济阳坳陷花沟CO2气藏形成与高青断裂活动性关系分析

利用三维地震资料,对济阳坳陷花沟CO2气藏区高青断裂走向上不同区段的活动性进行了分析，指出：花沟CO2气藏所对应的高青断裂区段,在馆陶组—明化镇组沉积时期活动性强，而气藏的东、西两侧,馆陶组—明化镇组沉积时期断裂基本上不活动；花沟CO2气藏与馆陶组—明化镇组沉积时期高青断裂活动性强的区段在平面上有着良好的对应关系；花沟CO₂气藏的运聚过程分为2个阶段，在第1阶段，幔源岩浆成因的CO₂、N₂和He等气体进入高青断裂后,在浮力或压差作用下向断裂顶端运移,并发生重力分异，由于断裂顶端封闭、两侧封堵,CO₂、N₂和He等气体在高青断裂中实现了一定程度的聚集，而在第2阶段，当CO2、N2和He等气体在断裂中聚集到一定程度,便在压力驱动下向断裂两侧砂岩储层运移,并在其中聚集成藏。认为气源断裂走向上活动性的差异决定着CO₂气藏的平面分布位置,断裂活动性强的区段所对应的储层是CO₂气成藏的有利场所。 

Relationships between Different Strike Activities of Gaoqing Fault andHuagou Gas Reservoirs Accumulation, Jiyang Depression

The activities in different sections of the Gaoqing fault in the Huagou gas field were analyzed using 3D seismic data. The activities of the fault segment associated with the Huagou gas field were strong during the Guantao|Minghuazhen period, while the activities on east and west sides of the gas field were weak at that time. The Huagou gas field is well corresponding to the strong activity segment of the Gaoqing fault on the plane. The process of gas migration in the Huagou reservoir is divided into two phases：(1)After mantle|derived magmatogenetic gas including CO2, N2, and He entered the Gaoqing fault, the gas migrated to the top of the fault by the action of buoyancy or pressure, then the gravitative differentiation occurred. For the top of the fault is closed and both sides of fault is sealed, the gas assembled to some degree in the Gaoqing fault；(2)When gas was accumulated at a large scale in the Gaoqing fault, the gas migrated towards the reservoirs along the two sides of the fault and was accumulated in sandstone. The different activities of gas source fault on strike directions decide the distribution of the carbon dioxide gas, the reservoir bed homologous to the strong activity segment of fault are favorable for the carbon dioxide accumulation