Geothermal Conceptual Model of Talu-Tombang West Pasaman, West Sumatera Based on 3G Data Studies

Muhammad Alzaid Ponka; Niniek Rina Herdianita; Prihadi Sumintadireja

Muhammad Alzaid Ponka Geological Engineering Master Study Program, Faculty of Earth Science and Technology, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia
Niniek Rina Herdianita Research Group of Petrology, Volcanology, and Geochemistry, Faculty of Earth Science and Technology, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia
Prihadi Sumintadireja Research Group of Applied Geology, Faculty of Earth Science and Technology, Institut Teknologi Bandung, Jalan Ganesa 10, Bandung 40132, Indonesia

Keywords: conceptual model, geothermal, Pasaman, Talu-Tombang, West Sumatera

Abstract

Talu-Tombang geothermal system is one of the potential geothermal resources in West Sumatera. This geothermal system is indicated by the presence of warm water pool as surface manifestation at Talu (TA 1 and TA 2) and Tombang (TO 1 and TO 2). This study aimed to develop a conceptual model of the Talu-Tombang geothermal system. This study includes geology, fluid chemistry, gravity, and geoelectrical DC resistivity survey. Lithology present in the study area is Pre-Tertiary metamorphic rock, Tertiary sedimentary rock, Quaternary volcanic rock and alluvial. The existence of manifestations in this area is associated with NW-SE and NE-SW fault systems. The chemical analyses show that Talu waters have HCO3-Cl type and Tombang waters are SO4-HCO3 type. Result from the gravity survey shows the high residual anomalies of more than 30 mGal in the middle of the study area indicating an intrusion rock; the intrusion might act as a heat source. Reservoir fluid is meteoric water origin. Based on resistivity data, the low resistivity value below 100 Ohm-m is associated with alluvium product at the eastern area. Based on 3G data, the geothermal system has two reservoirs, i.e. Talu and Tombang reservoirs. Geothermometer of K/Mg show reservoirs have temperatures of 150±10°C.

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