Patent Grant
10125553
The present disclosure relates generally to apparatuses and methods for taking core samples of subterranean formations. More specifically, the present disclosure relates to a core bit having features to control flow of drilling fluid into a narrow annulus between the core bit inside diameter and the outside diameter of an associated core shoe of a coring apparatus for reduction of drilling fluid contact with, and potential invasion and contamination of, a core being cut.
Formation coring is a well-known process in the oil and gas industry. In conventional coring operations, a core barrel assembly is used to cut a cylindrical core from the subterranean formation and to transport the core to the surface for analysis. Analysis of the core can reveal invaluable data concerning subsurface geological formations—including parameters such as permeability, porosity, and fluid saturation—that are useful in the exploration for and production of petroleum, natural gas, and minerals. Such data may also be useful for construction site evaluation and in quarrying operations.
A conventional core barrel assembly typically includes an outer barrel having, at a bottom end, a core bit adapted to cut the cylindrical core and to receive the core in a central opening, or throat. The opposing end of the outer barrel is attached to the end of a drill string, which conventionally comprises a plurality of tubular sections that extends to the surface. Located within, and releasably attached to, the outer barrel is an inner barrel assembly having an inner tube configured for retaining the core. The inner barrel assembly further includes a core shoe disposed at one end of the inner tube adjacent the throat of the core bit. The core shoe is configured to receive the core as it enters the throat and to guide the core into the inner tube. Both the inner tube and core shoe are suspended within the outer barrel with structure permitting the core bit and outer barrel to rotate freely with respect to the inner tube and core shoe, which may remain substantially rotationally stationary. Thus, as the core is cut—by application of weight to the core bit through the outer barrel and drill string in conjunction with rotation of these components—the core will traverse the throat of the core bit to eventually reach the core shoe, which accepts the core and guides it into the inner tube assembly where the core is retained until transported to the surface for examination.
Conventional core bits are generally comprised of a bit body having an annular face surface on a bottom end. The opposing end of the core bit is configured, e.g., by threads, for connection to the outer barrel. Located at the center of the face surface is the throat, which may extend into a substantially hollow cylindrical cavity formed in the bit body. Different types of core bits are known in the industry, such as, by way of non-limiting example, diamond bits, including polycrystalline diamond compact (PDC) bits as well as impregnated bits. In PDC bits, for example, the face surface typically includes a plurality of cutters arranged in a selected pattern. The pattern of cutters includes at least one outside gage cutter disposed near the periphery of the face surface that determines the diameter of the bore hole drilled in the formation during a coring operation. The pattern of cutters also includes at least one inside gage cutter disposed near the throat that determines the outside diameter of the core being cut. It is to be understood, however, that the scope of the present disclosure is not limited to PDC bits, but encompasses other core bit types as well.
During coring operations, a drilling fluid is usually circulated through the core barrel assembly to lubricate and cool the cutting structure of the bit face, such as the plurality of cutters disposed on the face surface of the core bit, and to remove formation cuttings from the bit face surface to be transported upwardly to the surface through the annulus defined between the drill string and the wall of the wellbore. A typical drilling fluid, also termed drilling “mud,” may be a hydrocarbon, a water-based (saltwater or freshwater) or synthetic-based fluid in which fine-grained mineral matter may be suspended, or any other fluid suitable to convey the downhole formation cuttings to the surface. Some core bits include one or more ports or nozzles positioned to deliver drilling fluid to the face surface. Generally, a port includes a port outlet, or “face discharge outlet,” which may optionally comprise a nozzle, at the face surface in fluid communication with a face discharge channel. The face discharge channel extends through the bit body and terminates at a face discharge channel inlet. Each face discharge channel inlet is in fluid communication with an upper annular region formed between the bit body and the inner tube and core shoe. Drilling fluid received from the drill string under pressure is circulated into the upper annular region to the face discharge channel inlet of each face discharge channel to draw drilling fluid from the upper annular region. Drilling fluid then flows through each face discharge channel and discharges at its associated face discharge port to lubricate and cool the plurality of cutters on the face surface and to remove formation cuttings as noted above.
In conventional core barrel assemblies, a narrow annulus exists in the region between the inside diameter of the bit body and the outside diameter of the core shoe. The narrow annulus is essentially an extension of the upper annular region and, accordingly, the narrow annulus is in fluid communication with the upper annular region. Thus, in addition to flowing into the face discharge channel inlets, the pressurized drilling fluid circulating into the upper annular region also flows into the narrow annulus between the bit body and core shoe, also referred to as a “throat discharge channel.” The location at which drilling fluid bypasses the face discharge channel inlets and continues into the throat discharge channel may be referred to as the “flow split.” The throat discharge channel terminates at the entrance to the core shoe proximate the face of the core bit and any drilling fluid flowing within its boundaries is exhausted proximate the throat of the core bit. As a result, drilling fluid flowing from the throat discharge channel will contact the exterior surface of the core being cut as the core traverses the throat and enters the core shoe.
