Patent Publication Number: US-9428973-B2

Title: Quick-release gripping insert assembly

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority under 35 U.S.C. §119(e) to U.S. Provisional Application No. 61/820,440 filed May 7, 2013, which is incorporated herein by reference in its entirety. 
    
    
     FIELD 
     This invention relates to coiled tubing injector units. More particularly, this invention relates to gripping insert assemblies for coiled tubing injector units. 
     BACKGROUND AND SUMMARY 
     In the oil and gas industries, coiled tubing refers to metal piping used for interventions in oil and gas wells and sometimes as production tubing in depleted gas wells. Available in sizes ranging from 1 inch to 4.5 inches, coiled tubing strings are carried on reels and injected into a wellbore using a coiled tubing injector unit. A typical coiled tubing injector unit  5  is illustrated in  FIG. 1 . The typical unit includes a goose-neck support  3 , a rotary transmission assembly, parallel drive chains  7  carrying gripping insert assemblies, skates and a hydraulic system. (The transmission assembly, gripping insert assemblies, skates and hydraulic system are not shown in detail in  FIG. 1 ). Those skilled in the art are familiar with the components and operation of the unit  5  illustrated in  FIG. 1 . 
     The series of gripping insert assemblies carried by the chains provide the sole direct support for holding the coiled tubing in place or moving the tubing. The gripping insert assemblies are arranged in opposing pairs to secure the coiled tubing string between the injector-head chains. The hydraulic system applies pressure to the skates which in turn force the gripping insert assemblies toward each other thereby securing the coiled tubing between the gripping insert assemblies. Additionally, the hydraulic drive system drives the chains to feed the coiled tubing string into the well or pull the tubing out of the well. 
     A typical gripping insert assembly includes a carrier block secured to the drive chain and a gripping insert supported by the carrier block. From time to time, the gripping insert must be replaced due to damage or wear or to accommodate a change in tubing diameter or insertion of a downhole tool. Thus, a need exists for a gripping insert assembly which permits quick replacement of the gripping insert. 
     In one aspect, embodiments disclosed herein relate to a coiled tubing injector unit insert assembly including a gripping insert configured to be coupled to a carrier block, the insert comprising a tongue with a first cutout configured to engage a shaft extending within a carrier block pocket, the shaft having a first diameter portion and a second larger diameter portion and a junction between the two shaft diameters that is located within the carrier block pocket to couple the gripping insert to the carrier block. 
     In other aspects, embodiments disclosed herein relate to a coiled tubing conveying apparatus including a pair of continuous parallel drive chains revolving in a common plane, said pair of continuous drive chains having opposed, elongated parallel runs spaced apart to form a path for engaging tubing passing there through, and a plurality of gripping insert assemblies carried on each of said pair of continuous drive chains, each comprising a gripping insert configured to be coupled to a carrier block, the insert comprising a tongue with a first cutout configured to engage a shaft extending within a carrier block pocket, the shaft having a first diameter portion and a second larger diameter portion and a junction between the two shaft diameters that is located within the carrier block pocket to couple the gripping insert to the carrier block. 
