Patent Publication Number: US-2020291725-A1

Title: Floating Plug Anti-Leak

Description:
BACKGROUND 
     Lubricant is used in drill bits for various purposes, among which is to exclude well fluids and debris from interfaces between components of the drill bits that move relative to one another. For example, lubricant may be used between cones of a roller cone bit and journals on which the cones rotate. 
     Currently, lubricant in a roller cone bit is maintained at a pressure which is substantially equal to the surrounding borehole environment, so that seals which isolate the lubricant from well fluids in the environment do not have to withstand significant pressure differentials in use. However, current roller cone bits may allow for a floating plug to slip from a pressure equalization bore that houses the floating plug into a lubricant passage that houses the lubricant used between the cones of the roller cone bit and the journals on which the cones rotate. This may allow for free flow of annulus fluid and/or mud pumped from the surface through the drill bit to reach bearings in the drill bit, which may reduce bearing life. Additionally, the floating plug may slip into other passages, preventing the flow of grease to the bearing, which may also reduce bearing life. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These drawings illustrate certain aspects of some examples of the present disclosure and should not be used to limit or define the disclosure. 
         FIG. 1  is a representative side elevation, partial cross-sectional view of an operational environment for a drilling system, in accordance with one or more embodiments of the disclosure; 
         FIG. 2  is a representative side view of a drill bit which can embody principles of this disclosure in accordance with one or more embodiments of the disclosure; 
         FIG. 3  is a representative cross-sectional view of a body of the drill bit in accordance with one or more embodiments of the disclosure; 
         FIG. 4  is a representative oblique cross-sectional view of an arm of another example of the drill bit; 
         FIGS. 5-9  are representative cross-sectional views of additional examples of the drill bit; 
         FIG. 10  is a representative cross-sectional view of a pressure relief valve which may be used in the drill bit, and which can embody principles of this disclosure, in accordance with one or more embodiments of the disclosure; 
         FIG. 11  is another example of a representative cross-sectional view of the body of the drill bit with a stop; 
         FIGS. 12A-F  are representative cross-sectional views of different stops which may be used in the drill bit in accordance with one or more embodiments of the present disclosure; 
         FIG. 13  is representative cross-sectional view of a ledge which may be used in the drill bit in accordance with one or more embodiments of the present disclosure; and 
         FIG. 14A-C  are representative cross-sectional views of a floating plug which may be used in the drill bit. 
     
    
    
     DETAILED DESCRIPTION 
     This disclosure relates generally to equipment utilized in drilling operations of subterranean wells and, in an example described below, more particularly provides floating plug pressure equalization in drill bits (e.g., roller cone bits). Embodiments of this disclosure may generally relate to a system and method for preventing movement of a floating plug out of a pressure equalization bore in a drill bit. As disclosed below, devices may be employed to prevent the floating plug from ejecting out of the pressure equalization bore and into a fluidly connected lubricant passageway, which may prevent drilling fluid from a wellbore from leaking into a lubricant reservoir that houses a lubricant configured to lubricate portions of the drill bit (e.g., bearings). The lubricant reservoir extends from the floating plug to the bearings. That is, the lubricant reservoir includes the portion of the pressure equalization bore disposed between the floating plug and the lubricant passageway (e.g., a lubricant chamber portion of the pressure equalization bore), as well as the fluidly connected lubricant passageway. Preventing ejection of the floating plug into the lubricant reservoir may allow for longer bearing life by preventing leaks of annulus fluid or mud pumped from the surface from reaching the bearings through the lubricant chamber portion. 
       FIG. 1  illustrates a side elevation, partial cross-sectional view of an operational environment for a drilling system in accordance with one or more embodiments of the disclosure. It should be noted that while  FIG. 1  generally depicts a land-based drilling assembly, those skilled in the art will readily recognize that the principles described herein are equally applicable to subsea drilling operations that employ floating or sea-based platforms and rigs, without departing from the scope of the disclosure. As illustrated, drilling assembly  100  may include a drilling platform  102  that supports a derrick  104  having a traveling stop  106  for raising and lowering a drill string  108 . Drill string  108  may include, but is not limited to, drill pipe and coiled tubing, as generally known to those skilled in the art. A kelly  110  may lowered through a rotary table  112  and can be used to transmit rotary motion from the rotary table to drill string  108 . A drill bit  114  may be attached to the distal end of drill string  108  and may be driven by a downhole motor and/or via rotation of drill string  108 . As drill bit  114  rotates, it penetrates various subterranean formations  116  to form a wellbore  118 . 
       FIG. 2  illustrates an example of drill bit  114  of  FIG. 1 . As illustrated, drill bit  114  is a roller cone bit having one or more conical-shaped roller cones  200  rotatably secured to one or more corresponding arms  202  extending from a main body  204  of drill bit  114 . As illustrated, drill bit  114  (e.g., tri-cone bit) includes three roller cones  200  rotatably secured to three corresponding arms  202 . However, the principles of this disclosure may be incorporated into drill bits  114  having any number of conical-shaped roller cones  200 . Roller cones  200  may have cutting elements  206  (e.g., teeth or inserts) positioned around an exterior surface  208  (e.g., work surface) of each of roller cones  200 . Each of cutting elements  206  may be configured to intermittently engage the various subterranean formations  116  based on an orientation of its corresponding roller or cone  200  with respect to subterranean formation  116  at the bottom of wellbore  118 . As drill string  108  rotates, contact between the drill bit  114  and subterranean formation  116  at the bottom of wellbore  118  may cause roller cones  200  to rotate about their respective axes  210 . Rotation of roller cones  200  may cause each of cutting elements  206  to rotate into contact with subterranean formation  116  at the bottom of wellbore  118  and apply a compressive force to crush at least a portion of subterranean formation  116 . Further, rotation of drill bit  114  may cause cutting element  206  to rotate around a central axis of the drill bit, which may cause cutting element  206  to exert a lateral force while cutting element  206  is in contact with subterranean formation  116  to further crush subterranean formation  116 . In examples, a combination of the rotation from roller cones  200  and the rotation from drill bit  114  may cause cutting elements  206  to penetrate the various subterranean formations  116  to form wellbore  118 . 