Conventional core barrel assemblies are prone to damage core samples in various ways during operation. For example, core barrel assemblies may be prone to damage core samples by exposing the core to the flow of drilling fluid, particularly if the flow velocity is relatively high and the area of exposure is large. For example, a throat discharge channel through which drilling fluid is discharged with high velocity in the region where the core is exposed to the drilling fluid can create significant problems during coring operations, especially when coring in relatively soft to medium hard formations, or in unconsolidated formations. Drilling fluids discharged from the throat discharge channel enter an unprotected interval where no structure stands between such drilling fluids and the outer surface of the core as the core traverses the throat and enters the core shoe. Such drilling fluid can also invade and contaminate the core itself. For soft or unconsolidated formations, these drilling fluids invading the core may wash away, or otherwise severely disturb, the material of the core. The core may be so badly damaged by the drilling fluid invasion that standard tests for permeability, porosity, and other characteristics produce unreliable results, or cannot be performed at all. The severity of the negative impact of the drilling fluid on the core increases with the velocity of the drilling fluid in the unprotected interval. Fluid invasion of unconsolidated or fragmented cores is a matter of great concern in the petroleum industry as many hydrocarbon-producing formations, such as sand and limestone, are of the unconsolidated type. For harder formations, drilling fluid coming into contact with the core may still penetrate the core, contaminating the core and making it difficult to obtain reliable test data. Thus, limiting fluid invasion of the core can greatly improve core quality and recoverability while yielding a more reliable characterization of the drilled formation.
The problems associated with fluid invasion of core samples described above may be a result, at least in part, of the material comprising the bit body of a core barrel assembly. Conventional core bits often comprise hard particulate materials (e.g., tungsten carbide) dispersed in a metal matrix (commonly referred to as “metal matrix bits”). Metal matrix bits have a highly robust design and construction necessitated by the severe mechanical and chemical environments in which the core bit must operate. However, the dimensional tolerances of metal matrix core bits (including inner surface diameter, gap width of the throat discharge channel, TFA of the face discharge channels and depth of the junk slots) are limited by the strength of the metal matrix material. In such metal matrix core bits, portions of the bit body must exceed a minimal thickness necessary to maintain structural integrity and inhibit the formation of cracks or microfractures therein.
In some embodiments, a coring bit for use on a coring tool for extracting a sample of subterranean formation from a wellbore includes a bit body having a cavity, wherein a throat portion of the cavity extends into the bit body from a face of the bit body. The coring tool also includes a sleeve disposed within the cavity of the bit body. The sleeve is configured to separate at least one face discharge channel and a throat discharge channel. The at least one face discharge channel is located radially outward of the sleeve and the throat discharge channel is located radially inward of the sleeve.
In other embodiments, a method of repairing a coring tool for extracting a sample of subterranean formation from a wellbore includes removing a sleeve from a cavity of a bit body of the coring tool. The sleeve is configured to separate at least one face discharge channel and a throat discharge channel during operation of the coring tool. The at least one face discharge channel is located radially outward of the sleeve and the throat discharge channel is located radially inward of the sleeve.
While the disclosure concludes with claims particularly pointing out and distinctly claiming specific embodiments, various features and advantages of embodiments of the disclosure may be more readily ascertained from the following description when read in conjunction with the accompanying drawings, in which:
The illustrations presented herein are not meant to be actual views of any particular core bit, shoe, or sleeve of a coring tool, or component thereof, but are merely idealized representations employed to describe illustrative embodiments. Thus, the drawings are not necessarily to scale.
The cited references cited herein, regardless of how characterized, are not admitted as prior art relative to the disclosure of the subject matter claimed herein.
As used herein, directional terms, such as “above,” “below,” “up,” “down,” “upward,” “downward,” “top,” “bottom,” “top-most,” “bottom-most,” “proximal” and “distal” are to be interpreted from a reference point of the object so described as such object is located in a vertical wellbore, regardless of the actual orientation of the object so described. For example, the terms “above,” “up,” “upward,” “top,” “top-most” and “proximal” are synonymous with the term “uphole,” as such term is understood in the art of subterranean wellbore drilling. Similarly, the terms “below,” “down,” “downward,” “bottom,” “bottom-most” and “distal” are synonymous with the term “downhole,” as such term is understood in the art of subterranean wellbore drilling.
As used herein, the term “longitudinal” refers to a direction parallel to a longitudinal axis of the core barrel assembly. For example, a “longitudinal” cross-section shall mean a “cross-section viewed in a plane extending along the longitudinal axis of the core barrel assembly.”
