Geomechanical rock properties of the Officer Basin

Abstract

The Officer Basin spanning South Australia and Western Australia is the focus of a regional stratigraphic study being undertaken as part of the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to increasing investment in resource exploration in Australia. Despite numerous demonstrated oil and gas shows, the Officer Basin remains a frontier basin for energy exploration with significant uncertainties due to data availability. Under the EFTF Officer–Musgrave Project, Geoscience Australia acquired new geomechanical rock property data from forty core samples in five legacy stratigraphic and petroleum exploration wells that intersected Paleozoic and Neoproterozoic aged intervals. These samples were subjected to unconfined compressive rock strength tests, Brazilian tensile strength tests and laboratory ultrasonic measurements. Petrophysical properties were also characterised via X-ray computerised tomography scanning, grain density and porosity-permeability analysis. Accurate characterisation of static geomechanical rock properties through laboratory testing is essential. In the modern exploration environment, these datasets are a precompetitive resource that can simplify investment decisions in prospective frontier regions such as the Officer Basin.

Exploring for the Future: new geomechanical data in frontier Australian basins

“…7g). Bailey et al (2022d) present lithology specific conversions and demonstrate that, from the analysed samples, a generic conversion of E stat = 0.6 × E dyn provides an effective relationship for estimating Young's modulus in the Officer Basin. As expected, comparison of v stat and v dyn shows no meaningful relationship, with R 2 values of 0.0519 and 0.0014 for shales and sandstones, respectively (Fig.…”