NZ582682A

NZ582682A - Device and method for extracting a material from the bed of a body of water

Info

Publication number: NZ582682A
Application number: NZ582682A
Authority: NZ
Inventors: Pierre-Armand Thomas
Original assignee: Technip France
Priority date: 2007-07-18
Filing date: 2008-07-17
Publication date: 2011-11-25
Also published as: JP5373786B2; JP2010533808A; EP2171163B1; WO2009013434A2; EP2171163A2; PT2171163T; FR2919016B3; BRPI0814574B1; FR2919015A1; FR2919015B1; FR2919016A1; BRPI0814574A2; WO2009013434A3

Abstract

The invention relates to a device for extracting a material from the bed of a body of water and to the associated method. The device (10) includes a surface apparatus (18), a bed unit (22) with material-collection means (34) and a pipe for conveying said material between the surface apparatus (18) and the bed unit (22). The device (10) includes at least one functional line which is flexible along almost all of the length thereof. The surface apparatus (18) includes at least one drum (68) around which the functional line or lines are wound. The carrier tube is also flexible along almost all of the length thereof, each functional line being disposed around the carrier pipe in order to form a flexible umbilical line (24). The carrier pipe and each functional line can be deployed together between a rest configuration in which they are wound around the drum (68) and a deployed configuration in which they are deployed towards the bed (14) of the body of water (12). The invention is suitable for earthwork, mining and dredging on sea beds.

Description

RECEIVED at IPONZ on 26 September 2011 i 1 Device for extracting a material from the bed of a body of water and associated method The present invention relates to a device for extracting a material from the bed of a 5 body of water, of the type comprising: - a surface apparatus which is to extend at least partially above the surface of the body of water; - a bed unit comprising means for removing material from the bed of the body of water; - a material transport pipe which connects a first point situated on the surface apparatus to a second point situated on the bed unit, the transport pipe delimiting at least one material circulation passage; - at least one functional line which is flexible over substantially its entire length and which connects the bed unit to the surface apparatus, the functional line being capable of transmitting electric or hydraulic power, information or a fluid between the surface apparatus and the bed unit, the surface apparatus comprising at least one drum around which the or each functional line is wound.

This device is applicable, for example, to the mining of ocean beds or to undersea 20 excavation works for the installation of hydrocarbon production equipment.

A device of the above-mentioned type is known from FR-A-2 467 283. That device comprises a surface apparatus carried by a ship, and a bed unit. The unit comprises a base station and an extraction vehicle which travels over the sea bed 25 and is connected to the base station by a flexible link known as a "jumper".

The base unit is lowered into the water with the aid of a string of rigid rods, which connects the base station to the surface apparatus. The string of rods delimits, on the inside, a passage for the circulation of the material removed from the bed, in 30 order to convey it to the surface.

Furthermore, a line for injecting gas into the string of rods, and power transfer lines forming a link designated by the term "umbilical", are lowered into the sea towards RECEIVED at IPONZ on 26 September 2011 2 (followed by page 2a) the intermediate station from the ship. An example of an umbilical is described in application GB 2 395 539.

In order to deploy the device, it is necessary to mount each rod of the string of rods in 5 succession on the ship at the surface during lowering of the bed unit, and then simultaneously lower the gas injection line and the umbilical comprising the power lines, by assembling them on each rod.

Consequently, the ship must have a very large storage space for assembling and 10 storing the rigid tubes and the umbilical.

An object of at least preferred embodiments of the invention is to obtain a device for extracting a material from the bed of a body of water which is simple to use and is compact.

A first aspect of the present invention relates to a device for extraction of a material from the bed of a body of water, of the type comprising: - a surface apparatus which is to extend at least partially above the surface of the body of water; - a bed unit comprising means for removing material from the bed of the body of water; - a material transport pipe which connects a first point situated on the surface apparatus to a second point situated on the bed unit, the transport pipe delimiting at least one passage for circulation of material; - at least one functional line which is flexible over substantially its entire length and 25 which connects the bed unit to the surface apparatus, the functional line being capable of transmitting electric or hydraulic power, information or a fluid between the surface apparatus and the bed unit, the surface apparatus comprising at least one drum around which the or each functional line is wound; wherein the transport pipe is flexible over substantially its entire length, the or each 30 functional line being arranged around the transport pipe to form a flexible pipe, the transport pipe and the or each functional line being deployable RECEIVED at IPONZ on 26 September 2011 2a (followed by page 3) conjointly between a rest configuration, in which they are wound on the winding drum, and a configuration in which they are deployed towards the bed of the body of water.

