定边地区侏罗系延安组延9储层成岩作用特征

Diagenesis of Yan 9 reservoir of Yan'an Formation of the Jurassic in Dingbian area

通过岩石薄片、铸体薄片、物性、高压压汞、阴极发光、扫描电镜及X射线衍射等测试手段,对定边地区延9砂岩储层成岩作用进行研究。结果表明,研究区延9储层经历了压实作用、胶结作用及溶蚀作用,压实作用、伊利石胶结及碳酸盐胶结破坏原生孔隙,使储层物性变差;高岭石对储层物性的影响具有双重性;溶蚀作用产生较多的次生孔隙,有利于改善储层物性。依据粘土矿物组合及自生矿物分布,认为研究区延9砂岩成岩演化阶段进入了中成岩阶段A期。研究为储层综合评价及有利区优选提供了地质依据。

The physical properties,high pressure mercury,cast section,Cathode luminescence,SEM and X-ray analysis samples are introduced in this experiment to study the diagenesis of Yan 9 reservoir. The results show that the Yan 9 reservoir experienced compaction,cementation and dissolution,compaction,the cementation of illite and carbonate cementation destroying the primary pore,which make reservoir properties worse; the effect of kaolinite on physical property of reservoir is a dual; dissolution produces more secondary porosity that will help to improve reservoir property. Based on a combination of clay minerals and authigenic mineral distribution,we can draw a conclusion that the Yan 9 sandstone diagenetic evolution stage is in A period of the middle diagenetic stage. This study provides geological basis for the comprehensive evaluation and optimization of favorable reservoir.