Floating platform including a vertically positioned mooring system

Abstract

An offshore floating platform system and a process for mooring the same. In some embodiments, the offshore floating platform system can include a hull structure configured to float on the surface of a body of water, one or more anchors configured to be secured to the seabed, and one or more mooring lines connected to the hull structure at a first end thereof and to the anchors at a second end thereof. When the one or more anchors are secured to the seabed and the one or more mooring lines are connected to the hull structure and the corresponding anchors, the mooring lines can be substantially vertical, and a peak response period of the offshore floating platform system in a pitch or roll direction can be greater than a peak spectral period of a wave spectrum on the surface of the body of water.

Description

[Technical Field]

[0001] The described embodiments relate generally to offshore floating platform systems, and more particularly to floating platforms moored at offshore locations, such as at offshore wind farms or drilling sites, that include vertically arranged mooring systems. [Background technology]

[0002] In the offshore renewable industry, for example, the offshore floating wind industry, it is often necessary or desirable to moor platforms using vertically positioned mooring systems. Vertically positioned mooring systems generally have a smaller footprint than traditional spread mooring systems. Several platform configurations, such as tension leg platforms (TLPs), are available and are used in oil and gas applications. Such systems typically utilize vertically positioned steel pipe tendons as the mooring system to anchor the platform to the seabed. Such systems can be expensive and difficult to install. Summary of the Invention [Problem to be solved by the invention]

[0003] Therefore, there is a need for an improved vertically positioned mooring system for floating platforms in offshore locations. [Means for solving the problem]

[0004] An offshore floating platform system and a process for mooring an offshore platform are provided. In some embodiments, the offshore floating platform system can include a hull structure configured to float on the surface of a body of water, an anchor configured to be secured to the seabed, and a mooring line connected to the hull structure at a first end and to the anchor at a second end. When the anchor is secured to the seabed and the mooring line is connected to the hull structure and the anchor, the mooring line can be substantially vertical, and a peak response period of the offshore floating platform system in a pitch or roll direction can be greater than a peak spectral period of a wave spectrum on the surface of the body of water.

[0005] In some examples, a process for mooring an offshore platform may include providing an offshore floating platform including a hull structure configured to float on the surface of a body of water, an anchor configured to be secured to the seabed, and a mooring line configured to connect to the hull structure and the anchor. The process may also include securing the anchor to the seabed. The process may also include connecting a first end of the mooring line to the hull structure and a second end of the mooring line to the anchor. When the anchor is secured to the seabed and the mooring line is connected to the hull structure and the anchor, the mooring line may be substantially vertical, and a peak response period of the offshore floating platform system in a pitch direction or a roll direction may be greater than a peak spectral period of a wave spectrum on the surface of the body of water.

[0006] Various aspects and advantages of preferred embodiments of the present invention will become apparent to those skilled in the art upon reading the following detailed description of the invention, when read in light of the accompanying drawings, which form a part hereof. [Brief explanation of the drawings]

[0007] [Figure 1]FIG. 1 is an elevation view of an exemplary offshore floating platform system including a hull structure and a vertically positioned mooring system, according to one or more described embodiments. [Figure 2] FIG. 1 is an elevation view of another exemplary offshore floating platform system including a triangular hull structure and a vertically positioned mooring system, according to one or more described embodiments. [Figure 3] FIG. 3 is a plan view of the exemplary offshore floating platform system shown in FIG. 2. [Figure 4] FIG. 4 is an isometric view of the exemplary offshore floating platform system shown in FIGS. 2 and 3. [Figure 5] FIG. 10 graphically illustrates an exemplary set of curves including a response amplitude operator (RAO) in the heave direction and a RAO in the pitch or roll direction for an offshore floating platform system and a wave spectrum on the surface of a body of water, according to one or more described embodiments. [Figure 6] FIG. 10 graphically illustrates another example set of curves including RAO in the heave direction and RAO in the pitch or roll direction for another offshore floating platform system and a wave spectrum on the surface of a body of water, according to one or more described embodiments. [Figure 7] FIG. 5 is an isometric view of an exemplary offshore floating platform system similar to that shown in FIGS. 2-4, further including an optional wind turbine generator system disposed on the hull structure, according to one or more embodiments described. DETAILED DESCRIPTION OF THE INVENTION

[0008] A detailed description of the invention is provided below. Each claim in the following set forth claims defines a separate invention, which for infringement purposes is to be recognized as including equivalents to the various elements or limitations specified in the claim. Depending on the context, all references to the "invention" may, in some cases, refer only to certain specific or preferred embodiments. In other cases, references to the "invention" may refer to the subject matter recited in one or more, but not necessarily all, of the claims. It should be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functionality of the present invention. To simplify the disclosure, exemplary embodiments of components, arrangements, and configurations are described below; however, these exemplary embodiments are provided by way of illustration only and do not limit the scope of the invention. Furthermore, the present disclosure may repeat reference numerals and / or letters in the various exemplary embodiments and throughout the figures provided herein. This repetition is for simplicity and clarity and does not, in itself, dictate a relationship between the various exemplary embodiments and / or configurations illustrated in the figures. Furthermore, in the following description, forming a first feature over or on a second feature includes embodiments in which the first feature and the second feature are formed in direct contact with each other, and also includes embodiments in which an additional feature is formed between the first feature and the second feature such that the first feature and the second feature are not in direct contact with each other. The exemplary embodiments presented below may be combined in any combination without departing from the scope of the present disclosure, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment. The figures are not necessarily drawn to scale, and some features and some perspectives of the figures may be shown exaggerated in scale or in schematic views for clarity and / or conciseness.

[0009] Furthermore, throughout the following description and claims, certain terms are used to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and therefore, the naming conventions for the components described herein are not intended to limit the scope of the invention unless otherwise defined herein. Furthermore, the naming conventions used herein are not intended to distinguish between components that differ in name but not function. Furthermore, in the following description and in the claims, the terms "including" and "comprising" are used open-ended and, therefore, should be interpreted to mean "including, but not limited to."

