KR20160000269A - Gravity offshore structure and installation method thereof - Google Patents

Abstract

Disclosed are a gravity offshore structure and an installation method thereof. The gravity offshore structure according to an embodiment of the present invention comprises: a hull which includes a bottom surface part formed in a dual hull structure using a metal material and coming in contact with a seabed, multiple side wall parts vertically formed from the corners of the bottom surface part, and a deck part connecting the tops of the side wall parts to each other, and which receives particulate weights having higher specific gravity than water in the bottom surface part therein to be fixed to a fixed position in a shore; and one or more cargo tanks which are fixed to the inside of the hull, wherein the bottom surface part has multiple compartments which are arranged on the bottom in a horizontal lattice shape and receive the particulate weights injected from the outside through a transfer pipe. Therefore, the present invention prevents the structure from being deformed due to the pressure of the weights by dispersing the pressure applied to the seabed.

Description

TECHNICAL FIELD [0001] The present invention relates to a gravity type offshore structure,

The present invention relates to a gravity type offshore structure, and more particularly, to a gravity type offshore structure having a strong structure even in extreme marine environments such as wind, waves, tides, and earthquakes, and a method of installing the structure.

In general, the expansion of various industrial facilities is continuing due to rapid economic growth and high industrialization, but it is difficult to secure the position of industrial facilities on the land due to various problems such as lack of space on the land and opposition of local residents.

In addition to solving the problem of securing such a site, construction of offshore structure is being actively carried out in order to more actively utilize the oceans where rich mineral resources exist. Examples of such structures include incinerators, power plants, and offshore plants that are built on the coast. Among them, the offshore plant refers to the facilities necessary for the activities of excavation, drilling, production and storage of marine resources such as oil and gas.

In particular, the Gravity Based Structure (GBS), one of the offshore plants, can be used to load or unload liquefied petroleum gas (LNG), crude oil, etc., with its own weight fixed on the seafloor. For example, Korean Patent Publication No. 2013-0031032 discloses an example of a gravity based offshore structure.

Such conventional gravity-based offshore structures are usually constructed to include structures such as concrete and steel frame, and are fixed to the seabed by utilizing the force of gravity on the shallow sea.

However, if impacts such as suddenly changing waves and irregular earthquakes are constantly applied to the concrete structure, the concrete structure is locally destroyed and easily cracked. In addition, the concrete structure has a problem that the construction period is long, the construction cost is high, maintenance is difficult in case of breakage, and it is difficult to transport the structure or move it to the fixed position due to its large weight.

Patent Document 1: Korean Laid-Open Patent Application No. 2013-0031032 (published on Mar. 31, 2013)

The embodiment of the present invention is structurally safe in an extreme marine environment by preventing the deformation of the structure due to the pressure of the heavy body by dispersing the pressure applied to the seabed surface, Gravity type offshore structure and its installation method.

According to one aspect of the present invention, a gravity type offshore structure includes a bottom portion formed in a double hull structure using a metallic material and in contact with a bottom surface, a plurality of side wall portions vertically formed from the edges of the bottom portion, A hull comprising a deck portion and receiving a particulate mass having a specific gravity higher than that of the bottom portion and being fixed at a fixed position; And at least one cargo hold fixedly installed in the inside of the hull, wherein the bottom part has a plurality of compartments arranged in a horizontal lattice form at a lower part thereof for receiving the particulate weight injected from outside through a conveyance pipe, .

In addition, the bottom portion may be formed with maintenance spaces spaced apart from the lower portion of the cargo hold by a predetermined height above the plurality of compartments.

In addition, the deck part may include a hatch for exposing the gravity type offshore structure to the sea when the gravity type offshore structure is fixed, and for allowing the conveyance pipe to pass through the inside of the hull.

The compartments include a diaphragm interposed in a vertical direction between an outer shell adjacent to the seabed surface and an inner shell formed at a position opposite to the shell to face the bottom shell, A penetrating through hole and a cover covering the through hole may be formed.

The side wall part may include a ballast tank that divides the space between the outer wall and the inner wall into a plurality of partitions by a double wall surface extending in the vertical direction from the edge of the bottom part.

