UNLOCKING MESOZOIC PETROLEUM SYSTEM POTENTIAL OF UNDER EXPLORED SOUTHERN BINTUNI BASIN

摘要

Bintuni Basin had become one of the most attractive basins in Indonesia following the significant discovery of Mesozoic Petroleum System at Tangguh Fields in the 1990s with Middle Jurassic sandstones as the main reservoir. Substantial exploration and appraisal efforts in this basin were conducted with focus area around Tangguh Fields at Bintuni Bay (Northern Bintuni Basin) for decades. It left the Southern Bintuni Basin remains under explored for Mesozoic Petroleum System potential. The success story of the Tangguh Gas Development had triggered extensive New Ventures and Exploration activities in the Eastern Indonesia region since around 2005, including in the Bintuni Basin itself and the nearby areas, such as Semai and Cendrawasih Bay. After rigorous studies and assessment of Eastern Indonesia region, Chevron decided to carry out Joint Studies to acquire Exploration Blocks in Bintuni Basin. Subsequently, West Papua I PSC and West Papua III PSC were awarded to Chevron on November 2008. Comprehending that this region is very complex geologically and operationally, Chevron then formed partnership with BP and MOECO to plan and execute Exploration works in these two PSCs. To validate old interpretation and to better understand regional geology of Southern Bintuni Basin, Chevron and its partners conducted several studies, including biostratigraphy study to revisit wells that were drilled during 1970s in this area, which mostly targeted Miocene Carbonates (equivalent to Kais FM in Salawati Basin) as major reservoir. Nonetheless, there were also some wells in Southern Bintuni Basin that were drilled deep enough to penetrate Mesozoic Section, including ASF-1X. Final well report of ASF-1X well led most of geoscientist to interpret that Middle Jurassic section was eroded in this area, while our newest biostratigraphy work has suggested otherwise. As part of exploration commitments, Chevron and our partners also acquired 2D seismic data during 2011-2012 in these two PSCs with total length more 1,100 km. This new seismic dataset was the key element to yield better understanding of the petroleum system in the area. These new seismic lines have enabled us in identifying different structural styles and different play types in the Southern Bintuni Basin. Based on these newly acquired seismic data and regional studies conducted by Chevron and its partners, Mesozoic Petroleum System in the Southern Bintuni Basin is still a promising play for future exploration in Eastern Indonesia. However, further Exploration works will be required to prove the existence of working Petroleum System in the Southern Bintuni Basin.