Roller cone hybrid bit with PDC gauge transition region

Abstract

A drill bit with fixed blades and roller cones that has a bit cutting profile. The bit cutting profile is made up of the fixed cutting profile and the roller cone cutting profile such that fixed cutting elements are positioned outside of the gauge of the drill bit in a portion of the gauge region and where the roller cone cutting elements are positioned outward from the fixed cutting elements in the innermost, central and transition regions of the drill bit.

Description

Docket No. IS24.0982-WO-PCTTITLE ROLLER CONE HYBRID BIT WITH PDC GAUGE TRANSITION REGIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application 63 / 720,583 filed on 14 November 2024. The disclosure of which is incorporated herein by reference in its entirety.BACKGROUND

[0002] The majority of footage drilled in an earth formation uses a plurality of fixed cutting elements to scrape and fracture rock and other material in the downhole environment. The torque experienced by the cutting elements of the drill bit varies with the radial position of the cutting element as well as the depth of cut and strength of the formation. The various positions of the cutting elements can have an impact on the cutting efficiency of the bit and overall process.

[0003] Well bore drill bits can be configured in a variety of different configurations that can include fixed inserts, moving elements, or a combination of fixed and moving elements. The various configurations can be based on the formation in which drilling is to take place. Cutting efficiency is highly important to improve the time it takes to drill the wellbore and produce the oil and gas needed. Accordingly, there is a need to develop improved drill bits and drill bit components to aid in the overall efficiency of the system.SUMMARY

[0004] Summary of the claims - will complete when we have the claims complete

[0005] Many embodiments are directed towards a drill bit a bit body, the bit body having a central rotational axis and at least one fixed blade disposed on the bit body, the at least one fixed blade having a plurality of fixed cutting elements defining a fixed cutting profile, wherein the fixed cutting profile extends radially from the central rotational axis along a central region through a transition region and to a PDC gauge region. Additionally the bit body has at least one roller cone rotationally connected to the bit body, wherein the at least one roller cone comprises a plurality of roller cone cutting elements, wherein the plurality of roller cone cutting elements define a roller cone cutting profile such that the roller cone cutting profile extends radially from the centralDocket No. IS24.0982-WO-PCTrotational axis along a central region into the transition region. The roller cone cutting profile extends beyond the fixed cutting profile in the central region and the transition region, and wherein the roller cone cutting profile ends within the transition region prior to the PDC gauge region.

[0006] In other embodiments, the drill bit further defines a gauge profile, and wherein at least a portion of the fixed cutting elements are disposed in the PDC gauge region such that the fixed cutting profile extends to the gauge profile

[0007] In still other embodiments, the roller cone cutting elements in the transition region are positioned at least 0.25” from a gauge of the drill bit

[0008] In yet more embodiments, at least one of the plurality of fixed cutting elements are positioned a distance from a gauge of the drill bit and positioned substantially parallel with the gauge of the drill bit.

[0009] In still yet other embodiments, the distance is greater than 0.035 inches from the gauge of the drill bit.

[0010] In some embodiments, the distance is greater than the gauge of the drill bit between 0.001 and 0.020 inches.

[0011] In other embodiments, at least some of the plurality of rolling cone cutting elements are carbide.

[0012] In still other embodiments, at least some of the plurality of rolling cone cutting elements are made of a wear resistant material.

[0013] Other embodiments are directed towards a hybrid drill bit a bit body, the bit body having a central rotational axis and a plurality of fixed blades disposed on the bit body, the at least one fixed blade having a plurality of fixed cutting elements defining a fixed cutting profile, wherein the fixed cutting profile extends radially from the central rotational axis along a central region to a transition region and to a PDC gauge region. Additionally, the drill bit has a plurality of roller cones rotationally connected to the bit body, wherein the at least one roller cone comprises a plurality of roller cone cutting elements, wherein the plurality of roller cone cutting elements define a roller cone cutting profile such that the roller cone cutting profile extends radially from the central rotational axis along a central region into the transition region. The roller cone cutting profile extends beyond the fixed cutting profile in the central region and the transition region, and wherein the roller cone cutting profile ends before the PDC gauge regionDocket No. IS24.0982-WO-PCT

[0014] Other embodiments are directed towards drill bit with a bit body, the bit body having a central rotational axis and a plurality of fixed blades disposed on the bit body, the at least one fixed blade having a plurality of fixed cutting elements defining a fixed cutting profile, wherein the fixed cutting profile extends radially from the central rotational axis along a central region to a transition region and to a PDC gauge region. Additionally, the drill bit has a plurality of roller cones rotationally connected to the bit body, wherein the at least one roller cone comprises a plurality of roller cone cutting elements such that the roller cone cutting elements are disposed on the plurality of roller cones having at least two alternating columns and an intersecting row of roller cone cutting element, and wherein the plurality of roller cone cutting elements define a roller cone cutting profile such that the roller cone cutting profile extends radially from the central rotational axis along a central region into the transition region. The roller cone cutting profile extends beyond the fixed cutting profile in the central region and the transition region, and wherein the roller cone cutting profile ends just prior to the PDC gauge region.

[0015] In still yet other embodiments, the alternating rows of cutting elements are diamond cutting elements.

[0016] In some embodiments, the intersecting row of cutting elements are diamond cutting elements.

