FR3062407A1 - METHOD FOR MOUNTING AN INSTALLATION INTENDED TO BE PLACED IN A WATER EXTENDER - Google Patents

Abstract

The method comprises the following steps: - providing the base (14), having an upper surface (22) and supports (16) projecting above the upper surface (22); - Mounting guide rails (36) on the supports (16); - placing the module (18) to be installed on the base (14) on an upper surface located next to the base (14); - translation of the module (18) on the guide rails (36) to bring it to the base (14); placing the module (18) on the supports (16) so that the supports (16) take up the weight of the module (18); releasing the guide rails (36) relative to the supports (16); - Removal of the guide rails (36) by horizontal displacement facing the upper surface (22) of the base (14).

Description

Holder (s): simplified.

TECHNIP FRANCE Joint stock company

Agent (s): simplified.

CABINET LAVOIX Business corporation

METHOD FOR ASSEMBLING A SYSTEM INTENDED TO BE PLACED IN A BODY OF WATER

FR 3 062 407 - A1

@) The process includes the following steps:

- supply of the base (14), comprising an upper surface (22) and supports (16) projecting above the upper surface (22);

- mounting of guide rails (36) on the supports (16);

- placement of the module (18) intended to be installed on the base (14) on an upper surface located next to the base (14);

- Translation of the module (18) on the guide rails (36) to bring it onto the base (14);

- Installation of the module (18) on the supports (16) so that the supports (16) take up the weight of the module (18);

- release of the guide rails (36) relative to the supports (16);

- Removal of the guide rails (36) by horizontal movement opposite the upper surface (22) of the base (14).

Method for mounting an installation intended to be placed in a body of water

The present invention relates to a method of mounting an installation intended to be placed in a body of water, the installation comprising a base and at least one module placed on the base.

The installation is for example a floating production, storage and unloading unit (designated by the English acronym "FPSO", for "Floating Production Storage and Offloading"), a floating liquefied natural gas unit (designated by l 'English acronym' FLNG 'for' Floating Liquefied Natural Gas') or more generally an offshore unit such as a semi-submersible platform, which can for example be a TLP ('Tension Leg Platform' in English) , an unloading buoy, a floating vertical column or a ship. As a variant, the installation is a fixed rigid structure of the "gravity" type, for example a GBS ("Gravity Based Structure").

Floating units of the aforementioned type generally include a floating hull carrying a large number of items of equipment interconnected with one another. This equipment is, for example, connected to each other by pipes, functional lines, such as power lines, hydraulic transfer lines, and / or information transfer lines.

To manufacture such a unit, it is known to assemble the shell, and to deposit different prefabricated modules on the shell. Once placed on the hull, the modules are interconnected to each other to make the different systems of the installation.

The modules are generally placed on the hull using cranes. Given the capacity of current cranes, this implies a limitation in size and weight of the modules.

Thus, a complete fluid operating system sometimes requires being separated into several modules which must be connected and tested after their assembly on the hull. Such a solution is therefore not satisfactory, since access to each module is more complicated than on land, and possible faults on a module can delay the assembly of other systems and / or the commissioning of the 'installation.

Furthermore, it is known in some cases to load modules on a floating base without using cranes. The floating base is ballasted to be flush with the upper surface of a platform on which the module is placed. Then, the module is transferred to the base, sliding it onto guides which are permanently installed on the floating base.

When the module rests on the guides, it is secured to the base, the guides being held in place.

This last method implies that the depth of water in front of the quay is sufficient to allow, after ballasting, the outcrop mentioned above. Including in this hypothesis, the latter method is not entirely satisfactory. Indeed, the presence of permanent guides on the base unnecessarily weighs down the installation and occupies a significant space on the hull, limiting the number and / or the size of the equipment that can be embarked on the hull.

An object of the invention is therefore to have a method of assembling an installation comprising a base and at least one module placed on the base, the method not requiring large capacity cranes, while being implemented works by non-invasive means on the installation.

To this end, the invention relates to a process of the aforementioned type, characterized by the following steps:

- supply of the base, comprising an upper surface and supports projecting above the upper surface;

- mounting of guide rails on the supports;

- placement of the module intended to be installed on the base on an upper surface located next to the base;

- translation of the module on the guide rails to bring it onto the base;

- placing the module on the supports so that the supports take up the weight of the module;

- release of the guide rails relative to the supports;

- removal of the guide rails by horizontal movement opposite the upper surface of the base.

