FR2936217A1 - Modular semi-submersible barge i.e. catamaran, for performing boring operation in e.g. sea, has floaters constituted by box assemblies comprising rows of boxes assembled with respect to each other by disconnectable connections - Google Patents

Abstract

The barge has two elongated rectangular shaped floaters (1, 2) partially immersed and parallely directed with respect to each other. A metallic frame (20) is integrated with the floaters by a base of the frame, where the frame horizontally extends and supports a lower bridge (21) and an upper bridge (22) of the barge. The floaters are constituted by modular cylindrical box assemblies (1a, 1b, 2a-2d) comprising rows of modular cylindrical boxes (10) assembled with respect to each other by disconnectable connections. The box assemblies define rectangular surfaces.

Description

The present invention relates to a modular semi-submersible drill barge.

Drilling operations at sea or in lacustrine areas require significant resources (derrick, cranes, mud factories ...) which find their place on a floating means, a ship or a self-propelled barge or not. When these drilling operations are to be carried out at open sea, the installation of a ship or a barge of drilling is done naturally by sea; if the drilling requires a specific floating means, many seaside shipyards can build it without difficulty. A particular problem arises when the drilling operation is to be carried out in a closed sea or a lacustrine zone, which may nevertheless be subject to large swells. In fact, given their isolation from the general maritime traffic, these areas generally do not have sufficient infrastructure such as a shipyard to build the vessel or the barge necessary for drilling, and it is not possible to put in place such an infrastructure for this purpose alone. All drilling equipment, including the barge, must then be delivered as spare parts to a seaport and transported by land, rail or truck to an assembly area at the closed seaside or lake area. . This represents a significant logistical constraint that may lead to seeking to minimize the size of the floating means to be constructed. This solution poses other problems: on the one hand a floating medium of small size and / or close to the water level will be more sensitive to swell, which can penalize drilling operations, on the other hand the bridge a means of floating too low on the water will be frequently swept by the swell which on the one hand is dangerous for the personnel, on the other hand may cause unacceptable pollution by hydrocarbons from the closed sea or the lacustrine zone .

Once the drilling is completed and put into operation, the opposite problem arises, namely the dismantling and the return transport of the drilling equipment.

There is therefore a need for a drill barge that can be easily assembled and disassembled in situ, without requiring a manufacturing plant, but without sacrificing the size of the barge and in particular the height of the bridges above the water level. to be as little as possible subject to the effects of the swell. To this end, the invention proposes a semi-submersible barge in the form of a catamaran comprising: two partially immersed floats oriented parallel to each other and spaced apart from each other, a cross-linked framework emerging which extends horizontally and supports the bridges of said barge, said frame being secured to the floats by its base, each float being constituted by at least one set of modular boxes, assembled to each other by disconnectable connections.

Advantageously, each float comprises four sets of modular boxes: a first set, fully immersed in use, of elongate shape and having two ends. disposed substantially horizontally, - a second and a third sets of modular boxes resting on the first set in the vicinity of a respective end of the first set and of which they are integral, and a fourth set of modular boxes resting on the first set adjacent to the adjacent to its middle part and of which it is integral, the base of the reticulated framework resting on the second, third and fourth sets of modular boxes.

The buoyancy of the barge is mainly provided by the first sets of caissons which are totally immersed and therefore relatively subtracted from the effects of the waves. On these first sets of caissons and in the vicinity of each end, rest the second and third sets of boxes that play a dual role: being partially immersed, they provide additional buoyancy, but being smaller in size than the first sets, their floatation surface is weak and they are therefore not very sensitive to the effects of waves, - they ensure a transmission of forces between the base of the emerged frame and the first sets of boxes.

Advantageously, the sets of modular boxes define rectangular surfaces, the length of the first set being substantially equal to that of the frame.

The modular boxes are identical in shape, making it easier to assemble boxes in situ. Moreover, their largest dimension less than 15 meters makes it possible to predict their transport by terrestrial means such as trucks or railroad tracks. The invention provides at least two forms of boxes: a cylindrical shape with hexagonal section, a parallelepiped shape.

The modular box assemblies comprise rows of boxes arranged in their greatest length and assembled by a vertical face, said rows being assembled side by side by a vertical lateral face of the boxes in at least one horizontal layer so that the boxes are arranged in staggered rows.

