The National Academy of Engineering (NAE) pointed to the need for designing blowout preventers (BOPS) that operate “under all foreseeable conditions.”
Despite numerous past warnings of potential failures of BOP systems, both industry and regulators had a “misplaced trust” in the ability of BOP systems to act as fail-safe mechanisms in the event of a well blowout, according to a new report from the National Academy of Engineering and the National Research Council.
The report -- Macondo Well-Deepwater Horizon Blowout: Lessons For Improving Offshore Drilling Safety -- recommended the redesign and rigorous testing of BOP systems in the dynamic conditions that occur during a blowout.
The study, which was sponsored by the U.S. Department of the Interior, pointed to multiple contributors to the accident. The lack of effective safety management among the companies involved in the disaster is evident in the multiple flawed decisions that led to the blowout and explosion. Regulators also failed to exercise effective oversight.
Despite the challenging geological conditions, there were alternative techniques and processes that were available that could have been used to prepare the exploratory well safely for temporary abandonment, the report stated.
Several signs of an impending blowout were missed by management and crew, resulting in a failure to take action in a timely manner, the report emphasized.
Regarding the BOPs, the report noted that the equipment was invented by Cameron Iron Works in 1922. The pre-publication copy of the report said, “The BOP used with the Deepwater Horizon was part of its TL series, based on the ram-type BOP design, which has matured and evolved over the years. In the absence of regulatory demand, the evolution of this expensive and long-lived piece of equipment appears to have been limited.
“However, advances in well-drilling technology, which allowed operation at greater water depths, presented a substantial challenge to the reliability of this basic BOP design. As other technological aspects of deepwater drilling continue to move forward, there is a need to improve BOP reliability,” the report continued.
For example, it is almost impossible for conventional blind-shear rams to sever tool joints, yet 5% to 8% of the drillstring consists of tool joints.
The report provides a detailed forensic analysis of the BOP. One finding was that when the blind-shear ram was activated, it was unable to center the drill pipe in its blades, which were a combination of straight and “V” blades. This combination has been shown to be inferior to the double-V blade geometry. Because the blind-shear rams did not fully span the BOP annulus, a mashed segment of pipe was caught between the rams and prevented the rams from closing, and thus these were unable to seal.
One of the recommendations in the pre-publication report noted, “BOP systems should be redesigned to provide robust and reliable cutting, sealing and separation capabilities for the drilling environment to which these are being applied and under all foreseeable operating conditions of the rig on which these are installed.
“Test and maintenance procedures should be established to ensure operability and reliability appropriate to the environment of application. Furthermore, advances in BOP technology should be evaluated from the perspective of overall system safety,” the report continued.
Proper training in the use of BOP systems in the event of an emergency is also essential. And while BOP systems are being improved, industry should ensure timely access to demonstrated capping and containment systems that can be rapidly deployed during a future blowout, the report said.
The "system safety" approach to anticipating and managing possible dangers at every level of operation was heavily emphasized by the NAE. The committee also recommended that an enhanced regulatory approach should combine strong industry safety goals with mandatory oversight at critical points during drilling operations.
"The need to maintain domestic sources of oil is great, but so is the need to protect the lives of those who work in the offshore drilling industry as well as protect the viability of the Gulf of Mexico region," said Donald C. Winter, former secretary of the Navy, professor of engineering practice at the University of Michigan, and chair of the committee that wrote the report. "Industry and regulators need to include a factual assessment of all the risks in deepwater drilling operations in their decisions and make the overall safety of the many complex systems involved a top priority."
The report also laid out a chain of command, in effect, for drilling wells offshore. Operating companies should have ultimate responsibility and accountability for well integrity. The drilling contractor should be held responsible and accountable for the operation and safety of the offshore equipment. Both industry and regulators should significantly expand the formal education and training of personnel engaged in offshore drilling to ensure that they can properly implement system safety. Guidelines should be established so that well designs incorporate protection against the various credible risks associated with the drilling and abandonment process. In addition, cemented and mechanical barriers designed to contain the flow of hydrocarbons in wells should be tested to make sure they are effective, and those tests should be subject to independent, near real-time review by a competent authority, the report emphasized.
Regulators should identify and enforce safety-critical points that warrant explicit regulatory review and approval before operations can proceed.
The regulating agencies came under scrutiny also. The report pointed out that offshore drilling operations are currently governed by a number of agencies, sometimes with overlapping authorities. The U.S. should make a single government agency responsible for integrating system safety for all offshore drilling activities.
Reporting of safety-related incidents should be improved to enable anonymous input, and corporations should investigate all such reports and disseminate lessons learned to personnel and the industry as a whole.
The study was sponsored by the U.S. Department of the Interior. Pre-publication copies of Macando Well-Deepwater Horizon Blowout: Lessons for Improving Offshore Drilling Safety are available from the National Academies Press by telephone at 202-334-3313 or 1-800-624-6242 or on the Internet at http://www.nap.edu. The final report is available for purchase on the NAE website.
Contact the author, Scott Weeden, at email@example.com.