A thermal maturation study of the Carnarvon Basin, Australia and the northern North Sea, Europe

Abstract

The suppression of vitrinite reflectance can cause problems for the oil industry if not properly considered. The scope of this paper is to emphasise the errors that suppression could lead to in the estimation of heat flow and transformation ratio of hydrocarbons. Two cross-sections from the Carnarvon Basin, North West Shelf, Australia, are modelled and compared to a model from the North Sea of Europe, in order to study the effect of suppressed vitrinite reflectance in a sedimentary basin. The North Sea modelling implies that neglecting the suppression effect of the vitrinite reflectance could lead to the heat flow being erroneously estimated by as much as almost 40% (40 mW/m2 instead of 55 mW/m2). Further, modelling of the Australian profiles suggest that the local effect might be even higher. This will lead to an underestimation of source u rock maturity. As a result of this underestimation of the source rock maturity. maior errors will occur in the predictions of the transformaratio of hydrocarbons and thereby the quantity of generated hydrocarbons.