Although it is conceivable that the sets of boxes, including the first set, comprises several layers of boxes superimposed on one another, for example for barges large displacement, in a preferred variant, the sets of modular boxes each comprise only one layer of rows of boxes. In this variant, the first sets of caissons comprise four rows of caissons assembled side by side, and the second. third and fourth sets of boxes each have three rows of boxes assembled side by side. For structural reasons, in particular their resistance to pressure, the boxes are compartmentalized into cells. These cells do not communicate with each other and, in order to ensure the buoyancy and ballasting of the platform, can be of one of three types: closed and permanently empty, provided with an opening and permanently full of water, provided with an opening communicating with '.'eau water and an air supply so as to be ballastable by all or nothing by air flush.30 The ballastable cells comprise for example an opening communicating permanently with the water. water and downward and an air supply, so as to be able to operate a ballasting by flushing. This avoids the presence of any moving part (valve, valve, seal ...) on the boxes themselves, facilitating their manufacture and maintenance. The modular design of the floats means that all-or-nothing cell-by-cell hunting is possible, whereas it would not be possible on a large-volume ballast. The ballast of the barge is thus controlled by quantum of one cell at a time and not by the regulation of a liquid level in a large volume ballast.

The ballasting means make it possible in particular to keep the draft of the barge constant despite the variable loads, and to ensure that, in use, the air-water interface always passes through the second, third and fourth sets of caissons. , which is the ideal position with respect to the wave holding of the barge.

In order to allow the barge to be transported in parts and assembled and disassembled in situ, the reticulated framework is composed of beams assembled to each other by disconnectable connecting means. In addition, each box is provided on each face intended to be assembled with one side of an adjacent box, disconnectable connecting means cooperating with the connecting means of said adjacent face, for the purpose of assembly and disassembly said sets of boxes.

Advantageously, said disconnectable connection means provided on the face of a box comprise: on the vertical face of a box, at least one first sleeve oriented vertically, 2936217 -6 on the vertical face of the adjacent box, at least one second sleeve also vertically oriented and coming in line with said first sleeve when the two boxes are brought together to be assembled, a pin intended to take place in said sleeves, so as to secure the two boxes.

Advantageously, the spindle may comprise at its tip a flexible part which disappears when it is put in place but which prevents its return movement, and at its head an enlarged part which does not penetrate inside the upper sheath 10 and locks the pin in place.

Alternatively, said disconnectable connection means comprise: at least one male hook-shaped piece which extends on the face of a box, at least one female piece which extends on the face of the adjacent box, each female part being adapted to cooperate with a male part disposed on the face of an adjacent box, a locking means of the male part inside the female part.

This leads to a barge design of relatively large size but which can be assembled and disassembled in modules by means of disconnectable connection means, and therefore easily transportable by terrestrial means.

The invention will be better understood on reading the description which follows and in the light of the appended figures in which: FIG. 1 is a perspective view of the barge according to the invention, FIG. 2 is a diagrammatic view of A section of the barge according to the invention in a transverse plane A, Figure 3 is a schematic view of a section of the barge according to the invention along a longitudinal plane B, 2936217 -7 Figure 4 is a schematic view Fig. 5 is a perspective view of a box, Fig. 5A is a schematic perspective view of two boxes having assembly means on their respective transverse faces. FIG. 6 is a schematic plan view of the first barge float box assemblies; FIG. 6A is a schematic diagram of the air circuit of a ballastable cell; FIG. 7 is a schematic perspective view of two cais Figure 8 is a schematic perspective view of a disconnectable link means, Figures 8A-8F being schematic cross-sectional views of a mounting sequence of these disconnectable link means. .

As illustrated in FIGS. 1 to 3, the semi-submersible barge according to the invention comprises two elongated rectangular shaped floats 1 and 2 on which a metal frame 20 rests. This frame supports a lower deck 21 and an upper deck 22 on which The drilling rigs and drilling floor 23 are raised above the upper deck 22. The bridges 21 and 22 have a rectangular shape, the longest of which is parallel to the direction of the floats. In this same direction, the frame 20 and the bridges 21 and 22 have an indentation about a quarter of their length and half their width intended to receive the wells. The drilling floor 23, on which the drilling apparatus 24 rests, overhangs this indentation. The barge also includes at least one crane 25 for handling drilling equipment. In order to hold it in place, one of the bridges of the barge, for example the deck 21, has a double winch at each corner, for example 4a and 4b, on which are wound cables or chains which connect the barge with eight anchors placed on the bottom. The frame 9 is a cross-linked framework, that is to say composed of beams delimiting parallelepiped-shaped cells. It consists of three main types of elements: four large rigid structures, called longitudinal trusses, 5a to 5d, arranged in its greatest length and having at their base three vertical extensions, one in the vicinity of each end, for example 5d1 and 5d3, and another in their middle part, for example 10 5d2, also made of metal frame, these vertical extensions bearing on the floats 1 and 2, two farms resting on each float, five transverse farms, 6a to 6e, secured to the vicinity of their end of the four longitudinal trusses, also having at their base vertical extensions at their end, for example 6a1, resting on the floats 1 and 2, four transverse light structures, 7a to 7d, which complete the transverse mesh of the frame, and may not rest on the floats 1 and 2. 20 The frame 9 is designed in a modular way and assem by disconnectable means.

