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

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.