Jabung Block, Jambi Sub-Basin, South Sumatra Basin is a part of PetroChina International Jabung, Ltd. Operation area, located at 103000’-104000’E and 103’-1017’S. Geochemical analyses give information needed in determining richness, type, and maturity of source rock. In this research, geochemical data samples that represented some lithological beds, such as Gumai, Upper Talang Akar, and Lower Talang Akar Formations are analyzed from 7 wells in a case study area, Jabung Block, Jambi Sub-Basin, South Sumatra Basin, as well as oil samples from 23 wells.
Richness analyses of organic material showed that Upper and Lower Talang Akar Formations are lithological beds that fulfill the source rock requirement, with fair to very good organic material (TOC>2%). These formations have ability to produce oil and gas with kerogen type II/III. These formations also have reached maturity stage until oil window stage that was represented by some wells. Organic material origin analysis using GC and GC-MS showed that Upper and Lower Talang Akar Formations are deposited in the suboxic environment with mixed organic material of algal and land plant, in transitional environment.
Geochemical analyses show that the source rocks from Lower Talang Akar and Upper Talang Akar Formations have positive correlation with oil samples. The source rocks and oil samples composed of a mixture of algae and land plants, but the oil to source rocks correlation is judged to be “not too sharp” due to influence of Jabung Block palaeogeography at the time of source rock deposition in the study area.
Authors : Dian Larasati, Eddy A Subroto, Hendra Niko Saputra, Beiruny Syam