[0017] In other embodiments, the drill bit has a reverse angled column of cutting elements between the at least two alternating columns.

[0018] Other embodiments are directed to a drill bit with a bit body, the bit body having a central rotational axis and at least one fixed blade disposed on the bit body, the at least one fixed blade having a plurality of fixed cutting elements having a defined fixed cutter profile height. Additionally the bit has at least one roller cone rotationally connected to the bit body, wherein the at least one roller cone comprises a plurality of roller cone cutting elements, each having a roller cone cutting element profile height, wherein each of the plurality of roller cone cutting elements are spaced apart by an angular distance defining a chordal drop. The fixed cutter profile height is different than the roller cone cutting profile height.

[0019] In still yet other embodiments, the chordal drop does not exceed 0.042 inches

[0020] In some embodiments, the angular distance between each of the plurality of roller cone cutting element is no greater than 15°.Docket No. IS24.0982-WO-PCT

[0021] In other embodiments, the roller cone cutting profile height exceeds the fixed cutter profile height by no more than 0.020 inches

[0022] Many embodiments are directed towards a roller cone with a body concentrically formed around a cone axis. The body extends from an outer region to a nose region, wherein the nose region is positioned radially outward from a point along the cone axis such that the nose region has a blunted cross-sectional shape. The blunted cross-sectional shape is configured to contact a formation with a wider surface area. There are also a plurality of inserts disposed on the body of the roller cone. Additionally, there are a plurality of cutting elements disposed on the nose region, wherein at least one of the plurality of cutting elements has at least one cutting edge.

[0023] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.

[0024] Additional features and aspects of embodiments of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of such embodiments. The features and aspects of such embodiments may be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features will become more fully apparent from the following description and appended claims or may be learned by the practice of such embodiments as set forth hereinafter.BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to describe the manner in which the above-recited and other features of the disclosure can be obtained, a more particular description will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. For better understanding, the like elements have been designated by like reference numbers throughout the various accompanying figures. While some of the drawings may be schematic or exaggerated representations of concepts, non-schematic drawings should be considered as being to scale for some embodiments of the present disclosure, but not to scale for other embodiments contemplated herein. Understanding that the drawings depict some example embodiments, the embodiments willDocket No. IS24.0982-WO-PCTbe described and explained with additional specificity and detail through the use of the accompanying drawings in which:

[0026] Fig. 1 illustrates an embodiment of a drilling system and downhole environment in which a drill bit, according to the present disclosure, may be used.

[0027] Figs. 2A and 2B illustrate bottom views of a hybrid drill bit with different positioned cones in accordance with embodiments.

[0028] Fig. 3 illustrates a bottom view of a hybrid drill bit in accordance with embodiments.

[0029] Fig. 4 illustrates a cutter profile of a hybrid drill bit in accordance with embodiments.

[0030] Figs. 5A and 5B illustrate different views of an overlapping fixed and roller cone cutting profile in accordance with embodiments.

[0031] Fig. 6 illustrates a cutter profile in accordance with embodiments.

[0032] Figs. 7A and 7B illustrate side views of a roller cone in accordance with embodiments.

[0033] Figs. 8A and 8B illustrate profile views of cutting elements in accordance with embodiments.DETAILED DESCRIPTION

[0034] Embodiments of the present disclosure generally relate to devices, systems, and methods for drilling in an earth formation. More particularly, some embodiments of the present disclosure relate to hybrid drill bits for degrading and / or removing material from the earth formation. In some embodiments, a drill bit includes a roller cone and a fixed blade in sequence to crack, crush, deform, or otherwise degrade the material of the earth formation before removing the degraded material. In some embodiments, the roller cone of the hybrid drill bit is configured to roll across a surface of the formation material of the earth formation to apply a compression force and / or a shear force to degrade the formation material into a degraded material, and the fixed blade is configured to drag across or through the degraded material to remove at least a portion of the degraded material.

[0035] In some embodiments, a drill bit according to the present disclosure includes a bit body with a rotational axis. In various embodiments, the roller cone(s) is(are) supported by the bit body and rotatable around a cone axis that is oriented substantially radially to the rotational axis of the bit body, such that the roller cone rotates around the cone axis while the bit body rotates aroundDocket No. IS24.0982-WO-PCTthe rotational axis. In some embodiments, the drill bit may further include a fixed blade or multiple fixed blades that remain fixed relative to and / or integrally formed with the bit body. The roller cone and the fixed blade each may include a plurality of cutting elements affixed thereto. In many embodiments, the hybrid drill bit will have a distinct cutter profile. The cutter profile can consist of two separate profiles for each of the roller cone(s) and the fixed blade(s) cutting elements. In various embodiments the cutting profile of the roller cone will extend beyond the cutting profile of the fixed blade cutting elements in a nose and shoulder region of the bit. In other embodiments, the roller cone will have one or more cutting elements positioned within a transition zone or transition region in which the cutting profile transitions or transfers between a shoulder region and the gauge region. Another way to describe or illustrate embodiments with a transition region would be a portion of the roller cone or cutting structure in which there is a transition or change between the more bottom cutting elements, or those that cut the bottom of the hole, and the hole wall cutting elements or those that cut the sidewalls of the wellbore. In many embodiments, the cutting profile of the roller cone(s) will extend beyond the fixed blade cutting profile in the transition region and remain such that the profile up to or less than the gage diameter of the drill bit. In numerous embodiments, the hybrid drill bit will have fixed cutting elements within a gauge region and configured such that their position may gradually transition between a position which creates a cutting profile less than gauge profile to a profile that extends to the full gauge profile.