       FIG. 3  illustrates a cross-sectional view of one of the conical-shaped roller cones  200  rotatably secured to one of the arms  202  of  FIG. 2  in accordance with one or more embodiments. Drill bit  114 , as characteristic of a roller cone bit, includes a bearing system  300  to rotatably secure the conical-shaped roller cones  200  to the respective arms  202 . Bearing system  300  may include a journal-bearing system, a roller-bearing system, a ball-bearing system, or some combination thereof. As illustrated, drill bit  114  includes a journal bearing system  302  to rotatably secure a cone  304  to a corresponding arm  306 . Arm  306  may include a journal  308  extending from a distal end  310  of the arm. An outer diameter  312  of journal  308  varies along a central axis  314  of journal  308 . For example, a distal end  316  of journal  308  has a smaller outer diameter  312  than other portions of journal  308  to form a thrust flange  318  for supporting axial loads transmitted from cone  304 . Further, journal  308  includes a circumferential journal slot  320  formed in an outer surface  322  of journal  308 . Circumferential journal slot  320  is configured to at least partially house one or more retaining balls  324 . Additionally, cone  304  includes a corresponding circumferential cone slot  326  in an inner surface  348  of cone  304  that is configured to at least partially house the one or more retaining balls  324 . As illustrated, retaining balls  324  are positioned between cone  304  and journal  308  to secure cone  304  on journal  308  of arm  306 . That is, to restrain axial movement of cone  304  with respect to journal  308 . 
     As illustrated in  FIG. 3 , a ball retaining plug  328  is configured to hold the one or more retaining balls  324  in place during drilling operations. Ball retaining plug  328  are positioned within a lubricant passage  330  extending from an external surface  332  of arm  306  to circumferential journal slot  320  formed in outer surface  322  of journal  308 . Ball retaining plug  328  may be secured within lubricant passage  330  via welding or any other suitable process. A proximal end  334  of ball retaining plug  328  is configured to interface with the one or more retaining balls  324 . A distal end  336  of ball retaining plug  328  includes a plug portion  338 . Plug portion  338  is configured to form a seal between ball retaining plug  328  and lubricant passage  330 . In the illustrated embodiment, an outer diameter  340  of a central portion  342  of ball retaining plug  328  is less than a diameter  344  of lubricant passage  330  such that a lubricant may flow through lubricant passage  330  around at least the central portion  342  of the ball retaining plug  328 . 
     Drill bit  114  includes a lubrication system  346  configured to provide a lubricant (e.g., oil, grease) to bearing system  300  to facilitate low-friction rotation of cone  304  with respect to journal  308 . Lubrication system  346  is configured to supply the lubricant to an annular gap  354  formed between the inner surface of cone  304  and the outer surface of journal  308 . Lubrication system  346  includes a lubricant reservoir  350 , which may include any portion of drill bit  114  sealed from wellbore  118  and configured to house the lubricant. Lubricant reservoir  350  may include lubricant chamber portion  352  of pressure equalization bore  358 , lubricant passage  330 , and annular gap  354 . In the illustrated embodiment, the lubricant is supplied to annular gap  354  from lubricant chamber portion  352  via lubricant passage  330 . Moreover, lubrication system  346  includes a floating plug  356  positioned at least partially within a pressure equalization bore  358 . Lubricant chamber portion  352  includes a portion of pressure equalization bore  358  disposed between floating plug  356  and the fluidly connected lubricant passage  330 . Floating plug  356  is configured to travel axially along pressure equalization bore  358  to ensure that the lubricant is at substantially the same pressure as the downhole environment on an exterior  360  of drill bit  114  (e.g., wellbore  118 ) during drilling operations. Floating plug  356  seals lubricant chamber portion  352  from an open portion  362  of pressure equalization bore  358  (e.g., a portion of pressure equalization bore  358  exposed to the downhole environment) such that lubricant chamber portion  352  and open portion  362  of pressure equalization bore  358  are isolated from fluid communication with each other. 
     Drill bit  114  may be manufactured to include pressure equalization bore  358 , lubricant passage  330 , or some combination thereof. Drill bit  114  may be cast, machined, welded, or otherwise manufactured to include pressure equalization bore  358 , lubricant passage  330 , or some combination thereof. In some embodiments, pressure equalization bore  358 , lubricant passage  330 , or some combination thereof, are bored into drill bit  114 . Pressure equalization bore  358 , lubricant passage  330 , or some combination thereof, may be bored into drill bit  114  during manufacturing, at drilling platform  102 , or at any suitable stage. 
