GEOTHERMAL (HEATFLOW) MAP OF THE SOUTH SUMATRA BASIN

We are compiling a geothermal map of the South Sumatra Basin. Sumatra is the largest island in Indonesia, with three main oil producing basins: North, Central and South. A geothermal map is a heat flow map illustrating the natural heat loss from the interior of Earth to the surface. Our methods are based on previously published work in North America (Dr. D. Blackwell from SMU Geothermal Laboratory), which uses both the temperature gradient at a specific location and the thermal properties of the rocks at the same location to calculate heat flow values. This information can be calculated from well log data available at Ball State University. This data is part of the geophysical database of the South East Asia- Pacific region, donated by L. Bogue Hunt; commonly known as the “LBH Database”. It contains physical, lithological, and paleontological logs, seismic sections, structural maps and detailed geological reports of many exploration sites.

Our initial study will focus on the southern region of Sumatra and covers an area roughly 200km². Bottom hole temperatures (BHT) will only be used from wells deeper than 100m. Preliminary analyses suggest the map will be based on more than 500 BHT points. When available, geothermal spring data will be incorporated into the map. Contouring and gridding will be completed using Golden Software ® program Surfer.

In 2011, Indonesia ranked 21^st globally in oil production, with most of the oil produced in Sumatra. The region has been subjected to intense tectonic activity, specifically subduction of the Indian-Australian Plate under the Sunda Plate and rifting. The area contains a large number of structural-rift basins, ideal for oil accumulation, however, it is complicated by volcanism and geothermal activity. As such, a geothermal (heat flow) map of the region is important not only for petroleum exploration, but also for mineral exploration and alternative (geothermal) energy development.