Valve nozzle shape effect on gas lift system performance

Experiments were carried out using conical, bevelled entrance, bullet and orifice gas lift valve nozzle shapes with port diameter of 5 to 12 mm to study the effect of gas lift valve nozzle shape on the continuous flow gas lift system efficiency. A nitrogen-glycerin with nitrogen injection rate of 0.033 to 0.167 L/s flow through 50 mm diameter transparent vertical pipe and 3 m height to simulate a continuous flow gas lift system. Taylor bubble length and liquid produced mass were measured. The flow pattern was observed and the image was recorded using digital single-lens reflex camera. It was found that only slug flow occurred and gradual conical nozzle shape enlargement reduced the energy loss within the valve. The overall results show that conical nozzle produced the highest efficiency due to the less energy losses within the valve nozzle and most stable gas flow achieved in the fluid column pipe.