Patent Application
20240401414
Wellbores for the oil and gas industry are commonly drilled by a process of rotary drilling. In conventional rotary drilling, a drill bit is mounted to the end of a drill string, which may be extended to reach a desired depth by progressively adding tubing segments on site while drilling. In some drilling configurations, a rotary table or top drive included on a drilling rig turns the drill string, including the drill bit arranged within the wellbore, to progressively penetrate the subterranean formation while drilling fluid is pumped through the drill string. In other drilling configurations, the drill bit may be rotated using a downhole mud motor arranged adjacent the drill bit in the downhole environment and powered, for example, using the circulating drilling fluid.
A common type of drill bit used to drill wellbores is known as a “fixed cutter” bit, which includes blades with cutters mounted thereon. As the drill bit rotates, and due to the alignment of the cutters positioned on the blades, the cutters make contact with the subterranean formation and deepen the wellbore by progressively shearing away layers of the subterranean rock.
Due to the hardness of the subterranean rock and the downhole drilling conditions to which the cutters are exposed, the cutters may dull or even evacuate (dislodge from) the body of the drill bit entirely. Oftentimes, the initial cutter installation is influential in extending the life of the cutter within the fixed-cutter blades.
Accordingly, an efficient means of cutter installation and cutter retention is desirable.
Various details of the present disclosure are hereinafter summarized to provide a basic understanding. This summary is not an extensive overview of the disclosure and is neither intended to identify certain elements of the disclosure, nor to delineate the scope thereof. Rather, the primary purpose of this summary is to present some concepts of the disclosure in a simplified form prior to the more detailed description that is presented hereinafter.
According to an embodiment consistent with the present disclosure, a drill bit is disclosed and includes a bit body, one or more blades forming part of the bit body, a plurality of cutter pockets defined in the one or more blades, each cutter pocket providing a floor and an orifice defined in the floor, and a plurality of cutters secured to the one or more blades at the plurality of cutter pockets. Each cutter includes a substrate, a diamond table secured to the substrate at an interface, and a retention feature extending from a bottom surface of the substrate and sized to be received within the orifice of a corresponding one of the plurality of cutter pockets.
According to another embodiment consistent with the present disclosure, a method of securing a cutter to a cutter pocket of a drill bit is disclosed and includes receiving the cutter in the cutter pocket, the cutter including a substrate, a diamond table secured to the substrate at an interface, and a retention feature extending from a bottom surface of the substrate. The method further includes centering the cutter within the cutter pocket by receiving the retention feature in an orifice defined in a floor of the cutter pocket, and attaching the cutter in the cutter pocket while the retention feature is received within the orifice.
According to another embodiment consistent with the present disclosure, a method of manufacturing a cutter for a drill bit is disclosed and includes securing a diamond table to a first end of a substrate, and providing a retention feature on a second end of the substrate opposite the first end. The retention feature comprises a cylindrical body sized to be received within an orifice defined in a floor of a cutter pocket of the drill bit.
According to another embodiment consistent with the present disclosure, a method of retrofitting a drill bit is disclosed and includes forming an orifice defined in a floor of a cutter pocket, and receiving a cutter in the cutter pocket, the cutter including a substrate, a diamond table secured to the substrate at an interface, and a retention feature extending from a bottom surface of the substrate. The method further includes centering the cutter within the cutter pocket by receiving the retention feature in the orifice, and attaching the cutter in the cutter pocket while the retention feature is received within the orifice.
Any combinations of the various embodiments and implementations disclosed herein can be used in a further embodiment, consistent with the disclosure. These and other aspects and features can be appreciated from the following description of certain embodiments presented herein in accordance with the disclosure and the accompanying drawings and claims.
The following figures are included to illustrate certain aspects of the present disclosure, and should not be viewed as exclusive embodiments. The subject matter disclosed is capable of considerable modifications, alterations, combinations, and equivalents in form and function, without departing from the scope of this disclosure.
Embodiments in accordance with the present disclosure generally relate to mounting cutters to fixed-cutter drill bits and, more particularly, to polycrystalline diamond compact (PDC) cutters that include retention features that help retain the cutters within corresponding pockets of the drill bit.
PDC cutters for fixed cutter drill bits (both tungsten and matrix) are typically brazed in place within their corresponding bit pockets. While drilling a wellbore, varying drilling conditions (e.g., flow rates, axial forces, heavy vibrations, erosion, etc.) can lead to PDC cutters evacuating (dislodging from) a manufactured bit pocket. Moreover, since brazing is largely a human process, there is potential for cutters to be lost due to impurities present during the brazing process and/or improper brazing procedures. When PDC cutters are lost during drilling operations, drill bits are often prematurely damaged, which can result in lost time due to bit trips or inefficient drilling, while also potentially causing costly damage to the drill bit and inhibiting the ability to repair the drill bit.
