Ageing and Life Extension of Offshore Oil and Gas Installations

Abstract

Abstract Over 50% of the offshore oil and gas installations in the UK Sector of the North Sea have now been operating for at least 20 years. Most assets are now approaching or operating beyond the original design intent. With the continuing rise in oil and gas prices and the advances in technology, there is an increasing requirement to extend the operational life of these assets. Coupled with this is the fact that most installations have seen considerable changes in the composition of the well fluids over the life of the field and there is an increasing trend for additional subsea tie-backs. All of these issues have raised concerns regarding the integrity and fitness for purpose of the structures and equipment for this extended life. As a result, the safety case regulations were modified to include a technical justification for extended operation and the Health & Safety Executive has recently launched the Key Programme 4 (KP4) to ensure that all duty holders have suitable management systems in place to adequately address the ageing related issues. This paper will outline a structured methodology that can be used to identify the issues which may prevent safe and reliable future operations of an offshore oil and gas installation. Some of the specific issues from previous ABB studies for offshore assets in the UK, Danish and Norwegian sectors of the North Sea will be outlined. These will include corrosion, obsolescence of equipment, changes in design duties, changes in oil or gas properties, availability of historic information etc. The paper will present a methodology for the evaluation of the risks associated with these issues and also outline how the recommended actions from such an approach can be used to help justify continued operations from a health & safety, environment and financial standpoint.