WO2022096326A1

WO2022096326A1 - Valve apparatus

Info

Publication number: WO2022096326A1
Application number: PCT/EP2021/079739
Authority: WO
Inventors: Peter Barnes Moyes; Stefan Neil Lewis STEWART
Original assignee: Welleng Science And Technology Ltd
Priority date: 2020-11-04
Filing date: 2021-10-26
Publication date: 2022-05-12
Also published as: GB202017439D0; GB2600703A; GB2600703B

Abstract

A downhole valve apparatus comprises a housing defining a flow path and a valve member mounted within the flow path and being operable between first and second positions to vary flow along the flow path. A mandrel is mounted within the housing and is moveable in reverse first and second directions to operate the valve member to move between its first and second positions, wherein the mandrel is moveable in the first direction by a first actuator to operate the valve member from its first position towards its second position. A second actuator is operable by a trigger pressure differential between the flow path and a region external to the flow path to move the mandrel in the second direction to operate the valve member from its second position to its first position. The valve apparatus further comprises a primary locking system operable on the second actuator and configurable between a locked configuration in which the second actuator is in a non-active state and an unlocked configuration in which the second actuator is in an active state, wherein the primary locking system is configurable between its locked and unlocked configurations by movement of the mandrel in the first direction.

Description

VALVE APPARATUS

FIELD

The present disclosure relates to a valve apparatus for use in downhole applications.

BACKGROUND

Wellbore infrastructure and operations often require the use of valves to provide flow and/or pressure control. For example, valves may be used to control production and/or injection flow rates and pressures, to isolate sections of the wellbore, to contain wellbore pressure and fluids while topside operations are performed, to facilitate pressure testing, to facilitate tool actuation and the like.

In some examples valves may be used within completions to provide initial containment of pressure to facilitate downhole operations, such as to provide pressure testing, actuate other tools, such as pressure-set packers provided along a completion and the like. In this case the completion may have one or more openings which might otherwise prevent pressure containment. The use of a valve may provide temporary isolation of the one or more openings, allowing pressure to be elevated within the completion, which may then be used for setting other tools, testing purposes and the like.

In many cases when the necessary wellbore operations (e.g., testing, tool setting etc.) are completed, the barrier established by the valve should be removed, for example to permit bore access along the completion. There is a clear interest for all operators to utilise wellbore equipment which is robust and reliable, and as such the ability to reliably operate a valve to close/open is of critical importance, especially when any failure may establish a blockage in a completion.

SUMMARY

An aspect of the present disclosure relates to a downhole valve apparatus, comprising: a housing defining a flow path; a valve member mounted within the flow path and being operable between first and second positions to vary flow along the flow path; a mandrel moveable in reverse first and second directions to operate the valve member to move between its first and second positions, wherein the mandrel is moveable in the first direction by a first actuator to operate the valve member from its first position towards its second position; a second actuator operable by a trigger pressure differential between the flow path and a region external to the flow path to move the mandrel in the second direction to operate the valve member from its second position to its first position; and a primary locking system operable on the second actuator and configurable between a locked configuration in which the second actuator is in a non-active state and an unlocked configuration in which the second actuator is in an active state, wherein the primary locking system is configurable between its locked and unlocked configurations by movement of the mandrel in the first direction.

The non-active state of the second actuator may be such that the second actuator is not sensitive to pressure differentials between the flow path and the external region. Similarly, the active state of the second actuator may be such that the second actuator is sensitive to pressure differentials between the flow path and the external region.

Thus, the second actuator may be initially configured in its non-active state by a locking effect provided by the primary locking system. When in this non-active state the second actuator is not sensitive to any pressure differential and as such may be considered to be redundant. Any pressure differential applied may thus have no effect on the second actuator, which may provide a number of advantages. For example, multiple pressure differential events may be accommodated without concern of premature operation of the second actuator, which could otherwise interfere with the desired operation of the valve apparatus. Such pressure differential events may be used for any number of downhole operations, such as setting tools, pressure testing, circulating operations, communication operations and the like. In some examples the valve apparatus may be provided within a wellbore string which is used in fracking operations. In this respect the valve apparatus may be exposed to high and varying pressures during fracking (e.g., in zones below the valve apparatus), which may have minimal effect on the second actuator by virtue of being initially provided in a non- active state.

Further, the initial redundant state of the second actuator may in some examples eliminate requirements for counting mechanisms or similar apparatus which can accommodate one or more pressure differential events without corresponding operation of the second actuator. Such counting mechanisms, or equivalent, may have a limited capability in terms of useable counts. Nevertheless, in some examples a counting mechanism may additionally be used. In this respect, where a counting mechanism is used the redundant state of the second actuator may be such that any pressure differential events do not use up available counts of the counting mechanism.

Also, in some examples the initial redundant state of the second actuator may be such that the second actuator does not resist movement of the mandrel when being moved in the first direction by the first actuator.

When in use, it is only after an initial movement of the mandrel in the first direction, which provides an initial operation of the valve to move to its second position, that the second actuator is brought into an activate state by the reconfiguration of the primary locking system to its unlocked configuration. When in this active state the second actuator becomes sensitive to pressure differentials, such that upon application of the trigger pressure differential the second actuator may move the mandrel in the second direction.

In some examples the apparatus may be configured or operated in such a way that the trigger pressure differential is a first applied pressure differential event following the second actuator being configured in its active state. However, in other examples one or more preceding pressure differential events may be applied prior to application of the trigger pressure differential, wherein the preceding pressure differential event(s) may be accommodated without causing operation of the second actuator while in its active state. In this respect the preceding pressure differential event(s) may be applied as part of a desired downhole operation. In some examples, as will be described in more detail below, a counting apparatus may be used to accommodate the preceding pressure differential event(s). Such a counting apparatus may be configured to accommodate at least one preceding pressure differential event. In some examples one or more preceding pressure differential events may be accommodated via a force release system configured to release the second actuator upon application of a predetermined force. In this respect the predetermined force may be selected such that this will be exceeded upon application of the trigger pressure differential. That is, application of the preceding pressure differential events may not be sufficient to exceed the predetermined force. The second actuator by being operated by the trigger pressure differential may be defined as remotely operated. That is, pressure within one or both the flow path and the external region may be controlled from a remote location, such as a surface location.

The downhole valve apparatus may have multiple applications. In one example the downhole valve apparatus may be used in running completions into a wellbore. In some examples the downhole valve apparatus may be used to provide a temporary pressure barrier downhole, for example to permit internal pressure to be elevated for purposes such as pressure testing, setting tools, such as packers, and/or the like. In examples where the temporary pressure barrier permits the pressure setting of a packer to be achieved, the valve apparatus may be defined as a packer valve. In some examples the valve apparatus may be used to prevent dropped objects passing the valve apparatus. The valve apparatus may function as a deep-set barrier to isolate a subterranean reservoir.

