MX2010011122A

MX2010011122A - Device for extracting a material situated at the bottom of an expanse of water, extraction installation and associated method.

Info

Publication number: MX2010011122A
Application number: MX2010011122A
Authority: MX
Inventors: Philippe Espinasse
Original assignee: Technip France
Priority date: 2008-04-08
Filing date: 2009-04-07
Publication date: 2010-11-30
Also published as: NZ588463A; DK2288789T3; EP2288789A1; BRPI0911059A2; JP2011520046A; EP2288789B1; FR2929638B1; JP5390593B2; BRPI0911059B1; WO2009136064A1; FR2929638A1; PT2288789T

Abstract

This device comprises a bottom assembly (24) comprising means (50, 52) of gathering material from the bottom (14) of the expanse of water (12) and a pipe (26) for transporting the gathered material, the pipe being connected at a first point (60) to the bottom assembly (24) and connected at a second point (62) to a surface assembly (20). The bottom assembly (24) comprises means (36) of anchorage into the bottom (14) of the expanse of water (12). The extraction device (18) comprises a buoyancy assembly (28) completely immersed under the expanse of water (12). The buoyancy assembly (28) is secured to at least one upper region of the transport pipe (26) in order to keep the transport pipe (26) in a substantially vertical configuration in the expanse of water (12) between the bottom assembly (24) and the upper region when the second point (62) is disconnected from the surface assembly (20).

Description

MATERIAL EXTRACTION DEVICE LOCATED ON THE BACKGROUND OF A WATER BODY, EXTRACTION SYSTEM, AND PROCEDURE ASSOCIATED Field of the Invention The present invention relates to a device for extracting a material located at the bottom of a body of water, of the type comprising: a bottom unit comprising means for extracting the material on the bottom of the water body; - a transport conduit of the extracted material, connected in a first point on the unit of the bottom and destined to be connected in a second point to a unit of the surface that floats on the body of water.

Such devices are intended especially for the mining of undersea bottoms, or for earthmoving of underwater soils in order to place hydrocarbon production facilities.

Background of the Invention A device of the precipitated type is already known from FR-A-2 467 283. This device comprises an installation of the surface carried by a vessel and the bottom unit. The bottom unit comprises a base station and an extraction vehicle that circulates on the seabed and connected to the REF.214648 the base station by a flexible line designated by the English term "jumper (splice conductor)".

In order to lower the bottom unit in the water, it is already known to use a train of rigid hollow rods connecting the base station and the installation of the surface. The train of stems internally delimits a circulation passage of the material extracted from the bottom by transporting it to the surface.

One such device is thus satisfactory at the time of normal operation, in still water, of the extraction device.

However, in the event of a storm or when the installation of the surface on the vessel must be temporarily displaced, it is necessary to remount the unit of the train of rods that constitutes the transport conduit to the carrier vessel, as well as the underwater vehicle of extraction. of the material on the bottom of the water body and the pumping equipment.

One such operation is annoying and slow, which damages the security and the operating cost of the device.

An object of the invention is therefore to obtain a device for extracting a material located at the bottom of a body of water that is safer and less expensive in its operation.

For this purpose, the invention relates to a device of the above-mentioned type, characterized in that the bottom unit comprises means of anchoring at the bottom of the body of water, the extraction device comprises a buoyancy unit intended to be completely submerged in the body of water, the buoyancy unit is integral with at least one upper region of the transport conduit to maintain the transport conduit in a substantially vertical configuration in the water body between the bottom unit and the upper region when the second point is disconnected of the unit of the surface.

The device according to the invention may comprise one or more of the following characteristics, taken alone or following all the combination (s) technically possible: - the buoyancy unit comprises a plurality of buoys mounted around the upper region of the transport conduit; the transport duct comprises a rigid lower part connected to the bottom unit and a flexible upper part connected to the rigid bottom part, the buoyancy unit is mounted at least partly on the rigid bottom part; ' the transport duct is flexible substantially over its entire length and can be deployable between a configuration wound on a winding drum carried by the surface unit and a configuration deployed in the water body; the unit of. bottom comprises an extractor vehicle, connected to the transport conduit, the extraction means are carried by the extractor vehicle; Y - the bottom unit comprises a support for collecting the material, connected to the transport duct, the collection support is intended to be placed on the bottom of the body of water to collect the material extracted by the extraction means, the means of Extraction are intended to be maneuvered from the surface unit, regardless of the collection support.