As used herein, the terms “lateral,” “laterally,” “transverse” or “transversely” shall mean “transverse to a longitudinal axis of the core barrel assembly.” For example, a “lateral” or “transverse” cross-section shall mean a cross-section viewed in a plane transverse to the longitudinal axis of the core barrel assembly.
Disclosed herein are embodiments of a core barrel assembly with increased effectiveness at reducing the exposure of the core sample to drilling fluid during a coring operation. Decreasing the amount and/or velocity of drilling fluid contacting the core sample may be accomplished by decreasing hydraulic losses, such as fluid flow resistance (also termed “head loss” or “resistance head”) within the face discharge channels and increasing hydraulic losses within the throat discharge channel. Hydraulic losses of the various channels are at least partly a function of the Total Flow Area (TFA) along those channels. Thus, as set forth more fully in the embodiments disclosed below, the hydraulic losses of the face discharge channels may be reduced by increasing the TFA of the face discharge channels, while the hydraulic losses of the throat discharge channel may be increased by reducing the TFA or otherwise increasing the fluid flow resistance of the throat discharge channel. Reducing the hydraulic losses of the face discharge channels or increasing the hydraulic losses of the throat discharge channel may both result in an increase in drilling fluid being diverted from the throat discharge channel and instead flowing through the face discharge channels and away from the core. Such management of the hydraulic losses of the face discharge channels and the throat discharge channel may also reduce the velocity of drilling fluid exiting the throat discharge channel relative to prior art core bits. The maximum TFA of the face discharge channels is limited by the radial space of the bit body and the need to maintain minimum wall thicknesses within the bit body to prevent cracks or microfractures from forming therein. Additionally, the minimum TFA of the throat discharge channel is limited because a sufficient radial gap between an inner surface of the core bit and an outer surface of the core shoe is necessary to allow the core bit to rotate with respect to the core shoe without catching or binding therewith. Embodiments of a core barrel assembly that optimize fluid management therein by increasing the TFA of the face discharge channels and/or decreasing the TFA of the throat discharge channel and/or increasing flow restriction within the throat discharge channel are set forth below. The embodiments disclosed herein also improve the manufacturability and reparability of core bits.
The bit body 10 may comprise steel or a steel alloy, including a maraging steel alloy (i.e., an alloy comprising iron alloyed with nickel and secondary alloying elements such as aluminum, titanium and niobium), and may be formed at least in part as further set forth in U.S. Patent Publication No. 2013/0146366 A1, published Jun. 6, 2013, to Cheng et al. (hereinafter “Cheng”), the disclosure of which is incorporated herein in its entirety by this reference. In other embodiments, the bit body 10 may be an enhanced metal matrix bit body, such as, for example, a pressed and sintered metal matrix bit body as disclosed in one or more of U.S. Pat. No. 7,776,256, issued Aug. 17, 2010, to Smith et al. and U.S. Pat. No. 7,802,495, issued Sep. 28, 2010, to Oxford et al., the disclosure of each of which is incorporated herein in its entirety by this reference. Such an enhanced metal matrix bit body may comprise hard particles (e.g., ceramics such as oxides, nitrides, carbides, and borides) embedded within a continuous metal alloy matrix phase comprising a relatively high strength metal alloy (e.g., an alloy based on one or more of iron, nickel, cobalt, and titanium). As a non-limiting example, such an enhanced metal matrix bit body may comprise tungsten carbide particles embedded within an iron, cobalt, or nickel based alloy. As a further non-liming example, such an enhanced metal matrix bit body may comprise a ceramic metal composite material including ceramic particles disposed in a continuous metal matrix. However, it is to be appreciated that the bit body 10 may comprise other materials as well, and any bit body material is within the scope of the embodiments disclosed herein, including materials formed by rapid prototyping processes.
Removably disposed inside the outer barrel 4 may be an inner barrel assembly 16. The inner barrel assembly 16 may include an inner tube 18 adapted to receive and retain a core for subsequent transportation to the surface. The inner barrel assembly 16 may further include a core shoe (not shown in
As can be seen in
Referring to
A core catcher 46 may be carried by the core shoe 42 and may be housed within the central bore 44 of the core shoe 42. The core catcher 46 may comprise, for example, a wedging collet structure located within the core shoe 42. The core catcher 46 may be sized and shaped to enable the core 28 to pass through the core catcher 46 when traveling longitudinally upward into the inner tube 18. When the core barrel assembly 2 begins to back out of the wellbore, the outer surface of wedge-shaped portion 48 of the core catcher 46 comprising a number of circumferentially spaced collet fingers may interact with a tapered portion 50 of an inner surface 51 of the core shoe 42 to cause the collet fingers to constrict around and frictionally engage with the core 28, reducing (e.g., eliminating) the likelihood that the core 28 will exit the inner tube 18 after it has entered therein and enabling the core 28 to be fractured under tension from the formation from which the core 28 has been cut. The core 28 may then be retained in the inner tube 18 until the core 28 is transported to the surface for analysis. It is to be appreciated, however, that a core catcher is an optional feature of this disclosure and if a core catcher is used in conjunction with the disclosure it can be any type of core catcher known in the industry, such as but not limited to a spring-type catcher, collet catcher, flap catcher, full closure catcher, or any other appropriate catcher type known in the art. The catcher must at least partly interact with parts of the coring tool such as but not limited to the core shoe, the bit, a bit shank (not shown) to allow for catching the core when the coring tool is drawn.
