赵凹油田安棚区深层系低渗致密砂岩储层特征

RESERVIOR CHARACTERISTICS OF LOW PERMEABLE SANDSTONES IN DEEP LEVEL FROM ANPENG AREA,ZHAOAO OILFIELD

王振奇 侯国伟 张昌民 张尚锋 樊中海 孙尚如 赵庆 王国鹏 付柘

Wang Zhenqi Hou Guowei Zhang Changmin Zhang Shangfeng Fan Zhonghai Sun Shangru Zhao Qing Wang Guopeng Fu Ze

泌阳凹陷赵凹油田安棚区深层系主要指埋深大于3 000 m的核三下段,属扇三角洲沉积.岩芯描述和常规薄片、铸体薄片、扫描电镜、X-衍射分析及压汞资料研究表明,安棚深层系的岩石类型主要为岩屑砂岩、长石岩屑砂岩和岩屑长石砂岩.快速堆积,颗粒大小混杂,分选差,成分成熟度和结构成熟度低,是导致深层系砂岩低渗的基础条件;砂岩储层以扇三角洲前缘的水道砂和河口坝砂物性最好,席状砂次之;储层孔隙类型以次生溶孔和残余粒间孔为主,孔隙小,具两种孔隙介质,喉道细小且不均匀,孔喉分布状况差,结构复杂,为典型的特低孔特低渗储层;成岩作用,特别是压实作用和晚期碳酸盐胶结充填作用是影响储层微观非均质性和导致储层致密低渗的主要因素.

Anpeng deep strata series are usually buried deeper than 3 000 m,and belong to the lower part of the third member of Hetaoyuan Formation fan delta sedimentary system.The difference of sedimentary environment resulted in serious heterogeneity of the sandstone reservoirs.Core descriptions,conventional thin section,injecting thin sections,SEM observations,X-ray analysis of clay minerals,mercury injection data and pattern analysis of pore structures show that the major rock types are lithic sandstone,feldspathic litharenite and lithic arkose.Also it is found that,in the sandstone,the subaqueous distributary channel sandbodies and the mouth bar sandbodies have the best physical properties.Rapid accumulation,miscellaneous grain size,low maturity of texture and composition are the predetermination condition of low permeability.The main type of pores is the secondary porosity.The reservois are poor in pore throat distribution,complex in structure,small in throat and their evident character is heterogeneity.They are the typical compacted low permeable reservoirs.The diagenesis,especially the compaction and the later carbonate cementation are the key factors affecting the microheterogeneity of the reservoirs and leading the reservoirs to be compacted and low permeable.

10.11743/ogg20010419