Chapter 1. Structural Integrity Management of Ageing Offshore Structures: A Regulatory Perspective

The North Sea offshore industry is now over 50 years old with the installation of the first platform in the North Sea in 1966. The majority of platforms have now exceeded their design lives and are considered to be ageing structures in the life-extension phase. Safe operation requires the implementation of structural integrity management systems that recognise the potential issues associated with damage, deterioration and obsolescence.

The UK Health and Safety Executive (HSE) Energy Division and Norway’s Petroleum Safety Authority(PSA)have been very active in the development and promotion of good practice in the integrity management of ageing offshore installations from the outset. In the UK, with the transfer of responsibilities from the UK Department of Energy to the HSE following the Piper Alpha disaster of 1988, the HSE has funded a substantial research programme on ageing and life extension (ALE) issues. This has supported the development of codes, standards and guidance on structural integrity management and ageing / life extension. The HSE has under taken major industry-wide inspection programmes and led significant stakeholder engagement activities to promote awareness of ALE within the offshore industry. A particularly successful initiative was the creation of the Energy Institute Ageing and Life Extension Work Group which supports the development of guidance on ALE issues and continues to be very active. Most recently, the HSE has extended its activity to the assessment of extreme weather loading, characterised by the 10,000-year event, which was not a design requirement for ageing installations and now presents a challenge to these.

Similarly, PSA in Norway has placed an increasing focus on ageing facilities since the late 1990s. By then, a few fixed offshore platforms had exceeded their original design life but, more significantly, a number of drilling rigs showed signs of ageing and had exceeded their design life. A joint letter to the industry about managing ageing drilling rigs was issued by the HSE in the UK and PSA in Norway in 2003. From 2005 to 2010, PSA undertook a key programme on ageing and life extension of oil and gas facilities. This key programme initiated several technology-development projects with the aim of increasing knowledge in the industry on life extension assessment.

This paper outlines the work of the offshore regulatory authorities on the issue of ageing and life extension and concludes that, with the focus on energy transition, ALE will present further challenges to the safe operation of offshore structures for the foreseeable future. The management of ALE in the evolving offshore environment also highlights the importance of suitable integrity management practices and the role of regulation in ensuring workforce safety.