Interpretasi Data Gravity dan Magnetik dalam Penentuan Permeabilitas dan Sumber Panas Lapangan Panas Bumi Montelago Filipina
Montelago geothermal field at Philippines is a heat sweep low terrain non volcanic type of geothermal system. Several researches has been conducted at Montelago prospect in order to study geothermal system components such as heat source and reservoir. Gravity and magnetic as geophysical research has also conducted at Montelago area for fault structure identification, heat source location, and also reservoir thickness study. Good permeability has probability for controlling thermal fluid at geothermal system, this permeability will be associated with subsurface fault structure.
Fault structure, permeability zone, heat source and reservoir thickness study at Montelago area can be identified by low gravity anomaly, low magnetic anomaly, and additional data such as low resistivity, geology and geochemistry. Gravity anomaly has been analyzed from residual anomaly, the result of derivative calculation anomaly, and also forward modeling.
Generally, there are three fault structure direction at Montelago area: Northwest-Southeast direction, Northeast-Southwest direction and North-South direction. The result indicates three permeable zone and one prospect zone in the middle of Montelago area which associated by Northwest-Southeast fault structure. Montelago reservoir thickness was predicted about 2400 m, delineated from resistivity data and gravity forward modeling. Montelago heat source probably located at Southeast of Montelago area which is below of reservoir area.
Dr. Eng Suryantini ST. Dipl. Geothermal Tech., M.Sc