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the hardness of each. It is not always possible to
have proper designs for both strings and prevent
the drill string being harder than the casing.
214 Copyright(c) 2005 by Ali Ghalambor & Boyun Guo 107 Bearing Load Considerations
Side force is caused by:
1. Doglegs in the wellbore.
2. Intervals of hole angle change.
3. The casing in a buckled state.
4. Effective weight of drill string hanging below the point of
Casing can be prevented from buckling by:
1. Not allowing sufficient room outside the casing for buckling
2. Insuring that the axial loading in the casing string, as used,
is algebraically greater than the stabilizing forces on the string.
215 Rate of Motion of Drillstirng to
The culprit that actually causes the casing to wear
is the frictional energy created at the point of
contact. The greater the rate of motion for a given
load, over an area of contact, the greater the
frictional energy generated.
In instances where wear is a major consideration,
downhole motors or turbines can be used to
provide the rotational mo...
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This document was uploaded on 03/28/2014.
- Fall '14