CN102418480A - Riser support device under ultra-deep sea water - Google Patents

Abstract

The invention discloses an ultra-deep sea underwater riser support device, which comprises a standpipe support buoy, a tension mooring device and an umbilical cable; the upper part of the standpipe support buoy is provided with a wellhead head A, and the lower part of the wellhead head A is a buoy that penetrates the riser support The channel; the riser support buoy is a starfish structure, that is, the edge of the central column structure buoy is connected to three rectangular section cantilever buoys, and their included angle on the plane is 120°. The end of the cantilever buoy of the present invention adopts a neutral buoyancy truss structure, which can meet the buoyancy requirements of the standpipe support buoy by reducing the proportional length of the truss structure on the cantilever buoy or increasing the length of the cantilever buoy, which can greatly simplify the construction of the cantilever buoy. The construction process is difficult and the construction cost is reduced. The invention provides tension force for the TTR riser through the standpipe support buoy, reduces the dynamic load supported by the water surface floating production device, reduces the requirements for the water surface floating production device, thereby reducing the construction cost of the water surface floating production device .

Description

An ultra-deep sea underwater riser support device

technical field

The invention relates to a deep sea oil and gas field development technology, in particular to an underwater riser support device used for the development of an ultra deep sea oil and gas field.

Background technique

As the only structure connecting the water surface part and the underwater production system, the riser is an important part of the development of offshore oil and gas fields, especially playing a key role in the development of deep sea and ultra-deep sea oil and gas fields. At present, the widely used and mature production riser in the field of deep sea petroleum engineering is the TTR riser, that is, the top tension riser.

However, in the ultra-deep sea environment, the weight of the riser in the water will naturally increase sharply with the increase of water depth and water pressure; at the same time, the increase in the weight of the riser will also require a great increase in the tension at the top of the riser, which has great impact on the TTR standpipe. The applicability and economy of the tube pose very serious problems. In addition, since the standpipe is connected to the surface floating production unit, as the water depth increases, the huge underwater riser load will increase the dynamic load that the water surface floating production unit must bear, thereby increasing the capacity of the water surface floating production unit. construction and operating costs. Therefore, if the traditional TTR riser production system is adopted, the overall production cost of the oil field is huge.

Contents of the invention

In order to solve the above-mentioned problems in the prior art, the present invention will design a support device for an ultra-deep sea underwater riser, which can greatly improve the Traditional TTR risers and surface floating production devices have the ability to work in ultra-deep sea environments, while greatly reducing production costs.

In order to achieve the above object, the technical scheme of the present invention is as follows:

An ultra-deep sea underwater riser support device, comprising a riser support buoy, a tension mooring device and an umbilical cable;

The upper part of the standpipe support buoy is provided with a wellhead head A, and the lower part of the wellhead A is a passage through the standpipe support buoy; the riser support buoy is provided with an intake valve above it and an exhaust valve below it , the inlet valve is connected with the floating production device located on the water surface through the umbilical cable; the floating production device on the water surface sends the gas to the riser support buoy through the umbilical cable, and controls the ingress and egress of the gas through the inlet valve and the exhaust valve , so as to adjust the buoyancy of the riser supporting the buoy;

The riser support buoy is a starfish structure, that is, the edge of the central column structure buoy is connected with three rectangular section cantilever buoys, and their included angle on the plane is 120°; the end of the cantilever buoy adopts a neutral buoyancy truss structure, The three cantilever buoys with rectangular section are mechanically connected to the edge of the central column structure buoy.

The tension mooring device includes a tension cable and a pile foundation, and the riser support buoy is moored on the pile foundation of the seabed through the tension cable to constrain the movement of the riser support buoy in the water, and provide a certain degree of tension for the riser support buoy. Stability support.

In the present invention, the riser supporting buoy is replaced by a central column structure buoy; the tension mooring device is replaced by a TTR riser tensioned by the central column structure buoy.

The standpipe support buoy of the present invention is provided with a pipeline transfer device. There are three wellheads A on the upper part of the standpipe support buoy. The pipelines at the wellhead A are connected to the pipeline transfer device after being collected.