[0010] All numerical values ​​in this disclosure are exact or approximate ("about") unless expressly stated otherwise. Thus, various embodiments of the present disclosure can deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope.

[0011] Furthermore, the term "or" is intended to encompass both exclusive and inclusive cases, i.e., "A or B" is intended to be synonymous with "at least one of A and B," unless expressly specified otherwise herein. The indefinite articles "a" and "an" refer to both singular (i.e., "one") and plural (i.e., one or more) objects unless the context clearly dictates otherwise. As used herein, the terms "up" and "down," "upward" and "downward," "upper" and "lower," "upwardly" and "downwardly," "above" and "below," and other similar terms, refer to relative positions with respect to one another and do not imply a particular spatial orientation, as the devices and processes for using them may be equally effective at various angles or orientations.

[0012] The terms "resonance" and "resonate" refer to the phenomenon of increased amplitude that occurs when the period of an applied periodic force (or its Fourier components) is equal to or close to the natural period of the offshore floating platform system on which the force acts. When an oscillatory force is applied at the resonant period of a dynamic offshore floating platform system, the system vibrates with a higher amplitude than when the same force is applied at other non-resonant periods of the dynamic offshore floating platform system. The period at which the response amplitude operator is greatest is also known as the resonant period of the offshore floating platform system. Small periodic forces close to the resonant period of an offshore floating platform system can result in large amplitude vibrations in the system due to the accumulation of vibrational energy.

[0013] The term "response amplitude operator" or "RAO" is a parameter or set of parameters used to determine the motion behavior of an offshore floating platform system under floating conditions. Thus, the RAO is a transfer function used to determine the effect that incident waves will have on the motion of an offshore floating platform system. In offshore engineering, the RAO may be represented in graphical form as the motion response of an offshore floating platform system for a particular degree of freedom plotted against the period of the incident waves. The highest value of the RAO of an oscillating offshore floating platform system may then be defined as the peak response period, which may also be referred to as the natural period of the system or the resonant period of the system.

[0014] The term "met-ocean conditions" refers to the conditions at the site where an offshore floating platform system is located. Meteorological conditions may include any combination of wind, waves, swell, currents, squalls, tropical storms, and storm surge conditions, which may impose forces on an offshore floating platform system.

[0015] The terms "peak spectral energy period" and "peak spectral period" refer to the wave period associated with the most energetic waves in the wave spectrum on the surface of a body of water.

[0016] The term "cancellation period" refers to a period during which the heave motion of an offshore floating platform system is minimized by balancing the wave forces acting on the pontoons of the offshore floating platform system with the wave forces acting on the columns of the offshore floating platform system. The wave forces acting on the pontoons of the offshore floating platform system may be substantially caused by water particle acceleration and therefore may be in the opposite phase to the incident waves, while the wave forces acting on the columns of the offshore floating platform system may be substantially caused by wave pressure (Froude-Krylov force) and therefore may be substantially in phase with the incident waves. For this reason, the heave motion of an offshore floating platform system may be minimized in the cancellation period.

[0017] 1 illustrates an elevation view of an exemplary offshore floating platform system 100 including a hull structure 110 and a vertically positioned mooring system 120 according to one or more embodiments. In some embodiments, the hull structure 110 may be configured to float on the surface 103 of a body of water 101 and may be exposed to weather and ocean conditions, such as wind, currents, and waves, such that the floating platform system 100 may move in response to the weather and ocean conditions. In some embodiments, the hull structure 110 may be any type of structure, including a semi-submersible hull, a barge-type hull, a spar-type hull, a ship-type hull, or any other type of hull configuration. In some embodiments, the hull structure may be a concrete structure, an engineered metal, e.g., steel structure, or a combination thereof. In some embodiments, hull structure 110 can include at least one column (two shown / visible in FIG. 1 ) 111, 112, at least one pontoon (one shown / visible in FIG. 1 ) 114, and a deck structure 115 that can be supported by the column(s) 111, 112. In some embodiments, hull structure 110 can include three columns and three pontoons. In some embodiments, hull structure 110 can include four columns and four pontoons. In some embodiments, hull structure 110 can include four or more columns and four or more pontoons.

[0018] In some embodiments, the vertically positioned mooring system 120 may be configured to maintain the hull structure 110 within specified tolerances in a lateral direction, i.e., in a surge direction and / or a sway direction and / or a yaw direction, when the offshore floating platform system 100 is subjected to meteorological and oceanographic conditions. In some embodiments, the vertically positioned mooring system 120 may include one or more mooring lines 131 and one or more anchors 121. A first end of the mooring line 131 may be configured to be connected to the hull structure 110, and a second end of the mooring line 131 may be configured to be connected to the anchor 121. In some embodiments, the vertically positioned mooring system 120 may include a plurality of mooring lines 131, for example, two, three, four, five, six, seven, eight, nine, ten, eleven, twelve, or more.

[0019] In some embodiments, the vertically positioned mooring system 120 is configured such that the mooring line(s) 131 can be vertical or substantially vertical when the floating platform system 100 is in a neutral state or position. The neutral state or position refers to the position of the floating platform system 100 when the floating platform system 100 is not exposed to weather and ocean conditions. The term "substantially vertical" means that the mooring line(s) 131 can be oriented within 0.5 degrees, 1 degree, 3 degrees, 5 degrees, 7 degrees, 9 degrees, 11 degrees, 13 degrees, 15 degrees, 17 degrees, or 20 degrees of an axis that is perpendicular to the ground. In some embodiments, when the mooring line(s) are substantially vertical, the mooring line(s) 131 may be oriented within ≦20 degrees, ≦18 degrees, ≦16 degrees, ≦14 degrees, ≦12 degrees, ≦10 degrees, ≦8 degrees, ≦6 degrees, ≦4 degrees, or ≦2 degrees of an axis that is perpendicular to the ground.

