Geothermal Energy Systems......Page 5
Contents......Page 7
Preface......Page 17
List of Contributors......Page 21
1.1.1 Introduction to Earth’s Heat and Geothermics......Page 25
1.1.2 Cooling of the Core, Radiogenic Heat Production, and Mantle Cooling......Page 26
1.1.3.1 Mantle Heat Flow Variations......Page 28
1.1.3.2 Subcontinental Thermal Boundary Condition......Page 29
1.1.4 Fourier’ Law and Crustal Geotherms......Page 30
1.1.5.1 Steady-state Heat Refraction......Page 32
1.1.5.3 Role of Anisotropy of Thermal Conductivity......Page 34
1.1.6 Fluid Circulation and Associated Thermal Anomalies......Page 36
1.2 Heat Flow and Deep Temperatures in Europe......Page 37
1.2.1 Far-field Conditions......Page 38
1.2.2 Thermal Conductivity, Temperature Gradient, and Heat Flow Density in Europe......Page 41
1.2.3 Calculating Extrapolated Temperature at Depth......Page 42
1.2.4 Summary......Page 44
1.3 Conceptual Models of Geothermal Reservoirs......Page 45
1.3.1 The Geology of Potential Heat Sources......Page 46
1.3.2 Porosity, Permeability, and Fluid Flow in Relation to the Stress Field......Page 51
1.3.3 Summary......Page 54
References......Page 56
2.1 Introduction......Page 61
2.2 Geological Characterization......Page 63
2.3 Relevance of the Stress Field for EGS......Page 68
2.4 Geophysics......Page 76
2.4.1 Electrical Methods (DC, EM, MT)......Page 77
2.4.1.1 Direct Current (DC) Methods......Page 78
2.4.1.3 The Magnetotelluric Method......Page 79
2.4.1.4 Active Electromagnetic Methods......Page 87
2.4.2 Seismic Methods......Page 90
2.4.2.1 Active Seismic Sources......Page 91
2.4.2.2 Seismic Anisotropy and Fractures......Page 95
2.4.2.3 Passive Seismic Methods......Page 97
2.4.3.1 Gravity......Page 100
2.4.3.2 Geomagnetics and Airborne Magnetic......Page 102
2.4.4 Data Integration......Page 104
2.5.1 Introduction......Page 105
2.5.2 Fluids and Minerals as Indicators of Deep Circulation and Reservoirs......Page 107
2.5.3 Mud and Fluid Logging while Drilling......Page 109
2.5.4 Hydrothermal Reactions......Page 110
2.5.4.1 Boiling and Mixing......Page 112
2.5.5 Chemical Characteristics of Fluids......Page 115
2.5.5.2 Acid–Sulfate Waters......Page 116
2.5.5.4 Acid Chloride–Sulfate Waters......Page 117
2.5.6 Isotopic Characteristics of Fluids......Page 118
2.5.7 Estimation of Reservoir Temperature......Page 121
2.5.7.2 Silica Geothermometer......Page 122
2.5.7.3 Ionic Solutes Geothermometers......Page 123
2.5.8 Forecast of Corrosion and Scaling Processes......Page 124
References......Page 127
Further Reading......Page 135
3.1 Introduction......Page 137
3.1.1 Geothermal Environments and General Tasks......Page 138
3.2.1.2 Top Drive or Rotary Table......Page 139
3.2.1.3 Mud Pumps......Page 140
3.2.2.1 Bottomhole Assembly......Page 142
3.2.2.2 Drillpipe......Page 145
3.2.3.2 Rotary Steerable Systems (RSS)......Page 146
3.2.3.5 Special Computer Program to Evaluate Where the Bottom of the Hole Is at Survey Depth......Page 147
3.3 Drilling Mud......Page 149
3.3.1.4 Air......Page 150
3.3.2.2 Formation Pressure and Formation Damage (Hydrostatic Head, ECD)......Page 151
3.4 Casing and Cementation......Page 152
3.4.2 Casing Materials......Page 153
