AU2012229397A1 - Systems, methods and assemblies for supplying power to an offshore facility - Google Patents

Abstract

The present invention is directed to processes and systems that use wave energy to drive one or more air turbines associated with an offshore facility, wherein such turbines can generate electrical power for use on the offshore facility and/or adjacent facilities and equipment. The offshore facility can be an offshore platform or a floating vessel. The turbine can be housed within a structural member of the facility or a tubular member suspended from the facility. The turbine can also be housed within a tubular member connected to a structural member of the facility.

Description

WO 2012/125393 PCT/US2012/028214 SYSTEMS, METHODS AND ASSEMBLIES FOR SUPPLYING POWER TO AN OFFSHORE FACILITY RELATED APPLICATIONS [0001] This application claims the benefit of, and priority to U.S. Provisional Patent Application No. 61/451,649 filed on March 11, 2011, and U.S. Provisional Patent Application No. 61/555,325 filed on November 3, 2011. FIELD OF THE INVENTION [0002] This invention relates generally to use of renewable energy to provide power on offshore oil and gas facilities, and specifically to the use of low-head hydro-air turbines to produce said power from wave-induced air pressure. BACKGROUND [0003] Offshore oil and gas platforms have tremendous electrical power needs. The electrical loads on fixed and floating offshore facilities are typically supplied by fossil fuel driven power generating equipment (e.g., diesel generators). Smaller loads, less than about 50 kW, are often supplied by small-scale renewable energy generators such as solar panels or micro-wind turbines. Examples of facilities having such power requirements are fixed platforms having legs extending to the sea floor, floating platforms that are typically secured to the sea floor with lines, and floating production storage and offloading (FPSO) vessels. [0004] In view of the foregoing, methods and systems for producing/generating larger (e.g., greater than 50 kW) electrical power loads from renewable energy sources would be very beneficial-particularly wherein such methods/systems take up minimal space and/or are utilized/positioned in a manner that does not challenge the spatial constraints that exist perennially on such offshore platforms. SUMMARY [0005] The present invention is directed to methods, systems, and assemblies that use wave energy to drive one or more air turbines associated an offshore hydrocarbon facility, wherein such turbines can generate electrical power for use on the offshore facility and/or nearby exploration and production (E&P) facilities and equipment. 1 WO 2012/125393 PCT/US2012/028214 [0006] In some embodiments, the present invention is directed to one or more methods for harnessing or otherwise capturing wave energy for use on an offshore oil and/or gas platform, the methods comprising the steps of: (1) incorporating an oscillating water column into an offshore oil and/or gas platform, wherein water, driven by wave energy, enters and leaves from an inlet/outlet port that is integrated into the platform's structure, and wherein the inward/outward flow of water raises and lowers the water level in the oscillating water column, thereby effecting pressure changes in the air residing above the water in said column; (2) utilizing the pressure changes in the air above the oscillating water column to drive a hydro-air turbine (e.g., Wells-type turbine) that is coupled with an electric power generating device (e.g., a rotating alternator) so as to generate electric power; and (3) using (e.g., via a power take-off cable) the electric power to power devices on or near the offshore oil/gas platform. [0007] In some other embodiments, the present invention is directed to one or more systems for harnessing or otherwise capturing wave energy for use on an offshore oil and/or gas platform, the system comprising the following components: (1) an offshore oil and/or gas platform having a support structure, wherein said support structure comprises a columnar volume with a common inlet/outlet port at water level; (2) an oscillating water column within the columnar volume of the support structure, the oscillating water column having an oscillating (rising/falling) water level, the water level in said column being raised and lowered by wave-induced flow of water into and out of the common inlet/outlet; (3) a variable volume of air above the water level; (4) a hydro-air turbine (e.g., a Wells-type turbine) housed in the columnar volume of the support structure above the water level and variable volume of air, wherein the turbine rotates in response to changes in the air volume above the water level; (5) a rotating alternator (or other similar device) driven by the turbine via a shaft; (6) an air intake/discharge opening located above the turbine; and (7) a power take-off cable connected to the rotating alternator on one end, and one or more electrical devices on another end. [0008] The foregoing has outlined rather broadly the features of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. 