Reservoir Engineering in Modern Oilfields

Real-world reservoirs are layered, heterogeneous and anisotropic, exposed to water and gas drives, faults, barriers and fractures. They are produced by systems of vertical, deviated, horizontal and multilateral wells whose locations, sizes, shapes and topologies are dictated "on the fly, at random"by petroleum engineers and drillers at well sites. Wells may be pressure or rate-constrained, with these roles re-assigned during simulation with older laterals shut-in, newer wells drilled and brought on stream, and so on. And all are subject to steady and transient production, each satisfying different physical and mathematical laws, making reservoir simulation an art difficult to master and introducing numerous barriers to entry. All of these important processes can now be simulated in any order using rapid, stable and accurate computational models developed over two decades. And what if it were further possible to sketch complicated geologies and lithologies, plus equally complex systems of general wells, layer-by-layer using Windows Notepad? And with no prior reservoir simulation experience and only passing exposure to reservoir engineering principles? Have the user press "Simulate," and literally, within minutes, produce complicated field-wide results, production forecasts, and detailed three-dimensional color pressure plots from integrated graphics algorithms? Developed over years of research, this possibility has become reality. The author, an M.I.T. trained scientist who has authored fifteen original research books, over a hundred papers and forty patents, winner of a prestigious British Petroleum Chairman's Innovation Award in reservoir engineering and a record five awards from the United States Department of Energy, has delivered just such a product, making real-time planning at the well-site simple and practical. Workflows developed from experience as a practicing reservoir engineer are incorporated into "intelligent menus" that make in-depth understanding of simulation principles and readings of user manuals unnecessary. This volume describes new technology for down-to-earth problems using numerous examples performed with our state-of-the-art simulator, one that is available separately at affordable cost and requiring only simple Intel Core i5 computers without specialized graphics boards. The new methods are rigorous, validated and well-documented and are now available for broad petroleum industry application.

Autorentext

Wilson C. Chin earned his Ph.D. from M.I.T. and his M.Sc. from Caltech. He has published fifteen books describing his original research in reservoir engineering, formation testing, managed pressure drilling, wave propagation, Measurement While Drilling (MWD) and electromagnetic well logging, over one hundred papers and three dozen patents. Mr. Chin has consulted for well known domestic and international oil and gas corporations, and during the past two decades, won five prestigious research contracts and awards in petroleum exploration and production with the United States Department of Energy.

Inhalt

Preface ix

Acknowledgements xiii

1 Reservoir Modeling Background and Overview 1

Overview 1

Reservoir modeling landscape 1

Reflections on simulation and modeling 2

Reservoir Flow Algorithms for Petroleum Engineers 3

Multisim™ Features Advanced Interactive

Reservoir Modeling 8

Reservoir description 9

Well system modeling 9

Additional simulator features 9

Simple Wells to Multilateral Systems for Laymen 10

Advanced Graphics for Color Display 17

Tracer Movement in Three-Dimensional Reservoirs 21

2 Mathematical Modeling Ideas, Numerical Methods and Software 25

Overview and Background 25

Formulation errors 25

I/O problems 26

Fundamental Issues and Problems 26

Numerical stability 27

Inadequacies of the von Neumann test 28

Convergence 28

Physical resolution 29

Direct solvers 29

Modern simulation requirements 30

Pressure constraints 32

Flow rate constraints 32

Object-oriented geobodies 33

Plan for remaining sections 33

Governing Equations and Numerical Formulation 33

Steady flows of liquids 33

Difference equation formulation 34

The iterative scheme 35

Modeling well constraints for liquids 36

Steady and unsteady nonlinear gas flows 38

Steady gas flows 39

Well constraints for gas flows 40

Transient, compressible flows 42

Compaction, consolidation and subsidence 44

Boundary conforming grids 45

Stratigraphic meshes for layered media 46

Modeling wellbore storage 47

Early 1990s Validation Calculations 48

Simulation capabilities 48

Data structures and programming 49

Example 2-1. Convergence acceleration, two deviated horizontal gas wells in a channel sand 49

Example 2-2. Dual-lateral horizontal completion in a fractured, dipping, heterogeneous, layered formation 53

Example 2-3. Stratigraphic grids, drilling dome-shaped structures 56

Example 2-4. Simulating-while-drilling horizontal gas wells through a dome-shaped reservoir 58

Example 2-5. Modeling wellbore storage effects and compressible borehole flow transients 64

3 Simulation Capabilities User Interface with Basic Well 71

Example 3-1. Single vertical well, user interface and menu structure for steady flow 71

Example 3-2. Volume flow rate constraint at a well 91

Example 3-3. Pressure constraint and transient shut-in 94

Example 3-4. Heterogeneities, anisotropy and multiple wells 110

Example 3-5. Reversing well constraints consistency check 128

Example 3-6. Changing farfield boundary conditions 131

Example 3-7. Fluid depletion in a sealed reservoir 135

Example 3-8. Depletion in rate constrained well in sealed reservoir 147

Example 3-9. Steady flow from five spot pattern 148

Example 3-10. Drilling additional wells while simulating 153

4 Vertical, Deviated, Horizontal and Multilateral Well Systems 175

Overview, 175

Example 4-1. Multilateral and vertical wells in multilayer media 176

Example 4-2. Dual lateral with transient operations 204

Example 4-3. Producer and injector conversions 239

Example 4-4. Production with top and bottom drives 265

Example 4-5. Transient gas production from dual horizontal with wellbore storage effects 275

5 Well Models and Productivity Indexes 290

Radial vs 3D modeling - loss of wellbore resolution 290

Analogies in computational aerodynamics 291

Curvilinear grids in reservoir simulation 293

Productivity index modeling 295

References 296

Index 308

About the Author 312

Professional interests 312

Scientific book publications 313

United States patents 314 &l...