U.S. CHEMICAL SAFETY AND HAZARD INVESTIGATION BOARD INVESTIGATION REPORT VOLUME 2 EXPLOSION AND FIRE AT THE MACONDO WELL (11 Fatalities, 17 Injured, and Serious Environmental Damage) DEEPWATER HORIZON RIG MISSISSIPPI CANYON BLOCK #252, GULF OF MEXICO KEY ISSUES IN VOLUME 2 APRIL 20, 2010 • BOP TECHNICAL FAILURE ANALYSIS • BARRIER MANAGEMENT AT MACONDO • SAFETY CRITICAL ELEMENTS REPORT NO. 2010-10-I-OS 6/5/2014 Macondo Investigation Report Volume 2 June 5, 2014 [This page left intentionally blank.] 2 Macondo Investigation Report Volume 2 June 5, 2014 Volume 2 Technical findings on the Deepwater Horizon blowout preventer (BOP) with an emphasis on the effective management of safety critical elements 3 Macondo Investigation Report Volume 2 June 5, 2014 [This page left intentionally blank.] 4 Macondo Investigation Report Volume 2 June 5, 2014 Contents VOLUME 2 .................................................................................................................................................. 3 ACRONYMS AND ABBREVIATIONS ................................................................................................... 10 1.1 Volume 2 Synopsis ........................................................................................................................ 13 1.2 Key Findings .................................................................................................................................. 14 2.0 CONTROLLING FORMATION PRESSURES WITH THE DEEPWATER HORIZON BLOWOUT PREVENTER ........................................................................................................... 17 2.1 BOP Sealing Elements ................................................................................................................... 19 2.2 The BOP as a Physical Barrier ....................................................................................................... 21 2.3 Functioning the Deepwater Horizon BOP ..................................................................................... 23 2.3.1 BOP Control System ......................................................................................................... 23 2.3.1.1 Functioning Solenoid Operated Valves ......................................................... 25 2.3.2 BOP: Closing the Blind Shear Ram .................................................................................. 27 2.3.3 Initiating the AMF/Deadman Sequence ............................................................................ 27 2.4 Condition of the Well on April 20, 2010—Data Used to Recreate the Incident Events ................ 28 2.5 The Macondo Well Kicks—Incident Analysis of Well Control Response .................................... 28 3.0 THE BLOWOUT PREVENTER – FAILURE OF A BARRIER .................................................. 31 3.1 Correlating Physical Evidence from Macondo with the Events of April 20, 2010 ........................ 32 3.2 Failure Analysis of the Deepwater Horizon BOP .......................................................................... 34 3.2.1.1 Blue Pod: Disconnected Wires and the Drained Battery ............................... 36 3.2.1.2 Yellow Pod: Miswired High-Pressure Shear Closes Solenoid ...................... 37 3.2.1.3 Successful AMF/Deadman Tests on the Yellow Pod .................................... 38 3.2.1.4 Independent CSB Exemplar Solenoid Testing .............................................. 38 3.2.2 The AMF/deadman Successfully Fires on April 20, 2010 ................................................ 39 3.2.3 The AMF/deadman Fails to Seal the Well: Buckled Drillpipe ......................................... 43 3.3 Conclusion ..................................................................................................................................... 45 4.0 ESTABLISHING AND MAINTAINING EFFECTIVE BARRIERS .......................................... 47 4.1 Defining the Role of a Barrier: Major Accident Events ................................................................ 47 4.2 Barriers to Prevent or Mitigate MAEs ........................................................................................... 49 4.2.1 Visualizing Barriers using a Bowtie Diagram .................................................................. 52 4.2.2 Determining the Type and Number of Barriers to Reduce Risk ....................................... 55 5 Macondo Investigation Report Volume 2 June 5, 2014 4.2.3 Maintaining Effective Barriers ......................................................................................... 57 4.2.3.1 Barriers as Safety Critical Elements (SCEs) ................................................. 58 4.3 Conclusion ..................................................................................................................................... 61 5.0 DEEPWATER HORIZON BOP NOT TREATED AS A SAFETY CRITICAL ELEMENT ...... 62 5.1 Identification of a SCE................................................................................................................... 64 5.1.1 BOP Component Failure Identified in DWH Hazard Analysis ........................................ 64 5.1.2 DWH Hazard Analysis Did Not Address BOP Design Capabilities ................................ 65 5.2 Defining Performance Requirements of a SCE ............................................................................. 66 5.2.1 Drillpipe Exceeded Shearing Capabilities of DWH Blowout Preventer .......................... 66 5.2.2 Prescribing Minimum Reliability Requirements of a BOP .............................................. 68 5.3 Performance Assurance of an SCE ................................................................................................ 70 5.3.1 No Assurance Activities for the Critical AMF/Deadman Solenoid Valve ....................... 71 5.3.2 Current Deadman System Function Tests Are Inadequate ............................................... 72 5.3.3 Assurance Activities of Human Actions ........................................................................... 76 5.4 Gap Closure ................................................................................................................................... 77 5.5 Verification Activities—The Independent Competent Person ...................................................... 78 5.6 Conclusion ..................................................................................................................................... 79 6.0 ANALYSIS OF RECOMMENDED PRACTICES AND REGULATIONS REGARDING THE BOP AND OTHER SAFETY CRITICAL DEVICES .................................................................. 81 6.1 Lifecycle of SCEs under BSEE ..................................................................................................... 82 6.1.1 Hazard Analysis not Focused on Targeted Risk Reduction of Major Accident Events ... 82 6.1.1.1 Lack of Targeted Risk Reduction Requirements: Parallel Findings between the CSB Investigations ...................................................................................................... 84 6.1.2 Lack of Defined Performance Standards for all SCEs ...................................................... 85 6.1.3 Performance Assurance and Verification Needed for all SCEs ........................................ 86 6.1.4 Gap Closure Important for Continuous Improvement of SCE Effectiveness ................... 87 6.2 Regulatory Responses Post-Macondo: Prescriptive Change versus Continuous Improvement .... 88 6.2.1 BOP Shearing Capability—An Illustrative Example of Diverse Regulatory Responses . 89 6.2.2 Proposed Regulatory Changes Suggest US Recognition of the Importance of Lifecycle Management of Safety Critical Equipment ......................................................................................... 92 7.0 VOLUME 2 CONCLUSIONS: TECHNICAL SAFETY FAILURES REVEAL BROADER REGULATORY GAPS ................................................................................................................. 93 6 Macondo Investigation Report Volume 2 June 5, 2014 8.0 RECOMMENDATIONS ............................................................................................................... 95 APPENDIX 2-A: DEEPWATER HORIZON BLOWOUT PREVENTER FAILURE ANALYSIS ......... 98 APPENDIX 2-B: DEEPWATER HORIZON RBS 8D BOP MUX CONTROL SYSTEM REPORT ...... 99 APPENDIX 2-C: SCENARIOS WHEN TWO BSRS WOULD NOT BE OPTIMAL ............................ 100 REFERENCES ......................................................................................................................................... 101 7 Macondo Investigation Report Volume 2 June 5, 2014 Figures and Tables Figures Figure 2-1. The DWH BOP stack ............................................................................................................... 18 Figure 2-2. An annular preventer can seal the annular space around a drillpipe or an open hole. Pistons press up on the rubber component which pushes it inward to seal around the pipe or open hole. ......................................................................................................................................... 19 Figure 2-3. A pipe ram can seal the annular space around a drillpipe, but not an open hole without drillpipe present. ...................................................................................................................... 20 Figure 2-4.Control panel (left) and partial closeup of control panel on the Deepwater Horizon found in the driller’s