A problem Dong Energy was having last year with the replacement of a damaged subsea control module on the Danish sector Oselvar field was solved using 3D visualization technology at Aker Solutions’ Forus IPort performance technology in Norway, helping to reduce the time required to remove the SCM from 14 days to less than 24 hours.
The operator discovered the damage after connecting the high pressure riser. Investigations proved that a crash point made it impossible to get access to the control module without first removing the HP riser.
The Aker Solutions’ visualization team had delivered handbooks, posters and animations to Dong before, so a library with 3D models of all Oselvar’s subsea installations already existed. A 3D simulation of the tree, the crash point, the equipment and all its surroundings was made, and the tool for replacing the SCM was customised in 3D. Critical measurements and pictures were then sent to subsea personnel at Aker’s Ågotnes base, where the actual tool was customised, then returned to the IPort for final verification in 3D simulation.
A 3D sequence was then recorded and sent to the Maersk Giant rig in the field. The rig used the pictures and measurements to cut the frame surrounding the HP riser at the seabed, and pictures of the underwater operation were sent to the IPort for verification. ‘This was all done with no downtime on the rig,’ said Dong completion engineer Hasse Herland. ‘The operation to remove the SCM was prepared in the IPort while the rig was doing other planned operations. We used 23 hours of rig time, instead of the alternative solution which would have involved plugging the well and pulling out the HP riser system. Our estimated savings are a minimum 14 days of rig time; about NKr100 million.’
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