Reservoir quality of the Late Cretaceous Volador Formation of the Latrobe group, Gippsland Basin, Australia: Implications from integrated analytical techniques

Abstract

Increasing demand for energy due to the populous Eastern Australia has driven oil and gas industries to find new sources of hydrocarbons as they are the primary energy suppliers. Intensive study has been done on the Volador Formation in the Gippsland Basin by means of core-based petrophysical, sedimentological, and petrographic analyses as well as well log-based interpretation and capillary pressure test. Five wells from Kipper, Basker and Tuna fields with available dataset were investigated in this study: Kipper-1, Basker-1, Basker-2, Basker-5 and Tuna-4. Overall, the formation has good reservoir quality based on the high porosity and permeability values obtained through core and well log petrophysical analyses. The formation made up of mostly moderate to coarse quartz grains that has experienced strong anti-compaction and is poorly cemented. Montmorillonite and illite clays are seen dispersed in the rock formation, with the minority being mixed clays. These clays and diagenetic features including kaolinite cement and quartz overgrowth that can lead to porosity reduction only have insignificant impact on the overall reservoir quality. In addition, capillary pressure data shows that most samples are found in the transition to good reservoir zones (<50% saturation). The results obtained from this study have shown that the Volador Formation in the Gippsland Basin is worth for hydrocarbon exploration.