Another object of the invention is an installation for extracting a material located at the bottom of a body of water, characterized in that it comprises: a unit of the surface intended to extend at least partially above the surface of the body of water, - an extraction device as defined above, the second point of the transport duct is displaceable with respect to the unit of the surface between a connected configuration in which the second point is connected to the surface unit and a disassembled configuration in which the second point is located completely away from the surface unit, the buoyancy unit keeps the transport conduit in a substantially vertical configuration in the body of water between the unit of the background and the upper region, in the connected configuration and in the disassembled configuration.

The subject of the invention is also a method of extracting a material located at the bottom of a body of water with the aid of an installation such as that described above, characterized in that it comprises the following steps: the connection of the second point of the transport duct on the unit of the surface; - the extraction of the material from the bottom of the body of water by the extraction means; the transport of the extracted material towards the unit of the surface through the transport conduit; then - the disconnection of the second point of the transport duct separated from the surface unit, the buoyancy unit keeps the transport duct in a substantially vertical configuration in the body of water between the bottom unit and the upper region after the disconnection .

The method according to the invention may comprise one or more of the following characteristics, taken alone or following all the combination (s) technically possible: - after the disconnection step, an additional step of connecting the second point of the transport conduit in the unit of the total surface; Y the installation comprises a first ship and a second ship, each ship carries a unit of the surface, the procedure comprises the following stages: - the connection of the second point of the transport conduit on the unit of the surface of the first vessel; - the extraction of the material from the bottom of the body of water by means of extraction, - the transport of the extracted material to the unit of the surface of the first vessel through the transport conduit, then - the disconnection of the second point of the transport pipe away from the unit of the surface of the first vessel, the buoyancy unit keeps the transport conduit in a substantially vertical configuration in the body of water between the bottom unit and the upper region, - the connection of the second point of the transport duct on the unit of the surface of the second ship.

The invention will be better understood upon reading the following description, given only as an example, and reference is made to the appended figures.

Brief Description of the Figures Figure 1 is a side view of a first extraction installation according to the invention, the surface vessel is connected to the extraction device; Figure 2 is a schematic side view of an upper part of the transport conduit provided with a buoyancy unit; Figure 3 is a view analogous to Figure 1 at the time of disconnection of the ship from the surface; Figure 4 is a view analogous to Figure 1 in the absence of the surface vessel; Figure 5 is a side view of a detail of the first extraction installation in a contracted position of the flexible upper part of the transport duct; Figure 6 is a view analogous to Figure 5 in an unfolded position of the flexible upper part of the duct; Figure 7 is a top view schematically illustrating the configurations of Figure 5 and Figure 6; Y Figure 8 is a curve representing the window of use of the extraction device of figures 5 to 7 as a function of the depth and distance of the vertical axis of the rigid part.

Detailed description of the invention An extraction installation 10 according to the invention is represented on FIGS. 1 to 4. This installation is intended to extract materials located at the bottom of a body of water 12 such as a sea, an ocean, or a lake.

The body of water 12 rests on a bottom 14 delimited by a solid material comprising rocks and / or sediments.

The purpose of the device 10 is, for example, to carry out grading works on the bottom 14 in order to place a hydrocarbon exploitation plant, or to extract minerals deposited on the bottom 14 for the purpose of its subsequent exploitation towards the surface 16 of the body. of water 12.

As illustrated by FIG. 1, the installation 10 comprises a submerged extraction device 18 and a unit of the surface 20 for collecting, processing and storing the extracted material and remounted to the surface by the extraction device 18.

In this example, the unit of the surface 20 is carried by a ship 22 that floats on the body of water.

