The Research Of Characteristics And Its Controlling Factors Of Sandstone Reservoir Of Taiyuan � Shanxi Formation In Yonghe Area

Yonghe area,which is between Baode Liulin block and Daning Jixian block,located in the southwest of Jinxi fold belt,Ordos Basin belongs to the East.Ordos Basin in the upper Paleozoic era,the north and south direction of the supply of material.The Late Carboniferous and Early Permian,the shallow lake delta front sediments gradually transition to the delta plain,alluvial development.From the point of view of plane distribution characteristics.The north is mainly NW-SE to delta plain deposition and sand body formation in underwater distributary channel microfacies;southern development of delta plain distributary channel sand body and delta front underwater distributary channel sand body.By the drilling core data and logging data interpretation,combined with endoscopic core slice observation and experimental analysis,using statistical analysis methods,on the stone floor blocks west Yonghe area of Taiyuan Formation and Shanxi Formation sandstone sample storage layer characteristics and experimental analysis.The results of the study show that:(1)the types of sandstone is mainly lithic sandstone and lithic quartz sandstone and quartz sandstone;granularity is mainly in grain and coarse grain structure,fine,fine structure of Shan 1 section of common;separation medium,grinding roundness edges rounded shape,point line contact relation;fillings are mainly siliceous and argillaceous and carbonate cementation,content up to 15%.(2)The study area is low porosity,poor permeability,poor connectivity,low porosity,low porosity and low permeability.The reservoir space types include intergranular pores,intergranular pores,intergranular pore,moldic pore type etc..The reservoir physical properties in the study area are mainly influenced by the factors such as sedimentary facies,rock structure,diagenesis,etc.The sedimentary facies is the key factor,because the sedimentary environment and facies can influence rock structure,composition,maturity,diagenesis types.In the study area,the better sedimentary facies are underwater distributary channel and distributary bay.Diagenesis in reservoir physical property set has a dual role,not only canimprove the reservoir physical properties,such as leaching dissolution,dissolved impurity and other particles,changed for the better,but also can make the physical property becomes worse,such as compaction,cementation,blockage of the pores and throats,reduce the porosity and permeability.The diagenesis in Yonghe area includes compaction,cementation and dissolution.Among them,dissolution belongs to constructive diagenesis,compaction,siliceous cementation,infilling and metasomatism belongs to destructive diagenesis.According to the comprehensive analysis,the reservoir physical properties of the study area is poor,with low porosity,low permeability characteristics,belonging to class III reservoir.The favorable area is distributed in the sand body of the underwater channel,so the micro facies of the water flow in the Northwest can be used as the dominant block for further exploration.