| Abstract |
Some production wells in the Mahanagdong geothermal field have positive Calcite Saturation Indices (CSI) at lower flash point temperatures as calculated using the WATCH speciation program. From the start of production in 1997, the calcite-scaling wells have shown progressive decline in output as a result of mineraldeposition and constriction in the wells' internal diameter. In 1999, injected brine was observed to be returning to three production wells and has caused marked dedine in the CSls of the wells. 738 invading fluids increased the reservoir chlodde concentration and lowered the discharged C02 and the temperature of the well nearest to the injection sink. The carbonates of the deep fluids also decreased with the decline of dissolved C02. Since these species participate in the formation of calcite scales &a2+ + 2HCO; = CaCO3,, + C02? + HzO), their decline lowered the CSI. The disfn'bution of injection load was optimized in order to continuously provide mass recharge without necessarily cooling to the production wells. The modified injection strategy also aims to lower the potential for calcite deposition and effectively decrease the noncondensible gas content of the steam delivered to the power plants. |