Ocean platforms with tuned mass dampers and hydraulic dampers

Abstract

Techniques are disclosed herein for minimizing movement of an offshore marine platform. Using the technologies described, a payload may be mounted on a marine platform that is constructed and deployed to reduce the motions of the platform due to wind, wave, and other environmental factors on the platform in both shallow and deep waters. In some configurations, a fully restrained platform (FRP) including a monopile with integrated tuned mass dampers is configured to reduce the environmental load.

Description

OCEAN PLATFORMS WITH TUNED MASS DAMPERS AND HYDRAULIC DAMPERSBACKGROUND

[0001] Deep-water regions off coastlines offer tremendous potential as wind power resources. Marine structures, commonly termed as platforms, may be used for hosting wind turbines, extracting oil and gases, and providing various offshore work areas. Determining how to reduce movement of the marine platform, however, can be challenging. In an open ocean, winds, waves, and currents often act simultaneously and exert forces on the marine platforms causing the platforms to move.BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1 illustrates a fixed ocean platform that incorporates a wind turbine and one or more tuned mass dampers according to some implementation.

[0003] FIG. 2 illustrates a fixed ocean platform that incorporates one or more tuned mass dampers and has a top structure for supporting additional payloads according to some implementation.

[0004] FIG. 3 illustrates another fixed ocean platform that incorporates one or more tuned mass dampers and has a top structure for supporting additional payloads according to some implementation.

[0005] FIG. 4 illustrates another fixed ocean platform that incorporates one or more tuned mass dampers and one or more hydraulic dampers for restraining the fixed ocean platform against environmental loads according to some implementation.

[0006] FIG. 5 illustrates another fixed ocean platform that incorporates one or more tuned mass dampers and a moonpool according to some implementation.1Aty Docket No.: E123-0006PCT

[0007] FIG. 6 illustrates another fixed ocean platform that incorporates one or more tuned mass dampers with integrated pumping and sensing systems according to some implementation.

[0008] FIG. 7 illustrates another fixed ocean platform that incorporates one or more retrofitted or external tuned mass dampers for restraining the fixed ocean platform against environmental loads according to some implementation.

[0009] FIG. 8 illustrates a top view of a tuned mass damper for use with a fixed ocean platform according to some implementation.

[0010] FIG. 9 illustrates a cross-sectional view of a tuned mass damper for use with a fixed ocean platform according to some implementation.

[0011] FIG. 10 illustrates an example hydraulic damper for use with a mooring line of a fixed ocean platform according to some implementation.

[0012] FIG. 11 further illustrates in diagram a relationship between the natural frequencies of exemplary FRP -monopiles implemented as described herein and wave frequencies.DETAILED DESCRIPTION

[0013] The following detailed description is directed to technologies for minimizing movement of offshore platforms, such as those that host wind turbines, oil and gas extraction sites, as well as other payloads for various functions. For example, using the technologies described herein, a wind turbine, oil and gas extraction equipment, and / or other payloads may be mounted on a marine platform that is constructed and deployed to reduce movements and / or environmental loads (e.g., wind, waves, and the like) on the platform in both shallow water (e.g., less than 120 meters) and deep water (e.g., greater than 40 meters). According used herein, the terms fully restrained platform (FRP) refers to a platform that has motions restrained in 6 degrees-2Aty Docket No.: E123-0006PCTof-freedom (DOFs), FRP-monopile refers to a platform that includes a monopile, FRP-moonpool refers to a platform that includes a hollow monopile (e.g., for use in oil and gas extraction), and the term FRP-monohull refers to a platform that includes a buoyant structure.

[0014] For purposes of explanation, the main structural component of a platform can be viewed as a rigid body. Its motions are characterized by and measured in 6 degrees-of-freedom (DOFs) including three translational (surge, sway and heave), and three rotational (roll, pitch, and yaw). The environmental loads can force the platform to move in one or more DOFs. Some of these loads are dynamic in nature such as those from the water waves, others are mainly steady such as the ocean current induced drag.

[0015] The platforms including the FRPs discussed herein, are configured to utilize tuned mass dampers (TMD), tuned liquid dampers (TLD), and / or hydraulic dampers (HD) to reduce vibrations of such an ocean platform and enhance the platforms strength, particularly in deeper waters. One type of TMD (or TLD), discussed herein, is a sloshing liquid tank. The sloshing liquid tank is a device that utilizes a sloshing motion associated with a liquid to reduce vibrations in the corresponding structure. In some cases, the HDs, discussed herein, are damping elements (e.g., a pressure pipe filled with liquids such as oil, a piston system, an elastic element such as a spring, and / or the like) that convert kinetic energy of the moving parts into thermal energy. This avoids hard impacts or excessive vibration amplitudes. In some examples, the terms TMD and TLD are used interchangeably as TLD is a type of TMD.

