GB2602056A

GB2602056A - Jarring apparatus

Info

Publication number: GB2602056A
Application number: GB2019918.8A
Authority: GB
Inventors: Barnes Moyes Peter
Original assignee: Rotojar Innovations Ltd
Current assignee: Rotojar Innovations Ltd
Priority date: 2020-12-16
Filing date: 2020-12-16
Publication date: 2022-06-22
Also published as: GB202019918D0

Abstract

A jarring 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 further comprises a jarring piston 16 mounted within a piston housing 18 to define a piston chamber 20a, 20b, wherein the jarring piston 16 is moveable in reverse first and second axial directions and a rotary valve 22 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 22 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, 20b is in pressure communication with the valve 28 inlet and isolated from the valve exhaust 30 to permit the jarring piston to move in the first axial direction in accordance with the piston chamber being pressurised via the valve inlet When in the exhaust configuration the piston chamber is isolated from the valve inlet and m pressure communication with the valve exhaust to permit the piston chamber to be depressurised and the jarring piston to move in the second axial direction. Movement of the jarring piston 16 in at least one of the first and second axial directions generates a jarring force within the apparatus.

Description

JARRING APPARATUS

FIELD

The present disclosure relates to a jarring apparatus, a tool comprising the jarring apparatus, and to a method for generating jarring forces using the jarring apparatus.

BACKGROUND

Many industries require the application of jarring forces to support certain operations. For example, in the oil and gas exploration and production industry, jarring apparatus might be used downhole to apply jarring to a stuck object, such as a stuck tool, drill bit, drill string, bottom hole assembly (BHA) and the like. Further, it might be desirable to apply jarring forces during the process of drilling, for example to apply a hammer drilling effect, and/or be available in the event of a drill bit or string becoming stuck. Jarring may also be necessary when pulling equipment, tools and infrastructure from a wellbore, for example in the process of removing casing from a well, and/or when running equipment into a wellbore, for example in the process of running lower completions, and the like. Other jarring applications may include piling, for example.

Generally, a jarring apparatus is a device used to deliver an impact load to another component such as a BHA. Known jarring apparatus operate by storing energy, such as in a drilling string, for example by applying tension within the string, and suddenly releasing this energy to cause two impact surfaces to move axially and strike each other, creating an impact or jarring force.

Jarring apparatus are known which operate in response to a linear activation input, and are thus typically known as linear jarring apparatus.

Proposals have also been made concerning jarring apparatus which can provide a linear jar in response to a rotational drive input, such as from a drill string. In some proposals "rotary jarring" is provided by interaction of opposing rotary cams each having inter-engaging ramp profiles which gradually increase in a rotational direction until reaching a peak. During relative rotation of the cams the ramped surfaces interact to achieve relative axial displacement, and once the opposing cams peak they effectively drop-off and impact together, thus generating a jarring force.

While such rotary jarring can in some instances provide benefits over linear jarring concepts, some problems may arise. For example, the nature of the cam surfaces is such that as the cams approach their peak displacement the contact surface area reduces which can generate very significant stresses within the cams, theoretically tending to infinity at the drop-off point. Further, the cams themselves are subject to direct impact contact therebetween. As such, the cams may be subject to failure.

SUMMARY

Aspects of the present disclosure relate to a jarring apparatus, a tool comprising the jarring apparatus, and to a method for generating jarring forces.

An aspect of the present disclosure relates to a jarring apparatus, comprising: a housing; a mandrel, wherein the mandrel and the housing are configurable to be rotated relative to each other; a jarring piston mounted within a piston housing to define a piston chamber, wherein the jarring 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 jarring 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 jarring piston to move in the second axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

In use, continued relative rotation between the housing and the mandrel operates the rotary valve assembly to cause the piston chamber to be cyclically pressurised and depressurised to permit reciprocating movement of the jarring piston to generate repeated jarring forces within the apparatus.

As jarring forces are generated by relative rotation between the mandrel and the housing, the jarring apparatus may be defined as a rotary jarring apparatus. In this case, the frequency of generated jarring forces will be a function of the relative rotational speed between the mandrel and the housing, which may be infinitely variable to thus provide infinite variability of the jarring frequency, providing significant advantages.

Furthermore, as jarring forces are generated as a result of fluid pressure, the jarring apparatus may be defined as a fluid actuated jarring apparatus, for example a hydraulically actuated jarring apparatus. This may provide 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. In downhole applications, for example, the apparatus may be particularly beneficial in extended reach, high angle or horizontal wellbores which can present significant challenges to conventional tools and equipment due to the restrictions on the ability to apply force and/or weight in the horizontal section of the bore.

In use, the apparatus may be used in combination with the pressure and exhaust regions such that a pressure differential is applied across the rotary valve assembly. Specifically, the pressure within the pressure region may be elevated above the pressure in the exhaust region. In particular, the pressure within the pressure region may be sufficient (for example sufficiently high) to pressurise the piston chamber to permit the jarring piston to move in the first axial direction, and the pressure within the exhaust region may be sufficient (for example sufficiently low) to permit the piston chamber to be depressurised and the jarring piston to move in the second axial direction.

The jarring forces generated by the jarring apparatus can be significant. For illustrative purposes, a pressure differential of 200 psi (13.79 bar) acting across a jarring piston area of 25 in2 (0.016 m2), and with a 6 inch (0.152 metres) piston of 374 lb mass (170 kg mass) displacement displacing 148.41 ins (2.432 Litres) of fluid, is capable of generating approximately 180 klbf (800.68 kN) jarring or impact force. However, it will be understood that in many applications, such as downhole applications, the applied pressure or pressure differential may be significantly greater, with corresponding greater jarring force being generated by the jarring apparatus. In the case of downhole applications, for example, the pressure may be in the order of thousands of psi.

The jarring apparatus may be configured to operate irrespective of the direction of the pressure differential applied across the rotary valve assembly. As an example, in one mode of operation, suggested above, the pressure of the pressure region may be higher than the pressure of the exhaust region. However, should the pressure differential be reversed then what was previously the pressure region becomes the exhaust region, and vice versa, and what was previously the valve inlet becomes the valve exhaust, and vice versa. In this respect, it should be recognised that the valve inlet and the pressure region, and valve exhaust and exhaust region, may be defined as such in accordance with the direction of an applied pressure differential applied across the rotary valve assembly. With this in mind, although features will be defined herein as relating to the valve inlet and valve exhaust (and pressure and exhaust regions), 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) could switch depending on the operational conditions.

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

The ability for the apparatus to be employed irrespective of the direction of the pressure differential applied across the rotary valve assembly may provide 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 first and second regions suffers some kind of failure preventing pressure to be elevated therein to the required level. Further, the flexibility of the apparatus to function irrespective of the direction of the pressure differential may provide advantages in allowing the same apparatus to be used in multiple different applications where a particular pressure differential direction is preferred.

As described above, movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus. In some examples, jarring forces may be generated within the jarring apparatus by movement of the jarring piston in both the first and second axial directions. In other examples, movement of the jarring piston in one of the first and second axial directions generates a jarring force within the apparatus. In such embodiments, the jarring apparatus may be configured to generate jarring forces in one of said axial directions and may dampen or otherwise control transmission of forces in the other of said axial directions.

The ability to generate jarring forces in one of said axial directions and dampen or otherwise control transmission of forces in the other of said axial directions may beneficially facilitate the preferential transmission of the jarring forces, for example but not exclusively to a selected region or tool and/or protect other selected regions or tools.

The jarring apparatus may comprise an axial throughbore.

The jarring apparatus may be configurable in a first, open, configuration which permits access, e.g. full bore or substantially full bore access, through the axial throughbore of the jarring apparatus. The jarring apparatus may be configurable in a second, obturated, configuration in which access through the jarring apparatus is restricted or blocked.