An annular region 52 of the core barrel assembly 2 is located between the inner surface 40 of the bit body 10 and outer surfaces 54, 56 of the core shoe 42 and the inner tube 18, respectively. The annular region 52 forms a drilling fluid flow path extending longitudinally through the core barrel assembly 2 from a proximal end of the bit body 10 to the face discharge channel inlets 36. During a coring operation, drilling fluid is circulated under pressure into the annular region 52 such that drilling fluid can flow therefrom to the face surface 12 of the core bit 10, as described in more detail below. A flow diversion sleeve 60 may be disposed within the bit body 10. As shown in
With continued reference to
A first portion 42a of the core shoe 42 may substantially surround the wedge-shaped portion 48 of the core catcher 46. The first portion 42a of the core shoe 42 may be located longitudinally between a second portion 42b and a third portion 42c of the core shoe 42, wherein the second portion 42b is located longitudinally below the first portion 42a and extends toward the face surface 12 of the core bit 6, with the third portion 42c located longitudinally above the first portion 42a. Because the first portion 42a of the core shoe 42 may at least partially surround the wedge-shaped portion 48 of the core catcher 46, an outer surface 54a of the first portion 42a may have a diameter greater than a diameter of an outer surface 54b of the second portion 42b and a diameter of an outer surface 54c of the third portion 42c of the core shoe 42; however, it is to be appreciated that the diameter of the outer surface 54a of the first portion 42a may be substantially equivalent to the diameter of the outer surface 54c of the third portion 42c in other embodiments. Because the second portion 42b of the core shoe 42 may have a diameter less than that of the first portion 42a of the core shoe 42, the second portion 42b may be termed a “narrow” portion of the core shoe 42 relative to the first portion 42a thereof.
The flow split may be located at the second, narrow portion 42b of the core shoe 42. Accordingly, the outer surface 54b of the second portion 42b of the core shoe 42 may define at least a portion of the throat discharge channel 68. Such a portion of the throat discharge channel 68 may be located radially inward from at least a portion of the inner surface 61 of the sleeve 60. Furthermore, such a portion of the throat discharge channel 68 may be defined by at least a portion of the inner surface 61 of the sleeve 60. The flow split may be located at the narrow portion 42b of the core shoe 42 to provide more radial space for the throat discharge channel 68, the face discharge channels 34, and the regions of the bit body 10 surrounding these channels to maintain minimum wall thicknesses throughout the bit body 10 to prevent cracks or microfractures from forming in the bit body 10 during use. The minimum wall thickness of various portions of the bit body 10 necessary to prevent cracks or microfractures from forming therein depends upon numerous factors, including, by way of non-limiting example, material composition and design of the bit body 10, the method(s) of forming the bit body 10, the subterranean formation material in which the bit body 10 is used, and other operational constraints. In other embodiments (not shown), the flow split may be longitudinally located at the first portion 42a or the third portion 42c of the core shoe 42. Furthermore, in yet other embodiments (not shown), the diameter of the core shoe 42 may be substantially constant along the entire length of the core shoe 42.
Referring to
The sleeve 60 may be rigidly attached to an inner surface 40 of the bit body 10. The sleeve 60 may comprise an erosion-resistant material such as, by way of non-limiting example, cemented tungsten carbide. The bottom end 64 of the sleeve 60 may be beveled and may be affixed to a mating portion 76 of the inner surface 40 of the bit body 10. In the embodiment of
The outer surface 62 of the sleeve 60 may have a diameter less than a diameter of all portions of the inner surface 40 of the bit body 10 longitudinally upward of the longitudinal position at which the sleeve 60 is to be attached to the bit body 10 so that the sleeve 60 may be slid into place as a single, unitary body within the inner cavity 38 during assembly of the sleeve 60 within the bit body 10. Once the sleeve 60 is inserted into its final position where the bottom end 64 of the sleeve 60 abuts the mating portion 76 of the inner surface 40 of the bit body 10, the sleeve 60 may be rigidly affixed to the inner surface 40 of the bit body, as previously described.
