NO20141188A1 - Tool with segmented multi-size seat - Google Patents

Abstract

A wellbore tool including a housing with an axial flow bore and a piston sleeve movably disposed within the flow bore. The tool is movable between first and second operating positions by an actuating mechanism having a plunger with a seat having a plurality of separate arcuate segments. The tool can be moved between first and second operating positions by using actuator plugs of different sizes that can be landed on the seat.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of US Application No. 13/469852, filed

11 May 2012, which is hereby incorporated by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Scope of the invention

[0002] The invention generally relates to circulation valves and sliding sleeve tools. In particular aspects, the invention relates to the design of plug seats used in actuation mechanisms for such tools.

2. Description of Related Art

[0003] Well drilling tools have been constructed that are operated by the use of a ball or plug that lands on a seat within the flow bore of the tool string. The ball or plug serves to increase pressure and/or redirect fluid flow through the tool to operate the tool. Tools of this type include circulation valves that are used to selectively open and close lateral fluid flow ports in a tool passage to allow fluid to flow axially through the tool to be diverted into the surrounding flow bore. Circulation valves of this type are described in US Patent No. 4889199, issued to Lee, US Patent No. 5499687, issued to Lee, US Patent No. 7281584, issued to McGarin et al. and US Patent No. 7416029, issued to Telfer et al.

[0004] The parent application thereof describes tools which operate using balls or plugs and which have a plug capture and release mechanism which includes a C-ring type seat. The parent application for this is US patent application no. 12/860985, filed August 23, 2010, which is incorporated by reference in its entirety.

SUMMARY OF THE INVENTION

[0005] The invention provides plug capture and release mechanisms that include plug seats with rings of unconnected segments that are radially expandable within different chamber portions of an expansion chamber to allow balls or plugs of different sizes to pass through the seat. The configuration of the seat allows the ball seat to be reused. In the described embodiments, the seat is built up of a plurality of separate arc-shaped holding segments which collectively form an annular seat exhibiting an upper seat surface.

[0006] In some embodiments, the seat provides a degree of flow through the seat when the ball or plug is disposed on the seat. In one described embodiment, at least some neighboring segments of the seat have different dimensioned inner diameters in relation to other segments. When a plug is provided on the seat, the plug is provided on the segment exhibiting a smaller internal diameter. A quantity of fluid can flow past the seat through the spaces provided between the plug and the segments having larger internal diameters. This element allows fluid at a low flow rate to pass through the seat even after a plug has initially landed on the seat. As a result, the circulation valve or other tool within which the seat is used will not move to the open or closed position prematurely. In the described embodiments, a follower device and spring are used to stabilize the seat segments.

[0007] In another described embodiment, the retaining segments of the seat are formed at the distal (remote) ends of a plurality of clamping sleeves extending axially from a foundation ring. The use of collets and a foundation ring provides stability and prevents the segments of the seat from rotating which could result in them being misplaced from their positions.

[0008] Plug seats constructed according to the present invention can expand radially outward to form a surrounding enclosure. During operation, a plug is arranged on the seat, and fluid pressure can build up against the plug and the seat. When the seat is moved into an enclosure with a smaller inner radius, the seat is expanded radially. The holding segments are spread apart so that the openings between them become larger. Conversely, when the seat is moved into an enclosure with a smaller inner radius, the seat contracts radially. A compression spring applies an axial load to push the seat towards this contracted position. The holding segments have been moved closer together so that the openings between them shrink. In special embodiments, the seat is used within an expansion chamber with at least three chamber parts of different internal diameters. The seat is capable, by design, of expanding to conform within each of these three or more chamber portions. As a result, the seat is able to selectively capture and release plugs of different sizes.

[0009] Exemplary circulation valves are described which include seats constructed in accordance with the present invention. The exemplary circulation valves include a substantially cylindrical housing with a central axial flow bore and a piston sleeve movably located within the flow bore. The tool includes an outer housing that forms an axial flow bore. External lateral flow ports are fitted through the housing. The housing holds a piston sleeve with internal lateral flow ports, and movement of the piston sleeve within the housing will bring the inner flow ports into and out of alignment with the outer flow ports.

