Linear and non-linear analysis of flow instability in gas-lift wells

► We perform linear and non-linear analyses of flow instability in gas-lift wells. ► The largest reduction in oil production occurs in case of the most severe heading in the well. ► The frequency of flow rate and pressure oscillations increases with increase in gas injection rate. ► An increase in the depth of the injection point may result in heading. ► Casing heading and density-wave oscillations occur simultaneously at high separator pressure