A.Hak Leidingbouw wins ISTT Award for rehabilitation project
A.Hak Leidinghouw was given the Project Award (Rehabilitation) for its completion of the Schoonebeek Pipeline Rehabilitation in the first half of 2016. The unique pipe-in-pipe rehabilitation project was completed on an existing 45 km pipeline in Schoonebeek, the Netherlands.
The project client, Nederlandse Aardolie Maatschappij BV (NAM), selected a trenchless pipe-in-pipe method to rehabilitate a production water pipeline. The pipeline is essential to NAM’s oil production location in Schoonebeek.
To complete the project a high density polyethylene (HDPE) pipe with steel reinforcements manufactured by FlexSteel was inserted into the existing steel pipe. The relining of the pipeline was carried out by A.Hak Leidingbouw, one of the shareholders of aQuaintance. Although a pipe-in-pipe project can hardly be called revolutionary, this project was highly complex.
The existing steel pipeline had a total length of 45 km and a very challenging curvature. A.Hak Leidingbouw constructed an elaborate test environment to deliver proof of the design concept. The expertise of A.Hak Leidingbouw’s sister companies and its Equipment Department was used to select and modify the equipment needed to get the job done safely, and in accordance specifications and planning.
NAM has been producing oil at the Schoonebeek field for several years. NAM intends to continue producing oil from this field for another 25 years. During oil production saline groundwater is extracted from deep layers of soil. This water is transported to the Twente region, where it is injected into depleted gas fields.
On 16 April 2015 NAM discovered a leak in the existing water pipeline in a field in the municipality of Hardenberg. NAM responded by shutting down all production activities. Inspections showed that the integrity of the inner lining of the pipeline was compromised unexpectedly by bacterial growths.
Without the possibility of transporting the saline water to the region of Twente it was impossible to produce oil. Therefore, NAM had to decide whether to replace or repair the pipeline before oil production from the Schoonebeek field could be resumed.
A trenchless solution
NAM decided the best solution was to move ahead with pipeline rehabilitation. The project work was to be carried out by aQuaintance, NAM’s contract partner for engineering, procurement and construction of onshore projects, formed by shareholders A.Hak Leidingbouw, Tebodin and Engie. Tebodin specialises in engineering, Engie is responsible for the locations and A.Hak Leidingbouw carries out pipeline work, including this particular relining project.
NAM and aQuaintance conducted extensive research into the possibilities which resulted in the decision to reline the existing pipeline, using a pipe-in-pipe method. A flexible HDPE pipe with steel reinforcements, manufactured by FlexSteel, was pulled into the existing pipe.
The FlexSteel spooled pipe technology was developed from more than 30 years of experience in demanding offshore environments. It combines the corrosion resistance and installation advantages of a flexible pipe with a core of steel.
Durable by design, it can be laid directly in rough terrain without affecting reliability. The use of this pipe greatly reduces the risks of future leakage because HDPE is far less vulnerable to corrosion and bacteria than a conventional steel pipe.
In theory a pipe-in-pipe rehabilitation was the best method to repair the pipeline. However, completing the project in a 45 km pipeline with numerous 40 degree and 10 degree curves had never been performed before. Therefore, the theoretical design needed testing to confirm that all calculations and assumptions would hold up during practical execution.
A.Hak Leidingbouw relied on the expertise of its sister company A.Hak Electron to utilise cable winches that are usually used to pull in high voltage cables. A test environment was built at the A.Hak workplace in Veendam to make sure that the cables wouldn’t damage the existing steel pipe, and that the winches would be able to pull the HDPE pipe through the curves.
To overcome friction, which was precisely measured during the testing, a dedicated machine was built to lubricate the steel pipe. Other machines were also modified by the A.Hak Equipment Department, to improve their performance for the specific job and to comply to the strictest of safety demands.
Pipe segments with lengths up to 180 m, carried on drum carriers with a diameter of 4 m, were transported to the work site by trucks. The execution phase of the project took approximately 6 months and was carried out in the first half of 2016.
Lloyd’s has already tested and approved the repaired pipeline, including approval of product, design and execution. After a final approval from Staatstoezicht op de Mijnen (Dutch: States Supervision of Mines) the pipeline can be commissioned. The project was carried out in compliance with international safety and quality regulations (API 17J) and Dutch regulations (NEN 3650).
For more information visit the A.Hak Leidinghouw website.
This article was featured in the Winter 2017 edition of Trenchless International. To view the magazine on your PC, Mac, tablet, or mobile device, click here.
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