不整合结构对地层油气藏形成的控制作用研究

不整合不仅仅是一个“面”,更是一个“体”,其本身具有较独特的微观组构,即具有“空间结构”属性.通过大量的岩心观察、野外踏勘及测井资料对比解释,纵向上提出不整合结构体的概念,并将其划分为三层结构:结构体上层、结构体中层及结构体下层,其中结构体上层与下层构成储集体,结构体中层形成封盖层,且封盖强度随埋深加大而增加.地层油气...

Controls of Unconformity on the Formation of Stratigraphic Reservoirs

The unconformity is not only a recorder of tectonic movement and eustatic fluctuation,but also an indicator of the damage of the pre-sedimentary rocks.The heterogeneous weathering during sea(lake)-level fall and transgressive deposit during sea(lake)-level rise can form vertical structure of unconformity.So the unconformity is not a surface,but a body.The structural body of unconformity was put forward through plenty of core observation,outcrop survey,and logging.The structural body in section can be divided into the upper layer with good primary porosity,the middle layer with compactness and ductility which can be capping rock with sealing strength increases with depth,and the lower layer with good secondary porosity due to weathering and leaching.The unconformities consist of the boundaries and sealing factors of stratigraphic reservoirs.So stratigraphic reservoir can be divided into stratigraphic onlap reservoir which is located above the unconformity surface and stratigraphic truncation reservoir under the unconformity surface,and then divided into eleven sub-types according to the types of unconformity.The key factors controlled the formation and distribution of stratigraphic the reservoirs are onlap line,truncation line,and structural body of unconformity,as suggested by the analysis of the typical stratigraphic reservoirs in the Junggar basin and Bohai Gulf basin