Analysis of fractured well productivity in low-permeability stress-sensitive gas reservoir

The seepage problem in gas well with vertical fractures is converted to one-dimensional ribbon seepage which is easy to be solved by using conformal transformation principle.Based on Forchheimer binomial flow equation,a productivity formula of wells with vertical fractures in low-permeability stress-sensitive gas reservoirs has been deduced by taking account of threshold pressure gradient and stress sensitivity of permeability,and a production formula under conditions of low pressure and high pressure has been derived through simplification.The formulas have been verified with field data,and theoretical production curve has been constructed and analyzed.The results show that threshold pressure gradient and stress sensitivity can influence the productivity of fractured wells;the production of fractured gas wells decreases with the increase of threshold pressure gradient or stress sensitivity;when gas well is high yielding,non-Darcy flow effect must be considered.