Abstract

The reel-lay installation process for low diameter pipeline is one of the most effective and economical subsea pipeline installation process. During reel-lay installation, the pipe is reeled, unreeled and straightened in loading cycles.

These successive straining of pipe induce local stress beyond elastic domain in the pipe section. Ovalisation due to Brazier effect is a key mechanical parameter to monitor the integrity of pipelines installed by reeling, as well as impacting mechanical performance for the in-service life. Installation JIP – Guideline for installation of rigid pipelines – limit state criteria (DNVGL 2014) has confirmed that, employing simpler elastic-perfectly plastic or Rambert Osgood material models, the FE simulation yields larger peak and residual ovality prediction than mechanical test counterparts. The oil and gas industry needs accurate FE prediction to simulate the reeling process with complex material property variations to achieve the more accurate prediction results.

The development of an in-house material model was previously published, introducing a subroutine to serve the purpose of the project orientated and task specific reel-lay simulation subject to cyclic straining. Since then, laboratory trials have been conducted to calibrate the model based on actual material properties compiled in an in-house data library. Pipeline reeling FE analysis employing such material model have also been verified against previously published laboratory test and FE simulations results.

Verifications and validations of the FE prediction employing the developed material model have shown that the in-house material model is suitable for reeling analysis subject to cyclic straining in reeling with very much improved simulation accuracy comparing with the published predictions in literature. This paper focuses on demonstrating the findings and achievements from the pipeline reel-lay FE simulation models employing the developed in-house material.

Small-scale material property tests and full-scale pipe bending tests to calibrate the in-house material model and validate the FE model are ongoing with variation of the following parameters: material property, diameter, wall thickness, plastic moment mismatch, with /without CRA liner. The reported research result is part of the on-going research and development project and further findings will be reported in due course.

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