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Casing and Multiple Strings of Tubing Flow Rate Formula and Calculator

Fluids Flow Design and Engineering
Hydraulic & Pneumatic Design Engineering
Pressure Vessel Pipes Design Engineering ASME

Annular Flow Capacity Between Casing and Multiple Strings of Tubing Formula and Calculator

Eq. 1
Annular capacity between casing and multiple strings of tubing, bbl/ft:

Ca =[ Dh2 - ( T12 + T22 + T32 ) ] / 1029.4

Eq. 2
Annular capacity between casing and multiple strings of tubing, ft/bbl:

Ca = 1029.4 / [ Dh2 - ( T12 + T22 + T32 ) ]

Eq. 3
Annular capacity between casing and multiple strings of tubing, gal/ft:

Ca = [ Dh2 - ( T12 + T22 + T32 ) ] / 24.51

Eq. 4
Annular capacity between casing and multiple strings of tubing, ft/gal:

Ca = 24.51 / [ Dh2 - ( T12 + T22 + T32 ) ]

Eq. 5
Annular capacity between casing and multiple strings of tubing, ft3/linft:

Ca = [ Dh2 - ( T12 + T22 + T32 ) ] / 183.5

Eq. 6
Annular capacity between casing and multiple strings of tubing, linft/ft3:

Ca = 183.35 / [ Dh2 - ( T12 + T22 + T32 ) ]

Where:
Ca = Annular capacity
Dh =Casing or Hole size ID (in.)
T1 = tubing No. 1
T2 = tubing No. 2
T3 = tubing No. 2

Example: Using three strings of tubing:

Dh = casing — 9-5/8 in. - 47 lb/ft ID = 8.681 in.
T1 = tubing No. 1 - 3-1/2 in. — OD = 3.5 in.
T2 = tubing No. 2 - 3-1/2 in. — OD = 3.5 in.
T3 = tubing No. 3 - 3-1/2 in. — OD = 3.5 in.

Annular capacity linft/ft3

Ca = 183.35 / [ 8.6812 - ( 3.52 + 3.52 + 3.52 ) ]

Annular capacity = 4.7487993 linft/ft3

Source:

Reference: Lapeyrouse, N. J., 2012, Formulas and Calculations for Drilling, Production and Workover, Third Edition

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