Chaudhri - Oil Well Testing Handbook

Contents ix

4.4Late Transient Analysis – Bounded (Developed)

Reservoirs ..............................................................

111

4.5Semi-steady-state Analysis – Reservoir Limit

	Test ........................................................................	115
4.6	Two-rate Flow Test Analysis .................................	121
4.7	Variable-rate Flow Tests .......................................	129
4.8	Multi-rate Flow Test Analysis ................................	137
4.9	Drawdown Rate Normalization Methods ..............	146
4.10	Summary ...............................................................	150
References .........................................................................		151
Additional Reading .............................................................		151

5.Pressure Buildup Analysis Techniques for Oil

Wells	.......................................................................	153
5.1	Introduction ............................................................	153
5.2	Ideal Pressure Buildup Test ..................................	153
5.3	Actual Buildup Tests – Infinite Reservoir ..............	156

5.4Pressure Buildup Test Analysis in Infinite-acting

Reservoir ...............................................................

157

5.5Pressure Buildup Testing Methods for Finite

	(Bounded) Reservoir .............................................	176
5.6	Multiphase Buildup Test Analysis .........................	194
5.7	Afterflow Analysis Using Russel’s Technique .......	199

5.8Pressure Buildup Tests Preceded by Two

	Different Flow Rates ..............................................	201
5.9	Variable-rate Pressure Buildup Analysis ...............	206
5.10	Multi-phase, Multi-rate Buildup Analysis ...............	210

5.11Rate Normalization Techniques and Procedures

(Pressure Buildup Data) ........................................	214
5.12 Summary ...............................................................	231
References and Additional Reading ..................................	232

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x Contents

6.Original and Average Reservoir Pressure

Estimation Methods ..............................................	234
6.1 Introduction ............................................................	234

6.2Original Reservoir Pressure in Infinite

Reservoirs ..............................................................

234

6.3Estimating Average and Initial Reservoir

Pressure ................................................................

235

6.4Estimating Constant Pressure at Aquifer in

	Water-drive Reservoirs ..........................................	244
6.5	Summary ...............................................................	252
References and Additional Reading ..................................		252

7.Well Testing Methods for Naturally Fractured

Reservoirs ..............................................................		254
7.1	Introduction ............................................................	254
7.2	Identification of Natural Fractures .........................	254

7.3Characteristics of Naturally Fractured

Reservoirs ..............................................................

255

7.4Typical Pressure Drawdown Behavior Curve

	Shapes ...................................................................	255
7.5	Pressure Buildup Behavior Characteristics ..........	256

7.6Well Test Interpretation Methods, Uses, and

Limitations ..............................................................

257

7.7Buildup Analysis Techniques for Tight Reservoir

Matrix .....................................................................

270

7.8Interpretation of Interference Tests in Matrix and

Fractured Reservoirs .............................................

275

7.9Horizontal Well Pressure Behavior Curve

Shapes ...................................................................

278

7.10Horizontal Well Production Forecasting – Dual-

porosity Reservoir ..................................................

284

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Contents	xi
7.11 Summary ...............................................................	285
References and Additional Reading ..................................	285

8.Fundamentals of Type Curve Matching

Methods for Oil Wells ............................................		287
8.1	Introduction ............................................................	287
8.2	Application to Conventional Tests .........................	287
8.3	Fracture Type Curve Matching Techniques ..........	313
8.4	Type Curves – Horizontal Fractured Oil Wells ......	329
8.5	Summary ...............................................................	337
References and Additional Reading ..................................		338

9.Flow Regime Identification and Analysis Using

Special Methods ....................................................		339
9.1	Introduction ............................................................	339
9.2	Fracture Linear Flow Period ..................................	339
9.3	Bilinear Flow ..........................................................	341
9.4	Formation Linear Flow ...........................................	345
9.5	Pseudo-radial Flow ................................................	346
9.6	Type Curve Matching Methods .............................	346
9.7	Summary ...............................................................	356
References .........................................................................		357
Additional Reading .............................................................		357
10. Application of Pressure Derivative in Oil Well
Test Analysis .........................................................		359
10.1	Introduction ............................................................	359

10.2Pressure Derivative Applications in Well Test

	Analysis ..................................................................	359
10.3	Pressure Derivative Analysis Methods .................	359
10.4	Fractured Reservoir Systems ................................	365

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xiiContents

10.5Pressure Derivative Trends for Other Common

	Flow Regimes ........................................................	370
10.6	Summary ...............................................................	371
References .........................................................................		371
Additional Reading .............................................................		371
11. Massive Hydraulic-fractured Oil Well Behavior
Analysis ..................................................................		372
11.1	Introduction ............................................................	372
11.2	Methods of Evaluating MHF Oil Wells ..................	372
11.3	Analyzing Infinite Flow Capacity Fractures ...........	372
11.4	Analyzing Finite Flow Capacity Fractures .............	373

11.5Estimating Formation Characteristics of Finite

Conductivity Fractures ...........................................