The method according to the invention may include one or more of the following characteristics, taken alone or in any technically possible combination:

-before the translational step, the lifting of the module by its lower surface using a lifting structure disposed in abutment between the upper surface and the lower surface of the module, to bring the lower surface to the height of the guide rails;

the lifting structure comprises lifting beams placed under the lower surface of the module, the method comprising a step of connecting the lifting beams to the guide rails by connecting beams when the lower surface is at the height of the guide rails ;

- the step of removing the guide rails comprises the horizontal pulling of each guide rail from outside the base;

each guide rail comprises a plurality of successive sections, the removal step comprising the horizontal pulling of at least one section of each guide rail outside the base, then the dismantling of the section located outside from the base;

- The removal step involves the horizontal displacement of the guide rails away from the module, keeping part of the guide rails facing a region of the upper surface located away from the module, the translation d 'an additional module on the guide rails to the region of the upper surface located away from the module, then the installation of the additional module on the supports;

the base carries equipment on the upper surface, the guide rails after mounting being arranged above the equipment, the equipment advantageously comprising a rack of functional lines and / or pipes, the guide rails passing over the rack ;

- the guide rails have a U-shaped cross section opening upwards;

- The base has a longitudinal axis, the guide rails being mounted transversely to the longitudinal axis;

- the guide rails extend over substantially the entire width of the base, the module having a width greater than 90% of the width of the base, taken at the level of the guide rails;

- The base has a longitudinal axis, the guide rails being mounted parallel to the longitudinal axis;

- the base is partially immersed in a body of water along a quay, the module being carried by the quay during the placement step;

- the base has a hull, the hull floating on the body of water during the module translation stage;

the base is placed on the bottom of a body of water or on the ground of a form during the module translation stage, the method then comprising floating the base by deballasting the base, or / and by filling the form to float the installation comprising the base and the module placed on the base;

- the mass of at least one module is greater than 3500 tonnes;

- the lifting stage comprises the progressive mounting of a removable module lifting structure under the lower surface of the module.

The invention will be better understood on reading the description which follows, given solely by way of example, and made with reference to the appended drawings, in which:

- Figure 1 is a front view of the base of a first installation produced by a method according to the invention;

- Figure 2 is a top view of the installation of Figure 1;

- Figure 3 is an elevational view of a mounting assembly for implementing the method according to the invention;

- Figure 4 is a top view of the mounting assembly of Figure 3;

- Figures 5 to 9 illustrate successive stages of implementation of a first method according to the invention;

- Figure 10 is a top view illustrating the positioning of the guide rails, before the introduction of a module on the basis of an installation;

- Figure 11 is a partial sectional view of the installation, before removing the guide rails;

- Figure 12 illustrates a support mounted on the base, intended to carry the guide rails, then the module after removal;

- Figures 13 and 14 are top views illustrating steps of mounting a second installation produced by a method according to the invention;

- Figure 15 is a schematic view of a column of a lifting structure used in the method according to the invention;

- Figure 16 is a schematic top view of the column of Figure 15.

A first installation 10, intended to be placed in a body of water 12, is illustrated diagrammatically by FIGS. 1 and 2.

The installation 10 is intended in particular for the exploitation of fluid, in particular of hydrocarbons such as petroleum and / or natural gas, the fluid being collected at the bottom of the body of water 12 and brought up to the surface of the body of water 12.

The installation 10 is for example a floating production, storage and unloading unit called FPSO ("Floating Production, Storage and Offloading" in English) or a floating unit dedicated to liquefied natural gas called FLNG ("Floating Liquified Natural Gas >> in English), a semi-submersible platform, which can be for example a TLP ("Tension Leg Platform" in English), an unloading buoy, a floating vertical column or a ship. As a variant, the installation 10 is a fixed rigid structure of the "gravity" type, for example a GBS ("Gravity Based Structure").

The water body 12 is for example a lake, a sea or an ocean. The depth of the body of water 12 at the level of the installation 10 is for example between 50 m and 3000 m, or even 4000 m.

Referring to FIG. 1, the installation 10 comprises a base 14 partially immersed in the body of water, the base 14 having supports 16. The installation 10 comprises at least one module 18 placed and fixed on the supports 16 from base 14.