[0036] Roller cone bits, including hybrid bits, have been in practice for some time. Roller cone bits often include one or more moving or rolling cone elements. The roller cone elements can have a variety of different cutting elements disposed thereon that traditionally have been used for crushing the formation in which the drill bit contacts. The crushing inserts are often pointed, or conical in shape and designed to break up the formation or prepare the formation for a more aggressive cutting from other cutting elements. In some hybrid configurations the drill bit may have fixed blades attached to or formed as part of the bit body. The fixed blades are often configured with multiple cutting elements that are designed to cut away the formation rather than crush it. The fixed blade cutting elements can be configured to follow the path of the roller cone cutting elements and remove material that has been crushed or impacted by the roller cone cutting elements. Accordingly, such fixed blade cutting elements tend to be made from an ultrahard material or wear resistant, thus allowing for hybrid bits to do both crushing and cutting.Docket No. IS24.0982-WO-PCT

[0037] A drill bit, whether hybrid or not, will have a cutting profile. The cutting profile is the profile that can be described as a spline that extends along the path of the cutting elements for a given drill bit and a given part of the drill bit. For example, a fixed cutting blade of a drill bit may extend radially, from a central location near the central axis of a drill bit, to a gage region or outer most region of the drill bit. Each fixed blade can be configured with several different cutting elements. Those cutting elements can be positioned in any desirable configuration along the blade. The cutting elements may extend above the main blade body to a determined position or height. Each of the cutting elements representing a point along a line that may run along the edges of the cutting elements. This line can form a cutting profile for the fixed blade.

[0038] Likewise, roller cone elements on a drill bit can have their own distinct and unique cutting profile. The roller cone cutting profile, like a fixed blade, can represent the cutting elements in different regions or sections of the drill bit. Some roller cones may have cutting elements in the nose region or inner most region, some may be in a central region, some may be in a shoulder region or an outer region. Some elements may be in a gauge region or outer most region while others still may be in a transition region. In some embodiments, the transition region may be between the shoulder region and the gauge region

[0039] Accordingly, many embodiments described herein have improved designs of the roller cones to include improved cutting profiles and improved roller cone profiles that improve the effective cutting capabilities of the roller cone and the drill bit overall. Such designs can help to reduce the wear on the various components of the drill bit and cutters and thus improve the overall functionality of the drill bit during drilling operations. As should be appreciated and as will be described herein, many embodiments will incorporate various hybrid bit designs that improve upon more traditional hybrid roller cone bits using different cutting profdes and / or different cutter designs.

[0040] FIG. 1 illustrates an embodiment of a drilling system and downhole environment in which a drill bit, according to the present disclosure may, be used. FIG. 1 shows one example of a drilling system 100 for drilling an earth formation 101 to form a wellbore 102. The drilling system 100 may include a drill rig 103 used to turn a drilling assembly 104 which extends downward into the wellbore 102. The drilling assembly 104 may include a drill string 105 and a bottomhole assembly (BHA) 106 attached to the downhole end of the drill string 105. Where the drilling system 100 isDocket No. IS24.0982-WO-PCTused for drilling formation, a drill bit 110 can be included at the downhole end of the bottom hole assembly orBHA 106.

[0041] The drill string 105 may include several joints of drill pipe 108 connected end-to-end through tool joints 109. The drill string 105 transmits drilling fluid through a central bore and can transmit rotational power from the drill rig 103 to the BHA 106. In some embodiments, the drill string 105 may further include additional components such as subs, pup joints, etc. The drill pipe 108 provides a hydraulic passage through which drilling fluid 111 is pumped from the surface. The drilling fluid 111 discharges through selected-size nozzles, jets, or other orifices in the bit 110 for the purposes of cooling the bit 110 and cutting structures thereon, for lifting cuttings out of the wellbore 102 as it is being drilled, and for preventing the collapse of the wellbore 102. The drilling fluid 111 carries drill solids including drill fines, drill cuttings, and other swarf from the wellbore 102 to the surface. The drill solids can include components from the earth formation 101, the drilling assembly 104 itself, from other man-made components (e.g., plugs, lost tools / components, etc.), or combinations thereof.

[0042] The BHA 106 may include the bit 110 or other components. An example BHA 106 may include additional or other components (e.g., coupled between to the drill string 105 and / or the bit 110). Examples of additional BHA components can include drill collars, stabilizers, measurementwhile-drilling (MWD) tools, logging-while-drilling (LWD) tools, downhole motors, underreamers, directional steering tools, section mills, hydraulic disconnects, jars, vibration dampening tools, other components, or combinations of the foregoing.

[0043] In general, the drilling system 100 may include other drilling components and accessories, such as special valves (e.g., kelly cocks, blowout preventers, safety valves, centrifuges, shaker tables, and rheometers). Additional components included in the drilling system 100 may be considered a part of the surface system (e.g., drill rig 103, drilling assembly 104, drill string 105, or a part of the BHA 106, depending on their locations and / or use in the drilling system 100).

