Patent Grant
10597946
In drilling a borehole, such as for the recovery of hydrocarbons or for other applications, it is conventional practice to connect a drill bit on the lower end of an assembly of drill pipe sections that are connected end-to-end so as to form a drill string. The bit is rotated by rotating the drill string at the surface or by actuation of downhole motors or turbines, or by both methods. With weight applied to the drill string, the rotating bit engages the earthen formation causing the bit to cut through the formation material by either abrasion, fracturing, or shearing action, or through a combination of these and/or other cutting methods, thereby forming a borehole.
Many different types of drill bits have been developed and found useful in drilling such boreholes. Two common types of drill bits are roller cone bits and fixed cutter (or rotary drag) bits. Most fixed cutter bit designs include a plurality of blades angularly spaced about the bit face. The blades project radially outward from the bit body and form flow channels therebetween. In addition, cutting elements are typically grouped and mounted on several blades in radially extending rows. The configuration or layout of the cutting elements on the blades may vary.
The cutting elements on the blades of a fixed cutter bit are typically formed of extremely hard materials. In atypical fixed cutter bit, each cutting element includes an elongate and generally cylindrical tungsten carbide substrate that is received and secured in a pocket formed in the surface of one of the blades. The cutting elements typically include a hard cutting layer of polycrystalline diamond (PCD) or other superabrasive materials such as thermally stable diamond or polycrystalline cubic boron nitride. These cutting elements are designed to shear formations that range from soft to medium hard. For convenience, as used herein, reference to “PDC bit” or “PDC cutters” refers to a fixed cutter bit or cutting element employing a hard cutting layer of polycrystalline diamond or other superabrasive materials.
Without regard to the type of bit, the cost of drilling a borehole is proportional to the length of time it takes to drill the borehole to the desired depth and location. The drilling time is affected by the number of times the drill bit is changed in order to reach the targeted formation, as each time the bit is changed, the entire drill string, which may be miles long, is retrieved from the borehole section by section. Once the drill string has been retrieved and the new bit installed, the bit is lowered to the bottom of the borehole on the drill string, which again is constructed section by section. This process, known as a trip of the drill string, often requires considerable time, effort, and expense.
The length of time that a drill bit may be used before it is changed depends upon its rate of penetration (ROP), as well as its durability or ability to maintain a high or acceptable ROP. Specifically, ROP is the rate that a drill bit penetrates a given subterranean formation. Drill bit designs are modified to improve ROP in specific formations so as to reduce drilling time, and thus, cost.
Once a desired formation is reached in the borehole, a core sample of the formation may be extracted for analysis. A hollow coring bit is often employed to extract a core sample from the formation. Once the core sample has been transported from the borehole to the surface, the sample may be used to analyze and test, for example, permeability, porosity, composition, or other geological properties of the formation. Conventional coring methods require retrieval of the drill string from the borehole, replacement of the drill bit with a coring bit, and lowering of the coring bit into the borehole on the drill string in order to retrieve a core sample, which is then removed to the surface for analysis.
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.
In one aspect, embodiments disclosed herein relate to a drill bit that includes a bit body having a bit centerline and a bit face, a plurality of blades extending radially along the bit face including a coring blade, a plurality of cutting elements disposed on the blades, and a non-planar insert embedded in the bit body proximate to the bit centerline. One of the plurality of cutting elements may be a first cutting element on the coring blade at a first radial position from the bit centerline, and at least a portion of the coring blade may be radially outward from a most radially interior cutting part of the first cutting element.
