Spiral-like anchor group installation system

Abstract

To disclose an offshore fixation system.SOLUTION: An offshore fixation system has two or more spiral-like anchors and each anchor has a prescribed length. The offshore fixation system has the two or more spiral-like anchors and a template functioning as the base to connect the two or more spiral-like anchors. Several embodiments have a skirt part extending in the direction substantially parallel to the longitudinal direction of the two or more spiral-like anchors from the outer periphery of the template and an additional horizontal support is provided by this.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] Government Rights This invention was made with government support under Contract No. DE-SC0017969, Project No. 2576 awarded by the Department of Energy, and the government has certain rights in this invention.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 939,239, entitled "Helical Anchor Group Installation System," filed November 22, 2019, the entire disclosure of which is incorporated herein by reference. Summary of the Invention [Means for solving the problem]

[0003] This specification discloses an offshore anchor system comprising two or more helical anchors, each anchor having a predetermined length, and a template that serves as a base for connecting the two or more helical anchors.

[0004] Some embodiments further include a skirt extending from the periphery of the template in a direction substantially parallel to the length of the two or more helical anchors to provide additional horizontal support.

[0005] In some embodiments, the skirt portion extends from the template in the same direction as the two or more helical anchors and extends from about 5% to about 50% of the length of the two or more helical anchors.

[0006] In some embodiments, the template and the skirt are separate pieces that can be assembled in the field.

[0007] In some embodiments, the offshore anchoring system comprises two or more helical anchors, each having a predetermined length; a template that functions as a base connecting the two or more helical anchors; and a skirt extending from the outer periphery of the template in a direction substantially parallel to the length of the two or more helical anchors, the skirt extending for a distance of approximately 5% to 50% of the length of the two or more helical anchors, thereby providing additional horizontal support.

[0008] Some embodiments provide a method of anchoring an offshore floating platform, the method comprising anchoring such an anchoring system to the seabed and mooring the floating platform to the anchoring system.

[0009] These and other aspects will become apparent from this disclosure. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram of a wind turbine and anchoring system according to one embodiment described herein. [Figure 2] FIG. 2 is a partial cutaway view of a fixation system described herein.

[0011] The drawings are for illustrative purposes only and are not necessarily to scale. DETAILED DESCRIPTION OF THE INVENTION

[0012] The demand for offshore wind farms is increasing, as is their availability. A key aspect of the success of such offshore wind farms is the secure anchoring of the turbines. Current anchoring solutions have become prohibitively large with the increasing number of turbines, resulting in installation problems, complicated transportation, and large-scale manufacturing. The present invention provides a solution for offshore wind farms that is easy to manufacture and transportable, while allowing for simplified installation at a lower overall cost. The proposed anchoring solution has one or more of the following advantages: low cost, ease of manufacture, low noise, ease of transportation, easier installation, etc.

[0013] Instead of large anchoring means, the proposed system employs multiple small, easily manufactured helical anchors that are closely spaced and combined with a template and optional skirt, a combination not previously used in the field of offshore floating wind power.

[0014] The system disclosed herein uses multiple small helical anchors, a template, and an optional skirt to provide the uplift and lateral capabilities needed to moor a floating wind power platform. The present invention consists of three components: helical anchors, a template, and an optional skirt, providing the capabilities needed for the floating wind power industry. The anchoring system is installed by a subsea remote tool. The helical anchors provide the majority of the uplift capacity of the system. The helical anchors are installed by applying torque and downforce and screwing into the seabed. Site-specific soil conditions determine the style, size, and length of the helical anchors that provide optimal performance. The template is a base platform that holds all the helical anchors and provides the mooring connection to the floating platform, or a base platform to which rigid components are connected. The template also provides a base for the subsea tool to sit on while installing each anchor. The template provides some flotation and lateral capacity, but its effect is relatively small compared to the overall system. The primary purpose of the template is to provide stability and transfer loads from the mooring connection points to the anchors. The skirt increases the lateral capacity of the system.

[0015] Each helical anchor includes a shaft and a helical plate. The shafts may range in length from approximately 5 to 20 feet and may be connected by a coupling device. The helical plate is designed and positioned to twist the anchor, thereby moving the shaft downward into the seabed. Multiple anchors can be simultaneously employed in a single anchoring system via a template.

