Performance history of The Geysers steam field, California, USA

Abstract: The performance of Calpine''s Geysers steam field from startup in 1960 to 2008 is described in this paper. Since October 2003, Calpine has received approximately 482L/s of tertiary-treated reclaimed water from the City of Santa Rosa. To accommodate and derive benefit from this water, Calpine has converted 20 wells (ten producers, six shut-in, two observation, and two suspended wells) to high-rate injection service. Additional nine wells were also converted to low-rate injectors that receive 12.6L/s or less. Annual recovery factors (i.e., fieldwide increase in annual steam production divided by annual injection) for the first 5 years of Santa Rosa Geysers Recharge Project (SRGRP) operation have been estimated at 17.6%, 26.1%, 37.1%, 39% and 44.6%, respectively; reasonably close to or slightly higher than the values, predicted prior to SRGRP startup. Using a revised definition that includes the amount of un-boiled water in the reservoir, the annual recovery factors turn out to be 17.6%, 16.1%, 14.6%, 12.4% and 12.2% from year one through year five. Improvements in the wellfield, water injection, and power plant modifications from January 1995 through December 2008 are also discussed in this paper. [Copyright &y& Elsevier]