RU2302679C1 - Electric cable for feeding submersible oil pumps - Google Patents

Abstract

FIELD: electrical engineering; cables for feeding underground equipment of oil wells such as submersible oil pump motors and other pieces of equipment.

SUBSTANCE: novelty is that proposed electric cable has at least two parallel polymeric material insulated current-carrying conductors, each conductor being also covered with metal band sheath coated on two sides with crosswise corrugated polymeric material longitudinally placed on insulation with its edges overlapping; conductors covered with mentioned sheath have common external armor of spirally arranged metal bands. Mentioned sheath provided with longitudinally disposed corrugated metal band having integral polymeric weld provides for desired tightness of insulation and for its reliable protection. Compared with prior art, proposed cable is characterized in its suitability for use in oil wells in direct contact with well liquids.

EFFECT: enhanced resistance to environmental impacts, enlarged service life of cable.

1 cl, 4 dwg

Description

The electric cable for powering the electric motors of submersible oil pumps refers to the underground equipment of oil wells and can be used to power the electric motors of submersible oil pumps.

Known electrical cable for submersible oil pumps, containing conductive cores coated with heat-resistant insulation, and on top of the insulation with a barrier element, and covering all cores common armor made of galvanized steel tape, located on a cushion of non-woven fabric, characterized in that it additionally contains a filler, located in the interface between the cable and the ground wire mounted longitudinally on top of each barrier element, as well as a braid of synthetic threads, tightly covering the ground a cleaning wire together with a barrier element, the barrier element being made of a composite two-layer metal foil with a polyethylene sublayer and laid with a polyethylene sublayer directly on the insulation (Utility model of the Russian Federation No. 22265. Declared September 14, 2001, No. 2001125253/18. Published: March 10, 2002 )

Such a technical solution to the cable design slows down the process of penetration of the well fluid into the insulation of the cable, but does not prevent it due to the fact that the barrier element is not a solid sheath impermeable to the well fluid.

The closest analogue in technical essence is the "Electric cable" according to patent RU 2206135, IPC 7 Н01В 7/12 from 01.06. 2001, publ. 06/10/2003.

The invention relates to electrical engineering, in particular to the design of electrical cables designed to power submersible borehole electric pumps and other devices.

The objective of the invention is to provide a cable that is resistant to environmental influences. The technical result is achieved in that the electric cable contains at least two parallel conductive conductors with insulation made of a polymer material, each of which is coated with a sheath made of a metal tape with a double-sided polymer coating, laid on top of the insulation longitudinally with overlapping edges, and having transverse corrugation, and a layer of polymer material located on top of the tape, while the cores covered by the specified sheath have a common outer armor of spirally imposed me thallic ribbons. The presence of a shell containing a longitudinally arranged corrugated metal tape with a hollow welded polymer seam allows for tightness and insulation protection.

Corrugation allows you to fix the edges of the tape relative to each other in the longitudinal direction, which also improves the integrity of the seam under longitudinal loads.

The use of transverse corrugation in this case is not aimed at increasing the flexibility of a particular element in the longitudinal direction, which is a well-known property, but at achieving a new, previously unknown technical result - increasing the tightness of the shell by ensuring the integrity of the weld.

For additional fixation of the edges of longitudinally arranged corrugated tapes, the cable insulation can be made of elastomer or thermoplastic elastomer, i.e. from materials with highly elastic properties, which allows for fixing the lower sections of the corrugations by pressing them into the insulation material, as well as in addition to radial, to ensure longitudinal tightness.

Such a technical solution to the cable design prevents the penetration of the borehole fluid into the cable insulation, but with alternating current in the shells of metal tapes that each core has, losses will occur that will heat up the cable and damage it (Fundamentals of cable technology / V.A. Privezentsev, I.I. Grodnev, S. D. Kholodny, I. B. Ryazanov / Edited by V. A. Privezentsev. M.: Energy, 1975. 472 p.)

Pressing the lower sections of the corrugations into the insulation unevenly thin the insulation and can lead to breakdown of the insulation when the cable bends during lowering or lifting.

