Abstract: A centrifugal separator comprises a drum (1) rotatable about its axis within which annular walls (10, 20) define discharge chambers (11, 21) at the ends of the drum, from which separated fluids of different specific gravities are discharged by respective scoops (14, 24). Alternatively, annular walls (44, 45 and 47, 49) define both such chambers at one end only of the drum. The dimensions of the annular walls are chosen so that the separator is self-regulating, in that the separated fluids are discharged independently of the proportions of the fluids in the incoming mixture, so that operation of the separator does not have to be controlled in response to sensing of the separation process within the drum.

Abstract: An apparatus for the treatment of a multiphase fluid, comprising a rotatable shaft having a fluid flow path coaxial with the shaft. A fixed guide member surrounds the shaft and comprises annular plural helical channels for imparting centrifugal forces to the fluid to concentrate heavier fluid into an outer annular flow path around an inner flow path for lighter fluid. An impeller is supported on and driven by the shaft. The flow in the outer flow path is diverted, so as to divert the flow of the fluid of greater specific gravity into an annular channel member having an impeller. A stationary scoop extracts fluid from the channel member. The impeller comprises generally radially outwardly extending disks receiving fluid flowing on the inner flow path between them. Guide vanes are carried by the disks for guiding the fluid radially outwardly. A discharge chamber in the form of a volute is provided for the lighter fluid on the inner flow path issuing from between the disks.

Abstract: Apparatus for the treatment of a multiphase fluid, comprises a pretreatment stage (60) upstream of a treatment stage, the pretreatment stage being arranged to cause an incoming flow of multiphase fluid to concentrate fluids of greater and lesser specific gravity into respective flow paths for subsequent treatment in the treatment stage and the pretreatment stage comprising a cyclonic separator device (60) concentrating fluid or fluids of greater specific gravity into an outer annular flow path around an inner flow path for fluid or fluids of lesser specific gravity. The treatment stage comprises a centrifuge having a separator drum (65) rotatable about the axis (66) thereof with an inlet end portion next to the cyclonic separator device (60) comprising concentric inner and outer walls (76, 70) and helical vanes (75) between the walls.

Abstract: A metering device for multiphase fluid, for example, crude oil, comprises a .gamma. or X-ray densitometer incorporating windows for the metering radiation of boron carbide. The boron carbide windows can be provided by a sleeve guiding the fluid flow, the sleeve (51) being reinforced by a thin external layer (52) of carbon fiber embedded in epoxy resin. Alternatively, a steel tube (26) receiving the fluid flow has aligned transverse apertures (47) containing plugs (49) of boron carbide.

Abstract: A well completion system comprises production tubing (5) extending downhole from wellhead equipment (2) to a plurality of completion systems (7, 8, 9). A well testing facility comprising a test loop (26) with flow metering equipement (27) is included in the wellhead equipment. Each of a plurality of independently adjustable flow control means (57) is operable to stop the flow of fluid from a respective one of the completion assemblies into the production tubing. The downhole completion assemblies (7, 8, 9) are mounted on a common fluid and electrical supply means (4) comprising tubular electrical conductor means (42) and tubing (41, 45, 46) defining fluid paths.

Abstract: A pump or compressor module for undersea use has a housing having a pump or compressor unit received therein. The pump or compressor unit has first and second impeller assemblies. The first and second impeller assemblies are driven in opposed directions about a common axis. The drive has first and second electric motors having respective drive shafts drivingly connected to the first and second impeller assemblies respectively. First and second motor casings contain the first and second motors respectively, the motor casings being within the housing. There is a seal compartment in each of the motor casings and a drive shaft seal within each of seal compartments. Barrier fluid is supplied to each of the seal compartments at a higher pressure than to the rest of the motor casing.

