川中磨溪—龙女寺构造带嘉陵江组天然气成藏机理研究

川中地区磨溪—龙女寺构造带下三叠统嘉陵江组天然气的成藏机理一直是一个悬而未解的问题。鉴于前人研究确认嘉陵江组天然气来源于深层二叠系烃源岩,该文主要利用磷灰石裂变径迹与盆地模拟相结合的技术对区内二叠系烃源岩的热史进行了恢复,对其成熟度、古流体压力演化进行了研究,进而对运移通道的形成及天然气成藏过程进行了综合分析,并建立了磨溪-龙女寺构造带嘉陵江组天然气的成藏模式,总结其成藏规律为:高压驱动、裂缝输导、流体垂向运移、膏盖油裂解气成藏。 

The study of accumulation mechanism of natural gas in Jialingjiang Formation, Moxi-Longnüsi area in the middle of Sichuan Basin

The accumulation mechanism of natural gas is still an unsolved problem in the Lower Triassic Jialingjiang Formation of Moxi-Longnüsi area in the middle of Sichuan Basin.The former researcheres considerates that the natural gas of Jialingjiang comes from the underlay Permian source rocks, and this paper mainly rebuilds the maturity history and thermal history of the Permian source rocks in the study area, by combining technologies of apatite fission tack and basinmodelling. Based on the researches mentioned aboved, the paper analyzed the fluid pressure evolution and the formation process of migration pathway, and the accumulation process of natural gas. The paper establish the accumulation model of natural gas of Moxi(u)Longnüsi structural area, and summarizes the following hydrocarbon accumulation: fluid drive with high pressure, conduction by fracture, vertical migration of fluid, oil cracking to gas accumulation sealed by gypsum layers.