The recent installation of SPS on the Bohai Shi Ji, enabled the FPSO to remain in operation during vital repairs, saving time and money for owners, China National Offshore Oil Corporation (CNOOC).
Our team of experts recently conducted repair work to a corroded cargo oil tank on CNOOC’s FPSO, Bohai Shi Ji. The inner bottom plating in the tank required a permanent repair solution that would avoid disrupting FPSO operations causing costly time out of service. As a durable, class-approved material, which requires no hot work, our structural composite, Sandwich Plate System (SPS), offered the ideal structural repair and strengthening solution.
A proven alternative to traditional crop and renew techniques, SPS has been used in the industry for decades and offers a fast, non-disruptive solution, which delivers improved strength when compared to conventional steel structures. As the corrosion occurred in the double bottom water ballast tank, SPS was applied on the deckhead in the water ballast to reinstate the inner bottom plating of the cargo oil tank. It is the first SPS no hot work ‘underlay’ application. With this application the double bottom water ballast tank and cargo tanks can remain in operation while the reinstatement process is on going.
Unlike traditional steel, SPS can be installed without hot work, enabling the Bohai Shi Ji to safely continue operations while repairs were completed to one of the cargo oil tanks. SPS was installed using structural adhesives, on various portions of the inner bottom structure to reinstate the existing plating that had areas of localised corrosion. This SPS solution included a combination of pre-welded top plates to the perimeter bars, bonding and bolts fixing the perimeter bars to the existing inner bottom stiffeners; elastomer was then injected into the cavities upside down.
The composite panel created by the bonding of the solid elastomer core, to the existing top and bottom plates, reinstated the strength of the structure. By using SPS as a repair solution, CNOOC not only saved valuable time and money, but improved the lifetime performance of its oil cargo tank.