An improved model for the liquid-loading process in gas wells

This paper introduces an improved model for describing the liquid-loading process in gas wells. The model is an extension of the model proposed by Dousi et al. (2006). The Dousi model handles the downhole inflow and outflow between the well and the reservoir in a simple manner. The new model improves this aspect and makes more-realistic and -detailed assumptions with respect to the production and injection interval. Analysis of the results this new model produces improves the understanding of the processes occurring down-ole. This analysis can also be used to predict future behavior of the well in a more realistic fashion. As in the Dousi model, two typical flow rates could be found, with one at full production with all the fluids produced to the surface and the other one a metastable rate in which produced fluids are being reinjected into the reservoir. Field observations confirm the existence of two possible flow rates in many wells. The difference between the new model and the Dousi model is that changes in flow rates occur more slowly when liquid loading starts, reflecting the more-realistic inflow-performance assumptions. With this model, liquid-loading processes in the well can be understood better and predicted. This is important for optimization of well performance and for the economic assessment of the well and field. Copyright © 2008 Society of Petroleum Engineers.