 the population within the plant gates at any one time. Authorized access to process areas is needed for operators and maintenance crew. Non-operational personnel are located in occupied building which by location and design should not be at risk. Civil assets, police, ambulance and Fire Brigades are available to assist in a major crisis and carry out combined emergency exercises for that purpose.
Although Prelude will be the largest floating structure in the world, its dimensions at 488 by 75 by 105 m are minimal when compared to the many acres afforded to an onshore plant. The total population needed to run the show offshore remains constant. And at least initially Prelude will need to tackle the emergency on its own. If a major accident occurs, with serious injuries, burns etc, ambulances cannot arrive within 12 minutes or so at the gates of the Prelude plant. Given that search and rescue will commence from Broome, this town is 300 miles from Prelude. On a good day, outward and return journey time could be 5 hours with an additional ½ hour loading injured persons on board – plus refueling the aircraft prior to its return. If onward transition of seriously injured persons is necessary, on the assumption that Broome will have limited facilities, getting casualties to a hospital that can handle serious burns, and provide intensive care otherwise, involves another 2 and ½ hour flight to Perth.
How does the total number of persons offshore have such an influence on the quantification of risk?
This is simply because, as with all offshore installations, the total number of persons required to run the LNG plant, day and night, are present within the plant boundaries so the potential loss of life (PLL), should something go seriously wrong, takes that fact into account. There is no getting away from this; it’s just the way the arithmetic of risk works. PLL for Prelude will be quantified as the average risk to an individual on the facility multiplied by the total numbers on board.
Can due diligence by the Board of Royal Dutch Shell be assumed?
For such a large capital project I am sure the economic viability of Prelude was scrutinized closely.
With respect to health and safety risks my assumption is that the project team assured the Board that the risks of FLNG had been demonstrated to be as low as is reasonably practicable. Despite health and safety risks to the crew of Prelude being higher than an onshore LNG plant my assumption is that Directors are aware of this. Given that the potential consequences of explosion and fire offshore must be higher than onshore, the only way this can be refuted is if Shell can guarantee that the probability of loss of containment on Prelude is negligible. No one will do that.
Offshore Installations have a poor track record in preventing loss of containment
Gas and oil leaks in the highly regulated North Sea are recorded in government statistics. These are either minor leaks or significant leaks. With reference to gas leaks, a significant leak is one where a flammable atmosphere exists as a result of the leak which could explode if it came into contact with a source of ignition. In a recent years significant gas leaks were occurring somewhere in the oilfield every 5 days, i.e. 83 leaks that year in total. Shell has had more than its fair share of leaks; on Brent Charlie for example it had 6 such leaks in one day. Shell reacted and tried to keep ahead off this problem on all its installations by fitting temporary clamps to hydrocarbon carrying pipes. From its own data, not disputed, hundreds of these repairs were not approved by a competent person prior to installation. A public inquiry in 2006 attributed the cause of deaths on Brent Bravo to a materially defective temporary repair. So Shell has previous form. Hopefully this North Sea behavior by Shell is non-transferable down under. The data on North Sea gas leaks covered circa 200 installations and many other Operators, but still it makes the striking, and irrefutable point that offshore installations by their very nature, have challenging tech