3D Structural and Petrophysical Modelling for Reservoir Characterization of the Poseidon Gas Field, Browse Basin, NW Shelf, Australia

Abstract

This study presents an integrated reservoir characterization of the Poseidon Gas Field, located in the Browse Basin, offshore northwestern Australia. The field, known for its complex geological structure, was investigated using a multi-disciplinary approach that combined petrophysical analysis, 3D seismic interpretation, and structural modelling to delineate key reservoir properties and improve understanding of subsurface architecture to support hydrocarbon exploration and development strategies. Petrophysical analysis of well log data, including gamma-ray, resistivity, density, and neutron logs, was conducted to estimate porosity, permeability, and fluid saturation. Results revealed significant spatial variability in porosity (2–26%) and permeability (300–1700 mD), with higher porosity zones concentrated in the northeastern part of the field. These findings provided essential insights into the reservoir's storage and flow potential. Key structural features, including faults and horizon surfaces, were mapped to understand reservoir compartmentalization and identify potential hydrocarbon traps. Structural analysis indicated the presence of normal fault systems that significantly influence reservoir continuity and trap configurations. A 3D stochastic model incorporating seismic, petrophysical, and well log data was developed to visualize the spatial distribution and heterogeneity of the Plover Formation reservoirs. The model highlights the dominance of sand and silt facies with high hydrocarbon saturation (~ 80%). The integrated analysis confirms the presence of laterally continuous yet heterogeneous reservoirs between 4000 and 5500 feet, with promising hydrocarbon potential. The study enhances the geological understanding of the Poseidon Field and offers valuable input for reducing exploration risk, optimizing well placement, and improving recovery efficiency in similar deepwater gas reservoirs.