Publications

Exploration is being carried out intensively in eastern Indonesia, including the Timor Island area. Timor Island is located in an area near several commercial hydrocarbon accumulations in the Australian continental margin, such as the Kakatua oil field, the Bayu Undan gas and condensate field in the Timor Gap, and the Abadi gas field in the Aru Sea. These discoveries have encouraged exploration efforts on the Timor Island. Several new wells have recently been drilled in Timor Leste, which lies in the north east section of Timor Island. This research is conducted to determine the potential of source rock and correlate oil to source rock in the West Timor area, especially the north east part. An oil seepage was found in Wemasa Beach, Kobalima Sub-District, Malaka,East Nusa Tenggara.. This seepage is proof that the petroleum system in this area is working. Biomarker analysis on the oil sample was carried out using Gas Chromatography Mass Spectrometry. Ten outcrop samples from six formations were collected and analyzed the Total Organic Carbon, vitrinite reflectance, and kerogen type. Seven of ten rock samples were also extracted and analyzed using GCMS to determine the biomarker composition. From the analysis of the samples, the TOC value is between 0.46-0.96 wt% which categorized as poor to fair organic carbon, while a sample determined as Kapan papery black shale (C8-02A-03) has an excellent TOC of 43.7 wt%. The samples maturity is in the range of peak to late mature based on vitrinite reflectance analysis (0.70–1.30 % Ro). From Thermal Alteration Scale, the the Kapan Shale is immature as it is the Mid-Pliocene Noele. Based on kerogen typing analysis, gas-prone kerogen (Type III) and inert kerogen (Type IV) are dominated by 9 samples. The Kapan Shale is dominated by amorphous fluorescence (76%) and characterized as Type I/II kerogen. From the biomarker fingerprinting, the Wemasa oil seep is more likely a Late Triassic-Early Jurassic Aitutu.