Drilling and workover rigs on Floating Production Systems (FPSs) are fastened to the decks of offshore structures sea fastenings to prevent movement during hurricanes. Sea fastenings include bolts, weldments, braces, or other means. During Hurricane Ivan, a number of drilling or workover rigs shifted. These movements are being assessed along with the current design philosophy and criteria for storm sea fastenings, rig and storm sea fastening installation practices, and onboard storm operational practices to ready FPSs for a hurricane. Results will provide information that can be used to assess any needs to revise tie-down criteria or practices to avoid future damage.
Phase 1 is being sponsored by MMS. The objectives are to collect information on FPSs that had drilling rig movements during Ivan and complete preliminary analyses to understand the observed movements relative to existing codes and practices. A Phase 2 study is envisioned as a JIP that would complete additional and more detailed analyses of rig tie-down failures and successes, and evaluate tie-down options for preventing observed movements.
The data collection phase has been completed and is documented in this report.