ANALYSIS OF THE DAMPIER SUB-BASIN PETROLEUM SYSTEMS USING INTEGRATED 2D MODELLING TECHNIQUES

Abstract

Determining the controls on subsurface pressure, and describing fluid flow within the petroleum systems of the North West Shelf's Dampier Sub-basin, were the primary aims of this work.

The study was conducted using Temispack, an integrated forward modelling software package developed by the Institut Français du Pétrole (IFP). Three southeast-northwest trending regional seismic lines were modelled, utilising numerous well penetrations for pressure and temperature calibration, lithological and stratigraphical control. Once a detailed understanding of the regional controls on fluid flow and abnormal pressure distribution had been determined, pre-drill predictions were then made to aid the planning and safe completion of a 1996 exploration well.

The primary conclusions of the study are that: a) three intervals constitute significant regional aquifers and alleviate overpressures in even the most remote locations of the Dampier Sub-basin-The Tithonian Angel Sands, Bathonian Legendre Sands and Upper Triassic/Lower Jurassic Sands; b) two intervals are capable of producing severe overpressures-The Muderong Shale and any fine-grained Jurassic sections devoid of lateral carrier beds; and c) with a full and accurate knowledge of structure and stratigraphy, the pressures at a drilling location could be accurately predicted using the 2D basin modelling approach.