production · tubing performance
Reynolds Number (Tubing Flow)
click formula to derive ↑
Inputs
lb/ft³
ft/s
in
cp
Description
Computes the standard Newtonian Reynolds number for single-phase fluid flow in production tubing, classifying the flow as laminar, transitional, or turbulent. Distinct from Drilling's own Reynolds Number calculator, which uses the Bingham-plastic rheology model appropriate to non-Newtonian drilling mud — production tubing flow (oil, water, or gas) is standard Newtonian fluid flow and uses the simpler classical form.
Variables
| Symbol | Unit | Description |
|---|---|---|
| NRe | — | Reynolds Number |
| ρ | lb/ft³ | Density of the flowing fluid at the conditions of interest. |
| v | ft/s | Fluid velocity in the tubing — run the Gas Velocity or Liquid Velocity calculator first and carry its result in here (see relatedCalcs). |
| d | in | Tubing internal diameter. |
| μ | cp | Viscosity of the flowing fluid at the conditions of interest. |
Assumptions
- The flowing fluid is Newtonian — oil, water, and gas at typical production tubing conditions all satisfy this; drilling mud (non-Newtonian, Bingham-plastic) does not, which is why Drilling's own Reynolds Number calculator uses a different formulation
- Single-phase flow — a genuinely multiphase (gas+liquid) stream requires a mixture-property treatment this classical form does not provide
- Density and viscosity are representative of the flowing fluid at the conditions of interest, not stock-tank or standard conditions
Limitations
- Single-phase only — does not apply directly to a multiphase (gas+liquid) stream without first defining appropriate mixture density and viscosity
- The 2,100/4,000 transition thresholds are standard textbook values, not a precise physical boundary — real transitional behavior can be somewhat pipe- and disturbance-dependent
- Velocity, density, and viscosity are treated as single representative values — properties that vary meaningfully along the tubing string (e.g., gas velocity increasing toward surface as pressure drops) require re-evaluation at each depth of interest
Use Cases
- → Flow regime classification: Determine whether tubing flow is laminar or turbulent before selecting an appropriate friction-factor correlation.
- → Friction factor input: Feeds directly into the Friction Factor (Haaland) calculator, which requires Reynolds number as an input.
Related Calculations
Region Notes
Global
Most producing wells operate turbulent (NRe well above 4,000) at typical tubing sizes and rates — laminar production tubing flow is unusual outside very low-rate, high-viscosity (heavy oil) wells.
References
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