[0044] The bit 110 in the BHA 106 may include any features or elements suitable for degrading downhole materials. For instance, the bit 110 may be a drill bit suitable for drilling the earth formation 101. While embodiments of a drill bit 110 for drilling the earth formation 101 will be described herein, it should be understood that, in some embodiments, features described herein are applicable to a mill used for removing metal, composite, elastomer, other materials downhole, or combinations thereof. For instance, the bit 110 may be used with a whipstock to mill into casingDocket No. IS24.0982-WO-PCT107 lining the wellbore 102. The bit 110 may also be a junk mill used to mill away tools, plugs, cement, other materials within the wellbore 102, or combinations thereof. Swarf or other cuttings formed by use of a mill may be lifted to surface by the drilling fluid 111 or may be allowed to fall downhole. The conditions of the equipment of the drilling system 100, the formation 101, the wellbore 102, the drilling fluid 111, or other parts of the wellsite can change during operations.

[0045] As should be readily understood by the present disclosure, many embodiments of a BHA may incorporate embodiments of a drill bit that can be a hybrid configuration having one or more roller cones connected to a bit body along with one or more fixed blade elements. Many embodiments of the bit(s) may have different configurations of cutting elements disposed on both the fixed blades as well as the roller cones. As such, many embodiments can have a variety of cutting profiles that factor into the cutting capabilities of the drill bit and the overall longevity of the drill bit.

[0046] As can be appreciated, the fixed blade and roller cone elements of a drill bit can have different features since one element is static, in a sense, and the other is dynamic in relation to the function of the drill bit. The dynamic nature of roller cones on a drill bit allows for different orientations of the roller cone(s) to create different cutting profiles and capabilities of the drill bit. For example, Figs. 2A and 2B illustrate bottom views of a hybrid bit 200 with the roller cones 202 / 203 positioned in different locations with respect to the central rotational axis 204 of the drill bit. For example, Fig. 2A illustrates the hybrid bit where the roller cone rotational axis 206 that is aligned with the central rotational axis 204 of the drill bit. Fig. 2B illustrates a drill bit 200 where the roller cones 203 have a rotational axis 207 that is offset from the central rotational axis by a distance 208. The distance can vary in accordance with many embodiments.

[0047] Unlike fixed blades, roller cones are dynamic elements within the bit. They are designed to roll or rotate about their own rotational axis 206 / 207. As can be seen in Figs. 2A and 2B, the roller cones 202 / 203 can have different engagement areas or engagement zones 210 / 211 with respect to the outermost diameter or gauge 212 of the drill bit. Fig. 2A, for example, illustrates a larger engagement area 210 with the roller cones 202 being aligned with the central rotational axis 204 of the drill bit. In contrast, Fig. 2B illustrates roller cones 203 with the offset 208 and a much smaller engagement area 211. This is due to the offset of the roller cones 203 which only engage the outermost or gauge region 212 of the drill bit during specific rotational positions rather than having a more consistent engagement as shown in Fig. 2B. The offset 208 can ultimately affectDocket No. IS24.0982-WO-PCTthe maximum diameter reach from the central axis of the bit 204 that the cutting elements or cutting inserts (not shown) can reach. This can allow, in various embodiments, the cutting inserts to extend to or cut the gauge or just below the gauge of the drill bit 200. Ultimately this can influence the depth of cut of a roller cone 202 / 203.

[0048] While Figs. 2A and 2B illustrate different positions of roller cones with respect to the drill bit central rotational axis 204, many embodiments of a drill bit may incorporate either design. Additionally, various embodiments of the drill bit may vary the offset such that one cone may have a greater offset than the other. Accordingly, the dynamics and performance of the drill bit may be optimized based on the position of the roller cones and subsequently the cutting elements on the roller cones.

[0049] In accordance with many embodiments, a hybrid drill bit300 similar to that illustrated in Fig. 3, can have a number of different cutting elements 301 on both the fixed blades 302 and the roller cones 304. The cutting elements 301can be positioned in different regions of the drill bit that vary depending on the radial position with respect to the central rotational axis of the drill bit 306. For example, some embodiments of a drill bit may have cutting elements 301 in an inner region 308 that is positioned closer to the central axis of the drill bit 306 than other regions. Cutting elements 301 may also be positioned in a central region 310 that is located radially further than the inner region. Additional cutting elements 301 can be placed in a transition region 312 that can extend from the central region radially outward towards the outermost region 314 of the drill bit. The outermost region 314 can be reflective of the gauge or maximum diameter of the drill bit and correspondingly to the diameter of the well bore. The cutting elements / cutting inserts 301 may be positioned not only in different regions, but also may have different profile heights and density arrangements within the drill bit. The variation of cutting elements can serve to create a desired cutting profile for both the fixed blades 302 and the roller cones 304 and thus create a drill bit optimized for cutting specific formations.

