Progressing Cavity Pump (PCP) Artificial Lift Simulator
ISO 15136 Mechanics • Elastomer Swelling & Interference • Sucker Rod Combined Stress • Drive Motor Sizing
1. Wellbore & Produced Fluid State
2. Pump Geometry & Stator Elastomer
3. Sucker Rod String & Drive Head
Progressing Cavity Pump Downhole Rotor-Stator Engagement Visualizer
Downhole Hydraulics & Stator Elastomer Diagnostics
Governing ISO 15136 PCP Design Equations
Q_{theo} = V_{cavity} × N (m³/min) → η_{vol} = Q_{actual} / Q_{theo}
Q_{slip} ∝ (ΔP / n_{stages}) × (Clearance³ / μ_{fluid})
T_{hyd} = (V_{disp} × ΔP) / (2π) (N·m) | T_{total} = T_{hyd} + T_{fric,stator} + T_{rod,drag}
P_{motor} = (T_{total} × 2π × N / 60) / η_{drive} (kW)
σ_{tensile} = W_{axial} / A_{rod} | τ_{torsion} = (16 × T_{total}) / (π × d_{rod}³)
σ_{vm} = √( σ_{tensile}² + 3 × τ_{torsion}² ) ≤ 0.70 × SMYS_{rod}
5 Fatal Traps & Engineering Pitfalls
1. Dry Run Stator Elastomer Melt & Hysteretic Thermal Degradation
Operating a PCP without fluid inflow (e.g. gas locking or pumped-off well) strips away boundary lubrication between rotor and stator. Dry sliding friction generates over 220°C within 60 to 90 seconds. The molded nitrile elastomer reaches its reversion temperature, turns into a gummy black tar, and melts, completely destroying the stator.
2. Elastomer Swelling in High-Aromatic Diluent Causing Mechanical Lockup
Injecting naphtha or condensate diluents containing >15% aromatic hydrocarbons causes rapid solvent absorption into NBR stators, swelling the elastomer volume by 6% to 10%. The internal stator cavity closes around the steel rotor, transforming intended clearances into a crushing interference fit. Friction torque spikes beyond surface drive motor limits, stalling the well.
3. Explosive Sucker Rod Backspin & Surface Drive Braking Failure
When the drive head shuts down against a 1,200 m hydrostatic fluid head, the fluid column drives the PCP in reverse like a hydraulic turbine. The thousands of Joules of stored torsional strain in the sucker rod string uncoil violently, spinning the surface drive backwards at over 3,500 RPM. If the centrifugal brake slips or is undersized, the drive pulley explodes and threaded sucker rod couplings unscrew, dropping the rod string into the well.
4. Sand Scouring & Volumetric Slip Run Life Collapse
In heavy oil wells producing coarse quartz formation sand (>2 wt%), abrasive particles become trapped in the tight rotor-stator sealing lines. Squeezed sand grains gouge deep helical trenches through the chrome plating and tear strips of rubber out of stator lobes. Once internal slip channels form, backflow velocity accelerates erosion exponentially, dropping production to zero in under 60 days.
5. Rod String Harmonic Resonant Buckling & Tubing Casing Wear
Running sucker rods at speeds matching natural torsional or lateral harmonic frequencies induces severe helical rod buckling inside the tubing. High-contact normal forces grind rod couplings directly against the inner steel tubing wall. Without molded rod centralizers, the rotating rod cuts through 7-inch production tubing within 4 months, flooding the casing annulus with oil.