Bio-markers based oil to source rock correlation and paleo-environmental interpretation: A case study from Talang Akar Formation, South Sumatra Basin, Indonesia

Abstract

Talang Akar Formation is a proven hydrocarbon source rock in South Sumatra basin. This study used 3 crude oil sample and 6 well-cutting obtained from Talang Akar Formation. Biomarkers analysis has been used to determine the depositional environment of Talang Akar Formation. The techniques utilized include gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) analysis of normal alkanes, isoprenoids, triterpene, and steranes. The most commonly used, pristine (Pr) to phytane (Ph) ratio is a good indicator of the depositional environment. The results in this research show that Pr/Ph ratios range from 5.90-10.08. Pr/Ph indicating abundant terrigenous plant input deposited under oxic to suboxic conditions. The oil/source rock correlation analysis using biomarker data shows that the oils field is correlated with the oils in source rock of Talang Akar Formation. This study concludes that the source rock in Talang Akar Formation was deposited in a transitional (Fluvio-deltaic) to marginal marine environment under oxic conditions.

Evaluation of Hydrocarbon Source Rock Potential and Organic Geochemistry in North Arafura Shelf, Papua (Indonesia)

“…All of the analyses were performed by using geochemical parameters from Batten (1976), Smith (1983, Peters (1986), Peters andCassa (1994), andHunt (1996). Identification of hydrocarbon source was conducted using a plot of Pr/nC 17 against Ph/nC 18 (Peters et al, 2005), plot of hopane/sterane against Pr/Ph ( Syamsuddin et al, 2019), plot of δ 13 C value of saturated fraction against δ 13 C value of aromatic fraction of carbon isotope composition (Sofer, 1984), and C 27-29 steranes ternary diagrams (Huang and Meinschein, 1979).…”