OA18400A - Method of connecting cables of a unitary section of pipe intended to be assembled vertically on an underwater pipe for transporting fluids - Google Patents

Abstract

The invention relates to a method for connecting cables of a unitary pipe section intended to be assembled vertically on an underwater fluid transport pipe, comprising positioning around a lower end of the unitary pipe section (40) a female annular connector (2) to which are connected cables (14) extending along said unitary pipe section, positioning around a high end of the pipe (42) a male annular connector (24) to which are connected cables (32) extending along said pipe, and connecting the male and female connectors by sliding them vertically towards each other when assembling the unitary pipe section on the pipe.

Description

Title of the invention Method of connecting cables of a unitary section of pipe intended to be assembled vertically on an underwater pipe for transporting fluids

Background of the invention

The present invention relates to the general field of fluid transport conduits, in particular to underwater conduits, resting on the seabed or providing the bottom-surface connection for the transfer of hydrocarbons, for example oil and gas, from subsea production wells.

It relates to all types of conduits, in particular coaxial conduits of the “Pipe In Pipe” or PIP type, that is to say “conduit in a conduit”, in which an internal tube transports the fluids and an external tube coaxial with the pipe. above, also called “external envelope”, is in contact with the ambient medium, that is to say with water.

Generally, these coaxial conduits are assembled on land in units of unit length (one speaks of double, triple or quadruple joints, hereinafter indifferently referred to as "quad-joints" for quadruple sections of tube), of the order of 10 to 100m depending on the load bearing capacity of the laying system. These quad-joints are then transported to sea on a laying vessel.

During installation, the quad-joints are connected to each other on board the vessel and as they are laid at sea. The installation can be carried out via a J-shaped laying tower positioned on the laying vessel. With the J-laying, the submarine pipe is typically lowered from the laying vessel practically vertical (between + 30 ° and -10 ° with respect to the vertical). The J-laying is a simple catenary laying in which the almost vertical inclination of the pipe decreases as it moves downwards until it follows the slope of the seabed.

This J-laying method requires moving each new quad-joint from a horizontal position (along the deck of the laying vessel) to a vertical position to line up with the J-laying tower. The quad-joint is kept vertical on the laying tower to allow its lower end to be welded to the upper end of the pipe. Once the quad-joint was welded to the pipe, the latter was lowered into the sea by moving the laying vessel forward by an advance corresponding to the length of the quad-joint.

Furthermore, it is known practice to position cables in the annular space between the two tubes of these coaxial underwater conduits by making them run along the internal tube over their entire length. These cables are in particular electric cables wound around the internal tubes of the conduits to heat them by the Joule effect. This technique, called "heat tracing" (or "heat tracing" in English), keeps the fluids transported in the underwater pipes at a temperature above a critical threshold throughout their path from the production well to surface installation (and thus avoid the appearance of disturbing phenomena in the pipes in order to maintain good traffic conditions).

However, when laying a new quad-joint in J on the underwater pipe, the problem arises of the connection between the cables of the pipe and those of the new quad-joint. Taking into account the vertical position of the tubes during this installation, it is in particular necessary to ensure a connection of the cables which is simple, fast and efficient.

Purpose and summary of the invention

The main object of the present invention is therefore to provide a simple, rapid and efficient connection method.

According to the invention, this object is achieved by means of a method of connecting cables of a unitary section of pipe intended to be assembled vertically on an underwater pipe for transporting fluids, comprising:

positioning around a low end of the unitary section of pipe a female ring connector to which are connected cables extending along said unitary section of pipe;

positioning around an upper end of the pipe of a male annular connector to which are connected cables extending along said pipe; and connecting the male and female connectors by sliding them vertically towards each other when assembling the unitary section of pipe to the pipe.

The use of male and female connectors to which the cables of the single pipe section and those of the pipe are connected makes it possible to perform the connection (for example electrical) between these cables in a reliable and efficient manner. In particular, once the unitary section of pipe is connected to the pipe, it suffices to slide the female connector (and / or the male connector) vertically to connect them and ensure a connection between the cables. The electrical continuity between the cables is thus established in a simple, fast and efficient manner, which makes it possible not to increase the use time of the laying vessels.

