Margin of Overpull in Drillstring

Margin of overpull is additional tension to be applied when pulling the stuck drill string without breaking the tensile limit of the drill string. This is the difference between maximum allowable tensile load of drill string and hook load.

There are several factors when consider about the margin of over pull as listed below;

• Overall drilling conditions
• Hole drag
• Likelihood of getting stuck
• Dynamic loading

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