The device according to the invention can have one or more of the following features, taken in isolation or in any technically possible combination(s): - the flexible pipe comprises an annular layer surrounding the transport pipe, the layer delimiting longitudinal passages for receiving the or each functional line, into which passages the or each functional line is inserted; - the surface apparatus comprises a ship, the drum being mounted for rotation on a platform of the ship; - the ship delimits a lateral edge, the flexible pipe being deployed transversely towards the outside of the ship opposite the lateral edge; - the flexible pipe comprises a plurality of sections assembled end to end; RECEIVED at IPONZ on 26 September 2011 3 - each section comprises a tubular portion and, at each end of the tubular portion, a flange for connection to an adjacent section, the transverse dimension of the flange being greater than that of the central portion, and the drum delimits: - a support surface for the pipe, and - at least one groove for receiving the connection flanges of at least two adjacent sections, displaceable around the support surface, said flanges being inserted into the groove when the flexible pipe is in its wound configuration; - the bed unit comprises a base and an extractor vehicle which is connected to the 10 base by a flexible link delimiting a material transport port, the port opening into the circulation passage and opposite the removal means; - the surface apparatus comprises a gas/liquid/solid separator which delimits a separation chamber connected to the circulation passage; - the separation chamber comprises: • an outlet for evacuation of a solid separated in the separation chamber, and • a valve for closing off the evacuation outlet, which valve is capable of being controlled in order to maintain the separation chamber at a pressure greater than atmospheric pressure during the discharge of material issuing from the circulation passage into the separation chamber; - the flexible pipe comprises at least one line for the injection of gas for carrying the material, the gas injection line opening into the circulation passage away from the surface apparatus, the surface apparatus comprising a compressor which has an inlet connected to the separator and an outlet connected to the gas injection line; - in the deployed configuration, the flexible pipe comprises at least one unit for injecting liquid under pressure into the circulation passage, the liquid under pressure being capable of carrying the material towards the surface apparatus; - the winding drum delimits an interior space, the separation chamber being arranged at least partially in the interior space; - the bed unit comprises an extractor vehicle equipped with removal means; and - the bed unit comprises a material collection support, connected to the flexible pipe, the collection support being intended to be placed on the bed in order to RECEIVED at IPONZ on 26 September 2011 4 (followed by page 4a) collect the material removed by the removal means, the removal means being deployable from the surface apparatus independently of the collection support.

The invention relates further to a method of extracting a material from the bed of a body 5 of water with the aid of a device according to the first aspect, the method being of the type comprising the following steps: - positioning the surface apparatus opposite a region of the bed from which the material is to be extracted, the flexible pipe being wound around the winding drum in its rest configuration; - deploying the flexible pipe into its deployed configuration by unwinding it from the winding drum in order to immerse it conjointly with the bed unit until the removal means reach said region of the bed; - extracting the material from said region of the bed by the removal means, and conveying the extracted material towards the surface apparatus through the circulation passage of the transport pipe.

The term "comprising" as used in this specification and claims means "consisting at least in part of. When interpreting statements in this specification and claims which include the "comprising", other features besides the features prefaced by this term in 20 each statement can also be present. Related terms such as "comprise" and "comprised" are to be interpreted in similar manner.

The invention will be better understood from reading the following description, which is given solely by way of example and with reference to the accompanying drawings, in 25 which: - Figure 1 is a side view, in diagrammatic form and in partial perspective, of a first extraction device according to the invention, with its flexible pipe deployed; - Figure 2 is a partially cutaway view, in diagrammatic form, of a detail labelled II in Figure 1; - Figure 3 is a partially exploded view, in diagrammatic form and in perspective, of the flexible pipe of the first device according to the invention; RECEIVED at IPONZ on 26 September 2011 4a (followed by page 5) - Figure 4 is a partial view in diagrammatic form, in three-quarter perspective, of the winding drum for the flexible pipe of Figure 1, the flexible pipe being partially wound around the drum; - Figure 5 is a view analogous to Figure 4 of the drum without the pipe; - Figure 6 is an end view, taken according to arrow VI of Figure 4; - Figure 7 is a view taken in partial section according to the longitudinal vertical plane VII of Figure 4; RECEIVED at IPONZ on 26 September 2011 - Figure 8 is a view analogous to Figure 2 of a second device according to the invention comprising a unit for pumping by injection of water; - Figure 9 is a view analogous to Figure 8 of a third device according to the invention; - Figure 10 is a view in transverse section according to plane X-X of Figure 9; and - Figure 11 is a view analogous to Figure 1 of a fourth device according to the invention.

An extraction device 10 according to the invention is shown in Figures 1 to 10. The 10 device 10 is intended for removing materials from the bed of a body of water 12 such as a sea, an ocean or a lake.

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

The purpose of the device 10 is, for example, to carry out excavation work on the bed 14 in order to install hydrocarbon exploitation equipment, or to remove minerals deposited on the bed 14 for the subsequent exploitation thereof at the surface 16 of the body of water 12.

As is shown in Figure 1, the device 10 comprises a surface apparatus 18 carried by a ship 20, a bed unit 22 for removing material from the bed 14 of the body of water 12, and, according to the invention, a flexible pipe 24 of the integrated production bundle type for connecting the bed unit 22 to the surface apparatus 18.

