Plunger Lift Application in Wells With Set Packers or Permanent Tubing

Abstract

E&P Exchange Plunger lift is an artificial-lift method that uses energy from a well's own gas to lift accumulated fluids in the wellbore. The plunger acts as a mechanical interface between the gas and liquid in a well, with the gas forcing the plunger up the tubing, thus displacing the fluid above it. Plunger lift is successful primarily in high-gas/liquid-ratio oil and gas wells for constant liquid removal. Low bottomhole pressure from natural depletion normally causes fluid accumulation in the bottom of a well as the flowing velocity slows. Through intermittent pressure buildups and the use of bottomhole tools, the load can be delivered to the surface in a slug for a clean wellbore operation. This allows maximum production and more drawdown than natural flow, extending the life of the well. The various well conditions encountered when plunger lift is installed are somewhat similar, but each well's recovery, gas volume, and fluid load determine the proper equipment arrangement and the technique to be applied. Flexibility to adapt the plunger lift to the well conditions is a very important key to success. To determine whether a well is a good candidate for a plunger lift installation, a simple formula can be used. A minimum of 500 scf of gas per barrel of fluid per 1,000 ft depth is required for plunger lift to work. If this requirement is met, the well should have enough gas production and reservoir energy to lift the plunger and the fluids accumulated in the bottom of the well. Conventional use of plunger lift is in wells with an annulus that is open or in communication with the pay zone. The casing or annulus is used to store gas during the shut-in period. When the well is opened at the surface, the stored gas rises up the tubing, driving the plunger up the tubing, and delivering the well's fluid and gas to the surface. Until recently, the use of plunger lift in wells with set packers or permanent tubing was very uncommon.