Oil to Source Rock Correlation of Besuki Area and its Role in Petroleum System of Banyumas Basin

Abstract

Banyumas Basin is a basin that has signs of the presence of hydrocarbons, including oil and gasseep on the surface, which indicates active petroleum systems in the subsurface. A lot of oil and gas seeps werefound in Banyumas Basin, including oil seeps in Cipari and Besuki, while gas seeps were found in Mount Wetan,Karanglewas, and also Cipari. Exploration drilling wells have also been carried out, such as the Jati-1 Well, KarangNangka-1, Karang Gedang-1, Tjipari-1, and Mount Wetan-1, but there still has been no significant evidenceof this basin producing hydrocarbons. The TOC value of the outcrop samples taken in Cipari and Besuki have badvalues, while the crude oil has reflected a severe biodegradation process. Both oil seep samples and one extractbitumen contained high bicadinane (R (resin) annotation) and oleanane indicating both oils and extract to have aninput to Tertiary-sourced oils throughout Southeast Asia. Both oil seep samples do not exhibit similarity with theextract source rock. Based on this negative correlation there may be another source rocks in Banyumas Basin, derivedfrom rocks that are not only from Pemali Formation. The existence of this research is expected to be able toadd geological data, especially hydrocarbon geochemical data in Banyumas Basin, so that it can provide evidenceof the prospect and calculation of reserves contained in this basin, and an understanding of the source rock it self.