摘要
综合薄片鉴定、铸体薄片、扫描电镜、X衍射全岩分析、压汞等方法,系统研究鄂尔多斯盆地枣园安塞延长组长8致密砂岩储层的岩石学矿物学特征、孔隙结构特征、物性以及成岩作用的差异性对储层的影响等。研究发现,其储层岩性主要为细粒长石砂岩,分选较好—中等,胶结物含量较高,杂基较少,结构成熟度较高,成分成熟度较低,孔隙度平均值为7.94%,渗透率平均值为0.63×10-3μm2;孔隙类型主要为残余粒间孔,长石溶蚀孔、铸模孔等次之,组合类型为残余粒间孔长石、岩屑溶蚀孔微孔型,为微—细喉道,有少量的中喉道,为低孔、特超低渗储层;压实、胶结、溶蚀、交代等成岩作用是导致研究区长8储层孔隙结构等差异性的关键因素,压实、胶结作用是导致储层孔隙结构破坏、储层致密化的主要原因,压实作用使孔隙减少率平均在16.61%,胶结作用使孔隙度损失平均在18.28%,溶蚀作用对储层具有改造作用,但效果有限。
Comprehensive methods such as thin section identification,casting thin section,scanning electron microscope,X-ray diffraction whole-rock analysis,mercury intrusion,etc.,systematically studied the petrological and mineralogical characteristics and pores of the Chang 8 tight sandstone reservoir of the Yanchang Formation in the Zaoyuan-Ansai research area in the Ordos Basin.The impact of structural characteristics,physical properties,and diagenesis differences on the reservoir,etc.The conclusions are as follows:①Reservoir lithology is mainly fine-grained feldspar sandstone,sorted well-medium,with high cement content,less impurities,high structural maturity,low component maturity,and porosity.The average value is 7.94%,and the average permeability is 0.63×10-3μm2;②The pore types are mainly:residual intergranular pores,feldspar solution pores,mold pores,etc.,followed by the combination type:residual intergranular pores-long rock and cuttings dissolution pore-microporous type,micro-fine throat,with a small amount of middle throat,low-porosity,special-ultra-low permeability reservoir;③Compaction,cementation,dissolution,metasomatism,etc.diagenesis.The effect is the key factor leading to the difference in the pore structure of the Chang 8 reservoir in the study area.Compaction and cementation are the main reasons for the destruction of the pore structure of the reservoir and the densification of the reservoir.The average reduction rate of pores by compaction is 16.61%.The average porosity loss of cementation is 18.28%,and dissolution has a reforming effect on the reservoir,but the effect is limited.
作者
王晓琳
张小莉
王祥
杨振
李亚军
WANG Xiaolin;ZHANG Xiaoli;WANG Xiang;YANG Zhen;LI Yajun(Department of Geology/State Key Laboratory of Continental Dynamics, Northwest University, Xi′an 710069, China;National & Local Joint Engineering Research Center of Carbon Capture and Storage Technology, Xi′an 710069, China)
出处
《西北大学学报（自然科学版）》
CAS
CSCD
北大核心
2021年第5期877-890,共14页
Journal of Northwest University（Natural Science Edition）
基金
国家油气重大专项资助项目(2017ZX05005-002-004)。
关键词
储层评价
成岩作用
致密储层
长8
延长组
鄂尔多斯盆地
reservoir evaluation
diagenesis
tight reservoir
Chang 8
Yanchang Formation
Ordos Basin
