Patent Publication Number: US-11028654-B2

Title: Roller coupling apparatus and method therefor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of and claims benefit to U.S. application Ser. No. 16/520,046, entitled “ROLLER COUPLING APPARATUS AND METHOD THEREFOR,” which was filed on Jul. 23, 2019 in the name of the inventor herein and which is incorporated herein in full by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention generally relates to oil pumps and couplings used therein and, more specifically, to a roller coupling apparatus and related method therefor. 
     BACKGROUND OF THE INVENTION 
     In general terms, an oil well pumping system begins with an above-ground pumping unit, which creates the up and down pumping action that moves the oil (or other substance being pumped) out of the ground and into a flow line, from which the oil is taken to a storage tank or other such structure. 
     Below ground, a shaft or “wellbore” is lined with piping known as “casing.” Into the casing is inserted piping known as “tubing.” A string of sucker rods is inserted into the tubing. The string of sucker rods typically includes multiple individual sucker rods, which are typically 25-28 feet in length each. In addition, the rod string can include pony rods (also known as shooter rods, pups, and rod subs), which are sucker rods that are less than 25 feet in length. Pony rods can be of different lengths, such as two, four, six, or eight feet in length. The individual sucker rods are joined together with couplings to form the sucker rod string. According to American Petroleum Institute (API) specifications, such couplings are 4.5 to 5 inches in length. Standard couplings may typically be 4-6 inches in length. The sucker rod string can be up to or more than one mile in length and is ultimately, indirectly coupled at its north end to the above-ground pumping unit. The string of sucker rods is coupled at its south end indirectly to the subsurface oil pump itself, which is also located within the tubing, which is sealed at its base to the tubing. The sucker rod string couples to the oil pump at a coupling known as a 3-wing cage. A sinker bar, which is heavily-weighted to help maintain the tension in the sucker rod string particularly on the downstroke, can be positioned directly above the subsurface oil pump. 
     The subsurface oil pump has a number of basic components, including a barrel and a plunger. The plunger operates within the barrel, and the barrel, in turn, is positioned within the tubing. The north end of the plunger is typically connected to a valve rod or hollow valve rod, which moves up and down to actuate the pump plunger. The valve rod or hollow valve rod typically passes through a valve rod guide. 
     Beginning at the south end, subsurface oil pumps generally include a standing valve, which has a ball therein, the purpose of which is to regulate the passage of oil (or other substance being pumped) from downhole into the pump, allowing the pumped matter to be moved northward out of the system and into the flow line, while preventing the pumped matter from dropping back southward into the hole. Oil is permitted to pass through the standing valve and into the pump by the movement of the ball off of its seat, and oil is prevented from dropping back into the hole by the seating of the ball. 
     North of the standing valve, coupled to the sucker rod, is a traveling valve. The purpose of a conventional traveling valve is to regulate the passage of oil from within the pump northward in the direction of the flow line, while preventing the pumped oil from slipping back down in the direction of the standing valve and hole. 
     In use, oil is pumped from a hole through a series of “downstrokes” and “upstrokes” of the oil pump, wherein these motions are imparted by the above-ground pumping unit. During the upstroke, formation pressure causes the ball in the standing valve to move upward, allowing the oil to pass through the standing valve and into the barrel of the oil pump. This oil will be held in place between the standing valve and the traveling valve. In the conventional traveling valve, the ball is located in the seated position. It is held there by the pressure from the oil that has been previously pumped. The oil located above the traveling valve is moved northward in the direction of the 3-wing cage at the end of the oil pump. 
     During the downstroke, the ball in the conventional traveling valve unseats, permitting the oil that has passed through the standing valve to pass therethrough. Also during the downstroke, the ball in the standing valve seats, preventing the pumped oil from slipping back down into the hole. 
     The process repeats itself again and again, with oil essentially being moved in stages from the hole, to above the standing valve and in the oil pump, to above the traveling valve and out of the oil pump. As the oil pump fills, the oil passes through the 3-wing cage and into the tubing. As the tubing is filled, the oil passes into the flow line, from which the oil is taken to a storage tank or other such structure. 
     Unlike typical wellbores of the past, which are typically drilled in relatively straight vertical lines, a current drilling trend is for wellbores to be drilled vertically in part and then horizontally in part, resulting in wellbores that have some curvature or “deviation.” Such wells may commonly be referred to as “deviated” wells. When drilling deviated wells, drillers typically drill vertically for some distance (e.g. one mile), through the upper zone and down to the bedrock, and then transition to drilling horizontally. One advantage to drilling wellbores in this configuration is that the horizontal area of the well typically has many more perforations in the casing, which allows for more well fluid to enter the wellbore than with typical vertical casing wells. This, in turn, allows for more well fluid to be pumped to the surface. It should be understood that while conventional wells are typically drilled vertically, conventional wells can also have some moderate curvature or deviation in the wellbore. 