In addition, the side wall may be spaced a certain distance from the outer wall of the cargo hold installed in the inside of the hull so that the conveying pipe passing through the hatch of the deck portion may be formed as a space to be lowered into the bottom portion.

In addition, a wall surface stiffener having a horizontal groove may protrude from the inner wall surface of the side wall portion to support the outer wall and the inner wall.

According to another aspect of the present invention, there is provided a method for installing a gravity type offshore structure, comprising the steps of: a) forming a double hull structure using a metallic material to form a bottom portion in contact with the sea floor, a plurality of side walls vertically formed from the edge of the bottom portion, Moving a weighted offshore structure having a hull structure including a deck portion connecting the upper portions of the buoys to the installation site; b) injecting a particulate mass into the divided partial compartments of the bottom portion through a suction type transfer tube to secure a towing draft; c) filling the ballast tank formed in the side wall with seawater and descending to the bottom surface of the fixed position; And d) filling the remaining compartments of the bottom portion with the particulate mass to increase the gravity load so as to maintain the fixed position of the bottom.

In addition, in the step b) and the step d), the conveyance pipe is alternately inserted into the hull through the hatch disposed at a predetermined interval on the deck section using the barge and the heavy body injection equipment, Into the compartment.

When the gravity type offshore structure is moved after the step d), the particulate weight contained in the bottom portion of the bottom portion is extracted to the outside through the conveyance pipe, and the amount of seawater in the ballast tank is adjusted, The method comprising:

According to the embodiment of the present invention, a gravity type marine structure using a metallic material can be rigidly designed as a double wall structure, and its own weight can be maintained by accommodating the granular weight in the divided compartments of the hull bottom portion By dispersing the gravity load on the entire bottom surface portion, it can be easily fixed even in extreme marine environment.

In addition, when the gravity type offshore structure moves, the gravity type gravity weight contained in the bottom portion of the hull can be extracted and the amount of seawater in the ballast tank can be controlled to facilitate the rising and moving of the gravity type offshore structure.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing the internal structure of a gravity type structure of an improved weight receiving system.
2 is a perspective view schematically illustrating a gravity type offshore structure according to an embodiment of the present invention.
3 is an AA sectional view showing the internal structure of a gravity type offshore structure according to an embodiment of the present invention.
4 is a flowchart illustrating a method of installing a gravity type offshore structure according to an embodiment of the present invention.
FIG. 5 shows a state in which a particulate weight is injected into a compartment of a bottom part to secure a toe draft according to an embodiment of the present invention.
6 is an operation diagram illustrating a process of fixing a gravity type offshore structure to a sea floor according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise. Also, the terms " part, "" module," and " module ", etc. in the specification mean a unit for processing at least one function or operation and may be implemented by hardware or software or a combination of hardware and software have.

Now, a gravity type offshore structure according to an embodiment of the present invention will be described in detail with reference to the drawings.

Various types of gravity type structures have been developed in order to solve the problem of the conventional concrete type gravity type structure, and a structure of the LNG condensation terminal, which is one example of the gravity type structure developed by the Company, Explain.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing the internal structure of an improved gravity type gravity type structure. Fig.

Referring to FIG. 1, the improved gravity type structure has a double hull structure of a steel structure, and an LNG cargo hold is installed therein. The hull includes a bottom portion on which a water ballast tank (WBT) And a sidewall portion for receiving iron ore in the wing.

The improved gravity structure fills the iron ore tanks in the sidewall to secure a towing draft and fills the lower ballast tanks for initial positioning at the site to maintain a fixed position on the seafloor.

By loading the remaining iron ore on the side wall through the barge and conveyor, the gravity load is increased so that the position can be maintained even under external load conditions.

However, since the improved gravity type solution structure of FIG. 1 is easy to load iron ore from the upper part of the side wall part, iron ore is concentrated on the side wall part of both narrow side wings, so that a gravity load is concentrated on a part of the bottom surface. Therefore, under extreme environments such as earthquakes, there is a disadvantage that it is somewhat structurally unstable, such as subsidence in the ground.

