The results of a source rock study of the Bass Basin by the Bureau of Mineral Resources (BMR) and the Commonwealth Scientific and Industrial Research Organisation (CSIRO), with emphasis on the Eastern View Coal Measures, have been used in an evaluation of the petroleum potential of the basin. Geochemical analyses, including pyrolysis by the Rock-Eval method, were carried out on 29 core samples from 11 wells. Vitrinite reflectance determinations were made for each sample, and descriptions of organic matter on selected samples. The vitrinite reflectance determinations, in common with those made by previous workers, and the geothermal gradients indicate that, with the exception of Cormorant No. 1, none of the wells is deep enough to have penetrated a mature source rock section. The deeper wells in the basin centre, and wells on the southwest flank in the vicinity of the Pelican field, appear to have been terminated just above the zone of initial hydrocarbon generation. The analytical results for samples from the Eastern View Coal Measures indicate a good source potential for the Paleocene to Early Eocene (Lower M. diversus palynological zone) section, both in the deep basin and on the flanks, and a more variable, but fair to good, potential for the overlying Early to Late Eocene section. Kerogen type was determined microscopically in samples from only four wells: Bass No. 3, Aroo No. 1, Poonboon No. 1, and Cormorant No. 1. The samples were found to contain predominantly gas-prone kerogen, in keeping with the interpreted delta-plain depositional environment, although minor, more oil-prone kerogen was also detected. The study has confirmed the occurrence of potential source rocks in both the Upper and Lower Eastern View Coal Measures, but indicates that the best potential is in the Paleocene to Early Eocene Lower Eastern View Coal Measures in which most of the hydrocarbons detected to date have been located.