2 WO 2012/125393 PCT/US2012/028214 BRIEF DESCRIPTION OF THE DRAWINGS [0009] For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which: [0010] Figure 1 is a schematic environmental view of an offshore facility in accordance with one or more embodiments of the present invention; [0011] Figure 2 is a schematic view of a power generating assembly and system with air turbine positioned within a support structure of the facility of Figure 1, in accordance with one or more embodiments of the present invention; and [0012] Figure 3 is a schematic view of an alternative embodiment of the power generating assembly and system Figure 2. DETAILED DESCRIPTION [0013] As mentioned in the foregoing section, the present invention is directed to processes, methods, assemblies and systems that utilize wave energy to drive one or more air turbines incorporated into or otherwise associated with an offshore facility, wherein such turbines can generate electrical power for use on or near the offshore facility. [0014] Referring to Figure 1, an offshore facility 11 is shown with its operating area above the surface of the sea 13. Facility 11 is illustrated as a fixed platform, but is not intended to limit the scope of this disclosure as other types of facilities have already been discussed and are contemplated. Typically, a plurality of risers 15 extend from facility 11 to subsea wellheads 17 positioned on the seafloor 19. Risers 15 and wellheads 17 are illustrated as production risers and wellheads, but those skilled in the art will easily appreciate that the scope of the present disclosure would also include risers and subsea assemblies associated with drilling operations. In embodiment illustrated in Figure 1, a plurality of legs or supports 21 extend between facility 11 and the sea floor 19 to provide stability for facility 11. In alternative embodiments of facility 11, supports 21 may be anchor or mooring lines. Supports 21 of the embodiment shown in Figure 1 preferably have at least a portion with a hollow interior. [0015] Referring to Figure 2, at least one embodiment of a power generating assembly and system 200 is shown. In the embodiment shown in Figure 2, assembly and system 200 3 WO 2012/125393 PCT/US2012/028214 includes a support structure 201, support structure 21 in Figure 1. The hollow interior of support structure 201 defines a columnar volume with a common opening 211 at sea or water level 213. In the embodiment shown in Figure 2, opening is formed through a sidewall of structure 211. Water enters and exits the columnar volume of support structure 201 through opening 211, thereby allowing the waterline within columnar volume to oscillate as the water level rises and lowers with the waves. Such oscillating water level defines an oscillating water column 203 within support structure 211, having a variable volume of air above the water level. [0016] A turbine 205 is housed in the columnar volume of support structure 201 above the water level and variable volume of air. Turbine 205 can be either a single-stage turbine or a multi-stage turbine. Turbine 205 rotates in response to changes in the air pressure due to the increasing and decreasing volume associated with oscillating water column 203. A rotating alternator 209 (or other similar device) is mechanically driven by a shaft of turbine 205 to generate electricity responsive to the rotation of turbine 205. A power take-off cable 215 is connected to the rotating alternator, so that one or more electrical devices are in electrical communication with alternator 209. Another opening 207 is formed through support structure 201, above turbine 205 to allow air flow into and out of the columnar volume. [0017] Referring to Figure 3, at least one additional embodiment of a power generating assembly and system 300 is shown. In the embodiment shown in Figure 3, assembly and system 300 includes a tubular member 302 suspended from facility 11 (Figure 1). Figure 3 illustrates tubular member 302 as being adjacent to a support structure 301 merely for the purpose of illustrating that tubular member is different from support structures 301 of facility 11. Tubular member can be a blank riser or casing suspended from a platform or over the side of an FPSO depending on the embodiment of the system. In the illustration of Figure 3, tubular member 302 has a hollow interior of that defines a columnar volume with a common opening 311 at sea or water level 313. In the embodiment shown in Figure 3, opening 311 is formed at a lower end of tubular member 302, but it would also be through a sidewall similar to opening 211 of Figure 2. Water enters and exits the columnar volume of tubular member 302 through opening 311, thereby allowing the waterline within columnar volume to oscillate as the water level rises and lowers with the waves. Such oscillating water level defines an oscillating water column 303 within tubular member 302, having a variable volume of air above the water level. 4 WO 2012/125393 PCT/US2012/028214 [0018] A turbine 305 is housed in the columnar volume of tubular member 302 above the water level and variable volume of air. Turbine 305 can be either a single-stage turbine or a multi-stage turbine. Turbine 305 rotates in response to changes in the air pressure due to the increasing and decreasing volume associated with oscillating water column 303. A rotating alternator 309 (or other similar device) is mechanically driven by a shaft of turbine 305 to generate electricity responsive to the rotation of turbine 305. A power take-off cable 315 is connected to the rotating alternator, so that one or more electrical devices are in electrical communication with alternator 309. Another opening 307 is formed through tubular member 302, above turbine 305 to allow air flow into and out of the columnar volume. 