In another aspect, embodiments disclosed herein relate to a drill bit for obtaining core sample fragments from a subterranean formation that includes a bit body having a bit centerline and a bit face, a plurality of blades extending radially along the bit face, at least one of the blades being a coring blade that has a radially interior surface, and a plurality of cutting elements disposed on the plurality of blades. At least one of the cutting elements may be a first cutting element located at the first radial position from the bit centerline, and at least one of the cutting elements may be a core trimming cutting element on the coring blade on the radially interior surface axially spaced from the first cutting element and at a greater radial distance from the bit centerline than the first radial position. A non-planar insert may be affixed to the bit body proximate the bit centerline
In yet another aspect, embodiments of the present disclosure relate to a method of obtaining core sample fragments from a subterranean formation during directional drilling that includes coupling a drill bit to a steerable tool at a lower end of a drill string, rotating the drill string to engage and cut the formation, thereby creating a wellbore, tilting the drill bit via the steerable tool to drill the formation at a non-vertical direction, and using a coring feature of the drill bit to weaken the core sample fragment in order to cause the core sample fragment to break away from the formation after the core sample fragment reaches a length. The drill bit used in the method may include a bit body having a bit centerline and a bit face, a plurality of blades extending radially along the bit face, at least one of the plurality of blades being a coring blade having a continuously angled surface extending from the bit face to a first radial position from the bit centerline, a plurality of cutting elements on the plurality of blades, one of the plurality of cutting elements being a first cutting element on the coring blade at the first radial position from the bit centerline. The drill bit may also include a gage surface extending from the plurality of blades at the radially outermost region of the drill bit, each gage surface being angled toward the bit centerline. The drill bit may also include a conical insert embedded in the bit body at the bit centerline or between the bit centerline and the first radial position. The continuously angled surface may have an angle that is about the same as the angle of the angled gage surface.
Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims.
Embodiments of the present disclosure will be described below with reference to the figures. In one aspect, embodiments disclosed herein relate to use of coring blades in PDC fixed cutter drill bits. In particular, embodiments disclosed herein relate to drill bits having coring blades having an angled surface proximate the bit centerline and/or interior cutting elements having radial offset for extracting core samples during directional drilling. Directional, or non-vertical, drilling angles are achieved by connecting a steerable tool between the drill bit and a lower end of a drill string. Directional drilling may involve tilting the drill bit several degrees from vertical in order to reach a targeted drilling region. When directionally drilling with a drill bit (not a coring bit) that includes a coring blade to extract small core samples, the titling that occurs may cause premature extraction of a core sample due to induced forces on the core sample from the coring blade. Thus, embodiments of the present disclosure are directed to variations on the radially interior surface of coring blade(s) so as to allow for the directional drilling without negatively impacting the core sample being formed. Other embodiments disclosed herein relate to fixed cutter drill bits containing conical or other non-planar cutting elements, including the placement of such cutting elements on a bit and variations on the cutting elements that may be used to optimize core sampling.
Referring to
The cutting structure 15 is on face 20 of PDC bit 10. The cutting structure 15 includes a plurality of angularly spaced-apart primary blades 31, 32, 33, and secondary blades 34, 35, 36, each of which extends from bit face 20. The primary blades 31, 32, 33 and the secondary blades 34, 35, 36 extend generally radially along the bit face 20 and then axially along a portion of the periphery of the PDC bit 10. The secondary blades 34, 35, 36 extend radially along the bit face 20 from a position that is distal the bit axis 11 toward the periphery of the PDC bit 10. Thus, as used herein, secondary blade may be used to refer to a blade that begins at some distance from the bit axis and extends generally radially along the bit face to the periphery of the bit. The primary blades 31, 32, 33 and the secondary blades 34, 35, 36 are separated by drilling fluid flow courses 19.
Each primary blade 31, 32, 33 includes blade tops 42 for mounting a plurality of cutting elements, and each secondary blade 34, 35, 36 includes blade tops 52 for mounting a plurality of cutting elements. In particular, cutting elements 40, each having a cutting face 44, are mounted in pockets formed in blade tops 42, 52 of each primary blade 31, 32, 33 and each secondary blade 34, 35, 36, respectively. Cutting elements 40 are arranged adjacent one another in a radially extending row proximal the leading edge of each primary blade 31, 32, 33 and each secondary blade 34, 35, 36. Each cutting face 44 has an outermost cutting tip 44a furthest from blade tops 42, 52 to which cutting element 40 is mounted.
