Interpretation and Modelling of the Pedirka Basin (central Australia) using Magnetics, Gravity, Well-log and Seismic data

Abstract

The Pedirka Basin of central Australia remains a frontier for petroleum exploration. Cost saving methods for exploration exists with publicly available high quality magnetics and regional gravity datasets. This data has been combined with available seismic sections and well logs to assist in gravity 2D section modelling and magnetic 3D geophysical inversions. The resulting magnetic susceptibility voxel when clipped to 0.012 SI units suggests a top depth to basement of ~5500m on the selected Simpson gravity modelled geology section. The basement of the Pedirka basin region shows a significant heterogeneous nature in surface and well samples and in the modelled densities and magnetic susceptibilities. The heterogeneity is suggestive of Proterozoic granite systems having undergone convective fractionation. Thermal gradients point to a break down in magnetic minerals at depths greater than 15km. Outcropping of the Mereenie sandstone has been utilised to confirm the negligible influence of sedimentary units on magnetic signatures below 600m depth.