[0020] In some embodiments, the mooring line(s) 131 can be formed from a synthetic rope. In some embodiments, the synthetic rope can be a synthetic polymer rope. In some embodiments, the synthetic polymer comprising the synthetic polymer rope can be or include, but is not limited to, polyester, nylon, ultra-high-molecular-weight polyethylene (UHMWPE), or any combination thereof. In other embodiments, at least a portion of the mooring line(s) 131 can be formed from a synthetic rope, and at least a portion of the mooring line(s) 131 can be formed from wire rope and / or chain and / or other elongated members. In some embodiments, the mooring line 131 may be composed of one or more segments of polyester rope, such as DEEPROPE® polyester rope sold by Bexco, or MOORLINE® polyester rope sold by Bridon, or CABRAL 512® polyester rope sold by Lankhorst, or DYNEEMA® UHMWPE rope sold by DSM, or any other synthetic rope having suitable properties.

[0021] The one or more anchors 121 may be configured to be secured to the seabed 105. In some examples, the anchors 121 may be configured to transfer lift forces, lateral forces, or a combination thereof from the mooring lines 131 to the seabed 105. In some examples, the anchors 121 may be suction piles, driven piles, gravity anchors, or a combination thereof. The particular configuration of the anchors 121 may be based at least in part on the type of seabed 105 at the site, e.g., soil conditions, and the loads expected to be exerted on the anchors 121 when connected to the hull structure 110 via the mooring lines 131.

[0022] In some embodiments, when the hull structure 110 and one or more anchors 121 are connected to one another via one or more mooring lines 131, the mooring line(s) 131 may include a pretension so that the mooring line(s) 131 may always be in tension when the hull structure 110 moves when the system 100 is exposed to weather and sea conditions. In some embodiments, the pretension may be selected to avoid snap loads on the mooring line(s) 131. In some embodiments, the pretension may be about 50 tons, about 100 tons, about 150 tons, about 200 tons, about 225 tons, about 250 tons, about 300 tons, about 350 tons, about 400 tons to about 450 tons, about 500 tons, about 550 tons, or more. In some examples, the pretension can be between about 225 tons and about 300 tons, between about 300 tons and about 450 tons, or between about 450 tons and about 550 tons. The selection of the pretension of the mooring line(s) 131 can be based at least in part on the expected weather and ocean conditions at the site, the water depth, the characteristics of the mooring line(s) 131, the dimensions of the hull structure 110, or any combination thereof.

[0023] In some embodiments, the length of the mooring line(s) 131 may be determined so that a desired pre-tension can be provided upon connection to the hull structure 110 and anchor 121. In other embodiments, a segment of wire rope or chain may be used to connect a first end of the mooring line 131 to the hull structure 110 and / or a second end of the mooring line 131 to the anchor 121. In such embodiments, the segment of wire rope or chain may be used to apply pre-tension in the mooring line 131. In such embodiments, the segment of wire rope or chain may also be used to adjust the pre-tension in the mooring line 131. For example, over time, the pre-tension may decrease due to elongation of the synthetic rope, and after a period of time, the length of the wire rope and / or chain between the synthetic rope and anchor 121 and / or between the synthetic rope and hull structure 110 may be reduced to increase the pre-tension. In other embodiments, the mooring line(s) 131 may be connected to the anchor 121 and / or the hull structure 110 via length-adjustable connectors.

[0024] In some embodiments, the vertical distance between the surface 103 of the body of water 101 and the ocean floor 105 may be referred to as the water depth. In some embodiments, the water depth may be about 100 meters, about 200 meters, about 300 meters, about 400 meters, or about 500 meters to about 600 meters, about 700 meters, about 800 meters, about 900 meters, about 1,000 meters, about 1,200 meters, about 1,400 meters, or more. In some embodiments, the water depth may be about 200 meters to about 300 meters, about 300 meters to about 500 meters, or about 500 meters to about 1,000 meters, or more than 1,000 meters.

[0025] 2, 3, and 4 show elevation, plan, and isometric views, respectively, of an exemplary offshore floating platform system 200 including a semi-submersible triangular hull structure 210 and a vertically positioned mooring system 220, according to one or more embodiments. In some embodiments, hull structure 210 may float on the surface 203 of a body of water 201 and may be exposed to weather and ocean conditions, which may impart forces to floating platform system 200. In some embodiments, hull structure 210 may include a first column 211, a second column 212, and a third column 213. In some embodiments, first column 211, second column 212, and third column 213 may be fabricated steel construction, steel reinforced concrete construction, or a combination thereof. In some embodiments, the first column 211, the second column 212, and the third column 213 may be arranged in a triangular configuration when viewed in plan view.

[0026] In some embodiments, hull structure 210 may include first pontoon 214, second pontoon 215, and third pontoon 216. In some embodiments, first column 211 may be connected to second column 212 via first pontoon 214, second column 212 may be connected to third column 213 via second pontoon 215, and third column 213 may be connected to first column 211 via third pontoon 216. First pontoon 214, second pontoon 215, and third pontoon 216 may be connected toward or at first or lower ends of columns 211, 212, 213. In some embodiments, first pontoon 214, second pontoon 215, and third pontoon 216 may be disposed at least partially below the surface of body of water 201. In some implementations, first pontoon 214, second pontoon 215, and third pontoon 216 may be fabricated steel construction, steel-reinforced concrete construction, or a combination thereof.

[0027] In some embodiments, first column 211, second column 212, and third column 213 may be rigidly or fixedly connected to one another via structural frame 217. Structural frame 217 may be connected toward or at the second or upper ends of columns 211, 212, and 213. In some embodiments, structural frame 217 may be disposed above surface 203 of body of water 201. In some embodiments, structural frame 217 may be fabricated steel structure, steel-reinforced concrete structure, or a combination thereof.

