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US 10,240,418 B2Granted
Apparatus and method for inner casing string window milling and outer casing cement sheath removal
AssigneeAbrado, Inc.
InventorDavid J. Ruttley
Life of this patent
Estimating the term…
Abstract
A casing mill having a main body with cutter bases with cutters mounted on the cutter bases. The cutter bases are moved radially by operating arms which are rotatably attached to the main body, which are in turn moved by an operating mechanism in response to fluid flow through. One or more of the operating arms are extended to form a cutout arm, which enables cutting an initial window in a casing string, from which milling can continue. The operating arms are mounted to the main body by pins, which are held in the main body by a pin retaining arrangement.
Claims9
A casing mill adapted for placement in a drillstring, comprising:
- an elongated main body having a bore;
- a plurality of elongated cutter bases hingedly connected to said main body by a plurality of operating arms and movable between a first position substantially retracted to said main body, and a second position extended outwardly from said main body;
- one or more cutters mounted on each of said cutter bases, said cutters positioned so as to be in cutting relationship with a casing string when said cutter bases are in said second position;
- wherein each of said cutter bases comprises a stabilizer section on a lower end thereof, wherein no cutters are mounted, said stabilizer section adapted to bear against an inner wall of a casing string when said cutter bases are in said second position;
- a radial dimension of said cutters extending outwardly from said cutter base and beyond an outer diameter of said casing string, when said stabilizer bears against said inner wall of said casing string, a sufficient distance to extend over any casing collar on said casing, and wherein a radial outward face of said cutter comprises a non-cutting surface;
- wherein one or more of said operating arms comprises an extended cutout arm which extends beyond the radial outermost position of said cutters when said cutter bases are in said second position, so that an outer end of said cutout arm contacts said inner wall of said casing string while said cutters are not in contact with said inner wall, said cutout arm comprising a hardened cutting surface to enable cutting through said casing;
- and
- a means for moving said cutter bases between said first and second positions.
5 more elements
A method for milling sections of a casing string, comprising the steps of:
- a. providing a casing mill adapted for placement in a drillstring, comprising:
- an elongated main body having a bore;
- a plurality of elongated cutter bases hingedly connected to said main body by a plurality of operating arms and movable between a first position substantially retracted to said main body, and a second position extended outwardly from said main body;
- one or more cutters mounted on each of said cutter bases, said cutters positioned so as to be in cutting relationship with a casing string when said cutter bases are in said second position, said cutters at least partially covered in a hardened cutting material;
- wherein each of said cutter bases comprises a stabilizer section on a lower end thereof, wherein no cutters are mounted, said stabilizer section adapted to bear against an inner wall of a casing string when said cutter bases are in said second position;
- a radial dimension of said cutters extending outwardly from said cutter base and beyond an outer diameter of said casing string, when said stabilizer bears against said inner wall of said casing string, a sufficient distance to extend over any casing collar on said casing, and wherein a radial outward face of said cutter comprises a non-cutting surface;
- wherein one or more of said operating arms comprises an extended cutout arm which extends beyond the radial outermost position of said cutters when said cutter bases are in said second position, so that an outer end of said cutout arm contacts said inner wall of said casing string while said cutters are not in contact with said inner wall, said cutout arm comprising a hardened cutting surface to enable cutting through said casing;
- and
- a means for moving said cutter bases between said first and second positions, said means for moving responsive to fluid pumped through said main body;
- b. lowering said casing mill on a drillstring into a wellbore to a desired position within said wellbore;
- c. pumping fluid through said drillstring and said main body, thereby causing said means for moving said cutter bases between said first and second positions to move said operating arms and said cutter bases outwardly until said cutout arm contacts said casing;
- d. rotating said casing mill while continuing pumping fluid therethrough, whereby said cutout arms cut through said casing string and creating an upward facing casing edge;
- e. rotating and lowering said casing mill to engage said cutout arms on said upward facing casing edge with a desired weight, while continuing pumping fluid therethrough, and cutting a window of sufficient length in said casing;
- f. increasing rotation speed and weight on said casing mill so as to wear away said cutout arms to a radial dimension small enough for said cutout arms to enter said casing string;
- g. rotating and lowering said casing mill to engage said cutters on said upward facing casing edge with a desired weight, while continuing pumping fluid therethrough, until a desired window length has been cut.
12 more elements
Dependencies are inferred from the claim text.