Method and apparatus for installing a sea-floor cellar in a subsea bottom having compacted soil conditions

Claim 1

A method of installing a sea-floor cellar in shallow water areas in order to position a blowout preventer stack substantially below the surface of the sea floor, which has a hard or compacted soil structure, comprising the steps of: drilling a first pattern of first bore holes in a configuration generally the same as the sea-floor cellar to be installed in order to produce a first honeycomb soil structure of substantially the same configuration and depth as the sea-floor cellar to be installed; drilling a second pattern of bore holes into said first honeycomb wherein each bore hole of said second pattern has a larger diameter than the bore holes in said first pattern thereby producing a second honeycomb soil structure; inserting a bar member into said second honeycomb of bore holes, and rotating said bar member therein to eliminate standing walls in said second honeycomb to produce a substantially cleared recessed area; utilizing fluid jetting action to further loosen and suspend said particles during and after use of said rotating bar member in said second honeycomb of holes to create a clear, recessed area having outer walls of a configuration and sufficient depth to receive said sea-floor cellar; and implanting such sea-floor cellar in said recess while simultaneously removing at least some of such suspended particulate.

Claim 2

A method of installing a sea-floor cellar in shallow water areas in order to position a blowout preventer stack substantially below the surface of the sea floor, which has a hard or compacted soil structure, comprising the steps of: drilling a first pattern of first bore holes in a configuration generally the same as the sea-floor cellar to be installed in order to produce a first honeycomb soil structure of substantially the same configuration and depth as the sea-floor cellar to be installed; drilling a second pattern of bore holes into said first honeycomb wherein each bore hole of said second pattern has a larger diameter than the bore holes in said first pattern thereby producing a second honeycomb soil structure; inserting a bar member into said second honeycomb of bore holes, and rotating said bar member therein to eliminate standing walls in said second honeycomb to produce a substantially cleared recessed area; utilizing fluid jetting action to further loosen and suspend said particles during and after use of said rotating bar member in said second honeycomb of holes to create a clear, recessed area having outer walls of a configuration and sufficient depth to receive said sea-floor cellar; and implanting such sea-floor cellar in said recess while simultaneously removing at least some of such suspended particulate.

Claim 9

A system for installing a sea-floor cellar substantially in the ocean floor in shallow water areas where the distance between the sea-floor, which has a packed or rock-ladened soil formation, and the drill ship is not sufficient to allow for normal positioning of a blowout preventer stack at the surface of the ocean floor, comprising: an inverted, conically shaped jetting tool adapted for attachment to such drill ship for insertion into a designated area of a soil formation, which area must be cleared in order to receive an implantable sea-floor cellar therein for housing a blowout preventer stacks substantially below the surface of the ocean floor; such first inverted conically shaped tool including a plurality of outwardly angled leg sections attached to a central post member whereby such leg sections break up the surrounding soil upon rotation of the central post member; a second T-shaped jetting tool adapted for attachment to such drill ship and for extension into a hole at least partially cleared by said first inverted, conically shaped jetting tool, said second jetting tool having a T-shape and including a lower, horizontal section attached at its center point to a vertical section adapted for attachment to such drill ship, said horizontal section being rotatable within said substantially clear recessed area in order to further clear such area of soil formation to receive said implantable sea-floor cellar; and a portable suction means adapted for lowering from said drill ship into said designated area to remove loose particulate produced from the rotative action of said first and second jetting tool.

Claim 10

A system for installing a sea-floor cellar substantially in the ocean floor in shallow water areas where the distance between the sea-floor, which has a packed or rock-ladened soil formation, and the drill ship is not sufficient to allow for normal positioning of a blowout preventer stack at the surface of the ocean floor, comprising: an inverted, conically shaped jetting tool adapted for attachment to such drill ship for insertion into a designated area of a soil formation, which area must be cleared in order to receive an implantable sea-floor cellar therein for housing a blowout preventer stacks substantially below the surface of the ocean floor; such first inverted conically shaped tool including a plurality of outwardly angled leg sections attached to a central post member whereby such leg sections break up the surrounding soil upon rotation of the central post member; a second T-shaped jetting tool adapted for attachment to such drill ship and for extension into a hole at least partially cleared by said first inverted, conically shaped jetting tool, said second jetting tool having a T-shape and including a lower, horizontal section attached at its center point to a vertical section adapted for attachment to such drill ship, said horizontal section being rotatable within said substantially clear recessed area in order to further clear such area of soil formation to receive said implantable sea-floor cellar; and a portable suction means adapted for lowering from said drill ship into said designated area to remove loose particulate produced from the rotative action of said first and second jetting tool.