KR20170003323U

KR20170003323U - Subsea slug catcher tank and slug catcher system

Info

Publication number: KR20170003323U
Application number: KR2020160001422U
Authority: KR
Inventors: 임기호
Original assignee: 대우조선해양 주식회사
Priority date: 2016-03-16
Filing date: 2016-03-16
Publication date: 2017-09-26

Abstract

The slag catcher system of the present invention includes a steel pipe riser vertically installed from the seabed for transporting a polyphase fluid from a seabed well, a water pipe connected to the steel pipe riser in water for temporarily collecting a fluid rising through the steel pipe riser, The slag catcher system of the present invention includes a catcher tank and a flexible riser connected to the offshore slag catcher tank by an offshore offshore plant to move the fluid in the underwater slag catcher tank, To overcome the limitations of installing on offshore plants.

Description

Technical Field [0001] The present invention relates to an underwater slug catcher tank and a slug catcher system including the slug catcher tank.

The present invention relates to a slug catcher tank for eliminating or reducing slug due to the fluid phase separation phenomenon inside a riser installed for transferring crude oil and gas mixed fluid from a subsea well to an offshore plant, .

Necessity for the mining and production of resources (crude oil and gas) The plant is equipped with various equipment and systems for the transportation, treatment and production of seabed resources.

The offshore plant in the present invention is used as a concept that includes both fixed and floating platforms for production and processing.

A riser is a steel pipe or a flexible pipe used to move fluids (crude oil, gas, or a mixture thereof) between a seabed well and an offshore plant.

Depending on the environmental condition to be installed and the type of offshore plant, a simple caterpillar shape, a lazy wave shape and the like can be applied. In terms of cost, the simple suspension shape is the most economical and easy to install compared to other shapes. However, the simple suspen- sion shape receives a load due to the movement of the float directly in the area where the riser and the bottom face meet (ie, the touchdown zone), which may lead to collapse or fracture problems on the strength side and fatigue side.

As an alternative to this, it is possible to solve the problem in terms of strength and fatigue by absorbing the load due to the motion of the float using a flexible pipe, but it has a drawback that the cost is relatively increased.

As shown in FIG. 1, a system in which a riser configuration is constructed by using the above two types of pipes in combination is a hybrid riser system, in which a buoyancy tank 3 is connected to a steel pipe riser 1 (C) to a height close to the water surface, and the fluid is transferred from the end thereof to the offshore plant (F) through the flexible riser (2).

However, in such a system, when a fluid flows from a low place to a high place like a riser, a slug phenomenon occurs.

The fluid transported from the reservoir through the bottom pipe is a polyphase fluid containing crude oil, water, and gas. The difference in density between materials (especially liquids and gases) in the fluid during the lifting of this fluid through the riser to the offshore offshore plant causes a velocity difference between the liquid and the gas.

When a relatively low-velocity liquid is stacked inside a riser of a certain section to interfere with the flow, the pressure gradually increases. When the pressure reaches a certain pressure, the fluid that has been deposited is transferred at one time. This is one of the various slug phenomena. Such a slug can impact a device that needs to separate the fluid with a large amount of liquid being transported at a high speed at a time, thereby damaging some or all of the devices, resulting in platform downtime.

Slug catcher (4, Slug Catcher) is equipment to prepare against such slugs. In the case of offshore plant, Vessel Type with large volume which can absorb a large amount of liquid is mainly installed. However, there is a disadvantage in that the size of the platform is increased because the space above the offshore plant and the capacity of the float itself must be secured by the volume corresponding to the capacity of the slug catcher.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide an underwater slug catcher tank and a slug catcher system capable of overcoming the limitations of installing the slug catcher on an offshore plant, And the like.

The slag catcher system according to one aspect of the present invention includes a steel pipe riser vertically installed to transport a multiphase fluid from a seabed well, a fluid pipe connected to the steel pipe riser in water for temporarily collecting a fluid rising through the steel pipe riser An underwater slug catcher tank and a flexible riser connected to the offshore slag catcher tank by an offshore offshore plant to move the fluid in the underwater slug catcher tank.

And the steel pipe riser is laterally connected to the underwater slug catcher tank.

In addition, the underwater slug catcher tank may include a slug catcher tank portion for collecting fluid flowing through the steel pipe riser, and a buoyancy tank portion provided at an upper portion of the slug catcher tank portion.

Next, a slag catcher system according to another aspect of the present invention includes a steel pipe riser vertically installed from the sea floor to transport polyphase fluid from a seabed well, a water pipe connected to the steel pipe riser in water, And a plurality of flexible risers connected to the offshore slag catcher tank by an offshore offshore plant for moving the fluid in the underwater slug catcher tank.

The plurality of soft risers may include a first flexible riser connected from the top of the underwater slug catcher tank to the offshore plant for transferring gas in the fluid collected through the steel pipe riser, And a second flexible riser connected to the offshore plant for transferring the liquid in the fluid collected through the steel pipe riser.

