Abstract: A one-trip, window-milling system method and apparatus is disclosed. The system is particularly useful in thru-tubing applications where the mills are run on coiled tubing in conjunction with a downhole motor. Preferably, the whipstock is run through tubing and set in position. The mill assembly is typically run in after the thru-tubing whipstock is oriented and set. The mill assembly is supported by a downhole motor, which is in turn run-in with coiled tubing. The pilot mill or leading mill is of a particular shape so as to minimize its torque requirements for initiating the window. A wear device, which acts as a guide, is located behind the initial mill and acts with a flexible connector above the subsequent mills in orienting the initial mill into the casing and away from the whipstock. The subsequent mill or mills feature a gradual increase in cross-sectional area along its or their length, also minimizing the required torque for the downhole motor.

Abstract: A support mechanism for a mill, particularly usable with a whipstock and driven by a downhole motor supported by coiled tubing is disclosed. The support mechanism comprises a wearable ring adjacent the cutting structure which, when assembled into the downhole assembly, keeps the rotating blades away from the whipstock face and oriented toward the casing to be cut. As the milling progresses, the support mechanism wears away to allow advancement of the mill into the casing to complete the formation of the window or opening.

Abstract: A one-piece flapper mount for a wireline retrievable hydraulic piston actuated wrap-around flapper safety valve. The flapper mount has opposing openings between the valve seat and the nose seal and the openings are sized for insertion of the flapper valve and nose seal with support ribs between the openings. The single piece construction allows setting and retrieving the safety valve in a single trip. The one-piece mount also has the advantage of ease of orientation of coacting parts.