张家滩地区长6油层组储层对致密油富集的控制作用

Control effect of reservoirs on tight oil distribution-a case study ofChang 6 oil layer group in Zhangjiatan area of Ordos Basin

利用岩性、物性、高压压汞数据以及铸体薄片、扫描电镜资料并结合测井、试油和试采数据,分析张家滩地区长6油层组储层对致密油富集的控制作用。结果表明:长6储层含油岩性为细砂岩,粉砂岩不含油;油层厚度与砂体厚度呈现正相关关系,平面上集中分布于中西部和南部地区;孔隙结构主要分为两类:I类为细孔微细喉,以油浸、油斑级为主,Ⅱ类为细-微孔、微细喉-微喉,以油迹和荧光级别为主;各种成岩作用和沉积环境导致较强的储层非均质性,控制了石油的差异富集;层内非均质性形成相对高孔高渗砂体并控制致密油的聚集部位,平面非均质性导致油层厚度大的区域主要分布在砂体厚度大且稳定的区域。

Based on lithology,physical properties,high pressure mercury injection data,casting sheet,scanning electron microscopy data,combined with well logging,oil test and production test data,the control effect of reservoir on Chang 6 tight oil distribution was analyzed.The results show that the oil-bearing lithology of Chang 6 reservoir in Zhangjiatan is fine sandstone,while the siltstone does not contain oil.There is a positive correlation between the thickness of oil layers and the thickness of sand bodies,which is concentrated in the central,western,and southern regions on a plane.The pore structure is mainly divided into two categories,with Class I being fine pore and micro throat,dominated by oil leaching and oil spot levels,Class II being fine-microporous and microfine throat-microthroat,dominated by oil traces and fluorescent.Various diagenetic processes and sedimentary environments result in strong reservoir heterogeneity,controlling the differential enrichment of oil.Heterogeneity within the layer forms relatively high porosity and high permeability sand bodies and controls the accumulation of tight oil.While planar heterogeneity results in areas with large oil layer thickness mainly distributed in areas with large and stable sand body thickness.