Composite repair of through-wall defects in pipework – Analytical and numerical models with respect to ISO/TS 24817

Abstract

A major problem for the oil and gas industry is the repair of corroded steel piping. As a replacement of affected sections usually results in high expenses for the operator, rehabilitation methods which can be implemented on an operating pipeline are favoured by the industry. The application of overwraps made of Fibre-Reinforced Polymer systems offers such a promising method. In this work it is assumed that an overwrap is already installed, however, ongoing internal corrosion leads to a through-wall defect in the pipe. Hence, the fluid pressurises the repair and a detachment of the overwrap from the steel substrate can occur. This can even result in external leakage. In order to avoid this case of damage an analytical assessment approach is developed by means of Linear Elastic Fracture Mechanics and Finite Element Analysis. Subsequently, this approach is compared to the one given in the Code ISO/TS 24817 which is currently the mainly used code for the qualification and design of composite repairs for pipework.