Characterisation of crude oils and gas in blocks 05-2 and 05-3 - Nam Con Son basin using biomarkers, gas chromatography and carbon isotope analysis

Tóm tắt

Research on petroleum systems is the basis for evaluating the potential of a sedimentary basin during exploration and exploitation processes. In this, results from analysed samples are very useful. In the Nam Con Son basin offshore Vietnam, several oil and gas fields have been found such as Dai Hung, Thanh Long, Bo Cau, Nguyet Thach, Moc Tinh, Hai Thach, Lan Tay, Lan Do, etc. However, the origin of organic matter and the distribution of crude oils in Nam Con Son basin still pose difficult problems for petroleum geologists. Certain questions remain to be answered, such as the origin and transformation level of organic matter, depositional conditions, rate of sedimentation or even why geologists have not discovered oil accumulations leading to gas being found more than oil. In this paper, the authors use advanced analysis technology and combine effective analysis parameters to evaluate and classify the origin of oil and gas in Blocks 05-2 and 05-3. According to the results of GC, GCMS and carbon-13 isotope analysis, crude oil at the Nguyet Thach well is believed to be generated from a low maturity source rock containing lacustrine organic matter.