A study of the effects of various reservoir parameters on the performance of geothermal reservoirs

Abstract

This paper presents a study of three liquid dominate geothermal reservoir systems. The effect of production rate on the ultimate heat produced and on the behavior of the steam/water ratio was studied for a reservoir with no water recharge and a reservoir with a limited water influx. Production rates of 1000 BWPD/acre to 50,000 BWPD/acre were used. The effect of high rate of water influx was studied using production rates of 10,000 BWPD/acre and 70,000 BWPD/acre. A one-dimensional numerical model was developed to simulate the geothermal reservoirs. The effects of gravity, capillary pressure, phase change, heat conduction, and heat convection are considered in the model. It was found that the total amount of heat which can be produced from a geothermal reservoir is limited and that to obtain the most heat, the reservoir pressure should be reduced enough to cause the superpressured water to flash to steam in the reservoir. It was found that the recharge of heat to the reservoir by conduction or from water influx resulted in little additional heat recovery.