     In yet other aspects, embodiments disclosed herein relate to a method of assembling a coiled tubing injector unit insert assembly including providing a gripping insert configured to be coupled to a carrier block, the insert comprising a tongue with a first cutout configured to engage a shaft extending within a carrier block pocket, the shaft having a first diameter portion and a second larger diameter portion and a junction between the two shaft diameters that is located within the carrier block pocket to couple the gripping insert to the carrier block, inserting the gripping insert tongue into the carrier block pocket until the first cutout is substantially concentrically aligned with the larger shaft diameter portion, and sliding the gripping insert in a first direction and causing the first cutout in the tongue to engage the larger shaft diameter portion, thereby coupling the gripping insert to the carrier block. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is illustrated in the accompanying drawings wherein, 
         FIG. 1  is a perspective view of a coiled tubing injector unit; 
         FIG. 2  illustrates a drive chain assembly component of  FIG. 1 ; 
         FIGS. 3A-D  illustrate a gripping insert assembly in accordance with one or more embodiments of the present disclosure; 
         FIGS. 4A-B  illustrate a carrier block of the gripping insert assembly shown in  FIGS. 3A-D ; 
         FIGS. 5A-B  illustrate a gripping insert of the gripping insert assembly shown in  FIGS. 3A-D ; 
         FIGS. 5C-D  illustrate a gripping insert of the gripping insert assembly shown in  FIGS. 3A-D ; 
         FIG. 6  illustrates a shaft of the gripping insert assembly shown in  FIGS. 3A-D ; 
         FIGS. 7A-C  illustrate steps in assembling the shaft in the carrier block of the gripping insert assembly shown in  FIGS. 3A-D ; and 
         FIGS. 8A-D  illustrate steps in assembling the gripping insert and carrier block of the gripping insert assembly shown in  FIGS. 3A-D . 
     
    
    
     DETAILED DESCRIPTION 
     The aspects, features, and advantages of the invention mentioned above are described in more detail by reference to the drawings, wherein like reference numerals represent like elements. As used herein, “longitudinal” or “longitudinally” means of or relating to length or running lengthwise. As used herein, “latitudinal” or “latitudinally” means of or relating to width or running widthwise. 
     A quick-release gripping insert assembly suitable for use in a conventional coiled tubing injector unit  5  to grasp and hold coiled tubing is disclosed.  FIG. 2  illustrates a conventional drive chain  7  of coiled tubing injector unit  5  having quick-release gripping insert assemblies attached. A pair of continuous parallel drive chains  7  revolve in a common plane and have opposed, elongated parallel runs spaced apart to form a path for engaging tubing passing there through. With reference to  FIGS. 3A-D , the quick-release gripping insert assembly  100  includes a carrier block  110  secured to the drive chain  7 , a gripping insert  140  coupled to the carrier block  110  with a shaft  170  and locked in place on the carrier block  110  with a spring plunger  190 . The gripping insert  140 , carrier block  110  and shaft  170  may be steel, or other suitable materials known to one of ordinary skill in the art. 
     Referring now to  FIGS. 4A-B , perspective views of a carrier block  110  in accordance with one or more embodiments of the present disclosure are shown. The carrier block  110  may be formed as an integral component having an upper surface  112  and extruded tongue portions  114  extending from an opposite side of the carrier block  110  and away from the upper surface  112 . In certain embodiments, the upper surface  112  may be substantially planar. Alternatively, the upper surface  112  of the carrier block may be curvilinear or curved, either latitudinally, longitudinally, or both. For example, a curved upper surface may be convex or concave. The extruded tongue portions  114  have longitudinally aligned openings  115  through which roller bearings may be installed to ride on a skate plate (not shown) of the injector head. Additionally, the carrier block  110  includes one or more circular channels  117  through which one or more pins may be installed for securing the carrier block  110  to the drive chain  7 . 
     One or more pockets  116   a ,  116   b  may be formed in the upper planar surface  112  of the carrier block  110 . The pockets  116   a ,  116   b  may be machined (e.g., using computer numerical control (“CNC”)) or integrally co-formed with the carrier block  110  (e.g., by forging or casting processes). The pockets  116   a ,  116   b  may be separated by a divider wall  118  there between. While two pockets are illustrated, in other embodiments the carrier block  110  may have a single pocket formed therein, while in still other embodiments the carrier block  110  may have more than two pockets formed therein (e.g., three or more). 
     The pockets  116   a ,  116   b  may be generally rectangular or square-shaped in a top view, although other geometries are possible as will be understood by one of ordinary skill in the art. Illustrated in  FIG. 4A , in certain embodiments, the pockets  116   a ,  116   b  may have a curved lower surface  120  which extends latitudinally and intersects the upper surface  112  at both ends of the pockets  116   a ,  116   b . Longitudinally, the pockets  116   a ,  116   b  may be defined by two opposed end surfaces  122 . The end surfaces  122  may be substantially vertical opposing surfaces that extend downward from the upper surface  112  and intersect the lower curved surface  120 . In certain embodiments, intersections between the two end surfaces  122  and the curved bottom surface  120  may be beveled or rounded. 
