Spiral anchor group installation system

Abstract

SOLUTION: This specification discloses an offshore anchoring system comprising two or more helical anchors, each anchor having a length, and a template acting as a base connecting the two or more helical anchors. Some embodiments further comprise a skirt extending from an 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.

Description

Technical Field

[0001] Government Rights This invention was made with government support under Contract No. DE-SC0017969 and Project No. 2576, authorized 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, filed on November 22, 2019, entitled "Helical Anchor Group Installation System", the entire disclosure of which is incorporated herein by reference. As prior art document information related to the invention of this application, there are the following (including documents cited at the international stage after the international filing date and documents cited when transferred to other countries). (Prior art document) (Patent document) (Patent Document 1) Korean Patent Publication No. 2015-0021226 (Patent Document 2) US Patent Application Publication No. 2017 / 0174294 (Patent Document 3) US Patent No. 6,665,990 (Patent Document 4) US Patent Application Publication No. 2010 / 0135729 (Patent Document 5) Chinese Patent No. 101705920 (Patent Document 6) US Patent Application Publication No. 2019 / 0271131 (Patent Document 7) US Patent Application Publication No. 2005 / 0229836 (Patent Document 8) US Patent No. 8,729,723 (Patent Document 9) US Patent Application Publication No. 2011 / 0074155

Summary of the Invention

Means for Solving the Problems

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

[0004] Some embodiments further include a skirt portion extending from an outer peripheral portion of the template in a direction substantially parallel to the longitudinal direction of the two or more helical anchors, thereby providing 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 portion are independent components that can be assembled on site.

[0007] In some embodiments, the offshore fixing system includes two or more helical anchors, each anchor having a predetermined length, the two or more helical anchors, a template functioning as a base connecting the two or more helical anchors, and a skirt portion extending from an outer peripheral portion of the template in a direction substantially parallel to the longitudinal direction of the two or more helical anchors and extending a distance of about 5% to 50% of the length of the two or more helical anchors, thereby providing additional horizontal support.

[0008] Some embodiments provide a method for fixing an offshore floating platform, the method including the steps of fixing such a fixing system to the seabed and mooring the floating platform to the fixing system.

[0009] The above aspects and other aspects will be apparent from the present disclosure.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

[0011] This drawing is for illustrative purposes only and is not necessarily to scale.

Mode for Carrying Out the Invention

[0012] The demand for offshore wind power plants is increasing along with their practicality. An important point in the success of such offshore wind power plants is to securely fix the turbines. Current fixing means have become extremely large with the increase in turbines, resulting in installation problems, transportation complexity, and large-scale manufacturing. The present invention provides a solution means for offshore wind power plants that is easy to manufacture and transport, and that can reduce the overall cost and enable simple installation. The proposed fixing means has one or more advantages such as low cost, ease of manufacturing, low noise, ease of transportation, and simpler installation.

[0013] Instead of large fixing means, in the proposed system, a plurality of small and easily manufacturable helical anchors are employed, and the helical anchors are arranged in proximity and combined with a template and an optional skirt portion. Such a combination has not been used in the field of floating offshore wind power.

[0014] The system disclosed in this specification uses a plurality of small helical anchors, a template, and an optional skirt to provide the lifting and horizontal capabilities required to moor a floating wind power platform. The present invention is composed of three components: a helical anchor, a template, and an optional skirt, and provides the capabilities required in the field of floating wind power. This fixed system is installed by a remote tool in the sea. The helical anchor provides most of the lifting capacity in the system. The helical anchor is installed by applying torque and a downward force (downforce) and screwing it into the seabed. Depending on the site-specific soil conditions, the style, size, and length of the helical anchor that provides optimal performance are determined. The template is a base platform that holds all the helical anchors and provides a mooring connection to the floating platform, or a base platform to which a rigid component is connected. Also, the template provides a base on which the subsea tool seats while installing each anchor. The template provides some lifting and horizontal capabilities, but its effect is relatively small compared to the entire system. The main purpose of the template is to provide stability and transfer the load from the mooring connection point to each anchor. The skirt increases the horizontal capacity of the system.

[0015] Each helical anchor has a shaft and a helical plate. The shaft length ranges from about 5 to 20 feet and may be connected by a connecting device. The helical plate is designed and arranged to move the shaft downward into the seabed by screwing the anchor in. In a single fixed system, multiple anchors can be employed simultaneously through the 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 a plurality of anchors and connects each anchor as an overall one system. The template and the anchors can be transported individually and assembled on site, which facilitates transportation, use, and installation and enables size modification according to on-site requirements.

[0017] The skirt portion has outer shells of different sizes and thicknesses attached to the outer peripheral portion of the template, and the outer shells are made of any suitable material including, but not limited to, metal, stone, or concrete.

[0018] FIG. 1 shows a schematic view of a single wind turbine moored to the seabed using the fixing system described in this specification. As shown, the wind turbine is attached to a floating platform above or near the waterline, and any turbine and floating device can be used. Together with the fixing system described in this specification, various turbines and floating devices (such as floating platforms, Dutch tri-floaters, barges, round logs, single-hull ships, TLPs, etc.) can be used.

