Preface ................................................. xiii
Nomenclature ............................................ xvii
Chapter 1 Introduction ......................................... 1
1.1 Enhanced Oil Recovery's Potential .......................... 1
1.2 Definitions of EOR and IOR ................................. 1
Existing Definitions ....................................... 2
Proposed Definitions ....................................... 3
1.3 General Description of Chemical EOR Processes .............. 4
1.4 Performance Evaluation of EOR Processes .................... 5
1.5 Screening Criteria for Chemical EOR Processes .............. 8
Formation .................................................. 8
Oil Composition and Oil Viscosity .......................... 8
Formation Water Salinity and Divalents ..................... 8
Reservoir Temperature ...................................... 9
Formation Permeability ..................................... 9
1.6 Naming Conventions and Units ............................... 9
1.7 Organization of This Book ................................. 11
Chapter 2 Transport of Chemicals and Fractional Flow Curve
Analysis ............................................ 13
2.1 Introduction .............................................. 13
2.2 Diffusion ................................................. 13
Diffusion in a Bulk Liquid or Gas Phase ................... 13
Diffusion in a Tortuous Pore .............................. 14
Statistical Representation of Diffusion ................... 15
2.3 Dispersion ................................................ 16
Concept of Dispersion ..................................... 16
Estimate Longitudinal Dispersion Coefficient from
Experimental Data ......................................... 17
Empirical Correlations for the Longitudinal Dispersion
Coefficient ............................................... 22
Empirical Correlations for the Transverse Dispersion
Coefficient ............................................... 24
Evaluation of the Contributions of Diffusion, Convection,
and Dispersion to the Front Spread ........................ 25
Dispersivity .............................................. 26
2.4 Retardation of Chemicals in Single-Phase Flow ............. 28
2.5 Types of Fronts ........................................... 29
Spreading Front ........................................... 31
Indifferent Front ......................................... 31
Sharpening Front .......................................... 32
2.6 Fractional Flow Curve Analysis of Two-Phase Flow .......... 36
Saturation Shock .......................................... 36
Fractional Flow Equation .................................. 37
Retardation of Chemicals in Two-Phase Flow ................ 39
Fractional Flow Curve Analysis of Waterflooding ........... 41
Fractional Flow Curve Analysis of Polymer Flooding ........ 43
Fractional Flow Curve Analysis of Surfactant Flooding ..... 48
Chapter 3 Salinity Effect and Ion Exchange .................... 51
3.1 Introduction .............................................. 51
3.2 Salinity .................................................. 51
3.3 Ion Exchange .............................................. 54
Ion Exchange Equations .................................... 55
Values of Other Exchange Coefficients ..................... 61
Calculation of Exchange Composition ....................... 62
Calculation of Mass Action Constant at Different
Temperatures .............................................. 63
Effect of Diluting an Equilibrium Solution ................ 63
Chromatography ............................................ 64
Effect of pH .............................................. 67
3.4 Low-Salinity Waterflooding in Sandstone Reservoirs ........ 67
Observations of Low-Salinity Waterflooding Effect ......... 68
Proposed Mechanisms ....................................... 68
3.5 Salinity Effect on Waterflooding in Carbonate
Reservoirs ................................................ 73
Wettability Alteration by Seawater Injection into Chalk
Formation ................................................. 74
Chapter 4 Mobility Control Requirement in EOR Processes ....... 79
4.1 Introduction .............................................. 79
4.2 Background ................................................ 79
4.3 Setup of Simulation Model ................................. 82
4.4 Discussion of the Concept of Mobility Control
Requirement ............................................... 84
4.5 Theoretical Investigation ................................. 90
4.6 Numerical Investigation ................................... 93
Effect of Mobility Ratio in a Homogeneous Formation ....... 93
Effect of Mobility Ratio in a Layered Formation ........... 96
Effect of Mobility Ratio in a Heterogeneous Formation ..... 96
4.7 Experimental Justification ................................ 96
4.8 Further Discussion ........................................ 99
Chapter 5 Polymer Flooding ................................... 101
5.1 Introduction ............................................. 101
