Modeling of liquid unloading using coiled tubing in horizontal gas wells

Abstract

This article studies the flow simulation for liquid unloading using coiled tubing in horizontal gas wells. A semianalytical reservoir model, coupled with a wellbore model under nonisothermal, steady state conditions is used to calculate the distribution of gas velocity along the wellbore. The coupled model takes into account the effect of the wellbore trajectory type on the well performance. The minimum gas velocity for liquid removal is calculated using a model adapted for horizontal gas wells. An algorithm has been presented to estimate the well performance and the liquid unloading for different CT diameters, at various wellbore positions. The simulation results showed that the installation of 53.51 mm or 65.1 mm diameter coiled tubing at the toe ensure a good liquid unloading and optimum well performance.