Hydraulic pumping units are an essential component for producing oil and gas from wells. These mechanical devices utilize hydraulic power to turn an eccentrically rotating crank, which operates the sucker rods in the wellbore to extract subsurface fluids. Hydraulic pumping units provide efficient, reliable artificial lift that enables continued production when reservoir pressure is no longer sufficient.
In blog post, we’ll provide an in-depth overview of hydraulic pumping unit systems, their components, operational principles, and applications in oil and gas production.
What Is A Hydraulic Pumping Unit?
A hydraulic pumping unit (HPU) consists of a power end and a pumping end. The power end contains a hydraulic motor powered by an engine or electric motor. This hydraulically drives the pumping end which transforms the rotary motion into vertical reciprocating motion to lift fluids to the surface.
The key components of a hydraulic pumping unit include:
- Hydraulic Motor – Powers the system using pressurized hydraulic fluid.
- Hydraulic Reservoir and Control Valve – Stores fluid and regulates flow to the hydraulic motor.
- Gear Reducer – Reduces speed from the motor while increasing torque.
- Pitman Arm – Connecting rod that converts rotating motion to reciprocating motion.
- Crank/Counterweights – Provide counterbalance and change the stroke angle of the pitman arm.
- Sucker Rod String – Transfers mechanical energy down the wellbore to lift fluids.
- Prime Mover – Provides rotational power via an electric motor or IC engine.
How Do Hydraulic Pumping Units Work?
The prime mover spins the drive shaft which turns the hydraulic pump to pressurize fluid from the reservoir. The pressurized fluid flows through control valves into the hydraulic motor, causing it to turn the gearbox and crank.
The crank is attached to the pitman arm which moves up and down, converting the rotation into linear oscillating motion. This pushes and pulls on the sucker rod string, essentially a long vertical piston that lifts oil up the production tubing to the surface.
The counterweights provide a counterbalancing force against the weight of the rod string allowing the motor to raise and lower the rods more efficiently. The stroke length can be adjusted to optimize fluid production based on well conditions.
Key Benefits of Hydraulic Pumping Units:
- Efficient Artificial Lift – Lift fluids when reservoir pressure is inadequate.
- Adjustable Stroke Length – Optimize production by changing stroke length.
- Constant Torque Output – Hydraulics provide steady torque compared to rod pumps.
- Lower Operating Costs – Require less maintenance and downtime than beam pumps.
- Reliable in Harsh Environments – Motor enclosed in protective structure.
- Automation Capabilities – Can integrate sensors and process control equipment.
Applications of Hydraulic Pumping Units:
- Secondary Recovery – Lift reservoir fluids after primary pressure depletion.
- Deep Wells – Can economically lift fluids from depths of 10,000 ft or more.
- Remote Operations – Built to withstand harsh conditions and operate unmanned.
- Offshore Platforms – Compact footprint ideal for space-constrained platforms.
- Directional and Horizontal Wells – Effective for lifting fluids from deviated wellbores.