FIGURES 1. Grand Canyon 1 2. Cutaway view of Earth 2 3. Geologic time 3 4. Major tectonic features of the earth's crust 4 5. Relative thickness and specific gravity of seafloor and continental crust 5 6. Burial and consolidation of sediments into rock 5 7. Rifting of continental crust 6 8. Subduction of oceanic crust 7 9. The rock cycle 7

10. Cementation of sediment 9 11. Depositional environments 10 12. Unsorted sediments 11 13. Sorted sediments 11 14. Graded sediments 11 15. Depositional layers along a stream bank 12 16. Alluvial fan 12 17. Depositional environments of the seashore 13 18. Marine delta 13 19. Mississippi River delta 14 20. Shale 14 21. Epeiric seas of North America in the Paleozoic era 15 22. Clastic and crystalline texture 15 23. Conglomerates 16 24. Sandstone 16 25. Freshly deposited and deeply buried and compacted clay 17 26. Oolitic limestone 17 27. Model of Permian Basin coral reef 18 28. El Capitan peak in West Texas 18 29. Salt dome 19 30. Topographic contour map 22 31. Geologic outcrop map 22 32. Structure contour map 23 33. Isopach map 23 34. Lithofacies map 23 35. Section 24 36. Block diagram 24 37. Law of original horizontality 25 38. Block diagram showing relative ages of features 26 39. Rock layers folded by horizontal compression 26 40. Anticline and synclines 27 41. Normal and reverse, or thrust, faults 27 42. Overthrust fault 28 43. Lateral, or strike-slip, fault 28 44. Growth faults 28 45. Disconformities 28

46. Angular unconformity 29 47. Nonconformity 29 48. Hydrocarbon molecules 32 49. Shallow marine biotic community 33 50. Relationship of burial depth to oil and gas generation 34 51. Primary hydrocarbon migration 34 52. Permeability versus porosity 35 53. Secondary hydrocarbon migration 35 54. Hydrocarbon seeps 36 55. Anticline trap 36 56. Fault trap 36 57. Faulted anticline traps 37 58. Rollover anticline and growth fault traps 37 59. Stratigraphic traps 38 60. Lens traps 38 61. Shoestring sand 39 62. Traps associated with a limestone reef 39 63. Hydrocarbon accumulation from source beds above and below an unconformity 40 64. Hydrocarbon traps around a salt diapir 40 65. Closure in an anticline trap 41 66. Hydrodynamically tilted oil-water contact 41 67. Gravity anomaly map of Lake Superior 45 68. Magnetic contour map of northern Alaska 45 69. Seismic ray paths 46 70. Seismic record section 47 71. Cuttings 48 72. Core sample 48 73. Lowering a logging sonde into the hole 48 74. Caliper device and caliper log presentation 49 75. Composite log chart 50 76. Correlation 51 7 7. Variations in hole diameter caused by differences in sedimentary rock layers 54 78. Bit drift in nonhorizontal formations 55 79. Pipe stuck in sloughing hole 55 80. Stuck pipe caused by swollen shale 56 81. Lost circulation 56 82. Differential sticking caused by slow loss of drilling fluid 56 83. Hydrostatic pressures in a wellbore and in a formation 57 84. Formation fluid entering wellbore from a high-pressure formation 58 85. Effects of hydraulics on hole bottom 60 86. Conventional completion 60 87. Types of hydrocarbon reservoirs 64 88. Oil-water contact, or transition, zone 65 89. Solution-gas drive reservoir 66 90. Production data from a solution-gas reservoir 67 91. Gas-cap drive reservoir 68 92. Production data from a gas-cap reservoir 68

93. Water drive reservoir 69 94. Production data from a water drive reservoir 70 95. Coning of water into a well 70 96. Irregular water encroachment and early breakthrough in rocks of high permeability 70 97. Edgewater drive reservoir 71 98. Bottom-water drive reservoir 71 99. Combination water and gas-cap drive 71

100. Production data from a water drive reservoir showing sensitivity to production rate 73 101. Radial flow and pressure patterns in reservoir around producing well 73 102. Pressures in a producing well 74 103. Effect of gas production on tubinghead pressure 74 104. Effect of water production on well pressure 75

TABLES

1. Depositional Environments 12

2. Clastic Sedimentary Rocks Classified by Grain Size 16

3. Recommended Weight/Speed Combinations for Insert Bits 59