2. Processes [0019] In some embodiments, the present invention is directed to methods for producing power from wave energy for use on an offshore facility, the method comprising the steps of: (1) incorporating an oscillating water column into an offshore facility, wherein water, driven by wave energy, enters and leaves from an opening that is integrated into the facility's structure, and wherein the inward/outward flow of water raises and lowers the water level in the oscillating water column, thereby effecting pressure changes in the air residing above the water in said column; (2) utilizing the pressure changes in the air above the oscillating water column to drive a turbine (e.g., a Wells-type turbine) that is coupled with an electric power generating device (e.g., a rotating alternator) so as to generate electric power; and (3) using (e.g., via a power take-off cable) the electric power to power devices on the offshore facility. [0020] Oscillating water columns (OWCs), as well as the use of OWCs in harnessing wave are known in the art. Examples of such OWCs can be found in Nishikawa, U.S. Patent No. 4,719,754; and in Sieber, U.S. Patent No. 7,836,689. [0021] In some embodiments, the present invention is directed to methods for producing power from wave energy for use on an offshore facility, the method comprising the steps of: (1) associating an oscillating water column with an offshore facility, wherein water, driven by wave energy, enters and leaves from an opening that is integrated into a tubular member suspended from the facility, and wherein the inward/outward flow of water raises and lowers the water level in the oscillating water column, thereby effecting pressure changes in the air residing above the water in said column; (2) utilizing the pressure changes in the air above the oscillating water column to drive a turbine (e.g., a Wells-type turbine) that is coupled with an electric power-generating device (e.g., a rotating alternator) so as to generate electric 5 WO 2012/125393 PCT/US2012/028214 power; and (3) using (e.g., via a power take-off cable) the electric power to power devices on the offshore facility. [0022] In further embodiments, the present invention is directed to methods for producing power from wave energy for use on an offshore facility, the method comprising the steps of: (1) associating an oscillating water column with an offshore facility, wherein water, driven by wave energy, enters and leaves from an opening that is integrated into a tubular member, and wherein the inward/outward flow of water raises and lowers the water level in the oscillating water column, thereby effecting pressure changes in the air residing above the water in said column; (2) utilizing the pressure changes in the air above the oscillating water column to drive a turbine (e.g., a Wells-type turbine) that is coupled with an electric power-generating device (e.g., a rotating alternator) so as to generate electric power; and (3) using (e.g., via a power take-off cable) the electric power to power devices on the offshore facility. The tubular member can suspended from the facility or a structural support of the facility. Tubular member can be suspended from a platform or positioned adjacent a vessel depending on the type of facility. [0023] In some embodiments, the above-identified turbines can be single- and/or multi-stage turbines. In some such above-described embodiments, the turbine so utilized is a unidirectional turbine, wherein such turbines rotate in response to changes in the air volume above the water level, and wherein the turbine rotates in the same direction regardless of whether the volume of air is increasing or decreasing. Examples of such turbines include, but are not limited to, Wells turbines and Savonius turbines. See, for example, Wells, U.S. Patent No. 4,383,413. Additionally or alternatively, in some or other such embodiments, reciprocating turbines can be employed in lieu of, or in addition to, any unidirectional turbines so utilized. [0024] In some embodiments, there are a number of power take-off scenarios. Such scenarios include, but are not limited to, (a) turbine direct drive of a generator, connected to battery storage or directly to a busbar load, and (b) turbine direct or electric drive of an air compressor for storage in an accumulator, wherein the air would be discharged on demand to drive either an in-leg turbine or a separate air turbine for rapid power delivery to a bus. It is contemplated that, in some such embodiments, the compressed air from the accumulator will be used to increase the efficiency of combustion turbines on the platforms by boosting the intake air pressure and/or temperature. 