Structural integrity monitoring: Review of the last 10 years of technological development for offshore oil & gas platforms

The majority of offshore platforms have passed their design lives. The ageing related problems and how to manage these problems is a key concern for oil and gas offshore structures. For this reason, offshore structures, especially fixed jacket platforms, should be appropriate conditions for its intended use through their service life. The need to maintain offshore structural integrity has been increased in recent years and plays a significant role in continuous integrity and life extension. Early detection of damaged items can prolong the life of platforms by replacing them and results reducing maintenance expenses and increasing safety. Therefore, SI monitoring techniques, especially non-destructive techniques (NDT), are widely used for the early detection of damage in offshore structures. The purpose of this thesis is to analyze the last decade (2010-2021) of technological development within SI monitoring techniques and how these techniques can be used to increase the structural integrity of oil & gas platforms. There is exhaustive report called “Structural Integrity Monitoring: Review and appraisal of current technologies for offshore application”, However, it had been published more than 10 years and new work is needed to be performed for structural integrity of platforms. Therefore, the objective of this thesis is to serve as an overall update of existing techniques, both already-existing techniques that further developed in last 10 years and new proposals as well. In this work, more than 70 papers, book and articles are reviewed to get most applicable Structural integrity monitoring techniques in offshore industry. This study will also discuss the concept for monitoring existing ageing jacket platforms in more detail. There are five chapters in this study work: Introduction, five chapters with 2 case study conclusion with future recommendation, two appendices. The first chapter is composed of a literature survey of current SI monitoring in offshore structures, SI management, codes, applicable standards and a brief description of offshore structures’ design. The fundamental information about potential loads, damage characteristics and failure modes of the jacket structures are then clarified in Chapter 2. Chapter 3 provides a qualitative review of SI monitoring techniques mainly used for damage detection, position of floating structures as well as advantages, limitations, monitoring capabilities, maturity in offshore industry, requirements for use and probability of detection (PoD) of these techniques. Chapter 4 describe the development of SI monitoring techniques for critical items in offshore platforms for the extension of their service lives. A specific case studies related to crack damage in the jacket platform of the Caspian Sea and proper localization of Acoustic emission sensors in offshore jacket platform are presented in the last chapter. Conclusion and two appendices are also generated in this thesis