Looking at statistics for subsea producing wells in North America, Brazil and Norway the numbers indicate that approximately 50% of these wells were installed before 2005. Most of them rely completely on copper based communication i.e. no fiber optics installed, or at least not used. No Standard communication standard do not exist for neither topside nor subsea in systems installed before 2005 and communication throughput tends to be in the lower range of kilobit pr. second.
A large portion of existing wells are experiencing operational problems related to performance degradation in infrastructure and equipment, and are not capable of delivering communication interfaces for upgraded instrumentation and control requirements like multiphase meters, permanent reservoir monitoring and Subsea PowerGrids.
This paper looks into solutions for increasing communication throughput while simultaneously mitigating problems due to degeneration of copper cable umbilcals in a cost efficient way. Increased throughput is utilized as expanded connectivity, delivering new standardized communication interfaces both subsea and topside, and at the same time being backwards compatible for already installed subsea equipment.
The combination of being backwards compatible with the use of standardized communication interfaces gives extended lifetime for valuable communication infrastructure; umbilicals. Large benefits of the proposed solution are also achieved during upgrading of subsea installed equipment since not all subsea installed units must be upgraded at the same time as the topside-subsea communication link are upgraded.
To be able to supply enough electrical power to new subsea units on an existing umbilical already almost fully utilized a transformer based solution are described.
For umbilicals with very low IR (Insulation Resistance) values, a transformer setup for lifetime extension of the umbilical are also described.