低渗气藏微观孔隙结构特征参数研究——以苏里格和迪那低渗气藏为例

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

低渗气藏具有低孔隙度、低渗透率等特点,其微观孔隙结构与中、高渗透气藏不同,而储层岩石的微观结构是影响低渗气藏储集及渗流特性的重要因素。利用恒速压汞技术研究了苏里格和迪那低渗气藏的微观孔隙结构及其分布规律。研究表明,不同渗透率的低渗气藏岩心其孔道半径基本相同,而喉道半径不同,平均喉道半径与渗透率有很好的相关关系。在此基础上,提出用平均喉道半径作为低渗气藏储层评价指标参数,来表征气体通过储层的难易程度。该研究成果可对低渗气藏的分类评价和合理高效开发提供科学的决策依据。

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.