Application of hydrocarbon-generating chemical kinetics in the Puguang gas field,NE Sichuan Basin

The Puguang gas field is a gas field with the largest scale,buried depths and oil-gas reserves in the Sichuan Basin.Based on the relations of the contribution of different source rocks,the key hydrocarbon-generating period and the tectonic evolution,the model of hydrocarbon-generating chemical kinetics was established and kinetics parameters were calibrated.The hydrocarbon-generating and oil-cracking processes were described quantitatively using the data of the source rock parameters,the basin burial and geothermal histories.The chief source rock is the Lower Silurian mudstone in the Puguang area,the chief kerogen-formed oil period is from the late Early Permian to the late Early Triassic(286-240Ma),the chief kerogen-formed gas period is in the Middle Triassic(240-230Ma),the main origin of natural gas is the late-stage oil-cracking gas,and the chief period of oil-cracking is Early Cretaceous(144-97.5Ma).The formed pattern of the gas field is of the multi-stage hydrocarbon accumulation,the transformation from oil to gas,and the late-stage finalization.