Chapter 6

Types of Free Point Tools


The free point tool run on electric line to determine stress and strain in a stuck drill string, casing string, or tubing string has three different configurations. The three different anchoring mechanisms transmit a stress or strain, over-pull, or torque to a strain gauge, which in turn sends various levels of current to the surface for interpretation. These anchors are knives, magnets, or adjustable bow springs. The commonly used configuration is the knife type, as it anchors into the inner diameter with a positive engagement.


Drill pipe stretch table

Free point constant

Set-down and slack-off weights

Stretch constant

Stretch graphs

Tubing stretch table

The free point tool run on electric ...

Get The Guide to Oilwell Fishing Operations, 2nd Edition now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.