RECIPROCATING DRIVE APPARATUS

Abstract

A reciprocating drive apparatus (10) comprises a housing (12) and a mandrel (14), wherein the mandrel (14) and the housing (12) are configurable to be rotated relative to each other. The apparatus (10) further comprises a reciprocating piston (16) mounted within a piston housing (18) to define a piston chamber (20a), wherein the piston (16) is moveable in reverse first and second axial directions (A,B), and a rotary valve assembly (24) comprising a valve inlet (28) for communicating with a pressure region (P) and a valve exhaust (30) for communicating with an exhaust region (E). The rotary valve assembly (24) is operated by relative rotation between the mandrel (14) and the housing (12) to be cyclically reconfigured between a pressure configuration and an exhaust configuration. When in the pressure configuration the piston chamber (20a) is in pressure communication with the valve inlet (28) and isolated from the valve exhaust (30) to permit the piston to move in the first axial direction (A) in accordance with the piston chamber being pressurised via the valve inlet (28). When in the exhaust configuration the piston chamber (20a) is isolated from the valve inlet (28) and in pressure communication with the valve exhaust (30) to permit the piston chamber to be depressurised and the piston (16) to move in the second axial direction (B). Movement of the piston (16) in at least one of the first and second axial directions (A,B) generates an applied force within the apparatus (10) and/or an applied force output from the apparatus (10).

Claims

1. A reciprocating drive apparatus, comprising: a housing and a mandrel configurable to be rotated relative to each other; a reciprocating piston mounted within a piston housing to define a piston chamber, wherein the piston is moveable in reverse first and second axial directions; and a rotary valve assembly comprising a valve inlet for communicating with a pressure region and a valve exhaust for communicating with an exhaust region, the rotary valve assembly being operated by relative rotation between the mandrel and the housing to be cyclically reconfigured between: a pressure configuration in which the piston chamber is in pressure communication with the valve inlet and isolated from the valve exhaust to permit the piston to move in the first axial direction in accordance with the piston chamber being pressurised via the valve inlet; and an exhaust configuration in which the piston chamber is isolated from the valve inlet and in pressure communication with the valve exhaust to permit the piston chamber to be depressurised and the piston to move in the second axial direction, wherein movement of the piston in at least one of the first and second axial directions generates an applied force within the apparatus and/or an applied force output from the apparatus.

2. The apparatus of claim 1, comprising an axial throughbore.

3. The apparatus of claim 1, wherein one of the housing and the mandrel defines the valve exhaust.

4. The apparatus of claim 1, wherein one of the mandrel and the housing defines the valve inlet.

5. The apparatus of claim 1, wherein the valve inlet and valve exhaust are separate from each other.

6. The apparatus of claim 1, wherein the mandrel and the housing are configurable between: a first configuration in which the mandrel and the housing are rotatably fixed such that the mandrel and the housing are configured to rotate together; and a second configuration in which the mandrel and the housing are released for relative rotation.

7. The apparatus of claim 2, wherein the rotary valve assembly is configured to facilitate selective fluid communication between the valve inlet and the axial throughbore.

8. The apparatus of claim 1, wherein the mandrel and the housing are configured so as to define an axial flow passage therebetween, wherein the rotary valve assembly is configured to facilitate selective fluid communication between the axial flow passage defined between the mandrel and the housing and the piston chamber.

9. (canceled)

10. The apparatus of claim 1, wherein the rotary valve assembly forms a first rotary valve assembly of a rotary valve arrangement of the apparatus, and the rotary valve arrangement comprising a second rotary valve assembly.

11. The apparatus of claim 10, wherein the first rotary valve assembly and the second rotary valve assembly are disposed either side of and/or communicate with respective sides of the piston.

12. The apparatus of claim 10, wherein the first rotary valve assembly forms a first biasing arrangement of the apparatus and the second rotary valve assembly forms a second biasing arrangement of the apparatus.

13. The apparatus of claim 1, wherein the apparatus comprises a single rotary valve assembly in the form of said rotary valve assembly.

14. The apparatus of claim 13, wherein the rotary valve assembly forms a first biasing arrangement of the apparatus and the apparatus comprises a second biasing arrangement.

15. The apparatus of claim 14, wherein the second biasing arrangement comprises a mechanical biasing arrangement.

16. (canceled)

17. The apparatus of claim 1, wherein the rotary valve assembly comprises at least one rotary valve member which is rotatably fixed to one of the housing and the mandrel.

18. The apparatus of claim 2, wherein: the apparatus is configurable in a first, open, configuration which permits access through the axial throughbore, and the apparatus is configurable in a second, obturated, configuration in which access through the apparatus is restricted or blocked, said second configuration providing an elevated fluid pressure or fluid pressure differential within the axial throughbore for use by the apparatus.

19. The apparatus of claim 18, wherein the apparatus comprises, is coupled to or operatively associated with a valve arrangement configured to generate the elevated pressure for use by the apparatus, wherein the valve arrangement comprises a valve member and an actuator for reconfiguring the valve member from the open configuration to the obturated configuration in which fluid flow through the valve arrangement is prevented or restricted.

20. The apparatus of claim 19, wherein the valve arrangement is configured to provide selective fluid communication through the axial throughbore of the apparatus.

21. The apparatus of claim 19, wherein a valve member of the valve arrangement comprises an orifice, whereby the orifice is configured so that fluid through the orifice chokes flow and generates the elevated pressure for use by the apparatus, said elevated pressure taking the form of a back pressure.

22. The apparatus of claim 19, wherein the valve arrangement comprises, is coupled to or operatively associated with an indexer mechanism.

23. The apparatus of claim 22, wherein the indexer mechanism comprises one or more dogs, the one or more dogs disposed on the mandrel such that relative axial movement of the mandrel and the housing de-supports the dogs and permits axial movement of the actuator.

24. The apparatus of claim 1, wherein the apparatus comprises or takes the form of a jarring apparatus.

25.-27. (canceled)

28. The apparatus of claim 1, wherein the apparatus comprises or takes the form of a hammer apparatus.

29. The apparatus of claim 1, wherein the apparatus comprises or takes the form of a reciprocator apparatus.

30. A tool comprising the apparatus of claim 1, wherein the tool comprises or defines at least one of a downhole tool, a hammer tool including at least one of an axial hammer tool and a radial hammer tool, a pump tool and a packer tool.

31.-35. (canceled)

36. A method for generating forces, the method comprising: establishing relative rotation between a housing and a mandrel to operate a rotary valve assembly, the rotary valve assembly comprising a valve inlet for communicating with a pressure region and a valve exhaust for communicating with an exhaust region, such that the rotary valve assembly is cyclically reconfigured between: a pressure configuration in which a piston chamber is in pressure communication with the valve inlet and isolated from the valve exhaust to permit a reciprocating piston to move in the first axial direction in accordance with the piston chamber being pressurised via the valve inlet; and an exhaust configuration in which the piston chamber is isolated from the valve inlet and in pressure communication with the valve exhaust to permit the piston chamber to be depressurised and the piston to move in the second axial direction, wherein movement of the piston in at least one of the first and second axial directions generates an applied force within the apparatus and/or an applied force output from the apparatus.

37. An apparatus comprising: a throughbore; a pressure operated jarring mechanism operable by fluid pressure to generate jarring forces within the apparatus, wherein the pressure operated jarring mechanism is in pressure communication with the throughbore; and a pressure control mechanism within the throughbore, wherein the pressure control mechanism is selectively variable within the throughbore to permit pressure to be varied within the throughbore for use in operating the pressure operated jarring mechanism.

38. The apparatus of claim 37, wherein the pressure control mechanism is configurable between a first, open, configuration which permits access through the throughbore and a second, obturated, configuration in which access through the throughbore is restricted or blocked, said restriction or blockage permitting fluid pressure to be elevated within the throughbore for use in operating the pressure operated mechanism.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0456] These and other aspects will now be described with reference to the accompanying drawings, in which:

[0457] FIG. 1 shows a longitudinal sectional view of a reciprocating drive apparatus in the form of a jarring apparatus;

[0458] FIG. 2 shows cross-sectional view A-A of the jarring apparatus shown in FIG. 1;

[0459] FIG. 3 shows cross-sectional view B-B of the jarring apparatus shown in FIG. 1;

[0460] FIG. 4 shows cross-sectional view C-C of the jarring apparatus shown in FIG. 1;

[0461] FIG. 5 shows cross-sectional view D-D of the jarring apparatus shown in FIG. 1;

[0462] FIG. 6 shows the jarring apparatus shown in FIG. 1, in a first phase of rotation;

[0463] FIG. 7 shows the jarring apparatus shown in FIG. 1, in a second phase of rotation;

[0464] FIG. 8 shows cross-sectional view A-A of the jarring apparatus shown in FIG. 7;

[0465] FIG. 9 shows cross-sectional view B-B of the jarring apparatus shown in FIG. 7;

[0466] FIG. 10 shows cross-sectional view C-C of the jarring apparatus shown in FIG. 7;

[0467] FIG. 11 shows cross-sectional view D-D of the jarring apparatus shown in FIG. 7;

[0468] FIG. 12 shows a diagrammatic view of the jarring apparatus showing the relative position and state of components of the apparatus at different angular positions;

[0469] FIG. 13 shows a longitudinal sectional view of a downhole tool comprising the jarring apparatus of FIG. 1, in a first phase of rotation;

[0470] FIGS. 14 and 15 show a valve arrangement configured to generate back pressure for use in operation of the jarring apparatus;

[0471] FIG. 16 shows a longitudinal sectional view of the downhole tool of FIG. 13, primed for performing a jarring operation;

[0472] FIG. 17 shows a perspective view of the valve arrangement shown in FIGS. 14 and 15 configured to generate back pressure for use in operation of the jarring apparatus;

[0473] FIG. 18 shows a longitudinal sectional view of the downhole tool shown in FIG. 13, in a second phase of rotation;

[0474] FIGS. 19 to 23 show an alternative valve arrangement for the jarring apparatus;

[0475] FIGS. 24 and 25 show alternative biasing arrangements for the jarring apparatus;

[0476] FIG. 26 shows a tool comprising an alternative jarring apparatus;

[0477] FIG. 27 shows part of an alternative jarring apparatus, in a first phase of rotation;

[0478] FIG. 28 shows the part of the jarring apparatus shown in FIG. 27, in a second phase of rotation;

[0479] FIG. 29 shows a longitudinal sectional view of an alternative reciprocating drive apparatus, in a first phase of rotation;

[0480] FIG. 30 shows cross-sectional view A-A of the apparatus shown in FIG. 29;

[0481] FIG. 31 shows a longitudinal sectional view of the apparatus shown in FIG. 29, in a second phase of rotation;

[0482] FIG. 32 shows cross-sectional view B-B of the apparatus shown in FIG. 29;

[0483] FIG. 33 shows a downhole tool comprising the apparatus of FIG. 29;

[0484] FIG. 34 shows a longitudinal sectional view of the downhole tool shown in FIG. 33;

[0485] FIG. 35 shows a longitudinal sectional view of another downhole tool comprising an alternative reciprocating drive apparatus, in a first phase of rotation;

[0486] FIG. 36 shows cross-sectional view A-A of the downhole tool shown in FIG. 35;

[0487] FIG. 37 shows a longitudinal sectional view of the downhole tool shown in FIG. 35, in a second phase of rotation;

[0488] FIG. 38 shows cross-sectional view B-B of the downhole tool shown in FIG. 37;

