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Nord Stream retrospective

Published by , Senior Editor
World Pipelines,

Ruurd Hoekstra, Maintenance Director at Nord Stream AG, talks about integrity and maintenance strategies for the Nord Stream gas pipeline: how is the operator tackling the first stages of integrity management?

Following the construction of the Nord Stream Pipeline from 2010 through 2012, Nord Stream AG has transitioned from being a project company to the operator of the 1224 km twin pipeline gas transportation system connecting Portovaya on the Russian Baltic coast with Lubmin, Germany. As an operator, Nord Stream AG is focusing on safely and reliably maintaining its main asset: the gas transportation system.

How is Nord Stream approaching integrity management for its pipeline?

Now that we are in the operations phase, integrity management – preserving the asset for long term operation – is the central engineering function within Nord Stream. We view integrity management as a holistic process, covering functions within the whole company, from compliance through financial departments. We began setting up the operations-phase integrity management during the project phase and it follows a standard quality process: Plan-do-check-act.

The first thought in terms of integrity management is: what could happen that endangers integrity, what would be the consequences and what is required to remedy the situation? We conducted a risk assessment, which in itself is a process involving many functions within the company, each contributing a perspective to the assessment, financial, management of changes to the system, inspection and associated personnel and equipment requirements, environmental and social implications. The important thing is: you need data to assess the condition of pipelines – so inspections are obviously central to integrity management.

What is Nord Stream doing in terms inspections and what has Nord Stream done so far?

For identified risk scenarios, an Integrity Management Plan is designed: which surveys and inspections are needed to gather what data; how to properly assess the results and what remedial measures and repairs are needed in each case, including what preparation is needed to ensure repair readiness.

Inspections are undertaken regularly to gather data on the condition of the pipeline and its components, and the subsequent data is analysed by us and our contractors in order to assess whether any remedial work is required.

We conducted the baseline surveys, both external by ROV and internal with an intelligent pig, in 2013. Both confirmed that the pipeline is in ‘factory new’ condition.

Last year, we conducted the first follow-up external inspection by ROV, both visual and geophysical. We compared the results to the baseline to see how the pipeline is behaving under continuous operation conditions. As expected, the pipeline is settling into the seabed. We also checked for foreign objects in the vicinity of the pipelines and found nothing unusual.

As expected, we are seeing that the pipeline is overgrown with small mussels in certain depths, forming an artificial reef for the species.

We will conduct further external surveys in summer 2015, to continually monitor the geophysical stability and position.

How is Nord Stream setting up its repair readiness and capabilities?

Thanks to a comprehensively engineered design; a high standard of material used for pipeline construction; carefully planned routing; and regular inspection and maintenance activities, a significant pipeline repair event is not expected during the pipeline system’s design life of 50 years.

For repair and remedial works, we are putting a lot of efforts into readiness.

We introduced a repair preparedness strategy designed to guarantee a level of preparedness and response capability in the event of an incident, to ensure that the asset can be recovered safely back to its normal operational performance in an efficient and reliable manner. We started with upfront development of procedures for a spectrum of possible repair cases and set up an organisational structure including internal functions for repair and qualified and trained personnel with the expertise to implement repairs in accordance to best industry practice.

An important part is also ensuring the availability of necessary spares and upfront investment in long lead items of repair equipment to be stored and maintained for the pipeline operational life. We are storing a variety of spare parts and 450 (equivalent to approximately 5.5 km) spare pipes near the landfalls for repair cases.

Agreements with appropriate industry specialist contractors are also a key element.

Written by Ruurd Hoekstra, Maintenance Director at Nord Stream AG and edited by Elizabeth Corner. This article was published in full in the August 2015 issue of World Pipelines. To read the full article, click here.

Part 2 coming soon.

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