生烃化学动力学在川东北普光气田的应用

普光气田是四川盆地近期发现的规模最大、埋藏最深、资源丰度最高的气田。通过认识普光气田各个烃源岩层的贡献量、生烃关键期与构造演化的关系、油气成藏具体模式等，建立生烃化学动力学模型、标定参数，结合地区烃源岩参数和地史、热史资料，定量描述该地区的生烃过程及油裂解成气过程。认为：普光地区的主力烃源岩为下志留统泥岩；主要干酪根生油期为早二叠世末到早三叠世末期（距今286Ma至240Ma）；主要干酪根生气期为中三叠世（距今240Ma至230Ma）；主要气源是原油后期热裂解气，原油裂解成气的时间比较晚，主要油裂解成气期为早白垩世（距今144Ma至97．5Ma），从而决定了普光气田的成藏模式为“多期成藏，油气转化，晚期定位”。图2表3参33

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.