     Illustrated in  FIG. 4B , in other embodiments, the pockets  116   a ,  116   b  may have a substantially flat lower surface  124 . Two opposed end surfaces  122  and two opposed side surfaces  126  may extend downward from the upper surface  112  to the substantially flat lower surface  124 . In certain embodiments, the two end surfaces  122  and two side surfaces  126  may be angled (i.e., relative to the upper surface  112  and flat lower surface  124 ). In other embodiments, the two end surfaces  122  and two side surfaces  126  may be substantially vertical (i.e., perpendicular to the upper surface  112  and flat lower surface  124 ). In yet other embodiments, intersections between the two end surfaces  122 , the two side surfaces  126 , and the bottom flat surface  124  may be beveled or rounded. 
     Referring to both  FIGS. 4A-B , the carrier block  110  has a latitudinally centrally located passageway  128  that extends longitudinally from end to end through the carrier block  110 . The passageway  128  is positioned to extend longitudinally through both pockets  116   a ,  116   b . Further, the carrier block  110  includes a threaded port  130  in the upper surface  112  of the carrier block  110 . The threaded port  130  may be machined and threaded in the carrier block  110 . The threaded port  130  is located proximate to at least one of the pockets  116   a ,  116   b  for reasons that will be described in detail below. The threaded port  130  extends downward into the carrier block  110  from the upper surface  112 . 
     Referring now to  FIGS. 5A-B , perspective views of a gripping insert  140  in accordance with one or more embodiments of the present disclosure are shown. The gripping insert  140  may be formed as an integral component with an upper portion  142  of the gripping insert  140  having a channel  144  that extends in a longitudinal direction fully across the gripping insert  140  and is open at a first end  146  and a second end  148  of the gripping insert  140 . The channel  144  may be arranged and designed to grip coiled tubing. The channel  144  may be circular or may have angled flat surfaces. As shown, the channel  144  may have a plurality of transverse grooves  150  spaced longitudinally from the first end  146  to the second end  148  of the gripping insert  140 . 
     The gripping insert  140  has a lower surface  152  that is arranged and designed to contact the upper surface ( 112  in  FIGS. 4A-B ) of the carrier block  110  when the gripping insert is installed on the carrier block  110 , as will be described in more detail below. In certain embodiments, the lower surface  152  may be substantially planar corresponding to a substantially planar surface of the carrier block. Alternatively, the lower surface  152  of the gripping insert may be curvilinear or curved, either latitudinally, longitudinally, or both corresponding to a curvilinear or curved surface of the carrier block. For example, a curved lower surface may be convex or concave. Further, latitudinal lips  154  on a first end  146  and second end  148  of the gripping insert  140  may extend downward from the lower surface  152  away from the upper portion  142  of the gripping insert  140 . The latitudinal lips  154  are arranged and designed to extend downward past the upper surface ( 112  in  FIGS. 4A-B ) of the carrier block  110  when the gripping insert  140  is installed on the carrier block  110 . 
     Further, the gripping insert  140  includes one or more extruded tongue portions  156   a ,  156   b  that extend downward from the lower surface  152  away from the upper portion  142 . The extruded tongues  156   a ,  156   b  may be longitudinally positioned on the lower surface  152  of the gripping insert  140 . In certain embodiments, the extruded tongue portions  156   a ,  156   b  may be formed integrally with the upper portion  142 . In other embodiments, the extruded tongue portions  156   a ,  156   b  may be welded to the lower surface  152  of the gripping insert  140 . The one or more extruded tongue portions  156   a ,  156   b  are arranged and designed to correspond with and engage the one or more pockets  116   a ,  116   b  formed in the upper surface  112  of the carrier block  110 , as will be described below in more detail. The extruded tongue portions  156   a ,  156   b  may be arranged and designed having a thickness in the latitudinal direction that is substantially equal to half of a distance between end surfaces  122  of pockets  116   a ,  116   b . In alternative embodiments, the extruded tongue portions  156   a ,  156   b  may have any latitudinal thickness. The extruded tongue portions  156   a ,  156   b  may be longitudinally located at a central portion of the lower surface  152  of the gripping insert  140 . 
