富县北部地区侏罗系延9砂岩储层特征

Characteristics of Yan 9 sandstone reservoir in northern Fuxian aera

为进一步研究富县北部地区延9砂岩储层特征,文中利用大量岩矿分析、物性分析、铸体薄片、扫描电镜和压汞资料,对延9储层砂岩的岩石学特征、孔隙结构和孔隙类型进行研究,并进一步分析了储层控制因素。结果表明:储层岩石类型主要是细粒长石岩屑质石英砂岩,成分成熟度较高,结构成熟度中等;岩石物性总体较好,属于中孔中低渗储层,发育剩余原生粒间孔、粒间溶孔、粒内溶孔和铸模孔等孔隙类型,喉道以中喉为主。研究区储层物性受控于沉积因素和成岩作用,压实作用和胶结作用使储层物性变差,溶蚀作用是储层物性改善的主要因素;不同沉积微相的储层物性差异较大,水下分流河道的储层物性最好,同时也是油气聚集的有利相带。

In order to study the characteristics of Yan 9 sandstone reservoir in northern Fuxian aera of Ordos Basin,petrological characteristic, pore structure features and pore types of Yan 9 sands are analyzed based on rock mineral analysis, physical property analysis, cast thin section, scanning electron microscope and mercury penetration data. And main controlling factors for reservoirs were analyzed. The results show that the lithology characteristics in this area are mainly detritus feldspar sandstone and feldspar sandstone ,which have the characteristics of high compositional maturity, middle texture maturity, medium-porosity and medium-low permeability reservoir. The reservoir develops the primary residual in- tergranular pores,interparticle dissolution pore, intragranular dissolved pores and casting pore. The main throat types is the medium throat. The physical properties were doubly affected by diagenesis and sedi- mentary microfacies. The compaction and cementation made physical properties obviously low,while dis- solution is the main factor for improving the physical property porosity of the reservoir. Porosity and permeability of different sedimentary microfacies is extremely different, subaqueous distributary channel microfacies were favorably facies belt for hydrocarbon accumulation, which is the best.