In the example shown in Figures 1 and 2, the base 14 extends along a longitudinal axis A-A 'between an upstream edge 13 and a downstream edge 15. It defines a port side edge 17 and an edge starboard side 19.

It comprises a hull 20 floating in the body of water 12. The base 14 also has an upper surface 22 here forming a bridge, and equipment 24 carried by the upper surface 22.

The base 14 comprises a selective ballasting system 26 capable of adjusting the height of the upper surface 22 relative to the surface of the body of water 12, and capable of keeping the upper surface 22 substantially horizontal, even if the load applied to the upper surface 22 is inhomogeneous and whatever the variation of the tide.

The equipment 24 includes, for example, functional systems such as mechanical equipment (pumps, overhead traveling cranes, monorails, carriages). The equipment 24 further comprises fluid transport lines, or even functional lines, such as electric power transport lines, hydraulic fluid transport lines, and / or information transport lines.

In the example shown in Figures 1, 2, and 11, the equipment 24 comprises at least one longitudinal rack 27, extending along the base 14 passing below each module 18.

The rack 27 contains a plurality of fluid transport lines and / or functional lines intended to connect modules 18 to one another, or a module 18 with equipment located on the base 14.

The supports 16 protrude from the upper surface 22. They have a height, taken with respect to the upper surface 22, greater than that of the equipment 24 present on the surface 22.

With reference to FIG. 12, each support 16 comprises a base 30, and a head 32 for mounting the module 18. In the example shown in FIG. 12, each support 16 also comprises arms 34 intended to carry rails 36 for guiding the module 18, during its installation.

The base 30 is here of polyhedral or frustoconical shape converging upwards.

The head 32 has an upper support plate 38 for the module 18, and advantageously, a passage 40 for inserting a support device 41 for the module 18 placed on the plate 38.

Each arm 34 projects laterally with respect to the base 30. In the example shown in FIG. 12, the support 16 is provided with two lateral arms 34 extending on either side of the base 30.

Each arm 34 is for example removable with respect to the base 30, in order to minimize the space requirement on the installation 10, once the module 18 has been installed.

In the example shown in Figure 2, the installation 10 comprises a plurality of modules 18 arranged adjacent along the axis A-A ’.

In this example, at least one module 18 extends over substantially the entire width of the base 14, in particular over more than 90% of the width of the base 14, taken between the port side edge 17 and the starboard side edge 19.

Each module 18 comprises a plurality of devices preassembled before the installation of the module 18 on the base 14. The devices are for example tanks, reactors, compressors, turbines, columns in addition to systems similar to those defined more high. The modules 18 are each suitable for fulfilling at least one function in the installation 10, for example separating the gas, water and oil and liquefying the natural gas.

At least one module 18 has a mass greater than 3500 tonnes, preventing the module 18 from being put in place by a crane.

As illustrated in FIG. 11, each module 18 has a lower surface 50 intended to be placed opposite the upper surface 22 of the base 14, bearing on the supports 16. Each module 18 also comprises a plurality of wedging pads 52 projecting downwards with respect to the lower surface 50 to rest on the bearing 41 placed on the plate 38.

The assembly method according to the invention is implemented using a positioning assembly 60, illustrated schematically in FIG. 3.

The positioning assembly 60 comprises a site 62 for assembling the module 18, and a loading dock 64 located between the site 62 and a body of water 66 receiving the base 14. The body of water 66 is connected to the body of water 12, to allow the installation 10 to be conveyed by flotation to the body of water 12.

The positioning assembly 60 further comprises a removable lifting structure 68 of the module 18 by its lower surface 50, the guide rails 36 intended to be placed above the base 14 and connecting beams 70 between the lifting structure 68 and guide rails 36.

Referring to Figures 7 to 9, the positioning assembly 60 further comprises a plurality of pads 72 for horizontal displacement of the module 18 on the lifting beams 76, on the connecting beams 70 and on the rails 36, as well that a traction system 74 of the guide rails 36 away from the base 14.

As illustrated in FIG. 3, the removable lifting structure 68 is a lift capable of lifting the lower surface 50 of the module 18 between a low position situated at the level of an upper surface 75 of the platform 64, and high positions in which the module 18 is arranged above and away from the edge of the quay 64, without using a crane above the module 18.