One of the first and second positions of the valve member may comprise an open position, and the other of the first and second positions of the valve member may comprise a closed position. In this respect, the valve member may be initially operated by the first actuator to one of open and close, and subsequently operated by the second actuator to the other of close and open. The particular arrangement or sequence of open/close or close/open may be provided in accordance with a desired application.

In one example, however, the first position of the valve member may comprise an open position. In this respect the valve member may be initially provided in an open position, for example during deployment of the valve apparatus into a wellbore. This initial open position may thus define a run-in-hole (RIH) position. Such an open RIH position may facilitate filling of the valve apparatus and any connected tubing string during deployment into a wellbore.

The second position of the valve member may comprise a closed position, such that an initial movement of the valve member provided by the first actuator may provide closure of the valve member. The closed position of the valve member may facilitate desired downhole operations, such as the pressure setting of downhole tools (e.g., packers), pressure testing, circulating operations, reservoir isolation, and/or the like.

The second actuator may thus be responsible for operating the valve member to subsequently open following its initial closure. As such, the valve apparatus may be configured to be cycled at least open-closed-open. The ability for further operation of the valve apparatus may be optional. The closed configuration of the valve member following initial operation of the mandrel may permit the trigger pressure differential to be developed or achieved. That is, pressure may be developed against the closed valve member, to elevate pressure within the flow path relative to the external region. Furthermore, the use of the second actuator to cause the valve member to again be opened may be such that full bore access is achieved, for example to accommodate flow (e.g., production flow, injection flow etc.) and/or equipment along the flow path and through the valve apparatus.

In alternative examples, the first position of the valve member may comprise a closed position, and the second position may comprise an open position. In this example the apparatus may be configured to be cycled at least closed-open-closed. The ability for further operation of the valve apparatus may be optional.

The downhole valve apparatus may be secured within or along a tubing string for deployment within a wellbore. In this example pressure within the flow path may be defined as tubing pressure. The tubing string may comprise one or more of interconnected tubulars, coiled tubing, tool components, completion equipment and the like. In one example the downhole valve apparatus may form part of a downhole completion. An aspect of the present disclosure may relate to a completion comprising a downhole valve apparatus according to any other aspect.

The region external to the flow path may be at least partially defined within the valve apparatus, for example within a cavity, chamber (e.g., atmospheric chamber or a chamber at any other suitable pressure) or the like within the valve apparatus. In some examples the region external to the flow may be defined by an isolated section of the same flow path, for example on an opposite side of the valve member when the valve member is closed. In some examples the region external to the flow path may be at least partially external to the valve apparatus. For example, when the valve apparatus is deployed within a wellbore the external region may be defined by an annulus region between the valve apparatus and a bore wall (e.g., open bore wall, cased or lined bore wall etc.).

In one example the trigger pressure differential may be defined by a higher pressure within the flow path relative to the external region. Alternatively, the trigger pressure differential may be defined by a higher pressure within the external region relative to the flow path.

The mandrel may be moveable in reverse first and second axial directions to facilitate operation of the valve member. In some examples, the mandrel may alternatively, or additionally, be rotatable in reverse directions.

When the second actuator is in its active state said second actuator may be configured to be moved in response to the trigger pressure differential in the second direction to move the mandrel in the same second direction. In some examples the second actuator may comprise a linear actuator, configured for axial movement in response to the trigger pressure differential. However, in other examples the second actuator may comprise a rotary actuator.

The primary locking system may be configured to provide releasable locking of the second actuator relative to the housing. In this example when the primary locking system is in its locked configuration the second actuator may be held, for example axially held, relative to the housing, and when the primary locking system is in its unlocked configuration the second actuator may be released and permitted to move, for example axially moved, relative to the housing.

The primary locking system may comprise any releasable locking mechanism, such as a latch mechanism, hydraulic locking mechanism, key mechanism, and/or the like.

In one example the primary locking system may comprise a key mechanism. The key mechanism may be configured to provide releasable locking of the second actuator relative to the housing. The key mechanism may comprise a locking key configured to be supported by the mandrel in locking engagement with the second actuator and the housing, wherein movement of the mandrel in the first direction causes the locking key to become unsupported and disengageable from at least one of the second actuator and the housing. In one example, movement of the mandrel in the first direction causes the locking key to become unsupported and disengageable from the second actuator.

The locking key may be radially moveable to become disengaged from at least one of the second actuator and the housing. In this example the locking key may be configured to be radially supported and unsupported by the mandrel, in accordance with movement of the mandrel.

A single locking key may be provided. However, in other examples multiple locking keys may be provided. Such multiple locking keys may be circumferentially and/or axially arranged relative to each other.

One of the second actuator and the housing may define a radial key pocket for receiving the locking key, and the other of the second actuator and housing may define a locking profile (e.g., recess, channel, etc.). Radial movement of the locking key within the key pocket may cause selective engagement and disengagement of the locking key with the locking profile. In this respect when the locking key is supported by the mandrel radial movement of the locking key is prevented, and when the locking key is unsupported by the mandrel such radial movement is permitted.

In one example the housing may define the radial key pocket and the second actuator may define the locking profile.

The second actuator may comprise or define an actuator piston. The second actuator may define an annular actuator piston.

A first axial side of the second actuator may be configured or configurable for pressure communication with the flow path, and an opposite second axial side of the second actuator may be configured or configurable for pressure communication with the external region. In this respect, when the second actuator is in its active state, fluid pressure within the flow path and the external region may bias the second actuator in opposite directions, thus facilitating operation by the presence of any pressure differential between the flow path and external region. The second actuator may be at least partially mounted within an actuator cavity defined within the apparatus. The second actuator may be axially moveable within the actuator cavity. The actuator cavity may define a piston chamber. The actuator cavity may be annular in form.

The actuator cavity may be configured or configurable for pressure communication with the flow path and the external region, such that the second actuator may be pressure operated in accordance with a pressure differential (e.g., the trigger pressure differential) between the flow path and the external region. The actuator cavity may define one or more ports to facilitate pressure communication with one or both of the flow path and the external region. The apparatus may comprise a flow path port for providing pressure communication between the flow path and the cavity. The actuator cavity may comprise an external region port for providing pressure communication between the external region and the cavity.

The second actuator may be configured to seal the external region port after an operation to move the mandrel in the second direction to operate the valve member from its second position to its first position. The second actuator may comprise a sealing arrangement for providing such sealing of the external region port. The sealing arrangement may comprise a sealing nose or plug which is received into the external region port. Such a sealing function may assist to configure the second actuator in a redundant state following an operation to move the mandrel in the second direction to operate the valve member from its second position to its first position. Sealing may be achieved via a metal-to-metal seal between the flowpath and the external region. This may provide a permanent metal-to-metal barrier across the external region port.

The actuator cavity may be defined within or by the housing. The actuator cavity may be defined between inner and outer wall structures of the housing. In this example the inner wall structure may be positioned radially between the mandrel and the second actuator. One or both of the inner and outer wall structures may be generally cylindrical.

The inner wall structure may define a radial key pocket configured to accommodate a locking key, for example in the manner described above, for use in engaging and disengaging the second actuator in accordance with the position/movement of the mandrel.

