INTERMETALLIC BONDED DIAMOND (IBD) CUTTING ELEMENTS

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 U. S. C. § 119 (e) of U.S. Provisional Application No. 60/883,884, entitled "Intermetallic Bonded Diamond (IBD) Cutting Elements," filed January 8, 2007.

TECHNICAL FIELD

The present invention is related to cutting elements, and more particularly, to intermetallic bonded diamond (IBD) cutting elements having various shapes and configurations.

BACKGROUND OF THE INVENTION

Polycrystalline Diamond Compact (PDC) cutters have become the industry standard for oil and gas drilling, especially in soft, medium soft and medium formation types, IADC codes 1,4,5, and 6 type rock. Since the early days of PDC cutter and drill bit development commencing in the mid 1970' s cutter makers and bit designers have proposed complex cutter shapes that could preferentially shear adjacent portions of a target formation and/or guide movement of cuttings or sheared formation materials in a way that would enhance bit cleaning.

Examples of such shapes can be found in US Patent 4,660,659 and US Patent 4,538,690 to Short, Jr. and US Patent 4,593,777 and US Patent 4,558,753 to Barr. These

patents discuss diamond layer configurations of a curved, concave geometry for PDC cutters.

US Patent 4,570,726 to Hall describes a curved PDC drag element with a complex plowing configuration. US Patent 4,883,132 to Tibbitts discloses conventional "flat faced" PDC cutters in conjunction with a body design that carries large void areas in the bit blades. The concept was to allow for reverse jetting of shale cuttings through the blade. As a commercial reality, none of the more radical or complex cutter designs have found success primarily due to the difficulties attendant in actually manufacturing such cutters in high pressure diamond presses. If a cutter design could be manufactured but left high residual stresses in the PDC layer or in the tungsten carbide (WC) substrate, then the cutter would lack fracture toughness in field applications.

For a brief period in the 1990' s it was thought that Carbon Vapor Deposition (CVD) Diamond would overcome the difficulties with complex geometry attendant to PDC. However, it was found that the application of a thick and truly wear resistant layer associated with CVD is extremely time intensive and costly.

A more recent development, Intermetallic Bonded Diamond (IBD), is discussed in US Patent Application Publication 2006/0280638 published on December 14, 2006 and International Publication Number WO 2006/107628 published by WIPO on October 12 ^th , 2006.

Both of these patent applications are incorporated by reference for all purposes. There are examples in the prior art literature of specially configured PDC blades being deployed in the very center of Fixed Cutter bits to

improve the drilling characteristics of this slow surface speed area of the bit face.

SUMMARY OF THE DISCLOSURE

In accordance with teachings of the present disclosure, a cutting element may include a substrate having a bonding interface region and an intermetallic bonded diamond (IBD) element bonded to the bonding interface region of the substrate. In some embodiments, the bonding interface region of the substrate may have a non-axi-symmetrical shape and/or may be symmetrical about only one plane or about zero planes. In some embodiments, the bonding interface region of the substrate may have a shape of a tube, a beveled tube, a tube with one or more internal support structures, a scoop, a plow, a concave shape, a honeycombed shape, or other irregular or complex shape.

One aspect of the present disclosure may include forming cutting elements and/or inserts for fixed cutter drill bit with configurations that were previously difficult and sometimes not even possible to manufacture. One of the benefits of the present disclosure may include forming cutting elements with such configurations and the ability to survive repeated impact loads associated with drilling deep, high pressure and/or high temperature wellbores.

Forming cutting elements or inserts with an axial bore extending through each cutting element or insert may allow enhanced penetration of an adjacent formation and enhanced removal of formation materials from the bottom of a wellbore. Forming an axial bore in a cutting element or insert in accordance with teachings of the

present disclosure may allow improved cooling of the cutting element or insert.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete and thorough understanding of the present embodiments and advantages thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings, in which like reference numbers indicate like features.

FIGURES IA and IB illustrate example tubular tungsten carbide substrates for an IBD cutter.

FIGURES 2A-2C illustrate an example tubular tungsten carbide IBD cutting element coupled to a blade of a cutting tool, according to one embodiment.

