DC/FO, A Lean and Powerful DC Subsea Control Infrastructure

Abstract

Subsea controls architectures have been traditionally based on large size project-specific umbilicals integrating hydraulics, data, power and chemicals. Tieback length and power consumption drive the dimensioning of umbilical cross-section. The submarine telecom industry has an extensive track record of highly reliable, long reach, standardized solutions for DC powering and data transport. An alternative cost effective subsea control infrastructure solution has been developed leveraging on the submarine telecom industry experience, based on reliable super-structural and standardized DC subsea power and optical fiber communication cable network, compatible with existing brown fields and future green fields subsea control systems, so-called DC/FO solution. This innovative solution offers a number of advantages inspired from the telecom industry: Standardization – the same standard cross section can be used regardless of tie back length or power consumption demand; Reparability and Extendibility – The cable and its end terminations can be lifted to surface for repairs or extensions at sea with standardized jointing technology, simplifying the tie-back of new prospects and enabling phased development; Open platform – electrical power and communication interfaces can be connected to any SPS supplier equipment; Virtually unlimited reach within Oil and Gas fields – the system is dimensioned to serve the longest tie backs currently contemplated by the industry; Large power supply capability. This solution is an enabler for new applications such as AUV recharge or E-Field sensing. On longer term, all-Electric trees can be powered through DC/FO solution, allowing further downsizing and cost reduction of legacy umbilical cross-section with the removal of hydraulic tubes.