The outer wall structure of the housing may define an outer wall of the apparatus.

The inner and outer wall structures of the housing may be integrally formed. Alternatively, at least portions of the inner and outer wall structures may be separately formed and secured together. The inner wall structure of the housing may be defined by a sleeve, which may be defined as an actuator sleeve. The actuator sleeve may circumscribe the mandrel. The actuator sleeve may be an integrally formed component of the housing. Alternatively, the actuator sleeve may be provided as a separate housing component and secured to or within the housing, for example via a threaded connection.

The second actuator may extend or protrude from the actuator cavity, for example axially from the actuator cavity. The second actuator may extend from the actuator cavity to facilitate engagement with the mandrel and permit the second actuator to move the mandrel in the second direction.

The apparatus may comprise a drive arrangement for permitting the second actuator, when in its active state, to drivingly engage the mandrel in the second direction. The drive arrangement may comprise an axial drive arrangement, in which axial movement of the second actuator in the second direction causes corresponding axial movement of the mandrel in the second direction.

The drive arrangement may comprise a drive interface provided on the second actuator and a driven interface provided on the mandrel. The drive and driven interfaces may facilitate transmission of a drive force thereacross from the second actuator to the mandrel. The drive and driven interfaces may be axial interfaces for transmitting an axial drive force from the second actuator to the mandrel.

The drive and driven interfaces may be initially separated, for example axially separated, such that an initial separation gap is provided therebetween. Such an initial separation gap may permit the mandrel to be moved in the first direction to operate the valve member from its first position towards its second position without interference from the second actuator. Movement of the mandrel in the first direction may close the separation gap between the drive and driven interfaces. In some examples, when the mandrel is fully stroked in the first direction (e.g., when the valve member is in its second position) the separation gap may be fully closed or substantially fully closed. However, in other examples, when the mandrel is fully stroked in the first direction a residual separation gap may remain between the drive and driven interfaces. Such a residual separation gap may be closed during movement of the second actuator in the second direction to bring the drive and driven interfaces into engagement. In this case the residual separation gap may define or permit a degree of lost motion between the second actuator and the mandrel. Such lost motion may allow movement of the second actuator (e.g., reverse or reciprocating movement) without corresponding movement of the mandrel to facilitate or provide a desired function within the valve, such as to operate a secondary locking system, as will be described in more detail below.

The drive interface on the second actuator may comprise a load shoulder, such as an axial load shoulder. The drive interface may comprise an annular load shoulder. The drive interface may be integrally formed as part of the second actuator.

The drive interface may be rigidly mounted or provided on the second actuator. The driven interface may be rigidly mounted or provided on the mandrel.

The drive arrangement may be configurable into a deactivated state, in which force transmission between the second actuator and the mandrel is prevented. In some examples the ability to deactivate the drive arrangement may permit the mandrel to be moved without interference or restriction from the second actuator. For example, the mandrel may be configured for mechanical manipulation via a further actuator (for example a shifting tool deployed into the valve apparatus) to provide a desired operation of the valve member. Such mechanical manipulation may be provided after the second actuator has shifted the mandrel in its second direction to move the valve member from its second position back to its first position. That is, the mechanical manipulation may be provided to subsequently move the valve member from its first position and again towards its second position. At least one of the drive and driven interfaces may be releasably mounted on the respective second actuator and mandrel to permit the drive arrangement to be deactivated, if required. At least one of the drive and driven interfaces may be releasable upon application of a force thereto above a threshold. The threshold may be non-zero. Such a force may be applied by mechanical manipulation of the mandrel via a further actuator. At least one of the drive and driven interfaces may be releasable via a frangible connection, shearable connection, a latch, and/or the like.

The drive arrangement may be prevented from being deactivated until the second actuator is in a defined position within the apparatus. In one example, the drive arrangement may be prevented from being deactivated until the second actuator has driven the mandrel a predefined distance in the second direction. In this case the predefined distance may be a sufficient distance to ensure the valve member is again in its first position.

In one example the drive interface may be releasably mounted on the second actuator, and the driven interface may be one of rigidly mounted and releasably mounted on the mandrel.

The drive interface may comprise or be formed on a drive key mounted on the second actuator. In one example a plurality of drive keys may be provided, which may be circumferentially arranged around the second actuator. The drive key may be mounted in a radial pocket provided in the second actuator. In one example the drive key may be secured to the second actuator via a connecting pin, such as an axially extending connecting pin. The drive key may be secured to the second actuator via a releasable connector, such as a shearable pin. The releasable connector may be released upon application of a predetermined radial force to permit the drive key to be released from the second actuator, and thus deactivate the drive arrangement. The radial force may be achieved by application of an axial force between the drive and driven interfaces, for example via engaging ramped surfaces. Such an axial force may be applied via a further actuator (e.g., a shifting tool) operating on the mandrel.

The drive key may be radially supported and prevented from being released from the second actuator until the second actuator is in a defined position within the valve apparatus. In one example, the drive key may be prevented from being released until the second actuator has driven the mandrel a predefined distance in the second direction. In this case the predefined distance may a sufficient distance to ensure the valve member is again in its first position. The drive key may be radially captivated between the mandrel and the housing to prevent any radial movement and release of the drive key. Movement of the second actuator in the second direction may move the drive key into alignment with a region of relief, for example in the housing, such that the drive key may be permitted to be moved radially and released from the second actuator.

The driven interface may comprise or be formed on a driven key mounted on the mandrel. In one example a plurality of driven keys may be provided, which may be circumferentially arranged around the mandrel. The driven key may be secured to the mandrel via a releasable connector, such as a shearable pin.

The apparatus may comprise a second actuator latch to prevent movement of the second actuator in the first direction. The second actuator latch may be engaged after the second actuator has travelled a predefined distance in the second direction. Prior to engagement of the second actuator latch the second actuator may be permitted to be moved in reverse first and second directions. Such an arrangement may permit the second actuator to provide a desired function within the apparatus by virtue of being capable of moving in reverse directions, such as to operate a secondary locking system. The second actuator latch, when engaged, may facilitate movement of the second actuator in the second direction while preventing reverse movement in the first direction. The second actuator latch may comprise a ratchet mechanism, for example.

The apparatus may comprise a secondary locking system configurable from a locked configuration in which movement of the second actuator is constrained by the secondary locking system, and an unlocked configuration in which movement of the second actuator is unconstrained by the secondary locking system. The secondary locking system may comprise any releasable locking mechanism, such as a latch mechanism, hydraulic locking mechanism, shearable mechanism, rupture mechanism, key mechanism, and/or the like.

The secondary locking system may be configurable from its locked to unlocked configurations only after the primary locking system is configured in its unlocked configuration. As such, the primary and secondary locking systems are configured to be operated in sequence. The provision of the primary and secondary locking systems may provide a robust arrangement in which the risk of unintentional or premature operation of the second actuator is minimised.