Therefore, there is a problem that excessive excessive reinforcement is required on the seabed surface where the gravity load is concentrated before the gravity type structure is installed. In addition, a method of widening the width of the side walls of both wings is considered, but the increase of the width is due to many constraints such as the distance of the crane arm and the width of the dock when transporting heavy objects, .

Therefore, in the embodiment of the present invention, a gravity tank is disposed under the gravity type structure to accommodate the weight, so that the gravity load is dispersed throughout the bottom portion and the depth is increased, We propose an offshore structure and its installation method.

2 is a perspective view schematically illustrating a gravity type offshore structure according to an embodiment of the present invention.

2, a gravity type offshore structure 1 according to an embodiment of the present invention is formed of a double wall structure using a metal material and has a specific gravity (SG) higher than that of water ), Through which the self weight can be maintained and easily fixed to the sea floor. In the embodiment of the present invention, the granular weight 10 is generally made of iron ore. In the embodiment of the present invention, sand having a specific gravity lower than that of iron ore (SG = 5.2) . ≪ / RTI >

In addition, the pressure of the particulate weight 10 is dispersed in the various compartments 131 under the hull so that excessive pressure is not applied to the specific compartment 131, thereby effectively preventing deformation of the structure, It is possible to greatly enhance the stability of the structure even in an extreme environment such as an earthquake or the like.

Hereinafter, the detailed structure of the gravity type offshore structure 1 having such features will be described in detail with reference to FIG.

3 is a cross-sectional view taken along the line A-A of the internal structure of the gravity type offshore structure according to the embodiment of the present invention.

3, a gravity type offshore structure 1 according to an embodiment of the present invention includes a cargo hold 200 that is fixedly installed inside a hull 100 and a hull 100. As shown in FIG.

The hull 100 includes a bottom portion 130 in contact with the bottom surface of the lower portion of the ship 100, a plurality of side wall portions 120 formed perpendicular to the corners of the bottom portion 130, 110).

3, the shape of the hull 100 is not limited thereto. The shape of the hull 100 may be a polygon including a cube, a polygon including a part of a streamline, and other unshaped shapes such as a cylindrical shape. have. In addition, although FIG. 3 shows only one hold 200, the present invention is not limited thereto, and a plurality of hold spaces may be arranged in the ship 100 in parallel.

The deck part 110 forms the upper surface of the hull 100, and various various equipment such as a cabin can be installed.

For example, the deck part 110 may be provided with a treatment facility capable of directly treating the cargo stored in the cargo hold 200, such as a refining facility for refining gas or crude oil.

The deck part 110 is exposed above the sea floor when the gravity type offshore structure 1 is fixed and includes a hatch 111 disposed at a predetermined interval on the upper surface, 10 into the inside of the hull 100 through the hatch 111 and into the inside thereof. At this time, the transfer pipe 30 is guided to the position of each hatch 111 through the weight injecting equipment 20 provided with a suction pump for sucking the particulate mass 10 into the transfer pipe 30. The heavy body injection equipment 20 may be constructed of a crane capable of extending in a folding or folding manner.

The conveyance pipe 30 may be constructed of a hydraulic rubber pipe and sucks the granular weight 10 loaded on the side of the barge as shown in FIG. 1 and transfers the granular weight 10 to the bottom portion 130 inside the hull 100. At this time, the particulate weight 10 transferred to the bottom surface portion 130 and filling the compartments 131 is limited in the production of iron ore having the conventional SG = about 5.2 and the injection through the transport pipe 30 is considered , It can be replaced by a small, low-priced sand or SG = 2.5 iron ore of general size. Further, the material of the particulate weight 10 is not limited to this, and it is possible to fill the material having the characteristic that the specific gravity (SG) is higher than that of water and accumulates in the gravity direction in order to increase the force in the direction of gravity against the external force in the marine environment can do.

The side wall part 120 is a double wall surface extending vertically from the edge of the bottom surface part 130. The space between the outer wall 121 and the inner wall 122 is divided into a plurality of partitions 123 by a ballast tank 124 . Accordingly, the sidewall 120 may include a ballast pump, which is omitted in the drawing, to maintain the equilibrium of the hull 100 by introducing or discharging seawater into each ballast tank 124.

