Publications

Gas production from the Ruby Field, located in the South Makassar Basin, proves the presence of a debris flow carbonate play, comprised of re-deposited carbonate from an extensive carbonate platform that has been eroded and transported into the deeper water basin. The gas-bearing reservoir of the Ruby Field is the Berai Formation carbonate of Late Oligocene age, which was deposited in a deep-water environment with dominantly matrix-dominated breccias. The field has confirmed excellent reservoir quality for a transported carbonate reservoir with an average porosity of 15%. Exclusive cores, thin sections, and stable isotope analyses have been used to better define the reservoir properties, lithofacies, and diagenetic process. Several facies have been described from conventional cores and thin sections. Two dominant facies have been identified with different reservoir properties: matrix-dominated and clast-dominated breccias. According to the core analysis, the matrix-dominated breccia facies have better porosity and permeability compared to the clast-dominated breccias. The elevated reservoir properties are interpreted to be controlled by a deeper burial dissolution diagenetic process, which significantly enhances the reservoir quality. Multistage diagenetic evolution in this debris flow carbonate is proven by thin sections, cathodoluminescence petrography along with stable carbon and oxygen isotopes analysis. 87Sr/86Sr isotopes indicate Chattian age, which is consistent with a biostratigraphy analysis. Despite the Ruby Field is comprised of a re-deposited carbonate play, the reservoir could produce gas with no deliverability issues as observed during the production. The Ruby Field is currently the only field producing from a carbonate debris flow play in Indonesia. Given the presence of numerous carbonate platforms in relatively similar geological settings in Indonesia, there are likely to be many carbonate debris flow opportunities yet to be discovered. This poster describes an overlooked play, which could provide opportunities to be chased by explorers.