Effect of well trajectory on liquid removal in horizontal gas wells

Experimental results indicate that under stable conditions, toe-up is the best configuration for the displacement of the produced fluids from the toe to the kick-off point. However, at very low gas flow rates, severe slugging is observed in this configuration. Furthermore, for the toe-down, one-undulation with a sump, and one- undulation with a hump configurations liquid loading is observed in both lateral and vertical sections of the well. Consequently, significant liquid accumulation and an eventual slugging condition are observed in the well. It was observed that the measured critical gas velocity to avoid liquid loading is lower than gas velocity at the minimum pressure gradient, indicating that minimum pressure gradient criterion is not enough to determine whether the well will be under stable or unstable conditions. Finally, toe-down configuration presents the largest liquid accumulation in the lateral section, indicating lower efficiency to remove liquids from the toe to the kick-off point.