Petroleum Source Rock Properties of Surma Group Shales of Bengal Basin, Bangladesh

Bangladesh (a major part of Bengal Basin) is situated at the northeastern corner of Indian subcontinent and it is extending to the Bay of Bengal. In this present paper, the hydrocarbon source rock properties have been discussed on the basis of the organic geochemical and petrological methods. A total of eight shale core samples were collected from eight different wells of respecting eight gas fields covering the entire Deep Basin, the most important tectonic unit of Bengal Basin. All of the shale samples were chosen from the Surma Group. The samples have been crushed to fine powder and subsequently analyzed using Source Rock Analyzer-SRA (i.e., Rock-Eval equivalent). The Soxhlet’s equipment was used for extracting EOM which were subsequently fractionated into aliphatic, aromatic and NSO. The polished blocks were used for petrographic analysis using a Leica CTR 6000-M microscope with white and ultraviolet (UV) light sources. The extracted organic matter of the investigated shale samples is mainly Type III together with minor contribution of Type II kerogen as indicated by the SRA and petrographic data. The hydrocarbon source potential has been deduced as poor to good quality. The studied Surma Group shales represent an immature to early mature oil window.