The inner wall 122 of the side wall part 120 forms a space spaced from the outer wall of the cargo hold 200 installed inside the hull 100 and the hatch 111 of the deck part 110 between the spaced spaces And the through-conveying pipe 30 is lowered to the bottom surface portion 130.

In addition, a wall stiffener 125 protrudes from the inner wall surface of the side wall 120 to effectively support the outer wall 121 and the inner wall 122 constituting the double wall surface.

A plurality of wall reinforcements 125 may be formed in a trapezoidal cross-sectional shape by being connected to each other continuously. Grooves 126 formed between neighboring wall stiffeners 125 disperse an external impact in the horizontal direction applied from the wind and waves outside the hull 100 to the entire sidewall portion 120, As shown in Fig.

At this time, the wall stiffener 125 having a trapezoidal cross-sectional shape is attached to a part of the ballast tanks 124 in order to further reinforce the gravity load by the granular weight 10 charged in the bottom portion 130 It can be smoothly lowered while being in contact with the wall stiffener 125 and uniformly loaded from the lower part of the ballast tank 124.

However, the wall stiffener 125 in the embodiment of the present invention is not limited to a trapezoidal cross-sectional shape, but a stiffener disposed in a T shape along each wall surface may be provided.

The bottom surface portion 130 may be a plate-like member extending in the horizontal direction forming the lower surface of the hull 100. The bottom surface portion 130 may include a plurality of compartments (131) and a maintenance space part (132) formed thereon.

The bottom portion 130 stably maintains the entire hull 100 in contact with the bottom surface, and is made of a high-strength metal material, so that the load of the hull 100 can easily be supported. At this time, a foundation work accompanied with a flattening operation for stably fixing the hull 100 may be performed on the bottom surface contacting with the bottom surface portion 130 when the gravity type offshore structure 1 is fixed.

The bottom part 130 can be made of special steel that minimizes corrosion or damage caused by seawater. For example, the bottom part 130 can be made of a special steel alloy such as molybdenum having a strong internal resistance. Also, the deck portion 110 and the side wall portion 120 may be made of the same special steel.

In the inside of the bottom portion 130, the particulate weight 10 having a specific gravity higher than that of water is filled to increase the weight of the entire hull 100. Therefore, not only the gravity type offshore structure 1 can be easily fixed to the fixed position on the coast, but also the structure of the ship 100 can be stably maintained even against strong waves, winds, and the like.

In addition, unlike the existing concrete structure, it is possible to prevent cracks and the like of the hull 100 from being caused by the special high strength corrosion-resistant steel.

The compartment 131 of the bottom face portion 130 is provided with a partition plate 131 interposed in the vertical direction on the double hull including an outer plate 131-1 which is in contact with the sea bottom and an inner plate 131-2 which is formed at a position facing the inside of the ship, -3). However, if necessary, the interval of the compartments 131-3 may be adjusted to appropriately adjust the size of the compartment 131. However, if the left and right sides of the hull 100 are symmetrical with respect to the center (center) of the hull 100, Size.

The inner plate 131-2 corresponding to the upper portion of each compartment 131 is formed with a through hole 131-4 and a cover 131-5 which are partially opened. Therefore, the conveyance pipe 30, which is lowered through the open hatch 111 of the deck part 110, can penetrate the through hole 131-4 and inject the particulate weight 10 into the compartments 131 have.

The bottom part 130 houses the particulate weight 10 injected through the conveyance pipe 30 into the plurality of divided compartments 131 so that the load caused by the particulate weight 10 is transmitted to the hull 100 ).

The cargo space 200 is a space for accommodating LNG, Crude Oil or other liquid or liquid cargo such that the lower portion of the cargo space 200 and the compartments 131 of the bottom portion 130 A maintenance space part 132 spaced apart by a predetermined height is formed.

The maintenance space part 132 is provided with an entrance (not shown) on a part of the wall surface of the cargo hold 200 so that an operator can access the cargo space 200. The operator can easily maintain the compartment 131 and the cargo hold 200 .

