涠西南凹陷11-7构造区流沙港组中深层有效储层下限厘定

The physical property lower limit of medium-deep effective clastic reservoirs in Liushagang Formation,11-7 district of Weixinan Depression

为明确涠西南凹陷11-7构造区流沙港组中深层碎屑岩有效储层物性下限,基于物性、生产测试、试油、压汞及测井综合地质解释等资料,利用分布函数曲线法、动态生产测试法、试油法、束缚水饱和度法及最小有效孔喉半径法,进行有效储层下限的厘定,并以物性差值为对比参数,结合沉积相、砂体厚度、成岩演化、岩石成分和地层压力进行控制因素分析。结果表明:该区有效储层主要受沉积相和砂体厚度因素控制,辫状河三角洲水下分流河道微相储层最好,重力流有效储层发育程度差;次要因素为成岩阶段,相同成岩期内粗粒岩性较中细粒储层物性差值分异幅度大;岩石成分刚性组分含量高,物性差值高,次生孔隙带长石含量高,物性差值高。该区局部超压作用与储层有效性正相关,但影响作用较小。

On the basis of the comprehensive application of physical properties,production test,oil testing data,mercury injection data and well log geological interpretation,and by applying distribution function curve method,production test method,oil testing method,irreducible water saturation method,and the lowest effective pore throat radius method,we define the physical property lower limit.Also,we analyzed the controlling factors of the effective reservoir from sedimentary facies,sand thickness,diagenetic evolution,rock components and formation pressure.Our results demonstrate that the main controlling factors are sedimentary facies and sand thickness.Distributary channel facies of braided delta are most effective reservoir development areas,while the least effective reservoir development area is gravity flow environment.Porosity and permeability difference increased with the increasing of particle size in the same diagenetic stage.Also,the higher content of quartz and feldspar,the higher porosity and permeability difference and higher feldspar content,the higher porosity and permeability difference in secondary pore belt.There was positive correlation between overpressure and reservoir effectiveness,but overpressure phenomenon is not developed in the Liushagang Formation and the overall impact is less important.