Patent Publication Number: US-2018038171-A1

Title: Alignable Connector

Description:
BACKGROUND 
     When exploring for or extracting subterranean resources such as oil, gas, or geothermal energy, it is common to form boreholes in the earth. Such boreholes are often formed by suspending a specialized drill bit from a derrick or offshore platform and rotating the drill bit to engage and degrade the earth as it turns. The drill bit may be suspended by coiled tubing or a series of drill pipe sections connected end-to-end forming a drill string, and rotated at the derrick/platform or by a downhole motor disposed towards an end of the drill string. 
     In many situations, it may be desirable to pass power or commands down a drill string to control tools or other devices disposed along the drill string. Such commands may attempt to alter drilling parameters to increase a rate of penetration of the drill bit or to steer the drill bit towards an attractive destination. It may also be desirable to gather information about an earthen formation being drilled and pass it up a drill string to the surface or along the drill string to other tools or devices. To gather this information, various types of sensors have been placed along drill strings or on drill bits to collect data. 
     Transmitting power, commands or information along a drill string or to and from a drill bit may prove challenging. First, connections between drill pipe sections and drill bits are often made in wet and dirty environments where drilling mud and greases may be prevalent. Contamination of connections by such materials may lead to faulty and unreliable communication. To avoid contamination, some have turned to electrical stab connectors with wipers thereon to make electrical connections in these types of dirty environments. A typical stab connector may comprise an electrically conductive projection axially alignable with an electrically conductive receptacle. The projection may be inserted into and received by the receptacle when axially translated relative thereto such that an electrical connection is made. To hinder drilling mud or grease from contaminating the connection, a wiper may be positioned at a mouth of the receptacle to wipe possible contaminates from the projection as it is inserted. Such a stab connector may not work properly, however, if the projection and receptacle are not continuously aligned. Second, it is common for drill pipe sections and drill bits to be threaded together. Such threaded rotational connections may make keeping a stab connector aligned difficult. 
     BRIEF DESCRIPTION 
     A connection between drill pipe sections or a drill bit may maintain alignment while two elements are threadably attached one to another. Such a connection may comprise a first element comprising a rotor rotatable with respect to a stator. A second element may thread to the stator. As it does so, the second element may rotationally fix itself to the rotor allowing for connecting elements on the second element and the rotor to align. These connecting elements may remain aligned while the second element and rotor rotate with respect to the stator. Such alignment may allow for a connection to be kept clean and free from contamination in otherwise wet and dirty environments. 
    
    
     
       DRAWINGS 
         FIG. 1  is an orthogonal view of an embodiment of a drilling operation comprising a drill bit secured to an end of a drill string suspended from a derrick. 
         FIG. 2  is a longitude-sectional view of an embodiment of drill bit, comprising a rotor rotatable with respect to a stator, positioned proximate an end of a drill string, threadably attachable to the stator and rotationally fixable with the rotor. 
         FIG. 3  is a longitude-sectional view of an embodiment of drill bit comprising a rotor with a pin extending therefrom received within a slot on an end of a drill string. 
         FIG. 4  is a perspective view of an embodiment of a drill bit disconnected from an end of a drill string. 
         FIG. 5  is a longitude-sectional view of an embodiment of drill pipe section, comprising a rotor rotatable with respect to a stator, positioned proximate another drill pipe section, threadably attachable to the stator and rotationally fixable with the rotor. 
         FIG. 6  is a perspective view of an embodiment of a drill bit, comprising a rotor with a plurality of crenellations disposed thereon, disconnected from an end of a drill string, comprising a plurality of mating crenellations disposed thereon. 
         FIGS. 7-1 and 7-2  are longitude-sectional views of an embodiment of a drill bit comprising a rotor with a slot disposed therein capable of receiving a pin extending from an end of a drill string, wherein a spring disposed adjacent the pin may absorb some force experienced by the pin. 
         FIGS. 8-1 and 8-2  are longitude-sectional views of an embodiment of a drill bit comprising a rotor rotationally fixable to an end of a drill string by a mule shoe connection. 
         FIG. 9  is a longitude-sectional view, including a magnified portion, of an embodiment of a drill bit comprising a rotor rotatable with respect to a stator and inductive rings capable of passing electrical signals during rotation. 
