COMMON CHARACTERISTICS OF PUMPED WELLS IN GEOTHERMAL POWER PROJECTS

Abstract

Pumped wells in geothermal power projects share common characteristics, including the requirement for sufficient dynamic water level in the well above the pump to preclude gas breakout on the suction side of the pump. This dynamic water level is a function of resource temperature, static water level, flowrate, and well productivity, the interrelationship for which is explored in this paper.
A broad overview of existing pumped-well geothermal power projects is presented, including the range of fluid utilization (flowrate divided by power output). Discussions are presented on pump hydraulics and the influence of resource temperature and static water level on allowable drawdown and the corresponding minimum well productivity indices for a given power output.
The overarching purpose of this paper is to present together in one place the key elements of geothermal pumped wells that will aid the reader in understanding fundamental characteristics of pumped wells in existing power projects as well as potential expansions or greenfield sites.