Creating a local residual curvature during S-lay pipeline installation by lowering the stinger

Marine pipelines are often operated at high internal pressure and temperature. This loading condition results in the development of axial compressive forces that can cause the pipeline to buckle globally. Global buckling occurs when significant lateral motion is present in the pipeline and excessive feed-in occurs at that specific location,...

Partially Displacement Controlled conditions in the overbend: During S-lay pipeline installation

The S-lay pipeline installation method is characterised by its fast installation process and its application in all water depths. Offshore standards and design codes provide local buckling checks for combined loading criteria for load controlled and displacement controlled conditions, where a load controlled condition is defined as a case in...

Significance of Active Tension Compensation during S-lay Pipeline Installation

During S-lay pipeline installation, tension fluctuations in the suspended pipeline are compensated by the tensioner system on the vessel. The goal of this thesis is to answer the questions: to what extent does the active tension compensation (ATC) influence the pipeline integrity during offshore installation. Secondly, which tensioner model...

Vessel motion based criteria for pipeline Abandonment and Recovery operations

Offshore pipeline installation is limited by pipeline integrity during the laying process. Pipeline integrity is evaluated with the help of buckling checks, which help determining the feasibility of pipeline installation for a given sea condition. The operational limit of pipeline installation is determined during project preparation, by...

Pipeline Rotation Analysis & Modeling During S-Lay Installation

The safety of offshore pipelines during installation has drawn a great deal of attention due to the combined actions of high external pressure, axial tension and bending moment. Subsea pipelines have the tendency to rotate during installation. This rotation can have multiple causes which are interfering with each other. During S-lay installation...

Project Specific Vessel Motion Based Abandonment Criteria

When harsh weather conditions are expected during an offshore pipeline operation, the decision to start the abandonment procedure has to be taken based on pipeline integrity limits. The pipeline integrity which is analysed by a maximum design sea state does not correspond to the situation offshore, because sea states always occur in a different...