Floats 1 and 2 are each composed of four sets of hollow modular boxes: a first set la (or 2a) of elongate shape, of length substantially equal to that of frame 20, on which a second set lb (resp 2b) and a third set ld (respectively 2d) of caissons of smaller size, assembled on the first set la (or 2a) in the vicinity of its respective ends. 2936217 -9 and on which also rests a fourth set 1c (respectively 2c) smaller boxes, assembled on the first set la (or 2a) in the vicinity of its middle part. The vertical extensions of the longitudinal and transverse trusses of the frame are based on the second, third and fourth sets of caissons of the floats. The floats 1 and 2 are therefore also of entirely modular design. The assembly constituted by the frame 9 and the floats 1 and 2 has a longitudinal axis of symmetry X-X '.

The buoyancy of the barge is provided by the caissons that make up the floats. For good resistance to the swell of the barge in use, the first sets of boxes are completely immersed, the air-water interface 8 passing through the second, third and fourth sets. During transits, the barge can be unballasted to reduce drag, the air-water interface then being located at the top of the first sets of boxes.

In the particular embodiment illustrated in FIG. 5, the boxes 10 are of cylindrical shape with a regular hexagonal base, comprising six lateral faces 11a to 11f and two transverse faces 12a and 12b (not visible), but they could also be another form for assembling them easily, for example parallelepiped. Their length is between 6 and 15 m, so as to be easily transportable by land, truck or railway. Preferably the sets of boxes 1a, 1b, 1c, 1d, 2a, 2b, 2c and 2d consist of a combination of boxes of six meters and boxes of twelve meters. The first sets of caissons comprise rows of caissons constituted by arranging the caissons horizontally in their greatest length and assembling them by their transverse faces 12a and 12b; for example, these transverse faces each comprise at least one male part and one female part, some cooperating with the others when the boxes are approached from one another so as to prevent the slipping of a facing each other, as illustrated in FIG. 5A. These rows are themselves assembled side by side by the vertical side faces 5 of the boxes, so as to form a layer of boxes assembled to each other. When the boxes have a hexagonal section, they are oriented with two vertical side faces 11a and 1l d, an upper edge 13a and another lower edge 13b, and they are assembled by these vertical side faces 1 10 and 11d. For better rigidity of these first sets, the rows are assembled so that the boxes are arranged staggered, as shown in Figure 6; to keep the rectangular shape of these first sets, they must be made of boxes of different lengths, for example 12 m and 6 m as indicated above. In the embodiment illustrated in FIG. 6, the first assemblies comprise four rows SB1, SB2, SB3, SB4 and PS1, PS2, PS3, PS4 of caissons, each row comprising five caissons 10 of twelve meters or a combination of caissons. six meters 100 and caissons twelve meters 10 so as to reach the length of 60 meters. The second and third sets are made in the same way as the first set, but they are shorter in length. To improve the rigidity of the floats, each box of the second, third and fourth sets of boxes is based on four adjacent boxes of a first box assembly and, when the boxes have a hexagonal base, intermesh with the boxes of the first sets , as illustrated in Figure 1.

For structural reasons and in particular to withstand the pressure, the boxes 30 are compartmentalized in cells, these cells not communicating with each other. In a preferred embodiment, a box 10 of twelve meters (or six meters in length) is divided into six cells 101, 102, 103, 104, 105, 106 (or three cells 101, 102, 103) two meters long in the axial direction and a volume of about 20 m3, as illustrated in Figure 6.