The jarring apparatus may be reconfigurable between the first and second configurations, that is from the first configuration to the second configuration and vice-versa.

In the first, open, configuration, the jarring apparatus may beneficially facilitate full flow and/or passage of tools through the jarring apparatus. Thus, in circumstances where jarring is not required the jarring apparatus does not impinge on the passage of the fluid and/or tools through the jarring apparatus.

The second, obturated, configuration may provide an elevated pressure within the jarring apparatus which may be utilised by the jarring apparatus. For example, where the second, obturated, configuration forms a partial restriction through the axial throughbore the restriction may generate a back pressure for use in operation of the jarring apparatus.

Alternatively, where the second, obturated, configuration prevents or substantially prevents access through the axial throughbore, an elevated pressure region may be created within the jarring upstream of the blockage, for use in operation of the jarring apparatus.

Relative axial movement of the mandrel and the housing may be utilised to align lateral flow passages, e.g. ports, and bring the jarring apparatus into jarring mode, as will be described further below.

As described above, the jarring apparatus comprises a housing and a mandrel mounted within the housing, the mandrel and the housing being configurable to be rotated relative to each other.

It will be understood that reference to relative rotation between the housing and the mandrel may include the jarring apparatus being configured such that: the mandrel rotates while the housing is stationary; such that the housing rotates while the mandrel is stationary; or such that the mandrel and the housing both rotate.

Beneficially, this facilitates flexibility in that jarring operations may be carried out in a number of different operational scenarios.

It will be understood that while the terms "housing" and "mandrel" have been used herein for convenience, these components may alternatively be referred to as a first structure or first body portion and a second structure or second body portion of the jarring apparatus, the first structure or body portion and the second structure or body portion being rotatable relative to each other. In this respect the term "housing" is not intended to be limiting in terms of a component which houses another component (e.g., the second structure/body or mandrel), and similarly the term "mandrel" is not intended to be limiting in terms of a component about which another component (e.g., the first structure/body or housing) is mounted.

In this respect, an aspect of the disclosure may relate a jarring apparatus, comprising: a first structure or body portion; a second structure or body portion, wherein the first and second structures or body portions are configurable to be rotated relative to each other; a jarring piston mounted within a piston housing to define a piston chamber, wherein the jarring 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 first and second structures or body portions 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 jarring 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 jarring piston to move in the second axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

The housing may be disposed at least partially around the mandrel. The mandrel may be fully disposed within the housing. The mandrel may be partially disposed within the housing.

The mandrel may be mounted within the housing, wholly or partially.

The housing and the mandrel may be disposed and/or mounted axially end to end. The mandrel may be positioned and/or mounted above or below the housing. The housing and the mandrel may be disposed and/or mounted co-axially or substantially co-axially.

Where the housing and the mandrel are disposed and/or mounted axially relative to each other, the housing may define a first housing part and the mandrel may define a second housing part.

The housing may be tubular. The housing may comprise a plurality of components. Alternatively, the housing may comprise a single or unitary component.

The housing may define the axial throughbore of the jarring apparatus.

The housing may define the valve exhaust. The housing may define the valve inlet.

The housing may comprise one or more lateral flow passages. One or more of the lateral flow passages of the housing may define or communicate with the valve exhaust. One or more of the lateral flow passages of the housing may define or communicate with the valve inlet.

In particular embodiments, the housing may comprise a plurality of the lateral flow passages, for example but not exclusively two lateral flow passages, three lateral flow passages, four or more lateral flow passages The lateral flow passages may be arranged circumferentially and/or axially.

At least one of the lateral flow passages of the housing may be disposed at a first, uphole, location relative to the jarring piston. Said lateral flow passages may define an upper valve exhaust of the jarring apparatus. In particular embodiments, a plurality of the lateral flow passages of the housing may be disposed at the first, uphole, location relative to the jarring piston.

At least one of the lateral flow passage of the housing may be disposed at a second, downhole, location relative to the jarring piston. Said lateral flow passages may define a lower valve exhaust of the jarring apparatus. In particular embodiments, a plurality of the lateral flow passages of the housing may be disposed at the second, downhole, location relative to the jarring piston.

The mandrel may be tubular. The mandrel may comprise a plurality of components. Alternatively, the mandrel may comprise a single or unitary component.

The mandrel may define the axial throughbore of the jarring apparatus.

The mandrel may be disposed and/or mounted concentrically or substantially concentrically within the housing. The mandrel may be disposed and/or mounted eccentrically within the housing.

The mandrel may be rotatably coupled to the housing. The mandrel may be rotatably coupled to the housing by one or more rotary bearing. The mandrel may be axially coupled to the housing. The mandrel may be rotatably and axially coupled to the housing. For example, the mandrel may be rotatably and axially coupled to the housing by a spline connection.

The mandrel and the housing may be rotatably fixed such that the mandrel and the housing rotate together, until released. The mandrel and the housing may be rotatably coupled, and wherein: in a first configuration the mandrel and the housing may be rotatably fixed such that the mandrel and the housing are configured to rotate together; and in a second configuration the mandrel and the housing may be released for relative rotation.

The mandrel and the housing may be configured, e.g. shaped and/or dimensioned, so as to define an axial flow passage therebetween. The axial flow passage may be annular or part annular. The axial flow passage may provide fluid communication between the valve inlet and the piston chamber. The axial flow passage may be radially offset, .e.g. may be disposed radially outwards, from the axial throughbore. The apparatus may be configured to selectively permit fluid communication between the axial throughbore and the axial flow passage.

The mandrel may define the valve inlet. The mandrel may define the valve exhaust.

The mandrel may comprise one or more lateral flow passages. One or more of the lateral flow passages of the mandrel may define or communicate with the valve inlet. One or more of the lateral flow passages of the mandrel may define or communicate with the valve inlet.

In particular embodiments, the mandrel may comprise a plurality of lateral flow passages.

The lateral flow passages may be arranged circumferentially and/or axially.

At least one of the lateral flow passages of the mandrel may be disposed at a first, uphole, location relative to the jarring piston. Said lateral flow passage or passages may define an upper valve inlet of the jarring apparatus. In particular embodiments, a plurality of the lateral flow passages may be disposed at the first, uphole, location relative to the jarring piston.

At least one of the lateral flow passages of the mandrel may be disposed at a second, downhole, location relative to the jarring piston. Said lateral flow passage or passages may define a lower valve inlet of the jarring apparatus. In particular embodiments, a plurality of the lateral flow passages may be disposed at the second, downhole, location relative to the jarring piston.

In some examples, the one or more lateral flow passages of the mandrel may be provided on a circumferential surface of the mandrel. This may allow the flow area to be readily increased and/or decreased simply by axially extending or reducing the length of the one or more lateral flow passages. The number and/or configuration, e.g. dimensions or form, of the lateral flow passages of the mandrel may be selected in accordance with considerations such as total required inlet or exhaust area, jarring frequency and/or the like. Moreover, the ability to increase the flow area may allow a more rapid pressurisation and depressurisation which may be more explosive in terms of the jarring forces generated.

The jarring apparatus may be configured so that the flow area of the valve inlet and the valve exhaust are the same or substantially the same.

As described above, movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

In particular but not exclusively, when the apparatus is configured to cyclically move the jarring piston in first and second axial directions (in other words the jarring piston is double-acting), the flow areas of the valve inlet and valve exhaust may be matched for each direction. For example, the relative flow area size of the valve inlet and valve exhaust associated with generating upwards jarring forces may be increased or maximised while the flow area size of the valve inlet and valve exhaust associated with the return/down-stroke may be reduced or minimised.

Alternatively, the jarring apparatus may be configured so that the flow area of the valve inlet and the vale exhaust are different. By selecting the flow area of the valve inlet and the valve outlet to be different, the jarring apparatus may be tuned to reduce damping or choking and/or increase damping or choking, as required.

