Page 10 - Basic Well Log Analysis for Geologist

Table of Contents:
1. Basic Relationships of Well Log Interpretation ........... 0c cece cece cece e nett eee eee e ee eee eens 1
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Introduction 20. ee eee 1
Borehole Environment ........0..00 0000 cc ener 2
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Invasion and Resistivity Profiles ....... 00.2 cece eee 4
Formation Temperature 2.00.00... eect eee eee e eee 5
2. The Spontaneous Potential Log «1.2.0.0... ccc cee cece eee e eee e eee e nent eeeeeees 28
Formation Water Resistivity (R,,) Determined ........0..000 28
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Shale
Volume 2... centr eet ens 40
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3. Resistivity Logs... 6. ccc eee cee eee ee eee eee eee nee e eee eee eee eee ee een eet teers 41
Induction Electric Log 2... eet rete eee 4!
Dual Induction Focused Log «2.2... eee eee 42
Laterolog* oo ee ee etree enter teens 43
Dual Laterolog-Microspherically Focused Log* 22.000. ees 43
Microlog*® 20. eee renee tebe eee eee 43
Microlaterolog* and Proximity Log* 2.0.0.0... 00. cette eee 44
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Resistivity Derived Porosity 2.0.0... 000. tence eee 44
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4. Porosity LOgS 2... ccc ccc ccc eee ee eee eee eee eee eee eee eee e teeter eee teen eeeeeseee 66
Sonic Log 2. tenet eee eee tee eee 66
Density Log... ete e teens 66
Neutron Log 2. ee Denne eee ete eee 67
Combination Neutron-Density Logo... 0. ett teen teens 68
5. Gamma Ray Log «2... occ cee eee ee eee eee e eee eee eee nett e nen eens 91
Volume of Shale Calculation 2.0.0.0 0 oe eee e bbb ee eee 91
6. Log Interpretation 20.2.0... cee ccc ccc cee eee eee eee e eee ee nee tee ee bene teen eeeneeeees 96
Archie Equation... eet 96
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Ratio Method 20. eee eee bette eee 96
Bulk Volume Water. .0 0. eee ee eee e beeen eee 98
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Quick Look Methods 2.0... eben 98
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Pickett Crossplot Method . 2.2.2.0... 0. ete tee 100
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1 STOR Cook GU COX) 101
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Permeability Logs 1.0... ener t ete t eee 102
Shaly Sand Analysis 2.0... 000. eee eee ee ete eee ee 103
7. Lithology Logging and Mapping Techniques ............. 00. cece eee eee cece eee etree eee e eee eaes 118
Combination Gamma Ray Neutron Density Log... 2... teen eee 118
M-N* Lithology Plot... 0.02 ene ee 118
MID* Lithology Plot 2.0... eer e ete etree tenes 118
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Alpha Mapping from SPLog 2.0... keene eee 119
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Clean Sand or Carbonate Maps from Gamma Ray Log... 2 nets 120
Rock Typing and Facies Mapping 2.2... eee teens 120
8. Log Interpretation Case Studies ......... 0... cece cece ce ce eee eee tee e ee eee eee cece teen ee eees 140
Pennsylvanian Atoka Sandstone, Permian Basin
Mississippian Mission Canyon Formation, Williston Basin
Eocene Wilcox Sandstone, Gulf Coast
Pennsylvanian Upper Morrow Sandstone, Anadarko Basin
Cretaceous Pictured Cliffs Sandstone, San Juan Basin
Devonian Hunton Formation, Anadarko Basin
Appendices of Charts Used in Plotting ...............eees eee eee ce eee eee e eee e eet e stern eeens 209
References 2.0... ccc cee ccc eee ee ee ee een eee eee eee eee eee eee eee e ene scenes 213
INdeX 2... ec cc ce ee ee ee eee nee ene ee enn ee be eee nee eee eee eee eet ee eee seen se neeees 215