An Evaluation of the Petroleum System - Offshore Morondava Basin, Madagascar, Based on 2D Seismic Data Interpretation

This study addresses the regional interpretation of 2D seismic data acquired in 2003 and 2005-2006 by TGS-NOPEC integrated with satellite gravity data and source rocks modelling to analyze the petroleum system of the offshore part of the Morondava Basin (Madagascar). Seismic and satellite gravity data interpretation suggests that the western coastal basins of Madagascar can be split into two tectonic provinces i.e a western passive margin and an eastern failed rift. The structure, depositional environments and burial histories of these two provinces are quite distinct. Hence, the potential petroleum systems that occur in each province are also different. The offshore part of the basin is under-explored but found to be highly prospective. Evidences of direct hydrocarbon indicators have also been found. The burial and hydrocarbon expulsion histories for source rocks of Permo-Triassic and Mid Jurassic ages were modelled and encouraging results have been seen. The structuration happened before the oil expulsion from these source rocks which maximize the chances of finding hydrocarbons in place. Potential good quality reservoirs including predominantly sandstones and limestones have been interpreted which are covered by interbedded seals. Hence, all elements of an effective petroleum system were identified during this study.