ESP System Design Overview
Introduction
Electric Submersible Pumps (ESPs) are centrifugal pumping systems deployed downhole to lift reservoir fluids to the surface. ESPs are the workhorse of high-volume artificial lift, handling flow rates from a few hundred to over 100,000 barrels per day.
An ESP system provides:
- High production rates -- the widest operating range of any artificial lift method
- Reliable long-term performance -- modern systems achieve run lives exceeding 5 years
- Adaptability -- variable speed drives enable rate optimization
- Offshore applicability -- compact surface footprint
When to Use ESP
ESP vs. Other Artificial Lift Methods
| Method | Rate Range (BFPD) | Depth Limit (ft) | Gas Tolerance | Best Application |
|---|---|---|---|---|
| ESP | 200 - 100,000+ | 15,000 | Moderate | High-rate, high-volume wells |
| Rod Pump | 5 - 5,000 | 16,000 | Good | Low-to-moderate rate, shallow-to-deep |
| Gas Lift | 200 - 50,000 | 18,000 | Excellent | Gassy wells, deviated wells |
| PCP | 5 - 4,500 | 6,000 | Good | Heavy oil, sandy production |
| Plunger Lift | 1 - 200 | 19,000 | Excellent | Low-rate gas wells with liquids |
| Jet Pump | 300 - 15,000 | 20,000 | Good | Remote, subsea, hostile environments |
ESP Selection Criteria
ESP is typically the preferred method when:
- High rates are required (> 1,000 BFPD)
- Reliable power supply is available
- Free gas at pump intake is manageable (< 30-40% by volume without gas handling)
- Well deviation does not prevent installation
- Fluid viscosity is below approximately 200 cP at pump intake conditions
ESP may not be suitable when:
- Produced gas volumes are very high (GLR > 2,000 scf/STB without gas separation)
- Bottomhole temperatures exceed motor ratings (> 350-400 F)
- Well access for workover is severely limited
- Very low rates (< 200 BFPD) are expected long-term
ESP System Components
Component Stack
Component Summary
| Component | Function | Key Sizing Parameter |
|---|---|---|
| Pump | Generates head to lift fluid | Number of stages, head per stage |
| Motor | Drives the pump shaft | Horsepower, voltage, amperage |
| Seal / Protector | Isolates motor, equalizes pressure | Matches motor series |
| Intake / Gas Separator | Fluid entry, gas separation | Gas volume fraction at intake |
| Cable | Delivers power from surface to motor | Voltage drop, amperage capacity |
| VSD | Controls motor speed | Frequency range (30-90 Hz) |
| Transformer | Steps up voltage for downhole motor | Motor voltage rating |
Available Calculation Categories
Pump Performance
Calculate pump staging, total dynamic head, horsepower, and efficiency.
| Calculation | Description |
|---|---|
| Total Dynamic Head (TDH) | Net head the pump must generate |
| Number of stages | Stages required for target head |
| Hydraulic horsepower | Power transferred to the fluid |
| Brake horsepower | Shaft power required at pump |
| Pump efficiency | Ratio of hydraulic to brake HP |
| Operating range | Head-capacity curve evaluation |
Full Documentation: ESP Pump Performance
Gas Handling
Evaluate free gas effects and gas separator requirements at pump intake.
| Calculation | Description |
|---|---|
| Free gas at intake | Gas volume at pump suction conditions |
| Void fraction | Gas volume fraction in the mixture |
| Mixture density | Gas-liquid mixture density |
| Separator efficiency | Gas separator removal effectiveness |
| Turpin/Dunbar factors | Gas handling correction factors |
Full Documentation: ESP Gas Handling
Viscosity Corrections
Correct pump performance curves for viscous fluid effects.
| Calculation | Description |
|---|---|
| Correction factors | Head, efficiency, rate corrections |
| Viscous head | Derated head per stage |
| Viscous efficiency | Reduced efficiency |
| Viscous rate | Adjusted flow capacity |
Full Documentation: ESP Viscosity Corrections
Motor and Cable Sizing
Select motor horsepower and cable size for the installation.
| Calculation | Description |
|---|---|
| Required HP | Motor horsepower for pump load |
| Motor amperage | Operating current draw |
| Load factor | Motor loading percentage |
| Cable voltage drop | Voltage loss along cable length |
| Cable size selection | Minimum cable gauge for amperage and voltage drop |
| Power loss | Energy dissipated in cable |
Full Documentation: ESP Motor and Cable Sizing
System Design Workflow
Step-by-Step ESP Sizing
Key Design Parameters
Typical Operating Ranges
| Parameter | Typical Range | Units |
|---|---|---|
| Production rate | 200 - 100,000 | BFPD |
| Pump setting depth | 3,000 - 15,000 | ft |
| Total dynamic head | 2,000 - 12,000 | ft |
| Motor HP | 15 - 1,000 | HP |
| Motor voltage | 460 - 4,000 | V |
| Cable length | 3,000 - 15,000 | ft |
| Bottomhole temperature | 100 - 400 | F |
| Fluid viscosity (at intake) | 0.5 - 200 | cP |
| Free gas at intake | 0 - 30 | % (without gas handler) |
Critical Design Checks
| Check | Criterion | If Violated |
|---|---|---|
| Pump operating range | Within 80-120% of BEP rate | Select different pump or adjust rate |
| Motor loading | 70-110% of nameplate HP | Resize motor |
| Cable voltage drop | < 5% of motor nameplate voltage | Increase cable size |
| Gas void fraction | < 15-25% at intake (pump dependent) | Add gas separator or set pump deeper |
| Casing clearance | ESP OD < casing ID with margin | Select smaller series equipment |
| Temperature | BHT < motor rating | Use high-temperature motor |
Related Documentation
ESP Detailed Topics
- ESP Pump Performance -- Head-capacity curves, staging, efficiency, and BEP
- ESP Gas Handling -- Free gas, void fraction, separator efficiency
- ESP Viscosity Corrections -- Turpin and Stepanoff correction methods
- ESP Motor and Cable Sizing -- Motor HP, cable voltage drop, power loss
Supporting Analysis
- Well Flow Overview -- Inflow performance for determining pump intake pressure
- PVT Overview -- Fluid property correlations for ESP design inputs
- Pipe Flow Overview -- Tubing pressure drop calculations
References
Takacs, G. (2009). Electrical Submersible Pumps Manual: Design, Operations, and Maintenance. Gulf Professional Publishing.
Lea, J.F., Nickens, H.V., and Wells, M.R. (2008). Gas Well Deliquification, 2nd Edition. Gulf Professional Publishing.
Brown, K.E. (1984). The Technology of Artificial Lift Methods, Vol. 2b. PennWell Books.
Clegg, J.D., Bucaram, S.M., and Hein, N.W. (1993). "Recommendations and Comparisons for Selecting Artificial-Lift Methods." Journal of Petroleum Technology, 45(12), pp. 1128-1167. SPE-24834-PA.
Centrilift (Baker Hughes). (2008). Submersible Pump Handbook, 9th Edition. Baker Hughes.