Material-Loss Estimation for Pipes

Metal loss of the internal wall of pipes can be caused by corrosion or erosion. Investigation and monitoring of these factors for the subsea pipelines are a very important issue because it can be possible cause of the pipe leaks and its associated hazards. According to statistics, up to 40% of offshore pipeline failures are associated with corrosion related issues. There are a lot of methods that can be use for inspection and diagnostics of the pipe, but most of them are not easy to apply for deepwater pipeline environments.

The following work provides a new method of estimation metal loss in a pipe. The proposed scheme is to utilize pipe hoop strain in order to estimate metal loss dimensions. There are some factors significantly influencing on the hoop strain: internal and external pressure, wall thickness, temperature, etc. It’s important to study all of it for evaluation of correct detection and estimation feasibility. We conducted numerical pipe modelling to evaluate how internal metal loss affects to external strain reading as a function of pressure and temperature. As the results of analysis, new methodology for determination of corrosion and erosion parameters was proposed.

Key words: metal loss, pipe corrosion, erosion, strains, subsea, hoop sensor