MULTI-PIECE ROD GUIDE FOR WELLS
1. A guide for sucker rods comprising:
- a cylindrical profile having a first end, a second end, an outer surface, and an inner surface;
at least one internal groove along the inner surface; and
a plurality of protrusions extending from the outer surface, along the longitudinal axis of the cylindrical profile, wherein the plurality of protrusions terminate gradually to form a first plurality of bow shapes at the first end and a second plurality of bow shapes at the second end,wherein the sucker rod guide is formed from a plurality of semi-cylindrical pieces, wherein the plurality of semi-cylindrical pieces are interference fit to each other to form the cylindrical profile and the plurality of protrusions, and wherein adhesive applied to the at least one internal groove secures the plurality of pieces to the sucker rod.
A guide for sucker rods comprises a cylindrical shape including an orifice for the sucker rod and four protrusions extending outwardly therefrom. The guide utilizes a symmetrical two-piece design wherein each piece comprises a semi-cylindrical shape, with one full protrusion extending the length of the guide and two half protrusions extending half the length of the guide and also beyond the semi-cylindrical profile. These two pieces are attached to each other by means of an interference fit between two pairs of interlock surfaces, one pair of which is located on the inner surface of the portion of the half-protrusions extending beyond the semi-cylindrical profile, and the other pair of which is located on the outer surface of the guide on the opposite side from the two half protrusions. Epoxy is injected into grooves along the internal surface of the cylindrical shape by means of ports extending through the rod guide.
- 1. A guide for sucker rods comprising:
a cylindrical profile having a first end, a second end, an outer surface, and an inner surface; at least one internal groove along the inner surface; and a plurality of protrusions extending from the outer surface, along the longitudinal axis of the cylindrical profile, wherein the plurality of protrusions terminate gradually to form a first plurality of bow shapes at the first end and a second plurality of bow shapes at the second end, wherein the sucker rod guide is formed from a plurality of semi-cylindrical pieces, wherein the plurality of semi-cylindrical pieces are interference fit to each other to form the cylindrical profile and the plurality of protrusions, and wherein adhesive applied to the at least one internal groove secures the plurality of pieces to the sucker rod.
- View Dependent Claims (2, 3, 4, 5, 7, 8, 9, 10, 11, 12, 13)
- 6. A guide for sucker rods comprising two pieces disposed about a longitudinal axis and
defining an orifice therethrough, each of the two pieces comprising: a semi-cylindrical profile having a first end and a second end; an outer surface and an inner surface, the inner surface comprising at least one internal groove; a first protrusion extending from the outer surface and along the longitudinal axis of the semi-cylindrical piece, wherein the first protrusion terminates at the first end and the second end; a second and third protrusion extending from the outer surface and along the longitudinal axis, wherein the second and third protrusions each terminate at the first end and halfway between the first end and the second end, and wherein a portion of the second and third protrusions extends circumferentially beyond the semi-cylindrical profile; a first pair of interlock surfaces, wherein the first pair of interlock surfaces is located on either side of the first protrusion, near the second end of the piece; and a second pair of interlock surfaces, wherein the second pair of interlocking surfaces is located on the portion of the second and third protrusions extending beyond the semi-cylindrical profile; wherein the first pair of interlock surfaces of one of the two pieces forms an interference fit with the second pair of interlock surfaces of the other of the two pieces, wherein the second pair of interlock surfaces of one of the two pieces forms an interference fit with the first pair of interlock surfaces of the other of the two pieces, and wherein adhesive applied to the at least one internal groove secures the pieces to the rod.
- 14. A method of fitting a rod guide to a sucker rod, comprising:
molding a plurality of guide pieces having a semi-cylindrical profile and at least one interlock surface; transporting the plurality of guide pieces to an installation location having a sucker rod; applying an adhesive to an internal surface of the plurality of guide pieces; aligning the plurality of guide pieces with each other along the sucker rod; engaging the interlock surfaces of the plurality of guide pieces with each other; and applying force to the plurality of guide pieces such that the interlock surfaces deform each other to create an interference fit rod guide along the sucker rod.
- View Dependent Claims (15, 16, 17, 18, 19, 20)
Embodiments usable within the scope of the present disclosure relate, generally, to an interference fit guide for sucker rods utilizing a two-piece design which allows the guide to be molded to the rod.
When production from a hydrocarbon well attainable through natural means (e.g., pressure within the wellbore) is no longer sufficient for the well to remain economically viable, numerous types of secondary recovery methods exist to increase the productivity of the well. One such method includes use of a downhole pump that is inserted into the wellbore, then actuated to draw hydrocarbons and/or other fluids toward the surface. Conventionally, downhole pumps are actuated by physically manipulating values and/or other operable parts from the surface, through movement of a pump jack or similar powered device connected to the downhole pump using a long string of joined connectors, termed “sucker rods.”