The objective of the proposed technical solution is to create a cable with increased, relative to analogues, service life, suitable for work in oil wells, under the conditions of direct impact of the well fluid on the electric cable.

The problem is solved due to the fact that the electric cable for powering the electric motors of submersible oil pumps consists of parallel conductive conductors insulated with polymer material, on top of which there is an additional sealed metal non-magnetic flexible sheath with transverse corrugations made on it, while the corrugations are made with bulges directed from the core and located at intervals along the length of the cable, while the gaps between the corrugations are made equal to or greater than size corrugation ceiling elements, wherein the corrugations are arranged one against the shell core shell adjacent gaps.

The use of an additional sealed metal non-magnetic flexible shell with corrugations made on it, and their location with a gap along the length of the cable, which ensures longitudinal tightness, allows single-layer insulation, since it reliably seals the core insulation, and thus protects it from penetration of the well fluid, while maintaining proper cable flexibility.

The implementation of the corrugations with bulges directed from the core excludes the pressure of the corrugations on the insulation of the core, its thinning and breakdown.

The choice of the size of the gaps between the corrugations equal to or greater than the longitudinal size of the corrugation, when the corrugations of one shell are placed against the gaps of the shell of the adjacent conductor and the corrugations of one conductor enter between the corrugations of the neighboring conductor, allows cables of different flexibility and dimensions to be made.

The use of non-magnetic metal avoids inducing currents in the protective sheath and cable failure.

The drawings show an electric cable with different gaps L ₂ between the corrugations. Figure 1 shows an electric cable, the gaps between the corrugations L ₂ which are equal to the longitudinal size L ₁ corrugation. Figure 2 shows the electric cable, the gaps between the corrugations L ₂ which is larger than the longitudinal size L ₁ corrugation.

In figure 1, 2 tape armor 1, pillow 2, corrugated shell 3, insulation 4, conductive core 5, corrugations 6, the gaps between the corrugations 7, the longitudinal dimension L ₁ corrugation, the longitudinal dimension L ₂ gap.

The electric cable is made as follows.

The electric cable consists of conductive conductors 5 arranged in parallel (Figs. 1-3) insulated with polymer material 4, on top of which there is an additional sealed metal non-magnetic flexible sheath 3, with corrugations 6 made on it with a longitudinal dimension L ₁ with bulges directed from cores and spaced 7 with a longitudinal dimension of L ₂ along the length of the cable. The gaps 7 with a longitudinal size L ₂ between the corrugations are made either equal to or greater than the longitudinal size L _{1 of the} corrugation, while the corrugations 6 of one shell are placed against the gaps 7 of the shell of the adjacent core. The electric cable has a common armor 1. The shell 3 is separated from the armor 1 by a pillow of non-woven fabric 2.

When the gap 7 between the corrugations L ₂ equal to (figure 1) or greater (figure 2) the longitudinal size L ₁ corrugation 6, the electric cable has a smaller width than the prototype, since the corrugations of one core tightly or with a gap between the corrugations of the adjacent core therefore, it is advantageous to operate them in wells with a small diameter tubing.

When the gap 7 between the corrugations L ₂ is larger than the longitudinal size L _{1 of the} corrugation 6 (Fig.2), the electric cable has more flexibility than with the gap with equal dimensions.

The set of features is new and leads to a technical result, which consists in creating a cable with an increased, relative to analogues, service life suitable for working in oil wells, under the conditions of direct impact of the well fluid on the electric cable.

Claims (1)

An electric cable for powering the electric motors of submersible oil pumps, consisting of parallel conductive conductors insulated with polymer material, on top of which there is an additional sealed metal non-magnetic flexible sheath with transverse corrugations made on it, characterized in that the corrugations are made with bulges directed from the core and located with gaps along the length of the cable, while the gaps between the corrugations are made equal to or greater than the longitudinal size of the corrugation, at m corrugations against one shell has gaps adjacent conductor casing.

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