惠民凹陷夏口断裂带及附近断块断层封堵机理分析-analysis of sealing mechanism of xiakou fault zone and its adjacent fault blocks in huimin sag.docx

摘要通过地质、测井、岩心化验分析等手段，开展对夏口断裂带及附近断块断层封堵机 理的系统研究，剖析断层封堵性的内在原因，解决断块油气成藏的关键问题，从而能够 开拓找油思路，指导今后的勘探评价部署工作，对于油气勘探开发具有重要的理论意义 和现实意义。在利用断层两盘岩性配置关系对断层封堵性进行定性评价时，如果目的层与泥岩对 接时，断层封闭性好；当砂岩与砂岩对接，且有相同或相近的排驱压力时，断层封闭性 差；当断层两侧接触的砂岩具有不同排驱压力时，断层的封闭程度取决于两盘排驱压力 差 。断层封闭性受断层两盘地层的泥质含量和断面正压力等因素的影响,断面正压力的大 小与断层倾角和断块埋深有关。因此，可根据断层两盘的泥质含量及埋深,评价断层的封 闭能力。夏口断裂带及附近断层主要存在三种封堵模式，即砂泥并置封堵、泥岩涂抹封堵和 碳酸盐胶结充填封堵。根据岩石的排替压力封闭原理,提出了砂泥岩薄互层段中断层封闭 性的定量评价方法。在油源条件充足的情况下，断层的封堵能力体现在油藏高度上，油 藏高度越大，断层封堵能力越好。通过对典型油藏进行剖析，回归出排驱压力与孔隙度、 渗透率之间的关系，由此可根据已知孔隙度或渗透率得出排驱压力，进而利用排驱压力 与油柱高度的关系，估算断层的封闭程度。研究结果表明，夏口断裂带及附近断块断层的封闭性在时空上存在着较大的差异, 并在油气的运聚过程中起着不同的作用；夏口断层控制着运移至缓坡带的油气量,其东段 侧向封闭性较差,可以连接源岩和圈闭形成油气运移的通道；其西段侧向封闭好,阻止油 气继续运移成藏；缓坡带内三、四级断层控制着油气运聚的层位；下一步的勘探目标应 为研究区北部沙四段地层中的断块圈闭。关键词:断层封闭性；泥岩涂抹；排替压力；定量评价AbstractBy geology,log,core analysis ect, we start the system study of fault sealing mecha nism, analyse the inner casue of fault seal oill and gas,solve the key problem of block reservior.By this way,we could develop the mind to find Oil and guide exploration deployment in the futhure.It is siga nifica nt for oill and gas explor ing.The sealing ability of faults is ma inly determined by the displacement pressure cont rast of fault rock against reservoir , while the displacement pressure of fault rock is cont rolled by shale content and dia genet ic grade of fault rock. The shale content of fault rocks depend on theproportion of mudstone thick ness of faulted formation ，and the positive pressure exerted onthe fracture surface determines the dia genet ic grade of fault rock. The positive pressure of ractured surface has relation with the fault dip and buried depth of the fault rock while the displacement pressure of reservoir is cont rolled by the shale content and buried depth of reservoir.Setting the alternation relationship between displacement of different shale content rock and buria l depth.There are three sealing models at Xiakou faulted zone in the Huimin depression ，sandstone and mudstone colloca tion seal，mudstone smearing sea