In other embodiments (not shown), the outer surface 62 of the sleeve 60 may have a diameter greater than a diameter of at least a portion (i.e., a “narrow” portion) of the inner surface 40 of the bit body 10 longitudinally upward of the longitudinal position at which the sleeve 60 is to be attached to the bit body 10. In such embodiments, the sleeve 60 may comprise two or more separate circumferential sections, such as the three separate circumferential sections 60a, 60b, 60c shown in
The sleeve 60 may be configured to be replaceable. For example, if the sleeve 60 becomes damaged or worn during use, or if access is needed to the face discharge channels 34 or associated channel inlets 36, the sleeve 60 may be detached from the bit body 10. In embodiments where the outer surface 62 of the sleeve 60 has a diameter less than a diameter of all portions of the inner surface 40 of the bit body 10 longitudinally upward of the longitudinal position at which the sleeve 60 is to be attached to the bit body 10, the sleeve 60 may be removed as a single body. Alternatively, the sleeve 60 may be separated into smaller pieces prior to its removal from the cavity 38 of the bit body 10. In embodiments where the outer surface 62 of the sleeve 60 has a diameter greater than a diameter of a narrow portion of the inner surface 40 of the bit body 10 located longitudinally upward of the longitudinal position at which the sleeve 60 is to be attached to the bit body 10, such as shown in
The face discharge channels 34 may be formed prior to attachment of the sleeve 60 to the bit body 10. Thus, in the absence of the sleeve 60, the face discharge channel inlets 36 and the radially outer surfaces 80 of the face discharge channels 34 may be machined into the bit body 10 at least partially from the cavity 38 of the bit body 10 (enabling the formation of face discharge channels 34 having non-circular shapes when viewed in a lateral cross-sectional plane) via machining methods, such as cutting, milling, grinding, eroding, abrading or other formation methods, such as casting, centrifugal casting, additive manufacturing or 3D printing. For example, an entire longitudinal extent of the face discharge channels 34, extending from the associated channel inlets 36 to associated outlets 32 at the face surface 12 of the bit body 10, may be formed in the bit body 10 from the cavity 38 of the bit body 10. However, in other embodiments, a portion less than an entire longitudinal extent of the face discharge channels 34 may be formed in the bit body 10 from the cavity 38 of the bit body 10.
Additionally, the absence of the sleeve 60 during formation of the face discharge channel inlets 36 may allow easier access to the channel inlets 36 to be shaped non-cylindrically and/or have a varying diameter along a length thereof. For example, the face discharge channel inlets 36, similar to the face discharge channels 34 previously described in reference to
Additionally, because the sleeve 60 is replaceable and may be removed from the inner surface 40 of the bit body 10 after use, thereby providing access to the face discharge channels 34 from the cavity 38 of the bit body 10, the face discharge channels 34 and the associated channel inlets 36 may be repaired or otherwise modified after the core bit 6 has been used. For example, the face discharge channels 34 may be further processed and/or machined to reduce the surface friction of the surfaces thereof, to increase the TFA thereof, to change the transverse cross-sectional shape thereof, or to apply an erosion-resistant and/or friction-resistant coating to the surfaces thereof. The channel inlets 36 may be machined and or processed in a similar manner. Additionally, the channel inlets 36 may be machined to adjust the angle of approach of the channel inlets 36. Thus, the hydrodynamic efficiency of any of the flow split, the face discharge channels 34, and the throat discharge channel 68 may be repaired and/or improved after the core barrel assembly 2 has been used. Furthermore, while the replacement sleeve subsequently affixed to the inner surface 40 of the bit body 10 may be substantially identical to the original sleeve 60, in other embodiments, the replacement sleeve may differ from the original sleeve 60 in one or more properties, including, by way of non-limiting example, material composition, radial thickness, configuration of the upper end 63 forming part of the face discharge channel inlets 36, or surface features, such as those disclosed in more detail below. Thus, properties of the face discharge channels 34, the throat discharge channel 68, and the face discharge channel inlets 36 may be adjusted merely by replacing the sleeve 60. The choice of the sleeve 60 properties may be based on the experience with the sleeve that is to be replaced or the formation that was engaged or that is expected to be engaged downhole.
In the embodiment shown in
With continued reference to
It is to be appreciated that
Furthermore, in other embodiments, the series of consecutive TFA changes may be provided by forming a plurality of protrusions extending radially inward from the inner surface 61 of the sleeve 60 and/or radially outward from the outer surface 54b of the core shoe 42 in the throat discharge channel 68. Such protrusions may be effectively configured as an inverse of any of the “recesses” 86-86d previously described, and may have other configurations as well. In yet other embodiments, the series of consecutive TFA changes may include a combination of recesses 86 and protrusions formed on or in the inner surface 61 of the sleeve 60 and/or the outer surface 54b of the core shoe 42 in the throat discharge channel 68. Additionally, at least one of the recesses 86 and/or protrusions may vary in shape, form, orientation and/or configuration from at least one other recess 86 and/or protrusion.
