TW202300404A - Semi-submersible rig wherein the deep-draft central column is connected to the peripheral columns that are shallower in draft by the support arm disposed above the peripheral column and the float disposed below the peripheral column to form an integral structure - Google Patents

Abstract

The invention provides a semi-submersible rig which can be applied to offshore operations and is characterized by comprising a deep-draft central column, a plurality of peripheral columns that are shallower in draft than the central column, a support arm, a float and a position-keeping system; wherein the plurality of peripheral columns are equally spaced around the deep-draft central column, and the deep-draft central column is connected to the peripheral columns that are shallower in draft by the support arm disposed above the peripheral column and the float disposed below the peripheral column to form an integral structure. The semi-submersible rig allows for safer and more effective offshore operations.

Description

Semi-submersible platform

The present invention relates to a semi-submersible platform for offshore operations, especially a semi-submersible platform with a deep-draft central column, the top of which can be used as the foundation for large-scale wind power generators or heavy lifting facilities for offshore operations. seat.

The semi-submersible platform is an offshore structure that provides offshore operations such as wind power generation, walrus observation, drilling and scientific research. The semi-submersible platform can be used in deeper waters, overcoming the limitation of fixed offshore platforms in shallower water depths , Poor anti-typhoon ability and difficult to set up problems.

In recent years, under the influence of increasing global demand for energy and rising awareness of environmental protection, the development of green energy has become a current trend. Among them, offshore wind power that can be built in sea areas and has a large power generation scale has attracted more attention from various countries. Offshore wind power can not only The use of more stable offshore wind power to generate electricity can also reduce the impact on the living environment on land (for example: loud noise, occupying a large area of land and destroying the ecological landscape). Due to the increasingly saturated development of offshore wind farms in shallow waters and consideration of the maintenance of offshore fishing grounds , Offshore wind power development locations are gradually entering deep waters. Although deep waters have better wind field conditions with strong and stable winds, they have to face higher marine construction costs and technical thresholds.

On the other hand, the world is still highly dependent on traditional energy sources (such as coal, oil and natural gas). Competition is fierce. With the development of offshore oil exploration technology, it is discovered that the vast ocean has rich oil reserves. Countries have invested in the exploration and exploitation of seabed oil. Offshore drilling platforms have also emerged as the times require. However, their technical means are more advanced than land It is more complex, and the construction investment is higher than that on land. In order to overcome the difficulties of offshore operations, drilling platforms suitable for various sea areas have also been developed one after another.

At present, platforms used for offshore operations are divided into fixed and floating platforms. Fixed platforms include jacket platforms or concrete gravity platforms, etc. Floating platforms include column buoys, tension leg platforms, or semi-submersible platforms. As mentioned above, both wind power generation and drilling are gradually shifting from land to water. The platform changes widely with the depth of the water, and it also changes from a fixed platform with foundation piles fixed on the seabed to a floating platform. Among them, the semi-submersible platform Because of its advantages of good stability, strong wind and wave resistance, wide application depth, low transportation cost and reusability, it has extremely high economic value in application.

However, semi-submersible platforms used in relatively deep waters have to face quite severe environmental challenges, and must also withstand the impact of wind, tsunamis and earthquakes. Traditional semi-submersible platforms will still have large movements due to external forces in deep waters Changes (rolling, pitching, heaving, etc.) aggravate the vibration of the platform and affect the efficiency and safety of the overall offshore operation. In the long run, the service life of the platform will be shortened and the operating cost will be increased.

Patent Document 1 discloses a floating wind turbine platform structure with optimized transfer of wave and wind loads, the platform consists of three columns (composed of two concentric cylinders, the outer concentric cylinder is used as a float for the outer shell to provide buoyancy ) and pipe truss components connected to the columns. The wind turbine is installed on one of the columns and has an active ballast system, which can offset the moment caused by the wind by actively adjusting the ballast water in the column to keep the platform level , using a mooring positioning system, a water interceptor plate is provided at the bottom of each column to provide tuning of the platform resonance period relative to the wave period. However, the structure of the platform is complex, resulting in heavy overall weight, difficult manufacturing and high cost, and the undulating motion caused by external force is also relatively violent.