     Horizontal wells may typically be drilled at an angle of roughly ten to twelve degrees over roughly 1000 feet to allow for a gradual slope. This results in approximately one degree of deviation for every 100 feet. A problem that occurs when drilling such wells, particularly when they are drilled relatively fast, is that the wells are not drilled perfectly, resulting in crooked wellbores. Such wells may have many slight to extreme deviations in the drill hole, which would create a non-linear configuration. When the deviated well is completed to depth, the drill pattern is positioned horizontally to drill. The pump, coupled to the sucker rod string, then must be lowered from the surface through all of the deviations of the wellbore down to the horizontal section of the well where it would be placed in service. 
     There are a number of problems that are regularly encountered during oil pumping operations. Oil that is pumped from the ground is generally impure, and includes water, gas, and solid impurities such as sand and other debris. The presence of solids can cause major damage to the pump components, thus reducing the run cycle of the pump, reducing revenue to the operator, and increasing expenses. For example, during pumping operations, scale, paraffin, or other solids buildup can accumulate in various areas of the tubing. This can create a very narrow tolerance between the pumping system&#39;s various subsurface components (including, for example, rods, rod couplings, and sinker bars) and the tubing which, in turn, can cause wear and damage to these subsurface components and tubing during pumping operations, especially when they are dragged across the interior diameter surface of the tubing. Further, particularly where deviations are present (whether in conventional or horizontal wells), the rod couplings can make contact with the tubing, also causing wear and damage to the couplings and tubing during pumping operations. In such situations, the rod couplings and tubing must then be repaired or replaced, which is both time consuming and expensive and, further, can result in loss of revenue to the well operators while the well is non-operational. 
     One solution to address these problems has been to provide wheeled couplings/rod guides. However, presently known wheeled couplings/rod guides suffer from several shortcomings in various areas of the design. For example, such wheeled couplings/rod guides are typically around 28 inches in length, which falls outside of the API specification range for rod couplings. Such wheeled couplings/rod guides require manual installation with hand wrenches or other hand tools. This method of installation is time consuming and can result in inconsistent torque application during coupling installation. This can cause loosening of the couplings and rod parts during pumping operations, leading to coupling failure and expensive well downtime. As a further example, the wheels of presently known wheeled couplings/rod guides are typically fitted through openings in the body of the coupling/rod guide and centered vertically in the body, such that portions of each wheel protrude from opposing sides of the body. This configuration can be problematic. For example, in the event that the wheel encounters a high spot in the tubing due to scale or paraffin or other solids buildup, the wheel will seize and drag through the high spot, causing damage to the wheel by flattening its protruding portions. 
     The present invention addresses these problems encountered in prior art pumping systems, and provides other, related, advantages. 
     SUMMARY 
     In accordance with one embodiment of the present invention, a roller coupling apparatus is disclosed. The roller coupling apparatus comprises, in combination: a body having a threaded north end and a threaded south end; and a plurality of wheels rotatably coupled to the body; wherein the wheels are positioned radially around the body; and wherein the wheels are spaced-apart equidistantly from each other. 
     In accordance with another embodiment of the present invention, a roller coupling apparatus is disclosed. The roller coupling apparatus comprises, in combination: a body comprising: a threaded north end; a threaded south end; a plurality of wheel wells positioned between the north end and the south end; and a plurality of aligned pairs of openings; a plurality of wheels rotatably coupled to the body; a plurality of inserts, each insert having an opening configured to receive an axle, and wherein each insert is configured to be positioned in an opening in one of the plurality of wheels; a plurality of axles, wherein each axle is configured to be positioned through one of the plurality of aligned pairs of openings in the body and in one of the plurality of inserts; wherein each wheel well of the plurality of wheel wells is configured to receive one of the plurality of wheels; wherein the wheels are positioned radially around the body; and wherein the wheels are spaced-apart equidistantly from each other. 
     In accordance with another embodiment of the present invention, a method for protecting pumping system components from wear during pumping operations is disclosed. The method comprises the steps of: providing a pumping unit; providing a roller coupling apparatus comprising, in combination: a body having a threaded north end and a threaded south end; and a plurality of wheels rotatably coupled to the body; wherein the wheels are positioned radially around the body; and wherein the wheels are spaced-apart equidistantly from each other; providing a first threaded component; providing a second threaded component; securing together the first and second threaded components by threadably coupling the north end of the roller coupling apparatus to a south end of the first threaded component and threadably coupling the south end of the roller coupling apparatus to a north end of the second threaded component to form an assembly; positioning the assembly within tubing of a wellbore; causing the assembly to move up with an upstroke of the pumping unit and down with a downstroke of the pumping unit; and during the movement with the upstroke and the downstroke, causing the wheels of the roller coupling apparatus to contact and roll along an interior diameter surface of the tubing. 
