KR101710566B1 - Offshore Structure - Google Patents

Abstract

According to the present invention there is provided an offshore structure comprising an upper facility 1 for producing a fluid and a lower hull 2 for storing the fluid produced by the upper facility 1, A lower tank 100 located below the sea level; And an upper tank 200 partially exposed to the sea level, wherein the upper tank 200 includes: a first tank 210 having a cylindrical shape for storing fluid; And a plurality of protrusions 220 surrounding outer sides of the first tanks 210 and protruding from the first tanks 210 at predetermined intervals toward the outside of the first tanks 210. The outer walls 221 of the protrusions 220 Is formed in an arc shape.

Description

Offshore Structure with Tangerine Cross Section {Offshore Structure}

More particularly, the present invention relates to a floating production storage and offloading (FPSO) system, a concrete GBS, To an offshore structure having a Tangerine section that takes an efficient cross-sectional structure applicable to a section of floating SPAR and semi-submersible.

In recent years, as industrialization and industrialization have accelerated, the use of natural resources (petroleum, natural gas, etc.) is gradually increasing, and stable production and supply of natural resources with limited reserves are becoming very important.

Since the offshore plant operates from 3 to 30 years after installation at the oil field or gas exploration site, the design considerations are also quite severe, and the climate effects such as wind and waves and the special environmental conditions of the sea, as well as oil There is a need for a variety of high-tech technologies related to the safety of fire and explosion due to the production of products.

In addition, due to the recent increase in demand for petroleum resources development in the deep sea of more than 1,000 meters, the securing and development of technology is progressing variously. Especially, it is possible to simultaneously drill, It is a trend to develop an offshore plant for the purpose. As a result, demand and prices of offshore plants are rising along with global demand for energy and resources, and soaring prices, and it is expected that the current trend will continue even after five years.

In particular, orders for offshore drilling facilities are expected to continue steadily over the next several years, from gravity based structures and fixed platform structures to floating structures and semi-submersible structures. Orders are increasing rapidly.

Among them, FPSO (Floating Production Storage and Offloading), which is a marine plant designed to carry out the loading and unloading functions for floating oil production, storage, and landfill facilities, is a facility that enables operation even in the deep sea. FPSO drying is increasing in line with the development of deep-sea resources because it is more flexible and more usable than structures.

FPSO is currently being used to produce crude oil or natural gas from oil fields. For example, LNG FPSO has been actively developed in recent years due to depletion of oil fields and increased demand for clean fuels. Oil FPSO and LNG FPSO can be said to be a floating marine refinery that can refine, store and transport crude oil or natural gas while floating in the sea.

Floating fluid production and storage facilities for storing crude oil and so on are floated on the ocean, so they are more affected by sea waves than fixed facilities.

Therefore, in order to secure the stability of the facility, it is required to have a structure that is less influenced by sea waves.

The following techniques have been disclosed as prior art for enhancing the stability of such a floating fluid production storage facility.

- Patent No. 10-2010-0020829

- Patent No. 10-1205357

However, in the case of the conventional technologies, a separate structure for reducing vibrations due to sea waves is added to the floating fluid production and storage facility, and the structure of the sea wave reduction of the equipment itself has not been proposed.

In addition, it is necessary to study the structure that can reduce the pressure provided by sea waves because all sea structures as well as floating sea structures can not escape the effects of the sea waves at all times.

The object of the present invention is to provide a marine structure having a tenth girder section capable of increasing the stability of a structure by effectively dispersing the influence of sea waves .

According to an aspect of the present invention, there is provided an offshore structure comprising an upper facility 1 for the production of marine drilling fluids and a lower hull 2 for storing the fluid produced by the upper facility 1, The hull (2) comprises a lower tank (100) located below the sea surface; And an upper tank 200 partially exposed to the sea level, wherein the upper tank 200 includes: a first tank 210 having a cylindrical shape for storing fluid; And a plurality of protrusions 220 surrounding outer sides of the first tanks 210 and protruding from the first tanks 210 at predetermined intervals toward the outside of the first tanks 210. The outer walls 221 of the protrusions 220 Is formed in an arc shape.