Moreover, while thinking about reducing manufacturing costs, it is also urgent to design a semi-submersible platform with general structural principles that can be applied not only to deep waters but also to shallow waters; It is also expected that the semi-submersible platform can also carry large-volume and heavy-weight units while reducing the complexity of structural design, increasing the depth of application, and reducing manufacturing costs. Accordingly, it is very important to develop a semi-submersible platform that is strong in resistance to external forces, wide in water depth, high in stability and capable of carrying large units. [Prior Technical Literature] [Patent Document]

[Patent Document 1] TW I722370

[Technical problem to be solved by the invention]

In view of this, the main purpose of the present invention is to provide a semi-submersible platform, which is to provide a semi-submersible platform with strong resistance to external forces, better stability, wide range of applicable water depth, simple structure and capable of carrying large-scale units to solve existing problems. The invention of the problem. [Technical means]

Accordingly, the present invention provides a semi-submersible platform, which includes: a deep-draft central column, a plurality of peripheral columns with drafts shallower than the central column, bracing arms, buoys, a base on the central column, and a position maintaining system ; wherein, the plurality of peripheral columns are equidistantly distributed on the periphery of the central column, and the central column and the peripheral column are integrated by the support arm located above the peripheral column and the buoy positioned below the peripheral column Structural connections.

In some implementation forms, the bottom of the deep-draft center column is loaded with fixed ballast to lower the overall center of gravity and reduce its rolling/pitching motion.

In some implementation forms, the deep-draft center column can be a whole.

In some implementation forms, the central column can be an integral body formed by a plurality of parts connected by one or more frame structures, so as to further reduce the overall center of gravity of the semi-submersible platform.

In some implementation forms, the bottom of the peripheral column and the pontoon are loaded with fixed and/or variable ballasts to further lower the overall center of gravity of the semi-submersible platform.

In some embodiments, the peripheral columns and the buoy provide space and access to transfer the variable ballast from one side of the semi-submersible platform to the other.

In some embodiments, the bottom of the peripheral column provides structural support for the position maintaining system.

In some implementation forms, the position keeping system is applied to the mooring system of floating offshore wind power generation or the dynamic positioning system of heavy lifting facilities.

In some implementation forms, the present invention provides an offshore operation facility, which is installed on the foundation of the semi-submersible platform of any one of the above-mentioned implementation forms.

In some implementation forms, the offshore operation facility can be applied in both shallow water area and deep water area. [Effect of the invention]

With the semi-submersible platform of the present invention, the deep draft of the center column can lower the overall center of gravity to resist heaving, pitching and rolling motions caused by wind or waves, and can provide sufficient buoyancy to maintain the overall good The stability and resistance to external forces are also capable of loading large-scale units.

The fixed ballast installed at the bottom of the deep draft center column can also lower the overall center of gravity of the semi-submersible platform, increase its restoring moment to achieve static and dynamic stability, and further reduce its roll/roll by increasing its moment of inertia Pitching motion.

Outer columns with a shallower draft than the central column can provide additional surface area moment of inertia to increase the restoring moment of the semi-submersible platform, and the peripheral columns and buoys also provide additional mass to increase the moment of inertia, while providing increased mass and viscosity for hydrodynamic forces Damping force and moment to further enhance its stability and reduce the movement of the semi-submersible platform in all directions. In addition, it also enables the overall natural frequency of the platform to stay away from the peak period of wave energy to avoid overall instability caused by resonance and reduce exercise.

In addition, semi-submersible platforms traditionally used in deep waters often need to increase the overall size and configure expensive position maintenance systems to overcome the harsh sea state changes at sea, seek overall stability and reduce movement, resulting in higher overall costs and maintenance. Not easy, the central column of the present invention can also be a whole formed by a plurality of parts connected by one or a plurality of frame structures, thereby further reducing the overall center of gravity and increasing damping so that it can be well applied to deeper waters, and because of its The structure is simple, the construction cost can also be reduced, and it has economic utilization value.

The semi-submersible platform of the present invention and an exemplary implementation form of the semi-submersible platform of the present invention will be described below with reference to the drawings. It should be understood that the following content does not limit the implementation of the present invention in the following manner or form, but is for explaining the detailed content and implementation effect of the present invention.