     As illustrated, lubrication system  346  further includes seals  364   a,b  configured to prevent debris and well fluids from entering annular gap  354  formed radially between cone  304  and journal  308 . Seals  364   a,b  may also prevent escape of the lubricant via annular gap  354 . Seals  364   a,b  are received in glands or grooves  366  formed in cone  304 . Alternatively, seals  364   a,b  may be received in glands or grooves  366  formed in journal  308 . Although two seals  364   a,b  are depicted in the drawings, any number of seals (including one) may be used in keeping with the scope of this disclosure. Moreover, as cone  304  rotates about journal  308 , seals  364   a,b  preferably rotate with cone  304  against the outer surface of journal  308 . In an alternative example, seals  364   a,b  may remain stationary on journal  308  (e.g., seals  364   a,b  being positioned in the grooves formed in journal  308 ), with cone  304  rotating relative to journal  308  and seals  364   a,b.    
     With continued reference to  FIG. 3 , floating plug  356  is spherically shaped and may include a full sphere. Floating plug  356  may seal lubricant chamber portion  352  from open portion  362  of pressure equalization bore  358 . To form the seal, a circumferential portion  368  of floating plug  356  presses against an inner surface  370  of pressure equalization bore  358 . The circumferential portion  368  of floating plug  356  may deform or flatten based at least in part on contact with inner surface  370  of pressure equalization bore  358 . For example, floating plug  356  could be made entirely or at least exteriorly of an elastomer or other resilient material, which deforms at least partially when floating plug  356  contacts pressure equalization bore  358  to form the seal. During operations, the spherically shaped floating plug  356  rotates within pressure equalization bore  358  without binding and while maintaining the seal against pressure equalization bore  358 . In an alternative example, floating plug  356  may be cylindrically shaped, barrel-shaped, etc. Floating plug  356  may be any shape in keeping with the scope of this disclosure. Further, pressure equalization bore  358  may have other shapes. For example, pressure equalization bore  358  may have a square, triangular, or any other suitable cross-sectional shape. Floating plug  356  may have a shape suitable for use with the cross-sectional shape of pressure equalization bore  358 . 
     In the illustrated embodiment, lubrication system  346  includes a retainer  372  to prevent floating plug  356  from being discharged out of pressure equalization bore  358 . A pressure differential between lubricant chamber portion  352  and open portion  362  of pressure equalization bore  358  may cause floating plug  356  to traverse along the length of pressure equalization bore  358  in any direction. For example, the pressure differential may cause floating plug  356  to move towards open portion  362  of pressure equalization bore  358 . Open portion  362  of pressure equalization bore  358  includes an opening  374  through an external surface  332  of arm  306  of drill bit  114  to exterior  360  (e.g., an annulus formed in wellbore  118  between drill bit  114  and a wellbore wall  376 ). Retainer  372  is configured to restrain movement of floating plug  356  proximate opening  374  such that floating plug  356  is not discharged from pressure equalization bore  358  into wellbore  118 . Further, retainer  372  include a filter  373  that filters well fluid that enters open portion  362  of pressure equalization bore  358 . In an alternative embodiment, open portion  362  of pressure equalization bore  358  may be in fluid communication with an interior  378  of drill bit  114  (e.g., via a passage from retainer  372  to the interior  378 ). During drilling operations, interior  378  may generally be filled with drilling fluid pumped from a rig mud pump (not illustrated). Retainer  372  may be configured to restrain movement of floating plug  356  proximate the opening  374  such that floating plug  356  is not discharged from pressure equalization bore  358  into interior  378  of drill bit  114 . Thus, lubricant chamber portion  352  may be equalized in regard to pressure with either wellbore  118  or interior  378  of drill bit  114 . With continued reference to  FIG. 3 , friction between floating plug  356  and inner surface  370  of pressure equalization bore  358  may cause some variation in the pressure differential between open portion  362  of pressure equalization bore  358  and lubricant chamber portion  352 . However, floating plug  356  may move along pressure equalization bore  358  to relieve pressure differentials across floating plug  356  such that lubricant chamber portion  352  may be at least partially equalized with open portion  362  of pressure equalization bore  358 , which may be equal to the pressure of either wellbore  118  or interior  378  of drill bit  114 . 
     With pressure at least partially equalized between open portion  362  of pressure equalization bore  358  and lubricant chamber portion  352 , pressure across seals  364   a,b  may be substantially zero, since seals  364  are exposed to the lubricant on one side and wellbore  118 , which shares a pressure with open portion  362  of pressure equalization bore  358 , on an opposite side of seals  364 . However, a pressure in annular gap  354  between the at least two seals  364   a,b  may not be equalized with lubricant chamber portion  352 , wellbore  118 , or interior  378  of drill bit  114 . Thus, a pressure differential may still exist across each seal  364   a,b  in the example depicted in  FIG. 3 . In other examples described below, pressure across each of seals may be substantially equalized, using the principles of this disclosure. 
     In  FIG. 4 , another embodiment of arm  306  is representatively illustrated in an oblique cross-sectional view, with cone  304 , ball retainer plug  328 , and retaining balls  324  removed for clarity. Retainer  372  is positioned within open portion  362  of pressure equalization bore  358 . As illustrated, retainer  372  does not include filter  373 , but filter  373  may be provided. For example, filter  373  may be positioned within an axial bore  400  of retainer  372 . Filter  373  may be configured to filter fluids entering open portion  362  of pressure equalization bore  358  through retainer  372  to prevent debris from entering pressure equalization bore  358 . Such debris may hinder movement of floating plug  356  along pressure equalization bore  358 , which may cause the pressure differential between lubricant reservoir  350  and wellbore  118  to increase. 
     Moreover, in the illustrated embodiment, lubrication system  346  includes another passage (e.g., a secondary passage  402 ) extending from lubricant passage  330  toward distal end  316  of journal  308 . Secondary passage  402  may supply lubricant to annular gap  354  between journal  308  and cone  304 . Thus, as illustrated in  FIG. 4 , the lubricant may flow from lubricant chamber portion  352  to annular gap  354  via lubricant passage  330  and secondary passage  402 . 
