Subsea foundation

Claim 2

A form for use on the bottom of a body of water for constructing an underwater foundation for offshore drilling or production equipment, comprising: a rigid outer structure surrounding a space having a fixed area; means for containing fill material in such space within said structure when said structure rests on such bottom of such body of water, said structure being sized to rest substantially completely below the surface of the water; and buoyancy means located on said structure for controlling the buoyancy of said structure, the location of said buoyancy means being such that the ends of said structure can be sequentially sunk to and raised from such bottom of such body of water; said rigid outer structure including means for lowering a section of said structure and for permitting the passage of such offshore equipment over said lowered section and into or out of said form; first and second sidewall members each having a front end and a rear end; first and second front wall members rigidly connected to the front ends of said first and second sidewall members, respectively, there being a passageway between said first and second front wall members; a front door member slidably pivotally connected to said first and second front wall members across said passageway; and a rear door member releasably connected to said first and second sidewall members at the rear ends thereof.

Claim 3

A form according to claim 4, said first and second sidewall members and said first and second front wall members including hollow tanks disposed therewithin, said buoyancy means including means for alternately flooding and emptying said tanks for controlling the buoyancy of said sidewall members and said front wall members to effect such sequential sinking and raising of said ends of said structure.

Claim 4

A form for use on the bottom of a body of water for constructing an underwater foundation for offshore drilling or production equipment, comprising: a rigid outer structure surrounding a space having a fixed area; means for containing fill material in such space within said structure when said structure rests on such bottom of such body of water, said structure being sized to rest substantially completely below the surface of the water; and buoyancy means located on said structure for controlling the buoyancy of said structure, said rigid outer structure including means for lowering a section of said structure and for permitting the passage of such offshore equipment over said section and into or out of said form, first and second sidewall members each having a front end and a rear end, first and second front wall members rigidly connected to the front ends of said first and second sidewall members, respectively, there being a passageway between said first and second front wall members, a front door member slidably pivotally connected to said first and second front wall members across said passageway, a rear door member forming said section of said structure releasably connected to said first and second sidewall members at the rear ends thereof, a bottom member connected to said sidewall members and said front wall members, said bottom member having a slot therein in communication with said passageway between said front wall members, said first and second sidewall members and said first and second front wall members including hollow tanks disposed therewithin, said buoyancy means including means for alternately flooding and emptying said tanks for controlling the buoyancy of said sidewall members and said front wall members.

Claim 5

A form for use on the bottom of a body of water for constructing an underwater foundation for offshore drilling or production equipment, comprising: a rigid outer structure surrounding a space having a fixed area; means for containing fill material in such space within said structure when said structure rests on such bottom of such body of water, said structure being sized to rest substantially completely below the surface of the water; and buoyancy means located on said structure for controlling the buoyancy of said structure, said rigid outer structure including means for lowering a section of said structure and for permitting the passage of such offshore equipment over said section and into or out of said form, first and second sidewall members each having a front end and a rear end, first and second front wall members rigidly connected to the front ends of said first and second sidewall members, respectively, there being a passageway between said first and second front wall members, a front door member slidably pivotally connected to said first and second front wall members across said passageway, a rear door member forming said section of said structure releasably connected to said first and second sidewall members at the rear ends thereof, a bottom member connected to said sidewall members and said front wall members, said bottom member having a slot therein in communication with said passageway between said front wall members, said first and second sidewall members and said first and second front wall members including hollow tanks disposed therewithin, said buoyancy means including means for alternately flooding and emptying said tanks for controlling the buoyancy of said sidewall members and said front wall members.

Claim 6

A form according to claim 4, further including a downwardly extending skirt connected to the bottom of said rigid outer structure around the perimeter thereof.