[0016] The template has a base made of any suitable material, such as, but not limited to, concrete and / or metal. The template engages with each of the anchors in the plurality of anchors, connecting them as a whole system. The template and anchors can be transported separately and assembled on-site, allowing for ease of transportation, use, and installation, as well as the ability to resize according to site needs.

[0017] The skirt has an outer shell of varying size and thickness attached to the periphery of the template, the outer shell being made of any suitable material, including but not limited to metal, stone, or concrete.

[0018] Figure 1 shows a schematic diagram of a single wind turbine moored to the seabed using the anchoring system described herein. As shown, the wind turbine is attached to a floating platform at or near the waterline; any turbine and floating device can be used. A variety of turbines (single or multiple) and floating devices (e.g., floating platforms, Dutch tri-floaters, barges, spars, monohulls, TLPs, etc.) can be used with the anchoring systems described herein.

[0019] The floating platform is attached to one or more anchorage systems by one or more mooring lines.

[0020] Each anchoring system includes a plurality of helical anchors, each embedded in the seabed and connected to a template. The template is provided with a skirt around its periphery, which is also embedded in the seabed to provide additional horizontal support. The depth of the skirt, along with the helical anchors, is determined individually depending on factors such as the depth of the installation site, seabed composition, ocean currents, and other considerations. In some embodiments, the skirt may extend into the seabed up to 5% of the length of the anchor shaft, and in some embodiments, the skirt may extend into the seabed up to 10%, 15%, 20%, 25%, 30%, 40%, or 50% of the length of the anchor shaft.

[0021] The template is circular and the accompanying skirt is a hollow cylinder, as shown in Figure 2. Any shape can be used for the template, including oval, square, rectangular, etc., and its sidewalls can be extended to form a skirt having a complementary shape.

[0022] As shown, a single mooring connection and mooring line is attached to the template, however, in some embodiments, multiple mooring lines may be attached to the template.

[0023] The combination of multiple helical anchors, templates, and optional skirts can create a stable fixation device that is easy to manufacture, transport, and install.

[0024] In some embodiments, two or more anchoring systems may be used to moor the same platform.

[0025] These and other embodiments will become apparent to those skilled in the art upon reading this specification without departing from the scope and spirit of the present disclosure.

[0026] The cost of anchoring offshore floating wind turbines presents an obstacle to reducing energy production costs and providing savings opportunities for floating wind turbine projects. The deep waters of West Coast sites further increase costs. Traditional anchoring systems use large, heavy weights, casings, or high pulling and embedding forces to achieve the high towing forces required for mooring. The heavy weights and forces ultimately contribute to high costs. This paper proposes a robust anchoring system that requires low installation forces and can be remotely controlled from a general-purpose marine vessel. This technique has been adopted as a cost-saving measure for deepwater seabed characterization, providing similar savings in mooring installation costs. This anchoring technique is scalable and applicable to a variety of subsea infrastructures beyond offshore wind, including oil and gas, pipelines, and other renewable energy systems. In addition to the public benefit of low-cost green energy, this system minimizes noise impact on the environment.

