Abstract

Subsea pipeline design involves detailed finite element analysis to assess the in-place response and ensure pipeline integrity. The complexity of modelling is continuously advancing to improve the accuracy and reliability of the design.

The typical approach involves a significant amount of manual modelling by skilled engineers. In Subsea 7, the automation of modelling and post-processing has proven to greatly enhance the design process to provide engineers a much more powerful and efficient toolset. Innovations have allowed complex modelling and data processing to be available to engineers of all levels of expertise.

This paper presents Subsea 7's recent developments in subsea pipeline design automation to increase the accuracy, efficiency and quality of pipeline design.

In-house developed software allows engineers to easily model subsea pipelines in their full 3D configuration. This includes route curves, 3D seabed profile and all associated features (e.g. buckle mitigation methods, anchors). Automated data processing presents results to users with user-friendly and powerful visualisations. Data processing includes code check calculations and free span assessments.

Introduction

Thermo-mechanical analyses are a crucial part of the subsea rigid pipeline design process. The in-place response under operational conditions must be evaluated to confirm the pipeline integrity throughout the design life.

The high pressure and temperature within a pipeline create a high axial compression. When pipelines are laid exposed on the seabed, buckles may develop along the length. Controlling these buckles is key to a successful design and compliance with design standards. If the pipelines are buried for protection, buckling is inhibited by the download forces generated by the cover. The engineering of these pipelines requires time intensive and advanced analyses to fully assess the solution and mitigate any likelihood of pipeline failure.

Similarly, On-Bottom Roughness (OBR) analysis requires the user to identify free spanning sections of pipeline along the route and conduct detailed analyses to determine whether any mitigations or rectifications are required to ensure an acceptable design.

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