Method and apparatus for severing well casing in a submarine environment

Claim 1

THE METHOD OF CUTTING A WELL CASING OF THE TYPE WHICH INCLUDES A PLURALITY OF TELESCOPED CASING STRINGS, SAID METHOD COMPRISING: (A) SUSPENDING AT A FIXED, PRESELECTED POINT IN THE INNERMOST OF SAID CASING STRINGS, A CUTTING TOOL HAVING PIVOTALLY SECURED THERETO AT LEAST ONE ELONGATED CUTTING MEMBER OF A PRESELECTED LENGTH CORRELATED IN LENGTH TO THE DIAMETER OF THE INNERMOST OF SAID TELESCOPED CASING STRINGS TO PROVIDE EFFICIENT CUTTING OF SAID CUTTING MEMBER THROUGH SAID INNERMOST CASING STRING; (B) PIVOTING SAID ELONGATED CUTTING MEMBER TO A POSITION IN WHICH THE CUTTING MEMBER CONTACT THE INTERNAL WALL OF SAID INNERMOST CASING STRING; (C) ROTATING THE CUTTING TOOL TO CAUSE SAID ELONGATED CUTTING MEMBER TO CUT THROUGH SAID INNERMOST CASING STRING THROUGH ITS ENTIRE CIRCUMFERENCE AND TO FORM AN AXIALLY EXTENDING OPENING THROUGH SAID INNERMOST CASING STRING; THEN (D) PIVOTALLY SECURING TO SAID CUTTING TOOL, AT LEAST ONE OTHER ELONGATED CUTTING MEMBER HAVING A PRESELECTED LENGTH WHICH IS GREATER THAN THE LENGTH OF SAID FIRSTMENTIONED CUTTING MEMBER; (E) POSITIONING SAID CUTTING TOOL IN SAID INNERMOST CASING STRING AT A PRESELECTED POINT ABOVE SAID FIRST-MENTIONED PRESELECTED POINT AND SELECTED TO PERMIT SAID OTHER CUTTING MEMBER TO EXTEND UPON PIVOTATION THROUGH THE AXIALLY EXTENDING OPENING FORMED IN SAID INNERMOST TELESCOPED CASING STRING BY SAID FIRST-MENTIONED CUTTING MEMBER; (F) PIVOTING SAID OTHER CUTTING MEMBER THROUGH THE AXIALLY EXTENDING OPENING FORMED IN SAID INNERMOST CASING STRING BY SAID FIRST MENTIONED ELONGATED CUTTING MEMBER; AND (G) ROTATING THE CUTTING TOOL TO CAUSE SAID OTHER CUTTING MEMBER TO CUT THROUGH AT LEAST ONE OF THE CASING STRINGS WHICH SURROUNDS SAID INNERMOST CASING STRING.

Claim 2

THE METHOD OF CUTTING A WELL CASING OF THE TYPE WHICH INCLUDES A PLURALITY OF TELESCOPED CASING STRINGS, SAID METHOD COMPRISING: (A) SUSPENDING AT A FIXED, PRESELECTED POINT IN THE INNERMOST OF SAID CASING STRINGS, A CUTTING TOOL HAVING PIVOTALLY SECURED THERETO AT LEAST ONE ELONGATED CUTTING MEMBER OF A PRESELECTED LENGTH CORRELATED IN LENGTH TO THE DIAMETER OF THE INNERMOST OF SAID TELESCOPED CASING STRINGS TO PROVIDE EFFICIENT CUTTING OF SAID CUTTING MEMBER THROUGH SAID INNERMOST CASING STRING; (B) PIVOTING SAID ELONGATED CUTTING MEMBER TO A POSITION IN WHICH THE CUTTING MEMBER CONTACT THE INTERNAL WALL OF SAID INNERMOST CASING STRING; (C) ROTATING THE CUTTING TOOL TO CAUSE SAID ELONGATED CUTTING MEMBER TO CUT THROUGH SAID INNERMOST CASING STRING THROUGH ITS ENTIRE CIRCUMFERENCE AND TO FORM AN AXIALLY EXTENDING OPENING THROUGH SAID INNERMOST CASING STRING; THEN (D) PIVOTALLY SECURING TO SAID CUTTING TOOL, AT LEAST ONE OTHER ELONGATED CUTTING MEMBER HAVING A PRESELECTED LENGTH WHICH IS GREATER THAN THE LENGTH OF SAID FIRSTMENTIONED CUTTING MEMBER; (E) POSITIONING SAID CUTTING TOOL IN SAID INNERMOST CASING STRING AT A PRESELECTED POINT ABOVE SAID FIRST-MENTIONED PRESELECTED POINT AND SELECTED TO PERMIT SAID OTHER CUTTING MEMBER TO EXTEND UPON PIVOTATION THROUGH THE AXIALLY EXTENDING OPENING FORMED IN SAID INNERMOST TELESCOPED CASING STRING BY SAID FIRST-MENTIONED CUTTING MEMBER; (F) PIVOTING SAID OTHER CUTTING MEMBER THROUGH THE AXIALLY EXTENDING OPENING FORMED IN SAID INNERMOST CASING STRING BY SAID FIRST MENTIONED ELONGATED CUTTING MEMBER; AND (G) ROTATING THE CUTTING TOOL TO CAUSE SAID OTHER CUTTING MEMBER TO CUT THROUGH AT LEAST ONE OF THE CASING STRINGS WHICH SURROUNDS SAID INNERMOST CASING STRING.