     As illustrated in  FIG. 5 , another embodiment of arm  306  is representatively illustrated. Pressure across seal  364   b  is equalized using a floating plug  356 , similar to the manner in which floating plug  356  is used in  FIGS. 2 &amp; 3 . Note that a conventional pressure equalization device (such as, a diaphragm or membrane, etc.) is preferably used with the configuration of  FIG. 5  for equalization of pressure between lubricant chamber portion  352  and exterior  360  of drill bit  114 . 
     In  FIG. 5 , floating plug  356  may provide for equalization of pressure across at least seal  364   b,  thereby also substantially equalizing pressure across each seal  364   a,b,  while also preventing leakage through annular gap  354 , even if at least one seal  364   a,b  may fail. For example, even if seal  364   a  may fail, seal  364   b  and floating plug  356  may prevent well fluid from flowing into lubricant chamber portion  352  via annular gap  354  or open portion  362  of pressure equalization bore  358 , respectively. 
     As pressure across seal  364   b  is equalized, one side of seal  364   b  is exposed to the pressure in lubricant chamber portion  352  (e.g., via lubricant passage  330  or secondary passage  402 ) and an opposite side of seal  364   b  is exposed to annular gap  354 . During operations, pressure in lubricant chamber portion  352  is equalized with pressure on exterior  360  of drill bit  114  (e.g., using a conventional pressure equalization device, or using floating plug  356  and pressure equalization bore  358  of  FIGS. 2 &amp; 3 , etc.) as one side of seal  364   a  is exposed to annular gap  354  and an opposite side of seal  364   a  is exposed to the pressure on exterior  360  of drill bit  114 . Thus, pressure on both sides of each seal  364   a,b  may be equalized with pressure on exterior  360  of drill bit  114  and neither seal  364   a,b  has a substantial pressure differential across it. 
       FIG. 6  illustrates another configuration of drill bit  114  in accordance with one or more embodiments. As illustrated, lubricant chamber portion  352  and open portion  362  of pressure equalization bore  358  are extended, thereby providing further available displacement of the floating plug  356 . This, in turn, provides more initial volume for lubricant, more volume for thermal expansion of the lubricant, and/or more volume for compression of the lubricant at downhole pressures. 
       FIG. 7  illustrates another example of drill bit  114  in which floating plug  356  is positioned between lubricant chamber portion  352  and open portion  362  of pressure equalization bore  358  to equalize pressure across seal  364   a.  For example, lubricant chamber portion  352  is in fluid communication with annular gap  354  between seals  364   a,b,  and open portion  362  of pressure equalization bore  358  is in fluid communication with exterior  360  of drill bit  114 . 
     Lubricant chamber portion  352  is also pressure equalized with exterior  360  of drill bit  114  (e.g., as in the examples of  FIGS. 2 and 3  or using a conventional pressure equalization device), the result may be that pressure across each seal  364   a,b  is substantially equalized, as illustrated in  FIG. 6 . Note that, in other examples, pressures exposed to seals  364   a,b  may be equalized with pressure in interior of drill bit  114  (for example, by providing fluid communication between open portion  362  of pressure equalization bore  358  and the interior of drill bit  114 ). 
     Referring to  FIG. 8 , another example of drill bit  114  is illustrated. This example is similar in many respects to  FIG. 6 , but differs at least in that lubrication system  346  includes both floating plug  356  and an additional floating plug (e.g., a second floating plug  800 ). Second floating plug  800  may be positioned within pressure equalization bore  358 pressure equalization bore  358  to equalize pressure between exterior  360  and annular gap  354  between seals  364   a,b.    
     Referring to  FIG. 9 , another example of drill bit  114  is representatively illustrated, in which pressure equalization bore  358  extends through arm  306 , and floating plug  356  is sealed and reciprocally received in pressure equalization bore  358 . Open portion  362  of pressure equalization bore  358  is in fluid communication with exterior  360  of drill bit  114 , and lubricant chamber portion  352  is in fluid communication with annular gap  354  between seals  364   a,b.  An enlarged bypass chamber  900  is provided at an end of lubricant chamber portion  352  of pressure equalization bore  358 , in order to allow well fluid to bypass floating plug  356 , for example, in the event that there is excessive loss of lubricant from lubricant chamber portion  352 . As lubricant is lost from lubricant chamber portion  352 , floating plug  356  displaces toward the bypass chamber  900  (e.g., open portion  362  of pressure equalization bore  358  lengthens, and lubricant chamber portion  352  shortens). Eventually, floating plug  356  may enter the bypass chamber  900 , and the well fluid may then flow around floating plug  356 . In this manner, pressure across seals  364   a,b  may still be equalized, even though floating plug  356  may no longer isolate the lubricant from the well fluid. 
       FIG. 10  illustrates drill bit  114  in which floating plug  356  may be used as part of a pressure relief valve  1000  in addition to being used to substantially equalize pressure between lubricant chamber portion  352  and exterior  360  of drill bit  114  in accordance with one or more embodiments. Pressure relief valve  1000  includes floating plug  356 , a biasing device  1002  (e.g., a spring), and an enlarged dimension or recess  1004  in the bore, which allows fluid to bypass floating plug  356 . As illustrated, the pressure relief valve is positioned within open portion  362  of pressure equalization bore  358 . 