[0489] FIG. 39 shows a longitudinal sectional view of an alternative reciprocating drive apparatus, in a first phase of rotation and with the output shaft in an extended position;

[0490] FIG. 40 shows cross-sectional view A-A of the apparatus shown in FIG. 39;

[0491] FIG. 41 shows another longitudinal sectional view of the apparatus shown in FIG. 39 and with the output shaft in a retracted position;

[0492] FIG. 42 shows cross-sectional view B-B of the apparatus shown in FIG. 41;

[0493] FIG. 43 shows a longitudinal sectional view of the apparatus shown in FIG. 39, in a second phase of rotation;

[0494] FIG. 44 shows cross-sectional view C-C of the apparatus shown in FIG. 43;

[0495] FIG. 45 shows a longitudinal sectional view of the apparatus shown in FIG. 39, in a third phase of rotation;

[0496] FIG. 46 shows cross-sectional view D-D of the apparatus shown in FIG. 45;

[0497] FIG. 47 shows a longitudinal sectional view of an alternative reciprocating drive apparatus, in a first phase of rotation;

[0498] FIG. 48 shows cross-sectional view A-A of the apparatus shown in FIG. 47;

[0499] FIG. 49 shows a longitudinal sectional view of the apparatus shown in FIG. 47, in a second phase of rotation;

[0500] FIG. 50 shows cross-sectional view B-B of the apparatus shown in FIG. 49;

[0501] FIG. 51 shows a longitudinal sectional view of an alternative reciprocating drive apparatus, in a first phase of rotation;

[0502] FIG. 52 shows cross-sectional view A-A of the apparatus shown in FIG. 51;

[0503] FIG. 53 shows a longitudinal sectional view of the apparatus shown in FIG. 51, in a second phase of rotation;

[0504] FIG. 54 shows cross-sectional view B-B of the apparatus shown in FIG. 51.

[0505] FIG. 55 shows a longitudinal sectional view of a pump tool comprising the apparatus shown in FIGS. 51 to 54; and

[0506] FIG. 56 shows a longitudinal sectional view of a packer tool comprising the apparatus shown in FIGS. 51 to 54.

DETAILED DESCRIPTION OF THE DRAWINGS

[0507] Referring first to FIG. 1 of the accompanying drawings, there is a jarring apparatus 10 for generating jarring forces.

[0508] In use, the jarring apparatus 10 may be utilised to generate jarring forces for use in a range of different downhole applications. For example, the jarring apparatus 10 may be utilised to generate jarring forces to a stuck object, such as a stuck tool, drill bit, drill string, bottom hole assembly (BHA) and the like. Alternatively or additionally, the jarring apparatus 10 may be utilised to generate jarring forces during the process of drilling, for example to apply a hammer drilling effect. The jarring apparatus 10 may also be operable to generate jarring forces for use in pulling equipment, tools and infrastructure from a wellbore, for example in the process of removing casing, and/or for other downhole jarring applications such as piling, for example. It will be recognised that while the jarring apparatus 10 is particularly beneficial in downhole applications (which pose particular challenges due to the need to manipulate equipment at significant distance from surface, e.g. several kilometres, and in the case of high angle or horizontal wells with restricted ability to apply forces in the non-vertical section) the jarring apparatus 10 may be utilised in a range of different applications and environments.

[0509] Referring now also to FIGS. 2 to 5 which show cross-sectional views A-A, B-B, C-C and D-D of the jarring apparatus 10, the jarring apparatus 10 comprises a housing 12 and a mandrel 14. The mandrel 14 is mounted within the housing 12, the mandrel 14 and the housing 12 configurable to be rotated relative to each other. The jarring apparatus 10 further comprises a jarring piston 16 mounted within a piston housing 18 to define first and second piston chambers 20a,20b. The jarring piston 16 is moveable within the first and second piston chambers 20a,20b in reverse first and second axial directions A, B.

[0510] The jarring apparatus 10 further comprises a rotary valve arrangement, generally denoted 22. As shown in FIG. 1, the rotary valve arrangement 22 comprises a first, upper, valve assembly, generally denoted 24, and a second, lower, valve assembly, generally denoted 26.

[0511] The upper rotary valve assembly 24 comprises a valve inlet 28 (which for ease of reference will be referred to below as upper valve inlet 28) for communicating with a pressure region P and a valve exhaust 30 (which for ease of reference will be referred to below as upper valve exhaust 30) for communicating with an exhaust region E.

[0512] FIG. 2 of the accompanying drawings shows cross section A-A through the upper valve inlet 28 of the jarring apparatus 10. FIG. 3 shows cross section B-B through the upper valve exhaust 30 of the jarring apparatus 10.

[0513] The upper rotary valve assembly 24 is operated by relative rotation between the mandrel 14 and the housing 12 to be cyclically reconfigured between: a pressure configuration in which the piston chamber 20a is in pressure communication with the upper valve inlet 28 and isolated from the upper valve exhaust 30 to permit the jarring piston 16 to move in the first axial direction A in accordance with the piston chamber 20a being pressurised via the upper valve inlet 28; and an exhaust configuration in which the piston chamber 20a is isolated from the upper valve inlet 28 and in pressure communication with the upper valve exhaust 30 to permit the piston chamber 20a to be depressurised and the jarring piston 16 to move in the second axial direction B. Movement of the jarring piston 16 in at least one of the first and second axial directions A, B generates a jarring force within the jarring apparatus 10, as will be described further below.

[0514] The lower rotary valve assembly 26 comprises a valve inlet 32 (which for ease of reference will be referred to below as lower valve inlet 32) which communicates with the pressure region P and a valve exhaust 34 (which for ease of reference will be referred to below as lower valve exhaust 34) for communicating with the exhaust region E.

[0515] FIG. 4 shows cross section C-C through the lower valve exhaust 34 of the jarring apparatus 10. FIG. 5 shows cross section D-D through the lower valve inlet 32 of the jarring apparatus 10.

[0516] The lower rotary valve assembly 26 is operated by relative rotation between the mandrel 14 and the housing 12 to be cyclically reconfigured between: a pressure configuration in which the piston chamber 20b is in pressure communication with the lower valve inlet 32 and isolated from the lower valve exhaust 34 to permit the jarring piston 16 to move in the second axial direction B in accordance with the piston chamber 20b being pressurised via the lower valve inlet 32; and an exhaust configuration in which the piston chamber 20b is isolated from the lower valve inlet 32 and in pressure communication with the lower valve exhaust 34 to permit the piston chamber 20b to be depressurised and the jarring piston 16 to move in the first axial direction A.

[0517] It will be recognised that in the illustrated jarring apparatus 10, the upper rotary valve assembly 24 and the lower rotary valve assembly 26 may be configured to co-operate, with the pressure configuration of the upper rotary valve assembly 24 coinciding with the exhaust configuration of the lower rotary valve assembly 26.

[0518] While in the illustrated apparatus 10, the rotary valve arrangement 22 comprises two valve assemblies 24, 26, the rotary valve arrangement 22 may comprise a single valve assembly 24;26 (an example of which is described below with reference to FIGS. 25 and 26).

[0519] In use, movement of the jarring piston 16 in the first and second axial directions A, B generates jarring forces within the apparatus 10 as will be described further below.

[0520] Continued relative rotation between the housing 12 and the mandrel 14 operates the rotary valve arrangement 22 to cause the piston chambers 20a,20b to be cyclically pressurised and depressurised to permit reciprocating movement of the jarring piston 16 to generate repeated jarring forces within the apparatus 10. As jarring forces are generated by relative rotation between the mandrel 14 and the housing 12, the illustrated jarring apparatus 10 may be defined as a rotary jarring apparatus 10.

[0521] The frequency of generated jarring forces will be a function of the number and/or configuration of ports of the rotary valve arrangement 22 and the relative rotational speed between the mandrel 14 and the housing 12, which may be infinitely variable to thus provide infinite variability of the jarring frequency, providing significant advantages.

[0522] Moreover, as jarring forces are generated as a result of fluid pressure, the illustrated jarring apparatus 10 may be defined as a fluid actuated jarring apparatus 10, for example a hydraulically actuated jarring apparatus 10, the jarring apparatus 10 providing an alternative solution to jarring apparatus in which a jarring mass (e.g., hammer) is displaced using a mechanical system, such as a cam system which may need to accommodate significant loading and wear tolerance and thus may present difficult design challenges. Further, by using fluid pressure the magnitude of jarring forces may be readily varied, at least in some implementations, by varying fluid pressure without necessarily requiring the same considerations around the force limitations of mechanical displacement systems.

[0523] In use, the jarring apparatus 10 is used in combination with the pressure and exhaust regions P,E such that a pressure differential is applied across the rotary valve arrangement 22. Specifically, the pressure within the pressure region P is elevated above the pressure in the exhaust region E. In particular, the pressure within the pressure region P is sufficient (for example sufficiently high) to pressurise the piston chamber 20a to permit the jarring piston 16 to move in the first axial direction A (to the right as shown in FIG. 1), and the pressure within the exhaust region E is sufficient (for example sufficiently low) to permit the piston chamber 20a to be depressurised and the jarring piston 16 to move in the second axial direction B (to the left as shown in FIG. 1).

[0524] The jarring apparatus 10 is configured to operate irrespective of the direction of the pressure differential applied across the rotary valve arrangement 22. As an example, in one mode of operation, suggested above, the pressure of the pressure region P is higher than the pressure of the exhaust region E. However, should the pressure differential be reversed then what was previously the pressure region P becomes the exhaust region E, and vice versa, and what was previously the valve inlet becomes the valve exhaust, and vice versa.

[0525] In this respect, it should be recognised that the valve inlet and the pressure region P, and valve exhaust and exhaust region E, may be defined as such in accordance with the direction of an applied pressure differential applied across the rotary valve arrangement 22. With this in mind, although features will be defined herein as relating to the valve inlet and valve exhaust (and pressure and exhaust regions P,E), this is done so for clarity and brevity purposes and it should be understood that the function and thus identity of the valve inlet and valve exhaust (and pressure and exhaust regions P,E) could switch depending on the operational conditions.

[0526] Similarly, it should be recognised that the terms upper and lower, uphole and downhole, up and down and the like are for ease of reference since the jarring apparatus 10 may be used in any orientation. The term upper or uphole may for example but not exclusively be considered as proximal and the term lower may for example but not exclusively be considered to represent distal.

[0527] This ability for the jarring apparatus 10 to operate irrespective of the direction of the pressure differential applied across the rotary valve arrangement 22 is possible without requiring an operator to undertake any modification to the apparatus 10, for example modifications in-situ or by recovery and re-deploying, which may be complex and time consuming.

[0528] The ability for the jarring apparatus 10 to be employed irrespective of the direction of the pressure differential applied across the rotary valve arrangement 22 provides significant advantages. For example, this arrangement could provide contingency in the event that the ability to establish a pressure differential in one direction becomes compromised, for example where one of the pressure and exhaust regions suffers a failure preventing pressure to be elevated therein to the required level. Further, the flexibility of the jarring apparatus 10 to function irrespective of the direction of the pressure differential may provide advantages in allowing the same jarring apparatus 10 to be used in multiple different applications where a particular pressure differential direction is preferred.

[0529] As described above, the jarring apparatus 10 comprises housing 12 and mandrel 14 mounted within the housing 12. The mandrel 14 is rotatably and axially coupled to the housing 12. It will be understood that reference to relative rotation between the housing 12 and the mandrel 14 may include the jarring apparatus 10 being configured such that: the mandrel 14 rotates while the housing 12 is stationary; such that the housing 12 rotates while the mandrel 14 is stationary; or such that the mandrel 14 and the housing 12 both rotate. Beneficially, this facilitates flexibility in that jarring operations may be carried out in a number of different operational scenarios.

