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Title:
TUBULAR OUTER WALLS FOR GRAVITY BASED STRUCTURES
Document Type and Number:
WIPO Patent Application WO/2017/011490
Kind Code:
A1
Abstract:
A tubular outer wall is provided for a gravity based structure and associated gravity based structures and systems. The tubular outer wall comprises a box structure comprising an inner plate, an outer plate, a first side plate, and a second side plate, and a plurality of tubulars disposed within the box structure for being of a more simple design than conventional tubular outer walls allowing for a cheaper and easier fabrication and assembly.

Inventors:
KHARRAZI MEHDI (US)
KNOLL DAVID ALEX (US)
SARWONO BAMBANG ABIMANJU (US)
Application Number:
PCT/US2016/041979
Publication Date:
January 19, 2017
Filing Date:
July 13, 2016
Export Citation:
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Assignee:
SHELL OIL CO (US)
SHELL INT RESEARCH (NL)
International Classes:
E02B17/00
Foreign References:
US3952527A1976-04-27
US4188157A1980-02-12
US20110305510A12011-12-15
US4002038A1977-01-11
US4648752A1987-03-10
Attorney, Agent or Firm:
HITCHCOCK, Thomas S. (US)
Download PDF:
Claims:
C L A I M S

1. A tubular outer wall for a gravity based structure.

2. The tubular outer wall of claim 1, wherein the tubular outer wall comprises a box structure comprising an inner plate, an outer plate, a first side plate, and a second side plate and a plurality of tubulars disposed within the box structure.

3. The tubular outer wall of claim 2, wherein the each of the inner plate, the outer plate, the first side plate, and the second side plate have a thickness in the range of from 0.125 inches to 5 inches.

4. The tubular outer wall of any one of claims 1-3, wherein the tubular outer wall has a trapezoid cross section.

5. The tubular outer wall of any one of claims 1-4, wherein the tubular outer wall has a rectangular cross section.

6. The tubular outer wall of any one of claims 1-5, wherein the inner plate and the outer plate have a length in the range of from 10 feet to 1500 feet and wherein the first side plate and the second side plate have a length in the range of from 2 feet to 30 feet.

7. The tubular outer wall of any one of claims 1-6, wherein the plurality of tubulars is arranged in one or more parallel rows.

8. The tubular outer wall of any one of claims 1-7, wherein the plurality of tubulars is arranged in a hexagonal packing arrangement.

9. The tubular outer wall of any one of claims 1-8, wherein the plurality of tubulars comprises a first row of tubulars filled with cement.

10. The tubular outer wall of any one of claims 1-9, wherein the first row of tubulars comprises 3 to 5000 parallel tubulars.

11. The tubular outer wall of any one of claims 1-10, wherein the box structure further comprises a top end plate and a bottom end plate.

12. The tubular outer wall of any one of claims 1-11, wherein plurality of tubulars comprise steel pipes having an outer diameter in the range of from 3 inches to 120 inches.

13. The tubular outer wall of any one of claims 1-2, wherein each one of the plurality of tubulars comprise two or more pipes joined together.

14. A gravity based structure comprising a tubular outer wall.

15. The gravity based structure of claim 14, wherein the tubular outer wall comprises the tubular outer wall of any one of claims 1-13.

16. The gravity based structure of claim 14 or 15, wherein the gravity based structure comprises

17. The gravity based structure of any one of claims 14-16, wherein the gravity based structure comprises 4 to 36 sides.

18. The gravity based structure of any one of claims 14-17, wherein the gravity based structure comprises a vertical outer wall, a sloped outer wall, a neck, and a wave deflector.

19. An offshore system comprising: a gravity based structure comprising a tubular outer wall and a sea floor, wherein the gravity based structure is resting on the sea floor.

20. The offshore system of claim 19, wherein the gravity based structure comprises the gravity based structure of any one of claims 14-18.

