WO1999060246A1

WO1999060246A1 - A method of connecting a delivery line to a submerged manifold, and a vertical connection module

Info

Publication number: WO1999060246A1
Application number: PCT/BR1998/000025
Authority: WO
Inventors: Sérgio Augusto FERREIRA DANTAS
Original assignee: Fmc Do Brasil Indústria E Comércio S.A.
Priority date: 1998-05-18
Filing date: 1998-05-18
Publication date: 1999-11-25
Also published as: AU7900298A

Abstract

The present invention refers to a method of connecting an import line to a manifold for extracting petroleum out of oil wells on the bottom of the sea, by utilizing a hydraulic tool, which basically consists of the following steps: a) connecting a first end of the import line (54) to a Christmas tree; b) connecting the second end of the import line (54) to a vertical connection module (MCV); c) launching the Christmas tree to the bottom of the sea, positioning it on the head of the oil well; d) launching the vertical connection module (MCV) to the bottom of the sea; e) connecting smoothly, in two stages, the vertical connection module (MCV) to a vertical hub (50) of a manifold (47), by means of a single manoeuver of the hydraulic tool (51); and f) connecting the electric pins of the vertical connection module to the respective sockets of the manifold, after completion of the connection of the vertical connection module (MCV) to the hub (50) of the manifold. The invention also refers to a vertical connection module for carrying out the method.

Description

A METHOD OF CONNECTING A DELIVERY LINE TO A SUBMERGED MANIFOLD , AND A VERTICAL CONNECTION MODULE

The present invention refers to a method of connecting an import line to a manifold for extracting petroleum out of the bottom of the sea, and to a vertical connection module for carrying out this method.

Prior Art

A known system for extracting petroleum out of the bottom o the sea is shown in a schematic drawing in figure 1. This system comprises a main structure or manifold 1 , which supports, for instance, eight assemblies, each of them being basically constituted by a base 2 and a tubular piece or horizontal hub 3. An equipment called Christmas tree 4 is placed onto the head of the drilled oil well 5, and an import line 6 joins the Christmas tree 5 to the horizontal hub 3, permitting the petroleum flow, as indicated by arrows 7. In this way, the petroleum is collected from the two wells in the manifold 1 and is led to the surface of the sea by means of a manifold or import line 8. At the surface the petroleum is then stored in a platform of tank-ship, shown in figure 2.

Figure 2 shows schematically the sequence of mounting the line 6 onto a horizontal hub 3, according to the following steps:

Step A - in this step, one can se the service ship 9, the tan-ship or platform 10, the line 6 arranged on the bottom of the sea, and line 8, through which the petroleum flows to the platform 10. One can also see the tip 1 of the line 6 and the manifold 1 , where the horizontal hub 3 is disposed. In this step, the service ship 9 is going down by means of winches, the hydraulic traction tool 12, as shown by the arrow 13.

Step B - The traction hydraulic tool 12, right after sitting on the manifold 1 , catches the end 11 of the flexible line 6, with the aid of robots called "rov" (not shown) and pulls said line 6 until its end reaches the horizontal hub 3. After this operation, the hydraulic tool 12 is then retrieved, as indicated by the arrow 14. Step C - After retrieving the tool 12, the service ship 9 lowers thye coupling hydraulic tool 12 by means of winches, as shown by the arrow 16. This tool 16 is designed to couple the end 11 of the line 6 to the horizontal hub 3.

Step D - In this step, the end 11 is fit into the horizontal hub 3 and the device 15 begins to be retrieved to the surface, as indicated by the arrow 17.

Step E - In this step, the import line 6 is already connected to the horizontal hub 3, and the petroleum flows to the surface through the export line 8, as indicated by the arrows 18, and is stored on the platform 10. The service ship 9 is then withdrawn to perform operations in other places.

Figure 3 shows in greater detail a side view of the horizontal hub 3, where one can see said hub 3 fixed to the manifold 1. One can also observe the line 8 for exporting petroleum to the surface, and the arrow 18 indicating the direction of the petroleum flow. In this figure, the import line 6 is not connected to the hub 3.

