Module 3: Electrical Submersible Pumps (ESP)

High-volume lift with downhole centrifugal stages, seal section, motor & power system.

⏱ 55–70 minutes🎯 Intermediate🎁 Free

🎯 Learning Objectives

  • Explain ESP system components and how they interact under downhole conditions.
  • Select an appropriate ESP configuration for gas, deviation, and intake submergence.
  • Estimate ESP head/HP and recognize limits (voltage drop, motor load, cooling).
  • Apply field practices to mitigate gas interference, solids, and thermal risks.

📘 Key Terms

Stage head Gas handler Seal section BD configuration Shroud

📎 Prerequisite

Module 1 — fundamentals & Module 2 — rod pumping basics
Time: ~60–70 min Level: Intermediate Format: Reading + figures + quiz

ℹ️ What & Why

ESPs are high-rate artificial-lift systems: stacked centrifugal stages add head, a seal section equalizes pressure and carries thrust, and a downhole motor provides power. ESPs thrive in medium-to-high productivity wells where electrical power and cooling are available.

⚙️ Principles

  • Each stage adds head (ΔP); total head ≈ stages × head_per_stage.
  • Hydraulic horsepower ≈ Q × ΔP / 1714 (US units). Add losses to size brake/motor HP.
  • Motor cooling relies on intake flow; submergence matters.
  • Free gas reduces head and can cause surging—manage with separation or gas handlers.

🧩 Major Components

  • Pump stages (mixed/centrifugal) sized for head & rate at downhole conditions.
  • Seal section (protector) for pressure equalization, thrust bearing, oil expansion.
  • Motor (induction/PMSM) rated for temperature, voltage drop, and load.
  • Intake (standard, gas-handler, or separators) & discharge head.
  • Power system: flat cable, pothead, downhole gauges, VSD at surface.

📏 Operating Considerations

💡
Field Tip
Plot operating point on the pump curve at downhole conditions (rate, viscosity, gas). Avoid the left (recirculation) and far-right (run-out) extremes.
⚠️
Common Pitfall
Under-estimating voltage drop or motor temperature margin leads to premature trips. Check cable size, well depth, and VSD settings.

🧱 Configuration Patterns

Standard ESP Layout

Baseline arrangement with intake above motor and discharge up the tubing. Suited for most vertical and moderate-deviation wells with sufficient intake submergence and manageable free gas.

Standard ESP layout with intake above motor and discharge to tubing
Figure 3.1 — Standard ESP layout.

ESP with Gas Handler / Degasser

Adds a gas-handling stage or rotary separator ahead of the pump to process free gas. Recommended when GLR at intake is significant (e.g., 300–1000 scf/bbl) to stabilize head and reduce surging.

ESP system schematic with gas handling or degasser stage
Figure 3.2 — ESP with gas-handling/degasser stage.

Bottom-Discharge ESP

Discharges below the motor to improve cooling flow around the motor or to accommodate special completion constraints. Useful where intake submergence is tight or vertical flow past the motor is needed.

Bottom discharge ESP configuration showing flow past motor
Figure 3.3 — Bottom-discharge ESP configuration.

Shrouded ESP

A shroud forces cross-flow past the motor for cooling and can help separate free gas or solids before entering the intake. Preferred in deviated wells, low-intake-head situations, or when inflow is from above.

ESP with shroud to force cooling flow and aid gas/solids management
Figure 3.4 — Shrouded ESP configuration.

Subsea / Seabed ESP

Seabed or subsea-tree ESPs shorten lift length, reduce riser backpressure, and enable high-rate offshore developments. Requires topside power/VSDs and specialized wet-connects and retrieval systems.

Subsea ESP installation concept
Figure 3.5 — Subsea ESP installation concept.

✅ Quick Knowledge Check

1) The most direct mitigation for high free gas at the ESP intake is…
Gas handlers reduce free gas entering stages and stabilize head.
2) Bottom-discharge layouts are primarily used to…
Discharging below the motor promotes cooling flow past the motor body.
3) A shroud is most helpful when…
Shrouds force crossflow for cooling and can aid separation when inflow is from above.

🧾 Summary & Takeaways

  • ESPs deliver high head by stacking centrifugal stages; motor cooling depends on intake flow.
  • Configuration matters: standard for clean conditions; gas-handler, BD, or shroud to manage gas/cooling.
  • Check pump curves at downhole conditions and stay within the recommended operating range.
  • Account for voltage drop, temperature, and submergence margins in design and operations.

➡️ What’s Next

Up next: Module 4 — Progressive Cavity Pumps (PCP)
Tip: gather your field’s GLR and intake submergence data to practice config selections.
Go to Module 4 →
Last updated: Aug 2025 • Author: Atlas ESP Academy
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