This book reviews strongly related subjects in wellbore pressure transient analysis for overbalanced and underbalanced drilling, static and dynamic filtration, single and multiphase flow, transient mudcake buildup and stuck-pipe assessment, describes existing models, and develops new fluid flow algorithms useful in modeling these flow effects.
>b?Wilson C. Chin earned his PhD from M.I.T. and his M.Sc. from Caltech. He has authored over twenty books with Wiley-Scrivener and other major scientific publishers, has more than four dozen domestic and international patents to his credit, and has published over one hundred journal articles, in the areas of reservoir engineering, formation testing, well logging, Measurement While Drilling, and drilling and cementing rheology. Inquiries: wilsonchin@aol.com.
Table of Contents1. Pressure Transient Analysis and Sampling in Formation
Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Pressure transient analysis challenges . . . . . . . . . . . . . . . 1
Background development . . . . . . . . . . . . . . . . . . . . . . . 3
1.1 Conventional Formation Testing Concepts . . . . . . . . . 5
1.2 Prototypes, Tools and Systems . . . . . . . . . . . . . . . . 6
1.2.1 Enhanced Formation Dynamic Tester
(EFDT ®) . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.2.2 Basic Reservoir Characteristic Tester
(BASIC-RCT™) . . . . . . . . . . . . . . . . . . . . . 13
1.2.3 Enhancing and enabling technologies. . . . . . . . . 15
Stuck tool alleviation . . . . . . . . . . . . . . . . . . 16
Field facilities. . . . . . . . . . . . . . . . . . . . . . . 17
1.3 Recent Formation Testing Developments . . . . . . . . . . 17
1.4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
2. Spherical Source Models for Forward and Inverse
Formulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
2.1 Basic Approaches, Interpretation Issues and Modeling
Hierarchies . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Early steady flow model . . . . . . . . . . . . . . . . . . . . 23
Simple drawdown-buildup models . . . . . . . . . . . . . . 23
Analytical drawdown-buildup solution. . . . . . . . . . . . 25
Phase delay analysis . . . . . . . . . . . . . . . . . . . . . . . 26
Modeling hierarchies . . . . . . . . . . . . . . . . . . . . . . 28
2.2 Basic Single-Phase Flow Forward and Inverse
Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.2.1 Module FT-00 . . . . . . . . . . . . . . . . . . . . . 36
2.2.2 Module FT-01 . . . . . . . . . . . . . . . . . . . . . 37
2.2.3 Module FT-03 . . . . . . . . . . . . . . . . . . . . . 38
2.2.4 Forward model application, Module FT-00 . . . . 39
2.2.5 Inverse model application, Module FT-01 . . . . . 41
2.2.6 Effects of dip angle . . . . . . . . . . . . . . . . . . 43
2.2.7 Inverse “pulse interaction” approach
using FT-00 . . . . . . . . . . . . . . . . . . . . . . . 46
2.2.8 FT-03 model overcomes source-sink
limitations . . . . . . . . . . . . . . . . . . . . . . . . 49
2.2.9 Module FT-04, phase delay analysis, introductory
for now. . . . . . . . . . . . . . . . . . . . . . . . . . 52
2.2.10 Drawdown-buildup, Module FT-PTA-DDBU . . 55
2.2.11 Real pumping, Module FT-06 . . . . . . . . . . . . 59
2.3 Advanced Forward and Inverse Algorithms . . . . . . . . . 61
2.3.1 Advanced drawdown and buildup methods
Basic steady model. . . . . . . . . . . . . . . . . . . 61
Validating our method. . . . . . . . . . . . . . . . . 63
2.3.2 Calibration results and transient pressure curves . 65
2.3.3 Mobility and pore pressure using first
drawdown data . . . . . . . . . . . . . . . . . . . . . 67
2.3.3.1 Run No. 1. Flowline volume 200 cc. . . . 68
