Development and Performance of the Bulalo Geothermal Field

Abstract

The Bulalo Geothermal Field has generated electricity from geothermal steam since 1979. The wells produce two phase fluid from a 260-316 deg C benign, low gas, liquid dominated reservoir which is made up of fractured and intensely altered interlayered volcanics. Separated steam from six satellite stations, flows to NPC's six 55 MW power plants while the residual brine is reinjected back into the reservoir on the periphery of the production area. Through 1988, the reservoir's performance has been excellent. The maximum field-wide steam supply decline rate observed thus far is approximately four percent per year. The power plants, through mid-year 1988, have generated a cumulative total of 15,375 GWh of electricity. The plants are now generating 14 percent of NPC's Luzon grid energy and #re currently the top performing plants in the Philippines.