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Appendix C: Findings, Observations, and Recommendations
Pages 142-165

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From page 142...
... Department of Defense DOI U.S. Department of the Interior DNV Det Norske Veritas EDS emergency disconnect system LMRP lower marine riser package MODU mobile offshore drilling unit MUX multiplexer OIM offshore installation manager ppg pounds per gallon ROV remotely operated vehicle SEMS Safety and Environmental Management Systems VBR variable bore ram 1 This compilation was not presented in the prepublication version of this report, which was issued in December 2011.
From page 143...
... This would have had the unintended effect of leaving a tail slurry containing foamed cement in the shoe track at the bottom of the casing rather than leaving the heavy, un-foamed tail cement. Finding 2.5: Foamed cement that may have been inadvertently left in the shoe track would likely not have developed the compressive strength of the un-foamed cement, nor would it have had the strength to resist crush ing when the differential pressure across the cement was increased during the negative test.
From page 144...
... Observation 2.2: Had an attempt been made to bleed off the drill pipe pressure at the end of the negative test, the communication with the reser voir would likely have been discovered. Observation 2.3: The results of a variety of static tests of foamed cement mixed at 14.5 ppg and exposed to atmospheric pressure call into question the stability of the foam, because settling of cement and breakout of nitro gen were observed in these tests.
From page 145...
... Observation 2.6: The use of a production liner rather than the long string could have allowed for the use of a rotating liner hanger to improve the chances of good cement bonding; allowed for the use of a liner top packer to add a barrier to annular flow near the bottom of the well; allowed for the omission of the differential fill tube, which would remove a potential failure mechanism for the float collar; potentially made the negative test simpler to conduct and interpret; and configured the well to better control and repair a leak in the liner by leaving the well filled with drilling mud to a greater depth and by placing the drill pipe at a greater depth in the well during the test. Recommendations Summary Recommendation 2.1: Given the critical role that margins of safety play in maintaining well control, guidelines should be established to ensure that the design approach incorporates protection against the various credible risks associated with the drilling and completion processes.
From page 146...
... The BSR failed to sever the drill pipe and seal the well properly, and the EDS failed to separate the lower marine riser and the Deepwater Horizon from the well. Finding 3.2: The crew did not realize that the well was flowing until mud actually exited and was expelled out of the riser by the flow at 21:40.
From page 147...
... could have been destroyed. The growing fire indicates that the drill pipe was broken in the initial ex plosion and the fall of the traveling block could have allowed even more flow to escape up the drill string.
From page 148...
... Finding 3.14: The effect of closing the CSR on April 29, 2010, was to provide a new flow path exiting the severed drill pipe below the CSR and passing the CSR rams that were not designed to seal. Severe fluid erosion occurred past the CSR, with deep cuts made in the surrounding steel of the BOP housing itself, endangering the integrity of the housing.
From page 149...
... 2. While individual subsystems of various BOP designs have been studied on an ad hoc basis over the years, the committee could find no evidence of a reliability assessment of the entire BOP system, which would have included functioning at depth under precisely the condi tions of a dynamic well blowout.
From page 150...
... Observations Observation 3.1: In the confusion of an emergency such as the one on the Deepwater Horizon, it is not surprising that a drill crew would not take the time to determine whether a tool joint was located in the plane of the BSR or whether tension was properly maintained in the drill pipe. Observation 3.2: In terms of emergency procedures, such as an emergency disconnect or autoshear function of the BOP system on its own, there is no ability to manipulate the tool joint position or the level of tension or com pression in the drill pipe.
From page 151...
... This does not mean that the BOP must be capable of shearing every drill pipe at every point. It does mean that the BOP design should be such that for any drill string being used in a particular well, there will always be a shearable section of the drill pipe in front of some BSR in the BOP.
From page 152...
... Recommendation 3.9: BOP systems should be designed to be testable without concern for compromising the integrity of the system for future use. MOBILE OFFSHORE DRILLING UNITS Findings Summary Finding 4.1: Once well control was lost, the large quantities of gaseous hydrocarbons released onto the Deepwater Horizon, exacerbated by low wind velocity and questionable venting selection, made ignition all but inevitable.