The relative flow area of the valve inlet and the valve exhaust may be configured to reduce damping or choking of fluid flow for example where it is desired to facilitate more rapid exhaust of fluid, such that the impulse of the jarring piston, and corresponding jarring force generated, is increased. This may be achieved, for example, by increasing the flow area of the valve exhaust relative to the flow area of the valve inlet.

The relative flow area of the valve inlet and the valve exhaust may be configured to increase damping or choking of fluid where it is desired to dampen or control movement of the jarring piston, and thereby limit the impulse and corresponding jarring force, generated. This may be achieved, for example, by decreasing the flow area of the exhaust relative to the flow area of the valve inlet.

As described above, the rotary valve assembly is 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 jarring 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 jarring piston to move in the second axial direction, The relative opening and closure timing of the valve inlet and the valve exhaust may be tuned to reduce damping or choking and/or increase damping or choking, as required.

The opening and closure timing of the valve inlet and the valve exhaust may be configured to reduce damping or choking of fluid flow for example where it is desired to facilitate more rapid exhaust of fluid, such that the impulse of the jarring piston, and corresponding jarring force generated, is increased.

The opening and closure timing of the valve inlet and the valve exhaust may be configured to increase damping or choking of fluid flow for example where it is desired to dampen or control movement of the jarring piston, and thereby limit the impulse and corresponding jarring force, generated.

As described above, the rotary valve assembly comprises 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 jarring 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 jarring piston to move in the second axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

The rotary valve assembly may be configured to facilitate selective fluid communication between the valve inlet and the axial throughbore.

The rotary valve assembly may be configured to facilitate selective fluid communication between the axial flow passage defined between the mandrel and the housing and the piston chamber.

The valve inlet may comprise one or more inlet ports. The inlet ports may form the lateral flow passages of the mandrel. The inlet ports may be defined as pressure ports. The number and/or configuration, e.g. dimensions, of the inlet ports may be selected in accordance with considerations such as total required inlet or exhaust area, jarring frequency and/or the like.

In some examples, the one or more inlet ports may be provided on a circumferential surface of the mandrel. This may allow the area to be readily increased simply by axially extending their length. Moreover, this may allow a more rapid pressurisation and depressurisation which may be more explosive in terms of the jarring force generated.

The valve inlet may be rotatably fixed to one of the mandrel and the housing.

The valve inlet may be integrally formed with one of the mandrel and the housing.

Alternatively, the valve inlet may be provided on a valve body.

The inlet ports may be provided through a wall of the mandrel.

The inlet ports may be provided on an inlet body. The inlet body may be configured for coupling to or form part of the mandrel or housing.

In some examples, the valve inlet may be configured to be arranged in pressure communication with a conduit which contains a fluid at a desired pressure. Such a conduit may be routed in any suitable form to facilitate communication of pressure from a pressure source (e.g., a pump system, hydrostatic head etc.) to the valve inlet. In some examples, which will be described in further detail below, the mandrel may define a conduit which provides said pressure communication.

In some examples, the jarring apparatus may not comprise a valve inlet, the jarring apparatus being operable by manipulation, e.g. pressure manipulation, of the valve exhaust.

The valve exhaust may comprise one or more outlet ports. The outlet ports may form the lateral flow passages of the housing. The number of outlet ports may be selected in accordance with considerations such as total required inlet or outlet area, jarring frequency and/or the like.

The outlet ports may be dimensioned to limit or prevent ingress of debris from the exhaust region, e.g. annulus into the piston chamber. For example, the outlet ports may be provided with a screen, such as a mesh, and/or a filter, so as to limit debris ingress from the exhaust region, e.g. annulus, getting into the piston chamber.

The valve exhaust may be rotatably fixed to one of the mandrel and the housing.

The valve exhaust may be integrally formed with one of the mandrel and the housing. In particular embodiments, the valve exhaust may be integrally formed with the housing.

The valve exhaust may be provided on an outlet body.

The outlet body may be configured for coupling to or form part of the mandrel or housing.

In some examples, the ports may be provided on a circumferential surface of the housing. This may allow the area to be readily increased simply by axially extending the length. This may allow a more rapid pressurisation and depressurisation which may be more explosive in terms of the jarring force generated.

The valve exhaust of the rotary valve assembly may be configured, for example by its position, construction and/or the like, to be arranged in pressure communication with an exhaust region. Such an exhaust region may provide suitable pressure conditions to permit the piston chamber to be depressurised. The pressure source or region and exhaust region may be provided in various ways, some examples of which will be described later below.

In some examples, the jarring apparatus may not comprise a valve exhaust, the jarring apparatus being operable by manipulation, e.g. pressure manipulation, of the valve inlet.

The rotary valve assembly may be axially and/or radially interposed between the mandrel and the housing. The rotary valve assembly may be disposed in the axial flow passage formed between the outside of the mandrel and the inside of the housing.

The rotary valve assembly may form or form part of a rotary valve arrangement. The rotary valve arrangement may comprise a single rotary valve assembly. Alternatively, the rotary valve arrangement may comprise first and second rotary valve assemblies, for example in the form of an upper rotary valve assembly and a lower rotary valve assembly.

The rotary valve assembly may form a first rotary valve assembly of a rotary valve arrangement of the jarring apparatus, and the rotary valve arrangement may comprise a second rotary valve assembly.

The first rotary valve assembly and the second rotary valve assembly may be disposed either side of and/or may communicate with respective sides of the jarring piston.

The rotary valve assembly may comprise at least one rotary valve member which is rotatably fixed to one of the housing and the mandrel.

The rotary valve member, or where the rotary valve assembly comprises a plurality of the rotary valve members at least one of the rotary valve members, may be integrally formed with the one of the housing and the mandrel. Alternatively, the rotary valve member, or where the rotary valve assembly comprises a plurality of the rotary valve members may comprise a separate component.

In some examples, the rotary valve assembly comprises a single rotary valve member. In such embodiments, the rotary valve member may be operatively associated with the valve inlet and the valve exhaust.

In other embodiments, the rotary valve assembly comprises a plurality of rotary valve members. For example, the rotary valve assembly may comprise a rotary valve member operatively associated with the valve inlet, or each valve inlet where there are a plurality of valve inlets. The rotary valve assembly may comprise a rotary valve member operatively associated with the valve exhaust, or each valve exhaust where there are a plurality of valve exhausts.

The rotary valve assembly may comprise or take the form of one or more inlet selector, e.g. one or more inlet selector sleeve.

The one or more inlet selector may form the rotary valve member operatively associated with the valve inlet. The one or more inlet selector may be operatively associated with the valve inlet. The one or more inlet selector and the valve inlet may be configured for relative rotation to each other such that rotation causes the inlet selector sleeve or sleeves to selectively block or obturate the valve inlet(s). That is, during one phase of relative rotation, the valve inlet may define an open configuration in which pressure communication with the piston chamber is permitted and in another phase the valve inlet may define a closed configuration in which pressure communication is prevented, substantially prevented or obturated by the inlet selector sleeve.

The one or more inlet selector may be rotatably fixed to one of the housing and mandrel.

The one or more inlet selector may be coupled to one of the housing and the mandrel by a key arrangement or other suitable coupling arrangement.

The valve inlet may be rotatably fixed to one of the housing and the mandrel and the one or more inlet selector may be rotatably fixed to the other of the housing and the mandrel.

The valve inlet may be provided on an inlet body and the rotary valve assembly may comprise an inlet selector sleeve, wherein the inlet body and inlet selector sleeve are arranged to be rotatable relative to each other to selectively open and close the valve inlet. The inlet body and the inlet selector sleeve or sleeves may be configured such that relative rotation therebetween cyclically opens and closes the valve inlet(s). In this respect, the open condition may be such that pressure communication with the piston chamber is provided. The closed condition may substantially or fully prevent fluid communication with the piston chamber.