[0010] In the described embodiments, an indexing mechanism is used to control the axial position of the piston sleeve within the housing. This indexing mechanism allows the tool to alternate back and forth between a first operating position in which the outer lateral flow ports are closed off for fluid flow, and a second operating position in which the outer lateral flow ports are opened for fluid flow. In one described embodiment, the indexing mechanism includes an indexing sleeve with a cam track inscribed thereon. Cams are carried by the housing and are positioned within the cam track to move between different positions within the track as the piston sleeve is moved axially. The axial position of the piston sleeve is controlled by the location of the cams within the cam track.

[0011] The tool also shows an actuation mechanism which allows the tool to be switched between its first and second operating positions by means of release balls or other plugs which are landed on the seat within the piston sleeve. Increased fluid pressure is used to move the piston sleeve axially downwards against a biasing force, such as a spring. Downward movement of the piston sleeve moves the seat into an expansion chamber portion of increased diameter. The increased diameter allows the seat to release an actuation plug. The tool requires one size of actuation plug to move the tool from a first operating position to a second operating position and a second size of actuation plug to move the tool from the second operating position back to the first operating position.

[0012] During the process of dropping plugs through the bore of the tool, a positive feedback indication may be provided to a surface operator via the resulting fluid pressure in the tool string thereby confirming the operation of the tool.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The advantages and further aspects of the invention will be easily understood by those normally skilled in the field after this is better understood by reference to the following detailed description when viewed in connection with the accompanying drawings in which equal reference numbers indicate equal or similar elements out through the many figures in the drawings and in which:

[0014] Figure 1 is a side, cross-sectional view of an exemplary circulation valve tool incorporating a seat constructed in accordance with the present invention, and the circulation valve tool in a first operational position.

[0015] Figure 1A is an enlarged cross-sectional view of portions of the seat of the tool shown

in fig. 1.

[0016] Figure 2 is a side, cross-sectional view of the tool shown in FIG. 1, now in a first intermediate position.

[0017] Figure 3 is a side, cross-sectional view of the tool shown in fig. 1-2, now in a second operating position.

[0018] Figure 4 is a side, cross-sectional view of the tool shown in FIG. 1-3, now in a second intermediate position.

[0019] Figure 5 is an enlarged side cross-sectional view of portions of the tool shown in FIG. 4, now in a first operating position.

[0020] Figure 6 is an enlarged side cross-sectional view of the tool portions shown in FIG. 5, now in the first intermediate position.

[0021] Figure 7 is an enlarged side cross-sectional view of the tool portions shown in FIG. 5 and 6, now in the second operating position.

[0022] Figure 8 is an enlarged side cross-sectional view of the tool portions shown in FIG. 5-7, now in the second intermediate position.

[0023] Figure 9 is a side view of an exemplary seat constructed in accordance with the present invention, apart from other components of the circulation transition tool and in a fully retracted position.

[0024] Figure 10 is a top view of the seat shown in fig. 9.

[0025] Figure 11 is a cross-sectional view taken along lines 11-11 in fig. 10.

[0026] Figure 12 is an external isometric view of the seat shown in fig. 9-11.

[0025] Figure 13 is an isometric view of an alternative seat constructed in accordance with the present invention.

[0026] Figure 14 is another isometric view of the seat shown in fig. 13.