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

[0020] Each fixing system has a plurality of helical anchors, and each anchor is embedded in the seabed and connected to the template. A skirt portion is provided on the outer peripheral portion of the template, and this skirt portion is also embedded in the seabed to provide additional horizontal support. The depth of the skirt portion together with the helical anchor is determined individually according to factors such as the depth of the installation site, the seabed composition, ocean currents, and other considerations. In some embodiments, the skirt portion may extend into the seabed up to 5% of the length of the anchor shaft, and in some embodiments, the skirt portion may extend into the seabed up to 10%, 15%, 20%, 25%, 30%, 40%, or 50% of the length of the anchor shaft.

[0021] As shown in FIG. 2, the template is circular, and the accompanying skirt portion is a hollow cylindrical body. For the template, any shape can be used, including an ellipse, a square, a rectangle, etc., and its side walls can be extended to form a skirt portion having a complementary shape.

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

[0023] A combination of a plurality of helical anchors, a template, and an optional skirt portion can produce a stable fixing device that is easy to manufacture, transport, and install.

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

[0025] Those skilled in the art who have read this specification will consider the above embodiments and other embodiments to be self-evident without departing from the scope and gist of the present disclosure.

[0026] The cost of fixing floating wind turbines is an obstacle to reducing the energy production cost of floating wind turbine projects and providing opportunities for savings. Since the sites on the west coast are in deep sea, the cost further increases. In conventional fixing systems, large, heavy weights, casings, or high traction and embedding forces are used to achieve the high traction required for mooring. The heavy weights and the said forces ultimately result in high costs. This document proposes a robust fixing system that can be installed with a small force and can be remotely controlled from a general ocean vessel. This technique has been adopted as a cost-saving means for undersea property surveys in deep sea and can provide similar cost savings in mooring installation costs. This fixing technique can be sized and applied to a variety of subsea bases beyond offshore wind power, such as oil and gas, pipelines, and other renewable energy systems. In addition to the public good provided by low-cost green energy, the noise impact on the environment is minimized in this system.

Claims

**Claim 1** An offshore fixing system comprising: two or more helical anchors, each anchor having a predetermined length, said two or more helical anchors; a template through which the shafts of each helical anchor penetrate, functioning as a base for aligning and connecting said two or more helical anchors and as a support for installation; and an offshore fixing system applicable for installation and use in deep sea. **Claim 2** The offshore fixing system according to Claim 1, further comprising: a skirt portion extending from the outer peripheral portion of the template in a direction parallel to the longitudinal direction of said two or more helical anchors, thereby providing additional horizontal support, the offshore fixing system. **Claim 3** The offshore fixing system according to Claim 2, wherein the skirt portion extends from the template in the same direction as said two or more helical anchors and extends up to 5% to 50% of the length of said two or more helical anchors, the offshore fixing system. **Claim 4** The offshore fixing system according to Claim 2, wherein the template and the skirt portion are independent components that can be assembled on site, the offshore fixing system. **Claim 5** The offshore fixing system according to Claim 4, wherein the template and the skirt portion are of uniform structure, the offshore fixing system. **Claim 6** The offshore fixing system according to Claim 1, wherein the template further comprises a metal template having connection points for each of said two or more helical anchors, whereby each helical anchor is permanently connected to the template, the offshore fixing system. **Claim 7** The offshore fixing system according to Claim 1, wherein each helical anchor is parallel to each other, the offshore fixing system. **Claim 8** The offshore fixing system according to Claim 1, wherein at least one of said two or more helical anchors is not parallel to at least another one of said two or more helical anchors, the offshore fixing system. **Claim 9** An offshore fixing system comprising: two or more helical anchors, each anchor having a predetermined length, said two or more helical anchors; A template that functions as a base for connecting the two or more helical anchors through which the shafts of the respective helical anchors are penetrated and fixed A skirt portion extending from the outer peripheral portion of the template in a direction parallel to the longitudinal direction of the two or more helical anchors, extending to a distance of 5% to 50% of the length of the two or more helical anchors, thereby providing additional horizontal support, the skirt portion having An offshore fixing system applicable for installation and use in deep sea.

10. An offshore mooring system having the offshore fixing system according to claim 1 of two or more claims.

11. A method for fixing an offshore floating body type platform, A step of fixing a template to the seabed by one or more helical anchors, wherein the one or more helical anchors penetrate the template and are fixed to the template, the fixing step A step of mooring the offshore floating body type platform to the template by a mooring cable having

12. In the method according to claim 11, further A method having a step of providing a skirt portion extending from the outer peripheral portion of the template into the seabed.

13. In the method according to claim 12, the skirt portion extends into the seabed to 5% to 50% of the length of the one or more helical anchors.

14. An offshore fixing system, having a shaft and a helical plate, two or more helical anchors having a predetermined length, A template that supports a subsea tool and functions as a base for connecting the two or more helical anchors, A skirt portion extending from the outer peripheral portion of the template in a direction parallel to the longitudinal direction of the two or more helical anchors, thereby providing additional support in the longitudinal direction, extending to 5% to 50% of the length of the two or more helical anchors, and forming a hollow space together with the template, having the skirt portion The shaft of each helical anchor penetrates the template and is fixed to the template, An offshore fixing system applicable for installation and use in deep sea.

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