Referring now to
The composite blade profile 39 (most clearly shown in the right half of PDC bit 10 in
The axially lowermost point of the convex shoulder region 25 and the composite blade profile 39 defines a blade profile nose 27. At the blade profile nose 27, the slope of a tangent line 27a to the convex shoulder region 25 and the composite blade profile 39 is zero. Thus, as used herein, the term “blade profile nose” refers to the point along a convex region of a composite blade profile of a bit in rotated profile view at which the slope of a tangent to the composite blade profile is zero. For most conventional fixed cutter bits, the composite blade profile includes a convex shoulder region (e.g., convex shoulder region 25), and a blade profile nose (e.g., nose 27). As shown in
Referring to
When the PDC bit 100 is secured to the drill string, rotating the drill string causes the PDC bit 100 to rotate and penetrate and cut through a subterranean formation using a plurality of cutting elements 125, which are described in further detail below. As the PDC bit 100 penetrates and cuts through the subterranean formation, a wellbore is formed.
As shown in
As further shown in
According to one or more embodiments of the present disclosure, the PDC bit 100 includes a non-planar (e.g., conical) insert 131 embedded in the bit body 110 on or close to the bit centerline 101. As described in further detail below, the conical insert 131 works with the coring blade 123 to cause a core sample fragment 150 to break away from the formation during drilling.
As further shown in
In accordance with one or more embodiments of the present disclosure, the first radial position R1 is located at some distance away from the bit centerline 101 to allow for the formation of core sample fragment 150. According to one or more embodiments of the present disclosure, the first radial position R1 may be distanced from the bit centerline 101 at a distance in a range of 0.05 times the diameter of the PDC bit 100 to 0.25 times the diameter of the PDC bit 100. As understood by one of ordinary skill in the art, the first radial position R1 may be located at other distances away from bit centerline 101, depending on the desired size of the core sample fragment, without departing from the scope of the present disclosure.
As further shown in
In accordance with one or more embodiments of the present disclosure, the continuously angled surface 127 may be oriented such that the continuously angled surface 127 is sloped from the first cutter 126 at a radially outwardly opening angle α ranging from 0° to 20° (e.g., 0° to 15°, 0° to 10°, or 0° to 6°) with respect to a line parallel to the bit centerline 101. In other words, the continuously angled surface 127 slopes upwardly and outwardly as it extends from the first cutter 126 at the first radial position R1 to the bit face 111. At least a portion of the coring blade 123 is radially outward from a most radially interior cutting part of the first cutter 126. The slope of the continuously angled surface 127, angle α, allows for the formation and extraction of core sample fragment 150 when the PDC bit 100 is tilted, for example, during directional drilling. For example, when the continuously angled surface 127 is oriented such that the continuously angled surface 127 slopes upwardly and outwardly from the first cutter 126 at the first radial position R1 to the bit face 111 at an angle α from the bit centerline 101, the PDC bit 100 may tilt up to an angle α from vertical, to maintain the formation and extraction of the core sample fragment 150 at the desired core sample fragment length.
In some embodiments, the continuously angled surface 127 may slope upwardly and outwardly from first cutter 126 at the first radial position R1 to the bit face 111 such that the angle α may have a lower limit of any of at least 0.5°, 1°, 2°, or 3° with respect to a line parallel to bit centerline 101, and an upper limit of any of 2°, 3°, 4°, 5°, 6°, 7°, 8°, 9°, or 10° with respect to a line parallel to the bit centerline 101, where any lower limit can be used in combination with any upper limit. The present disclosure is not limited, however, and may include other angles, depending on the build rate angles used in the steerable device (not shown) for directional drilling. For example, in one or more embodiments the angle α may be at least that of the build angle selected for the directional drilling job. Embodiments including more than one coring blade 123 may be arranged such that each continuously angled surface 127 of coring blade 123 has the same angle α, or arranged such that each continuously angled surface 127 of coring blade 123 has a different angle α from each other.
