Abstract:
A curved nozzle for use in a drill bit is disclosed. The curved nozzle includes a flow path that directs drilling fluid towards the face of cutters. The curved nozzle may include a base, neck, and a tip. Flow entering the nozzle, travels along a flow path through the nozzle and out the tip. The flow path may be reduced as it passes through the nozzle. The flow is curved as it flows through the neck and out the tip. The nozzle includes cooperating interior surfaces that guide the flow. The upper interior surface may include two curved zones. The first zone will be a substantially constant radius of curvature. The second zone, extending from the first zone, may be straight.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates generally to downhole tools used in subterranean drilling, and more particularly, to curved nozzle used in downhole tools. 
       BACKGROUND OF THE INVENTION 
       [0002]    Drill bits are commonly used for drilling bore holes or wells in earth formations. One type of drill bit is a fixed cutter drill bit which typically includes a plurality of cutting elements, or cutters, disposed within a respective cutter pocket formed within one or more blades of the drill bit and one or more nozzle sockets formed within the drill bit. 
         [0003]      FIGS. 1 and 2  show a drill bit  100 , or fixed cutter drill bit  100 , in accordance with the prior art. Referring to  FIG. 1 , the drill bit  100  includes a bit body  110  that is coupled to a shank  115  and is designed to rotate in a counter-clockwise direction  190 . The shank  115  includes a threaded connection  116  at one end  120 . The threaded connection  116  couples to a drill string (not shown) or some other equipment that is coupled to the drill string. The threaded connection  116  is shown to be positioned on the exterior surface of the one end  120 . This positioning assumes that the drill bit  100  is coupled to a corresponding threaded connection located on the interior surface of a drill string (not shown). However, the threaded connection  116  at the one end  120  is alternatively positioned on the interior surface of the one end  120  if the corresponding threaded connection of the drill string, or other equipment, is positioned on its exterior surface in other exemplary embodiments. A bore (not shown) is formed longitudinally through the shank  115  and extends into the bit body  110  forming a plenum  310  ( FIG. 4 ), which communicates drilling fluid during drilling operations from within the bit body  110  to a drill bit face  111  via one or more nozzle sockets  114  formed within the bit body  110 . These nozzle sockets  114  are cylindrically shaped within the drill bit  100 . 
         [0004]    The bit body  110  includes a plurality of gauge sections  150  and a plurality of blades  130  extending from the drill bit face  111  of the bit body  110  towards the threaded connection  116 , where each blade  130  extends to and terminates at a respective gauge section  150 . The blade  130  and the respective gauge section  150  are formed as a single component, but are formed separately in certain other drill bits  100 . The drill bit face  111  is positioned at one end of the bit body  110  furthest away from the shank  115 . The plurality of blades  130  form the cutting surface of the drill bit  100 . One or more of these plurality of blades  130  are either coupled to the bit body  110  or are integrally formed with the bit body  110 . The gauge sections  150  are positioned at an end of the bit body  110  adjacent the shank  115 . The gauge section  150  includes one or more gauge cutters (not shown) in certain drill bits  100 . The gauge sections  150  typically define and hold the full hole diameter of the drilled hole. Each of the blades  130  and gauge sections  150  include a leading edge section  152 , a face section  154 , and a trailing edge section  156 . The face section  154  extends from one end of the trailing edge section  156  to an end of the leading edge section  152 . The leading edge section  152  faces in the direction of rotation  190 . The blades  130  and/or the gauge sections  150  are oriented in a spiral configuration according to some of the prior art. However, in other drill bits, the blades  130  and/or the gauge sections  150  are oriented in a non-spiral configuration. A junk slot  122  is formed, or milled, between each consecutive blade  130 , which allows for cuttings and drilling fluid to return to the surface of the wellbore (not shown) once the drilling fluid is discharged from the nozzle sockets  114  during drilling operations. 
