What Is The Drill Pipe Slip Crushing Effect
Slips exert hoop compression on the Drill Pipe which can deform the pipe if conditions are unfavorable. In this article we shall learn the drill pipe slip crushing formula and calculations.
A unit tensile stress St from hanging weight will result in a hoop stress Sh that is a function of many factors such as slip length, coefficient of friction between slips and bowl, pipe diameter and others. Based on that there was a term developed which is the slip crushing formula constant and it is defined for a given set of conditions as the ratio Sh/St. We have listed below a variety of Slip crushing calculations constants depending on many conditions.
A coefficient of friction of 0.08 between slips and bowl is normally used. If the pipe is not stuck, the maximum tension carried by the slips is the working load, Pw, which is the buoyed weight of the Drill Pipe and Bottom Hole Assembly BHA. So that in order to prevent any deformation of the pipe, the working load Pw times the crushing constant should be less than 0.8Y, or
I suggest for you to read more about this subject especially in deep water. I also have found a good paper related to our subject, it is called Advanced Slip Crushing Considerations for Deepwater Drilling. Off course, if you are unable to pay for it, you can use SCI-Hub services.