3.4.3 Pipe Centralization......Page 155
3.4.4 Cementation......Page 156
3.4.5 Cement Slurries, ECD......Page 157
3.5.1 Geological Forecast......Page 160
3.5.1.2 Pore Pressures/Fracture Pressure/Temperature......Page 161
3.5.1.5 Permeabilities......Page 162
3.5.2.3 Casing Sizes......Page 163
3.5.2.4 Casing String Design......Page 164
3.6.1.1 Turnkey Contract......Page 166
3.6.1.4 Incentive Contract......Page 167
3.6.3 Drilling Operations......Page 168
3.6.4 Problems and Trouble Shooting......Page 169
3.7.1.2 Pretensioning......Page 172
3.7.2 Wellheads, Valves and so on......Page 174
3.7.3 Well Completion without Pumps with Naturally Flowing Wells......Page 175
3.8 Risks......Page 176
3.8.1.2 Poor Well Design......Page 177
3.8.2.2 Failure of Subsurface Equipment......Page 178
3.8.3 Geological–Technical Risks......Page 179
3.8.4 Geological Risks......Page 181
3.9 Case Study Groß Schonebeck Well......Page 183
3.10 Economics (Drilling Concepts)......Page 186
3.10.1.1 Casing Scheme......Page 188
3.11.1 Technical Trends......Page 189
3.11.1.2 Rotary Steerable Systems (RSS)......Page 190
3.11.2 Other R&D-Themes of high Interest......Page 193
References......Page 194
4.1 Introduction......Page 197
4.2.1 Typical Geological Settings......Page 198
4.2.2 Appropriate Stimulation Method According to Geological System and Objective......Page 199
4.3 Stimulation and Well path Design......Page 200
4.4 Investigations Ahead of Stimulation......Page 202
4.5.1.1 General......Page 204
4.5.1.2 Waterfrac Treatments......Page 205
4.5.1.3 Gel-Proppant Treatments......Page 206
4.5.2 Thermal Stimulation......Page 207
4.5.3 Chemical Stimulation......Page 208
4.6.1 Hydraulic Stimulation......Page 211
4.6.1.1 Induced Seismicity......Page 213
4.6.2 Thermal Stimulation......Page 217
4.6.3 Chemical Stimulation......Page 218
4.7.1.2 Hydraulic Well Tests......Page 221
4.7.1.3 Tracer Testing......Page 222
4.7.1.4 Monitoring Techniques......Page 224
4.7.2 Evaluation of Chemical Stimulations......Page 225
4.8.1.1 Hydraulic Stimulation – Soultz......Page 226
4.8.1.2 Hydraulic Stimulation Groß Schonebeck......Page 227
4.8.3 Chemical Stimulation......Page 228
4.9.1.1 Proppant Selection......Page 230
4.9.2 Thermal Stimulation......Page 233
4.10.1.1 Introduction......Page 234
4.10.1.3 Hydraulic Fracturing in Sandstones (Gel-Proppant Stimulation)......Page 235
4.10.1.4 Hydraulic fracturing in Volcanics (Waterfrac Stimulation)......Page 236
4.10.1.5 Hydraulic Fracturing Treatments in GrSk4/05......Page 237
4.10.1.6 Hydraulic Fracturing Treatment in Volcanics (Waterfrac Stimulation)......Page 238
4.10.1.7 Hydraulic Fracturing in Sandstones (Gel-Proppant Stimulation)......Page 239
4.10.1.8 Conclusions......Page 240
4.10.2.1 Hydraulic Stimulation......Page 241
4.10.2.2 Chemical Stimulation......Page 247
4.10.3.1 Introduction......Page 250
4.10.3.2 Fracturing Experiments......Page 252
4.10.3.3 Summary and Conclusion......Page 256
References......Page 257
Further Reading......Page 264
5.1 Introduction......Page 269
5.1.1 Geothermal Modeling......Page 270
5.1.2 Uncertainty Analysis......Page 271
5.2.2 THM Mechanics......Page 272
5.2.2.1 Heat Transport......Page 273
5.3 Reservoir Characterization......Page 274