[0016] In some implementations, the platforms may utilize one or more TLDs on the monopile along with one or more HDs for individual mooring lines. Accordingly, the TLDs and HDs discussed herein are used on the offshore platforms to reduce dynamic motions of the platform, alleviate dynamic forces in mooring lines, and / or3Aty Docket No.: E123-0006PCTextend the lifespan of such structures when compared with conventional platforms. In some examples, when equipped with TLDs and HDs, discussed here, the fixed platforms such as monopiles and FRPs may be used in deeper water, have enhanced motion performance, expanded payload-carrying capabilities, and extended lifespan when compared with conventional platforms. Additionally, the TLDs and HDs are particularly useful on platforms including large diameter column structures. For instance, in some examples, the columns may be partitioned to form one or more TLDs (e.g., liquid tanks, slush tanks, and / or the like) at no significant manufacturing and deployment costs.

[0017] In the following detailed description, references are made to the accompanying drawings that form a part hereof, and that show, by way of illustration, specific examples or examples. The drawings herein are not drawn to scale. Like numerals represent like elements throughout the several figures (which may be referred to herein as a “FIG.” or “FIGS ”).

[0018] FIG. 1 illustrates a fixed ocean platform 100 that incorporates a wind turbine 102 and one or more tuned mass dampers 104(A)-(C) according to some implementation. In the current example, the fixed ocean platform 100 may be a FRP that includes a monopile 106 embedded in the soil and below a mudline 108 of the ocean or sea floor to secure or restrain the platform 100 against environmental loads (e.g., wind, waves, and the like). In some cases, the monopile 106 is a large diameter circular column pile supporting a top structure or top side structure 110. In the current example, the top structure 110 is configured to support a wind turbine 102 for the generation of electricity. In other cases, the top structure 110 may support other payloads, such as oil and gas prospecting and / or extracting equipment, electoral4Aty Docket No.: E123-0006PCTsystems, weather or environmental condition tracking equipment, refueling equipment, a combination thereof, and / or the like.

[0019] In the current example, an upper portion of the column of the monopile 106 is partitioned into three TMDs 104(A)-(C). In the illustrated example, the TMDs 104 are in the form of liquid tanks being filled with a liquid (such as oil, water, or the like) to a predetermined level, indicated by 112(A)-(C) for each corresponding TMD 104(A)-(C). In various implementations, the predetermined fill level 112(A)-(C) may be determined based on conditions associated with the environment surrounding the platform 100. For example, the water depth, typical wind conditions, typical surf or wave conditions, and the like may be utilized to determine the predetermined fill level 112(A)-(C) for each of the each corresponding TMD 104(A)-(C). It should be understood that the predetermined fill level 112(A)-(C) may differ from each other or be the same. For example, the predetermined fill level 112(A) of TMD 104(A) may be lower than the predetermined fill level 112(C) of TMD 104(C).

[0020] It should also be understood that the liquid in each TMD 104(A)-(C) may be the same or differ from one tank to the next. For instance, the TMD 104(A) may be filled with water while the TMD 104(C) may be filled with oil. In some cases, the liquid may be selected based on a relative position of the TMD 104 within the monopile 106. In some cases, the size (e.g., volume, height, or width) of each TMD 104 may vary. For example, the TMD 104(B) may have a larger volume of liquid than the TMDs 104(A) or 104(C) (e.g., the TMD 104(B) is larger than the TMDs 104(A) and 104(C)) or the like.

[0021] As an illustrated example, the predetermined fill level 112(A)-(C) may be determined as follows noting that the ocean wave frequencies are typically in a range of 0.03 to 0.3 Hertz (Hz). In some situations, such as in a fatigue sea state, frequencies5Aty Docket No.: E123-0006PCTof the waves are in the upper half of the ocean wave frequency range but typically have smaller wave heights than are experienced in extreme weather. Conversely, the waves associated with the extreme weather may be in a lower half of the ocean wave frequencies range but at a larger wave height. For example, a fatigue wave could have a frequency of 0.167 Hz (also termed as a 6-second period wave). An extreme wave may have a frequency of 0.08 Hz (a 12.5 second wave). For a fixed platform, such as platform 100, consisting of large diameter (e.g., a monopile 106 having a diameter of between 5 meters and 13 meters) in a water depth of approximately 80 meters, the first natural frequency may decrease to a range of approximately 0.14 to 0.16 Hz and potentially cause resonance conditions to occur. In this situation, the TMD 104(A)-(C) of the illustrated example may be TLDs having a similar sloshing frequency (the TLDs fundamental natural frequency) to the wave excitation frequency. For a regular, circular-shaped liquid tank, the sloshing frequency and / or the height of the water / fluid in the tank may be determined by the Housner equation:Where, fcis the sloshing frequency in Hz, h is the height of the water in the tank in meters, D is the diameter of the circular tank in meters, and g is the acceleration due to gravity (m / s2).

[0022] For example, a circular tank of 10 meters (m) in diameter and a liquid level of 0.8m, the first natural frequency of sloshing is 0.16 Hz. When the tank is laterally excited, the maximum liquid height may also be estimated by an approximation as follows: the dynamic amplitude of the sloshing liquid is the lateral motion amplitude of the tank divided by the ratio of the static liquid level to the radius of the tank. For a lateral tank motion amplitude of 0.2m, the maximum (e.g., total) liquid height is6Aty Docket No.: E123-0006PCTapproximately 2.05m (the static liquid level 0.8 m plus the dynamic amplitude 1.25 m). In other examples, more sophisticated computer simulation or machine learning models may be utilized to account for variations in tank geometry and the like.

