Cutting off a Drilling Line: Safe Procedures
For many years drilling contractors have extended the life of their drilling lines by moving the areas of wear toward the drum to be cut off. The proper time to slip or cut off line on the drum end varies on different rigs.
The crews should remember whatever cut-off procedure they are using, visual inspection should come first. If the line becomes too badly worn, it should be cut off or changed when noticed. In preparation for cutting (slipping) the drilling line, employees should be aware of the potential hazards, including but not limited to:
- Fall from height: wear proper fall protection (full body harness) and utilize 100% tie off.
- Hoisting personnel into the derrick may result in falls, caught in, caught between: use full body harness type boatswain’s chair (or work basket), use personnel hoisting procedures, be sure the winch operator has full view of the person being hoisted at all times. The winch operator must stay at winch at all times when a person is being hoisted, held in position, or lowered.
- Struck by: be aware of potential dropped from the derrick, stay out from below derrickman when he is tying off the blocks, take care when removing the drilling line form the drum, be aware of use of tools while tightening the clamps on the line (drum and dead line).
- Slip/Fall while removing drilling line from drum/rig floor: be aware of footing, keep deck clear of tripping hazards, use a rig floor winch to let the cut off line down from the rig floor.
- Miscommunication: hold a pre-job safety meeting to discuss each member’s responsibilities, assign a signal man for tasks that require hoisting operations.
When getting ready to cut off the drilling line, the traveling block should be hung in the derrick on block hanging line(s) that hang from the crown. The hanging line should be rated for the weight of the blocks plus an adequate safety factor (check with wire rope manufacturer).
The TIW valve should be installed in the drill pipe prior to hanging off the blocks and the elevators attached to the pipe in the hole.
The derrickman should get to the traveling block by means of the air hoist line with a boatswain’s chair (or derrick work basket). The driller should be at the master clutch. Once the derrickman has attached the hanging line(s) to the blocks, he should return to the drill floor. When removing the blocks hanging line(s) after the drill line is cut and slipped, the derrickman should utilize a boatswain’s chair and air hoist line to reach the hanging line(s). After he has disengaged the hang-line from the block, he should swing the hang-line to a man in the derrick corner to be secured. The man in the derrick who is to secure the hang-line should have fall protection harness and be secured to the derrick at all times. The derrickman should then return to the floor by the boatswain’s chair. The man that secured the hang-line should climb down the derrick ladder using a safe climbing device. He should never slide down the dead line.
- Remove the excess worn line from the drum and cutoff as planned. Always use a wire line cutter. Never use a hatchet or sharp tool. Wear eye protection (chipping goggles) in addition to this check.
- Clamp the drum end of the line back into the drum and tighten the drum clamp as tightly as possible.
- Loosen the clamps on the wire line anchor and slip through as much line as is needed to put the desired wraps on the drum. Care should be taken to ensure that the warps are tight and together.
- Tighten the wire line clamps on the anchor, pick up traveling block and remove the hanging line(s) from block. The hanging line(s) should be tied back in the corner of the derrick out of the way of the blocks and ready for use the next time the line is slipped or cut off.
- Recheck all clamps and position of line and start in hole with a safe drilling line.
- Reinstall the crown protection device if it was removed. Adjust as necessary to stop the blocks as required.
- Reinstall the guard on the front of the drawworks.
- Reinstall the weight indicator sensor on the dead line and remove the TIW valve.