The extraction device 18 comprises a unit from the bottom 24 for extracting the material on the bottom 14 of the water body 12, a transport conduit 26 connecting the bottom unit 24 to a unit of the surface 20, and, according to the invention, a buoyancy unit 28 mounted around at least one upper region of the transport conduit 26 to ensure its maintenance in a substantially vertical configuration in the water body 12.

The extraction device 18 further comprises functional lines 30 for power supply of the bottom unit 24 and for gas injection in the conduit 26.

The bottom unit 24 comprises a base station 32, digging means 34A, 34B, movable with respect to the base station 32, and a fixing anchor 36 of the base station 32 on the bottom 14 of the water body 12.

The base station 32 is intended to be placed in the vicinity of the bottom 14, away from that at the time of exploitation of the materials.

The base station 32 comprises equipment (not shown) for pumping and treating the extracted material, such as pumps or filters, and means for commanding the excavation means 34A, 34B. They may also comprise means for temporary storage of the material extracted by the excavation means 34A, 34B.

In the example depicted on figure 1, the digging means 34A, 34B comprise, to the left on the figure, an excavating vehicle 38 and a flexible line 40 connecting the excavating vehicle 38 to the base station 32, and to the right on the figure, an excavation crane 42, associated with the means 44 for receiving and processing the material, placed on the bottom 14 of the water body 12 and connected to the base station 32 by a second flexible line 46.

The excavating vehicle 38 is adapted to move on the bottom 14 to extract the material therefrom. It comprises means 48 for autonomous movement on the bottom 14, and means 50 for extracting the material suitable for excavating, polishing or perforating the material constituting the bottom 14 and for transporting it to the flexible line 40.

An example of an excavating vehicle is described in French application FR-A-2 467 283.

The flexible line 42 is sometimes referred to by the English term "jumper (splice conductor)". It is formed of a flexible pipe having an upper end connected on the base extension 32 and a lower end connected on the vehicle 38 for the extraction of the material emerged from the extraction means 50. It internally delimits a circulation port of the material that flows in front of the extraction means 50 and in the base station 32 to connect with the transport conduit 26.

The crane 42 is deployable and operable from the ship 22 on the surface. It comprises a clamp 52 for extracting the material on the bottom 14, and a cable 53 for deployment and displacement of the clamp 52 for descending from the ship 22 towards the bottom 14 and for moving it with respect to the bottom 14.

In one embodiment, the excavation means 34B further comprises a pick hammer integral with the clamp 52 or a chopper hammer deployed from the ship 22 at the surface by an additional deployment and displacement cable.

The reception means 44 are described, for example, in the French application No. 07 56579 of the applicant.

They comprise an adjustable support 54 placed on the bottom of the water body, provided with a mill / grinder and a funnel for receiving the extracted material.

The clamp 52 of the crane 42 is displaceable with respect to the support 54 between a position of extracting the material in contact with the bottom 14 of the water body and a position of pouring the material towards the support 54.

The second flexible line 46 is a structure analogous to that of the first flexible line 40.

The anchor 36 comprises a fixing pin in the bottom of the water body and a connection cable to the base station 32. The station 32 is thus maintained above the fixing pin a few meters away from the bottom 14.

The transport duct 12 extends substantially vertically in the water body 12 between a first point 60, located at its lower end and connected on the base station 32, and a second point 62 located at its upper end and movably connected about the unit of the surface 20.

The duct 26 comprises, with reference to Figure 1, a rigid bottom 64, a flexible top 66 and a link 68 between the rigid part and the flexible part.

The transport conduit 26 internally defines, over its entire length taken between the first point 60 and the second point 62, a continuous inner port 70 for circulating the material, intended to transport the extracted material on the bottom 14 of the water body from the base station 32 to the unit of surface 20.

In the example illustrated by Figure 1, the rigid bottom 64 comprises an end-to-end assembly of the sections 72 of rigid metal tubes.

The maximum radius of curvature of the rigid conduit is less than 12 m and especially less than 10 m.

