Development of a controlling and decision-making system for coalbed methane drainage vertical wells

Rational working system is the key to enhance gas production and save cost of the coalbed methane wells.According to extension characteristic of the fractured crack in coalbed methane wells,changing characteristic of the phase state during drainage,combined with pressure transferring model,and the Langmuir adsorption model,distinguishing identifiers in the different drainage stages were gained.Based on KGD model,combined with fracturing operating parameter and the relation between permeability and porosity,the permeability prediction models in the direction of minimal and maximal horizontal stress were built.Based on Darcy laws,combined with positive and negative effect of coal reservoir,the changing models of parameters in different drainage stages were built.Based on the pressure transferring characteristic and change of gas and water relative permeability,the drainage intensity models in the different drainage stages in the different processes were built;with the developing tool of VB,a controlling and decision-making system for coalbed methane drainage from vertical wells was developed.Results showed the preferable application prospect.