6 WO 2012/125393 PCT/US2012/028214 [0025] In some such above-described method embodiments, the method is capable of generating electrical power loads in excess of 50 kW. In some or other such embodiments, the method is capable of generating electrical power loads in excess of 100 kW. 3. Systems [0026] Systems are generally consistent with implementing the methods described above via a functional infrastructure as described in the passages which follow. [0027] As mentioned previously herein, in some embodiments the present invention is directed to a system for producing power from wave energy for use on an offshore facility. With reference to Figure 2, such system systems and assemblies (200) can comprise the following components: an offshore facility having a support structure 201, wherein said support structure 201 comprises a columnar volume with a common opening 211 at water level 213; an oscillating water column 203 within the columnar volume of the support structure 201, the oscillating water column 203 having an oscillating water level, the water level in said column being raised and lowered by wave-induced flow of water into and out of the common opening 211; a variable volume of air above the water level; a turbine 205 housed in the columnar volume of the support structure 201 above the water level and variable volume of air, wherein the turbine 205 rotates in response to changes in the air volume above the water level; a rotating alternator 209 (or other similar device) driven by the turbine via a shaft; an air opening 207 located above the turbine; and a power take-off cable 215 connected to the rotating alternator on one end, and one or more electrical devices on another end. [0028] In some such above-described system embodiments, one or more turbines can be positioned in one or more legs of the offshore oil/gas platform. In some such embodiments, the leg is modified with an external plenum, thereby increasing flow volume to the turbine inside and/or outside of the leg. [0029] As mentioned previously herein, in some embodiments the present invention is directed to a system for producing power from wave energy for use on an offshore facility. With reference to Figure 3, such system systems and assemblies 300 can comprise the following components: an offshore facility having a tubular member 302, wherein said tubular member 302 comprises a columnar volume with a common opening 311 at water level 313; an oscillating water column 303 within the columnar volume of the tubular member 302, the oscillating water column 303 having an oscillating water level, the water 7 WO 2012/125393 PCT/US2012/028214 level in said column being raised and lowered by wave-induced flow of water into and out of the common opening 311; a variable volume of air above the water level; a turbine 205 housed in the columnar volume of tubular member 302 above the water level and variable volume of air, wherein turbine 305 rotates in response to changes in the air volume above the water level; a rotating alternator 309 (or other similar device) driven by the turbine via a shaft; an air opening 307 located above the turbine; and a power take-off cable 315 connected to the rotating alternator on one end, and one or more electrical devices on another end. [0030] In some such above-described system embodiments, one or more turbines can be positioned in one or more tubular members 302 associated with the offshore facility 11. [0031] In some such above-described system embodiments, one or more turbines can be positioned on the deck of the offshore facility. In some such embodiments, each leg or support structure (of the platform) is coupled to a turbine, with or without leg modifications to create external plenums. In some or other such embodiments, two or more legs or support structures are coupled to a common air manifold. [0032] While the type and size of existing offshore facilities will likely place restrictions on the size and number of OWC/hydro-air turbine power generation systems, it is contemplated that future such facilities could be developed to better incorporate this technology into the overall power generation scheme for the offshore facility. [0033] The methods and systems described above are easily adaptable for a variety of circumstances. For example, if a plurality of such turbines are used, they could be used individually or in series. Also, structural and/or environmental restrictions may direct or otherwise dictate how air is introduced and discharged from the system (vide supra). 5. Summary [0034] The present invention is directed to methods and systems that use wave energy to drive one or more air turbines associated with an offshore facility, wherein such turbines can generate electrical power for use on the offshore facility and/or adjacent facilities and equipment. [0035] All patents and publications referenced herein are hereby incorporated by reference to an extent not inconsistent herewith. It will be understood that certain of the above-described structures, functions, and operations of the above-described embodiments are not necessary to practice the present invention and are included in the description simply for completeness of an exemplary embodiment or embodiments. In addition, it will be understood that specific 8 WO 2012/125393 PCT/US2012/028214 structures, functions, and operations set forth in the above-described referenced patents and publications can be practiced in conjunction with the present invention, but they are not essential to its practice. It is therefore to be understood that the invention may be practiced otherwise than as specifically described without actually departing from the spirit and scope of the present invention as defined by the appended claims. 9