As shown, according to one or more embodiments of the present disclosure, the conical insert 131 may be a rigid cutting element configured in the general shape of a cone. However, the shape of the conical insert 131 is not intended to be limiting, and the conical insert 131 may be configured in a different shape than a cone. As understood by one of ordinary skill in the art, according to one or more embodiments of the present disclosure, the conical insert 131 may in fact be replaced with any insert have any shape that acts to break up the core sample fragment 150 that comes in contact therewith, including other cutting elements having non-planar cutting ends, as described below.
According to one or more embodiments of the present disclosure, the conical insert 131 may be formed as an integral element of the bit body 110, or as a non-integral insert made of a polycrystalline superabrasive material. According to one or more embodiments of the present disclosure, the conical insert 131 is a non-integral insert that includes a substrate (such as a cemented tungsten carbide substrate) that interfaces with a diamond layer made of a polycrystalline superabrasive material, which may include, e.g., polycrystalline diamond, polycrystalline cubic boron nitride, or thermally stable polycrystalline diamond. According to one or more embodiments of the present disclosure, a diamond layer forms a conical diamond working surface of the conical insert 131, and the substrate forms a base of the conical insert 131. Without departing from the scope of the present disclosure, additional shapes, structures, compositions, and dimensions of conical insert 131 may be employed, such as those described in U.S. Patent Pub. No. 2013/0020134, which is herein incorporated by reference in its entirety.
According to one or more embodiments of the present disclosure, the conical insert 131 embedded proximate to the bit centerline 101 exerts a central load on the end of the core sample fragment 150 that is closest to the apex of the conical insert 131. The central load exerted by the conical insert 131 causes the core sample fragment 150 to fracture or crack. As a result of this central load and because the conical insert 131 is disposed on or proximate to the bit centerline 101, the core sample fragment 150 may break into two halves, which may or may not be substantially equal in length and width.
After the core sample fragment 150 is broken away from formation in accordance with one or more embodiments of the present disclosure, bit hydraulics help the newly extracted core sample fragment 150 to be relayed and/or directed toward flow courses (not shown) between the plurality of blades 121 for exit of PDC bit 100. According to one or more embodiments of the present disclosure, from a flow course, core sample fragment 150 is transported to the surface of the formation via an annulus between the wellbore and the drill string.
Referring now to
As further shown in
In accordance with one or more embodiments of the present disclosure, one of the plurality of cutting elements 125 is a core trimming cutter (or interior cutting element) 236 disposed on the substantially vertical surface 227. In such embodiments, as shown in
In a particular embodiment, the first cutter 226 and the core trimming cutter 236 may be arranged such that the radial offset 251 may have a lower limit of any of at least 0.02, 0.03, 0.04, or 0.05 inch (or at least 0.51, 0.76, 1.02, or 1.27 mm), and an upper limit of any of 0.03, 0.04, 0.05, 0.06, 0.1, or 0.5 inch (or of any of 0.76, 1.02, 1.27, 1.52, 2.54, or 12.7 mm), where any lower limit can be used in combination with any upper limit. Embodiments including more than one coring blade 123 may be arranged such that the core trimming cutters 236 on each coring blade 123 has the same radial offset 251, or arranged such that the core trimming cutters 236 on each coring blade 123 has a different radial offset 251 from each other. Further, the radial offset of the substantially vertical surface 227 may be the same or different on each coring blade 123. In such embodiments, there also exists an axial offset 253 between the first cutter 226 and core trimming cutter 236. The axial offset 253 may be equal to the radius of the first cutter 226 plus the radius of the core trimming cutter 236 plus a spacing ranging from 0.05 inch to 1 inch (e.g., 0.1 to 0.8 inch or 0.4 to 0.6 inch).