[0530] As shown in FIG. 1, the housing 12 is disposed around the mandrel 14 and is generally tubular in construction. In the illustrated jarring apparatus 10, the housing 12 comprises a plurality of components coupled together. Construction of the housing 12 in such a manner facilitate ease of manufacture and assembly. However, it will be recognised that the housing 12 may alternatively comprise a single component.

[0531] The housing 12 comprises one or more lateral flow passages 36U,36L in the form of flow ports through a circumferential wall of the housing 12, the lateral flow passages 36U forming the upper valve exhaust 30 and the lateral flow passages 36L forming the lower valve exhaust 34. In the illustrated jarring apparatus 10, the lateral flow passages 36U,36L are arranged circumferentially and axially.

[0532] The lateral flow passages 36U,36L straddle the piston housing 18, with a plurality of the lateral flow passages 36U,36L being disposed at a first, uphole, location relative to the piston housing 18 and a plurality of the lateral flow passage 36U,36L being disposed at a second, downhole, location relative to the piston housing 18.

[0533] The mandrel 14 is generally tubular in construction and defines an axial throughbore 38 of the jarring apparatus 10. The axial throughbore 38 is configured, i.e., shaped and/or dimensioned, to permit passage of fluid and/or tools through the jarring apparatus 10.

[0534] Beneficially, the jarring apparatus 10 may form part of a tool string and so the ability to permit passage of fluid and/or tools through the jarring apparatus 10 facilitates access through the jarring apparatus 10, for example to operate tools positioned downhole of the jarring apparatus 10.

[0535] In the illustrated jarring apparatus 10, the mandrel 14 comprises a plurality of components coupled together by a coupling arrangement. Construction of the mandrel 14 in such a manner facilitates ease of manufacture and assembly. However, it will be recognised that the mandrel 14 may alternatively comprise a single component.

[0536] As shown in FIG. 1, the mandrel 14 and the housing 12 are configured, e.g. shaped and/or dimensioned, so as to define an axial flow passage 40 therebetween, which in the illustrated jarring apparatus 10 is annular.

[0537] The mandrel 14 comprises one or more lateral flow passages 42U,42L in the form of flow ports through a circumferential wall of the mandrel 14, the lateral flow passages 42U forming the upper valve inlet 28 and the lateral flow passages 42L forming the lower valve inlet 32. In the illustrated jarring apparatus 10, the lateral flow passages 42 are arranged circumferentially and axially.

[0538] The lateral flow passages 42U,42L straddle the piston housing 18, with two of the lateral flow passages 42U being disposed at a first, uphole, location relative to the piston housing 18 and two of the lateral flow passages 42L being disposed at a second, downhole, location relative to the piston housing 18.

[0539] An upper portion of the axial flow passage 40 provides fluid communication between the upper valve inlet 28, the upper valve exhaust 30 and the upper piston chamber 20a, although as will be described below the upper valve assembly 24 is configured to provide selective fluid communication either between the upper valve inlet 28 and the upper piston chamber 20a via the axial flow passage 40 or between the upper valve exhaust and the piston chamber 20a via the axial flow passage 40.

[0540] A lower portion of the axial flow passage 40 provides fluid communication between the lower valve inlet 32, the lower valve exhaust 34 and the lower piston chamber 20b, although as will be described below the lower valve assembly 26 is configured to provide selective fluid communication either between the lower valve inlet 32 and the lower piston chamber 20b via the axial flow passage 40 or between the lower valve exhaust 34 and the piston chamber 20b via the axial flow passage 40.

[0541] As shown in FIGS. 1 and 2, the upper rotary valve assembly 24 comprises a rotary valve member 44 operatively associated with the upper valve inlet 28. In the illustrated jarring apparatus 10, the rotary valve member 44 takes the form of an inlet selector sleeve. The rotary valve member 44 and the upper valve inlet 28 are configured for relative rotation to each other such that rotation causes the rotary valve member 44 to selectively block or obturate the upper valve inlet 28. That is, during one phase of relative rotation, the valve inlet 28 defines an open configuration in which pressure communication with the piston chamber 20a is permitted and in another phase the valve inlet 28 defines the closed configuration in which pressure communication with the piston chamber 20a is prevented, substantially prevented or obturated.

[0542] In the illustrated jarring apparatus 10, the rotary valve member 44 is rotatably fixed relative to the housing 12 by a key arrangement 46.

[0543] As shown in FIGS. 1 and 2, the rotary valve member 44 comprises a number of lateral flow passages 48, which in the illustrated apparatus 10 take the form of elongate slots disposed through the rotary valve member 44. Seal elements 50 in the form of rotary seal elements are disposed in annular grooves 51 provided on an inner circumferential surface of the rotary valve member 44. As shown, the seal elements 50 straddle the lateral flow passages 48 and provide sealing between the rotary valve member 44 and the mandrel 14.

[0544] As shown in FIGS. 1 and 3, the upper rotary valve assembly 24 comprises a rotary valve member 52 operatively associated with the upper valve exhaust 30. In the illustrated jarring apparatus 10, the rotary valve member 52 takes the form of an outlet selector sleeve. The rotary valve member 52 and the upper valve exhaust 30 are configured for relative rotation to each other such that rotation causes the rotary valve member 52 to selectively block or obturate the upper valve exhaust 30. That is, during one phase of relative rotation, the upper valve exhaust 30 defines an open configuration in which pressure communication with the upper piston chamber 20a is permitted. In another phase, the upper valve exhaust 30 defines the closed configuration in which pressure communication with the upper piston chamber 20a is prevented, substantially prevented or obturated.

[0545] In the illustrated jarring apparatus 10, the rotary valve member 52 is rotatably fixed relative to the mandrel 14 by a key arrangement 54.

[0546] As shown in FIGS. 1 and 3, the rotary valve member 52 comprises a number of lateral flow passages 56, which in the illustrated apparatus 10 take the form of elongate slots disposed through the rotary valve member 52. Seal elements 58 in the form of rotary seal elements are disposed in annular grooves 60 provided on an outer circumferential surface of the rotary valve member 52. As shown, the seal elements 58 straddle the lateral flow passages 56 and provide sealing between the rotary valve member 52 and the housing 12.

[0547] In a similar arrangement to that described above with respect to the upper rotary valve assembly 24, the lower rotary valve assembly 26 comprises a rotary valve member 62 operatively associated with the lower valve inlet. In the illustrated jarring apparatus 10, the rotary valve member 62 takes the form of an inlet selector sleeve. The rotary valve member 62 and the lower valve inlet 32 are configured for relative rotation to each other such that rotation causes the rotary valve member 62 to selectively block or obturate the lower valve inlet 32. That is, during one phase of relative rotation, the lower valve inlet 32 defines an open configuration in which pressure communication with the lower piston chamber 20b is permitted. In another phase, the lower valve inlet 32 defines a closed configuration in which pressure communication with the lower piston chamber 20b is prevented, substantially prevented or obturated.

[0548] In the illustrated jarring apparatus 10, the rotary valve member 62 is rotatably fixed relative to the housing 12 by fasteners 64.

[0549] As shown in FIGS. 1 and 5, the rotary valve member 62 comprises a number of lateral flow passages 66, which in the illustrated apparatus 10 take the form of elongate slots disposed through the rotary valve member 62. Seal elements 68 in the form of rotary seal elements are disposed in annular grooves 70 provided on an inner circumferential surface of the rotary valve member 62. As shown, the seal elements 68 straddle the lateral flow passages 66 and provide sealing between the rotary valve member 62 and the mandrel 14.

[0550] As shown in FIGS. 1 and 4, the lower rotary valve assembly 26 comprises a rotary valve member 72 operatively associated with the lower valve exhaust 34. In the illustrated jarring apparatus 10, the rotary valve member 72 takes the form of an outlet selector sleeve. The rotary valve member 72 and the lower valve exhaust 34 are configured for relative rotation to each other such that rotation causes the rotary valve member 72 to selectively block or obturate the lower valve exhaust 34. That is, during one phase of relative rotation, the lower valve exhaust 34 defines an open configuration in which pressure communication with the upper piston chamber 20b is permitted. In another phase, the lower valve exhaust 34 defines a closed configuration in which pressure communication with the lower piston chamber 20b is prevented, substantially prevented or obturated.

[0551] In the illustrated jarring apparatus 10, the rotary valve member 72 is rotatably fixed relative to the mandrel 14 by a key arrangement 74.

[0552] As shown in FIGS. 1 and 4, the rotary valve member 72 comprises a number of lateral flow passages 76, which in the illustrated apparatus 10 take the form of elongate slots disposed through the rotary valve member 72. Seal elements 78 in the form of rotary seal elements are disposed in annular grooves 80 provided on an outer circumferential surface of the rotary valve member 72. As shown, the seal elements 78 straddle the lateral flow passages 76 and provide sealing between the rotary valve member 72 and the housing 12.

[0553] As described above, the jarring piston 16 is mounted within the piston housing 18 to define the piston chambers 20a,20b, the jarring piston 16 being moveable in the reverse first and second axial directions A,B.

[0554] The jarring apparatus 10 comprises co-operating impact surfaces, wherein engagement of the impact surfaces results in the generation of the jarring forces.

[0555] A first impact surface 82 is provided on the jarring piston 16, and more particularly on an axial end face of a hammer 84 coupled to and carried by the jarring piston 16. As shown in FIG. 2, the hammer 84 is coupled to the jarring piston 16 by fasteners 86. A seal arrangement 88 is interposed between the hammer 84 and the housing 12 and between the hammer 84 and the mandrel 14.

[0556] A second impact surface 90 is formed on an axial end face of an anvil 92. In the illustrated jarring apparatus 10, the anvil 92 takes the form of a separate component and is disposed in and carried by the housing 12.

[0557] In use, the upper rotary valve assembly 24 is operable by relative rotation between the mandrel 14 and the housing 12 to be cyclically reconfigured between the pressure configuration and the exhaust configuration, so as to move the jarring piston 16 in one of the first and second axial directions A,B, said movement of the jarring piston 16 engaging the first and second impact surfaces 82,90 to generate the jarring forces within the apparatus 10.

[0558] As shown in FIG. 1, movement of the jarring piston 16 in the first axial direction A (to the right as shown in FIG. 2) is limited by an end stop 94 which, in the illustrated jarring apparatus 10 takes the form of a rubber buffer element. However, it will be recognised that the end stop 94 may take any suitable form and in some examples may be replaced with a hammer and/or anvil such as described above.

[0559] Referring now to FIG. 6 of the accompanying drawings, there is shown a longitudinal sectional view of the jarring apparatus 10 in a first configuration corresponding to a first phase of rotation.

[0560] As shown in FIG. 6, in the first configuration the upper and lower valve inlets 28, 32 are in their closed configuration such that fluid communication between the axial throughbore 38 and the axial flow passage 40 between the mandrel 14 and the housing 12 is prevented or at least restricted. The upper and lower valve exhausts 30,34 also define their closed configuration such that fluid communication between the axial flow passage 38 and the exhaust region E is prevented or at least restricted.

[0561] FIGS. 7 to 11 of the accompanying drawings shows the jarring apparatus 10 in a second configuration corresponding to a second phase of rotation. FIG. 7 shows a longitudinal sectional view of the apparatus 10 while FIGS. 8 to 11 respectively show cross-sectional views A-A, B-B, C-C and D-D of the upper valve inlet 28, upper valve exhaust 30, lower valve exhaust 34 and lower valve inlet 32 of the jarring apparatus 10.