The bed unit 22 comprises a base station 26 fixed to the lower end of the pipe 24, an excavator vehicle 28, which is in contact with the bed 14 of the body of water 12, and a flexible link 30 which connects the vehicle 28 to the base station 26.

% The base station 26 is to be placed in the vicinity of the bed 14, at a distance therefrom during the extraction of materials. The base station 26 comprises equipment (not shown), such as, for example, pumps or filters, for pumping and RECEIVED at IPONZ on 26 September 2011 6 treating the material that is removed, and means for controlling the excavator vehicle 28.

The excavator vehicle 28 is to come into contact with the bed 14 in order to 5 remove material from the bed 14. It comprises means 32 for displacement on the bed 14 and means 34 for removing material, capable of digging, scraping or drilling the material constituting the bed 14 and of transporting it to the flexible link 30.

The bottom of the base station 26 is provided with a trap 26A (Figure 1), which pivots by suitable means (not shown). In its open position, the trap 26A allows the material locked in the base station 26 to be evacuated. In that case, the excavator vehicle 28 is located beneath the base station 26 and the material falls into the vehicle 28, where it is ground.

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

The flexible link 30 is sometimes referred to as a "jumper". It is formed by a flexible 20 hollow tube which has an upper end connected to the base station 26 and a lower end connected to the vehicle 28, in order to remove the material issuing from the removal means 34. The flexible tube 36 delimits on the inside a port 37 for circulation of the material, which port 37 opens opposite the removal means 34 and into the base station 26.

The flexibility of the flexible link 30 is greater than that of the flexible pipe 24.

The vehicle 28 is movable relative to the base station 26, especially on the bed 14, up to a maximum distance from the base station 26 which is substantially equal to 30 the length of the flexible tube 36. The maximum distance is from 10 m to 40 m and is preferably less than 50 m.

RECEIVED at IPONZ on 26 September 2011 7 As is shown in Figures 1 and 2, the flexible pipe 24 extends between a first point 38 situated at its upper end on the surface apparatus 18, and a second point 40 situated at its lower end on the base station 26.

According to the invention, the pipe 24 is flexible over its entire length, taken between points 38, 40. Accordingly, as will be seen hereinbelow, the pipe 24 is capable of being wound on a rotary drum between an unwound configuration and a helically wound configuration, in which it occupies a bending radius of from 12 m to 15 m and preferably less than 20 m.

As is shown in Figures 2 and 3, the flexible pipe 24 comprises a central pipe 42 for transporting the material removed from the bed 14, from the base station 26 to the surface apparatus 18.

The pipe 24 further comprises, around the pipe 42, an outer functional layer 43 which receives functional lines 44 capable of transmitting electric or hydraulic power, information and/or fluids from the surface apparatus 18 to the bed unit 22, the lines 44 being arranged in the outer layer 43 around the transport pipe 42.

The pipe 24 also comprises a line 46, arranged in the layer 43, for the injection of gas for carrying the material into the transport pipe 42, and an outer protective sheath 47 arranged around the layer 43.

The transport pipe 42 complies generally with standard API 17J. It is flexible over its entire length. It comprises, for example, from the inside to the outside, an inner tubular metal casing 47A for providing pressure resistance, a plastics sheath 47B for providing tightness with respect to gases, an outer casing 47C and two layers of armouring wires 47D for providing traction resistance.

The transport pipe 42 delimits on the inside a passage 48 for circulation of material that has been removed, which passage 48 opens on the one hand at the first point 38 and on the other hand at the second point 40. The transport pipe 42 is mounted RECEIVED at IPONZ on 26 September 2011 8 in series with the flexible tube 36, so that the inner port 37 opens into the passage 48.

The layer 43 is generally annular in shape. It is arranged externally around the 5 transport pipe 42 and delimits on the inside longitudinal passages 48A for receiving the lines 44, 46, into which passages the lines 44, 46 are inserted.

The functional lines 44 include, for example, a power transfer line which connects the surface apparatus 18 to the bed unit 22 electrically in order to supply electrical 10 power to the base station 26 and the vehicle 28. The lines 44 further include an information transport line which connects the surface apparatus 18 to the control means on the base station 26 for controlling the vehicle 28.

The length of the flexible pipe 24, taken between the first point 38 and the second 15 point 40, is variable according to the depth at which the sea bed is located, and is preferably greater than 1000 m.

In the example shown in Figure 1, the flexible pipe 24 is formed by assembling, end to end, a plurality of individual flexible sections 50 having a length of 20 preferably from 300 m to 400 m.

Each section 50 accordingly comprises a central tubular portion 52 and, at each end, a flange 54 for fixing to an adjacent section 50.