The one or more inlet selector may be tubular.

The one or more inlet selector may comprise one or more lateral flow passages. The lateral flow passages of the inlet selector may comprise flow ports. The one or more lateral flow passages may be circular or take the form of elongate slots.

The rotary valve assembly may comprise or take the form of one or more outlet selector, e.g. one or more outlet selector sleeves.

The one or more outlet selector may form the rotary valve member operatively associated with the valve exhaust. The one or more outlet selector and the valve exhaust may be configured for relative rotation to each other such that rotation causes the one or more outlet selector to selectively block or obturate the valve exhaust(s). That is, during one phase of relative rotation, the valve inlet may define an open configuration in which pressure communication with the piston chamber is permitted and in another phase the valve inlet may define a closed configuration in which pressure communication is prevented, substantially prevented or obturated by the outlet selector sleeve.

The outlet selector sleeve may be rotatably fixed to one or the housing and mandrel. The valve exhaust may be rotatably fixed to one of the housing and the mandrel and the outlet selector sleeve may be rotatably fixed to the other of the housing and the mandrel. In particular embodiments, the outlet selector sleeve may be coupled to the mandrel.

The outlet selector sleeve may be coupled to the mandrel by a key arrangement or other suitable coupling arrangement.

The one or more outlet selector sleeve may be tubular.

The one or more outlet selector may comprise one or more lateral flow passages. The lateral flow passages of the one or more outlet selector may comprise flow ports. The one or more lateral flow passages may be circular or take the form of elongate slots.

The inlet selector sleeve and the outlet selector sleeve may be separate components.

Alternatively, the inlet selector sleeve and the outlet selector sleeve may comprise a single component, for example may be integrally formed.

The valve assembly may form part of a valve arrangement of the jarring apparatus, the valve arrangement comprising a second valve assembly. The valve arrangement may comprise a first, upper, valve assembly and a second, lower, valve assembly.

The second valve assembly may comprise one or more valve inlet such as described above.

The second valve assembly may comprise one or more valve exhaust such as described above.

The second valve assembly comprise one or more rotary valve member as described above. In particular embodiments, the valve arrangement may comprise the first, upper, valve assembly, wherein said first valve assembly comprises one or more rotary valve member operatively associated with one or both of the upper valve inlet and the upper valve exhaust and a second, lower, valve assembly comprising one or more rotary valve member operatively associated with one or both of the lower valve inlet and the lower valve exhaust.

In use, the rotary valve arrangement may act to bias the jarring piston towards the first axial direction or the second axial direction when the valve assembly is in its pressure configuration. The rotary valve arrangement may form or form part of a biasing arrangement.

The jarring apparatus may comprise a first biasing arrangement which comprises the rotary valve assembly. In this respect, the first biasing arrangement may function to bias the jarring piston in the first axial direction when the valve assembly is in its pressure configuration. When the valve assembly is in the exhaust configuration such that the piston chamber is vented the jarring piston may move in the second direction under action or control of a second biasing arrangement.

In this example, with the provision of first and second biasing arrangements the jarring apparatus may be defined as comprising: a housing; a mandrel, wherein the mandrel and the housing are configurable to be rotated relative to each other; a jarring piston mounted within a piston housing to define a piston chamber, wherein the jarring piston is moveable in reverse first and second axial directions; a first biasing arrangement comprising a rotary valve assembly having a pressure port for communicating with a pressure region and an exhaust port for communicating with an exhaust region, the rotary valve assembly being operated during 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 pressure port and isolated from the exhaust port to permit the jarring piston to move in the first axial direction in accordance with the piston chamber being pressurised; and an exhaust configuration in which the piston chamber is isolated from the pressure port and in pressure communication with the exhaust port to permit the piston chamber to be vented and the jarring piston to move in the second axial direction under action or control of a second biasing arrangement, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

As described above, the rotary valve arrangement may comprise a single valve assembly or a plurality of rotary valve assemblies, said rotary valve assemblies forming a biasing arrangement of the jarring apparatus.

In embodiments comprising a single valve assembly, the jarring apparatus may comprise a second biasing arrangement. The second biasing arrangement may comprise or take the form of a mechanical biasing arrangement. The second biasing arrangement may comprise or take the form of a spring arrangement.

As described above, the jarring piston is disposed and/or mounted within the piston housing to define the piston chamber, the jarring piston being moveable in reverse first and second axial directions. The piston housing may form part of the housing or may be a separate component.

In some examples, the jarring piston may be interposed between the mandrel and the housing.

The jarring piston may be disposed within the piston chamber so as define first and second piston chamber portions.

The jarring apparatus may comprise co-operating impact surfaces, wherein engagement of the impact surfaces results in the jarring force.

The impact surfaces may comprise co-operating first and second impact surfaces.

The first impact surface may be provided on the jarring piston. In particular embodiments, the first impact surface may be provided on a hammer coupled to or forming part of the jarring piston.

The second impact surface may be formed on a surface of the housing and/or the mandrel. In particular embodiments, the second impact surface may be formed on an anvil coupled to or forming part of the mandrel or housing.

In use, the rotary valve assembly may be operable by relative rotation between the mandrel and the housing to be cyclically reconfigured between the pressure configuration and the exhaust configuration, so as to move the jarring piston in one of the first and second axial directions, said movement of the jarring piston engaging the first and second impact surfaces to generate the jarring force within the apparatus.

In some instances, however, the jarring apparatus may be configured so that the impact surfaces do not engage, said movement of the jarring piston itself being sufficient to generate jarring or agitation forces.

As described above, the jarring apparatus may be configured to dampen and/or control movement of the jarring piston.

The jarring arrangement may comprise means for controlling and/or dampening the movement of the piston in one of the axial directions.

The jarring apparatus may comprise a damper arrangement.

The damper arrangement may comprise or take the form of a mechanical damper arrangement and/or a fluid damper arrangement, for example hydraulic damper arrangement.

The jarring apparatus may comprise an end stop. The end stop may comprise or take the form of a buffer, for example a rubber buffer. Alternatively, the end stop may comprise or take the form of co-operating impact surfaces similar to the first and second impact surfaces described above.

The damper arrangement may comprise a dash-pot assembly. The dash-pot assembly may be coupled to or operatively associated with the jarring piston. In use, the dash-pot assembly may provide hydraulic dampening at the end of the travel of the jarring piston in the direction of buffering.

Alternatively or additionally, and as described above, the valve inlet and the valve exhaust flow areas may be choked so as to dampen and/or control the jarring force generated within the jarring apparatus.

Alternatively or additionally, and as described above, the opening and closure timings of the valve inlet and the valve exhaust may be configured to dampen and/or control the jarring force generated within the jarring apparatus.

Pressure may be applied in any suitable way. In one example, pressure may be elevated at the inlet by pressuring fluid in a seal space, such as a cavity, conduit and/or the like. Alternatively, pressure may be applied on a flow of fluid, for example by establishing fluid dynamic conditions which establish a desired backpressure.

The jarring apparatus may comprise, may be coupled to or operatively associated with a valve arrangement configured to generate the elevated pressure for use by the jarring apparatus. The valve arrangement may be configured to provide selective fluid communication through the axial throughbore of the jarring apparatus.

The valve arrangement may comprise a valve member. The valve member may comprise or take the form of a ball. The ball may comprise a throughbore.

The valve arrangement may comprise an upper valve seat and a lower valve seat. The valve member, e.g. ball, may be captivated between an upper valve seat and a lower valve seat.

The valve arrangement may comprise an actuator. The actuator may comprise or take the form of a linear actuator. The actuator may comprise or take the form of an actuator sleeve.

The valve arrangement may comprise a valve operator arrangement. The valve operator arrangement may comprise one or more operator members.

