Study on the solution method of effective extraction radius based on gas radial seepage equation
ZHU Nannan
ZHANG Lang
FAN Xisheng
SHU Longyong
Abstract：In order to provide a simple and rapid method to solve the effective drainage radius,based on a gas radial unstable seepage equation proposed by Academician Zhou Shining,a self simulation method was applied to get the approximate solution,which would be the gas pressure distribution expression of the radial flow field.Thus a mathematical expression of the effective drainage radius was further established.The study showed that under the condition of an infinite flow field,the square root of the effective drainage radius and the drainage time would be in a direct ratio and the square root of the drainage negative pressure could meet the nonlinear positive correlation.Under the different drainage negative pressure condition,the gas pressure distribution law around the borehole would be small in difference.Therefore,a simplified gas pressure expression would be applied to approximately reflect the gas pressure distribution law of the radial flow field.The approximate solution and the effective drainage radius expression could be applied to determine the relevant parameters of the seam gas drainage.The related experiments were verified the accuracy of the effective drainage radius expression.
Keywords：radial flow fieldseepage equationgas pressureeffective gas drainage radius
Publication Date：2017-01-01