Influence of Borehole Capacity on Pressure .buildup During Cold-Water Injection

Abstract

Pressure-transient testing of wells is lhe standard procedure for estimating, the transmissivity structure of geothermal reservoirs. While long-term discharge/buildup tests involving downhole pressure measurements in both the flowing wells and nearby shut-in observation wells are to be preferred. Relatively short-term cold-water injection tests are routinely carried out shortly after well completion in Japan. Typically. substantial amounts of data of this type are obtained before long-term discharge tests are performed during the exploration and preliminary development of a new geothermal prospect. In recent years it has become common practice to employ downhole instruments which record the pressure (and occasionally temperature) of the well feedzone during and after injection testing.