Applicability of Models for Liquid Loading Prediction in Gas Wells

Liquid loading phenomenon is known as the inability of the produced gas to carry all the co-produced liquid to the surface. Under such condition, the non-removed liquid accumulates at the wellbore resulting in reduction of the production and sometimes cause the death of the well. Several studies were carried out and correlation were developed based on field and experimental data with the aim to predict the onset of liquid loading in a gas well. However, each model provides different indication on the critical gas velocity at which the liquid loading exists. Thus, to have a clear understanding on the difference between most used models, experiments were performed in an upward inclinable pipe section. The 60-mm diameter test pipe was positioned at angles of 30°, 45° and 60° from horizontal. The fluids used were air and light oil. Measurements include fluid velocities and fluid reversal point. High-speed video cameras were used to record the flow conditions in which the onset of liquid loading initiated. Experimental results were compared with existing models by Turner et al. (1969), Barnea (1986), Belfroid et al. (2008), Luo et al. (2014), Shekhar et al. (2017) and with a commercial dynamic multiphase flow simulator from SPT-Group (OLGA2017.1.0®). Prediction using the liquid film models presented acceptable agreement with experimental.