Abstract
A dimensionless inflow performance relationship (IPR) curve that is a function of permeability has been developed for unfractured gas wells. Both numerical and analytical methods were used to solve the non-Darcy, gas flow equations. This analysis showed that the current dimensionless IPR curve for unfractured gas wells in pseudosteady-state flow is basically independent of all relevant variables, except permeability. The proposed current dimensionless IPR curve has the same general form as the familiar Vogel dimensionless IPR curve for solution-gas-drive oil reservoirs, with the coefficients of the proposed dimensionless IPR curve being a function of permeability. The proposed current dimensionless IPR curve can be used to predict the deliverability of a gas well using a single-point test, as opposed to a standard four-point deliverability test, if the permeability of the well is known. A future dimensionless IPR curve to predict future gas well deliverability that is a function of permeability is also presented. The time to reach pseudo-steady state flow for an unfractured gas well is two to three multiples of the time predicted by the commonly used, stabilization time equation.
