Abstract: A method of installing a socket with a socket contact on an underwater plug with a plug contact is provided so as to establish conductive contact between the socket contact and the plug contact. The socket is disconnectably attached to a recoverable fluid exchange unit and the socket engages with the plug to establish the conductive contact between the socket contact and plug contact. The recoverable fluid exchange unit is then operated to substantially replace a first fluid within the socket with a second fluid from the recoverable fluid exchange unit.

Abstract: A system for separating fluids from a hydrocarbon well production fluid mixture at a subsea location has a centrifugal separator (16) for separating the mixture into gas and liquid. A hydrocyclone separator (32) then separates the liquid into oil and water and an oil-in-water sensor (38) detects the amount of oil in water leaving the separator. If the sensor (38) detects that the water contains more than the prescribed amount of oil, the water is recirculated through the hydrocarbon separator (32) for removal of further oil form water. The hydrocyclone separator (32) has a level interface sensor (66) and if this sensor detects that the oil/water interface is not within prescribed limits for optimum separation of the oil and water, the amount of oil removed from the separator is adjusted until the oil/water interface is within the prescribed limits.

Abstract: A substantially underwater system comprises a plurality of retrievable substantially autonomous subsea modules (12, 13, 17, 18) and switchgear (15, 16, 21a . . . h). A host facility (6) and the modules are connected in series so as to form a circuit, the host facility providing power to all of the modules. Operation of the switchgear electrically isolates a module or a plurality of serially adjacent modules so that the module or modules can be removed without cutting off the power supply to any of the remaining modules of the system. Module based parts of the switchgear (21a . . . h) only or a combination of module based parts (21a . . . h) and host facility based parts (15, 16) of the switchgear are actuated depending on which module or modules are isolated and removed.

Abstract: To install a modular seabed processing system (1) on a seabed, a monopile foundation (3) is first lowered down and driven into the seabed. A docking unit (4) is lowered towards the installed foundation (3) so that a mating clamp system (6) mounted on the docking unit is aligned with a spigot (5) on the foundation. The clamp system then clamps the spigot to fix the docking unit onto the foundation. Flowlines (2) and an electrical power connector plug (18) are connected to the docking unit. A first retrievable substantially autonomous module (8) is lowered and connected to the docking unit (4) by a multi-bored connector (10, 11) and the plug (18) on the docking unit is engaged by a corresponding socket (17) on the module. Isolation valves (14, 16) in the docking unit and module are opened so that the module (8) is able to act on fluid received from the flowlines (2) via the multi-bored connector (10, 11).

Abstract: A single well development system has a base structure (8) through which the well is drilled and completed by means of a wellhead (6). A retrievable Christmas tree module (10) containing a Christmas tree (12) connected to wellhead connector (14) is mounted on the base structure (8) by the wellhead connector (14) so as to receive well fluid from the wellhead. The module (10) contains two fluid processing separators (16) for processing fluid received from the well via the wellhead (6) and the Christmas tree (12). In a modification, additional modules are mounted on the base structure and each additional module has a fluid processing separator (16), and the Christmas tree module routes production fluid to the separators via the base structure (8).

Abstract: Water is supplied from a host facility (2) to a pump (10) in a seabed facility (5) via a connecting pipeline (6). The pump (10) pumps the water to a higher pressure, and injects the pumped water into a hydrocarbon reservoir at a pressure higher than the pressure of the fluid in the reservoir so that it drives production fluid there to the host facility (2).

Abstract: A mixture of fluids is conveyed from a hydrocarbon reservoir and comprises gas and slugs of liquid. The mixture is passed through a slug catcher vessel (12) which temporarily retains the slugs of liquid. The gas is passed through a gas compressor (18) and the resulting pressurised gas is then conveyed to a remote location. When a liquid slug is detected in the slug catcher vessel (12), liquid is drawn from the vessel by an injector device (24) and entrained into the flow of gas downstream of the gas compressor (18) until the level of the interface between the gas and liquid in the vessel reaches a sufficiently low level. The system may alternatively be configured to accommodate a flow of liquid containing slugs of gas.

