A new model for improving the prediction of liquid loading in horizontal gas wells

There are great differences in predicting the onset of liquid loading among vertical, directional and horizontal gas wells. To date, most models for predicting the critical gas rate in horizontal wells are based on a liquid-droplet model, and the corresponding predictions deviate significantly from the actual status and are considerably controversial. Experimental results (Xiao et al., 2010; Wang, 2014) show that the liquid-film model is more reasonable. By respectively analyzing the force state of the gas core and the liquid film, we developed a new liquid-film model for predicting the critical gas rate in horizontal wells. Subsequently, a correction term is introduced for a convenient comparison between the new model and the popular models (Turner et al., 1969; Nosseir et al., 2000; Li et al., 2002). In addition, we carefully conducted a sensitivity analysis of the correction term related to the three parameters: liquid viscosity, Bond number and lift force factor. Well data from Liao (2012) were employed to verify the new model. The prediction results show that the new model demonstrates a significant improvement over conventional models in matching the field data in the Sebei gas reservoirs in China.