It is to be appreciated that the throat discharge channel 68 may include any number of TFA changes provided by recesses 86 and/or protrusions formed on and/or in the inner surface 61 of the sleeve 60 and the outer surface 54b of the core shoe 42 located within the throat discharge channel 68. For example, in the embodiment shown in
It is to be appreciated that, while
In embodiments where the sleeve 60 is omitted, the face discharge channels 34 and the associated channel inlets 36, may be formed to have non-circular shapes in a transverse cross-sectional plane in a manner alternative to being machined from the cavity 38 of the bit body 10. By way of non-limiting example, for metal bit bodies, such as steel bit bodies, the bit body may be formed by a centrifugal die casting process, as set forth in U.S. Patent Publication No. 2013/0146366 A1, published Jun. 6, 2013, to Cheng et al. In such processes, metal material may be introduced into a die that defines the shape of the bit body to be formed, including the face discharge channels 34 and associated channel inlets 36. The die is heated and rotated to generate centrifugal forces on the heated metal to cause the metal to conform to the die shape. The die is subsequently cooled, and the formed bit body is removed from the die. Alternatively, for steel bit bodies, the face discharge channels having non-circular shapes in a lateral plane may be machined from the face surface 12 of the bit body 10. For metal-matrix bit bodies, which may be extremely difficult, if not virtually impossible, to machine in a practical sense, the bit body having face discharge channels with non-circular shapes in a lateral cross-sectional plane may be formed by placing hard particulate material, such as tungsten carbide, within a graphite mold and infiltrated with a binder, such as a copper alloy, as also set forth in Cheng. Cast resin-coated sand, graphite displacements or, in some instances, tungsten carbide particles in a flexible polymeric binder, may be employed to define topographic features of the bit. A machinable blank or blanks may be disposed within the bit mold to define the finished shape of the face discharge channels 34 and channel inlets 36 thereof prior to infiltration of the hard particulate material. Such blanks may comprise graphite, steel, or other materials. After hardening of the infiltrant, the blank may be machined away, leaving the face discharge channels 34 and associated channel inlets 36 shaped as desired. Other methods of forming the non-circular shaped face discharge channels 34 and associated channel inlets 36 are also possible in embodiments omitting the sleeve 60. It is to be appreciated that such additional forming methods may be utilized to form bit bodies 10 in embodiments where the sleeve 60 is included, in additional to embodiments where the sleeve 60 is omitted.
A proximal portion of the face discharge channel inlet 136 may be located at a first longitudinal location P1 longitudinally downward of the first portion 42a of the core shoe 42 housing the core catcher 46. A diameter of the inner surface 40 of the bit body 10 may gradually increase in a longitudinal direction toward the face surface 12 of the bit body 10 to a second longitudinal location P2, beyond which extends a region 150 of the bit body 10 where the diameter of the inner surface 40 of the bit body 10 remains substantially constant. The radially outer part of the region 150 of the bit body 10 forms the radially outer part of the annular, ring-shaped face discharge channel 134. The annular, ring-shaped face discharge channel 134 effectively terminates at a third longitudinal location P3 proximate the face surface 12 of the bit body 10. The outer contour of the annular, ring-shaped face discharge channel 134 may be formed prior to attachment of the sleeve 60 to the bit body 10. Thus, in the absence of the sleeve 60, the annular, ring-shaped face discharge channel 134 may be machined into the bit body 10 at least partially from the cavity 38 of the bit body 10 via machining methods, such as cutting, milling, turning, grinding, electrochemical machining, eroding, abrading or other formation methods, such as casting, centrifugal casting, additive manufacturing or 3D printing.