The constrained movement of the second actuator may be such that the second actuator is prevented from moving. Although in this example the second actuator may be prevented from moving, by being in an active state following unlocking of the primary locking system the second actuator may be capable of applying a force on the secondary locking system. Such a force applied by the second actuator may be utilised in the reconfiguring of the secondary locking system from its locked configuration to its unlocked configuration.

The constrained movement of the second actuator may be such that limited movement of the second actuator is permitted. Such limited movement of the second actuator may be utilised in the reconfiguring of the secondary locking system from its locked configuration to its unlocked configuration.

The constrained movement of the second actuator may be such that movement of the second actuator in the second direction is permitted but insufficient to move the mandrel in the second direction (e.g., with a degree of lost motion between the second actuator and the mandrel). In an alternative example the constrained movement of the second actuator may be such that the second actuator may provide limited movement of the mandrel in the second direction. Such limited movement of the mandrel may not be sufficient to cause the valve member to be moved towards its first position.

The unconstrained movement of the second actuator may be such that the second actuator is permitted to move the mandrel in the second direction to cause the valve member to be moved towards its first position.

The secondary locking system may be reconfigured from its locked configuration to its unlocked configuration by operation of the second actuator. In this example the second actuator may be configured, once in its active state, to apply a force or series of forces on the secondary locking system. The force or series of forces applied by the second actuator may be established with or without associated movement of the second actuator. The force or series of forces may originate from one or more pressure differentials applied on the second actuator, for example one or more pressure differentials applied between the flow path and the external region. The one or more pressure differentials may comprise the trigger pressure differential. However, in other examples the one or more pressure differentials may precede the trigger pressure differential. In this example, in use, the trigger pressure differential may be applied after the secondary locking system is configured in its unlocked configuration.

In one example the secondary locking system may be reconfigured from its locked configuration to its unlocked configuration by movement of the second actuator when in its active state. Such movement of the second actuator may comprise movement in a single direction, for example in the second direction. In other examples such movement of the second actuator may comprise a sequence of movements, for example reciprocating movement in the first and second directions.

The secondary locking system may comprise a hydraulic locking mechanism. The secondary locking system may comprise a fluid volume in communication with the second actuator such that movement of the second actuator acts on the fluid volume. The fluid volume may comprise a substantially incompressible fluid, such as hydraulic oil.

The secondary locking system may comprise a fluid release mechanism configured to release or vent the fluid volume and configure the secondary locking system into its unlocked configuration. In this respect, prior to release of the fluid volume said fluid volume may be hydraulically locked between the second actuator and the fluid release mechanism. The fluid release mechanism may be configured to release the fluid volume in accordance with the operation of the second actuator when in its active state.

The fluid release mechanism may comprise a removable barrier. The removable barrier may comprise a rupture element or structure, such as a rupture disc. The removable barrier may comprise a release valve configured to become opened to release the fluid volume. The fluid release mechanism may be configured to release the fluid volume in response to a predetermined release action. The predetermined release action may comprise varying the pressure of the fluid volume. The pressure within the fluid volume may be varied by operation of the second actuator, for example by the second fluid actuator imparting a force on the fluid volume. The predetermined release action may comprise elevating the pressure of the fluid volume, for example above a threshold pressure. The predetermined release action may comprise a pressure cycle of elevating and reducing the pressure of the fluid volume. The predetermined release action may comprise multiple cycles of elevating and reducing the pressure of the fluid volume. The fluid release mechanism may comprise a counter configured to count pressure cycles and permit release of the fluid volume following a predetermined number of pressure cycles (including 1,2, 3... etc.). The counter may comprise a mechanical counter.

The fluid release mechanism may be configured to release or vent the fluid volume relative to one of the flow path and the external region.

The fluid release mechanism may facilitate pressure communication between the second actuator and one of the flow path and the external region. Such pressure communication may be provided before and/or after the fluid volume has been released.

The apparatus may comprise a tertiary locking system configurable from a locked configuration in which movement of the second actuator is constrained, and an unlocked configuration in which movement of the second actuator is unconstrained. The tertiary locking system may be reconfigurable from its locked to unlocked configurations after the secondary locking system is unlocked. The tertiary locking system may comprise a shear arrangement. In one example the shear arrangement may comprise a shearable connection between the second actuator and the housing. The shearable connection may comprise a shearable element mounted in one of the second actuator and the housing, and a track provided in the other of the second actuator and the housing. The shearable element may be configured to run along the track during movement of the second actuator, for example movement to release the secondary locking system. The shearable element may be exposed to a shear force upon reaching a terminating end of the track, such that when a sufficient shear force is applied the shearable connection may shear to unlock the tertiary locking system.

The second actuator may be provided on a second axial side of the valve member. In some examples this second axial side may be an uphole side of the valve member. The first actuator may be operable on the mandrel on a first axial side of the valve member. This first axial side may be a downhole side of the valve member.

The valve member may comprise a ball valve member. In this example the valve member may be rotatable between its first and second positions.

The housing may define a unitary component. Alternatively, the housing may comprise multiple components coupled together. In this respect the housing may be modular. The housing may be defined as a housing assembly. The mandrel may define a unitary component. Alternatively, the mandrel may comprise multiple components coupled together. In this respect the mandrel may be modular. The mandrel may define a mandrel assembly.

The apparatus may comprise a valve operator for engaging the valve member, wherein the valve operator converts movement (e.g., axial movement) of the mandrel to movement (e.g., rotational movement) of the valve member. The valve operator may be coupled to or form part of the mandrel. In this example the mandrel may comprise the valve operator. The valve operator may be rigidly coupled to the mandrel. Such a rigid coupling may be such that movement of the mandrel causes corresponding movement of the valve operator.

The valve operator may comprise an interface mechanism that operatively engages the valve member. The interface mechanism may be configured to convert movement (e.g., axial movement) of the mandrel to movement (e.g., rotational movement) of the valve member. In one example the interface mechanism may comprise a yoke mechanism.

The interface mechanism may be configured to permit a degree of lost motion between the valve operator and the valve member. Such lost motion may permit the mandrel to move in a first movement phase over a first distance without corresponding movement of the valve member, wherein movement of the valve member is caused by movement of the mandrel over a subsequent second movement phase. Such lost motion may permit movement of the mandrel in the first movement phase to provide operation to a secondary system, such as a pressure equalising arrangement, as will be described in more detail below. The lost motion between the valve operator and the valve member may be provided in both the first and second directions of movement of the mandrel.

The valve operator may comprise an interface member. The interface member may comprise an interface structure for operatively engaging the valve member to convert movement of the mandrel and valve operator to desired movement of the valve member. The valve member may comprise a cooperating interface structure for engagement with the interface structure on the interface member. The interface structures on the interface member and the valve member may collectively define at least part of the interface mechanism.

A single interface member may be provided. Alternatively, multiple interface members may be provided. In one example a pair of interface members may be provided, for example on opposite sides, such as diametrically opposite sides, of the valve member.

