Analysis of Influence Mechanism of Interference Mode Between Drainage Wells on CBM Extraction Based on LBM Method

It is of great significance to find out the mutual interference mechanism between CBM drainage wells to rationally arrange well networks and improve CBM recovery. To this end, Lattice Boltzmann Method （LBM） was used to reproduce the migration process of CBM from cleat space to drainage wellhead, and the influence mechanism of different drainage parameters and mutual interference between CBM drainage wells on gas production were systematically analyzed. The results showed that the difference of gas production between wellbores showed fluctuation characteristics with the change of well spacing due to inter-well interference. If single well gas production was considered, inter-well interference had segmented effect on gas production. When the spacing of Ds between wells was less than 382.5 lu, it showed inhibiting effect; otherwise, it showed facilitation. Too small well spacing was not conducive to CBM production. When the well spacing exceeded the critical threshold of 382.5 lu, the recovery rate of CBM could be accelerated. The power law relationship ■≈3.2△p0.94 was followed by mean velocity ■ of CBM in wellhead and pressure difference △p.