         FIG. 10  is a longitude-sectional view of an embodiment of a drill bit comprising a rotor rotatable with respect to a stator capable of passing optical signals during rotation. 
         FIG. 11  is a longitude-sectional view of an embodiment of a drill bit comprising a rotor rotatable with respect to a stator capable of passing fluid during rotation. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows an embodiment of a drilling operation comprising a drill bit  112  suspended from a derrick  113  by a drill string  114 . The drill bit  112  may be rotated from the derrick  113  by a top drive, by a downhole motor disposed within the drill string  114 , or by a combination of the two. As the drill bit  112  rotates it may engage and degrade an earthen formation  116  to form a borehole  111  therein. The drill bit  112  may be fed into the borehole  111  formed in the earthen formation  116  as the borehole  111  lengthens. Any of a variety of known downhole drill bits, such as a roller-cone bit or drag bit, may be used. Tools or other devices may be disposed at various locations along the drill string  114  to perform such tasks as controlling a rate of penetration of the drill bit or steering the drill bit towards an attractive destination. To gather information about the earthen formation  116  being drilled or the process of drilling as it progresses, any of a variety of sensors may be disposed along the drill string  114  or on the drill bit  112 . While the present embodiment shows the drill string  114  suspended from a land based derrick  113 , those of ordinary skill in the art will recognize that other configurations, such as suspending a drill string from an offshore platform are also possible. 
       FIG. 2  shows an embodiment of a drill bit  212  positioned proximate an end of a drill string  220 . The drill bit  212  may comprise an internal component  221  residing within an external component  222 . The external component  222  may comprise a working face  223  positioned opposite an opening  224 . The working face  223  may comprise a plurality of cutters  299  comprising a superhard material (e.g. polycrystalline diamond) disposed on a series of blades  298  extending therefrom. The working face  223  may also comprise a plurality of nozzles  236  disposed thereon allowing for drilling fluid to discharge from the drill bit  212 . 
     The opening  224  may provide for attachment of the drill bit  212  to the drill string  220 . In the embodiment shown, the drill string  220  comprises a protrusion  225  extending from an end thereof with a first threaded surface  226  disposed on the protrusion  225 . A second threaded surface  227  may be disposed on an internal surface within the opening  224  mateable with the first threaded surface  226 . 
     The internal component  221  may be accessible through the opening  224 . In the present embodiment, the internal component  221  is retained within the opening  224  by an insert  282  secured therein that retains the internal component  221  within the external component  222 . An aperture disposed within the insert  282  may provide the internal surface comprising the second threaded surface  227 . 
     The internal component  221  may comprise a pin  228  extending therefrom. The pin  228  may be received within a slot  229  disposed on the protrusion  225  as the first threaded surface  226  and second threaded surface  227  are mated together. In this manner, the protrusion  225  of the drill string  220  may engage with the internal component  221  such that the two rotate together with respect to the external component  222 . While in the embodiment shown, a pin is disposed on an internal component and a slot is disposed on a protrusion, it should be understood that the reverse could be true with similar functionality. Further, other mechanisms could be employed to rotationally fix an internal component to a protrusion as threaded surfaces mate to achieve a similar effect. 
     One advantage of the elongated pin  228  and slot  229  shown in the present embodiment is that they may axially translate relative to each other for a considerable distance while the first and second threaded surfaces  226 ,  227  are threading together. Another advantage of an elongated pin  228  is that it may be longer than a stab connection aligned parallel with a rotational axis of the internal component  221 . The stab connection may comprise an electrically conductive projection  280 , disposed on the protrusion  225  and parallel with the pin  228 , axially alignable with an electrically conductive receptacle  281 , disposed on the internal component  221 . By being longer than the stab connection, the pin  228  may align the projection  280  and receptacle  281  before stabbing. 
       FIG. 3  shows another embodiment of a drill bit  312  with a protrusion  325  completely threaded into an opening  324  thereof. When threaded, a projection  380  of a stab connection may be received by a receptacle  381 . The stab connection may comprise at least one wiper  330  to clean possible contaminates from the stab connection during stabbing. 
