Liquid loading is a common issue for gas producers. Better predictions of liquid loading will help operators in reducing costs (less shutdowns) and improve revenue (more production).
Turner's entrained droplet model is the most popular one in predicting liquid loading in gas wells. However, there were still quite a few wells couldn't be covered even after a 20% upward adjustment in the paper of Turner et al.. Field practice also proves that the adjusted model still underestimates liquid loading sometimes. By studying the droplet model and liquid film mechanisms, the paper presents a new empirical model.
Previous models for liquid loading are independent of the liquid amount in a gas stream. Once gas velocity is higher than calculated critical velocity, no liquid loading exists. This paper points out that, in addition to gas velocity, liquid amount (liquid holdup) in a gas stream is also a major factor for liquid loading. There is a threshold value for liquid amount in a gasliquid mixture. Above the value, liquid loading may appear even the gas velocity of a well is higher than the critical velocity form Turner's droplet model. The presented model is the first model including the amount of liquids in the calculation of gas critical velocity. According to the new model, critical gas velocity is not a single value, it varies with the liquid holdup in the gas well once the holdup excesses the threshold value.
Well data from Turner et al. were employed in the paper for evaluating the new model's parameters. Data from the paper of Coleman et al. were also used for the validation of the new model. The prediction results from the new model are better than those from Turner's model, and even better than Turner's adjusted model in matching Turner's data. The new model is consistent with Coleman's data and conclusion.
The new model is simple and can be evaluated at wellhead condition. It can be easily used to predict liquid loading in gas wells.