Downhole connection assemblies include a connector to receive a conductor and pin at opposite ends. The connector includes a first electrical collet, a separate second electrical collet and a sleeve. The first collet includes a first recess in a first end to receive the conductor and a second recess in a second end to receive the pin. The second collet is positioned around the pin and separated from the first collet. The sleeve is positioned around the pin, first collet and the second collet. Downhole cables include a center electrical conductor, a first insulator positioned around the center conductor, a second insulator positioned around the first insulator, and a pressure tube surrounding the second insulator. The cable further includes one or more slots extending axially along a length of the second insulator, or one or more slots extending axially along an inner diameter of the pressure tube.

Downhole connection assemblies include a connector to receive a conductor and pin at opposite ends. The connector includes a first electrical collet, a separate second electrical collet and a sleeve. The first collet includes a first recess in a first end to receive the conductor and a second recess in a second end to receive the pin. The second collet is positioned around the pin and separated from the first collet. The sleeve is positioned around the pin, first collet and the second collet. Downhole cables include a center electrical conductor, a first insulator positioned around the center conductor, a second insulator positioned around the first insulator, and a pressure tube surrounding the second insulator. The cable further includes one or more slots extending axially along a length of the second insulator, or one or more slots extending axially along an inner diameter of the pressure tube.

Downhole connection assemblies include a connector to receive a conductor and pin at opposite ends. The connector includes a first electrical collet, a separate second electrical collet and a sleeve. The first collet includes a first recess in a first end to receive the conductor and a second recess in a second end to receive the pin. The second collet is positioned around the pin and separated from the first collet. The sleeve is positioned around the pin, first collet and the second collet. Downhole cables include a center electrical conductor, a first insulator positioned around the center conductor, a second insulator positioned around the first insulator, and a pressure tube surrounding the second insulator. The cable further includes one or more slots extending axially along a length of the second insulator, or one or more slots extending axially along an inner diameter of the pressure tube.

A downhole cable includes a central core. The central core includes a metal tube having a plurality of optical fibers therein or a copper wire. The downhole cable further includes an extruded aluminum tube surrounding the central core.

The invention relates to the skin-effect based induction-resistive heating units and can be used in devices intended for prevention of paraffin-hydrate deposits formation in oil-and-gas wells and pipelines, as well as for warming up of viscous products in pipelines and vessels for the purpose of their transporting and pumping. The skin-effect based heating cable contains the center conductor, the inner insulation layer and the ferromagnetic outer conductor coaxially located around them. The invention enables to simplify using due to increase of the heating cable flexibility and due to reduce the energy consumption at its operation.

The invention relates to the skin-effect based induction-resistive heating units and can be used in devices intended for prevention of paraffin-hydrate deposits formation in oil-and-gas wells and pipelines, as well as for warming up of viscous products in pipelines and vessels for the purpose of their transporting and pumping. The skin-effect based heating cable contains the center conductor, the inner insulation layer and the ferromagnetic outer conductor coaxially located around them. The invention enables to simplify using due to increase of the heating cable flexibility and due to reduce the energy consumption at its operation.

Process for manufacturing a power cable includes: providing a power cable core having an electric conductor; providing a copper foil; providing a protective strip over the power cable core, the protective strip having a radially inner and outer surface and being made of copper with a coating; folding the copper foil around the power cable core so as to bring two longitudinal copper foil rims to contact one to the other; welding the two contacted longitudinal copper foil rims thus obtaining a copper sheath in form of a tube with a welding seam; reducing the diameter of the copper sheath to put it into direct contact with the power cable core and the protective strip; heating the protective strip and the copper sheath at a temperature higher than the melting temperature of the coating of the strip so that the coating fuses in the welding seam.

Process for manufacturing a power cable includes: providing a power cable core having an electric conductor; providing a copper foil; providing a protective strip over the power cable core, the protective strip having a radially inner and outer surface and being made of copper with a coating; folding the copper foil around the power cable core so as to bring two longitudinal copper foil rims to contact one to the other; welding the two contacted longitudinal copper foil rims thus obtaining a copper sheath in form of a tube with a welding seam; reducing the diameter of the copper sheath to put it into direct contact with the power cable core and the protective strip; heating the protective strip and the copper sheath at a temperature higher than the melting temperature of the coating of the strip so that the coating fuses in the welding seam.

A shielded conductive path, including: a cylindrical shielding pipe that is in a state in which two semi-cylindrical members made of a metal material are joined together, and that is provided with a bend at a portion located in an axial direction; an electrical wire housed in the shielding pipe; a first weld that is provided only in a partial region of the shielding pipe that includes at least the bend in the axial direction, the first weld liquid-tightly joining the two semi-cylindrical members; and a second weld that is provided in all regions of the shielding pipe other than the first weld in the axial direction, the second weld liquid-tightly joining the two semi-cylindrical members, wherein a joining range of the second weld in a radial direction is narrower than a joining range of the first weld in the radial direction.

A shielded conductive path, including: a cylindrical shielding pipe that is in a state in which two semi-cylindrical members made of a metal material are joined together, and that is provided with a bend at a portion located in an axial direction; an electrical wire housed in the shielding pipe; a first weld that is provided only in a partial region of the shielding pipe that includes at least the bend in the axial direction, the first weld liquid-tightly joining the two semi-cylindrical members; and a second weld that is provided in all regions of the shielding pipe other than the first weld in the axial direction, the second weld liquid-tightly joining the two semi-cylindrical members, wherein a joining range of the second weld in a radial direction is narrower than a joining range of the first weld in the radial direction.