     Further, open portion  362  of pressure equalization bore  358  mis in fluid communication with exterior  360  of drill bit  114 , and lubricant chamber portion  352  is in fluid communication with other portions of the lubricant reservoir  350 . If (for example, due to thermal expansion, etc.) there is excess pressure in lubricant chamber portion  352 , the pressure differential across floating plug  356  may displace the plug in a direction toward the biasing device  1002 . For example, the pressure differential may displace floating plug  356  such that floating plug  356  contacts the biasing device  1002 . The biasing device  1002  may exert a biasing force to counteract the displacement of the floating plug  356 . Based on the pressure differential, floating plug  356  may continue to travel along pressure equalization bore  358  against the biasing device  1002  until floating plug  356  has displaced sufficiently (or, until a predetermined pressure differential across floating plug  356  has been exceeded) for lubricant to flow via the enlarged dimension or recess  1004  to exterior  360 , thereby relieving the excess pressure in lubricant chamber portion  352 . In another example, pressure relief valve  1000  may be incorporated into the configuration of  FIG. 9  for equalizing the pressure across seal  364   a.  Biasing device  1002  and recess  1004  could, for example, be provided in pressure equalization bore  358  of the  FIG. 8  configuration, or of any of the other configurations described above. 
       FIG. 11  illustrates a stop  1100  positioned within lubricant chamber portion  352  of  FIG. 4  in accordance with one or more embodiments. Stop  1100  may also be referred to as a block. During drilling operations, the lubricant (e.g., grease) may be consumed at seals  364   a,b  or otherwise ejected. Traditionally, lubricant reservoir  350  may leak (e.g., fail to seal the lubricant from the well fluid) when a certain amount of the lubricant is consumed. For example, as the lubricant is consumed, the pressure differential may cause floating plug  356  to slide and/or move along pressure equalization bore  358  toward a first end  1102  of lubricant chamber portion  352  proximate lubricant passage  330 . It may be possible for floating plug  356  to pass through first end  1102  of lubricant chamber portion  352  and move into lubricant passage  330 . As set forth above, floating plug  356  is configured to form a seal against pressure equalization bore  358 . Thus, floating plug  356  ejecting into lubricant passage  330  removes the seal isolating the lubricant from the well fluid, which causes lubricant reservoir  350  to leak. However, as illustrated, lubrication system  346  includes stop  1100  configured to restrict the movement of floating plug  356  to keep floating plug  356  from ejecting into lubricant passage  330  (e.g., a retaining ball plug hole), a bleed hole, or the like. Therefore, stop  1100  causes floating plug  356  to maintain the seal even when the lubricant (e.g., grease) is depleted or the certain amount of the lubricant is consumed. This may translate to longer bearing life. 
     Referring now to  FIGS. 12A-F , floating plug  356  may interact with stop  1100  in accordance with one or more embodiments. It should be noted that there may be any number of various different types of floating plugs  356 , which may be used in conjunction with stop  1100 . In one example, floating plug  356  is made entirely of an elastomer sealing material for seal engaging against pressure equalization bore  358  to isolate lubricant chamber portion  352 , and other portions of lubricant reservoir  350  (e.g., lubricant passage  330 ), from open portion  362  of pressure equalization bore  358 . However, floating plug  356  may be made of any suitable material.  FIGS. 12A-F  illustrate various examples of stop  1100 . These are merely a few examples of a wide variety of different stops  1100  which may be used, and so it should be clearly understood that the scope of this disclosure is not limited at all to only the specific shapes and types of stops  1100  described herein and depicted and described within this disclosure. 
       FIG. 12A  illustrates stop  1100  as a solid body in accordance with one or more embodiments. Stop  1100  may have a substantially cylindrical shape or any other suitable shape. In the illustrated embodiment, stop  1100  has a cylindrical shape. Stop  1100  is press-fit, slip-fit, or machined within pressure equalization bore  358  to hold stop  1100  in place such that stop  1100  may restrict the movement of floating plug  356  to keep floating plug  356  from ejecting into lubricant passage  330 . However, lubricant positioned between floating plug  356  and stop  1100  is configured to flow to annular gap  354  via lubricant passage  330 , and the press-fit may prevent flow past stop  1100  along pressure equalization bore  358 . Thus, as illustrated, drill bit  114  includes a bypass line  1200  that is connected to pressure equalization bore  358  at one end and lubricant passage  330  at an opposing end. Bypass line  1200  is configured to direct the lubricant positioned between floating plug  356  and stop  1100  to lubricant passage  330 . 
     Alternatively, stop  1100  may not be press-fit in pressure equalization bore  358 . Stop  1100  may have a shape configured to permit fluid to flow past stop  1100  along pressure equalization bore  358 . An outer diameter  1202  of stop  1100  may be less than a diameter  1204  of pressure equalization bore  358 . The lubricant may be configured to flow past stop  1100  through an annulus  1206  formed between stop  1100  and pressure equalization bore  358 . However, as stop  1100  is not press fit in pressure equalization bore  358 , stop  1100  may slide along pressure equalization bore  358 . To restrain stop  1100  (e.g., solid body) from sliding along pressure equalization bore  358 , pressure equalization bore  358  may include a ledge or reduced diameter, which may prevent stop  1100  from sliding into lubricant passage  330 . In another example, stop  1100  may extend from pressure equalization bore  358  into lubricant passage  330  and to an opposite side wall  1208  of lubricant passage  330  such that contact with opposite side wall  1208  restrains axial movement (e.g., sliding) of stop  1100  in a direction toward lubricant passage  330 . Further, in another example, stop  1100  may extend into lubricant passage  330  to a portion of the ball restraining plug such that contact with the ball restraining plug restrains axial movement of stop  1100  in a direction toward lubricant passage  330 . Restraining the axial movement of stop  1100  toward lubricant passage  330  may maintain stop  1100  at least partially positioned within pressure equalization bore  358 , such that stop  1100  may keep floating plug  356  from ejecting into lubricant passage  330 . 
