Expandable window milling bit and methods of milling a window in casing

摘要

A method of milling a window through a casing in a primary well bore and drilling a sidetracked well bore into a formation including running a drilling assembly including a body having an axis defined therethrough, a piston that is movable within a cavity formed in the body, a stationary cutting structure coupled to the body, and a movable cutting structure coupled to the body, milling a window through the casing in a first trip into the primary well bore, drilling the sidetracked well bore in the first trip into the primary well bore, applying a differential pressure across the piston, and moving the movable cutting structure from the collapsed position to the expanded position. The movable cutting structure is coupled to the piston and is movable between a collapsed position and an expanded position.

主权项

1. A method of milling a window through a casing in a primary well bore and drilling a sidetracked well bore into a formation comprising:
running a drilling assembly including a body having an axis defined therethrough and a track formed thereon, a piston that is movable within a cavity formed in the body, a stationary cutting structure coupled to the body, and a movable cutting structure coupled to the body, wherein the movable cutting structure is coupled to the piston via a link and is slidingly engaged with the track formed on the body and is movable along the track between a collapsed position and an expanded position; milling a window through the casing in a first trip into the primary well bore; drilling the sidetracked well bore in the first trip into the primary well bore; applying a differential pressure across a lower end of the piston; retracting the movable piston disposed in the cavity formed in the body of the drilling assembly from a downstream position to an upstream position; and moving the movable cutting structure along the track from the collapsed position to the expanded position via the link during the retracting of the movable piston.