Page 11 - Geothermal Energy Systems Exploration, Development, and Utilization

Contents IX

3.11.1.1 Topdrive 166
3.11.1.2 Rotary Steerable Systems (RSS) 166
3.11.1.3 Multilateral Wells 169
3.11.2 Other R&D-Themes of high Interest 169
References 170

4 Enhancing Geothermal Reservoirs 173
Thomas Schulte, G¨unter Zimmermann, Francois Vuataz, Sandrine
Portier, Torsten Tischner, Ralf Junker, Reiner Jatho, and Ernst Huenges
4.1 Introduction 173
4.1.1 Hydraulic Stimulation 174
4.1.2 Thermal Stimulation 174
4.1.3 Chemical Stimulation 174
4.2 Initial Situation at the Specific Location 174
4.2.1 Typical Geological Settings 174
4.2.2 Appropriate Stimulation Method According to Geological System
and Objective 175
4.3 Stimulation and Well path Design 176
4.4 Investigations Ahead of Stimulation 178
4.5 Definition and Description of Methods (Theoretical) 180
4.5.1 Hydraulic Stimulation 180
4.5.1.1 General 180
4.5.1.2 Waterfrac Treatments 181
4.5.1.3 Gel-Proppant Treatments 182
4.5.1.4 Hybrid Frac Treatments 183
4.5.2 Thermal Stimulation 183
4.5.3 Chemical Stimulation 184
4.6 Application (Practical) 187
4.6.1 Hydraulic Stimulation 187
4.6.1.1 Induced Seismicity 189
4.6.2 Thermal Stimulation 193
4.6.3 Chemical Stimulation 194
4.7 Verification of Treatment Success 197
4.7.1 General 197
4.7.1.1 Wireline Based Evaluation 197
4.7.1.2 Hydraulic Well Tests 197
4.7.1.3 Tracer Testing 198
4.7.1.4 Monitoring Techniques 200
4.7.2 Evaluation of Chemical Stimulations 201
4.8 Outcome 202
4.8.1 Hydraulic Stimulation 202
4.8.1.1 Hydraulic Stimulation – Soultz 202
4.8.1.2 Hydraulic Stimulation Groß Sch¨ onebeck 203
4.8.2 Thermal Stimulation 204
4.8.3 Chemical Stimulation 204