Risers supported by the present invention include TTR risers and flexible risers. The upper end of the TTR riser is connected to the wellhead head A on the upper part of the riser supporting buoy, and the lower end is connected to the wellhead device arranged on the seabed; the lower end of the flexible riser is connected to the upper part of the riser supporting buoy, and the upper end is connected to the floating production of the water surface device. Thus, the riser support buoys provide the required tension for the TTR riser and the support platform for the flexible riser.

Compared with the prior art, the present invention has the following beneficial effects:

1. The riser support buoy of the present invention has a flexible structure, which can be a central column structure buoy or a starfish structure buoy; the cantilever buoy is mechanically connected to the edge of the central column structure buoy, which simplifies the installation and disassembly process of the cantilever buoy.

2. The end of the cantilever buoy of the present invention adopts a neutral buoyancy truss structure. When the design requires an additional increase in the buoyancy of the standpipe support buoy, it is only necessary to reduce the proportional length of the truss structure on the cantilever buoy or increase the length of the cantilever buoy; if the design buoyancy requirements are met, the truss structure can be increased on the cantilever buoy Proportional length, thereby reducing the weight of the riser supporting the buoy. In summary, the difficulty of the construction process of the cantilever buoy can be greatly simplified and the construction cost can be reduced.

3. The present invention provides tension force for the TTR riser through the standpipe support buoy, which reduces the dynamic load supported by the surface floating production device, reduces the requirements for the water surface floating production device, and thus reduces the cost of the water surface floating production device. construction cost.

4. The present invention provides tension force for the TTR riser through the standpipe support buoy, which greatly improves the working water depth of the traditional TTR riser.

Description of drawings

The present invention has 3 accompanying drawings, wherein:

Fig. 1 is the overall schematic diagram of the ultra-deep sea underwater riser support device of the present invention;

Fig. 2 is a top view of the riser support buoy of the present invention;

Fig. 3 is an overall schematic diagram of the engineering application of the present invention.

In the figure: 2. Truss structure, 3. Wellhead head A, 4. Intake valve, 5. Exhaust valve, 7. Tension cable, 8. Pile foundation, 9. Umbilical cable, 10. Standpipe support buoy, 11, Central column structure buoy, 12. Cantilever buoy, 15. Floating production device, 16. Water surface, 17. Seabed, 20. Flexible riser, 21. Remote control robot, 22. Pipeline transfer device, 25. TTR riser, 26. Well head B.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 1 , an ultra-deep sea underwater riser support device includes a riser support buoy 10 , a tension mooring device and an umbilical cable 9 .

As shown in Figure 1-2, the riser support buoy 10 is a starfish structure, that is, the central column structure buoy 11 is connected to three cantilever buoys 12 with rectangular cross section at the edge, and their included angle on the plane is 120°, forming a radial shape. . The end of the cantilever buoy 12 adopts a neutrally buoyant truss structure 2 . When the design requires an additional increase in the buoyancy of the riser support buoy 10, it is only necessary to reduce the proportional length of the truss structure 2 on the cantilever buoy 12 or increase the length of the cantilever buoy 12; if the design buoyancy requirements are met, the truss can be increased The proportional length of the structure 2 over the cantilever buoy 12 reduces the overall weight of the riser support buoy 10 . To sum up, the difficulty of the construction process of the riser supporting buoy 10 can be greatly simplified and the production cost can be reduced.

As shown in Figure 1, the described tension mooring device comprises tension cables 7 and pile foundations 8; the described riser supports the buoy 10 by three tension cables 7 (in the accompanying drawings, the overall structure is clear for illustration, only two are shown. Tension cables) are moored on the pile foundation 8 located on the seabed 17 to constrain the movement of the riser support buoy 10 in the water and provide certain stability support for the riser support buoy 10 . At the same time, the tension cable 7 can bear the overtension force that the riser supports the buoy 10 may bring, and prevent the TTR riser 25 from breaking due to the overtension force that may be borne.

As shown in Figure 1, the riser support buoy 10 has a buoyancy adjustment device. When it is necessary to increase the net buoyancy of the riser support buoy 10, the floating production device 15 on the water surface 16 is connected to the riser support by an umbilical cable 9. The intake valve 4 on the top of the buoy 10 inputs nitrogen gas (anti-corrosion) into the riser support buoy 10; when the net buoyancy requirement is reduced, the floating production device 15 remotely opens the exhaust valve 5.

