The most severe wear occurs at the pick up points in the sheaves and at the lap points on the drum of the drawworks. Note,the pick up points are the points in the drilling line that are on top of the crown block sheaves or the bottom of the travelling block sheaves when the weight of the drillstring is lifted from its support in the rotary table during tripping operations. The lap points are the points in the drilling line where a new layer or lap of wire begins on the drum of the drawworks.
Drilling line need to be cut and slip at regular ton-miles intervals because it is believed that at that ton-mile,the lines would have been worn and continual usage might be dangerous
Quote Originally Posted by pet_spec View Post
Hey, guys

Can you please provide the answers for the following two quesitons:

1) Where are the critical wear points located on a drilling line? Illustrate your answer with a sketch ?
2) Explain, briefly, why a drilling line has to be slipped and cut at regular ton mile intervals?

Thanks.