The demountable lifting structure 68 comprises lifting beams 76 carrying the module 18, deployable columns 78, of progressively increasing height during their assembly, the columns 78 carrying the lifting beams 76, and cylinders 79 and 81 of progressive lifting of each column 78 (visible in FIGS. 15 and 16).

In an exemplary embodiment, illustrated by FIG. 15, each column 78 is formed of a succession of pairs of bars 80 and pairs of crosspieces 82, each pair of bars 80 being arranged perpendicular to a pair of crosspieces 82 and carrying the pair of sleepers 82.

The jacks 79, 81 are arranged at the base of the column 78. At least two jacks 79 are suitable for lifting bars 80 in order to allow the sleepers 82 to be inserted under the bars 80.

At least two jacks 81 are suitable for lifting crosspieces 82 to allow bars 80 to be inserted under the crosspieces 82. Thus, each column 78 is gradually assembled in stages to gradually raise the lifting beams 76 and the module 18.

Crossed diagonals 83 (visible in FIG. 3) connect the columns 78 to each other to avoid lateral instability of the assembly under the weight of the module 18 and to stiffen it.

In the example shown in Figures 3 to 10, the guide rails 36 are adapted to extend transversely over the entire width of the base 14. Each guide rail 36 is produced here in one piece. As illustrated in FIG. 10, the positioning assembly 60 comprises a plurality of parallel guide rails 36, here a pair of rails 36, then a triplet of rails 36, then another pair of rails 36.

Each rail 36 is carried by lateral arms 34 of successive supports 16. Each rail 36 is here hollow and has a U-shape open upwards. It defines a central groove 84 for sliding the pads 72. The groove 84 reduces the overall height of the rail 36 and does not alter the presence of the equipment 24 and the rack 27.

In addition, the groove 84 defines two vertical walls which stiffen the bottom of the guide rail 36. This limits the bending of the rail 36 between two supports 16, in particular when the distance separating the supports 16 is greater than 10 m. This allows the rail 36 to be relatively thin, to reduce its size.

The central groove 84 is advantageously provided with a sliding coating, for example made of polyethylene tetrafluoride and internal stops (not shown) spaced apart longitudinally to allow the hooking and the pushing or pulling of the pads 72.

In FIGS. 7 and 8, each shoe 72 comprises a sole 86, a jack 88 for lifting the module 18, carried by the sole 86 and a deployable arm 90 for pushing / pulling the sole 86, suitable for gripping an internal stop in the guide rail 36 for pushing / pulling the sole 86 and longitudinally moving the jack 88 and the module

18.

Each guide rail 36 is removably attached to the successive supports 16. When the guide rail 36 is released from the support 16, it is capable of being towed substantially horizontally, parallel to the upper surface 22 to be removed from the installation. 10.

With reference to FIG. 9, the traction system 74 is capable of pulling each rail 36 horizontally to extract it laterally away from the base 14 and from the module 18, to free the intermediate space between the module 18 and the upper surface

22. The traction system 74 is for example fixed on the lifting structure 68, after the transfer of the module 18 to the base 14. It comprises for example at least one winch.

A first method of mounting the installation 10 according to the invention will now be described.

Initially, each module 18 is assembled on a building site 62 independently of the base 14. The base 14 is brought into a body of water 66 in the vicinity of the platform 64, and is moored to the platform 64, as illustrated in FIG. 4 .

The guide rails 36 are installed on the supports 16 by means of a crane. They are placed on the arms 34 of the successive supports 16.

In this example, they extend transversely over the entire width of the base 14, between the port side edge 17 and the starboard side edge 19.

The lifting structure 68 occupies a low position in which the deployable columns 78 are dismounted and in which the lifting beams 76 are arranged at the level of the upper surface 75 of the platform 64.

The displacement pads 72 are installed under the lower surface 50 of the module 18. The jacks 88 of the displacement pads 72 are then deployed to release the module 18 from its construction struts. Then, the displacement pads 72 are activated, thanks to the arms 90, to move the module 18 in translation, in order to bring it onto the lifting beams 76.

When the module 18 is placed on the lifting beams 76, the lifting structure 68 is moved to its high position, to bring the lifting beams 76 to the same horizontal level as the guide rails 36.

In this example, the deployable columns 78 are gradually assembled from the upper surface 75 to lift the lifting beams 76 and the module 18 away from the upper surface 75.