FIGURES 3A and 3B illustrate an example beveled tubular tungsten carbide IBD cutting element coupled to a blade of a cutting tool, according to one embodiment.

FIGURES 4A and 4B illustrate an example plow shaped IBD cutting element coupled to the substrate, according to one embodiment. FIGURES 5A and 5B illustrate an example IBD cutting element for use on a Hedge Hog type impregnated bit layout, according to one embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The terms "cutting element" and "cutting elements" may be used in this application to include various types of compacts, inserts, milled teeth and welded compacts satisfactory for use with roller cone drill bits.

The recent development of Intermetallic Bonded Diamond (IBD) allows drill bit cutters and drill bits to be designed outside of the previous constraints.

The present disclosure embodies cutting elements that take advantage of the IBD technology to produce practical, enabled, and useful wear resistant cutters of non-symmetrical, irregular, or relatively complex geometry for drill bits and down hole tools such as coring equipment and reamers, for example.

In some embodiments, a cutting element may include a substrate having a bonding interface region, and an intermetallic bonded diamond (IBD) element bonded to the bonding interface region of the substrate. The bonding interface region may comprise the entire substrate or a portion of the substrate. The substrate may be formed from tungsten carbide, steel, or any other suitable material (s). The IBD element may be bonded to the bonding interface region of the substrate by hot isostatic pressing (HIP) , or in any other suitable manner .

As discussed above, an IBD cutter may be formed having a non-symmetrical, irregular, or relatively complex geometry. In some embodiments, the bonding interface region of the substrate has a non-axi- symmetrical shape. In some embodiments, the bonding interface region may be symmetrical about only one plane, or not symmetrical about any plane. The bonding interface region of the substrate may include a hole extending partially or completely through the substrate. In some embodiments, the bonding interface region of the substrate may have the shape of a tube (see, e.g., FIGURES 1 and 2), a beveled tube (see, e.g., FIGURE 3), a tube with one or more internal support structures, a scoop, a plow (see, e.g., FIGURE 4), a concave shape, a honeycombed shape, or any other suitable

shape. In a particular embodiment, the bonding interface region of the substrate has a plow shape with an included angle of less than or equal to about 100 degrees.

IBD when coupled with tubular, scoop shaped, plow shaped, concave, honeycomb, or other irregular or relatively complex-shaped substrates (e.g., as discussed above) may allow the bit designer unprecedented freedom in cuttings management, cutter cooling, and/or abrasives evacuation leading to enhanced drill bit performance. Bits can be designed that replace traditional PDC cutters with IBD cutters of a more efficient geometry.

IBD cutters may also allow the bit designer to employ mixes or patterns of IBD cutters with traditional PDC cutters or with traditional tungsten carbide inserts to achieve positive effects for specific rock types. Some of these effects may include, e.g., kerfing, impact management and mitigation, cutting force management, secondary cutting, enhanced gage protection, and/or bi-modal deployments for transitional drilling. In addition, IBD cutters may be deployed for hard rock drilling, IADC rock codes 3,7, and 8 by configuring the IBD cutters to replace traditional impregnated segments, impregnated posts, or impregnated discs. IBD cutters may also be used in conjunction with these traditional impregnated diamond cutting elements to achieve synergistic effects, e.g., kerfing, secondary cutting, impact management, and/or transitional drilling benefits .

Some fixed cutter drill bits may be manufactured with a bit body (not expressly shown) having one end operable for attachment to a drill string. The drill string may apply weight to the drill bit, sometimes

referred to as "weight on bit" or WOB. The drill string may also rotate the drill bit (revolutions per minute or RPM) relative to a bit rotational axis extending through the bit body. The drill string may also supply drilling fluid to a cavity formed within the bit body.

A plurality of blades may be disposed on and extend from the bit body. Exterior portions of the blades and associated cutters may form a bit face profile. For some applications the blades may cooperate with each other to form a bit face profile having an inverted, generally cone shaped configuration opposite from the one end of the bit body.