     In accordance with another embodiment of the present invention, a roller coupling apparatus is disclosed. The roller coupling apparatus comprises, in combination: a body having a threaded upper end, a threaded lower end, and a plurality of alternating curved outer surfaces and flat outer surfaces; and a plurality of wheels rotatably coupled to the body; wherein the wheels are positioned radially around the body; and wherein the wheels are spaced-apart equidistantly from each other. 
     In accordance with another embodiment of the present invention, a roller coupling apparatus is disclosed. The roller coupling apparatus comprises, in combination: a body comprising: a threaded upper end; a threaded lower end; a plurality of alternating curved outer surfaces and flat outer surfaces; a first plurality of partial circumferential grooves positioned proximate the upper end and a second plurality of partial circumferential grooves positioned proximate the lower end; a plurality of wheel wells positioned between the upper end and the lower end; and a plurality of aligned pairs of openings; a plurality of wheels rotatably coupled to the body; a plurality of inserts, each insert having an opening configured to receive an axle, and wherein each insert is configured to be positioned in an opening in one of the plurality of wheels; a plurality of axles, wherein each axle is configured to be positioned through one of the plurality of aligned pairs of openings in the body and in one of the plurality of inserts; wherein each wheel well of the plurality of wheel wells is configured to receive one of the plurality of wheels; wherein the wheels are positioned radially around the body; and wherein the wheels are spaced-apart equidistantly from each other. 
     In accordance with another embodiment of the present invention, a method for protecting pumping system components from wear during pumping operations is disclosed. The method comprises the steps of: providing a pumping unit; providing a roller coupling apparatus comprising, in combination: a body having a threaded upper end, a threaded lower end, and a plurality of alternating curved outer surfaces and flat outer surfaces; and a plurality of wheels rotatably coupled to the body; wherein the wheels are positioned radially around the body; and wherein the wheels are spaced-apart equidistantly from each other; providing a first threaded component; providing a second threaded component; securing together the first and second threaded components by threadably coupling the upper end of the roller coupling apparatus to a lower end of the first threaded component and threadably coupling the lower end of the roller coupling apparatus to an upper end of the second threaded component to form an assembly; positioning the assembly within tubing of a wellbore; causing the assembly to move up with an upstroke of the pumping unit and down with a downstroke of the pumping unit; and during the movement with the upstroke and the downstroke, causing the wheels of the roller coupling apparatus to contact and roll along an interior diameter surface of the tubing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present application is further detailed with respect to the following drawings. These figures are not intended to limit the scope of the present application, but rather, illustrate certain attributes thereof. 
         FIG. 1  is a side view of an embodiment of a roller coupling apparatus in accordance with one or more aspects of the present invention, with portions thereof shown in phantom; 
         FIG. 2  is a side, cross-sectional view of the roller coupling apparatus of  FIG. 1 , with portions thereof shown in phantom; 
         FIG. 3  is a bottom perspective view of the roller coupling apparatus of  FIG. 1 , with portions thereof shown in phantom; 
         FIG. 4  is an end view of the roller coupling apparatus of  FIG. 1 , with portions thereof shown in phantom; 
         FIG. 5A  is a perspective view of an illustrative wheel of the roller coupling apparatus of the present invention; 
         FIG. 5B  is a perspective view of an illustrative wheel of the roller coupling apparatus of the present invention; 
         FIG. 6  is a perspective view of an illustrative insert of the roller coupling apparatus of the present invention; 
         FIG. 7  is a perspective view of an illustrative axle of the roller coupling apparatus of the present invention; 
         FIG. 8  is a side view of an embodiment of a roller coupling apparatus in accordance with one or more aspects of the present invention; 
         FIG. 9  is a side view of another embodiment of a roller coupling apparatus in accordance with one or more aspects of the present invention; and 
         FIG. 10  is another side view of the roller coupling apparatus of  FIG. 9 ; 
         FIG. 11  is an end perspective view of an embodiment of a roller coupling apparatus in accordance with one or more aspects of the present invention; 
         FIG. 12  is a side view of the roller coupling apparatus of  FIGS. 11 ; and 
         FIG. 13  is an end view of the roller coupling apparatus of  FIG. 11  shown positioned in tubing. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The description set forth below in connection with the appended drawings is intended as a description of presently preferred embodiments of the disclosure and is not intended to represent the only forms in which the present disclosure may be constructed and/or utilized. The drawing figures are not necessarily drawn to scale and certain figures can be shown in exaggerated or generalized form in the interest of clarity and conciseness. The description sets forth the functions and the sequence of steps for constructing and operating the disclosure in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and sequences may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of this disclosure. 