2.3.3.2 Run No. 2. Flowline volume 500 cc. . . . 69
2.3.3.3 Run No. 3. Flowline volume 1,000 cc . . 71
2.3.3.4 Run No. 4. Flowline volume 2,000 cc . . 73
2.3.4 Mobility and pore pressure from last buildup
data . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
2.3.4.1 Run No. 5. Flowline volume 200 cc . . . 74
2.3.4.2 Run No. 6. Flowline volume 500 cc . . . 76
2.3.4.3 Run No. 7. Flowline volume 1,000 cc . . 77
2.3.4.4 Run No. 8. Flowline volume 2,000 cc . . 78
2.3.4.5 Run No. 9. Time-varying flowline volume
inputs from FT-07 . . . . . . . . . . . . . . 79
2.3.5 Phase delay and amplitude attenuation, anisotropic
media with dip – detailed theory, model and numerical
results. . . . . . . . . . . . . . . . . . . . . . . . . . . 81
2.3.5.1 Basic mathematical results . . . . . . . . . . 82
Isotropic model . . . . . . . . . . . . . . . . . 82
Anisotropic extensions . . . . . . . . . . . . 82
Vertical well limit . . . . . . . . . . . . . . . 83
Horizontal well limit . . . . . . . . . . . . . 83
Formulas for vertical and horizontal wells . 83
Deviated well equations. . . . . . . . . . . . 84
Deviated well interpretation for both
kh and kv . . . . . . . . . . . . . . . . . . . . 85
Two-observation-probe models . . . . . . . 86
2.3.5.2 Numerical examples and typical results . . 88
Example 1. Parameter estimates . . . . . . . 89
Example 2. Surface plots . . . . . . . . . . . 90
Example 3. Sinusoidal excitation . . . . . . 91
Example 4. Rectangular wave excitation . . 94
Example 5. Permeability prediction at general
dip angles . . . . . . . . . . . . . . . . . . . . 96
Example 6. Solution for a random input . . 98
2.3.5.3 Layered model formulation. . . . . . . . . . 99
2.3.5.4 Phase delay software interface . . . . . . . . 100
2.3.5.5 Detailed phase delay results in layered
anisotropic media. . . . . . . . . . . . . . . . 103
2.3.6 Supercharging and formation invasion introduction, with
review of analytical forward and inverse models . . 110
2.3.6.1 Development perspectives . . . . . . . . . . 111
2.3.6.2 Review of forward and inverse models . . . 113
FT-00 model . . . . . . . . . . . . . . . . . . 113
FT-01 model . . . . . . . . . . . . . . . . . . 117
FT-02 model . . . . . . . . . . . . . . . . . . 118
FT-06 and FT-07 models . . . . . . . . . . . 119
FT–PTA–DDBU model . . . . . . . . . . . . 122
Classic inversion model . . . . . . . . . . . . 123
Supercharge forward and inverse models . 123
Multiple drawdown and buildup inverse
models . . . . . . . . . . . . . . . . . . . . . . 129
Multiphase invasion, clean-up and
contamination. . . . . . . . . . . . . . . . . . 133
System integration and closing remarks . . 138
2.3.6.3 Supercharging summaries - advanced forward
and inverse models explored . . . . . . . . 139
Supercharge math model development . . . 139
Conventional zero supercharge model . . . 141
Supercharge extension. . . . . . . . . . . . . 142
2.3.6.4 Drawdown only applications . . . . . . . . . 144
Example DD-1. High overbalance . . . . . 144
Example DD-2. High overbalance . . . . . 150
Example DD-3. High overbalance . . . . . 154
Example DD-4. Qualitative pressure
trends . . . . . . . . . . . . . . . . . . . . . . 158
Example DD-5. Qualitative pressure
trends . . . . . . . . . . . . . . . . . . . . . . 161
Example DD-6. “Drawdown-only” data with
multiple inverse scenarios for 1 md/cp
application. . . . . . . . . . . . . . . . . . . . 163
Example DD-7. “Drawdown-only” data with
multiple inverse scenarios for 0.1 md/cp
application. . . . . . . . . . . . . . . . . . . . 168
2.3.6.5 Drawdown – buildup applications. . . . . . 173
Example DDBU-1. Drawdown-buildup, high