A mating portion 76 of the inner surface 40 of the bit body 10 may be located proximate the third longitudinal location P3 and may be configured to receive the bottom end 64 of the sleeve 60, as previously described. The bottom end 64 of the sleeve 60 may be rigidly attached to the mating portion 76 of the inner surface 40 of the bit body 10 by one or more of brazing, shrink fitting, adhesives, or mechanical fastening features, as previously described. The sleeve 60 may also include a torque transmitting feature, such as circumferentially spaced keys on the bottom end 64 of the sleeve 60 extending into like-sized and spaced recesses in the mating portion 76 of the inner surface 40 of the bit body 10. Likewise, torque transmitting elements may be included into the outer surface 62 of the sleeve 60. The sleeve 60 may form a barrier between the annular, ring-shaped face discharge channel 134 located radially outward of the sleeve 60 and the throat discharge channel 68 located radially inward of the sleeve 60, as previously described. A radially inner surface 61 of the sleeve 60 may define at least a portion of a boundary profile 70 of the throat discharge channel 68. Additionally, a radially outer surface 62 of the sleeve 60 may define a radially inner surface 178 of the annular, ring-shaped face discharge channel 134. A longitudinal upper-most end 63 of the sleeve 60 may at least partially define the inlet 136 of the face discharge channel 134. In other embodiments, the sleeve 60 may include fluid passages extending therethrough, as previously described, allowing drilling fluid to flow through the sleeve 60 and into the ring-shaped face discharge channel 134.
The outer surface 62 of the sleeve 60 may have a diameter less than a diameter of all portions of the inner surface 40 of the bit body 10 longitudinally upward of the second longitudinal location of the bit body 10 so that the sleeve 60 may be slid into place as a single, unitary body within the cavity 38 during assembly of the sleeve 60 within the bit body 10. Alternatively, the outer surface 62 of the sleeve 60 may have a diameter greater than a diameter of at least a portion of the inner surface 40 of the bit body 10 longitudinally upward of the second longitudinal location P2 of the bit body 10. In such embodiments, the sleeve 60 may comprise two or more separate circumferential sections that may be assembled in the bit body 10 and disassembled therefrom, as previously described in relation to
The annular, ring-shaped face discharge channel 134 may be in fluid communication with the face discharge outlets 132. The face discharge outlets 132 may be milled or bored from the face surface 12 of the bit body 10 until the face discharge outlets 132 intercept the annular, ring-shaped face discharge channel 134. It is to be appreciated that the face discharge outlets 132 may be formed by other methods, such as cutting, grinding, casting, centrifugal casting, additive manufacturing, 3D printing, or powder metallurgical methods. The face discharge outlets 132 may intercept the face discharge channel 134 at an angle, as shown in
With continued reference to
It is to be appreciated that the sleeves 60 and or the core shoes 42 of
The various embodiments of the core bit 6 previously described may include many other features not shown in the figures or described in relation thereto, as some aspects of the core bit 6 may have been omitted from the text and figures for clarity and ease of understanding. Therefore, it is to be understood that the core bit 6 may include many features in addition to those shown in the figures. Furthermore, it is to be further understood that the core bit 6 may not contain all of the features herein described.
Additional, nonlimiting embodiments within the scope of this disclosure include:
A coring bit for use on a coring tool for extracting a sample of subterranean formation from a wellbore, comprising: a bit body having a cavity, wherein a throat portion of the cavity extends into the bit body from a face of the bit body; and a sleeve disposed within the cavity of the bit body, the sleeve configured to separate at least one face discharge channel and a throat discharge channel, the at least one face discharge channel located radially outward of the sleeve, the throat discharge channel located radially inward of the sleeve.
The coring bit of Embodiment 1, further comprising a coring shoe disposed in the cavity of the bit body.
The coring bit of Embodiment 1 or Embodiment 2, wherein the sleeve comprises two or more parts.
The coring bit of any one of Embodiments 1 through 3, wherein the sleeve defines at least one recess in a radially inner surface of the sleeve, the at least one recess providing the throat discharge channel with zones of higher and lower flow resistance.
The coring bit of any one of Embodiments 1 through 4, wherein the throat discharge channel comprises a first region and a second region, wherein the second region has a total flow area higher than a total flow area of the first region.
The coring bit of any one of Embodiments 1 through 5, further comprising one or more guide blocks affixed to an inner surface of the bit body within the cavity, the one or more guide blocks configured to guide the sleeve into place during insertion of the sleeve into the cavity of the bit body or to support the sleeve during operation of the coring bit.
The coring bit of any one of Embodiments 1 through 6, wherein the sleeve defines one or more fluid passages extending through the sleeve.
The coring bit of any one of Embodiments 1 through 7, wherein at least a portion of a length of the at least one face discharge channel has non-circular cross-sectional shape.
The coring bit of Embodiment 8, wherein the portion of the length of the at least one face discharge channel having a non-circular cross-sectional shape comprises about 40% or more of the length of the at least one face discharge channel.
The coring bit of Embodiment 8 or Embodiment 9, wherein a total circumferential dimension of the portion of the at least one face discharge channel subtends an angle of at least about 72 degrees about a longitudinal axis of the bit body in a plane transverse to the longitudinal axis of the bit body.
The coring bit of any one of Embodiments 8 through 10, wherein a total circumferential dimension of the portion of the at least one face discharge channel subtends an angle of at least about 108 degrees about a longitudinal axis of the bit body in a plane transverse to the longitudinal axis of the bit body.
