KR102653589B1 - Method For Supporting A Cutted Pipe On Disjointing A Construction Comprised Of Large-caliber Pipes - Google Patents

Abstract

The present invention relates to a method of supporting a steel pipe that can prevent movement of a cut steel pipe during dismantling of a structure such as an offshore structure made of steel pipe.
The present invention relates to a steel pipe support method for preventing movement of the upper structure by temporarily supporting the separated steel pipes in a disassembly method of separating the upper structure from the lower structure by cutting a plurality of steel pipes, which can be inserted into the steel pipe. A rope is connected to one end of a slip stopper made of a diameter, and the slip stopper is inserted into the separated steel pipe among the steel pipes while holding the other end of the rope, and the slip stopper is placed at the steel pipe cutting position. do.

Description

{Method For Supporting A Cutted Pipe On Disjointing A Construction Comprised Of Large-caliber Pipes}

The present invention relates to a method of supporting cut steel pipes during dismantling of marine structures made of large-diameter steel pipes. More specifically, the present invention relates to a method of supporting cut steel pipes during dismantling of structures such as marine structures made of large-diameter steel pipes, ensuring the stability of the cut steel pipes up to the stage before salvage. This relates to a method of supporting steel pipes that can prevent accidents.

In order to produce oil or gas on the seabed, a production facility is needed, and the production facility is installed on an offshore structure. Offshore structures equipped with such production facilities have developed into various forms depending on water depth and function.

In general, offshore structures for oil production are classified into shapes that change depending on the water depth, and are divided into fixed offshore structures, flexible offshore structures, and floating offshore structures. Among these, fixed marine structures have the advantage of being fixed to the seafloor by piles or their own weight, so they do not move due to waves or wind during work. However, since fixed marine structures must be connected by a rigid body from the water surface to the sea floor, as the water depth increases, it becomes difficult to put them into practical use due to disadvantages such as excessive drying costs.

These fixed marine structures can be further classified into jacket type, gravity type, and deck lifting type.

Jacket-type structures are secured by piles cast into the seafloor. In other words, the main leg of the jacket is supported by wrapping the pile, so it is called a jacket. The jacket is mainly manufactured in the form of a lattice truss by welding steel pipe members. A deck is installed on the top of the jacket, and production equipment and living facilities, etc. are mounted there.

When these structures reach the end of their useful life or become unusable due to damage from accidents or natural disasters, dismantling is necessary. In general, the design life cycle of offshore structures is around 25 years, and there are currently more than 10,000 offshore structures installed around the world to develop oil or gas, and about 95% of them are fixed steel jacket platforms. It is known as

Dismantling of marine structures largely consists of preparation work and removal work and may be accompanied by a recycling process.

Preparatory work consists of well rupture, removal of contaminants, platform cleanup work, and pipe cleaning, and removal work includes conductor removal (see Figure 1a), superstructure removal (see Figure 1b), riser removal (see Figure 1c), and jacket. It consists of removal of the superstructure (see Figure 1d, this work is carried out in parallel with the structure removal work) and removal of the jacket substructure (see Figure 1e). And the structures collected in this way can be disposed of as scrap metal or recycled into artificial reefs, fish farms, marine amusement parks, wind power plants, etc.

The removal operation involves cutting the structure, and the underwater cutting operation in the dismantling operation occupies a very important position as a preliminary process for the lifting operation of the cut object.

As shown in FIG. 1b, in order to remove the superstructure, the legs of the structure are cut sequentially. Two of the four legs are cut, and when the third and fourth legs are cut, the superstructure is damaged by waves or wind. It may move or even fall. In addition, if the upper structure was left separated from the lower structure during lifting, stability was not secured during lifting, making the lifting operation difficult.

Therefore, in order to ensure stability during cutting and lifting operations of marine structures, the cut leg must remain in its correct position until lifting, but this phenomenon has not been considered so far.

Moreover, this problem can be applied not only to offshore structures but also to the dismantling of grid-type steel pipe structures installed on land.

Korean Patent Publication No. 10-2016-0068063 (published on June 15, 2016)

The present invention was developed in consideration of the above problems, and the purpose of the present invention is to ensure the stability of cut steel pipes from various external forces such as waves and currents until the stage before salvage during the dismantling of structures such as marine structures made of steel pipes. The purpose is to provide a support method for steel pipes that can prevent accidents.

