EuroWire March 2018

Technical Article

The use of steel strip, shaped wire and round wire in the production of umbilical cable and submarine cable By Sean Harrington, Ceeco Bartell Products, Canada

This article introduces subsea umbilical cables and subsea power cables, with discussion of technology drivers, engineering challenges and design advances. Umbilical cables and submarine cables offer a full range of solutions which, thanks to innovative designs, materials and state-of-the-art processes, meet all of the demanding requirements of such applications. During the last few years, offshore oil extraction activity has been constantly increasing. New platforms are being continuously installed in different parts of the world, and operate in deeper and deeper waters. The safe and efficient interconnection from the topside platforms and vessels to the well heads and pumps on the sea floor is necessary to transfer power and data, as well as hydraulic and other fluids to guarantee reliable oil extraction operations. The local generation of electric power and the subsequent distribution to various appliances achieves lower generation costs. In addition, broadband communication systems are now an essential feature of the most modern communication and process control systems. Subsea umbilical cables form this vital link among the various centres of operation. They must be able to withstand high mechanical and chemical stresses, high operating temperatures and pressures in order to ensure the continuous and reliable supply of services in the harsh environments below the sea.

▲ ▲ Figure 1 : Umbilical cables and submarine cables offer a full range of solutions

A subsea production umbilical forms a critical link between the production system and host facility conveying hydraulic power, process chemicals and electrical power and signals to oil and gas production or water injection centres. An umbilical may be many kilometres in length and must be highly reliable in the subsea environment where recovery and repair may not be possible or may prove extremely costly. Shorter length umbilicals are also used to facilitate connection between subsea structures and to facilities’ offshore installation activities, and to control the pressure retaining systems during drilling of wells and well workover activities. Figure 3a shows a typical example of a subsea power cable capable of transmitting electric power between

Umbilical cables and submarine cables have to be designed to suit static and dynamic applications in water depths of up to 3,000m and are composed of any possible combination of hydraulic lines (thermoplastic hoses or steel alloy tubes), low-voltage electrical control cables, medium-voltage power transmission cores and optical signal components. An umbilical is basically a composite cable used by the offshore oil and gas industry for linking the various elements of subsea oil and gas production systems or in support of intervention or construction activities. The umbilical may contain steel tubes, thermoplastic hoses, electrical power and/or signal cores, and optical fibres, otherwise known collectively as functional components.

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March 2018