JPS6221926B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for positioning a platform of the offshore type (i.e. installed on the ocean or other liquid environment), particularly for an oil production installation.

In the past, the platform was often installed on the seabed or other ground before digging a shaft; other,
The task is further complicated by the time required to build the platform and the need for an engine to dig the trench.

If said platform can be mounted on the pipe head of a shaft, i.e. a shaft previously excavated by means of equipment suitable for said pattern excavation and reusable in different excavation positions, This reduces the overall installation time and simplifies the platform structure.

However, in such a case, the head of each shaft installed on the bridge of the platform must be aligned vertically with the head of each shaft previously excavated in the seabed when it is assembled. Special methods and equipment must be resorted to.

The main object of the invention is therefore to make such a method and device particularly simple to implement and construct.

According to the invention, at least one bottom plate comprises:
In order to correctly position the platform with respect to a template which is fixed to the seabed and supports the heads of the pipe or tubes corresponding to the shaft excavated in the seabed, the platform is previously placed in close proximity. and then controllable from said platform by means of cables extending to various points anchored on said seabed, and by said various points and control devices. A translational movement of the platform and a rotational movement about the vertical axis of the platform act again on the platform, allowing it to be moved to a position oriented by suitable optical, ultrasonic or other types of equipment. ing.

Particularly in weight-bottomed platforms which have come to be positioned on the seabed in order to ensure a constant anchorage, at least one chamber is provided in the bottom plate and a suitable play is provided in accordance with the outer shape of the shaft plate. A chamber of matching shape is formed by the gap.

In a further arrangement of the invention, a guiding device is provided so that the bottom plate can be guided precisely relative to the shaft plate when the platform is lowered into its berthing position.

This guide device consists of guide columns arranged around the shaft plate and a similarly slidable guide tube carried by the bottom plate of the platform so that when the platform is lowered, the head of the pile and a guide tube adapted to engage with the guide tube.

The guide tube is carried by a weight base plate, in particular vertically above the guide pile.

The play is initially activated at the moment when the guide tube engages the head of the pile, and then this play is reduced by a shoulder provided inside the tube.

In addition to the device described above, the invention includes other devices that can be used to solve the problems mentioned above.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

According to the present invention, various parts are attached to a template P (Figs. 1 to 3) which is fixed to the ground in advance.
(FIG.), which plate is adapted to have one or more pre-drilled shafts opening therein in a known manner. On this plate, which is called the "multi-shaft plate", a marine platform in the form of a sinker bottom plate 1 is anchored, and on this bottom plate there are pillars 3 and 3.
Alternatively, the upper bridge 2 is supported by other devices. The height of the pillar is a function of the depth of the seabed F, and in order to vertically align the shaft of the plate P and the shaft head of the bridge 2 when positioning the piping, the height after anchoring must be adjusted as described below. It is necessary to ensure that the

The initial position when transported to the workpiece, that is, the lower surface 4 of the bottom plate 1 is a certain distance h above the plate P (Fig. 1)
The platform now located at is made to occupy the first proximate position (Figure 2);
From this planar position it is approached vertically to its final position.

When the platform is of the weighted bottom plate type as shown in the figure, a small chamber 5 is provided on the side of the lower surface 4, and the wall of this chamber is provided with a suitable lateral clearance to accommodate the multi-hole plate P and its attached members. It is placed over the top.

Said chamber 5 opens into the underside 4 of the bottom plate 1, in which case a recess formed in the bottom plate is adapted for passing a pipe which will later connect the well head of the bridge and the well head of the plate P.
Note that this chamber can be formed over the entire height of the bottom plate 1.

Said chamber 5 can often be formed transversely (viewed in plan) to the vertical central axis ZZ (FIG. 1) of the platform, for example when the wellhead of the bridge 2 itself is offset from this axis. can.

Therefore, in order to facilitate horizontal translation and rotation about the vertical axis from this close position, according to the invention suitable devices are provided in communication with the platform and suitable optical, ultrasonic or other methods are used to facilitate the movement. It is necessary to align the axis of the shaft of the bridge 2 with the axis of the shaft of the plate P in combination with a suitable positioning device. Such an arrangement allows the platform to move horizontally and rotate about a vertical axis under the pulling force of a winch (or other device). This objective is achieved by arranging the tension cables in at least one pair of parallel lines offset from the axis so as to generate opposing rotational moments.

The above-mentioned position adjustment work is carried out in combination with optical, ultrasonic or other types of locating devices disposed on the platform and the plate P, as is well known.

1 to 3 diagrammatically illustrate a method that can be used to carry out the process described above.

To carry out the first positioning operation, for example, several tugboats R ₁ (Figs. 2 and 3) are used, with mooring cables 6 attached at various points around the platform.
Add force. The tug can, for example, serve as a safety device to prevent the mooring cable from breaking during subsequent adjustment operations and can be maintained in a fixed position.