As is shown in Figure 2, the flanges 54A, 54B of two adjacent sections 50 are fixed to one another by screwing, for example.

The flanges 54A, 54B project radially outwards relative to the central portion 52. They have an outside diameter greater than the average outside diameter of the 30 central portion 52.

RECEIVED at IPONZ on 26 September 2011 9 Each individual section 50 delimits part of the interior passage 48 and carries an individual section of the lines 44 and 46 which are connected together through the fixing flanges 54A, 54B.

The ship 20 delimits a support platform 60 for the surface apparatus 18, which platform extends between two lateral edges 62 of the ship.

The ship 20 further comprises a work station 63 equipped with a clamp 64 for selectively holding the pipe 24, which clamp projects from a lateral edge 62. The 10 pipe 24 is engaged vertically through the clamp 64 above and opposite a lateral edge 62.

As is shown in Figures 1 to 7, the surface apparatus 18 comprises a drum 68 for winding the flexible tube 24, means 70 for driving the drum 68 in rotation, a 15 separator 72, arranged in the drum 68, for treating the material that has been removed, and a compressor 74 for injecting gas into the interior passage 48 through the gas injection line 46.

As a function of the winding or unwinding of the flexible pipe 24 on the drum 68, 20 the work station 63 moves on a rail 64A arranged on a side of the ship 20.

As is shown in Figure 2, the surface apparatus 18 further comprises control means 76 and power supply means 78.

As is shown in Figures 4 and 5, the winding drum 68 extends according to a substantially horizontal longitudinal axis X-X' of the ship 20.

The drum 68 comprises a hollow cylinder 80 which has at its left- and right-hand ends transverse collars 82 for immobilizing the flexible pipe 24.

The cylinder 80 delimits a cylindrical outer surface 84, which is to receive the wound pipe 24 in abutment, and a cylindrical interior space 86 into which the separator 72 is inserted.

RECEIVED at IPONZ on 26 September 2011 As is shown in Figure 5, the drum 68 further has, on at least one circumference taken along the outer surface 84, two wedges 88 for supporting two adjacent sections 50 of the pipe.

The wedges 88 project relative to the outer surface 84 and delimit between them a longitudinal groove 90 which is to receive the fixing flanges 54 of two adjacent sections 50.

Accordingly, when the flanges 54 are introduced into the groove 90, the central portions 52 of the two adjacent sections each rest on one of the wedges 88, which limits their bending radius close to the flange 54. The risks of the pipe 24 being damaged by torsion are thus limited.

The wedges 88 are movable conjointly about the axis X-X' on at least one periphery of the surface 84.

More generally, the drum 68 may be used for winding any flexible pipe.

In the example shown in Figures 1 to 7, the diameter of the drum 68 is from 12 m to 15 m and is in any case less than 20 m.

The drum 68 is further equipped, inside the interior space 86, with rollers 92 which are located in the vicinity of the end collars 82 and are distributed about the axis 25 X-X'. The rollers 92 are arranged in abutment on an outer surface of the separator in order to allow the drum 68 to rotate about the axis X-X' by rolling on the separator 72, as will be seen hereinbelow.

The means 70 for driving the drum in rotation comprise, at each end of the rotary cylinder 80, an outer toothed ring 94 and two motorized drive wheels 96 which mesh with the toothed ring 94.

