Blowout During Workover
Effective Date: 6/12/1978
 | Minerals Management Service Gulf of Mexico OCS Region |
Notice No. 070
June 12, 1978
OCS Operations Safety Alert
Blowout During Workover
A well blew out of control during workover operations. The well apparently swabbed in while coming out of the hole with a perforation wash tool on a 2-inch work string. Twelve joints (360 feet) of pipe and the wash tool were still in the hole when the well began to flow. The wash tool O.D. was approximately full bore of the production casing. The hole had been filled every five (5) stands while pulling the pipe, but no attempt had been made to determine how much fluid the hole was taking.
A safety valve was installed in the work string and the blowout preventer was closed to control the flowing gas, water, and sand, but the valve would not close; it was stuck in the open position. Subsequent investigation indicated that the safety valve had been used as a control valve while washing perforations with a gelled brine water prior to starting out of the hole and sand was in the working parts of the valve. This could have been responsible for the valve failure.
To prevent a recurrence of this type of accident, the following actions can be taken:
1. Mud monitoring equipment be installed and used on all workover operations where pipe is tripped.
2. Safety valve should not be used for any purpose other than well control when needed.
3. Safety valve should be checked, closed and opened, before starting out of the hole to insure dependability.
[signed] D.W. Solanas
Oil and Gas Supervisor
Field Operations
Gulf of Mexico Area