Description:
TUBULAR OUTER WALLS FOR GRAVITY BASED STRUCTURES

BACKGROUND

[0001] This application claims the benefit of U.S. Provisional Application No. 62/193,292, filed July 16, 2015, which is incorporated herein by reference.

BACKGROUND

[0002] The present disclosure relates generally to outer walls for gravity based structures. More specifically, in certain embodiments, the present disclosure relates to tubular outer walls for gravity based structures comprising parallel tubulars and associated systems and methods.

[0003] At offshore oil and gas sites, drilling and production top sides are typically supported by an offshore platform. Offshore platforms may either be floating platforms or fixed platforms. Examples of fixed platforms include gravity based structures. A gravity based structure is a support structure held in place by gravity that rests on the sea floor. Due to their strength and reliability, gravity based structures have been used extensively in the North Sea (i.e. offshore Norway and Scotland), offshore Canada, and offshore Russia.

[0004] Gravity based structures for use in Artie conditions must be designed to be capable of withstanding not only environmental loads but also loads due to sea ice. Conventional gravity based structures typically comprise an outer wall similar to the hull found on ice breaker ships. In certain embodiments, the outer wall may make up the gravity based structures outer skin. These outer walls may comprise scantling with numerous plates and stiffeners.

[0005] There are several problems with these conventional outer walls. The fabrication of these conventional outer walls can be complicated due to the large number of different sized individual components that make up the outer wall. The scantling of a conventional outer wall is typically made up of many pieces, including outer plates, stiffener webs, stiffener flanges, beam webs, beam flanges, girder webs, girder flanges, transverse girder webs, and transverse girder flanges. In addition, the conventional designs often requires thick plates that are costly and difficult to weld. Furthermore, conventional outer walls are limited in energy absorption for when extreme ice loads that were not expected are encountered.

[0006] It is desirable to develop a new outer wall for gravity based structures that is simple and inexpensive to fabricate and allows for greater energy absorption especially when loaded by extreme ice loads. SUMMARY

[0007] The present disclosure relates generally to outer walls for gravity based structures. More specifically, in certain embodiments, the present disclosure relates to tubular outer walls for gravity based structures comprising parallel tubulars and associated systems and methods.

[0008] In one embodiment, the present disclosure provides a tubular outer wall for a gravity based structure.

[0009] In another embodiment, the present disclosure provides a gravity based structure comprising a tubular outer wall.

[0010] In another embodiment, the present disclosure provides an offshore system comprising: a gravity based structure comprising a tubular outer wall and a sea floor, wherein the gravity based structure is resting on the sea floor.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011] A more complete and thorough understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings.

[0012] Figure 1 is an illustration of a cross sectional view of a tubular outer wall in accordance with certain embodiments of the present disclosure.

[0013] Figure 2 is an illustration of a cross sectional view of a gravity based structure comprising a tubular outer wall.

[0014] Figure 3 is an illustration of a cross sectional view of a gravity based structure comprising a tubular outer wall.

[0015] Figure 4 is an illustration of a gravity based structure system in accordance with certain embodiments of the present disclosure.

[0016] The features and advantages of the present disclosure will be readily apparent to those skilled in the art. While numerous changes may be made by those skilled in the art, such changes are within the spirit of the disclosure.

DETAILED DESCRIPTION

[0017] The present disclosure relates generally to outer walls for gravity based structures. More specifically, in certain embodiments, the present disclosure relates to tubular outer walls for gravity based structures comprising parallel tubulars and associated systems and methods. [0018] There may be several potential advantages to the tubular outer walls discussed herein. In certain embodiments, the tubular outer walls discussed herein may be of a more simple design than conventional tubular outer walls allowing for a cheaper and easier fabrication and assembly. In certain embodiments, the tubular outer walls discussed herein may also be more capable of handling sea ice impacts than conventional tubular outer walls because they may allow for better energy absorption for when extreme loads are encountered, such as those from ice ridges.