5.3.1.2 Poroperm Relationships......Page 275
5.3.2.1 Density and Viscosity......Page 278
5.3.2.2 Heat Capacity and Thermal Conductivity......Page 279
5.3.3 Supercritical Fluids......Page 281
5.3.4 Uncertainty Assessment......Page 282
5.5.1 Introduction......Page 284
5.5.2.1 Geology......Page 285
5.5.2.2 Structure......Page 286
5.5.2.4 Hydraulic Conditions......Page 287
5.5.3 Modeling Approach......Page 288
5.5.4 Results......Page 289
5.6.1.1 Conceptual Model......Page 292
5.6.1.3 Stimulated Reservoir Model......Page 294
5.6.1.4 Monte Carlo Analysis......Page 295
5.6.2.1 Conceptual Model......Page 299
5.6.2.2 Development of Preferential Flow Paths due to Positive Feedback Loops in Coupled Processes and Potential Reservoir Damage......Page 300
5.6.3 The Importance of Thermal Stress in the Rock Mass......Page 302
5.7 Rosemanowes (United Kingdom)......Page 303
5.8 Soultz-sous-Forets (France)......Page 304
5.9.1 Introduction......Page 308
5.9.2 Geomechanical Facies and Modeling the HM Behavior of the KTB Pump Test......Page 309
5.10 Stralsund (Germany)......Page 311
5.10.2 Model Setup......Page 314
5.10.3 Long-Term Development of Reservoir Properties......Page 315
References......Page 317
6.1.1 Energetic Considerations......Page 327
6.1.2 Heat Provision......Page 330
6.1.3 Chill Provision......Page 332
6.1.4 Power Provision......Page 336
6.2.1 Geothermal Fluid Loop......Page 340
6.2.1.1 Fluid Properties......Page 341
6.2.1.2 Operational Reliability Aspects......Page 347
6.2.1.3 Fluid Production Technology......Page 353
6.2.2 Heat Exchanger......Page 356
6.2.2.1 Heat Exchanger Analysis – General Considerations......Page 357
6.2.2.2 Selection of Heat Exchangers......Page 359
6.2.2.3 Specific Issues Related to Geothermal Energy......Page 361
6.2.3 Direct Heat Use......Page 362
6.2.4 Binary Power Conversion......Page 365
6.2.4.1 General Cycle Design......Page 366
6.2.4.2 Working Fluid......Page 371
6.2.4.3 Recooling Systems......Page 376
6.2.5.1 Cogeneration......Page 383
6.2.5.2 Serial Connection......Page 384
6.2.5.3 Parallel Connection......Page 385
6.3 Case Studies......Page 386
6.3.1.2 Design Approach......Page 387
6.3.1.3 Gross Power versus Net Power Maximization......Page 388
6.3.2.1 Objective......Page 390
6.3.2.3 Serial versus Parallel Connection......Page 391
References......Page 392
7.1 Introduction......Page 397
7.2.1 Levelized Cost of Energy (LCOE)......Page 399
7.2.1.1 Methodological Approach......Page 400
7.2.1.2 Cost Analysis......Page 401
7.2.1.3 Case Studies......Page 407
7.2.2 Decision and Risk Analysis......Page 417
7.2.2.1 Methodology......Page 418
7.2.2.2 Case Study......Page 421
7.3 Impacts on the Environment......Page 429
7.3.1.1 Methodological Approach......Page 430
7.3.1.2 Case Studies......Page 432
7.3.2.1 Local Impacts......Page 436
7.3.2.2 Environmental Impact Assessment......Page 441
References......Page 443
8.2 CO2 Emission by Electricity Generation from Different Energy Sources......Page 447
8.3 Costs of Mitigation of CO2 Emissions......Page 448
8.5.1 Technological Factors......Page 450
8.5.2 Economic and Political Factors......Page 451
References......Page 452
Color Plates......Page 453
Index......Page 469