Rethinking Rig Embarkation

The market for a safer ship embarkation system is growing as drilling rigs move farther offshore.

• By Jerry Laws
• Mar 01, 2008

Work on an offshore oil or gas rig presents many hazards. Getting out there can be dangerous, too, because of sea and weather conditions. Helicopter transport has a good safety record, but even the United Kingdom Offshore Oil and Gas Industry Association Ltd, which claims to be the world leader in offshore helicopter safety, has experienced two fatal crashes, with 18 deaths, in the past decade. Worldwide in 1995-2005 (the latest period for which worldwide comparisons are possible), there were 63 fatal accidents around the world during offshore helicopter transport, which annually moves millions of passengers back and forth. More than 56 million were flown from 1997 to end of 2006 in the UK Continental Shelf region alone. These statistics come from the association’s “UK Offshore Public Transport Helicopter Safety Record 1977-2006,” which calculated this region had an occupant fatal accident rate of 1.39 per 100,000 flying hours when considering the helicopter types now in use and a non-fatal reportable accident rate of 1.55 per 100,000 flying hours.

Helicopter transfer is expensive, their airspace is becoming crowded, and deepwater rigs are working farther and farther from shore in some parts of the world, said Larry Denton, who works on crew transfer as the business development manager, Ship Systems for Lockheed Martin’s Maritime Security and Ship Systems line of business, which is based in Baltimore.

The alternative to helicopters is moving workers by ship, which presents hazards of its own when workers are lifted and lowered by crane in baskets between a rig and a ship’s deck. Lifting and hoisting operations of all types—not just crew transfers—are one of the leading causes of deaths and serious incidents in global exploration and production activities, according to the International Association of Oil & Gas Producers (OGP), whose Safety Committee’s Task Force on Lifting and Hoisting developed a Recommended Practice document to focus the industry on safe lifting. (The document lists three essential principles for lifting personnel: Avoid it “unless the risk has been demonstrated as being as low as is reasonably practicable,” lift according to a specific personnel lift plan for that lift, and properly secure lifted personnel with lanyards “unless written procedures and risk assessment require otherwise.”)

High Lifts and High Seas
The vertical lifts range from 40 feet to more than 100, said Denton. “Generally, you’re talking about transferring people in significant sea states, so you’ve got a vessel that’s moving around quite a bit in the water,” he said. “There’s limited safety for the person as they’re in the basket and being lifted to the rig.

“You start to get a pendulum effect, where if the crane isn’t directly above the basket, the basket starts to move quite significantly as it’s raised to the crane. Some of the most significant injuries occur during that lifting process, where people either fall into the water or, due to the pendulum effect, they hit the rig. On the other hand, you have people hurting their backs and necks when you’re setting that down on the rig, because obviously, in significant weather, it’s not always a nice landing.

“The ship’s performance capabilities are a huge component of the safety because the ship’s ability to remain in close proximity to the rig during the transfer and to limit the motions of the ship during the transfer are huge,” he said.

A new ship design and a new type of transfer interface are Lockheed Martin’s contributions to a comprehensive transfer system launched recently with VIKING Life-Saving Equipment Norge AS. VIKING’s portion is Selstair, a collapsible staircase with non-slip aluminum steps and landings, handrails, and a safety net around the staircase. This embarkation system will work in any weather and offers significant cost advantages over helicopter transport, the companies say.

The patented SLICE® vessel design has four submerged pods. This decreases the vessel’s surface area, lessening the impact of water movement on it and giving SLICE “phenomenal seakeeping ability” while under way and while stationary to transfer, Denton said. As for the third component, Lily Birmingham, a Lockheed Martin engineer on the project, described the CEway crew transfer system as a unique interface riding on rails. It allows rotational freedom and will slide on the boat to accommodate some of the travel motion, she said.

The market for this solution is growing as drilling moves farther offshore in West Africa, Southeast Asia, and the North Sea. “There are many areas of the world where you’re talking significant sea states, high winds, and pretty good distances from shore that would feed right into this type of transfer system,” said Denton.

This article originally appeared in the March 2008 issue of Occupational Health & Safety.