Embodiments of the present disclosure describe methods of mechanically retaining PDC cutters in their corresponding bit pocket, and thereby increasing drill bit durability and performance. More particularly, the retention features described herein help mitigate risk of lost cutters during drilling operations, and may also aid in ensuring the proper placement and centralization of the cutter within the fixed-cutter drill bit during installation. The retention features described herein may also ensure a successful brazing operation, where brazing is used to join cutters to the fixed-cutter drill bit during initial installation. Embodiments described herein limit risk exposure to damaged drill bits beyond repair.
A plurality of cutters 112 are secured to the bit body 102 and, more particularly, to the blades 104. Each cutter 112 may be positioned within a corresponding cutter pocket 114 that is sized and shaped to receive the respective cutter 112. The cutters 112 are held in the blades 104 and corresponding cutter pockets 114 at predetermined angular orientations and radial locations to position the cutters 112 at a desired backrake angle against the formation being penetrated. As the bit body 102 is rotated, the cutters 112 are driven against and through the underlying rock formation by the combined forces of weight-on-bit and torque assumed at the drill bit 100.
During manufacture of the drill bit 100, the cutters 112 are secured (attached) within the pockets 114 by brazing, which is a well-known method of joining materials of differing metallurgy via heat. Because the brazing process is traditionally performed by a human, there is potential for human error and impurities presented in the braze material (e.g., metal solder), which may result in the loss of cutters 112 when the drill bit 100 is placed in use and otherwise exposed to downhole drilling conditions. To ensure a consistent braze, operators will often utilize some method or means of holding the cutter 112 in place during the brazing process. However, despite such an attempt to retain the cutter 112 in place, the cutters 112 may tend to “float” within the pockets 114 while the braze is being applied. In such instances, upon cooling, the cutter 112 may not be secured or seated as originally designed within the pocket 114. Such an anomaly may leave the cutter 112 susceptible to both damage and loss.
Downhole drilling conditions, including flow rates, axial forces, heavy vibration, and erosion, will inevitably lessen the life of the cutters 112. In some cases, drilling conditions and parameters may cause the cutters 112 to be dislodged from their respective pockets 114 during drilling operation. A gap between the bottom surface of the cutter 112 and the pocket 114 may result from poor brazing practices, which can further increase the risk of cutter 112 evacuation and potential downhole loss. A loss of a plurality of the cutters 112 may require the drill bit 100 to be returned to surface for repair or replacement earlier than planned, thus resulting in added time and cost.
According to embodiments of the present disclosure, the cutters 112 secured to the drill bit 100 may include a retention feature that serves to securely hold the cutter 112 in place within both steel and matrix drill bits. The retention features described herein aid in at least two ways. First, the retention features assist in ensuring proper placement and centering of the cutter 112 within the corresponding pocket 114 during brazing operations. The cutters 112 are not prone to “floating” because the retention features eliminate the need for an external retention device during brazing. Retained cutters 112 offer improved quality assurance of the position of the cutter 112 within the drill bit 100, or more particularly, the pocket 114. Second, the retention features disclosed herein help increase the likelihood that the cutter 112 will remain in place even when exposed to extreme downhole drilling conditions. The retention features mitigate risk of premature bit failures due to loss of cutters 112.
Each orifice 202 may be configured to receive a retaining feature of a corresponding cutter, which helps to ensure proper placement, retention, and centralization of the cutter within the pocket 114. The orifice 202 will generally exhibit the same cross-sectional shape as the retaining feature, but could alternatively exhibit a dissimilar cross-sectional shape, without departing from the scope of the disclosure. In the illustrated embodiment, for example, the orifices 202 exhibit a generally circular cross-sectional shape, but it is contemplated herein that one or more of the orifices 202 may exhibit other cross-sectional shapes, such as oval, ovoid, or polygonal (e.g., triangular, rectangular, pentagonal, hexagonal, etc.), gear toothed (e.g., castellated), and thereby configured to receive a correspondingly shaped retaining feature.
The diamond table 304 may incorporate one or more layers of ultra-hard material, including but not limited to polycrystalline diamond (PCD), polycrystalline cubic boron nitride, sintered tungsten carbide, thermally stable polycrystalline (TSP), natural or synthetic diamond, hardened steel, or any combination thereof. Accordingly, the resulting cutter 112 may be characterized and otherwise referred to herein as a “polycrystalline diamond compact” cutter 112 or a PDC cutter 112. The particular composition of the diamond table 304, however, is not limiting to the scope of this disclosure.
The cutter 112 provides a bottom surface 308 opposite the diamond table 304. When the cutter 112 is positioned in a corresponding pocket 114 (
According to embodiments of the present disclosure, the cutter 112 further includes a retention feature 312 extending from the bottom surface 308. As illustrated, the retention feature 312 comprises a generally cylindrical body 314. In some embodiments, the body 314 may be concentrically arranged with a central axis 316 of the cutter 112. In other embodiments, however, the body 314 may be eccentric to the central axis 316, without departing from the scope of the disclosure. The body 314 may be in the form of a pin or axial protrusion (projection) that extends along (or eccentric to) the central axis 316.
