KR20150131708A - A Marine Structure - Google Patents

Abstract

An offshore structure is disclosed in which a door pool is formed on the hull.
The offshore structure includes a recess formed on the door frame, and the recess bottom portion or the recess wall portion includes a depression.

Description

{Marine Structure}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offshore structure, and more particularly, to an offshore structure configured to disperse the offshore energy of a seawater flow occurring in a recess.

Along with the development of submarine mining technology, drilling lines have been developed with drilling facilities suitable for marginal field or deep sea oil development. Conventional submarine drilling has been mainly used for a rig ship or a rigid platform for underwater drilling that can be sailed only by another tugboat and performs submarine drilling with anchorage at one point of the sea using a mooring device. In recent years, a drill ship, which is equipped with advanced drilling equipment and manufactured in the same form as a ship, has been developed and used for deep sea drilling.

In such an offshore structure for underwater drilling, a moon pool is formed for accessing various equipment for drilling. The moon pool is a rectangular parallelepiped or cylindrical space formed so as to penetrate vertically between the deck and the bottom of the hull. to be. In addition, an offshore structure for drilling and other drilling forms an auxiliary space in the interior of the drum to temporarily lower the drilling equipment, which is called a recess.

However, in the conventional drill ship, there is a problem that the crew working on the drilling equipment or the hull installed on the top of the drum can be damaged by the seawater flow generated in the recess.

Hereinafter, referring to FIG. 1, a principle of generating a large sea water flow in the recess will be described.

1 is a cross-sectional view partially showing a drillhose in which a recess in a conventional door is formed.

Sea waves generated by the wind are always present outside the hull 1 and seawater in the interior of the hatchery 2 receives the energy from the sea waves outside the hull 1 to generate the wave 5a.

Sea waves can be classified into deep-sea waves and deep-sea waves depending on the relationship between depth and wavelength. Sea waves in the case where the water depth is deeper than one-half of the wavelength is called deep water waves and the sea depth is shallower than one- Is called a deep sea wave.

The deep-sea waves are also called longwaves, and water particles are subjected to elliptical motion by the frictional force of the seabed since they are affected by the seabed. The propagation velocity of the shallow wave is irrelevant to the wavelength and is related only to the depth of water. Therefore, the progressive velocity of the shallow wave slows down as the depth of water becomes shallower. As the propagation speed of the deep sea wave slows down, the kinetic energy that is reduced changes to the potential energy, so that as the coastal wave approaches the coast, the wavelength becomes shorter and the wave height becomes higher.

For example, in the case of a tsunami that has a characteristic of shallow waves, if a tsunami occurs with an extremely long wavelength of 100 to 200 kilometers in the distant sea due to an earthquake, However, as the tsunami approaches the shore, the depth of the tsunami becomes shallower, slowing down the process, reducing the wavelength to several kilometers, and increasing the tsunami to tens of meters.

When the wave 5a generated in the interior space 2 has a characteristic of a deep sea wave, the depth of water in the recess 3 becomes shallow, so that the sea wave 5b in the recess 3, . The wave 5b in the recess 3 having a high crest causes a large seawater flow and the wave 5b in the recess 3 rises on the inside wall surface 2b of the inside of the recess 3, (4) damage to crew members who are working on the hull (1).

Hereinafter, the inside wall surface 2b of the inside wall surface 2b refers to the inside wall surface of one side of the inside wall which is connected to the recess 3. [

As a technique for reducing seawater flow inside a conventionally recessed construction, there is a floating structure of Korean Patent Laid-Open No. 10-2011-0027404. The hull includes a hull having a door pool for drilling, a recess formed at a lower end of a stern side of the door pool, and a damping plate installed at a side of the stern of the door pool.

However, such a conventional floating structure does not provide a solution to the fundamental cause of the large sea water flow, but merely provides a structure for passively reducing the sea water flow, There was a limit to preventing damage.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problem of the conventional art and to solve the cause of generation of a wave having a high wave height in a recess through a change in the structure of a bottom surface of a recess, The purpose of the present invention is to provide an offshore structure that is constructed to prevent damages caused by drilling equipment or crew members from being caused by sea waves due to changes in the structure of the ship.

According to an aspect of the present invention, there is provided an offshore structure having a doorpost formed on a hull, comprising a recess formed on the doorpath, wherein the recess bottom wall portion or the recess wall portion includes a depression , Marine structures are provided.

