Drilling EngineeringDrilling Hydraulics
Annular Capacity - bbl/ft Formula
Annular Capacity - bbl/ft calculates annular capacity for drilling hydraulics workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (D_h, D_p) are known and the assumptions behind the cited drilling hydraulics relationship match the engineering case being checked.
Assumptions
- Input values are representative for the well, reservoir, fluid, or equipment case being evaluated.
- The declared units match the field-unit constants used in the formula.
- The cited formula applies to the selected petroleum engineering workflow.
Limitations
- The calculation does not replace a full engineering model or operating procedure.
- Accuracy depends on the source correlation, assumptions, input quality, and unit consistency.
Common mistakes
- Mixing unit systems without converting the inputs.
- Using default example values as field recommendations.
- Applying the formula outside the source assumptions.
Default example
Using the default inputs, AC_bbl equals 0.045901 bbl/ft.
D_hin
8.5
D_pin
5
Inputs
D_h
inHole or Casing Inside Diameter
D_p
inPipe Outside Diameter
Outputs
AC_bbl
bbl/ft
Annular Capacity
D_h
in
Hole or Casing Inside Diameter
D_p
in
Pipe Outside Diameter
Source and review
reviewedLapeyrouse, N.J. 2002. Formulas and Calculations for Drilling, Production and Workover, 2nd Edition, Page 12.
Source