According to the characteristics for achieving the above-mentioned purpose, the method of supporting a steel pipe temporarily supports the separated steel pipes in a dismantling method of cutting a plurality of steel pipes and separating the upper structure from the lower structure to control the behavior of the upper structure. In the method of supporting a steel pipe to prevent, a rope is connected to one end of a slip stopper having a diameter that can be inserted into the steel pipe, and the slip stopper is separated from the steel pipe while holding the other end of the rope. The slip stopper is inserted into the inside of the steel pipe and placed at the position where the steel pipe is cut.

In addition, the steel pipe support method according to the present invention is a steel pipe support method that prevents movement of the upper structure by temporarily supporting the separated steel pipes in the disassembly method of cutting a plurality of steel pipes to separate the upper structure from the lower structure. In the method, a first rope is connected to one end of a slip stopper having a diameter that can be inserted into the steel pipe, a second rope connected to the first rope is connected to a crane or a third rope connected to the crane, and a hook is attached to the end. A first step of connecting the fourth rope on which is mounted to the first rope; A second step of inserting the slip stopper into the steel pipe, attaching the hook of the third rope to the tip of the steel pipe, and then dismantling the second rope from a crane or the third rope; A third step of connecting one end of a fifth rope having a length corresponding to the cut position of the steel pipe to the first rope or the second rope and mounting the other end of the fifth rope to a crane or a third rope; A fourth step of dismantling the hook of the fourth rope from the end of the pipe by lifting the crane; and a fifth step of lowering the crane so that the central portion of the slip stopper is placed at the cutting position of the steel pipe.

At this time, in the first step, a tugger for manipulating the hook is fastened to the hook, a support rope connected to the crane is hung on the hook, and the fourth rope is pulled upward together with the hook. It can be included.

And in the first step, it further includes the step of mounting a hydraulic cutter capable of cutting the first rope on one end of the slip stopper and extending a hydraulic hose connected to the hydraulic cutter to the outside of the steel pipe, In the fifth step, the step of operating the hydraulic cutter through the hydraulic hose to cut the first rope connected to the slip stopper disposed at the cutting position of the steel pipe may be further included.

At this time, piles are placed inside the steel pipe to support the lower structure on the ground, and the upper pile cut along with the steel pipe is cut in advance, thereby forming a step at the steel pipe cut site, and the slip stopper is placed on the step. To enable seating, the upper part may be provided with a relatively larger diameter than the lower part.

According to the steel pipe support method according to the present invention, there is an advantage in preventing accidents by ensuring the stability of the cut steel pipe up to the stage before salvage during dismantling of a structure such as an offshore structure made of steel pipe.

In addition, according to the present invention, by fixing the cut structure at sea using the inside of the structure, underwater work can be minimized, which has the advantage of reducing the cost and time for dismantling work.

Figure 1 is a diagram showing the general marine structure dismantling work in order,
Figure 2 is a flow chart showing the steel pipe support method according to the present invention;
3 to 20 are views explaining each detailed step of the method for supporting a steel pipe according to the present invention.

The features and advantages of the present invention can be more clearly understood by referring to the embodiments illustrated in the accompanying drawings.

The application of the present invention is not limited by the configuration and arrangement of components described in the embodiments of the present invention or shown in the drawings. The present invention may be implemented in different embodiments and performed in various ways. Additionally, the expressions and predicates used in the embodiments regarding terms such as orientation of a device or element, etc. are merely used to simplify the description of the invention and do not indicate or imply that the device or element involved should simply have a particular orientation. No. For example, terms such as “first” and “second” are used in the examples and claims to describe the present invention, but these terms are not intended to indicate or imply relative importance or intent.

In addition, terms or words used in the specification and claims should not be construed as limited to their usual or dictionary meanings, and the inventor should use the technical idea of the present invention to explain the terms and concepts of the invention in the best way. It must be interpreted as written based on the corresponding meaning and concept.

Therefore, the present invention is not limited to the presented embodiments, and is understood by those skilled in the art to which the present invention pertains, within the technical spirit of the present invention and the technical equivalents described in the claims below. Various modifications and changes are possible.

In the following, the present invention will be described in detail with reference to the attached drawings.

Figure 2 is a flowchart showing a method for supporting a steel pipe according to the present invention, and Figures 3 to 20 are diagrams explaining each detailed step of the method for supporting a steel pipe according to the present invention.

As shown, the steel pipe support method according to the present invention prevents the movement of the upper structure by temporarily supporting the separated steel pipes in the dismantling method of separating the upper structure from the lower structure by cutting a plurality of steel pipes (P). In the steel pipe support method, a rope is connected to one end of a slip stopper (10) having a diameter that can be inserted into the steel pipe, and the slip stopper (10) is held while the other end of the rope is held. It relates to a method of inserting the slip stopper (10) into a separated steel pipe and placing the slip stopper (10) at the steel pipe cutting position.

