Depositional sequence interpretation using seismic and well data of offshore Central Sumatra Basin

Abstract

Offshore Central Sumatra Basin is an integral part of Central Sumatra Basin known for producing hydrocarbon basins. The derivation of stratigraphic study of seismic and well data is intended to improve accuracy of geological interpretation. Sequence stratigraphy studies have a significant role in exploratory studies to determine which depositional sequence can be inferred as hydrocarbon reservoir and its correlation in petroleum system. This study aims to identify biogenic gas sequential interpretation using seismic and well data of offshore Central Sumatra Basin. The procedure to analyze sequence stratigraphy is to identify stratigraphy surface markers using GR log, then map these markers to the seismic section that has been tied with good data to determine the distribution of each stratigraphy sequence. This study area has five depositional sequences, which are predominantly formed in marine depositional environments. Potential source rock in this area is at DS-1 which has a lacustrine depositional environment with euxinic conditions. The euxinic shale at the upper TST-1 deposit could be a source rock with hydrocarbon migration through faults. Biogenic gas reservoir potential is in Petani Formation (DS-5). Shale in MFS-5 and HST-5 could be a hydrocarbon trap, whereas LST-5 and TST-5 sandstone deposits can be a reservoir.