When carrying out the second position adjustment work, the cable 7 for this purpose (Figs. 1 to 3) is first placed on the seabed, and one end 8 of it is driven into the seabed F (Figs. 2 and 3). fixed to a pile 9, anchor or similar, and the other end is attached to a buoy 10 (first
(Figure).

When this arrangement is carried out, the other end is captured by a cable or rope 11 wound around a winch 12 carried by the bridge 2 of the platform, and a connection is established between each pile 9 and the winch 12. I have to.

FIG. 2 shows a plan view of the arrangement adopted for the cable 7.

A total of four cables are used along parallel lines offset by a distance e as shown, and the method can be adjusted as described above by applying tension by four winches 12 as required. can.

Each cable 7 is connected from the buoy 10 by a rope 11
The work of removing the water is carried out in a well-known manner by the tugboat R ₂ (Fig. 1).

First, the end of the cable 7 is cut off from the buoy and then tied to the rope 11 (dotted line in FIG. 1).

In the advantageous arrangement shown in FIGS. 1 and 3, it is ensured that the tensile forces acting on the platform are as low as possible, ie on the base plate 1. For this purpose, the cable 11 or 7 is passed through an intermediate pulley 13 near the bottom plate (FIGS. 1 and 3). Other pulleys 14, 15
is for guiding the cable to the winch 12.

In this way, the cables 11, 7 can be made as short as possible, and their extension always minimizes the fluctuations in the tensile force, especially those due to the influence of the wind, so that a decrease in the adjustment accuracy can be avoided.

It should be noted that the reaction force on the platform approaches the horizontal, thereby preventing the generation of disturbing tilting moments.

Furthermore, the resultant force of these reactions passes near the center of rolling and the positioning portion of the bottom plate.
The effects of anchoring and positioning reactions on platform roll are therefore reduced.

Finally, as shown in FIGS. 1 and 3, the operating rope or cable 11 and the crane 16
and connect the operation cable to the end of the crane in front of the connection part with the cable 7.

In Figure 3, two cables 7 and 11 are connected to one
It can be seen that the tensile force of the winch 12 is applied across these two cables. Of course, it is also possible to preliminarily store a certain length of cable on the buoy 10 and pay it out and connect it directly to the winch 12 without using the continuous method.

In order to precisely position said assembly on the plate P, suitable devices are also provided for vertically guiding the platform and bringing it over said plate during the next operation of anchoring on the seabed F. It is being

Such a device can be formed in various ways.

It is preferable to use the method shown in FIGS. 4 to 6. When using this method: - First, the plate P is combined with the protrusion device that makes insertion possible. This device is preferably formed, for example, by pegs 18 inserted around the circumference of said plate and precisely positioned relative to said plate.

- then by means of said weight base plate 1 a guide tube 19 or other suitable device is supported, preferably inside the chamber and opposite its wall, which engages with the free end of said column 18; Make it.

The guide tube 19 is mounted so as to slide relative to the chamber 5 (20 in FIGS. 4 to 6), and the guide is first placed over the column (20 in FIGS. 4 to 6).
and FIG. 5), so that the platform can be pushed down unimpeded by the guide sliding against the base plate 1.

The upper end of the pillar 18 is pointed as indicated by 21. The guide tube 19 is operated by a rope 22 from the bridge 2.

FIG. 7 is a perspective view of the assembly of plate P and base plate 1, showing details of said chamber 5 and guide tube 19. Optical equipment (such as a television camera) is represented by 23, and hydraulic-acoustic equipment is represented by 24, 2.
5.

This figure also shows a centering member or collar 27 which must be fitted inside the guide tube 19, but this is for accurate centering with respect to the column and is not suitable for this purpose. A device can be provided.

The vertical guidance of the platform can of course be carried out in a manner different from that shown. For example, in the variant shown in FIG. 6, instead of using said guide tube, there is provided a fixed guide catch 26 which is simply a projection carried by the chamber 5 and which is carried by the face of the column 18 or by the plate P. It can be made to slide against a completely different supported member.

Said pile 18 can be arranged at a distance from the plane of the plate P, in which case the guide tube 19 instead of being mounted slidingly against the wall of the chamber 5 can be mounted on a suitable plate formed in the bottom plate 1. It is made to pass through the inside of a groove.

In yet another embodiment, the platform can be installed on a sinker bottom plate, for example, on a multi-well plate P placed on the seabed, and the sequence of operations in this case is as follows.

- Positioning is done in advance by a tugboat, and the pre-installed mooring cable 7 is connected to the pulling cable 17.
Connect to. When this work is carried out, the platform is ballasted to a suitable level so that there is a safe distance h (for example 1 to 2 meters) between the high point of the board or pile and the low point of the bottom plate.