[0562] In this second configuration, the upper valve inlet 28 is in the closed configuration. The upper valve exhaust 30 is in the open configuration. The lower valve inlet 32 is in the open configuration (the open configuration is out of plane and so not shown in FIG. 7 but can be seen in FIG. 11). The lower valve exhaust 34 is in the closed configuration.

[0563] In this configuration, and by virtue of the lower valve inlet 32 being in the open configuration, fluid communication is provided between the axial throughbore 38 and the lower piston chamber 20b and is thus available to act on the jarring piston 16. By virtue of the upper valve exhaust 30 being in the open configuration, fluid communication is provided between the upper piston chamber 20a and the exhaust region E surrounding the jarring apparatus 10.

[0564] In use, where the fluid pressure within the axial throughbore 38 is greater than that present in the exhaust region E, a pressure differential acts across the jarring piston 16 which urges the jarring piston 16 in an uphole direction (to the left as shown in FIG. 7). By virtue of the upper valve exhaust 30 being in the open configuration, fluid present in the upper piston chamber 20a is vented into the exhaust region E, e.g. annulus surrounding the apparatus 10. The motive force resulting from the pressure differential is significant, causing the jarring piston 16 and the coupled hammer 84 to move rapidly into engagement with the anvil 92 and thereby create a jarring force within the apparatus 10.

[0565] As described above, the rotary valve arrangement 22 is operable by relative rotation between the mandrel 14 and the housing 12 to be cyclically reconfigured between the pressure configuration and the exhaust configuration, and FIG. 12 of the accompanying drawings shows a diagrammatic view of the jarring apparatus 10 showing the relative position and state of components of the apparatus 10 at different angular positions, i.e., the open or closed configurations of each of the upper valve inlet 28, the upper valve exhaust 30, the lower valve inlet 32, and the lower valve exhaust 34. The operational state of the jarring piston 16 and hammer 84, i.e. whether the jarring piston 16 is moving in an upward or uphole direction (“lifting”) or a downward or downhole direction (“dropping”) is also shown relative to angular position in FIG. 12.

[0566] Referring now to FIG. 13 of the accompanying drawings, there is shown a longitudinal sectional view of a tool T comprising the jarring apparatus 10. The illustrated tool T takes the form of a downhole tool for generating jarring forces for use in a number of downhole applications. However, it will be recognised that the jarring apparatus 10 (or apparatus 2010,3010,4010 described below) may be utilised with any suitable tool where there is a desire to generate jarring and/or agitation forces.

[0567] As shown in FIG. 13, the tool T comprises a top sub 96. The top sub 96 is generally tubular in construction having an axial throughbore 98 extending therethrough. An upper end portion of the top sub 96 defines a connector 100 for coupling the jarring apparatus to another component of the tool string S. In the illustrated tool T, the connector 100 takes the form of a female connector, more specifically a threaded box connector. A lower end portion of the top sub 96 defines a female profile 102 configured to the upper end of the mandrel 14. In the illustrated tool T, the top sub 96 further comprises stabiliser blades 104 for offsetting the tool T from a borehole, generally denoted H.

[0568] As shown in FIG. 13, the tool T further comprises a swivel, generally denoted 106. The swivel 106 may comprise a thrust assembly. The swivel 106 is interposed between the mandrel 14 and the housing 12. In the illustrated tool T, the swivel 106 includes a first thrust shoulder 108 provided on the mandrel 14, and a second thrust shoulder 110 provided on the housing 12.

[0569] In the configuration shown in FIG. 13, the first and second thrust shoulders 108,110 are axially separated and thus disengaged. However, in use relative axial movement between the mandrel 14 and housing 12 will bring the first and second thrust shoulders 108,110 into engagement, such that axial loading may be transmitted between the mandrel 14 and the housing 12 via the swivel 106, thus diverting such loading from other components within the apparatus 10. The swivel 106 permits rotation between the first and second thrust shoulders 108,110 when engaged, such that the swivel 106 may function as a thrust bearing arrangement.

[0570] The swivel 106 comprises a plurality of axially arranged thrust bearing assemblies 112. Beneficially, the thrust bearing assemblies 112 share the axial load force exerted on the swivel 106.

[0571] The thrust bearing assemblies 112 each comprise thrust bearings 114. In the illustrated jarring apparatus 10, the thrust bearings 114 take the form of PTFE thrust plain bearings, although it will be understood that any suitable thrust bearings may be utilised.

[0572] The thrust bearing assemblies 112 also comprise a carrier member 116, the thrust bearings 114 being disposed on and carried by the carrier member 116. In the illustrated jarring apparatus 10, the carrier member 116 takes the form of an annular sleeve.

[0573] As shown in FIG. 13, the tool T further comprises a shoulder 118 defined by an axial end face of a portion of the mandrel 14. In use, relative axial movement of the housing 12 and the mandrel 14 brings the shoulder 118 into engagement with an anvil 120 disposed in the housing 12.

[0574] As described above, the mandrel 14 is rotatably and axially coupled to the housing 12 and as shown in FIG. 13 the jarring apparatus 10 comprises a spline connection 122 for rotationally and axially coupling the mandrel 14 to the housing 12.

[0575] As shown in FIG. 13, the jarring apparatus 10 further comprises a seal arrangement 124, which in the illustrated jarring apparatus 10 takes the form of a seal stack, and ports 126. The seal arrangement 124 is radially interposed between the mandrel 14 and the housing 12. When seated, the seal arrangement 124 prevents fluid communication to the thrust assembly 106. When unseated by relative axial movement between the mandrel 14 and the housing 12, the ports 126 provide fluid communication to the thrust assembly 106, acting to cool and/or lubricate the thrust assembly 106.

[0576] Also shown in FIG. 13 is an axial trigger arrangement, generally denoted 128. The axial trigger arrangement 128 is configured to selectively axially lock the mandrel 14 and the housing 12. In a first configuration (as shown in FIG. 13), the axial trigger arrangement 128 is configured to axially lock the mandrel 14 and the housing 12. In a second configuration, the axial trigger arrangement 128 is configured to permit axial movement between the mandrel 14 and the housing 12.

[0577] As shown in FIG. 13, the axial trigger arrangement 128 comprises a locking profile 130. The locking profile 130 is provided on the mandrel 14. In the illustrated tool T, the locking profile 130 comprises or take the form of a castellated profile.

[0578] The axial trigger arrangement 128 comprises locking keys 132 comprising a castellated profile 134 on their inner circumferential surface which is configured to engage the locking profile 130 on the mandrel 14.

[0579] The locking keys 132 are reconfigurable between a radially retracted configuration as shown in FIG. 13 and a radially extended configuration.

[0580] The axial trigger arrangement 128 further comprises a taper lock 136 formed by lock bowl 138 defining a tapered surface 140 configured to engage corresponding tapered surfaces 142 on the locking keys 132.

[0581] In the illustrated tool T, the axial trigger arrangement 128 further comprises a spring arrangement 144 which in the illustrated jarring apparatus 10 takes the form of a Belleville spring stack.

[0582] The spring arrangement 144 is coupled to or configured to engage the lock bowl 138 to urge the locking keys 132 towards their retracted configuration. In use, the spring arrangement 144 and taper lock 136 define a retainer of the axial trigger arrangement 128.

[0583] In the illustrated tool T, the locking keys 132 are also held in the radially retracted configuration by a resilient element 146 in the form of an elastic member.

[0584] The axial trigger arrangement 128 is configured to move the locking keys 132 to the extended configuration in response to an axial pull or tensile force applied to the mandrel 14 or a push, compressive or applied weight force. More particularly, the axial trigger arrangement is configured to move the one or more locking keys 132 to the extended configuration in response to an axial pull or tensile force or axial push, compressive or applied weight above a predetermined threshold force, in particular the spring force of the spring arrangement 144 and where applicable the force exerted by the resilient element 146. The application of a pull or tensile force facilitates an axial up jar operation and/or rotary jarring operation. The application of a push, compressive or applied weight force facilitates an axial down jar operation.

[0585] As shown in FIG. 13, and referring now also to FIGS. 14 and 15 of the accompanying drawings, the tool T further comprises a valve arrangement, generally denoted 148, configured to provide selective fluid communication through the axial throughbore 38 of the jarring apparatus 10.

[0586] In use, the valve arrangement 148 is configurable between a first, open, configuration which permits full bore access through the axial throughbore 38 of the jarring apparatus and an obturated configuration in which access through the jarring apparatus 10 is restricted, such restriction providing a back pressure for use in operation of the jarring apparatus 10 as will be described further below.

[0587] The valve arrangement 148 comprises a valve member 150, which in the illustrated apparatus 10 takes the form of a ball having throughbore 151, and an actuator sleeve 152. The valve member 150 is captivated between an upper valve seat 154 and a lower valve seat 156. The valve arrangement 148 comprises a valve operator arrangement comprising operator members 158. As shown most clearly in FIG. 15, each operator member 158 comprises a tab 160 which seats in a corresponding recess 162 in the actuator sleeve 1520 and a pin 163 which engages an offset slot 164 in the valve member 150.

[0588] In use, axial movement of the actuator sleeve 152 translates the operator members 158 to pivot the valve member 150 and thereby reconfigure the valve arrangement 148 from the open configuration to the obturated configuration.

[0589] As shown, seat plates 166 are provided, the seat plates 166 having tabs 168 for engaging corresponding recesses 170 in the upper and lower valve seats 154,156. In the illustrated tool T, rotation of the valve member 150 is limited to a ¼ turn by movement limiters 172 provided on the seat plates 166.

[0590] The valve arrangement 148 comprises an indexer mechanism, generally denoted 174, which in the illustrated tool T takes the form of a dog indexer as will be described below.

[0591] An upper portion of the actuator sleeve 152 has slots 176, through which are disposed a number of dogs 178. As shown in FIG. 13, the dogs 178 are disposed on the mandrel 14 such that axial movement of the mandrel 14 de-supports the dogs 178 and permits axial movement of the actuator sleeve 152.

[0592] As shown in FIG. 13, upper dogs 180 are disposed on a recess 182 in the outer circumferential surface of the mandrel 14. In use, relative axial movement of the mandrel 14 and the housing 12 aligns the dogs 180 with corresponding recesses 184 formed in the inner circumferential surface of the housing 12, allowing the dogs 180 to move radially outwards and thereby stop further axial movement of the actuator sleeve 152.

[0593] A ramp profile 188 is provided on the outer circumferential surface of the mandrel 14, such that relative axial movement of the mandrel 14 and the housing 12 in the opposing direction will release the upper dogs 180 from the recesses 184 and push the dogs 178 radially outwards, so that the valve arrangement 148 is returned to the first, open, configuration. The valve arrangement 148 may thus be opened and closed repeatedly as required, by relative axial movement of the mandrel 14 and the housing 12.

[0594] As shown, the valve member 150 has an orifice 190, which in the illustrated jarring apparatus 10 is provided as an insert. When the valve member 150 defines the obturated configuration, the orifice 190 is aligned with the axial throughbore 38. Flow through the orifice 190 generates a back pressure. The provision of the orifice 190 also means that even when the valve arrangement 148 defines the obturated configuration, some fluid communication through the jarring apparatus 10 is nevertheless provided. Beneficially, this permits the jarring apparatus 10 to function without complete closure of the axial flow passage 38 and, for example, permits circulation of fluid below the jarring apparatus 10 and/or transmission of pressure forces which may be required to operate downhole tools.