[0027] Figure 15 is a side cross-sectional view of portions of an exemplary alternative circulation valve tool incorporating the seat of FIG. 13 and 14.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0028] Figures 1, 1A and 2-8 illustrate an exemplary circulation valve tool 10 constructed in accordance with the present invention. The upper part of the tool 10 is shown on the left side in fig. 1 and 2-4, the lower part of the tool 10 being shown in the right side of fig. 1 and 2-4. The circulation valve tool 10 includes a generally cylindrical outer housing 12 showing an upper axial end 14 and a lower axial end 16. The upper end 14 includes a box-type threaded connection 18, and the lower end 16 provides a bolt-type threaded connection 20. The connections 18, 20 are of a type known in the art for incorporating the tool 10 in a tool string (not shown) placed in a wellbore. The housing 12 forms a central flow bore 22 along its length. In a preferred embodiment, the housing 12 is made up of an upper transition 24 and a lower transition 26 which are threaded together at connection 28. Outer lateral fluid ports 30 are placed through the housing 12.

[0029] Located within the housing 12, and preferably within the lower end of the upper transition 24, is a stepped expansion chamber, generally shown at 32. Figures 1A show a chamber 32 in greater detail. As best seen there, expansion chamber 32 includes three chamber portions 32a, 32b and 32c having internal diameters that increase sequentially. The small diameter portion 32a has the smallest diameter. The large diameter chamber portion 32c has the largest diameter. The intermediate diameter chamber portion 32b has a diameter larger than the small diameter chamber portion 32a, but is smaller than that of the large diameter chamber portion 32c.

[0030] An indexing chamber 34 is formed within the housing 12 below the expansion chamber 32. One or more indexing lugs 36 are provided through the housing and protrude into the indexing chamber 34. Although a single lug 36 is visible in fig. 5-8, it is currently preferred that there are several lugs 36 which are angularly separated around the circumference of the housing 12.

[0031] Below the indexing chamber 34, a damping chamber 38 is formed within the housing 12. Lateral filling ports 40 are placed through the housing 12 and closed off with plugs 42.

[0032] A piston sleeve 44 is placed within expansion chamber 32. The piston sleeve 44 has a generally cylindrical body 46 which forms a central flow path 47. A flange 48 projects radially outward from the body 46 and has internal radial fluid ports 50 placed therein. Annular fluid seals 51 surround the body 46 and seal against the surrounding housing 12, thereby isolating the fluid ports 50.

[0033] A plug seat 52 is located inside the flow bore 22 and placed on the piston sleeve 44. An exemplary seat 52 is shown in greater detail in FIG. 9-12. The seat 52 is constructed of a plurality of separate arcuate holding segments 53 and 54. Segments 54 have a larger internal diameter than segments 53. In the described embodiment, segments 53 and 54 are arranged in an alternating manner so that each segment 53 is adjacent to a segment 54 on one side or the other and vice versa.

[0034] The seat 52 can be created by first obtaining two annular main rings, one of which has a larger internal diameter than the other ring. The main ring with the larger internal diameter would provide the segments 54 with the other main ring providing the segments 53. The main rings are each cut into segments arranged with segments from the other main ring to form two seats 52 according to the present invention.

[0035] In the embodiment shown, an O-ring holder 55 is located within a groove 57 which is inscribed within the outer radial surface of the segments 53, 54. The O-ring holder 55 is useful for holding the segments 53, 54 on space together during handling and assembly of the tool 10. The outer radial surface of the seat 52 is dimensioned to fit within the small diameter chamber portion 32a when the segments 53, 54 are in adjacent contact with each other.

[0036] Segments 53 each present an upper, inward-facing primary seating surface such that seat 52 is capable of capturing both small plug 84 and a larger plug 86. As can be seen with reference to FIG. 10, 11 and 12, however, the plug is not provided on the segments 54, being provided on the seat 52. As a result, an opening 59 is shown between the plug 84 and each segment 54.

[0037] In the described embodiment, a flange support sleeve 61 is attached to the upper end of the piston sleeve 44. As can best be seen in fig. 1 A, there is preferably a follower sleeve 63 located above the seat 52. A compression spring 65 biases the follower sleeve 63 downward on the seat 52, and this biasing force helps to hold the separate segments 53, 54 of the seat 52 in place against the flange support sleeve 61 through operation .

