1. Technical Field
These inventions relate, generally, to apparatus and methods used in well servicing, such as oil and gas wells. More specifically, the inventions relate to downhole apparatus which when assembled in a tubing string can repeatedly and selectively create a fluid bypass in the circulating system of a well being serviced.
2. Background Art
As is known in the relevant art, bypass tools are typically run into wellbores assembled or connected in a tubular string and are utilized to selectively discharge fluids from the interior of the tubing string into the annular space around the tool. In some applications, this discharge is used to boost or assist the flow of debris in the annulus.
As used herein, the words “comprise,” “have,” “include,” and all grammatical variations thereof are each intended to have an open, non-limiting meaning that do not exclude additional elements or steps. The term “wellbore” refers to the subterranean well opening, including cased and uncased. The term “tubing string” is used generically to refer to tubular members positioned in a wellbore, such as drill pipe, tubing and the like. The term “well fluids” refers broadly to any fluids found in a wellbore. As used in this application, the term “bypass” refers to a fluid flow path from the bore or interior of a tubing string into the wellbore/tubing string annulus, at some point along the length of the tubing string, rather than out the lower most end of the tubing string and downhole assembly. It is understood that even in a bypass mode, some fluid may still traverse the length of the tubing string and exit the lowermost end thereof. As used herein, “weight down” is used to describe a condition of the tubing string where at least a portion of the weight of the tubing string is supported downhole in compression rather than tension. As used herein, the term “poppet valve” is used to refer to a valve operated by springs or the like that plugs and unplugs its openings by axial movement.
The present inventions provide a tool with a tubular body for assembly in a tubing string which can be selectively activated to provide bypass flow. The tool preferably includes a body with one or more ports or passageways connecting the interior of the tubing string with the annulus. The tool includes metallic, ball-shaped valves and metallic seats. The ball-shaped valves can be cycled or moved into and out of positions blocking or permitting bypass flow through the passageways even when the fluid are being pumped through the tool under pressure. In other words, it is not required to shut down fluid circulation when activating the tool. In addition, the tubing string can be rotated and axially cycled while the tool is in the bypass flow position.
The drawings are incorporated into and form a part of the specification to illustrate at least one embodiment and example of the present inventions. Together with the written description, the drawings serve to explain the principles of the inventions. The drawings are only for the purpose of illustrating at least one preferred example of at least one embodiment of the inventions and are not to be construed as limiting the inventions to only the illustrated and described example or examples. The various advantages and features of the various embodiments of the present inventions will be apparent from a consideration of the drawings in which:
Referring now to the drawings, wherein like reference characters refer to like or corresponding parts throughout the several figures, there is illustrated in
A central passageway or bore 22 extends the length of the bypass valve 10, as shown, and when assembled in a tubing string the passageway is in fluid communication with the interior of the string as indicated by arrows F. Main body 20 may be made in two body sections 20A and 20B, joined by a threaded connection 24. Two axially spaced sets of ports 26 extend through the wall of the upper body section 20A. In this embodiment, each set comprises a plurality of ports, in this example, four ports are circumferentially spaced at 90 degree intervals. Also, in this embodiment only two sets of ports are illustrated, however it should be understood that, depending on the valve diameter and bypass flow requirements, more or less sets could be present. As will be described, these ports 26, when open, provide bypass flow from the bore 22 of the bypass valve 10 to the annulus 14.
A generally cylindrical spool 40 is disposed within bore 22 of main body 20 for rotational and axial movement therein. The term “spool” is not intended to be limited to a particular shape. The spool 40 is located adjacent the ports 26.
Spool 40 is held within bore 22 by one or more index pins 25 mounted to extend through the wall of main body 20 so as to protrude into indexer slot 42. It is understood that spool 40 may move axially and rotate as the index pins 25 ride or are confined in the indexer slot 42. It is to be understood that the positions of the pin and slot could be reversed, with the slot formed on the interior of the body and the pin mounted on the body. Spool 40 further comprises a plurality of openings or ports 44 through the wall of the spool 40. As shown, the spool of the illustrated embodiment has two axially spaced sets of eight ports 44. These ports 44 are circumferentially spaced 45 degrees apart. The axial spacing of these sets of ports 44 correspond to the axial spacing of the sets of ports 26 in the upper section 26a. Balls 46, preferably of hard metal such as carbon chrome, are mounted in enlarged (counter-bored) alternate ports 44. When fluid pressure or flow is present inside the spool 40, the balls 46 move outwardly so as to seal the flow path through ports 44 and 26 These counterbores form pockets for loosely retaining the balls. Ports 44 are spaced and mounted to align with ports 26 in upper body section 20a. When spool 40 is in one position (with the index pins 25 resting in one notch configuration 43), balls 46 are aligned with ports 26, and when so aligned, balls 46 are moved outwardly by fluid pressure/flow so as to seal the ports 26 and prevent any fluid flow through ports 44 and 26. When spool 40 is in the adjacent position (with the pins 25 located in the adjacent notch configuration 43), namely rotated one “notch,” then open ports 44 (that is, without balls 46 therein) are aligned with ports 26, and the bypass is thereby open and fluid may flow from bore 22 into the annulus 14, thereby affecting the bypass. The method of moving the spool 40 from between the notch configurations 43 will be described hereinafter. It is understood that the alternate ports 44 and balls 46 could be eliminated, allowing the spool to act as a valve element.
