The safety joint (SJB) allows quick release of the test string if the string below the packer becomes stuck. The tool has a coarse thread to carry the string load and allow easy disengagement and re-engagement. The SJB is typically positioned on top of the packer and made up to the same torque as the other tools in the string. It is disengaged by left-hand torque. The shear pins in the tool maintain a consistent breakout torque regardless of wear and tear on the tool. The breakout torque is controlled to 950 ft.lbf by a shear pin. An adjusting ring keeps the right-hand torque from acting on the shear pin. The joint can be engaged by applying weight and rotating it slowly to the right. After disengagement, the retrieved pin is easily screwed back into a downhole box section with a suitable fishing assembly for retrieval of the stuck string.
Request More Information
|