Dynamic positioning system and hydraulic gangway reduces reliance on helicopters.
The transfer of personnel and technicians to offshore platforms has been the domain of one form of transport in the past and present: the helicopter. Limitations of this form of transport have been recognised for a long time – helicopters are not the most practical solution, but until now they have been the only one.
The use of sea transportation was felt too difficult and potentially dangerous in the past. But one company has now come up with a solution that it feels will revolutionise the transportation of crew, technicians and spare parts to platforms, rigs and floating vessels located offshore.
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Offshore Solutions BVÂ provide OAS (offshore access systems), a concept which has been developed over the last ten years.
“This technology was developed for the southern sector of the North Sea, where for quite a number of years it has been recognised that it would be ideal if we could transfer people by vessel to offshore installations,” says Graham Mapes, business development manger, Offshore Solutions and Fabricom. “The only other option is to use helicopters, which are limited.”
“Companies have come to us and said that with helicopters they get an average of five hours productive time out of a man per day at a normally unmanned installation. With our solution you can get 11 hours, and technicians can bring more equipment and can do more preparation before leaving to carry out the maintenance work,” explains Mapes.
Previous attempts using a boat or ship to transport crew and parts would require the vessel to station in a landing area, and the employees would then jump off onto the platform. In rough conditions, this becomes potentially dangerous and is avoided by most companies.
“It was only until recently that technology came allowing us to be able to measure the motions of the vessel, and to relay this to a computer processor and into moving hydraulic fluid – what we call the heave-compensation system,” he continues.
“So now we can make the safe connections of the gangway, which requires a fixed pole on the offshore installation. We then connect the gangway to the pole and the system begins, creating a safe walkway for the staff.”
The current limit for the OAS’s heave-compensate system in rough seas is 2.5m significant wave height – a spectrum that covers up to a maximum of roughly 4.5m in wave height.
However, Mapes asserts that very few people will actually want to walk across at 2.5m significant wave height due to movement.
“We can design for 3m to 3.5m swell, and have actually designed one for a much larger vessel for 5m, but there are actually very few people who would want to walk across a moving gangway at this wave height,” says Mapes.
Despite being a relatively new company, as well as dealing with the conservative nature of the oil and gas industry, Offshore Solutions has started to see demand picking up for the gangway systems. Shell Qatar recently announced that it had signed a deal with the company for the provision of gangways.
“The contract with Shell will be for five years on a leasing basis. We have worked for Shell in the North Sea, for the ONEgas project, and the good work we have done for them there has led to further business for us,” explains Mapes.
“We had expected the phone to be constantly ringing when we started, but it wasn’t the case. It wasn’t until we had a year of superb operations under our belt and Shell’s commitment to our technology that interest has begun to pick up.”
Offshore Solutions’s gangways will be used for Shell Qatar’s Pearl GTL project. The company’s range of lighter OTS (offshore transfer system) gangways are currently in development, and will be deployed in the Middle East due to the more benign waters.
“The first OTS unit is going to go to BP in the Caspian, which is due for delivery in Baku at the end of February next year. Like the Caspian, the water conditions here are benign and you don’t really need the OAS. We hope to have saleable OTS products that we can bring to the market by midsummer next year,” says Mapes.