Figure 4 shows the top view of the hub 3, shown in figure 3.

It should also be pointed out that, although not shown in figures 3 and 4, line 6 has electric and hydraulic connections and the hub 3 has the respective electric and hydraulic sockets. In this way, when the coupling between the line 6 and the hub 3 is completed, electric and hydraulic circuits are formed for commanding the Christmas trees 5 from the platform 10.

Drawbacks of the Prior Art

One of the drawbacks of the prior art consists in that there is no need for two hydraulic tools and, consequently, two maneuvers for connecting the line 6 to the hub 3. As shown in figure 2, steps A and B consist of the traction maneuver, and steps C and D consist of the connection proper. The cost of these tools and of the maneuvers is extremely high, just as the maneuvers are complicated and time consuming.

Another drawback consists in that, during the connection of the import line 6 to the horizontal hub 3, damages often occur to the electric pins before they fit into the respective sockets, because it is very difficult to achieve a perfect alignment between the end of the line 6 and the hub 3. The same problem occurs with the hydraulic command tubes, the protruding tips of which are still more subject to damages than the electric pins. Object of the invention

The invention has the objective of providing the installation of a petroleum- importing line in a more simple and economic way, as well as to prevent damages to the electric pins and to the hydraulic connections.

This objective is achieved by a method of connecting an import line to a manifold, which utilizes a hydraulic tool, and comprises the following steps:

a) connecting a first end of the import line to a Christmas tree

b) connecting the second end of the import line to a vertical connection module;

c) launching the Christmas tree to the bottom of the sea, positioning it on the head of the oil well;

d) launching the vertical connection module to the bottom of the sea;

e) connecting, smoothly and vertically, in two stages, the vertical connection module to a vertical hub of a manifold, by means of a single maneuver of the hydraulic tool; and

f) connecting electric pins of the vertical connection module to the respective sockets in the manifold, after connecting the vertical connection module to the hub of the manifold.

In the present method, the hub of the manifold is placed vertically in order to enable the fitting of the vertical connection module.

In order to carry out this method, an equipment called vertical connection module is utilized, as already mentioned, which comprises a hoisting piece fixed to the upper region of the body of the vertical connection module (MCV); a mechanical connector for fixing the module to a vertical hub of a manifold; a funnel with a larger opening oriented downwards, therefore internally, a guide for guiding the connection of the vertical connec- tion module (MCV), said funnel being fixed to the lower region of the body of the vertical connection module; at least one tubular piece, turnable by 360°, coupled at an end to the body of the vertical connection module and, at the other end, couplable to a line coming from the oil well; a displaceable electric connection device for connection to a device that carries socket of the manifold; a shock-absorbing system for the second connection stage and a system for automatically fixing and releasing a sealing plate. The mechanical connector is basically constituted by rods fixed to a flange by means of nuts and by a locking ring that is actuatable by the rod.

The electric connection device is basically constituted by an orientation funnel and by a piston which carries electric pins internally.

The shock-absorbing system of the slow and smooth connection is constituted by a concentric annular piece, which actuates in an oil chamber during the second coupling stage.

The automatic fixing and releasing system of the sealing plate is constituted by pincers with several movable legs, said pincers penetrate an opening of the sealing plate and is actuatable by a locking hydraulic channel an by an unlocking hydraulic channel.

Advantages of the invention

Thus, one of the advantages of the invention consists in that, for connecting the import line to the hub of the manifold, only one hydraulic tool is utilized and a single maneuver is performed, that is to say, the import line traction maneuver, as in the prior art, has been suppressed and now, according to the invention, only the fitting of the vertical connection module to the vertical hub of the manifold is effected. Since these maneuvers are extremely expensive and time consuming, the process of the invention brings about a substantial reduction of the costs.

