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US 10,309,178 B2Granted
Mills with shearable cutting members for milling casings in wellbores
AssigneeBaker Hughes, A Ge Company, LLC
InventorDaniel R. Hart
Life of this patent
Estimating the term…
Abstract
A mill for milling a casing in a wellbore. The mill includes a plurality of radially extendable cutting members on a body. An activation device extends the cutting members radially outward from the body upon application of a hydraulic pressure to the activation device and mechanically retracts the blades upon removal of the hydraulic pressure from the activation device. The cutting members are separable from the body.
Claims13
A mill, comprising:
- a plurality of radially extendable cutting members on a body, wherein the cutting members are separable from the body;
- an activation device including a piston that moves upward when a hydraulic pressure is applied on the activation device and moves downward when the hydraulic pressure is removed from activation device;
- a knife extension device at a lower end of the piston, wherein the knife extension device moves upward with upward movement of the piston to extend the cutting members radially outward from the body upon application of the hydraulic pressure to the activation device and moves downward with a downward movement of the piston upon removal of the hydraulic pressure from the activation device to allow the blades to mechanically retract;
- and
- a shear device that shears when a pull force applied to the mill exceeds a selected value to separate the cutting members from the body.
2 more elements
A method of milling a casing in a wellbore, the method comprising:
- conveying a string in the wellbore, the string having a mill that includes:
- a plurality of radially extendable cutting members on a body of the mill that are separable from the body, and
- an activation device including a piston that moves upward when a hydraulic pressure is applied on the activation device and moves downward when the hydraulic pressure is removed from activation device,
- a knife extension device at a lower end of the piston, wherein the knife extension device moves upward with upward movement of the piston to extend the cutting members radially outward from the body upon application of the hydraulic pressure to the activation device and moves downward with a downward movement of the piston upon removal of the hydraulic pressure from the activation device to allow the blades to mechanically retract;
- and
- a shear device that shears when a pull force applied to the mill exceeds a selected value to separate the cutting members from the body;
- applying the hydraulic pressure on the activation device to extend the cutting members to engage with the casing;
- and
- operating the mill while applying one of a pull force and a push force on the mill to mill the casing.
6 more elements
Dependencies are inferred from the claim text.