       FIGS. 1-13 , together, disclose embodiments of a roller coupling apparatus  10  of the present invention. The roller coupling apparatus  10  is adapted to be used with a pumping system, such as an oil pumping system, that is positioned within a pump barrel. The roller coupling apparatus  10  is configured to securely couple two various threaded components that are placed within the tubing, such as rods, including sucker rods and pony rods, and sinker bars. The roller coupling apparatus  10  provides rolling capability at the threaded connections and thereby prevents subsurface components such as couplings, rods, and sinker bars from being dragged across the interior diameter surface of the tubing during pumping operations, which would cause damage to both the subsurface components and tubing. Although the term “oil” is used herein, it should be understood that the roller coupling apparatus  10  of the present invention may be used in pumping systems that pump fluids other than oil, such as debris-containing water. In describing the structure of the roller coupling apparatus  10  and its operation, the terms “north” and “south” are utilized. The term “north” is intended to refer to that end of the pumping system that is more proximate the pumping unit, while the term “south” refers to that end of the system that is more distal the pumping unit, or “downhole.” 
     Referring first to  FIGS. 1-3 , an embodiment of the roller coupling apparatus  10  of the present invention is shown. The roller coupling apparatus  10 , which has a substantially cylindrical external configuration, can be divided into the following principal components: a body  12  and a plurality of rollers or wheels  30  (hereinafter wheels  30 ) which are rotatably coupled to the body  12 . 
     Beginning at the top portion of  FIGS. 1-3 , the components of the roller coupling apparatus  10  will be described in further detail. In this embodiment, the body  12  comprises a north end  14  having an inlet  16 , which is configured to receive a southern end of a rod (not shown). Inlet  16  includes a threaded region  18 . Threaded region  18  is configured to permit the roller coupling apparatus  10  to be coupled to a southern end of a rod. As seen in this embodiment, threaded region  18  can originate southward of north end  14  and terminate northward of a plurality of wheel wells  20 . While in this embodiment threaded region  18  is shown as comprising female threading, in order to correspond to male pin threading present on the ends of conventional rods, it should be understood that threaded region  18  may comprise either male or female threading, as long as it engages corresponding male or female threading present on the rod to which it may be coupled. 
     Continuing southward in the drawing figures, as seen in this embodiment, the body  12  further includes a plurality of wheel wells  20 , each of which is configured to house one of a plurality of wheels  30 , as described further herein. Each wheel well  20  can be substantially semi-circularly shaped and can comprise a concave wall configured to correspond to the shape of each wheel  30 . With this configuration, a portion of each wheel  30  can be positioned within each wheel well  20 . This configuration helps to protect the wheels  30  from damage that could otherwise be caused by the narrow tolerance between the roller coupling apparatus  10  exterior and tubing interior due to buildup of scale, paraffin or other solids, since the wheels  30  will continue to roll in such solids buildup areas. This is in contrast to presently known wheeled couplings/rod guides, in that the wheels of such couplings/rod guides can seize and become dragged through areas of the tubing having solids buildup, flattening the wheels. Each wheel well  20  can have an overall diameter that is greater than an exterior diameter of each wheel  30 . In this way, each wheel  30  can be suspended when positioned in each wheel well  20  without contacting the interior surface of the wheel well  20 . As best seen in  FIG. 4 , in this embodiment, the roller coupling apparatus  10  utilizes a set of three wheel wells  20  (corresponding to three wheels  30 ) that are positioned in the same horizontal plane. The wheel wells  20  are positioned radially around the body  12  and are spaced-apart equidistantly from each other. In this embodiment, the wheel wells  20  are spaced  120  degrees apart. While in this embodiment three wheel wells  20  are shown, it should be understood that more than three wheel wells  20  (corresponding to more than three wheels  30 ) may be provided as may be needed for particular well conditions and configurations and depending upon the dimensions of the body  12  of the roller coupling apparatus  10 . 
     Referring now to  FIG. 4 , the body  12  further includes a plurality of aligned pairs of openings  28 . Each opening  28  is configured to receive an end of an axle  50 , to permit the wheels  30  to be coupled to the body  12 , as described further herein. While in this embodiment three aligned pairs of openings  28  (corresponding to three wheels  30 ) are shown, it should be understood that more than three aligned pairs of openings  28  (corresponding to more than three wheels  30 ) may be provided as may be needed for particular well conditions and configurations and depending upon the dimensions of the body  12  of the roller coupling apparatus  10 . 
     Referring again to  FIGS. 1-3  and continuing with the bottom portion thereof, in this embodiment, the body  12  further comprises a south end  22  having an inlet  24 , which is configured to receive a northern end of a rod (not shown). Similar to inlet  16 , inlet  24  includes a threaded region  26 . Threaded region  26  is configured to permit the roller coupling apparatus  10  to be coupled to a northern end of a rod or sinker bar. As seen in this embodiment, threaded region  26  can originate northward of south end  22  and terminate southward of wheel wells  20 . While in this embodiment threaded region  26  is shown as comprising female threading, in order to correspond to male pin threading present on the ends of conventional rods and sinker bars, it should be understood that threaded region  26  may comprise either male or female threading, as long as it engages corresponding male or female threading present on the rod or sinker bar to which it may be coupled. 
