Milling tool and method for milling multiple casing strings
AssigneeBaker Hughes Incorporated
InventorsTerry E. Cassel, Harold E. Payne, Gerald D. Lynde
Life of this patent
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Abstract
A cutting tool (22) includes a plurality of pivoted blades (36) for swinging outwardly to an expanded radial position for first cutting the walls of multiple casing strings (10, 11), and then removing a predetermined length of the casing strings (10, 11) simultaneously in a cutting action. Pivoted blades (36) have cutting elements (66) of a similar size and shape positioned about upper, lower, and outer sides (60, 62, 64) of the blades (36). The lower sides (62) of the blades (36) engage the upper annular cut ends of the casing strings (10, 11) in a cutting action without tripping or removal from the bore hole.
Claims21
A method of cutting through the walls of a pair of generally concentric inner and outer casings and then simultaneously removing a predetermined length of said inner and outer casings;
- said method comprising the following steps:
- providing a cutting tool having pivotally mounted blades adapted for swinging outwardly in a generally radial direction from a tool body received within a casing;
- providing a plurality of hard cutting elements of a predetermined shape and size on selected areas along the outer periphery of said blades including the upper and lower sides and the outer ends of said blades when pivoted radially outwardly;
- positioning said cutting tool within said inner casing;
- rotating said tool at a predetermined rotational speed with said blades expanded radially outwardly into cutting engagement with the inner periphery of said inner casing;
- first cutting through the wall of said inner casing with the outer ends of said blades engaging the inner periphery of said inner casing in cutting relation;
- then cutting through the wall of said outer casing with the cutting elements on the outer ends of said blades engaging the inner periphery of said outer casing in cutting relation;
- and
- next engaging simultaneously the upper annular cut ends of both said inner and outer concentric casings in a cutting action by the cutting elements on the lower sides of said blades resulting from downward movement of said tool for removing a predetermined length of said casings.
A cutting tool mounted for rotation within a well for cutting through the walls of a pair of generally concentric inner and outer casings in the well and then removing simultaneously a predetermined length of said casing;
- said tool comprising:
- a tubular tool body received within the inner casing and adapted to receive drilling fluid from a connected drill string for discharge from its lower end;
- and
- a plurality of elongate cutting blades mounted on said body for outward swinging movement in a generally radial direction to an expanded position upon rotation of said cutting tool for initially engaging the inner peripheries of said casing in cutting relation for cutting through the walls of said inner and outer casings;
- said cutting blades having hard cutting elements of a predetermined shape and size in rows defining upper and lower cutting surfaces in an expanded position of the blades, and after cutting through the walls of said casings swinging outward to a further expanded position with said lower cutting surfaces of said blades engaging simultaneously the upper annular cut ends of said casings for removing a predetermined length of said casings as the tool moves downwardly.
A cutting tool mounted for rotation within a well for cutting through the wall of a casing in the well and then removing a predetermined length of said casing;
- said tool comprising:
- a tubular tool body received within said casing and adapted to receive drilling fluid from a connected drill string for discharge from its lower end;
- a plurality of elongate cutting blades mounted on said body for outward swinging movement in a generally radial direction to an expanded position upon rotation of said cutting tool and having upper and lower sides in cutting position;
- and
- a plurality of cutting elements of a predetermined size and shape secured in a side by side relation along said upper and lower sides of said blades in expanded cutting position thereof to form upper and lower rows of cutting elements;
- said cutting elements on said upper sides of said blades first engaging the inner periphery of said casing for cutting through the wall of said casing, said cutting elements on said lower sides of said blades engaging the upper annular cut end of said casing in a cutting action for removal of a predetermined length of said casing upon downward movement of said tool.
Dependencies are inferred from the claim text.