1 to 4 show a semi-submersible platform according to the first exemplary embodiment of the present invention. As shown in FIGS. The outer column 12 shallower than the central column, a plurality of bracing arms 13, the buoy 14 located below the outer column 12 and the position keeping system 15, wherein, in this embodiment, the position keeping system is set as a mooring system.

The four peripheral columns 12 with a draft shallower than the central column are arranged to be equidistantly distributed on the periphery of the deep-draft central column 11, and the deep-draft central column 11 and the peripheral column 12 with a draft shallower than the central column are connected by the support arm 13 and the buoy 14 Make overall structural connections. Further, when the semi-submersible platform 1 of the first embodiment of the present invention is applied to offshore operations, the central column 11 and the peripheral column 12 can be set as components perpendicular to the sea surface, and the buoys 14 at the lower end of the peripheral column 12 and the upper end The support arm 13 can be perpendicular to the central column 11 and the peripheral column 12, the support arm 13 and the buoy 14 are connected as a member between the peripheral column 12 and as a member connecting the peripheral column 12 and the central column 11, and are integrally connected. The mooring system connected to the semi-submersible platform 1 fixes the platform on the seabed to maintain the stability of the semi-submersible platform 1 .

In addition, when the semi-submersible platform 1 of the first embodiment of the present invention is applied to offshore operations and connected to install a facility, the facility is arranged on the base 16 at the top of the central column 11, and in order to ensure the stability of the overall structure Set a certain space at the bottom of the central column 11, the peripheral column 12 and the buoy 14, and set fixed ballast at the bottom of the central column 11, and set fixed and/or variable ballast at the bottom of the peripheral column 12 and the buoy 14 . Wherein, the facility may be commonly used equipment for offshore operations, such as a large-volume wind power generation system or a high-weight offshore lifting operation facility, etc., and the present invention is not limited thereto.

In this first exemplary embodiment, due to the design shape and installation position of the central column 11 relative to the peripheral columns 12, as well as the fixed ballast loaded therein, the central column 11 has the characteristics of a deep draft, and its draft The ideal is equal to or less than half the water depth, which can provide stability, increase the moment of inertia, and support large-volume or high-weight offshore installations. And, in response to the water depth of the actual application, the length of the central column 11 can be further adjusted, and on the premise that the length of the central column 11 is greater than the peripheral column 12, the distance and diameter of the central column 11 and the peripheral column 12 can be adjusted. The length of the buoy 14.

Accordingly, the main technical features of the present invention at least include the setting of the central column 11 and the peripheral column 12, and achieve the effect of stable support by the draft difference between the central column 11 and the peripheral force column 12; The overall size of the semi-submersible platform 1 and the single size of the central column 11, peripheral column 12, support arm 13, buoy 14 and other components are designed according to its functional requirements, water depth and world-recognized industrial standards, which should be adjusted according to the application water area Change, as long as the overall size of the semi-submersible platform 1 and the relative size ratio of each component can achieve the effect of stable support, the present invention is not limited thereto.

In this first exemplary embodiment, because the center column 11 has the characteristics of deep draft, it can provide enough buoyancy to balance the weight of the wind turbine or lifting facility on its top, and make the semi-submersible platform 1 as a whole Minimizing the distribution of weight and net buoyancy also reduces shear and bending moments at critical structural discontinuities, thereby reducing the size of the overall structure as it adjusts to overall loads.

Moreover, because the peripheral column 12 with a shallower draft than the central column is connected to the buoy 14 to form an integral structure, the structural reliability of the structural elements at all critical structural discontinuities can be improved.

Moreover, the peripheral column 12 can provide an additional surface area moment of inertia to increase the restoring moment of the semi-submersible platform to further enhance its stability, and also provide additional mass to increase the moment of inertia to further reduce the overall roll/pitch motion.

Moreover, the peripheral columns 12 and the buoys 14 can also provide additional hydrodynamic mass and viscous damping force and moment, further reducing the movement of the semi-submersible platform 1 in all directions due to external forces on the sea, especially close to it. Movement within the frequency range of the natural frequency.

Moreover, because the bottom of the peripheral column 12 and the buoy 14 are loaded with fixed and/or variable ballast, the overall center of gravity of the semi-submersible platform 1 can be further reduced and its rolling/pitching movement can be reduced, and space and passages can be provided, which will be variable The ballast is transferred from one side of the semi-submersible platform 1 to the other side, and the active anti-rolling/pitching motion system enables the semi-submersible platform 1 to remain stable even in strong winds and strong currents. Maintain a near upright position and avoid tilting of the overall platform for efficient offshore operations.