As will be seen below, and according to the invention, thanks to the buoyancy unit 28 and the anchor 36, the lower part 64 extends along a substantially vertical axis AA 'between the connector 68 and the base station 32 regardless of the configuration of the flexible upper part 66.

The lower part 64 'is provided, in addition to two reinforcements 73 located in the vicinity of the connector 68.

The connector 68 is located at a depth comprised between 1 m and 200 m below the surface 16.

The flexible upper part 66 is made of a flexible duct 74 having a minimum radius of curvature greater than 12 m.

The flexible top 66 is also capable of being deformed between an S-connected configuration, in which it is connected to the surface unit 20, such as that shown in Figure 1, and a reverse U-shaped configuration in the which is disconnected from the unit of the surface 20 and the same extends down parallel with respect to the rigid part 64, such as that shown on Figure 4.

In the configuration connected in S; the second point 62 is held connected on the unit of the surface 20 above the connector 68. The flexible conduit 74 forms from the connector 68 towards the second point 62, an elbow 75A directed upwards, an elbow 75B directed downwards, then a substantially vertical section 75C.

The flexible top 66 is provided, in the vicinity of the first point 62, with a recovery cable 80 having a buoy 82 floating on the surface at the upper end of the cable 80.

In one embodiment, the flexible upper part 66 is devoid of the cable 80 and the buoy 82. The first point 62 is then suitable for resting on the water body 12 or on the bottom 14 of the water body when it is disconnected from the body. the unit of the surface 20.

The functional lines 30 comprise the lines 90 for transporting electric power and / or hydraulic power, and for transporting the information for feeding the excavating devices 34A, 34B and the base station 32, and at least one line 92 of gas injection in the inner port 70 of the transport conduit 26 for transporting the material from the base station to the unit of the surface 20.

The transport lines 90 are for example made in the form of umbilical cables with a free upper section with respect to the conduit 26, an intermediate section fixed along the conduit 26 opposite the rigid part 64 and a free inner section with respect to the duct 26 that splices the intermediate section respectively with excavator vehicle 38 and support 54.

According to the invention, the buoyancy unit 28 comprises a plurality of buoys 96, 98 axially distributed along the transport conduit 26.

As illustrated by Figure 2, the transport conduit 26 thus comprises a first group of buoys 96 mounted coaxially around the inner part 64 and a second group of buoys 68 mounted around the flexible upper part 66.

The buoys 96, 98 are made for example of impermeable foam and are fixed axially around the conduit 26 by the intermediation of the clamps, such as those described in the patent application GB 2 288 205 of the English company CRP.

In the example shown, the buoys 96, 98 are distributed substantially over the entire length of the conduit 26.

In one embodiment, the buoys 96, 98 are placed only on an upper region of the conduit 26 in the vicinity of the connector 68, defining on the rigid lower part 64 and on the flexible upper part 66 regions devoid of buoys 96, 98 of greater length at 50% of the length of the conduit 26.

In this case, the upper region provided with buoys 96, 98 has a buoyancy higher than buoyancy from other regions of the canal 26.

The buoys 96, 98 are dimensioned to keep the rigid part 64 substantially vertical in the water body 12 in compensation with the weight of the conduit 26 and the fluid possibly contained in this conduit, in the case where the second point 62 is connected with the unit of the surface 20 or when the second point 62 is disconnected from the unit of the surface 20, in the absence of the vertical pull on the second point 62.

The buoys 96, 98 thus exert on the duct 26 a force directed towards the top, higher than the force resulting from the difference between, on the one hand, the weight of the duct 26 and its content, and on the other hand, the thrust of the duct 26. Arguímedes that is exerted on the conduit 26.

In another embodiment, the buoyancy unit 28 comprises a single buoy 96 made from a hollow shell completely immersed in the body of water. The single buoy is deposited vertically above the connector 68 and is connected to the connector 68 by a chain.

The unit of the surface 20 comprises means 100 for receiving, decanting and treating the material received from the transport conduit 28, the electrical and / or hydraulic power means 102 and the command or the excavation means 34A, 34B and the gas injection means 104 in line 92.

