Reservoir Confirmation of the Buckeye Power Plant Area: Wildhorse State 36 Confirmation Well, Northwest Geysers - Final Project Report

Cover of report

Reservoir Confirmation of the Buckeye Power Plant Area: Wildhorse State 36 Confirmation Well, Northwest Geysers - Final Project Report. (PDF file, 75 pages, 2.6 megabytes).

Appendices


Publication Number: CEC-500-2013-076
Report Date: March 2011

 


Abstract

The Wildhorse State 36 well was drilled as one of three wells needed to confirm financing of a proposed new 33 megawatt Buckeye Power Plant in the northwest area of The Geysers geothermal field in Sonoma County, California. The project was co-funded by the California Energy Commission. Wildhorse State 36 was drilled, completed and tested between October 2009 and December 2010. The well was drilled to a depth of 12,340 feet at a cost of about $7.5 million.

A resource was found but proved insufficient to justify constructing a new generator in the Buckeye Power Plant area. The power density estimated in previous studies and the hypothesis that the Buckeye area exists in a separate structural zone or “compartment” isolating it from nearby areas were not confirmed. Testing results showed that the Wildhorse State 36 well may have the capacity to produce less than 1.5 megawatts of equivalent steam. This does not justify investing in the new deep wells that would be needed to support construction of a new generator. Wildhorse State 36 was completed as an injector well but cannot serve as an injector in an enhanced geothermal system because it was drilled through a deep high temperature reservoir into a lower temperature zone. Steam from the well could be collected and piped to existing power plants. The geochemical, temperature, rock type, geologic structure, and isotope data gained from the tests and analyses on this well and other nearby wells will be valuable in planning future exploration in the northern part of The Geysers.