Publications

The role of coal as petroleum source rock has become subject many discussions. Despite the fact that some coals have been found to hold significant petroleum potential, the constraint to expel the oil remains a challenge. Petrographic and geochemichal study have been conducted on low rank coals from Muara Enim Formation in South Sumatra Basin Indonesia to study maceral analysis rock eval pyrolysis regarding the phenomenon.The coal have mean random huminite reflectance between 0.35-0.52% and huminite (34.6-94.6%). Less abundant are liptinite (4.0-61.4%) and inertinite (0.2-43.9%). Minerals are found only in small amounts (0-2 %), mostly as iron sulphide. In the liptinite rich coals, the secondary liptinite maceral, exsudatinite, occurs as pores or fractures fillings. Its presence is an evidence of the ability of those coals to expel liquid hydrocarbons.Based on rock eval pyrolysis parameters, the studied coal have a very good potential to generate hydrocarbons and almost all of posses high Hydrocarbon Index. Samples with high liptinite content also indicate high Hydrogen Index values more than 300 HI mg HC/g TOC.Those indicate that the studied coals can generate not only gas but also oil. However from the Bitumen Index - Tmax relationship, it can be seen that many of them are almost passing the threshold to generate oil. It is also reasonable that the threshold of the oil expulsion is also not yet reached based on Quality Index - Tmax relationship since the temperature is still low. It is clearly indicated that temperature (ie. maturity) has a significant role to initiate the expulsion of oil.Keywords: petroleum potential, low rank coal, South Sumatra Basin