These sizes are outside of standard ANSI and MSS flange ranges, and posed significant technical challenges, as well as requiring a 20-year design life.
The closures were co-designed and supplied through Vector’s US partner LTS Inc., and will connect the Cleopatra and Cesar export pipelines to the Holstein, Mad Dog, and Atlantis platforms. With Thunder Horse these fields make up the Mardi Gras System, which is one of BP’s largest developments in the world, with nearly 2Bbrl of recoverable oil, and the most-significant find in the Gulf of Mexico’s history.
Key to the requirements was for the closures to be quick and easy to operate, but their size and weight made manual operation cumbersome and time consuming. Moreover, the barrels are vertical, making it especially difficult to open and control the function of the closure door, which weighs in excess of 1T on the 34-in. The solution was to automate the closures, enabling opening and closing with remote sensing from an integrated control panel. Each PowerLok can thus be opened in approximately five minutes significantly less time than the 6-8 hours estimated to assemble and bolt-tension custom-designed flanges.
Assured joint integrity was a further demand from BP, particularly with the closures being repeatedly operated; they were designed to the maximum ANSI pressure rating of 3,705psi, exceeding the operational requirements of the pipeline, and the bolting arrangement has been proven to provide consistent and safe joint integrity without the need for periodic tightening.
The technology is already drawing additional attention further orders for 32-in and 24-in PowerLok clamps have been placed with Vector by LTS for the connecting Mad Dog platform.