STUDY ON WELL FLOWRATE PERFORMANCE OF LOW VELOCITY NON-DARCY PERCOLATION WITH FLOWING BOUNDARY

The fluid flowing boundary extends outwards continuously is the feature of pressure propagation with low velocity Non-Darcy percolation.Based on this situation,a fixed boundary mathematical model based on the pattern of low velocity Non-Darcy percolation with wellbore storage and skin effect is presented,and solutions of wellbore pressure in Laplace domain is worked out with Green′s function.The radius of flowing boundary of different time interval is then determined in accordance with the starting differential pressure needed by fluid from static to flowing condition,analytical solution of fixed boundary model is then used to calculate the correlation of wellbore pressure vs time,which is regarded as a numerical approximation of flowing boundary model.The wellbore pressure vs time curves have been developed by Stehfest method,and the influences of flowing boundary,starting pressure gradient,wellbore storage,skin effect and difference between Darcy percolation and Non-Darcy percolation were also discussed.