[0038] A central opening is formed centrically within the seat 52. Figures 9-12 show the seat 52 in a fully retracted position in which the central opening is the smallest since the adjacent segments 53, 54 are in contact with each other. Figures 2 and 4 show the seat 52 in expanded configurations in which the central opening is larger due to the segments 53, 54 being spread apart.

[0039] The design of the seat 52 allows balls or other plugs of different sizes to be caught and released. It should be noted that the plugs 84 and 86 shown in the drawings are spherical balls. Arrows or plugs with other shapes or configurations can also be used. When the seat 52 is located within the smaller diameter chamber portion 32a, the seat 52 is in the fully retracted position and both a smaller actuation plug 84 and a larger actuation plug 86 can be arranged on the seat 52. When the seat 52 is located within the intermediate diameter chamber portion

32b (see Fig. 3), the seat 52 will be in a partially extended position, since the segments 53, 54 are separated from each other within the constraints of the intermediate diameter chamber portion 32b. As a result, a larger actuation plug 86 will still be captured by the seat 52. However, when the seat 52 is positioned within the intermediate diameter chamber portion 32b, the smaller actuation plug 84 will pass through the central opening of the seat 52. When the seat 52 is located within the larger diameter chamber portion 32c, the seat 52 will be in a further extended position and both the smaller plug 84 and the larger plug 86 will pass through the central opening of the seat 52.

[0040] An indexing sleeve 56 surrounds a lower portion of the body 46 within the indexing chamber 34 and is movable within the indexing chamber 34. The indexing sleeve 56 is generally cylindrical and has a radially expanded skirt portion 58. An annular spring chamber 60 is formed radially between the skirt portion 58 and the body 46 to piston sleeve 44. The upper end of the indexing sleeve 56 has an inwardly extending flange 62 which occupies the body 46. A compression spring 64 surrounds the piston sleeve 44 and is arranged generally within the spring chamber 60. The upper end of the compression spring 64 abuts the flange 62 while the lower end of the spring 64 abuts an annular plug portion 66 which is placed within the indexing chamber 34 and seals off the indexing chamber 34 from the damping chamber 38. It should be noted that an annular fluid seal 67 forms a seal between the lower transition 26 and the piston sleeve 44. Fluid seals 69 are located around and within the plug part 66 to ensure sealing against the piston sleeve 44 and indexing breastfeeding 34.

[0041] As can be seen with reference to fig. 5-8, the indexing sleeve 56 exhibits an outer radial surface 68 having a cam track 70 inscribed therein. The cam track 70 is shaped and sized to hold the inner ends of each of the cams 36 therein. The cam track 70 generally includes a central circumferential track 72. A plurality of legs extend axially away from the central track 72. The track 70 is constructed such that the number of each type of leg is equal to the number of cams 36 used with the track 70. Long legs 74 and short legs 76 extend axially downward from the central track 72. In addition, long legs 78 and short legs 80 extend axially upwards from the central track 72.

[0042] With reference again to fig. 1-4, it should be noted that a damping piston 82 is preferably located within the damping chamber 38. The damping piston 82 is securely attached to the piston sleeve 44 and contains one or more restriction fluid flow nozzles 83 that extend completely around the damping piston 82. Fluid seal 85 radially surrounds the damping piston 82 and forms a fluid seal against the inner wall of damping chamber 38. A hydraulic fluid fills damping chamber 38 both above and below the damping piston 82.

[0043] The tool 10 can be repeatedly moved between a first operating position, in which the outer fluid ports 30 are closed against fluid flow, and a second operating position, in which the outer fluid ports 30 are open to fluid flow. To do this, actuation plugs 84 and 86 are let into the flow bore 22 of the tool 10 to cause the tool 10 to be actuated between these positions. Plug 84 is of a smaller size than plug 86. When the tool 10 is initially built up into a tool string and driven into a wellbore, it is typically in the first operating position shown in fig. 1, even if plug 84 is not present. The seat 52 is located within the small diameter chamber portion 32a of the expansion chamber 32. The cams 32 are located within the long downwardly extending legs 74 (see Fig. 5). In this position, fluid flow through the lateral fluid ports 30 is shut off at the indexing sleeve 56. The inner fluid flow ports 50 are also not aligned with the outer fluid flow ports 30 and fluid seals 51 prevent fluid communication with the inner ports 50. Fluid can flow and tools can be passed axially through the flow bore 22 to the tool 10.

