Abstract

One of the most important parameters for analyzing wellbore pressure response in gas condensate reservoirs is the pseudopressure function. This function correlates the reservoir pressure and saturation distributions, and hence the non-linear governing equation can be transformed into a linear equation and solved using a standard method.

This paper describes a method of analysing wellbore pressure response of a gas condensate reservoir under transient conditions. In this study, the pressure distributions are calculated using iterative line source approximation and superposition principles. Initially, the steady-state saturation is assumed. The reservoir saturation distributions are estimated from the sandface saturation and the two-phase flow radius using a quadratic equation. The pseudopressure function is then calculated based on these distributions. The pressure distribution is then recalculated based on this saturation distribution. The material balance method is used to verify the saturation distributions. The dimensionless wellbore pseudopressure is calculated from the wellbore pressure data and compared with the dimensionless pressure (liquid solution).

In general the proposed method shows a good agreement with the liquid solution during transient conditions and hence it can be used to estimate the transport properties of gas condensate reservoirs.