BSEE Issues Alert on DP System Failure

 

The U.S. Bureau of Safety and Environmental Enforcement (BSEE) has issued a Joint Safety Alert addressing a dynamic positioning (DP) incident involving an offshore supply vessel (OSV) which resulted in a loss of position while conducting a critical Outer Continental Shelf (OCS) activity.

The OSV was attached to a wellhead, lost position and severed the wellhead tree causing a lubricant release on the platform deck and to the environment. Immediately prior to the position loss, the OSV had multiple DP system alarms and failures, including loss of bow thruster and engine control. No attempt was made to identify or correct the causes of these failures and the operations continued.

 

At the time of the position loss, the OSV was being utilized to support pump and electric line equipment which was connected to the well at the time of the incident. Specifically, when the vessel lost position, the vessel operator was in the process of removing a downhole DX plug from the well via wireline. High pressure pump lines were also connected to the well, although actual pumping operations were not in progress. When the vessel lost position, the Christmas tree was sheared from the well because of the force exerted on it by virtue of the connected high pressure lines. Severe consequences were averted because a subsurface safety valve was activated and there was an absence of hydrocarbon flow from the well.

 

The OCS activity performed was critical due to the short time to terminate and the potential uncontrollable release of hydrocarbons from a well with known sustained casing pressure. The Coast Guard and the BSEE are issuing this joint Safety Alert because we share jurisdiction on the OCS and wish to highlight the importance of an OSV’s Safety Management System (SMS) and a leaseholder’s Safety and Environmental Management System (see Reference 1).

 

BSEE said this incident highlights the following critical issues:

 

Alarms: The Coast Guard and BSEE stress the importance of properly acknowledging and investigating all alarms, and taking immediate and positive corrective action prior to initiating or proceeding with any critical OCS activity.

 

SMS: The OSV was not required to and did not have an International Safety Management (ISM) Code certificate. The Coast Guard reminds OSV owners and operators that an effective SMS is essential to safe operations, particularly when those operations are critical OCS activities. Had the OSV implemented an effective SMS, as described in the ISM code, it likely would have:

 
Dynamic Positioning: The Coast Guard strongly recommends owners and operators of OSVs using DP to follow DP guidance provided in reference 3 (Marine Technology Society (MTS) DP operations guidance) when conducting critical activities on the U.S. OCS. See the applicable notice on this topic published in the Federal Register (77 FR 62247, October 12, 2012) for more details. Had this OSV followed the MTS DP operations guidance it likely would have:

 

Leaseholder/operator SEMS: BSEE strongly recommends leaseholders/operators consider Coast Guard recommendations for DP vessels when evaluating potential hazards and establishing/implementing contractor safe work practices in their SEMS program (see 30 CFR §§ 250.1911 and 250.1914). BSEE reminds leaseholders/operators of their critical role in ensuring safety and environmental hazards associated with contracted vessels on their lease are properly managed. For example, leaseholders/operators should ensure hazards associated with a loss of position by contracted DP vessels are analyzed and managed with appropriate contractor safe work practices.