East Natuna Basin is a back-arc basin that has big potentiality of hydrocarbon reserves. Ithas potential gas recoverable resources around 46 TCF (IHS Database). The largest field in this basin, Natuna D-Alpha field, had high carbon dioxide (CO2)content problems, around 72% (Dunn P.A, et all 1996). East Natuna Basin has source rocks in coals and carbonaceous shales Gabus, Barat and Arang formations with the Gabus Formation considered the most important with Middle Miocene to Lower Pliocene Terumbu Formation as the primary reservoir. The main seal in the basin is provided by the Pliocene-Quaternary Muda Formation.
The Carbon Capture and Storage (CCS) or Carbon Sequestration is a relatively new concept with the first commercial example was Weyburn Field, Canada in 2003. CCS is a process of capturing waste carbon dioxidefrom large point sources, such as fossil fuel power plants, transporting it to a storage site, and depositing it where it will not enter the atmosphere, normally an underground geological formation. This methodology is one of technologies to reduce gas emission. It will be useful to be applied in field with high CO2 content.
This paper will briefly discuss the potentiality of Terumbu Formation as the CO2 storage in East Natuna Basin. A brief explanation and comparison with the worldwide on-going project Carbonate CO2 storage will be shown based on reservoir properties andprinciple on sedimentology.