The coring bit of any one of Embodiments 8 through 11, wherein a total circumferential dimension of the portion of the at least one face discharge channel subtends an angle of at least about 144 degrees about a longitudinal axis of the bit body in a plane transverse to the longitudinal axis of the bit body.
A method of repairing a coring tool for extracting a sample of subterranean formation from a wellbore, the method comprising: removing a sleeve from a cavity of a bit body of the coring tool, the sleeve configured to separate at least one face discharge channel and a throat discharge channel during operation of the coring tool, the at least one face discharge channel located radially outward of the sleeve, the throat discharge channel located radially inward of the sleeve.
The method of Embodiment 13, further comprising: repairing a radially outer surface of the at least one face discharge channel after removing the sleeve; and installing a replacement sleeve into the cavity of the bit body, wherein the replacement sleeve is one of the removed sleeve, a repaired sleeve, and a new sleeve.
The method of Embodiment 14, wherein repairing the radially outer surface of the at least one face discharge channel comprises forming at least a portion of the at least one face discharge channel by one or more of a cutting, milling, turning, grinding, eroding, polishing, additive manufacturing, 3D printing, and casting process.
The method of any one of Embodiments 13 through 15, wherein the sleeve comprises two or more parts.
The method of any one of Embodiments 14 through 16, further comprising installing at least one guide block in the cavity of the bit body prior to installing the replacement sleeve into the cavity of the bit body.
The method of any one of Embodiments 14 through 17, further comprising selecting the replacement sleeve according to one or more of a downhole subterranean earth formation, drilling fluid composition, and a drilling fluid flow rate expected during operation of the coring tool.
The method of any one of Embodiments 13 through 18, wherein a total circumferential dimension of the at least one face discharge channel subtends an angle of at least about 108 degrees about a longitudinal axis of the bit body in a plane transverse to the longitudinal axis of the bit body.
The method of Embodiment 13, further comprising: forming an additional face discharge channel in an inner surface in the bit body after removing the sleeve by one or more of a cutting, milling, turning, grinding, eroding, polishing, additive manufacturing, 3D printing, and casting process; and installing a replacement sleeve into the cavity of the bit body, wherein the replacement sleeve is one of a repaired sleeve and a new sleeve.
While certain illustrative embodiments have been described in connection with the figures, those of ordinary skill in the art will recognize and appreciate that the scope of this disclosure is not limited to those embodiments explicitly shown and described herein. Rather, many additions, deletions, and modifications to the embodiments described herein may be made to produce embodiments within the scope of this disclosure, such as those hereinafter claimed, including legal equivalents. In addition, features from one disclosed embodiment may be combined with features of another disclosed embodiment while still being within the scope of this disclosure, as contemplated by the inventors.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2068704 | Powell | Jan 1937 | A |
| 4551758 | Masunaga | Nov 1985 | A |
| 4981183 | Tibbitts | Jan 1991 | A |
| 5460230 | Dekoster | Oct 1995 | A |
| 5568838 | Struthers et al. | Oct 1996 | A |
| 6182760 | Phelps | Feb 2001 | B1 |
| 6394196 | Fanuel et al. | May 2002 | B1 |
| 7055626 | Wells et al. | Jun 2006 | B2 |
| 7776256 | Smith et al. | Aug 2010 | B2 |
| 7802495 | Oxford et al. | Sep 2010 | B2 |
| 8459381 | Pearce et al. | Jun 2013 | B2 |
| 20030173116 | Wells | Sep 2003 | A1 |
| 20060169496 | Puymbroeck et al. | Aug 2006 | A1 |
| 20070261886 | Wilson et al. | Nov 2007 | A1 |
| 20100089660 | Pearce et al. | Apr 2010 | A1 |
| 20110162892 | Oothoudt | Jul 2011 | A1 |
| 20110186288 | Braddick | Aug 2011 | A1 |
| 20130146366 | Cheng et al. | Jun 2013 | A1 |
| 20140216826 | Pearce et al. | Aug 2014 | A1 |
| 20140360792 | Azar | Dec 2014 | A1 |
| 20150021096 | Wesemeier et al. | Jan 2015 | A1 |
| 20150267492 | Broussard, Jr. | Sep 2015 | A1 |
| Entry |
|---|
| Uhlenberg et al., U.S. Appl. No. 14/274,495 entitled Coring Tools and Related Methods, filed May 9, 2014. |
| International Search Report for International Application No. PCT/US2016/020974, dated Jun. 15, 2016, 3 pages. |
| International Written Opinion for International Application No. PCT/US2016/020974, dated Jun. 15, 2016, 9 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20160258223 A1 | Sep 2016 | US |