[0019] In certain embodiments, the present disclosure provides a tubular outer wall for a gravity based structure. As used herein, the term "tubular outer wall" describes an outer wall that comprises one or more tubular components. Referring now to Figure 1, Figure 1 illustrates a cross sectional view of tubular outer wall 100.

[0020] In certain embodiments, tubular outer wall 100 may comprise inner plate 110, outer plate 120, first side plate 130, second side plate 140, and one or more tubulars 150.

[0021] In certain embodiments, inner plate 110, outer plate 120, first side plate 130, and second side plate 140 may each comprise steel plates. In certain embodiments, each of the steel plates may have the same thickness. In certain embodiments each of the steel plates may have a thickness in the range of from 0.125 inches to 5 inches. In certain embodiments, the steel plates may be welded together in a box structure.

[0022] In certain embodiments, as shown in Figure 1, inner plate 110 and outer plate 120 may be parallel with each other and first side plate 130 and second side plate 140 may be parallel with each other. In such embodiments, tubular outer wall 100 may have a square or rectangular cross section.

[0023] In certain embodiments, not illustrated in Figure 1, inner plate 110 and outer plate 120 may be parallel with each other and first side plate 130 and second side plate 140 may be not parallel with each other. In such embodiments, tubular outer wall 100 may have a trapezoid cross section. In certain embodiments, the cross section of tubular outer wall 100 may be an isosceles trapezoid or a right trapezoid. For example, in certain embodiments, where tubular outer wall 100 has a trapezoid cross section, the angle between inner plate 110 and first side plate 130, and the angle between inner plate 110 and second side plate 140, may be in the range of from 10 degrees to 170 degrees. In other embodiments, for example when tubular outer wall 100 has a right trapezoid cross section, the angel between inner plate 110 and first side plate 130, or the angel between inner plate 110 and second side plate 140, may be in the range of from 10 degrees to 170 degrees.

[0024] In certain embodiments, inner plate 110 may have a length in the range of from 10 feet to 1500 feet. In certain embodiments, outer plate 120 may have a length in the range of from 10 feet to 1500 feet. In certain embodiments, first side plate 130 may have a length in the range of from 2 feet to 30 feet. In certain embodiments, second side plate 140 may have a length in the range of 2 feet to 30 feet.

[0025] In certain embodiments, the one or more tubulars 150 may comprise any conventional tubular commonly used in oil field applications. In certain embodiments, the one or more tubulars 150 may comprise steel pipes having an outer diameter in the range of from 3 inches to 120 inches and a thickness in the range of from 0.125 inches to 4 inches. In certain embodiments, each of the one or more tubulars 150 may comprise a single pipe or may comprise one or more pipes joined together. In certain embodiments, the one or more tubulars 150 may be filled with water, air, construction material and/or cement. In certain embodiments, the one or more tubulars 150 may have open ends or they may have capped ends. In certain embodiments, not illustrated in Figure 1, end plates may be welded to a top and bottom of tubular outer wall 100.

[0026] In certain embodiments, the one or more tubulars 150 may be arranged in one or more parallel rows. In certain embodiments, tubular outer wall 100 may comprise one, two, three, four, or five parallel rows of tubulars 150. As shown in Figure 1, tubular outer wall 100 may comprise a first row 151 of tubulars 150, a second row 152 of tubulars 150, and a third row 153 of tubulars 150. In certain embodiments, each of the tubulars 150 in each of the rows may be uniform in size. In other embodiments, the size of tubulars 150 in each of the rows are not uniform. In certain embodiments, all or a portion of the tubulars 150 in the first row 151 may be filled with cement.

[0027] In certain embodiments, the number of tubulars 150 in each row may depend on the size of the tubulars 150 and the length of inner plate 110 and outer plate 120. While Figure 1 illustrates ten tubulars 150 in first row 151, ten tubulars 150 in second row 152, and ten tubulars 150 in third row 153, many variations are possible. In certain embodiments, each row may independently comprise a number of tubulars in the range of from 3 to 5000. In certain embodiments, a portion of the tubulars 150 may be cut to fit the specific geometry of tubular outer wall 100.

