基于孔隙度分析的断裂连通路径识别方法

Identification method of fault connectivity path based on porosity analysis

塔里木盆地顺托果勒区域发育了一种特殊的断控缝洞类型油气藏,目前,对于断裂破碎带内部非均质性及连通渗流能力的认识还不够清晰,制约了油气田储量精细动用以及注采井网构建.研究区域内地层经历了多期断层改造活动,断裂较为发育、空间结构复杂,并且是洞穴储集体间连通的主要通道,因此对于断裂连通强弱、连通路径的表征和分析是研究的重点.本文首先验证了工区内利用孔隙度表征渗流能力的可行性,将孔隙度赋值于断裂面之上,通过分析断裂沿不同走向孔隙度特征判断最优连通走向;以Dijkstra路径搜索算法为基础,以断裂面上指定点位置为起点,自动搜索孔隙空间最大化时的连通路径,并对连通路径上孔隙度分布特征进行分析,结合生产动态数据验证,可以实现井组内连通路径的有效表征和预测,为油气田井组注采开发、井网设计等提供参考依据.

A special type of fault-controlled fracture-cavity hydrocarbon reservoir is developed in Shuntoguole low uplift area of Tarim Basin.The heterogeneity and seepage capacity within the fracture zone are not clear,which affects the fine reserve production and injection-production well pattern construction in oil and gas field.The targeted layers in the study area has experience multiple tectonic movements,resulting in highly developed faults with complex spatial structures.In addition,the fault is the essential connectivity path between cavity reservoirs.Therefore,the analysis of the fault connectivity capacity and the connectivity path are the focus of the research.In this paper,the feasibility of seepage capacity characterization by porosity is verified in the work area.By assigning porosity to the fault surface,we determine the optimal connectivity trend by analyzing the porosity characteristics along different strike of the fault.Based on Dijkstra algorithm,the connectivity path with maximum pore space is automatically searched starting from the specified point on the fault surface.As well,the porosity distribution characteristics on the connectivity path are also well analyzed.Combined with the dynamic production data verification,the prediction and quantitative characterization of the connectivity path in the well group can be realized.The method provides reference basis for design and development of well group injection and production in oil and gas field.