       FIG. 12B  illustrates stop  1100  with a solid body and a cup  1210  for receiving floating plug  356  in accordance with one or more embodiments. Stop  1100  may be press-fit in bore pressure equalization bore  358 , and bypass line  1200  (e.g., referring to  FIG. 12A ) directs the lubricant positioned between floating plug  356  and stop  1100  to lubricant passage  330 . Additionally, stop  1100  may have a shape configured to permit fluid (e.g., the lubricant) to flow past stop  1100  along pressure equalization bore  358 . That is, the lubricant may flow through the annulus  1206  formed between stop  1100  and pressure equalization bore  358 . Moreover, cup  1210  is configured to receive the floating plug  356 . Cup  1210  may be any suitable geometry for receiving the floating plug  356 . Without limitation, the suitable geometry may be chamfered, rounded, flat, convex, concave, or the like. Additionally, although  FIG. 12B  illustrates cup  1210  positioned on one side of stop  1100 , it should be noted that on the opposite side of stop  1100  may include cup  1210 , or any suitable geometry such as chamfered, flat, rounded, convex, concave, and/or the like. To that end, the body of stop  1100  may be any suitable shape such as a cylinder, a sphere, and/or the like. 
       FIG. 12C  further illustrates stop  1100  with a slotted body including slots or grooves  1212  in accordance with one or more embodiments. Slots or grooves  1212  may be evenly spaced, not evenly spaced, strait, helix or any other geometry. It should be noted that the slots or grooves  1212  may not be formed in an exterior surface  1214  of stop  1100  but may traverse through stop  1100  along an axial length  1216  of stop  1100 . Additionally, the slots or grooves  1212  may be positioned on an inner surface  370  of pressure equalization bore  358 . Lubricant positioned between floating plug  356  and stop  1100  may be configured to flow through the slots  1212  in its path to annular gap  354 . Moreover, stop  1100  with the slotted body may be press-fit, or otherwise secured, within pressure equalization bore  358 . 
       FIG. 12D  illustrates stop  1100  having an annular body in accordance with one or more embodiments. The annular body of stop  1100  includes a stop bore  1218  extending through the axial length  1216  of stop  1100 . It should be noted stop bore  1218  may not be centered within the annular body of stop  1100  and there may be any number of stop bores  1218 . The lubricant positioned between floating plug  356  and stop  1100  may be configured to flow through stop bore  1218  in its path to annular gap  354 . Moreover, stop  1100  may be press-fit, or otherwise secured, within pressure equalization bore  358 . Alternatively, stop  1100  is not press-fit in pressure equalization bore  358 . Instead, stop  1100  and/or pressure equalization bore  358  may be machined undersized, and/or formed, in place. Further, as set forth above, a portion of stop  1100  may extend into lubricant passage  330  such that a portion of lubricant passage  330  or the ball restraining plug may restrain axial movement of stop  1100  in a direction toward lubricant passage  330 . 
       FIG. 12E  illustrates stop  1100  having the annular body in accordance with one or more embodiments. The annular body of stop  1100  includes stop bore  1218  through the axial length  1216  of stop  1100 . Further, stop  1100  includes a pass-through bore  1220  of any geometry. It should be noted that pass-through bore  1220  may not be centered within the annular body of stop  1100  and there may be any number of pass-through bores  1220 . The lubricant positioned between floating plug  356  and stop  1100  may be configured to flow through the stop bore  1218  and/or the pass-through bore  1220  in its path to annular gap  354 . Moreover, stop  1100  may be press-fit, or otherwise secured, within pressure equalization bore  358 . 
       FIG. 12F  illustrates a stop  1222  in lubricant passage  330  configured to prevent stop  1100  from traversing into lubricant passage  330  in accordance with one or more embodiments. As set forth above in  FIGS. 12A-12F , each stop  1100  may include press fit, slip fit, or tight fit tolerances, except for a solid body illustrated in  FIG. 11A . Further, during operations, stop  1100  functions to prevent floating plug  356  from moving into lubricant passage  330  from lubricant chamber portion  352 . Moreover, as discussed below, stop  1100  may work in conjunction with stop  1222  to prevent the movement of floating plug  356  into lubricant passage  330  from lubricant chamber portion  352 . For any items above not machined or press fit into lubricant chamber portion  352 , the design may accommodate the perpendicular hole (e.g., lubricant passage  330 ) volume, or pressure equalization bore  358 . For example, the length of stop  1100  part may be longer than the diameter of lubricant passage  330  of the inclusion of stop  1222 . In another example, the ball retaining plug may allow for a shorter stop  1222  to be used, as the ball retaining plug blocks at least a portion of the passage&#39;s  330  cross-section. 
     Without limitations, stop  1100  and stop  1222  may be keyed for orientation. For example, if a special feature and/or geometry is used on stop  1222  that needs to be oriented toward lubrication chamber  352 , then stop  1222  may be keyed to elicit a specified orientation. To that end, stop  1222  may have a feature such as cup  1210  on any surface of stop  1222  to receive floating plug  356 . This feature does not have to be cup  1210 . It may instead be a flat feature or any other feature, as described above. It should be noted that, as illustrated in  FIGS. 12A-12F , stop  1222  may have any of the same features, properties, and/or characteristics of stop  1100 . Similar to stop  1100 , stop  1222  may also include press fit or tight fit tolerances, unless stop  1222  includes a solid body. 