[0050] Fig. 4 illustrates a profile view of various cutting elements 402 / 404 in accordance with various embodiments of a drill bit cutting profile. In many embodiments, the roller cone cutting elements 404 can form a specific roller cone cutting profile 406 represented by the dashed line running adjacent to the tips of the rolling cutting elements 404. Likewise, the fixed cutting elements 402 can form a fixed cutting profile 408, represented by the dashed line running adjacent to the fixed cutting elements 402. As described with respect to Fig. 3, many embodiments of drillDocket No. IS24.0982-WO-PCTbits can be separated or divided into various sections or regions such as the inner region 410, central region 412, transition region 414, and the gauge region 416. These regions are classified by their respective radial location extending outward from the central rotational axis 418 of the drill bit.

[0051] As can be seen, many embodiments of a drill bit cutting profile can have the roller cone cutting elements 404 and thus the roller cone cutting profile 406 extend beyond the fixed cutting profile 408 in the inner region 410, the central region 412, and the transition region 414. In various embodiments, the fixed cutting elements 402 and thus the fixed cutting profile 408 can extend outward to the full gauge of the drill bit 420 in the gauge region. As illustrated, some embodiments of the drill bit cutting profile may have roller cone cutting elements 404 in the transition region that may extend to the gauge of the drill bit 420 within the transition region. Some embodiments may have the roller cone cutting elements 404 in the transition region extend to a position just beneath or just shy of the gauge of the drill bit 420.

[0052] As should be readily appreciated, the position of the roller cone cutting elements 404 within the transition region 414 may only extend to the gauge of the drill bit 420 at certain times or rotations of the roller cone based on the position of the roller cone. For example, as illustrated in Fig. 2B, the roller cone(s) may be offset from the central rotational axis of the drill bit such that the roller cone cutting elements 404 in the transition region are only positioned to contact the formation in the gauge of the drill bit 420 when the cutting elements 404 are rotated be within the engagement zone 211. This is due to the dynamic nature of the roller cone. Accordingly, while Fig. 4 illustrates an embodiment of a drill bit cutting profile that may be reflective of the downward most position of the roller cone cutting element 404. In other words, the roller cone cutting profile 406 is illustrated by the static spline or a continuous curve connecting points on the roller cone cutting inserts 404 when they are oriented in their furthest downward position as measured along the central rotational axis. This illustrates the furthest downward point of each of the roller cone cutting inserts 404 In accordance with many embodiments, the roller cone cutting profile may be optimized with various roller cone cutting elements and specific cutting element configurations to allow for the most effective cutting of the formation from the roller cone.

[0053] Figs. 5A and 5B further illustrate embodiments of a drill bit cutting profile 500 viewed from a profile of a roller cone. Fig. 5A illustrates the various overlapping positions of both the roller cone cutting elements 502 and the fixed cutting elements 504 as they relate to the centralDocket No. IS24.0982-WO-PCTrotational axis of the drill bit 506 and the gauge of the drill bit 508. As illustrated, various embodiments of a roller cone can have roller cone cutting elements 502 within an inner region 510 such that the roller cone cutting elements 502 are closest to the central rotational axis 506 of the drill bit. As the cutting profde moves radially outward from the central rotational axis 506 fixed cutting elements 504 may begin to establish a fixed cutting profile in similar positions as the roller cone cutting elements. In many embodiments, the roller cone cutting elements 502 and thus the roller cone cutting profile may extend axially outward from the fixed cutting elements in a portion of the inner region. Similarly, as the cutting profile 500 extends into a central region 512 the roller cone cutting elements 502 may extend axially outward from the fixed cutting elements 504. The axial difference between the fixed cutting elements 504 and the roller cone cutting elements 502 may vary depending on the radial position or may remain constant.

[0054] In many embodiments of a cutting profile 500 may have transition region 514 in which the roller cone cutting elements 502 extend radially outwards to engage a corner of the bottom of the wellbore. In other words, in some rotational movements of the roller cone, the roller cone cutting elements 502 may be positioned to extend to the comer and / or just below the gauge of the drill bit prior to the gauge region 518 of the drill bit. Accordingly, some embodiments of the roller cone cutting profile will end at the gauge region 518 of the drill bit such that the profile does not extend into the gauge region. In other words, many embodiments may have roller cone cutting elements 502 that have a profile that does not extend to the gauge of the drill bit. In many embodiments, the roller cone cutting elements 502 within the transition region 514 may end or effectively stop such that the roller cone cutting profile ends 0.25 inches of the gauge 508. In other words, various embodiments of the roller cone cutting profile may end within the transition region 514 prior to the PDC gauge 518 and may do so such that the roller cone cutting elements are positioned 0.25 inches from the gauge 508. In some embodiments, the roller cone cutting elements 502 within the transition region 514 may be positioned less than 0.25 inches such that they may be positioned between 0.035 inches and 0.25 inches from the gauge 508. In various embodiments, the roller cone cutting elements 502 within the transition region 514 may be positioned less than 0.035 inches up to even the full gauge of the drill bit.

[0055] In various embodiments, the fixed cutting elements 504 may be positioned in a gauge region 518 of the drill bit such that they are configured to engage the formation at the gauge of the drill bit 508. Accordingly, many embodiments may have at least one fixed cutting elementDocket No. IS24.0982-WO-PCTpositioned at a distance from the gauge of the drill bit. Additionally, some embodiments may have one or more fixed cutting elements 504 positioned substantially parallel with the gauge of the drill bit. In other words, some embodiments may have a cutting profile such that some of the fixed cutting elements 504 extend to or beyond the position of the roller cone cutting elements in the transition region 514. Effectively, this would end the roller cone cutting profile within the transition region 514 or prior to the PDC gauge region 518 ensuring that only fixed cutting elements 504 are positioned within the PDC gauge region 518 of the drill bit.