The interface member may extend axially past the valve member, thus extending between first and second axial sides of the valve member. In examples where the valve operator forms part of the mandrel, the mandrel may thus be considered to extend axially past the valve member. By extending axially past the valve member the mandrel may be arranged to provide an auxiliary operation, such as to operate a pressure equalising arrangement, as will be discussed in more detail below.

The interface member may comprise an elongate member, such as an elongate plate member.

The valve apparatus may comprise a valve seat configured to cooperate with the valve member. The valve seat may function to support the valve member. The valve seat may function to rotatably support the valve member during movement of the valve member between its closed and open positions. The rotary guidance and support provided by the valve seat may minimise or eliminate the requirement for the valve member to include dedicated rotary axis mounts. However, in some examples the valve member may include such rotary axis mounts, such as pivot/rotation pins.

A sealing arrangement may be defined between the valve seat and the valve member for providing a sealed barrier within the flow path when the valve member is in its closed position. The sealing arrangement may comprise or be defined by an interference seal, for example a metal-to-metal seal, between the valve member and the valve seat. The sealing arrangement may comprise one or more sealing members interposed between the valve member and the valve seat. In one example one or more sealing members may be mounted on the valve seat. One or more sealing members may comprise an elastomeric material, PTFE or the like.

The valve seat may be supported by the housing. The valve seat may be integrally formed with the housing. Alternatively, the valve seat may be separately formed from the housing.

The valve seat may be mounted or provided on a sleeve, hereinafter defined as a seat sleeve which is mounted within the housing. In one example the valve seat may be defined or provided on one end of the seat sleeve. The valve seat may be separately formed from the seat sleeve. Alternatively, the valve seat may be integrally formed with the seat sleeve.

The seat sleeve may comprise a unitary component or multiple components. At least a portion of the seat sleeve may be formed separately from the housing. At least a portion of the seat sleeve may be integrally formed with the housing.

The seat sleeve may define a flow path therethrough (e.g., axially therethrough). The flow path of the seat sleeve may define a portion of the flow path of the housing. In such an arrangement the seat sleeve may define a flow sleeve.

The seat sleeve may be moveably mounted within the housing. Such an arrangement may provide a degree of compliance within the valve assembly, for example to absorb any pressure shock loading which may be present within the valve assembly when in use. Furthermore, relative movement between the seat sleeve and the housing may facilitate biasing of the seat sleeve, for example to contribute to an improved seal between the valve seat and the valve member at least when the valve member is in its closed configuration. However, in other examples the seat sleeve may be rigidly fixed within the housing

The seat sleeve may be sealed relative to the housing with a sleeve seal arrangement. The sleeve seal arrangement may comprise one or more seal members, such as O- ring members. The sleeve seal arrangement may comprise or define a dynamic sealing arrangement configured to provide sealing during relative movement between the seat sleeve and the housing. Sealing between the seat sleeve and the housing may permit fluid pressure within the valve apparatus to generate a bias force on the seat sleeve. In one example the seat sleeve may be pressure biased in a direction to engage the valve seat against the valve member. Such an arrangement may assist to increase a sealing effect at least when the valve member is in its closed position and exposed to a pressure differential.

The seat sleeve may define an annular space with the housing. While the space may be defined as being “annular”, the space may not be strictly annular in shape, but may be any shape dictated by the shape of the housing and the seat sleeve and/or alignment therebetween.

The valve apparatus may comprise a guide sleeve which provides support to the valve member. The guide sleeve may be located on an opposite side of the valve member from the seat sleeve. In such an arrangement the valve member may be interposed between the guide sleeve and the seat sleeve. The guide sleeve may define a bearing surface which rotatably supports the valve member.

The guide sleeve may be axially engaged with the housing, for example via a shoulder, no-go profile or the like.

The valve apparatus may comprise a pressure relief arrangement. The pressure relief arrangement may be operable between closed and open configurations to selectively permit pressure communication of the flow path on opposing sides of the valve member when said valve member is in a closed configuration. The pressure relief arrangement may be provided in a closed configuration prior to closing of the valve member. The pressure relief arrangement may be provided in an open configuration prior to opening of the valve member. In this respect, pressure relief or equalisation may be achieved prior to opening of the valve member. This may minimise resistance forces, such as frictional forces, which may otherwise retard opening of the valve member. For example, a large pressure differential may press the valve member against a valve seat, establishing resistance to opening of the valve member. Further, minimising or reducing the pressure differential across the valve member prior to opening may minimise a rapid relief of pressure through the valve member upon opening, which may potentially damage the valve member and/or related features, such as seals and the like.

The pressure relief arrangement may be operated by the mandrel. In this respect, movement of the mandrel may provide operation to both the valve member and the pressure relief arrangement. The apparatus may be configured such that movement of the mandrel provides sequential operation of the pressure relief arrangement and the valve member. Such a configuration may be permitted by the provision of lost motion between the valve member and a valve operator provided on or as part of the mandrel, for example as described above.

The pressure relief arrangement may comprise a bypass flow path extending or defined externally of the flow path. The bypass flow path may be presented in communication with the flow path of the valve apparatus on opposing sides of the valve member when the pressure relief arrangement is in its open configuration. At least a portion of the bypass flow path may be defined between the seat sleeve and the housing (e.g., within the annular space). When the pressure relief arrangement is configured in its open configuration the bypass flow path provides pressure communication between opposing sides of the valve member, such that when the valve member is closed pressure on opposing sides thereof may at least partially equalise.

The pressure relief arrangement may comprise a pressure relief valve assembly operable between closed and open configurations by the actuator assembly. The pressure relief valve assembly may be operable within the bypass flow path.

The pressure relief arrangement may comprise a pressure relief port arranged in communication with one side of the valve member. The pressure relief port may, when the pressure relief arrangement is open, facilitate fluid communication between the flow path of the housing on one side of the valve member and the bypass flow path.

In one example the pressure relief port may be provided on or through the seat sleeve. The pressure relief port may extend through a wall of the seat sleeve.

The pressure relief arrangement may comprise a pressure relief valve member moveable by the mandrel to open (and optionally close) the pressure relief port. The pressure relief valve member may be located between the seat sleeve and the housing (e.g., within the annular space). The pressure relief valve member may comprise a valve sleeve. The pressure relief valve member may be provided on or as part of the mandrel.

The valve apparatus may comprise a force mechanism configured to provide a force on the mandrel. The force mechanism may provide a bias force on the mandrel in the second direction. In this respect, the force mechanism may provide assistance to move the mandrel in the second direction and thus contribute to operate the valve member towards its first position. Movement of the mandrel in the second direction and operation of the valve member towards its first position may thus be provided by a dual actuation effect of the second actuator and the force mechanism.

The force mechanism may define an initial configuration and an energised configuration. The initial configuration may also be defined as a neutral configuration. The force applied by the force mechanism in the second direction may be greater when in the energised configuration than in the initial configuration. The force mechanism may apply a minimal or zero force when in the initial configuration. In other examples, the force mechanism may comprise a pre-load when in the initial configuration.

