In order to characterize the changes of fluid flow rule more effectively in the fractured gas reservoir and obtain a more predictable and applicable productivity equation which can forecast a more precise AOF( absolute open flow) c,a new solution of the productivity prediction equation for vertically fractured gas wells in low-permeability gas reservoir has been studied. Based on the steady flow theory and the percolation characteristics of gas well with vertical fracture,by introducing the Lame coefficient and the method of elliptic integral and considering the starting pressure gradient,the equation is proposed. The result indicates that as for the gas flow the starting pressure gradient is an additional resistance. The greater its value,the less the gas production is. Besides,the stronger the fracture conductivity and longer the fracture length,the less the overall pressure dropdown is,thus the greater the gas production is. Furthermore,in designing of fracturing process for the low-permeability gas reservoir, one of the key factors restricting gas production when the fracture conductivity reaches its peak,is elliptic flow ability. At this point,fracture length increasing is more important for purpose of enhancing recovery. The result of case study shows that the relative error of AOF is 2. 8%,compared with well testing method.
Science Technology and Engineering