Lifting-lowering mechanically operated test tools, catalog page 50
Safety Joint
Coarse-thread safety joint for recovering the string above a stuck packer
Description
This safety joint is a safety tool for drill stem testing. It is used when the packer or sieve tube is stuck and the jar cannot free it: the tools and formation data above the joint are recovered. After release, a fishing tool is run, engages the safety joint thread, and the lower string can be pulled out.
Features
- Consists of an upper pin section and a lower box section
- Special coarse thread with loose fit and coarse pitch between the two sections allows quick connection
- When the joint is made up, the reverse-slope shoulder locks, so the interference-fit threads bear securely and the two sections form a rigid body