The force mechanism may comprise a spring arrangement, such as a compression spring, for example a Belleville spring stack. In examples where the force mechanism comprises a spring arrangement, the force mechanism may be configured in its energised configuration by one of applying tension and compression in the spring arrangement. When the force mechanism is in its energised configuration the energy generated therein may be retained by locking the force mechanism relative to the housing. Such an arrangement may be achieved via a latch assembly, such as a latch key assembly. The force mechanism may be released from the housing to permit the force mechanism to apply a force on the mandrel in the second direction.

The force mechanism may be reconfigured from its initial configuration to its energised configuration by movement of the mandrel in the first direction. Such movement of the mandrel in the first direction may apply one of compression and tension to the force mechanism. Thus, movement of the mandrel in the first direction, in addition to operating the valve member to move from its first position towards its second position, also unlocks the primary locking system and energises the force mechanism.

The force mechanism may be energised over an initial movement phase of the mandrel in the first direction. Upon completion of this initial movement phase energy generated within the force mechanism may be retained by locking the force mechanism relative to the housing, for example via a latch assembly as described above. Once the force mechanism becomes locked relative to the housing the mandrel may be permitted to perform a subsequent movement phase in the first direction without any resistance from the force mechanism. Such a subsequent movement phase may allow the mandrel to complete its operation on the valve member to move towards its second position.

The force mechanism may be released from the housing following an initial movement phase of the mandrel in the second direction. This initial movement phase of the mandrel in the second direction may trigger release of a latch assembly. Upon completion of this initial movement phase, the force mechanism may apply a force on the mandrel to provide an assistance force to move the mandrel over a subsequent movement phase in the second direction to complete its operation on the valve member to move towards its first position.

When the second position of the valve member is a closed position, pressure may be elevated within the flow path against the closed valve member. The ability to increase the pressure within the flow path may provide one or more useful functions, such as to set tools and equipment (such as packers), operate a counting device, and the like. The ability to increase pressure within the flow path may also permit the trigger pressure differential to be achieved and to provide a drive force on the second actuator to move the mandrel in the second direction. However, in examples where a pressure relief arrangement provides a pressure equalising effect across the closed valve member prior to opening, the ability to sustain a desired pressure differential may become lost, thus affecting the operation of the second actuator to fully drive the mandrel in the second direction.

The provision of a force mechanism, as described above, may facilitate an ensured drive force on the mandrel in the second direction, accounting for any loss in a pressure drive force by virtue of the pressure relief arrangement becoming opened. However, even where a pressure relief arrangement is not provided, the force mechanism may still be used, for example to provide a force boost to the second actuator.

The first actuator may be provided separately from the valve apparatus. For example, the first actuator may comprise a separate actuator tool, structure or apparatus. However, in other examples the valve apparatus may comprise the first actuator. The first actuator may be provided on an opposite side of the valve member to the second actuator. In this respect, the first and second actuators may operate on opposing axial sides of the valve member

The first actuator may comprise an electrical actuator, for example driven by an electric motor, solenoid or the like. The first actuator may comprise a pressure or hydraulic actuator, for example driven by fluid pressure.

The first actuator may comprise a dropped object, such as a ball, dart etc. In such an example the dropped object may be dropped from surface. The first actuator may comprise a shifting tool, for example a tool deployed and operated from surface.

The first actuator may comprise or define an actuator piston. The first actuator may define an annular actuator piston. The first actuator may be operable in response to a pressure differential applied between the flow path and the external region (e.g., well bore annulus). In this respect, by virtue of the second actuator being initially provided in a non-active state, the application of one or more pressure differentials to operate the first actuator may not have any effect on the second actuator.

In one example, the first actuator may be operated by a pressure differential in which the external region pressure is elevated above the pressure within the flow path, whereas the second actuator may be operated by a pressure differential in which the pressure within the flow path is elevated above the external region pressure. Of course, the opposite arrangement may be provided as an alternative.

A first axial side of the first actuator may be configured or configurable for pressure communication with the flow path, and an opposite second axial side of the first actuator may be configured or configurable for pressure communication with the external region. In this respect, pressure within the flow path and the external region may act on the first actuator in opposite directions, thus facilitating operation by the presence of any pressure differential between the flow path and external region.

The first actuator may be at least partially mounted within a first actuator cavity defined within the apparatus. The first actuator cavity may be defined by an annular space between the housing and a seat sleeve, for example as described above. The first actuator may be provided in the same annular space as the pressure relief valve member of the pressure relief arrangement, which may form part of the mandrel.

The first actuator may be engageable with the mandrel in the first direction, to apply a drive force on the mandrel in the first direction. An axial end face of the first actuator may be configured to engage an adjacent axial end face of the mandrel to apply a drive force therebetween. In some examples where the mandrel comprises a pressure relief valve, the first actuator may be drivingly engage said pressure relief valve in the first direction.

The first actuator may comprise a primary locking system configured to initially lock the first actuator against movement in the first direction. The primary locking system of the first actuator may be configured to be released upon application of a release force in the first direction. The primary locking system of the first actuator may comprise a shear arrangement, such as a shear ring, one or more shear screws, or the like. The primary locking system may comprise a counting mechanism, for example. The first actuator may be moveable in reverse directions (i.e., in the first and second directions). For example, the first actuator may be moveable in reverse directions in response to a reversal in a pressure differential between the flow path and the external region. The first actuator may only be arranged to drive the mandrel in the first direction, whereas reverse movement of the first actuator in the second direction may not cause any corresponding movement of the mandrel. Reverse movement of the first actuator in the second direction may return or retract the first actuator, which may prevent this first actuator from interfering with later movement of the mandrel in the second direction.

Return movement of the first actuator in the second direction may cause any communication path (e.g., a port) between the first actuator and the external region to be sealed. Return movement of the first actuator in the second direction may drive a plug, such as a plunger into a port to seal communication between the external region and the first actuator. This may render the first actuator redundant in that the ability to establish any further pressure differential between the flow path and the external region is eliminated. In some examples the plug may be held in a plugged position by a ratchet assembly or similar locking structure. Sealing may be achieved via a permanent metal-to-metal barrier.

When the first actuator has been returned by reverse movement in the second direction said first actuator may become mechanically locked, for example with respect to the housing. Such mechanical locking may be provided against movement in at least the first direction. Mechanical locking may be provided by a ratchet system, for example.

The first actuator may comprise a priming assembly which initially prevents communication between the first actuator and one of the flow path and the external region. The priming assembly may comprise a priming flow path extending between the first actuator and one of the flow path and the external region, wherein the priming flow path is initially sealed via a priming valve member. The priming valve member may be moveable in response to a trigger pressure event applied between the flow path and the external region. The trigger pressure event may comprise application of a single pressure differential between the flow path and the external region. Alternatively, the trigger pressure event may comprise one or more pressure differential cycles between the flow and the external region. In one example the trigger pressure event may comprise elevating the external region pressure above a threshold pressure. This may release a locking mechanism, such as a shear screw, ring etc. holding the priming valve member against movement. Subsequent to this the external region pressure may be reduced, which may cause the valve member to be moved, for example retracted, to allow the priming flow path to become opened. In this example retraction of the priming valve member may be provided via a spring assembly or stack.

