鄂尔多斯盆地南泥湾油田三叠系长6组储层物性影响因素研究

Influential Factors of Reservoir Performance of Triassic Chang 6 Formation Reservior in Nanniwan Oilfield,Ordos Basin

鄂尔多斯盆地南泥湾的主力油层是三叠系延长组长6油层组,通过研究区内大量岩心观察、铸体薄片及物性等资料分析,并对储层岩石学特征、孔渗特征及孔隙类型等进行了深入研究,并分析了影响储层储集性能的主要因素。研究区以内陆淡水湖泊河控三角洲沉积为主,储层岩石类型主要有长石砂岩、岩屑主要为变质岩岩屑,成分成熟度普遍较低,结构成熟度好;成岩作用主要为压实作用、胶结作用和溶解作用,孔隙类型以粒间孔、次生溶孔为主。优质的储层多分布于三角洲前缘水下分流河道和河口坝。沉积作用、成岩作用均对储层物性有重要影响。

Chang 6 oil reservoirs of triassic Yanchang formation are main producing oil layers in Nanniwan area,Ordos basin.Through the core observation,analysis of cast thin section and physical property of the reservoir,characteristics of lithology,physical property and pore types of the reservoir were studied,main factors of influencing physical property were also analyzed.The results show that microfacies characteristics of sedimentary facies in study area are inland freshwater lakes and river-dominated delta deposits,main rock type is feldspathic sandstone,debris type is metamorphic lithic debris,compositional maturity is generally low,but structure maturity is high;diagenesis is mainly compaction,cementation and dissolution;pore types are mainly intergranular pores and secondary solution pores.Distribution of favorable reservoirs is mostly in the sand bodies in delta-front underwater distributary river channel and river mouth bars.Tectonics,sedimentation and diagenesis all have effect on reservoir performance.