In more detail, as shown in FIGS. 1A to 1E, it relates to a method of supporting a steel pipe used for dismantling heavy objects such as marine structures. In order to dismantle the marine structure, the upper structure and lower structure are cut and a crane ( When lifted and removed using C), the cut part may move or even fall due to waves or wind. To prevent this, a slip stopper is used to safely support the cut upper structure.

Therefore, in the steel pipe support method according to the present invention, movement of the upper structure may occur when cutting the third and fourth legs after cutting two legs in a structure consisting of four legs, so the first two legs are cut. It is preferable that it is later inserted into the steel pipe (P) forming the leg to support the cut portion.

If the structure consists of three legs, after cutting one leg, the steel pipe support device according to the present invention can be inserted into the steel pipe of the cut leg. As such, the timing at which the steel pipe support device according to the present invention is used may be determined depending on the characteristics of the structure and the working environment, and is not particularly limited.

In addition, when the offshore structure is a jacket-type structure, the structure is fixed by piles (PL) cast on the sea floor, and the legs surround the piles (PL). This leg cutting operation is performed in the order of cutting a specific location, first removing the pile (PL) at the top of the location, and then removing the upper structure including the leg.

The steel pipe support method according to the present invention outlined above will be described in detail based on FIGS. 3 to 20.

Figure 3 shows a slip stopper 10 connected to the crane C with a rope. As shown, the slip stopper 10 has a cylindrical shape with a constant length, and is provided with inclined surfaces 11 and 12 whose front and rear ends gradually become narrower to facilitate entry and exit from the steel pipe. Although not clearly shown in the drawing, an anchor shackle (hereinafter referred to as 'first shackle 31') for fastening a rope may be mounted on the top of the slip stopper 10.

Then, the rope is hung through the shackle. The type of the rope is not particularly limited, but in this embodiment, a wire rope sling manufactured to lift a large amount of heavy material may be used. Rings are formed at both ends of this wire rope sling, so it can be connected to another sling through an anchor shackle. Also, in this embodiment, unless specifically mentioned, 'rope' means 'wire rope sling'.

The rope (hereinafter referred to as 'first rope 21') passes through the first shackle 31, and the rings at both ends are connected to another shackle (hereinafter referred to as 'second shackle 32'), Another rope (hereinafter referred to as 'second rope 22') is connected to the second shackle 32, and the second rope 22 is a rope mounted on the crane C (hereinafter referred to as 'third rope ( 23)') through a shackle (hereinafter referred to as '3rd shackle (33)'). In addition, the third rope 23 is mounted on a shackle (hereinafter referred to as the 'fourth shackle 34') mounted on the crane C.

In addition, a rope (hereinafter referred to as 'fourth rope 24') equipped with a first hook 24a at the end is mounted on the second shackle 32. A retractor 24b (tugger) for manipulating the hook is fastened to the first hook 24a, and the retractor is made of wire and is placed outside the steel pipe. At this time, the fourth rope 24 may be in the form of a sling, but may also be configured as a wire grommet.

Then, the support rope 24c connected to the loop of the second rope 22 is hung on the first hook 24a to pull up the hook and place it in a position where it is easy to manipulate the hook.

In addition, a hydraulic cutter 40 capable of cutting the first rope 21 is mounted on one end of the slip stopper 10, and a hydraulic hose 41 is extended to the hydraulic cutter 40 to cut the hydraulic hose 41. ) can be placed outside the steel pipe. In order to cut the first rope 21 in this way, the hydraulic cutter 40 can be mounted in the middle of the first rope 21 passing through the two first shackles 31 at the top of the slip stopper 10. there is. In addition, the hydraulic hose 41 may be tied to the second rope 22 with a separate wire and extended to the outside.

FIG. 4 shows a state in which the slip stopper 10 mounted on the crane C in FIG. 3 is inserted into the steel pipe. It is preferable that the slip stopper 10 has a diameter that can be inserted into the steel pipe (P), and that its outer surface has a diameter that can be disposed adjacent to the inner periphery of the steel pipe.

