Subsea pipeline electrical heating is a relatively new technology in the Oil & Gas industry that has been developing, quite intensively during the last 15 years. There are two main techniques considered for subsea pipeline electrical heating; the first one, already deployed and in use, is Direct Electrical Heating (DEH) and the second one, currently in the final stage of the technology readiness process, is Electrical Heat Tracing (EHT). Electrical heating of subsea pipelines is expected to be increasingly deployed as an elegant technical solution to optimize the flow assurance management during production pipeline's service life and as a cost saving solution bringing significant reduction of projects overall CAPEX and OPEX.
TOTAL has been operating world's unique EHT PiP (Pipe in Pipe) subsea system, installed as an industrial pilot as a part of the Islay (TOTAL UK) project. Following the success of Islay project, TOTAL has studied implementation of the EHT PIP technology for an on-going deep water brownfield development which consists in the production of new reservoirs as a subsea tie back to an existing FPSO.
The "base case" field architecture, a hybrid loop concept, had been selected at initial conceptual study stage. Nevertheless, due to high CAPEX of the "base case" option, TOTAL decided to investigate alternative solutions for the preservation of the subsea production line during shut-down, among which an EHT system appeared as potentially attractive. Therefore, a study was conducted in order to assess if the EHT system is installable, safe, reliable, operable, efficient and environmentally sound throughout its required minimum operating life of twenty (20) years.
