MAGNETOTELLURIC METHOD APPLIED FOR EXPLORATION OF GEOTHERMAL RESOURCES IN SUMATRA

Abstract

Pertamina has conducted geothermal exploration in Sumatra showing that the depths to the top of most of the geothermal reservoirs are about 1000-2000 meters. Previous geophysical exploration work by
Pertamina emphasized the use of DC-resistivity methods such as the Schlumberger method. However, these techmques can typically only
penetrate to a depth of less than 1000 meters and are too shallow to map the geothermal system in most areas. With the magnetotelluric (MT) method, investigation to depths of greater than 1000 meters
are routine, which gives the explorationist a better picture of the deep resistivity structure. Pertamina now applies MT methods to explore for geothermal resources in most area. In conjunction with the MT
data. time-domain electromagnetic (TDEM) data are usually measured to correct for static effects in the MT data.