The development of a non-intrusive method to evaluate residual pipe section after plastic deformation of pipelines has been investigated by Saipem. Experimental and numerical activities have been carried out to support this effort, involving full-scale four-point bending tests and Finite Element Analysis (FEA) fully reproducing the experimental setup, including pipe sample geometry and actual material behavior. The occurrence of localized strain in the load application points, that would have impaired the later use of the pipes in the field verification trials of the new non-intrusive method, was avoided by means of a careful selection of the pipe geometry and material and of the experimental configuration. All tests were successfully performed, producing in all cases a pipe with the target level of deformation, and showing good agreement with the FEA model.
Working in deep/ultra-deep water and harsh environments requires advanced engineering and installation capabilities to meet the challenges of laying heavy pipes and long catenaries in harsh meteo-ocean conditions. Dedicated vessels and special purpose equipment are needed in order to make viable offshore operations in a safe and reliable way, safeguarding the lay vessel equipment and preventing accidental damage or flooding of the pipeline.
During laying operations from a pipe-laying vessel, the pipeline piggability shall be guaranteed until complete deployment onto the seabed. The currently mechanical methods used by offshore industry to perform buckle detection present some operative drawbacks, particularly the potential damage of the pipeline internal coating. To overcome these issues, the possibility to develop a non-intrusive method to evaluate the residual pipe section after an incidental event causing a certain degree of deflection has been investigated by Saipem.
As a result, Saipem has developed a non-intrusive tool to monitor anomalies along the line, e.g. buckles, water intrusion and obstacles that may occur during pipelay operations. It can remotely investigate long stretches (up to some km) of the line, classifying and quantifying the measured anomalies.
