3D Petroleum System Modeling Study has been developed by using the Eni E&P Division internal package (e-simba?) in order to evaluate the petroleum potential of the Pearl River Mouth Basin, in the South China Sea. Pearl River Mouth Basin is a Mesozoic-Cenozoic passive margin rift basin oriented NE-SW and parallel to the continental shelf. Within the Basin two main source rocks are recognised in the syn-rift succession: the organic levels of the Enping Formation, Oligocene in age and mainly terrestrial, and those of the Wenchang/Enping Formation, Oligocene/Eocene in age and mainly lacustrine. Based on geochemical analysis of well data, the Enping source rock is modelled by using terrestrial kerogen type, TOC 1%, HI 250 mgHC/gTOC, 100 m of thickness and kinetics from analogue of Mahakam Delta. The Wenchang/Enping source rock is modelled by using lacustrine kerogen type, TOC 4%, HI 600 mgHC/gTOC, 100 m of thickness and kinetics from analogue of Green River. Thermal data coming from wells and confirmed by literature suggest an average geothermal gradient of 35°C/km. The heat flow values at Present time match with well data. The creation of heat flow map was done by using a geostatistical approach, kriging with external drift method - software ISATIS, and by considering the correlation between the calibrated heat flow value at single well and the geological trend. Over the study area the heat flow trend correlates both with seismic and magnetic basement. The results of thermal model integrated with geochemical well data (CO2 and gas maturity) show that the heating better correlates with seismic basement and allow to define the positioning of the organic matter level. A terrestrial source rock can be located in the shallower part of the Eocene/Oligocene sequence while a lacustrine one can be localised in the depocentral area at the base of the same sequence.
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