HYDROCARBON POTENTIAL OF THE BATHURST ISLAND GROUP, NORTHEAST BONAPARTE BASIN, IMPLICATIONS FOR FUTURE EXPLORATION

Abstract

Despite 20 years of exploration between 1965 and 1992 in the northeastern part of the Bonaparte Basin, the region remains underexplored. Exploration has produced modest encouragement. The seven wells drilled in the area totalling more than 70 000 km2 include one dry gas and two gas/condensate discoveries. Explorers have targeted the Jurassic Plover Formation and Flamingo Group, but reservoir quality has often been poor in both units due largely to depth of burial.

Recent regional studies of the northeastern part of the Bonaparte Basin, undertaken by the Bureau of Resource Sciences, indicate there is potential for generation and entrapment of hydrocarbons in the Cretaceous Bathurst Island Group. Geochemical results show the lower Bathurst Island Group contains good source rocks that are largely gas prone, but have the potential to charge large Cretaceous traps. Geohistory modelling suggests that the Bathurst Island Group may have entered the oil window around the Middle Cretaceous, after most of the structuring had occurred, and continued until the Middle Miocene or later. Potential reservoirs have been identified in Santonian, Campanian and Maastrichtian sands, and in fractured Albian Carbonates.

Recent reports have predicted that by early next century there will be a significant increase in natural gas consumption in Australia, due to increased use for power generation and transportation, as well as further sales to the Asian market. New methanol technology could commercialise some marginal gas fields. The theme for this years APEA conference is `New Age—New Opportunities'. The Bonaparte Basin may provide the opportunity to explore for and develop new gas accumulations.