       FIG. 13  illustrates the lubrication chamber  352  of pressure equalization bore  358  having a ledge  1300  configured to keep floating plug  356  from ejecting into lubricant passage  330  in accordance with one or more embodiments. Ledge  1300  is configured to restrict movement of floating plug  356 , such that stop  1100  may not be needed to keep floating plug  356  from ejecting into lubricant passage  330 . Ledge  1300  may be machined into pressure equalization bore  358 . In the illustrated embodiment, ledge  1300  includes an annular platform  1302 . Ledge  1300  may be formed via a decrease in diameter of pressure equalization bore  358  in a portion of pressure equalization bore  358  proximate lubricant passage  330 .Ledge  1300  may not be continuous all the way around lubricant passage  330 . Instead, ledge  1300  may extend across at least a portion of pressure equalization bore  358  in a single location (e.g., as a cantilever beam) or a combination of locations (e.g., a 2-legged or 3-legged bridge). Moreover, as illustrated, ledge  1300  is positioned within pressure equalization bore  358 . Alternatively, ledge  1300  may be positioned at least partially within lubricant passage  330 . 
       FIG. 14A  illustrates floating plug  356  having a cylindrical shape (e.g., a cylindrical floating plug  356 ) in accordance with one or more embodiments. As set forth above, the differential pressure between lubricant chamber portion  352  and open portion  362  of pressure equalization bore  358  may cause cylindrical floating plug  356  to move toward lubricant passage  330 . Without stop  1100 , it is possible for cylindrical floating plug  356  to eject into lubricant passage  330 , thereby breaking the seal that is configured to isolate the lubricant from the well fluid. However, as illustrated, cylindrical floating plug  356  has an axial length  1400  greater than diameter  344  of lubricant passage  330  such that a portion of cylindrical floating plug  356  remains in pressure equalization bore  358  when cylindrical floating plug  356  is fully extended into lubricant passage  330 . That is, when cylindrical floating plug  356  extends into lubricant passage  330  and to opposite side wall  1208  of lubricant passage  330 . Contact between opposite side wall  1208  of lubricant passage  330  and an axial end  1402  of cylindrical floating plug  356  restrains cylindrical floating plug  356  from sliding further into lubricant passage  330 . A sealing portion  1404  of cylindrical floating plug  356  (e.g., a portion of the plug remaining in pressure equalization bore  358 ) is configured to maintain the seal that is configured to isolate the lubricant from the well fluid. 
       FIG. 14B  illustrates floating plug  356  with a cylindrical shape and extending into lubricant passage  330  having ball retaining plug  328  positioned therein in accordance with one or more embodiments. Ball retaining plug  328  is configured to restrain the floating plug  356  from sliding further into lubricant passage  330  and/or ejecting into lubricant passage  330 . That is, contact between ball retaining plug  328  and axial end  1402  of floating plug  356  restrains floating plug  356  from sliding further into lubricant passage  330 . 
       FIG. 14C  illustrates floating plug  356  having a spherical shape and extending into lubricant passage  330  in accordance with one or more embodiments. As illustrated, diameter  1204  of pressure equalization bore  358  is greater than diameter  344  of lubricant passage  330 . Further, floating plug  356  has a radius  1420  greater than diameter  344  of lubricant passage  330  such that a portion of floating plug  356  remains in pressure equalization bore  358  when floating plug  356  is fully extended into lubricant passage  330 . That is, when floating plug  356  extends into lubricant passage  330  and to opposite side wall  1208  of lubricant passage  330 . Contact between opposite side wall  1208  of lubricant passage  330  and circumferential portion  368  of floating plug  356  may restrain floating plug  356  from sliding further into lubricant passage  330 . Moreover, the portion of floating plug  356  remaining in pressure equalization bore  358  when floating plug  356  is fully extended into lubricant passage  330  is configured to maintain the seal that is configured to isolate the lubricant from the well fluid. 
     In accordance with present embodiments, all floating plugs  356  and stops  1100  in  FIGS. 12A-14C  may be used in any combination. For example, cup  1210  may be included with stop  1100  having the annular body. Moreover, any version or combinations of floating plug  356  or stop  1100  may be symmetric or a-symmetric. For example, stop  1100  may have a first slot  1212  extending along a first side of stop  1100  and a second slot  1212  extending along an opposing second side of stop  1100 . In another example, stop  1100  may have a single slot  1212  extending along the first side of stop  1100 . Moreover, the material used for floating plug  356  or stop  1100  may be of any material that may maintain structural integrity in the applied environment considering such things as temperature, corrosion, fluid compatibility, etc. For example, a steel or plastic may be used so long as it will not fail at temperature and is compatible with the lubricant (e.g., grease). 
     In accordance with present embodiments, all features of the stops  1222  in  FIG. 12F  may be used in any combination with the features described for floating plug  356  or stop  1100 . For example, cup  1210  may be included with stop  1222 . Further, as set forth above, any version or combinations of stop  1222 , the floating plug  356 , and stop  1100  may be symmetric or a-symmetric. Moreover, the material used for stop  1222  may be of any material that may maintain structural integrity in the applied environment considering conditions such as temperature, corrosion, fluid compatibility, etc. For example, a steel or plastic may be used so long as it will not fail at temperature and is compatible with the grease. 
