Geysers Performance Update Through 2006

Abstract

An update on the performance of Calpine’s Geysers steam field from 2003 to 2006 is presented in this paper. Since October 2003, Calpine has received approximately 11 million gallons per day (MGD) of tertiary-treated reclaimed water from the City of Santa Rosa. To accommodate and derive benefit from this water, Calpine has converted 10 wells (5 producers and 5 shut-in wells) to injection service. An additional 8 wells were also converted as low rate injectors that receive 200 gpm (0.3 MGD) or less. Annual recovery factors (i.e. fieldwide increased steam production divided by annual injection) for the first 3 years of SRGRP operation have been estimated at 17.6%, 26.1% and 37.1% respectively, reasonably close to values predicted prior to SRGRP startup. Improvements in the wellfield, water injection and power plant modifications through December 2006 are also updated in this paper. At year-end 2006, Calpine’s 17 operating power plants generated approximately 717 MW net from a steam supply of approximately 13,500 klbm/hr from 336 production wells.