Abstract: A stator has a field winding, the winding comprising a plurality of axial conductors connected at their ends to form at least one circuit with a number of turns. Each axial conductor is disposed within a tubular axial insulation member, the tubular axial insulation members being disposed within a stack of laminations. The axial conductors and the tubular insulation members are radially distributed at equal angles. The position of the axial conductors and the tubular insulation members is predetermined.

Abstract: A stator has a field winding, the winding comprising a plurality of axial conductors connected at their ends to form at least one circuit with a number of turns. Each axial conductor, or set of axial conductors having a common voltage, is disposed within an insulated channel member, the insulated channel member being disposed within a stack of laminations. The axial conductors and the tubular insulation members are radially distributed at equal angles.

Abstract: A rotor system for a downhole motor comprises a set of permanent magnets, a set of conductors and a pair of end conductor rings connecting the set of conductors. The set of permanent magnets and the set of conductors being substantially coaxial and having the substantially the same linear extent.

Abstract: A rotor system for a downhole motor comprises at least one permanent magnet rotor section, and at least one squirrel cage rotor section. The permanent magnet rotor section and the squirrel cage rotor section are joined in series by a connection. Ideally, the connection comprises a male self lock taper on one rotor, and a corresponding female self lock taper on the other rotor.

Abstract: A downhole electric submersible pump, comprises at least one pump unit having a pump inlet, and an electric motor system to power the pump, the electric motor system comprising an induction motor and permanent magnet motor. The induction motor and permanent magnet motor share a common power supply, connected in series.

Abstract: A downhole electrical wet connector comprising a plug which is slidingly inserted into a socket, the socket comprising a series of wiper seals spaced apart by separation zones, each zone being individually supplied with dielectric fluid from a separate reservoir. A retractable insert is arranged in the socket and displaced by the plug during connection. The fluid pressure in each zone is individually regulated relative to ambient wellbore pressure and the pressure in adjacent zones and optionally equalized to minimize loss of fluid.

Abstract: A wet connection system comprises a fixed tubing with an orientation profile and redundant, first and second fixed wet connectors, and an electrical submersible pump assembly (ESP) comprising a wet connector and an orientation element for engaging the orientation profile. The ESP can be reconfigured, for example, by interchanging its component modules so as to change the position of its wet connector with respect to the orientation element, whereby the wet connector on the ESP can be engaged alternatively with either one of the fixed wet connectors when the orientation element is engaged with the orientation profile in the same deployed position of the ESP.

Abstract: A motor transmission and gearbox are disclosed for downhole use, which include a first motor driving a first input shaft, a second motor driving a second input shaft, and a gearbox comprising at least a ring gear, a sun gear, and a planetary gear and planetary carrier. The first input shaft driving either the ring gear, the sun gear or the planetary gear and/or planetary carrier, the second input shaft driving one of the gears not driven by the first input shaft, and the remaining gear driving the output shaft.

Abstract: A flow restrictor for controlling the flow of cement or other fluid in oil wells comprises a plurality of restrictor elements, each defining first and second apertures, which are assembled in a stacked configuration and slidingly inserted into the well casing or other tubing so that the first apertures define a direct flowpath, preferably including a non-return valve, and the second apertures define a second, indirect flowpath between the elements and the inner surface of the tubing. The elements include seals for fluidly sealing each element in the bore of the tubing which are preferably slidably retractable and resiliently radially outwardly biased so as to adapt conformably to different tubing types having different internal diameters. The restrictor may slide along the tubing in use.

Abstract: A synchronous permanent magnet motor is controlled independently of position sensing means by determining the system parameters including the motor impedance and back-emf and the cable impedance and supplying power according to a predefined voltage:frequency ratio which is determined based on said system parameters to provide a desired rate of acceleration determined by the supply voltage.

Abstract: A synchronous permanent magnet motor is controlled independently of position sensing means by determining the system parameters including the motor impedance and back-emf and the cable impedance and supplying power according to a predefined voltage:frequency ratio which is determined based on said system parameters to provide a desired rate of acceleration determined by the supply voltage.

