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 pump or compressor unit (1) suited particularly for mixed phase fluids, e.g. mixed gas and oil, has a multistage axial flow compressor device with contra-rotating vanes. An upstream mixer device (10) and a downstream centrifugal impeller device (32) can each be driven by the compressor device (21, 26, 27, 29), which may be shaped to provide a flow passage of decreasing cross-section in the flow direction. The compressor drives may be supplied by axially adjacent electric motors (24, 25) which may surround rotating sleeves (21) carrying the compressor vanes. A fluid can be circulated through the unit, e.g. for electrical insulation, and may be leaked into the pump fluid through seals, when it may contain a corrosion inhibiting agent. The unit may be arranged to be movable along a pipeline under fluid pressure to engage power supply contacts at a predetermined location.

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.

Abstract: An electrically powered submersible pump system has a pipe stack in which a dielectric oil is circulated within tubular electric power supply conductors, for which the oil provides insulation, down to the pump head to cool and lubricate the motor bearings. The oil is returned between the conductors and a surrounding cofferdam pipe. The liquid being pumped is guided in a duct between the cofferdam pipe and an outer load bearing pipe. The pipe stack is divisible into sections of convenient length, the conductors, the cofferdam pipe, and the outer pipe having releasable connector means at each end of each pipe stack section.