Abstract:With the development of the petroleum exploration, deep oil and gas reservoirs become more and more important. The Yongjin area is one of the three blocks in the interior of the Junggar basin explored by the Sinopec. The exploration target in the Yongjin area is deeper than 5 500 meters, with reservoirs mainly consisting of fine sandstone and pebbled sandstone, skeleton grains being characterized by higher ratio detritus, lower compositional maturity, lower texture maturity, with very low porosity and super low permeability. There are five kinds of pores i.e. relict intergranular pore, intergranular emposieu, intragranular emposieu, argillaceous micropore and microfissure, with pore textures of very low porosity and microfine throat. The main influencing factors with respect to reservoir physical properties are intense squeezing action, dissolution, the coversion of clay minerals, which tend to decrease the porosity and permeability of the reservoir. There are stratigraphic and lithological oil and gas reservoirs in Yongjin area, the reservoir formation model is expressed by oil and gas from basal hydrocarbon source rock migrating along faults and layers and then being accumulated in the upper reservoir.