Here, the lower tank 100 includes a cylindrical second tank 110 for storing a fluid, and the diameter of the second tank 110 is longer than the diameter of the upper tank 200 It may be an offshore structure.

Also, the outer wall 221 may be a marine structure in which a tensile force is introduced by a tension member 222.

The center pillar 230 and the protrusion 220 may further include a center pillar 230 formed at a central portion of the first tank 210, 1 through the inner partition wall 240 and the shape of the cross section formed by the protrusion 220 and the first inner partition wall 240 is a 1/9 arc shape.

In addition, the present invention may further include a protrusion reinforcing member 250 connecting the outer wall 221 and the first tank 210.

The fixing cable 300 further includes a fixing cable 300 connecting the lower hull 2 and the bottom surface to limit the flow of the offshore structure, Which may be an offshore structure.

The both ends of the tension member 222 are connected to the protrusions 220 adjacent to both sides of the outer wall 221 into which the tension force by the tension member 222 is introduced.

The center pillar 230 extends downward to the center of the second tank 110 and the outer surface of the center pillar 230 and the second tank 110 are connected to the inside of the second tank 110, And a second inner partition wall 120 partitioning the space.

According to the present invention, it is possible to effectively disperse the pressure of the sea waves applied to an offshore structure, thereby enhancing the stability of the structure.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a view showing an upper structure and a lower hull of an offshore structure having a tenth girder section according to an embodiment of the present invention. Fig.
2 is a view illustrating a lower hull of an offshore structure having a tenth girder section according to an embodiment of the present invention.
3 is a cross-sectional view of an upper tank of an offshore structure having a tenter section in accordance with an embodiment of the present invention.
4 is a cross-sectional view of a lower tank of an offshore structure having a tenter section in accordance with one embodiment of the present invention.
5 is a view showing a configuration of a tension member formed on an outer wall of a protrusion of an offshore structure having a tenth girder section according to an embodiment of the present invention;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, A duplicate description will be omitted.

It is also to be understood that the terms first, second, etc. used hereinafter are merely reference numerals for distinguishing between identical or corresponding components, and the same or corresponding components are defined by terms such as first, second, no.

In addition, the term " coupled " is used not only in the case of direct physical contact between the respective constituent elements in the contact relation between the constituent elements, but also means that other constituent elements are interposed between the constituent elements, Use them as a concept to cover each contact.

The present invention relates to an offshore structure having a tenter section including an upper facility 1 for producing a fluid such as crude oil and a lower hull 2 for storing the fluid produced by the upper facility 1 ).

The tenter girder cross-sectional shape of an offshore structure according to the present invention can be efficiently applied not only to cylindrical FPSO but also to concrete GBS, floating spar and semi-submersible section which are oil & gas production and storage facilities.

The tangential section refers to a section formed on the outer circumferential surface of a projecting portion of a curved surface, which is seen from the cross section of the orange.

Hereinafter, an embodiment of the present invention will be described using a floating storage facility FPSO.

 The lower hull 2 of an offshore structure according to an embodiment of the present invention includes a lower tank 100 positioned below the sea surface and an upper tank 200 partially exposed to the upper surface of the sea surface ).

Since the upper tank 200 is positioned so as to span the boundary of the sea surface, it corresponds to a configuration that directly receives the influence of sea waves.

Accordingly, the present invention is characterized in that the lower tank 2 is divided into an upper tank 200 directly receiving the influence of sea wave and a lower tank 100 receiving less influence of the sea water.

The upper tank 200 includes a cylindrical first tank 210 for storing a fluid and a plurality of protrusions 240 protruding from the first tank 210 at predetermined intervals toward the outside of the first tank 210 220, and the outer wall 221 of the protrusion 220 may have a tapered cross-section.

That is, as shown in the sectional view of FIG. 3, the plurality of protrusions 220 take a shape to surround the cylindrical first tank 210.

Each protrusion 220 is formed in the shape of an arc, and the size of each arc is preferably kept constant.

When formed in this shape, it is possible to effectively disperse the pressure due to the sea wave applied to the outer wall 221 as compared with the cylindrical sea structure.

In order to obtain the optimum cross-sectional shape according to the present invention, considering the material advantage of the concrete excellent in compressive force, a curved surface of the outer wall of the tapered shape And a parametric study was performed to find the optimal curvature.