378

11.6Pretreatment Testing of Hydraulically Fractured

	Candidate ..............................................................	384
11.7	Summary ...............................................................	385
References .........................................................................		386
Additional Reading .............................................................		386
12. Drill-stem Testing Methods ..................................		387
12.1	Introduction ............................................................	387
12.2	DST Equipment and Operational Procedures ......	388

12.3Recommended Flow and Shut-in Time for Drill-

stem Tests .............................................................	389
12.4 Troubleshooting DST Pressure Charts .................	390

12.5Checking Validity and Consistency of Reporting

DST Data ...............................................................	391
12.6 Estimation of Average Flow Rate ..........................	392

12.7DST Analysis Methods, Uses, and Limitations ..... 396

12.8 Wireline Formation Test Data Evaluation .............

414

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	Contents	xiii
12.9	Summary ...............................................................	427
References and Additional Reading ..................................		427
13. Interference and Pulse Test Analysis Methods ....		429
13.1	Introduction ............................................................	429
13.2	Interference Test Analysis Techniques .................	429
13.3	Analysis of Pulse Test Pressure Response ..........	434

13.4Vertical Pulse Test Design and Analysis

	Methods .................................................................	445
13.5	Design and Analysis of Unequal Pulses ...............	448
13.6	Summary ...............................................................	462
References .........................................................................		462
Additional Reading .............................................................		462
14. Injection Well Transient Testing and Analysis		... 463
14.1	Introduction ............................................................	463
14.2	Injectivity Test Analysis Methods ..........................	463
14.3	Pressure Fall-off Test Analysis Methods ..............	475
14.4	Two-rate Injectivity Test Analysis ..........................	492
14.5	Step-rate Injectivity Testing Technique .................	496
14.6	Summary ...............................................................	502
References .........................................................................		502
Additional Reading .............................................................		503
15. Well Testing Methods in Multilayered Oil
Reservoir Systems ................................................		504
15.1	Introduction ............................................................	504

15.2Identification of Layered Oil Reservoir Systems ... 504

15.3Analyzing Pressure Behavior in Multilayered

Systems .................................................................

505

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xivContents

15.4Concept of Reservoir Layer Fracture

Conductivity ...........................................................

509

15.5Pressure Production Performance Response

Equations ...............................................................

510

15.6Investigating Degree of Communication and

Type of Crossflow ..................................................

512

15.7Pressure Buildup Characteristics in Layered

Reservoir Systems ................................................

512

15.8Pressure Analysis Methods for Oil Wells

Producing Commingled Zones ..............................

514

15.9Factors Affecting Multilayered Reservoir

	Performance ..........................................................	520
15.10	Economic Aspects of Interlayer Crossflow ............	521
15.11	Summary ...............................................................	521
References and Additional Reading ..................................		521
16. Pressure Analysis Methods in Heterogeneous
Oil Reservoir Systems ..........................................		523
16.1	Introduction ............................................................	523
16.2	Effect of Pressure on Rock Properties ..................	523
16.3	Major Causes of Heterogeneities ..........................	524

16.4Pressure Responses near No Flow Boundaries ... 524

16.5Effect of Hydraulic Diffusivity on Reservoir

Behavior .................................................................

534

16.6Simple Procedures and Guidelines to Estimate

Reservoir Heterogeneity Properties ......................

536

16.7General Approach to Estimate Fracture Trends

or Heterogeneity ....................................................

536

16.8Determination of Reservoir Parameters and

Fracture Orientations .............................................

536

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Contents xv

16.9Defining Reservoir Heterogeneity by Multiple-

well Tests ...............................................................		539
16.10 Method for Calculating Fracture Orientation .........		555
16.11 Estimating Two-dimensional Permeability with
Vertical Interference Testing .................................		556
16.12 Application of Pulse Tests to Describe Reservoir
Heterogeneity ........................................................		561
16.13 Validity of Various Models and Steps Used to
Obtain Reservoir Description ................................		573
16.14 Summary ...............................................................		574
References and Additional Reading ..................................		574
Appendices
Appendix A: Conversion Factors between Unit Systems ........		577
Appendix B: Correlation Tables and Dimensionless
Functions ..............................................................		585
References and Additional Reading ................		594
Appendix C: Pressure Drop through Vertical, Inclined, and
Horizontal Oil Wells ..............................................		595
C.1	Hagedorn and Brown Method .................	596
C.2	Beggs and Brill Method ...........................	602
References and Additional Reading ................		606
Appendix D: Oil and Water PVT Properties and Correlation
Equations .............................................................		607
D.1	Oil PVT Properties and Correlations .......	608
D.2	Solution Gas-oil Ratio .............................	612
D.3	Oil Formation Volume Factor ..................	613
D.4	Total Formation Volume Factor ...............	616
D.5	Oil Density ..............................................	616
D.6	Oil Viscosity ............................................	618
D.7	Oil Compressibility ..................................	622

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xvi Contents
D.8 Reservoir Rock Properties ......................	623
D.9 Reservoir PVT Water Properties .............	624
References and Additional Reading ................	639
Nomenclature ................................................................	640
Bibliography ..................................................................	645
Index ...............................................................................	661

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