Characteristic Parameters of Microscopic Pore Structures of Low Permeability Gas Reservoirs ——By Using Sulige and Dina Low Permeability Gas Reservoirs for Example

Low permeability reservoirs had the characteristics of low porosity and low permeability,its microscopic pore structure was different with that of middle and high permeability gas reservoirs,while the micro-structure of reservoir rock was the major factors influencing its low permeability gas reservoirs and percolation characteristics.The microscopic pore structures and the distribution rules of Sulige and Dina low permeability gas reservoirs were studied by means of constant rate mercury penetration technique.The result shows that cores from low permeability gas reservoir with different permeabilities have the same pore throat radius with different radius of throat path,the average throat radius has good correlation with permeability.On the basis of the study,it is proposed that the average throat radius is used as an index for evaluating the low permeability gas reservoirs for characterizing the level of gas going through reservoirs.Basis is provided for a scientific decision on identification,evaluation and rational and effective development of the low permeability gas reservoirs.