, a set of 19 laboratory procedures for determination of the rock and fluid properties, scxi and rock- fluid interac tions- which are present ed in the eight chapter s of the book- are include d in an Appen dix. In additio n to detaile d experi mental proced ures, the authors have include d exampl es for each experi ment. Althou gh this book was primari ly organiz ed and prepar ed for use as a textbo ok and laborat ory manual , it also will serve as a referen ce book for petrole um engine ers and geologi sts, and can be used in petroph ysical testing laborat ories. It is the first compre hensive book publish ed on the subject since I960 (J. W. Amyx, D. M. Bass, Jr., and R. L. Whitin g, Petrole um Reserv oir Engine ering, McGra w-Hill, New York, NY). The book also can serve as the basis for the advanc ement of theorie s and applica tions of petroph ysics as the technol ogy of petrole um engine ering continu es to improv e and evolve. This unique book belong s on the booksh elf of every petrole um engine er and petrole um geologi st. Djebba r Tiab Erle C. Donald son George V. Chiling ar PREF ACE TO THE SECO ND EDITI ON This second edition of Petrop hysics has been design ed to amplif y the first volume (from 8 to 10 chapter s) and comply with suggest ions from colleag ues and numero us readers who were genero us in taking time to convey their advice. Read ers will find that the first chapter , an introdu ction to minera logy, has been conside rably amplifi ed to assist in better recogni tion of the multitu de of mineral s and rocks. There was no noticea ble change to Chapte r 2 (Introd uction to Petrole um Geolog y), Chapte r 7 (Applic ations of Darcy's Law), or Chapte r 10 (Fluid- Rock Interact ions). Cha pter 3 (Porosi ty and Permea bility) underw ent major change s. The followi ng topics were added: concep t of flow units, directi onal permea bility, correlat ions betwee n horizon tal and vertical permea bility, averagi ng techniq ues, Dykstr a- Parson s coeffici ent of permea bility variatio n, effectiv e permea bility from cores and well test data, and several more examp les. Chapte r 4 (Format ion Resistiv ity and Water Saturati on) was amplifi ed, mainly to include the charact erizatio n and identifi cation of flow units in shaly formati ons, and more exampl es. Chapte r 5 of the first edition was divided into two new chapter s: Chapte r 5 (Capill ary Pressur e) and Chapte r 6 (Wetta bility), becaus e of the large amount of work that has been conduc ted on wettabi lity since the publica tion of the first edition. Capilla ry pressur e and wettabi lity are, howeve r, bound togethe r becaus e much of the basis for various tests and theorie s of wettabi lity and its impact on oil recover y is based on capillar y pressur e behavi or as a functio n of fluid saturati on. It seems natural, therefo re, that a thorou gh underst anding of capillar y pressur e is necessa ry for the study of wettabi lity. Chap ter 8 (Natura lly Fractur ed Reserv oirs) is a new chapter . Practic ally all readers who contact ed us suggest ed that we include a more detaile d discuss ion of the petrop hysical aspects of natural ly fractur ed rocks. The main topics covere d in this chapter are: geologi cal and enginee ring classifi cations of natural fractur es, indicat ors of natural fractur es, determ ination of fractur e porosit y and permea bility, fracture intensit y index, porosit y partitio ning coeffici ent, and effect of fractur e shape on permea bility. A new concep t of hydraul ic radius of fractur e is introdu ced in this chapter . Metho ds for determ ining the fractur e storage capacit y and inter- porosit y from well test data are briefly discuss ed. Seve ral import ant topics were added to Chapte r 9 (Effect of Stress on Reserv oir Rock Proper ties): the effect of change in the stress field due to depleti on and repress urizatio n, stress and critical borehol e pressur e in vertical and horizon tal wells, critical pore pressur e, and estimat ion of unconfi ned compre ssive rock strengt h from porosit y data. The Appen dix, coverin g petroph ysics laborat ory experi ments, is essenti ally the same becaus e the basic method s for the experi mental study of petroph ysics have not change d very much. A recentl y develo ped general metho d for calcula tion of.relat ive permea bility, howev er, was include d in Experi ment 12. The proced ure is applica ble to both constan t rate and constan t pressur e unstead y state displac ement. Djebba r Tiab Erle C. Donald son UNITS Units of Area acre = 43,540 ft2 = 4046.9 m2 ft2 = 0.0929 m2 hectare = 10,000 m2 Constan ts Darcy = 0.9869 mm2 Gas constan t = 82.05 (atm x cm3)/(g mol x K) = 10.732 (psi x ft3)/(lb mol x °R) = 0.729 (atm x ft3)/(lb mol x °R) Mol. wt. of air = 28.97 Units of Length Angstrom = 1 x 10 8 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 Pressur e atm = 760 mm Hg (0°C) = 29.921 in. Hg = 14.696 psi atm = 33.899 ft water at 4°C bar = 14.503 3 psi = 0.987 atm = 0.1 MPa dyne/c m2 = 6.895 kPa (kilopa scal) f t water = 0.4912 psi kg(forc e)/cm2 = 14.223 psi psi = 2.036 in. Hg (0°C) = 6.895 kPa XXV Units of Temperature Degrees Fahrenheit (°F) = 1.8°C + 32 Degrees Rankine (°R) = 459.7 +°F Degrees Kelvin(K) = 273.16 +°C Units of Volume acre-ft = 43,560 ft3 = 7,758.4 bbl = 1.2335 x 103 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 molarity = mass of solute equal to the molecular ·weight per 1,000 grams of solvent normality = equivalent weight of solute per 1,000 grams of solvent (mass of solute equal to the molecular weight divided by the valence per 1,000 g of solvent) BIBLIOGRAPHY 1. Donaldson, E. C., Ewall, N. and Singh, B. "Characteristics of Capillary Pressure Curves." JPSE, No. 6, Nov. 1991, pp. 249-261. 2. Donaldson, E. C., Kendall, R. F., Baker, B. A. and Manning, F. S. "Surface Area Measurement of Geologic Materials. "JPSE, No. 15, Apr. 1975, pp. 111-116. 3. Worthington, A. E., Hedges, J. H. and Pallatt, N. "SCA Guidelines for Sample Preparation and Porosity Measurement of Electrical Resistivity Samples, Part I." The Log Analyst, Jan-Feb. 1990, pp. 20-28. 4. Lerner, D. B., Dacy, J. M., Raible, C. J., Rathmell, J. J., Swanson, G. and Walls, J. D. "SCA Guidelines for Sample Preparation and Porosity Measurement of Electrical Resistivity Samples, Part II." The Log Analyst, Mar-Apr. 1990, pp. 57-63.

Library of Congress Subject Headings for this publication: Petroleum Geology, Petrology