Research paperA comparison of North American shale plays with emerging non-marine shale plays in Australia

- The petrophysical properties of North American and Australian shale plays are compared.
- Established Crossplots of marine shales are not applicable to non-marine shales.
- Australian shale plays are less brittle compared to North American shale plays.
- Empirical relationships are developed for Cooper basin shales.

Geological and petrophysical parameters are critical in evaluating the production potential of prospective shale gas plays and their economic viability for commercial development. However, based on the US experience, these characteristics can vary widely. Furthermore, the non-marine shale plays of the Cooper Basin, South Australia are distinctively different from the marine shale plays in the US. Non-marine shale may consist of higher clay content and, thus, may be less responsive to hydraulic fracturing due to the increased ductility. Conversely, the availability of sufficient amounts of quartz and siderite may counteract this effect and maintain brittleness. In this study, the mineral, total organic and gas content, thermal maturity, Poisson's ratio and Young's modulus data obtained from the Roseneath and Murteree formations of the Cooper Basin have been compared with US shale formations. The results show that the formations compare well in terms of thickness, thermal maturity, Young's modulus and Poisson's ratio, but not in clay mineral content and formation temperature and values for TOC, porosity and gas-in-place are comparatively lower. To determine whether such plays are economically viable will require technical, as well as economic, analysis of the hydraulic fracturing process, including the potential for horizontal and vertical well development or basin centred gas developments. A shale play that has unfavourable prospects may have upfront infrastructure and major capital costs that outweigh the potential receipts from gas production.