[0028] Hull structure 210 may be configured to connect to vertical mooring system 220. In some embodiments, first column 211, second column 212, and third column 213 may each be configured to connect to one or more corresponding mooring lines. In other embodiments, first pontoon 214, second pontoon 215, and third pontoon 216 may each be configured to connect to one or more corresponding mooring lines. In some embodiments, first column 211, second column 212, and third column 213 may each be configured to connect to one corresponding mooring line, two corresponding mooring lines, three corresponding mooring lines, or more. In other embodiments, first pontoon 214, second pontoon 215, and third pontoon 216 may each be configured to connect to one corresponding mooring line, two corresponding mooring lines, three corresponding mooring lines, or more. The vertically positioned mooring system 220 may be configured to maintain the hull structure 210 within specified tolerances in a lateral direction, i.e., in a surge direction and / or a sway direction and / or a yaw direction, when the offshore floating platform system 200 is subjected to meteorological and oceanographic conditions.

[0029] In some embodiments, vertically disposed mooring system 220 may include first anchor 221, second anchor 222, and third anchor 223. In some embodiments, first anchor 221, second anchor 222, and third anchor 223 may each be a suction pile, a driven pile, a gravity anchor, or a combination thereof. In some embodiments, first anchor 221, second anchor 222, and third anchor 223 may each be configured to be secured to seabed 205 and may be configured to connect to or receive one or more mooring lines. In other embodiments, first anchor 221, second anchor 222, and third anchor 223 may each be configured to connect to or receive two mooring lines, three mooring lines, or more. In some embodiments, first anchor 221, second anchor 222, and third anchor 223 may each be designed to transfer a lift force or a lateral force, or a combination thereof, from a corresponding mooring line 231, 232, 233 to the seabed 205. The particular configuration of anchors 221, 222, 223 may be based at least in part on the type of seabed 205 at the site, e.g., soil conditions, and the loads expected to be exerted on anchors 221, 222, 223 when connected to hull structure 210 via mooring lines.

[0030] In some embodiments, vertically disposed mooring system 220 may include first mooring line 231, second mooring line 232, and third mooring line 233. In some embodiments, first mooring line 231 may be configured to be connected to first column 211 at a first end of first mooring line 231 and to first anchor 221 at a second end of first mooring line 231, second mooring line 232 may be configured to be connected to second column 212 at a first end of second mooring line 232 and to second anchor 222 at a second end of second mooring line 232, and third mooring line 233 may be configured to be connected to third column 213 at a first end of third mooring line 233 and to third anchor 223 at a second end of third mooring line 233.

[0031] In some embodiments, first mooring line 231, second mooring line 232, and third mooring line 233 can each be formed from a synthetic rope. In other embodiments, at least a portion of first mooring line 231, second mooring line 232, and third mooring line 233 can be formed from a synthetic rope, and at least a portion of first mooring line 231, second mooring line 232, and third mooring line 233 can be formed from wire rope and / or chain and / or other elongated members. In some embodiments, the synthetic rope can be formed from or otherwise include a synthetic polymer. In some embodiments, the synthetic polymer can be or include, without limitation, polyester, nylon, ultra-high molecular weight polyethylene (UHMWPE), or any combination thereof. In some embodiments, the synthetic polymer rope can be or include a synthetic polymer rope, such as DEEPROPE® polyester rope available from Bexco, or MOORLINE® polyester rope available from Bridon, or CABRAL 512® polyester rope available from Lankhorst, or DYNEEMA® UHMWPE rope available from DSM, or any other synthetic polymer rope having suitable properties.

[0032] In some embodiments, first mooring line 231, second mooring line 232, and third mooring line 233 may each be configured with a pre-tension such that first mooring line 231, second mooring line 232, and third mooring line 233 are always in tension when offshore floating platform system 200 is exposed to weather and ocean conditions and when hull structure 210 moves. In some embodiments, the pre-tension may be selected to avoid snap or shock loads on first mooring line 231, second mooring line 232, and / or third mooring line 233. In some embodiments, the pre-tension may be about 50 tons, about 100 tons, about 150 tons, about 200 tons, about 225 tons, about 250 tons, about 300 tons, about 350 tons, or about 400 to about 450 tons, about 500 tons, about 550 tons, or more. In some embodiments, the pretension can be from about 225 tons to about 300 tons, from about 300 tons to about 450 tons, or from about 450 tons to about 550 tons or more. The selection of the pretension for first mooring line 231, second mooring line 232, and third mooring line 233 can be based at least in part on the expected weather and ocean conditions at the site, the water depth, the characteristics of mooring lines 231, 232, 233, the dimensions of hull structure 210, or any combination thereof.

[0033] In some embodiments, first anchor 221, second anchor 222, and third anchor 223 may be positioned on or secured to seabed 205 such that first mooring line 231, second mooring line 232, and third mooring line 233 may each be oriented perpendicular or substantially perpendicular to the ground. Thus, first mooring line 231, second mooring line 232, and third mooring line 233 may be oriented within 0.5 degrees, 1 degree, 3 degrees, 5 degrees, 7 degrees, 9 degrees, 11 degrees, 13 degrees, 15 degrees, 17 degrees, or 20 degrees of an axis that is perpendicular to the ground.

[0034] In some embodiments, the vertically positioned mooring system 220 may be configured such that when the offshore floating platform system 200 is subjected to meteorological and oceanographic conditions, and when the hull structure 210 of the offshore floating platform system 200 moves laterally, i.e., in a surge direction and / or a sway direction and / or a yaw direction, the mean tension or average tension of the first mooring line 231, the second mooring line 232, and the third mooring line 233 may remain substantially equivalent to one another. The term "substantially equivalent" with respect to average tension or mean tension means that when the hull structure 210 moves laterally, the average tension or mean tension of the first mooring line 231, the average tension or mean tension of the second mooring line 232, and the average tension or mean tension of the third mooring line 233 are all within 20% of each other, within 15% of each other, within 10% of each other, or within 5% of each other.

