| Title | Joint Geophysical Imaging ñ Results and Future Development |
|---|---|
| Authors | P. Malin, E. Shalev & S.A. Onacha |
| Year | 2006 |
| Conference | New Zealand Geothermal Workshop |
| Keywords | |
| Abstract | We have been developing geophysical data collection and analysis methods for the combined use of seismic, electrical resistance, and potential field measurements to guide the drilling of geothermal wells. We call this approach Joint Geophysical Imaging, or JGI. For competitive production of geothermal power, it is essential to develop an JGI well-targeting approach that minimizes drilling. The targeting of even a few 5-10 MW wells for a 70 MW power plant would produce considerable savings. To realize these savings, we propose that the choice of drill sites in geothermal areas be guided by a joint map that couples (not superimposes) seismic, magnetotelluric (MT), and other geophysical measurements such as Time Domain Electromagnetic (TEM), and magnetics and gravity. Our collection methods include borehole sensors, which combine both high temperature seismometers and electrical sensors. The first stage of JGI projects is the collection of an appropriate data. Our previous studies, on which our current Iceland and Hawaii studies are based, were conducted at Coso, Geysers, Long Valley, Olkaria Kenya, and the Parkfield San Andreas Fault. With our Coso data we developed our capacity to do seismic velocity tomography. With our Long Valley data we developed tools for identifying shear-wave splitting. We gained experience at Olkaria with selection of JGI field sites. At Parkfield, we collected our first co-located seismic and MT data sets, in this case using surface explosions for seismic sources. The 3 talks we present at this meeting summarize these and our current Iceland and Hawaii studies. We also propose that a facility to develop both JGI field measuring and analysis techniques be jointly established by a collaborative industry, government, and academia program. |