[0595] As shown in FIG. 13, the jarring apparatus 10 further comprises a bottom sub 192. The bottom sub 192 is generally tubular in construction having an axial throughbore 194 extending therethrough. A lower end portion of the top sub 192 defines a connector 196 for coupling the jarring apparatus 10 to another component of the tool string S. In the illustrated jarring apparatus 10, the connector 196 takes the form of a male connector, more specifically a threaded pin connector. A lower end portion of the bottom sub 192 defines a male profile 186 configured to engage the lower end of the housing 12. In the illustrated jarring apparatus 10, the bottom sub 192 further comprises stabiliser blades 198 for offsetting the jarring apparatus 10 from the borehole.

[0596] FIG. 16 of the accompanying drawings shows the tool T with the jarring apparatus 10 in a primed configuration suitable for performing a jarring operation.

[0597] As shown in FIG. 16, the spline connection 122 has been disengaged, with relative axial movement of the mandrel 14 and the housing 12 bringing the thrust assembly 106 into engagement. In the configuration shown in FIG. 16, the seal arrangement 124 is unseated such that fluid communication is permitted between the axial throughbore 38 and the thrust assembly 106 via the ports 126, so as to facilitate cooling and/or lubrication of the thrust assembly 106.

[0598] In this primed configuration, the upper valve inlet 28 is in the open configuration, the upper valve exhaust 30 is in the closed configuration, the lower valve inlet 32 is in the closed configuration and the lower valve exhaust 34 is in the open configuration. The axial trigger arrangement 128 has been released.

[0599] Referring also to FIG. 17, which shows a perspective view of the valve arrangement 126, relative axial movement between the mandrel 14 and the housing 12 has de-supported the dogs 178 which have moved radially inwards and engaged the upper dogs 180 with their recesses 184, permitting axial movement of the actuator sleeve 130 to reconfigure the valve member 150 to the obturated configuration with the orifice 190 aligned with the axial throughbore 38.

[0600] As can be seen from FIG. 17, the actuator sleeve 152 can move relative to the valve member 150 but the valve member 150 remains captivated between the valve seats 154,156.

[0601] FIG. 18 of the accompanying drawings shows the jarring apparatus 10 configured to generate a linear down-jar force. As shown in FIG. 18, the upper valve inlet 28 is in the closed configuration, the upper valve exhaust 30 is in the open configuration, the lower valve inlet 32 is in the closed configuration and the lower valve exhaust 34 is in the open configuration. The valve arrangement 148 is in the open configuration. The impact surfaces 118,120 are engaged.

[0602] It will be understood that various modifications may be made without departing from the scope of the invention as defined in the claims.

[0603] For example, FIGS. 19 to 23 of the accompanying drawings illustrate an alternative rotary valve assembly 1024. Similar components of the rotary valve assembly 1024 to the rotary valve assembly 24 are indicated with like reference signs incremented by 1000. While components of the rotary valve assembly 1024 are designated using reference signs corresponding to those of the upper rotary valve assembly 24, it will be recognised that the rotary valve assembly 1024 may be utilised in mirror image to alternatively or additionally form a lower rotary valve assembly corresponding to the lower rotary valve assembly 26.

[0604] As shown in FIG. 19, the rotary valve assembly 1024 comprises valve inlet 1028 formed in mandrel 1014, valve exhaust 1030 formed in housing 1012, and annular piston chamber 1020.

[0605] Whereas the rotary valve assembly 24 comprises separate rotary valve members in the form of inlet selector sleeve and exhaust selector sleeves, in the rotary valve assembly 1024 a single rotary valve member 1044 is provided. The rotary valve member 1044 takes the form of a selector sleeve. The rotary valve member 1044 is operatively associated with the valve inlet 1028 and the valve exhaust 1030.

[0606] In use, during one phase of relative rotation (as shown in FIG. 22), the valve inlet 1028 defines an open configuration in which pressure communication with the piston chamber 1020 is permitted by the rotary valve member 1044 and pressure communication with the valve exhaust 1030 is prevented by the rotary valve member 1044. In another phase (as shown in FIG. 23), the valve inlet 1028 defines the closed configuration in which pressure communication with the piston chamber 1020 is prevented, substantially prevented or obturated by the rotary valve member 1044 and pressure communication with the valve exhaust 1030 is permitted by the rotary valve member 1044.

[0607] As described above, it will be understood that various modifications may be made without departing from the scope of the invention as defined in the claims.

[0608] FIG. 24 of the accompanying drawings illustrates part of an alternative jarring apparatus 2010.

[0609] As shown in FIG. 24, rotary valve arrangement 2022 comprises a first, upper, valve assembly, generally denoted 2024, similar to valve assembly 24 described above but the second biasing arrangement provided by the second, lower, valve assembly 26 has been replaced by an alternative biasing arrangement as described below.

[0610] The upper rotary valve assembly 2024 comprises a valve inlet 2028 for communicating with a pressure region P and a valve exhaust 2030 for communicating with an exhaust region E.

[0611] The upper rotary valve assembly 2024 is operated by relative rotation between mandrel 2014 and housing 2012 to be cyclically reconfigured between: a pressure configuration in which the piston chamber 2020 is in pressure communication with the valve inlet 2028 and isolated from the valve exhaust 2030 to permit the jarring piston 2016 to move in the first axial direction A (to the right as shown in FIG. 24) in accordance with the piston chamber 2020 being pressurised via the valve inlet 2028; and an exhaust configuration in which the piston chamber 2020 is isolated from the valve inlet 2028 and in pressure communication with the valve exhaust 2030 to permit the piston chamber 2020 to be depressurised and the jarring piston 2016 to move in the second axial direction B (to the left as shown in FIG. 24). Movement of the jarring piston 2016 and the coupled hammer 3082 generates a jarring force within the jarring apparatus 2010.

[0612] As described above, the second, lower, valve assembly 26 has been replaced by an alternative biasing arrangement. In the illustrated jarring apparatus 2010, the biasing force applied to the jarring piston 2016 is provided by a spring arrangement 2202.

[0613] As shown in FIG. 24, exhaust ports 2204 are provided through the wall of the housing 2012 to prevent hydraulic locking.

[0614] In use, pressure moves the hammer 2082 against the bias of the spring arrangement 2202. When the valve exhaust 2030 is opened, the hammer 2082 is driven by the spring arrangement 2202 into engagement with the anvil 2092, to thereby generate the jarring forces within the jarring apparatus 2010.

[0615] FIG. 25 of the accompanying drawings illustrates part of an alternative jarring apparatus 3010.

[0616] As shown in FIG. 25, the rotary valve arrangement 3022 comprises a lower valve assembly, generally denoted 3026, similar to the lower valve assembly 26.

[0617] The rotary valve assembly 3026 comprises a valve inlet 3032 for communicating with a pressure region P and a valve exhaust 3034 for communicating with an exhaust region E.

[0618] The rotary valve assembly 3026 is operated by relative rotation between mandrel 3014 and housing 3012 to be cyclically reconfigured between: a pressure configuration in which the piston chamber 3020 is in pressure communication with the valve inlet 3032 and isolated from the valve exhaust 3034 to permit the jarring piston 3016 to move in the second axial direction B (to the left as shown in FIG. 25) in accordance with the piston chamber 3020 being pressurised via the valve inlet 3032; and an exhaust configuration in which the piston chamber 3020 is isolated from the valve inlet 3032 and in pressure communication with the valve exhaust 3034 to permit the piston chamber 3020 to be depressurised and the jarring piston 3016 to move in the first axial direction A (to the right as shown in FIG. 25). Movement of the jarring piston 3016 and the coupled hammer 3082 generates a jarring force within the jarring apparatus 3010.

[0619] In the illustrated jarring apparatus 3010, the second biasing force applied to the jarring piston 3016 is provided by a spring arrangement 3202 in a similar manner to the apparatus 2010.

[0620] As shown in FIG. 25, exhaust ports 3204 are provided through the wall of the housing 3012 to prevent hydraulic locking.

[0621] In use, pressure lifts the hammer 3082 against the bias of the spring arrangement 3202 to cause an upwards jarring force. When the valve inlet 3032 is closed and the valve exhaust 3034 is opened the hammer 3082 is returned by the spring arrangement 3202 ready for another upward jar in the next cycle.

[0622] FIG. 26 of the accompanying drawings illustrates a tool T2 comprising an alternative jarring apparatus 4010, in a neutral configuration. The jarring apparatus 4010 is configured to facilitate rotary jarring with applied tension (“overpull”) or applied weight using the same apparatus.

[0623] The jarring apparatus 4010 is similar to the apparatus 10 described above and like components are represented by like reference signs incremented by 4000.

[0624] As shown in FIG. 26, the apparatus 4010 comprises housing 4012, mandrel 4014 and inlet selector 4052. In the illustrated apparatus 4010, the mandrel 4014 comprises two axially spaced valve inlets 4042a, 4042b.

[0625] In use, relative axial movement in a downwards direction (to the right as shown in FIG. 26) is used to align the valve inlet 4042a with ports 4048 of the inlet selector 4052.

[0626] In use, relative axial movement in an upwards direction (to the left as shown in FIG. 26) is used to align the valve inlet 4042b with ports 4048 of the inlet selector 4052.

[0627] As shown in FIG. 26, the tool T2 further comprises two swivels in the form of upper swivel 4106U and lower swivel 4106L. The upper and lower swivels 4106U,4106L are substantially identical to the swivel 106 described above, with lower swivel 4106L being oriented in the opposite direction. As will be recognised, the swivels 4106U,4106L facilitate transmission of axial loading between the mandrel 4014 and the housing 4012, thus diverting such loading from other components within the apparatus 4010, which axial loading in this example may be in either axial direction dependent on whether the apparatus 4010 is subject to tensile/pull forces or weight/push forces.

[0628] As shown in FIG. 26, the spline 4022 have also been modified to permit disengagement when weight/push forces are applied.

[0629] As described above, further modifications may be made without departing from the scope of the claims.

[0630] For example, it will be understood that the apparatus 4010 may be readily modified to facilitate jarring with applied weight/push forces only by removing or blocking the ports 4042b.

[0631] For example, FIGS. 27 and 28 of the accompanying drawings diagrammatically show part of an alternative jarring apparatus 5010. FIG. 27 shows the jarring apparatus 5010 in a first phase of rotation in which the apparatus 5010 permits fluid communication between axial throughbore 5038 and piston chamber 5020 via valve inlet 5028 but prevents or restricts fluid communication between axial throughbore 5038 and the valve exhaust 5030. FIG. 28 shows the jarring apparatus 5010 in a second phase of rotation in which the apparatus 5010 prevents or restricts fluid communication between axial throughbore 5038 and piston chamber 5020 via valve inlet 5028 but permits fluid communication between piston chamber 5020 and the valve exhaust 5030.

[0632] While in examples above, the mandrel is at least partially mounted within the housing, as shown in FIGS. 27 and 28 in the apparatus 5010 mandrel 5014 and housing 5012 are disposed co-axially. In the illustrated apparatus 5010, the mandrel 5014 is disposed above the housing 5012, although it will be understood that in other examples the housing could be disposed above the mandrel.

[0633] As described above, various modifications may be made without departing from the scope of the appended claims.

[0634] For example, and referring now to FIGS. 29 to 32 of the accompanying drawings there is shown an alternative reciprocating drive apparatus 6010 in the form of a hammer apparatus.

[0635] In use, the apparatus 6010 is configured to generate an applied axial force output for transmission to a connected component, assembly or tool.