Another advantage of the invention is the fact that the connection between the module and the hub of the manifold is effected in two stages, that is to say, initially the module is approached to the hub until a narrow spacing results between them; then, in the second stage, the module is slowly and smoothly fit to the hub. In this way, the protruding tips of the hydraulic tubes of the module are slowly and smoothly connected to the respective openings in the hub, avoiding the frequent damages which occur at the time of the cou- pling according to the prior art.

Another advantage of the invention consists in that, after completing the mechanical connection between the vertical connection module and the hub, the electric connection system is actuated, which enables the slow and smooth connection of the electric pins of the vertical connection module to the respective sockets of the manifold. In this way, the damages which the electric pins frequently undergo during the connection according to the prior art are avoided.

Another advantage of the invention is the fact that the vertical connection module presents an automatic fixing an releasing system of a sealing plate which, after the con- nection is completed, sits on the surface of the vertical hub, thus guaranteeing the tightness of the line. In case a damage occurs to the sealing plate, this system enables one to replace it without the need for hoisting the module to the surface.

The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings:

- figure 1 is a know system for extracting petroleum out of the bottom of the sea, as already cited previously;

- figure 2 is a known mounting sequence of an import line to a horizontal hub, as already cited previously;

- figure 3 is a side view of a known horizontal hub;

- figure 4 is a top view of the hub of figure 3;

- figure 5 is a top view of a vertical connection module according to the invention;

figure 6 is a side view of the vertical connection module, as indicated in figure

5;

- figure 7 is another side view of the vertical connection module, of figure 5;

- figure 8 is a top view showing only the central part of the vertical connection view;

- figure 9 is a cross-section view, as indicated in figure 8, showing a sealing plate;

- figure 10 is another cross-section view, as indicated in figure 8, showing the sealing plate in greater detail; - figure 11 is a detail of an automatic fixing and releasing system of the sealing plate, as indicated in figure 10;

- figure 12 is a detail of the sealing plate, as shown in figure 9;

- figure 13 is a side view of a hydraulic tool installing the vertical connection module on a vertical hub of the manifold;

- figure 14 is a side view, after completion of the first stage of connecting the module to the hub;

- figure 15 is a view showing in detail a lacking ring, a concentric annular piece and an oil chamber;

- figure 16 is a side view, after completion of the second stage of connecting the module to the hub, also showing the piston which carries the electric contact pins already fit; and

- figure 17 is a view of the lines connected and ready for operation.

Figure 5 shows a top view of a preferred embodiment of the vertical connection module according to the invention, hereinafter called MCV. For a better understanding, figure 5 should be taken in conjunction with figure 6, which is one of the side view of the MCV, as shown in figure 5. In the two figures, a hoisting piece 19 can be seen, which is fixed to the body 20 of the MCV by means of screws 21. In the top portion of the MCV there is provided a flange 22, displaceable downwards by actuation of a hydraulic tool shown in figure 13. Rods 23 are fixed to the flange 22 by means of nuts 24 and are designed for driving the locking ring 25 downwards, which, as will be seen in figure14, engages the top edge of a vertical hub of a manifold, in order to fix the MCV to said hub. The assembly formed by the flange 22, rods 23 and locking ring 25 constitutes a device called a mechanical connector.

One can also see from the figures a funnel 26 with a larger opening oriented downwards and which serves for guiding the MCV during the descent as far as the bottom of the sea; an internal guide 27 with a semi-helical cylindrical profile, arranged inside the funnel 26, which is designed for guiding the MCV during the connection of the vertical hub. Two tubular pieces 28 and 29 are connected to the body of the MCV, so that they can turn by 360°. Flexible import tubes or lines are connected to the ends 30 of the tubular pieces 28 and 29, which bring the petroleum out of the well as far as the MCV. The turn capacity of the tubular pieces 28 and 29 permits total freedom of movement to the flexible lines and enables the connection of the MCV to the hub of the manifold. Starting from these tubular pieces 28 and 29, there are stretches curved tubes 31 , which are designed for leading the petroleum flow into the MCV.

