Drill string · Drilling
Drilling Jars
A tool in the string that sharply increases the impact force to free a stuck tool or pipe.
What it does
Energy builds up in the string as it is pulled and is released suddenly when the jar fires, delivering an impact load to the stuck point.
Basics
| Types | Mechanical or hydraulic |
| Run on | Drill pipe, tubing, coiled tubing or slickline |
| Part of | Bottomhole assembly |
Common failures
- Stuck pipe that the jar cannot free
Troubleshooting
- Symptom
- Jarring does not free the pipe
- Likely cause
- Not enough energy reaching the stuck point
- What to check
- Review jar placement and the pull used to store energy