A time-lapse reflection survey for the geothermal reservoir monitoring in Akinomiya geothermal area, Akita pref. Japan

Abstract

In this paper, we would like to examine the applicability of the time-lapse seismic reflection survey to the geothermal reservoir monitoring. Akinomiya geothermal area, Akita pref. Japan is the study area where four-month steam production test was performed. The baseline and monitoring surveys were conducted just after and one year after the test. Because the maximum reservoir pressure difference and minimum seasonal difference are satisfied simultaneously. We find the similarity and difference in the results of the baseline and monitoring surveys which suggests the large scale geology and the change occurred in the reservoir, respectively. We also demonstrate the possibility of the simple 3-D survey named ``handy 3-D'. In the survey, vibrator shot points are located on the roads and the reservoirs are deployed as 3-D patch. If it is successful, number of the seismic reflection surveys carried out in the mountainous areas will be encouraged.