In the example shown in FIGS. 15 and 16, the jacks 81 are first activated to lift two sleepers 82 located under the lifting beam 76 from a height substantially equal to that of a bar 80. The bars 80 are placed perpendicular to the crosspieces 82, above the jacks 79 and the rigid supports 83B. The rigid supports 83B located just below the bars 80 allow the assembly to rest on the bars 80, if necessary.

The jacks 81 are then retracted, the cross members 82 coming to bear on the bars 80, and the jacks 79 are deployed at a height substantially equal to that of a cross member 82.

The cross members 82 are then placed above the cylinders 81 and the rigid supports 83A perpendicular to the bars 80. The rigid supports 83A located just below the cross members 82 allow the assembly to rest on the cross members 82, if need.

These operations are repeated until the lifting beams 76 reach a height equal to that of the guide rails 36 on the base 14.

Then, as illustrated in FIG. 4, connecting beams 70 are interposed in the intermediate space between the lifting structure 68 and the base 14 placed in a body of water 66. Each connecting beam 70 connects a lifting beam 76 to a guide rail 36.

This being done, the pads 72 are activated to move the module 18 on the rails 36 in horizontal translation from the lifting structure 68 towards the base 14.

In the example shown in the figures, the arms 90 of each shoe 72 are deployed away from the sole 86 in the direction from the platform 64 towards the base 14, to grip a stop. Then, the arms 90 are retracted into the sole 86, causing the sole 86 to slide towards the stop, and the module 18 to move along the axis defined by each guide rail 36.

The selective ballasting system 26 is activated to maintain the base 14 at a constant level relative to the platform 64 during the progression of the module 18 and thus maintain each guide rail 36 aligned with the connecting beam 70 and the lifting beam 76 This must be ensured whatever the level of the tide which causes base 14 to rise or fall, and the position of module 18 when it is transferred to base 14.

The cylinders 88 being active, the lower surface 50 of the module 18 remains above all of the equipment 24 present on the upper surface 22. In addition, the wedging pads 52 pass over the supports 30, without abutting on the supports 30.

When the module 18 reaches the desired position, for example extending over the width of the base 14 from the port side edge 17 to the starboard side edge 19, and the studs 52 are arranged opposite the supports 16, the jacks 88 are deactivated to bring the lower surface 52 of the upper plate 38 closer to the supports 16, via a bearing 41 if necessary.

During this movement, the supports 16 gradually take up the weight of the module 18.

The traction system 74 of the guide rails 36 is then activated from outside the base 14 to make the rails 36, containing the pads 72, slide horizontally under the lower surface 50, and move them away from the base. 14, advantageously on the lifting structure 68. Beforehand, the connecting beam 70 is removed and the ballasting 26 of the shell 20 is activated in order to level the underside of the guide rail 36 with the top of the lifting beam 76.

The intermediate space between the module 18 and the upper surface 22 of the base 14 is freed from the guide rails 36, which eliminates an unnecessary weight of the installation 10 and increases the space available in the installation 10.

The assembly of the module 18 by the method according to the invention is therefore particularly simple and versatile, since it does not require large capacity cranes. It is thus possible to assemble on a base 14 modules 18, prefabricated and pre-tested on a site 62, placed in a body of water 66, even if the site 62 does not have cranes of sufficient capacity to lift a module 18 having excessive weight.

Thanks to the arrangement of the guide rails 36 above the equipment 24 present on the base 14, the module 18 is capable of sweeping the entire width of the base 14 during its installation, which makes it possible, if necessary, to build modules 18 of large width, and to limit the installation time.

The guide rails 36 being removable, they do not contribute to the weight of the installation 10 once the assembly is complete, and they can be used again for the installation of another module 18, or for the assembly of another installation 10.

In the variant illustrated in Figures 13 and 14, each guide rail 36 consists of several successive sections 100 assembled end to end. Each section 100 advantageously has a length greater than or equal to the length of a module 18.

In this example, the guide rails 36 are placed parallel to the longitudinal axis of the base 14. The upstream edge 13 of the base 14 is arranged opposite the platform 64.

During installation of the installation 10, a first module 18 is translated on the guide rails 36, as described above, to its position of installation. Then, the module 18 is placed on the supports 16 by lowering the jacks 88.

Then, the sections 100 of guide rails 36 disposed under the module 18 are extracted by horizontal translation under the module 18 using the traction system 74. The sections 100 of the guide rails 36 having been extracted away from the base 14 are separated from the sections 100 remaining on the base 14, as illustrated in FIG. 14.