Abstract: A pumping apparatus has a linear electric motor (10; 40) reciprocally driving motor pistons (16; 45) hydraulically coupled with pump pistons (25) or with coupling pistons (51) mechanically connected with pump pistons (61) which move the fluid to be pumped. For undersea use, the coupling arrangements allow convenient separation and retrieval of subassemblies requiring relatively frequent servicing.

Abstract: A pipe system comprises a plurality of pipe members (2), mechanical connections at the end regions of the pipe members whereby the pipe members can be connected together into end-to-end relationship to provide at least one fluid flow path along them, and electrical conductors (10; 110) carried by the pipe members, the electrical conductors having contact areas (19) exposed at the end regions of the pipe members so that electrical connection between the conductors of adjacent pipe members can be effected by bridging members (25) spanning the end regions of the pipe members.

Abstract: A module is loaded on a submerged installation to interface an umbilical termination head with a pump module by way of vertically and horizontally directed connection units (21, 26) carried by the module and from which connection members are projected into respective receptacles (70). The units and the receptacles are mounted so as to be readily alignable to ball-and-socket joints (46) or universal couplings (74). The connection members can be projected in a first stage to effect alignment and in a subsequent stage to effect hydraulic and/or electrical connection. The mounting of the units and receptacle is such as to permit retrieval of the module in the event of a failure to withdraw the connection members back into the units.

Abstract: Material is thermally extracted from an underground formation with the aid of heat supplied by electrical resistance heaters (21) or by tubing (5, 6) serving as such, or by heated fluid conveyed downhole in pipes (12), which may serve as electrical conductors, or as resistance heaters, or which may be heated downhole. The fluid may be circulated upwardly after passage through a downhole pump unit where the fluid is suitable.

Abstract: In a subsea fluid extraction system, the wellhead equipment comprises an X-mas tree on a guide base, the tree having a borethrough which can be run and retrieved a pump unit including an electric motor driving an impeller, the pump unit being suspended from a pump hanger in the X-mas tree by an elongate electrical conductor assembly consisting of concentric tubular conductors with insulating sleeves therebetween. An outer tube spaced around the conductors provides a fluid passage communicating through the pump unit with a second passage within the conductors for circulation of barrier fluid. Electrical supply to the pump unit is effected by a female connector located at the side of the X-mas tree which mates with an upright connector element on a transformer on the guide base.

Abstract: Apparatus for coupling a subsea module to an umbilical termination head from a subsea installation which comprises a receiver (14) mounted on the module, a receiver (15) mounted on the umbilical, and a conductive insert coupling (CIC) (13). The receivers (13, 14) each have electrical terminal sets (24, 25). The CIC (13) has a pair of spaced electrical terminal sets (22, 23) in which respective terminals in each set are electrically connected by concentric conductive tubes. The receivers (14, 15) are arranged to receive the CIC (13) so that when it is in position in the receivers (14, 15), each of the CIC terminal sets (22, 23) contacts one of the receiver terminal sets (24, 25) thereby forming an electrical connection between the two receiver terminal sets (24, 25).

Abstract: A liquid is supplied to a vessel (10) to form a pool (21) from which it discharges through a venturi. A supply pipe or pipes (12, 30) convey other liquids and/or gases from separate sources or from above the liquid pool into the venturi for mixing with the liquid. The supply pipes can extend through the pool and be perforated (22) to tend to maintain the level of the pool. Associated with the venturi are pressure sensors (40, 41) for measuring flow and a densiometer (52) permitting mass flow rate measurement of gas and liquid phases. The apparatus can be incorporated in a cartridge (60) for reception in a receptacle (61) at a subsea installation.

Abstract: A pump unit comprises a pump piston driven by a linear electric motor having induction and reaction members with closely adjacent flat surfaces. A reaction member can be sandwiched between two induction members. Co-operating induction and reaction members extend radially from a rod connected to the piston or to two axially spaced pistons or are grouped tangentially around it. The piston or pistons are driven synchronously and so that constant force is applied by way of a control system which includes a trajectory generator and a controller responsive to selected inputs relating to pump performance characteristics and feedback signals derived from measured current flow and piston position.

