Reservoir characteristics of tight sandstone gas reservoir in He 1 member of Iiuyangpu gasfield

The reserving and seepage capability of tight sandstone gas reservoir in He 1 member of lower Shihezi formation,Liuyangpu gasfield of Ordos basin were poor,which restricted the distribution of gas reservoir capacity and therefore,the study on reservoir characteristics was greatly needed.The results indicated the reservoirs in He1 member was mainly of lithic quartz sandstone,followed by quartz sandstone,lithic sandstone and feldspar quartz sand.The average porosity and permeability were 5.8%and 0.42 × 10~(-3)μm~2 respectively.The pores were mainly of intergranular dissolved pores,intragranular dissolved pores and micro cracks.The porosity and permeability were closely related to the pore-throat structure.According to the shape of capillary pressure curve and the characteristics parameters,such as the median pressure,the expulsion pressure and the average radius of pore-throat,the capillary pressure curve was divided into three types.Through comprehensive study of reservoir lithology,physical properties,microscopic pore-throat characteristics,logging parameters,production testing characteristics and their relationship,the reservoirs of tight sandstone gas reservoir in He 1 member were divided into three types,the better ones,the ordinary ones and the ineffective ones,among which the first two types were the target in the late gas reservoir development.