%0 Journal Article
%@ 0375-6505
%A Garcia, Julio
%A Hartline, Craig
%A Walters, Mark
%A Wright, Melinda
%A Rutqvist, Jonny
%A Dobson, Patrick F.
%A Jeanne, Pierre
%A Calpine Corporation, Middletown, CA, USA,
%A Calpine Corporation, Middletown, CA, USA,
%A Calpine Corporation, Middletown, CA, USA,
%A Calpine Corporation, Middletown, CA, USA,
%A Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA, USA,
%A Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA, USA,
%A Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA, USA,
%D 2015
%F epos:1683
%I Elsevier Science
%J Geothermics
%K Enhanced Geothermal Systems; The Geysers; Induced seismicity; Reservoir stimulation; Shear zones
%P 97-119
%T The Northwest Geysers EGS Demonstration Project, California  Part 1: Characterization and reservoir response to injection
%U https://episodesplatform.eu/eprints/1683/
%V 63
%X An Enhanced Geothermal System (EGS) Demonstration Project is currently underway in the Northwest Geysers. The project goal is to demonstrate the feasibility of stimulating a deep high-temperature reservoir (HTR) (up to 400 °C, 750 °F). Two previously abandoned wells, Prati State 31 (PS-31) and Prati 32 (P-32), were reopened and deepened to be used as an injection and production doublet to stimulate the HTR. The deepened portions of both wells have conductive temperature gradients of 10 °F/100 ft (182 °C/km), produce connate native fluids and magmatic gas, and the rocks were isotopically unexchanged by meteoric water. The ambient temperature meteoric water injected into these hot dry rocks has evidently created a permeability volume of several cubic kilometers as determined by seismic monitoring. Preliminary isotopic analyses of the injected and produced water indicate that 50–75% of the steam from the created EGS reservoir is injection-derived.