Advantages and limitations of venturi gas lift valves

摘要

The venturi-nozzle, or simply venturi, gas lift valve is increasingly being used in continuous gas lift wells worldwide.1"4 In Brazil, about 250 offshore wells are now equipped with these valves. Two types of gas lift valves are typically used in the oil and gas industry. The first type uses a mechanism, usually a charged bellows, to open or close the valve according to wellbore pressure and/ or temperature. The second type involves valves that are always open (in the casing-to-tubing direction). They are composed of a choke to restrict the flowrate and a check valve to avoid reverse flow from tubing to casing. The most widely used choke is a cylindrical plate with a squareedged orifice. Alternatively, a choke with a venturi geometry may be used.