[0027] The following are appendices to the present disclosure. (Additional note 1) 1. An offshore fixed system comprising: two or more helical anchors, each anchor having a predetermined length; and a template that serves as a base for connecting the two or more helical anchors; An offshore fixed system having: (Additional note 2) The offshore fixed system according to Supplementary paragraph 1 further comprises: an offshore anchoring system having a skirt portion extending from the outer periphery of the template in a direction substantially parallel to the length of the two or more helical anchors, thereby providing additional horizontal support. (Additional note 3) In the offshore anchoring system described in Supplementary Item 2, the skirt portion extends from the template in the same direction as the two or more helical anchors and extends to about 5% to about 50% of the length of the two or more helical anchors. (Additional note 4) 3. The offshore fastening system according to claim 2, wherein the template and the skirt portion are independent components that can be assembled on site. (Additional note 5) 5. The offshore fastening system according to claim 4, wherein the template and the skirt portion are uniform structures. (Additional note 6) In the offshore fastening system described in appended claim 1, the template further comprises a metal template having connection points for each of the two or more helical anchors, whereby each helical anchor is permanently connected to the template. (Additional note 7) 2. The offshore fixing system according to claim 1, wherein each helical anchor has a shaft and a helical plate. (Additional note 8) 8. The offshore fastening system according to claim 7, wherein the helical anchors are substantially parallel to each other. (Additional note 9) 8. The offshore anchoring system according to claim 7, wherein at least one of the two or more helical anchors is not parallel to at least one other of the two or more helical anchors. (Additional note 10) 2. The offshore fastening system according to claim 1, wherein the shaft of each helical anchor passes through the template and is fixed to the template. (Additional note 11) 1. An offshore fixed system comprising: two or more helical anchors, each anchor having a predetermined length; and a template that serves as a base for connecting the two or more helical anchors; a skirt portion extending from the outer periphery of the template in a direction substantially parallel to the length of the two or more helical anchors, the skirt portion extending a distance of about 5% to about 50% of the length of the two or more helical anchors, thereby providing additional horizontal support; and An offshore fixed system having: (Additional note 12) An offshore mooring system having two or more helical anchors as described in appended paragraph 1. (Additional note 13) 1. A method for anchoring an offshore floating platform, comprising: anchoring the template to the seabed with one or more helical anchors, the one or more helical anchors passing through and secured to the template; mooring the floating platform to the template with mooring lines; A method comprising: (Additional note 14) The method according to Supplementary Item 13, further comprising: providing a skirt extending from a periphery of the template into the seabed. (Additional note 15) 15. The method of claim 14, wherein the skirt extends into the seabed by about 5% to about 50% of the length of the one or more helical anchors.

Claims

1. 1. A fastening system comprising: at least one anchor; a skirt surrounding the at least one anchor and configured to be embedded in the seabed to provide horizontal support; A fastening system comprising:

2. The fastening system of claim 1 , wherein the skirt is made of a material including one or more of metal, stone, or concrete.

3. 10. The fastening system of claim 1, further comprising a template configured to serve as a support for an installation tool, the template serving as a base for aligning and connecting the at least one anchor.

4. The fixation system of claim 3 , wherein the skirt extends from the periphery of the template in a direction parallel to the length of the at least one anchor, thereby providing additional horizontal support.

5. The fastening system of claim 3 , wherein the skirt comprises an outer shell attached to a periphery of the template.

6. The fastening system of claim 1 , wherein the skirt extends from 10% to 50% of the length of the anchor shaft.

7. The anchoring system of claim 1 , wherein the skirt is configured to extend into the seabed between 0% and 5% of the length of the anchor shaft.

8. The anchoring system of claim 1 further comprising at least one mooring line.

9. 9. The anchoring system of claim 8, wherein at least one floating device is attached to said at least one mooring line.

10. The fastening system of claim 1 , wherein the template comprises a base portion made of concrete and / or metal.

11. 1. A method of installing a fastening system, comprising: embedding a plurality of anchors in the seabed; using an installation tool to couple the anchors to a template through which the shaft of each anchor passes, the template serving as a base for aligning and coupling the anchors and as a support for the installation tool; A method comprising:

12. The method of claim 11 further comprising providing a skirt surrounding each of the plurality of anchors.

13. 13. The method of claim 12, wherein the skirt is made of a material including one or more of metal, stone, or concrete.

14. 13. The method of claim 12, wherein the skirt extends from the periphery of the template in a direction parallel to the length of the anchors, thereby providing additional horizontal support.

15. The method of claim 12 , wherein the skirt portion has a shape complementary to the template.

16. The method of claim 11 , wherein the anchors are parallel to one another.

17. The method of claim 11 , wherein the installation tool is a subsea remote tool.

18. 12. The method of claim 11, wherein the securing system further comprises at least one mooring line and at least one floating device attached to the at least one mooring line.

19. The method of claim 11 , wherein at least one of the plurality of anchors is a helical anchor.

20. 1. A fastening system comprising: at least one anchor; a template through which the shaft of the at least one anchor passes and which serves as a base for aligning and connecting the anchor and as a support for an installation tool; a skirt surrounding the template and configured to be embedded in the seabed to provide horizontal support; A fastening system comprising:

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