RECEIVED at IPONZ on 26 September 2011 11 Each ring 94 extends from the outer surface 84 on a periphery about the axis X-X*. It is integral with the cylinder 80. ;The wheels 96 are mounted to be movable in rotation on the platform 60 on either 5 side of a vertical plane passing through the axis of rotation X-X' of the cylinder. The drive wheels are capable of making the drum 68 rotate about the axis X-X' in two distinct directions of rotation in order to wind or unwind the flexible pipe 24. ;As is shown in Figures 6 and 7, the separator 72 comprises a cylindrical vessel 10 100 arranged in the interior space 86, a tank 102 for holding the material separated in the cylindrical vessel 100, means 104 for evacuating the material separated in the vessel towards the holding tank 102, and means 106 for pressurizing the vessel 100. ;15 More generally, the vessel 100 of the separator 72 can be placed in the interior space delimited by any drum present on the ship 20. ;The vessel 100 is generally cylindrical in shape and has a diameter slightly smaller than that of the cylinder 80 in which it is placed. It has a cylindrical peripheral wall 20 108 which is closed off transversely relative to the axis X-X' by first and second end walls 110, 112. ;The walls 108, 110, 112 delimit on the inside a cavity 114 for separation of the material brought to the surface by the flexible pipe 24. ;25 ;The vessel 100 is fixedly mounted on the platform 60 by way of fixing arms 116. Each arm 116 is attached to an end wall 110, 112 and to the platform 60. ;30 ;The peripheral wall 108 is in the shape of a cylinder of axis X-X'. The rollers 92 of the drum 68 roll on an outer surface of the wall 108 during rotation of the drum 68 about its axis X-X'. ;RECEIVED at IPONZ on 26 September 2011 ;12 ;As is shown in Figure 6, the left-hand end wall 110 has three nozzles 118 for connection to the flexible pipe 24, which nozzles 118 are distributed about the axis X-X'. Each nozzle 118 comprises a head 120 for connection to a flange 54 of an end section of the flexible pipe 24. ;5 ;Each nozzle 118 further comprises a member 122 for injecting the material coming from the pipe 24 into the separation chamber 114. The injection member 122 is bent in the form of a helix towards the wall 108 in order to direct the flow of material from the nozzle 118 tangentially onto the peripheral wall 108 of the vessel 10 100. This avoids damage to the equipment present in the separation chamber 114. ;In the example shown in Figure 6, the left-hand wall 110 comprises three connection nozzles 118, which allows it to be adapted to various positions of the end section 50 of the pipe 24 when the pipe 24 is wound on the drum 68. ;15 ;The left-hand wall 110 further comprises an upper gas evacuation outlet 123 which is connected to the compressor 74. The compressor 74 is thus connected, at the inlet, to the gas evacuation outlet 123 and, at the outlet, to the line for injection of gas into the interior passage 48, as is shown in Figure 2. ;20 ;The right-hand end wall 112 comprises, in its upper portion, an inlet 124 for the injection of pressurized fluid and, in its lower portion, an outlet 126 for the evacuation of material separated in the separator, connected to the holding tank 102 by way of an intermediate pipe 128. ;25 ;The holding tank 102 is arranged on the platform 60. It is intended to be maintained at atmospheric pressure, for the recovery of the solid materials issuing from the separator 72. ;30 The evacuation means 104 comprise an endless screw 130 arranged in the separation chamber 114, and a controllable pressurization valve 132 arranged on the intermediate pipe 128, between the chamber 114 and the holding tank 102. ;RECEIVED at IPONZ on 26 September 2011 ;13 ;The endless screw 130 is placed in a lower portion of the chamber 114 in the vicinity of its bottom. It extends parallel to the axis X-X' and has one end opposite the evacuation outlet 126. ;5 The endless screw 130 is motorized in order to allow a solid and/or liquid material to be conveyed towards the intermediate pipe 128 when the valve 132 is open. ;A plate 130A forming a guide is located above the endless screw 130 in order to guide sediment towards the intermediate pipe 128. ;10 ;The valve 132 is controllable to be open during the evacuation of material from the chamber 114 and to be closed in order to maintain the chamber 114 under pressure during the separation of the material coming from the pipe 42, as will be seen hereinbelow. ;15 ;The pressurization means 106 comprise a source of compressed water 134 connected to the inlet 124. ;The operation of the extraction device 10 according to the invention will now be 20 described. ;Firstly, the flexible pipe 24 is mounted by assembling the various individual sections 50 end to end by way of their fixing flanges 54. ;25 The assembly can be carried out on land or directly on the ship 20. During the assembly, the lines 44, 46 are assembled by connecting end to end the line sections present on an individual section 50. Likewise, the interior passage 48 is continuous between the first point 38 and the second point 40. ;30 Once the pipe 24 has been assembled, or during its assembly, it is wound on the drum 68. To that end, the motorized wheels 96 are activated in order to wind the pipe 24 helically around the outer surface 84, over substantially its entire length. ;RECEIVED at IPONZ on 26 September 2011 ;14 ;During the positioning on the drum 68 of each pair of assembled fixing flanges 54, an opposite pair of wedges 88 is displaced around a periphery of the cylinder 80 in order to make the flanges 54 enter a groove 90 and make the two sections 50 adjacent to the fixing flanges 54 rest on the wedges 88. ;5 ;The pipe 24 is accordingly stored on the ship 20 in a simple and compact manner. It is further ready to be deployed rapidly and at low cost when an operation of mining material is to be carried out. ;10 To that end, the surface apparatus 18 on the ship 20 is placed opposite the region of the bed from which material is to be removed. The bed unit 22 is withdrawn from the wedges of the ship 20 and the lower end of the flexible pipe 24 is connected to the base station 26. ;15 The pipe 24 is engaged through the selective holding clamp 64 on the edge 62 of the ship. ;Then, the bed unit 22 is immersed beneath the water while being held at the lower end 40 of the pipe 24 and by an auxiliary winch 140 mounted on the platform 60. 