Principles of Operation and System Advantages
Artificial lift technologies are central to extending the productive life of oil and gas wells. Among these, hydraulic jet pumps offer a unique combination of simplicity, flexibility, and resilience in harsh well conditions. Unlike many lift systems that rely on reciprocating or rotating downhole mechanisms, the jet pump operates on fluid dynamics rather than moving parts, making it highly tolerant of sand, scale, gas, and paraffin. Jet pumps are powered by a pump at the surface, so any needed maintenance does not require a workover rig.
Principle of Operation
The jet pump artificial lift system functions by injecting pressurized power fluid from the surface into a specially designed nozzle and throat assembly downhole. This arrangement uses the Venturi effect: the high-velocity jet of power fluid entrains produced fluids, mixes with them, and carries them upward to the surface. The system depends entirely on surface-generated pressure differentials; no mechanical downhole drive is required.
Surface Components
At the surface, the heart of the system is the power fluid pump. Positive displacement pumps and multi-stage centrifugal pumps are most common. Surface pumps can be powered by electricity or a natural gas engine. Natural gas generators are used as well.
Key advantages of surface pumps:
Positive Displacement Pumps
- Conventional Plunger Pump – Mechanical Efficiency, common pump type for oilfield
- PD Diaphragm Pump – Low maintenance, mechanical efficiency, environmentally-friendly
Multi-stage Centrifugal – Low maintenance, environmentally-friendly
Other surface components include:
- Power-fluid filtration and conditioning systems.
- Return lines and circulation loops.
- Wellhead equipment allowing jet pump retrieval without slickline or workover rigs.
Downhole Components
The hydraulic jet pump itself is compact and simple, typically consisting of:
- Nozzle – accelerates the power fluid into a high-velocity jet.
- Throat – creates a low-pressure region that draws reservoir fluids into the mixing chamber.
- Diffuser – converts velocity into pressure, lifting the combined fluids to surface.
Because there are no moving parts, jet pumps avoid failure mechanisms such as bearing erosion, shaft seizure, or fatigue. The insert assembly can be circulated out and replaced without rig intervention, keeping intervention costs low.
Fluid Dynamics of Jet Pump Lift
The fundamental principle is based on momentum transfer between the injected power fluid and the formation fluids. As the power fluid enters the nozzle, it accelerates, creating a pressure drop as it exits. This differential pressure draws the reservoir fluids into the mixing chamber. The two streams combine, and the diffuser gradually converts velocity into pressure to lift the fluids up the tubing or casing (based on flow regime).
Optimization variables include nozzle size, throat diameter, and power fluid rate. Adjusting these parameters allows engineers to optimize the pump for high initial production rates or efficient operation during late-life, declining production.
Power Fluid Considerations
Choosing the right power fluid is essential:
- Produced water is most common and is filtered and re-circulated.
- Lease crude is typically used when oil cut is greater than water, or for other reasons like high corrosives or paraffin.
- Fresh water or treated brine may be chosen for effectiveness in corrosive or scaling environments.
Benefits of No Moving Parts Downhole
By eliminating downhole mechanical components, jet pumps deliver significant reliability benefits including:
- No bearings, shafts, or seals to fail.
- High tolerance for sand, scale, and gas slugs.
- Suitable for deviated or horizontal wells where mechanical strings are impractical.
- Quick retrieval and reconfiguration, which minimizes downtime.
The Advantage of using a surface pump to power a downhole pump
While using a surface pump to hydraulically power a downhole pump suggests less mechanical efficiency, the benefits can reduce overall LOE and deliver superior ROI compared to more conventional forms of artificial lift.
All rotating and reciprocating components of the system are located on the surface and do not require a “work over” to repair or replace, yielding reduced downtime and lost production, as well as reduced workover frequency.
This pairing of surface and downhole simplicity delivers a lift system with a low intervention frequency, strong adaptability across well conditions, and competitive lifecycle economics.
Conclusion
Hydraulic jet pump artificial lift is not the highest-efficiency method for every well, but it excels where conditions challenge mechanical systems: abrasive environments, deviated wellbores, and declining production. When driven by a pump at the surface, the system eliminates many of the chronic issues associated Reciprocating or rotating components located downhole. The combination results in a durable, low-maintenance artificial lift option well-suited to modern onshore and offshore production environments.