Safety for a Helicopter Load/Unload Operation on an Offshore Platform: Optimization From Several Viewpoints and the Psychological Aspects of the Marshaller

Field and Logistics. The field is located offshore, approximately 200 km (108 nm) away from the nearest airport. Flight time is 1 hour and 5 minutes in still air by a twin-engine medium-sized helicopter with two blades that has a cruise speed of 100 knots. In the case of a four-blade twin-engine helicopter with a cruise speed of 125 knots, flight time is 52 minutes in still air. In the case of vessel transportation, it takes 1 day from the nearest port. The field has been developed with facilities consisting of a central complex with living quarters and surrounding unmanned platforms. All wells are tied-in platforms. Produced fluids are sent to the central complex through subsea flowlines. The central complex has both a helideck and large crane equipment, while the platforms have a helideck and simple human-powered hoist equipment only, without any crane equipment. Regular or ad hoc but prescheduled material transportation is performed by an offshore support vessel between the nearest port and the central complex, except urgent/emergency transportation. Once materials arrive at the complex, the method of transportation from the complex to the platform depends on the situation. If there are small materials that can be managed by human carrying or lifting with simple hoist equipment, then those materials are transported by supply boat. Heavier materials that cannot be lifted by human power are transported by helicopter. There are three types of platforms—one-leg, three-leg, and four-leg. The number of well slots and the size of the helideck increase with the number of legs on the platform.