20 The unit 22 is lowered to the bed 14 by releasing the clamp 64 and gradually unwinding the pipe 24 from the drum 68, and from the winch 140. If necessary, unwinding of the pipe 24 is stopped and the pipe 24 is held in position by tightening the holding clamp 64. ;25 When the excavator vehicle 28 touches the bed 14, the base station 26 is kept away from the bed 14. The flexible pipe 24 is then tightened substantially linearly between the holding clamp 64 and the base station 26. ;In this deployed configuration of the pipe 24, the upper end of the pipe 24 is fixed 30 to a connection nozzle 118. The port 37 inside the flexible tube is connected to the interior passage 48, which opens into the separation chamber 114 of the separator 72. ;RECEIVED at IPONZ on 26 September 2011 ;15 ;The pipe 24 is deployed outwards above the lateral edge 62 of the ship 20 by overlapping the edge 62. It is therefore not necessary to have a ship 20 with a central well for the deployment of the extraction device 10. ;5 Likewise, the functional lines 44 are connected to the control means 76 and to the power supply means 78 on the surface apparatus 18 and to the base station 26 and to the vehicle 28. ;Accordingly, the vehicle 28 and the base station 26 are supplied with power from 10 the surface apparatus 18 through the lines 44 in order to drive the vehicle 28 and activate the removal means 34. Likewise, the displacement of the vehicle 28 and the movement of the removal means 34 by the control means 76 are controlled from the surface apparatus 18 through the lines 44. ;15 Furthermore, the inlet of the compressor 74 is connected to the gas evacuation outlet of the vessel 100, and the outlet of the compressor 74 is connected to the gas injection line 46. ;In order to start mining of the material from the bed 14, the control means 76 send 20 an activation signal to the base station 26 and to the vehicle 28 in order to supply power to the removal means 34 and control the displacement of the vehicle 28 on the bed 14. ;The removal means 34 remove the material from the bed and convey it to the 25 entry of the port 37. ;The pumping means present on the base station 26 start raising the material, composed of a liquid/solid mixture, towards the apparatus 18. ;30 In order to facilitate the raising of the material towards the surface apparatus 18, the compressor 74 is started. The compressor 74 then injects gas, for example compressed air at about 100 bar, into the passage 48 at an injection point 142 situated between the first point 38 and the second point 40. ;RECEIVED at IPONZ on 26 September 2011 ;16 ;The injection point 142 is, for example, situated at a depth of about 1000 m in order to enable the column of material circulating in the passage 48 above the injection point 142 to be made lighter and the material thus to be carried towards 5 the surface apparatus 18. ;A continuous flow of removed material is then established between the removal means 34 and the separation chamber 114 through, in succession, the port 37, the passage 48 and the connection nozzle 118. The mixture collected in the region of 10 the nozzle 118 is composed of liquid, solid and gas circulating at a suitable speed of preferably from 15 to 20 m per second. ;In this configuration, the outlet valve 132 of the separator 72 is kept closed, so that the pressure in the separation chamber 114 is greater than atmospheric pressure. 15 The pressure is, for example, from 15 to 30 bar. ;The liquid/solid/gas mixture then enters the chamber 114, where it undergoes separation by gravity. ;20 The gas collected in the upper portion of the chamber 114 is re-injected into the compressor 74 through the outlet 123, which limits the energy loss and the size of the compressor 74. ;The solid material accumulates in the bottom of the chamber 114 around the 25 endless screw 130. When the chamber 114 has to be emptied, the valve 132 is opened and the endless screw 130 is activated in order to evacuate the solid material and some of the liquid through the intermediate pipe 128 to the holding tank 102. In order to maintain a pressure of from 15 to 30 bar in the chamber 114, pressurized water is injected through the inlet 124. ;30 ;When the extraction operation is finished, the bed unit 22 is brought back to the surface by winding the pipe 24 around the drum 68 as described above. ;RECEIVED at IPONZ on 26 September 2011 ;17 ;In a variant, the flexible pipe 24 does not have a power transfer line. An umbilical comprising power lines is lowered simultaneously with the flexible pipe 24 in order to supply the excavator vehicle 28 with power. ;5 In a variant which is not shown, the separation chamber is not maintained under pressure during the discharge of material therefrom. In this case, the size of the compressor 74 is greater, and the injection point is situated lower than in the first device 10 according to the invention. ;10 In another variant, the bed unit does not have a base station 26. The flexible link 30 is connected directly to the flexible pipe 24 by way of an adapter piece. ;Part of a second device 210 according to the invention is shown in Figure 8. Unlike the first device 10, the second device 210 comprises, in the deployed configuration ;15 of the flexible pipe 24, a plurality of units 212 for injecting a liquid under pressure into the circulation passage 48 in