[0636] As shown, the apparatus 6010 comprises a housing 6012 and a mandrel 6014, the mandrel 6014 and the housing 6012 configurable to be rotated relative to each other. It will be understood that reference to relative rotation between the housing 6012 and the mandrel 6014 may include the apparatus 6010 being configured such that: the mandrel 6014 rotates while the housing 6012 is stationary; such that the housing 6012 rotates while the mandrel 6014 is stationary; or such that the mandrel 6014 and the housing 6012 both rotate. Beneficially, this facilitates flexibility in that hammering operations may be carried out in a number of different operational scenarios.

[0637] The apparatus 6010 further comprises a reciprocating piston 6016 mounted within piston housing 6018 so as to define a first piston chamber 6020a (shown most clearly in FIG. 31) and a second piston chamber 6020b. The piston 6016 is moveable within the first and second piston chambers 6020a,6020b in reverse first and second axial directions A,B.

[0638] The apparatus 6010 further comprises a rotary valve assembly 6024 comprises a valve inlet 6028 for communicating with a pressure region P and a valve exhaust 6030 for communicating with an exhaust region E.

[0639] The rotary valve assembly 6024 comprises a rotary valve member 6044 operatively associated with the valve inlet 6028. In the illustrated apparatus 6010, the rotary valve member 6044 takes the form of an inlet selector sleeve. The rotary valve member 6044 and the valve inlet 6028 are configured for relative rotation to each other such that rotation causes the rotary valve member 6044 to selectively block or obturate the valve inlet 6028. That is, during one phase of relative rotation, the valve inlet 6028 defines an open configuration in which pressure communication with the piston chamber 6020a is permitted and in another phase the valve inlet 6028 defines the closed configuration in which pressure communication with the piston chamber 6020a is prevented, substantially prevented or obturated.

[0640] In the illustrated apparatus 6010, the rotary valve member 6044 is fixed to the housing 6012 via thread connection 6206, such that relative rotation between the mandrel 6014 and the housing 6012 reconfigures the valve assembly 6024 as described further below. However, it will be understood that the rotary valve member 6044 may be coupled to the housing by any suitable means.

[0641] In the illustrated apparatus 6010, the housing 6012 comprises or takes the form of a sleeve that, in use, acts as a non-rotating element (or as a relatively lower rotational speed element compared to the mandrel 6014).

[0642] In use, the mandrel 6014—which by virtue of threaded box connection 6208 is coupled to and rotates with a rotating string (not shown) of which the apparatus 6010 forms a part—rotates while the housing 6012—which by virtue of its engagement with borehole H—does not rotate or rotates at a lower rotational speed than the mandrel 6014. As the rotary valve member 6044 is fixed to the housing 6012 via thread connection 6206, relative rotation is also provided between the mandrel 6014 and the rotary valve member 6044.

[0643] The valve assembly 6024 is operated by relative rotation between the mandrel 6014 and the housing 6012 and the rotary valve member 6044 to be cyclically reconfigured between: a pressure configuration in which the piston chamber 6020a is in pressure communication with the valve inlet 6028 and isolated from the valve exhaust 6030 to permit the piston 6016 to move in the first axial direction A in accordance with the piston chamber 6020a being pressurised via the valve inlet 6028; and an exhaust configuration in which the piston chamber 6020a is isolated from the valve inlet 6028 and in pressure communication with the valve exhaust 6030 to permit the piston chamber 6020a to be depressurised and the piston 6016 to move in the second axial direction B.

[0644] FIGS. 29 and 30 show the apparatus 6010 in a first phase of rotation corresponding to the exhaust configuration in which the apparatus 6010 prevents or restricts fluid communication between axial throughbore 6038 of the apparatus 6010 and piston chamber 6020a via valve inlet 6028 but permits fluid communication between piston chamber 6020a and the valve exhaust 6030.

[0645] FIGS. 31 and 32 show the apparatus 6010 in a second phase of rotation corresponding to the pressure configuration in which the apparatus 6010 permits fluid communication between axial throughbore 6038 and piston chamber 6020a via valve inlet 6028 but prevents or restricts fluid communication between axial throughbore 6038 and the valve exhaust 6030.

[0646] As shown in FIGS. 31 and 32, when the apparatus 6010 defines the pressure configuration fluid pressure acting on the piston 6016 urges the piston 6016 axially relative to piston housing 6018 against the bias of spring arrangement 6202. As the piston 6016 translates relative to the piston housing 6018, fluid in piston chamber 6020b is displaced through exhaust ports 6204, thereby preventing a hydraulic lock.

[0647] Referring again to FIGS. 29 and 31, it can be seen that the piston 6016 is coupled to a hammer 6084 by a coupling arrangement 6210, which in the illustrated apparatus 6010 takes the form of a thread connection. As such, axial movement of the piston 6016 also moves the hammer 6084 axially.

[0648] In use, axial movement of the hammer 6084 in the first direction A by the piston 6016 engages a distal end portion of the hammer 6084 with an output shaft, generally denoted 6212, generating an impact force.

[0649] In the illustrated apparatus 6010, the output shaft 6212 comprises a first component 6212a forming an anvil, chisel or receiver for receiving the impact force from the hammer 6084 and a second component 6212b forming an end effector of the apparatus 6010. However, it will be understood that the output shaft 6212 may alternatively comprise or take the form of a unitary member. As shown in FIGS. 29 and 31, a distal end portion of the first component 6212a is coupled to the second component 6212b by a coupling arrangement 6214, which in the illustrated apparatus 6010 takes the form of a thread connection. The output shaft 6212 (in particular the second component 6212b) has a coupling arrangement 6216, which in the illustrated apparatus 6010 takes the form of a thread connection formed on an outer surface of the output shaft 6212. The coupling arrangement 6216 may be utilised to transmit the applied axial force output from the apparatus 6010 to a connected component, assembly or tool.

[0650] In the illustrated apparatus 6010, a proximal end portion of the piston housing 6018 is coupled to the mandrel 6014 by a coupling arrangement 6220, which in the illustrated apparatus 6010 takes the form of a thread connection. As such, rotational movement and/or applied torque from the mandrel 6014 is transmitted to the piston housing 6018. A distal end portion of the piston housing 6018 is coupled to a bottom sub 6222 of the apparatus 6010 by a coupling arrangement 6224, which in the illustrated apparatus 6010 takes the form of a thread connection. The bottom sub 6222 comprises a further coupling arrangement 6226, which in the illustrated apparatus 6010 takes the form of a thread connection formed on an outer surface of the bottom sub 6222. The coupling arrangement 6222 facilitates connection and transmission of rotational movement and/or applied torque to downhole components of the tool string, such as the housing of a connected component or tool, where required.

[0651] As shown in FIGS. 29 and 31, a key 6228 is provided and functions to transmit torque from the mandrel 6014 (via the piston housing 6018) to the output shaft 6212.

[0652] As described above, the apparatus 6010 may be utilised to generate an applied axial force output for transmission to a connected component, assembly or tool.

[0653] Referring now also to FIGS. 33 and 34 of the accompanying drawings, there is shown a downhole tool T3 comprising the apparatus 6010 and a bit 6230, which in the illustrated tool T3 takes the form of a drill bit.

[0654] In use, the downhole tool T3 takes the form of a percussion drilling tool.

[0655] As shown in FIGS. 33 and 34, the bit 6230 comprises ports 6232 which communicate with the throughbore 6038, facilitating amongst other things lubrication of the bit 6230 in use and fluid circulation to surface.

[0656] As shown in FIG. 34, the output shaft 6212 of the apparatus 6010 is coupled to the bit 6230 via the coupling arrangement 6216 such that the applied axial force output generated by the apparatus 6010 is transmitted to the bit 6230 while at the same time the rotational movement and/or applied torque from the mandrel 6014 is also transmitted to the bit 6230 via the key 6228 to drive rotation of the bit 6230 and drill the borehole H. In the downhole tool T3, the bit 6230 forms the distal leading end of a tool string, and so an end cap 6234 is located on coupling arrangement 6226.

[0657] A downhole tool T4 comprising an alternative hammer apparatus 7010 and a radial hammer assembly 7236 is shown in FIGS. 35 to 38 of the accompanying drawings.

[0658] As shown in FIGS. 35 and 37, the apparatus 7010 comprises a housing 7012 and a mandrel 7014, the mandrel 7014 and the housing 7012 configurable to be rotated relative to each other. It will be understood that reference to relative rotation between the housing 7012 and the mandrel 7014 may include the apparatus 7010 being configured such that: the mandrel 7014 rotates while the housing 7012 is stationary; such that the housing 7012 rotates while the mandrel 7014 is stationary; or such that the mandrel 7014 and the housing 7012 both rotate. Beneficially, this facilitates flexibility in that hammering operations may be carried out in a number of different operational scenarios.

[0659] The apparatus 7010 further comprises a reciprocating piston 7016 mounted within piston housing 7018 so as to define first and second piston chambers 7020a,7020b. The piston 7016 is moveable within the first and second piston chambers 7020a,7020b in reverse first and second axial directions A,B.

[0660] The apparatus 7010 further comprises a rotary valve assembly 7024 comprises a valve inlet 7028 for communicating with a pressure region P and a valve exhaust 7030 for communicating with an exhaust region E.

[0661] The rotary valve assembly 7024 comprises a rotary valve member 7044 operatively associated with the valve inlet 7028. In the illustrated apparatus 7010, the rotary valve member 7044 takes the form of an inlet selector sleeve. The rotary valve member 7044 and the valve inlet 7028 are configured for relative rotation to each other such that rotation causes the rotary valve member 7044 to selectively block or obturate the valve inlet 7028. That is, during one phase of relative rotation, the valve inlet 7028 defines an open configuration in which pressure communication with the piston chamber 7020a is permitted and in another phase the valve inlet 7028 defines the closed configuration in which pressure communication with the piston chamber 7020a is prevented, substantially prevented or obturated.

[0662] In the illustrated apparatus 7010, the rotary valve member 7044 is fixed to the housing 7012 via thread connection 7206, such that relative rotation between the mandrel 7014 and the housing 7012 reconfigures the valve assembly 7024 as described further below.

[0663] In the illustrated apparatus 7010, the housing 7012 comprises or takes the form of a sleeve that acts as a non-rotating element (or as a relatively lower rotational speed element compared to the mandrel 6014).

[0664] In use, the mandrel 7014—which by virtue of threaded box connection 7208 is coupled to and rotates with a rotating string (not shown) of which the apparatus 7010 forms a part—rotates while the housing 7012—which by virtue of its engagement with borehole H (which in this application takes the form of a bore-lining tubing such as casing)—does not rotate or rotates at a lower rotational speed than the mandrel 7014. As the rotary valve member 7044 is fixed to the housing 7012 via thread connection 7206, relative rotation is also provided between the mandrel 7014 and the rotary valve member 7044.

[0665] The valve assembly 7024 is operated by relative rotation between the mandrel 7014 and the housing 7012 and the rotary valve member 7044 to be cyclically reconfigured between: a pressure configuration in which the piston chamber 7020a is in pressure communication with the valve inlet 7028 and isolated from the valve exhaust 7030 to permit the piston 7016 to move in the first axial direction A in accordance with the piston chamber 7020a being pressurised via the valve inlet 7028; and an exhaust configuration in which the piston chamber 7020a is isolated from the valve inlet 7028 and in pressure communication with the valve exhaust 7030 to permit the piston chamber 7020a to be depressurised and the piston 7016 to move in the second axial direction B.