[0056] Referring now to Fig. 5B, a portion of a drill bit cutting profile 500 is illustrated. The figure illustrates a cutting profile 500 within just the transition region 514 and the PDC gauge region 518, with the figure being rotated 90° from the position illustrated in Fig. 5A. As can be seen, the fixed cutting elements 504 in the PDC gauge region 518 may be positioned such that the profile gradually changes from a position just below the gauge of the drill bit 508 or under the hole wall to a position that extends to the gauge of the drill bit 508. Furthermore, as can be seen in Fig.5B, the roller cone cutting elements 502 and thus the roller cone cutting profile does not extend into the PDC gauge region 518, but rather ends within the transition region 514 of the drill bit.

[0057] Referring now to Fig. 6, a cutting profile 600 of a drill bit is illustrated. In numerous embodiments, the drill bit cutting profile 600 can consist of a combination of two distinct cutting profiles for the various types of cutting elements. For example, numerous embodiments may have a roller cone cutting profile 602 and a fixed cutting profile 604 within the same cutting profile of the drill bit. In some portions of the cutting profile, the roller cone cutting profile 602 may extend further out than that of the fixed cutting profile 604. In many embodiments, the roller cone cutting profile will extend beyond the fixed cutting profile 604 up to the PDC gauge region 608 of the drill bit such that the roller cone cutting profile ends prior to the PDC gauge region 608 of the drill bit. In various embodiments, the fixed cutting profile 604 can extend to the full gauge of the drill bit 606 within the PDC gauge region 608 In some embodiments, the distance between the rolling cone cutting profile 602 and the fixed cutting profile 604 can vary in many embodiments and may be optimized to fit the desired formation. Additionally, such profiles can be optimized based on the size and overall function of the drill bit. Furthermore, it should be understood that the configuration of cutting elements on either the fixed cutting profile and / or the rolling cone cutting profile can be optimized for improved performance.Docket No. IS24.0982-WO-PCT

[0058] Fig. 7A further illustrates an embodiment of a roller cone cutting element configuration. In such embodiments, the roller cone 700 can be configured with numerous rows of cutting elements 702 / 704. The cutting elements 702 / 704 can be of different make up or different hardness and may be made from a wear resistant material. For example, some cutting elements may be a carbide material 702 while others are diamond or ultrahard material 704. In some embodiments, all of the cutting elements 702 / 704 may be of the same material such that they all may be carbide, diamond, or ultrahard material or some combination. Additionally, in many embodiments, the configuration and density of the cutting elements 702 / 704 can vary on the roller cone 700 such that the roller cone is optimized for continued performance. In some embodiments, the diamond or ultrahard cutting elements 704 may consist of two or more alternating columns of cutting elements 705 / 706 and an intersecting row 707 of cutting elements. The intersecting row 707 of cutting elements may be positioned such that it intersects the center of the alternating rows 705 / 706 forming an angled “H” type configuration. Additionally, the angular placement of the rows and columns on the roller cone 700 can result in a reverse angled column 708 connecting the two alternating columns 705 / 706 from the top of one to the bottom or near bottom of the other. Such angular pattern can result in roller cones 700 with optimal rotational performance such that they allow for the roller cone to continue rotating while downhole. The continued rotation downhole can help to allow a drill bit, configured with such roller cone(s) to maintain efficient cutting and prevent the stall of the roller cone 700. Effectively the roller cone cutting elements 702 / 704 may be positioned within a drive zone of the roller cone 700 to allow for various cutting elements to engage the formation and continually drive the roller cone.

[0059] Fig. 7B illustrates a bottom view and an expanded view of a roller cone 700 as shown in Fig. 7A. In many embodiments of the roller cone 700 the cutting elements 702 / 704 within the drive zone 710 may be arranged or place ad different spacings to configure the effective drive 710 zone of the roller cone 700. For example, in some embodiments, some of the cutting elements 702 / 704 may be spaced apart such that a rotational movement of the roller cone will allow for one or more to engage the formation. In various embodiments, the drive zone 710 may be configured such that the cutting elements 704 are configured to engage the formation every 9° of cone rotation. Other embodiments may be configured such the engagement occurs every 7° of cone rotation or 5° of cone rotation. Some embodiments may be configured with a drive zone 710 having cuttingDocket No. IS24.0982-WO-PCTelements 702 / 704 engage every 9.5° or more or less depending on the formation and desired outcome of the wellbore.

[0060] The angular spacing of the cutting elements on the roller cone, in many embodiments, can affect the rotational position of the cutting elements with respect to the formation and can therefore have an effect on the ability of the roller cone to maintain rotation during drilling operations. As such, many embodiments of the roller cone may position the cutting elements at specific rotational angles or angular spacing such that maximum effective contact of the cutting elements is achieved during drilling operations.

