Geothermal Reservoir Engineering

Foreword

Preface

Acknowledgments


1. Geothermal Reservoirs


1.1 Introduction


1.2 The Development of Geothermal Reservoir Engineering


1.3 Definitions


1.4 The World's Geothermal Resources


1.5 Organization of the Book


1.6 References and Units


2. Conceptual Models of Geothermal Fields and Systems


2.1 Introduction


2.2 Conductive Systems


2.3 Convective Systems: Liquid Dominated


2.4 Convective Systems: Vapor Dominated


2.5 Concepts of Changes under Exploitation


2.6 Developing a Conceptual Model of a Geothermal Reservoir


2.7 Summary


3. Simple Quantitative Models


3.1 Introduction


3.2 Simplifications and Concepts of Storage


3.3 Pressure Transient Models


3.4 Simple Lumped-Parameter Model


3.5 Steam Reservoir with Immobile Water


3.6 Reserves


3.7 Fractured Media


3.8 Chemical Flow Models


3.9 Applicability of the Models


4. Well Completion and Warm-up


4.1 Introduction


4.2 Measurements during Drilling


4.3 The Completed Well


4.4 The Completion Test


4.5 Warm-up


4.6 The "Static" Well


4.7 Vapor-Dominated Systems


4.8 Summary


5. Flow Testing


5.1 Introduction


5.2 Initiating Discharge


5.3 Measurement and Measurement Techniques


5.4 Pressure and Temperature Profiles in Flowing Wells


5.5 Interpretation of Output Data


5.6 Injection


5.7 Summary


6. Case Study: A History of Well BR2, Broadlands Geothermal Field, New Zealand


6.1 Introduction


6.2 The Drilling and Testing Period (May-August 1966)


6.3 The Discharge Period, 1966-1971


6.4 Shutdown and Pressure Recovery August 1971 -December 1980


6.5 Conclusion


7. Quantifying Reservoir Properties


7.1 Introduction


7.2 Inference from Fluid Distribution


7.3 Interference Testing


7.4 Long-Term Reservoir Tests


7.5 Other Tests


7.6 Svartsengi, Iceland


7.7 Raft River


7.8 East Mesa


7.9 Summary


8. Long-Term Behavior: The Observed Response of Fields to Exploitation


8.1 Introduction


8.2 Larderello and Other Italian Fields


8.3 Reykjavik and Selfoss, Iceland


8.4 Wairakei


8.5 The Geysers, California


8.6 Cerro Prieto, Mexico


8.7 Broadlands, New Zealand


8.8 Kawerau


8.9 Ahuachapan


8.10 Summary


9. Field Monitoring and Management


9.1 Introduction


9.2 Measurements


9.3 Changes in Well Performance


9.4 Decline Curves and Trend Analysis


9.5 Sophisticated Reservoir Models


9.6 Optimization


10. Current Geothermal Reservoir Problems


10.1 Introduction


10.2 Fractured Reservoirs, Re-injection, and Tracer Returns


10.3 Surface Activity: Natural and Disturbed


10.4 Subsidence


10.5 Conclusion

Appendix 1. Pressure Transient Analysis

A1.1 Introduction

A1.2 Basic Solution

A1.3 Wellbore Storage and Skin

A1.4 Injection

A1.5 Two-Phase Flow

A1.6 Pseudopressure

A1.7 Variable Flow Rate

A1.8 Fractured Media

A1.9 Wellbore Thermal and Flow Effects

A1.10 Barometric and Tidal Effects; Use of Water Levels

A1.ll Temperature Transients

A1.12 Changes in Permeability

Appendix 2. Equations of Motion and State

A2.1 Introduction

A2.2 Conservation Equations

A2.3 Darcy's Law

A2.4 Constitutive Relations

A2.5 Pressure-Temperature-Depth Relations in Boiling Fluid

Appendix 3. Conversions, Notations, and Properties

A3.1 Steam Tables

A3.2 Notation

A3.3 Unit Conversions

References

Author Index

Subject Index