     As illustrated in  FIG. 5A , in certain embodiments, the extruded tongue portions  156   a ,  156   b  may have a semi-circular cross-section (longitudinally), which corresponds with a geometry of the pockets  116  in the carrier block  110  having a lower curved surface  120  (shown in  FIG. 4A ). As illustrated in  FIG. 5B , in other embodiments, the extruded tongue portions  156   a ,  156   b  may have a square-like or rectangular cross-section (longitudinally), which corresponds with a geometry of pockets  116  in the carrier block  110  having a flat bottom surface  124  (shown in  FIG. 4B ). Other corresponding tongue and pocket configurations and geometries are also possible and will be understood by one of ordinary skill in the art. 
       FIGS. 5C-D  illustrate a gripping insert  140  having tongue portions  156   a ,  156   b  which are attached or coupled to the lower surface  152  of the gripping insert  140 . Tongue portions  156   a ,  156   b  fit within a recess  143  machined or otherwise formed in the lower surface  152  of the gripping insert  140 . One or more threaded fasteners  157  may be used to secure the tongue portions  156   a ,  156   b  to the gripping insert  140 . 
     Referring to  FIGS. 5A-D , the tongue portions  156   a ,  156   b  have a centrally located first cutout  158 . In certain embodiments, the first cutout may be circular. Alternatively, the first cutout may be polygonal or non-circular. The first cutout  158  has a diameter that is substantially equal to a diameter of the passageway  128  through the carrier block  110 . The tongue portions  156   a ,  156   b  further include a peripheral cutout  160  that extends from the first cutout  158  to a distal end or edge of the tongue portions  156   a ,  156   b . The peripheral cutout  160  has a width that is less than a diameter of the first cutout  158 . 
     Referring now to  FIG. 6 , a perspective view of a shaft  170  in accordance with one or more embodiments of the present disclosure is shown. The shaft  170  may be a circular rod that is arranged and designed to be inserted into the passageway  128  extending longitudinally through the carrier block  110 . Alternatively, the shaft may have a polygonal or non-circular cross-section. A cross-sectional geometry of the shaft should correspond to a cross-sectional geometry of passageway  128  ( FIGS. 4A-B ) and first cutout  158  ( FIGS. 5A-D ). The shaft  170  may be solid or hollow longitudinally there through. A first end portion  172 , a second end portion  174 , and a central portion  176  of the shaft  170  have a first diameter, which substantially corresponds with an outer diameter of the passageway  128  extending longitudinally through the carrier block  110 , and an outer diameter of the first cutout  158  in the extruded tongue portions  156   a ,  156   b  of the gripping insert  140 . A first intermediate portion  178  and a second intermediate portion  180  of the shaft  170  have a second diameter, which substantially corresponds with a dimension of the peripheral cutout  160  of the extruded tongue portions  156   a ,  156   b  of the gripping insert  140 . The second diameter is less than the first diameter. 
     Referring to  FIGS. 6 and 7B , in certain embodiments, when the shaft  170  is inserted within the passageway  128  of the carrier block  110 , a first end portion  172  of the shaft  170  extends longitudinally within the passageway  128  from a first end of the carrier block  110  to substantially the center of the first pocket  116   a . In other embodiments, the first end portion may extend longitudinally within one-quarter length of the pocket, or within three-quarters length of the pocket, or other pocket lengths. 
