An apparatus for using acoustic energy to provide operational power to a sensor of a subsea installation, such as a subsea well installation, is provided. In one embodiment, the apparatus includes a subsea installation in a body of water, with the subsea installation including a sensor and an acoustic receiver. The apparatus also includes an acoustic transmitter for transmitting acoustic waves to the acoustic receiver using the body of water as a transmission medium. The acoustic receiver is coupled to the sensor so that the sensor can be powered with electricity generated from the acoustic waves received at the acoustic receiver from the acoustic transmitter. Additional systems, devices, and methods are also disclosed.

A clamp for a flexible pipe is provided that provide a load bearing flange on the flexible pipe permitting buoyancy jackets to be joined thereto. The clamp has a longitudinal axis arranged to extend along the length of the flexible pipe and a radial axis being perpendicular to the longitudinal axis. The clamp includes: a plurality of separate clamp elements being supported together in a radial array extending at least partially around the longitudinal axis; engagement means located between neighboring clamp elements to movably interconnect the clamp elements; and a strap being adapted to surround the clamp elements, in use for exerting a compressive force thereon. Also provided is a clamp element for use in the aforementioned clamp.

A rupture assembly that may be employed in the oilfield industry facilitates the deployment of a tubing string in a well. The rupture assembly may be installed at the bottom of the tubing string for the purpose of trapping air in a lateral section of the tubing, between the rupture assembly and an upper sealing assembly. As a result, the buoyant force in the lateral section reduces the drag encountered while running the tubing through the casing, thereby significantly reducing rig time, or permitting operations where none were possible previously. Once at landing depth, surface pressure may be added to burst and remove the seal and rupture assemblies.

A flexible elongate element for installation in a body of water to extend between a seabed connection device and a unit arranged at the opposite end of the flexible elongate element. At least one lateral displacement device is connected to a portion of the flexible elongate element and configured to displace at least a portion of the flexible elongate element a lateral distance away from a first axis extending between the seabed connection device and the unit, the at least one lateral displacement device including a spring member. The flexible elongate element may be a flexible riser, umbilical, hose, or cable.

An offshore well system for a subsea well, including a floating platform, a drilling riser system connected with the well for drilling operations, and a production riser system connected with the well for production operations. The drilling system also includes a riser tension system. The riser tension system is capable of compensating for movement of the platform while adequately tensioning both drilling riser system and the production riser system when each is connected to the well.

An underwater facility (18) for the gas/liquid separation of a multiphase hydrocarbon mixture includes an underwater supply conduit (16) and a longitudinal separation chamber (26) intended to be installed substantially vertically, the separation chamber (26) having a lower end (30) and an opposing upper end (28), and an intermediate separation area (32), the separation chamber (26) further comprising an injection conduit (34) connected to the supply conduit (16), the injection conduit extending longitudinally into the intermediate area (32), the injection conduit having a tubular wall and a free opening that opens towards the upper end (28). The tubular wall is continuous to be impervious to the multiphase hydrocarbon mixture.

A riser assembly and method of supporting a riser assembly are disclosed. The riser assembly includes a riser; at least one buoyancy compensating element attached to the riser; and at least one damped biasing element for controlling movement of the riser about a neutral position with respect to an adjacent underwater structure. The biasing element is directly or indirectly connected to the riser and is directly or indirectly connectable to the adjacent underwater structure.

A buoyancy device (1) comprises a support structure 2, which can be connected to an underwater application (3) and one or more buoyancy spheres (4) having a specific weight of less than 500 kg/m.sup.3 connected to the support structure (2) and having a light metal spherical shell (5) defining a spherical inner volume (6) and which has an outer diameter (d) greater than 0.5 cm, and a radial thickness (t) greater than 0.08 mm, wherein the spherical shell (5) is obtained in one piece in nano-crystalline metal with an average grain size of less than 1000 nanometers.

A flotation system includes one or more floatation modules, each having a first section and a second section, each having an internal core made of a buoyant material. The first section includes two end faces and a projection extending from one of the end faces. The projection has a contoured profile. The second section includes two end faces and a reciprocal recess in one of the end faces. The end faces of the first section engage the end faces of the second section such that the projection engages the reciprocal recess in a mating engagement. The outer surface of the flotation module include one or more grooves providing a pathway for the flow of circulation fluid. The floatation system may be attached to a tubular string during inner string cementing operations to reduce the load applied to the platform.

A marine riser system, a buoyancy system, and a method of buoying a body. A riser joint includes a body, a buoyancy module, a thrust collar, and a reaction collar. The buoyancy module is coupled around the body and configured to produce a buoyant force when submerged at a subsea location. The thrust collar is coupled around the body and engaged with the buoyancy module to transfer the buoyant force to the body. The reaction collar is engaged with the body such that movement of the buoyancy module is restricted by the reaction collar.