Inspection Detail

Inspection: 304471030 - Reliance Well Service, Inc.

Inspection Information - Office: Baton Rouge Area Office

Investigation Summary

Some employees were working on a Cardwell KB-250 oil-drilling rig (Serial Number 99), which was built in 1979 and placed in service in 1980. This drilling platform was a hybrid--a combination of a stationary drilling platform and ancillary equipment, and a well-servicing or work-over rig. The work-over rig was backed onto a tilting platform next to the drilling platform. The tilting platform was then leveled; the rig itself was leveled; and the derrick was raised into position and secured with guys. An employee changing room was located under the tilting platform. Leveling screw-jacks were located at four locations under the frame of the work-over rig. Two other screw-jacks were located at the rear of the rig, attached to the rear bumper. These screw-jacks were tightened up against the frame of the drilling platform, which in turn held the rig in place by friction alone. The crew was replacing pipe and had removed approximately 60 stands of pipe. Each stand was 90 ft in length and weighed approximately 1250 pounds, for a total of approximately 75,000 pounds. The rig had been operating for approximately 1 month. The crew began experiencing tight spots as they were pulling the pipe. Shortly before 8:00 p.m., the employees encountered a tight spot that would not allow any additional pipe to be taken out of the hole. They attempted many times to break through the blockage by pulling up on the pipe. They continued pulling until approximately 11:00 p.m., when one of the horizontal securing screw-jacks slipped off the friction pad. This caused the rig to tilt to the 1 o'clock position. It also caused the stands of pipe in the monkey board to shift and rotate. This removed the tension from all the guys except one, with the remaining guy supporting the rig and the pipe stands. When the rig tilted to one side, the crew evacuated to a safe area on the southeast side of the site, approximately 50 ft from the rig. They remained there until the supervisory personnel arrived at approximately 2:00 a.m. the next morning. The supervisory personnel inspected the rig to determine what steps needed to be taken to reposition and stabilize it. When the supervisory personnel went to the far side of the rig, two employees decided to go into the change room and retrieve their personal belongings from their lockers. The lean of the rig was directly over the door to the changing room. When they entered the room, the remaining guy (a 0.875-in. wire rope) broke, allowing the rig to fall. The two employees tried to get out, but Employee #1 was struck by part of the derrick as it fell. The other employee was able to get away from the rig with only minor injuries. Operations manuals for the hybrid oilrig were not available.

Keywords: DERRICK, COLLAPSE, OVERLOADED, EQUIPMENT FAILURE, GUY, STRUCK BY, OIL RIG, UNSTABLE POSITION