         [0005]    A plurality of cutters  140  are coupled to each of the blades  130  within a respective cutter pocket  160  formed therein. The cutters  140  are generally formed in an elongated cylindrical shape; however, these cutters  140  can be formed in other shapes, such as disc-shaped or conical-shaped. The cutters  140  typically include a substrate  142 , oftentimes cylindrically shaped, and a cutting surface  144 , also cylindrically shaped, disposed at one end of the substrate  142  and oriented to extend outwardly from the blade  130  when coupled within the respective cutter pocket  160 . The cutting surface  144  can be formed from a hard material, such as bound particles of polycrystalline diamond forming a diamond table, and be disposed on or coupled to a substantially circular profiled end surface of the substrate  142  of each cutter  140 . Typically, the polycrystalline diamond cutters (“PDC”) are fabricated separately from the bit body  110  and are secured within a respective cutter pocket  160  formed within the bit body  110 . Although one type of cutter  140  used within the drill bit  100  is a PDC cutter; other types of cutters also are contemplated as being used within the drill bit  100 . These cutters  140  and portions of the bit body  110  deform the earth formation by scraping and/or shearing depending upon the type of drill bit  100 . 
         [0006]    For steel bits, the nozzle sockets  114  are machined into the drill bit  100 . Nozzle sockets are formed using apparatuses and methods known to people having ordinary skill in the art and will not be described in detail herein for the sake of brevity. 
         [0007]      FIG. 3A  shows a cross-sectional side view a nozzle  210  coupled within the nozzle socket  114  in accordance with the prior art.  FIG. 3B  shows a top view of the nozzle  210  coupled within the nozzle socket  114  in accordance with the prior art. Referring to  FIGS. 3A-3B , the nozzle socket  114  includes a nozzle socket base  230  and a nozzle socket wall  235  extending perpendicularly away from the perimeter of the nozzle socket base  230 , thereby forming a cylindrically-shaped cavity  237  therein. Hence, the nozzle socket  114  also is cylindrically shaped. The nozzle  210  is inserted through the nozzle socket  114  and coupled to the bit body  110  ( FIG. 1 ) adjacent the nozzle socket base  230 . Although not illustrated, the nozzle  210  is coupled to the bit body  110  ( FIG. 1 ) using a snap-fit, threaded connection, or other method and/or device known to people having ordinary skill in the art. 
         [0008]    As previously mentioned, the bore is formed within the shank  115  and extends into the bit body  110  forming the plenum  310 .  FIG. 4  shows flow paths from the bit  100  to nozzle sockets  114 . The bore allows for drilling fluid to flow from within the drill string into the drill bit  100 . The flow tubes  320  in the bit body allow drilling fluid to flow from within the plenum  310  to nozzle sockets  114 . In the embodiment shown in  FIGS. 1 and 2 , the fluid reaching the nozzle sockets is sprayed into the well by the nozzles  210 . The spray of drilling fluid through the nozzle  210 , which are positioned at the drill bit face  111 , facilitates removal of the cuttings from the drill bit face  111  and moves them back towards the surface of the ground. The nozzle sockets  114 , as previously mentioned, are often cylindrically shaped, i.e., have a nozzle socket wall  235  that forms a cylindrical shape. Although four nozzle sockets  114  are illustrated as being formed within the drill bit  100 , greater or fewer nozzle sockets  114  are formed in other drill bits  100 . 
         [0009]    During drilling of a borehole, the drill bit  100  rotates to cut through an earth formation to form a wellbore therein. This cutting is typically performed through scraping and/or shearing action according to certain drill bits  100 , but is performed through other means based upon the type of drill bit used. Drilling fluid (not shown) exits the drill bit  100  through one or more nozzles  210  and facilitates the removal of the cuttings from the borehole wall back towards the surface. As the drill bit  100  rotates and the drilling fluid with cuttings are at the bottom of the borehole, some cuttings adhere to the drill bit  100  causing inefficiencies. Thus, the nozzles  210  facilitate removal of portions of these cutting that are adhered to the drill bit  100 . 
         [0010]    High angle nozzles, or high angle nozzle sockets, also known as lateral jets, are known in the drill bit casting art. However, they are difficult to incorporate into machined bits, such as steel bits, due to the constraints in the manufacturing process. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The foregoing and other features and aspects of the invention may be best understood with reference to the following description of certain exemplary embodiments, when read in conjunction with the accompanying drawings, wherein: 
           [0012]      FIG. 1  shows a perspective view of a fixed cutter drill bit in accordance with the prior art; 
           [0013]      FIG. 2  shows a top view of convention drill bit. 