order to convey the material towards the surface apparatus 18. ;Each injection unit 212 is, for example, mounted between two fixing flanges 54A, ;20 54B of two adjacent sections 50 during deployment of the flexible pipe 24 from the drum 68. The units 212 are, for example, mounted by operators located on the mounting station 63, and the units 212 are held on the flanges 54A, 54B by fixing rings 213. ;25 Each pumping unit 212 accordingly comprises a sleeve 214 delimiting, on the inside, part of the circulation passage 48, a nozzle 216 for removing water from the body of water 12 and distributing it into the passage 48, and a hydraulic turbine 218 for pumping and pressurizing the injected water. ;30 The nozzle 216 delimits a generally transverse port 230 which opens on the outside into the body of water 12 through a strainer 222 and is inclined axially upwards into the passage 48. ;RECEIVED at IPONZ on 26 September 2011 ;18 ;The hydraulic turbine 218 is fixed to the sleeve 24. In the example shown in Figure 8, the turbine 218 is supplied hydraulically through a connection piece 224 on a functional line 44A coming from the apparatus 18. The connection piece 224 opens into the body of water 12 through an outlet 226 after it has passed into the 5 turbine 218, without being connected to a lower portion of the line 44A situated in the section 50 beneath the sleeve 214. ;The sleeve 214 further delimits at least one section 228 of another functional line 44B which is to supply another pumping unit situated beneath the unit 212. ;10 ;During operation, the turbine 218 is supplied with hydraulic fluid from the surface apparatus 18 via the line 44A and the connection piece 224. Supplying of the turbine 118 causes water to be drawn into the port 230 through the strainer 222, followed by pressurization of the water drawn into the port 230. The pressurized 15 water so obtained is injected into the passage 48 in order to carry the material circulating in the passage 48 towards the surface apparatus 18. ;The presence of injection units 212 distributed along the flexible pipe 24 allows the pump to be omitted from the base station 26 and the injection of transport gas into 20 the passage 48 to be omitted. This simplifies especially the surface apparatus 18, which does not have a compressor. ;In a variant, the turbines 218 are supplied with power by a functional line located in the flexible pipe or by an external umbilical. ;25 ;The third device 250 shown in Figures 9 and 10 differs from the second device 210 in that the injection units 212 do not have hydraulic turbines. The liquid under pressure which is to be injected into the circulation passage 48 is stored in a pressurized reservoir arranged on the ship 20 in the surface apparatus 18. ;30 ;Each unit 212 comprises an annular distributor 252 of liquid under pressure, which is arranged around the sleeve 214. The annular distributor 252 delimits a peripheral cavity 254, of toric shape around the axis of the pipe 24. ;RECEIVED at IPONZ on 26 September 2011 ;19 ;The cavity 254 is connected to the reservoir of liquid under pressure at the surface by way of the functional line 44A. It is connected to the passage 48 by four radial injection orifices 256 distributed angularly around the axis of the pipe 24, as shown 5 in Figure 10. ;Each injection orifice 256 opens axially upwards into the passage 48. ;During operation, the water under pressure is brought into the cavity 254 of the 10 distributor 252 from the reservoir of the surface apparatus 18, through the functional line 44A. It is distributed uniformly in the cavity 254 in order to be injected through each orifice 256. ;More generally, such pumping units may be used on a flexible pipe of any 15 installation. ;A fourth device 310 according to the invention is shown in Figure 11. Unlike the first device 10, the removal means 34 comprise an excavation crane 312 which can be deployed and operated from the surface apparatus 18 independently of the 20 flexible pipe 24. ;The bed unit 22 further comprises means 314 for receiving and treating material, which means are positioned on the bed 14 of the body of water 12 and are connected to the flexible pipe 24. ;25 ;The crane 312 comprises jaws 316 for removing material from the bed 14, and a cable 318 for deployment of the jaws 316 in order to lower the jaws 316 from the ship 20 towards the bed 14. ;30 The receiving means 314 comprise an adjustable support 320 which is positioned on the bed 14, and a grinder/crusher 322 mounted in the support 320. ;RECEIVED at IPONZ on 26 September 2011 ;20 ;The support 320 delimits a funnel 324 for receiving the material removed by the jaws 316, which funnel is open to the top and opens opposite the grinder/crusher 322. The support 320 can be deployed from the surface apparatus 18 towards the bed 14 by deployment means (not shown) which are independent of the crane 5 312. ;The support 320 has adjustable feet in order to keep it substantially horizontal and fixed on the bed 14. ;10 The support 320 and the grinder/crusher 322 are connected to a free end of the flexible link 30 in order to connect the flexible tube 36 to the grinder/crusher 322. ;In order to carry out an operation of removing material, the receiving means 314 and the flexible pipe 24 are lowered towards the bed 14, until the support 320 is 15 positioned on the bed 14 and is immobilized on the bed 14. ;The crane 312 is then manoeuvred in order to bring the removal jaws 316 in contact with the bed 14. The jaws 316 are then activated in order to remove material from the bed 14, and then moved opposite the funnel 324 in order to 20 deposit the material removed by the jaws 316 in the grinder/crusher 322. ;The material treated in the grinder/crusher 322 is then raised to the surface apparatus 18 through the flexible tube 36 and the flexible pipe 24, as described hereinbefore. ;25 ;Received at IPONZ 7 October 2011 *