     An external component  322  of the drill bit  312  may comprise a sensor  331  disposed thereon capable of measuring any of a variety of parameters of an earthen formation or a drilling operation as it progresses. The sensor  331  may be electrically connected to a first conductive ring  332  disposed on the external component  322 . The first conductive ring  332  may be in physical contact with a second conductive ring  333  disposed on an internal component  321 . As the internal component  321  and external component  322  may be rotatable with respect to one another, so to may the first conductive ring  332  and second conductive ring  333  be rotatable with respect to one another while maintaining contact. This physical contact may allow for an electrical connection between the sensor  331  and the receptacle  381 , which may be in further electrical connection with the projection  380  through the stab connection. To maintain these electrical connections during rotation, it may be desirable to position the first and second conductive rings  332 ,  333  within a pressure vessel as shown. 
     In some embodiments, the internal component  321  may also comprise a passage  334  therethrough alignable with another passage  335  through the protrusion  325 . These passages  334 ,  335  may allow for drilling fluid passing through a drill string to discharge through nozzles  336  within the external component  322  of the drill bit  312 . 
       FIG. 4  shows another embodiment of a drill bit  412 , this time, totally disconnected from an end of a drill string  420 . Similar to previous embodiments, the drill bit  412  of this embodiment comprises an opening  424  with an internal component  421  accessible therein. The internal component  421  comprises a pin  428  that may engage with a slot  429  within a protrusion  425  of the drill string  420 . Further, a plurality of projections  480  may be disposed generally equally spaced around a rotational axis of the protrusion  425  alignable with a plurality of receptacles  481  disposed generally equally spaced around a rotational axis of the internal component  421 . In such an arrangement, each of the plurality of receptacles  481  may be connected to an individual conductive ring (not shown) to transmit power and/or data to or from each of a plurality of sensors  431  (only one shown). 
       FIG. 5  shows an embodiment of a first drill pipe section  512  positioned proximate a second drill pipe section  520 . The first drill pipe section  512  may comprise a rotor  521  rotatable with respect to a stator  522 . The second drill pipe section  520  may comprise a protrusion  525  extending from an end thereof with a first threaded surface  526  disposed thereon. The protrusion  525  may thread into a threaded box  524  disposed on the stator  522 . As the protrusion  525  threads into the threaded box  524 , a pin  528  extending from the rotor  521  may be received within a slot  529  disposed on the protrusion  525 . The pin  528  and slot  529  combination may rotationally fix the rotor  521  to the protrusion  525 . When rotationally fixed, a projection  580  of a stab connection may align and be received within a receptacle  581  to form an electrical connection. A first conductive ring  532  and a second conductive ring  533  may form an additional electrical connection between the rotor  521  and stator  522 . 
       FIG. 6  shows an embodiment of a drill bit  612  comprising a rotor  621  with a plurality of crenellations  660  disposed thereon. A stator  622  of the drill bit  612  may be threaded onto a protrusion  625  extending from an end of a drill string  620 . The protrusion  625  may comprise a plurality of mating crenellations  661  disposed thereon. The mating crenellations  661  of the protrusion  625  may mate with the crenellations  660  of the rotor  621  to rotationally fix the rotor  621  to the protrusion  625 . While mated, projections  680  disposed on the protrusion  625  may be received within receptacles  681  disposed on the rotor  621  to form electrical connections. 
       FIGS. 7-1 and 7-2  show of an embodiment of a drill bit  712 - 1 ,  712 - 2  comprising a rotor  721 - 1 ,  721 - 2  with a slot  729 - 1 ,  729 - 2  disposed therein. A protrusion  725 - 1 ,  725 - 2  extending from an end of a drill string  720 - 1 ,  720 - 2  may comprise a pin  728 - 1 ,  728 - 2  receivable within the slot  729 - 1 ,  729 - 2  of the rotor  721 - 1 ,  721 - 2  as the drill bit  712 - 1 ,  712 - 2  is threaded onto the protrusion  725 - 1 ,  725 - 2 . The protrusion  725 - 1 ,  725 - 2  may also comprise a spring  770 - 1 ,  770 - 2  disposed thereon adjacent the pin  728 - 1 ,  728 - 2 . The spring  770 - 1 ,  770 - 2  may be capable of absorbing some of the force experienced by the pin  728 - 1 ,  728 - 2  before it finds its way into the slot  729 - 1 ,  729 - 2 . For example, as the drill bit  712 - 1 ,  712 - 2  is threaded onto the protrusion  725 - 1 ,  725 - 2 , the pin  728 - 1 ,  728 - 2  may rub against the rotor  721 - 1 ,  721 - 2  until it reaches the slot  729 - 1 ,  729 - 2  at which point it may insert itself therein. While rubbing against the rotor  721 - 1 ,  721 - 2 , the spring  770 - 1 ,  770 - 2  may compress and absorb the force of the rubbing against the pin  728 - 1 ,  728 - 2  so as not to damage the pin  728 - 1 ,  728 - 2 . 
