CENTER ROD PLUNGER
Described herein are embodiments of systems, apparatuses, and methods that include a center rod plunger, wherein movement and/or placement of the center rod is at least partially controlled by the center rod including a centering section that keeps the center rod more centered in the center rod plunger's housing. The center rod plunger may also include a clutch for retarding movement of the center rod in the housing. In still other embodiments, the center rod may have a shaft whose diameter may vary and a clutch that may include a one-piece device.
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This application is a continuation in part of and claims priority to patent application Ser. No. 18/464,112 filed on Sep. 8, 2023, which claims priority to provisional patent application Ser. No. 63/410,686 filed Sep. 28, 2022, each of which is fully incorporated herein by reference.
TECHNICAL FIELD OF THE INVENTIONEmbodiments of the subject matter disclosed herein relate to an improved center rod plunger, and methods of operating and using the same.
DISCUSSION OF THE BACKGROUNDIt is well known that production from oil and gas wells can suffer due to the build-up of fluids at the bottom of the well. Various methods and devices have been developed to remove those fluids so as to improve the well's productivity. The present invention assists in that process.
SUMMARYThe following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an exhaustive overview of the invention. It is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is later discussed.
Described herein are embodiments of systems and apparatuses that include a center rod plunger wherein movement and/or placement of the center rod is at least partially controlled by the center rod including a centering section that keeps the center rod more centered in the center rod plunger's housing. Other embodiments include a clutch for retarding movement of the center rod in the housing. In still other embodiments, the center rod has a shaft whose diameter may vary and a clutch that may include a one-piece device, as described in more detail below in the detailed description of the invention.
The disclosure may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements, and in which:
Various features and advantageous details are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known starting materials, processing techniques, components, and equipment are omitted so as not to unnecessarily obscure the invention. It should be understood, however, that the detailed description and the specific examples, while indicating embodiments of the invention, are given by way of illustration only, and not by way of limitation. Various substitutions, modifications, additions, and/or rearrangements within the spirit and/or scope of the underlying inventive concept will become apparent to those skilled in the art from this disclosure.
The words and phrases used herein should be understood and interpreted to have a meaning consistent with the understanding of those words and phrases by those skilled in the relevant art. No special definition of a term or phrase, i.e., a definition that is different from the ordinary and customary meaning as understood by those skilled in the art, is intended or implied. To the extent that a term or phrase is intended to have a special meaning, i.e., a meaning other than that understood by skilled artisans, such a special definition will be expressly set forth in the specification in a definitional manner that directly and unequivocally provides the special definition for the term or phrase.
The present embodiments describe an improved center rod plunger. Those skilled in the art will appreciate the purpose, function, and operation of a center rod plunger. Essentially, a center rod plunger is a device for removing fluids from a well. The plunger is released into the top of a well, were it then travels/falls down the well. When it strikes the bottom (or a stopper) of the well, the plunger's center rod is forced into its “closed” position, such that fluid and gases are substantially prohibited from passing through the interior of the plunger. When the pressure below the plunger is sufficiently greater than the pressure above the plunger, the plunger begins to rise/ascend (or travel up) toward the top of the well. This upward travel, in combination with the fact that gases and fluids are substantially prevented from traveling through the interior of the plunger, causes the plunger to push such liquids toward the top of the well, where they are eventually removed from the well.
When the plunger reaches the top of the well, typically a rod or other device in the wellhead's lubricator forces the plunger's center rod back into its “open” position, where liquids and gases are allowed to flow through the interior of the plunger. Other mechanisms may be used to dislodge the center rod from its closed position, including gravity, i.e., where the center rod is weighted in proportions such that it is capable (under the correct operational/environmental circumstances) of opening on its own. Where the plunger is not otherwise held or maintained in the lubricator, this causes the plunger to once again fall down the well, where the process/cycle is repeated. In this fashion, liquids can be removed from the well, thereby enabling the well to flow more freely, to the economic benefit of its producer.
Details of the present invention will be appreciated by those skilled in the art by reference to the attached and described drawings. While the drawings collectively seek to illustrate aspects of the invention, the invention is not limited to the details of the drawings themselves.
