Annular capacity, abbreviated as AC, also called annular volume, is used to determining the volume of drilling fluids that can be held in the annular space between the drill string (casing) and the wellbore.
Annular Capacity Index
Annular Capacity (\(bbl/ft\)) formula
|
| \( AC \;=\; ( D_h^2 - D_{pod}^2 ) \;/\; 1029.4 \) |
| Symbol |
English |
Metric |
| \( AC \) = annular capacity |
\(bbl \;/\; ft\) |
- |
| \( D_h \) = drill hole size |
\(in\) |
- |
| \( D_{pod} \) = casing / drill pipe OD |
\(in\) |
- |
Annular Capacity (\(gal/ft\)) formula
|
| \( AC \;=\; ( D_h^2 - D_{pod}^2 ) \;/\; 24.51 \) |
| Symbol |
English |
Metric |
| \( AC \) = annular capacity |
\(gal \;/\; ft\) |
- |
| \( D_h \) = drill hole size |
\(in\) |
- |
| \( D_{pod} \) = casing / drill pipe OD |
\(in\) |
- |
Annular Capacity (\(m^3/m\)) formula
|
| \( AC \;=\; ( D_h^2 - D_{pod}^2 ) \;/\; 1,273,240 \) |
| Symbol |
English |
Metric |
| \( AC \) = annular capacity |
- |
\(m^3 \;/\; m\) |
| \( D_h \) = drill hole size |
- |
\(mm\) |
| \( D_{pod} \) = casing / drill pipe OD |
- |
\(mm\) |
Annular Capacity (\(l/m\)) formula
|
| \( AC \;=\; ( D_h^2 - D_{pod}^2 ) \;/\; 1,273.24 \) |
| Symbol |
English |
Metric |
| \( AC \) = annular capacity |
- |
\(l \;/\; m\) |
| \( D_h \) = drill hole size |
- |
\(mm\) |
| \( D_{pod} \) = casing / drill pipe OD |
- |
\(mm\) |
