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 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 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 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.