Tension-Leg Platform Anchoring System
A tension-leg platform anchoring system is used to tether the columns of a floating platform to the seabed and restrict movement of the entire platform. The tension-leg platform anchoring system includes a topside and a plurality of anchored floating supports. The topside provides a deck for supporting workers and equipment. The anchored floating supports are used to keep the topside afloat and limit movement. The anchored floating support includes a column, at least one mooring assembly, and an anchor. The column is connected to the topside and is used to keep the tension-leg platform afloat. The mooring assembly includes a column coupler, a first tendon, and an anchor coupler, which are used together to tether the column to the anchor. The column coupler is tethered to the anchor coupler through the first tendon, which is connected to the column by the column coupler.
The current application is a continuation-in-part (CIP) application of a U.S. non-provisional application Ser. No. 14/853,898 filed on Sep. 14, 2015. The U.S. non-provisional application 14/853,898 claims a priority to a U.S. provisional application Ser. No. 62/049,410 filed on Sep. 12, 2014. The U.S. non-provisional application 14/853,898 was filed on Sep. 14, 2015, while Sep. 12, 2015 was on a weekend.
The current application is further a continuation-in-part (CIP) application of U.S. non-provisional application Ser. No. 14/708,165 filed May 8, 2015 which claims priority to U.S. Provisional Patent application Ser. No. 61/990,471 filed on May 8, 2014 and U.S. Provisional Patent application Ser. No. 62/049,410 filed on Sep. 12, 2014.
FIELD OF THE INVENTIONThe present invention relates generally to floating offshore structures. More specifically, the present invention is a buoyant semi-submersible offshore platform which uses tendons made from cables or chains instead of steel pipes to moor the structure to the seabed, thus restricting the movement of the present invention on the water.
BACKGROUND OF THE INVENTIONOffshore platforms, used for oil and natural gas production and a number of other utilities are often susceptible to wind, wave, and current forces. As a result, such platforms must overcome such forces in order to maintain a relatively fixed position. It is important that the floating structure remain stable throughout its operation so that it is safe for people to work on the structure and so that the structure can function properly. Traditional catenary moorings typically consist of freely hanging lines that connect a floating structure to anchors, or piles, on the seabed, positioned at some distance from the floating structure. Steel-linked chain and wire rope have conventionally been used. These lines form a catenary shape and rely on an increase or decrease in line tension as the lines lift off or settle on the seafloor. This is needed to produce a restoring force as the surface platform is displaced by the environment. Because the restoring force provided by the traditional mooring system is generally small, the floating platform experiences all six degree of freedom motions.
Another type of mooring system uses tendons and is typically used in Tension-Leg Platforms (TLP). The mooring system is made up of a set of tension legs, or tendons, which attach to the platform and connect to a template or foundation on the seafloor. The foundation is held in place by piles either driven or sucked into the seafloor. This method dampens the vertical and rotational motions of the platform, but allows for horizontal movements. Tendons are typically steel tubes with dimensions of 2-3 foot in diameter with up to 3 inches of wall thickness, and lengths which depend on the water depth. Because of the excessive loads from wave, wind and current actions, tubular tendon components have to be manufactured by special technique with high cost materials such as titanium.
The two existing mooring systems fail to completely limit the movements of a floating platform and do so in a cost-effective manner. Accordingly, there is a present need for simple and inexpensive method for effectively anchoring a floating platform to the seabed. The present invention uses tendons which may be made from one or more wire cables or chains to tether the columns of a platform to the seabed. Each of the tendons are tensioned between the column and the anchor to limit motions of the platform in all directions.
All illustrations of the drawings are for the purpose of describing selected versions of the present invention and are not intended to limit the scope of the present invention.
