APPENDIX A Accidental Oil Spills and Gas Releases; Information, Models, and Estimates; and Supporting Figures, Tables, and Maps Posted at: https://www.boem.gov/Liberty/ This page intentionally left blank. Appendix A Liberty Development and Production Plan Final EIS Table of Contents Contents A-1 Accidental Large Oil Spills ...................................................................................... 1 A-1.1 Large Spill Size, Source, and Oil-Type Assumptions ............................................................ 1 A-1.1.1 OCS Large Oil Spill Sizes .......................................................................................... 1 A-1.1.2 Onshore Large Oil Pipeline Spill Size ........................................................................ 1 A-1.1.3 Source and Type of Large Oil Spills .......................................................................... 2 A-1.1.4 Historical Loss of Well-Control Incidents on the OCS and North Sea ....................... 2 A-1.2 Behavior and Fate of Crude Oils ............................................................................................ 3 A-1.2.1 Generalized Processes Affecting the Fate and Behavior of Oil................................. 3 A-1.2.2 Assumptions about Oil Spill Weathering .................................................................... 4 A-1.2.3 Modeling Simulations of Oil Weathering .................................................................... 4 A-1.3 Estimates of Where a Large Offshore Oil Spill May Go ......................................................... 5 A-1.3.1 Inputs to the Oil Spill Trajectory Model ...................................................................... 5 A-1.3.2 Oil Spill Trajectory Model Assumptions ..................................................................... 7 A-1.3.3 Oil Spill Trajectory Simulation .................................................................................... 8 A-1.3.4 Results of the Oil Spill Trajectory Model .................................................................... 9 A-1.4 Oil Spill Risk Analysis ............................................................................................................. 9 A-1.4.1 Chance of One or More Large Spills Occurring ....................................................... 10 A-1.4.2 Chance of a Large Spill Contacting: Conditional Probabilities ................................ 12 A-1.4.3 Results of the Oil Spill Risk Analysis: Combined Probabilities ................................ 12 A-1.5 Accidental Small Oil Spills .................................................................................................... 13 A-1.5.1 Small Spill Assumptions Summary .......................................................................... 13 A-2 Supporting Tables ................................................................................................. 15 A-3 Supporting Maps ................................................................................................... 36 A-4 OSRA Conditional and Combined Probability Tables ......................................... 52 A-5 Very Large Oil Spill Scenario ................................................................................ 59 A-5.1 Background .......................................................................................................................... 59 A-5.2 OCS Well Control Incidents ................................................................................................. 59 A-5.3 Hypothetical VLOS Scenario ................................................................................................ 60 A-5.3.1 Hypothetical VLOS Scenario for Open-Water or Summer ...................................... 61 A-5.3.2 Hypothetical VLOS Scenario for Winter ................................................................... 62 A-5.3.3 Hypothetical VLOS Scenario for Break-Up and Freeze-up ..................................... 62 A-5.4 Fate and Behavior of an Oil Spill ......................................................................................... 63 A-5.4.1 Spreading ................................................................................................................. 64 A-5.4.2 Evaporation .............................................................................................................. 64 A-5.4.3 Emulsification ........................................................................................................... 65 A-5.4.4 Natural Dispersion ................................................................................................... 66 Table of Contents i Appendix A Liberty Development and Production Plan Final EIS A-5.4.5 Dissolution ............................................................................................................... 66 A-5.4.6 Photooxidation ......................................................................................................... 66 A-5.4.7 Biodegradation ......................................................................................................... 67 A-5.4.8 Sedimentation .......................................................................................................... 67 A-5.5 Hypothetical VLOS Conditional Probabilities and Trajectory Modeling ............................... 67 A-5.6 Gas Release......................................................................................................................... 68 A-6 Recovery and Cleanup .......................................................................................... 68 A-6.1 Scenario Phases and Impact Producing Factors ................................................................. 70 A-6.1.1 Well Control Incident, Offshore Spill and Onshore Contact (Phase 1) .................... 70 A-6.1.2 Spill Response and Cleanup (Phase 2) ................................................................... 71 A-6.1.3 Post-Spill, Long-Term Recovery (Phase 3) ............................................................. 71 A-6.2 Opportunities for Prevention, Intervention, and Response .................................................. 72 A-6.2.1 Well Intervention ...................................................................................................... 73 A-6.2.2 Well Ignition ............................................................................................................. 73 A-6.2.3 Well Capping ............................................................................................................ 74 A-6.2.4 Relief Well ................................................................................................................ 74 A-6.2.5 Solid Ice Condition ................................................................................................... 75 A-7 Effects of a Very Large Oil Spill (VLOS) ............................................................... 76 A-7.1 Effects of a VLOS on Water Quality ..................................................................................... 76 A-7.1.1 Phase 1 (Well Control Incident, Offshore Spill, and Onshore Contact) ................... 77 A-7.1.2 Phase 2 (Spill Response and Cleanup) ................................................................... 78 A-7.1.3 Conclusion ............................................................................................................... 80 A-7.2 Effects of a VLOS on Air Quality .......................................................................................... 80 A-7.2.1 Phase 1 (Well Control Incident, Offshore Spill, and Onshore Contact) ................... 80 A-7.2.2 Phase 2 (Spill Response and Cleanup) ................................................................... 82 A-7.2.3 Phase 3 (Post Spill and Long-Term Recovery) ....................................................... 84 A-7.2.4 Oil Spill Trajectory Analysis ..................................................................................... 84 A-7.2.5 Conclusion ............................................................................................................... 84 A-7.3 Effects of a VLOS on Lower Trophic Level Organisms ....................................................... 84 A-7.3.1 Phase 1 (Well Control Incident, Offshore Spill, and Onshore Contact) ................... 85 A-7.3.2 Phase 2 (Spill Response and Cleanup) ................................................................... 87 A-7.3.3 Phase 3 (Post-Spill and Long-Term Recovery) ....................................................... 88 A-7.3.4 Conclusion ............................................................................................................... 88 A-7.4 Effects of a VLOS on Fish .................................................................................................... 89 A-7.4.1 Phase 1 (Well Control Incident, Offshore Spill. and Onshore Contact) ................... 89 A-7.4.2 Phase 2 (Spill Response and Cleanup) ................................................................... 92 A-7.4.3 Phase 3 (Post-Spill and Long-Term Recovery) ....................................................... 94 A-7.4.4 Conclusion ............................................................................................................... 94 A-7.5 Effects of a VLOS on Birds .................................................................................................. 95 A-7.5.1 Phase 1 (Well Control Incident, Offshore Spill, and Onshore Contact) ..................