1991 Volume 13 Issue 1 Pages 45-53
Results of pressure build-up tests carried out in 1986, 1987 and 1988 on M-7, a dry steam well in the Matsukawa vapor-dominated geothermal field in Northeast Japan, are reported. Pressure buildup data observed at the well-head show clear semi-log straight lines in the three tests. Condensation effects in and/or around the well were clearly observed. The results suggest that steam pressure and temperature in the vicinity of the well were constant through October 1986 to February 1988. A change in the magnitude of damage with time was observed as a change in the skin factor.