A new model for predicting liquid loading in deviated gas wells

Abstract

Liquid loading, which can reduce the gas rate and even kill the gas well, is one of the most serious issues in maturing gas wells. Accurate prediction of the inception of liquid loading will help operators choose the countermeasure in time to prevent such conditions happening. However, the modeling of liquid loading behavior still remains controversial and the predicted critical gas rate is not very reliable, especially for deviated gas wells.This paper presents a new model to predict liquid loading in deviated gas wells. The new model divides the fluid in the wellbore into the gas core in the center of tube and the liquid film near the tubing wall, and constructs the force balance of the liquid film and the whole fluid to calculate the critical liquid-carrying gas velocity. Then a correction term equation is developed to compare the new model with the Turner model (Turner et al., 1969) that is the most popular model in predicting liquid loading in gas wells. Subsequently the sensitivity of the correction term for different well parameters including inclination degree and tubing diameter are discussed. Based on the current work, a correction term reference table is given for field application.Well data from Gao (2012) and Belfroid et al. (2008) were employed in this paper to validate the new model. The prediction results from the new model show a great improvement over the Turner model and are even better than Belfroid model in matching the Belfroid data.The new model is accurate and can be used easily to predict liquid loading in deviated gas wells.