Offshore platform for arctic environments

• US 3,952,527 A
• Filed: 11/11/1974
• Issued: 04/27/1976
• Est. Priority Date: 12/11/1972
• Status: Expired due to Term

• Current Assignee: Edward R. Vinieratos, Frank W. Purdy, Robert E. Levien
• Original Assignee: Edward R. Vinieratos, Frank W. Purdy, Robert E. Levien
• Inventors: Vinieratos, Edward R., Purdy, Frank W., Levien, Robert E.
• Primary Examiner(s): Shapiro, Jacob
• Application Number:
  US05/522,776
• Time in Patent Office: 533 Days
• Field of Search: 61/46.5, 61/46, 61/50, 61/1 R, 62/259, 62/260, 175/9, 165/47, 114/40, 114/42, 9/8 P
• US Class Current: 405/217
• CPC Class Codes: E02B 17/0021 against ice-loads
• CPC Class Codes: E02B 17/027 steel structures E02B17/021 takes precedence
• CPC Class Codes: E02B 2017/0065 Monopile structures
• CPC Class Codes: E02B 2017/0086 Large footings connecting several legs or serving as a reservoir for the storage of oil or gas

Abstract

Offshore platform for resisting the pressure of external ice formations in which the base is generally frustoconical having upwardly and inwardly sloping surfaces. The upper part of the structure is an inverted cone frustum with upwardly and outwardly sloping surfaces to deflect the ice as it rides up and base. The waist surface is rounded. The interior of the platform is formed of vertical tubes which are filled with frozen hard material to assist the structure in resisting external forces.

Claims

1. A movable offshore structure for resisting external ice forces and for supporting working platforms and the like comprising:

a. a generally side-enclosed external shell defined by a lower base position with an upwardly and inwardly angling surface and an upper supporting section with an upwardly and outwardly extending surface, said upper and lower sections together defining a waist deflector area, said offshore structure being substantially closed on the bottom so as to be made bouyant and floatable,

b. a plurality of compartments within said shell, each capable of being independently filled with and emptied of freezable fill material, so that when said compartments are filled the structure will rest on the ocean floor and when empty the structure will be floatable and movable, said compartments being supported relative to one another by an internal supporting framework,

c. refrigeration means for freezing said fill material, and

d. at least one working deck located generally on top of said shell and said compartments for supporting work equipment and the like.

2. The offshore structure according to claim 1 and wherein said structure is designed so that when filled and resting on the ocean floor the water surface will be generally below the waist deflector area.

3. The offshore structure according to claim 1 and wherein said compartments will extend to above water level within said shell.

4. The offshore structure according to claim 1 and wherein said compartments and framework occupy substantially all of the base and waist portions and a substantial part of the upper supporting section.

5. The offshore structure according to claim 1 and wherein the angle of the upwardly and inwardly extending surface of the base portion is from about 20°

to about 60°

from the horizontal.

6. The offshore structure according to claim 1 and wherein at least one drillway shaft extends from the top to the bottom of said structure to permit drilling operations from said working platform into the ocean floor.

7. An offshore structure for resisting external ice forces and for supporting working platforms and the like comprising:

a. a continuous external shell generally circular in horizontal cross-sectional configuration and externally defined by a lower base portion of generally frusto-conical shape with an upwardly and inwardly extending surface and an upper supporting section with an upwardly and outwardly extending surface, said upper and lower sections together defining a waist deflector area therebetween,

b. a plurality of generally watertight compartments within said shell, each capable of being independently filled with and emptied of freezable fill material, said compartments being closed and arranged so that the bottom of said structure is substantially closed, said compartments being supported relative to one another by an internal supporting framework,

c. refrigeration means for freezing said fill material, and

d. at least one working deck located generally on top of said shell and said tubes for supporting work equipment and the like.

8. The offshore structure according to claim 7 and wherein at least some of said compartments are defined by generally horizontally disposed and spaced apart dividing walls.

9. The offshore structure according to claim 8 and wherein said compartments and framework occupy substantially all of the base and waist portions and a substantial part of the upper supporting section.

10. The offshore structure according to claim 7 and wherein the angle of the upwardly and inwardly extending surface of the base portion is from about 20°

to about 60°

from the horizontal.

11. The offshore structure according to claim 7 and wherein at least one open drillway shaft extends from the top to the bottom of said structure to permit drilling operations from said working platform into the ocean floor.

12. An offshore structure for resisting external ice forces and for supporting platforms and the like, comprising:

a. a side-enclosed base structure comprising walls having top and bottom ends and in which the walls of said structure slope generally inwardly and upwardly from said bottom end to said top end, said bottom end being adapted to extend from below the ice level and said top end being adapted to extend above the water and ice levels;

b. frozen hard fill material substantially filling the interior of said base structure to add compressive strength and stability to said structure against external forces bearing thereagainst; and

c. heat transfer means within the interior of said base structure for removing heat from and maintaining said frozen hard fill material in its frozen state.

13. The offshore structure according to claim 12 and wherein said heat transfer means for removing heat comprises an artificial refrigeration system.

14. The offshore structure according to claim 13 and wherein said bottom end of said base structure extends to the watter floor.

15. The offshore structure according to claim 14 and wherein said upper end of said structure is provided with cover means to cover said frozen hard fill material and minimize the transfer of heat into said hard fill material.