[0035] In some embodiments, vertically disposed mooring system 220 can further include fourth mooring line 234, fifth mooring line 235, and sixth mooring line 236. Fourth mooring line 234 can be connected to first column 211 at a first end thereof and to first anchor 221 at a second end thereof, fifth mooring line 235 can be connected to second column 212 at a first end thereof and to second anchor 222 at a second end thereof, and sixth mooring line 236 can be connected to third column 213 at a first end thereof and to third anchor 223 at a second end thereof. In some embodiments, fourth mooring line 234, fifth mooring line 235, and sixth mooring line 236 may each be formed from synthetic rope. In other embodiments, at least a portion of fourth mooring line 234, fifth mooring line 235, and / or sixth mooring line 236 may be formed from synthetic rope, and at least a portion of first mooring line 234, second mooring line 235, and / or third mooring line 236 may be formed from wire rope and / or chain and / or other elongated members.

[0036] In some embodiments, the synthetic rope can be formed from or otherwise include a synthetic polymer. In some embodiments, the synthetic polymer can be or include, without limitation, polyester, nylon, ultra-high molecular weight polyethylene (UHMWPE), or any combination thereof. In some embodiments, the synthetic polymer rope can be or include a synthetic polymer rope, such as DEEPROPE® polyester rope available from Bexco, MOORLINE® polyester rope available from Bridon, CABRAL 512® polyester rope available from Lankhorst, DYNEEMA® UHMWPE rope available from DSM, or any other synthetic polymer rope having suitable properties.

[0037] In some embodiments, fourth mooring line 234, fifth mooring line 235, and sixth mooring line 236 may each be configured with a pre-tension such that fourth mooring line 234, fifth mooring line 235, and sixth mooring line 236 are always in tension when system 200 is exposed to weather and sea conditions and when hull structure 210 moves. In some embodiments, the pre-tension may be selected to avoid snap or shock loads on fourth mooring line 234, fifth mooring line 235, and / or sixth mooring line 236. In some embodiments, the pre-tension may be about 50 tons, about 100 tons, about 150 tons, about 200 tons, about 225 tons, about 250 tons, about 300 tons, about 350 tons, or about 400 to about 450 tons, about 500 tons, about 550 tons, or more. In some embodiments, the pretension can be from about 225 tons to about 300 tons, from about 300 tons to about 450 tons, or from about 450 tons to about 550 tons or more. The selection of the pretension for the fourth mooring line 234, the fifth mooring line 235, and the sixth mooring line 236 can be based at least in part on the expected weather and ocean conditions at the site, the water depth, the characteristics of the mooring lines 234, 235, 236, the dimensions of the hull structure 210, or any combination thereof.

[0038] In some embodiments, the vertically positioned mooring system 220 may include a fourth anchor 224, a fifth anchor 225, and a sixth anchor 226, to which a fourth mooring line 234, a fifth mooring line 235, and a sixth mooring line 236, respectively, may be connected, as shown. In such an embodiment, the fourth mooring line 234 may be connected to the first column 211 at a first end of the fourth mooring line 234 and connected to the fourth anchor 224 at a second end of the fourth mooring line 234, the fifth mooring line 235 may be connected to the second column 212 at a first end of the fifth mooring line 235 and connected to the fifth anchor 225 at a second end of the fifth mooring line 235, and the sixth mooring line 236 may be connected to the third column 213 at a first end of the sixth mooring line 236 and connected to the sixth anchor 226 at a second end of the sixth mooring line 236. In other embodiments, the fourth mooring line 234, the fifth mooring line 235, and the sixth mooring line 236 may be connected to the hull structure 210 at first ends of the mooring lines and connected to the first anchor 221, the second anchor 222, and the third anchor 223, respectively (not shown).

[0039] In some embodiments, the fourth anchor 224, the fifth anchor 225, and the sixth anchor 226 may each be designed to transfer lift forces, lateral forces, or a combination thereof from the corresponding mooring lines 234, 235, 236 to the seabed 205. In some embodiments, the fourth anchor 224, the fifth anchor 225, and the sixth anchor 226 may each be configured as a suction pile, a driven pile, or a gravity anchor. The particular configuration of the anchors 224, 225, 226 may be based at least in part on the type of seabed 205 at the site, e.g., soil conditions, and the loads expected to be exerted on the anchors 224, 225, 226 when connected to the hull structure 210 via the mooring lines.

[0040] In some embodiments, fourth anchor 224, fifth anchor 225, and sixth anchor 226 may be positioned such that fourth mooring line 234, fifth mooring line 235, and sixth mooring line 236 may each be oriented vertically or substantially vertically relative to the ground. In other embodiments, fourth anchor 224, fifth anchor 225, and sixth anchor 226 may be positioned on or secured to seabed 205 such that fourth mooring line 234, fifth mooring line 235, and sixth mooring line may each be substantially vertical.

[0041] In some embodiments, the vertically positioned mooring system 220 may be configured such that when the offshore floating platform system 200 is subjected to meteorological and oceanographic conditions, and when the hull structure 210 of the offshore floating platform system 200 moves laterally or in a surge or sway direction, the average tension or mean tension of the first mooring line 231, the average tension or mean tension of the second mooring line 232, the average tension or mean tension of the third mooring line 233, and, if present, the average tension or mean tension of the fourth mooring line 234, the average tension or mean tension of the fifth mooring line 235, and / or the average tension or mean tension of the sixth mooring line 236 may remain substantially equivalent to one another. In some embodiments, substantially equivalent to each other means that when the hull structure 210 moves laterally or in a surge or sway direction, the average tension or mean tension of the first mooring line 231, the average tension or mean tension of the second mooring line 232, the average tension or mean tension of the third mooring line 233, and, if present, the average tension or mean tension of the fourth mooring line 234, the average tension or mean tension of the fifth mooring line 235, and / or the sixth mooring line 236 are all within 20% of each other, or all within 15% of each other, or all within 10% of each other, or all within 5% of each other.

