2D basin modelling as for hydrocarbon charging model (charge access), tangguh field, Bintuni Basin, papua

Bintuni Basin is a foreland basin located in the Bird’s Head of Papua. There were three fields observed in this study, namely Alpha, Beta and Charlie. The subsurface data indicated a mismatch of the order of hydrocarbon maturity in the three fields. This study aimed to explain the causes of incompatibility of the order of field maturity with the concept of generation-migration. The methods which were used in this study were 2D field-scale basin modelling on two seismic lines for subsurface observation, then calibrated to several geochemistry evaluations. Based on the results of source rock analysis, Bintuni Basin has two source rocks, Aifam group and Kembelangan Bawah Group, both of them are gas prone. The accumulated hydrocarbons in the Alpha field leaks into shallower sedimentary layers and do not migrate laterally due to the low clay factor and the distant trap height. The existence of lateral migration is caused by a sloping trap height. From the result of the research, it can be concluded that each field are filled by different charge focus from different migration route. Therefore, there is no correlation between three fields, including the maturity of the hydrocarbon accumulated, other than generated from same source rocks.