Publications

Supat is an oil field in Corridor Block in the South Sumatra Basin. This field has two main oil-bearing reservoirs, named the Talang Akar Formation (TAF) and the K-limestone Formation (KLS). These reservoirs are not in pressure communication. TAF Formation has been produced for 28 years while KLS was assessed and proved as an oil reservoir in 2014 and 2015. However, KLS did not have continuous production due to flow assurance problem. This paper discusses the geochemical analyses performed to characterize oil properties from both formations (TAF and KLS). The analysis that consists of SARA (saturated, aromatic, resin, and asphaltene) compositions, API gravity, pour point, WAT (wax appearance temperature) and WDT (wax disappearance temperature) were performed on oil samples. High Temperature Gas Chromatography and Mass Spectrometry (HTGC-MS) was also conducted on the saturated and aromatic fractions of the oils for biomarker analysis. Based on the physical oil characteristic analysis, the oil produced from TAF and KLS is different in term of SARA, API gravity, pour point, WAT and WDT. The analysis describes that producing oil from TAF has a propensity to form wax whereas the producing oil from KLS tend to form asphaltene. Nevertheless, the results of Gas Chromatography and Mass Spectrometry analysis indicate that the oils from both formations have same source progenitor which is terrestrially derived higher land plant (D/E Type organo-facies) source rock. This source rock was deposited in fluvio-deltaic or transitional system. It is then concluded that the variation in oil composition occurred due to alteration during and post migration and accumulation.