At least one section 102 of each guide rail 36 remains opposite a region of the upper surface 22 adjacent to the module 18. Then, an additional module 18 is translated on the guide rails 36 to the region of the surface upper 22 located away from the module 18. The additional module 18 is placed on the supports 16.

The rail sections 102 located under the additional module 18 are then extracted horizontally, as described above.

Alternatively, the base 14 is placed on the bottom of the body of water 66, or in a dry form 67 during the translation step of the module 18 (see FIG. 13). The method then comprises a floating of the base 14 by deballasting or / and filling of the form 67.

Claims (14)

1. - Method for mounting an installation (10) intended to be placed in a body of water (12), the installation (10) comprising a base (14) and at least one module (18) placed on the base (14), the method being characterized by the following steps: - supply of the base (14), comprising an upper surface (22) and supports (16) projecting above the upper surface (22); - mounting of guide rails (36) on the supports (16); - placement of the module (18) intended to be installed on the base (14) on an upper surface (75) located next to the base (14); - Translation of the module (18) on the guide rails (36) to bring it onto the base (14); - Installation of the module (18) on the supports (16) so that the supports (16) take up the weight of the module (18); - release of the guide rails (36) relative to the supports (16); - Removal of the guide rails (36) by horizontal movement opposite the upper surface (22) of the base (14). 2. - Method according to claim 1, comprising, before the translation step, the lifting of the module (18) by its lower surface (50) using a lifting structure (68) disposed in abutment between the upper surface (75 ) and the lower surface (50) of the module (18), to bring the lower surface (50) to the height of the guide rails (36). 3. - Method according to claim 2, wherein the lifting structure (68) comprises lifting beams (76) placed under the lower surface (50) of the module (18), the method comprising a step of connecting the beams lifting (76) to the guide rails (36) by connecting beams (70) when the lower surface (50) is at the height of the guide rails (36). 4. - Method according to any one of the preceding claims, in which the step of removing the guide rails (36) comprises horizontal pulling of each guide rail (36) from outside the base (14). 5. - Method according to claim 4, wherein each guide rail (36) comprises a plurality of successive sections (100), the removal step comprising the horizontal traction of at least one section (100) of each rail guide (36) outside the base (14), then the disassembly of the section (100) located outside the base (14). 6. - Method according to any one of the preceding claims, in which the removal step comprises the horizontal displacement of the guide rails (36) away from the module (18), while maintaining part of the guide rails ( 36) opposite a region of the upper surface (22) located away from the module (18), the translation of an additional module (18) on the guide rails (36) to the region of the upper surface (22) located away from the module (18), then placing the additional module (18) on the supports (16). 7. - Method according to any one of the preceding claims, in which the base (14) carries equipment (24) on the upper surface (22), the guide rails (36) after mounting being arranged above the equipment. (24), the equipment (24) advantageously comprising a rack (27) of functional lines and / or pipes, the guide rails (36) passing over the rack (27). 8. - Method according to claim 7, wherein the guide rails (36) have a U-shaped cross section opening upwards. 9. - Method according to any one of the preceding claims, wherein the base (14) has a longitudinal axis (A-Aj, the guide rails (36) being mounted transversely to the longitudinal axis (A-Aj . 10. - Method according to claim 9, wherein the guide rails (36) extend over substantially the entire width of the base (14), the module (18) having a width greater than 90% of the width of the base (14), taken at the level of the guide rails (36). 11. - Method according to any one of claims 1 to 8, wherein the base (14) has a longitudinal axis (A-Aj, the guide rails (36) being mounted parallel to the longitudinal axis (A-Aj . 12. - Method according to any one of the preceding claims, in which the base (14) is partially immersed in a body of water (66) along a quay (64), the module (18) being carried by the platform (64) during the placement step. 13. - Method according to claim 12, wherein the base (14) comprises a shell (20), the shell (20) floating on the body of water (66) during the step of translation of the module (18) . 14. - Method according to any one of claims 1 to 12, wherein the base (14) is placed on the bottom of a body of water (66) or on the ground of a form (67) during the module translating step (18), the method then comprising floating the base (14) by deballasting the base (14) or / and by filling the form (67) to float the installation (10) comprising the base (14) and the module (18) placed on the base (14).