As shown in Figure 1, the riser support buoy 10 is located at H1 (about 200-350m) below the water surface 16, so as to avoid the turbulence zone under the sea surface, so that the riser support buoy 10 is hardly affected by the near sea surface. Maintain good in-position performance under the influence of strong wind, sea waves and current loads.

As shown in Figures 2-3, in order to simplify the installation process, the riser support buoy 10 is provided with a pipeline transfer device 22 . There are three wellheads A3 on the upper part of the standpipe support buoy 10, and the pipelines at the wellheads A3 are collected and connected to the pipeline transfer device 22.

Figure 3 is an overall schematic diagram of the engineering application of the present invention. The upper end of the TTR riser 25 is connected to the wellhead head A3 on the upper part of the riser supporting buoy 10, and the lower end is connected to the wellhead head B26 arranged on the seabed; The floating production unit 15 is connected. Thus, the riser support buoy 10 provides the required tension for the TTR riser 25 and provides a support platform for the flexible riser 20 . The remote control robot 21 is on standby near the H1 under the water surface 16, and is responsible for the monitoring work in the water and the connection and release work of related components.

The oil reservoir on the seabed finally reaches the floating production unit 15 on the water surface 16 through the wellhead head B26 on the seabed 17, the TTR riser 25, the riser support buoy 10, and the flexible riser 20, so as to carry out offshore oil and gas field engineering develop.

Since the present invention utilizes the net buoyancy of the standpipe support buoy 10 to provide the required tension force for the TTR riser 25, compared with the conventional technology, the present invention can greatly reduce the working load of the water surface floating production device 15, thereby reducing the pressure on the water surface. The design requirements and construction requirements of the floating production device 15 further greatly reduce the technical difficulty and construction cost of constructing the surface floating production device 15 .

In addition, preferably, according to actual engineering needs, the starfish structure of the riser support buoy 10 of the present invention can be simplified into a central column structure buoy 11 by mechanically removing the three cantilever buoys 12 . At the same time, the tension mooring is removed, and the TTR riser 25 tensioned by the central column structure buoy 11 provides a stable support for the central column structure buoy 11 .

Claims (3)

1. a ultra deep-sea submerged riser bracing or strutting arrangement is characterized in that: comprise that standpipe supports floating drum (10), tension force mooring gear and umbilical cables (9);

Described standpipe supports floating drum (10) top and is provided with well head head A (3), and well head head A (3) bottom is for running through the passage that standpipe supports floating drum (10); Described standpipe supports floating drum (10), is provided with air intake valve (4) above it, the below is provided with drain tap (5), and described air intake valve (4) is connected with the Floating Production device (15) that is positioned at the water surface (16) through umbilical cables (9); The water surface (16) Floating Production device (15) is delivered to standpipe through umbilical cables (9) with gas and is supported floating drum (10), and passes through the turnover of air intake valve (4) and drain tap (5) control gas, regulates the buoyancy that standpipe supports floating drum (10) with this;

It is starfish formula structure that described standpipe supports floating drum (10), and promptly central rods structure floating drum (11) edge connects three square-section cantilever floating drums (12), and their angles in the plane are 120 °; The terminal trussed construction (2) that adopts neutral buoyancy of described cantilever floating drum (12), described three square-section cantilever floating drums (12) are connected central rods structure floating drum (11) edge through mechanical system;

Described tension force mooring gear comprises tension cables (7) and pile foundation (8); Standpipe supports floating drum (10) and goes up with the motion of constraint standpipe support floating drum (10) in water through the pile foundation (8) of tension cables (7) mooring in sea bed (17), and provides certain stability to support for standpipe supports floating drum (10).

2. a kind of ultra deep-sea according to claim 1 submerged riser bracing or strutting arrangement is characterized in that: described standpipe supports floating drum (10) and replaces with central rods structure floating drum (11); Described tension force mooring gear is replaced by the TTR standpipe (25) of central rods structure floating drum (11) tensioning.

3. a kind of ultra deep-sea according to claim 1 submerged riser bracing or strutting arrangement; It is characterized in that: described standpipe supports floating drum (10) and is provided with pipeline transferring device (22); Standpipe supports floating drum (10) top has three well head head A (3), and the pipeline that well head head A (3) locates compiles the back and is connected with pipeline transferring device (22).

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