Engineers rely on steady inflow and consistent jet pump performance to maintain drawdown and production targets. Gas interference disrupts both. While jet pumps tolerate gas better than many lift systems, too much free gas at the intake reduces energy transfer in the throat and diffuser. This article explains how to recognize gas interference, investigate root causes, and correct the issue using operational adjustments and design checks.
What Gas Interference Looks Like
Gas interference appears as:
- Irregular intake pressure
- Cyclic flow or intermittent liquid movement
- Lower drawdown than power fluid modeling predicts
- More sensitivity to rate changes than expected
These symptoms point to reduced momentum transfer in the mixing section. When gas volume increases, the jet loses efficiency and cannot pull reservoir fluids into the throat as designed.
Why Gas Interference Occurs
Common sources include:
- Gas breakout due to declining bottom-hole pressure
- Higher GOR from natural reservoir changes
- Inadequate surface separation before recirculating power fluid
- Flow regime changes in deviated or horizontal wells
Each source affects fluid density and impacts the jet pump’s ability to generate predictable suction pressure.
Diagnostic Steps
- Check flowing pressure trends
Intake pressure below the required minimum will make the jet unstable. - Evaluate the power fluid rate
A lower-than-planned power fluid stream reduces jet velocity and increases sensitivity to gas. - Confirm power fluid quality
Gas carry-under from surface tanks or separators can re-enter the system if surface handling is insufficient. - Review well data
Look for recent GOR increases, choke changes, or offset-well activity that may influence inflow.
Corrective Actions
- Increase power fluid rate to create a stronger jet and stabilize mixing.
- Adjust nozzle and throat sizing to handle higher gas volumes more effectively.
- Improve surface separation to limit gas entering the power fluid circuit.
- Modify choke or surface controls to stabilize inflow changes that trigger gas surges.
Gas interference rarely resolves on its own. Consistent monitoring and small operational changes can restore steady production and protect system efficiency.