[0023] In some cases, the predetermined level 112(A)-(C) for each TMD 104 may be raised or lowered (such as dynamically or in substantially real-time based at least in part on environmental factors, such as water depth, wave height, wave frequency, and / or the like) to change the sloshing frequency. For example, the predetermined level of a TMD may be lowered to 0.4m for a 10m diameter tank to obtain a 0.08 Hz sloshing frequency to, thereby, reduce the motions of the platform 100 in an extreme wave conditions having a period of 12.5 seconds. Therefore, in various implementations, the TMDs 104 may operate under two types of settings for the liquid level 112. The first operational setting may be a default setting which is for day-to-day environment and includes a first predetermined liquid level and a second operational setting may be an event setting which involves targeting a current or upcoming environmental condition (such as an extreme storm) via a second predetermined level and / or a dynamic fluid level.

[0024] FIG. 2 illustrates a fixed ocean platform 200 that incorporates one or more tuned mass dampers 204(A)-(C) and has a top structure 202 for supporting additional payloads according to some implementation. In the current example, the fixed ocean platform 200 may be a FRP that includes a monopile 206 embedded in the soil and below a mudline 208 of the ocean or sea floor to secure or restrain the platform 200 against environmental loads (e.g., wind, waves, and the like). As discussed above, the monopile 206 is a large diameter circular column pile supporting the top structure 202. In the current example, the top structure 202 may support other payloads, such as turbines, oil and gas prospecting and / or extracting equipment, electrical systems,7Aty Docket No.: E123-0006PCTweather or environmental condition tracking equipment, refueling equipment, a combination thereof, and / or the like.

[0025] In the current example, an upper portion of the column of the monopile 206 is again partitioned into three TMDs 204(A)-(C). In the illustrated example, the TMDs 204 are in the form of liquid tanks being filled with a liquid (such as oil, water, or the like) to a predetermined level, indicated by 210(A)-(C) for each corresponding TMD 204(A)-(C). In various implementations, the predetermined fill level 210(A)-(C) may be determined based on conditions associated with the environment surrounding the platform 200. For example, the water depth, typical wind conditions, typical surf or wave conditions, and the like may be utilized to determine the predetermined fill level 210(A)-(C) for each of the each corresponding TMD 204(A)-(C). It should be understood that the predetermined fill level 210(A)-(C) may differ from each other or be the same. For example, as illustrated, the predetermined fill level 210(A) of TMD 104(A) may is higher than the predetermined fill level 210(B) of TMD 204(B) and the predetermined fill level 210(C) of TMD 204(C).

[0026] It should also be understood that the liquid in each TMD 204(A)-(C) may be the same or differ from one tank to the next. For instance, the TMD 204(A) may be filled with water while the TMD 204(C) may be filled with oil. In some cases, the liquid may be selected based on a relative position of the TMD 204 within the monopile 206. In some cases, the size (e.g., volume, height, or width) of each TMD 204 may vary. For example, the TMD 204(B) may have a larger volume of liquid than the TMDs 204(A) or 204(C) (e.g., the TMD 204(B) is larger than the TMDs 204(A) and 204(C)) or the like.

[0027] In some cases, a lower portion of the monopile 206 may be flooded such that the water level inside the lower portion of the monopile 206 matches or corresponds8Aty Docket No.: E123-0006PCTto the seawater level. In this manner, the water level in the lower portion of the monopile 206 may change with the daily tides.

[0028] FIG. 3 illustrates another fixed ocean platform 300 that incorporates one or more tuned mass dampers 304(A) and (B) and has a top structure 302 for supporting additional payloads according to some implementation. In the current example, in addition to the monopile 306 driven into the soil and below a mudline 308 of the ocean or seafloor, the platform 300 includes one or more mooring lines 310(A) and (B) to secure or restrain the platform 300 against environmental loads (e.g., wind, waves, and the like).

[0029] The mooring lines 310 may each be coupled to the platform 300 via a corresponding top mooring assembly (TMA) 312(A) and 312(B) and secured to the seafloor via one or more anchor piles 314(A) and 314(B). In some cases, the mooring lines 310 may be used to mitigate forces or motions applied to the monopile 306. In some implementations, each mooring line 310 may include a mooring line segment that is substantially above the waterline 316, a mooring line segment that is substantially below the waterline 316, and a connector that may connect the mooring line segments (approximately at or about the waterline 316 in some examples). The use of these mooring line segments and the connector may facilitate the ease of installation of the mooring lines 310. For example, the anchor piles 314 may be driven into or otherwise attached to the seafloor and the lower mooring line segment may be attached to the corresponding anchor pile 314. The lower mooring line segment may later be attached to the upper mooring line segment using the connector. For example, the monopile 306 and the anchor piles 314 may be installed on independent schedules and the mooring lines 310 and connected later.9Aty Docket No.: E123-0006PCT