[0044] Due to the configuration of the seat 52, an operator may land a plug on the seat 52 and continue to operate another tool below the circulation valve tool 10 until the tool 10 is subsequently actuated. The smaller plug 84 is dropped into the flow bore 22 where it lands on the seat 52 (see Figs. 1 and 1 A). Fluid pressure can then be increased within flow bore 22 above the landed plug 84. Due to the presence of the openings 52 between the plug 84 and the segments 54 of the seat 52, fluid can flow through the seat 52 even after the plug 84 has been landed. Fluid flow through the valve tool 10 can be used to operate a tool that is below the tool 10 in the tool string. The total flow area for the tool 10 through the openings 59 should be less than the total flow area under the tool 10 or to any tool under the tool 10 to be operated after landing the plug 84 or 86. It should be noted that the total flow area of the tool 10 in this case can be changed by replacing the segments 54 and replacing them with segments that have either a larger or smaller internal diameter. As a result, the size of the openings 59 will be changed and thus the total flow area provided by the tool 10.

[0045] This flow-through element to the seat 52 also allows an operator to safely start his rig pumps without immediate actuation of the tool 10 in the event that a plug 84 or 86 has been inadvertently placed in the wellbore. The amount of pump flow can then be gradually increased to achieve the necessary fluid pressure to actuate the tool 10 in a manner that will be described hereafter.

[0046] When it is desired to open the lateral fluid ports 30 to allow fluid communication between the flow bore 22 and the surrounding wellbore, a further increased fluid pressure causes the piston sleeve 44 and attached indexing sleeve 56 to move axially downward with respect to the housing 12, as shown in Fig. . 2. The compression spring 64 is compressed. The cams 34 will move along the path 70 to be located within the upwardly extending legs 80 of the path 70 (see Fig. 6). As this axial movement occurs, indexing sleeve 56 and piston housing 44 are rotated within housing 12.

[0047] As the piston sleeve 44 moves axially downward to the first intermediate position shown in fig. 2 and 6, the seat 42 is moved into the intermediate diameter chamber portion 32b of the expansion chamber 32. The expanded diameter of the intermediate diameter chamber portion 32b allows the segments 53, 54 of the seat 52 to expand away from each other and release the small plug 84, as shown . The cams 36 will push out into the short, upwardly extending legs 80 of the cam track 70 when the seat 52 is in position to release the plug 84. The released plug 84 may be captured by a ball catch (not shown) of a type known in the art, which is located within the tool string under tool 10.

[0048] After the plug 84 has been released from the seat 52, the spring 64 will push the piston sleeve 44 and indexing sleeve 56 axially upward within the housing 12. Upward movement of the piston sleeve 44 and indexing sleeve 56 will stop when the cams 36 push out in the short downward extending pin 76 to cam track 70. The tool

10 will now be in the second operating position shown in fig. 3 and 7. In this operating position, the inner fluid flow ports 50 of the piston sleeve 44 are aligned with the outer fluid flow ports 30 of the housing 12 so that fluid can flow between the inner flow bore 22 and the surrounding wellbore. It should also be noted that the seat 52 is now once again located radially within the small diameter chamber portion 32a of the expansion chamber 32. [0049] When it is desired to return the tool 10 to the first (closed) operating position shown in fig. 1 and 5, the larger plug 86 is dropped into the flow bore 22 and lands on the seat 52. Fluid pressure is then increased within the flow bore 22 above the plug 86. The increased fluid pressure will push the piston sleeve 44 and the indexing sleeve 56 axially downward within the housing 12 and compress the spring 64. The tool 10 is now in the second intermediate position shown in fig. 4. The cams 36 have been moved into the upwardly extending long legs 78 of the cam track 70 (see fig. 8). As a result, the seat 52 is moved downward into the large diameter portion 32c of the expansion chamber 32, thereby allowing the central opening of the seat 52 to expand sufficiently to allow the larger plug 86 to be released from the seat 52.

