Characteristics of Yan 9 sandstone reservoir in northern Fuxian aera

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 intergranular 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 sedimentary microfacies. The compaction and cementation made physical properties obviously low,while dissolution 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.