The assembly and operation of the extraction installation 10 according to the invention will now be described.

Initially, the extraction device 18 is sequentially assembled and lowered towards the bottom 14 of the water body.

For this purpose, the base station 32 and the excavation means 34A, 34B are progressively lowered towards the bottom 14 of the water body 12 from the vessel 22 by the successive assembly of the tube sections 72 forming the rigid bottom part 64 of the transport conduit 26.

At the time of assembling the rigid part 64, the buoys 96 are mounted regularly around the sections of the tubes 72 and are axially drawn around these tubes 72 to form the buoyancy unit 28.

Then, the connector 68 is mounted to the upper end of the rigid bottom 64. The flexible conduit 74 provided with the buoys 98 is then assembled and lowered into the water body 12 to form the sensitive upper portion 66 of the water conduit. transport 26, which occupies its configuration connected to the surface unit 20.

On the other hand, the functional lines 30 are unwound from the rotating drums placed on the ship 22 and are lowered simultaneously with the transport conduit 26.

When the base station 32 is located a few meters above the bottom 14 of the water body 12, the anchor 36 is put in place and its fixing pin is immobilized in the bottom 14 of the water body.

The buoys 96, 98 and the buoyancy unit 28 generate an upward pulling force on the upper region of the transport conduit 26 provided with the buoys 96, 98, and the anchor 36 generate a holding force of the lower end 60 of the transport duct 26 in the vicinity of the bottom 14 of the water body 12, the rigid bottom 64 of the transport duct 26 is aligned spontaneously and permanently along a substantially vertical axis AA 'between the anchor 36 and the connector 68.

In addition, the flexible upper part 66 assumes a conformation in a vague shape that absorbs the local displacements of the ship 20 with respect to the rigid part 64.

The excavation means 34A, 34B are then activated to remove the bottom material 14 from the water body 12 and to carry the extracted material through the respective flexible lines 40, 46 to the base station 32.

Then, the extracted material is traced through the inner port 70 of the transport conduit 26 between the base station 20 and the receiving and receiving means. treatment 100 on the unit of the surface 20, especially under the effect of the gas injected by the gas injection line 92 into the port 70, and / or for the centrifugal pumps mounted on the base station 32 or on the anchor support 36 .

In the case of storm or in case of emergency, the first point 62 can be disconnected very quickly from the surface unit 20 to be placed apart from the ship 22 in the water body 12, so that the upper part 66 occupies its disassembled configuration illustrated by figure 3.

Once disconnected, the ship 22 can quickly move away from the extraction device 18, especially when a storm agitates the body of water 12.

However, just as when the second point 62 is disconnected,. the transport conduit 26 remains substantially vertical in the water body 12, especially in the rigid bottom 64 between the base station 32 and the connector 68, as illustrated by Figure 4.

On the other hand, when the second point 62 of the conduit must be reconnected to a unit of the surface 20, it can be pulled on a ship 22 towards the surface 16 by the intermediation of the recovery cable 80 that can be picked up with the help of the buoy 82.

The extraction device 18 according to the invention can thus be left permanently immersed in the water body 12 in a substantially vertical configuration, without having to upload it to a vessel 22 when it is not used.

As illustrated by figures 4 to 8, the extraction device 18 according to the invention, when equipped with digging means 34B comprising a crane 42 integral with the ship associated with the means 44 for receiving treatment of the material placed on the The bottom of the body of water has a large radius of intervention on the bottom 14 of the body of water, just as when the second point 62 is kept connected on the unit of the surface 20, and when the anchor 36 is kept immobile on the bottom 14 of the body of water.

Thus, with reference to Figure 7, for each position of the ship 22, the clamp 52 located at the lower end of the crane 42 which is suitable for treating, in the projection on, the bottom 14, a surface 130 in the form of a disk centered on the ship 22. In addition, the ship 22 can rotate 360 degrees around the axis A-A ', authorizing a treatment of an annular surface 132 centered on the axis AA', correspondingly displacing the support support 54 for place it on the surface in the shape of disk 130.

