Deepwater BowTie Ensures Safety Offshore

Since 2007, RPS’ HSE and Risk Management team in Perth, Australia have been working closely with the one of the world’s largest offshore drilling contractors: Ensco Plc, to develop Safety Cases for the ENSCO 7500 and ENSCO 8500-series of mobile offshore drilling units.

The ENSCO 7500 is an ultra-deepwater, dynamically positioned semisubmersible, capable of drilling in water depths up to 7,500’, and has worked for Chevron in Australia and in the US Gulf of Mexico.

The 8500-series are larger, newer units based on the ENSCO 7500 design, and were constructed at the Keppel FELS shipyard in Jurong, Singapore. The seventh, and last of the series (ENSCO 8506) was launched this year, each capable of operating at water depths of up to 8,500’.

The development of Safety Cases allows ENSCO to demonstrate that all risks associated with the operation of these rigs have been reduced to As Low as Reasonably Practicable.

Safety Case development is conducted using a qualitative risk assessment approach (in this case BowTie) which includes and requires extensive participation of the rig crew to meet local regulatory requirements.

Other parts of Safety Cases developed by RPS includes technical risk studies, such as Fire and Explosion Analysis (FEA), Evacuation, Escape and Rescue Analysis (EERA), Emergency Systems Survivability Analysis (ESSA), the description of the Company’s Safety Management System (SMS) and the facility description (FD).