Formation Testing –
Supercharge, Pressure Testing and Contamination Models
December 2018
by
Wilson C. Chin, Ph.D., M.I.T.
Table of Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vi
Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii
1. Formation Testing – Strategies, Capabilities and Solutions . . 1
1.1 Development Perspectives . . . . . . . . . . . . . . . . . . . 1
1.2 Basic Forward and Inverse Models . . . . . . . . . . . . . 4
1.3 Supercharge Forward and Inverse Models . . . . . . . . . 14
1.4 Multiple Drawdown and Buildup Inverse Models . . . . . 20
1.5 Multiphase Cleaning and Supercharge Model . . . . . . . 24
1.6 System Integration and Closing Remarks . . . . . . . . . 29
1.7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2. Supercharging – Forward Models and Inverse Solutions . . . . 31
2.1 Supercharge and Math Model Development . . . . . . . . 31
2.2 Supercharge Pressure and Ultimate Decay . . . . . . . . . 34
2.3 United States Patent 7,243,537 B2 . . . . . . . . . . . . . . 37
2.4 Forward and Inverse Models with Supercharging –
Drawdown-Only and Drawdown-Buildup Applications
and Illustrative Examples . . . . . . . . . . . . . . . . . . . 69
2.4.1 General Ideas in Formation Testing
Formulations . . . . . . . . . . . . . . . . . . . . . . . 69
2.4.2 Mathematical Formulation . . . . . . . . . . . . . . . 73
2.5 Drawdown Only Applications . . . . . . . . . . . . . . . . . 78
2.5.1 Example DD-1, High Overbalance . . . . . . . . . . 78
2.5.2 Example DD-2, High Overbalance . . . . . . . . . . 84
2.5.3 Example DD-3, High Overbalance . . . . . . . . . . 88
2.5.4 Example DD-4, Qualitative Pressure Trends . . . . 92
2.5.5 Example DD-5, Qualitative Pressure Trends . . . . 95
2.5.6 Example DD-6, "Drawdown-Only" Data with Multiple
Inverse Scenarios for 1 md/cp Application . . . . . 97
2.5.7 Example DD-7, "Drawdown-Only" Data with Multiple
Inverse Scenarios for 0.1 md/cp Application . . . . 102
2.6 Drawdown – Buildup Applications . . . . . . . . . . . . . 107
2.6.1 Example DDBU-1, Drawdown-Buildup, High
Overbalance . . . . . . . . . . . . . . . . . . . . . . . 107
2.6.2 Example DDBU-2, Drawdown-Buildup, High
Overbalance . . . . . . . . . . . . . . . . . . . . . . . 111
2.6.3 Example DDBU-3, Drawdown-Buildup, High
Overbalance . . . . . . . . . . . . . . . . . . . . . . . 114
2.6.4 Example DDBU-4, Drawdown-buildup, 1 md/cp
Calculations . . . . . . . . . . . . . . . . . . . . . . . 118
2.6.5 Example DDBU-5, Drawdown-buildup, 0.1 md/cp
Calculations . . . . . . . . . . . . . . . . . . . . . . . 122
2.7 Supercharged Anisotropic Flow Simulation Model . . . . 127
2.8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
3. Pressure Transient Analysis – Multirate Drawdown and
Buildup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 132
3.1 Multirate Drawdown and Buildup Applications . . . . . . 133
3.1.1 Monitoring, Testing, Treatment and Retest . . . . 134
3.1.2 Hydrate Characterization and Production . . . . . 138
3.2 Detailed Validations with Exact Solutions . . . . . . . . . 142
3.2.1 Validation of PTA-App-01 Inverse Model . . . . 144
3.2.2 Validation of PTA-App-02 Inverse Model . . . . 148
3.2.3 Validation of PTA-App-03 Inverse Model . . . . 156
3.2.4 Validation of PTA-App-04 Inverse Model . . . . 163
3.2.5 Validation of PTA-App-05 Inverse Model . . . . 172
3.2.6 Validation of PTA-App-06 Inverse Model . . . . 177
3.2.7 Validation of PTA-App-07 Inverse Model . . . . 182
3.2.8 Validation of PTA-App-08 Inverse Model . . . . 187
3.2.9 Validation of PTA-App-09 Inverse Model . . . . 192
3.2.10 Validation of PTA-App-10 Inverse Model . . . . 197
3.2.11 Validation of PTA-App-11 Inverse Model . . . . 202
3.3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 219
4. Practical Applications and Examples . . . . . . . . . . . . . . . 221
4.1 Review Objectives . . . . . . . . . . . . . . . . . . . . . . . 221
4.2 Practical Applications and Examples . . . . . . . . . . . . 222
4.2.1 Isotropic Medium Pressure Testing . . . . . . . . 222
4.2.1.1 Steady-state method . . . . . . . . . . . . 222
4.2.1.2 Drawdown-buildup method . . . . . . . . 226
4.2.1.3 Drawdown only method . . . . . . . . . . 230
4.2.2 Anisotropic Media Pressure Testing
(Using FT-01) . . . . . . . . . . . . . . . . . . . . . 232
4.2.3 Supercharge Effects in Drawdown-Buildup . . . 240
4.2.4 Supercharge Mechanics in Detail –
Reservoir Fluid More Viscous Than Mud . . . . . 250
4.2.5 Supercharge Mechanics in Detail –
Reservoir Fluid Less Viscous Than Mud . . . . . 261
4.2.6 Supercharge Mechanics in Detail –
Reservoir Fluid Viscosity Equals Mud
Viscosity . . . . . . . . . . . . . . . . . . . . . . . . 264
4.2.7 Perfectly Balanced Well, Mechanics in Detail –
Reservoir Fluid Viscosity Equals Mud
Viscosity . . . . . . . . . . . . . . . . . . . . . . . . 266
4.2.8 Underbalance Mechanics in Detail –
Reservoir Fluid Viscosity Equals Mud
Viscosity . . . . . . . . . . . . . . . . . . . . . . . . 268
4.2.9 Comparing Overbalance vs Underbalance
Pressures for Same Reservoir and Tool Pumping
Conditions . . . . . . . . . . . . . . . . . . . . . . . 270
4.2.10 Consequences of Non-Performing Pump Piston . 284
4.2.11 Batch Processing Using FT-00 . . . . . . . . . . . 291
4.2.12 Depth of Investigation Using FT-00 DOI
Function . . . . . . . . . . . . . . . . . . . . . . . . . 296
4.2.13 History Matching Using FT-06 Batch Mode . . . 306
4.2.13.1 Operating FT-06 batch simulator . . . . 308
4.2.13.2 Source code documentation
(color coded) . . . . . . . . . . . . . . . . 313
4.2.13.3 A final example – concise operational
summary . . . . . . . . . . . . . . . . . . 328
4.2.14 Gas Pumping . . . . . . . . . . . . . . . . . . . . . . 334
4.2.14.1 Several field notes . . . . . . . . . . . . 334
4.2.14.2 Review of steady-state direct and inverse
methods . . . . . . . . . . . . . . . . . . . 335
4.2.14.3 Transient gas calculations . . . . . . . . 338
4.3 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 342
5. Best Practices and Closing Remarks . . . . . . . . . . . . . . . . 343
5.1 Best Practices . . . . . . . . . . . . . . . . . . . . . . . . . . 343
5.2 Recommended Reading . . . . . . . . . . . . . . . . . . . . 351
Cumulative References . . . . . . . . . . . . . . . . . . . . . . . . . 352
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 363
About the Author . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 369