The one or more operator members may be disposed between and configured to couple the actuator to the valve member. The one or more operator members may be coupled to or configured to engage the actuator. For example, one or more of the operator members may comprise a tab which seats in a corresponding recess in the actuator. Other means for coupling or engaging the one or more operator members with the actuator may be used.

The one or more operator members may be coupled to or configured to engage the valve member. For example, one or more of the operator members may comprise a pin which seats in an offset slot in the valve member. Other means for coupling or engaging the one or more operator members with the valve member may be used.

In use, axial movement of the actuator sleeve may translate the operator members to pivot the valve member, e.g. ball, and thereby reconfigure the valve member from the open configuration to the closed configuration.

Rotation of the valve member, e.g. ball, may be limited. For example, rotation of the valve member may be limited to 1/4 turn. The valve arrangement may comprise a movement limiter.

The valve member may comprise an orifice. When the valve member, e.g. ball, defines the closed configuration, the orifice may be aligned with the axial throughbore. Flow through the orifice generates a back pressure for use by the jarring apparatus. The provision of the orifice may also mean that even when the valve arrangement defines the closed configuration, some fluid communication through the jarring apparatus is nevertheless provided. Beneficially, this permits the jarring apparatus to function without complete closure of the axial flow passage and, for example, permits circulation of fluid below the jarring apparatus and/or transmission of pressure forces which may be required to operate downhole tools.

The valve arrangement may comprise, may be coupled to operatively associated with an indexer mechanism. The indexer mechanism may comprise or take the form of a dog indexer.

The indexer mechanism may comprise one or more slots. The indexer mechanism may comprise one or more dogs. The one or more dogs may be configured to engage the one or more slots. The dog or dogs may be 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.

The indexer mechanism may comprise one or more further dogs, which may be defined as upper dogs. The one or more dogs may be provided in a recess in the mandrel, in particular an outer circumferential surface of the mandrel.

In use, relative axial movement of the mandrel and the housing aligns the dogs with corresponding recesses formed in the inner circumferential surface of the housing, allowing the dogs to move radially outwards and thereby stop further axial movement of the actuator.

The indexer mechanism may comprise a ramp profile. The ramp profile may be provided on the mandrel, in particular an outer circumferential surface of the mandrel.

In use, relative axial movement of the mandrel and the housing may urge the ramp profile into engagement with the further dogs, picking up the indexer mechanism and closing the valve arrangement.

The valve arrangement may thus be opened and closed repeatedly as required, by relative axial movement of the mandrel and the housing.

As described above, the jarring apparatus may be configured to generate significant jarring forces in at least one axial direction. In some examples, the jarring apparatus may comprise means to limit the transmission of forces. For example, the jarring apparatus may comprise a pressure regulator, e.g. pressure regulator, pressure relief valve (PRV) or the like. In use, the pressure regulator may be configured to vent pressure to the exhaust region on exceeding a predetermined threshold pressure.

The jarring apparatus may comprise, may be coupled to or operatively associated with one or more swivel. The swivel may be interposed, e.g. radially interposed between the mandrel and the housing.

The provision of one or more swivel may be particularly beneficial in downhole jarring applications such as running completions and the like having components which are unsuitable to transmission of rotary forces.

The swivel may comprise a thrust assembly.

The thrust assembly may comprise a first thrust profile. The first thrust profile may comprise or take the form of a shoulder. The first thrust profile, e.g. shoulder, may be formed or provided on the mandrel.

The thrust assembly may comprise a second thrust profile. The second thrust profile may comprise or take the form of a shoulder. The second thrust profile, e.g. shoulder, may be formed or provided on the housing.

The jarring apparatus may be configured such that the first and second thrust profiles may be axially separated and thus disengaged, wherein relative axial movement of the mandrel and the housing brings the first and second thrust profiles into engagement, such that axial loading may be transmitted between the mandrel and the housing via the thrust assembly, thus diverting such loading from other components within the apparatus.

The thrust assembly permits rotation between the first and second thrust profiles when engaged, such that the thrust assembly may function as a thrust bearing arrangement.

The thrust assembly may comprise one or more thrust bearing assembly.

In particular embodiments, the thrust assembly may comprise a plurality of thrust bearing assemblies. The thrust bearing assemblies may be arranged axially. Beneficially, the thrust bearing assemblies share the axial load force exerted on the thrust assembly.

The thrust bearing assembly may comprise one or more thrust bearings. At least one of the thrust bearings may comprise or take the form of a plain bearing, for example a PTFE thrust bearing or the like.

The thrust bearing assembly may comprise a carrier member. The one or more thrust bearings may be disposed on and carried by the carrier member. The carrier member may be annular or part annular. The carrier comprise or take the form of a sleeve.

The jarring apparatus may comprise, may be coupled to or operatively associated with a mechanism for providing cooling and/or lubrication of the thrust assembly.

The mechanism may comprise a seal arrangement. The seal arrangement may be interposed, e.g. radially interposed, between the mandrel and the housing.

The seal arrangement may comprise one or more seal elements and in particular embodiments the seal arrangement may comprise a plurality of seal elements. The seal arrangement may comprise a seal stack.

The mechanism for providing cooling and/or lubrication of the thrust assembly may comprise one or more lateral flow passages, e.g. flow ports. The one or more lateral flow passages, e.g. flow ports, may be circumferentially arranged and/or spaced. The one or more lateral flow passages may be configured to provide fluid communication between the axial throughbore of the jarring apparatus and the thrust assembly.

When seated, the seal arrangement may prevent or at least inhibit fluid communication to the thrust assembly. When unseated by relative axial movement between the mandrel and the housing, the one or more lateral flow passages, e.g. flow ports, fluid communication to the thrust assembly may be permitted, thereby acting to cool and/or lubricate the thrust assembly.

The jarring apparatus may be configured to generate one or more downwards or downhole-directed jarring forces within the jarring apparatus. The jarring apparatus may comprise co-operating impact surfaces arranged to generate one or more downwards or downhole-directed jarring forces. A first impact surface may comprise a shoulder. A second impact surface may comprise or may be provided on a separate member, such as an anvil or the like.

In use, relative axial movement of the housing and the mandrel may bring the first and second impact surfaces into engagement, so as to generate the one or more downwards or downhole-directed jarring forces within the apparatus.

The jarring apparatus may comprise, may be coupled to operatively associated with an axial trigger arrangement.

The axial trigger arrangement may be configured to selectively axially lock the mandrel and the housing. In a first configuration, the axial trigger arrangement may be configured to axially lock the mandrel and the housing. In a second configuration, the axial trigger arrangement may be configured to permit axial movement between the mandrel and the housing.

The axial trigger arrangement may comprise a locking profile. The locking profile may be provided on or coupled to the mandrel. The locking profile may comprise or take the form of a male profile. Alternatively, the locking profile may comprise or take the form of a female profile. The locking profile may comprise or take the form of a castellated or toothed profile or the like.

The axial trigger arrangement may comprise one or more locking keys. In some examples, the axial trigger arrangement comprises a single locking key. Alternatively, the axial trigger arrangement may comprise a plurality of locking keys. The one or more locking keys may be annular or part annular.

The one or more locking keys may be configured to engage the locking profile. The one or more locking keys may comprise a locking profile configured to engage the locking profile provided on or coupled to the mandrel. The locking profile may comprise or take the form of a male profile. Alternatively, the locking profile may comprise or take the form of a female profile. The locking profile may comprise or take the form of a castellated or toothed profile or the like.

The one or more locking keys may be reconfigurable between a retracted configuration, for example radially retracted configuration, and an extended configuration, for example radially extended configuration.

The one or more locking keys may be biased towards the retracted configuration. For example the one or more locking keys may be constructed from a resilient material such that the one or more keys are biased toward the retracted configuration and/or the jarring apparatus may comprise an resilient member for urging the one or more locking keys towards the retracted configuration.

The axial trigger arrangement may comprise a retainer for retaining the one or more locking keys in a radially retracted position.

