Subsea 7 Limited

Subsea Deployment Systems Limited

Arnbjorn Joensen

Julek Romuald Tomas

Shona Margaret Manson

Emma Claire Taylor

Samuel David Irvine Paul

Dwayne Hewitt Hopkins

Nwabueze Samuel Ogbodo

John Joseph Ryan

Samuel David Paul

A method of dewatering a subsea pipeline bundle assembly before lifting the assembly from the seabed and an elongate carrier pipe comprising at least one internal fall that slopes downwardly towards a drainage outlet and at least one venturi formation that is aligned with the drainage outlet. The method comprises adding discrete buoyancy to the elongate carrier pipe that elevates the carrier pipe disposed between drainage outlets of the assembly. Each elevated portion defines inclined falls that slope downwardly in opposed longitudinal directions toward the respective outlets. Water within the carrier pipe drains down the falls toward the outlets. Injecting a dewatering fluid into the carrier pipe promotes expulsion of water from the pipe through the outlets by downward displacement of the water. Drainage may be assisted by a venturi effect driven by accelerating the flow of the dewatering fluid at a location in line with an outlet.

Subsea infrastructure and method of decommissioning subsea infrastructure

A method of installing a production buoy at a subsea anchoring location is disclosed. The method includes floating a production buoy over a subsea anchoring location. Then, hanging at least a tether off the production buoy such that the or each tether extends from the production buoy towards the subsea anchoring location occurs. The method includes submerging the production buoy to a depth which allows connection of the or each tether to the subsea anchoring location. An apparatus suitable for use with this method is also provided.

Method of installing a buoy and apparatus for tensioning a buoy to an anchoring location

There is provided a method and apparatus for lowering and/or raising a load or structure to or from the bed of a body of water. The apparatus comprises a buoyancy apparatus configured to be coupled to a load, and having positive buoyancy sufficient to lift the load. At least one receptacle is provided on the apparatus for receiving a control weight lowered from a vessel to lower or raise the assembly. The lowering method includes forming an assembly from a buoyancy apparatus and a load and submerging the assembly to a position at a first height above the bed. In a preferred embodiment the assembly is submerged by a clump weight tow system. A control weight is deployed from a vessel to the assembly to overcome the positive buoyancy of the assembly and thereby lower the load from the first height to the bed. The raising method reverses the steps of the lowering method.

Method and apparatus for subsea installations

A riser configuration having a rigid riser portion and a flexible riser portion. The riser configuration also includes a subsea buoy across which the riser portions are connected. Buoyancy means are mounted on the flexible riser portion.

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Aberdeen, United Kingdom

Arnbjorn Joensen