It will also be noted that the female connector is advantageously chosen to be placed in the high position during assembly, so that the sockets intended to be connected to the pins of the male connector are oriented downwards to limit the risks of contamination by bodies. foreigners.

Preferably, the method further comprises, after connecting the male and female connectors, pivoting said connected connectors about a longitudinal axis of the unitary section of pipe. This manipulation thus makes it possible to perfectly press the cables against an outer surface of said unitary pipe section, so as not to harm the efficient heating of these cables.

Also preferably, the method further comprises injecting resin inside an annular cavity formed between the male and female connectors when they are assembled so as to provide electrical insulation of the connection between said connectors (this operation is typically carried out offshore).

Likewise, the connection of the cables to the male and female connectors advantageously comprises the injection of resin inside cavities internal to said connectors so as to ensure electrical insulation of the connection of the cables at their connection to said connectors (this operation is typically carried out onshore)

More preferably, the method further comprises maintaining by magnet at least the female connector on the single section of pipe to fix it vertically on the single section of pipe and prevent it from sliding vertically along the latter. under the effect of gravity.

The connection of the cables to the male and female connectors can comprise the screwing of crimped barrels on the ends of the cables on said connectors. In addition, the cables can be connected to the male and female connectors by being regularly distributed around a longitudinal axis of the unitary pipe section.

The subject of the invention is also a male connector for implementing the method as defined above, comprising a ring having an internal cavity in which a plurality of pins are housed for connecting cables.

Another subject of the invention is a female connector for implementing the method as defined above, comprising a ring having an internal cavity into which the ends of the cables to be connected emerge.

The internal cavity of the ring of these connectors preferably opens to the outside through at least one opening to allow resin injection inside the latter. In addition, the ring of these connectors advantageously comprises on an internal face at least one magnet.

Brief description of the drawings

Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate an exemplary embodiment thereof without any limiting nature. In the figures:

- Figures 1 to 3 are views of a female connector used for the connection method according to the invention, respectively in exploded view, in perspective and in profile;

- Figures 4 to 6 are views of a male connector used for the connection method according to the invention, respectively in exploded view, in perspective and in profile; and

FIGS. 7A to 7C are views of an exemplary implementation of the connection method according to the invention.

Detailed description of the invention

The invention applies to any type of fluid transport pipe, in particular to submarine coaxial pipes of the "Pipe in Pipe" (or "PIP") type, that is to say a pipe which comprises a tube. internal intended for transporting hydrocarbons from production wells and an external tube coaxial with the preceding one, also called “external envelope”, which is in direct contact with the surrounding water.

This type of subsea coaxial pipe is typically used in the offshore production of hydrocarbons at great depth. In the context of such installations, the subsea coaxial pipes can be assembled on land in several pipe sections of unit length (we also speak of "joints", in particular "double joints" for two unit elements assembled together, " triple joints ”for three unit elements assembled together,“ quadruple joints ”for four unit elements assembled together, or more generally“ quad-joints ”for quadruple sections of tube), of the order of 10 to 100 m depending on the holding capacity of the laying system. During installation, these elements of unit length of submarine pipe are connected to each other on board the ship and as and when they are laid at sea.

Typically, the internal tube of these coaxial conduits is covered with electrical and / or optical cables. Electric cables are used in particular to ensure heating by the Joule effect of the internal tubes and thus prevent the formation of troublesome phenomena inside the tubes which may hinder the proper circulation of fluids. As for optical cables, they can in particular be used to collect a certain number of data on the temperature or the stresses undergone in operation by the submarine pipe.

The method according to the invention aims to provide a connection between the cables (electrical and / or optical) of a new quad-joint (or unitary section of pipe) which must be assembled on the submarine pipe with the cables (electric and / or optics) of the latter; this assembly between the new quad-joint and the underwater pipe is carried out vertically at sea by a J-shaped laying tower.

To this end, the invention provides for positioning a female connector (such as that described below in conjunction with Figures 1 to 3) around a lower end of the new quad-joint and a male connector (such as that described hereinafter in conjunction with Figures 4 to 6) around a top end of the submarine pipe.

