Stuck Pipe Free Point from Pipe Stretch - Method 1 Formula
Stuck Pipe Free Point from Pipe Stretch - Method 1 calculates estimated free pipe length for drillstring and rig mechanics workflows in drilling engineering.
How engineers use this formula
Use this formula when the listed inputs (OD, ID, S, PF) 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, h_f equals 1,977.978064 ft.
5
4.276
12
80
Inputs
OD
inPipe outside diameter
ID
inPipe inside diameter
S
inMeasured pipe stretch
PF
1000 lbDifferential pull force
Outputs
h_f
Estimated free pipe length
fpc
Free point constant
S
Measured pipe stretch
PF
Differential pull force
OD
Pipe outside diameter
ID
Pipe inside diameter
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 74.
Source