SUBSURFACE GEOLOGICAL MODELING OF THE WAYANG WINDU GEOTHERMAL FIELD BASED ON GRAVITY DATA

• Main Author: Simamora, Colombus
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/65806
• Institution: Institut Teknologi Bandung

Indonesia has a total potential of approximately 29 GW spread across 324 prospects throughout Indonesia. One of the geothermal fields in Indonesia is the Wayang Windu geothermal field, Pangalengan, West Java. This study aims to conduct subsurface modeling that develops in the Wayang Windu geothermal field. The research was conducted by using the gravity method analysis which started by processing CBA and topographic data which had previously been obtained by the ITB Laboratorium Exploration Geophysics Team. The results obtained from the processing are complete Bouguer anomaly maps with anomaly values ranging from 8-32 mGal with a base density of 2,67 gr/cc. Then the anomaly separation is performed to obtain the residual Bouguer anomaly using the moving average, second-order polynomial, and second vertical derivative methods. Residual anomalies show anomaly results with values ranging from -4,5 to 5 mGal, -4 to 6 mGal, and -3,5 to 5,5 mGal, respectively. From the residual maps produced by the two methods, the moving average method was chosen because of the better geological correlation. The results from the modeling show magma intrusion from Wayang Windu’s young volcanic rock (?? = +0,25 gr/cm3), which is an aged quarter. The bedrock in this area is interpreted as a tuffaceous breccia unit (?? = -0,5 gr/cm3) with tertiary age. Then the above layer was interpreted as waring gun andesite (?? = -0,7 gr/cm3). Furthermore, the layer above it is an irreducible volcanic loose spice deposit (?? = - 0,25 gr/cm3) which is quaternary in age. There is a pattern of fault structures in the study area according to the study that allows heat flow to reach the surface.