Safety System Design
Recommendation 4.2: Rigs should be designed so that their instrumentation, expert system decision aids, and safety systems are robust and highly reliable under all foreseeable normal and extreme operating conditions. The design should account for hazards that may result from drilling operations and attachment to an uncontrolled well. The aggregate effects of cascading casualties and failures should be considered to avoid the coupling of failure modes to the maximum reasonable extent.
Recommendation 4.3: Industry and regulators should develop fail-safe design requirements for the combined systems of rig, riser, BOP, drilling equipment, and well to ensure that (a) blowouts are prevented and (b) if a blowout should occur the hydrocarbon flow will be quickly isolated and the rig can disconnect and reposition. The criteria for these requirements should be maximum reasonable assurance of (a) and (b) and successful crew evacuation under both scenarios.
Recommendation 4.4: Industry and regulators should implement a method of design review for systemic risks for future well design that uses a framework with attributes similar to those of the Department of Defense Standard Practice for System Safety (DoD 2000), which articulates standard practices for system safety for the U.S. military, to address the complex and integrated “system of systems” challenges faced in safely operating deepwater drilling rigs. The method should take into consideration the coupled effects of well design and rig design. (See Chapter 5 for a discussion of safety system qualities.)
Recommendation 4.5: Industry should institute design improvements in systems, technology, training, and qualification to ensure that crew members are best prepared to cope with serious casualties.
Recommendation 4.6: ABS should eliminate any ambiguity in its rules requiring that propulsion control systems for MODUs shall “in general” comply with the Steel Vessel Rules. All of the primary control and monitoring systems and critical backup systems on these MODUs should be designed and tested to the highest standards in the industry.
Automatic Redirection of Hydrocarbon Flow Overboard
Recommendation 4.7: Industry should develop and implement passive or automatic methods to redirect hydrocarbon flow overboard. Ide-