     In one embodiment, the body  12  can be approximately five inches in length. However, it should be understood that the length of the body  12  may deviate from this dimension, as desired. For example, the roller coupling apparatus  10  could have a length longer than five inches, in order to accommodate additional sets of three wheels  30  each, as described further herein, or as may be required for heavier rod loads, severe deviation of the wellbore configuration, and the like. As another example, the roller coupling apparatus  10  could have a length slightly less than five inches. 
     Referring now to  FIGS. 1-5A , the wheel  30  of the roller coupling apparatus  10  will be discussed in further detail. As seen in this embodiment, wheel  30  includes an outer wall  32  flanked by sidewalls  34 . Outer wall  32  can be substantially convex in shape. As best seen in  FIG. 5A , each wheel  30  is provided with a central opening  36 , defined by opening wall  38 , which is configured to receive an insert  40 . Wheel  30  can be fabricated from a variety of high-density materials suitable for downhole pumping applications including, by way of example only, various metals, such as stainless steel or alloys such as TOUGHMET alloys by Materion Corporation or high-density thermoplastics or high-density polymers. While in this embodiment three wheels  30  are provided in the roller coupling apparatus  10  (see  FIG. 4 ), it should be understood that more than three wheels  30  may be provided as may be needed for particular well conditions and configurations and depending upon the dimensions of the body  12  of the roller coupling apparatus  10 . 
     Referring now to  FIGS. 5B and 8 , in one embodiment, wheel  30  includes wear grooves  35 . In one embodiment, wear grooves  35  can be concentric and spaced apart equidistantly from each other. In one embodiment, each groove  35  can have a depth ranging from approximately 0.0001 to 0.010 inch. However, it would be possible to vary the depth of grooves  35 , as may be needed for particular well conditions and configurations. While in this embodiment seven grooves  35  are provided (with three grooves  35  on each sidewall  34  and one groove  35  on outer wall  32 ), it should be understood that more or fewer than seven grooves  35  may be provided as desired. 
     Referring now to  FIG. 6 , the insert  40  of the roller coupling apparatus  10  will be discussed in further detail. As seen in this embodiment, insert  40  is generally a hollow cylinder in shape. Insert  40  includes a central opening  42  defined by opening wall  44 , which is configured to receive an axle  50 . Insert  40  can include side surfaces  46  and outer surface  48 . Insert  40  can be fabricated from a variety of high-density materials suitable for downhole pumping applications including, by way of example only, various metals, such as stainless steel or alloys such as TOUGHMET alloys. While in this embodiment three inserts  40  are provided in the roller coupling apparatus  10  corresponding to three wheels  30  (see  FIG. 4 ), it should be understood that more than three inserts  40  may be provided depending upon the number of wheels  30  utilized. 
     Each wheel  30  is rotatably coupled to the body  12  by axle  50 , which is inserted through aligned openings  28  and  42  in the body  12  and insert  40 , respectively. Referring now to  FIG. 7 , the axle  50  of the roller coupling apparatus  10  will be discussed in further detail, As seen in this embodiment, axle  50  is generally cylindrical in shape. In one embodiment, axle  50  can be hollow and can include a slit  51  from end to end. When wheel  30  fitted with insert  40  is positioned in wheel well  20 , axle  50  may then be positioned through a first opening  28  in body  12 , opening  42  in insert  40 , and a second opening  28  in body  12 . When so positioned, each end of axle  50  may protrude outwardly from insert  40  into aligned pairs of openings  28  in the body  12 , thereby securing each wheel  30  in position on the body  12 . As seen in  FIG. 4 , in one embodiment, the ends of each axle  50  may further protrude slightly from an outer diameter of the body  12 . Referring to  FIG. 2 , each axle  50  can further include a plurality of ridges  52 , which may grip the opening wall  44  of insert  40 , thereby securing axle  50  in place. Ridges  52  can be longitudinal, running along a length of the axle  50 . Axle  50  can be fabricated from a variety of high-density materials suitable for downhole pumping applications including, by way of example only, various metals, such as stainless steel, carbon steel, or alloys such as TOUGHMET alloys. While in this embodiment three axles  50  are provided in the roller coupling apparatus  10  (see  FIG. 4 ), it should be understood that more than three axles  50  may be provided depending upon the number of wheels  30  utilized. 
