Quick Test

Plunger Lift

Plunger Lift
Plunger Lift

Plunger Lift Principle

A Plunger Lift system uses a free piston that travels up and down within the well's tubing string. This mechanism minimizes liquid fallback and utilizes the well's energy more efficiently than slug or bubble flow methods. By removing liquids from the wellbore, the system allows the well to produce at the lowest possible bottom-hole pressures. The mechanics are consistent across oil, gas, and gas lift wells:

  • Plunger Function: A steel plunger is dropped down the tubing to the well's bottom and travels back to the surface, acting as a piston between liquids and gas in the wellbore to prevent liquid fallback.
  • Energy Utilization: The plunger creates a seal that leverages the well’s own energy to lift liquids efficiently, reducing the need for high gas velocities.

Working Steps

  1. Shut-In Period:
    • The well is closed, allowing the plunger to drop to the well bottom.
    • Gas pressure builds in the casing, stored in the reservoir or near wellbore.
    • Sufficient pressure is accumulated to lift the plunger and liquid slug against line pressure and friction.
  2. Flow Period:
    • Unloading Phase: The plunger and liquid slug ascend to the surface.
    • Gas above the plunger flows into the flowline, aiding the plunger’s rise.
    • Upon reaching the surface, the plunger unloads the liquid, producing at high rates initially.
    • Post-Unloading: As flow rates decrease, liquid begins to accumulate, triggering the next shut-in period.
  3. Cycle Repeats:
    • The plunger returns to the well bottom to restart the cycle.
    • Optimal production is achieved by minimizing shut-in time and maintaining adequate gas pressure.

Advantages of Plunger Lift

  • No External Energy Source: Utilizes the well's inherent energy for lifting.
  • Cost-Effective: Low-cost artificial lift method with minimal maintenance.
  • Installation Ease: No rig required, simplifying deployment.
  • Maintains Well Cleanliness: Helps keep wells free from paraffin deposits.
  • Suitable for Gassy and Deviated Wells: Efficiently handles high gas content and crooked well paths.
  • Remote Operations: Ideal for remote locations without easy access to rigs.
  • Low Volume Applications: Effective for wells with production rates up to 200 BPD.

Limitations of Plunger Lift

  • Gas-Liquid Ratios (GLR): Requires specific GLRs to effectively drive the system.
  • Low Volume Potential: Limited to approximately 200 barrels per day.
  • Monitoring Needs: Requires regular surveillance to optimize performance.
  • Dependence on Well Conditions: Effectiveness varies with reservoir pressure and inflow performance.