准噶尔盆地南部红雁池断层结构特征与垂向输导油气模式

The structural characteristics and oil-gas vertical migration mode of Hongyanchi fault in Junggar Basin,Xinjiang,China

研究准噶尔盆地南部地区断层的结构特征及对油气垂向输导的影响。基于野外调查、地质与地化资料,精细刻画了断层结构;结合油源对比和油源期次分析,确定了红雁池断层结构与油气垂向输导模式。红雁池断层具有滑动破碎带、主动盘诱导裂缝带、被动盘诱导裂缝带等3个结构单元。其中滑动破碎带由各种断层岩组成,裂缝发育但基本全充填;主动盘诱导裂缝带、被动盘诱导裂缝带内裂缝发育,部分充填,原岩结构保留。断层内曾发生4次较大规模的流体活动,油气主要来自断层下伏的中二叠统源岩,大规模油气运移主要发生在第三次流体活动时期。油气运移前,断层滑动破碎带大部分已封闭,主动盘诱导裂缝带是断层垂向输导油气的优势通道,靠近滑动破碎带处是优势部位,被动盘诱导裂缝带是次要通道。

The characteristics of Hongyanchi fault and its effect on the vertical m igration of oil and gas are studied on the basis of field investigation,analyses of geological and geochem ical data. It shows that the Hongyanchi fault consists of three structural units, including the sliding fracture zone, the active hanging wall induced fracture zone and the passive footwall induced fracture zone. The sliding fracture zone is com posed of all kinds of fault rocks and full of cracks. Fractures are well developed and partially filled in the active and passive wall induced fracture zones, and the original rock structure is unchanged. It shows that four large scale fluid activities occurred in the fault,and oil and gas were m ainly originated from the source rocks of the Middle Perm ian under the fault plane. Large scale oil and gas migration mainly occurred in the third stage of fluid activity. Before oil and gas migration,m ost of the fault sliding fracture zone has been closed. The active fault wall induced fracture zone and the position near the sliding fracture zone are the favorable channel for verticalm igration of oil and gas and the passive fault wall induced fracture zone is only the secondary channel for the vertical m igration of oil and gas.