Composite repair of sub-sea pipelines

The development of new deepwater oil and gas fields provide an opportunity for increased use of new materials. Conventional infrastructure is constructed using significant quantities of steel and concrete, which is becoming less practical in comparison to new light weight, easy to handle composites. When infrastructure needs to be repaired, there is often a requirement for underwater welding, which carries considerable occupational health, safety and environment (OHSE) risks. For this reason, moving away from traditional metal structures or repair technologies is increasingly attractive. In recent years a number of new water activated composite wrap materials have been developed for use in underwater applications. The materials properties that are required can be difficult to achieve and maintain over an extended period of exposure to the marine environment, though, so many research groups are working on this challenge. A comprehensive literature review has been undertaken to identify present state of the art ideas for the development of improved underwater materials and this will be discussed in the context of adhesive applications. Preliminary material characterisation work will be described where new resins have been formulated to perform well in marine environments and survive prolonged exposure to seawater. Experiments were carried out in artificial seawater and samples left to cure at a range of temperatures DSC and dynamic mechanical analysis (DMTA) were used to evaluate the crosslink density of the network and the glass transition temperature respectively, while FTIR was used to determine the chemical structure in the cured systems. Preliminary mechanical test results have shown significant improvement in strength for the new formulations compared to a set of control samples of commercially available materials.