The underwater slug catcher tank may include a slug catcher tank portion for collecting fluid flowing through the steel pipe riser, and a buoyancy tank portion provided in an upper portion of the slug catcher tank portion.

Meanwhile, the underwater slug catcher tank according to one aspect of the present invention is connected in water with a steel pipe riser vertically installed from the sea floor and a soft type riser connected to an offshore offshore plant to transport polyphase fluid from the seabed well, And the fluid ascending through the steel pipe riser is temporarily collected.

A slug catcher tank portion through which the fluid flowing through the steel pipe riser is collected,

And a buoyancy tank portion provided in an upper portion of the slug catcher tank portion.

The underwater slug catcher tank according to one aspect of the present invention is connected in water to a plurality of flexible risers connected to a marine offshore plant and a steel pipe riser vertically installed from the seabed to transport polyphase fluid from the seabed well , And temporarily collects the fluid ascending through the steel pipe riser.

Since the underwater slug catcher tank of the present invention is not installed on an offshore plant but installed in water, it is free from the limitations such as securing a space for installation on an offshore plant and securing a drainage amount.

Further, it is effective not to additionally provide a separate slug catcher tank but also to function as a slug catcher tank by retrofitting a conventional buoyancy tank.

1 schematically shows a relationship between a riser and a slug catcher for transporting a multiphase fluid from a conventional subsea well.
FIG. 2 illustrates a slug catcher system according to an embodiment of the present invention.
3 schematically illustrates an underwater slug catcher tank according to one embodiment of the present invention.
FIG. 4 shows an application example of an underwater slug catcher tank according to an embodiment of the present invention.
5 shows a slug catcher system according to another embodiment of the present invention.
6 schematically shows a submarine slug catcher tank according to another embodiment of the present invention.
FIG. 7 shows an application example of an underwater slug catcher tank according to another embodiment of the present invention.

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

The embodiments of the present invention described below can be modified into various other forms, and the scope of the present invention is not limited to the following embodiments.

FIG. 2 is a view showing a slug catcher system according to an embodiment of the present invention, FIG. 3 is a schematic view of an underwater slug catcher tank according to an embodiment of the present invention, FIG. 4 is a cross- FIG. 3 shows an example of application of an underwater slug catcher tank by the present invention.

The slug catcher system according to one embodiment of the present invention, which is referred to in FIGS. 2 to 4, includes a composite riser 10 to which a simple catenary riser 10 and a lazy wave riser 20 are applied together, The system includes a steel pipe riser 10, a soft riser 20, and a subsea slug catcher tank 100 to eliminate the slug phenomenon occurring in a hybrid riser system.

The steel pipe riser 10 is installed so as to extend vertically from the seabed line and to be connected to the side of the underwater slug catcher tank 100.

A riser support structure 11 for supporting the connection of the steel pipe riser 10 to the underwater slug catcher tank 100 is also provided.

The steel pipe riser 10 is provided with a steel material, providing a path through which the multiphase fluid can ascend from the seabed well.

The slug catcher tanks to be provided for eliminating the slag generated in the steel pipe riser 10 are connected to the steel pipe riser 10 and are provided in the subsea so that the fluid through the steel pipe riser 10 Stored in the slag catcher tank 100, and then transported to the offshore plant through a soft riser 20 connected to the underwater slag catcher tank 100. [

Conventionally, slug catcher tanks have to be provided on offshore plants, and in composite riser systems, steel pipe risers have been installed under buoyancy tanks with less vertical load.

In the present invention, the slug catcher tank is provided not in the offshore plant but in the water and is connected to the steel pipe riser 10, and the underwater slug catcher tank 100 is formed so as to function as a conventional buoyancy tank.

That is, the underwater slug catcher tank 100 includes a slug catcher tank unit 210 and a buoyancy tank unit 220 partitioned on the slug catcher tank unit 210.

The buoyancy tank unit 220 allows the underwater slag catcher tank 100 to float underwater by the buoyancy force, The tension of the steel pipe riser 10 is reduced.

The fluid collected in the slug catcher tank portion 210 is caused to move through the soft riser 20 leading from the slug catcher tank portion 210 to the offshore plant.

The fluid flowing through the steel pipe riser 10 is a fluid in which gas and liquid are mixed. In order to transfer the fluids, the flexible riser 20 is preferably connected at the bottom of the slug catcher tank 210, The fluid is delivered to the offshore plant through a soft riser 20 connected to the bottom.

Since the slag catcher system according to one embodiment of the present invention is configured as described above, it is not necessary to separately provide the slag catcher tank in the offshore plant, and the slug phenomenon is suppressed so that the fluid through the riser can be stably transferred to the offshore plant I will.

FIG. 4 illustrates an application example of the slug catcher system according to an embodiment of the present invention described above, wherein the underwater slug catcher tank in the previous embodiment is divided into a slug catcher tank unit and a buoyancy tank unit, 4 is characterized in that the underwater slug catcher tank portion 110 and the buoyancy tank portion 120 are physically constructed as separate tanks.

