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MAXLOCK™ Centralizers utilized to land screen completion successfully at TD in challenging formation
Chalk screens. Composite centralizers. Completion

4-1/2" MAXLOCK™ Centralizers installed on the screen joints above and below the screen jacket


For the first time in the history of the field, the operator planned to run a screen lower completion in an unstable chalk formation on the Norwegian Continental Shelf. It was understood from the outset that failing to reach TD with the screens was a major concern. Additionally, it was anticipated that the screens may require to be rotated in order to reach TD.


Two key issues were presented, firstly the need for an extremely low friction centralizer in order to reduce drag forces and also rotational friction. Secondly, the screens would require the centralizer to protect them from damage while running in hole. It was anticipated that tight spots would be encountered while running in hole so a centralizer with high holding force was essential to prevent load being transferred to the screen.



Marwell AS in cooperation with our partners Maxwell Oil Tools delivered a MAXLOCK™ centralizer design which was fit for purpose. The centralizers are constructed from layers of carbon fiber and Kevlar with an outer layer containing a low friction ceramic material. These layers are formed into a centralizer shell in a factory with the addition of temperature and pressure. The centralizer shells are then bonded directly to the base pipe on location. The installation process is mobile and can be carried out at a location which suits the client. 


The key benefits of the MAXLOCK™ centralizer in this application were its high holding force and its low friction characteristics. The holding force of this 4 1/2” centralizer was in excess of 40,000 kg. This would later prove critical during the screen running. The MAXLOCK™ centralizer also provides a 40% reduction in friction over that of a standard steel centralizer. When rotation is planned for or expected then a solid bonded centralizer will rotate with the liner and thus aid in transporting cuttings from the leading edge of the centralizer to the trailing edge. This effectively reduces the drag forces while running in hole with rotation. These characteristics combined meant that the MAXLOCK™ was the ideal centralizer for this type of application.


The screens were run successfully to TD at 5000m MD as planned. Stringers were encountered in the wellbore and the string was worked down with 25-34 kNm of torque, 5-20 MT of weight and 10 rpm. The MAXLOCK™ centralizers were subsequently identified as the ideal solution for upcoming wells in the field.




Marwell is an independent company specialising in wellbore construction and completion equipment. Established in 2019 in Stavanger, its goal is to bring new and innovative tools to markets where they are not yet available. Collaborating with some of the industry’s leading suppliers and service companies, Marwell’s expert engineering team further develop field proven technology to deliver unique and tailored solutions.


Saving operators time and money, while also improving performance, Marwell’s speciality lies in its well-first thinking, offering a bespoke approach to ever-more complex problems. Its key products include: Composite Centralizers, Casing Equipment, Sand Control and Downhole Monitoring. Marwell has offices in Stavanger and a dedicated installation facility in Dusavik, Norway. For more information on Marwell AS visit


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