     As best seen in  FIG. 4 , in this embodiment, the roller coupling apparatus  10  utilizes a set of three wheels  30  that are positioned in the same horizontal plane. The wheels  30  are positioned radially around the body  12  and are spaced-apart equidistantly from each other. In this embodiment, the wheels  30  are spaced 120 degrees apart. This configuration spreads the rod load more uniformly within the interior diameter of the tubing. In this regard, this configuration allows for 360-degree load weight carrying of the rod to transfer to the wheels  30  which roll inside the tubing, thereby eliminating the surface-to-surface wear of the sucker rod coupling and tubing that can occur during pumping operations, especially in deviated areas of the wellbore. While in this embodiment three wheels  30  are provided in the roller coupling apparatus  10 , it should be understood that more than three wheels  30  may be provided as may be needed for particular well conditions and configurations and depending upon the dimensions of the body  12  of the roller coupling apparatus  10 . For example, where the body  12  has relatively larger dimensions, it may be desired to provide additional radially-positioned wheels  30 . Further, while in this embodiment the wheels  30  are shown positioned inline vertically on the body  12 , it should be understood that the wheels  30  can be positioned at various degrees from vertical on the body  12 . Such a configuration allows for slight rod rotation during pumping operations which, in turn, allows for more even wear, helping to eliminate premature pumping operation failures related to rod and tubing wear issues. 
     Referring now to  FIGS. 9-10 , reference number  100  refers generally to another embodiment of the roller coupling apparatus of the present invention. The roller coupling apparatus  100  is similar to the roller coupling apparatus  10 , but includes a body  12  of a length longer than the roller coupling apparatus  10  in order to accommodate an additional set of wheels  30 . For this reason, the same reference numbers used in describing the features of the roller coupling apparatus  10  will be used when describing the identical features of the roller coupling apparatus  100 . 
     In this embodiment, the body  12  includes six wheel wells  20 , corresponding to six wheels  30  (see  FIGS. 9-10 , which show opposing sides of the roller coupling apparatus  100 ). However, it should be understood that more or less than six wheel wells  20 , corresponding to more or less than six wheels  30 , may be provided as desired. As can be seen from a review of  FIGS. 9-10 , a first set of three wheel wells  20  is provided proximate the north end  14  of the body  12 , while a second set of three wheel wells  20  is provided proximate the south end  22  of the body  12 . In one embodiment, the body  12  of the roller coupling apparatus  100  can be approximately seven inches in length. This longer length, compared to the length of the roller coupling apparatus  10  (which, as described above, is approximately five inches in length), is configured to accommodate the second set of three wheel wells  20  and wheels  30 . However, it should be understood that the length of the body  12  may deviate from this dimension, as desired. For example, the roller coupling apparatus  100  could have a length longer than twenty-four inches, in order to accommodate yet additional sets of wheels  30 . It should be noted that for each additional set of wheels incorporated into the roller coupling apparatus  100 , approximately two inches are added to the length of the body  12  in order to accommodate the additional wheel set(s). For example, a roller coupling apparatus  100  with three sets of wheels would have a body  12  length of approximately nine inches, a roller coupling apparatus  100  with four sets of wheels would have a body  12  length of approximately eleven inches, and so on. 
     As seen from a review of  FIGS. 9-10 , in this embodiment, the roller coupling apparatus  100  utilizes two sets of three wheels  30  each, including three wheels  30  positioned in a northern wheel region  54 , proximate the northern end  14  of the body  12 , and three wheels  30  positioned in a southern wheel region  56 , proximate the southern end  22  of the body  12 , for a total of six wheels  30 . The wheels  30  of the northern wheel region  54  are positioned in a first horizontal plane. Further, the wheels  30  of the northern wheel region  54  are positioned radially around the body  12  and are spaced-apart equidistantly from each other. In this embodiment, the wheels  30  of the northern wheel region  54  are spaced 120 degrees apart. Similarly, the wheels  30  of the southern wheel region  56  are positioned in a second horizontal plane that is located southward of the first horizontal plane. Further, the wheels  30  of the southern wheel region  56  are positioned radially around the body  12  and are spaced-apart equidistantly from each other. In this embodiment, the wheels  30  of the southern wheel region  56  are spaced 120 degrees apart. As seen from a review of  FIGS. 9-10 , the wheels  30  of the northern wheel region  54  are staggered relative to the wheels  30  of the southern wheel region  56 , and vice versa, such that each wheel  30  of the northern wheel region  54  is positioned diagonally from each wheel  30  of the southern wheel region  56 , and vice versa. As with the roller coupling apparatus  10 , the configuration of the wheels  30  in the roller coupling apparatus  100  spreads the rod load more uniformly within the interior diameter of the tubing. In this regard, this configuration allows for 360-degree load weight carrying of the rod to transfer to the wheels  30  which roll inside the tubing, thereby eliminating the surface-to-surface wear of the sucker rod coupling and tubing that can occur during pumping operations, especially in deviated areas of the wellbore. As with the roller coupling apparatus  10 , while in this embodiment the wheels  30  are shown positioned inline vertically on the body  12 , it should be understood that the wheels  30  can be positioned at various degrees from vertical on the body  12 . Such a configuration allows for slight rod rotation during pumping operations which, in turn, allows for more even wear, helping to eliminate premature pumping operation failures related to rod and tubing wear issues. 