Claims

21 CLAIMS

1. Device for extraction of a material from the bed of a body of water, of the type 5 comprising: - a surface apparatus which is to extend at least partially above the surface of the body of water; - a bed unit comprising means for removing material from the bed of the body of water; 10 - a material transport pipe which connects a first point situated on the surface apparatus to a second point situated on the bed unit, the transport pipe delimiting at least one passage for circulation of material; - at least one functional line which is flexible over substantially its entire length and which connects the bed unit to the surface apparatus, the functional line being 15 capable of transmitting electric or hydraulic power, information or a fluid between the surface apparatus and the bed unit, the surface apparatus comprising at least one drum around which the or each functional line is wound; wherein the transport pipe is flexible over substantially its entire length, the or each functional line being arranged around the transport pipe to form a flexible pipe, the 20 transport pipe and the or each functional line being deployable conjointly between a rest configuration, in which they are wound on the winding drum, and a configuration in which they are deployed towards the bed of the body of water.

2. Device according to claim 1, characterized in that the flexible pipe comprises 25 an annular layer surrounding the transport pipe, the layer delimiting longitudinal passages for receiving the or each functional line, into which passages the or each functional line is inserted.

3. Device according to either claim 1 or claim 2, characterized in that the 30 surface apparatus comprises a ship, the drum being mounted for rotation on a platform of the ship. Received at IPONZ 7 October 2011 22

4. Device according to claim 3, characterized in that the ship delimits a lateral edge, the flexible pipe being deployed transversely towards the outside of the ship opposite the lateral edge.

5 5. Device according to any one of the preceding claims, characterized in that the flexible pipe comprises a plurality of sections assembled end to end.

6. Device according to claim 5, characterized in that each section comprises a tubular portion and, at each end of the tubular portion, a flange for connection to an 10 adjacent section, the transversis dimension of the flange being greater than that of the central portion, and in that the drum delimits: - a support surface for the pipe, and - at least one groove for receiving the connection flanges of at least two adjacent 15 sections, displaceable around the support surface, said flanges being inserted into the groove when the flexible pipe is in its wound configuration.

7. Device according to any one of the preceding claims, characterized in that the bed unit comprises an extractor vehicle equipped with removal means. 20

8. Device according to claim 7, characterized in that the bed unit comprises a base, the extractor vehicle being connected to the base by a flexible link delimiting a material transport port, the extractor vehicle comprising means for displacement on the bed and the removal means for removing material, the port opening into the 25 circulation passage and opposite the removal means.

9. Device according to any one of the preceding claims, characterized in that the surface apparatus comprises a gas/liquid/solid separator which delimits a separation chamber connected to the circulation passage. 30

10. Device according to claim 9, characterized in that the separation chamber comprises: - an outlet for evacuation of a solid separated in the separation chamber, and Received at IPONZ 7 October 2011 23 - a valve for closing off the evacuation outlet, which valve is capable of being controlled in order to maintain the separation chamber at a pressure greater than atmospheric pressure during the discharge of material issuing from the circulation passage into the separation chamber. 5

11. Device according to claim 9 or 10, characterized in that the flexible pipe comprises at least one line for the injection of gas for carrying the material, the gas injection line opening into the circulation passage away from the surface apparatus, the surface apparatus comprising a compressor which has an inlet connected to the 10 separator and an outlet connected to the gas injection line.

12. Device according to any one of the preceding claims, characterized in that, in the deployed configuration, the flexible pipe comprises at least one unit for injecting liquid under pressure into the circulation passage, the liquid under pressure being 15 capable of carrying the material towards the surface apparatus.

13. Device according to any one of claims 9 to 11, characterized in that the winding drum delimits an interior space, the separation chamber being arranged at least partially in the interior space. 20

14. Device according to any one of the preceding claims, characterized in that the bed unit comprises a material collection support, connected to the flexible pipe, the collection support being intended to be placed on the bed in order to collect the material removed by the removal means, the removal means being deployable from 25 the surface apparatus independently of the collection support.

15. Method of extracting a material from the bed of a body of water with the aid of a device according to any one of the preceding claims, the method being of the type comprising the following steps: 30 - positioning the surface apparatus opposite a region of the bed from which material is to be extracted, the flexible pipe being wound around the winding drum in its rest configuration; Received at IPONZ 7 October 2011 24 - deploying the flexible pipe into its deployed configuration by unwinding it from the winding drum in order to immerse it conjointly with the bed unit until the removal means reach said region of the bed; - extracting the material from said region of the bed by the removal means, and 5 conveying the extracted material towards the surface apparatus through the circulation passage of the transport pipe.

16. Device according to claim 1, substantially as herein described with reference to any embodiment disclosed. 10

17. Device for extraction of a material from the bed of a body of water, substantially as herein described with reference to any embodiment shown in the accompanying drawings. 15

18. Method according to claim 15, substantially as herein described with reference to any embodiment disclosed.