运用岩心观察、薄片鉴定及物性分析等方法手段,对准噶尔盆地西缘车排子地区侏罗系储层特征进行了系统研究,并结合有效储层物性下限计算,探讨了研究区储层的控制因素,划分了储层类型。研究表明,该区发育颗粒支撑砾岩相、杂基支撑砾岩相、含砾砂岩相、砂岩相、粉砂岩相等五类岩相储层,其中砾岩类储层储集空间不发育,多为特低孔超低渗储层;砂岩类储层储集空间发育,以原生孔隙为主,多为中高孔中高渗储层。通过研究区成岩作用类型和强度的定量分析,共识别出11种成岩相。储层的储集物性主要受岩相控制,而成岩作用则促进了储集物性的分异。结合有效储层物性下限及物性分析,研究区储层可分为3大类:Ⅰ类为(含砾)砂岩相与中等—强溶蚀成岩相组合控制的储层,储集物性最好;Ⅱ类为粉砂岩相与弱胶结弱溶蚀成岩相组合控制的储层,储集物性次之;Ⅲ类为砾岩相或砂岩相与中等—强胶结弱溶蚀成岩相组合控制的储层,该类储层储集物性最差。
We analyzed the characteristics of Jurassic reservoirs in the Chepaizi area in the western Junggar Basin using thin section microscopy,core description and physical property analysis. Combined with the study of petrophysical parameter cutoffs,we summarized the controlling factors of reservoirs,and divided reservoirs among types. The results showed that reservoirs in the study area mainly develop five lithofacies including matrix-supported conglomerate facies,particle-supported conglomerate facies,conglomeratic sandstone facies,sandstone facies and siltstone facies.The conglomerate reservoirs had limited reservoir space with very-low porosity and ultra-low permeability. The sandstone reservoirs develop comparatively more reservoir space,mainly primary pores,and show the characteristics of middle to high porosity and permeability. By the quantitative evaluation of diagenesis,we identified 11 diagenetic facies. The properties of reservoirs are mainly controlled by lithofacies,and diagenesis promoted the differentiation of reservoirs. Combined with petrophysical parameter cutoff and reservoir properties,three reservoir types are identified in this area. TypeⅠreservoirs are the combinations of( conglomeratic) sandstone facies and medium to strong dissolution diagenetic facies,and the reservoir properties are best. Type Ⅱreservoirs are the combinations of siltstone facies and weak cementation,weak dissolution diagenetic facies,and the reservoir properties are poorer than type I. Type Ⅲreservoirs are the combinations of conglomerate or sandstone facies and medium to strong cementation,dissolution diagenetic facies,and the reservoir properties are poorest.