Still referring to
As shown in
Referring to
Referring back to
When considering the orientation of cutting elements having non-planar cutting ends, in addition to the vertical or lateral orientation of the cutting element body, the geometry of the non-planar cutting end also affects how and the angle at which the non-planar cutting element strikes the formation. Specifically, in addition to the back rake affecting the aggressiveness of the cutting end-formation interaction, the cutting end geometry (specifically, the apex angle and radius of curvature) affect the aggressiveness that the non-planar cutting element attacks the formation. In the context of a non-planar cutting element, as shown in
In addition to the orientation of the axis with respect to the formation, the aggressiveness of non-planar cutting elements may also be dependent on the apex angle or specifically, the angle between the formation and the leading portion of the non-planar cutting element. In some embodiments, a leading line of a non-planar cutting surface may be determined to be the firstmost points at each axial point along the side surface of the non-planar cutting end surface as the bit rotates. Said in another way, a cross-section may be taken of a non-planar cutting element along a plane in the direction 350 of the rotation of the cutting tool, as shown in
Referring to
Cutting elements that cut formation material at the core sidewall or at both the bottom hole and the core sidewall may have a back rake angle measured with respect to the surface on which the cutting element is disposed and/or with respect to the direction of rotation of the cutting tool on which the cutting element is disposed. For example, in some embodiments, a back rake may refer to a direction of rotation of the cutting element along a plane intersecting the central axis of the cutting element and normal to the surface on which the cutting element is disposed, such that a back rake refers to a rotational direction exposing a relatively larger portion of the cutting end of the cutting element (negative back rake) or exposing a relatively larger portion of a base end (opposite the cutting end) of the cutting element (positive back rake). In other words, a back rake angle may refer to the rotation of the cutting end of a cutting element away from the surface on which it is disposed.
Further, cutting elements of the present disclosure may be disposed on a cutting tool blade at a side rake, where the side rake may be defined as the angle between the cutting face and a radial plane of the cutting tool (x-z plane), as illustrated in
As discussed, the PDC bit 100 may tilt at an angle α from vertical, for example, during directional drilling. Referring to
As mentioned above, several of the illustrated embodiments show the use of conical cutting elements. However, the present disclosure is not so limited. Rather, in each instance where a conical cutting element is described and/or illustrated, it is also intended that cutting element having other shaped non-planar cutting ends may be used. Non-planar cutting elements refers to those cutting elements having a non-planar cutting face, such as a generally pointed cutting end, e.g., having a cutting end terminating in an apex, which may include, for example, cutting elements having a conical cutting end (shown in
The apex of a non-planar cutting element may have curvature, including a radius of curvature. In one or more embodiments, the radius of curvature may range from about 0.050 inch to 0.16 inch. One or more other embodiments may use a radius of curvature ranging from a lower limit of any of 0.05 inch, 0.06 inch, 0.075 inch, 0.085 inch, or 0.1 inch to an upper limit of any of 0.075 inch, 0.085 inch, 0.095 inch, 0.1 inch, 0.11 inch, 0.125 inch, or 0.16 inch, where any lower limit can be used with any upper limit. In some embodiments, the curvature may comprise a variable radius of curvature, a portion of a parabola, a portion of a hyperbola, a portion of a catenary, or a parametric spline. In one or more embodiments, the cone angle of the non-planar cutting element may range from 60° to 120°. However, the non-planar cutting element may be sharp or have a flat top.
Further, in one or more embodiments, the non-planar cutting elements may include any pointed or otherwise non-planar cutting end shape having an cutting end extending above a grip or base region, where the cutting end extends a height that is at least 0.25 times the diameter of the cutting element, or at least 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8 times the diameter in one or more other embodiments. As used herein, a cutting end may include the side surface and rounded apex forming the non-planar working surface. According to some embodiments, a cutting end may be formed of an ultrahard material, such as diamond, diamond composite, polycrystalline diamond, thermally stable polycrystalline diamond (formed either by treatment of polycrystalline diamond formed from a metal catalyst such as cobalt or polycrystalline diamond formed with a metal having a lower coefficient of thermal expansion than cobalt), polycrystalline cubic boron nitride, or combinations of ultra-hard material, which may be attached to or formed on a substrate forming the grip or base region.
