Method for forming an underground cavity
OwnerRichard A. Wallersinventor
Life of this patent
Estimating the term…
Abstract
A caisson and connecting conductor pipe sections are lowered to a predetermined position on the ocean underwater floor. A drill stem having a combined drilling and reaming tool is positioned within the conductor pipe and caisson. Drilling mud is reversed-circulated through the annular space between the conductor pipe and caisson and the drill stem, the drilling mud returning through the drill stem. The tool mounted on the drill stem is utilized to drill to a predetermined depth whereupon one or more reaming arms open outward from the tool and are rotated, thereby cutting out a volume of the ocean floor within which the caisson may be positioned.
Claims12
A method for placing an offshore caisson comprising:
- connecting at least one conductor section to said caisson, said conductor having a cross-sectional area less than the cross-sectional area of said caisson;
- lowering said caisson and said conductor section to a predetermined position on the underwater floor;
- positioning a drill stem having a combined drilling and reaming tool attached thereto within said conductor section and said caisson;
- reverse-circulating a drilling mud through the annular space between said connected conductor section and caisson and said drill stem, said drilling mud returning through said drill stem;
- drilling with said drilling and reaming tool to a predetermined depth;
- opening and rotating at least one reaming arm of said drilling and reaming tool;
- and
- positioning said caisson within the area drilled and reamed by said drilling and reaming tool.
A method for placing an offshore caisson comprising:
- connecting at least one conductor section to said caisson, said conductor having a cross-sectional area less than the cross-sectional area of said caisson;
- lowering said caisson and said conductor section to a predetermined position of the underwater floor;
- positioning a drill stem having a combined drilling and upreaming tool attached thereto within said conductor section and said caisson;
- reverse-circulating a drilling mud through the annular space between said joined conductor section and caisson and said drill stem, said drilling mud returning through said drilling and upreaming tool and said drill stem;
- drilling with said drilling tool to a predetermined depth;
- opening and rotating at least one reaming arm of said upreaming tool;
- positioning said caisson within the area drilled and reamed by said drilling and belling tool;
- removing said drill stem and drilling and upreaming tool from said caisson and disconnecting said conductor section from said caisson.
A caisson placing device comprising:
- a caisson;
- a drill stem having a combined drilling and reaming tool;
- at least one conductor section connected to said caisson, said conductor section having a cross-sectional area which is substantially less than the cross-sectional area of the caisson, and being adapted to receive said drill stem having a combined drilling and reaming tool;
- reverse-circulating drilling mud means for reverse circulating drilling mud through the annular space between said joined conductor section and said caisson and said drilling stem, said reverse-circulating drilling mud means being adapted to return said drilling mud through said drill stem.
Dependencies are inferred from the claim text.