Source Rock Evaluation and Hydrocarbon Potential in the Tano Basin, South Western Ghana, West Africa

Abstract

Three exploratory oil wells (ST-9H, WCTP-2X and WT-1X) from the Tano Basin, south-western Ghana, have been evaluated for their hydrocarbon generation potential by the use of geochemical analysis (TOC, Rock-Eval pyrolysis). The analytical results of samples revealed that the wells have fair to good total organic carbon (TOC) contents, suggesting that there exist conditions in the Basin that favoured organic matter production and preservation. There is a variation in kerogen types and this may be attributed to the relative stratigraphic positions of the outcrops within the basin. Thermal maturity indicated that samples from the well WCTP-2X and WT-1X, are immature and that from ST-9H show late immature to mature stage of the hydrocarbon generation process. Most of the samples from the wells with the exception of two samples from ST- 9H are non-indigenous (migrated). Hydrocarbon generation potential from all three wells particularly ST-9H display sufficient organic matter contents to produce oil and gas. The hydrocarbon potential is good and capable to make expulsions of oil and gas from the wells. Kerogen Type IV, III and II are present in well ST-9Hand Types II and III kerogen in wells WCTP-2X and WT-1X.