production · lift
ESP Horsepower (Brake HP Required)
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Inputs
STB/d
ft
—
fraction
Description
Computes the brake horsepower an ESP pump must deliver at the shaft to lift a given flow rate against a given total dynamic head, correcting for fluid specific gravity and pump efficiency at the design point. Together with cable and motor losses (not included here), this sets the required ESP motor nameplate rating.
Variables
| Symbol | Unit | Description |
|---|---|---|
| BHP | hp | Brake Horsepower Required |
| Q | STB/d | Design total liquid flow rate through the pump. |
| TDH | ft | Total dynamic head at the design rate — run the ESP Total Dynamic Head (TDH) calculator first and carry its result in here. |
| SG | — | Specific gravity of the produced fluid at pump conditions (water = 1.0). |
| η | fraction | Pump efficiency at the actual design operating point, read from the manufacturer's pump curve — not the pump's nameplate best-efficiency-point (BEP) value unless the design point coincides with BEP. |
Assumptions
- SG represents the produced fluid's specific gravity at actual pump/flowing conditions, not stock-tank oil gravity alone
- Pump efficiency η is the efficiency at the actual design operating point on the vendor's pump curve, not the nameplate best-efficiency-point (BEP) value
- Fluid is effectively single-phase liquid at the pump — no viscosity correction to the pump's water-based performance curve is applied
Limitations
- This is pump brake horsepower only — it excludes cable losses and motor efficiency, so it understates the required surface electrical (kVA) input; a separate motor/cable sizing step is required
- Does not apply a viscosity correction — for viscous fluids, a centrifugal ESP's head/efficiency curve derates versus its water-based rating, which this calculator does not model
- The 135,636 constant is exact for the physical/arithmetic derivation shown above, but industry references commonly round it to "135,000"; a small (~0.5%) difference between the two is expected and immaterial at the tolerance this calculator targets
Use Cases
- → ESP motor sizing: Combine BHP with cable loss and motor efficiency to select an ESP motor's nameplate horsepower rating.
- → Stage-count cross-check: Cross-check a vendor's stage-by-stage horsepower summation (per-stage HP × stage count × SG) against this single-formula estimate.
Related Calculations
Region Notes
Permian Basin
Typical Wolfcamp/Bone Spring ESP installations (1,500-3,000 bpd, 4,500-7,500 ft TDH) size to roughly 75-250 BHP at 55-65% design-point efficiency, before motor/cable losses.
References
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