           [0014]      FIG. 3A  shows a cross-sectional side view a conventional nozzle positioned within the nozzle socket of  FIG. 1  in accordance with the prior art; 
           [0015]      FIG. 3B  shows a top view of the conventional nozzle positioned within the nozzle socket of  FIG. 1  in accordance with the prior art; 
           [0016]      FIG. 4  shows flow paths of an typical bit; 
           [0017]      FIG. 5  shows a front view of a curved nozzle; 
           [0018]      FIG. 6  shows a rotated view of a curved nozzle; 
           [0019]      FIG. 7  shows a cut-away, side view of a curved nozzle; 
           [0020]      FIG. 8  shows a close-up of a curved nozzle tip; 
           [0021]      FIG. 9  shows a perspective view a sleeve retainer; 
           [0022]      FIG. 10  shows a cut-away view of a sleeve retainer; 
           [0023]      FIG. 11  shows a partial perspective view of the installation of a curved nozzle in a drill bit; 
           [0024]      FIG. 12A  shows a cut-away view of a drill bit with conventional nozzles; 
           [0025]      FIG. 12B  shows the jet spray from a conventional nozzle; 
           [0026]      FIG. 13A  shows a cut-away view of a drill bit with a curved nozzle; 
           [0027]      FIG. 13B  shows the jet spray from a curved nozzle; 
           [0028]      FIG. 14A  shows a top view of a drill bit with curved nozzles; and 
           [0029]      FIGS. 14B  and C show jet spray from curved nozzles. 
       
    
    
       [0030]    The drawings illustrate only exemplary embodiments of the invention and are therefore not to be considered limiting of its scope, as the invention may admit to other equally effective embodiments. 
       DETAILED DESCRIPTION OF INVENTION 
       [0031]    The present invention is directed to downhole tools used in subterranean drilling. In particular, the application is directed to curved nozzles positionable within downhole tools. Although the description of exemplary embodiments is provided below in conjunction with a fixed cutter drill bit, similar to that shown in  FIG. 1 , alternate exemplary embodiments of the invention may be applicable to other types of downhole tools having nozzle sockets, including, but not limited to, PDC drill bits, roller cone bits, and any other downhole tool that includes one or more nozzle sockets. The present invention may be better understood by reading the following description of non-limiting, exemplary embodiments with reference to the attached drawings, wherein like parts of each of the figures are identified by like reference characters, and which are briefly described as follows. 
         [0032]      FIGS. 5 and 6  show one embodiment of a curved nozzle  500 . Curved nozzle  500  includes a base  510  and neck  520 . In one embodiment, the base  510  is sized and shaped to fit within a sleeve retainer  900  ( FIG. 9 ) that secures the curved nozzle  500  into bit  100 . In the embodiment of  FIGS. 5 and 6 , the base  510  is cylindrical and generally smooth. The smoothness of the base  510  facilitates nozzle orientation during installation. For example, curved nozzle  500  can be rotated within sleeve retainer  900  before the sleeve retainer  900  is secured within bit  100 . In alternative embodiments, the base  510  can threaded or otherwise configured so that it can be secured directly into bit  100  without a retaining sleeve. In yet another embodiment, the base  510  of curved nozzle  500  may be indexed so that it fits within a matching shape in bit  100 , thereby ensuring a pre-determined orientation. Once positioned, the curved nozzle  500  can be secured in position using a sleeve retainer  900  or other means. The wall thickness of base  510  is suitable for mounting the curved nozzle  500  in bit  100 . 
         [0033]    In the embodiment shown in  FIGS. 5 and 6 , neck  520  extends from base  510 . The outer diameter of neck  520  is shown as being smaller than the outer diameter of the base  510 . However, neck  520  may be the same size or larger than base  510 . In the embodiment shown, neck  520  is roughly the same length as base  510 . However, the base  510  and neck  520  may be a different length. Alternatively, curved nozzle  500  may not have a neck  520 . In the embodiment shown, curved nozzle  500  includes a step  530  at the top of base  510 . 