In the examples presented above the movement of the mandrel may be used to operate certain features, such as operate the valve member, unlock the primary locking system, energise a force mechanism, operate a pressure relief arrangement and the like. In other examples the mandrel may be used to operate further tools, systems or apparatus, which may or may not form part of the valve apparatus.

In one example the mandrel may be engaged or engageable with a circulating sub, which may be configured to be selectively opened and closed to provide and prevent circulating flow between the flow path and the external region. Such circulating may be provided to flush an annulus region within an associated well bore, for example. The circulating sub may be provided as a separate assembly. Alternatively, the circulating sub may be considered to form part of the valve apparatus.

The circulating sub may comprise a sub housing, which in some examples may form part of the housing of the valve apparatus. The sub housing may comprise one or more ports, and the circulating sub may comprise a sleeve which is moveable by the mandrel to provide opening and/or closing of the one or more ports in the sub housing.

An aspect of the present disclosure relates to a method for operating a downhole valve apparatus, the method comprising: providing a valve member in a first position; moving a mandrel in a first direction using a first actuator to operate the valve member to move from its first position towards its second position, wherein movement of the mandrel in the first direction unlocks a second actuator to reconfigure the second actuator between an non-active and an active state; and operating the second actuator by a trigger pressure differential between a flow path within the valve apparatus and a region external to the flow path to move the mandrel in the second direction to operate the valve member from its second position to its first position.

The downhole valve apparatus may be provided in accordance with any other aspect.

An aspect of the present disclosure relates to a downhole valve apparatus, comprising: a housing defining a flow path; a valve member mounted within the flow path and being operable between open and closed positions to vary flow along the flow path; a mandrel moveable in reverse first and second directions to operate the valve member to move between its open and closed positions, wherein the mandrel is moveable in the first direction by a first actuator to operate the valve member from its open position towards its closed position; a second actuator operable by a trigger pressure differential between the flow path and a region external to the flow path to move the mandrel in the second direction to operate the valve member from its closed position to its open position; a pressure relief arrangement operable by the mandrel when moved in the second direction such that the pressure relief arrangement is opened before the valve member to provide pressure relief across the valve member prior to being opened; and a force mechanism configured to provide a bias force on the mandrel in the second direction. In this respect, the force mechanism may provide assistance to move the mandrel in the second direction and thus contribute to operate the valve member towards its first position.

The valve apparatus of the present aspect may share features of the valve apparatus of any other aspect. Such features are not repeated for brevity.

Movement of the mandrel in the second direction and operation of the valve member towards its open position may thus be provided by a dual actuation effect of the second actuator and the force mechanism. The force mechanism may define an initial configuration and an energised configuration. The force mechanism may be reconfigured from its initial configuration to its energised configuration by movement of the mandrel in the first direction.

When the valve member is closed pressure may be elevated within the flow path against the closed valve member. The ability to increase the pressure within the flow path may provide one or more useful functions, such as to set tools and equipment (such as packers), operate a counting device, and the like. The ability to increase pressure within the flow path may also permit the trigger pressure differential to be achieved and to provide a drive force on the second actuator to move the mandrel in the second direction. However, as the pressure relief arrangement provides a pressure equalising effect across the closed valve member prior to opening, the ability to sustain a desired pressure differential may become lost, thus affecting the operation of the second actuator to fully drive the mandrel in the second direction.

The provision of a force mechanism, as described above, may facilitate an ensured drive force on the mandrel in the second direction, accounting for any loss in a pressure drive force by virtue of the pressure relief arrangement becoming opened.

An aspect of the present disclosure relates to drive apparatus comprising: a driven member; a drive member; and a drive arrangement interposed between the drive member and the driven member for transmitting an axial drive force from the drive member to the driven member, wherein the drive arrangement comprises a drive interface provided on the drive member and a driven interface provided on the driven member, wherein at least one of the drive and driven interfaces is releasably mounted on the respective drive and driven members to permit the drive arrangement to be deactivated.

At least one of the drive and driven interfaces may be releasable upon application of a force thereto above a threshold. The threshold may be non-zero. At least one of the drive and driven interfaces may be releasable via a frangible connection, shearable connection, a latch, and/or the like. The drive interface may comprise a load shoulder, such as an axial load shoulder. The driven interface may comprise a load shoulder, such as an axial load shoulder.

As defined above, the drive arrangement is configurable into a deactivated state, in which force transmission between the drive member and the driven member is prevented. In some examples the ability to deactivate the drive arrangement may permit the driven member to be moved without interference or restriction from the drive member. For example, the driven member may be configured for mechanical manipulation via a further actuator (for example a shifting tool) to provide a desired operation of the valve member.

The drive arrangement may be prevented from being deactivated until the drive member is in a defined position within the drive apparatus. In one example, the drive arrangement may be prevented from being deactivated until the drive member has driven the driven member a predefined distance in the second direction.

In one example the drive interface may be releasably mounted on the drive member, and the driven interface may be one of rigidly mounted and releasably mounted on the driven member.

The drive interface may comprise or be formed on a drive key mounted on the drive member. In one example a plurality of drive keys may be provided, which may be circumferentially arranged around the drive member. The drive key may be mounted in a radial pocket provided in the drive member. In one example the drive key may be secured to the drive member via a connecting pin, such as an axially extending connecting pin. The drive key may be secured to the drive member via a releasable connector, such as a shearable pin. The releasable connector may be released upon application of a predetermined radial force to permit the drive key to be released from the drive member, and thus deactivate the drive arrangement. The radial force may be achieved by application of an axial force between the drive and driven interfaces, for example via engaging ramped surfaces.

The drive key may be radially supported and prevented from being released from the drive member until the drive member is in a defined position within the drive apparatus. In one example, the drive key may be prevented from being released until the drive member has driven the driven member a predefined distance in the second direction. The drive key may be radially captivated between the driven member and a radial support surface to prevent any radial movement and release of the drive key. The radial support surface may be provided on a sleeve member, such as a housing of the drive apparatus. Movement of the drive member may move the drive key into alignment with a region of relief such that the drive key may be permitted to be moved radially and released from the drive member.

The driven interface may comprise or be formed on a driven key mounted on the driven member. In one example a plurality of driven keys may be provided, which may be circumferentially arranged around the driven member. The driven key may be secured to the driven member via a releasable connector, such as a shearable pin.

In an alternative example the driven interface may be releasably mounted on the driven member, and the drive interface may be one of rigidly mounted and releasably mounted on the drive member.

The drive member may be circular in form, for example annular in form. The drive member may comprise an actuator, such as a hydraulic actuator. The drive member may comprise or be secured to a piston.

The driven member may be circular in form, for example annular in form. The driven member may comprise a sleeve. The driven member may comprise a mandrel.