[0666] FIGS. 35 and 36 show the apparatus 7010 in a first phase of rotation corresponding to the exhaust configuration in which the apparatus 7010 prevents or restricts fluid communication between axial throughbore 7038 of the apparatus 7010 and piston chamber 7020a via valve inlet 7028 but permits fluid communication between piston chamber 7020a and the valve exhaust 7030.

[0667] FIGS. 37 and 38 show the apparatus 7010 in a second phase of rotation corresponding to the pressure configuration in which the apparatus 7010 permits fluid communication between axial throughbore 7038 and piston chamber 7020a via valve inlet 7028 but prevents or restricts fluid communication between axial throughbore 7038 and the valve exhaust 7030.

[0668] As shown, when the apparatus 7010 defines the pressure configuration fluid pressure acting on the piston 7016 urges the piston 7016 axially relative to piston housing 7018 against the bias of spring arrangement 7202. Fluid in piston chamber 7020b is displaced through exhaust ports 7204, thereby preventing a hydraulic lock.

[0669] Referring again to FIGS. 35 and 37, it can be seen that the piston 7016 is coupled to a hammer 7084 by a coupling arrangement 7210, which in the illustrated apparatus 7010 takes the form of a thread connection. As such, axial movement of the piston 7016 also moves the hammer 7084 axially.

[0670] In the downhole tool T4, a distal end portion of the hammer 7084 is coupled to an output shaft 7212 of the apparatus 7010 by a coupling arrangement 7214, which in the illustrated apparatus 7010 takes the form of a thread connection. The output shaft 7212 has a coupling arrangement 7216, which in the illustrated apparatus 7010 takes the form of a thread connection formed on an outer surface of the output shaft 7212. The coupling arrangement 7216 may be utilised to transmit the applied axial force output from the apparatus 7010 to the radial hammer assembly 7236.

[0671] As shown in FIGS. 35 and 37, a proximal end portion of the piston housing 7018 is coupled to the mandrel 7014 by a coupling arrangement 7220, which in the illustrated apparatus 7010 takes the form of a thread connection. As such, rotational movement and/or applied torque from the mandrel 7014 is transmitted to the piston housing 7018. A distal end portion of the piston housing 7018 is coupled to a bottom sub 7222 of the apparatus 7010 by a coupling arrangement 7224, which in the illustrated apparatus 7010 takes the form of a thread connection. The bottom sub 7222 comprises a further coupling arrangement 7226, which in the illustrated apparatus 7010 takes the form of a thread connection formed on an outer surface of the bottom sub 7222. The coupling arrangement 7222 facilitates connection to a housing 7238 of the radial hammer assembly 7236.

[0672] In the illustrated apparatus 7010, a key 7228 is provided and functions to transmit torque from the mandrel 7014 (via the piston housing 7018 and the hammer 7084) to the output shaft 7212.

[0673] As described above, the apparatus 7010 may be utilised to generate an applied axial force output for transmission to the radial hammer assembly 7236.

[0674] As shown, the radial hammer assembly 7236 comprises a tapered bowl 7240 having a tapered outer surface 7242 and a plurality of circumferentially arranged and spaced hammer members 7244 each having a tapered inner surface 7246. In the illustrated tool T4, the hammer members 7244 take the form of dogs.

[0675] The radial hammer assembly 7236 is reconfigurable between a first configuration in which the hammer members 7244 define a radially retracted position within the apparatus 7010 and a second configuration in which the hammer members 7244 define a radially extended position which, in use, engages the borehole H.

[0676] In the illustrated tool T4, ports 7248 are provided in the bowl 7240 which communicate with the throughbore 7038, facilitating amongst other things lubrication of the radial hammer assembly 7236 in use and fluid circulation to surface.

[0677] As shown in FIGS. 35 and 37, the bowl 7240 is coupled to the output shaft 7212, such that the axial movement of the output shaft 7212 by the mandrel 7014 urges the bowl 7240 into engagement with the hammer members 7244, so as to reconfigure the radial hammer assembly 7236 from the first configuration to the second configuration.

[0678] The output force generated by the apparatus 7010 is also transmitted to the bowl 7240 which, by virtue of the engagement of the tapered surfaces 7242,7246 transmits the applied force output to the hammer members 7244.

[0679] FIGS. 39 to 46 of the accompanying drawings show an alternative reciprocating drive apparatus 8010 in the form of an axial hammer apparatus.

[0680] In use, the apparatus 8010 is configured to generate an applied axial force output for transmission to a connected component, assembly or tool.

[0681] The apparatus 8010 is similar to the apparatus 6010,7010 described above and like components are represented by like reference signs incremented by 8000. Whereas the apparatus 6010,7010 are configured to transmit applied axial forces and torque, the apparatus 8010 is configured to transmit axial forces only.

[0682] As shown, the apparatus 8010 comprises a housing 8012 and a mandrel 8014, the mandrel 8014 and the housing 8012 configurable to be rotated relative to each other. It will be understood that reference to relative rotation between the housing 8012 and the mandrel 8014 may include the apparatus 8010 being configured such that: the mandrel 8014 rotates while the housing 8012 is stationary; such that the housing 8012 rotates while the mandrel 8014 is stationary; or such that the mandrel 8014 and the housing 8012 both rotate. Beneficially, this facilitates flexibility in that hammering operations may be carried out in a number of different operational scenarios.

[0683] The apparatus 8010 further comprises a reciprocating piston 8016 mounted within piston housing 8018 so as to define a first piston chamber 8020a (shown most clearly in FIG. 43) and a second piston chamber 8020b. The piston 8016 is moveable within the first and second piston chambers 8020a,8020b in reverse first and second axial directions A,B.

[0684] The apparatus 8010 further comprises a rotary valve assembly 8024 comprises a valve inlet 8028 for communicating with a pressure region P and a valve exhaust 8030 for communicating with an exhaust region E.

[0685] The rotary valve assembly 8024 comprises a rotary valve member 8044 operatively associated with the valve inlet 8028. In the illustrated apparatus 8010, the rotary valve member 8044 takes the form of an inlet selector sleeve. The rotary valve member 8044 and the valve inlet 8028 are configured for relative rotation to each other such that rotation causes the rotary valve member 8044 to selectively block or obturate the valve inlet 8028. That is, during one phase of relative rotation, the valve inlet 8028 defines an open configuration in which pressure communication with the piston chamber 8020a is permitted and in another phase the valve inlet 8028 defines the closed configuration in which pressure communication with the piston chamber 8020a is prevented, substantially prevented or obturated.

[0686] The rotary valve member 8044 is supported within the apparatus 8010 by bearings 8248.

[0687] FIGS. 39 to 42 show the apparatus 8010 in a first phase of rotation corresponding to the pressure configuration in which the apparatus 8010 permits fluid communication between axial throughbore 8038 and piston chamber 8020a via valve inlet 8028 but prevents or restricts fluid communication between axial throughbore 8038 and the valve exhaust 8030.

[0688] In FIG. 39, the output shaft 8212 is shown in an extended position. In FIG. 41, the output shaft 8212 is shown in a retracted position, for example after weight has been applied.

[0689] As shown, when the apparatus 8010 defines the pressure configuration fluid pressure acting on the piston 8016 urges the piston 8016 axially relative to piston housing 8018 against the bias of spring arrangement 8202. Fluid in piston chamber 8020b is displaced through exhaust ports 8204, thereby preventing a hydraulic lock.

[0690] It can be seen that the piston 8016 is coupled to a hammer 8084 by a coupling arrangement 8210, which in the illustrated apparatus 8010 takes the form of a thread connection. As such, axial movement of the piston 8016 also moves the hammer 8084 axially.

[0691] In use, axial movement of the hammer 8084 by the piston 8016 engages a distal end portion of the hammer 8084 with an output shaft, generally denoted 8212, generating an impact force.

[0692] In the illustrated apparatus 8010, the output shaft 8212 comprises a first component 8212a forming an anvil, chisel or receiver for receiving the impact force from the hammer 8084 and a second component 6212b forming an end effector of the apparatus 8010. However, it will be understood that the output shaft 8212 may alternatively comprise or take the form of a unitary member. As shown, a distal end portion of the first component 8212a is coupled to the second component 8212b by a coupling arrangement 8214, which in the illustrated apparatus 8010 takes the form of a thread connection. The output shaft 8212 (in particular the second component 8212b) has a coupling arrangement 8216, which in the illustrated apparatus 8010 takes the form of a thread connection formed on an outer surface of the output shaft 8212. The coupling arrangement 8216 may be utilised to transmit the applied axial force output from the apparatus 8010 to a connected component, assembly or tool.

[0693] As shown in FIGS. 39 and 41, a proximal end portion of the piston housing 8018 is coupled to the housing 8012 by a coupling arrangement 8220, which in the illustrated apparatus 8010 takes the form of a thread connection. A distal end portion of the piston housing 8018 is coupled to a bottom sub 8222 of the apparatus 8010 by a coupling arrangement 8224, which in the illustrated apparatus 8010 takes the form of a thread connection. The bottom sub 8222 comprises a further coupling arrangement 8226, which in the illustrated apparatus 8010 takes the form of a thread connection formed on an outer surface of the bottom sub 8222.

[0694] As shown in FIGS. 39 and 41, a key 8228 is provided and functions to rotationally lock the output shaft 8212 to the piston housing 8018. While in the illustrated apparatus 8010 a key 8228 is provided, it will be understood that in other forms of the apparatus the key 8228 may be omitted.

[0695] As described above, the apparatus 8010 may be utilised to generate an applied axial force output for transmission to a connected component, assembly or tool.

[0696] FIGS. 45 and 46 show the apparatus 8010 in a second phase of rotation corresponding to the exhaust configuration in which the apparatus 8010 prevents fluid communication between axial throughbore 8038 and piston chamber 8020a via valve inlet 8028 but permits fluid communication between axial throughbore 8038 and the valve exhaust 8030.

[0697] As shown, when the apparatus 8010 defines the exhaust configuration the spring arrangement 8202 urges the piston 8016 axially relative to piston housing 8018 in the direction B (to the left as shown in FIG. 45).

[0698] As described above, various modifications may be made without departing from the scope of the claims.

[0699] For example, referring now to FIGS. 47 to 50 of the accompanying drawings there is shown an alternative reciprocating drive apparatus 9010 in the form of an axial reciprocator apparatus.

[0700] In use, the apparatus 9010 is configured to generate an applied axial force output for transmission to a connected component or assembly of the apparatus 9010 or other connected tool.

[0701] As shown, the apparatus 9010 comprises a housing 9012 and a mandrel 9014, the mandrel 9014 and the housing 9012 configurable to be rotated relative to each other. It will be understood that reference to relative rotation between the housing 9012 and the mandrel 9014 may include the apparatus 9010 being configured such that: the mandrel 9014 rotates while the housing 9012 is stationary; such that the housing 9012 rotates while the mandrel 9014 is stationary; or such that the mandrel 9014 and the housing 9012 both rotate.

[0702] The apparatus 9010 further comprises a reciprocating piston 9016 mounted within piston housing 9018 so as to define a first piston chamber 9020a (shown most clearly in FIG. 49) and a second piston chamber 9020b. The piston 9016 is moveable within the first and second piston chambers 9020a,9020b in reverse first and second axial directions A, B.

[0703] The apparatus 9010 further comprises a rotary valve assembly 9024 comprises a valve inlet 9028 for communicating with a pressure region P and a valve exhaust 9030 for communicating with an exhaust region E.

