Reservoir-Wellbore Coupled Simulation of Liquid Loaded Gas Well Performance

Abstract

Liquid loading of gas wells causes production difficulty and reduces ultimate recovery from these wells. In 1969, Turner proposed that existence of annular two-phase flow at the wellhead is necessary for the well to avoid liquid loading. In this work we applied Turner’s approach to the entire wellbore. Analysis of available data from literature showed that transition from annular flow occurs much earlier at well bottom than at the wellhead. This entire wellbore approach proved to be more accurate in predicting onset of liquid loading. In addition, we developed a simple pseudo-steady-state reservoir flow model that was seamlessly connected to a wellbore two-phase flow model. The model is capable of predicting the time a gas well will produce without getting loaded with liquid and the length of time it can produce since loading inception if no intervention is carried out. We were able to develop a normalized time function applicable many reservoirs that would be indicative of loading-free productive life of a gas well.