The first of a total of 14 Christmas trees, supplied by FMC Kongsberg, for the Ormen Lange project was positioned in the week of 20 November at a depth of 850m in the Norwegian Sea. Hydro’s Thomas Bernt, who is responsible for subsea operations, says that it is the world’s biggest Christmas tree, or wellhead valve and piping assembly, ever used in an offshore project. An oil industry “Christmas tree” consists of valves, safety systems, fittings and requisite measurement instruments connected to the templates. Considerable dimensions are required on Ormen Lange, and the first Christmas tree weighs as much as 65 metric tons and is measures 4.0m x 4.5m x 3.9m. It was installed on Template A and connected to the manifold. The tree was pressure tested against the manifold and everything was found to be in order. The Christmas tree consists of two sections, the tree itself and a choke module. The next step is to finalize drilling of the well and prepare it for gas production (completion). Remaining drilling will take place by passing the drill string through the Christmas tree and down into the reservoir.