Moreover, the bottom of the peripheral column 12 can provide structural support for the position keeping system 15, for example, it can support a mooring system applied to floating offshore wind power generation, or a dynamic positioning system applied to heavy lifting facilities.

Figures 5 to 6 show a semi-submersible platform 2 according to the second exemplary embodiment of the present invention. As shown in Figures 5 to 6, the semi-submersible platform 2 includes a central column with a deep draft and a plurality of vertical columns with a lower draft. Shallow peripheral columns 22 , a plurality of bracing arms 23 , buoys 24 located below the peripheral columns 22 and a position maintaining system 25 . In this second exemplary embodiment, the deep draft center column includes a first center column 211, a second center column 212 and a frame structure 26, and the frame structure 26 is used to connect the first center column 211 and the second center column 212 The central column is formed as a whole, so that the center of gravity of the semi-submersible platform 2 can be further lowered to apply to deeper waters without excessively increasing the size of the central column.

Specifically, by including the deep-draft center column of the first center column 211, the second center column 212 and the frame structure 26, the overall draft of the semi-submersible platform 2 can be increased to more than 40 meters, while the undulation and lateral The natural period of shaking is greater than the above-mentioned optimized natural period, and the semi-submersible platform 2 can also be farther away from the peak period of wave energy, so it can be expected to have better heave and roll/pitch motion performance.

In addition, with the semi-submersible platform 2 of the second exemplary implementation form of the present invention, the complexity of equipment assembly can also be reduced and the application flexibility of the semi-submersible platform can be improved; and those with ordinary knowledge in the technical field of the present invention should understand , the central column of the present invention can be further divided into more plural parts, so as to further enhance the application flexibility.

In this second exemplary implementation form, a plurality of peripheral columns 22 whose draft is shallower than the central column are equidistantly distributed on the periphery of the deep-draft central column, and the deep-draft central column and the peripheral column are connected by braces 23 and buoys 24 The column 22 is connected structurally as a whole. In addition, when the semi-submersible platform 2 of the second embodiment of the present invention is applied to offshore operations and a facility is connected and installed, the facility is arranged on the base 27 at the top of the central column.

In order to reduce the overall length/width of the semi-submersible platform 2 and reduce the diameter of the peripheral column 22 to be smaller than the diameter of the central column, while maintaining the same or better heave and pitch/roll motion performance, it can also be considered by In addition to connecting the first central column 211 and the second central column 212 with the frame structure 26 , more fixed ballasts are used at the bottom of the central column.

Those with ordinary knowledge in the technical field of the present invention should be able to understand that the size of the deep-draft center column of the present invention can be adjusted in response to different application waters, so as to reduce the overall draft and be applied to shallower waters; accordingly, the present invention The size and quantity of the central column, peripheral columns, support arms and buoys can be adjusted according to the design specifications, including the restrictions on the working water depth and the movement of the semi-submersible platform, which is not limited by the present invention.

Hereinafter, the semi-submersible platform of the present invention will be described with examples.

A floating offshore wind turbine with a power of about 15MW including a structural tower is set up to operate in waters with a water depth of 50-100 meters. The total weight of the wind turbine is about 3,000 tons, and the height from the sea surface is about 160 meters. Install the wind turbine on the base of the semi-submersible platform. When the semi-submersible platform uses four peripheral columns, the overall width/length of the semi-submersible platform is 70-80 meters, and the height from the sea surface is about 10 meters feet, and depending on the depth of the water where it is installed, its draft or the length of its central column 11 below the sea surface is 25 to 50 meters; specifically, the overall draft of the semi-submersible platform is equal to or less than half of the water depth.

In one embodiment, the central column of the semi-submersible platform is provided with fixed ballast, and the peripheral column and buoys are provided with variable ballast, and the ballast is distributed in all positions where the net difference between weight and buoyancy is close to 0. Thereby its structural size and weight can be reduced to the allowable minimum.

In another embodiment, the central column of the semi-submersible platform is provided with fixed ballast, and the fixed ballast is provided between the peripheral column and the buoy, and the ballast is distributed in all positions where the net difference between weight and buoyancy is close to 0. Thereby its structural size and weight can be reduced to the allowable minimum.

