Abstract: A mechanical actuator for moving a shaft axially has a motor driving a gear assembly giving a mechanical advantage of at least 30:1, preferably 50 to 150:1. The assembly drives an internally screw threaded sleeve on external screw threads of the shaft so that rotation of the sleeve moves the shaft axially. A stop connected to a gear of the gear assembly for the sleeve ensures that it is the shaft that moves.The actuator is suitable for all valves, chokes and control mechanisms for oil or gas production, particularly sub-sea production and the motor is preferably a reversible DC electric motor. The mechanical advantage allows heavily loaded shafts to be moved with low power input.When applied to spring loaded fail-safe valves the stop for the sleeve may be one or more moveable locking dogs actuated by the gear assembly. The gear assembly acts as a differential transmitting torque either to the gear wheel actuating the stop of the gear wheel rotating the sleeve.

Abstract: An annulus shut-off mechanism with fail-as-is logic suitable for use for example, in a concentric tubing hanger of an oil well, particularly a sub-sea well, has an enclosure across the annulus with inlet and exit ports, a sleeve with an aperture that slides within the enclosure, primary means for sliding the sleeve in the enclosure to bring the aperture into alignment with the inlet and exit ports and secondary means for sliding the sleeve in the event of failure of the primary means. The primary enclosure and sleeve are sealed from access to annulus fluids and may be vertically orientated in the tubing hanger. The secondary means may be a secondary enclosure with a secondary sleeve which can pull or push on the primary sleeve. Both primary and secondary means can be operated by hydraulic pressure, but the two means are independent and the secondary means may be located in a well part other than the tubing hanger.

Abstract: A vertical separator for separating crude oil into liquid and gas phases composed of an outer casing and two further sets of concentric tubing to enclose two annuli and a central passage, one annulus having an inlet to receive crude oil, the other annulus having an outlet for separated gas, each at the top of the separator. The central passage collects produced oil with a pump near its base and a pump drive pipe extending up it. The crude oil may flow down its annulus with a swirling motion which can be induced and assisted by a tangential inlet, and/or a cyclone at the top, and one or more helices in the annulus. The separator may be used for underwater wells and may extend partially or wholly into the sea bed with a protective cemented external casing around it.

Abstract: An operator for levelling a drilling or production template on the sea bed is formed from a rotatable hydraulic cylinder, a piston within the cylinder to which hydraulic pressure can be applied, and a drive shaft from the piston to a screw jack. Hydraulic pressure applied to the piston counteracts the weight of the template so that the operator can rotate the screw jack with relatively little torque. The operator may fit into a housing of the template through an intermediate housing. The operator and the intermediate housing may be releasably locked to each other and the template so that they can be recovered for re-use. A cementing/retrieving tool and a suspension tool may be used in combination with the operator.the screw jack may bear onto a mud mat or pile of the template.

Abstract: An insert choke for a sub-sea oil production module has a body and releasable latch for locking it into a housing of the production module, and a variable choke constriction within the body which can be adjusted by a screw-threaded stem co-operating with a screw threaded member which can be rotated manually, by an ROV, or by an associated choke control module.The associated module, if used, fits over the insert choke and has releasable latches for locking it to the choke, and gearing and motor(s) for rotating the screw threaded member and adjusting the choke. Hydraulic cylinders and pistons actuate both the releasable latches of the choke within the choke housing and the latches for locking and unlocking the choke to and from the control module.

Abstract: A sea bed oil producing and processing complex has a template with three bays housing pairs of modules, viz, well, gas and oil production modules. The complex includes a separator for separating oil and gas and a pump for the produced oil, and bars having pipework to carry fluids between the pairs of modules and to despatch separated gas and oil. Saddles may carry fluids across between individual modules of a pair and the complex may have facilities for artificial lift, water injection, chemical fluid injection and for test fluids. Multiples of the three bays and pairs of modules may be within a single template and a number of modules may surround a central piping template. The complex can be services and maintained in a diverless mode using a monohull vessel and an ROV.

Abstract: An electrically conductive coupling, suitable for passing an electric current to or from an underwater well or underwater equipment comprises:(a) an outer body having, on its inner surface, a recess,(b) an inner body having, on its outer surface, a recess, the recesses being positioned so that they are aligned when the inner and outer bodies are mated to form an annular space,(c) a resilient non-conductive member associated with the outer body having at least one inset conductive contact,(d) a resilient non-conductive member associated with the inner body having at least one inset conductive contact, the two conductive members occupying the annular space and providing, through their inset conductive contacts an electrical path between the outer and inner bodies, and(e) a passage for dielectric fluid to pass from the inner to the outer body or vice versa between the resilient non-conductive members and around or through the contact surfaces of the inset contacts.

Abstract: A sub-sea oil production system has a three-dimensional template with a framework of vertical and horizontal members. These members enclose one or more production bays each of which has a well slot and a manifold slot. Within each bay a well tree module may be installed vertically above the well slot and a manifold module vertically above the manifold slot, with a production bridge module linking them. The template and the modules are designed to be transported and installed by a semi-submersible drilling rig without the use of divers or guidelines. All access points are at the top of the modules so that the modules can be inspected, tested and serviced by a remotely operated vehicle, which can perch on raised guides on the top of hinged covers of the framework.

Abstract: A screw jack for levelling a subsea template comprises(a) a guided entry adapted to receive a flat-sided drive shaft,(b) an inner screw adapted to be rotated by the drive shaft,(c) a non-rotatable inner housing, through one end of which the screw is threaded,(d) a non-rotatable outer housing, against one end of which the screw bears, the outer housing being axially moveable relative to the inner,(e) a base against which the inner housing rests and(f) one or more projections on the outer housing adapted to bear against corresponding projections on the template.The arrangement is such that rotation of the drive shaft causes relative axial motion between the inner and outer housings. The jack is suitable for use in diverless systems.