Method and apparatus for conducting subaqueous operations in ice conditions

• US 4,068,487 A
• Filed: 04/30/1976
• Issued: 01/17/1978
• Est. Priority Date: 04/30/1976
• Status: Expired due to Term

• Current Assignee: WHITFIELD, JOHN H.; ROUTE 3, BOX 28A, HANCEVILLE, .
• Original Assignee: The Offshore Company
• Inventors: Pease, Floyd Tim, Reusswig, Gerhard Helmut, Edling, Porter Russell
• Primary Examiner(s): Shapiro, Jacob
• Application Number:
  US05/682,187
• Time in Patent Office: 627 Days
• Field of Search: 61/86, 61/93, 61/103, 175/7, 175/8, 175/9, 104/35, 104/98, 104/175, 105/163, 105/29 R, 114/264, 114/265, 9/8
• US Class Current: 405/201
• CPC Class Codes: B63B 2211/06 Operation in ice-infested waters
• CPC Class Codes: B63B 35/4413 Floating drilling platforms, e.g. carrying water-oil separating devices
• CPC Class Codes: E02B 17/02 placed by lowering the supporting construction to the bottom, e.g. with subsequent fixing thereto
• CPC Class Codes: E21B 15/003 adapted to be moved on their substructure, e.g. with skidding means; adapted to drill a plurality of wells
• CPC Class Codes: E21B 7/008 Drilling ice or a formation covered by ice
• CPC Class Codes: E21B 7/128 from floating support with independent underwater anchored guide base

Abstract

An improved platform for performing subaqueous operations in ice conditions. A substructure on the platform supports the equipment for performing the subaqueous operation and straddles an aperture through the platform. Means are secured to the underside of the substructure for presenting a relatively low coefficient of friction or low lateral resistance between the underside of the substructure and the face of the platform. Locomotion means are associated with substructure for moving the substructure laterally over the face of the platform relative to the aperture whereby the equipment for performing the subaqueous operations may remain over the wellhead in spite of certain magnitudes of lateral movement of the platform responsive to the ice conditions.

Claims

1. An improved platform from which subaqueous operations are performed in ice conditions, the platform having an aperture therethrough through which the subaqueous operations are performed, the improvement comprising:

at least two lower skid beams secured to the face of the platform, the two lower skid beams being positioned parallel to each other on opposite sides of the aperture;

at least two upper skid beams positioned to the top of the lower skid beams, the two upper skid beams being positioned parallel to each other on opposite sides of the aperture;

a substructure for supporting equipment for performing the subaqueous operations positioned atop the upper skid beams;

at least one carriage rail mounted longitudinally along selected lengths of each of said upper skid beams and said lower skid beams;

at least two travelling members carried by the underside of the substructure, each travelling member being associated with an upper skid beam, each of such travelling member including a wheel for communicating with the carriage rail mounted on such upper skid beam and presenting relatively low lateral resistance between the substructure and the upper skid beam whereby the substructure may move in either direction longitudinally along the upper skid beams;

at least two travelling members carried by the underside of the upper skid beams, each travelling member being associated with a lower skid beam, each of such travelling members including a wheel for communicating with the carriage rail mounted on such lower skid beam and presenting relatively low lateral resistance to the movement of the upper skid beam relative to the lower skid beam whereby the upper skid beams may move in either direction longitudinally along the lower skid beams;

a gear rack mounted longitudinally along selected lengths of each of said upper and lower skid beams;

a drive pinion carried by each of the travelling members and in communication with gear rack mounted on the respective skid beam with which the travelling member is associated;

a drive motor associated with each travelling member and operatively coupled to the drive pinion for generating motive forces to revolve the drive pinion whereby the substructure may be moved in either direction longitudinally along the upper skid beam and the upper skid beams may be moved in either direction longitudinally along the lower skid beams.

2. In an improved platform from which subaqueous operations are performed in ice conditions, the platform having an aperture therethrough through which the subaqueous operations are performed and having a substructure carried by the platform for supporting the equipment for performing subaqueous operations, said substructure being positioned such that it straddles the aperture and said substructure preferably remaining in a fixed lateral position with respect to the subaqueous operations being performed by the equipment supported by such substructure, an improved apparatus associated with the underside of the substructure for presenting relatively low lateral resistance to the movement of the platform horizontally beneath the fixed position substructure comprising:

at least two first guide means carried by the platform in parallel relationship with each other, one of such first guide means being on each side of the aperture;

at least two second guide means positioned in parallel relationship with each other, one of such second guide means being on either side of the aperture, said second guide means being positioned above the first guide means;

at least two first wheeled traveling members secured to the underside of each of the second guide means, each of such first wheeled traveling members being positioned such that it is in contact with one of the first guide means and may move longitudinally along such first guide means;

a drive motor associated with at least one of such first wheel traveling members and operatively coupled to the wheel portion thereof for generating motive forces to revolve such wheel in a selected direction;

at least four second wheeled traveling members secured to the underside of the substructure, such second wheel traveling members being positioned such that at least two of such second wheeled traveling members are in contact with the upper surface of each of the second guide means and may move longitudinally along such second guide means;

a drive motor associated with at least one of such second wheeled traveling members and operatively coupled to the wheel portion thereof for generating motive forces to revolve such wheel in a selected direction;

the controlled operation of the drive motors and the associated wheeled traveling members providing relatively low lateral resistance to the movement of the platform as it moves horizontally underneath the positioned substructure responsive to the ice conditions.

3. In a platform from which subaqueous operations are performed in ice conditions, the platform having an aperture therethrough through which the subaqueous operations are performed and the platform carrying a substructure for supporting the equipment for performing the subaqueous operations, such substructure being positioned whereby it straddles the aperture and said substructure preferably remaining in a fixed lateral position with respect to the subaqueous operations being performed by the equipment supported by such substructure, the improved method of allowing the platform to move horizontally beneath the fixed position substructure responsive to the ice forces whereby the platform may move relative to the substructure and the substructure may remain in a fixed lateral position above the subaqueous operations being performed by the equipment carried by the substructure, including the steps of:

positioning between the underside of the substructure and the platform;

at least two first guide means in parallel relationship, one of such first guide means being positioned on either side of the aperture;

at least two second guide means in parallel relationship with each other, one of such second guide means being positioned on either side of the aperture, said second guide means being positioned above the first guide means, first wheeled traveling members secured beneath each of the second guide means and in contact with one of the first guide means for longitudinal movement therealong;

second wheeled traveling members secured beneath the underside of the substructure and in contact with the second guide members for longitudinal movement therealong;

drive motors associated with the wheel traveling members and operatively coupled thereto for generating motor forces to revolve the wheeled portion thereof; and

operating the drive motors whereby the traveling members move selected distances longitudinally along the first and second guide means and the platform is moved horizontally beneath the substructure responsive to ice conditions to maintain the substructure in a fixed position.