Abstract: A system for separating fluids from a hydrocarbon well production fluid mixture at a subsea location has a centrifugal separator (16) for separating the mixture into gas and liquid. A hydrocyclone separator (32) then separates the liquid into oil and water and an oil-in-water sensor (38) detects the amount of oil in water leaving the separator. If the sensor (38) detects that the water contains more than the prescribed amount of oil, the water is recirculated through the hydrocarbon separator (32) for removal of further oil form water. The hydrocyclone separator (32) has a level interface sensor (66) and if this sensor detects that the oil/water interface is not within prescribed limits for optimum separation of the oil and water, the amount of oil removed from the separator is adjusted until the oil/water interface is within the prescribed limits.

Abstract: A subsea hydrocarbon reserve is exploited by intially drilling a first well (4) from a floating drilling vessel (2). A tree (8) is then installed on the well (4) and a production riser (10) is established between the well and the vessel for transferring production fluid from the first well (4) to the vessel (2) from where an off-loading hose (12) conveys the production fluid to a tanker (18). Production fluid is then extracted from the first well (4) via the production riser (10) which is of sufficient flexibility and length to permit the drilling vessel (2) to move between appropriate locations to drill further wells (4′, 20).

Abstract: Method and apparatus for assisting the flow of production fluid from a hydrocarbon wellbore (4) to a remote host facility (16) including a separation facility (6) situated close to the wellbore (4). Jetting fluid is supplied initially from the host facility (16) to a downhole jet pump (14) via the separation facility (6) for assisting the flow of production fluid from the wellbore (4) to the separation facility (6) where the resulting mixture enters one of two parallel gravity separation chambers (32). Separated jetting fluid (60) is recirculated to the jet pump (14) via a pump (38) and production fluid is routed to the host facility via a production pipeline (18). A jetting fluid supply pipe (20) can be of relatively small diameter and the production pipeline (18) does not have to be enlarged to accommodate jetting fluid returned to the host facility (16).

Abstract: A hydrocarbon extraction system (1) comprises a host facility (2), a wellhead tree (3) and a retrievable electrical power connection/control module (4). The module has a load (12) and is connected to the host facility and the tree via first and second wet mateable connectors (6, 8) respectively. The module also has qwitchgears (14, 15) controlled by the load for isolating the load from the host facility or the tree. The host facility is arranged to provide power to the module, and to the tree via the module when the switchgears (14, 15) are closed, and the load (12) of the module is arranged to control the via one (15) of the closed switchgears.

Abstract: Method and apparatus for assisting the flow of production fluid from a hydrocarbon well to a remote location in conditions in which gelling or solidification is a problem. The method involves adding dilution fluid (60) such as water, to production fluid from a wellhead (4) in a first sub-system (8) close to the wellhead (4), conveying the mixture to a second sub-system (14) where the dilution fluid (60) is separated from the mixture in a separator chamber (38) as a consequence of their different specific gravities, recirculating the separated dilution fluid back to the first sub-system (8) and adding it to further production fluid from the wellhead (4). The requirements for pipeline heating, chemical injection and conveying large volumes of dilution fluid to a host facility can be avoided by the invention.

Abstract: A method of controlling flows from plural hydrocarbon extraction wellhead trees (50, 52, 54, 56) in an extraction system including plural wellhead trees (50) connected by a pipeline network (60, 62, 88, 104) to a host facility (64) via a manifold system (130, 132) situated remotely from the host facility (64). Each wellhead tree (50) has a production outlet connected by a production conduit (88) to the manifold system (130, 132) and a test flow outlet (76) connected by a test conduit (104) to the manifold system (130, 132). Wellhead tree outlet valves are operable to divert the flow from one wellhead tree only to the manifold system (130, 132) from where it is routed via a test pipeline (62) to testing equipment at the host facility. Alternatively, one or more modules (132) of the manifold system (130, 132) may be replaced by one or more different modules each containing a multi-phase flow meter so that testing can take place at the manifold system.

