Oil to source correlation of Upper Assam Basin oils with pre-Tipam sediments as potential source sequences

摘要

Crude oils occurring in different structures from various stratigraphic sequences of Upper Assam Basin (India) have been studied alongwith the pre-Tipam sedimentary sequences of the basin by source quality and maturity based geochemical parameters to ascertain the types of petroleum system/systems effective in the basin. The study suggests the presence of five oil-source pairs in ONGC's area of operation in Upper Assam Basin: (ⅰ) Barail sediments in Lakwa and Geleki - oils in Girujan Clay, TS-1, TS-2, TS-3 and Barails in Lakwa-Geleki-Rudrasagar area, (ⅱ) Kopili sequence of Geleki and Barail coal shales of Mekaypore area - oils in TS-4, TS-5 and TS-6 of Lakwa area, (ⅲ) Sylhet sediments of the Borholla and Khoraghat - oils in basement and sylhet in this area, (ⅳ) Barail sequences of Khoraghat and Borholla area -oils in Bokabils of Khoraghat area, (ⅴ) Sylhet sequences of Lakwa area -Eocene oil found in Basal Sand Stone in Lakwa-452.