Experimental Study On The Seepage Characteristics On The Plane Direction In The Tight Sandstone Reservoir

With the rapid development of the world oil and gas industry,those large-scale,high-quality oil and gas resources become less and less.Some oil and gas resources which is low grade and need higher technical requirements gradually become a hot spot in oil and gas exploration and development.although the development efficiency is relatively poor.The proportion of oil and gas resources output in tight sandstone has gradually increased in the total oil and gas production,which plays an important role in the stabilization and production of oil and gas.A large number of exploration and development practices and research results show that the complex seepage characteristics of tight sandstone reservoirs are the main factors affecting production capacity and development,and the microstructure of reservoir and the presence of fractures is the key to the reservoir permeability anisotropy.In this paper,based on the analysis of the geological characteristics of the tight sandstone reservoir and the influence of the fracture on the seepage flow,study the causes of the permeability anisotropy of the tight sandstone reservoir.Anisotropy is generally formed as result of orientation of asymmetric grains making up the solid matrix of porous media and naturally fracture in porous media.Then,based on the two major causes of reservoir anisotropy,two main research contents are carried out to study the seepage characteristics of tight sandstone reservoirs.The physical experiments of horizontal single-slit rock and the physical experiments of parallel double-slit rock are carried out to study the seepage law of stable fluid,the relationship between fracture permeability and effective stress,and the relationship between crack width and fracture permeability in horizontal cracks.The specific arrangement of the particles during the deposition process results in a good fluid channel along the direction of the flow,while the conductivity and permeability in this direction are correspondingly larger.Based on this principle,a method of obtaining the main direction of the permeability of the tight sandstone by using the circumferential conductivity test and the three-point permeability verification test is proposed.The feasibility of the method is verified by the test examples.