As illustrated by Figures 5, 6 and 7, the extension of the annular surface of the treatment 132 about the axis A-A 'is defined by the S-shaped configuration of the flexible upper part 66.

Thus, when the flexible upper part 66 occupies its S configuration, it is able to be displaced by the ship 22 between a radially contracted position, shown on Figure 5, in which the second point 62 connected on the unit of the surface 20 is positioned in the vicinity of the vertical axis AA 'of the rigid bottom 64, and a radially deployed position, shown on Figure 5, in which the second point 62 is further distanced from the vertical axis AA' of the bottom part 64 As illustrated by FIG. 5, in the radially contracted position, the angle T formed by a vertical axis BB 'passing through the second point 62 and the upper section of the flexible upper part 66 is less than -10 ° and is included in FIG. for example between -15 ° and -20 °.

As shown to the left on FIG. 7, the ship 22 is then placed in the vicinity of the axis A-A 'and defines with the crane 42 the minimum radius Dmin of the annular surface of the intervention 132.

On the contrary, in the radially deployed position, the angle T formed by the vertical passing through the second point 62 and the vertical section is greater than 10 °, it is for example comprised between 12 ° and 20 °.

As it is represented on the right on the figure 7, the ship 22 is then located farther from the axis A-A 'and defines with the crane 42, the maximum radius Dmax of the annular intervention surface 132.

In addition, the intermediate height h of the flexible upper portion 66 of the duct 26, taken between the tip 134 of the elbow directed upwards 75A and the lower point 136 of the downwardly directed elbow 75B, is adapted to the depth of the bottom 14 of the body of water, for a given length of the transport conduit 26.

For a transport conduit 26 having a rigid lower portion 64 of the given length II, for example comprised between 700 and 1000 m and a flexible upper portion 66 of the given length 12, for example between 400 m and 450 m, it is also possible extract the material on an annular surface 132 of the bottom 14 of the water body defined in the window of the depth P and of the distance D on the axis AA 'located inside the closed curve 140 substantially trapezoidal of figure 8, without having modified the length of conduit 26, and without having to displace it.

In a first embodiment of device 18,. the surface unit 20 of the first ship 22 is used to collect the material left from the transport conduit 26 until a given quantity of the material is recovered from the receiving and treatment means 100 of the first ship 22.

Then, the first point 62 of the conduit 26 is disconnected from the surface unit 20 of this first ship 22 and the first ship 22 moves away from the device 18.

A second vessel (not shown), carrying means for storing the available material, is then brought in front of the extraction device 18 and the first point 62 of the conduit is then connected to the unit of the surface 20 of this second vessel.

In yet another embodiment, the transport conduit 26 is flexible substantially over its entire length and each functional line 30 is positioned around the transport conduit 26 to form a flexible conduit as described in French application No. 07 56579 of the Applicant.

In this embodiment, the transport conduit 26 and each functional line 30 are deployable together between a rest configuration wound on a winding drum positioned on the laying vessel 22 and a deployed configuration towards the bottom 14 of the water body 12.

In another embodiment, the extraction device 18 is moved towards its unit, after the second point 62 detached from the unit of the surface 20, from a first anchor point of the anchor 36 on the bottom 14 of the water body towards a second anchorage point of the anchor 36 on the bottom 14 of the water body, without rising towards the conduit 26 and the bottom unit 24 on the surface unit 20.

For this purpose, a vessel (not shown) carrying a crane is used to partially lift the conduit 26 and the anchor 36 removed from the bottom 14 at the first anchor point, which penetrates the conduit 26 for example at the level of the connector 68. Then, the vessel transports the extraction device 18 to the second anchor point, where the conduit 26 and the anchor 36 are lowered to place the anchor 36 in contact with the bottom 14. The conduit 26 and the anchor 36 remain submerged under the surface 16 of the water body 12 during transport between the first anchor point and the second anchor point. The buoyancy provided by the buoyancy unit 28 facilitates the penetration of the extraction device 18 and authorizes its transport keeping the rigid bottom 64 substantially vertical.

