DNV pipe-soil guidance improves submarine pipeline safety
Oslo-based DNV GL has developed a recommended practice (RP) offering guidance and recommendations within a geotechnical framework for submarine pipe-soil interactions. These are important because they can lead to severe displacements and impaired pipeline integrity but assessing them can be complex and the results uncertain due to lack of data. Based on existing guidance and recent research, the RP details how to safely avoid over-conservatism and highlights the importance of geotechnical input in projects.

 

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Soil characterisation and pipe-soil interaction assessment are important parts of any pipeline project (photo: DNV GL)

Depending on the interaction between the pipe and soil, submarine pipelines, both exposed and buried, may be subject to severe displacements and impaired pipeline integrity. Soil characterisation and pipe-soil interaction assessment are therefore important parts of any pipeline project. DNV GL now launches a new recommended practice (RP), DNVGL-RP-F114 ‘Pipe-soil interaction for submarine pipelines’, solely dedicated to the interaction between the pipeline and the soil.

Pipe-soil interaction assessments are usually far more complex and there can be more uncertainty on the results compared to traditional foundation design. This is due to limitations in soil data along the pipeline route, difficulties in characterisation of the soil close to the seabed, dynamic pipeline installation and subsequent design scenarios involving large displacements.

To manage these uncertainties for improved, safe and cost-efficient pipeline design, geotechnical knowledge and guidance is key. However, until now a dedicated industry standard on pipe-soil interactions has been lacking. DNV GL has collected, aligned and reviewed existing guidance, considering recent research, and developed the new DNVGL-RP-F114. The RP provides holistic guidance and recommendations within a geotechnical framework.

Jens Bergan-Haavik, Senior Geotechnical Engineer, DNV GL – Oil & Gas, says, “Geotechnical competence is required to understand the complex soil behaviour close to the pipe during installation and operational conditions, in addition to managing the inevitable uncertainties related to limited soil data and to simplifications in the engineering models. The pipe-soil RP highlights the value of geotechnical input in projects to ensure robust pipeline design solutions. The RP also provides recommendations on how to safely avoid over-conservatism through specification of state-of-the-art laboratory tests.”

Cathrine Torp, Communication Director, DNV GL – Oil & Gas, says, “According to DNV GL’s seventh annual benchmark study, Short-term agility, long-term resilience, 27% of senior players in the sector believe there will be a significant global increase in the approval of new offshore oil and gas pipeline projects globally over the three years. As increased knowledge is the best cure for managing uncertainties, this new RP will support pipeline projects with the insights they need for safe and efficient installations and operations.”