[0030] The top mooring assemblies 312 may be mounted on or otherwise attached to the monopile 306. In various examples, the top mooring assemblies 312 may be mounted to the monopile 306 substantially above the waterline 316. The top mooring assemblies 312 may include a mooring porch affixed to the monopile 306 and that may directly bear the load applied by the mooring lines 310 tension. The porch may be welded or otherwise permanently and non-detachably affixed to the monopile 306. The top mooring assemblies 312 may further include a stopper to which the mooring line 310 may be connected. The mooring line 310 may connect to the stopper above the porch and pass through an opening in the porch, exiting below the porch. This opening may prevent the stopper from passing through the porch (e.g., may be smaller than the dimensions of the stopper). By connecting the mooring line 310 to the stopper, the stopper may be configured to prevent the mooring line 310 from moving below the porch. By applying a linear upwards force to the stopper 310 (e.g., “pulling” the stopper up), the tension in the mooring line 310 may be increased. Detailed examples of techniques and systems to perform this increase of tension are described herein.

[0031] The tension on the mooring line 310 (e.g., mooring line segments and connected via connector) may then be adjusted using the top mooring assemblies 312. In various examples, this tension may be increased or decreased after the initial mooring line 310 installation by manipulation of the stopper. The tension may then later be similarly adjusted as needed (e.g., using the top mooring assemblies 312 and, specifically, by manipulating the stopper) to maintain tension on the mooring line 340 within a desired or designed tension range. For example, a load cell may be configured at a point along the mooring line 310 (e.g., as or as connector) and / or where the mooring line 310 attaches to the stopper. This load cell may provide periodic, on-demand, and / or continuous tension monitoring to an operator who may then implement maintenance10Aty Docket No.: E123-0006PCTadjustments to the tension on the mooring line 310 by manipulating the top mooring assemblies 312 as described herein.

[0032] In some cases, the anchor piles 314 may be driven vertically or at an angle of batter (e.g., up to 45 degrees from vertical) into the seafloor. In some cases, discussed herein, the angular mooring lines 310 may be coupled to the monopile 306 at a departure angle (e.g., between zero and 45 degrees and corresponding to the angle of batter of the coupled pile 314). In some examples, the departure angle may be substantially equivalent (within a threshold of degrees) of the angle of batter of the driven anchor pile 314 to provide support for and transfer of axial loads to the seafloor. In some cases, the stiffness of a driven anchor pile 314 derives from both the surrounding soil of the seabed and the anchor pile structure itself. In some examples, each anchor pile 314 may be formed from multiple anchor piles driven at the same angle or at differing angles into the seafloor. For example, each anchor 314 may be formed via three piles driven into the seafloor and secured to the corresponding mooring line 310.

[0033] In some cases, the mooring lines 310 may be pretensioned mooring lines or dynamically tensioned mooring lines via the top mooring assembly 312 based on environmental conditions surrounding the platform 300. For example, the tension on the mooring lines 310 may be adjusted along with the water line and / or height or volume of liquid 318 within each of the TMDs 304, as discussed herein.

[0034] In some cases, the platform 300 may be installed into the seafloor by first driving or securing the anchor piles 314 into the seafloor at or below the mudline 308. The mooring lines 310 may then be coupled to the corresponding anchor piles 314 (such as the lower segment of the mooring lines when segments and connectors are utilized). The monopile 306 may then be transported (such as via a barge to the installation locations) and may be driven into the seafloor to a desired depth below the mudline11Aty Docket No.: E123-0006PCT308. In this example, the TMDs 304 may then be mounted to the monopile 306, such as on top surface of the monopile 306 when not integral to the monopile 306 (e.g., formed as an integral portion of the monopile 306). The mooring lines 310 may then be secured to the monopile 306 via a top mooring assembly 312. The mooring lines 310 may then be tensioned between the anchor pile 314 and the top mooring assembly 312 and / or the monopile 306.

[0035] Once the monopile 306 is secured and the mooring lines are tensioned, the top structure 302 may be mounted and the corresponding payload installed above the water. After the top structure 302 is secured to the monopile 306, the mooring lines 310 may again be tensioned or re-tensioned, such as using the top morning assemblies 312. The TMDs 304 may then be filled with liquid (e.g., oil, water, or another fluid) to the predetermined levels 318 for each individual tank or TMD 304.

[0036] FIG. 4 illustrates another fixed ocean platform 400 that incorporates one or more tuned mass dampers 404(A)-(C) and one or more hydraulic dampers 420(A) and (B) for restraining the fixed ocean platform 400 against environmental loads according to some implementation. As discussed above, the fixed ocean platform 400 may includes a monopile 406 having a top structure 402 above the waterline 416 for supporting various payloads, such as wind turbines, oil and gas prospecting and extraction equipment, weather monitoring systems, refueling equipment, and / or the like.

