Paper: Using Chokes In Unloading Gas-Lift Valves

This paper presents the practice of using downstream chokes in unloading injection pressure operated (IPO) gas-lift valves. The practice helps to assure effective unloading and may provide protection against erosion damage during the unloading process. It has several other benefits that are discussed in the paper. A gas-lift valve/choke model has been developed. It provides accurate predictions of the gas passage through the choked valve during the unloading process. And, it can help to analyze existing gas-lift performance, where the objective is to determine which valve(s) are open and how much gas is being injected through them. This model is described in the paper.