     While non-grooved wheels  30  are shown in the embodiment in  FIGS. 9-10 , it should be understood that the wheels  30  of the roller coupling apparatus  100  may include wear grooves  35 , as shown in  FIG. 5B  and as discussed above. 
     Referring now to  FIGS. 11-13 , reference number  200  refers generally to another embodiment of the roller coupling apparatus of the present invention. The roller coupling apparatus  200  is similar to the roller coupling apparatus  10 , but includes a plurality of flat outer surfaces  62  and a plurality of grooves  64 . For this reason, the same reference numbers used in describing the features of the roller coupling apparatus  10  will be used when describing the identical features of the roller coupling apparatus  200 . 
     In this embodiment, the body  12  includes a plurality of alternating outer surfaces, including a plurality of curved outer surfaces  60  and a plurality of flat outer surfaces  62 . Each surface  60  is longitudinal, running along a length of the body  12 , and is juxtaposed between a pair of flat outer surfaces  62 . Similarly, each surface  62  is longitudinal, running along a length of the body  12 , and is juxtaposed between a pair of curved outer surfaces  60 . Each surface  62  is also positioned between a pair of wheels  30 . As can be seen from a review of  FIGS. 11-12 , a portion of each surface  62  proximate the north end  14  and south end  22  of the body  12  may generally be substantially T-shaped. In this way, surface  62  can accommodate end portions of a plurality of grooves  64 , as described further herein. While in this embodiment three surfaces  62  are shown, it should be understood that more than three surfaces  62  may be provided as may be needed for particular well conditions and configurations and depending upon the dimensions of the body  12 . 
     This configuration of the roller coupling apparatus  200 , with its flat outer surfaces  62 , can provide one or more advantages. In this regard, as the roller coupling apparatus  10 ,  100 , or  200  is deployed, over time, the wheels  30  will become worn. Depending upon the amount of wear undergone by the wheels  30 , it is possible that various regions of the outer surface of the body  12  could come into contact with the interior surface of the tubing. The roller coupling apparatus  200 , with its flat outer surfaces  62 , eliminates this concern. As can be seen from a review of  FIG. 13 , for example, the flat outer surfaces  62  allow for more space between the outer diameter of the roller coupling apparatus  200  and the interior diameter of the tubing  300  proximate the flat outer surfaces  62 , as compared to the curved outer surfaces  60 , which allow for relatively less space between the outer diameter of the roller coupling apparatus  200  and the interior diameter of the tubing  300  proximate the curved outer surfaces  60 . Further, with its combination of alternating curved outer surfaces  60  and flat outer surfaces  62 , the outer diameter of the roller coupling apparatus  200  proximate outer surfaces  60  can be configured according to standard coupling outer diameter dimensions, while the outer diameter of the roller coupling apparatus  200  proximate outer surfaces  62  can be configured according to API slim hole specifications, as understood by those of skill in the art. Overall, this configuration allows for greater fluid flow capacity around the roller coupling apparatus  200 , particularly in the areas proximate flat surfaces  62 , compared to rolling coupling apparatus  10  and  100 , as well as compared to presently known wheeled couplings/rod guides, thereby providing improved efficiency during pumping operations. 
     Referring now to  FIGS. 11-12 , in this embodiment, the body  12  further includes a plurality of partial circumferential grooves  64  formed in an outer surface of the body  12 . Each groove  64  can be positioned along a portion of one of the curved outer surfaces  60  of the body  12  and can be juxtaposed between a pair of flat outer surfaces  62 . Opposing end portions of each of the grooves  64  may each terminate at one of the plurality of flat surfaces  62 , defining substantially T-shaped regions of the body  12  proximate the north end  14  and south end  22 , as noted above. The grooves  64  are configured to permit a tool to be coupled to the roller coupling apparatus  200  so that retrieval of the roller coupling apparatus  200  and/or rods from the wellbore may be accomplished, as further described herein. In this embodiment, three grooves  64  are positioned proximate the north end  14  of the body  12 , while three grooves  64  are positioned proximate the south end  22  of the body  12 , for a total of six grooves  64 . While in this embodiment six grooves  64  are shown, it should be understood that more than six grooves  64  may be provided as may be needed for particular well conditions and configurations and depending upon the dimensions of the body  12 . 
