A Review of LBL Geothermal Well Testing Equipment

Abstract

A high temperature and hostile environments of geothermal reservoirs have presented the use of high precision downhole well testing instrumentation. For the measurement of temperature, pressure, and flow at temperatures in excess of 150°C, reservoir engineers have had to rely on less accurate non-electrical instrumentation. Sandia's development of high temperature electronics and the introduction of high temperature cable has now increased the temperature range of certain instruments utilizing downhole active electronics to 275°C. However, this instrumentation is not yet commercially available. Development of high temperature instrumentation with moderate accuracy utilizing passive electronics downhole has only been limited by the non-availability of high temperature multi-conductor cable. With the recent introduction of 275°C multi-conductor cable, the simultaneous measurement of moderate to high precision temperature, pressure, and flow is possible this year. The accurate measurement of two phase flow at the surface will also soon be technically possible. The involvement of the LBL Geothermal Reservoir Group in the development and evaluation of geothermal well testing instrumentation is presented.