According to this application example, instead of retrofitting a conventional buoyancy tank, a conventional buoyancy tank is connected to a newly constructed underwater slug catcher tank, and a steel pipe riser and a soft riser are connected to an underwater slug catcher tank, Can be constructed.

FIG. 5 shows a slug catcher system according to another embodiment of the present invention, FIG. 6 schematically shows a submarine slug catcher tank according to another embodiment of the present invention, and FIG. 1 shows an application example of an underwater slug catcher tank according to an embodiment.

5 to 7, a slug catcher system according to another embodiment of the present invention includes a simple catenary riser (10) and a lazy wave riser (30, 40) from the sea floor to the offshore plant The system includes a steel pipe riser 10, a plurality of soft risers 30 and 40 and a subsea slug catcher 200. The system includes a plurality of soft risers 30 and 40, tank.

The description overlapping with the previous embodiment will be omitted.

In the previous embodiment, the soft riser is configured as one and the fluid temporarily collected in the underwater slug catcher tank is transferred to the offshore plant through one soft riser, while the soft riser in the present embodiment comprises the first soft riser 30, And the second flexible riser 40 form a flexible riser of two paths.

The fluid collected in the underwater slug catcher tank 200 can be divided into a liquid component and a gas component, the liquid component is located at the bottom of the tank, and the gas component is located at the top of the tank.

The first soft type riser 30 functions as a line from the upper part of the slag catcher tank 210 of the underwater slag catcher tank 200 to the offshore plant and serves as a line through which a gas component in the fluid is conveyed, Is connected from the lower part of the slug catcher tank part 210 to the offshore plant, and functions as a line through which the liquid component in the fluid is transferred.

To this end, the first flexible riser 30 may be configured to pass through the buoyancy tank portion 220, as shown.

In addition, as shown in FIG. 7, the underwater slug catcher tank 210 and the buoyancy tank 220 may be physically separate tanks, as in the application of the previous embodiment.

While the present invention has been described in connection with certain exemplary embodiments and drawings, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, Various modifications and variations are possible within the scope of equivalents.

100, 200: Underwater slug catcher tank
110, 210: slug catcher tank portion
120, 220: buoyancy tank portion
10: Steel pipe riser 11: Riser support structure
20: Flexible riser
30: first smoothing riser
40: second smoothing riser

Claims

A steel pipe riser vertically installed from the seabed to transport the multiphase fluid from the seabed well;
An underwater slug catcher tank connected to the steel pipe riser in water for temporarily collecting a fluid rising through the steel pipe riser; And
And a flexible riser connected from the underwater slug catcher tank to the offshore plant for moving the fluid in the underwater slug catcher tank.
Slug catcher system.

The method according to claim 1,
Characterized in that said steel pipe riser is laterally connected to said underwater slug catcher tank.
Slug catcher system.

The method of claim 2,
Wherein the underwater slug catcher tank comprises:
A slug catcher tank portion through which fluid flowing through the steel pipe riser is collected; And
And a buoyancy tank portion provided in an upper portion of the slug catcher tank portion,
Slug catcher system.

A steel pipe riser vertically installed from the seabed to transport the multiphase fluid from the seabed well;
An underwater slug catcher tank connected to the steel pipe riser in water for temporarily collecting a fluid rising through the steel pipe riser; And
And a plurality of flexible risers connected from the underwater slug catcher tank to an offshore plant for moving the fluid in the underwater slug catcher tank.
Slug catcher system.

The method of claim 4,
The plurality of softened risers may include:
A first flexible riser connected from the top of the underwater slug catcher tank to the offshore plant for transferring gas in the fluid collected through the steel pipe riser; And
And a second flexible riser connected from the bottom of the underwater slug catcher tank to the offshore plant for transporting liquid in the fluid collected through the steel pipe riser.
Slug catcher system.

The method of claim 5,
Characterized in that said steel pipe riser is laterally connected to said underwater slug catcher tank.
Slug catcher system.

The method of claim 6,
Wherein the underwater slug catcher tank comprises:
A slug catcher tank portion through which fluid flowing through the steel pipe riser is collected; And
And a buoyancy tank portion provided in an upper portion of the slug catcher tank portion,
Slug catcher system.

In order to transport multiphase fluids from the seabed wells, a pipe riser is installed vertically from the sea bed, and a flexible riser connected to an offshore offshore plant,
And temporarily collecting the fluid ascending through the steel pipe riser.
Underwater slug catcher tank.

The method of claim 8,
A slug catcher tank portion through which fluid flowing through the steel pipe riser is collected; And
And a buoyancy tank portion provided in an upper portion of the slug catcher tank portion,
Underwater slug catcher tank.

Connected to a plurality of flexible risers connected to a marine offshore plant and a steel pipe riser installed vertically from the seabed for the transfer of crude oil and gas from the seabed well,
And temporarily collecting the fluid ascending through the steel pipe riser.
Underwater slug catcher tank.

The method of claim 9,
A slug catcher tank portion through which fluid flowing through the steel pipe riser is collected; And
And a buoyancy tank portion provided in an upper portion of the slug catcher tank portion,
Underwater slug catcher tank.