Changes in the Apparent Piezometric Levels in the Palinpinon Field as a Response to Twelve Years of Exploitation

Abstract

Field pressure reduction in the Puhagan sector of the Palinpinon Geothermal Field resulted in the depression of the apparent piezometric levels. Drawdown of between 20-300 m centered in Puhagan IYQS observed since the start of power generation in June, 1983 and until October, 1989. Further drawdown of as much as 50 to 520 m was observed centered in Puhagan between 1989 and 1993 as a result of increased mass withdrawal due to the connection of Panay Island to the Negros Power Grid in October, 1990. This drawdown in Puhagan has reversed the hydrostatic head between the production and reinjection sectors. This head reversal, along with the permeability of the fault connections and the proximity between the two sectors may enhance the amount and rate at which reinjection fluids flow back to the production area.