Further, one can see from the figures a stretch of tube 32 with turn capacity, which is designed for connecting a tube called umbilical connection, to control hydraulically the Christmas tree arranged on the head of the oil well, as shown in figure 1. A sealing plate 33 is placed in the intermediate region of the MCV and is designed for making the sealing between the MCV and the hub of the manifold, as shown in greater detail in figure 15.

Figure 7 is another side view of the MCV showing the electric connection device

34, which is basically constituted by a guiding funnel 35 and by a downwardly displaceable piston 36 and which carries eiectric contact pins (not shown) internally. In this view, one can also see valves 37, actuatable by submarine robots or rovs, as shown in greater detail in figure 16, and an automatic fixing and releasing system 38 of the sealing plate 33, which is shown in greater detail in figures 8 and 12.

Figure 8 shows a top view of the central region of the MCV. This figure shows the cross-sections referring to figures 9 and 10, which show the sealing plate 33 and the automatic fixing and releasing system 38 of said plate. The system 38 is constituted by a pincers 39 with various legs 40, which penetrate in an opening of the sealing plate 33, the pincers 39 being fixed to the sealing plate when it is displaced downwards and its legs 40 open; and it releases the sealing plate when the latter is retrieved upwards and its legs close. The pincers is commanded by two hydraulic channels, a channel 41 impels the pincers downwards, thus bringing about the locking of the sealing plate, whereas the pincers 39 is retrieved through the channel 42, allowing said plate to be released.

Figure 11 , as shown in figure 10, shows the pincers 39 in greater detail, which has legs 40, a pincers retainer 43 and rings "O" 44 for sealing.

Figure 12, as indicated in figure 9, shows a partial detail of the sealing plate 33, where the sealing rings "O" 45 and 46 can be seen.

Figure 13 shows the MCV being installed on a vertical hub 50. A submerged structure of manifold 47 is laid on the bottom of the sea 48. On the manifold 47 there is a fixed base 49, which supports the vertical hub 50. A hydraulic tool 51 , supported by a steel rope 52, commands the descent of the MCV and is actuated by a hydraulic command 53. In the figure, one can also see one of the import lines 54, connected to the MCV, and the export line 55, connected to the vertical hub 50. The arrows 56 indicate the direction of petroleum flow, that is, by means of the import line 54 the petroleum is brought out of the well as far as the MCV, and by means of the export line the petroleum flows to the surface, being stored on the platform.

Figure 14 shows the MCV having completed the first connection stage, which constitutes, in fact, an approach, positioning the MCV on the hub, and leaving a narrow spacing between them, as shown in figure 15. In this condition of figure 14, one can also see that the electric connection 34 is still away from the devices that carries the sockets 61, disposed on the manifold 74.

Figure 15 shows the spacing 57 between the MCV and the hub 50, after completion of the first stage of connection. Then, the rod 23 will drive the locking ring 25, which will engage the upper portion of the shoulder 58 of the hub 50. A little below the shock- absorbing system of the connection is arranged, which allows the MCV to connect to the hub slowly and smoothly. This system is constituted by a concentric annular piece 59, which projects into the chamber 60, filled with oil.

Figure 16 shows the second connection stage, which is indeed the coupling proper of said MCV to the hub 50. In order for this stage to be carried out, a submarine robot or rov 62 actuates the valve through the panel of the rov of the manifold 37, thus clearing an opening (not shown) of the chamber 60, through which the oil flows, allowing the concentric annular piece 59 to slide downwards and to penetrate said chamber 60. In this way the piston 23 to goes down and pushes the locking ring 25 to the lower region of the shoulder 58 of the hub 50. Thus, after completion of the mechanical coupling between the MCV and the hub, the electric connection system 34 is hydraulically actuated, the piston 36 goes down, and the electric pins fit into the respective sockets (not shown) of the socket- carrying device 61 , thus completing the electric connection.

