Direct electrical heating (DEH) is a flow assurance technology developed to safeguard the well stream through the flowline to the platform. Alternating current transmitted via the cables returns through the steel in the pipe, which heats up due to its own electrical resistance.
DEH is an eco-friendly, chemical-free system, which greatly reduces the need for separation on the platform. This allows substantial savings in space and weight topside. By use of electrical current, the pipeline is heated to stay above critical temperature in the event of production shut-down or low production rates. DEH allows continuous operation of the production system and can be turned on as required providing the benefit of reduced down-time.
Direct Electrical Heating has successfully been installed at the following fields in the Norwegian Sea: Åsgard, Huldra, Kristin, Urd, Tyrihans, Alve, Morvin, and Skarv. Delivery lengths currently range from 6 to 44 km per flowline.
The DEH system
The DEH system comprises DEH Riser Cable, Armoured Feeder Cable, DEH Piggyback Cable and Integrated Protection System (IPS), and associated mechanical accessories.