The recess bottom portion and the recess wall portion may all include depressions.

The recess formed in the recess wall portion may be connected to the recess formed in the recess bottom portion.

And a depression formed in the recess bottom portion may be formed on the recess wall portion side.

The depressed portion formed in the recess bottom surface may include an inclined surface that deepens the depth of the seawater in the compartment so that the recessed portion is directed toward the recess wall portion.

The recess formed in the recess bottom wall portion or the recess bottom wall portion may have a length equal to the width of the door frame.

The recess formed in the recess wall portion may include a damper on an upper portion or a lower portion.

The recess formed in the recess wall portion may include a damper on the upper and lower sides.

According to another aspect of the present invention, there is provided a method of drying an offshore structure for preventing damages caused by seawater flowing in a door frame, the method comprising: forming a recess on the door frame; And forming a depression in the recess bottom wall portion or the recess wall portion.

According to the marine structure of the present invention, it is possible to mitigate the phenomenon of generation of a sea wave having a large wave height in the recess even if the sea wave inside the interior of the interior has a characteristic of a shallow wave due to a change in the structure of the bottom surface of the recess. In addition, even if seawater flow occurs in the doorpath through the change in the structure of the wall of the recess, the seawater can be prevented from reaching the drilling equipment or the upper part of the hull.

As described above, according to the marine structure of the present invention, it is possible to prevent damage to the drilling equipment or a risk to the crew due to the large sea water flow in the recess due to a change in the structure of the bottom surface portion or the wall portion.

1 is a cross-sectional view partially showing a drillhose in which a recess in a conventional door is formed.
2 is a schematic structural view showing an offshore structure according to a first preferred embodiment of the present invention.
3 is a schematic structural view showing a marine structure according to a modification of the first preferred embodiment of the present invention.
FIG. 4 is a schematic structural view showing an offshore structure according to a second preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The offshore structures of the following embodiments may be all vessels for subsea drilling in which recesses are formed in a portal, such as a league line, a drill ship, and the like. In addition, the following examples can be modified in various forms, and the scope of the present invention is not limited to the following examples.

2 is a schematic block diagram illustrating an ocean structure according to a first preferred embodiment of the present invention.

Referring to Figure 2, the offshore structure of the present embodiment comprises a platform 2; And a recess 3 formed in the door frame 2 and having a depression 3a at the bottom surface 3d.

The door frame 2 is formed to penetrate the hull 1 in the vertical direction so that various drilling rigs 4 for the drilling operation at the seabed can enter and exit, and can have a rectangular parallelepiped shape or a cylindrical shape.

The recess 3 is formed in the interior of the door 2 to provide a place where the drilling rig 4 can be temporarily lowered. In general, the recess 3 is located below the aft- The position in which the recess 3 of the invention is formed is not limited to being below the aft-side sea level.

2, the recess bottom portion 3d of the present embodiment includes a depressed portion 3a formed on the side of the recess wall portion 2a so as to form a step with the recess bottom portion 3d, The depth of the sea water above the depressed portion 3a is deepened by forming the depressed portion 3a on the bottom surface portion 3d.

When the depth of the sea water above the depression (3a) is deepened, even if the sea wave inside the door pool (2) has a characteristic of a deep sea wave, the progress speed of the deep sea wave accelerates as the depth of water deepens, The traveling speed of the slow wave is accelerated as the wave moves toward the recess wall portion 2a. When the propagation velocity of the wave is increased, the potential energy of the wave is converted into kinetic energy, so that the phenomenon of generating a wave having a large wave height in the recess 3 on the recess wall 2a can be alleviated.

2, the width w1 of the side portion of the depression 3a formed in the recess bottom portion 3d is about 5% to 50% of the width w2 of the side portion of the recess bottom portion 3d . If the width w1 of the side portion of the depressed portion 3a is less than about 5% of the width w2 of the side portion 3d of the bottom portion 3d, the effect of reducing the seawater flow may be insignificant, It may be difficult to place the drilling rig 4 down in the recess 3 when the width w1 exceeds approximately 50% of the side portion width w2 of the bottom surface portion 3d.

The height h of the side surface of the depressed portion 3a formed in the recess bottom portion 3d is set to be smaller than the height h of the recessed bottom surface portion 3d formed in the recess bottom surface 3d so as to effectively reduce the seawater flow in the recess 3. [ And may have a length substantially equal to the width w1 of the side portion of the depression 3a.