         [0034]    Base  510  and neck  520  are shown as being a single piece. However, base  510  and neck  520  may be separate pieces joined together, either permanently or removably. Further, base  510  and neck  520  can be made of the same or different material. In one embodiment, curved nozzle  500  is made out of sintered tungsten carbide 
         [0035]      FIG. 7  shows a side, cut-away view of nozzle  500 . From  FIG. 7 , it can be seen that curved nozzle  500  includes a fluid pathway  1200  that connects to flow tube  320 . The fluid pathway  1200  includes a transition zone  700 , throat  710 , and curved tip  720 . The transition zone  700  is positioned between the flow tube  320  and the neck  520 . In the embodiment shown, the cross sectional area of the transition zone  700  decreases from the cross sectional area of flow tube  320  to the cross sectional area of the throat  710 . In a preferred embodiment, the transition is smooth in order to minimize energy loses in the fluid stream, such as losses due to sudden directional changes in the flow path, or configurations that increase flow turbulence. However, the transition zone  710  may be a step or series of small steps. Further, transition zone  710  is shown as being generally symmetrical. However, it may be symmetrical or non-symmetrical. 
         [0036]    The throat  710  is the point along the flow path with the smallest cross-sectional area. In the embodiment shown in  FIG. 7 , the throat  710  includes a length that has a constant cross-sectional area. In other embodiments, however, the throat  710  may be a single point along the length of the nozzle.  FIG. 7  shows the transition zone  700  entirely within base  510 . However, the transition zone may extend into the throat  710 . 
         [0037]    The ratio between the cross-sectional area of the flow tube  320  and the cross-sectional area of the throat  710  is determined based in part on fluid supply pressure and the desired flow velocity of the fluid exiting the nozzle  500 . 
         [0038]    In the embodiment shown, the direction of flow is constant through the flow tubes, base  510  and neck  520  of curved nozzle  500 . However, it is understood that some slight directional change from plenum  320  may occur. 
         [0039]    Fluid pathway  1200  through curved nozzle  500  extends from the base to the curved tip  720 . The curved tip  720  is shaped to angularly deflect flow from the direction it is flowing at the throat  710 . In the embodiment shown, curved tip  720  deflects flow approximately 35 degrees. However, other deflection amounts are contemplated. 
         [0040]    According to some exemplary embodiment, the curved tip  720  has an upper top surface  730  and lower top surface  740 . Shaped region  750  connects the upper and lower top surfaces. 
         [0041]      FIG. 8  shows a close-up of one embodiment of the curved tip  720 . The curved tip includes an upper curved surface  860  and lower curved surface  870 . According to one embodiment, the upper curved surface  860  includes two distinct curved zones. The first curved zone  880  smoothly transitions from the throat  710  to a second curved zone  890 . The second curved zone  890  directs the flow from the first curved zone  880  to the final exit angle. In the embodiment shown in  FIG. 8 , second curved zone  890  is a straight. However, the second curved zone  890  may be a curved surface. As noted with respect to the embodiment shown, the final exit angle is approximately 35 degrees. The second curved zone  890  is supported by the structure that also forms the upper surface  730 . The first curved zone  880  and the lower curved surface  870  may have a similar, but opposite, radius of curvature. In one embodiment, a line extended perpendicular to the point in which the lower curved surface  870  meets the lower top surface  740  intersects the upper curved surface  860  at approximately the point in which the first curved zone  880  transitions into the second curved zone  890 . 
         [0042]    Although the curved tip of the embodiment shown in  FIG. 8  has first and second curved zones ( 880  and  890 ), other configurations are contemplated. For example, the directional change from the throat may be smooth, having a constant or near constant radius of curvature. Alternatively, it may have sections with different radii of curvature. Further, instead of a constant radius of curvature, the upper curved surface  860  may include a series of short straight sections that are each angled slightly from the preceding straight section. Still further, the upper curved surface  860  may be combinations of straight and curved sections. 
         [0043]    Lower curved surface  870  includes a slight curvature. Like the upper curved surface  860 , it may have a single radius of curvature or multiple. Further, instead of a constant radius of curvature, the lower curved surface may include a series of short straight sections that are each angled slightly from the preceding straight section. Still further, the lower curved surface  860  may be combinations of straight and curved sections. 
         [0044]      FIG. 9  shows perspective view of sleeve retainer  900 . Sleeve retainer  900  is configured to secure nozzle  500  in bit  100 . In the embodiment shown, sleeve retainer  900  is threaded to match interior threads in bit  100 . However, one skilled in the art understands that other ways of securing sleeve retainer  900  are available. 