     A central portion  176  of the shaft  170  extends longitudinally within the passageway  128  in the divider wall  118  from a second end of the first pocket  116   a  to substantially the center of the second pocket  116   b . In other embodiments, the central portion may extend longitudinally within one-quarter length of the pocket, or within three-quarters length of the pocket, or other pocket lengths. 
     A second end portion  174  of the shaft  170  extends longitudinally within the passageway  128  from a second end of the second pocket  116   b  to a second end of the carrier block  110 . A first intermediate portion  178  of the shaft  170  extends from substantially the center of the first pocket  116   a  to the second end of the first pocket  116   a  (i.e., where divider wall  118  begins). A second intermediate portion  180  of the shaft  170  extends from substantially the center of the second pocket  116   b  to the second end of the second pocket  116   b . As shown, the first intermediate portion  178  and the second intermediate portion  180  of the shaft  170  extend longitudinally only within the first and second pockets  116   a ,  116   b , respectively. That is, an interface between said first and second diameters is longitudinally disposed within said pocket. 
     As shown in  FIGS. 3B and 7C , the spring plunger  190  is a commonly used spring-loaded device that will be known to one of ordinary skill in the art. The spring plunger  190  includes a hollow cylindrical body with external threads that engage internal threads of the port  130  in the planar upper surface of the carrier block. A plunger member is disposed within the hollow cylindrical body along with a spring (of any kind), which biases the plunger within the hollow cylindrical body in one direction, so that an end or tip of the plunger member extends beyond the cylindrical body. Accordingly, the plunger member may be depressed (against the spring) so that the end of the plunger member is longitudinally aligned with an end of the cylindrical body. When released, the end of the plunger member extends longitudinally past the end of the cylindrical body. 
     In one aspect, embodiments disclosed herein relate to a gripping insert assembly used in a coiled tubing injector unit including a carrier block having an upper surface, at least one pocket formed in said upper surface, and a passageway substantially latitudinally centered and extending longitudinally there through, a shaft corresponding to a cross-section of said passageway of said carrier block, said shaft including at least a first end portion and a central portion having a first shaft diameter, and an intermediate portion having a second shaft diameter, wherein said first shaft end portion extends longitudinally within said pocket, and wherein said intermediate shaft portion extends longitudinally within said pocket, and a gripping insert having at least one tongue portion corresponding to said pocket in said upper surface of said carrier block, wherein said tongue portion comprises a first cutout substantially corresponding to said first shaft diameter, and a second cutout substantially corresponding to said second shaft diameter. 
     Methods of assembling the gripping insert and the carrier block is a two-step process: first the shaft is installed into the carrier block (shown in  FIGS. 7A-C ), then the gripping insert is coupled with the carrier block (shown in  FIGS. 8A-D ). Referring to  FIGS. 7A-C ), the shaft  170  is inserted into the passageway  128  of the carrier block  110  so that ends of the shaft  170  are flush with ends of the carrier block  110  ( FIG. 7A ). The carrier block  110  is then installed between the drive chains  102  ( FIG. 7B ). Next, the spring plunger  190  is installed into the port  130  in the planar upper surface of the carrier block  110  ( FIG. 7C ). The plunger  190  may be threaded, or alternatively may be press fit or otherwise within the port  130 . 
     Referring to  FIGS. 8A-D , to couple the gripping insert  140  with the carrier block  110 , extruded tongue portions of the gripping insert  140  are longitudinally aligned with pockets of the carrier block  110 , and more particularly with first and second intermediate portions of the shaft  170  that extend longitudinally within pockets (i.e., intermediate portions having the smaller diameter). Extruded tongues of the gripping insert  140  are vertically inserted (as indicated by arrow A) into the pockets of the carrier block  110  until the planar bottom surface of the gripping insert  140  contacts and sits flush with the planar upper surface of the carrier block  110  ( FIG. 8A ). Lips  154  ( FIGS. 5A-B ) extend downward past the planar upper surface of the carrier block and provide alignment and indication that the gripping insert  140  is properly engaged with the carrier block  110 . The planar bottom surface of the gripping insert  140  also depresses the spring plunger  190  flush with the planar upper surface of the carrier block  110 . During vertical installation of the gripping insert  140 , the peripheral cutouts in the extruded tongues initially engage the first and second intermediate portions of the shaft  170 . Subsequently, when the planar bottom surface of the gripping insert  140  contacts the planar upper surface of the carrier block  110 , the first and second intermediate portions of the shaft  170  are concentrically positioned within the circular cutouts (having a first diameter) of the extruded tongues. 
