CO2对东海盆地丽水凹陷丽水36-1气田成藏的影响OA北大核心CSTPCD

A detailed analysis was conducted on Lishui 36-1 gas field in Lishui west sub-sag by combining macroscopic geology and mi-croscopic geochemistry,revealing the rules of hydrocarbon accumulation in Lishui west sub-sag.The research results indicate that:(1)The Lingfeng Formation in Lishui west sub-sag is generally characterized by overpressure,which can be vertically divided into three zones:overpressure sealed box,troposphere,and deep fluid retention layer.(2)The obvious layered structure in the vertical direction leads to three stages of hydrocarbon charging in the structural zone,and there is a good corresponding relationship between the two:the homogenization temperature distribution of inclusions within the bottom overpressure closed box and the top fluid retention layer is a normal filling phenomenon,while the homogenization temperature in the middle troposphere shows the characteristic of episodic filling.(3)The Lishui 36-1 structural belt has a hydrocarbon accumulation mode of overpressure capping and abnormal thermal fluid break-through transformation.In the early stage,hydrocarbon was sealed under the overpressure zone of Lingfeng Formation.In the later stage,due to the vigorous activity of mantle-derived magma,the primary reservoir carried by mantle-derived CO2 migrated upward and accumu-lated under the action of the regional cap layer of Mingyuefeng Formation to form the present Lishui 36-1 gas field.