overbalance . . . . . . . . . . . . . . . . . . . 173
Example DDBU-2. Drawdown-buildup, high
overbalance . . . . . . . . . . . . . . . . . . . 177
Example DDBU-3. Drawdown-buildup, high
overbalance . . . . . . . . . . . . . . . . . . . 180
Example DDBU-4. Drawdown-buildup, 1 md/cp
calculations . . . . . . . . . . . . . . . . . . . 184
Example DDBU-5. Drawdown-buildup,
0.1 md/cp calculations . . . . . . . . . . . . 188
2.3.7 Advanced multiple drawdown – buildup (or, “MDDBU”)
forward and inverse models . . . . . . . . . . . . . . 193
2.3.7.1 Software description . . . . . . . . . . . . . . 193
2.3.7.2 Validation of PTA-App-11 inverse model . 200
2.3.8 Multiphase flow with inertial effects –
Applications to borehole invasion, supercharging,
clean-up and contamination analysis . . . . . . . . . 217
2.3.8.1 Mudcake dynamics. . . . . . . . . . . . . . . 217
2.3.8.2 Multiphase modeling in boreholes. . . . . . 220
2.3.8.3 Pressure and concentration displays. . . . . 222
Example 1. Single probe, infinite anisotropic
media. . . . . . . . . . . . . . . . . . . . 223
Example 2. Single probe, three layer medium . . . 228
Example 3. Dual probe pumping, three layer
medium . . . . . . . . . . . . . . . . . . 230
Example 4. Straddle packer pumping . . . . . . . . 231
Example 5. Formation fluid viscosity imaging . . . 233
Example 6. Contamination modeling . . . . . . . . 234
Example 7. Multi-rate pumping simulation. . . . . 234
2.4 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 236
3. Practical Applications Examples . . . . . . . . . . . . . . . . 237
3.1 Non-constant Flow Rate Effects . . . . . . . . . . . . . . . . 238
3.1.1 Constant flow rate, idealized pumping, inverse
method . . . . . . . . . . . . . . . . . . . . . . . . . . . 239
3.1.2 Slow ramp up/down flow rate . . . . . . . . . . . . . 245
3.1.3 Impulsive start/stop flow rate. . . . . . . . . . . . . . 250
Closing remarks . . . . . . . . . . . . . . . . . . . . . . . . . 255
3.2 Supercharging – Effects of Nonuniform Initial Pressure . 256
Conventional zero supercharge model . . . . . . . . . . . . 256
Supercharge “Fast Forward” solver . . . . . . . . . . . . . . 258
3.3 Dual Probe Anisotropy Inverse Analysis. . . . . . . . . . . 264
3.4 Multiprobe “DOI,” Inverse and Barrier Analysis . . . . . . 273
3.5 Rapid Batch Analysis for History Matching. . . . . . . . . 281
3.6 Supercharge, Contamination Depth and Mudcake Growth in
“Large Boreholes” – Lineal Flow . . . . . . . . . . . . . . . 289
Mudcake growth and filtrate invasion . . . . . . . . . . . . 289
Time-dependent pressure distributions . . . . . . . . . . . . 292
3.7 Supercharge, Contamination Depth and Mudcake Growth in
Slimholes or “Clogged Wells” – Radial Flow . . . . . . . . 292
3.8 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 294
4. Supercharge, Pressure Change, Fluid Invasion and
Mudcake Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . 295
Conventional zero supercharge model . . . . . . . . . . . . . . . 295
Supercharge model. . . . . . . . . . . . . . . . . . . . . . . . . . . 296
Relevance to formation tester job planning . . . . . . . . . . . . 298
Refined models for supercharge invasion . . . . . . . . . . . . . 299
4.1 Governing equations and moving interface modeling . . . 300
Single-phase flow pressure equations. . . . . . . . . . . . . 300
Problem formulation . . . . . . . . . . . . . . . . . . . . . . 303
Eulerian versus Lagrangian description . . . . . . . . . . . 303
Constant density versus compressible flow . . . . . . . . . 304
Steady versus unsteady flow . . . . . . . . . . . . . . . . . . 305
