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<p>Foreword xi</p> <p>Preface xiii</p> <p>Acknowledgments xv</p> <p>Introduction 1</p> <p><b>Part 1 Natural Fractures 9</b></p> <p><b>Section A Extension Fractures 11</b></p> <p>A1 High‐Angle Extension Fractures 13</p> <p>A1a Introduction 13</p> <p>A1b Fractography of High‐Angle Extension Fractures 14</p> <p>A1c Extension Fracture Dimensions 21</p> <p>A1d Extension Fracture Variations and Lithologic Influences 33</p> <p>A1e High‐Angle Extension Fracture Intersections 43</p> <p>A1f High‐ Angle Extension Fractures in Deviated Core 47</p> <p>A2 Inclined Extension Fractures 51</p> <p>A2a Inclined Extension Fractures in Horizontally Bedded Strata 51</p> <p>A2b Inclined Extension Fractures in Inclined Strata 53</p> <p>A2c Vertical Extension Fractures in Inclined Strata 54</p> <p>A3 Horizontal Extension Fractures 55</p> <p>A3a Beef‐Filled Fractures 55</p> <p>A3b Other Calcite‐Mineralized Horizontal Extension Fractures 57</p> <p>A3c NOT Horizontal Extension Fractures 57</p> <p><b>Section B Shear Fractures 59</b></p> <p>B1 Introduction 61</p> <p>B1a Nomenclature 61</p> <p>B1b Anderson’s Shear Fracture/Fault Classification 62</p> <p>B2 Shear Fracture Dimensions 65</p> <p>B3 Shear Fracture Fractography 67</p> <p>B3a Slickensides, Slickenlines, and Accretionary Steps 67</p> <p>B3b En Echelon Segments 69</p> <p>B3c Steps 71</p> <p>B3d Pinch and Swell 72</p> <p>B3e Sheared and Glassy Surfaces 75</p> <p>B3f Slickencrysts 75</p> <p>B3g Other Evidence for Shear 76</p> <p>B4 High‐Angle Shear Fractures 79</p> <p>B4a Introduction 79</p> <p>B4b High‐Angle Strike‐Slip Shear Fractures 79</p> <p>B4c Non‐ Ideal High‐Angle Shear Fractures 82</p> <p>B5 Intermediate‐Angle Shear Fractures 85</p> <p>B6 Low‐Angle Shear Fractures 89</p> <p>B7 Bed‐Parallel Shear Fractures 93</p> <p>B8 Deformation Bands 97</p> <p>B9 Faults 101</p> <p><b>Section C Other Types of Natural Fractures 105</b></p> <p>C1 Introduction 107</p> <p>C2 Microfractures 109</p> <p>C3 Ptygmatically Folded Fractures 111</p> <p>C4 Fissures 117</p> <p>C5 Veins 119</p> <p>C6 Expulsion Structures 121</p> <p>C7 Syn‐Sedimentary Fractures 125</p> <p>C8 Compound/Reactivated Fractures 133</p> <p>C9 Shattered Rock 137</p> <p>C10 Karst Breccias 139</p> <p>C11 Pocket‐Size Geomechanical Systems 143</p> <p>C12 Stylolites 147</p> <p><b>Section D Mineralization 151</b></p> <p>D1 Mineralization 153</p> <p>D1a Introduction 153</p> <p>D1b Calcite Mineralization 154</p> <p>D1c Other Types of Mineralization 160</p> <p>D1d Oil and Bitumen 163</p> <p>D1e False Mineralization 167</p> <p><b>Part 2 Induced Fractures 171</b></p> <p>2A Introduction 173</p> <p>2B Petal and Saddle Fractures 175</p> <p>2C Centerline Fractures 185</p> <p>2D Disc Fractures 197</p> <p>2E Scribe‐Knife Fractures 209</p> <p>2F Torque and Helical Twist Fractures 213</p> <p>2G Core‐Compression Fractures 219</p> <p>2H Percussion‐Induced Fractures 221</p> <p>2I Bending Fractures with Barbs 225</p> <p>2J Irregular Crack Networks 229</p> <p>2K Induced Fractures with Curved Strikes 233</p> <p>2L Waterflood‐Related Fractures 237</p> <p>2M Cored Hydraulic Fractures 241</p> <p><b>Part 3 Artifacts 245</b></p> <p>3A Introduction 247</p> <p>3B Core Tops and Core Bases 249</p> <p>3C1 Core‐Catcher Drag 253</p> <p>3C2 Core Orientation Scribe Grooves 257</p> <p>3C3 Irregular Core Diameters 261</p> <p>3C4 Pinion Holes 263</p> <p>3D1 Spinoffs 265</p> <p>3D2 Twice‐Turned Core 269</p> <p>3E Saw Scars 271</p> <p>3F1 Core Plucking 277</p> <p>3F2 Scratches 279</p> <p>3F3 Drill‐Mud Erosion 281</p> <p>3F4 Core‐Parting Enigmas 283</p> <p>3F5 Polished Fracture Surfaces in Horizontal Cores 285</p> <p>3F6 Tip Polish 287</p> <p>3F7 Slab‐Plane Consistency 291</p> <p>3F8 Illusions 295</p> <p>3F9 Coring‐Related Rock Alteration on Core Surfaces 299</p> <p>Index 301</p>

"A high quality publication that should be an essential text in any and all core facilities and essential reading for anyone who spends time looking at core." <i>Geoscientist Online</i>

<p><b> John C. Lorenz</b> and <b>Scott P. Cooper</b> are Senior Geologists with FractureStudies LLC in Edgewood, New Mexico.

<p><b> An invaluable reference that helps geologists recognize and differentiate the many types of natural fractures, induced fractures and artefacts found in cores </b> <p><i> Atlas of Natural and Induced Fractures in Core</i> offers a reference for the interpretation of natural and induced fractures in cores. The natural and induced fracture data contained in cores provides a wealth of information once they are recognized and properly interpreted. Written by two experts in the field, this resource provides a much-needed tool to help with the accurate interpretation of these cores. <p> The authors include the information needed to identify different fracture types as well as the criteria for distinguishing between the types of fractures. The atlas shows how to recognize non-fracture artefacts in a core since many of them provide other types of useful information. In addition, the text's illustrated structures combined with their basic interpretations are designed to be primary building blocks of a complete fracture assessment and analysis. The authors show how to recognize and correctly interpret these building blocks to ensure that subsequent analyses, interpretations, and modeling efforts regarding fracture-controlled reservoir permeability are valid. <p> Presented in full color throughout, this comprehensive reference is written for geologists charged with interpreting fracture-controlled permeability systems in reservoirs as well as for students or other scientists who need to develop the skills to accurately interpret the natural and induced fractures in cores.

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