| 主权项 |
1. A section mill for removing a portion of a casing in a wellbore, comprising:
a body having a first end portion, a second end portion, and a bore formed axially therethrough; a plurality of blades each having a first end portion and a second end portion, wherein the first end portion of each blade is movably coupled to the body, and the second end portion of each blade has a cutting surface disposed thereon; at least two pistons within the bore of the body, a first of the at least two pistons being axially between the second of the at least two pistons and the second end portion of the body; a cam coupled to the second of the at least two pistons and adapted to be moved axially within the bore of the body by the second of the at least two pistons; and a seat formed within the bore and coupled to the first of the at least two pistons, the seat being axially between the second end portions of the plurality of blades and the second end portion of the body, wherein the plurality of blades are adapted to actuate from an inactive position to an active position in response to the cam moving axially within the bore and engaging the plurality of blades, the cam being movable in response to a fluid pressure increase moving the second of the at least two pistons in response to an impediment entering the body through the first end portion, moving axially past the second of the at least two pistons, and forming a seal against the seat, the plurality of blades being adapted to actuate to the active position while the impediment remains seated on the seat. |