[0061] In various embodiments of a hybrid drill bit that has fixed cutters and roller cone cutters only a portion of the Weight on Bit (WOB) is distributed to the roller cone cutting elements to allow them to act as fulcrum points for the roller cone with respect to the formation, thus allowing continuous rotational movement of the roller cone. Additionally, if the distance between the roller cone cutting elements and the fixed cutting elements (proud distance) is not large enough the lack of WOB distribution can further limit the ability for the roller cone cutting elements to imbed themselves into the formation enough to act as the rotational fulcrum points to force the roller cone to rotation. Accordingly, the angular spacing between the rows of roller cone cutting elements can be adjusted and / or varied in numerous embodiments to allow for the proper contact between the roller cone cutting elements and the formation.

[0062] For example, Figs. 8A and 8B illustrate close-up views of angular spacing between cutting elements 802 as well as a spatial relationship between the roller cone cutting elements and the fixed cutting elements 804. The angular spacing between the roller cone cutting elements 802 represented by the arc 806 between the tips of the roller cone cutting elements 806 creates a chordal distance or chordal drop 808 which is the distance between the arc 806 and a linear distance 810 between the two rows of roller cone cutting elements 802. The larger the angular distance the larger the chordal drop. The chordal drop is directly related to the ability of the roller cone cutting elements to act as fulcrum points and allow for continuous rotation of the roller cone. In other words, the greater the spacing the less likely one row of roller cone cutting elements 802 can act as a fulcrum point for the next cutting element 802 and thus can result in some of the cutting elements 802 being within a dwell zone. In accordance with many embodiments, the roller cone cutting elements 802 may be spatially optimized such that the chordal drop is reduces. In some embodiments the chordal drop may be no more than 0.042 inches. In some embodiments theDocket No. IS24.0982-WO-PCTchordal drop may be greater than 0.042 inches. In various embodiments the chordal drop may be between 0.042 inches and 0.020 inches. Some embodiments may have a chordal drop of less than 0.020 inches.

[0063] The chordal drop 808 can be affected by other drill bit configurations such as the cutting profile differences between the roller cone cutting elements 802 and fixed cutting elements 804. In other words, the roller cone cutting elements 802 and the fixed cutting elements 804 may each have a profile height 811 and 813 respectively. The difference between the profile heights 811 / 813 can be referred to as the proud distance 814 or the distance in which the roller cone cutting elements extend beyond the fixed cutting elements 804. The proud distance 814 can vary in accordance with many embodiments and can have a direct effect on the maximum allowable chordal drop 808 in order to maintain the continuous rotation of the roller cone. For example, the as the proud distance 814 increases the angular distance 806 between the roller cone cutting elements 802 could also increase and allow the chordal distance 808 to increase without negatively affecting the cone rotation. Accordingly, many embodiments may optimize the profiles of the roller cone cutting elements and fixed cutting elements to reduce the number or roller cone cutting elements required to allow for continuous cone rotation. In various embodiments the proud distance 812 may be 0.020 inches. In some embodiments the proud distance may be greater than 0.020 inches while other embodiments may have a proud distance less than 0.020 inches.

[0064] It should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. For example, any element described in relation to an embodiment herein may be combinable with any element of any other embodiment described herein, to the extent such features are not described as being mutually exclusive. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about”, “substantially”, or “approximately” the stated value, as would be appreciated by one of ordinary skill in the art encompassed by embodiments of the present disclosure. A stated value should therefore be interpreted broadly enough to encompass values that are at least close enough to the stated value to perform a desired function or achieve a desired result. The stated values include at least the variation to be expected in a suitable manufacturing or production process, and may include values that are within 5%, within 1%, within 0.1%, or within 0.01% of a stated value.Docket No. IS24.0982-WO-PCT

[0065] The terms “approximately,” “about,” and “substantially” as used herein represent an amount close to the stated amount that is within standard manufacturing or process tolerances, or which still performs a desired function or achieves a desired result. For example, the terms “approximately,” “about,” and “substantially” may refer to an amount that is within less than 5% of, within less than 1% of, within less than 0.1% of, and within less than 0.01% of a stated amount. Further, it should be understood that any directions or reference frames in the preceding description are merely relative directions or movements. For example, any references to “up” and “down” or “above” or “below” are merely descriptive of the relative position or movement of the related elements.

[0066] A person having ordinary skill in the art should realize in view of the present disclosure that equivalent constructions do not depart from the spirit and scope of the present disclosure, and that various changes, substitutions, and alterations may be made to embodiments disclosed herein without departing from the spirit and scope of the present disclosure. Equivalent constructions, including functional “means-plus-function” clauses are intended to cover the structures described herein as performing the recited function, including both structural equivalents that operate in the same manner, and equivalent structures that provide the same function. It is the express intention of the applicant not to invoke means-plus-function or other functional claiming for any claim except for those in which the words ‘means for’ appear together with an associated function. Each addition, deletion, and modification to the embodiments that falls within the meaning and scope of the claims is to be embraced by the claims. The described embodiments are therefore to be considered as illustrative and not restrictive, and the scope of the disclosure is indicated by the appended claims rather than by the foregoing description.