[0037] In the current example, the TMDs 404 are positioned below the waterline 416. Accordingly, it should be understood that the TMDs 404 may be placed at various heights or locations with respect to the depth of the water and the length of the monopile 306, such as above, at, or below the water line 416.12Aty Docket No.: E123-0006PCT

[0038] In some implementations, the monopile 406 and platform 402 may be secured via one or more mooring lines 410, top mooring assemblies 412, and / or anchor piles 414, in the current example and as discussed above. In the current example, each mooring line 410(A) and 410(B) may have a corresponding hydraulic dampers 420(A) and 420(B). In some cases, the hydraulic dampers 420 may include a cylinder coupled to, for instance, a lower segment of the mooring line and a piston coupled to an upper segment of the morning line (or vice versa - e.g., the cylinder coupled to the upper segment of the mooring line and the piston coupled to the lower segment of the morning line). In various implementation, the hydraulic dampers 420 may contract (e.g., compress) and expand (e.g., decompress) as the environmental load acts on the platform 400. For example, the piston may be pushed into the cylinder as an environmental load acts on the platform 400 and then the piston may rebound or spring out of the cylinder as the environmental load on the platform 400 dissipates. In various cases, the cylinder may be filled with different fluids (e.g., water, oil, or other fluid) having a desired viscosity to provide a desired damping effect on the environmental load.

[0039] In the current example, each mooring line 410 has a single corresponding hydraulic damper 420, however, it should be understood that each mooring line 410 may include multiple (e.g., two or more) hydraulic dampers 420. It should also be understood that the hydraulic dampers 420 may be positioned at various locations along the mooring lines 410, such as above the waterline 416, at the water line 416, and / or below the water line 416 (such as proximate to the anchor piles 414).

[0040] FIG. 5 illustrates another fixed ocean platform 500 that incorporates one or more tuned mass dampers 504, as discussed herein, and a moonpool 522 according to some implementation. As discussed above, the fixed ocean platform 500 may include13Aty Docket No.: E123-0006PCTa monopile 506 having a top structure 502 above the waterline 516 for supporting various payloads, such as wind turbines, oil and gas prospecting and extraction equipment (e.g., equipment 524, such as transformers, junction boxes, wellheads, controls, power sources, pumps, and the like, as shown in the illustrated example), weather monitoring systems, refueling equipment, and / or the like.

[0041] In the current example, the moonpool 522 is shown with oil and gas extracting pipes and segments 526 installed and extended below the mudline 508 into, for instance, a reservoir beneath the seafloor. In the current example, the moonpool 522 may be a hollow tube like opening for allowing equipment, such as the pipes and segments 526 to be lowered from the top structure 502 down below the mudline 508 of the seafloor. In some cases, the monopile 506 and the TMDs 504 may include an opening for the moonpool 522, such that the TMDs 504 are substantially ringed shaped containers.

[0042] In the current example, the platform 500 does not include mooring lines, however, it should be understood that mooring lines with or without hydraulic dampers may be utilized together with the moonpool 522 design in addition to or in lieu of the TMDs 504.

[0043] FIG. 6 illustrates another fixed ocean platform 600 that incorporates one or more tuned mass dampers 604 with integrated pumping and sensing systems 622 according to some implementation. In the current example, the fixed ocean platform 600 may be a FRP that includes a monopile 606 embedded in the soil and below a mudline 608 of the ocean or sea floor to secure or restrain the platform 600 against environmental loads (e.g., wind, waves, and the like). As discussed above, the monopile 606 is a large diameter circular column pile supporting the top structure 602. In the current example, the top structure 602 may support other payloads, such as14Aty Docket No.: E123-0006PCTturbines, oil and gas prospecting and / or extracting equipment, electoral systems, weather or environmental condition tracking equipment, refueling equipment, a combination thereof, and / or the like.

[0044] In the current example, an upper portion of the column of the monopile 606 is again partitioned into three TMDs 604(A) and (B). In the illustrated example, the TMDs 604 are in the form of liquid tanks being filled with a liquid (e.g., water, oil, or the like). In various implementations, a fill level may be adjusted based on environmental conditions external to and surrounding the platform 600. For example, the water depth, typical wind conditions, typical surf or wave conditions, and the like may be utilized to determine by external sensors, such as a wave probe 624 in the current example. It should be understood that additional external sensors, such as wind sensors, anemometer, barometers, pressure sensors, and / or the like. Once the external conditions are determined the pumping and sensing systems 622 may fill and / or discharge the liquid within the TMDs 604 to change the damping provided by each TMD 604 based on the current or present environmental conditions and / or loads.

[0045] In some cases, the TMDs 604 may be equipped with one or more sensor (such as a pressure sensor) to determine a fill level of each TMD 604 to assist in determining if the pumping and sensing systems 622 fills or discharges the liquid within the TMDs 604. In some cases, the liquid within the TMDs 604 may be stored in a storage tank (such as on the top surface) in a closed system (such as when the liquid is oil or the like). In other examples, the liquid may be water and, in these cases, the pumping and sensing systems 622 may be configured to extract and discharge the liquid to and from the surrounding environment (e.g., into and out of the surrounding water). In this example, the monopile 606 may include a discharge valve and / or an intake valve,15Aty Docket No.: E123-0006PCTgenerally indicated by 626(A) and 626(B), in fluid communication with the external water.

