Development Model for Geothermal Reservoirs

Abstract

The deliverability of liquid-dominated geothermal reservoirs is presented in terms of reservoir performance, inflow performance, and wellbore performance. Water influx modeling is used to match the performance of Wairakei in New Zealand, and Ahuachapan in El Salvador. The inflow performance is given in terms of a linear productivity index for liquid-only flow, and a solution-gas drive relationship for two-phase flow. A 9-5/8 in. production well is assumed, flowing 250°C water from 900 m depth, and with a wellhead pressure of 100 psia. A geothermal development model that couples reservoir deliverability and power plant performance is used to illustrate how the development cost of geothermal electric power projects can be estimated.