Casing and Multiple Strings of Tubing Flow Rate Formula and Calculator

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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:

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

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

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

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

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

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

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

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

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

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

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

Where:
C_a = 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

C_a = 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