白豹地区长4+5储层孔隙结构特征

Porous-structure Features of Chang 4+5 Member, Baibao Area

根据铸体薄片、扫描电镜和压汞等资料,对白豹地区长4+5储层孔隙结构特征进行了研究。结果表明:白豹地区长4+5储层的岩石类型以长石砂岩和岩屑长石砂岩为主;孔隙类型以残余原生粒间孔为主;渗流通道多为细、微细喉道;排驱压力高,退汞效率低,具有低孔、低渗储层的特征。储层孔喉分选系数与均值系数均较大,储层非均质性较强。综合物性数据与压汞参数将研究区储层的微观孔隙结构划分为4类,其中第Ⅰ、Ⅱ、Ⅲ类为有效储层,第Ⅳ类为无效储层。

In the Chang 4+5 Member of Baibao area, the porous structure was studied on the basis of some data from casting thin- section, SEM, and mercury injection. Results show that(1)this reservoir is mainly composed of feldspathic sandstone and lithic arkose;(2)its porous types are dominated by residually primary intergranular pore;(3)the seepage channels include fine to finer throat;(4)the displacement pressure is high and mercury-ejection efficiency is low;(5)it is characterized by low permeability and porosity, and strong heterogeneity; and(6)the coefficients of porethroat sorting and mean value are big. According to physical property and mercury-injection parameters, the porous structure can be divided into four types at a micro level, among which the I-, II-,and III-type reservoirs are effective ones, and the IV-type reservoir belongs to nonreservoir, respectively.rddrmKHHduBAdlo