[0050] As the larger plug 86 is released from the seat 52, the spring 64 will push the piston sleeve 44 and the indexing sleeve 56 axially upward even more and return the tool to the first operating position illustrated in FIG. 1 and 5. From this first operating position it can once again be moved to the second operating position (fig. 3 and 7) and back again by repeating the steps described above. It should be noted that the tool 10 can be repetitively moved between the driven and other operating positions by the sequential use of a smaller plug 84 followed by a larger plug 86. Those skilled in the art will appreciate that, because the cam path 70 surrounds the indexing sleeve 56 in a continuous manner, the steps described above can be repeated to cycle the tool 10 between operating positions.

[0051] Only a smaller plug 84 would be useful for moving the tool 10 from the first (closed) operating position to the second (open) operating position. If a large plug 86 were landed on the seat 52 when the tool 10 is in the first operating position (Figs. 1 and 5), the large plug 86 would not be released from the seat 52 when the seat 52 is moved downwardly into the intermediate diameter chamber portion 32b ( Fig. 2). The cams 36 will push out in legs 80 to the cam track 70 (fig. 6). Pressure within the flow bore 22 will need to be reduced to allow the tool 10 to move to the position shown in FIG. 3 and 7. Then fluid pressure can be time after time varied and increased within the flow bore 22, which will move the tool 10 to the second intermediate position shown in fig. 4 and 8, and the larger plug 86 will be released as the seat 52 is moved into the large diameter chamber portion 32c.

[0052] Conversely, only a larger plug 86 would be useful for moving the tool 10 from the second (open) operating position to the first (closed) operating position. If a smaller plug 84 were released with the intention of landing on the seat 52 when the tool 10 is in the second operating position (Figs. 3 and 7), it would pass through the central opening of the seat 52 when the seat 52 was located within the intermediate diameter chamber portion 32b. As a result, the tool 10, with the smaller plug 84, is unable to be moved to the second intermediate position (Figs. 4 and 8) because it will release the smaller plug 84 before the tool can reach the second intermediate position .

[0053] The sub-movements of the piston sleeve 44 and the indexing sleeve 56 described above, a damping assembly, which includes the damping chamber 38 and the damping piston 82, control the relative speed of these components within the housing 12. For example, as the piston sleeve 44 is moved axially downward within the housing 12 ( as it will when moving from the position shown in Fig. 1 to the position shown in Fig. 2), the attached damping piston 82 will be pressed downwards within the damping chamber 38. Fluid under the damping piston 82 within the damping chamber 38 must be transferred over the damping piston 82 through the nozzle 83 to accommodate the damping piston 82. This fluid transfer requires some time to pass because the nozzle 83 is restrictive. Therefore, the speed of movement of the damping piston 82 and the attached piston sleeve 44 is damped.

[0054] It will be understood that the tool 10 provides an actuation mechanism which presents a seat 52 which will release differently sized plugs 84 and 86 when the tool 10 is moved from each of two operating positions. It should also be noted that the tool 10 is operated using actuation plugs 84 and 86 which are of different sizes. Only the large plug 86 can close the tool 10, and only the small plug 84 can open the tool 10. As a result, it is easy for an operator to keep track of the internal positions of the tool 10. This element helps ensure that accidental return of tool 10 to its first operating position does not occur. This is because a smaller plug 84 will be released by the seat 52 before it moves the indexing sleeve 56 to the first operating position, and only the use of a larger plug 86 will work to return the tool 10 to its first operating position.

