Electrical system management in preparation and during decommissioning. offshore installations

According to industry body Oil and Gas UK, [1] there are some 475 installations, 10,000 kilometres of pipelines, 15 onshore terminals and 5,000 wells that will eventually be decommissioned in the UK Oil and Gas industry. This paper summarises the various aspects when a platform is being prepared for decommissioning. These sometimes may become contradicting to each other. For example, on a maintenance front, power generation / electrical system availability and reliability figures need improvement to support wells plug and abandonment, while most downstream electrical distribution components can get those figures lowered. Moving away from hydrocarbon production creates an opportunity to revisit the classification of hazardous areas. Special attention is required for management of electrical safety competences, due to gap creation with experienced personnel moving on. This is paramount when methods of isolations are developed for redundant equipment. This paper is intended to aid both design and maintenance electrical engineers in supporting assets that are being prepared for decommissioning.