     As described herein, each roller coupling apparatus  10 ,  100 , and  200  is configured to be coupled at its north end  14  to the south end of a rod, and at its south end  22  to the north end of another rod or to a sinker bar, thereby connecting the two rods together, or connecting a rod and a sinker bar together, to form an assembly. Multiple roller coupling apparatuses  10 ,  100 , and  200  may be utilized to connect multiple rods together, thereby forming a rod string of various lengths, as may be needed depending on the depth of the well and length of the wellbore in which the roller coupling apparatuses  10 ,  100 , and  200  are employed. 
     The roller coupling apparatus  10  or  200  can be installed in the same manner as a conventional rod coupling. In this regard, the roller coupling apparatus  10  or  200  can be installed with hydraulic power tongs on the pulling unit. Such tongs can be set so that an equal amount of torque is applied to each roller coupling apparatus  10  or  200  utilized in a given pumping operation, which can include multiple roller coupling apparatuses  10  or  200  as may be needed. This method of installation is economical, efficient, and provides torque consistency among the rod couplings. Compared to manual installation, this method of installation is faster in that it can require a few seconds to install rod couplings with hydraulic power tongs, as opposed to the minutes that may be required for manual installation. 
     Unlike the roller coupling apparatus  10  or  200 , the roller coupling apparatus  100 , with its multiple sets of wheels  30 , is not suited for installation with hydraulic power tongs on the pulling unit, due to its longer body length. Instead, the roller coupling apparatus  100  can be installed manually with hand wrenches or other hand tools. 
     In operation, the roller coupling apparatus  10 ,  100 , or  200 , being part of the rod string, will move up with the upstroke of the pumping unit and down with the downstroke of the pumping unit. As the roller coupling apparatus  10 ,  100 , or  200  moves within in the wellbore, wheels  30  make contact with and roll along the interior diameter surface of the tubing. This prevents the body  12  exterior from contacting the tubing interior, preventing surface-to-surface wear of the body  12  exterior and tubing interior, including in deviated areas of the wellbore. In turn, with the wheels  30  contacting the tubing, this helps to keep the rods from contacting the tubing. This prolongs the life of the rod assembly and tubing. 
     Further, with respect to the roller coupling apparatus  200  with its flat outer surfaces  62 , more space is provided between the outer diameter of the roller coupling apparatus  200  and the interior diameter of the tubing  300 , as compared to the regions proximate curved outer surfaces  60 , as discussed above. This, too, prevents the body  12  exterior from contacting the tubing interior, preventing surface-to-surface wear of the body  12  exterior and tubing interior, including in deviated areas of the wellbore, thereby prolonging the life of the rod assembly and tubing. 
     The roller coupling apparatus  10 ,  100 , or  200  that includes one or more wear grooves  35  on wheels  30  provides further advantages. In this regard, wear grooves  35  allow the operator to determine the wear undergone by the wheels  30  and provide an indication of when the roller coupling apparatus(es)  10 ,  100 , or  200  should be repaired or replaced. The operator can inspect the wheels  30  for wear along the sidewalls  34 , outer walls  32 , or both when the well experiences down-time and the downhole pumping system components are retrieved for repair. This will enable the operator to determine the location of the most severe wear areas in the wellbore, by reviewing the wear patterns on the wheels  30  including where the grooves  35  have become worn. The operator can then make an informed decision, based on quantitative data, to place additional roller coupling apparatuses  10 ,  100 , or  200  in the severe wear areas, by replacing single sucker rods with multiple, shorter, pony rods, which would allow for more roller coupling apparatuses  10 ,  100 , or  200  to be installed in wellbore locations experiencing severe wear. Such wear may occur due to such reasons as rod loading in deviated areas of the wellbore or rod buckling due to fluid pounding caused by the pump barrel not completely filling with fluid in between pump strokes. This causes the rods to buckle in the tubing, particularly when the traveling valve passes through an empty space in the barrel and then slams into the fluid area. This results in a large shock throughout the rod assembly, causing damage to the rods and tubing. Utilizing the roller coupling apparatus  10 ,  100 , or  200  in the rod assembly lessens the damage to the rod assembly and tubing. 
     The roller coupling apparatus  200 , with its plurality of grooves  64  provides further advantages. In this regard, as noted above, the grooves  64  are configured to permit a tool to be coupled to the roller coupling apparatus  200  for retrieving the roller coupling apparatus  200  and/or rods from the wellbore. In this regard, in the event that the rods become detached from the roller coupling apparatus  200 , the operator can use a tool known as a fishing tool or overshot, which includes inward-facing spring barbs. Once the fishing tool/overshot is slid over the roller coupling apparatus  200 , the barbs can latch into the grooves  64 , allowing the operator to then retrieve the roller coupling apparatus  200  and rods from the wellbore. 
     The foregoing description is illustrative of particular embodiments of the invention, but is not meant to be a limitation upon the practice thereof. While embodiments of the disclosure have been described in terms of various specific embodiments, those skilled in the art will recognize that the embodiments of the disclosure may be practiced with modifications without departing from the spirit and scope of the invention.