Figures 5 to 7 show the process of connecting a longer rope (hereinafter referred to as the 'fifth rope 25') between the second rope 22 and the third rope 23 fastened in Figure 1. there is. First, in Figure 5, in order to release the coupling between the second rope 22 and the third rope 23, the first hook at the end of the fourth rope 24 is fastened to the tip of the steel pipe and the slip stopper 10 is connected to the steel pipe (P). It is hung inside. And as shown in FIG. 6, the connection between the second rope 22 and the third rope 23 is released. At this time, if the second rope 22 is dismantled from the third shackle 33, the second rope 22 and the third rope 23 can be separated.

The fifth rope 25 is fastened between the separated second rope 22 and the third rope 23 as shown in FIG. 7. At this time, after fastening the 5th rope 25 to the 3rd shackle 33 connected to the 3rd rope 23, the shackle connected to the 5th rope 25 (hereinafter referred to as the '5th shackle 35') Fasten the second rope (22). And the third shackle (33) is equipped with a rope (hereinafter referred to as 'sixth rope (26)') having a second hook (26a) mounted at the end like the fourth rope (24), and the hook is equipped with a retractor. It can be hung on the crane (C) by fastening (26b) and hanging the support rope (26c).

Also, at this time, the hydraulic hose 41 can be connected to the hose reel 42 (hose reel) through an umbilical connection.

When the length of the rope is increased through this process, as shown in Figure 8, the crane (C) is raised to release the first hook that is hanging the slip stopper (10) on the end of the steel pipe, and then, as shown in Figure 9, the hook is Dismantle the mounted fourth rope (24) from the second shackle (32).

In such a state, as shown in Figure 10, the crane (C) is lowered and the slip stopper (10) is additionally inserted into the steel pipe (P). However, if the slip stopper 10 does not reach the cut part of the steel pipe even with the length increased by the 5th rope 25, an additional rope (hereinafter referred to as the '7th rope 27') is connected to the 3rd rope. A process of separation and insertion is performed between (23) and the fifth rope (25) or between the third rope (23) and the crane (C). That is, as shown in FIG. 11, in this embodiment, the second hook mounted on the sixth rope 26 is hung on the tip of the steel pipe, and then, as shown in FIG. 12, the third rope 23 is separated from the crane C. One end of the 7th rope (27) is fastened to the third rope (23), and the other end of the 7th rope (27) is fastened to the crane (C). At this time, a shackle (hereinafter referred to as 'sixth shackle 36') may be additionally installed to connect the seventh rope 27 and the third rope 23.

In this way, when the length of the rope increases, as shown in FIG. 13, the crane C is raised to dismantle the second hook 26a of the sixth rope 26 from the tip of the steel pipe (FIG. 14), and as shown in FIG. 15. , lower the crane (C) so that the slip stopper (10) reaches the cut part of the steel pipe.

If the distance from the tip of the steel pipe to the cut site is determined, the slip stopper (10) can be placed at the corresponding position by adjusting the total length of the rope or the degree of lowering of the crane (C). However, if the length between the top of the steel pipe (P) and the cut part is not determined in advance, an indicator hole (H) is formed at the cut position of the steel pipe and an ROV (50) (Remote Operated Vehicle; unmanned underwater vehicle) is installed. The position of the slip stopper 10 can be determined by observing the hole. At this time, the indicator hole (H) may be created in advance before cutting the steel pipe (P) and used to determine the cut site, or may be formed at the cut site after cutting the steel pipe.

In this way, the purpose of the present invention, that is, the purpose of preventing the movement of the cut structure during dismantling of the marine structure, can be achieved by the slip stopper 10 disposed at the cut portion of the steel pipe. In addition, when the steel pipe (P) is a jacket, a step occurs due to cutting and disassembly of the pile (PL), and the tip of the slip stopper (10) is inserted into the pile (PL) remaining in the steel pipe, the slip stopper (10) Since the upper end hangs over the pile PL, there is no need to hang the slip stopper 10 by a rope. That is, a pile (PL) is disposed inside the steel pipe to support the lower structure on the ground, and the upper pile (PL) cut along with the steel pipe is removed in advance, forming a step at the steel pipe cut site, The slip stopper 10 may be provided with a seating portion 13 whose upper portion has a relatively larger diameter than the lower portion so that it can be seated on the step. This seating portion 13 allows the slip stopper 10 to When seated on the pile PL, the rope can be removed from the slip stopper 10 as shown in FIG. 17.

The hydraulic cutter 40 described above is used for this removal operation. That is, the first rope 21 connected to the slip stopper 10 can be cut by operating the hydraulic cutter 40 through the hydraulic hose 41 extended to the outside and wound around the hose reel 42. By cutting the first rope (21), all ropes connected to the crane (C) are separated from the slip stopper (10), and the cut ropes are lifted by the crane (C) and moved out of the steel pipe.