- Position the platform by applying mooring cable force with the winch 12 so that the guide tube 19 is directly above the pillar, and at this time confirm the position with the television camera 23. Next, the tube 19
is lowered until at least its lower part covers the stake 18 and the centering shoulder 27 abuts the top of the stake, and the general positioning is performed as shown in FIG.

- Insert the ballast into the platform until the low point of the bottom plate (Figure 5) is slightly off the ground (eg 20-50 cm).

- Correct the position by applying force to the mooring cable with a winch so that the centering shoulder 27 passes over the pile 18 and the guide tube 19 descends under its own weight and reaches the ground; (position shown in Figure 5).

- until the platform makes contact with the ground (6th
Figure) Perform final balancing.

All these operations should be carried out when swell, wind and current conditions affecting mooring cables, piles and guide pipes are favorable.

The present invention can be modified in various ways within the scope of the claims.

[Brief explanation of the drawing]

Figures 1 and 2 are elevational and plan views, respectively, of a platform previously anchored to the ground and installed on a board with one or more shafts for positioning and anchoring the equipment. Show stages. FIG. 3 shows the assembly shown in FIG. 1 in its final working stage. Figures 4 to 6 are enlarged details of said assembly, representing three successive stages of operation in lowering the platform to its final berthing position, with Figure 6 showing a further variant of the invention. . FIG. 7 is an enlarged exploded perspective view of the main components of the present invention, partially broken away. In the figure, 1 is the weight bottom plate, 2 is the upper bridge, 3
is the pillar, 4 is the bottom surface, 5 is the chamber, 6 is the mooring cable, 7
is a cable, 9 is a stake, 10 is a buoy, 11 is a rope, 12 is a winch, 13 is an intermediate pulley, 1
4 and 15 are pulleys, 16 is a crane, 18 is a stake,
19 is a guide tube, 22 is a rope, 23 is an optical device,
24 and 25 are hydraulic-acoustic devices, 26 is a guide stopper, and 27 is a collar.

Claims (1)

[Scope of Claims] 1. A weighted bottom plate 1 which is fixed in advance to the seabed F in the sea and positioned above a template P supporting a pipe head of a vertical pile. In a device for positioning a platform of an oil production facility having at least one overlapping chamber 5, a platform previously placed in a floating state at an approximate position above the template P is placed in a different position fixed to the seabed. It is connected to the anchorage point 8 by cables 7 controlled by a winch 12 located on the platform, and by the operation of these cables 7 it is connected to an optical 23 ultrasonic or other type 24, 25 position measuring device. and the vertical axis of the platform Z-Z
1. A positioning device for a platform of an oil production facility, characterized in that it is configured to be able to transmit surrounding rotational motion and translational motion to the platform. 2. In the device according to claim 1, the guiding devices 18, 19 which ensure the vertical guidance of the bottom plate 1 of the platform during its downward movement to the anchoring position on the seabed are provided with templates. A positioning device for a platform of oil production equipment, characterized in that it is connected to a platform P. 3. The device according to claim 1, in which the cable 7, the respective anchorage point 8 to the seabed and their winches on the platform are such that said cable 7 supports a vertical axis, in particular a pipe head of a vertical pile. A positioning device for a platform of an oil production facility, characterized in that the platform is arranged in two or more pairs of parallel cables offset with respect to the center axis Z--Z of a plate. 4. In the device according to claim 3, the cables 7, 11 pass through the guide pulley 13 located at a sufficiently low position at the point where the cables 7, 11 reach the platform, so that the operating part of the cable that serves to position the platform is horizontal. 1. A positioning device for a platform of oil production equipment, characterized in that the device is configured to be oriented in a direction not far away from the platform. 5. In the device according to any one of claims 1 and 2, the guide device has a stake 18 inserted around the template P by drilling or other device, In contrast, the piles are slidable on members 19 supported by the bottom plate 1 of the platform, and these sliding members are adapted to engage the piles 18 and are slidably mounted on tubes 19.
A platform positioning device for oil production equipment, characterized by comprising: 6. The device according to claim 5, wherein the tube 19 has a wider cross section than the cross section of the pile 18.
A device for positioning a platform of an oil production installation, characterized in that the platform includes an inner shoulder 27 which is adapted to ensure a more precise positioning at the end of assembly. 7. In the device according to claim 5, the pile 18 is disposed close around a template P carrying the tube head of the vertical pile, and is slidable into a chamber overlapping the template. 1. A positioning device for a platform of an oil production facility, characterized in that a movable tubular guide member 19 is attached. 8. The oil production apparatus according to claim 5, characterized in that the inner wall of the chamber 5 of the bottom plate 1 is provided with a protrusion 26 that slides against the outer surface of the guide pile 18. Equipment platform positioning device.