In one embodiment, the flexible top 66 occupies a catenary configuration in the configuration connected The anchor 26 is, for example, the type of suction anchor ("suction pile" in English) or the type of gravity anchor pile ("gravity base" in English).

It is noted that in relation to this date the best method known by the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A device for extracting a material comprised of rocks and / or sediments located at the bottom of a body of water, of the type comprising: a bottom unit comprising means for extracting the material on the bottom of the water body; - a transport conduit for the extracted material, connected at a first point on the bottom unit and intended to be connected at a second point to a unit of the surface that floats on the body of water; characterized in that the bottom unit comprises anchoring means in the bottom of the water body, the extraction device comprises a buoyancy unit intended to be completely submerged under the body of water, the buoyancy unit is integral with at least one upper region of the transport conduit to maintain the transport conduit in a substantially vertical configuration in the water body between the bottom unit and the upper region when the second point is disconnected from the surface unit.

2. The device according to claim 1, characterized in that the unit of buoyancy comprises a plurality of buoys mounted around the upper region of the transport conduit.

3. The device according to any of claims 1 or 2, characterized in that the transport conduit comprises a rigid lower part connected to the bottom unit and a flexible upper part connected to the rigid bottom part, the buoyancy unit is mounted at least partially on the rigid bottom.

4. The device according to any of claims 1 or 2, characterized in that the transport conduit is flexible substantially over its entire length so that it can be deployed between a configuration wound on a winding drum carried by the unit of the surface and a configuration deployed in the body of water.

5. The device according to any of the preceding claims, characterized in that the bottom unit comprises an extractor vehicle, connected to the transport conduit, the extraction means are carried by the extractor vehicle.

6. The device according to any of the preceding claims, characterized in that the bottom unit comprises a support for collecting the material, connected to the transport conduit, the collection support is intended to be placed on the bottom of the body of water to collect the material extracted by the extraction means, the extraction means are intended to be maneuvered from the unit of the surface, independently of the collection support.

7. The device according to any of the preceding claims, characterized in that the anchoring means comprise an anchor maintained motionless in the bottom of the body of water.

8. The extraction installation of a material located at the bottom of a body of water, characterized in that it comprises: - a unit of the surface intended to extend at least partially above the surface of the body of water, - an extraction device according to any of the preceding claims, the second point of the transport duct is movable with respect to the unit of the surface between a connected configuration in which the second point is connected to the unit of the surface and a disassembled configuration in which the second point is located completely apart from the unit of the surface, the buoyancy unit keeps the transport conduit in a substantially vertical configuration in the body of water between the bottom unit and the upper region, in the connected configuration and in the disassembled configuration.

9. A method of extracting a material located at the bottom of a body of water with the help of an installation according to claim 8, characterized in that it comprises the following steps: the connection of the second point of the transport duct on the unit of the surface; - the extraction of the material from the bottom of the body of water by the extraction means; - the transport of the extracted material towards the unit of the surface through the transport conduit; then - the disconnection of the second point of the transport duct separated from the surface unit, the buoyancy unit keeps the transport duct in a substantially vertical configuration in the body of water between the bottom unit and the upper region after the disconnection .

10. A method according to claim 9, characterized in that it comprises, after the disconnection step, an additional step of connecting the second point of the transport conduit with the unit of the surface.

11. The method according to claim 9 or 10, wherein the installation comprises a First vessel and a second vessel, each vessel carries a unit of the surface, characterized in that it comprises the following stages: the connection of the second point of the transport conduit on the unit of the surface of the first vessel; - the extraction of the material from the bottom of the body of water by means of extraction, the transport of the extracted material towards the unit of the surface of the first vessel through the transport conduit, then - the disconnection of the second point of the transport pipe away from the unit of the surface of the first vessel, the buoyancy unit keeps the transport conduit in a substantially vertical configuration in the body of water between the bottom unit and the upper region, the connection of the second transport duct point on the unit of the surface of the second vessel.