Unconventional Prospectivity Evaluation of Kidson Sub-basin, Canning Superbasin, Western Australia - Sleeping Giant?

The Kidson Sub-basin lies within latitudes 20°S and 24°S and longitude 123°E and 128°E and is one of the depocentres formed during the development of the Canning Superbasin in the Early Paleozoic in Western Australia. Hydrocarbon discoveries have been made over the years in some parts of the Canning Superbasin but none in the Kidson Sub-basin. This report evaluates the prospectivity of Kidson Sub-basin for unconventional hydrocarbon resources. The Kidson Sub-basin has a sedimentary section thickness reaching up to over 7000m, mainly of Paleozoic age. Using the available well data three unconventional shale gas plays within the Goldwyer, Bongabinni and Noonkanbah shales are interpreted to meet all the necessary requirements for hosting shale gas accumulations. A pseudo-well modelled near the centre of the Kidson Sub-basin shows that the organically-rich Noonkanbah Formation is mature enough to generate gas and 1-D modelling of the Kidson-1 well indicates that both the Bongabinni and Goldwyer Formations are also presently in the gas window. The prospective resources of the unconventional shale plays are estimated using geochemical approach. The Goldwyer Shale is estimated to contain potential gas in-place (GIIP) of about 13.4TCF over the most prospective area of Kidson Sub-basin estimated to be around 567 km2. The Bongabinni Shale is organically-rich and about 324 km2 is estimated to be prospective in the Kidson Sub-basin. About 205 km2 is estimated to be prospective in the centre of Kidson Sub-basin where Noonkanbah Shale is deeply buried to a depth up to 1600m. The three shale plays have mid range gross prospective resources of 31.0 TCF of gas. The current skilled labour shortage in Australia may pose a big challenge in shale gas production as this will lead to higher drilling costs compared to those of United States. In addition, Kidson Sub-basin is a desert and water scarcity will be another challenge for shale gas production since water is required for fraccing.