From page 153...
... Finding 4.2c: The standby generator did not automatically start and could not be started in manual mode, indicating deficient reliability in the backup system needed to restore main generator power. Finding 4.2d: Poor performance by the standby diesel generator may indicate that insufficient environmental testing was specified for this critical, last-resort power system to demonstrate robust capability or any local indication of generator starting availability.
From page 154...
... Observation 4.2: The attempts to start the standby diesel generator and re store power for damage control were acts of bravery. Observation 4.3: Conditions of explosion, fire, loss of lighting, toxic gas, and eventual flooding and sinking could have resulted in many more inju ries or deaths if not for the execution of the rig's evacuation.
From page 155...
... military, to address the com plex and integrated "system of systems" challenges faced in safely operat ing deepwater drilling rigs. The method should take into consideration the coupled effects of well design and rig design.
From page 156...
... Recommendation 4.11: Drilling rig contractors should review designs to ensure adequate redundancy in alarms and indicators in key areas of the rig. Recommendation 4.12: Drilling rig contractors should require realistic and effective training in operations and emergency situations for key personnel before assignment to any rig.
From page 157...
... Recommendation 4.19: Operating companies and drilling contractors should institute a certification authority, accountable to the head of the company, to act as the senior corporate official responsible and account able for meeting the conditions set out in a safety management system. This appointment should provide a powerful voice for safe execution of operations and surety in dealing with emergencies: the official should have the authority and responsibility to stop work if necessary.
From page 158...
... Observation 5.2: Processes within the oil and gas industry to assess ade quately the integrated risks associated with drilling a deepwater well, such as Macondo, are currently lacking. Observation 5.3: As offshore drilling extends into deeper water, its com plexity increases.
From page 159...
... These en deavors should be conducted to benefit the efforts of industry and gov ernment to instill a culture of safety. Summary Recommendation 5.3: Industry should undertake efforts to ex pand significantly the formal education and training of industry personnel engaged in offshore drilling to support proper implementation of system safety.
From page 160...
... A comprehensive lessons-learned repository should be maintained for indus trywide use. This information can be used for training in accident preven tion and continually improving standards.7 Summary Recommendation 5.5: Industry should foster an effective safety culture through consistent training, adherence to principles of human fac tors, system safety, and continued measurement through leading indica tors.
From page 161...
... Summary Observation 6.3: Overall, the regulatory community has not made effective use of real-time data analysis, information on precursor in cidents or near misses, or lessons learned in the Gulf of Mexico and worldwide to adjust practices and standards appropriately. Recommendations Summary Recommendation 6.1: The United States should fully implement a hybrid regulatory system that incorporates a limited number of prescrip tive elements into a proactive, goal-oriented risk management system for health, safety, and the environment.
From page 162...
... Recommendation 6.5: Quantitative risk analysis should be an essential part of goal-oriented risk management systems. Summary Recommendation 6.6: BSEE and other regulators should iden tify and enforce safety-critical points during well construction and aban donment that warrant explicit regulatory review and approval before op erations can proceed.
From page 163...
... This information can be used for training in accident prevention and continually improving standards.8 Summary Recommendation 6.15: A single U.S. government agency should be designated with responsibility for ensuring an integrated approach for system safety for all offshore drilling activities.
From page 164...
... Summary Recommendation 6.23: BSEE and other regulators should un dertake efforts to expand significantly the formal education and training of regulatory personnel engaged in offshore drilling roles to support proper implementation of system safety. Recommendation 6.24: BSEE should exert every effort to recruit, develop, and retain experienced and capable technical experts with critical domain competencies.
From page 165...
... 2011. Report of Investigation into the Circumstances Surrounding the Explosion, Fire, Sinking and Loss of Eleven Crew Members aboard the Mobile Offshore Drilling Unit Deepwater Horizon in the Gulf of Mexico April 20–22, 2010, Vol.


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