Inversion Modelling 3D Gravity for Hydrocarbon Identification at Sanggau, West Borneo

Abstract

Inversion modelling 3D in gravity is applied on Sanggau Quadrangle, West Borneo. Subsurface modelling by gravity methods has ambiguity, to solve this ambiguity invers modelling 3D has been applied to anomaly bouguer map with measurement of depth by spectral analysis. Invers modelling 3D use inversion method of singular value decomposition (SVD) and inversion Occam. Anomaly bouguer show low anomaly between -83.5 mGal to 184 mGal in the north and south of map, middle anomaly between 184 mGal to 315 mGal in the middle of the map, high anomaly has values between 346.5 mGal to 544.7 mGal in North-East. Spectral analysis have result of the regional depth 30.381 km. Invers modelling 3D has result the model that have RMS 0.063 and 0.02. Invers modelling 3D shown large thickness of sandstone with density 2.35 g/cc at Kayan High Land, Ketungau Low Land, and Kapuas Low land, that potential for hydrocarbon. Volume sandstone on Sanggau is predicted about ≤ 50892.19384 km3. The result of the model give preliminary information of model concept on estimated potential hydrocarbon.