INTERBUS, the open sensor/actuator bus developed in 1985 by Phoenix Contact, is being used to help North Sea oil rigs. Chosen by Dolphin Drilling for a leakage detection system which monitors parts of the Rig structure, in areas that are not readily accessible.

Aberdeen-based Dolphin Drilling, part of Fred Olsen Group, are offshore drilling contractors whose operations also include well services and floating production. The INTERBUS system has been installed on their Borgsten Dolphin and Borgny Dolphin, both Aker H3 designed semi-submersible drilling units carrying out exploration drilling, sub-sea completions and work-overs of existing production wells in the British sector of the North Sea.

Both units are self-propelled and capable of moving to and from any area of operations world-wide. At present, the Borgsten Dolphin is carrying out work for Texaco on Strathspey Manifolds and the Borgny Dolphin is working for Shell on the Curlew Field Development. The leakage detection system comprises detectors placed inside those parts of the steel structure, which are underwater. If there are any cracks in the steelwork, they will detect any ingress of seawater and automatically set off an alarm. The system comprises 22 detectors in various areas and INTERBUS is used to transmit signals from them to a central alarm point mounted in a control room manned 24 hours a day.

The leakage detection system comprises detectors placed inside those parts of the steel structure, which are underwater. If there are any cracks in the steelwork, they will detect any ingress of seawater and automatically set off an alarm. The system comprises 22 detectors in various areas and INTERBUS is used to transmit signals from them to a central alarm point mounted in a control room manned 24 hours a day.

Dolphin Drilling opted for INTERBUS after evaluating various options because it was an easy-to-run and up-to-date system which was flexible and could be readily added to. "It is easy to install and there are less cables to site run than a conventional system," said Dave Leslie of Technical Support at Dolphin Drilling. "It is also extremely fast in operation compared with conventional systems."

"In addition, it has the ability to self monitor the system continuously and, if any faults in the hardware occur, the location can be readily recognised. It can also transmit information over long distances at high speed."

"Furthermore, the system can be added to at later dates very easily and carry information other than the present leakage detection system."