Sucker Rod Pump SRP

Sucker Rod Pumping System Notes

Overview

  • The sucker rod pumping system is a widely used method in oil production, leveraging mechanical motion to lift fluids from wells.

Historical Background

  • In Use Since: 1850

  • Early rigs utilized wooden walking beams to drive sucker rods.

  • Performance Metrics:

    • Strokes: 10 strokes/min

    • Average Stroke Length: 15 inches

    • Subsurface Pump Diameter: 1 ¼ inch cast iron

    • Average Well Depth: 500 to 1000 ft

  • Equipment included band wheel and flat belt speed reducers.

Major Components of the Pumping System

Main Components

  • Sub-surface Pump: Pumps located below surface.

  • Sucker Rods: Steel rods that connect surface equipment to downhole pumps.

  • Surface Pumping Unit: Mechanism that converts rotary motion into linear motion.

Parts of Pumping Unit

  • Key Components:

    • Polished Rod

    • Flow Tee

    • Well Head

    • Celler Pit

    • Flow Line

    • Casing and Tubing

    • Sucker Rod String

    • Barrel, Plunger, Valves

Operating Principles

Pumping Mechanism

  • Prime Mover: Converts rotary motion into linearly directed forces.

  • Working Mechanics:

    • Polished Rod and Gear Reduction: Reduces the speed while increasing torque.

    • Motion Conversion: Rotary motion from the prime mover is transformed into linear motion through the sucker rod.

Pumping Cycle

  • Upstroke vs Downstroke:

    • Upstroke: Quick speed reduces leakage.

    • Downstroke: Slower speed to manage fluid transfer and reduce rod bowing.

Fluid Behavior During Operation

  • Gas Prominence (Upstroke): Leads to low-pressure forms in the pump's primary chamber, enabling fluid intake.

  • Gas Compression (Downstroke): High compressibility leads to multiple gas-liquid interactions and the potential for gas locking, where the pump fails to transfer fluids.

  • Fluid Pound Phenomenon: Hydraulic impacts when fluids load rapidly during pumping cycles. This creates a shock effect damaging the pumping system.

Fluid and Gas Pound Discussions

  • Gas Pound (G/Pound): Common in high gas oil ratio wells.

  • Fluid Pound (F/Pound): Occurs when the pump's chamber is not filled sufficiently.

  • Preventative Measures: Include appropriate valve spacing, slower speeds, and optimized pump designs to minimize shock loads.

Types of Pumps Used

Subsurface Pump Varieties

  • Insert Pumps: Effective in different configurations based on hold-down options (top or bottom).

  • Specialty Pumps: Such as two-stager types and hollow valve rods designed to reduce key issues like buckling and gas interference.

API Designation and Selection Criteria

  • Pump Classification: Includes criteria based on material, barrel specifications, and functionality.

  • Size Guidelines: Various tubing and plunger sizes based on casing diameter to optimize production rates and efficiency.

Monitoring and Troubleshooting Guidelines

  • Regular Maintenance: includes checking the polished rod position, lubrication levels, and overall system sounds.

  • Dynamometer Cards: Used for analyzing the performance of the system, helping determine efficiency and potential issues during operation.

Conclusion

  • The sucker rod pumping system remains a critical technique in oil extraction, requiring understanding of mechanical systems, fluid dynamics, and regular preventative measures to optimize performance and longevity.