Analysis on gas drainage area affected to gas production potential of single coalbed methane well

Zhang Fenna; Qi Yaoguang; Li Mingzhong; Chen Bo; Meng Shangzhi

doi:10.13199/j.cnki.cst.2017.03.017

Abstract：According to a short effective drainage time of coalbed methane well,based on the stable seepage equation of coalbed methane well and the Langmuir adsorption law,a mathematical model of drainage area of radial flow coalbed methane well and the fractured coalbed methane well affected to gas production potential of single well was established.The drainage area affected to gas production potential of single well was analyzed and the effective desorption boundary controlled by the single coalbed methane well was studied.The results showed that the variation tendency between desorption volume and desorption radius of fractured coalbed methane well and radial flow coalbed methane well was almost the same.The desorption volume would be close to a quadratic function variation with desorption radius increased.The desorption radius was increased by 10 times and desorption volume was increased by about 46 times.The larger of the drainage area was,the higher gas production potential of coalbed methane well would be.When the bottom pressure of radial flow coalbed methane well was 1.0 MPa,the desorption boundary radius controlled by the single well would be 99.73 m.The study on the effective desorption boundary would provide the basis to the rational layout well network of the coalbed methane mining.