Delineating Sub-basins of Sedimentary Rock Structure beneath Eastern Central Sumatra Basin Using Integrated Gravity, Seismic and Well Data Analysis

Abstract

Abstract The Central Sumatra Basin is a vast sedimentary basin and has been proven to produce hydrocarbon; this basin consists of several different sub-basins that cannot be well-imaged with conventional seismic reflection section and limited well log data. This research aims to delineate sedimentary sub-basins, interpret the sub-surface geological model and identify geological structures beneath Eastern Central Sumatra Basin using integrated geophysical gravity, seismic and well data analysis. The sub-basins that can be delineated from the gravity data analysis are 13 sedimentary sub-basins, while the structural patterns identified are basement height, graben and fault. The 3D modeling results indicate that the Pre-Tertiary granitic basement is a continental crust with a mass density value of 2.67 gr/cc. Sedimentary rock from modeling results from the bottom to up, which is Early Oligocene-Middle Miocene sedimentary rock with a mass density value of 2.35 gr/cc. The results of the sub-surface geological modeling analysis show, based on the graben pattern and the basement high beneath the Eastern Central Sumatra Basin, many structural patterns support the development of petroleum systems similar to the western part of the basin that has already produced hydrocarbon. Our study also revealed the thickness of the Sihapas Formation, which is believed to have hydrocarbon reservoir potential.