Interpretation of the Petroleum Potential of the Darling Basin, a Process of Integration and Iteration

Abstract

With an area of over 100.000 Km2 and sedimentary thicknesses of over 8000 m. the Darling Basin is the largest onshore basin in New South Wales and one of the largest in Australia. In the entire basin only 20 wells have been drilled and approximately 1800 km of multifold seismic recorded. This quantity of seismic is grossly inadequate for a basin of this size and in addition acquisition has been concentrated over regional structural highs. These highs are usually poor data areas due to structural complexity and coupling problems in acquisition related to the high proportion of outcrop. However the available seismic data has confirmed the presence of large structures and the NSW Department of Mineral Resources is now undertaking a major study of the basin?s petroleum potential. The Darling Basin does have fair to good gravity and magnetic coverage and this has provided a solid basis for the current studies of the basin. Interpretations of the potential field data have been made with a view to interpreting the depth and structure of ?basement? and also to interpreting intra-sedimentary structures. The current evaluation of the basin is an iterative process. Recent potential field interpretations have utilised all the available information including seismic, well and surface geology. The Department of Mineral Resources is carrying out seismic programs based on these interpretations of the potential field and other available data. These seismic results are being used to update and modify, if necessary, the earlier interpretations. The seismic surveys as a by-product, have also indicated the existence of more extensive and better outcrop data than had previously been expected and the interpretation, or in some cases reinterpretation, of this outcrop data, is also being incorporated in the current study.