Dimensionless Inflow-Performance-Relationship Curve for Unfractured Horizontal Gas Wells

Abstract

Abstract A dimensionless inflow performance relationship (IPR) curve that is a function of horizontal permeability, average reservoir pressure, reservoir height, and reservoir drainage area has been developed for unfractured, horizontal gas wells. The Babu and Odeh horizontal oil well flow equations were modified to account for non-Darcy flow effects and mechanical skin effects and also transformed into pseudopressure form. The pseudopressure equations were solved using analytical methods and Monte Carlo simulation to yield dimensionless IPR curves. This effort showed that the proposed dimensionless IPR curve for unfractured, horizontal gas wells in pseudosteady-state flow is basically independent of all variables except horizontal permeability, average reservoir pressure, reservoir height, and reservoir drainage area. The proposed dimensionless IPR curve is similar in form to the familiar Vogel equation, but only has one coefficient, which is a function of horizontal permeability, average reservoir pressure, reservoir height, and reservoir drainage area. The proposed dimensionless IPR curve can be used to predict the deliverability of a horizontal gas well using a single-point test, as opposed to a standard four-point deliverability test, if the height of the reservoir is known.