The axial trigger arrangement may comprise a taper lock. The taper lock may form or form part of the retainer. The taper lock may comprise a lock bowl defining a tapered surface configured to engage a corresponding tapered surface on at least one of the locking keys.

The axial trigger arrangement may comprise a spring arrangement. The spring arrangement may form or form part of the retainer. The spring arrangement may comprise one or more spring elements, or other suitable biasing member. In particular embodiments, the spring arrangement may comprise a plurality of spring elements, such as a spring stack, and more particularly but not exclusively the spring arrangement may comprise a Belleville spring stack.

The spring arrangement may be coupled to or configured to engage the taper lock to urge the one or more locking keys towards their retracted configuration. For example, the spring arrangement may be configured to urge the tapered surface of the lock bowl towards the corresponding tapered surface on at least one of the locking keys so as to urge the one or more locking keys towards and/or retain the locking keys in their retracted configuration.

The axial trigger arrangement may be configured to move the one or more locking keys to the extended configuration in response to an axial pull or tensile force applied to the mandrel. The axial trigger arrangement may be configured to move the one or more locking keys to the extended configuration in response to an axial pull or tensile force above a predetermined threshold force, in particular the spring force of the spring arrangement.

Beneficially, the axial trigger arrangement may be resettable.

For example, it will be recognised that the axial trigger arrangement may, by virtue of application of a pull or tensile force above a predetermined threshold or a push, compressive or applied weight force above a predetermined threshold, may be reconfigurable between the first configuration in which the axial trigger arrangement is configured to axially lock the mandrel and the housing and the second configuration in which the axial trigger arrangement is configured to permit axial movement between the mandrel and the housing. The application of a pull or tensile force may, for example, facilitate an axial up jar operation and/or rotary jarring operation. The application of a push, compressive or applied weight force may, for example, facilitate an axial down jar operation.

The axial trigger arrangement may facilitate a predetermined axial (up or down) jar to be carried out.

Relative rotation between the first and second jarring assemblies to provide jarring may be achieved via a rotational drive mechanism. The rotational drive mechanism may be configured separately from the apparatus. Alternatively, or additionally, the apparatus may comprise a rotational drive mechanism.

The rotational drive mechanism may be coupled or otherwise associated with at least one of the first and second jarring assemblies and configured to provide a relative rotational movement therebetween.

The rotational drive mechanism may comprise a rotatable work string coupled to at least one of the first and second jarring assemblies. The work string may be defined by, for example, a drilling string.

The rotational drive mechanism may comprise a motor, such as an electric motor, pneumatic motor, hydraulic motor, mud motor or the like.

An aspect of the present disclosure relates a tool comprising the jarring apparatus according to the first aspect.

The tool may comprise a downhole tool.

The tool may comprise the valve arrangement configured to generate a back pressure for use by the jarring apparatus, as described above with respect to the first aspect.

The tool may comprise the thrust assembly, as described above with respect to the first aspect.

Tool may comprise the mechanism for providing cooling and/or lubrication of the thrust assembly, as described above with respect to the first aspect.

The tool may comprise the axial trigger arrangement, as described above with respect to the first aspect.

The tool may further comprise a top sub. The top sub may be generally tubular in construction. The top sub may comprise an axial throughbore extending therethrough. 10 An end portion, e.g. upper end portion, of the top sub may be configured for coupling the jarring apparatus to another component of a tool assembly, e.g. tool string. The top sub may define a connector for coupling the jarring apparatus to another component of a tool assembly. The connector may comprise or take the form of threaded connector. The connector may comprise or take the form of threaded male connector, such as a threaded pin connector, or female connector, such as a threaded box connector. In particular embodiments, the connector may comprise a threaded box connector.

An end portion, e.g. lower end portion, of the top sub may be configured for coupling to the mandrel. The top sub may define a profile configured for coupling to the mandrel, e.g. an upper end portion of the mandrel. The profile may comprise or take the form of a female profile. The profile may comprise or take the form of a male profile.

The top sub may be configured for coupling to the mandrel by a connector. The connector may comprise a thread connection.

The tool may comprise a bottom sub. The bottom sub may be generally tubular in construction having an axial throughbore extending therethrough.

An end portion, e.g. lower end portion, of the bottom sub may be configured for coupling the jarring apparatus to another component of a tool assembly, e.g. tool string.

The bottom sub may define a connector for coupling the jarring apparatus to said other component of the tool string. The connector may comprise or take the form of threaded connector. The connector may comprise or take the form of threaded male connector, such as a threaded pin connector, or female connector, such as a threaded box connector. In particular embodiments, the connector may comprise a threaded pin connector.

An end portion, e.g. upper end portion, of the bottom sub configured for coupling to the housing. The bottom sub may define a profile configured for coupling to the housing, e.g. an end portion of the housing. The profile may comprise or take the form of a female profile. In particular embodiments, the profile may comprise or take the form of a male profile.

The bottom sub may be configured for coupling to the housing by a connector. The connector may comprise a thread connection.

An aspect of the present disclosure relates to a method for generating jarring forces, the method comprising: providing a housing and a mandrel, wherein the mandrel and the housing are configurable to be rotated relative to each other; providing a jarring piston mounted within a piston housing to define a piston chamber, wherein the jarring piston is moveable in reverse first and second axial directions; and providing 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 jarring 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 jarring piston to move in the second axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

An aspect of the present disclosure relates to a method for generating jarring 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 jarring 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 jarring piston to move in the second axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

In some examples, the jarring apparatus may be for use within a wellbore. As such, the jarring apparatus may define a downhole jarring apparatus. The jarring apparatus may be configured to apply a jarring force to a pipe string, downhole tool, bottom hole assembly (BHA), such as a drilling BHA, or the like. The jarring apparatus may be configured for use in releasing an object which is stuck within a wellbore. In some examples the jarring apparatus may be deployable downhole on an elongate medium, such as wireline, coiled tubing, jointed tubing or the like. The jarring apparatus may be tractor deployed downhole.

The jarring apparatus may be configured for use in pulling plugs within a wellbore or associated infrastructure.

The jarring apparatus may be configured for use in pulling or retrieval operations associated with removal of infrastructure from a wellbore, such as fishing operations, pulling completions, casing, liner, conductor and the like.

The jarring apparatus may be configured for use in subsea applications, such as in piling applications, equipment removal applications, and the like In some applications, the jarring apparatus may be required to support load, for example significant load therethrough. For example, in a casing pulling operation the jarring apparatus may be directly or indirectly coupled to a casing string being pulled, which might generate loading, for example significant loading through the jarring apparatus of up to and beyond 4.5 MN.

The apparatus may be configured to permit axial jarring in one axial direction, such as in an upward or downward direction. The apparatus may be configured to permit axial jarring in opposing axial directions.

A aspect of the present disclosure relates to a jarring 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.

Another aspect of the present disclosure relates to a jarring apparatus comprising: an axial throughbore; and a mechanism disposed in the axial throughbore, wherein the mechanism is configurable between a first, open, configuration which permits access through the axial throughbore of the jarring apparatus and a second, obturated, configuration in which access through the axial throughbore of the jarring apparatus is restricted or blocked, said restriction or blockage providing an elevated fluid pressure or fluid pressure differential within the axial throughbore; and a jarring mechanism configured to utilise the elevated fluid pressure generated by the mechanism in the generation of jarring forces within the jarring apparatus.

The jarring apparatus may be configurable in the first, open, configuration which permits access, e.g. full bore or substantially full bore access, through the axial throughbore of the jarring apparatus. The jarring apparatus may be configurable in the second, obturated, configuration in which access through the jarring apparatus is restricted or blocked.