For such applications, one or more tungsten carbide substrates maybe formed with one or more layers of IBD disposed thereon. Each substrate may include a respective post sized to be received within a respective opening formed in the bit body proximate the inverted cone shaped portion of the bit face profile. For some embodiments, an opening may be formed in the bit body proximate the bit rotational axis. For such embodiments, one or more tungsten carbide (WC) blades or plates covered with IBD may be held in place by brazing the posts into respective holes formed proximate the bit rotational axis. Such blades or plates may make the layout and manufacturing of the drill bit center more efficient than current practice even with standard cylindrical PDC cutters.

IBD cutters may offer an attractive, cost effective replacement for dome PDC for use in roller cone bit primary cutting structures, gage row cutting structures, in shirttail protection, and/or in various other structures or applications.

IBD materials may be directly brazed to steel. Thus, cylinders made entirely of IBD can be used as direct replacements in steel body or matrix PDC bit designs without the need for a WC substrate. Such a configuration may dramatically increase the total deployed diamond carat weight for a given bit configuration compared to using conventional PDC. It may also allow for fewer blades on a bit for a given carat weight to increase drill bit penetration rate for a given weight on bit. In addition, IBD may carry diamond up to 700 microns in size. The coarsest grain size diamond typically used in PDC cutters is about 60 microns. Larger size diamonds generally allow for more aggressive angular cutting edges. This attribute may aid in extending typical applications for IBD drill bits to harder rock even when the cutters are deployed in configurations similar to current PDC type drill bit products .

Another advantage of IBD cutters according to the present disclosure is the fact that IBD cutters may not suffer from the deleterious effects usually resulting from the frictional contact of diamond or PDC with ferrous materials. Technical reports made by Southern Illinois University indicate that an IBD sample was run against a cast iron target for 9 hours with minimum wear or damage to the IBD. Thus, the principles of the present disclosure may be used to improve the design and implementation of casing milling, casing window, and drill-out bits. It may also make possible the deployment of a combination mill out and drill ahead bit that does not suffer undue amounts of wear and short service life

due to the typical damage incurred through ferrous contact during the window milling operation.

Preferred embodiments of the invention may be better understood by reference to FIGURES 1A-5E. FIGURES IA and IB illustrate example tubular tungsten carbide substrates for an IBD cutter.

FIGURES 2A-2C illustrate an example tungsten carbide tubular IBD cutting element coupled to a blade of a cutting tool, according to one embodiment. In particular, FIGURE 2A is a side cross-sectional view illustrating a tubular tungsten carbide (WC) substrate coupled to a steel blade. An IBD element is bonded (e.g., by hot isostatic pressing) to an interface region of the substrate. FIGURE 2B illustrates a partial three- dimensional view of the tubular cutting element and steel blade. FIGURE 2C illustrates an end view of an alternative embodiment in which a support structure is positioned within the tubular cutting element, e.g., to provide structural support to the cutting element. One or more such structural supports having any suitable configuration may be included to provide additional structural support to the cutting element.

FIGURES 3A and 3B illustrate an example beveled tubular tungsten carbide IBD cutting element coupled to a blade of a cutting tool, according to one embodiment. In particular, FIGURE 3A is a side cross-sectional view illustrating a beveled tubular tungsten carbide (WC) substrate coupled to a steel blade. An IBD element is bonded (e.g., by hot isostatic pressing) to an interface region of the substrate. FIGURE 3B illustrates a partial three-dimensional view of the beveled tubular cutting element and steel blade. In other embodiments, one or

more structural supports may be included to provide additional structural support to the cutting element, e.g., as discussed above regarding FIGURE 2C.

FIGURES 4A and 4B illustrate an example plow shaped IBD cutting element coupled, according to one embodiment. In particular, FIGURE 4A is a cross-sectional view illustrating a plow shaped substrate having an IBD element bonded to an interface region of the substrate. FIGURE 4B illustrates a three-dimensional view of the plow shaped cutting element.

FIGURES 5A and 5B illustrate an example IBD cutting element for use on a Hedge Hog type impregnated bit layout, according to one embodiment. In particular, FIGURE 5A is a side view illustrating a substrate (e.g., tungsten carbide or steel post) having an IBD element bonded to an interface region of the substrate, and FIGURE 5B is an end view of the cutting element.

Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alternations can be made herein without departing from the spirit and scope of the invention as defined by the following claims .