The maintenance space part 132 is provided not only with the compartment 131 but also with the side wall part 120 to provide a thermal insulation function for shielding heat transmitted from the outside to the cargo window 200, And the pressure of the granular weight 10 received in the compartment 131 can be prevented from being directly transmitted to the cargo hold 200. [0054] Through such a function, the safety of a cargo such as LNG and crude oil accommodated in the cargo hold 200 can be enhanced.

The cargo hatch 210 may be formed at the upper and lower portions of the cargo hold 200 to allow the conveyance pipe 30 to pass through the compartment 131 in the center of the hull to inject the granular weight 10 .

At this time, a rubber bellows may be installed in the cargo hatch 210 to prevent the inside of the cargo window 200 from being contaminated through a hole through which the transfer pipe 30 passes.

Meanwhile, a method of installing the gravity type offshore structure 1 according to the embodiment of the present invention will be described with reference to FIGS. 4 to 6 below.

4 is a flowchart illustrating a method of installing a gravity type offshore structure according to an embodiment of the present invention.

Referring to FIG. 4, a method for installing a gravity type offshore structure 1 according to an embodiment of the present invention is a method for installing a gravity type offshore structure 1 in a state in which a grained weight 10 is not accommodated And moves to the installation site through the barge or tug (S101).

When the gravity type offshore structure 1 arrives at the installation site, the granular weight 10 is injected into the divided part of the compartment 131 of the bottom part 130 of the hull 100 through the suction type feed pipe 30, A towing draft is secured (S102).

FIG. 5 shows a state in which a particulate weight is injected into a compartment of a bottom part to secure a toe draft according to an embodiment of the present invention.

At this time, the gravity type offshore structure 1 is formed by partially injecting the granular weight 10 into only some of the compartments 131 symmetrical with respect to the center of the bottom portion 130 to ensure the towing draft, Can be stabilized. This hull stabilization operation may be performed before the step S101 in which the gravity type offshore structure 1 is moved through the tugboat.

When the gravity type offshore structure 1 reaches the installation position in the site, the ballast tank 124 of the side wall portion 120 of the hull 100 is filled with seawater and descends to the bottom surface of the fixed position (S103).

6 is an operation diagram illustrating a process of fixing a gravity type offshore structure to a sea floor according to an embodiment of the present invention.

6, the left side (A) shows a state in which the gravity type offshore structure 1 is lowered due to an increased load by filling seawater in the ballast tanks 124 of both side wall portions 120. At this time, the descended gravity type offshore structure 1 can be fixed to the seabed surface against general external force even with the seawater filled in the ballast tank 124 alone.

The gravity type offshore structure 1 is then filled with the particulate weight 10 in the entire compartment 131 of the bottom portion 130 as shown in the right side of FIG. The gravity load is increased (S104).

2 and 3, the conveyance pipe 30 is alternately inserted into the hull 100 through the barge and the heavy-weight injecting equipment 20 so that the granular weight 10 is inserted into each compartment 131, .

4, when the gravity type marine structure 1 fixed to the sea floor is moved to another place, the method of FIG. 4 is reversed to move the particulate mass in each compartment 131 to the conveying pipe 30 The ballast tank 124 is empty and the hull 100 can be moved up by moving it.

As described above, according to the embodiment of the present invention, it is possible to design a gravity type marine structure using a metal material or the like as a double wall structure, and to maintain the weight of the marine structure by accommodating the granular weight in the divided compartments of the hull bottom portion In addition, since the gravity load is distributed over the entire bottom surface, it is possible to fix the gravity load easily even in an extreme marine environment.

In addition, when the gravity type offshore structure moves, the gravity type gravity weight contained in the bottom of the hull can be extracted and the gravity type offshore structure can be easily raised by controlling the amount of seawater in the ballast tank.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications are possible.

For example, in the above-described embodiment of the present invention, the gravity load 10 is filled in all the compartments 131 of the bottom portion 130 to increase the gravity load. However, the present invention is not limited to this, The gravity load 10 can be further charged by further filling the granular weight 10 even in some compartments (ballast tanks) of the side wall part 120 when a load is needed more.

