The Weatherford safety joint enables retrieval of tubing and drillstem test tools above the disconnect point should the tubing string become stuck in the wellbore at or below the packer. The safety joint provides a release point directly above the service packer in the event that the packer cannot be unset as planned, allowing retrieval of the downhole gauges and test tools and providing a means of fishing the packer and tailpipe assembly. In the event that the safety joint is released, an overshot can be run to reconnect the packer and tailpipe assembly to the work string. At this point greater overpull and jarring can be applied with the gauges and test tools removed from the string.
The safety joint is run on the test string directly above the packer and below the hydraulic jar. The string is released by applying righthand torque to break the shear screws in the safety joint, followed by 12 complete clockwise rotations to separate the tool. Up to six anneeled steel shear screws can be used, and the amount of torque required depends on the number of shear screws in place, with a maximum shearing torque at the tool of 6,000 lbf-ft (8.13 kN•m).
- Drillstem testing
- Production testing
- Perforating operations
Features, Advantages and Benefits
- The release is controlled by shear screws, avoiding possible damage to the tool string through application of excessive torque.
- Safety joint allows recovery of downhole memory gauges and, therefore, valuable recorded data.
- Full-bore ID of the safety joint facilitates unrestricted flow and access for well interventions.