As shown in Figures 1 to 3, the female connector 2 is in the form of a ring having a longitudinal axis XX and formed of two annular parts 2a, 2b, for example made of plastic, assembled together by pins 4 regularly distributed around axis XX.

At its part 2a, the female connector comprises a plurality of sockets 6 regularly distributed around the X-X axis and emerging outside the female connector at the level of an annular recess 8.

At its part 2b, the female connector comprises a plurality of screw nuts 10 regularly distributed around the axis XX and aligned longitudinally with the sockets 6 with which they are in contact (electrical and / or optical). These screw nuts 10 are intended to receive by screwing the barrels 12 crimped at the free ends of the cables to be connected 14.

Furthermore, as shown in FIG. 1, part 2b comprises an internal annular cavity 16 formed opposite part 2a of the female connector and opening out to the outside thereof via two openings 18 (see FIG. 3: one of the openings 18 serving to ensure a vacuum draw from the internal cavity 16 and the other to inject resin therein).

The female connector 2 further comprises, at its internal face, several magnets 20 for fixing it vertically on the unitary pipe section (which is metallic) and preventing it from sliding vertically along the latter under the effect. of gravity.

Finally, at its outer face, the female connector further comprises two bores 22 opening out to the outside and opening inside the annular recess 8 at which the sockets 6 emerge (see FIG. 2: one of these holes 22 serving to ensure a vacuum draw and the other for resin injection).

As shown in Figures 4 to 6, the male connector 24 is in the form of a ring having a longitudinal axis YY and also formed of two annular parts 24a, 24b, for example made of plastic, assembled together by pins 22 regularly distributed around the YY axis.

At its part 24a, the male connector 24 comprises a plurality of pins 26 regularly distributed around the YY axis and opening to the outside of the male connector by projecting longitudinally outwardly relative to the latter (it It should be noted that the number of pins 26 is of course identical to the number of sockets 6 of the female connector).

At its part 24b, the male connector comprises a plurality of screw nuts 28 regularly distributed around the axis XX and aligned longitudinally with the pins 26 with which they are in contact (electrical and / or optical). These screw nuts 28 are intended to receive by screwing the barrels 30 crimped at the free ends of the cables to be connected 32.

Moreover, as shown more precisely in FIG. 4, part 24b comprises an internal annular cavity 34 formed opposite part 24a of the male connector and opening out to the outside thereof via two openings 36 ( see FIG. 6: one of the openings serving to ensure a vacuum draw of the internal cavity 34 and the other to inject resin therein).

The method of connection between the cables (electrical and / or optical) of a new quad-joint and the cables of the submarine pipe by means of the female 2 and male 24 connectors described above is described below in conjunction with the cables. Figures 7A to 7C.

Prior to this operation, the female connector 2 is positioned around a lower end of the internal tube 40a of the new quad-joint 40 to be assembled (maintaining the female connector in this position is made position thanks to the magnets 20 positioned on its internal face ) and the electrical and / or optical cables 14 extending along the quad-joint 40 are connected to this female connector. In this position, the pins of the female connector face down.

As indicated above, the drums 12 crimped at the free ends of these cables 14 are more precisely screwed onto the screw nuts 10 of the female connector. Once the cables 14 are connected to the female connector, resin (typically epoxy resin) is injected inside the internal cavity of the female connector (through the openings 18) so as to ensure perfect electrical insulation of the cables to the level of their connection to the female connector (this operation is carried out onshore).

Likewise, the male connector 24 is positioned around the inner tube 42a of the pipe 42 on which the quad-joint 40 is to be assembled and the electrical and / or optical cables 32 extending along the pipe are connected to this connector. male. In this position, the pins of the male connector face up.

For this purpose, the barrels 30 crimped at the free ends of these cables 32 are more precisely screwed onto the screw nuts 28 of the male connector and resin (typically epoxy resin) is also injected inside the internal cavity. connector (through the openings 36) so as to ensure perfect electrical insulation of the cables at the level of their connection with the male connector (this operation is carried out onshore).

As shown in FIG. 7A, the new quad-joint 40 to be assembled is then positioned vertically above the subsea pipe 42 by means of a J-tower (not shown). More precisely, the respective inner tubes 40a, 42a of the quad-joint 40 and of the underwater pipe 42 are assembled one on the other (by welding), the respective outer tubes 40b, 42b having been previously slid vertically to allow this to be done.

