Liquid loading occurs in most of marginal natural gas wells. Many models have been developed to predict the inception of liquid loading. Detailed review of these models and comparison between droplet model and film models are presented in the paper. The results show that film model is more accurate for predicting liquid loading than droplet model. This indicates that film reversal may be the main reason of liquid accumulation in the wellbore. A new model is developed, which includes non-uniform film thickness around pipe. The model is able to improve the prediction of liquid loading, especially for inclined wells.
Different models are examined using both field and lab data. Film model shows much better agreement with the data than droplet model. The effect of inclination angle is validated using Veeken's field data. The new film model shows a significant improvement compared to droplet model as well as other film models.