[0046] In some cases, the pumping and sensing systems 622 may adjust the liquid levels in the TMDs 604 based on a target frequency associated with the waves determined by the wave probe 624. In some cases, one or more machine learning models may be trained on wave probe data and TMD fill levels collected by existing platforms with TMDs and / or hydraulic dampers on mooring lines of differing volumes and dimensions to provide for dynamic adjustment of the TMDs and / or hydraulic dampers fill levels using the pumping and sensing systems 622. Accordingly, the one or more machine learning models may receive the wave probe data (and / or other environmental sensor data) as inputs and output the fill level for each corresponding TMD.

[0047] As described herein, the machine learned models may be generated using various machine learning techniques. For example, the models may be generated using one or more neural network(s). A neural network may be a biologically inspired algorithm or technique which passes input data (e.g., image and sensor data captured by the loT computing devices) through a series of connected layers to produce an output or learned inference. Each layer in a neural network can also comprise another neural network or can comprise any number of layers (whether convolutional or not). As can be understood in the context of this disclosure, a neural network can utilize machine learning, which can refer to a broad class of such techniques in which an output is generated based on learned parameters.

[0048] As an illustrative example, one or more neural network(s) may generate any number of learned inferences or heads from the captured sensor and / or image data. In some cases, the neural network may be a trained network architecture that is end-to-16Aty Docket No.: E123-0006PCTend. In one example, the machine learned models may include segmenting and / or classifying extracted deep convolutional features of the sensor and / or image data into semantic data. In some cases, appropriate truth outputs of the model in the form of semantic per-pixel classifications.

[0049] Although discussed in the context of neural networks, any type of machine learning can be used consistent with this disclosure. For example, machine learning algorithms can include, but are not limited to, regression algorithms (e.g., ordinary least squares regression (OLSR), linear regression, logistic regression, stepwise regression, multivariate adaptive regression splines (MARS), locally estimated scatterplot smoothing (LOESS)), instance-based algorithms (e.g., ridge regression, least absolute shrinkage and selection operator (LASSO), elastic net, least-angle regression (LARS)), decisions tree algorithms (e.g., classification and regression tree (CART), iterative dichotomiser 3 (ID3), Chi-squared automatic interaction detection (CHAID), decision stump, conditional decision trees), Bayesian algorithms (e.g., naive Bayes, Gaussian naive Bayes, multinomial naive Bayes, average one-dependence estimators (AODE), Bayesian belief network (BNN), Bayesian networks), clustering algorithms (e.g., k-means, k-medians, expectation maximization (EM), hierarchical clustering), association rule learning algorithms (e.g., perceptron, back-propagation, hopfield network, Radial Basis Function Network (RBFN)), deep learning algorithms (e.g., Deep Boltzmann Machine (DBM), Deep Belief Networks (DBN), Convolutional Neural Network (CNN), Stacked Auto-Encoders), Dimensionality Reduction Algorithms (e.g., Principal Component Analysis (PCA), Principal Component Regression (PCR), Partial Least Squares Regression (PLSR), Sammon Mapping, Multidimensional Scaling (MDS), Projection Pursuit, Linear Discriminant Analysis (LDA), Mixture Discriminant Analysis (MDA), Quadratic Discriminant17Aty Docket No.: E123-0006PCTAnalysis (QDA), Flexible Discriminant Analysis (FDA)), Ensemble Algorithms (e.g., Boosting, Bootstrapped Aggregation (Bagging), AdaBoost, Stacked Generalization (blending), Gradient Boosting Machines (GBM), Gradient Boosted Regression Trees (GBRT), Random Forest), SVM (support vector machine), supervised learning, unsupervised learning, semi-supervised learning, etc. Additional examples of architectures include neural networks such as ResNet50, ResNetlOl, VGG, DenseNet, PointNet, and the like. In some cases, the system may also apply Gaussian blurs, Bayes Functions, and / or a combination thereof.

[0050] FIG. 7 illustrates another fixed ocean platform 700 that incorporates one or more retrofitted or external tuned mass dampers 704 for restraining the fixed ocean platform 700 against environmental loads according to some implementation. In some cases, monopiles, such as monopile 706, may already be installed in the seafloor. In these cases, TMDs 704 may be installed as external TMDs 704 about the exterior of the monopile 706 as illustrated in the current example. In this example, two TMDs 704(A) and 704(B) are shown, however, it should be understood that a single ring shaped TMD 704 may be utilized to wrap the monopile 706 in a manner similar to that discussed above with the moonpool design of FIG. 5.

[0051] In the illustrated example, the TMDs 704 are again in the form of liquid tanks being filled with a liquid (such as oil, water, or the like) to a predetermined level, indicated by 710(A) and 710(B) for each corresponding TMD 704. In various implementations, the predetermined fill level 710(A) and 710(B) may be determined based on conditions associated with the environment surrounding the platform 700. For example, the water depth, typical wind conditions, typical surf or wave conditions, and the like may be utilized to determine the predetermined fill level 710(A) and 710(B) for each of the each corresponding TMD 704. It should be understood that the18Aty Docket No.: E123-0006PCTpredetermined fill level 710(A) and 710(B) may differ from each other or be the same. It should also be understood that the liquid in each TMD 704 may be the same or differ from one tank to the next.