When the slip stopper 10 is placed at the cutting position of the steel pipe through the above-described process, the steel pipe of the leg is stably cut as the movement of the upper structure is limited when cutting the remaining legs of the structure, and the cut upper structure is carried by a crane ( It can be removed by C).

And when the upper structure is removed, the slip stopper 10 is partially exposed on the steel pipe, as shown in FIG. 18. In order to lift the slip stopper 10, the crane C is lowered, and as shown in FIG. 19, at the bottom of a pair of ropes (hereinafter referred to as the '8th rope 28') hanging from the crane C. Each of the provided shank hooks is coupled to the first shackle 31 at the top of the slip stopper 10 through the ROV 50.

When the 8th rope 28 is coupled to the 1st shackle 31, the crane C is raised to separate the slip stopper 10 from the top of the steel pipe and the slip stopper 10 is lifted.

As above, the rights of the present invention are not limited to the embodiments described above but are defined by the claims, and various modifications and modifications can be made by those skilled in the art within the scope of the rights set forth in the claims. It is self-evident that you can do this.

10: slip stopper 11, 12: slope
13: Seating part
21: first rope 22: second rope
23: Third rope
24: 4th rope 24a: 1st hook
24b: Tractor 24c: Support rope
25: 5th rope
26: 6th rope 26a: 2nd hook
27: 7th rope 28: 8th rope
31: 1st shackle 32: 2nd shackle
33: 3rd shackle 34: 4th shackle
35: 5th shackle 36: 6th shackle
37: Shank hook
40: Hydraulic cutter 41: Hydraulic hose
42: hose reel
50: ROV
P: steel pipe
PL: file
C: Crane
H: indicator hole

Claims (5)

delete In the disassembly method of separating the upper structure from the lower structure by cutting a plurality of steel pipes (P), a steel pipe support method for preventing movement of the upper structure by temporarily supporting the separated steel pipes,
A first rope 21 is connected to one end of a slip stopper 10 having a diameter that can be inserted into the steel pipe, and a second rope 22 connected to the first rope 21 is connected to a crane C or the crane. A first step of connecting a fourth rope (24), which is connected to the third rope (23) connected to (C) and has a hook at the end, to the first rope (21);
After inserting the slip stopper 10 into the steel pipe and attaching the hook of the third rope 23 to the tip of the steel pipe, the second rope 22 is dismantled from the crane C or the third rope 23. Step 2;
One end of the fifth rope 25, which has a length corresponding to the cut position of the steel pipe, is connected to the first rope 21 or the second rope 22, and the other end of the fifth rope 25 is connected to a crane ( C) or the third step of mounting on the third rope (23);
A fourth step of lifting the crane (C) and dismantling the hook of the fourth rope (24) from the tip of the steel pipe; and
A fifth step of lowering the crane (C) so that the central portion of the slip stopper (10) is placed at the cutting position of the steel pipe. A method of supporting a cut steel pipe when dismantling an offshore structure made of a large-diameter steel pipe, comprising: .
According to paragraph 2,
In the first step, a tugger for manipulating the hook is fastened to the hook, a support rope connected to the crane C is hung on the hook, and the fourth rope 24 is moved upward together with the hook. A method of supporting a steel pipe cut when dismantling an offshore structure made of a large-diameter steel pipe, further comprising the step of pulling up.
According to paragraph 2,
In the first step, a hydraulic cutter 40 capable of cutting the first rope 21 is mounted on one end of the slip stopper 10, and a hydraulic hose 41 connected to the hydraulic cutter 40 is installed. Further comprising extending and disposing the steel pipe outside,
In the fifth step, the step of operating the hydraulic cutter 40 through the hydraulic hose 41 to cut the first rope 21 connected to the slip stopper 10 disposed at the cutting position of the steel pipe is further performed. A method of supporting cut steel pipes during dismantling of marine structures made of large-diameter steel pipes, comprising:
According to paragraph 4,
Inside the steel pipe (P), a pile (PL) is placed on the ground to support the lower structure, and the upper pile (PL) cut along with the steel pipe is removed in advance, forming a step at the steel pipe cut site. ,
The slip stopper 10 is provided with a seating portion 13 having a relatively large diameter at the upper portion compared to the lower portion so that it can be seated on the step. Supporting steel pipes cut during dismantling of marine structures made of large-diameter steel pipes. method.

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