Stuck Point Depth – Audit
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Stuck pipe, release 1, issued 11 April 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 depth of stuck point from stretch data.
Pipe OD and ID. L_Dpipe & L_dpipe
Pipe stretch. L_Δdp
Additional load. Fα
Enter a -ve value if axial compressive force
Click when modified to update the result.
Additional stress due to extra axial force;
Strain = stress / YM. Strain due to axial stress;
Strain = stretch / original length so original length = stretch / strain
Length of pipe above stuck point
Note – this is an estimate. Hole drag and pipe sticking over a length (eg packed off) rather than being stuck at a single point will affect the result. Use a free point indicator logging tool to find out the actual stuck pipe depth.
SUGGESTED METHOD OF GATHERING STRETCH DATA
If working the pipe in tension
- Slack off to the neutral weight indicator load (= rotating load if known, otherwise go below the normal up drag load). Do not lower enough to cock the jar.
- Pick up to the up drag load (the indicated load when moving the pipe upwards before getting stuck). Mark the pipe.
- Pick up to the maximum load you are comfortable with. Measure the distance that the pipe mark moved up.
- Input the difference in the loads and the pipe stretch into the worksheet and click Recalculate.
If working the pipe in compression
- Pick up to the neutral weight indicator load (= rotating load if known, otherwise go above the normal down drag load). Do not pick up enough to cock the jar.
- Lower to the down drag load (the indicated load when moving the pipe downwards before getting stuck). Mark the pipe.
- Lower to the minimum load you are comfortable with. Mark the pipe. Pick up and measure the distance between the marks.
- Input the difference in the loads and the pipe compression into the worksheet and click Recalculate.