Unconventional resource evaluation: Kockatea shale, Perth basin, Western Australia

Abstract

Organic-rich shales occur in the Kockatea Shale Formation, Permo-Triassic of the Perth Basin (Western Australia) and have been investigated to characterise it as a potential shale gas unit. Classic sedimentological investigation methods, including core descriptions and thin section microscopy, were coupled with standardised organic geochemical analysis procedures, such as TOC determination and Rock-Eval pyrolysis, as well as maceral composition analysis and vitrinite reflectance (Ro) measurements. The Kockatea sediments show a trend of increasing maturity from north to south, with Ro values ranging from 0.6 to 2%, pointing to a thermal maturity between the wet and dry thermogenic gas window. The organic matter is a mixed Type II/III kerogen and hydrogen index (HI) values range from 0.1 to 662 mg HC/g rock, with total organic carbon (TOC) contents between 0.02 and 12.64 wt% and an average formation thickness of 337 m. These interdisciplinary data and methods point to a good potential of the Kockatea Shale Formation for shale gas exploration in Western Australia.