[0028] In certain embodiments, tubulars 150 may be arranged within tubular outer wall 100 in a close packing arrangement. In certain embodiments, as shown in Figure 1, tubulars 150 may be arranged within tubular outer wall 100 in a square packing arrangement. In such embodiments, each tubular 150 in a portion of tubulars 150 contacts a single tubular 150 from each adjacent row. In other embodiments, tubulars 150 may be arranged within tubular outer wall 100 in a hexagonal packing arrangement. In such embodiments, each tubular 150 in a portion of tubulars 150 contacts two tubulars 150 from each adjacent row. In other embodiments, tubulars 150 may be arranged within tubular outer wall 100 in a random close packing arrangement.

[0029] In certain embodiments, any tubular 150 may be welded to any tubular 150 that it contacts. In addition, any tubular 150 may be welded to any plate that it contacts.

[0030] Referring now to Figure 2, Figure 2 illustrates a cross sectional elevation view of gravity based structure 1000. In certain embodiments, gravity based structure 1000 may comprise a conical gravity based structure. In other embodiments, not illustrated in Figure 2, gravity based structure 1000 may comprise a vertical gravity based structure. In certain embodiments, gravity based structure may comprise a hull 1001 surrounding internal structure 1200.

[0031] In certain embodiments, hull 1001 may comprise keel 1011, top 1012, and wall 1013. In certain embodiments, keel 1011 and/or top 1012 may be generally circular shaped portions. In certain embodiments, keel 1011 and/or top 1012 may be multifaceted shaped portions such as regular polygons with from 4 to 36 sides.

[0032] In certain embodiments, keel 1011 may be from 100 feet to 2000 feet in diameter. In certain embodiments, keel 1011 may be from 250-800 feet in diameter. In certain embodiments, keel 1011 may be capable of resting on a sea floor. In certain embodiments, top 1012 may be from 75 feet to 900 feet in diameter. In certain embodiments, top 1012 may be from 150-600 feet in diameter. In certain embodiments, top 1012 may be capable of supporting a topside.

[0033] In certain embodiments, wall 1013 may be located between keel 1011 and top 1012. In certain embodiments, wall 1013 may comprise vertical outer wall 1014, sloped outer wall 1015, neck 1016, and wave deflector 1017.

[0034] In certain embodiments, vertical outer wall 1014 may be a cylindrically shaped portion. In certain embodiments, vertical outer wall 1014 may be a multifaceted portion having the same cross sectional shape of keel 1011. In certain embodiments, vertical outer wall 1014 may have the same diameter of keel 1011. In certain embodiments, the height of vertical outer wall 1014 may be a function of water depth, ice depth, and/or the height of sloped outer wall 1015.

[0035] In certain embodiments, sloped outer wall 1015 may be a conically shaped portion. In certain embodiments, sloped outer wall 1015 may be a multifaceted portion having the same cross section of keel 1011. In certain embodiments, sloped outer wall 1015 may have a constant slope or a variable slope. In certain embodiments, the diameter of sloped outer wall 1015 may vary from a value equal to the diameter of vertical outer wall 1014 at the bottom of sloped outer wall 1015 to a value equal to the diameter of neck 1016 at the top of sloped outer wall 1015. In certain embodiments, the height of sloped outer wall 1015 may be a function of water depth, ice depth, and/or the height of vertical outer wall 1014.

[0036] In certain embodiments, neck 1016 may be a cylindrically shaped portion. In certain embodiments, neck 1016 may be a multifaceted portion having the same cross sectional shape of keel 1011. In certain embodiments, neck 1016 may have a diameter of from 75 feet to 600 feet. In certain embodiments, neck 1016 may have a diameter of from 150 feet to 400 feet. In certain embodiments, the length of neck 1016 may be a function of water, structural functionality and/or ice depth.