With reference to
The present invention may be generally configured in one of two ways. In a first embodiment of the present invention, shown in
In both the first embodiment of present invention and the second embodiment of the present invention, the mooring assembly 6 further comprises a bell mouth 32. The bell mouth 32, shown in
In both the first embodiment of the present invention and the second embodiment of the present invention, the mooring assembly 6 can further comprise a second tendon 33 and a tendon joint 34. In reference to
In the first embodiment of the present invention, a number of different types of column couplers 7 may be used. In a first embodiment of the column coupler 7, the column coupler 7 is a bridge socket that can be adjusted in length to accommodate for an uneven seabed or the settling of the anchor 42. This is seen in
In a second embodiment of the column coupler 7, the column coupler 7 comprises a mounting bracket 8, a first pivot link 9, a second pivot link 10, a first rocker bracket 11, and a second rocker bracket 12. The mooring assembly 6 further comprises a protruding mount 39. In reference to
The second embodiment of the column coupler 7 is arranged in a specific manner to dampen the movements of the column 3 relative to the anchor 42. In this arrangement, a rotation axis 13 of the hinged connection between the first pivot link 9 and the mounting bracket 8 is oriented perpendicular to a rotation axis 14 of the hinged connection between the first pivot link 9 and the first rocker bracket 11. A rotation axis 15 of the hinged connection between the second pivot link 10 and the mounting bracket 8 is oriented perpendicular to a rotation axis 16 of the hinged connection between the second pivot link 10 and the second rocker bracket 12. The connection between the first pivot bar and the mounting bracket 8 and the connection between the second pivot bar and the mounting bracket 8 are both used to account for movements in a direction along the lateral portion 5 of the column 3. The connection between the first pivot link 9 and the first rocker bracket 11 and the connection between the second pivot link 10 and the second rocker bracket 12 are both used to account for movements either towards or away from the column 3. The rotation axis 13 of the hinged connection between the first pivot link 9 and the mounting bracket 8 is oriented parallel to the rotation axis 15 of the hinged connection between the second pivot link 10 and the mounting bracket 8. Overall, this arrangement allows for rotational control of the first tendon 27.
For the second embodiment of the column coupler 7 to work correctly, it is necessary that the first tendon 27 comprises a first wire cable 28 and a second wire cable 29, a third wire cable 30 and a fourth wire cable 31. The first wire cable 28 and the second wire cable 29 are each hingedly attached to the first rocker bracket 11. The first wire cable 28 and the second wire cable 29 are positioned opposite to each other along the first rocker bracket 11. The movements of the first wire cable 28 and the second wire cable 29 are dependent upon each other and account for half of the first tendon 27. The third wire cable 30 and the fourth wire cable 31 are each hingedly attached to the second rocker bracket 12. The third wire cable 30 and the fourth wire cable 31 are positioned opposite to each other along the second rocker bracket 12. The movements of the third wire cable 30 and the fourth wire cable 31 are dependent upon each other and account for half of the first tendon 27. The first wire cable 28 and the second wire cable 29, however, move independently from the third wire cable 30 and the fourth wire cable 31. This arrangement allows for the tension in the first wire cable 28, the second wire cable 29, the third wire cable 30, and the fourth wire cable 31 to equalize.
In a third embodiment of the column coupler 7, the column coupler 7 comprises a first pivot link 9, a second pivot link 10, a first stabilizing bracket 17, a second stabilizing bracket 18, a first swinging bracket 19, and a second swinging bracket 20. In reference to
Similar to the second embodiment of the column coupler 7, the third embodiment of the column coupler 7 is arranged in a specific manner to dampen the movements of the column 3. In this arrangement, a rotation axis 21 of the hinged connection between the first pivot link 9 and the protruding mount 39 is oriented parallel to a rotation axis 22 of the hinged connection between the second pivot link 10 and the protruding mount 39. The rotation axis 21 of the hinged connection between the first pivot link 9 and the protruding mount 39 is oriented parallel to a rotation axis 23 of the hinged connection between the first pivot link 9 and the first stabilizing bracket 17. The rotation axis 23 of the hinged connection between the first pivot link 9 and the first stabilizing bracket 17 is oriented parallel to a rotation axis 24 of the hinged connection between the second pivot link 10 and the first stabilizing bracket 17. The connection between the first pivot link 9 and the protruding mount 39 and the connection between the second pivot link 10 and the protruding mount 39 are both used to account for movements in a direction along the lateral portion 5 of the column 3. The rotation axis 23 of the hinged connection between the first pivot link 9 and the first stabilizing bracket 17 is oriented perpendicular to a rotation axis 25 of the hinged connection between the second stabilizing bracket 18 and the first swinging bracket 19. The rotation axis 25 of the hinged connection between the second stabilizing bracket 18 and the first swinging bracket 19 is oriented parallel to a rotation axis 26 of the hinged connection between the second stabilizing bracket 18 and the second swinging bracket 20. The connection between the first swinging bracket 19 and the second stabilizing bracket 18 and the connection between the second swinging bracket 20 and the second stabilizing bracket 18 are both used to account for movements either towards or away from the lateral portion 5 of the column 3. Overall, this arrangement allows for rotational control of the first tendon 27.
