In shallow-to-medium-depth extra-heavy oil wells, production can decline while the pump continues rotating. As oil cools, increasing flow resistance restricts entry into the pump and raises the load required to move fluid through the production string.

The challenge in artificial lift for heavy oil recovery is to maintain stable flow as these demands change. For oil rated at 20,000 mPa·s @ 50°C, this means coordinating pump filling, operating speed, torque, and clearance throughout the production cycle.

What 20,000 mPa·s @ 50°C Means for Lift Selection

At 20,000 mPa·s @ 50°C, viscous resistance becomes a substantial part of the lifting duty. Compared with less viscous oil under otherwise similar conditions, the fluid requires a greater pressure difference to pass through restricted flow paths and the production tubing, increasing the pressure and torque demanded from the lifting system.

At the pump intake, this resistance slows cavity filling. If rotational speed exceeds the rate at which oil can enter, actual production falls short of theoretical displacement, and additional speed delivers progressively less useful flow.

High viscosity also reduces internal leakage through rotor–stator clearances, which can support volumetric efficiency. Selection must retain that benefit while avoiding excessive resistance and mechanical loading from an overly tight working fit.

These effects become harder to balance as the well cools. The operating task is to identify whether intake restriction, lifting resistance, or changing pump clearance is controlling production, then adjust the system accordingly.

The Main Challenges in Artificial Lift for Heavy Oil Recovery

Identifying What Is Restricting Production

Declining output can result from restricted pump filling or increasing resistance above the pump. Both reduce useful production, but they call for different operating responses.

When filling is restricted, additional speed increases demand without a proportional increase in delivered fluid. When tubing resistance rises, maintaining the same flow requires more pressure and therefore greater drive torque.

Production trends should therefore be read alongside speed, torque, temperature, and fluid-level or intake-pressure information. A weak flow response to increasing speed points toward a different adjustment than rising torque at a maintained flow rate; the combined trend is more informative than any single reading.

Managing Cooling During Production and Restart

Steam huff-and-puff wells operate across a changing temperature profile. Early-cycle oil may enter the pump relatively readily, while later cooling increases viscosity and makes both intake and upward transport more demanding.

Cooling affects both sides of the pumping process: less fluid may fill the cavities, while the fluid already being lifted encounters greater resistance. A speed setting suited to the warmer production stage can consequently become poorly matched to late-cycle conditions.

Shutdown creates another operating state. Cooled oil and accumulated solids can increase restart resistance, so restoring the previous running speed immediately may impose unnecessary load before flow has recovered.

A controlled speed ramp allows operators to observe whether torque rises together with recovering production. In an adjustable conical PCP, working clearance provides a second operating variable alongside speed, allowing the startup procedure to address the pump's fit as well as its rotational demand.

Balancing Clearance, Torque, and Wear

Rotor–stator clearance influences the balance between pressure retention and resistance in an all-metal PCP. A larger gap permits more internal backflow, while a smaller gap improves pressure retention but provides less tolerance for dimensional changes or particles passing through the pump.

Thermal cycling changes component dimensions, with the operating clearance depending on relative expansion and temperature distribution. Sand introduces additional wear and obstruction risks, making a fixed working fit harder to maintain across changing production conditions.

Conical geometry allows controlled axial rotor movement to change the effective clearance. This provides a way to preserve pressure retention during production and introduce additional clearance when an approved startup or recovery procedure requires it.

When an All-Metal Conical PCP Is a Suitable Option

Connect Material, Geometry, and Control

These operating challenges explain why pump material, adjustable geometry, and surface control should be considered together. All-metal construction addresses thermal exposure, axial rotor positioning changes the working clearance, and the drive executes the required speed and position adjustments.

For the shallow-to-medium-depth applications addressed by HXBS artificial-lift systems, the value lies in coordinating those functions across the production cycle. The objective is to respond to changing fluid mobility and mechanical resistance while maintaining useful output.

The IntelliCPCP® all-metal conical PCP system combines the FERROXIS® pump with controlled lifting, a surface drive, and monitoring. DynaRL® supplies rotation and axial movement, translating the pump's adjustable geometry into an operating function available at the surface.

Monitoring completes that connection by showing how production responds to adjustment. Changes in torque, speed, pressure, and output help operators judge whether a setting is improving fluid delivery or adding load without a useful production gain.

Define the Application Fit

The application fit is strongest where the well can supply the intended rate and the principal operating difficulties arise from changing viscosity, thermal cycling, or manageable solids. Rod-and-tubing geometry, pressure requirements, and drive capacity must support the same operating envelope.

Where the main bottleneck is inadequate inflow, completion damage, or persistent solids accumulation, the production plan should address that restriction alongside lift selection. Increasing displacement alone does not resolve a limitation upstream of the pump.

For artificial lift for heavy oil recovery, performance should therefore be judged across the producing cycle. Sustained output, time on production, and intervention frequency provide a more useful comparison than the initial rate immediately after thermal stimulation.

Field Case: Shallow Extra-Heavy Oil Production in Nanyang

At the Nanyang shallow extra-heavy oil well, we applied an all-metal conical PCP system to a nitrogen–steam cyclic huff-and-puff operation with a pump setting depth of 453 m. The well faced cooling-related intake difficulty, rod–tubing wear, and sand plugging.

As production temperature declined, increasingly viscous oil became harder to draw into the pump. Despite the shallow setting, poor fluid mobility and solids created a demanding lifting duty and interrupted production.

Our approach combined adjustable pump clearance with injection–production integration. Injection–production integration addressed transitions between operating stages, while adjustable clearance provided a means of responding to changing fluid mobility and pump restrictions.

What to Check Before Selecting the Lifting System

The operating questions above translate into five selection checks. Each should establish the required operating range, the available production capacity, or the response needed when conditions change.

1. Establish the Operating Viscosity Range

Obtain viscosity measurements at representative production and restart temperatures, recording whether the sample is degassed crude, live oil, or a produced mixture. Use the resulting viscosity–temperature relationship to identify when cooling is likely to become a production constraint.

1. Match Displacement to Available Inflow

Set the intended pumping rate against the well’s fluid supply and expected cavity filling. Review the flow response to speed changes so that additional displacement remains connected to useful output.

1. Confirm Mechanical Capacity

Assess the drive and rod string against both steady production and restart loads. Include pressure demand, viscous resistance, and well geometry rather than sizing the system from average electrical consumption alone.

1. Define Operating Adjustments and Protection

Specify how speed and clearance will be adjusted as the well cools or resistance increases. Establish protection limits and clear responses to rising torque, falling output, and suspected solids accumulation.

1. Compare Equivalent Production Periods

Track sustained oil production, electricity per unit of output, downtime, and intervention frequency across comparable thermal stages. This shows whether an adjustment improves the producing cycle rather than only a short test period.

Conclusion: Match the Lifting System to the Production Cycle

Artificial lift for heavy oil recovery at 20,000 mPa·s @ 50°C requires adequate pump filling, sufficient torque, and suitable working clearance as the well cools. In shallow-to-medium-depth wells, coordinating these variables determines whether production can remain sustainable across the operating cycle.

Share your well depth, viscosity–temperature data, target production rate, and current operating challenges through our engineering inquiry form. Our engineers will contact you to discuss your well conditions, assess the application fit, and outline the next steps for lift-system selection.