Mineralogical modelling and petrophysical parameters in Permian gas shales from the Roseneath and Murteree formations, Cooper Basin, Australia

To estimate the resources of Permian Roseneath and Murteree gas shales in the Cooper Basin, Australia, geochemical analysis, log interpretation and core analysis techniques were combined to conduct mineralogical modelling and define petrophysical parameters of both formations. With the sedimentologic, petrographic, SEM and XRD data derived from analysis of cores and cuttings, a mineralogical model was built for target formations. Moreover, based on the results of conventional core analysis, wireline logging, SEM analysis, XRD analysis, and geochemical and petrographic analysis, a petrophysical model was established for key wells. Then, these models were used to analyse the mineral composition and petrophysical properties of Roseneath and Murteree gas shales. The results show that both Roseneath and Murteree gas shales are composed of clay, quartz, carbonate and kerogen, as well as a small quantity of auxiliary minerals (e.g. feldspar and siderite). According to porosity, permeability, TOC, water saturation, mineral composition and other parameters, it is concluded that Murteree shale has higher potential than Roseneath shale within the basin, except for areas in and around Well Encounter 1 where Roseneath exhibit excellent potential. Key words: shale gas, mineralogical modelling, petrophysical properties, Cooper Basin, Permian Roseneath Formation, Permian Murteree Formation