For example, as shown in
The interface 606, 706, 806 between diamond layer 602, 702, 802 and substrate 604, 704, 804 may be non-planar or non-uniform, for example, to aid in reducing incidents of delamination of the diamond layer 602, 702, 802 from substrate 604, 704, 804 when in operation and to improve the strength and impact resistance of the element. The interface may include one or more convex or concave portions, as known in the art of non-planar interfaces. Additionally, use of some non-planar interfaces may allow for greater thickness in the diamond layer in the tip region of the layer. Further, it may be desirable to create the interface geometry such that the diamond layer is thickest at a zone that encompasses the primary contact zone between the diamond enhanced element and the formation. Additional shapes and interfaces that may be used for the diamond enhanced elements of the present disclosure include those described in U.S. Patent Publication No. 2008/0035380, the entirety of which is incorporated by reference. In some embodiments, non-planar cutting elements may have a planar interface between an ultra-hard material body forming the non-planar cutting end and a substrate. In one or more embodiments, the diamond layer 602, 702, 802 may have a thickness of 0.100 to 0.500 inch (2.54 to 12.7 mm) from the apex to the central region of the interface with the substrate, and in or more particular embodiments, such thickness may range from 0.125 to 0.275 inch (3.175 to 6.985 mm). However, other sizes and thicknesses may also be used.
As used herein, a non-planar cutting end of a non-planar cutting element refers to the pointed end of the non-planar cutting element and is defined by the non-planar working surface, while a grip region refers to the remaining region of the non-planar cutting element axially adjacent the non-planar cutting end. As shown in
Further, according to embodiments of the present disclosure, a non-planar cutting element may include a substantially cylindrical grip region and a pointed non-planar cutting end. In other embodiments, a non-planar cutting element may include a grip region with a non-cylindrical shape. For example, a grip region may have a curved base surface or a tapered base end, where the base surface and base end are opposite the cutting end of the cutting element. In some embodiments, a grip region may include the region of the non-planar cutting element defined by one or more outer side surfaces substantially parallel with a central longitudinal axis of the non-planar cutting element. For example, as shown in
Methods of obtaining core sample fragments from a subterranean formation during directional drilling may include coupling a drill bit, as described above, to a steerable tool at a lower end of a drill string. For example, the bit may have a threaded pin end capable of threadedly connecting to a steerable tool used for directional drilling. A drill bit may include a coring feature, for example, coring blades having an angled surface proximate the bit centerline and/or interior cutting elements having radial offset for extracting core samples during directional drilling. The drill string may be rotated to engage the drill bit with the subterranean formation, cutting and creating a wellbore. The steerable tool may introduce a non-vertical angle to the drill string and tilt the drill bit to drill the formation at a non-vertical direction, or directionally drill. As the drill bit rotates, the coring feature of the drill bit may be used to weaken a core sample fragment and cause the core sample fragment to break away from the formation after the core sample fragment reaches a length (e.g., reaches a set or predetermined length, e.g., the distance between where the first cutting element engages the formation and the apex of the insert 131, however, any suitable desired length may be used). Hydraulic forces from the bit and drilling fluid may direct the extracted core sample fragment toward flow courses between a plurality of blades in the drill bit. According to one or more embodiments of the present disclosure, from a flow course, a core sample fragment is transported to the surface of the formation via an annulus that is formed between the wellbore and the drill string.
The articles “a,” “an,” and “the” are intended to mean that there are one or more of the elements in the preceding descriptions. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. Additionally, 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. Numbers, percentages, ratios, or other values stated herein are intended to include that value, and also other values that are “about” 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.
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.
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.
This application is a continuation of U.S. patent application Ser. No. 14/956,897, filed Dec. 2, 2015, which claims the benefit of and priority to U.S. Patent Application No. 62/095,705 filed on Dec. 22, 2014, the entireties of which are incorporated herein by this reference.
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| Number | Date | Country | |
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| 20190078388 A1 | Mar 2019 | US |
| Number | Date | Country | |
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| Number | Date | Country | |
|---|---|---|---|
| Parent | 14956897 | Dec 2015 | US |
| Child | 16187067 | US |
