Gas productivity based on reservoir uncertainty analysis in Gujiao Block

The development of the Gujiao Block faces the problems of low average gas production and large difference in gas production effect between wells. The key to the later development of the block is to clarify the main controlling factors of productivity and propose targeted measures to increase production.Based on the reservoir physical properties and production characteristics of Gujiao block, a typical numerical simulation model of Gujiao block was established. Based on the physical properties and production characteristics of the Gujiao Block, a typical numerical simulation model for the Gujiao Block was established. Based on the typical model, combined with the distribution range of reservoir parameters, a numerical simulation model with different parameter combinations was established by Monte Carlo interpolation method. Through parameter sensitivity analysis, the main factors affecting productivity and inter-well interference were obtained. The research results show that gas content and cleat permeability are the main factors affecting gas production. The formulation of the drainage system should focus on the gas-bearing nature of the reservoir and the cleat permeability. When water production is first determined and then bottom-hole pressure is fixed, the cleat permeability increases, the cumulative gas production increases first and thenLMdecreases; when the bottom-hole pressure is determined, the cleat permeability and the cumulative gas production have a positive linear relationship. Under the same gas content condition, the final cumulative gas production of constant bottom hole pressure production is higher than the final cumulative gas production after first setting the water production rate and then constant bottom hole flow pressure production. Cleat permeability and fracture permeability are the main factors affecting pressure drop expansion and gas production effect. When the cleat permeability is 9.7×10-10 m2 and the fracture permeability is 9.7×10-9 m2, the pressure drop is mainly affected by the cleat permeability; when the cleat permeability is 6×10-11 m2 and the fracture permeability is 3×10-9 m2, the pressure drop is mainly affected by the fracture permeability. Therefore, it is necessary to strengthen the permeability and gas content monitoring in the later development process and formulate a reasonable production system according to the reservoir conditions. Meanwhile, the Gujiao Block has an average permeability of 1×10-10 m2 and a well spacing of 300 m. It is difficult to achieve inter-well interference.In the later stage, volume fracturing stimulation can be considered to increase the overall permeability of the reservoir or to drill infill wells to achieve stable production and increase production. The research results provide development suggestions for stable and increased production of CBM wells.