Cocompetitive Characteristics and Quantitative Design of Engineering Parameters for Coal Gas Predrainage Boreholes

Quantitative design of the optimal gas extraction engineering parameters has always been a key scientific problem to meet predrainage target coal seam, which is paid great attention and urgently expected solve for mine. In this paper, governing equation evolution seam content established under interference cooperation by boreholes, calculation formula cooperative efficiency defined. Based on gas-air mixed flow, multifield coupling 3d model using boreholes was developed. The content, method, principle spacing parameter borehole were proposed, constraint conditions objective function constructed. flow characteristics in area influence different effect are studied. competitive behaviors revealed. results show that spacing, fracture permeability, adsorption constant have significant effects synergistic extraction, while negative pressure matrix permeability little effects, but concentration. Finally, Comsol With Matlab used multiconstraint nonlinear optimization drainage along 18401 working face Tunlan Coal Mine. actual investigation very remarkable, provides quantitative basis