[0042] It should be appreciated that in some embodiments, mooring system 220 may include three anchors and three mooring lines, with each mooring line configured to connect to hull structure 210 and a corresponding anchor. In other words, in some embodiments, vertically disposed mooring system 220 may include first anchor 221, second anchor 222, and third anchor 223, and first mooring line 231, second mooring line 232, and third mooring line 233.

[0043] In some embodiments, the vertical distance between the surface 203 of the body of water 201 and the ocean floor 205 may be referred to as the water depth. In some embodiments, the water depth may be about 100 meters, about 200 meters, about 300 meters, about 400 meters, or about 500 meters to about 600 meters, about 700 meters, about 800 meters, about 900 meters, about 1,000 meters, about 1,200 meters, about 1,400 meters, or more. In some embodiments, the water depth may be about 200 meters to about 300 meters, about 300 meters to about 500 meters, or about 500 meters to about 1,000 meters, or more than 1,000 meters.

[0044] Hypothetical examples were conducted through computer simulations of two offshore floating platform systems, each including a hull structure moored to the seabed via a vertically positioned mooring system. The hull structure includes three columns and three pontoons connecting the columns to each other in a triangular configuration. The vertically positioned mooring system includes six mooring lines for mooring the hull structure to the seabed. Each mooring line includes a 190 mm diameter polyester rope with a minimum breaking load of 1,208 tons. Each mooring line includes a short length of chain (approximately 20 meters) positioned between the corresponding anchor and the polyester rope. The first end of each mooring line is secured to the corresponding column via a corresponding unijoint. The second end of each mooring line, i.e., the short length of chain, is connected to the corresponding anchor via a unijoint. A pretension of 400 tons is applied to each mooring line. The water depth is 1,000 meters. In the first hypothetical example, the hull structure is configured with the following parameters, as shown in the table below: [Table 1]

[0045] 5 graphically illustrates an exemplary set of curves for a hull structure moored to the seabed when constructed according to the above table, including a response amplitude operator (RAO) 510 in the heave direction of an offshore floating platform system, a RAO 520 in the pitch and / or roll direction of the offshore floating platform system, and a wave spectrum 530 on the surface of the body of water, according to one or more embodiments. The wave spectrum 530 on the surface of the body of water may have a peak spectral period 531. The RAO 510 in the heave direction of the offshore floating platform system may have a peak response period 511 and a cancellation period 512. The RAO 520 in the pitch and / or roll direction of the offshore floating platform system may have a peak response period 521. In some examples, the peak response period 511 in the heave direction of the offshore floating platform system may be less than the peak spectral period 531 of the wave spectrum 530, and the peak response period 521 in the pitch and / or roll direction of the offshore floating platform system may be greater than the peak spectral period 531 of the wave spectrum 530 on the surface of the body of water.

[0046] In some embodiments, the dimensions of the hull structure, the mass properties of the hull structure, e.g., mass and radius of rotation, the axial stiffness of the mooring line(s), and / or the pretensioning of the vertical mooring system may be selected such that movement of the offshore floating platform system in the heave direction and in the pitch and / or roll directions may reduce or eliminate resonance in the heave direction and / or resonance in the pitch and / or roll directions.

[0047] In some embodiments, the cancellation period 512 can be substantially similar to the peak spectral period 531. In some embodiments, substantially similar, when comparing the cancellation period 512 to the peak spectral period 531, means that the cancellation period 512 can be within + / - 2.5 seconds, + / - 2 seconds, + / - 1.5 seconds, + / - 1 second, + / - 0.5 seconds, or 0.25 seconds of the peak spectral period 531. In some embodiments, the dimensions of the hull structure (including the dimensions of the first column, second column, third column, first pontoon, second pontoon, and third pontoon) can be selected such that the cancellation period 512 is substantially similar to the peak spectral period 531. In some embodiments, the dimensions of the hull structure, the axial stiffness of the mooring line(s), and / or the pretension of the vertical mooring system can be selected such that the cancellation period 512 is substantially similar to the peak spectral period 531 of the floating offshore platform system.

[0048] 5, in some embodiments, the RAO 510 in the heave direction of the offshore floating platform system may have a peak response period 511 of about 12 seconds and a cancellation period 512 of about 14 seconds, and the peak spectral period 531 of the wave spectrum 530 on the surface of the body of water may be about 14 seconds. In some embodiments, the peak response period 521 of the RAO 520 in the pitch and / or roll direction of the offshore floating platform system may be about 21 seconds, and the peak spectral period 531 of the wave spectrum 530 on the surface of the body of water may be about 14 seconds.

[0049] In some embodiments, an offshore floating platform system may be configured to support equipment, such as an offshore wind turbine, on a hull structure. In such embodiments, the dimensions of the hull structure, the mass properties of the hull structure, such as mass and radius of rotation, the axial stiffness of the mooring lines, and / or the pretension of the mooring lines in the vertical mooring system may be selected to ensure that motions of the offshore floating platform comply with allowable design parameters for the equipment.

