Annular Capacity Between Casing and Multiple Strings of Tubing Formula
Annular Capacity Between Casing and Multiple Strings of Tubing calculates annular capacity for drilling hydraulics workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (D_i, T_1, T_2) 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, C_a equals 0.034091 bbl/ft.
7
2.875
2.375
Inputs
D_i
inCasing or Hole Inside Diameter
T_1
inTubing String 1 Outside Diameter
T_2
inTubing String 2 Outside Diameter
Outputs
C_a
Annular Capacity
D_i
Casing or Hole Inside Diameter
T_1
Tubing String 1 Outside Diameter
T_2
Tubing String 2 Outside Diameter
Source and review
reviewedFormulas and Calculations for Drilling, Production and Workover, Lyons, W.C., Carter, T., Lapeyrouse, N.J. (2012)
Lyons, W.C., Carter, T., and Lapeyrouse, N.J. 2012. Formulas and Calculations for Drilling, Production and Workover, 3rd Edition, Gulf Professional Publishing, Page 15.