FIG. 3 is a schematic structural view showing a marine structure according to a modification of the first preferred embodiment of the present invention.

3, an offshore structure according to the present embodiment includes a platform 2, which is similar to the offshore structure according to the first embodiment; And a recess 3 formed in the door frame 2 and having a depression 3a at the bottom surface 3d. However, the depressed portion 3a of the present embodiment includes the inclined surface 3b that deepens the depth of the seawater in the interior of the door 2 as it goes toward the recess wall 2a.

2 and 3, when the depressed portion 3a is formed so as to form a step with the recess bottom portion 3d as in the first embodiment, the abrasion due to the seawater flow is concentrated on the edge portion 3c . Therefore, the depression 3a according to the modification of the first embodiment includes the inclined face 3b that deepens the depth of the sea water in the interior of the door 2 as it goes toward the recess wall 2a, The wear of the edge 3c portion of the wafer W can be reduced.

FIG. 4 is a schematic configuration view showing an offshore structure according to a second preferred embodiment of the present invention.

Referring to Fig. 4, the marine structure of the present embodiment, like the marine structure according to the first embodiment, comprises a portal 2; And a recess 3 formed in the door frame 2 and having a depression 3a at the bottom surface 3d. The recess bottom portion 3d of the present embodiment is formed on the side of the recess wall portion 2a so as to form a step with the recess bottom portion 3d similarly to the recess bottom portion 3d according to the first embodiment And a depressed portion 3a.

However, the recess 3 of the present embodiment includes the depressed portion 3a on the wall portion 2a. A lower portion of the depressed portion 3a formed in the recessed wall portion 2a is connected to a depressed portion 3a formed in the recessed bottom surface portion 3d and a recessed portion formed in the recessed wall portion 2a The upper portion of the recessed portion 3a is formed such that the seawater strikes when a seawater flow occurs in the interior space 2. The depressed portion 3a formed in the recessed wall portion 2a prevents the seawater from entering the drilling equipment 4, (1) to prevent it from reaching the upper part.

A damper 6 is provided on an upper portion or a lower portion of the depression 3a formed in the recess wall 2a of the present embodiment so as to mitigate the impact of the hull 1 due to seawater flow in the interior of the door pool 2. [ Can be installed. The damper 6 may be installed on both the upper and lower portions of the depressed portion 3a formed in the recess wall portion 2a.

3 and 4, a marine structure according to a modification of the second preferred embodiment includes a recessed bottom portion 3d and a depression 3a formed in the wall portion 2a, In addition, it may include an inclined surface 3b for reducing the wear of the edge 3c of the depressed portion 3a of the recess bottom portion 3d.

2 to 4, depressions 3a formed in the recess bottom surface portion 3d or the wall surface portion 2a of the preferred embodiment of the present invention have a length substantially equal to the width of the door frame 2 .

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. It is.

1: Hull 2:
2a: recess wall part 2b: inner side wall of the interior space
3: recess 3a: depression
3b: slope 3c: corner
3d: recess bottom 4: drilling rig
5a, 5b: wave 6: damper

Claims (9)

As an offshore structure in which a door grass is formed on the hull,
And a recess formed in the upper portion of the door frame,
Wherein the recess bottom portion or the recess wall portion includes a depression. The method according to claim 1,
Wherein the recess bottom portion and the recess wall portion both include depressions. The method of claim 2,
And a depression formed in the recess wall portion is connected to a depression formed in the recess bottom portion. The method according to any one of claims 1 to 3,
And a depression formed in the recess bottom portion is formed on the side of the recess wall portion. The method according to any one of claims 1 to 3,
Wherein the depression formed in the recess bottom surface includes an inclined surface that deepens the depth of the sea water in the compartment toward the recess wall surface. The method according to any one of claims 1 to 3,
Wherein a recess formed in the recess bottom surface portion or the recess wall portion is formed to have the same length as the width of the door frame. The method according to any one of claims 1 to 3,
Wherein the recess formed in the recess wall portion includes a damper on an upper portion or a lower portion. The method according to any one of claims 1 to 3,
Wherein the recess formed in the recess wall portion includes a damper on the upper portion and a damper on the lower portion. As a method for drying an offshore structure to prevent damages due to seawater flow generated in a door frame,
Forming a recess in the upper portion of the door frame; And
And forming a depression in the recess bottom wall portion or the recess wall portion.

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