Abstract: A subsea Christmas tree coupling having a radially outer connection, for example a tree surface and a conductor housing, adapted to make a rigid joint with a conductor casing. A radially inner connection, for example a depending skirt of the subsea Christmas tree, is adapted to make a sealed joint directly with a casing hanger assembly of a mudline suspension system. The invention thus substantially eliminates the use of additional hangers besides those of the mudline suspension system, simplifying the coupling assembly, and providing the possibility of reduced stackup heights. The relatively compact and simple coupling results in shorter installation times and lower costs. The rigid joint between the coupling and the conductor casing ensures that any external loading is transferred to the conductor casing.

Abstract: A subsea system comprises a central template that is piled into the seabed and carried wing modules that are connected to the template by hinges. This allows the template to be deployed and the wing modules attached subsequently or for the wing modules to be folded upwardly into a collapsed disposition as the template is deployed. In either case, the template can be deployed through the moonpool of a vessel and does not require a heavy lifting barge. An example of a module usable with the template is a hinge-over guidebase which can allow the commencement of drilling of a well while a manifold and christmas tree are being constructed for subsequent attachment. Thus, installation of the system is easy and drilling of the well can commence quickly.