Mature gas wells tend to suffer from flow rate fluctuations due to an inability to remove liquids. Flow-rate stabilization is essential for profitable operation of these wells. Moreover, the use of nozzles can help make in-situ foam treatments more efficient. The combined use of venturi nozzles and foamers is proposed as a novel artificial lift method. The effect of downhole venturi nozzles on flow stabilization of gas wells has been experimentally investigated. Air-water flow was studied in a 2” vertical pipe. The effect of the nozzles on in-situ foam generation was also studied.

Using the principles of Nodal Analysis, it was observed that the use of downhole venturi nozzles significantly improved the stability of production. The nozzles induce back-pressure on the flow inlet. The smaller the throat diameter is, the greater the back-pressure is. Therefore, proper sizing of the nozzle is important. Flow through the nozzles was characterized using CFD simulations and a sizing methodology has been proposed.

Foam flow was studied for injection before and after the nozzle at very low concentrations of a commercial foamer. The presence of the nozzle during foam flow did not affect the pressure gradient or holdup characteristics significantly when compared to foam flow without nozzle. However, the foam stability and quality were affected by the nozzle, depending upon the position where the foamer was injected (either before or after the nozzle).