Once the respective internal tubes 40a, 42a of the quad-joint 40 and of the pipe 42 assembled together, the female 2 and / or male connectors 24 are slid vertically along the quad-joint and the pipe to allow their connection ( i.e. the electrical and / or optical connection between the pins of the male connector and the sockets of the female connector) - see figure 7B. The sliding of the female connector must be made possible despite the presence of the magnets on its internal face with sufficient force.

In this position, resin (typically epoxy resin) is injected into the internal annular cavity formed between the annular recess 8 of the female connector 2 and the part 24a of the male connector 24 provided with the pins 26 through the bores 22 (this operation is carried out offshore). This resin makes it possible to ensure, on the one hand, perfect electrical insulation between the sockets of the female connector and the pins of the male connector, and on the other hand a secondary fixing of the connectors to one another.

If necessary, the female 2 and male 24 connectors thus connected are then advantageously pivoted about a longitudinal axis ZZ of the quad-joint 40 so as to perfectly press the cables 14 against an outer surface of the quad-joint and the cables 32 against a outer surface of the pipe 42. Finally, once the female 2 and male 24 connectors are connected, the respective outer tubes 40b, 42b of the quad-joint 40 and of the underwater pipe 42 are slid vertically towards each other to allow their connection (Figure 7C).

It will be noted that the female and male connectors thus connected are preferably offset longitudinally with respect to the weld between the respective outer tubes of the quad-joint and of the pipe. Indeed, the flaming of the solder could damage the connectors.

It will also be noted that the male and female connectors and the connection method according to the invention have been described here in connection with a coaxial pipe of the PIP type. Of course, the present invention also applies to any other fluid transport pipe, in particular to simple pipes covered with composite materials.

Claims (12)

1. A method of connecting cables of a unitary section of pipe intended to be assembled vertically on an underwater pipe for transporting fluids, comprising: positioning around a lower end of the unitary section of pipe (40) of a female annular connector (2) to which are connected cables (14) extending along said unitary section of pipe; positioning around an upper end of the pipe (42) of a male annular connector (24) to which are connected cables (32) extending along said pipe; and connecting the male and female connectors by sliding them vertically towards each other when assembling the unitary section of pipe to the pipe. 2. Method according to claim 1, further comprising, after connecting the male and female connectors, the pivoting of said connected connectors about a longitudinal axis (ZZ) of the unit pipe section so as to press the cables (14). against an outer surface of said unit pipe section. 3. Method according to one of claims 1 and 2, further comprising the injection of resin inside an annular cavity formed between the male and female connectors when they are assembled so as to provide electrical insulation of the connection between said connectors. 4. Method according to any one of claims 1 to 3, wherein the connection of the cables to the male and female connectors comprises injecting resin inside internal cavities (16, 34) to said connectors so as to ensure a electrical insulation of the connection of the cables at their connection to said connectors. 5. Method according to any one of claims 1 to 4, further comprising maintaining by magnet (20) at least the female connector (2) on the unit pipe section to prevent it from sliding vertically along. of it under the effect of gravity. 6. Method according to any one of claims 1 to 5, wherein the connection of the cables to the male and female connectors comprises the screwing of barrels (12, 30) crimped onto the ends of the cables on said connectors. 7. Method according to any one of claims 1 to 6, wherein the cables (14, 32) are connected to the male and female connectors by being regularly distributed around a longitudinal axis of the unit pipe section. 8. Male connector (24) for implementing the method according to any one of claims 1 to 7, comprising a ring having an internal cavity (34) in which are housed a plurality of pins for the connection of cables. 9. A male connector according to claim 8, wherein the internal cavity (34) of the ring opens to the outside through at least one opening (36) to allow resin injection inside thereof. 10. A female connector (2) for implementing the method according to any one of claims 1 to 7, comprising a ring having an internal cavity (16) into which the ends of the cables to be connected emerge. 11. A female connector according to claim 10, in which the internal cavity (16) of the ring opens to the outside through at least one opening (18) to allow resin injection inside the latter. 12. A female connector according to one of claims 10 and 11, wherein the ring comprises on an internal face at least one magnet (20).