Claims (19)

1. A method for producing power from wave energy for use on an offshore facility, the method comprising the steps of: a) positioning a tubular member associated with an offshore facility in communication with the water, the tubular member having an opening for waves from the water to enter in exit the tubular member, the inward/outward flow of water raises and lowers the water level in the tubular member thereby defining an oscillating water column within the tubular member and thereby effecting pressure changes in the air residing above the water in column; b) utilizing the pressure changes in the air above the oscillating water column to drive a turbine that is coupled with an electric power-generating device so as to generate electric power; and c) using the electric power to power devices on the offshore facility.

2. The method of claim 1, wherein the tubular member is suspended from the facility.

3. The method of claim 1, wherein the tubular member is formed in a structural support of the facility.

4. The method of claim 1, where: the facility is an offshore oil platform; and the tubular member is formed in a structural support of the facility.

5. The method of claim 1, where: the facility is an offshore oil platform; and the tubular member is suspended from the platform.

6. The method of claim 1, where: the facility is an offshore oil platform; and the tubular member connected to a structural support of the platform. 10 WO 2012/125393 PCT/US2012/028214

7. The method of claim 1, where: the facility is a floating vessel; and the tubular member is formed in a structural support of the facility.

8. A system for producing power from wave energy for use on an offshore facility, comprising: an offshore facility having a tubular member positioned adjacent a water level, the tubular member having a columnar volume with an opening at sea level; an oscillating water column within the columnar volume of the tubular member, the oscillating water column having an oscillating water level, the water level in the column being raised and lowered by wave-induced flow of water into and out of the common opening; a variable volume of air above the water level; a turbine housed in the columnar volume of tubular member above the water level and variable volume of air, the turbine rotates in response to changes in the air volume above the water level; a rotating alternator driven by the turbine; an air opening located above the turbine; and a power cable connected to the rotating alternator that communicates electrical power to one or more electrical devices associated with the facility.

9. The system of claim 8, wherein the tubular member is suspended from the facility.

10. The system of claim 8, wherein the tubular member is formed in a structural support of the facility.

11. The system of claim 8, where: the facility is an offshore oil platform; and the tubular member is formed in a structural support of the facility. 11 WO 2012/125393 PCT/US2012/028214

12. The system of claim 8, where: the facility is an offshore oil platform; and the tubular member is suspended from the platform.

13. The system of claim 8, where: the facility is an offshore oil platform; and the tubular member connected to a structural support of the platform.

14. The system of claim 8, where: the facility is a floating vessel; and the tubular member is formed in a structural support of the facility.

15. The system of claim 8, wherein a plurality of turbines are housed within the columnar volume of tubular member above the water level and variable volume of air.

16. The system of claim 8, wherein there are a plurality of tubular members with each tubular member a columnar volume and a turbine housed therein.

17. The system of claim 8, wherein: there are a plurality of tubular members with each tubular member a columnar volume; and there are a plurality of turbines are housed within each of the columnar volumes above the water level.

18. The system of claim 8, wherein the tubular member further comprises an air opening formed above the turbine.

19 A system for producing power from wave energy for use on an offshore facility, comprising: a) an offshore facility having a support structure, the support structure having a columnar volume with a first opening at water level; 12 WO 2012/125393 PCT/US2012/028214 b) an oscillating water column within the columnar volume of the support structure, the oscillating water column having an oscillating water level, the water level being raised and lowered by wave-induced flow of water into and out of the first opening; c) a variable volume of air above the water level, the variable volume varying in response to oscillation of the water level; d) a turbine housed in the columnar volume of the support structure above the water level and variable volume of air, the turbine rotates in response to changes in the variable volume; e) a rotating alternator driven by the turbine; f) an air opening located above the turbine; and g) a power take-off cable connected to the rotating alternator to power or more electrical devices associated with the facility. 13