Claims

Docket No. IS24.0982-WO-PCTCLAIMSWhat is claimed is:

1. A drill bit comprisingA bit body, the bit body having a central rotational axis.At least one fixed blade disposed on the bit body, the at least one fixed blade having a plurality of fixed cutting elements defining a fixed cutting profile, wherein the fixed cutting profile extends radially from the central rotational axis along a central region through a transition region and to a PDC gauge region,At least one roller cone rotationally connected to the bit body, wherein the at least one roller cone comprises a plurality of roller cone cutting elements, wherein the plurality of roller cone cutting elements define a roller cone cutting profile such that the roller cone cutting profile extends radially from the central rotational axis along a central region into the transition region; andWherein the roller cone cutting profile extends beyond the fixed cutting profile in the central region and the transition region, and wherein the roller cone cutting profile ends within the transition region prior to the PDC gauge region.

2. The drill bit of claim 1, wherein the drill bit further defines a gauge profile, and wherein at least a portion of the fixed cutting elements are disposed in the PDC gauge region such that the fixed cutting profile extends to the gauge profile.

3. The drill bit of claim 1, wherein the roller cone cutting elements in the transition region are positioned at least 0.25” from a gauge of the drill bit.

4. The drill bit of claim 1, wherein at least one of the plurality of fixed cutting elements are positioned a distance from a gauge of the drill bit and positioned substantially parallel with the gauge of the drill bit.

5. The drill bit of claim 4, wherein distance is greater than 0.035 inches from the gauge of the drill bit.Docket No. IS24.0982-WO-PCT6. The drill bit of claim 4, wherein the distance is greater than the gauge of the drill bit between 0.001 and 0.020 inches.

7. The drill bit of claim 1, wherein at least some of the plurality of rolling cone cutting elements are carbide.

8. The drill bit of claim 1, wherein at least some of the plurality of rolling cone cutting elements are made of a wear resistant material.

9. A hybrid drill bit comprising:A bit body, the bit body having a central rotational axis.A plurality of fixed blades disposed on the bit body, the at least one fixed blade having a plurality of fixed cutting elements defining a fixed cutting profile, wherein the fixed cutting profile extends radially from the central rotational axis along a central region to a transition region and to a PDC gauge region,A plurality of roller cones rotationally connected to the bit body, wherein the at least one roller cone comprises a plurality of roller cone cutting elements, wherein the plurality of roller cone cutting elements define a roller cone cutting profile such that the roller cone cutting profile extends radially from the central rotational axis along a central region into the transition region; andWherein the roller cone cutting profile extends beyond the fixed cutting profile in the central region and the transition region, and wherein the roller cone cutting profile ends before the PDC gauge region.

10. The drill bit of claim 9, wherein the drill bit further defines a gauge profile, and wherein at least a portion of the fixed cutting elements are disposed in the gauge region such that the fixed cutting profile extends to the gauge profile.

11. The drill bit of claim 9, wherein the roller cone cutting elements in the transition region are positioned at within 0.25” from a gauge of the drill bit.Docket No. IS24.0982-WO-PCT12. The drill bit of claim 9, wherein at least one of the plurality of fixed cutting elements are positioned a distance from a gauge of the drill bit and positioned substantially parallel with the gauge of the drill bit.

13. The drill bit of claim 12, wherein the distance is greater than 0.035 inches.

14. The drill bit of claim 9, wherein at least some of the plurality of rolling cone cutting elements are carbide.

15. The drill bit of claim 9, wherein at least some of the plurality of rolling cone cutting elements are diamond.

16. A drill bit comprising:A bit body, the bit body having a central rotational axis.A plurality of fixed blades disposed on the bit body, the at least one fixed blade having a plurality of fixed cutting elements defining a fixed cutting profile, wherein the fixed cutting profile extends radially from the central rotational axis along a central region to a transition region and to a PDC gauge region,A plurality of roller cones rotationally connected to the bit body, wherein the at least one roller cone comprises a plurality of roller cone cutting elements such that the roller cone cutting elements are disposed on the plurality of roller cones having at least two alternating columns and an intersecting row of roller cone cutting element, and wherein the plurality of roller cone cutting elements define a roller cone cutting profile such that the roller cone cutting profile extends radially from the central rotational axis along a central region into the transition region; and Wherein the roller cone cutting profile extends beyond the fixed cutting profile in the central region and the transition region, and wherein the roller cone cutting profile ends just prior to the PDC gauge region.

17. The drill bit of claim 16, wherein the alternating rows of cutting elements are diamond cutting elements.Docket No. IS24.0982-WO-PCT18. The drill bit of claim 16, wherein the intersecting row of cutting elements are diamond cutting elements.

19. The drill bit of claim 16, further comprising a reverse angled column of cutting elements between the at least two alternating columns.

20. A drill bit comprisingA bit body, the bit body having a central rotational axis.At least one fixed blade disposed on the bit body, the at least one fixed blade having a plurality of fixed cutting elements having a defined fixed cutter profile height,At least one roller cone rotationally connected to the bit body, wherein the at least one roller cone comprises a plurality of roller cone cutting elements, each having a roller cone cutting element profile height, wherein each of the plurality of roller cone cutting elements are spaced apart by an angular distance defining a chordal drop; andWherein the fixed cutter profile height is different than the roller cone cutting profile height.

21. The drill bit of claim 20, wherein the chordal drop does not exceed 0.042 inches.

22. The drill bit of claim 20, wherein the angular distance between each of the plurality of roller cone cutting element is no greater than 15°.

23. The drill bit of claim 20, wherein the roller cone cutting profile height exceeds the fixed cutter profile height by no more than 0.020 inches.

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