Structural and Reservoir Development of the Western Papuan Basin Gas and Condensate Fields

Abstract

The Stanley, Elevala, Ketu and Ubuntu gas-condensate fields are located within the foreland of the Western Papuan Basin, Papua New Guinea. Interpretation of 2D seismic across the basin has revealed the importance of Basement architecture and the regional Northwest trending 3KB fault system for trap and reservoir development. The Miocene/Pliocene compression, responsible for the thrust structures of the Papuan Foldbelt, had a relatively minor topological impact in the foreland. However, trap development within the Western Papuan Basin was influenced by this compression through inversion of pre-existing faults and enhancement of compactional drape of reservoirs over pre-existing Basement highs. Economically viable reservoirs (Elevala, Toro and Kimu Sandstones) have been intersected by several exploration and appraisal wells in the Western Papuan Basin. The Kimu and Elevala Sandstones are absent in the main producing fields of PNG, consequently very little is known about the depositional controls of these reservoirs. A detailed reservoir characterisation study was required to underpin foreland resource development and evaluate potential hydrocarbon recovery. Geophysical reservoir characterisation techniques were of limited value due to the poor vertical resolution of the reservoir on the 2D seismic, therefore core data and sedimentary analogues were used to map the spatial distribution of reservoir sands and develop palaeogeographic models. Horizon Oil’s activities within the Western Papuan Basin have contributed to the understanding of the structural regime and reservoir development of the area, proved commercial resources and highlighted numerous prospective structures. The purpose of this paper is to present these findings from a relatively under-reported region of PNG