[0055] Figures 13-15 show an alternative plug seat 90 which can be incorporated within an alternative circulation valve tool 10'. Figures 13-14 show the seat 90 at a distance from the other components of the tool 10'. Figure 15 shows the seat 90 within the circulation valve tool 10'. The exemplary seat 90 includes a foundation ring 92 with a plurality of collets 94 extending axially therefrom. An arcuate segment 96 is formed at the distal (remote) end of each collet 94. The arcuate segments 96 each present an inwardly and upwardly directed seating surface 98 (see Fig. 15) upon which a plug 84 or 86 may be disposed.

[0056] Once the arcuate segments are located in the differently sized chamber portions 32a, 32b and 32c, they can be expanded away from each other or moved closer together, in the same manner as described earlier with respect to the seat 52, as plugs 84 or 86 is arranged. Plugs 84 or 86 are landed by placing them in the flow bore of the set string and into the flow bore of the casing 12. The plugs 84 or 86 will pass through the foundation ring 92 and land on the seating surfaces 98 of the arcuate segments 96. The use of collets 94 and the foundation ring 92 for holding the arcuate segments 96 provides stability for the arcuate segments 96 and prevents them from rotating during operation and possibly being misplaced.

[0057] In certain embodiments, some of the segments 96 exhibit an internal diameter greater than the diameter of one or more neighboring segments 96, thus providing the flow-through element described above.

[0058] It should be understood that the invention provides for plug capture and release mechanisms which are useful in hydraulically actuated tools, such as the tools 10 and 10' which are used in relation to underground hydrocarbon production. In particularly exemplary embodiments, the capture and release mechanisms include the expansion chamber 32 of the tool 10, 10' as well as seats 52 and 90 which allow plugs 84 and 86 to be selectively captured and released.

[0059]The foregoing description is directed to particular embodiments of the present invention for purposes of illustration and explanation. However, it will be obvious to someone skilled in the field that many modifications and changes in the embodiments presented above are possible without deviating from the scope and idea of the invention.

Claims (20)

