定边油田樊学油区延安组延9储层特征研究

樊学油区位于鄂尔多斯盆地伊陕斜坡带的西部边缘,中侏罗世延安组延9层位分为延91和延92两个砂层组。研究区延安组储层岩性为中粒的灰白色长石石英砂岩、岩屑长石砂岩,岩屑成份以变质岩为主,主要粒径0.25mm～0.65mm,分选好,颗粒呈次圆-次棱状,胶结类型为次生-孔隙,以硅质胶结为主。填隙物含量一般介于6.8～15%之间,主要为以高岭石为主;胶结类型以孔隙式为主,属中-高孔隙度、中渗透率储层,储层物性较好。孔隙类型以剩余粒间孔和溶蚀孔为主。孔隙结构以大孔中喉与中孔、中小喉为主。成岩作用主要有压实作用、胶结作用、压溶作用、溶解作用及交代作用。压实作用中刚性颗粒发生破裂而产生的微裂缝,对低渗储层储集性能的改善具有积极的意义。

Fan xue oil zone is in the western edge of slope Iraq Shaanxi,Ordos Basin,the Middle Jurassic Luo Shi Yan'an Formation yan 9 extended into the yan 91and yan 92two sand groups.Yan'an Formation lithology is for the medium-grained gray feldspar quartz sandstone,lithic arkose,lithic composition dominated by the metamorphic rocks,the main particle size is about 0.25mm to 0.65mm,well sorted,the particles were round-sub-prismatic cement type secondary-porosity,mainly siliceous cement.Interstitial material content is general-ly between 6.8 to 15%,mainly dominated by kaolinite;cement type is pore type,and belongs to middle-high porosity,permeability reservoir,good reservoir properties.Pore types of the remaining grain is intergranular pores and solution pores.Pore structure with a large hole in the throat and holes,small and medium-sized jets.The diagenesis main compaction,cementation,pressure solution,dissolution,and metasomatism.Com-paction of rigid particles rupture and produce micro-cracks,the improvement of the low permeability of the reservoir performance has a positive meaning.