creation of an enhanced geothermal system through hydraulic and thermal stimulation de-fc07-01id14186

1. Peter Rose, Principal Investigator Energy and Geoscience Institute at the University of Utah Geothermal Program Briefing Lawrence Berkeley National Laboratory March 16, 2004

3. The East Flank of the Coso Geothermal Reservoir is an Excellent Setting for an Enhanced Geothermal System due to: High reservoir temperatures Often exceeding 300oC at less than 10,000 ft A high degree of fracturing Many fractures are optimally orientated for shear failure Existing reservoir stresses are close to critical Good candidate wells for testing of stimulation techniques 83-16 34A-9 34-9RD2 EGS R&D objectives that run parallel to COC�s reservoir- management (injection) needs

4. The Coso Project

5. The CosoEast Flank EGS Study Area

6. The Coso EGS Injector/Producer Well Pair

7. The Coso/EGS Team

8. Coso/EGS Project Objectives To design, create and evaluate an Engineered Geothermal System within the margins of the Coso geothermal field To demonstrate an increased electrical production of 10 MWe upon the creation of the Coso EGS

9. Fracture/Stress Analysis Judith Sheridan, GMI; Steve Hickman, USGS Objectives: Develop a full stress tensor of the candidate EGS reservoir Predict proximity to shear failure by characterizing wellbore fracturing through electrical or ultrasonic image logs

10. Petrophysics Terratek Objective: Measure the compressive and tensile strength, thermal properties, resistivity, and acoustic velocity of representative Coso EGS cores

11. Petrology and Petrograpy Joe Moore and Katie Kovac, EGI Objectives: Characterize core and cuttings in order to understand the fabric of the candidate EGS reservoir Develop an empirical model to relate rock type and alteration mineralogy to shear failure resulting from hydraulic stimulation

12. Fluid-Flow Modeling Dan Swenson and students, KSU; Paul Spielman, COC; Christian Kasteler, EGI Objectives Perform coupled thermal-hydraulic-mechanical analyses�that enable quantitative understanding and prediction of thermal effects on flow in the Coso reservoir.� Identify the conditions under which thermal stimulation is significant and predict the magnitude of the change resulting from such stimulation

13. Geochemical Modeling Mike Adams, EGI Objectives: Develop realistic methods of calculating geochemical interactions that influence the permeability between an injection and a production well Calculate scale potential for various candidate mixing fractions

14. Magnetotellurics Phil Wannamaker, EGI Objectives: Determine the resistivity structure of the Coso EGS study area Determine the feasibility of using MT to characterize hydraulic stimulation effects in real time

15. Microseismic Monitoring and Analysis Frank Monastero, Navy GPO; Gillian Foulger, Bruce Julian, USGS; Stefan Baisch, Q-con Objectives: Develop and demonstrate methods for the real-time microseismic hypocenter location of earthquakes accompanying an east-flank hydraulic stimulation Develop and demonstrate methods for the near-real-time determination of moment-tensor source mechanisms

16. 3-D Visualization Doug Ekart, EGI Objective: Using a customized Matlab code, develop and implement a program for visualizing EGS data in 3-D

17. 34-9RD2 Stimulation Experiment Objective: to hydraulically stimulate a formation volume adjacent to 34-9RD2, achieving an injection rate of 750 gpm at 100 psi wellhead pressure while developing hydraulic communication with surrounding wells

18. 34-9RD2 Stimulation Experiment Approach: Prepare hole by replacing 7� liner and cementing to surface. Drill 500 feet of open-hole (7600�-8100�), removing cuttings at 2� intervals and 2 core barrels of spot core. Conduct PTS, borehole televiewer, gamma-ray, density, neutron, induction, and EMI logs in open hole section. Perform rig injection test. Trip out, release rig, and deploy pumps and tanks for hydraulic stimulation experiment Conduct hydraulic stimulation experiment Long-duration injection, maintaining pore pressure below minimum horizontal stress Continuous near-real-time microseismic monitoring using GPO�s permanent and portable arrays Continuous MT monitoring Continuous tracer tagging of stimulation fluids and intermittent monitoring of surrounding wells

19. 34-9RD2 Schedule

20. EGS Challenges Geomechanics Characterizing the tectonic setting Matching the stimulation approach to the tectonic setting Understanding the effect of rock/vein type on self-propping mechanisms Geochemistry Predicting the effect of injection-water chemistry on dissolution/precipitation in the wellbore and in the formation Development of chemical stimulants for maintaining and/or enhancing fracture permeabilities Development of tracers and tracer technologies for characterizing formation geometries and fluid-flow processes Geophysics Developing and demonstrating microseismic and electromagnetic methods for characterizing hydraulic stimulation processes Fluid-Flow Modeling Developing and demonstrating a code for predicting the effects of hydraulic stimulation on fracture permeability