Abstract: A bath for a disabled person, the bath having a body with a side opening which is closable by vertically displaceable door under the action of a door movement mechanism including a counter-weight beam (56) either end of which is linked to an end of the door by a chain. The weight of the counter-weight beam (56) is selected so as to bias the door towards its closed position. The beam (56) is connected by a pin (66) to over-centre lockable link arms (60, 62). When the beam approaches its lowermost position, as the door closes, a stub portion (72) of a pivot pin (64) connecting the link arms (60, 62) enters a locking fork (77) which is displaced by a motor (82) to effect over-centre locking of the link arms (60, 62) and thereby seal a channel on an inner face of the door against a lip disposed around the opening.

Abstract: A retrievable fluid separation module (2) for a seabed processing system to which flow lines are connected includes one portion (60) of a multi-ported valve isolation connector (5) and a separator chamber (6) for separating a plurality of fluids from a received fluid mixture. The separator chamber has an inlet flow line (12) for the received fluid mixture and an outlet flow line (15, 16) for each separated fluid. The flow lines are connected to the one portion of the connector (5) which selectively isolates the module from or connects it to the flow lines by means of a second complementary portion (61) of the multi-ported valve isolation connector with which the first portion is adapted to engage. There may be a modulating valve (25) in at least one outlet flow line (16) for controlling flow therethrough and a control actuator (63) for controlling the or each modulating valve.

Abstract: A two-part connector (1) is provided for use in connecting and disconnecting fluid carrying conduits. The connector comprises lower and upper parts (2, 3) each having four fluid carrying duct (15) therethrough, and a valve member (17) for each duct. Each duct in the lower part (2) is aligned with its respective duct in the upper part (3) when the two connector parts are connected together. The connector has clamps (24) for retaining the lower and upper parts (2, 3) together in sealing engagement. The clamps are mounted on the upper connector part (3) and are pivotable thereabout. Hydraulic pistons are used to move the clamps, the clamps being located in a first position pivoted away from the connector whilst the lower and upper parts (2, 3) are being aligned relative to each other.

Abstract: To install a modular seabed processing system (1) on a seabed, a monopile foundation (3) is first lowered down and driven in to the seabed. A docking unit (4) is lowered towards the installed foundation (3) so that a mating clamp system (6) mounted on the docking unit is aligned with a spigot (5) on the foundation. The clamp system then clamps the spigot to fix the docking unit onto the foundation. Flowlines (2) and an electrical power connector plug (18) are connected to the docking unit. A first retrievable substantially autonomous module (8) is lowered and connected to the docking unit (4) by a multi-bored connector (10, 11) and the plug (18) on the docking unit is engaged by a corresponding socket (17) on the module. Isolation valves (14, 16) in the docking unit and module are opened so that the module (8) is able to act on fluid received from the flowlines (2) via the multi-bored connector (10, 11).

Abstract: A rotary valve for blocking opposed apertures of a valve body includes a central assembly comprising laterally offset hemi-cylindrical first camming surfaces on an exterior of a rotatable spool and substantially hemi-cylindrical seal plates with hemi-cylindrical first cam following surfaces which engage the first camming surfaces. Stop pins fixed to the valve body run in rebates in the seal plates to limit rotation of the seal plates to 90°. Each of four clearance members is supported by a wedging block loosely located in a recess in the spool, slidingly extends through a radial slot in one of the seal plates and prevents the spool jamming the seal plate against an inner face of the valve body during closing of the valve until a projecting end of the clearance member enters a recess in the valve body.

Abstract: A valve actuator (1) is provided which comprises an actuator stem (4) extending from a housing (2) which contains a sleeve (17). The actuator stem (4) is driven so as to cause the sleeve to compress a stack of springs (22) within the housing until bolts (25) engage the sleeve, locking the springs in a compressed state. At the same time an armature (28) on the actuator stem is attracted to an electromagnet (29) within the housing. The actuator stem can then be driven to open or close a valve in a controlled manner without first compressing or releasing the springs. In an emergency, the electromagnet is switched off, releasing the armature thus unlocking the stack of springs. The released springs push the piston which partially retracts the actuator stem into the housing causing the valve to be closed.