Subsea job sets world record
The picture is an illustration of the hot tap system ready for drilling above a valve on the sea bed.
“Being able to connect a spur to a producing pipeline yields significant cost savings,” says Bjørn Kåre Viken, vice president for marine technology and operations in StatoilHydro.
Enhanced flexibility in deep water is another advantage of such operations, two of which were conducted on Ormen Lange in a depth of 860 metres. The operations were done to tie in a new subsea template in the southern part of the Ormen Lange field to the existing infrastructure on the sea bed.
“Remotely operated hot tapping utilises much of the same technology as the manual procedure using divers,” Mr Viken explains.
“However, the technology has been further developed and tailored to the pressure and other conditions encountered at these depths.”
The two hot taps were monitored and controlled from the surface, assisted by 100 sensors, 23 cameras and 18 subsea computers deployed on the seabed to transmit data via heavy duty cables.
“We’re a world leader in this technology, which will also be important for future projects,” Viken explains. “Substantial cost savings can be achieved when developing mature areas.
“That’s because the method allows existing pipelines to be used, so marginal fields can be tied back to older infrastructure with good capacity.
“Using remotely operated hot tapping makes it possible to pursue operations in deep waters where divers can't be used.”
Preparatory work for the operations paid great attention to risk analysis and understanding. The technology has also been carefully tested.
“This is an example of the way we can develop new solutions by challenging existing technology,” says Viken, who is very pleased with the work done. It demonstrates StatoilHydro’s leading-edge expertise and ability to execute major projects.