Pipe Stretch – Audit
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Pipe stretch, release 1, issued 7 March 2010. AUDIT version.
This worksheet exists in two versions. They are identical apart from the way they are formatted. The Work version hides intermediate calculations and allows the user to see the results just below the inputs. This is useful for quick “what-if” games, changing various inputs to see what works best. The Audit version displays all intermediate calculations.
This worksheet will calculate the change in length of pipe due to a) it’s own weight when submerged in fluid, b) additional axial load (tension or compression) and c) a change in the average temperature.
psi/ftSG or kg/lppgkPa/mlb/ft3lb/bbl
Mud density. Jmudsg
Steel vertical length. L_Vsteel
Pipe OD and ID. L_Dpipe & L_dpipe
Average temperature change. TΔ
Enter a -ve value if the temperature drops
Additional load. Fα
Enter a -ve value if axial compressive force
Click when modified to update the result.
Entered values in SI units;
Constants and coefficients;
SG for steel
Youngs Modulus for steel
Steel coefficient of thermal expansion
Calculate steel SG – mud SG
Calculate volume of steel if 1 cm x 1 cm x length
Average force over the length = half the total force at the top. Calculate the force in Newtons arising from half the buoyant mass of steel
Stress = load / area. Average stress due to own weight;
Additional stress due to extra axial force;
Strain = stress / YM. Strain due to axial stress;
Thermal strain due to temperature change;
Strain = stretch / original length so stretch = strain x original length.
Total pipe length after strain
Original length of pipe
Length of pipe due to
axial and thermal strain