Hydrocarbon source systems in relation to crude oil occurrences in Bombay Offshore Basin, India

摘要

A study of source rock parameters of some key exploratory wells indicates that Lower Eocene to Paleocene Panna Formation is the major hydrocarbon source sequence in all four petroliferous tectonic blocks of the basin. The Panna Formation in the central graben and B-59 areas of Heera-Bassein block has the highest TOC and S2 values and shows positive correlation with Heera-Bassein and Bombay High oils which are derived from terrestrial source organics deposited in deltaic environment. Panna Formation in the Ratnagiri block has geochemical parameters similar to the Ratnagiri oils though the studied sediments have lower maturation levels. Ratnagiri oils are derived from mixed source organics deposited in lacustrine environment. The oils of DCS area / Panna oils of BH and the oils/condensates of Tapti-Daman show some differences in the triterpane and C-isotopic composition as compared to HB/BH oils and are possibly derived from Panna sequence in the paleosink south of BH and in the Surat Depression respectively.