As indicated, when center rod plunger assembly 25 is in its closed position as shown in
As the embodiments of
The relative increase in diameter of center rod 27 between regions 33a and 33b is sufficient to enable clutch 31 to retard movement of center rod 27 between is opened and closed positions. Stated otherwise, the region of increased diameter between regions 33a and 33b is sized so that center rod 27 is biased to remain in either its open or closed position, but also able to move between the two positions when center rod plunger assembly 25 hits the bottom of the well (thereby driving center rod 27 from its open to its closed position) or the top of the well (thereby driving center rod 27 from its closed to its open position). In other words, the force exerted on center rod 27 by hitting either the top or bottom of the well is greater than the frictional force exerted on center rod 27 by clutch 31 when the clutch is positioned on the center rod between regions 33a and 33b. In this manner, center rod plunger assembly 25 is designed to generally remain in its closed position as it is ascending in the well, and to generally remain in its open position when it is descending in the well. One perceived advantage of this shaft/clutch design is that it reduces tension and/or wear on the clutch when compared to a shaft of constant diameter since the center rod only transitions between its open and closed positions a fraction of the time that it is in use.
All of this said, in another embodiment, center rod 27 could have a constant outside diameter (at least in the region of travel of clutch 31) such that there is no material difference in the diameter of the rod (relative to its interaction with clutch 31) when it is positioned in its open position, its closed position, or there-between, noting however that the outside diameter is at least sufficient to retard movement of the center rod while the assembly is traveling in the well bore, but not so much as to prevent it from moving between its open/closed position when it reaches the bottom/top of the well.
Finally,
This embodiment of clutch 130 also includes undulating inside surface/diameter 132. In other embodiments, the inside surface/diameter 132 is not undulating. The purpose of undulating inside surface/diameter 132 is at least so the entire inside surface/diameter of clutch 130 does not contact center rod 27.
Finally, as best illustrated by
Further elaborating on the disclosed characteristics of the exemplary center rod 27 of
As indicated above, center rod 27 can have at least a first region of reduced diameter and optionally additional regions of reduced diameter relative to other regions of the center rod. For example, a first region of reduced diameter 33a could relate to the assembly's open position and a second region of reduced diameter 33b could relate to the assembly's closed position. In an embodiment, the length of this second region of reduced diameter is greater than the height of the clutch by an amount desired by the designer as discussed further below. Applicants have designed the difference to be approximately ⅛ inch, but other measurements (larger or smaller) are possible depending on the amount of relative “play” (or relatively free movement) of the center rod between what is described below as the center rod's minimum closed position and the center rod's maximum closed position.
One reason for the differential in length between the length of the second region of reduced diameter and the height of the clutch is because it is desired that the center rod move more freely in this region. As described above, the center rod will move more freely in this region because the reduced diameter of the center rod correspondingly reduces the amount of friction between the center rod and the clutch. As such, the center rod will move more freely between a maximum closed position (i.e., when the center rod is in sealing contact with the bore of the plunger) and a minimum closed position (i.e., when the center rod is not in complete sealing contact with the bore of the plunger). The distance between the maximum closed position and the minimum closed position is substantially the same as the difference between the length of the center rod's second region of reduced diameter and the height of the clutch.
In operation, as described above, the plunger will travel up the wellbore when its center rod is in its maximum closed position and the pressure below the plunger is sufficiently greater than the pressure above the plunger. As the plunger travels up the wellbore, it may experience pressure changes due to pockets of gas, liquid, or other reasons that will be understood by those skilled in the art. In the event the pressure change is such that the pressure below the plunger is not sufficiently greater than the pressure above the plunger to drive the plunger toward the surface, the plunger may stall and/or begin to fall back down the wellbore. In this scenario, due to the differential in length between the length of the second region of reduced diameter and the height of the clutch, the center rod is able to move from its maximum closed position to its minimum closed position, thereby allowing the flow of the well to flush the plunger's clutch mechanism and bore of sand or other debris deleterious to the operation and longevity of the plunger.
When the pressure again changes such that the pressure below the plunger is sufficiently greater than the pressure above the plunger, such pressure differential will cause the plunger's center rod to move from its minimum closed position to its maximum closed position. As such, closure of the center rod is not entirely dependent on the plunger striking a bottom stop in the well, but rather movement of the center rod—between its maximum closed position and its minimum closed position—can be controlled by well conditions when the clutch is positioned in this area of reduced rod diameter. Those skilled in the art will appreciate that these pressure changes (that cause the plunger's center rod to move between is minimum and maximum closed positions) can be various and can occur rapidly, such that the path of the plunger to the surface is not always steady or constant. It has been observed and it is believed, however, that the ability of the center rod to move between is minimum and maximum closed positions at least results in more consistent plunger runs than those without it.
Other embodiments that allow the center rod to similarly move between its minimum and maximum closed positions also are possible and within the scope of the present invention. For example, the center rod can freely move between its maximum closed position and its minimum closed position where the height of clutch receptacle 30 is larger than the height of clutch 31. In other words, by sizing the height of clutch receptacle 30 to be larger than the height of clutch 31, the plunger can accomplish the same function of having its center rod move between a maximum and minimum closed position in the same manner as described above by including on the center rod a region of reduced diameter greater in length than the height of the clutch.