In this way, as already mentioned previously, the smooth connection between the MCV and the hub enables, consequently, a smooth engagement between the protrud- ing tips of the hydraulic command tubes in the MCV with the respective openings of the hub, thus avoiding the frequent damages which occur with the coupling of the prior art. ln this way, the electric pins connect to the sockets slowly and smoothly, thus avoiding the damages that occur in the prior art.

Finally, figure 17 shows the MCV free, without the hydraulic tool, which has been withdrawn, since the connection with the hub 50 has been totally completed. The ar- rows 56 indicate the petroleum flow with the line operating.

Besides the above presented embodiment, the same inventive concept can be applied to other alternatives or possibility of utilization of the invention. Therefore, it should be understood that the present invention should be interpreted in a broad way, its scope being determined by the terms of the accompanying claims.

Claims

1- A method of connecting an import line to a manifold for extracting petroleum out of the bottom of the sea, by utilizing a hydraulic tool, characterized by comprising the following steps:

a) connecting a first end of the import line (54) to a Christmas tree;

b) connecting the second end of the import line (54) to a vertical connection module (MCV);

d) launching the vertical connection module (MCV) to the bottom of the sea;

e) vertical connecting smoothly, in two stages, the vertical connection module (MCV) to a vertical hub (50) of a manifold (47), by means of a single maneuver of the hydraulic tool (51); and

f) connecting the electric pins of the vertical connection module to the respective sockets of the manifold, after completion of the connection of the vertical connection module (MCV) to the hub (50) o the manifold.

2- A method according to claim 1 , characterized in that the two-stage connection consists in that, in the first stage the vertical connection module (MCV) is approached to the vertical hub (50) of the manifold (47) until a narrow spacing (57) is achieved between them; and the second stage consists in the connection proper, in which the vertical connection module (MCV) is engaged slowly and smoothly with the vertical hub (50) of the manifold (47).

3- A method according to claim 1 or 2, characterized in that, in the second stage of connection, the protruding tips of the hydraulic command tubes, arranged in the vertical connection module (MCV), engage the respective openings of the hydraulic tubes of the hub (50) of the manifold. 4- A method according to claim 1 , characterized in that, after completion of the connection of the vertical connection module (MCV) to the vertical hub (50) of the manifold (47), an external piston (36) is driven, which carries electric contact pins at its end, these pins engaging the corresponding sockets in the manifold, by virtue of the actuation of the piston, thus closing the electric circuits of the line.

5- A vertical connection module for carrying out the method defined in claim 1 , characterized by comprising a hoisting piece (19), fixed to the upper region of the body (20) of the vertical connection module (MCV); a mechanical connector (22, 23, 24, 25) for fixing the module to a vertical hub of a manifold; a funnel (26) with a larger opening oriented downwards and fixed to the lower region of the body (20) of the vertical connection module; said funnel carrying a guide internally for guiding the connection of the vertical connection module (MCV); at least one tubular piece (28, 29), rotatable by 360°, coupled, at an end, to the body (20) of the vertical connection module and, at the other end, coupiable to a line coming from the oil well; an electric connection device (34), displaceable for connection to a device that carries the sockets of the manifold; a shock-absorbing system (59, 60) for the second connection stage and an automatic fixing and releasing system (38) of the sealing plate (33).

6- A vertical connection module according to claim 5, characterized in that the mechanical connector is basically constituted by rods (230 fixed to a flange (22) by means of nuts (24) and a locking ring (25) that is actuatable by the rods (23).

7- A vertical connection module according to claim 5, characterized in that the electric connection device (34) is basically constituted by a guiding funnel (35) and by a piston (36) that carries electric pins internally.

8- A vertical connection module according to claim 5, characterized in that the shock-absorbing system of slow and smooth connection is constituted by a concentric annular piece (59), which actuates in an oil chamber (60) during the second connection stage.

9- A vertical connection module according to claim 5, characterized in that the automatic fixing and releasing system (38) of the sealing piece (33) is constituted by a pincers (39) with several movable legs (40), said pincers penetrates an opening of the sealing plate (33) and is actuatable by a hydraulic locking channel (41) and by a hydraulic unlocking channel (42).