Figure 1 schematically illustrates dr and rf which determine the shape of the tgerine, and dr is defined to obtain the rf for the outer diameter at regular intervals. [Table 1] refers to nine types of objects, which are defined by an existing circular section and dr at 0.5 m intervals from 0.5 m to 4 m.

[Figure 1]

Circle (d _r = 0.0 m) Type 1 (d _r = 0.5 m) Type 2 (d _r = 1.0 m)

( r_f = 42.6 m )

(r _f = 42.6 m)

(r _f = 31.1 m)

(r _f = 24.3 m) Type 3 (d _r = 1.5 m) Type 4 (d _r = 2.0 m) Type 5 (d _r = 2.5 m)

(r _f = 20.8 m)

(r _f = 18.2 m)

(r _f = 16.4 m) Type 6 (d _r = 3.0 m) Type 7 (d _r = 3.5 m) Type 8 (d _r = 4.0 m)

(r _f = 15.1 m)

(r _f = 14.2 m)

(r _f = 13.6 m)

The following [Table 2] to [Table 7] show the stresses for each type.

Outer wall outside
side

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side

Inner wall outside
side

of mine
side

Center pole outside
side

of mine
side

Outer wall outside
side

of mine
side

Inner wall outside
side

of mine
side

Center pole outside
side

of mine
side

TYPE3 was selected as the most effective section when the slope of the stress was the smallest and the maximum and minimum stresses were the most similar to each other on the basis of the tables [Table 2] to [Table 7].

[Table 8] to [Table 10] are graphs showing the stress of the TYPE 3 and the circular cross section.

As shown in Table 8, it can be seen that the stress of TYPE3 is smaller than that of the existing circular section, and the maximum and minimum values of stress are similar in all sections. Particularly, the most advantage is that there is no section where tensile stress occurs at all outer walls. In addition, the maximum compressive force is also about half.

Outer wall outside
side

of mine
side

[Table 9] shows that the inner wall is similar to the outer wall. The sidewall also has no section where tensile is generated and the maximum compressive force is also about half that of the circular section.

Inner wall outside
side

of mine
side

As shown in Table 10, the compressive stress in the outer side of the center column of TYPE3 is larger than that of the circular column, and both compressive and tensile stresses occur in the inner side. However, the results of this analysis do not consider the horizontal bulkhead of the center column. Therefore, compressive and tensile forces are expected to be lower than those of the below analysis in the three - dimensional analysis. The tensile stress is considered to be solved by placing the tendon.

Center pole outside
side

of mine
side

[Table 11] shows that the stress of TYPE3 is about 4 times larger than that of the circular cross section due to the stress generated in the bulkhead, but this is all compressive stress and maximum value is not a problem considering the compressive strength of concrete.

The cross-sectional shape of the center pillar 230 of the offshore structure according to an embodiment of the present invention is preferably formed in an arcuate shape.

When the center pillar 230 is formed into an arch shape, the shear force and the bending moment are remarkably reduced, and the compressive force is increased instead, so that the region where the tension is generated disappears and becomes a full-length compression member. Since the main material is designed as a concrete that is strong in compression, it can be seen as a very efficient structure.

Table 11 below is a graph in which the cross-sectional shape of the center pillar 230 in the case of housing 1 million barrels of fluid is an arch shape (a million barrel tangerine graph) or a circle (a million barrel flower graph) .

Center wall shaft
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In addition, when the outer wall 221 is made of concrete, it is effective that a tension force by the tension member 222 is introduced into the outer wall 221 to increase the resistance against the working load (FIG. 5).

In other words, tensile stress is not generated in the outer wall 221 due to hydrostatic pressure, but tensile force is introduced to compensate for the generation of tensile force due to asymmetric load.

Both ends of the tension member 222 are connected to both sides of the outer wall 221 to which the tension force is applied by the tension member 222 in order to increase the coupling force of the plurality of the protrusions 220 and improve the structural stability. ) (Figure 5).

The marine structure according to an embodiment of the present invention further includes a center pillar 230 formed at a center portion of the first tank 210. The center pillar 230 and the protrusion 220 are disposed in the inside of the first tank 210 (FIG. 3) through a first inner partition wall 240 partitioning the space.