[0704] The rotary valve assembly 9024 comprises a rotary valve member 9044 operatively associated with the valve inlet 9028. In the illustrated apparatus 9010, the rotary valve member 9044 takes the form of an inlet selector sleeve. The rotary valve member 9044 and the valve inlet 9028 are configured for relative rotation to each other such that rotation causes the rotary valve member 9044 to selectively block or obturate the valve inlet 9028. That is, during one phase of relative rotation, the valve inlet 9028 defines an open configuration in which pressure communication with the piston chamber 9020a is permitted and in another phase the valve inlet 9028 defines the closed configuration in which pressure communication with the piston chamber 9020a is prevented, substantially prevented or obturated.

[0705] In the illustrated apparatus 9010, the rotary valve member 9044 is fixed to the housing 9012 via thread connection 9206, such that relative rotation between the mandrel 9014 and the housing 9012 reconfigures the valve assembly 9024 as described further below.

[0706] In the illustrated apparatus 9010, the housing 9012 comprises or takes the form of a sleeve that acts as a non-rotating element (or as a relatively lower rotational speed element compared to the mandrel 9014).

[0707] In use, the mandrel 9014—which by virtue of threaded box connection 9208 is coupled to and rotates with a rotating string (not shown) of which the apparatus 9010 forms a part—rotates while the housing 9012—which by virtue of its engagement with borehole H—does not rotate or rotates at a lower rotational speed than the mandrel 9014. As the rotary valve member 9044 is fixed to the housing 9012 via thread connection 6906, relative rotation is also provided between the mandrel 9014 and the rotary valve member 9044.

[0708] The valve assembly 9024 is operated by relative rotation between the mandrel 9014 and the housing 9012 and the rotary valve member 9044 to be cyclically reconfigured between: a pressure configuration in which the piston chamber 9020a is in pressure communication with the valve inlet 9028 and isolated from the valve exhaust 9030 to permit the piston 9016 to move in the first axial direction A in accordance with the piston chamber 9020a being pressurised via the valve inlet 9028; and an exhaust configuration in which the piston chamber 9020a is isolated from the valve inlet 9028 and in pressure communication with the valve exhaust 9030 to permit the piston chamber 9020a to be depressurised and the piston 9016 to move in the second axial direction B.

[0709] FIGS. 47 and 48 show the apparatus 9010 in a first phase of rotation corresponding to the exhaust configuration in which the apparatus 9010 prevents or restricts fluid communication between axial throughbore 9038 of the apparatus 9010 and piston chamber 9020a via valve inlet 9028 but permits fluid communication between piston chamber 9020a and the valve exhaust 9030.

[0710] FIGS. 49 and 50 show the apparatus 9010 in a second phase of rotation corresponding to the pressure configuration in which the apparatus 010 permits fluid communication between axial throughbore 9038 and piston chamber 9020a via valve inlet 9028 but prevents or restricts fluid communication between axial throughbore 9038 and the valve exhaust 9030.

[0711] When the apparatus 9010 defines the pressure configuration, fluid pressure acting on the piston 9016 urges the piston 9016 axially relative to piston housing 9018 against the bias of spring arrangement 9202. Fluid in piston chamber 9020b is displaced through exhaust ports 9204, thereby preventing a hydraulic lock.

[0712] It can be seen that the piston 9016 is coupled to a shaft 9095 by a coupling arrangement 9210, which in the illustrated apparatus 9010 takes the form of a thread connection. As such, axial movement of the piston 9016 also moves the shaft 9095 axially.

[0713] As shown in FIGS. 47 and 49, a distal end portion of the shaft 9095 is coupled to an output shaft 9212 of the apparatus 9010 by a coupling arrangement 9214, which in the illustrated apparatus 9010 takes the form of a thread connection. The output shaft 9212 has a coupling arrangement 9216, which in the illustrated apparatus 9010 takes the form of a thread connection formed on an outer surface of the output shaft 9212. The coupling arrangement 9216 may be utilised to transmit the applied axial force output from the apparatus 9010 to a connected component or assembly of the apparatus 9010 or other connected tool.

[0714] A proximal end portion of the piston housing 9018 is coupled to the mandrel 9014 by a coupling arrangement 9220, which in the illustrated apparatus 9010 takes the form of a thread connection. As such, rotational movement and/or applied torque from the mandrel 9014 is transmitted to the piston housing 9018. A distal end portion of the piston housing 9018 is coupled to a bottom sub 9222 of the apparatus 9010 by a coupling arrangement 9224, which in the illustrated apparatus 9010 takes the form of a thread connection. The bottom sub 9222 comprises a further coupling arrangement 9226, which in the illustrated apparatus 9010 takes the form of a thread connection formed on an outer surface of the bottom sub 9222. The coupling arrangement 9222 facilitates connection and transmission of rotational movement and/or applied torque to downhole components of the tool string, such as the housing of a connected tool, where required.

[0715] As shown in FIGS. 47 and 49, a key 9228 is provided and functions to transmit torque from the mandrel 9014 (via the piston housing 9018 and the shaft 9095) to the output shaft 9212.

[0716] As described above, the apparatus 9010 may be utilised to generate an applied axial force output for transmission to a connected component, assembly or tool.

[0717] FIGS. 51 to 54 of the accompanying drawings show an alternative reciprocating drive apparatus 10010 in the form of an axial reciprocator apparatus.

[0718] In use, the apparatus 10010 is configured to generate an applied axial force output for transmission to a connected component or assembly of the apparatus 10010 or other connected tool.

[0719] The apparatus 10010 is similar to the apparatus 8010 described above and like components are represented by like reference signs incremented by 10000.

[0720] As shown, the apparatus 10010 comprises a housing 10012 and a mandrel 10014, the mandrel 10014 and the housing 10012 configurable to be rotated relative to each other. It will be understood that reference to relative rotation between the housing 10012 and the mandrel 10014 may include the apparatus 10010 being configured such that: the mandrel 10014 rotates while the housing 10012 is stationary; such that the housing 10012 rotates while the mandrel 10014 is stationary; or such that the mandrel 10014 and the housing 10012 both rotate. Beneficially, this facilitates flexibility in that hammering operations may be carried out in a number of different operational scenarios.

[0721] The apparatus 10010 further comprises a reciprocating piston 10016 mounted within piston housing 10018 so as to define a first piston chamber 10020a (shown most clearly in FIG. 53) and a second piston chamber 10020b. The piston 10016 is moveable within the first and second piston chambers 10020a,10020b in reverse first and second axial directions A, B.

[0722] The apparatus 10010 further comprises a rotary valve assembly 10024 comprising a valve inlet 10028 for communicating with a pressure region P and a valve exhaust 10030 for communicating with an exhaust region E.

[0723] The rotary valve assembly 10024 comprises a rotary valve member 10044 operatively associated with the valve inlet 10028. In the illustrated apparatus 10010, the rotary valve member 10044 takes the form of an inlet selector sleeve. The rotary valve member 10044 and the valve inlet 10028 are configured for relative rotation to each other such that rotation causes the rotary valve member 10044 to selectively block or obturate the valve inlet 10028. That is, during one phase of relative rotation, the valve inlet 10028 defines an open configuration in which pressure communication with the piston chamber 10020a is permitted and in another phase the valve inlet 10028 defines the closed configuration in which pressure communication with the piston chamber 10020a is prevented, substantially prevented or obturated.

[0724] The rotary valve member 10044 is supported within the apparatus 10010 by bearings 10248.

[0725] FIGS. 51 and 52 show the apparatus 10010 in a first phase of rotation corresponding to the exhaust configuration in which the apparatus 10010 prevents fluid communication between axial throughbore 10038 and piston chamber 10020a via valve inlet 10028 but permits fluid communication between axial throughbore 10038 and the valve exhaust 10030.

[0726] As shown, when the apparatus 10010 defines the exhaust configuration the spring arrangement 10202 urges the piston 10016 axially relative to piston housing 10018 in the direction B.

[0727] FIGS. 53 and 54 show the apparatus 10010 in a second phase of rotation corresponding to the pressure configuration in which the apparatus 10010 permits fluid communication between axial throughbore 10038 and piston chamber 10020a via valve inlet 10028 but prevents or restricts fluid communication between axial throughbore 10038 and the valve exhaust 10030.

[0728] As shown, when the apparatus 10010 defines the pressure configuration fluid pressure acting on the piston 10016 urges the piston 10016 axially relative to piston housing 10018 against the bias of spring arrangement 10202. Fluid in piston chamber 10020b is displaced through exhaust ports 10204, thereby preventing a hydraulic lock.

[0729] It can be seen that the piston 10016 is coupled to a shaft 10095 by a coupling arrangement 10210, which in the illustrated apparatus 10010 takes the form of a threaded connection. As such, axial movement of the piston 10016 also moves the shaft 10095 axially.

[0730] As shown, a distal end portion of the shaft 10095 is coupled to an output shaft 10212 of the apparatus 10010 by a coupling arrangement 10214, which in the illustrated apparatus 10010 takes the form of a thread connection. The output shaft 10212 has a coupling arrangement 10216, which in the illustrated apparatus 10010 takes the form of a thread connection formed on an outer surface of the output shaft 10212. The coupling arrangement 10216 may be utilised to transmit the applied axial force output from the apparatus 10010 to a connected component or assembly of the apparatus 10010 or other connected tool.

[0731] As shown, a proximal end portion of the piston housing 10018 is coupled to the housing 10012 by a coupling arrangement 10220, which in the illustrated apparatus 10010 takes the form of a thread connection. A distal end portion of the piston housing 10018 is coupled to a bottom sub 10222 of the apparatus 10010 by a coupling arrangement 10224, which in the illustrated apparatus 10010 takes the form of a thread connection. The bottom sub 10222 comprises a further coupling arrangement 10226, which in the illustrated apparatus 10010 takes the form of a thread connection formed on an outer surface of the bottom sub 10222.

[0732] As shown in FIGS. 51 and 53, a key 10228 is provided and functions to rotationally lock the shaft 10095 and the output shaft 10212 to the piston housing 10018. While in the illustrated apparatus 10010 a key 10228 is provided, it will be understood that in other forms of the apparatus the key 10228 may be omitted.

[0733] As described above, the apparatus 10010 may be utilised to generate an applied axial force output for transmission to a connected component or assembly of the apparatus 10010 or other connected tool.

[0734] FIGS. 55 and 56 of the accompanying drawings respectively show a pumping tool T5 and a packer tool T6 comprising a reciprocator apparatus according to the present disclosure. For illustrative purposes, the tools T5 and T6 employ the reciprocator apparatus 10010. However, it will be recognised that the tools T5 or T6 may alternatively employ the reciprocator apparatus 910.

[0735] Various modifications may be made without departing from the scope of the invention as defined in the appended claims.

[0736] For example, whereas the apparatus 6010, 8010, 9010,10010 show a single acting spring return arrangement, the apparatus may alternatively comprise a double acting spring return arrangement.

[0737] In some instances, a plurality of piston may be arranged in series to present additive piston area to generate greater applied force.

[0738] It will be recognised that the above described apparatus may be utilised in a wide variety of tools, including for example but not exclusively a drilling tool, a fluid pump, a pressure multiplier, a mechanical jack, a radial impactor, a radial punch, an oscillating casing scrapers and/or brush tool, a casing/tubing cutter, a casing/tubing deformers, or other suitable tool.

[0739] It will be understood that references herein to the engagement with the borehole H includes, in open hole applications, engagement with the bore wall and, in cased hole applications, engagement with the inner wall of the bore-lining tubing such as casing.