For the third embodiment of the column coupler 7 to work properly, it is necessary that the first tendon 27 comprises a first wire cable 28, a second wire cable 29, a third wire cable 30, and a fourth wire cable 31. The first wire cable 28 is attached adjacent to the first swinging bracket 19, opposite to the second stabilizing bracket 18. The second wire cable 29 is attached adjacent to the first swinging bracket 19, adjacent to the first wire cable 28. The movements of the first wire cable 28 and the second wire cable 29 are dependent upon each other and account for half of the first tendon 27. The third wire cable 30 is attached adjacent to the second swinging bracket 20, opposite to the second stabilizing bracket 18. The fourth wire cable 31 is attached adjacent to the second swinging bracket 20, adjacent to the third wire cable 30. The movements of the third wire cable 30 and the fourth wire cable 31 are dependent upon each other and account for half of the first tendon 27. The first wire cable 28 and the second wire cable 29, however, move independently from the third wire cable 30 and the fourth wire cable 31. This allows for better control of the positioning of the column 3 and results in a smaller response from the column 3 in the event that the anchor 42 settles itself on the seabed.
In the first embodiment of the present invention, a number of different embodiments for the first tendon 27 may be used. In a first embodiment of the first tendon 27, the first tendon 27 is a single tendon cable. This is shown in
In the second embodiment of the present invention, shown in
Although the invention has been explained in relation to its preferred embodiment, it is to be understood that many other possible modifications and variations can be made without departing from the spirit and scope of the invention as hereinafter claimed.
Claims
1. A tension-leg platform anchoring system comprises:
- a topside;
- a plurality of anchored floating supports;
- each of the plurality of anchored floating supports comprises a column, at least one mooring assembly, and an anchor;
- the mooring assembly comprises a column coupler, a first tendon, a second tendon, an anchor coupler, a tendon joint, a protruding mount;
- a first base of the column being mounted normal to the topside;
- the column coupler being mounted to the column;
- the anchor coupler being tethered to the column coupler by the first tendon;
- the first tendon being positioned adjacent and along a lateral portion of the column;
- the anchor being attached adjacent to the anchor coupler, opposite to the first tendon;
- the protruding mount being connected adjacent to the lateral portion, adjacent to the first base;
- the protruding mount and the column coupler being positioned opposite of each other across the first base;
- the column coupler being tethered to the tendon joint by the second tendon;
- the anchor coupler being tethered to the tendon joint by the first tendon;
2. The tension-leg platform anchoring system as claimed in claim 1, wherein the column coupler is mounted to the lateral portion of the column.
3. The tension-leg platform anchoring system as claimed in claim 1, wherein the column coupler is mounted onto the first base of the column.
4. The tension-leg platform anchoring system as claimed in claim 1 comprises:
- the mooring assembly further comprises a bell mouth;
- the bell mouth being connected adjacent to the lateral portion of the column;
- the bell mouth being positioned offset from the column coupler along the column; and
- the first tendon traversing through the bell mouth.
5. The tension-leg platform anchoring system as claimed in claim 1 comprises:
- the tendon joint comprises a first socket, a second socket, and a tendon link;
- the first socket being tethered to the anchor coupler by the first tendon;
- the second socket being tethered to the column coupler by the second tendon; and
- the first socket being engaged to the second socket through the tendon link.
6. The tension-leg platform anchoring system as claimed in claim 1, wherein the column coupler is a bridge socket.
7. The tension-leg platform anchoring system as claimed in claim 1, wherein the first tendon is a plurality of wire cables.
8. The tension-leg platform anchoring system as claimed in claim 1 comprises:
- the mooring assembly further comprises a sheave;
- the sheave being rotatably mounted onto the first base and the protruding mount; and
- the second tendon being tensionably engaged about the sheave.
9. The tension-leg platform anchoring system as claimed in claim 8 comprises:
- the mooring assembly further comprises a tendon adjustment cable and a pulley;
- the pulley being rotatably mounted to the first base, adjacent to the sheave;
- the column coupler being tethered to the tendon joint by the tendon adjustment cable; and
- the tendon adjustment cable being tensionably engaged about the pulley.
Type: Application
Filed: Dec 30, 2016
Publication Date: Apr 20, 2017
Inventor: Arcandra Tahar (Houston, TX)
Application Number: 15/395,342