The bypass valve 10 also comprises a mandrel 50 disposed within main body 20. As illustrated in the drawings, mandrel 50 comprises a longitudinal bore 52. A reduced or smaller diameter upper mandrel section 53 extends upwardly into bore 22 of main body 20 and is connected to the spool 40 at 49. A lower, larger diameter plunger section 54 is sized to fit snugly within a chamber 27 formed within the lower body section 20B of the main body 20. Preferably, external splines 55 engage internal splines 29 formed in chamber 27 of the lower body section 20A. The interaction or meshing of the splines serves to rotationally lock mandrel 50 in the main body 20 while permitting and telescoping movement. Plunger section 54 further comprises seals 56 to provide a fluid seal with the walls of chamber 27. The lower end of mandrel 50 preferably has a means for connecting the mandrel to a drill string, such as threaded connection 57. Mandrel 50 may also be provided with a second set of external splines 58, which serve as a mounting base for an enlarged diameter member such as a stabilizer or landing ring 100.
Bypass valve 10 further comprises a check valve system which controls fluid flow into and out of the chamber 27. As will be explained, the check valve system operates as a mechanical trigger which can be preset to prevent telescoping of the mandrel with the body unless a set telescoping force is applied.
In the illustrated embodiment, the poppet valves 70 and 72 comprise balls 77 and 78, respectively, which act as valve elements. So as to affect the fluid seal, springs 79 resiliently urge the balls 77 and 78 against seats 80 and 82, respectively. Springs or other biasing elements can be selected, as desired, to control the pressure required to open the valves for fluid entry/exit. The springs are selected to apply sufficient force to the balls to prevent friction or drag on the tubing string and landing ring 100 during insertion in the well from causing poppet valve 72 to opening. On the other hand, the springs are selected so that poppet valve 72 will open and discharge fluid from chamber 27 when the string is in the weight down condition.
For example, with bypass valve 10 in the closed position (
Other structural features of bypass valve 10 and how the various parts interact with one another can be described by a description of the operation or function of bypass valve 10 by reference to
Prior to the tool being run into the wellbore, spool 40 is rotated such that balls 46 are aligned with ports 26 in main body 20. In this position, fluid flow through the ports is blocked, and the tool is therefore “closed.” As illustrated, mandrel 50 is in a lowermost position with respect to main body 20. In this position plunger section 54 is at the bottom of chamber 27. As bypass valve 10 is lowered into the wellbore, wellbore fluid is in chamber 27. It is understood that poppet valve 70 can be spring biased to open at a desired pressure to equalize the pressure in chamber 27 and the annulus 14. Fluid in chamber 27 cannot flow from chamber 27 until the telescoping force on the valve and pressure in chamber 27 overcomes the opening pressure/force for poppet valve 72 (which is spring biased to open at a desired pressure). As the string containing the tool is inserted into the well, drag forces on the tool string below the bypass valve 10 may cause the plunger 54 to compress the well fluid in chamber 27; however, by selecting a spring 79 with sufficient bias on the ball 72 to prevent fluid discharge, inadvertent activation of the tool can be avoided. It is understood that mandrel 50 can move longitudinally with respect to main body 20, within structural limits, but mandrel 50 and main body 20 are always rotationally locked by virtue of splines 55 and 28. This feature permits rotating the drill string below bypass valve 10 in either closed or bypass position.