[0052] FIG. 8 illustrates a top view of a tuned mass damper 800 for use with a fixed ocean platform according to some implementation. In the current example, the tuned mass damper 800 is partitioned into various segments, such as segments 802 and 804, via the bulkheads 806 and 808. Each of the segments 802 and / or 804 may be filled with fluid (e.g., either the same or different liquids). In some cases, the segments 802 and 804 may be watertight with respect to each other, while in other cases, the bulkheads 806 and / or 808 may be corrugated or liquid permeable to allow fluid from one to pass from one segment to another in a controlled or semi-controlled manner. For example, the bulkheads 806 and 808 may be utilized to slow the movement of fluid from one segment to another. In some cases, the segments 802 and 804 as well as the bulkheads 806 and 808 may be utilized to prevent or reduce flooding and / or increase a stiffness of the hull of the monopile and platform. In some cases, the segment 802 may be utilized to allow for a fluid free segment, such as to allow for storage of materials, passageways for platform operators, and / or the like.

[0053] In the current example, the tuned mass damper 800 is in the form of a ring around the monopile or moonpool. In other cases, the tuned mass damper 800 may be a circular tank or have other dimensions. In the current example, the segment 802 is smaller than the segment 804, however, it should be understood that any number of segments having various sizes and dimensions may be utilized to partition the tuned mass damper 800.

[0054] FIG. 9 illustrates a cross-sectional view of a tuned mass damper 900 for use with a fixed ocean platform according to some implementation. In the current example,19Aty Docket No.: E123-0006PCTthe interior of the tuned mass damper 900 may be filled with fluid 902, such as up to a liquid or fluid line 904. In this manner, the tuned mass damper 900 includes an unfilled portion 906 to allow for slushing or movement of the fluid 902 in response to environmental loads.

[0055] In the current example, the tuned mass damper 900 may also be filled with solid objects, such as the illustrated spheres 908. The solid objects 908 may be added or included within the tuned mass damper 900 to participate the motion when the platform undergoes dynamic forces (or dynamic environmental loads). For example, the solid objects 908 may increase the sloshing mass and the energy of the tuned mass damper 900 to, thereby, more effectively dissipate the load experienced by the platform.

[0056] FIG. 10 illustrates an example hydraulic damper 1000 for use with a mooring line of a fixed ocean platform according to some implementation. In the current example, the hydraulic damper 1000 may be configured between the mooring line 1002 and a top mooring assembly 1004. In the current example, the hydraulic damper 1000 may include a damping element 1006 coupled to a spring element 1008 as illustrated. For example, the damping element 1006 may be a viscous fluid (such as oil) that may compress in response to an environmental load and the spring element 1008 may be utilized as a restoring force to return the hydraulic damper 1000 to an equilibrium position when the environmental load subsides.

[0057] FIG. 11 further illustrates in diagram 1100 a relationship between the natural frequencies of exemplary FRP-monopiles implemented as described herein and wave frequencies. As illustrated in the diagram 1100, the systems and techniques described herein, including the use of high tension mooring lines and associated aspects described herein, may be used to implement an FRP-monopile structure 1110 with a wave frequency zone substantially below the natural frequencies corresponding to the 620Aty Docket No.: E123-0006PCTDOFs. As shown in this diagram, all of the 6 natural frequencies for surge, sway, heave, roll, pitch, and yaw are on the right side of the significant wave frequency (the peak in the diagram) where the wave energy is the largest. Thus, an FRP-monopile structure 1110 implemented according to the instant disclosure may experience minimal movement in both normal operating conditions and extreme (e.g., storm) conditions.

[0058] While the examples described herein may refer to FRP-monopiles 1110 used as supporting structures for wind turbines, the disclosed FRP-monopiles 1110 may be used to provide marine support for other objects, systems, and components, such as energy storage units, offshore substations, etc. Because the disclosed FRP-monopiles are not payload sensitive, FRP-monopiles 1110 as described herein may be scaled up and / or down as needed to support objects having a wide range of mass.

[0059] As described throughout the instant disclosure, mooring lines may be used to provide further stability to an FRP-monopile 1110. Mooring lines may be configured to maintain tension, in some examples, within a tension range. Over time, such mooring lines may loosen due to dynamic forces (e.g., wind, waves, currents, etc.). This loosening may result in mooring line tension falling outside of a design tension range, therefore reducing the ability of the loosened mooring lines to mitigate motion in the 6 DOFs. While re-tensioning systems and techniques have been successfully implemented for land-based applications and for floating marine platforms, these systems and techniques have not been successfully implemented for mooring lines used to stabilize fixed marine structures.

[0060] For example, the various systems and techniques available for re-tensioning in floating structures typically involve large increases or decreases in tension, preventing the fine tension adjustment often needed for FRP-monopile mooring lines. The FRP-monopile structures 1110 require stabilizing systems and techniques that21Aty Docket No.: E123-0006PCTaddress the higher wave loads that land-based structures are not subject to during tensioning of guide wires or during operation. The FRP -monopile structure stabilizing systems and techniques described herein address these issues while providing safer, easier, and more cost-effective means of applying and adjusting tension in the environments in which such structures are typically located.

