Offshore decommissioning

Before decommissioning may begin, an oil and gas company must submit the relevant risk management plans to the main regulator – the National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) – for assessment and acceptance.

The plans required for decommissioning can include a safety case, well operations management plan and environment plan. NOPSEMA’s dedicated assessment teams, which comprise of highly qualified and experienced experts, assess each plan against strict criteria – including an occupational health and safety case, an environment plan and for management of well integrity.

A range of technical decommissioning and disposal options exists for offshore facilities, each of which must be evaluated on a case-by-case basis. The scope of consideration should include a broad range of aspects and not only focus on the vicinity of the structure.

Decommissioning options:

  • complete removal, disposal onshore or offshore
  • partial removal, disposal onshore or offshore
  • abandonment in-situ
  • alternate use, either within the oil and gas industry or other industries / purposes.

The method of removing and disposing of a structure depends on factors such as the type of construction, size, distance to shore, weather conditions, the complexity of the removal operation and the environmental impact. It must also consider the safety of workers.