Baker Hughes Corporation

Andy Ferguson

Edgar D Lueders

Randy Reich

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. The system is capable of penetrating thick casing such as standard weight 7' casing in approximately 3 hours or less.

One-trip, thru-tubing, window-milling system

The present invention provides a disconnect which has the internal integrity to make it as strong as the rest of the drill string. The present invention can disconnect when desired, despite the fact that the apparatus is at that time subjected to significant tensile or compressive loads. The invention allows for disconnection by alternative methods. Accordingly, in one version of the tool, a ball can be dropped or pumped to a seat to facilitate disconnection. In another version of the tool, that may employ an internal wireline precluding the use of a ball, disconnection can be accomplished by compression of a stack of Bellville washers, in response to a tensile force, to release a collet-locking mechanism. Either design features a rotational locking component.

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Spring, TX, United States of America

Andy Ferguson