Vol. 34 No. 15 31 March 2011 What Caused the Blowout Preventer to Fail? Det Norske Veritas (DNV) recently released a lengthy Electronic control pods are used to communicate report detailing the company’s forensic examination with the control panel on the rig and then activate of the Deepwater Horizon blowout preventer solenoids that, in turn, operate “various hydraulic (BOP), the failed “last line of defense” against the circuits and mechanical components on the blowout that occurred on 20 April 2010 at BP plc’s BOP Stack.” Macondo/MC252 well (see OSIR, 29 April 2010 and subsequent issues). The forensic investigation of the On the evening of 20 April 2010, the upper annular BOP is only a small part of the Joint Investigation (UA) of the Macondo/MC252 well was closed as (JI) of the event by the US Bureau of Ocean part of a series of two negative pressure tests. About Energy Management, Regulation and Enforcement 30 minutes after completing the second test, well (BOEMRE) and the US Coast Guard (USCG). An fluids started spilling onto the rig floor. The first additional report from the JI regarding the BOP is explosion is believed to have occurred at 21:49; the expected to be released within the next month; a Emergency Disconnect Sequence (EDS) activated full investigative report, addressing other aspects of from the bridge was noted at 21:56. It appears that the blowout, including the loss of 11 rig workers, is sometime between test completion and the activation of anticipated to be released later this summer. the EDS, the upper VBRs were closed and locked an action consistent with well control procedures. DNV’s findings appear to at least partially vindicate well operator BP and Transocean Ltd., the company A section of drill pipe containing a tool joint (the that owned and maintained the BOP. According to high-strength threaded end of the drill pipe section) DNV’s analysis, which focuses solely on the operation was caught between the UA and the upper VBRs, and of the BOP, the failure of the BOP may be distilled DNV believes that “forces from the flow of the well” into one sentence: “The primary cause of failure was caused it to buckle, forcing it to one side of the well identified as the BSRs [blind shear rams] failing to bore just above the BSRs. Because the drill pipe was close completely and seal the well due to a portion of positioned off the center of the BSRs, the rams were drill pipe becoming trapped between the ram blocks.” unable to shear the pipe as intended, and thus jammed partially open. DNV found no apparent mechanical The BOP stack, which was built by Cameron failures of the BOP due to inadequate maintenance. International, consisted of several systems: a Lower Marine Riser Package (LMRP) containing Because the buckling of the drill pipe likely occurred two annular preventers and two control pods, plus at the time of loss of well control, it appears that the five sets of rams, including blind shear rams (BSRs), BOP failed because it did not function as intended, casing shear rams (CSRs), upper variable bore despite essentially functioning as designed. Shearing rams (VBRs), plus middle VBRs and lower VBRs. the drill pipe by engaging the CSRs on 29 April 2010 Rams are large steel jaws that are designed to either may also have increased flow from the well. close over an open hole or shear drill pipes to cut off the flow from a well. The annular preventers This is not to say that the analysis found no other have a rubber sealing element that is capable of issues in well control operations related to the BOP. sealing the annulus between the drill pipe or drill DNV offers eight recommendations for industry, as collar; if no part of the drill stem is in the bore, the well as a long list of suggestions for further testing. annular blowout preventer closes on the open hole. Recommendations include: oil spill INTELLIGENCE REPORT 1. Further study of elastic buckling, and the effects 7. Study the effectiveness of intervention using of flow and constraints on “tubulars” present Remotely Operated Vehicles (ROVs), and their within BOPs; ability to be mobilized in an emergency; and 2. Study of shear blade surfaces to ensure their abil- 8. Institute industry performance requirements for ity to function as intended, regardless of the posi- back-up control systems equivalent to those for tion of the pipes within the well bore; primary control systems. 3. Study, review, and revision of well control prac- Additional public hearings focusing on the forensic tices to identify conditions under which common examination of the BOP will be held by the JI during procedures (e.g., closing annulars or VBRs) might the week of 4 April 2011 in Metairie, Louisiana (USA). adversely affect regaining well control; For more information, see www. 4. Review and revision of testing requirements to ensure deepwaterinvestigation.com/external/content/ that back-up controls are functioning as intended; document/3043/1047291/1/DNV%20Report%20 EP030842%20for%20BOEMRE%20Volume%20I. 5. Include redundancies in back-up controls to pre- pdf; www.deepwaterinvestigation.com/external/ clude common mode failure; content/document/3043/1047295/1/DNV%20 BOP%20report%20-%20Vol%202%20(2).pdf; 6. Study and implement industry requirements to www.dnv.com/press_area/press_releases/2011/ ensure the confirmation of the functionality of dnvreportondeepwaterhorizonbopconcluded.asp; and components like rams, annulars, and valves in the www.boemre.gov/ooc/press/2011/press0322c.htm. case of an emergency; Crescent City Cleans Up A Unified Command operation to mitigate pollution debris and sunken ships to prevent further petroleum following the Japan earthquake-triggered tsunami is spillage and clean up the oil that has already been underway in the small community of Crescent City, released as quickly and safely as possible, so the city California (USA). According to eye witnesses, the can begin to rebuild the harbor. nearly 7-foot (over 2-meter) tsunami waves “crushed” boats in the harbor and destroyed docks. At least Responders include the US Coast Guard, the California 47 boats were damaged and another 15 sank as a Department of Fish and Game, the Crescent City result of the 11 March 2011 tsunami. Docks and Harbor District, two dive teams, several oil spill response moorings were also severely damaged. Damaged and organizations, and contractors. The effort is being sunken vessels spilled oil into the city’s inner basin funded by the federal Oil Spill Liability Trust Fund, harbor. The Unified Command’s goal is to remove which currently carries a ceiling of US $2.75 million. 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Page 2 For subscriptions call 1-800-638-8437 31 March 2011 oil spill INTELLIGENCE REPORT To date, 1,428 gallons (34 barrels) of petroleum Crescent City, a small fishing village that sits near products have been removed from the harbor, the border of California and Oregon (USA), is no and over 1,250 cubic yards (960 cubic meters) of stranger to tsunami damage. In 1964, a deadly debris have been hauled away from the inner boat tsunami killed 11 people and destroyed hundreds basin. A heavy-lift crane barge was brought in of homes and businesses. In 2006, another tsunami from San Francisco (California) to begin removing caused approximately $10 million in damages to the sunken and damaged boats and debris. More than same harbor. 1,300 feet (400 meters) of containment boom have been deployed. So far, there have been no reports For more information, see www.piersystem.com/ of oiled wildlife. Many of the harbor’s docks will go/doc/3919/1050387/Crescent-City-Tsunami- remain closed to the public throughout the cleanup Response-Update-16; www.piersystem.com/go/ and rebuilding process, although the harbor has been doc/3919/1049743/; www.piersystem.com/go/ reopened to vessel traffic. Fishing resumed in the doc/3919/1047531/; and http://articles.latimes. area within days, and crab boats have already brought com/2011/mar/11/local/la-me-crescent-city-california- in their first catches of the season. 20110311. Anglo-Suisse Joins Gulf Cleanup Efforts Anglo-Suisse Offshore Partners, LLC, a Houston, be the case, the responsible thing to do was Texas (USA)-based operator in the Gulf of Mexico, mobilize.” As responsible party, Anglo-Suisse has joined the Unified Command in cleaning up the would be liable for costs associated with the Louisiana (USA) coastline impacted by crude oil last cleanup.