In the second, obturated, configuration, the restriction or blockage may provide an elevated pressure within the jarring apparatus which may be utilised by the jarring apparatus. For example, where the second, obturated, configuration forms a partial restriction through the axial throughbore the restriction may generate a back pressure for use in operation of the jarring apparatus. Alternatively, where the second, obturated, configuration prevents or substantially prevents access through the axial throughbore, an elevated pressure region may be created within the jarring upstream of the blockage, for use in operation of the jarring apparatus.

The jarring apparatus may comprise or take the form of a rotary jarring apparatus.

An aspect of the present disclosure relates to a jarring apparatus, comprising: a jarring piston mounted within a piston housing to define a piston chamber; a rotary valve assembly comprising a pressure port for communicating with a pressure region and a vent port for communicating with a vent region, the rotary valve assembly being cyclically reconfigured between: a pressure configuration in which the piston chamber is in pressure communication with the pressure port and isolated from the vent port to permit the jarring piston to move in a first axial direction in accordance with the piston chamber being pressurised; and a vent configuration in which the piston chamber is isolated from the pressure port and in pressure communication with the vent port to permit the piston chamber to be vented and the jarring piston to move in a second axial direction opposite the first axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

An aspect of the present disclosure relates to a jarring apparatus, comprising: a jarring piston axially moveable within a piston chamber; a rotary valve assembly comprising a first valve port for communicating with a first pressure region and a second valve port for communicating with a second pressure region in pressure communication with first and second pressure regions which in use are exposed to different pressures, the rotary valve assembly being rotatably operated to be cyclically reconfigured between: a first configuration in which the piston chamber is in pressure communication with the first pressure region and isolated from a second pressure region to permit the jarring piston to move in a first axial direction; and a second configuration in which the piston chamber is isolated from the first pressure region and in pressure communication with the second pressure region to permit the jarring piston to more in a second axial direction opposite the first axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

An aspect of the present disclosure relates to a jarring apparatus, comprising: an axially moveable jarring piston mounted within a piston housing to define first and second piston chambers isolated by a piston sealing arrangement; a rotary valve assembly being rotatably operated to be cyclically reconfigured between: a first configuration in which the first piston chamber is in pressure communication with a first pressure region to establish a first pressure differential between the first and second piston chambers and isolated from a second pressure region to permit the jarring piston to move in a first axial direction; and a second configuration in which the piston chamber is isolated from the first pressure region and in pressure communication with the second pressure region to permit the jarring piston to more in a second axial direction opposite the first axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

An aspect of the present disclosure relates to a jarring apparatus, comprising: a jarring piston axially moveable within a piston chamber; a rotary valve assembly being rotatably operated to be cyclically reconfigured between: a first configuration in which the piston chamber is in pressure communication with a first pressure region and isolated from a second pressure region to permit the jarring piston to move in a first axial direction; and a second configuration in which the piston chamber is isolated from the first pressure region and in pressure communication with the second pressure region to permit the jarring piston to more in a second axial direction opposite the first axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

An aspect of the present disclosure relates to a jarring apparatus, comprising: a piston chamber; a jarring piston axially moveable within the piston chamber; a control flow path extending between first and second pressure regions and being in pressure communication with the piston chamber; a rotary valve assembly mounted within the control flow path and being rotatable to be cyclically reconfigured between: a first configuration in which the piston chamber is in pressure communication with the first pressure region and isolated from the second pressure region to permit the jarring piston to move in a first axial direction; and a second configuration in which the piston chamber is isolated from the first pressure region and in pressure communication with the second pressure region to permit the jarring piston to more in a second axial direction opposite the first axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.

The invention is defined by the appended claims. However, for the purposes of the present disclosure it will be understood that any of the features defined above or described below may be utilised in isolation or in combination. For example, features described above in relation to one of the above aspects or below in relation to the detailed description below may be utilised in any other aspect, or together form a new aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects will now be described with reference to the accompanying drawings, in which: Figure 1 shows a longitudinal sectional view of a jarring apparatus; Figure 2 shows cross-sectional view A-A of the jarring apparatus shown in Figure Figure 3 shows cross-sectional view B-B of the jarring apparatus shown in Figure Figure 4 shows cross-sectional view C-C of the jarring apparatus shown in Figure Figure 5 shows cross-sectional view D-D of the jarring apparatus shown in Figure 1; Figure 6 shows the jarring apparatus shown in Figure 1, in a first phase of rotation; Figure 7 shows the jarring apparatus shown in Figure 1, in a second phase of rotation; Figure 8 shows cross-sectional view A-A of the jarring apparatus shown in Figure Figure 9 shows cross-sectional view B-B of the jarring apparatus shown in Figure Figure 10 shows cross-sectional view C-C of the jarring apparatus shown in Figure 7; Figure 11 shows cross-sectional view D-D of the jarring apparatus shown in Figure 7; Figure 12 shows a diagrammatic view of the jarring apparatus showing the relative position and state of components of the apparatus at different angular positions; Figure 13 shows a longitudinal sectional view of a downhole tool comprising the jarring apparatus of Figure 1, in a first phase of rotation; Figures 14 and 15 show a valve arrangement configured to generate back pressure for use in operation of the jarring apparatus; Figure 16 shows a longitudinal sectional view of the downhole tool of Figure 13, primed for performing a jarring operation; Figure 17 shows a perspective view of the valve arrangement shown configured to generate back pressure for use in operation of the jarring apparatus; Figure 18 shows a longitudinal sectional view of the downhole tool shown in Figure 13, in a second phase of rotation; Figure 19 to 23 show an alternative valve arrangement for the jarring apparatus; Figures 24 and 25 show alternative biasing arrangements for the jarring apparatus; Figure 26 shows a tool comprising an alternative jarring apparatus; Figure 27 shows part of an alternative jarring apparatus, in a first phase of rotation; and Figure 28 shows the part of the jarring apparatus shown in Figure 27, in a second phase of rotation.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring first to Figure 1 of the accompanying drawings, there is a jarring apparatus 10 for generating jarring forces.

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.

Referring now also to Figures 2 to 5 which cross-sectional views A-A, B-B, C-C and DD 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 piston chambers 20a,20b in reverse first and second axial directions A, B. The jarring apparatus 10 further comprises a rotary valve arrangement, generally denoted 22. As shown in Figure 1, the rotary valve arrangement comprises a first, upper, valve assembly, generally denoted 24, and a second, lower, valve assembly, generally denoted 26.

The upper rotary valve assembly 24 comprises a valve inlet 28 for communicating with a pressure region P and a valve exhaust 30 for communicating with an exhaust region E. Figure 2 of the accompanying drawings shows cross section A-A through the upper valve inlet 28 of the jarring apparatus 10. Figure 3 shows cross section B-B through the upper valve exhaust 30 of the jarring apparatus 10.

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 valve inlet 28 and isolated from the 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 valve inlet 28; and an exhaust configuration in which 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 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.

The lower rotary valve assembly 26 comprises a valve inlet 32 which communicates with the pressure region P and a valve exhaust 34 for communicating with the exhaust region E. Figure 4 shows cross section C-C through the lower valve exhaust 34 of the jarring apparatus 10. Figure 5 shows cross section D-D through the lower valve inlet 32 of the jarring apparatus 10.

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 valve inlet 32 and isolated from the 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 valve inlet 32; and an exhaust configuration in which the piston chamber 20b is isolated from the valve inlet 32 and in pressure communication with the 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. 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.

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 Figures 25 and 26).

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.

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.

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.

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.

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 Figure 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 Figure 1).

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.

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.

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.

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.

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.

As described above, the jarring apparatus 10 comprises housing 12 and mandrel 14 mounted within the housing 12, the mandrel 14 and 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.

As shown in Figure 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.

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 later 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.

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.

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.

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.

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 facilitate ease of manufacture and assembly. However, it will be recognised that the mandrel 14 may alternatively comprise a single component.

As shown in Figure 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.

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.

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.

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 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.

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.

