Numerical Simulation Of Coalbed Methane Well

In this paper, the mechanisms of migration and production for coal seam gas are researched .A three-dimensional, two-phase mathematical model is also established, and three processes i.e. desorption, diffusion and percolation flow, undergone by coalbed methane from matrix surface into wellbore are considered. This model introduced the Langmuir isothermal absorption theory ,the first Pick theory to consider the absorption and diffusion of coalbed methane. After that, this complex mathematical model is approximated and solved by IMPES methods. In addition, the program source code was written. The data of coalbed methane wells of QuShi I was used to prove the reliability of this model. The Re-scaled range analysis (R/S analysis) is introduced and used for the production trend forecasting of coalbed methane and water . By using the theory of gray system ,the recursioncom penstaed gray-time model is established for the purpose of predicting the yield of coalbed methane. Examples show that the R/S method and GM(1,1) model could be a new way for the production forecasting of coalbed methane and water.