5.2 Types of Polymers and Polymer-Related Systems ............ 101
Hydrolyzed Polyacrylamide ................................ 102
Xanthan Gum .............................................. 104
Salinity-Tolerant Polyacrylamide—KYPAM ................... 104
Hydrophobically Associating Polymer ...................... 110
2-Acrylamide-2-Methyl Propane-Sulfonate Copolymer ........ 117
Movable Gels ............................................. 119
pH-Sensitive Polymers .................................... 121
BrightWater .............................................. 122
Microball ................................................ 125
Inverse Polymer Emulsion ................................. 127
Preformed Particle Gel ................................... 128
5.3 Properties of Polymer Solutions .......................... 129
Polymer Viscosity ........................................ 129
Polymer Stability ........................................ 135
5.4 Polymer Flow Behavior in Porous Media .................... 148
Polymer Rheology in Porous Media ......................... 148
Polymer Retention ........................................ 153
Inaccessible Pore Volume ................................. 164
Permeability Reduction ................................... 165
Relative Permeabilities in Polymer Flooding .............. 171
5.5 Displacement Mechanisms in Polymer Flooding .............. 176
5.6 Amount of Polymer Injected ............................... 177
5.7 Performance Analysis by Hall Plot ........................ 178
5.8 Polymer Mixing and Well Operations Related Polymer
Injection ................................................ 181
Mixing ................................................... 181
Completion ............................................... 182
Injection Velocity ....................................... 183
Separate Layer Injection ................................. 183
Removing Plugging ........................................ 183
5.9 Special Cases, Pilot Tests, and Field Applications
of Polymer Flooding ...................................... 183
Profile Control by Injection of Polymers with Different
Molecular Weights ........................................ 184
Polymer Injection in Viscous Oil Reservoirs .............. 185
Profile Control in a Strong Bottom and Edge Water
Drive Reservoir .......................................... 188
Offshore Polymer Flooding ................................ 189
Uses of Produced Water ................................... 191
Early Pilot Tests in Daqing .............................. 192
PO and PT Pilot Tests in Daqing .......................... 192
Large-Scale Field Applications ........................... 194
Polymer Flooding Pilot in the Sabei Transition Zone ...... 197
Dagang Gangxi Block 4 PF Pilot with Profile Control ...... 198
Karamay Crosslinked Polymer Solution Pilot ............... 199
Polymer Flooding in a High-Temperature and High-
Salinity Reservoir ....................................... 200
5.10 Polymer Flooding Experience and Learning in China ........ 202
Performance Characteristics during Different Periods ..... 202
Experience and Learning .................................. 202
Chapter 6 Polymer Viscoelastic Behavior and Its Effect on
Field Facilities and Operations .................... 207
6.1 Introduction ............................................. 207
6.2 Viscoelasticity .......................................... 207
6.3 Polymer Viscoelastic Behavior ............................ 212
Shear-Thickening Viscosity ............................... 213
Apparent Viscosity Model for a Full Velocity Range ....... 215
Total Pressure Drop of Viscoelastic Fluids ............... 217
Factors Affecting Polymer Viscoelastic Behavior .......... 218
6.4 Observations of Viscoelastic Effect ...................... 221
Core Flood Observations .................................. 221
Relative Permeability Curves ............................. 225
Secondary and Tertiary Polymer Flooding .................. 226
6.5 Displacement Mechanisms of Viscoelastic Polymers ......... 227
Pulling Mechanism ........................................ 228
Stripping Mechanism ...................................... 229
Mechanism of Oil Thread Flow ............................. 230
Mechanism of Shear-Thickening Effect ..................... 232
6.6 Effect of Polymer Solution Viscoelasticity on Injection
and Production Facilities ................................ 232
Vibration Problem with Flow Lines ........................ 232
Problems with Pump Valves ................................ 234
Problems with Maturation Tanks ........................... 234
Problems with Beam Pumps ................................. 235
Problems with Centrifugal Pumps .......................... 237
Chapter 7 Surfactant Flooding ................................ 239
7.1 Introduction ............................................. 239
7.2 Surfactants .............................................. 239
Types of Surfactants ..................................... 239
Methods to Characterize Surfactants ...................... 240
