Abstract: A milling tool which includes a nose cutting portion, a cutting section having a plurality of hardened cutters and a shaft portion. A wear pad is disposed on the cutting section and shaft portion. Upon the shaft portion, the wear pad extends radially outwardly to an engagement diameter that exceeds the maximum cutting diameter of the cutters.

Abstract: A milling tool which includes a nose cutting portion, a cutting section having a plurality of hardened cutters and a shaft portion. A wear pad is disposed on the cutting section and shaft portion. Upon the shaft portion, the wear pad extends radially outwardly to an engagement diameter that exceeds the maximum cutting diameter of the cutters.

Abstract: An apparatus for cutting a window in a casing pipe in a well, having only a single mill with full gage primary cutting inserts of a very hard, highly wear resistant, material. The primary inserts can be protected from damage by forming each blade on the mill with an outside edge profile having a shallower angle than the angle of the whipstock which is used to guide the mill through the casing, preventing the primary inserts from riding directly on the whipstock. The primary inserts on each blade can be further protected from damage by a row of secondary inserts of a relatively more durable material, arranged behind each row of primary inserts, or by a full diameter buffer section of mill body or blade.

Abstract: Improved cutter design as well as an improved design for downhole cutters, such as mandrel cutters and rotary cutter mills. A cutter is described with a rectangular, rounded “lozenge” shape. The cutter presents a cross-sectional cutting area having a pair of curvilinear end sections and an elongated central section. Preferably, the overall length of the cutter is 1.5 times the width. The cutter may also include a raised cutter edge for chip breaking during cutting.

Abstract: Improved cutter design as well as an improved design for downhole cutters, such as mandrel cutters and rotary cutter mills. A cutter is described with a rectangular, rounded “lozenge” shape. The cutter presents a cross-sectional cutting area having a pair of curvilinear end sections and an elongated central section. Preferably, the overall length of the cutter is 1.5 times the width. The cutter may also include a raised cutter edge for chip breaking during cutting.

Abstract: An assembly for milling a window in a tubular features a layout that keeps a restorative force normal to the whipstock slope acting on the window mill to help it track the whipstock ramp long enough for making an exit at the desired location. A string mill assembly is made long enough to allow such a restorative force to be created on the window mill as it advances down the ramp. The bearing or cutting structures on the string mill are positioned with respect to the window mill so that either the top of the string mill or at least the first bearing structure above the window mill presents at the top of the window as the window mill arrives at the position where it is desired that it make an exit. The lower bearing structure of the string mill also preferably has a rounded profile to facilitate its entrance on to the whipstock ramp without getting in a bind on the tubular wall adjacent the top of the window.

Abstract: A method and apparatus for running a whipstock into a well bore attached to a combination mill and drill bit, releasing the mill/bit from the whipstock, milling a window in the casing, and drilling a lateral well bore, all in one trip. The mill/bit is provided with a primary cutting structure better suited for milling through the casing, and a secondary cutting structure, better suited for drilling through the earth formation. The secondary cutting structure is initially smaller in diameter than the primary cutting structure. The whipstock can be attached to the mill/bit with a shear bolt supported by a boss on the whipstock, with the boss designed to arrest axial motion of the mill/bit after shearing of the bolt.

Abstract: An improved whipstock design features a ramp having a lower terminus at the location of the expected window bottom. The lower end of the whipstock ramp transitions gradually from a preferably flat guide surface to a more drastic exit orientation that is preferably obtained by going to an arcuate exit of a rather large radius to present a smooth transition from the flat guide surface to an orientation that allows kick-out to occur by the end of the ramp. This in turn allows the ramp end to closely approximate the window bottom to reduce the risk of creation of a pocket near the window bottom that could trap or damage equipment delivered in subsequent runs.

Abstract: Devices and methods for releasably securing components of a device having a sliding sleeve arrangement to prevent premature actuation due to vibration. In a currently preferred embodiment, the invention utilizes standard elastomeric O-rings as shear members. The O-ring shear members reside within spaces formed between two slidable sleeve members. The O-rings are sheared cross-sectionally to allow the sleeve members to move axially with respect to one another. An exemplary coiled tubing shear release joint is described that incorporates a shear disconnect assembly which uses elastomeric O-rings as shear members. Multiple O-ring seals can be used as shear members to increase the shear value of the device. The use of O-rings as shear members helps prevent premature sliding of sleeve components in response to high vibration. Because the O-rings are resilient, they absorb vibration and do not shear during vibration, the connection between the two sleeve components will not be released prematurely.

Abstract: A method of downhole milling of an item having high chrome/high nickel content, using polycrystalline diamond cutting elements, exhibiting less wear, requiring less torque and weight, and producing less heat, than prior art tungsten carbide elements.

Abstract: An apparatus for cutting a window in a casing pipe in a well, having only a single mill with full gage primary cutting inserts of a very hard, highly wear resistant, material. The primary inserts can be protected from damage by forming each blade on the mill with an outside edge profile having a shallower angle than the angle of the whipstock which is used to guide the mill through the casing, preventing the primary inserts from riding directly on the whipstock. The primary inserts on each blade can be further protected from damage by a row of secondary inserts of a relatively more durable material, arranged behind each row of primary inserts, or by a full diameter buffer section of mill body or blade.

Abstract: A cutting insert for use on a metal cutting tool downhole in an oil or gas well, with at least one land on a leading edge of the insert, and at least one bevel surface angled relative to the axis of the insert and rising above the adjacent land in the direction of travel of the insert. Multiple bevels and lands can be used on each insert, and multiple inserts can be used on each tool.

Abstract: A method and apparatus for running a whipstock into a well bore attached to a combination mill and drill bit, releasing the mill/bit from the whipstock, milling a window in the casing, and drilling a lateral well bore, all in one trip. The mill/bit is provided with a primary cutting structure better suited for milling through the casing, and a secondary cutting structure, better suited for drilling through the earth formation. The secondary cutting structure is initially smaller in diameter than the primary cutting structure. The whipstock can be attached to the mill/bit with a shear bolt supported by a boss on the whipstock, with the boss designed to arrest axial motion of the mill/bit after shearing of the bolt.