In addition, the gravity load of the entire hull 100 can be further increased by increasing the depth of the bottom surface portion 130 to increase the filling amount of the particulate weight 10. [

Therefore, there is an advantage that the stability at a site with a deep sleep of 15 m or more in general can be raised to a high level.

The embodiments of the present invention are not limited to the above-described apparatuses and / or methods, but may be implemented through a program for realizing functions corresponding to the configuration of the embodiment of the present invention, a recording medium on which the program is recorded And such an embodiment can be easily implemented by those skilled in the art from the description of the embodiments described above.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

10: Particulate weight 20: Heavy weight injection equipment
30: Transfer pipe 1: Gravity type offshore structure
100: hull 110: deck section
111: Hatch 120: Side wall part
121: outer wall 122: inner wall
123: partition wall 124: ballast tank
125: stiffener 126: groove
130: bottom part 131: compartment
131-1: outer plate 131-2: inner plate
131-3: diaphragm 131-4: through hole
131-5: cover 132: maintenance space part
200: Cargo hold 210: Cargo hatch

Claims (10)

And a deck portion formed in a double hull structure using a metallic material and contacting the bottom surface, a plurality of side wall portions formed vertically from the edge of the bottom portion, and a deck portion connecting the upper portions of the side wall portions, A hull which holds the particulate weight and is fixed at a fixed position; And
And at least one cargo hold fixedly installed inside the hull,
Wherein the bottom portion has a plurality of compartments arranged in a horizontal lattice shape below the bottom portion to receive the particulate masses injected from the outside through a transfer pipe. The method according to claim 1,
Wherein the bottom portion comprises:
And a maintenance space part spaced apart from the lower part of the cargo hold by a predetermined height is formed in the upper part of the plurality of compartments. The method according to claim 1,
The deck portion
A gravity-type offshore structure including a hatch for exposing the gravity type offshore structure to the sea floor when the gravity type structure is fixed and for allowing the conveyance pipe to penetrate into the hull. The method according to claim 1,
Wherein said compartment comprises:
And a diaphragm interposed in a vertical direction between a double sheath including an outer sheath in contact with the seabed surface and an inner sheath formed in a position opposite to the sheath inward,
And a cover covering the through-hole and the through-hole through which the conveyance pipe penetrates is formed on the upper surface of each compartment. The method according to claim 1,
The side-
And a ballast tank dividing a space between the outer wall and the inner wall into a plurality of partition walls by a double wall surface extending in a vertical direction from a corner of the bottom wall portion. The method according to claim 1,
The side-
Wherein the inner wall of the double wall surface is spaced apart from the outer wall of the cargo hold provided inside the hull so that the conveyance pipe penetrating the hatch of the deck portion forms a space to be lowered into the bottom portion. The method according to claim 6,
And a wall surface reinforcement projecting in a horizontal direction groove protrudes from the inner wall surface of the side wall portion to support the outer wall and the inner wall. a) a hull structural weighted offshore structure including a bottom portion formed in a double hull structure using a metallic material and in contact with the sea bottom surface, a plurality of side wall portions formed vertically from corners of the bottom portion, and a deck portion connecting upper portions of the side wall portions to each other To the installation site;
b) injecting a particulate mass into the divided partial compartments of the bottom portion through a suction type transfer tube to secure a towing draft;
c) filling the ballast tank formed in the side wall with seawater and descending to the bottom surface of the fixed position; And
d) filling the remaining compartments of the bottom portion with the particulate mass to increase the gravity load so as to maintain the fixed position of the bottom of the seabed
The method comprising the steps of: 9. The method of claim 8,
The steps b) and d)
And a step of injecting the gravity weight into the compartments by alternately inserting the conveyance pipe into the hull through a hatch disposed at a predetermined interval on the deck section using a barge and a heavy body injecting equipment to install the gravity type offshore structure Way. 9. The method of claim 8,
After the step d)
Further comprising the step of raising the gravity type offshore structure by controlling the amount of seawater in the ballast tank by extracting the particulate weight contained in the bottom portion of the gravity type offshore structure through the conveyance pipe, How to Install Offshore Structures.

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