Incorrect use of Darcy’s law . . . . . . . . . . . . . . . . . . 305
Moving fronts and interfaces . . . . . . . . . . . . . . . . . 306
Use of effective properties . . . . . . . . . . . . . . . . . . . 308
4.2 Static and dynamic filtration . . . . . . . . . . . . . . . . . . 310
4.2.1 Simple flows without mudcake . . . . . . . . . . . . 310
Homogeneous liquid in a uniform linear core . . . . 311
Homogeneous liquid in a uniform radial flow. . . . 313
Homogeneous liquid in uniform spherical domain . 314
Gas flow in a uniform linear core . . . . . . . . . . . 315
Flow from a plane fracture . . . . . . . . . . . . . . . 317
4.2.2 Flows with moving boundaries . . . . . . . . . . . . 318
Lineal mudcake buildup on filter paper . . . . . . . 318
Plug flow of two liquids in linear core without
cake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 321
4.3 Coupled Dynamical Problems: Mudcake and Formation
Interaction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323
Simultaneous mudcake buildup and filtrate invasion in a linear
core (liquid flows) . . . . . . . . . . . . . . . . . . . . . . . . 323
Simultaneous mudcake buildup and filtrate invasion in a radial
geometry (liquid flows) . . . . . . . . . . . . . . . . . . . . . 327
Hole plugging and stuck pipe. . . . . . . . . . . . . . . . . . 330
Fluid compressibility . . . . . . . . . . . . . . . . . . . . . . 331
Formation invasion at equilibrium mudcake thickness . . 335
4.4 Inverse Models in Time Lapse Logging . . . . . . . . . . . 336
Experimental model validation. . . . . . . . . . . . . . . . . 336
Static filtration test procedure . . . . . . . . . . . . . . . . . 337
Dynamic filtration testing. . . . . . . . . . . . . . . . . . . . 337
Measurement of mudcake properties . . . . . . . . . . . . . 338
Formation evaluation from invasion data. . . . . . . . . . . 338
Field applications. . . . . . . . . . . . . . . . . . . . . . . . . 339
Characterizing mudcake properties . . . . . . . . . . . . . . 340
Simple extrapolation of mudcake properties . . . . . . . . 341
Radial mudcake growth on cylindrical filter paper . . . . . 342
4.5 Porosity, Permeability, Oil Viscosity and Pore Pressure
Determination. . . . . . . . . . . . . . . . . . . . . . . . . . . 345
Simple porosity determination . . . . . . . . . . . . . . . . . 345
Radial invasion without mudcake . . . . . . . . . . . . . . . 346
Problem 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348
Problem 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 350
Time lapse analysis using general muds . . . . . . . . . . . 351
Problem 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 352
Problem 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 353
4.6 Examples of Time Lapse Analysis . . . . . . . . . . . . . . 354
Formation permeability and hydrocarbon viscosity. . . . . 355
Pore pressure, rock permeability and fluid viscosity . . . . 357
4.7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360
5. Numerical Supercharge, Pressure, Displacement and
Multiphase Flow Models . . . . . . . . . . . . . . . . . . . . . 363
5.1 Finite Difference Solutions . . . . . . . . . . . . . . . . . . . 364
Basic formulas . . . . . . . . . . . . . . . . . . . . . . . . . . 364
Model constant density flow analysis. . . . . . . . . . . . . 366
Transient compressible flow modeling . . . . . . . . . . . . 369
Numerical stability. . . . . . . . . . . . . . . . . . . . . . . . 371
Convergence . . . . . . . . . . . . . . . . . . . . . . . . . . . 371
Multiple physical time and space scales . . . . . . . . . . . 372
Example 5-1. Lineal liquid displacement without
mudcake . . . . . . . . . . . . . . . . . . . . . 373