As shown in Figures 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. That is, during one phase of relative rotation, the valve inlet defines an open configuration in which pressure communication with the upper piston chamber 20a is permitted and in another phase the valve inlet defines the closed configuration in which pressure communication with the upper piston chamber 20a is prevented, substantially prevented or obturated.

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

As shown in Figures 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.

As shown in Figures 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.

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

As shown in Figures 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.

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.

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

As shown in Figures 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.

As shown in Figures 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.

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

As shown in Figures 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.

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.

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

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 Figure 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.

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.

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, 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.

As shown in Figure 1, movement of the jarring piston 16 in the first axial direction A (to the right as shown in Figure 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 in other embodiments 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.

Referring now to Figure 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.

As shown in Figure 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 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.

Figures 7 to 11 of the accompanying drawings shows the jarring apparatus 10 in a second configuration corresponding to a second phase of rotation. Figure 7 shows a longitudinal sectional view of the apparatus 10 while Figures 8 to 11 respectively show cross-sectional views A-A, B-B, C-C and D-D of the upper valve inlet, upper valve exhaust, lower valve exhaust and lower valve inlet of the jarring apparatus 10.

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 Figure 7 but can be seen in Figure 11). The lower valve exhaust 34 is in the closed configuration.

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.

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 Figure 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.

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 Figure 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 Figure 12.

Referring now to Figure 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.

As shown in Figure 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 10 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 B. As shown in Figure 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.

In the configuration shown in Figure 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.

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.

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.

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.

As shown in Figure 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.

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

As shown in Figure 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.

Also shown in Figure 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 Figure 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.

As shown in Figure 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.

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.

The locking keys 132 are reconfigurable between a radially retracted configuration as shown in Figure 13 and a radially extended configuration.

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.

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.

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 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.

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.

As shown in Figure 13, and referring now also to Figures 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 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 10 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.

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 Figure 15, each operator member 158 comprises a tab 160 which seats in a corresponding recess 162 in the actuator sleeve 1520 and a pin 162 which engages an offset slot 164 in the valve member 150.

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.

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 1/4 turn by movement limiters 172 provided on the seat plates 166.

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.

An upper portion of the actuator sleeve 152 has slots 176, through which are disposed a number of dogs 178. As shown in Figure 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.

As shown in Figure 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.

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.

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.

As shown in Figure 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 200 for offsetting the jarring apparatus 10 from the borehole.

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

As shown in Figure 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 Figure 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.

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.

Referring also to Figure 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.

As can be seen from Figure 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.

Figure 18 of the accompanying drawings shows the jarring apparatus 10 configured to generate a linear down-jar force. As shown in Figure 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.

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

For example, Figures 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.

As shown in Figure 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.

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.

In use, during one phase of relative rotation (as shown in Figure 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 Figure 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.

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.

Figure 24 of the accompanying drawings illustrates part of an alternative jarring apparatus 2010.

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

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. 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 Figure 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 Figure 24). Movement of the jarring piston 2016 and the coupled hammer 3082 generates a jarring force within the jarring apparatus 2010.

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.

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

In use, pressure moves the hammer 2082 against the bias of the spring arrangement 2202. When the valve exhaust 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.

Figure 25 of the accompanying drawings illustrates part of an alternative jarring apparatus 3010.

As shown in Figures 25, the rotary valve arrangement 3022 comprises a lower valve assembly, generally denoted 3026.

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. 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 Figure 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 Figure 25). Movement of the jarring piston 3016 and the coupled hammer 3082 generates a jarring force within the jarring apparatus 3010.

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.

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

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.

Figure 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.

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

As shown in Figure 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.

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

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

As shown in Figure 26, the tool 12 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.

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

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

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.

For example, Figures 27 and 28 of the accompanying drawings diagrammatically show part of an alternative jarring apparatus 5010. Figure 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. Figure 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.

While in examples above, the mandrel is at least partially mounted within the housing, as shown in Figures 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.

Claims

CLAIMS1. A jarring apparatus, comprising: a housing and a mandrel configurable to be rotated relative to each other; a jarring piston mounted within a piston housing to define a piston chamber, wherein the jarring 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 jarring 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 jarring piston to move in the second axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.
The jarring apparatus of claim 1, comprising an axial throughbore.
3. The jarring apparatus of claim 1 or 2, wherein one of the housing and the mandrel defines the valve exhaust.
4. The jarring apparatus of claim 1, 2 or 3, wherein one of the mandrel and the housing defines the valve inlet.
5. The jarring apparatus of any preceding claim, 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.
6. The jarring apparatus of any one of claims 2 to 5, wherein the rotary valve assembly is configured to facilitate selective fluid communication between the valve inlet and the axial throughbore
7. The jarring apparatus of any preceding claim, wherein the mandrel and the housing are configured so as to define an axial flow passage therebetween.
8. The jarring apparatus of claim 7, 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. The jarring apparatus of any preceding claim, wherein the rotary valve assembly forms a first rotary valve assembly of a rotary valve arrangement of the jarring apparatus, and the rotary valve arrangement comprising a second rotary valve assembly.
10. The jarring apparatus of claim 9, 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 jarring piston.
11. The jarring apparatus of claim 9 or 10, wherein the first rotary valve assembly forms a first biasing arrangement of the jarring apparatus and the second rotary assembly forms a second biasing arrangement of the jarring apparatus.
12. The jarring apparatus of any one of claims 1 to 8, wherein the jarring apparatus comprising a single rotary valve assembly in the form of said rotary valve assembly.
13. The jarring apparatus of claim 12, wherein the rotary valve assembly forms a first biasing arrangement of the jarring apparatus and the jarring apparatus comprises a second biasing arrangement.
14. The jarring apparatus of claim 13, wherein the second biasing arrangement comprises a mechanical biasing arrangement.
15. The jarring apparatus of claim 14, wherein the mechanical biasing arrangement comprises or takes the form of a spring arrangement.
16. The jarring apparatus of any preceding claim, wherein the rotary valve assembly comprises at least one rotary valve member which is rotatably fixed to one of the housing and the mandrel.
17. The jarring apparatus of any preceding claim, comprising co-operating impact surfaces, wherein engagement of the impact surfaces results in the jarring force.
18. The jarring apparatus of any preceding claim, wherein the impact surfaces comprise co-operating first and second impact surfaces, the first impact surface being provided on a hammer coupled to or forming part of the jarring piston.
19. The jarring apparatus of any preceding claim, wherein the jarring apparatus is configured so that the impact surfaces do not engage, said movement of the jarring piston itself being sufficient to generate jarring or agitation forces.
20. The jarring apparatus of any one of claims 2 to 19, wherein: the jarring apparatus is configurable in a first, open, configuration which permits access through the axial throughbore, and the jarring apparatus is configurable in a second, obturated, configuration in which access through the jarring 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 jarring apparatus.
21. The jarring apparatus of claim 20, wherein the jarring apparatus comprises, is coupled to or operatively associated with a valve arrangement configured to generate the elevated pressure for use by the jarring 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.
22. The jarring apparatus of claim 21_ wherein the valve arrangement is configured to provide selective fluid communication through the axial throughbore of the jarring apparatus.
23. The jarring apparatus of claim 21 or 22" 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 jarring apparatus, said elevated pressure taking the form of a back pressure.
24. The jarring apparatus of any one of claims 21, 22 or 23, wherein the valve arrangement comprises, is coupled to or operatively associated with an indexer mechanism.
25. The jarring apparatus of claim 24, 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.
26. A tool comprising the jarring apparatus according to any one of claims 1 to 25.
27. The tool of claim 26, wherein the tool comprises a downhole tool.
28. A method for generating jarring 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 jarring 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 jarring piston to move in the second axial direction, wherein movement of the jarring piston in at least one of the first and second axial directions generates a jarring force within the apparatus.
29. A jarring 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.
30. The jarring apparatus of claim 29, 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 jarring mechanism.