With the oil and gas industry’s push into new energy frontiers, the offshore pipeline industry is faced with greater technical challenges relating to pipelines and the expectation that it will optimise solutions to be cost-effective. DNV GL is launching three new joint-industry projects (JIPs) to help the industry address these challenges.
The first JIP will make pipeline free-span intervention less costly, the second will result in faster and more consistent pipeline repair, and the last will optimise the design of pipeline components faster.
DNV GL global director for pipelines Asle Venås said: "Offshore pipelines are the veins on an offshore field development and represent a large part of the total investment, and the value of the transported product can be enormous.
"DNV GL is committed to supporting the industry to work smarter, safer and greener. All three cooperation projects present an opportunity for the industry to work more efficiently, either through optimised and more reliable design, faster execution of projects or safer and more robust operation."
Free spans in trenches JIP
Gaps between the seabed and pipeline, known as free spans, can lead to vibrations that may damage the pipeline.
DNV GL oil and gas project manager Olav Fyrileiv said: "Lack of knowledge about the extent of vibrations in small gaps that typically occur on sandy seabeds means the industry is conservative and is potentially over-dimensioning designs and conducting unnecessary interventions.
"The DNV GL JIP aims to address this problem by developing improved free-span assessments, which will lead to fewer interventions and reduced cost."
The project comprises computational fluid dynamic analysis combined with a significant test programme and the outcome will be an extension of DNV GL’s Recommended Practice for Free-Spanning Pipelines (DNV-RP-F105). DNV GL has already partnered with Dutch pipeline operator BBL Company VOF and is now inviting other pipeline operators to also join the project.
Pipeline repair JIP
Maintenance and modification technology on offshore pipelines is developing to reduce downtime and accommodate deeper and harsher environments. Technology and operational experience have been developed through several projects, such as remote pipeline operations using hyperbaric welding and Statoil’s successful hot-tap operations in the North Sea.
DNV GL oil and gas project manager Dag Øyvind Askheim: "DNV GL is inviting the main players in the pipeline repair equipment sector to collaborate with us in reviewing recent developments in pipeline repair and maintenance.
"We plan to develop formalised criteria and procedures in an updated version of DNV GL’s Recommended Practice on Pipeline Subsea Repair (DNV-RP-F113). The aim is to reduce the time and cost spent on the design and execution of pipeline repairs."
Design of pipeline components JIP
Today, internationally recognised standards and recommended practices cover the limit state design of subsea pipelines. However, such design codes only provide high-level guidance on how to consider pipeline components within a pipeline system.
Currently, there is not a consistent and unified approach to the design of pipeline components. With modern pipeline standards, the pipeline design is optimised and this gap becomes even more pronounced. The objective of this JIP will be to develop an approach, based on industry experience and best practice, to pipeline component design that is compatible with a modern pipeline limit state design code, such as DNV-OS-F101.
DNV GL oil and gas project manager Jonathan Wiggen said: "The aim is to help prevent project delays, increased costs and, in some cases, compromised safety, which can happen when the interpretation of codes is stretched. We are inviting major players working with pipeline systems and components."