Interference of Production between Two Wells during a One Month Circulation Test at the Hijiori Hot Dry Rock Test Site

Abstract

In 1995, a one-month circulation test (Exp.9501) was carried out with HDR-1 as an injection well and HDR-2 and HDR-3 as production wells at the Hijiori HDR site in Yamagata prefecture, Japan. There are two reservoirs in a high temperature granite at the site. Exp.9501 was the first circulation test to evaluate characteristics of the deeper reservoir at about 2200 m deep and was a preliminary test for the subsequent two-years circulation test. The interference between the two reservoirs was observed because of water level changes in production wells. This observation was simulated by using a wellbore heat transfer ( WBHT) code and concluded that this could occur when downhole pressure changed by heating up of the wellbore. Geochemistry of the produced fluid support this conclusion.