[0050] FIG. 6 diagrammatically illustrates an exemplary set of curves in a second hypothetical example for another offshore floating platform system including a different hull structure moored to the seabed via a vertical mooring system, including RAO 610 in the heave direction of the offshore floating platform system, RAO 620 in the pitch and / or roll direction of the offshore floating platform system, and a wave spectrum 630 on the surface of the body of water, according to one or more embodiments. The hull structure includes three columns and three pontoons connecting the columns to each other in a triangular configuration, but the parameters of the hull structure are different from those in the first hypothetical example. The vertical mooring system is the same as the vertical mooring system in the first hypothetical example. The wave spectrum 630 on the surface of the body of water may have a peak spectral period 631. The RAO 610 of the offshore floating platform system in the heave direction may have a peak response period 611 and a cancellation period 612. The RAO 620 of the offshore floating platform system in the pitch and / or roll directions may have a peak response period 621. In some embodiments, the peak response period 611 of the offshore floating system in the heave direction and the peak response period 621 of the offshore floating system in the pitch and / or roll directions may each be greater than the peak spectral period 631 of the wave spectrum 630 on the surface of the body of water.

[0051] In some examples, the RAO 610 in the heave direction of the offshore floating platform system may have a peak response period 611 of about 18 seconds, and the peak spectral period 631 of the wave spectrum 630 may be about 14 seconds. In some examples, the cancellation period 612 may be greater than the peak spectral period 631 of the wave spectrum 630. In some examples, the dimensions of the hull structure (including the dimensions of the first column, the second column, the third column, the first pontoon, the second pontoon, and the third pontoon), the axial stiffness of the mooring lines, and / or the pretension of the vertically positioned mooring system may be selected such that the cancellation period 612 is greater than the peak spectral period 631 of the wave spectrum 630 on the surface of the body of water. In some examples, the dimensions of the hull structure, the axial stiffness of the mooring lines, and / or the pretensioning of the vertical mooring system may be selected such that the cancellation period 612 and the peak response period 611 in the heave direction may be greater than the peak spectral period 631 of the wave spectrum 630 on the surface of the body of water. In some examples, the RAO 620 in the pitch or roll direction of the offshore floating platform system may have a peak response period 621 of about 24 seconds, and the peak spectral period 631 of the wave spectrum 630 on the surface of the body of water may be about 14 seconds.

[0052] In some examples, the dimensions of the hull structure, the mass properties of the hull structure, e.g., mass and radius of rotation, the axial stiffness of the mooring lines, and / or the pretension of the vertical mooring system may be selected such that motion of the offshore floating platform system in the heave direction and / or in the pitch direction and / or in the roll direction may be such that heave resonance, pitch resonance, and / or roll resonance may be reduced or eliminated. In some examples, the offshore floating platform system may be configured to support equipment, e.g., an offshore wind turbine, on the hull structure. In such examples, the dimensions of the hull structure, the mass properties of the hull structure, the axial stiffness of the mooring lines, and / or the pretension of the mooring lines in the vertical mooring system may be selected such that motion of the offshore floating platform conforms to the allowable design parameters of the equipment.

[0053] 7 shows an isometric view of an exemplary offshore floating platform system 200 similar to that shown in FIGS. 2-4, including an optional wind turbine generator system 710 disposed on the hull structure 210. In addition to the wind turbine generator system 710, a vertical mooring system 220 is included, where instead of both mooring lines being connected to separate anchors, two mooring legs connected to each column are connected to corresponding anchors 221, 222, or 223. The wind turbine generator system 710 may include a mast 720 mounted or otherwise disposed on the hull structure 210, which may be configured to support a wind turbine generator 730. The wind turbine generator system 710 may also include a plurality of blades 740, three shown in the figure, that rotate the generator in response to incoming or oncoming wind to generate electricity.

[0054] Some examples and features have been described using a set of upper numerical limits and a set of lower numerical limits. It should be appreciated that ranges including combinations of any two values ​​are contemplated, for example, any lower value with any upper value, any two lower values, and / or any two upper values, unless otherwise indicated. Some lower limits, upper limits, and ranges are set forth in one or more claims below. All numerical values ​​are "about" or "approximately" stated values ​​and take into account experimental error and variations that would be expected by one of ordinary skill in the art.

[0055] Various terms have been defined above. Unless a term used in the claims may not be defined above, that term should be given the broadest definition that one of ordinary skill in the art has given that term, as reflected in at least one printed publication or issued patent. Furthermore, all patents, test procedures, and other literature cited in this application are incorporated by reference in their entirety to the extent such disclosures are not inconsistent with this application and for all jurisdictions where such incorporation may be permitted.

[0056] While certain preferred embodiments of the present invention have been shown and described in detail above, it will be apparent that modifications and adaptations thereof will occur to those skilled in the art. It is therefore to be expressly understood that such modifications and adaptations can be devised without departing from the basic scope thereof, which scope is to be determined by the following claims.

Claims

1. 1. An offshore floating platform system, comprising: a hull structure configured to float on the surface of a body of water; an anchor configured to be secured to the seabed; a mooring line configured to be connected to the hull structure at a first end of the mooring line and to the anchor at a second end of the mooring line; Equipped with when the anchors are secured to the seabed and the mooring lines are connected to the hull structure and the anchors, the mooring lines are substantially vertical and a peak response period of the offshore floating platform system in a pitch or roll direction is greater than a peak spectral period of a wave spectrum on the surface of the body of water; Offshore floating platform system.

2. The system of claim 1 , wherein a cancellation period of the offshore floating platform system in a heave direction is substantially equal to the peak spectral period of the wave spectrum on the surface of the body of water.

3. 3. The system of claim 1 or 2, wherein a peak response period of the offshore floating platform system in a heave direction is less than the peak spectral period of the wave spectrum on the surface of the body of water.

4. 3. The system of claim 1 or 2, wherein a peak response period of the offshore floating platform system in a heave direction is greater than the peak spectral period of the wave spectrum on the surface of the body of water.

5. 5. The system of claim 1, wherein the peak response period of the offshore floating platform system in the pitch direction and in the roll direction is greater than the peak spectral period of the wave spectrum on the surface of the body of water.