Abstract: A downhole electrical wet connector comprising a plug which is slidingly inserted into a socket, the socket comprising a series of wiper seals spaced apart by separation zones, each zone being individually supplied with dielectric fluid from a separate reservoir. A retractable insert is arranged in the socket and displaced by the plug during connection. The fluid pressure in each zone is individually regulated relative to ambient wellbore pressure and the pressure in adjacent zones and optionally equalised to minimise loss of fluid.

Abstract: An electric submersible pump assembly (ESP) (21, 120) is deployed in a production tube (20, 100) in a borehole such that the motor (26, 41, 121) of the ESP is spaced from the inner wall of the production tube, defining a conduit (36, 111) through which the pumped well fluid can flow to cool the motor. The production tube may have an enlarged diameter portion (25, 76, 101) within which the motor is positioned. Alternatively or additionally, the ESP and/or the production tube may be provided with stabilizing spacers (24, 45, 140, 141) which extend between the ESP and the tube to centralize the ESP in the tube and support it against vibrational movement, the spacers defining an annular conduit (36, 111) between the motor casing and the production tube.

Abstract: According to the present invention, there is provided a well pumping system comprising a length of coiled tubing extending to the surface of the well, a first electric pump, a first electric motor, and a sealing means that seals against the side of the well. The sealing means include a first fluid path through which coiled tubing is in fluid communication with the well beneath the sealing means, and a second fluid path through which first electric pump is in fluid communication with the well beneath the sealing means.

Abstract: A cable and tubing suspends an electrically powered tool in a borehole and provides the tool with electrical power. The cable is disposed in the tubing, and the cable incorporates a conducting member which carries the majority of the tensile stress on the cable without the cable being secured along its length to the inside of the tubing. The cable may be capable of supplying high voltage electrical power, in which case the cable comprises a conducting member having a steel core, an outer cladding of copper, and at least one insulating layer surrounding the outer cladding of copper. The copper makes up between 20% and 40% of the total metal content of the cable, the cable being able to support at least its own weight.

Abstract: The present invention provides a seed blend comprising pesticidal seed and refuge seed, wherein plants grown from said pesticidal seed type do not pollinate plants grown from said refuge seed type when the seed blend is planted. In some embodiments, the refuge crop reproductively matures at a different time relative to the time at which the pesticidal crop reproductively matures. Methods for deploying the seed blend and for reducing cross-pollination between plants grown from the pesticidal seed and refuge seed are also provided.

Abstract: A wet connection system suitable for use in hydrocarbon wells preferably comprises one or more elongate, small diameter conduits (50) which extend down the wellbore (2) and terminate adjacent a locating structure (11) on the production tubing (10). Equipment (70) deployed at the locating structure is connected to one or more self supporting conductors (30) which extend down the conduits from the wellhead (5). Preferably the conductors are retractable and the conduits are sealingly connected to the equipment, allowing the equipment and conductors to be deployed and recovered independently of each other and to be flushed with dielectric oil (99) pumped down the conduits after re-connection.

Abstract: A system for installing a powered device in a downhole tube, comprising a power line disposed along a production tube and terminating in a first power connector and an orientation profile disposed in the vicinity of the first power connector. An assembly includes a powered device having a second power connector and an extending orientation capable of radial outward movement from the assembly. The powered device being lowered down the production tube, causing the extending orientation to be urged radially outwards to engage with the orientation profile and orient the device, so that the first power connector and second power connector engage to connect the powered device to the power line in an automatic manner.

Abstract: A wet connection system suitable for use in hydrocarbon wells preferably comprises one or more elongate, small diameter conduits (50) which extend down the wellbore (2) and terminate adjacent a locating structure (11) on the production tubing (10). Equipment (70) deployed at the locating structure is connected to one or more self supporting conductors (30) which extend down the conduits from the wellhead (5). Preferably the conductors are retractable and the conduits are sealingly connected to the equipment, allowing the equipment and conductors to be deployed and recovered independently of each other and to be flushed with dielectric oil (99) pumped down the conduits after re-connection.

Abstract: A downhole electrical wet connector comprising a plug which is slidingly inserted into a socket, the socket comprising a series of wiper seals spaced apart by separation zones, each zone being individually supplied with dielectric fluid from a separate reservoir. A retractable insert is arranged in the socket and displaced by the plug during connection. The fluid pressure in each zone is individually regulated relative to ambient wellbore pressure and the pressure in adjacent zones and optionally equalised to minimise loss of fluid.