Comparison of Critical Gas Flow Rate Equations to Prevent Liquid Loading

Abstract

Liquid loading is a common problem in mature gas wells that may cease production if the problem is prolonged. Thus, it is required to check for the occurrence of the liquid loading problem. This paper aims to develop a work flow that predicts critical gas flow rate (minimum required gas flow rate) to prevent liquid loading based on the published literature and to analyze effects of temperature, pressure, conduit size, producing depth, and inclination on the critical gas flow rate. Turner et al. model and Guo et al. model are selected to develop a work flow. Fluid characterization is performed using the necessary inputs of fluid properties based on that stated in this paper. This work presents a work flow with two functions, which are estimating critical gas flow rate and performing sensitivity study. It is found that prediction of critical gas flow rate by the Turner et al. model is lower than that of the Guo et al. model. Analyses from sensitivity studies show that critical gas flow rate will be increased if temperature is reduced; pressure is increased; conduit size is increased; producing depth is increased or inclination is reduced. For the set of inputs utilized, the critical gas velocity and flow rate calculated by the Turner et al. model (10.139 ft/s and 0.701 MMscf/d) is lower than that of the Guo et al. model (11.689 ft/s and 0.827 MMscf/d). The success of this project will yield a better insight on liquid loading problem, and it is hoped that the developed work flow can be applied in the industry.