1. A trap and release mechanism for use in an underground hydrocarbon production related tool that is hydraulically actuated, characterized in that the capture and release mechanism comprises: an expansion chamber formed within the tool and having a plurality of chamber portions of different diameters; a seat for capturing and releasing a plug, the seat being held within the expansion chamber and formed of a plurality of separate arcuate segments forming an annular seat with a central opening; and wherein the central opening to the seat has a first diameter when the seat is arranged within one of said plurality of chamber portions and a second diameter that is larger than the first diameter when the ball seat is arranged within another of said chamber portions. 2. Catch and release mechanism according to claim 1, wherein at least one of said arcuate segments has a larger internal diameter than at least another of said arcuate segments, thereby allowing fluid to flow through the seat when a plug is provided on the seat . 3. Capture and release mechanism according to claim 1, characterized in that it further comprises: an annular foundation ring; and a plurality of clamping sleeves connecting each arcuate segment to the foundation ring. 4. Capture and release mechanism according to claim 1, characterized in that the seat is placed on a piston sleeve which is axially movable within a housing of the tool and in which axial movement of the piston sleeve within the housing causes the tool to change operating positions. 5. Capture and release mechanism according to claim 1, characterized in that there are three chamber parts and in which the central opening has a third diameter when the seat is placed within the third chamber part. 6. Capture and release mechanism according to claim 4, characterized in that the tool can be repetitively cycle-controlled between operating positions. 7. A tool for use in an underground hydrocarbon production facility, characterized in that it comprises: a housing forming an axial flow bore and having an outer lateral fluid port formed therein; a piston sleeve axially movable within the flow bore and with an internal lateral fluid port, the piston sleeve is movable between a first position corresponding to a first operating position for the tool, and a second position corresponding to a second operating position for the tool; and an actuation mechanism for moving the tool between the first and second operating positions, the actuation mechanism comprising a seat connected to the piston sleeve for capturing and releasing a plug, the seat being held within the expansion chamber and formed by a plurality of separate arcuate segments forming an annular seat with a central opening; wherein: a) the actuation mechanism moves the tool from the first operating position to the second operating position by landing a first actuating plug on the seat and then varying fluid pressure within the flow bore of the housing; b) the actuation mechanism moves the tool from the second operating position to the first operating position by landing a second actuating plug of a size different from the first actuating plug on the seat and then varying fluid pressure within the flow bore of the housing; a first actuation plug; and a second actuation plug having a different size than the first actuation plug. 8. Tool according to claim 7, characterized in that the actuation mechanism further comprises: an expansion chamber formed in the housing, the expansion chamber having a plurality of chamber portions of different diameters, wherein the central opening of the seat provides a first diameter when the seat is placed within one of said plurality of chamber portions; and the central opening provides a second diameter when the seat is placed within another of said chamber portions. 9. Tool according to claim 8, characterized in that there are three chamber parts and in which the central opening has a third diameter when the seat is placed within a third chamber part. 10. Tool according to claim 7, characterized in that it further comprises an indexing mechanism which controls the axial position of the piston sleeve with respect to the housing. 11. Tool according to claim 9, characterized in that at least one of said arc-shaped segments of the seat has a larger internal diameter than at least another of said arc-shaped segments and thereby allows fluid to flow through the seat when a plug is placed on the seat. 12. Tool according to claim 7, characterized in that the seat further comprises: an annular foundation ring; and a plurality of clamping sleeves connecting each arcuate segment to the foundation ring. 13. Tool according to claim 9, characterized in that it further comprises a damping assembly for controlling speed of relative axial movement of the piston sleeve with respect to the housing, the damping assembly comprising: a damping chamber formed between the housing and the piston sleeve, the damping chamber being filled with a fluid; a damping piston attached to the piston sleeve located within the damping chamber; and a restricting nozzle provided through the piston to allow fluid to be transferred over the piston. 14. A circulation valve tool for use in underground hydrocarbon production and characterized in that it comprises: a housing forming an axial flow bore and having an outer lateral fluid port formed therein; a piston sleeve axially movable within the flow bore and with an internal lateral fluid port, the piston sleeve is movable between a first position corresponding to a first operating position for the tool, and a second position corresponding to a second operating position for the tool; an actuation mechanism for moving the tool between the first and second operating positions, the actuation mechanism comprising a seat connected to the piston sleeve, the seat comprising a plurality of separate arcuate segments forming an annular seat with a central opening; wherein the actuation mechanism moves the tool from the first operating position to the second operating position by landing a first actuating plug on the seat and then varying fluid pressure within the flow bore of the housing; and wherein the actuation mechanism moves the tool from the second operating position to the first operating position by landing a second actuating plug of a size different from the first actuating plug on the seat and then varying fluid pressure within the flow bore of the housing. 15. Tool according to claim 14, characterized in that at least one of said arc-shaped segments of the seat has a larger inner diameter than at least another of said arc-shaped segments, thereby allowing fluid flow through the seat when a plug is placed on the seat. 16. Tool according to claim 14, characterized in that the seat further comprises: an annular foundation ring; and a plurality of clamping sleeves connecting each arcuate segment to the foundation ring. 17. Tool according to claim 14, characterized in that the actuation mechanism further comprises: an expansion chamber formed in the housing, the expansion chamber having a plurality of chamber portions of different diameters, wherein the central opening of the seat provides a first diameter when the seat is placed within one of said plurality of chamber portions; and the central opening has a second diameter which is larger than the first diameter when the seat is placed within another of said chamber parts. 18. Tool according to claim 14, characterized in that there are three chamber parts and in which the central opening has a third diameter when the seat is placed within a third chamber part. 19. Tool according to claim 14, characterized in that it further comprises an indexing mechanism which controls the axial position of the piston sleeve with respect to the housing. 20. Tool according to claim 14, characterized in that the tool can be repetitively cycle-controlled between the first and second operating positions.