[0037] In certain embodiments, wave deflector 1017 may comprise a tapered portion 1017a and a vertical portion 1017b. In certain embodiments, tapered portion 1017a may have a constant taper or a variable taper. In certain embodiments, the diameter of tapered portion 1017a may vary from a value equal to the diameter of neck 1016 at a bottom of tapered portion 1017a to a value equal to the diameter of top 1012 at a top of tapered portion 1017a. In certain embodiments, tapered portion 1017a and vertical portion 1017b may be multifaceted portions having the same cross sectional shape of keel 1011.

[0038] In certain embodiments, internal structure 1200 may comprise internal bulkheads 1210 and flats 1220. In certain embodiments, bulkheads 1210 and flats 1220 may comprise any combination of features of conventional bulkheads and flats.

[0039] In certain embodiments, all or a portion of hull 1001 may comprise one or more tubular outer walls 1100. In certain embodiments, the one or more tubular outer walls 1100 may comprise any combination of features discussed above with respect to tubular outer wall 100. In certain embodiments, the one or more tubular outer walls 1100 may comprise inner plate 1110, outer plate 1120, bottom plate 1160, top plate 1170, first row 1151 of tubulars, second row 1152 of tubulars, and a third row 1153 of tubulars.

[0040] In certain embodiments, as shown in Figure 2, a cross section of vertical outer wall 1014 may comprise a single tubular outer wall 1100. In such embodiments, bottom plate 1160 of the tubular outer wall 1100 may be capable of resting on a seafloor or keel 1011 and inner wall 1110 may be welded to keel 1011 and/or any flats 1210 it contacts. In other embodiments, not shown in Figure 2, a cross section of vertical outer wall 1014 may comprise two or more tubular outer walls 1100. In such embodiments, a top tubular outer wall 1100 may be stacked on top of a bottom tubular wall 1100, wherein a bottom plate 1160 of the top tubular outer wall 1100 is connected to a top plate 1170 of the bottom tubular outer wall 1100.

[0041] In certain embodiments, as shown in Figure 2, a cross section of sloped outer wall 1015 may comprise a single tubular outer wall 1100. In such embodiments, bottom plate 1160 of the tubular outer wall 1100 may be capable of resting on vertical outer wall 1014 and inner wall 1110 may be welded to any bulkheads 1210 and/or flats 1220 that it contacts. In other embodiments, not shown in Figure 2, a cross section of sloped outer wall 1015 may comprise two or more tubular outer wall 1100. In such embodiments, a top tubular outer wall 1100 may be stacked on top of a bottom tubular wall 1100, wherein a bottom plate 1160 of the top tubular outer wall 1100 is connected to a top plate 1170 of the bottom tubular outer wall 1100.

[0042] In certain embodiments, as shown in Figure 2, a cross section of neck 1016 may comprise a single tubular outer wall 1100. In such embodiments, bottom plate 1160 of the tubular outer wall 1100 may be capable of resting on sloped outer wall 1015 and inner wall 1110 may be welded to any bulkheads 1210 and/or flats 1220 that it contacts. In other embodiments, not shown in Figure 2, a cross section of neck 1016 may comprise two or more tubular outer walls 1100. In such embodiments, a top tubular outer wall 1100 may be stacked on top of a bottom tubular wall 1100, wherein a bottom plate 1160 of the top tubular outer wall 1100 is connected to a top plate 1170 of the bottom tubular outer wall 1100.

[0043] In certain embodiments, as shown in Figure 2, a cross section of tapered portion 1017a may comprise a single tubular outer wall 1100. In such embodiments, bottom plate 1160 of the tubular outer wall 1100 may be capable of resting on neck 1016 and inner wall 1110 may be welded to any bulkheads 1210 and/or flats 1220 that it contacts. In other embodiments, not shown in Figure 2, a cross section of tapered portion 1017a may comprise two or more tubular outer walls 1100. In such embodiments, a top tubular outer wall 1100 may be stacked on top of a bottom tubular wall 1100, wherein a bottom plate 1160 of the top tubular outer wall 1100 is connected to a top plate 1170 of the bottom tubular outer wall 1100.