In order to open the bypass valve 10 when down hole, it is necessary to move main body 20 with respect to the mandrel 50, which in turn causes the spool 40 to rotate with respect to upper body section 20A. This movement is created by placing the bypass valve 10 in a weight down position as illustrated in
It can be appreciated that telescoping movement between the mandrel 50 and the main body 20 causes plunger section 54 to pump the fluid in chamber 27 out of chamber 27 through poppet valve 72. As previously mentioned, poppet valve 72 can be preset so as to control the amount of force which must be imposed on mandrel 50 to cause fluid to flow through poppet valve 72. This aspect of bypass valve 10 permits the user to control how much weight must be set down before poppet valve 72 will permit fluid to flow from chamber 27, and thereby permit mandrel 50 to move into main body 20. As previously pointed out, setting the poppet valve 72 to a sufficient level prevents inadvertent activation of the valve during insertion and axial movement in the well.
As mentioned above, after mandrel 50 has been moved upwardly, by setting weight down on bypass valve 10, the drill string must be raised so as to move the main body 20 upward with respect to the mandrel 50, thereby moving spool 40 downwardly so as to align open ports 44 (namely, without balls 46 therein) and 26, and forming the fluid bypass flow path. As can be seen in
The bypass valve can be cycled between open and closed positions as many times as desired, by setting weight down on the tool and then picking up. This endless cycling of the valve is accomplished by making the indexer seat 42 endless. In this embodiment, the indexer slot extends continuously circumferentially around the spool 40. It is envisioned that configurations of continuous indexer slots are known in the industry and would enable endless cycling of the valve. Balls 46 in spool 40 are preferably made of carbon chrome steel, and thereby form a metal-to-metal seal in ports 26, enabling the tool cycling to be done under flow conditions, e.g. while fluid bypass is occurring, without cutting out of the hard metal balls or seats. This is in distinction to prior art bypass valves which used resilient seal elements, such as 0-rings, which are highly likely to be cut and destroyed by fluid flow thereby. Replaceable, removable annular seats (see
Several novel aspects flow from the structure and operation of the tool. Once the tool has been placed into either the bypass open or closed positions, reciprocation of the drill string and tool can be resumed; this is in contrast to known prior art downhole bypass valves which (once the bypass has been opened) require that the tool be kept in compression to maintain the bypass open, thereby preventing reciprocation of the drill string. As described above in the operational sequence, the bypass can be cycled an unlimited number of times, yielding a repeatable bypass activation system. This repeatable aspect is of key importance should the bypass mechanism be prematurely opened, for example from encountering a downhole obstruction while tripping in the hole, shifting the tool because of high down hole fluid friction forces, etc. The present inventions are capable of handling high pressures, as the metal-to-metal seal in the bypass is not readily deformed or destroyed by high pressures. Finally, the structure of the tool lends it to use with any type of fluid in the wellbore, from solids laden mud to clear brines.
As is well known in the relevant art, high strength metals and metal alloys may be used to fabricate many of the parts of the bypass valve. Seal elements (such as 0-rings or other resilient seals) are provided as necessary to create fluid/pressure seals between components.
While the preceding description contains many specificities, it is to be understood that same are presented only to describe some of the presently preferred embodiments of the inventions, and not by way of limitation. Changes can be made to various aspects of the inventions, without departing from the scope thereof. For example, dimensions and materials can be changed to suit particular situations; the tool can be run in conjunction with other downhole tools; etc. Therefore, the scope of the inventions is not to be limited to the illustrative examples set forth above, but encompasses modifications which may become apparent to those of ordinary skill in the relevant art.
Therefore, the present inventions are well adapted to carry out the objects and attain the ends and advantages mentioned as well as those which are inherent therein. While the inventions have been depicted, described, and are defined by reference to exemplary embodiments of the inventions, such a reference does not imply a limitation on the inventions, and no such limitation is to be inferred. The inventions are capable of considerable modification, alteration, and equivalents in form and function, as will occur to those ordinarily skilled in the pertinent arts and having the benefit of this disclosure. The depicted and described embodiments of the inventions are exemplary only, and are not exhaustive of the scope of the inventions. Consequently, the inventions are intended to be limited only by the spirit and scope of the appended claims, giving full cognizance to equivalents in all respects.
Also, the terms in the claims have their plain, ordinary meaning unless otherwise explicitly and clearly defined by the patentee. Moreover, the indefinite articles “a” or “an”, as used in the claims, are defined herein to mean one or more than one of the element that it introduces. If there is any conflict in the usages of a word or term in this specification and one or more patent(s) or other documents that may be incorporated herein by reference, the definitions that are consistent with this specification should be adopted.
This application claims priority from U.S. Provisional Patent Application No. 61/233,646 filed Aug. 13, 2009 entitled “REPEATABLE, COMPRESSION SET DOWNHOLE BYPASS VALVE,” which is hereby incorporated by reference in its entirety.
Number | Date | Country | |
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61233646 | Aug 2009 | US |