Effectiveness of using fibre-reinforced polymer composites for underwater steel pipeline repairs

Metal pipelines are the most efficient and safe ways for oil and gas transportation over a long distance. At present, almost all pipelines are made by ferrous steel which is sensitive to corrosion at harsh working environments, particularly in the presence of salty water and sulphur ingress media. For years, the most traditionally-credible solution for a damaged steel pipe is to remove the pipe entirely or just a localised damaged section and then replace it by a new one or cover with a steel patch through welding, respectively. Welding or fixing the steel patch is a bulky process especially if the location is underground or underwater. Thus, many researchers have been striving to find effective and safe repair solutions which are light, fast and easy to handle. Numerous literatures have shown that fibre-reinforced polymer-based composites can be effectively used for steel pipe repairs. Considerable research has been carried out on the repair of corroded and gouged pipes incorporating with fibre-reinforced composite wraps. This paper provides a comprehensive review on the use of fibre-reinforced polymer composites for in-air, underground and underwater pipeline repairs. Future developments and prospects on this are also discussed. Critical aspects of technical challenges, benefits and shortcomings in determining the feasibility and suitability for repair systems involving the composites are also presented.