Marine working platform - partic for operating in deep water

Holder: Idem (7Ï)

74) Agent:

Structure for maritime works, and corresponding implementation.

72) Invention of;

.33) (32) (31

Conventional priori ty:

Sale of bookl ets at IMPRIMERIE NATIONALE, 27, rue de la Convention - PARIS (15^e)

19474

The object of the present invention is a partially removable and partially articulated structure, for maritime works, and its method of implementation.

It is the result of the new juxtaposition of known devices and new organs, which together contribute to equally new equipment, implementation and use.

It relates in particular to platforms intended for carrying out work at sea for depths exceeding 100 meters.

In the current state of the art, there are at least three types of platforms intended for this use.

Some are rigid frames rising above the water and resting on the bottom in which their piles are generally extended by piles.

By construction it leads to considerable dimensions and weights as soon as the depth increases. Their transport and their installation on the site require very powerful mean s. Once assembled, they are pra ctically irremovable.

The others are semi-submersible platforms resting on floats immersed at about twenty meters and connected or not to the bottom by a set of cables. They are sensitive to the effects of swell, wind and currents which give them more or less accentuated movements in all their degrees of freedom, thus limiting the operations that it is possible to carry out from their work floor.

The last type, finally, is presented as a single vertical column provided with a float at mid-height and plunging into the water until a base resting on the bottom, to which it is attached by a joint. ''

It has the disadvantage of adopting under the effect of the elements an average inolination little ororapatible with long-term work, to oscillate around this position and to present below the work floor an articulation and an obstructing base The location of the bottom where the work is to be carried out.

Without the device which is the subject of the invention, it is a mixed structure c omposed of a solid frame with a rigid surface, resting on a hollow base, by means of at least four articulated submerged columns. .

19474 thanks to this di ^ esiticaa ^ d. * taa »share the work space on the seabed is largely clear and fully accessible, on the other hand the work platform, although subject to small displacements due to the elements , always remains parallel to the seabed and finally, thanks to the continuity of the connection between the seabed and the floor of the structure, it is easy to provide pipe connections capable, for example, of transporting the production of pressurized oil wells.

In addition, as will be seen in the description below, the installation of this structure does not require very powerful naval means, and its traction eons10 makes it possible to envisage interchanging in service the part of the frame supporting the work floor to replace it with a similar frame comprising different accessories made necessary by a new phase of work.

In the extreme, it can be completely moved leaving only the base at the bottom.

Figure 1 of the board I represents the entire structure ia in the working position.

It consists of a heavy base (1) in the form of a frame leaving free the central working location (2).

At the four corners of this base rest known columns such as (î) provided with integrated floats (4) and cardan joints (5) also known.

On the tops (6) of these columns rests, by means of new articulations (7), the rigid frame (ô) carrying the work floor (9) · This arrangement forces the work floor to remain parallel to the bottom sailor whatever the oscillations of the platform. The frame (δ) comprises in particular floats (1O) (11) and (12) which, with the floats (4), contribute to giving positive buoyancy to the column-frame assembly and which also allow the frame ( δ), separate from the structure, to float by its own means (fig. 2 plate i) and to be movable by towing.

In (13) is shown a set of subsea well heads which can for example constitute one of the works that can be carried out using this platform.

The piping (14) draining the production of the wells (13) is brought to the surface on the floor (9) by rigid tube elements (15) (16) connected by hoses (t?) (18) to the passage of the joints. .

19474

Plate H indicates the main phases of implementation of the equipment. Each of these phases involves known methods, essentially ballasting or deballasting of capacities, or guidance systems by guide lines and traction on these lines.

These methods are not part of the invention. Only part of it is the sequence of ease in place of the constituent elements which leads to the construction of this new platform.

In fig. 3 seule the base (1) alone is towed to the site and poured vertically from the future work point.

- · In fig. 4 the columns (?) Towed successively are joined to the base.

In fig. 5 the semi-submerged frame (δ) is lowered and connected to the sonnet of the columns. None of these operations requires the intervention of a pontoon-crane.

The platform proposed by the invention is therefore capable of providing a stable working floor, for work in fairly deep waters, while being easy to dismantle and dismantle.

Bile is likely to find use whenever it is necessary to carry out long-term work at sea or even when it is necessary to carry out permanent support. As such, it could have preferential applications in drilling operations and production of oil wells in aer.

19474 η. .