Abstract: An electric motor suitable for incorporation in pipestacks for drilling and pumping applications has a drive shaft (4) carrying spaced rotor discs (6) driven by annular stator windings (7) carried by the motor housing wall. The windings (7) are organized as linear motors operating on a circular path and provision can be made for energization of the windings so as to cause axial movement of the shaft, for hammering or braking action. The shaft (4) can be tubular to provide a passage for drilling mud, or for a fluid being pumped.

Abstract: A drilling system comprises a drill string (1) incorporating inbuilt tubular conductors (25), a mud supply passage, and passages for protective or other fluids. The drill string can be advanced by selectively actuable pistons (51,60) exposed to drilling mud flow, by electrically driven traction units (71,74) engaging the drill hole wall or by a linear electric motor element (82) co-operating with a drill hole casing (24), which can be moved thereby relative to the drill string. The drill bit (106) of the drill unit is driven rotatably by an electric motor (111,112) or reciprocably by a linear electric motor (125). The drill unit can be of two relatively slidable parts, with fluid pressure, which may be generated within the unit (189) axially loading the drill bit. Drilling forms can be resisted by clamps (129) clamping the unit and/or the drill string to the drill hole wall. The drilling direction can be adjusted by use of these clamps.

Abstract: A non-homogenous mixture of liquid and gas is fed into a vessel to form a body of gas above a pool of liquid. Liquid is fed from the pool through a discharge pipe containing a constriction forming a venturi and gas is drawn from the gas body through a pipe extending through the liquid pool into the discharge pipe to effect mixing of the liquid and the gas in the venturi. Perforations in the discharge pipe adjust the amounts of gas and liquid leaving the vessel to maintain both liquid and gas within the vessel.

Abstract: A pipe assembly for use in production or drilling systems comprises a plurality of pipe members connected together in end-to-end relationship and a plurality of tubular conductor members electrically connected together in end-to-end relationship. The members have co-operating tapered or stepped portions, and/or screw-threaded portions whereby the pipe members support the conductor members in internal or external coaxial relationship. A logging unit can be moved along the assembly unit under fluid pressure to engage stop means for connecting the unit with the conductor members, or a logging unit can be incorporated in a pipe member wall. An outer pipe can surround the pipe assembly to provide with the pipe assembly interior two passages for the reception, flow or circulation of fluids, for example extracted oil and/or gas and barrier fluid.

Abstract: FIG. 1 shows a sealing arrangement which includes a mushroom-shaped piston is driven to reciprocate in a cylinder by an annular driving part extending around its stem. The driving part forms the "rotor" of a linear electric motor, the "stator" of which is provided by the cylinder. The ends of the piston are exposed to respective greater and lesser pressures. During movement of the driving member relative to the piston against the bias of a spring, fluid flow through a passage containing a one-way valve generates an overpressure in a chamber to which a seal between the piston head and the cylinder is exposed and thus prevents leakage of fluid around the seal. FIG. 2 shows a modification in which the piston has a central well containing a plunger biassed by a diaphragm. Here the overpressure is generated in the well and a passage exposes a seal to the overpressure to prevent leakage around the piston.

Abstract: A submersible pump system comprises a lowermost electrically driven pump unit (4,55) providing an inlet to the system for liquid to be pumped and one or more like pumps (5,55) positioned above it and connected in series. Electric power is supplied to the units by way of conductors within a central pipe (14) concentric with an outer cofferdam pipe (12), dielectric oil being circulated through the conductor pipe and between it and the cofferdam pipe and thus through the pump unit motors which have hollow drive shafts (21) around the conductor pipe. The pump stack may be located within a well casing (52), by sealing rings (62) expanded by the dielectric oil pressure, or surrounded by an outer load-bearing pipe (10). The liquid pumped flows externally of the pump stack and the system can be constructed in separate lengths which can be readily assembled on installation.