The oil and gas industry is continuously breaking barriers as new offshore fields are being developed in greater depths, further offshore and in extreme environments. Furthermore, the current high market demand requires quicker developments and enhanced reservoir recovery. Technology from the subsea communications sector is qualified and readily adapted to provide high-capacity, high-reliability communications to offshore surface and subsea structures. Additionally, the direct current (DC) power handling capability of the subsea cable may be exploited to efficiently deliver power for control and instrumentation systems.
The architectures at stake can range between dry node(s) to dry node(s) and dry node(s) to wet node(s) architectures. A significant benefit of the dry-wet solution is the availability of DC power distribution to the wet nodes (circa 10 kW/node). When combined with all electric subsea systems, this offers the opportunity for cost-effective high-reliability control systems in any offshore area. This paper will introduce a number of dry-dry and dry-wet solutions. The key features will be described and their technological, developmental status and cost aspects will be discussed.
The established subsea solutions for the international telecommunication systems that provide the worldwide web are characterised by: high-capacity (100s of GB/s) optical fibre transmission, DC power transmission (10s of kW) and high-quality, highly redundant configurations for fault-free subsea use over 25 years. These solutions actually affect three best-in-class features: reliability, undersea connectivity and ultra-large bandwidth.(Fig. 1, Fig. 2 and Fig. 3 are available in full paper)
The oil and gas industry seems poised to seize benefits of new technologies to enhance its business processes, knowing the oil demand is expected to grow from 80 millions barrel per day in 2005 to 130 millions barrel per day in 2020. As for the production from deep water, the production of both oil and gas is expected double from 2005 to 2010, the deepwater contribution shifting from 10 percent of the total production today to about 25 percent in 2015.
Therefore deepwater expenditures match a substantial increase in activity. From a capital expense (CAPEX) standpoint, it is expected that deepwater spending will amount $20 billion per year in 2010, with an accumulated $94 billion in 2006–2010 (Robertson 2005; Hillegeist 2003).
From a communication standpoint, the deepwater environment can be best characterized by extended reach, well over 100 km between any two points, sometimes in excess of 500 km away from shore. The environment may be severe, for example hurricanes like in the Gulf of Mexico or seasonal ice in the artic margin. Consequently, there is a trend to implement more and more subsea processing. Therefore, more and more control will be located subsea around the wellheads.
For the offshore network interlinking strategically located hub platforms, the capacity requirement is over 2.5 GB/s of aggregated traffic per node.