Abstract: The present invention generally relates to a cutting insert for use with wellbore milling tools. The cutting insert forms an angle between a milling surface of the insert and a surface of the tool that the insert is attached to in order to provide the proper cutting incline, and substantially perpendicular sides of the insert relative to the milling surface of the insert provide continuous support for the milling surface. In addition, the inserts can comprise spacers and legs that evenly distribute bonds formed between inserts and bonds formed between the inserts and the surface of the tool, respectively. Selecting the dimensions of the spacers and legs alters the strength of the bonds.

Abstract: The present invention generally relates to a cutting insert for use with wellbore milling tools. The cutting insert forms an angle between a milling surface of the insert and a surface of the tool that the insert is attached to in order to provide the proper cutting incline, and substantially perpendicular sides of the insert relative to the milling surface of the insert provide continuous support for the milling surface. In addition, the inserts can comprise spacers and legs that evenly distribute bonds formed between inserts and bonds formed between the inserts and the surface of the tool, respectively. Selecting the dimensions of the spacers and legs alters the strength of the bonds.

Abstract: The present invention generally provides an apparatus and method for forming a pilot hole in a formation. In one aspect of the present invention, the apparatus may comprise a starter mill connected to a bearing mill by a body joint. The apparatus may further comprise a lead bearing connected to a starter mill by a lead joint. Preferably, an outer diameter of the bearing mill is about the same as an inner diameter of a wellbore. As the lead bearing travels along the concave, the apparatus will bend between the bearing mill and the lead bearing. The bend urges the starter mill into contact with the wellbore wall. In another aspect of the present invention, a method for forming a pilot hole in a wellbore includes running a tool into the wellbore, the tool comprising a starter mill disposed between a first bearing and a second bearing. While running the tool along a concave of a whipstock, the tool bends between the first and second bearing and urges the starter mill to form the pilot hole.

Abstract: The present invention generally provides an apparatus and method for forming a pilot hole in a formation. In one aspect of the present invention, the apparatus may comprise a starter mill connected to a bearing mill by a body joint. The apparatus may further comprise a lead bearing connected to a starter mill by a lead joint. Preferably, an outer diameter of the bearing mill is about the same as an inner diameter of a wellbore. As the lead bearing travels along the concave, the apparatus will bend between the bearing mill and the lead bearing. The bend urges the starter mill into contact with the wellbore wall. In another aspect of the present invention, a method for forming a pilot hole in a wellbore includes running a tool into the wellbore, the tool comprising a starter mill disposed between a first bearing and a second bearing. While running the tool along a concave of a whipstock, the tool bends between the first and second bearing and urges the starter mill to form the pilot hole.

Abstract: A system has been invented for cutting wellbore casing and retrieving casing and a wellbore device connected thereto, the system, in one aspect, including engaging apparatus for releasably holding the wellbore device, casing cutting apparatus interconnected with and below the engaging apparatus for cutting casing in a wellbore, the wellbore device connected to the casing, and locking apparatus for selectively and releasably locking the engaging apparatus holding the wellbore device. In one aspect the engaging apparatus has one or more movable latching arms for releasably holding a wellbore device, e.g. but not limited to a wellhead and the arms are mounted below a top bonnet that holes therethrough so that the flushing of debris and/or cutting from the tops of the arms is facilitated. In one aspect, a drain sub is used to reduce flow to the casing cutter so that the circulation of debris and/or cuttings is inhibited.

Abstract: An array of cutting inserts has been invented having a plurality of adjacent inserts, each insert comprising a body having a top surface, a bottom, and a base, and a plurality of spaced-apart chipbreaking indentations in the top surface of the body, and a strengthening ridge between adjacent indentations of the plurality of spaced-apart chipbreaking indentations, and a peripheral strengthening ridge around an outer edge of the top surface of the body surrounding the plurality of spaced-apart chipbreaking indentations.

Abstract: New systems and methods have been invented for explosively forming openings, ledges, windows, holes, and lateral bores through tubulars such as casing, which openings may, in cerain aspects, extend beyond the casing into a formation through which a wellbore extends. In certain aspects openings (e.g. ledges, initial, or completed windows) in wellbore tubulars (e.g. tubing or casing) are made using metal oxidizing systems, water jet systems, or mills with abrasive and/or erosive streams flowing therethrough and/or therefrom.

Abstract: A wellbore sidetracking method has been invented which includes, in certain embodiments, milling out a casing section from a cased, cemented wellbore; placing a deflection device, e.g. a whipstock, so that, upon pivoting of the upper concave portion of the whipstock at least a top portion thereof extends up into and abuts casing above the milled out section and, in certain aspects, a portion of the whipstock also extends down into and abuts casing below the milled out section; introducing a mill into the wellbore to mill out a part of the casing above the milled out section which would interfere with the introduction of a drill bit; removing the mill; introducing a drilling system into the wellbore to be deflected into the milled out area; and drilling a new sidetracked bore with the drilling system from the milled out area. In one aspect a mill is provided which mills out the part of the casing above the milled out area without contacting the formation or with only minimal contact thereof.

Abstract: An apparatus is established which facilitates the cutting and removal of well casing on a single trip into the wellbore. The apparatus is run into the wellbore on the tubing string and provides a rotatable sleeve including grapples adapted to engage the casing, and to facilitate removal of the casing. The apparatus also includes cutting assemblies coupled to the mandrel, which may be rotated so as to cut the casing, thereby facilitating removal of the casing through use of the grapples.

Abstract: This miling tool for underground work consists of a tool body which has a plurality of cutter blades. Each cutter blade has a negative axial rake and an essentially constant negative radial rake. In addition, each cutter arm has a close packing of cylindrical cutting grade tungsten carbide inserts set at a lead angle of about 0 to 10 degrees. The inserts are also preferably vertically offset on adjacent cutting blades.