[0044] In certain embodiments, as shown in Figure 2, a cross section of vertical portion 1017b may comprise a single tubular outer wall 1100. In such embodiments, bottom plate 1160 of the tubular outer wall 1100 may be capable of resting on tapered portion 1017a and inner wall 1110 may be welded to any bulkheads 1210 and/or flats 1220 that it contacts. In other embodiments, not shown in Figure 2, a cross section of vertical portion 1017b may comprise two or more tubular outer walls 1100. In such embodiments, a top tubular outer wall 1100 may be stacked on top of a bottom tubular wall 1100, wherein a bottom plate 1160 of the top tubular outer wall 1100 is connected to a top plate 1170 of the bottom tubular outer wall 1100.

[0045] Referring now to Figure 3, Figure 3 illustrates another cross sectional plan view of a gravity based structure 1000. While the cross sectional plan view of Figure 3 is not described to be specifically along any portion of hull 1001, it is understood that the description below can equally apply to a cross section along each of vertical outer wall 1014, sloped outer wall 1015, neck 1016, tapered portion 1017a, and tapered portion 1017b.

[0046] Referring now to Figure 3, Figure 3 illustrates gravity based structure 2000. In certain embodiments, gravity based structure 2000 may comprise any combination of features discussed above with respect to gravity based structure 1000. In certain embodiments, gravity based structure 2000 may comprise hull 2001 and bulkheads 2200. In certain embodiments, hull 2001 may comprise one or more sides 2002. In certain embodiments, hull 2001 may comprise 4 to 36 sides. In certain embodiments, as shown in Figure 3, hull 2001 may comprise sixteen sides 2002.

[0047] In certain embodiments, as illustrated in Figure 3, each side 2002 of hull

2001 may comprise a single tubular outer wall 2100. In certain embodiments, tubular outer wall 2100 may comprise any combination of features discussed above with respect to tubular outer wall 1100 and/or tubular outer wall 100. In other embodiments, not illustrated in Figure 3, each side 2002 of hull 2001 may comprise two tubular outer walls 2100. In other embodiments, not illustrated in Figure 3, each side 2002 of hull 2001 may comprise 3 to 50 tubular outer walls 2100. In certain embodiments, for example when a side 2002 of hull 2001 comprises multiple tubular outer walls 2100, a first side plate of a first tubular outer wall 2100 may be welded to a second side plate of a second tubular outer wall 2100.

[0048] Referring now to Figure 4, Figure 4 illustrates an offshore platform system 3000 in accordance with certain embodiments of the present disclosure. In certain embodiments, offshore platform system 3000 may comprise gravity based structure 3100, a sea floor 3200, sea level 3300, and topsides 3400.

[0049] In certain embodiments, gravity based structure 3100 may comprise any combination of features discussed above with respect to gravity based structure 2000 and/or 1000. In certain embodiments, gravity based structure 3100 may rest on sea floor 3200 and support topsides 3400.

[0050] In certain embodiments, topsides 3400 may comprise any conventional topsides. In certain embodiments, topsides 3400 may comprise a drilling rig and/or production facilities.

[0051] While the embodiments are described with reference to various implementations and exploitations, it will be understood that these embodiments are illustrative and that the scope of the inventive subject matter is not limited to them. Many variations, modifications, additions and improvements are possible.

[0052] Plural instances may be provided for components, operations or structures described herein as a single instance. In general, structures and functionality presented as separate components in the exemplary configurations may be implemented as a combined structure or component. Similarly, structures and functionality presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements may fall within the scope of the inventive subject matter.