The cells of the caissons of the first sets 1a and 2a can be of three types: either completely closed, that is to say containing air, or containing water, for example provided with an opening oriented towards the bottom, in permanent communication with the water, 10 is provided with an opening 19 downwards, in permanent communication with the water, and a supply of compressed air, for example a compressed air reservoir 17, so as to be able to contain water, or to contain air, that is to say to carry out a ballast by all or nothing by air flush. To re-ballast, it is sufficient to put the cell in communication with the atmosphere through a bypass 18 of the air supply line of the cell, until it is again filled with water, as illustrated in FIG. 6A for a ballastable type cell. The caissons of the second, third and fourth sets are all closed and contain air. In this way, the boxes have no moving part (valve, seal ...) or level monitoring device in the cells, which simplifies their manufacture and construction of the barge. The distribution of the cells of the three types within the first sets 1a and 2a is made in such a way as: - to distribute the stresses: two cells of the same type are never side by side but adjacent at the most by a stop, to ensure the buoyancy of the barge, 30 to adjust the draft of the barge: the ballastable cells are necessary and sufficient number to reduce the draft during barge transits and, in use, to maintain the air-water interface at the second, third and fourth sets of boxes to balance the variable loads: the ballast cells are arranged in the first sets of boxes to balance the variable loads of the barge, estimated in the embodiment shown in Figures 1 to 6 to 1500 tonnes, or about 75 cells of 20 m3; these variable loads are not necessarily distributed symmetrically with respect to the longitudinal axis X-X 'of the barge, the number of cells of each type may be different from a first set to another.

The boxes are assembled together by means of disconnectable connection means that can take different forms. In a first variant illustrated in FIG. 7, an attachment assembly 40 comprises, on the vertical face 31 of a box 30, a sheath 32 oriented vertically, and on the vertical face 34 of the adjacent box 33, an identical sheath 35 but located below, and a pin 36. To secure the 20 boxes 30 and 33, is brought two vertical faces 31 and 34 so that the sleeves 32 and 35 are located vertically and inserted from top to bottom in these sleeves a pin 36. The pin 36 may comprise a head 37 which is pressed against the upper sheath 32 so as to stop its progression. The pin 36 may also comprise at its base a resilient portion 38, for example a spring blade, which disappears when it is put in place but which is released after the crossing of each sleeve, in particular the lower sleeve 35, of way to avoid unintentional extraction of the spindle, for example under the effect of vibrations. In order to facilitate insertion of the pin 36, the sleeves 32 and 35 may have a slightly flared top opening. In such a fastener assembly, of course, there may be more than two sleeves per fastener assembly 40, provided that they are all arranged in alignment with one another. For example, the face 31 of the box 30 may comprise two sleeves 32A and 32B (not shown), the sheath 35 of the face 34 then being located between the sleeves 32A and 32B. It can of course exist several sets of attachment 40 between two boxes. In a variant of this method of attachment, the sleeves are oriented horizontally and no longer vertically, the pin 36 then being inserted horizontally. In another variant illustrated in FIGS. 8 and 8A to 8F, an attachment assembly 50 has two parts 51 and 52 fitting one into the other, and a key 53 blocking the two parts in the nested position. The cross section of the workpiece 51 has a hook shape with a male portion 51a which extends vertically on the vertical face of a box (not shown). The female part 52, which extends vertically on the face 34 of the adjacent box, is substantially the same length as the male part 51. Its section has a recess 56 formed of an inclined surface 56a with respect to the face 34 of the box and a surface 56b substantially orthogonal to the face 34 of the box. In the recess of the recess 56 is a rod 57, held at each end by two cheeks 54a and 54b orthogonal to the face 34 of the box which delimit the female part 52. The cheeks 54a and 54b each comprise a through opening 55a and 55b, whose section is identical to that of the key 53, for example triangular. When assembling the male 51 and female 52 pieces, at first the male portion 51a of the piece 51 enters the recess 56 between the cheeks 54a and 54b by sliding on the inclined surface 56a, until this male part comes up against the orthogonal surface 56b and that the hollow of the hook abuts on the rod 57. In a second step, the key 53 is introduced into the openings 55a and 55b of the cheeks 54a and 54b until the head 53a of the key 53 abuts against the upper cheek 54a, so as to prohibit any return back of the male part 51.

In an alternative embodiment of this embodiment, it is evident that the section of the female piece 52 may have a hook shape reproducing the outer shape of the piece 51, the important thing being that the cheeks 54a and 54b are preserved with their openings 55a and 55b and the key 53.