       FIGS. 8-1 and 8-2  show an embodiment of a drill bit  812 - 1 ,  812 - 2  comprising a rotor  821 - 1 ,  821 - 2  rotationally fixable to a protrusion  825 - 1 ,  825 - 2  extending from an end of a drill string  820 - 1 ,  820 - 2 . The rotor  821 - 1 ,  821 - 2  and protrusion  825 - 1 ,  825 - 2  may be rotationally fixable by a mule shoe connection. Specifically, the protrusion  825 - 1 ,  825 - 2  may comprise a hollow cylinder  880 - 1 ,  880 - 2  that may fit around a portion of the rotor  821 - 1 ,  821 - 2 . The hollow cylinder  880 - 1 ,  880 - 2  may comprise a slit  881 - 1  disposed therein running along a length thereof. A projection  882 - 1 ,  882 - 2  may extend radially from the rotor  821 - 1 ,  821 - 2  that may fit into the slit  881 - 1  as the protrusion  825 - 1 ,  825 - 2  engages the rotor  821 - 1 ,  821 - 2 . This projection  882 - 1 ,  882 - 2 /slit  881 - 1  combination may rotationally fix the projection  882 - 1 ,  882 - 2  and rotor  821 - 1 ,  821 - 2  together while allowing them to translate axially relative to one another. 
       FIG. 9  shows an embodiment of a drill bit  912  comprising a rotor  921  rotatable with respect to a stator  922 . In this embodiment, the rotor  921  comprises a first inductive ring  990  capable of passing electrical signals via a magnetic field to a second inductive ring  991  disposed on the stator  922 . In such a configuration, electrical signals may be passed from the rotor  921  to the stator  922  while the two are rotating relative to each other while not requiring a physical connection between the two that could lead to wear. As can also be seen in this embodiment, the rotor  921  may comprise at least three inductive rings  990 ,  990 - 1 ,  990 - 2  each capable of passing a unique electrical signal. In this formation, multiple sensors  931  (only one visible) may be positioned around the drill bit  912  to take measurements from various locations and each transmit those measurements through individual inductive rings  990 ,  990 - 1 ,  990 - 2 . 
       FIG. 10  shows an embodiment of a drill bit  1012  threadably attached to an end of a drill string  1020 . The drill string  1020  may comprise a fiber optic cable  1010  passing therethrough capable of transmitting an optical signal, such as a laser, to the drill bit  1012 . The drill bit  1012  may comprise a rotor  1021  rotatable with respect to a stator  1022 . The rotor  1021  may comprise a reflective surface  1011  disposed thereon capable of directing the optical signal toward at least one sensor  1031  housed on the stator  1022 . In this configuration, the optical signal may be transmitted to the sensor  1031  as the rotor  1021  rotates relative to the stator  1022 . In other embodiments a reflective surface could be disposed on the stator with similar functionality. 
       FIG. 11  shows an embodiment of a drill bit  1112  connected to an end of a drill string  1120 . In this embodiment, the drill bit  1112  takes the form of a roller-cone type bit while previous embodiments have comprised drag type bits. It should be understood that any variety of drill bit may be chosen. Fluid may travel along the drill string  1120  in a conduit  1110  capable of passing the fluid to the drill bit  1112 . The drill bit  1112  may comprise a rotor  1121  rotatable with respect to a stator  1122 . The rotor  1121  may comprise a first circular groove  1190  disposed thereabout adjacent a second circular groove  1191  disposed about the stator  1122 . Fluid traveling along the drill string  1120  may fill the first circular groove  1190  and second circular groove  1191  allowing fluid to pass between the two as the rotor  1121  rotates relative to the stator  1122 . 
     Whereas the present invention has been described in particular relation to the drawings attached hereto, it should be understood that other and further modifications apart from those shown or suggested herein, may be made within the scope and spirit of the present invention.