应用岩石薄片、扫描电镜、恒速压汞等实验资料,对南缘中段东沟组储层微观孔隙结构特征进行分析,东沟组储层内发育原生粒间孔、剩余粒间孔及少量粒内溶孔和微裂缝,喉道类型主要为缩颈型喉道,其次为孔隙缩小型和片状型喉道,每个背斜的储层孔喉类型、分选性及连通性都不尽相同.在压汞资料的基础上,运用因子分析优选出分选系数(Sp)、中值半径(R50)、排驱压力(Pd)等8个最能反映原始孔隙结构信息的参数,采用二阶聚类方法将研究区储层孔隙结构分为了I、Ⅱ、Ⅲ类,并对其进行了评价,最后用压汞曲线及Bayes判别法对此分类方法进行了验证,样品分类结果的正确率达到99.1％.分类结果表明:I类孔隙为大孔粗喉型、Ⅱ类为中孔中-细喉型、Ⅲ类为小孔细喉型;I、Ⅱ类孔隙结构的储层为研究区的有利储层,该分类研究为油田下一步剩余油的开发提供了有利的依据.%Experimental data of casting thin section,SEM and mercury injection test are applied to analyze micro pore structures of K2d reservoir in the middle zone of southern Junggar Basin.The main types of K2d reservoir pores are primary intergranular and residual intergranular ones,with a small number of intragranular dissolved pores and micro-cracks.The principal throat is necking throat.Pore-shrinking and sheet throats are the next two kinds of throats.Types of reservoir pore throats,sorting and connectivity of each anticline are different.Based on mercury injection tests,the author choose 8 parameters including standard deviation (Sp),median pore throat radius (R50),displacement pressure (Pd),et al by factor analysis,which mostly reflect the information about the original pore structure,and apply two-step cluster method to classify pore structures to 3 types:Ⅰ,Ⅱ,Ⅲ.Finally,the Bayes discriminant analysis and capillary pressure curves prove that the correct discrimination rate of clustering results can reach 99.1％.This result indicates that type Ⅰ is large pore and coarse throat while type Ⅱ and Ⅲ are separately medium pore mid-find throat and small pore find throat.Ⅰ and Ⅱ pore structures are mostly favored reservoirs in studying.The classification provides a favorable foundation for a further exploitation of the remaining oil.
展开▼
