Development of an Electronic Memory Tool for Logging Geothermal Temperature and Pressure Profiles

Abstract

A downhole memory, simultaneous temperature-pressure logging tool for use in geothermal wells has been developed and tested by Contact Energy Ltd., with Spinks Energy Systems Ltd. An electronic log of depth and time on the wireline winch used to run the downhole instrument is recorded on a surface data logger, at the same time as the logging instrument is recording temperature and pressure. By merging the downhole and surface data, logs of time, depth, temperature and pressure are obtained. Thus, profiles of temperature and pressure versus depth or time can be derived. The instrument has an accuracy of better than 0.25"C and 0.03 bar.