or to familiarise the crew with a project. “It is a great opportunity to go through complex procedures and run some alter- natives based on various environmental conditions. We can run through the ‘what if’ scenarios.

“This is also important for an operational review to consider what could be improved. We can go through every step and see it as it would happen offshore. It is not just a drawing on a screen but you can see the pro- ject from different points of view - even from above - which is not possible in real life.

Courtesey Statoil

also found out that when trying to simulate a real situation that offshore operations are very slow! This meant that they had to accelerate the ballast pumps and even skip some parts of the operation. “We really had to think about what we could speed up and crucially, everything has to be predefined, we can’t start to change things in the middle of the simulation.” Additionally, it appeared that the control of the steering lines was not modelled accurately enough: the advanced control system that is available in reality was not brought into the model.

An important outcome of the simulator exer- cise was that all the operations were more or less linked to each other and influence each other, he points out. “When we ballast a barge down with the crane connected there are some interaction effects which people ballasting the barge cannot see. The vessel starts to pull on the barge because of the DP system. This is a real influence, not a theory - there is a horizontal force.” It was also very difficult to keep the distance between the barge and vessel constant be- cause of the current load variation. “Keeping the two at a very close distance was very difficult for hours and hours.”

Insight into complex operations Additionally, another important finding concerned the moment when the barge is submerged and when the base frame had to be lifted off. Clearly, the two detach at a certain time. “If we keep ballasting down and then lift the frame off, the barge comes

8 report

up again. But how can we define this moment? We found that rather uniquely to engineering, we had to do it step by step, ballasting half a metre at a time. We couldn’t just do the operation in two big steps and this requires a lot of interaction between the crane driver and the person handling the ballasting.”

The simulation exercise certainly proved worthwhile, says Mr Breedeveld and he sees this development as particularly inter- esting for non-standard, complex operations

“When we ask the offshore crew to do a lift, we ask them to do it once and it has to be right; the captain and superintendent are responsible for the people onboard and the asset. Offshore work is all about being pre- pared. If these simulation tools can assist them in building up confidence and getting the feel for the operation in advance or if we can give the superintendent better in- put, it has to be good for the industry.” It also helps people be prepared for the unex- pected and how they would react if things don’t go to plan, he adds.

This simulation exercise led to a good understanding of the problem, emphasises Mr Breedeveld. “Giving people more back up and tools to make them better prepared is important. Ultimately, offshore is all about safety and safety is all about people!”

Real-time simulations

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