Study on reservoir development characteristics and main controlling factors of 5₁₊₂ member of Majiagou Formation in Gaoqiao Xinghe Area, Jingbian Gas Field

In order to ascertain the development characteristics and main controlling factors of Ma 5₁₊₂ member of the Majiagou formation in Gaoqiao-Xinghe Area of the Jingbian Gas Field, the pore structure and physical properties of the reservoir are analyzed by core thin section observation and mercury injection experiment, and the influence of diagenesis and tectonic factors in the sedimentary process on the reservoir space development is analyzed.The results show that the reservoir space of Ma 5₁₊₂ member is late gypsum solution pore, dissolution fracture and structural fracture.Its roar channel width is large, a small number of primary intergranular pores are developed, the pore roar is small, the overall reservoir permeability is low, and the permeability of fracture development section is significantly increased.The relationship between the surface degree and permeability of the Ma 5₁ sub-member is a simple linear relationship, while of the Ma 5₂ sub-member is not obvious.The gypsum deposit in the strong evaporation environment provided the material basis for the formation of the reservoir.The later period of dolomitization increases the brittleness of the reservoir, which would be conducive to the formation of structural micro-fractures.The dissolution of gypsum helps the formation of gypsum-dissolved pores.The filling of quartz and calcite destroys the formation of the reservoir space, and the micro-fractures produced by the tectonic process provide channels for the dissolution of gypsum.At the same time, it also enlarges the reservoir space and communicates isolated pores, which are the main factors for the development of later dissolved pores.