Claims (17)

Revendications1. Semi-submersible barge in the form of a catamaran comprising: two floats (1, 2) partially immersed parallel to each other and spaced from each other, a cross-linked framework (20) emerging which extends horizontally and supports at least one bridge (21, 22) of said barge, said frame being secured to the floats by its base, characterized in that said floats (1, 2) are constituted by at least one set (la, lb, 2a, 2b, 2c, 2d) of modular boxes (10), assembled to each other by disconnectable links. 2. semi-submersible barge according to claim 1, characterized in that each float (1, 2) comprises four sets of modular boxes, a first set (2a), fully immersed in use, elongated and having two ends, disposed substantially horizontally, a second (2b) and a third (2d) sets of modular boxes, resting on the first set (2a) in the vicinity of a respective end of said first set and of which they are integral, a fourth set (2c) of modular caissons, resting on the first set in the vicinity of its median portion and which they are secured, the base of the crosslinked framework (20) resting on said second, third and fourth (2b, 2d, 2c) set of modular boxes. 3. semi-submersible barge according to claim 2, characterized in that said sets (la, lb, 2a, 2b, 2c, 2d) of modular boxes define rectangular surfaces, the length of said first set (la, 2a) being substantially equal to that of said frame. 2936217 -16- 4. semi-submersible barge according to claim 3, characterized in that said boxes (10) are of identical shape, their largest dimension being less than 15 meters so as to be transported by a land transport means. 5. semi-submersible barge according to claim 4, characterized in that said boxes (10) are of cylindrical shape with hexagonal section. 10 6. semi-submersible barge according to claim 4, characterized in that said boxes (10) are of parallelepiped shape. 7. Semi-submersible barge according to any one of the preceding claims, characterized in that said sets (la, lb, 2a, 2b, 2c, 2d) of modular boxes are comprise: rows of boxes (10) arranged in their largest length and assembled by their vertical faces (12a), said rows being assembled side by side by the vertical side faces (1 la, 20 11d) of the boxes in at least one horizontal layer, the boxes being arranged in staggered rows. 8. semi-submersible barge according to claim 7, characterized in that said sets (la, lb, 2a, 2b, 2c, 2d) of modular boxes each comprise a single layer of rows of boxes. 9. semi-submersible barge according to claim 8, characterized in that said first sets (la, 2a) of boxes comprise four rows of boxes (PS1, PS2, PS3, PS4, SB1, SB2, SB3, SB4) assembled side side and said second, third and fourth sets (2b, 2d, 2d) of boxes each comprise three rows of boxes assembled side by side. 10. Semi-submersible barge according to claim 9, characterized in that each box of the second, third and fourth sets (2b, 2d, 2c) of boxes is based on four adjacent boxes of a first set of boxes (la, 2a). ). 11. semi-submersible barge according to any one of the preceding claims, characterized in that said boxes (10) are compartmentalized in cells (101, 102, 103, 104, 105, 106) not communicating with each other. 12. Semi-submersible barge according to claim 11, characterized in that the cells (101, 102, 103, 104, 105, 106) of the first sets (la, 2a) of boxes can be of one of three types. following: closed and permanently empty, open and permanently full of water, provided with an opening communicating with the water and an air supply so as to be ballastable by all or nothing by air flushing . 13. Semi-submersible barge according to claim 12, characterized in that the cells (101, 102, 103, 104, 105, 106) are arranged within the first sets (la, 2a) of boxes so that two cells of the same type are only adjacent to one another at a stop. 14. semi-submersible barge according to any one of the preceding claims, characterized in that said crosslinked framework (20) is composed of beams 30 joined to each other by disconnectable connection means. 2936217 - 18 - 15. Semi-submersible barge according to any one of the preceding claims, characterized in that each box (10) is provided on each face intended to be assembled with one side of an adjacent box, connecting means 5 disconnectable cooperating with the connecting means of said adjacent face, for assembling and disassembling said sets of boxes. 16. Semi-submersible barge according to claim 15, characterized in that said disconnectable connection means comprise: on the face of a box, at least a first sleeve (32) oriented vertically, on the face of the adjacent box, at less a second sleeve (35) also vertically oriented and coming directly above said first sleeve (32) when the two boxes are brought together to be assembled, a pin (37) intended to take place inside said sleeves (32); , 35) so as to secure the two boxes. 17. Semi-submersible barge according to claim 15, characterized in that said disconnectable connecting means comprise: at least one hook-shaped male piece (51) which extends over the face of a box, at least a female part (52) which extends on the face of the adjacent box, each female part being able to cooperate with a male part (51) disposed on the face of an adjacent box, a locking means (53) of the male part inside the female part.