EP0208178A1 - Supply cable for oil drill probes - Google Patents

Abstract

Cable consisting of a central electrical conductor (10) and two lateral bearer-cables (20), the conductor and the two bearer-cables being embedded in a flattened elastomeric cladding (30), characterised in that the electrical conductor (10) is composed of an electrical wire (11), an inorganic insulating layer (12) and an external cladding (13), and in that the elastomeric cladding is covered with a flexible metallic exterior armour (40). Application to oil drilling. <IMAGE>

Description

The present invention relates to a probe supply cable for oil drilling.

This type of cable should be as small as possible to facilitate its passage through the borehole and allow winding long lengths on drums. In addition, this type of cable must resist the combined action of three extremely severe constraints; a mechanical stress because the pressure can reach a value greater than or equal to 350 bars, a chemical stress which is a function of the nature of the petroleum effluent, and finally a thermal stress because the temperature can reach a value greater than or equal to 150 ° vs.

We know, in particular from document GB-A-2 027 553, a cable for oil drilling comprising a central electrical conductor and two lateral carrying cables, these three elements being embedded in a flat elastomer sheath. This cable does indeed ensure a minimum bulk thanks to the flat shape of the elastomer sheath, also provides good resistance to crushing thanks to the presence of two lateral carrying cables, but on the other hand, neither provides good effective external protection against clashes or other accidents of this kind, and neither good protection against the high temperatures reached at the bottom of a borehole.

The object of the present invention is to provide effective external protection by covering the elastomer sheath with an external metallic armor, as well as very good resistance to high temperatures by using a mineral insulating cable as the central conducting cable.

The subject of the present invention is a probe supply cable for oil drilling, consisting of a central electrical conductor and two lateral carrier cables, the conductor and the two carrier cables being embedded in a flat elastomer sheath, characterized in that the electrical conductor is composed of an electric wire, a mineral insulating layer and an external sheath, and in that the elastomer sheath is covered with a flexible metallic outer armor.

• La figure 1 montre le câble muni de tous ses éléments.
• La figure 2 montre le câble, en coupe selon II de la figure 1.

A cable according to the invention is described below, by way of example and with reference to the accompanying drawings.

• Figure 1 shows the cable with all of its components.
• FIG. 2 shows the cable, in section along II of FIG. 1.

In FIG. 1, we see the central conductor 10 made up of a central wire 11 made of copper, a mineral insulator 12 made of magnesia and a sheath 13 made of stainless steel, the two carriers 20 each made up of steel wires twisted, the synthetic elastomer sheath 30 coating the central conductor and the two carrier cables, and finally the external metallic armor 40 of the "Interlock" type.

This outer armor 40 consists of a single metal strip 41 wound helically and the two edges of which overlap.

The two carrier cables 20 are wired in the opposite direction to obtain an anti-gyratory effect and to prevent kinking of the cable.

Figure 2 clearly shows the flat shape of the cable and the outside diameter of the carrier cables, greater than that of the central conductor, to ensure their function, anti-crushing.

Claims (3)

1 / Probe supply cable for oil drilling, consisting of a central electrical conductor (10) and two lateral carrier cables (20), the conductor and the two carrier cables being embedded in an elastomer sheath (30) flat, characterized in that the electrical conductor (10) is composed of an electric wire (11), a mineral insulating layer (12) and an external sheath (13), and in that the elastomer sheath. 'is covered with a flexible metallic outer armor (40). 2 / cable according to claim 1, characterized in that the outer armor (40) consists of a single metal strip (41) wound helically. 3 / Cable according to one of claims 1 or 2, characterized in that the two carrier cables (20) are wired in the opposite direction.

Images