         [0045]    Sleeve retainer  900  also includes a top edge  910  shaped to assist in installation. For example, a tool can fit within the notches shown to tighten or loosen the sleeve retainer  900 . 
         [0046]      FIG. 10  shows a cut-away, side view of sleeve retainer  900 . The sleeve retainer  900  has an inner area  920  that is sized and shaped to receive nozzle  500 . In one embodiment, inner area  920  is sized and shaped to receive the base  510  of curved nozzle  500 . Inner area  920  also includes shoulder  930 . The shoulder  930  engages the step  530  between the base  510  and neck  520  of curved nozzle  500 . In a preferred embodiment, the shoulder  930  engages step  530  before the sleeve retainer  900  bottoms out in the nozzle socket  114 . In this way, the bottom of curved nozzle  500  is pressed firmly against bit  100 , or alternatively, against a gasket  1100  between the bottom of curved nozzle  500  and bit  100 . In one embodiment, the inner area  920  is sized to have a frictional fit with curved nozzle  500 . In this manner, the curved nozzle  500  may be rotated within retainer sleeve  900  prior to retainer sleeve  900  being tightened into its final position. Although a frictional fit is preferred, the inner area  920  and base  510  may be sized for an interference fit or a loose fit. 
         [0047]      FIG. 11  shows an exploded view of bit  100  showing how curved nozzle  500  is installed. Curved nozzle  500  is positioned on gasket  1100  within nozzle socket  114 . In one embodiment, the body and gasket  1100  are made out of the same material. The curved nozzle  500  is oriented as desired. In a preferred embodiment, curved nozzle  500  is positioned to direct fluid along the cutting surfaces  144  of cutters  140  on one blade  130 . Once oriented as desired, the sleeve retainer  900  is positioned over the nozzle and tightened to secure the curved nozzle  500  in bit  100 . In one embodiment, the threads of sleeve retainer  900  are identical to conventional nozzle threads. 
         [0048]      FIGS. 12A  and B show cross sections of bit  100  with conventional nozzles  210 . The conventional nozzles  210  are positioned within nozzle socket  114  so that the nozzles do not extend above the water way  1200 .  FIG. 12B , shows the jet spray pattern  1210  from a conventional nozzle  210 . As can be seen, the jet spray pattern  1210  extends in the axial direction of conventional nozzle  210 . 
         [0049]      FIGS. 13A  and B show cross sections of bit  100  with a curved nozzle  500 . In a preferred embodiment, curved nozzle  500  extends into the water way  1200  when installed in bit  100 . The jet spray pattern  1300  from curved nozzle  500  extends in the direction established by nozzle tip  720 . As noted previously, the jet spray is angled from the flow direction entering the base of curved nozzle  500  by approximately 35 degrees. The curved nozzle  500  is positioned to direct its jet spray away from the axis of the bit  100  and along the cutting surfaces  144  of cutters  140 . 
         [0050]      FIG. 14A  shows bit  100  with curved nozzles  500  installed. As can also be seen from  FIG. 14A , a bit  100  can be configured with both conventional nozzles  210  and curved nozzles  500 . In the embodiment shown in  FIG. 14A , the inner three nozzles are curved nozzles  500 . However, one skilled in the art understands that various combinations are contemplated. For example, a bit  100  may be configured with all curved nozzles  500 . 
         [0051]      FIGS. 14B  and C show views of bit  100  with spray patterns included. Each is oriented to direct its corresponding spray patter  1300  along the cutting surfaces  144  of cutters  114 . In this manner, cuttings from the well are more efficiently guided along junk slots  122  and away from the tip of bit  100 . 
         [0052]    Although each exemplary embodiment has been described in detailed, it is to be construed that any features and modifications that is applicable to one embodiment is also applicable to the other embodiments. 
         [0053]    Although the invention has been described with reference to specific embodiments, these descriptions are not meant to be construed in a limiting sense. Various modifications of the disclosed embodiments, as well as alternative embodiments of the invention will become apparent to persons of ordinary skill in the art upon reference to the description of the exemplary embodiments. It should be appreciated by those of ordinary skill in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures or methods for carrying out the same purposes of the invention. It should also be realized by those of ordinary skill in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims. It is therefore, contemplated that the claims will cover any such modifications or embodiments that fall within the scope of the invention.