鄂尔多斯盆地吴起曾岔地区长6油层组储层特征及控制因素分析

Analysis on Controlling Factors and Characteristics of Sandstone Reservoir of Chang 6 in Zengcha Area in Wuqi Oilfield,Ordos Basin

通过对鄂尔多斯盆地吴起曾岔地区延长组长6储层的铸体薄片、电镜扫描、压汞等资料的综合研究,分析了储层的岩石学、孔隙结构及物性等特征,并剖析物性优劣的控制因素。研究表明,以水下分流河道为储集主体的长6储层砂岩主要为长石砂岩、岩屑长石砂岩,填隙物以绿泥石和(铁)方解石为主,储集空间以残余粒间孔和长石溶孔为主,喉道为小孔细喉型,物性较差,为低孔特低渗储层。控制储层物性的主要因素有:源区母岩、沉积环境和成岩作用(压实、胶结和溶蚀)等。

Based the cast thin section,scanning electron microscopy,mercury penetration and physical property analyses,lithology characteristics,microscopic structure,physical property of the Chang 6 reservoir in in Zengcha area in Wuqi Oilfield,Ordos Basin,were studied,and the controlling factors were analyzed.Research shows that the distributary channels subfacies are the main reservoir,and arkose and lithic arkose sandatone are most common.The main interstitial materials are chlorite and calcite(ferrocalcite).Residual intergranular pore and feldspar dissolved pore are the dominant reservoir spaces.The Chang 6 reservoir has a low porosity and ultra-low permeability with small pore and fine throat and poor physical property.The controlling factors are:parent rocks in the source area,sedimentary environme,diagenesis,etc.