The embodiments could also be combined such that the distance between the maximum closed position and the minimum closed position is a function of both (1) the difference between the height of the clutch receptacle and the height of the clutch; and (2) the difference between the length of an area of reduced diameter of the center rod and the height of the clutch. In any of the embodiments, the various clutches disclosed herein could be used, i.e., the clutch disclosed in
In the particular embodiment shown in
Although the invention(s) is/are described herein with reference to specific embodiments, various modifications and changes can be made without departing from the scope of the present invention(s), as set forth in the claims below. Accordingly, the specification and Figures are to be regarded in an illustrative rather than a restrictive sense, and all such modifications are intended to be included within the scope of the present invention(s). Any benefits, advantages, or solutions to problems that are described herein with regard to specific embodiments are not intended to be construed as a critical, required, or essential feature or element of any or all the claims.
Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements. The terms “coupled” or “operably coupled” are defined as connected, although not necessarily directly, and not necessarily mechanically. The terms “a” and “an” are defined as one or more unless stated otherwise. The terms “comprise” (and any form of comprise, such as “comprises” and “comprising”), “have” (and any form of have, such as “has” and “having”), “include” (and any form of include, such as “includes” and “including”) and “contain” (and any form of contain, such as “contains” and “containing”) are open-ended linking verbs. As a result, a system, device, or apparatus that “comprises,” “has,” “includes” or “contains” one or more elements possesses those one or more elements but is not limited to possessing only those one or more elements. Similarly, a method or process that “comprises,” “has,” “includes” or “contains” one or more operations possesses those one or more operations but is not limited to possessing only those one or more operations.
Accordingly, the protection sought herein is as set forth in the claims below.
Claims
1. A center rod plunger assembly for removing liquids in a well, said assembly comprising:
- a body have a bore there-through;
- a center rod mounted in the bore to move between an open position and a closed position, where flow from the well travels through at least a portion of the bore in the open position, and flow from the well does not travel through at least a portion of the bore in the closed position;
- the center rod including a centering section that interacts with the bore to assist in maintaining the center rod in a more centered position in the bore; and
- a clutch mounted in the bore;
- wherein said clutch interfaces with the center rod to retard movement of the center rod between its open position and its closed position by exerting a frictional force on the center rod.
2. The center rod plunger of claim 1 wherein the center rod includes a first region of reduced diameter.
3. The center rod plunger of claim 2 wherein the clutch exerts less frictional force on the center rod when the clutch interfaces with the center rod's first region of reduced diameter.
4. The center rod plunger of claim 3 wherein the center rod is in its open position when the clutch interfaces with the center rod's first region of reduced diameter.
5. The center rod plunger of claim 4 wherein the center rod includes a second region of reduced diameter.
6. The center rod plunger of claim 5 wherein the clutch exerts less frictional force on the center rod when the clutch interfaces with the center rod's second region of reduced diameter.
7. The center rod plunger of claim 6 wherein the center rod is in its closed position when the clutch interfaces with the center rod's second region of reduced diameter.
8. The center rod plunger of claim 7 wherein the body includes a first end and a second end, and wherein the first end includes a ramped surface for mounting the clutch in a clutch receptacle.
9. The center rod plunger of claim 8 wherein the bore has a first inside diameter and the clutch receptacle has a second inside diameter, where the second inside diameter is greater than the first inside diameter.
10. The center rod plunger of claim 9 wherein the clutch is a one-piece unit.
11. The center rod plunger of claim 9 wherein the clutch is a one-piece unit having an outside diameter and an inside diameter, where the inside diameter of the clutch is sized to create a frictional interface with the center rod, and wherein the clutch includes a spiral cut in at least a portion of its outside diameter.
12. The center rod plunger of claim 9 wherein the clutch is a one-piece unit having at least one inside diameter sized to create a frictional interface with the center rod and at least one slot so that the entire inside diameter of the clutch does not impart a frictional force on the center rod.
13. The center rod plunger of claim 9 wherein the clutch is a one-piece unit having height, an outside diameter, and an inside diameter, where the inside diameter is sized to create a frictional interface with the center rod, and wherein the clutch further includes a gap extending from its outside diameter to its inside diameter along its entire height.
Type: Application
Filed: Nov 30, 2023
Publication Date: Mar 28, 2024
Applicant: Epic Lift Systems (Houston, TX)
Inventors: Robert G. Roycroft (Houston, TX), Shannon S. Freeman (Tomball, TX)
Application Number: 18/525,227