Sub-Basin Delineation and Subsurface Geological Interpretation of the Bangka Basin Using High-Pass and Low-Pass Filterswith 2D and 3D Modelling Based on Gravity Data Analysis

Abstract

Indonesia is one of the countries that has significant oil and  gas  potential  in  the  world.  This  is evidenced by the results of an atlas study of sedimentary basins which mapped 128 sedimentary basins. Based on the large number of sedimentary basins in Indonesia, it is necessary to investigate these sedimentary basins for further exploration. One of these basins is the Bangka Basin. This study uses Topex satellite data, with the aim of delineating sub-basins in the Bangka Basin. Gravity data analysis was carried out using spectral analysis techniques, high-pass and low-pass filters, theta filter, forward modelling, and inverse modelling. The results of the spectral analysis show that the average thickness of sedimentary rocks in the study area is around 2.45 km, while the sub-basins that can be delineated are 7 (seven) sedimentary sub-basins. Two cross sections were used in forward modelling, section A - A’ and section B - B’. The maximum sediment thickness on the two sections is 3.47 km and 3.78 km. The average sediment thickness on the two sections is 2.46 km and 2.48 km. The results of inverse modelling are presented as 3D models and have a density distribution of 2.25 – 2.8 gr/cc and a depth of 10 km. In addition, inverse modelling presents the 2D model for comparison with the forward modelling results on the same trajectory. The maximum difference in sediment thickness is 0.23 – 0.32 km and the average thickness is 0.07 – 0.14 km.