     The gripping insert  140  is then horizontally moved (indicated by arrow B) to engage the circular cutouts of the extruded tongue portions with the first end portion and central end portion (both having a first diameter) of the shaft  170  extending within the pockets ( FIG. 8B ). Engagement of the circular cutouts with the first diameter portions of the shaft  170  precludes vertical movement of the gripping insert (indicated by arrow A). The gripping insert  140  is slid horizontally until the extruded tongues contact end surfaces of the first and second pockets, at which point a full width of the extruded tongues is engaged with the first diameter portions of the shaft  170  within the pockets. 
     Also, spring plunger  190 , which was depressed within the port by the planar lower surface of the gripping insert  140 , is biased upward and locks the gripping insert  140  in place ( FIG. 8C-D ). Particularly, an end of the plunger member is biased upward by the internal spring to a position above the planar upper surface of the carrier block  110 , which prevents the gripping insert from moving in a horizontal direction (indicated by arrow B). 
     Quick disassembly of decoupling of the gripping insert  140  from the carrier block  110  proceeds in a manner opposite of assembly. The spring plunger  190  is depressed to allow the gripping insert  140  to slide horizontally (opposite of the direction indicated by arrow B) to move the circular cutouts in extruded tongues into longitudinal alignment over the first and second intermediate portions of the shaft  170 . Then, the gripping insert  140  is lifted vertically (opposite the direction indicated by arrow A) to allow second cutouts of the extruded tongues to pass over and disengage from the first and second intermediate portions of the shaft  170 . 
     In certain aspects, embodiments disclosed herein relate to a method of assembling a gripping insert assembly including providing said gripping insert assembly including a carrier block having an upper surface, one or more pockets formed in said upper surface, and a passageway latitudinally centered and extending longitudinally there through, a shaft arranged and designed to be inserted within said passageway of said carrier block, said shaft including a first end portion, a second end portion, and central portion having a first shaft diameter, and a first intermediate portion and a second intermediate portion having a second shaft diameter, and a gripping insert having a lower surface and one or more tongue portions corresponding to said one or more pockets in said upper surface of said carrier block, wherein said tongue portions include a circular cutout corresponding with said first shaft diameter, and a peripheral cutout corresponding with said second shaft diameter. The method further includes inserting the shaft within said passageway of said carrier block, wherein said first shaft end portion and first intermediate shaft portion extend longitudinally within said pocket, and wherein said central shaft portion and second intermediate shaft portion extend longitudinally within said pocket, inserting said tongue portions of said gripping insert into said pockets of said carrier block until said lower surface of said gripping insert contacts and sits flush with said upper surface of said carrier block, wherein said tongue portions engage said first and second intermediate shaft portions, and sliding said gripping insert horizontally until said tongue portions are longitudinally aligned with said first shaft end portion and central portions. 
     Advantageously, embodiments disclosed herein for quick-release gripping inserts reduces time required to replace the gripping inserts in a number of situations. For example, gripping inserts may be replaced to use different sizes of coiled tubing based on particular applications. Additionally, gripping inserts may need to be replaced due to wear or damage. Accordingly, rig downtime due to maintenance or replacement of gripping inserts is greatly reduced, which in turn reduces costs and increases productivity of the coiled tubing operation. 
     The claimed subject matter is not to be limited in scope by the specific embodiments described herein. Indeed, various modifications of the invention in addition to those described herein will become apparent to those skilled in the art from the foregoing description. Such modifications are intended to fall within the scope of the appended claims.