Maximum Length of Drillpipe for a Specific Bottomhole Assembly Formula
Maximum Length of Drillpipe for a Specific Bottomhole Assembly calculates maximum drillpipe length for drillstring and rig mechanics workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (T, f, MOP, W_b, BF, W_d) are known and the assumptions behind the cited drillstring and rig mechanics 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, L_m equals 10,025.641026 ft.
450000
0.8
50000
80000
0.85
19.5
Inputs
T
lbTensile strength of pipe
f
dimensionlessSafety factor
MOP
lbMargin of overpull
W_b
lbBottomhole assembly weight in air
BF
dimensionlessBuoyancy factor
W_d
lb/ftDrillpipe weight in air
Outputs
L_m
Maximum drillpipe length
T
Tensile strength of pipe
f
Safety factor
MOP
Margin of overpull
W_b
Bottomhole assembly weight in air
BF
Buoyancy factor
W_d
Drillpipe weight in air
Source and review
reviewedFormulas and Calculations for Drilling, Production and Workover, Lapeyrouse, N.J. (2002)
Lapeyrouse, N.J. 2002. Formulas and Calculations for Drilling, Production and Workover, 2nd Edition, Gulf Professional Publishing, Page 43.