[0061] For example, in a FRP monopile design, all its motions (namely surge, sway, heave, roll, pitch, and yaw) are restrained by the monopile and the moorings. In general, an FRP monopile is a stiffness-controlled structure with its lateral stiffness, e.g., produced by a combination of the monopile and the moorings, can be on the order of 30,000 kN / m. The vertical stiffness is on the order of 5,000,000 kN / m. For supporting a turbine with a payload under 3,000 MT (a downward force of 29,420 kN), the vertical stiffness is significantly high. As a result, all of its six natural frequencies (corresponding to the 6 DOF motions) are above the significant wave frequency zone. Consequently, this structure has less movement in normal operations and even storm conditions.

[0062] Based on the foregoing, it should be appreciated that technologies for minimizing movement of a fixed marine structure that may support a wind turbine have been presented herein. The subject matter described above is provided by way of illustration only and should not be construed as limiting. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure. Various modifications and changes may be made to the subject matter described herein without following the examples and applications illustrated and described, and without departing from the true spirit and scope of the present invention, which is set forth in the following claims.22Aty Docket No.: E123-0006PCT

[0063] Although the discussion above sets forth example implementations of the described techniques, other architectures may be used to implement the described functionality and are intended to be within the scope of this disclosure. Furthermore, although the subject matter has been described in language specific to structural features and / or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as exemplary forms of implementing the claims.23Atty Docket No.: E123-0006PCT

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A system, comprising:a monopile;a top side structure mounted to the monopile above a waterline, the top side structure to support a payload; andat least one tuned mass damper associated with the monopile, the at least one tuned mass damper filled with a liquid to a predetermined fill level.

2. The system of claim 1, further comprising:one or more anchors attached to a seabed; andone or more moorings that include a first end coupled to one or more attachments points on the monopile and a second end coupled to at least one of the one or more anchors, wherein the one or more moorings restricts movement of the monopile in six degrees of freedom.

3. The system of claim 2, wherein at least one of the one or more moorings includes a first segment coupled to a corresponding one of the one or more anchors and a second segment coupled to the monopile and the first segment is coupled to the second segment via a hydraulic damper.

4. The system of claim 3, wherein the second segment is coupled to the monopile via a top mooring assembly.24Atty Docket No.: E123-0006PCT5. The system of claim 2, wherein individual ones of the one or more moorings are tubular, and include vortex induced vibration suppression hardware to mitigate vortex-induced vibration.

6. The system of claim 1, wherein at least a portion of the monopile is embedded into a seabed.

7. The system of claim 1, wherein a seabed is greater than fifty meters under the waterline.

8. The system of claim 1, wherein the at least one tuned mass damper is at least three tuned mass dampers.

9. The system of claim 1, wherein the at least one tuned mass damper is above the waterline.

10. The system of claim 1, wherein the at least one tuned mass damper is below the waterline.

11. The system of claim 1, wherein the at least one tuned mass damper is at the waterline.25Aty Docket No.: E123-0006PCT12. A monopile, comprising:a first tuned mass damper integrated into a portion of the monopile, the first tuned mass damper including a tank filled with a first liquid to a first predetermined fill level; andwherein the monopile supports a top side structure above a waterline, the top side structure to support a payload.

13. The monopile of claim 12, further comprising:a pumping system in fluid communication with the first liquid within the tank and an exterior water source, the pumping system including:a sensor coupled to an exterior of the monopile, the sensor to generate environmental condition data; anda pump to fill or empty the tank based at least in part on the environmental condition data.

14. The monopile of claim 13, wherein the sensor is a wave probe.

15. The monopile of claim 13, wherein the first predetermined fill level is dynamic and the pumping system further comprises a processor to adjust the first predetermined fill level based at least in part on the environmental condition data and to cause the pump to fill the tank or empty the tank based at least in part on the first predetermined fill level.

16. The monopile of claim 13, wherein:the first predetermined fill level is dynamic;26Aty Docket No.: E123-0006PCTthe pumping system further comprises one or more machine learning models configured to receive the environmental condition data as an input and to output the first predetermined fill level as an output, the one or more machine learning models trained on historical environmental condition data, environmental load data to output the first predetermined fill level; andthe pump fills the tank or empties the tank based at least in part on the first predetermined fill level output by the one or more machine learning models.

17. The monopile of claim 12, wherein the first tuned mass damper includes at least one solid object within the tank.

18. The monopile of claim 12, wherein the tank of the first tuned mass damper includes at least two bulkheads to from a first segment of the tank and a second segment of the tank.

19. The monopile of claim 12, further comprising one or more mooring lines coupled to the monopile at a first end and to at least one anchor embed in a seafloor at a second end, each of the one or more mooring lines including a hydraulic damper.

20. The monopile of claim 12, wherein the monopile is a moonpool.27Aty Docket No.: E123-0006PCT

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