7.3 Types of Microemulsions .................................. 244
7.4 Phase Behavior Tests ..................................... 247
7.5 Surfactant Phase Behavior of Microemulsions and IFT ...... 254
Ternary Diagrams ......................................... 254
Hand's Rule .............................................. 261
Quantitative Representation of Phase Behavior ............ 268
Effect of Cosolvent (Alcohol) on Phase Behavior .......... 277
Two-Phase Approximation of Phase Behavior without
Type III Environment ..................................... 281
Quantitative Representation of Interfacial Tension ....... 286
Factors Affecting Phase Behavior and IFT ................. 288
7.6 Viscosity of Microemulsion ............................... 291
7.7 Capillary Number ......................................... 293
Definitions: Which One to Use ............................ 293
How to Calculate Capillary Number ........................ 297
7.8 Trapping Number .......................................... 301
7.9 Capillary Desaturation Curve ............................. 307
7.10 Relative Permeabilities in Surfactant Flooding ........... 314
General Discussion of Relative Permeabilities ............ 314
Relative Permeability Models ............................. 315
IFT Effect on the Relative Permeability Ratio krw/krо ..... 319
7.11 Surfactant Retention ..................................... 322
Precipitation ............................................ 322
Adsorption ............................................... 325
Phase Trapping ........................................... 331
7.12 Displacement Mechanisms .................................. 332
Displacement Mechanisms in Dilute Surfactant Flooding .... 332
Displacement Mechanisms in Micellar Flooding ............. 333
7.13 Amount of Surfactant Needed and Process Optimization ..... 334
7.14 An Experimental Study of Surfactant Flooding ............. 334
Chapter 8 Optimum Phase Type and Optimum Salinity Profile
in Surfactant Flooding ............................. 337
8.1 Introduction ............................................. 337
8.2 Literature Review ........................................ 338
Optimum Phase Types ...................................... 338
Optimum Salinity versus Surfactant Concentration ......... 339
Optimum Salinity Gradients ............................... 342
8.3 Sensitivity Study ........................................ 345
Basic Model Parameters ................................... 345
Sensitivity Results ...................................... 345
8.4 Further Discussions ...................................... 360
Effect of kr Curves and Optimum Phase Type ............... 360
Effect of Phase Velocity ................................. 361
Negative Salinity Gradient ............................... 362
8.5 Optimum Phase Type and Optimum Salinity Profile
Concepts ................................................. 365
Optimum Phase Type ....................................... 365
Optimum Salinity Profile ................................. 366
8.6 Summary .................................................. 369
Chapter 9 Surfactant-Polymer Flooding ........................ 371
9.1 Introduction ............................................. 371
9.2 Surfactant-Polymer Competitive Adsorption ................ 371
9.3 Surfactant-Polymer Interaction and Compatibility ......... 372
Observations about Surfactant-Polymer Interaction ........ 372
Factors Affecting Surfactant-Polymer Interaction ......... 374
9.4 Optimization of Surfactant-Polymer Injection Schemes ..... 379
Placement of Polymer ..................................... 379
Effect of the Amounts of Polymer and Surfactant
Injected ................................................. 380
Time to Shift Waterflood to SP ........................... 381
Optimization of the Chemical Flooding Process ............ 383
9.5 A Field Case of SP Flooding .............................. 384
Chapter 10 Alkaline Flooding .................................. 389
10.1 Introduction ............................................. 389
10.2 Comparison of Alkalis Used in Alkaline Flooding .......... 389
General Comparison and pH ................................ 389
Polyphosphate ............................................ 391
Silicate versus Carbonate ................................ 391
Precipitation Problems ................................... 394
10.3 Alkaline Reaction with Crude Oil ......................... 395
In Situ Soap Generation .................................. 396
Emulsification ........................................... 398
Effects of Ionic Strength and pH on IFT .................. 400
10.4 Measurement of Acid Number ............................... 402
10.5 Alkali Interactions with Rock ............................ 405
Alkaline Ion Exchange with Rock .......................... 406
Alkaline Reaction with Rock .............................. 409
Alkali-Water Reactions ................................... 419
Total Alkali Consumption ................................. 420