When in use, these sucker rods are used in conjunction with sucker rod guides to prevent contact between sucker rods and production tubing. Depending on how straight or how vertical the individual wellbore is, these guides may be spaced on the rod depending on the engineering recommendations. Commonly, these rod guides are made using composite materials and thermoplastics including, e.g., polyphthalamide nylon, polyphenylene sulfide, and polyethylene.
The standard method of fitting a rod guide to a sucker rod involves direct-injection molding of the guide onto the rod body. This works reasonably well for instances where the sucker rod is steel, due to surface irregularities allowing the guide to hold in place. However, when the sucker rod is made of fiberglass, the smooth surface may allow the guide to slip when the sucker rod is under load. As a result, fiberglass sucker rods require an additional procedure in which the rod is sanded down at each guide location and a bead of epoxy is applied to the rod and allowed to harden into a “key” prior to the molding process to prevent slippage.
However, this process has drawbacks. Since the retention of the guide in place is directly related to the manual application of the epoxy, inconsistency in application can lead to wide variability in retention loading. In addition, the high heat (600° F.) of the direct-injection molding process may stress the fiberglass and cause damage. Finally, even a slight misalignment of the rod with the mold can subject the rod to clamping forces which damage it and require extensive inspection.
A need exists for a rod guide which can be used with both steel and fiberglass rods with reliability and consistency between applications.
Embodiments of the apparatus described herein meet this and other needs.
In the detailed description of the embodiments, presented below, reference is made to the accompanying drawings:
One or more embodiments are described below with reference to the listed Figures.
Before describing selected embodiments of the present disclosure in detail, it is to be understood that the present invention is not limited to the particular embodiments described herein. The disclosure and description herein is illustrative and explanatory of one or more presently preferred embodiments and variations thereof, and it will be appreciated by those skilled in the art that various changes in the design, organization, order of operation, means of operation, equipment structures and location, methodology, and use of mechanical equivalents may be made without departing from the spirit of the invention.
As well, it should be understood the drawings are intended to illustrate and plainly disclose presently preferred embodiments to one of skill in the art, but are not intended to be manufacturing level drawings or renditions of final products and may include simplified conceptual views as desired for easier and quicker understanding or explanation. As well, the relative size and arrangement of the components may differ from that shown and still operate within the spirit of the invention.
Moreover, it will be understood that various directions such as “upper,” “lower,” “bottom,” “top,” “left,” “right,” and so forth are made only with respect to explanation in conjunction with the drawings, and that the components may be oriented differently, for instance, during transportation and manufacturing as well as operation. Because many varying and different embodiments may be made within the scope of the concept(s) herein taught, and because many modifications may be made in the embodiments described herein, it is to be understood that the details herein are to be interpreted as illustrative and non-limiting.
The present invention relates, generally, to a rod guide which is molded separately from the sucker rod as a two-piece configuration, thereby preventing exposure of the sucker rod to the stressful high temperatures of the molding operation. The two pieces of the guide interlock in a wedge engagement that tightens onto the sucker rod using an interference fit, also known as a friction fit or force fit, under the application of axial force.
In an embodiment, the rod guide may feature internal pocket(s) molded to the guide to hold an epoxy adhesive which is applied to the guide during the interference fit. Unlike the prior art rod guides, this configuration relies on both the epoxy adhesive and the interference fit to provide load-bearing strength to the sucker rod against dislocation loads (i.e., loads tending to push the rod guide up or down along the sucker rod).
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In addition, each protrusion 20, 22, 24, 26 terminates along the longitudinal axis X in two tapered edges, one on each end of the rod guide 10. For brevity, only the tapered edges 30a, 30b corresponding to protrusion 20 are labeled in
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During assembly, the inner interlock profiles 40 on either side of guide half 16 form an interference fit with the outer interlock profiles 50 of guide half 18. In addition, guide half 16 also comprises outer interlock profiles (not shown) and guide half 18 also comprises inner interlock profiles (not shown) at the same positions; these are not visible in the overhead and underhead views, they are located in the same positions and function identically. Thus, each guide half 16, 18 comprises both a pair of inner interlock profiles located on the outer surface 14, as well as a pair of outer interlock profiles which are located on the half protrusions 24a/24b, 26a/26b.
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In the next step 202, epoxy adhesive is applied to the internal guide surfaces as described in
In a method embodiment, the ram force of the hydraulic press shoes is controlled 206 with a programmable pressure transducer which controls the compressing action such that the hydraulic press ceases applying pressure once a predetermined force has been achieved, after which the operator installing the rods may remove excess adhesive 207 and then repeat the procedure along the next guide position.
Although several preferred embodiments of the invention have been illustrated in the accompanying drawings and described in the foregoing specification, it will be understood by those of skill in the art that additional embodiments, modifications and alterations may be constructed from the invention principles disclosed herein, while still falling within the scope of the disclosed invention.