6. 6. The system of claim 1, wherein the offshore floating platform system further comprises a wind turbine generator system supported by the hull structure, and wherein the mass of the hull structure, the shape of the hull structure, and the axial stiffness of the mooring lines are selected to accommodate movement of the offshore floating platform system in the heave, roll, and pitch directions for a wind turbine generator.

7. 7. The system of claim 1, wherein the depth of the body of water is greater than 200 meters.

8. the anchor is a first anchor, the mooring line is a first mooring line, the hull structure comprises a first column, a second column, and a third column, and the system comprises: a second anchor configured to be secured to the seabed; and a third anchor configured to be secured to the seabed; and a second mooring line; and a third mooring line; Furthermore, the first mooring line is configured to be connected to the first column at a first end of the first mooring line and to be connected to the first anchor at a second end of the first mooring line; the second mooring line is configured to be connected to the second column at a first end of the second mooring line and to be connected to the second anchor at a second end of the second mooring line; the third mooring line is configured to be connected to the third column at a first end of the third mooring line and to be connected to the third anchor at a second end of the third mooring line; when the first anchor, the second anchor, and the third anchor are fixed to the seabed and the first mooring line, the second mooring line, and the third mooring line are connected to the first column, the second column, and the third column, and the first anchor, the second anchor, and the third anchor, respectively, the first mooring line, the second mooring line, and the third mooring line are each substantially vertical; A system according to any one of claims 1 to 7.

9. 9. The system of claim 8, wherein the first column, the second column, and the third column are configured in a triangular arrangement relative to one another when viewed in plan, and the first column, the second column, and the third column are connected to one another via a structural frame.

10. 10. The system of claim 8 or 9, wherein the first mooring line, the second mooring line, and the third mooring line are each formed from a synthetic rope and, optionally, segments of wire rope and / or segments of chain.

11. 11. The system of claim 10, wherein the synthetic rope is a polyester rope and the first mooring line, the second mooring line, and the third mooring line are each oriented within 20 degrees of an axis that is perpendicular to the ground.

12. 12. The system of claim 11, wherein the average tension or tensions in the first mooring line, the second mooring line, and the third mooring line all remain substantially equivalent to one another when the hull structure moves laterally, surges, or sways.

13. a fourth mooring line; and a fifth mooring line; and The sixth mooring line and Furthermore, the fourth mooring line is configured to be connected to the first column at a first end of the fourth mooring line and to be connected to the first anchor at a second end of the fourth mooring line; the fifth mooring line is configured to be connected to the second column at a first end of the fifth mooring line and to be connected to the second anchor at a second end of the fifth mooring line; the sixth mooring line is configured to be connected to the third column at a first end of the sixth mooring line and to be connected to the third anchor at a second end of the sixth mooring line; when the first anchor, the second anchor, and the third anchor are fixed to the seabed and the fourth mooring line, the fifth mooring line, and the sixth mooring line are connected to the first column, the second column, and the third column, and the first anchor, the second anchor, and the third anchor, respectively, the first mooring line, the second mooring line, the third mooring line, the fourth mooring line, the fifth mooring line, and the sixth mooring line are each substantially vertical; A system according to any one of claims 8 to 12.

14. a fourth mooring line; and a fifth mooring line; and a sixth mooring line; and a fourth anchor configured to be secured to the seabed; and a fifth anchor configured to be secured to the seabed; and a sixth anchor configured to be secured to the seabed; and Furthermore, the fourth mooring line is configured to be connected to the first column at a first end of the fourth mooring line and to be connected to the fourth anchor at a second end of the fourth mooring line; the fifth mooring line is configured to be connected to the second column at a first end of the fifth mooring line and to be connected to the fifth anchor at a second end of the fifth mooring line; the sixth mooring line is configured to be connected to the third column at a first end of the sixth mooring line and to be connected to the sixth anchor at a second end of the sixth mooring line; when the fourth mooring line is connected to the first column and the fourth anchor, the fifth mooring line is connected to the second column and the fifth anchor, and the sixth mooring line is connected to the third column and the sixth anchor, the fourth mooring line, the fifth mooring line, and the sixth mooring line are each substantially vertical; A system according to any one of claims 8 to 12.

15. 15. The system of claim 13 or 14, wherein the fourth mooring line, the fifth mooring line, and the sixth mooring line are each formed from a synthetic rope and, optionally, segments of wire rope and / or segments of chain.

16. 16. The system of claim 15, wherein the synthetic rope is a polyester rope and the first mooring line, the second mooring line, the third mooring line, the fourth mooring line, the fifth mooring line, and the sixth mooring line are each oriented to be within about 20 degrees of an axis that is perpendicular to the ground.

17. 17. A system as claimed in any one of claims 13 to 16, wherein the average tension or tensions in the fourth mooring line, the fifth mooring line and the sixth mooring line all remain substantially equivalent to one another when the hull structure moves laterally, surge or sway.

18. 1. A process for mooring an offshore platform, comprising: providing an offshore floating platform system comprising a hull structure configured to float on the surface of a body of water, an anchor configured to be secured to a seabed, and a mooring line configured to connect to the hull structure and the anchor; securing the anchor to the seabed; connecting a first end of the mooring line to the hull structure and a second end of the mooring line to the anchor; Including, when the anchors are secured to the seabed and the mooring lines are connected to the hull structure and the anchors, the mooring lines are substantially vertical and a peak response period of the offshore floating platform system in a pitch or roll direction is greater than a peak spectral period of a wave spectrum on the surface of the body of water; process.

19. 20. The process of claim 18, wherein a peak response period of the offshore floating platform system in a heave direction is less than the peak spectral period of the wave spectrum on the surface of the body of water.

20. 20. The process of claim 18 or 19, wherein the cancellation period of the offshore floating platform system is substantially similar to the peak spectral period of the wave spectrum on the surface of the body of water.

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