Accordingly, further set the size of each component of the semi-submersible platform. In response to the overall size of the semi-submersible platform and the need to support wind turbines, the diameter (D _c ) of the central column of the semi-submersible platform is set to 12-16 meters, and the length (L _c ) is set to 35-60 meters; The diameter of the column (D _s ) is set to 8~16 meters, the length (L _s ) is set to 15~20 meters; the diameter of the support arm (D _b ) is set to 6~7 meters; the width of the buoy (W _p ) is set to 6~8 meters, and the thickness (D _p ) is set to 3~4 meters.

Under this setting, the optimized diameters of the central column and the peripheral column are both 12 meters, and the draft of the optimized central column is as deep as possible. Away from peak periods of wave energy, so heave is small and pitch/roll motions are expected to be small.

In addition, if the peripheral column is set to have a larger diameter (greater than 12 meters), its length can be shorter (less than 20 meters), so as to reduce the natural frequency of the overall undulation and have better undulation performance.

In addition, if more fixed ballasts are installed at the lower end of the central column, the diameter of the peripheral column can be reduced (less than 12 meters), and the overall width/length of the semi-submersible platform can also be reduced (less than 70 meters). And still maintain the same or better overall heave and pitch/roll natural frequency and motion performance in all directions.

The above examples are used to illustrate the implementation of the present invention, but the present invention is not limited thereto. As long as it does not depart from the scope of the patent application for the present invention, those that have the technical characteristics of the present invention and have modifications are also included in the scope of protection of this patent.

1:Semi-submersible platform 11: Center column 12: Outer column 13: Support arm 14: buoy 15: Position keeping system 16: base 2:Semi-submersible platform 211: The first central column 212: Second center column 22: Outer column 23: brace arm 24: buoy 25: Position keeping system 26:Frame structure 27: Base

[FIG. 1] is a perspective view showing an exemplary embodiment of the present invention. [FIG. 2] is a bottom view showing an exemplary embodiment of the present invention. [FIG. 3] is a side view showing an exemplary embodiment of the present invention. [FIG. 4] is a plan view showing an exemplary embodiment of the present invention. [FIG. 5] is a perspective view showing another exemplary embodiment of the present invention. [FIG. 6] is a side view showing another exemplary embodiment of the present invention.

1:Semi-submersible platform

11: Center column

12: Outer column

13: Support arm

14: buoy

15: Position keeping system

16: base

Claims (10)

A semi-submersible platform, which can be applied to offshore operations, is characterized in that it comprises: A deep draft center column; A plurality of peripheral columns whose draft is shallower than that of the central column; brace; float; base; and position keeping system; Wherein, the pedestal is set on the central column, and the plurality of peripheral columns whose draft is shallower than the central column are equidistantly distributed on the periphery of the central column. The pontoon at the lower part of the column structurally connects the central column with the peripheral column. The semi-submersible platform according to claim 1, wherein the bottom of the central column is loaded with fixed ballast to lower the overall center of gravity and reduce its rolling/pitching motion. The semi-submersible platform as described in claim 1, wherein the central column can be a whole. The semi-submersible platform as described in Claim 1, wherein the central column can be formed as a whole by a plurality of parts connected by one or more frame structures, so as to further reduce the overall center of gravity of the semi-submersible platform. The semi-submersible platform as described in any one of claims 1 to 4, wherein the bottom of the peripheral column and the buoy are loaded with fixed and/or variable ballasts to further lower the overall center of gravity of the semi-submersible platform. The semi-submersible platform as claimed in claim 5, wherein the peripheral column and the buoy provide space and passage for transferring the variable ballast from one side of the semi-submersible platform to the other side. The semi-submersible platform according to any one of claims 1 to 4, wherein the bottom of the peripheral column provides structural support for the position keeping system. The semi-submersible platform according to any one of claims 1 to 4, wherein the position keeping system is applied to a mooring system for floating offshore wind power generation or a dynamic positioning system for heavy lifting facilities. An offshore operation facility is characterized in that it is installed on the base of the semi-submersible platform described in any one of claims 1 to 8. As for the offshore operation facility mentioned in Claim 9, the offshore operation facility can be used in shallow water areas and deep water areas.

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