10.6 Recovery Mechanisms ...................................... 420
A Brief Summary of Mechanisms ............................ 420
IFT Function in Alkaline Flooding ........................ 425
10.7 Simulation of Alkaline Flooding .......................... 427
Mathematical Formulation of Reactions and Equilibria ..... 428
Mathematical Formulation of Alkaline Flooding ............ 430
EQBATCH and UTCHEM ....................................... 432
A Case with Clay and Silica Dissolution/Precipitation
Included ................................................. 455
10.8 Alkaline Concentration and Slug Size in Field Projects ... 456
10.9 Surveillance and Monitoring in Pilot Testing ............. 458
10.10Application Conditions of Alkaline Flooding .............. 458
Chapter 11 Alkaline-Polymer Flooding .......................... 461
11.1 Introduction ............................................. 461
11.2 Interaction between Alkali and Polymer ................... 461
Alkaline Effects on Polymer Viscosity .................... 461
Polymer Effect on Alkaline/Oil IFT ....................... 464
Alkaline Consumption in Alkaline-Polymer Systems ......... 465
11.3 Synergy between Alkali and Polymer ....................... 466
11.4 Field AP Application Example: Liaohe Field ............... 468
Chapter 12 Alkaline-Surfactant Flooding ....................... 473
12.1 Introduction ............................................. 473
12.2 Phase Behavior Tests for the Alkaline-Surfactant
Process .................................................. 473
12.3 Quantitative Representation of Phase Behavior of an
Alkaline-Surfactant System ............................... 474
12.4 Activity Maps ............................................ 477
12.5 Synergy between Alkali and Surfactant .................... 480
12.6 Synergy between Alkali and Surfactant in Heavy Oil
Recovery ................................................. 482
12.7 pH Effect on Surfactant Adsorption ....................... 486
12.8 Recovery Mechanisms ...................................... 492
12.9 Simulation of Phase Behavior of the Alkaline-Surfactant
System ................................................... 492
Setup of Alkaline-Surfactant Batch Model ................. 492
Analysis of Alkaline-Surfactant Phase Behavior ........... 493
Chapter 13 Alkaline-Surfactant-Polymer Flooding ............... 501
13.1 Introduction ............................................. 501
13.2 Synergy of Alkali, Surfactant, and Polymer ............... 501
13.3 Interactions of ASP Fluids and Their Compatibility ....... 501
Alcohol Effect on AS Compatibility ....................... 502
Alkaline and Surfactant Effects in ASP Systems ........... 502
Polymer Effect in ASP Systems ............................ 503
Factors Affecting Phase Separation ....................... 504
Factors Affecting I FT ................................... 506
Factors Affecting Wettability ............................ 508
13.4 Relative Permeabilities in ASP ........................... 509
13.5 Emulsions in ASP Flooding ................................ 510
Types of Emulsions ....................................... 511
Properties of Emulsions .................................. 513
Factors Affecting Emulsion Stability ..................... 518
Effect of Emulsion in Oil Recovery ....................... 521
13.6 Displacement Mechanisms .................................. 521
13.7 Design Optimization of ASP Injection Schemes ............. 522
Effect of Alkali and Surfactant Concentration Gradients ...522
Reduced Surfactant Injection ............................. 522
13.8 Amounts of Chemicals Injected in Field ASP Projects ...... 523
13.9 Vertical Lift Methods in ASP Flooding .................... 526
13.10Problems Associated with ASP ............................. 527
Chromatographic Separation of Alkali, Surfactant,
and Polymer .............................................. 528
Chromatographic Separation of Surfactant Compositions .... 530
Precipitation and Scale Problems ......................... 534
Formation Damage ......................................... 535
Produced Emulsions ....................................... 536
13.11ASP Examples of Field Pilots and Applications ............ 536
Daqing ASP Pilot Test in Sa-Zhong-Xi (S-ZX) .............. 536
Daqing ASP Pilot in Xing-5-Zhong (X5-Z) .................. 540
ASP Pilot in Xing-Er-Xi (X2-X) ........................... 542
Daqing's Largest ASP Application (X2-Z) .................. 545
Daqing ASPF Pilot Test ................................... 549
Shengli Cudong ASP Pilot ................................. 553
Shengli Gudao ASP Pilot .................................. 556
Karamay ASP Pilot ........................................ 558
Jilin Honggang ASP Pilots ................................ 562
Zhongyuan Huzhuangji ASP Pilot ........................... 563
Yumen Laojunmao A/S/P Pilot .............................. 565
References ............................................... 569
Index .................................................... 601
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