Pipe Capacity
Internal volume of pipe per foot of length (barrels per foot).
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Example
D=4.276 in: C ≈ 0.01776 bbl/ft
How it works
This formula gives the internal volume held by one foot of pipe, expressed in oilfield barrels per foot. It comes from the cylinder volume relation V = πD²/4 multiplied by 12 inches per foot, then converted from cubic inches to barrels using 1 bbl = 9702 in³, which is why the constant 1029.4 appears in the denominator. Because volume scales with the square of diameter, even a small change in inside diameter has a noticeable effect on pipe capacity.
When to use it
Use this when estimating fluid volume in tubing, drill pipe, casing, or flowlines from their internal diameter. It is especially useful for displacement calculations, fill-up estimates, and planning circulating or pumping volumes.
Worked example, step by step
Given internal diameter D = 5.000 in Step 1: Square the diameter: D² = (5.000)² = 25.000 Step 2: Divide by 1029.4: C = 25.000 / 1029.4 Step 3: Compute the capacity: C ≈ 0.02428 bbl/ft Final answer: The pipe capacity is about 0.0243 barrels per foot.
Common mistakes to avoid
- Using outside diameter instead of internal diameter
- Forgetting that the result is per foot, not for the full pipe length
- Mixing units by entering diameter in millimetres or centimetres without converting to inches
Did You Know?
The 1029.4 constant converts square inches per foot into barrels — a staple of well-volume math.
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