Analysis and experimental study of negative effect of water on gas migration

The influence of water on the gas migration in coal seam is the factor that must be taken into account in the study of hydraulic fracturing. In order to improve the effectiveness of hydraulic fracturing technology in the application of coal seam permeability, this paper analyzes the negative effect of water on gas migration. The WYS-800 servo automatic loading system is used to design the experiment. The permeability of Yu-wu coal samples with different water content under the condition of three axial stress was studied. It is proved that under different confining pressures or different effective stresses, the permeability and seepage velocity are nonlinear decreasing trend with the water content. The conclusion is combined with conclusion that the hydraulic fracturing makes the fracture structure change and the permeability increases. At the same time, taking Yu-wu as an example, The optimum radius of hydraulic fracturing is found in engineering application, which provides theoretical and technical support for the layout of hydraulic fracturing wells.