The retention feature 312 may extend from the bottom surface 308 and along the central axis 316. In some embodiments, the retention feature 312 may form an integral part or extension of the material of the substrate 302. In such embodiments, the retention feature 312 may be formed from and otherwise milled out of a portion of the substrate 302. In other embodiments, however, the retention feature 312 may comprise a separate component part operatively and fixedly attached to the bottom surface 308, without departing from the scope of the disclosure.
The body 314 is sized and configured to be received within a corresponding orifice 202 (
Having a similar cross-sectional shape for the body 314 and the corresponding orifice 202 may prove advantageous in rehabilitating a drill bit. More specifically, drill bits are often rehabilitated by removing and rotating a cutter 112 within the cutter pocket 114 so that an unused (less-used) edge of the cutter 112 may be exposed. When it is desired to rehabilitate a drill bit, the cutter 112 may be removed from the corresponding pocket 114, rotated a predetermined angular magnitude (e.g., 45°), and re-installed in the pocket 114 for future use. By rotating the cutter 112, a less-used portion of the diamond table 304 may be aligned to engage the underlying rock during operation, thus prolonging the useful life of the cutter 112 and the drill bit.
In embodiments where the body 314 exhibits a circular cross-sectional shape, a diameter of the body 314 may be about 50% or less than a diameter of the substrate 302. In other embodiments where the body 314 exhibits a circular cross-section shape, a diameter of the body 314 may be about 80% or less than a diameter of the substrate 302. Accordingly, the diameter of the body 314, may be some percentage of the diameter of the substrate 302, without exceeding the scope of this disclosure. Moreover, the retention feature 312 defines a bottom face 318 that extends in a plane that is substantially parallel with a plane extending through the bottom surface 308 of the substrate 302. In other embodiments, the bottom face 318 may extend and a plane that is nonparallel to the plane extending through the bottom surface 308.
The cutter 112 may be advanced into the corresponding cutter pocket 114 such that the bottom face of the retention feature 312 rests against or is within close proximity to a distal end 402 of the orifice 202. In at least one embodiment, the bottom face 318 may be within several thousandths of an inch of the distal end 402 of the orifice 202. In other embodiments, the bottom face 318 may be completely flush with the distal end 402 of the orifice 202.
In some embodiments, the retention feature 312 may be received within the corresponding orifice 202 via an interference fit. In other embodiments, however, the retention feature may be loosely received within the corresponding orifice 202.
As discussed above, the most common method of securing (attaching) cutters 112 within corresponding pockets 114 is brazing. The retention feature 312 may prove advantageous in helping to eliminate the need for any external application of force to hold the cutter 112 in place during brazing. Rather, the retention feature 312 is mechanically retained within the orifice 202 such that the cutter 112 is held in place (stationary) during the attachment (brazing) process. Similarly, because the orifice 202 is mechanically defined within the interior of the pocket 114, the retention feature 312 centers the cutter 112 with the pocket 114. Centralization of the cutter 112 may be beneficial in aligning the cutter 112 to the desired backrake angle and creates optimal braze joint thickness.
Therefore, the disclosed systems and methods are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular embodiments disclosed above are illustrative only, as the teachings of the present disclosure may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. It is therefore evident that the particular illustrative embodiments disclosed above may be altered, combined, or modified and all such variations are considered within the scope of the present disclosure. The systems and methods illustratively disclosed herein may suitably be practiced in the absence of any element that is not specifically disclosed herein and/or any optional element disclosed herein. While compositions and methods are described in terms of “comprising,” “containing,” or “including” various components or steps, the compositions and methods can also “consist essentially of” or “consist of” the various components and steps. All numbers and ranges disclosed above may vary by some amount. Whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range is specifically disclosed. In particular, every range of values (of the form, “from about a to about b,” or, equivalently, “from approximately a to b,” or, equivalently, “from approximately a-b”) disclosed herein is to be understood to set forth every number and range encompassed within the broader range of values. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the elements that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.
As used herein, the phrase “at least one of” preceding a series of items, with the terms “and” or “or” to separate any of the items, modifies the list as a whole, rather than each member of the list (i.e., each item). The phrase “at least one of” allows a meaning that includes at least one of any one of the items, and/or at least one of any combination of the items, and/or at least one of each of the items. By way of example, the phrases “at least one of A, B, and C” or “at least one of A, B, or C” each refer to only A, only B, or only C; any combination of A, B, and C; and/or at least one of each of A, B, and C.
The use of directional terms such as above, below, upper, lower, upward, downward, left, right, uphole, downhole and the like are used in relation to the illustrative embodiments as they are depicted in the figures, the upward direction being toward the top of the corresponding figure and the downward direction being toward the bottom of the corresponding figure, the uphole direction being toward the surface of the well and the downhole direction being toward the toe of the well.
| Number | Date | Country | |
|---|---|---|---|
| 63506292 | Jun 2023 | US |