Example 5-2. Cylindrical radial liquid displacement without
cake. . . . . . . . . . . . . . . . . . . . . . . . 380
Example 5-3. Spherical radial liquid displacement without
cake. . . . . . . . . . . . . . . . . . . . . . . . 383
Example 5-4. Lineal liquid displacement without mudcake,
including compressible flow transients . . . 385
Example 5-5. Von Neumann stability of implicit time
schemes . . . . . . . . . . . . . . . . . . . . . 388
Example 5-6. Gas displacement by liquid in lineal core
without mudcake, including compressible flow
transients. . . . . . . . . . . . . . . . . . . . . 390
Incompressible problem. . . . . . . . . . . . 391
Transient, compressible problem . . . . . . 392
Example 5-7. Simultaneous mudcake buildup and
displacement front motion for incompressible
liquid flows . . . . . . . . . . . . . . . . . . 396
Matching conditions at displacement front . . . . . . . . . 399
Matching conditions at the cake-to-rock interface . . . . . 399
Coding modifications . . . . . . . . . . . . . . . . . . . . . . 400
Modeling formation heterogeneities. . . . . . . . . . . . . . 403
Mudcake compaction and compressibility . . . . . . . . . . 404
Modeling borehole activity . . . . . . . . . . . . . . . . . . . 405
5.2 Forward and Inverse Multiphase Flow Modeling. . . . . . 405
Problem hierarchies . . . . . . . . . . . . . . . . . . . . . . . 406
5.2.1 Immiscible Buckley-Leverett lineal flows without
capillary pressure. . . . . . . . . . . . . . . . . . . . . 407
Example boundary value problems . . . . . . . . . . 409
General initial value problem. . . . . . . . . . . . . . 410
General boundary value problem for infinite core . 411
Variable q(t) . . . . . . . . . . . . . . . . . . . . . . . 411
Mudcake-dominated invasion . . . . . . . . . . . . . 412
Shock velocity . . . . . . . . . . . . . . . . . . . . . . 412
Pressure solution . . . . . . . . . . . . . . . . . . . . . 414
5.2.2 Molecular diffusion in fluid flows. . . . . . . . . . . 415
Exact lineal flow solutions . . . . . . . . . . . . . . . 416
Numerical analysis. . . . . . . . . . . . . . . . . . . . 417
Diffusion in cake-dominated flows . . . . . . . . . . 419
Resistivity migration. . . . . . . . . . . . . . . . . . . 419
Lineal diffusion and “un-diffusion” examples . . . 420
Radial diffusion and “un-diffusion” examples . . . 423
5.2.3 Immiscible radial flows with capillary pressure and
prescribed mudcake growth . . . . . . . . . . . . . . 425
Governing saturation equation . . . . . . . . . . . . . 426
Numerical analysis. . . . . . . . . . . . . . . . . . . . 427
Fortran implementation . . . . . . . . . . . . . . . . . 429
Typical calculations . . . . . . . . . . . . . . . . . . . 429
Mudcake dominated flows . . . . . . . . . . . . . . . 435
“Un-shocking” a saturation discontinuity . . . . . . 438
5.2.4 Immiscible flows with capillary pressure and dynamically
coupled mudcake growth . . . . . . . . . . . . . . . . 441
Flows without mudcakes . . . . . . . . . . . . . . . . 441
Modeling mudcake coupling . . . . . . . . . . . . . . 450
Unchanging mudcake thickness . . . . . . . . . . . . 451
Transient mudcake growth . . . . . . . . . . . . . . 453
General immiscible flow model . . . . . . . . . . . . 457
5.3 Closing Remarks . . . . . . . . . . . . . . . . . . . . . . . . . 458
5.4 References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 464
Cumulative References . . . . . . . . . . . . . . . . . . . . . . . . 467
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 481
About the Authors . . . . . . . . . . . . . . . . . . . . . . . . . . . 498
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