     The preceding description provides various examples of the systems and methods of use disclosed herein which may contain different method steps and alternative combinations of components. Among other things, improvements over current wellbore drilling operations include preventing the floating plug from slip into other portions of the lubricant reservoir (e.g., the passage), thereby maintaining the seal isolating the lubricant reservoir from the well fluid, which may extend bearing life of the bearing system of the roller cone bit. 
     Statement 1. A roller cone drill bit may comprise a pressure equalization bore defined within the roller cone drill bit that includes a lubricant chamber portion and an open portion; a lubricant passage defined within the drill bit and fluidically coupled to a first end of the lubricant chamber portion; a floating plug positioned within the pressure equalization bore between the lubricant chamber portion and the open portion, wherein the floating plug is slidable along the pressure equalization bore and seals the lubricant chamber portion from the open portion; and a stop positioned at least partially within the pressure equalization bore or the lubricant passage, wherein the stop restrains the floating plug from sliding into the lubricant passage through the first end of the lubricant chamber portion. 
     Statement 2. The drill bit of statement 1, further comprising a bypass line that is connected to the pressure equalization bore at one end and the lubricant passage at an opposing end of the bypass line. 
     Statement 3. The drill bit of statement 1 or statement 2, wherein the stop is a ledge machined into the pressure equalization bore. 
     Statement 4. The drill bit of statement 1 or statement 2, wherein the stop is a solid body. 
     Statement 5. The drill bit of any proceeding statement, wherein the stop further includes a cup configured to receive the floating plug. 
     Statement 6. The drill bit of any proceeding statement, wherein the stop is chamfered, flat, rounded, convex, concave, or any combination thereof. 
     Statement 7. The drill bit of any of statements 1, 2, 5, or 6 wherein the stop further includes an annular body having a stop bore extending axially through the stop. 
     Statement 8. The drill bit of any of statements 1, 2, or 5-7, wherein the stop further includes a pass-through bore. 
     Statement 9. The drill bit of any of statements 1, 2, or 5-8, wherein the stop is press-fit into the lubricant chamber portion. 
     Statement 10. The drill bit of any of statements 1-3, 5, or 6, wherein the stop is machined into the lubricant chamber portion. 
     Statement 11. The drill bit of any proceeding statement, wherein the stop further includes a slotted body. 
     Statement 12. The drill bit of any proceeding statement, wherein at least a part of the lubricant chamber portion has a diameter that is smaller than the floating plug. 
     Statement 13. A method for forming a lubricant reservoir may comprise manufacturing a drill bit with a pressure equalization bore fluidically coupled to a lubricant passage and the lubricant passage fluidically coupled to one or more bearings; positioning a stop at least partially within the lubricant passage or the pressure equalization bore of the drill bit, wherein the lubricant passage is fluidically coupled to a first end of a lubricant chamber portion of the pressure equalization bore; positioning a floating plug within the pressure equalization bore between the lubricant chamber portion and an open portion of the pressure equalization bore, and wherein the floating plug is slidable along the pressure equalization bore and seals the lubricant chamber portion from the open portion; and filling the lubricant reservoir with a lubricant, the lubricant reservoir extending from the floating plug in the lubricant chamber portion of the pressure equalization bore, through the lubricant passage, and to the one or more bearings. 
     Statement 14. The method of statement 13, further comprising boring out the drill bit to form the pressure equalization bore. 
     Statement 15. The method of statement 13, further comprising casting the drill bit to form the pressure equalization bore and the lubricant passage. 
     Statement 16. The method of any of statements 13-15, wherein the pressure equalization bore includes a bypass line that is connected to the pressure equalization bore at one end and to the lubricant passage at an opposing end of the bypass line. 
     Statement 17. The method of any of statements 13-16, wherein the stop includes a slotted body. 
     Statement 18. The method of any of statements 13-17, wherein the stop is a ledge machined into the pressure equalization bore. 
     Statement 19. The method of any of statements 13-17, wherein the stop is a solid body. 
     Statement 20. The method of any of statements 13-19, wherein the stop is chamfered, flat, rounded, convex, concave, or any combination thereof. 
     It should be understood that, although individual examples may be discussed herein, the present disclosure covers all combinations of the disclosed examples, including, without limitation, the different component combinations, method step combinations, and properties of the system. It should be understood that the 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. Moreover, the indefinite articles “a” or “an,” as used in the claims, are defined herein to mean one or more than one of the element that it introduces. 
     For the sake of brevity, only certain ranges are explicitly disclosed herein. However, ranges from any lower limit may be combined with any upper limit to recite a range not explicitly recited, as well as, ranges from any lower limit may be combined with any other lower limit to recite a range not explicitly recited, in the same way, ranges from any upper limit may be combined with any other upper limit to recite a range not explicitly recited. Additionally, whenever a numerical range with a lower limit and an upper limit is disclosed, any number and any included range falling within the range are 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 even if not explicitly recited. Thus, every point or individual value may serve as its own lower or upper limit combined with any other point or individual value or any other lower or upper limit, to recite a range not explicitly recited. 
     Therefore, the present examples are well adapted to attain the ends and advantages mentioned as well as those that are inherent therein. The particular examples disclosed above are illustrative only, and may be modified and practiced in different but equivalent manners apparent to those skilled in the art having the benefit of the teachings herein. Although individual examples are discussed, the disclosure covers all combinations of all of the examples. Furthermore, no limitations are intended to the details of construction or design herein shown, other than as described in the claims below. Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. It is therefore evident that the particular illustrative examples disclosed above may be altered or modified and all such variations are considered within the scope and spirit of those examples. If there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.