Accordingly, the cross-sectional shape formed by the protruding portion 220 and the first inner partition wall 240 is formed into an arc shape, and the arc size is preferably 1/9 arc.

That is, the upper tank 200 can be grasped as a circular shape having nine projections 220 formed on its outer side by combining nine arc shapes (FIG. 3).

The center pillar 230 is formed to extend downward to a central portion of a second storage tank 110 to be described later and functions as a central axis of the lower hull 2.

In this configuration, the load provided to the protruding portion 220 by the wave can be transmitted to the first inner partition wall 240.

That is, the curvature of the protrusion 220 connected to the first inner partition wall 240 is reduced in order to take advantage of the material advantages of the concrete having the excellent compressive force for forming the protrusion 220, So that the load provided to the load unit 220 can be effectively dispersed.

The marine structure according to an embodiment of the present invention includes an outer wall 221 of the protrusion 220 and a cylindrical first tank 210 in order to improve the structural stability of the protrusion 220 and the coupling force between the protrusion 220 and the first tank 210 And may further include a protruding portion reinforcing member 250 (FIG. 3).

The lower tank 100 preferably includes a cylindrical second tank 110 for storing the fluid and a diameter of the second tank 110 is preferably longer than a diameter of the upper tank 200 (FIGS. 1 and 2) .

That is, by forming the storage space in which the fluid or the like is stored in the lower tank 100 to be wider, the center of gravity of the offshore structure can be lowered, thereby enhancing the stability when the equipment is floated.

The outer surfaces of the central pillar 230 and the second tank 110 may be connected through a second inner partition 120 defining the inner space of the second tank 110 (FIG. 4).

The marine structure according to an embodiment of the present invention may further include a fixing cable 300 connecting the bottom hull 2 and the bottom surface to limit the flow of the offshore structure, And is preferably coupled to the outer wall of the tank 210 (FIG. 4).

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 or scope of the invention as defined in the appended claims. It is to be understood that both the technical idea and the technical spirit of the invention are included in the scope of the present invention.

1: Upper equipment
2: Lower hull
100: Lower tank
200: upper tank
300: Fixed cable

Claims (8)

1. An offshore structure comprising an upper equipment (1) for the production of marine drilling fluids and a lower hull (2) for storing the fluids produced by said upper equipment (1)
The lower hull (2)
A lower tank 100 located below the sea level; And
And an upper tank (200) partly exposed above sea level,
The upper tank (200)
A first tank 210 of a cylindrical shape for storing fluid; And
And a plurality of protrusions 220 surrounding the first tank 210 and protruding from the first tank 210 at predetermined intervals toward the outside of the first tank 210,
The outer wall 221 of the protrusion 220 is formed in an arcuate shape,
Wherein a tension force is introduced into the outer wall (221) by a tension member (222).
The method according to claim 1,
The lower tank (100)
And a second tank (110) of cylindrical shape for storing fluid,
Wherein a diameter of the second tank (110) is longer than a diameter of the upper tank (200). delete 3. The method according to claim 1 or 2,
And a center pillar 230 formed at the center of the first tank 210,
The center column 230 and the protrusion 220 are connected to each other through a first inner partition wall 240 partitioning the inner space of the first tank 210,
Wherein a shape of the cross section formed by the protrusion (220) and the first inner partition wall (240) is 1/9.
3. The method according to claim 1 or 2,
Further comprising a protrusion reinforcing member (250) connecting the outer wall (221) to the first tank (210).
3. The method according to claim 1 or 2,
Further comprising a fixed cable (300) coupling the undersurface to the lower hull (2) to limit the flow of the offshore structure,
Wherein the fixed cable (300) is coupled to the first tank (210).
The method according to claim 1,
Wherein both ends of the strap (222) are coupled to the protrusions (220) adjacent to both sides of the outer wall (221) to which a tension force is applied by the strap (222).
5. The method of claim 4,
The center pillar 230 extends downward to the central portion of the second tank 110 and the outer surface of the center pillar 230 and the second tank 110 is connected to the inner space of the second tank 110 And a second inner partition wall (120) partitioning the first inner partition wall (120).

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