At least one of the drive and driven members may comprise a unitary component. At least one of the drive and driven members may comprise multiple components.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the present disclosure will now be provided, by way of example only, with reference to the accompanying Figures, in which:

Figures 1A to 1G diagrammatically illustrate a sequence of operation of an example downhole valve apparatus; Figure 2A provides a simplified illustration of an outline of an example downhole valve apparatus, showing this apparatus divided into multiple portions to provide a reference guide for enlarged divided views of Figures 2B, 2C, 2E, 2F, 2H and 2I;

Figures 2B to 2I provide enlarged views of portions or regions of the downhole valve as shown in split outline in Figure 2A;

Figure 3A is a global sectional view of the valve apparatus of Figure 2;

Figure 3B is an enlarged view of region 3B of Figure 3A;

Figure 4A is a global sectional view of the valve apparatus of Figure 2;

Figures 4B, 4C and 4D are enlarged views of regions 4B, 4C and 4D, respectively, of Figure 4A;

Figure 5A is a global sectional view of the valve apparatus of Figure 2;

Figures 5B and 5C are enlarged views of regions 5B and 5C, respectively, of Figure 5A;

Figure 6A is a global sectional view of the valve apparatus of Figure 2;

Figure 6B is an enlarged view of region 6B of Figure 6A;

Figure 7A is a global sectional view of the valve apparatus of Figure 2;

Figure 7B is an enlarged view of region 7B of Figure 7A;

Figure 7C is an enlarged view of region 7C of Figure 7B;

Figure 8A is a global sectional view of the valve apparatus of Figure 2;

Figure 8B is an enlarged view of region 8B of Figure 8A; Figure 9A is a global sectional view of the valve apparatus of Figure 2;

Figure 9B is an enlarged view of region 9B of Figure 9A;

Figure 10A is a global sectional view of the valve apparatus of Figure 2;

Figure 10B is an enlarged view of region 10B of Figure 10A;

Figure 11 A is a global sectional view of the valve apparatus of Figure 2;

Figure 11 B is an enlarged view of region 11 B of Figure 11 A;

Figure 12A is a global sectional view of the valve apparatus of Figure 2;

Figure 12B is an enlarged view of region 12B of Figure 12A;

Figure 13A is a global sectional view of the valve apparatus of Figure 2;

Figure 13B is an enlarged view of region 13B of Figure 13A;

Figure 14A is a global sectional view of the valve apparatus of Figure 2;

Figures 14B and 14C are enlarged views of regions 14B and 14C, respectively, of Figure 14A;

Figure 15A is a global sectional view of the valve apparatus of Figure 2;

Figures 15B and 15D are enlarged views of region 15B/D of Figure 15A, with the apparatus shown in different configurations;

Figures 15C and 15E are enlarged views of region 15C/E of Figure 15A, with the apparatus shown in different configurations; and

Figure 15F is an enlarged view of region 15F of Figure 15A. DETAILED DESCRIPTION OF THE DRAWINGS

The present disclosure provides details of a downhole valve apparatus and associated methods of operation. The downhole valve apparatus may be used to vary flow and/or pressure along a flow path in a wellbore, or the like. The valve apparatus may have any number of uses, such as in the deployment of equipment (e.g., completion equipment), as a temporary or permanent pressure/flow barrier, and the like. In some examples that follow a valve apparatus is illustrated in use in the deployment of some completion equipment into a wellbore.

The downhole valve apparatus may include multiple features and functions, many of which may be considered optional. For example, as will be described in more detail below an example valve apparatus provides for operation of a valve member using movement of a mandrel. In some cases, the mandrel may only be used to operate the valve member. However, in other examples, the mandrel may operate other optional tools, features, equipment etc., such as circulating tools, pressure relief systems and the like.

An example of a downhole valve apparatus, generally identified by reference numeral 10, will now be described with reference to Figures 1A to 1G, which diagrammatically illustrate a sequence of operation of the valve apparatus 10 when deployed in a wellbore 12, which may be cased/lined or open hole.

The valve apparatus 10 is illustrated in Figure 1A in its initial run-in-hole (RIH) configuration, and includes a housing assembly 14 which defines an internal flow path 16 with a ball valve member 18 mounted therein, wherein the ball valve member 18 is initially open in the illustrated RIH configuration. The valve apparatus 10 further includes a mandrel assembly 20 which, as will described in more detail below, is moveable in a first axial direction (illustrated by arrow 22) by a first actuator 24 to cause the valve member 18 to be closed, and subsequently moveable in a reverse second axial direction (illustrated by arrow 26) by a second actuator 28 to again open the valve member 18.

In the present example, the first actuator 24 is provided as part of the valve apparatus 10. However, this need not be the case, and instead the first actuator may be provided as a separate integer, for example as part of a separate tool, such as a shifting tool. In the present example, the first actuator 24 is hydraulically operated in accordance with a pressure differential applied between the flow path 16 and a wellbore annulus region 30. However, in the initial RIH configuration the first actuator 24 is isolated from annulus pressure (illustrated via broken line 32) via a first actuator mechanism 34 which must first be triggered before the first actuator 24 may be operated, which will be described in detail below.

The second actuator 28, in the present example, is also hydraulically operated in accordance with a pressure differential applied between the flow path 16 and a wellbore annulus region 30. However, when in the illustrated RIH configuration the second actuator 28 is locked relative to the housing 14 via a primary locking system 36 such that the second actuator is in a non-active state and not sensitive to pressure differentials between the flow path 16 and the annulus 30. Thus, any pressure differential applied may have no effect on the second actuator 28, which may provide a number of advantages. For example, multiple pressure differential events may be accommodated without concern of premature operation of the second actuator 28, which could otherwise interfere with the desired operation of the valve apparatus 10. Such pressure differential events may be used for any number of downhole operations, such as setting tools, pressure testing, circulating operations, communication operations and the like.

As will be described in detail below, the primary locking system 36 is configured to become unlocked to release the second actuator from the housing 14 by movement of the mandrel 20 in the first direction 22. In this respect, once the primary locking system 36 is unlocked, the second actuator 28 may be configured in an active state and sensitive to pressure differentials between the flow path 16 and the annulus 30.

The valve apparatus 10 further includes an optional secondary locking system 38 configurable from a locked configuration in which movement of the second actuator 28 is constrained (e.g., prevented or limited) and an unlocked configuration in which movement of the second actuator 28 is unconstrained. The secondary locking system 38 may be configurable from its locked to unlocked configurations only after the primary locking system 36 is configured in its unlocked configuration. As such, the primary and secondary locking systems 36, 38 are configured to be operated in sequence. The provision of the primary and secondary locking systems 36, 38 may provide a robust arrangement in which the risk of unintentional or premature operation of the second actuator 28 is minimised.

The secondary locking system 38 may be reconfigured from its locked configuration to its unlocked configuration by operation of the second actuator 28. In this example, the second actuator 28 may be configured, once in its active state, to apply a force or series of forces on the secondary locking system 38. The force or series of forces may originate from one or more pressure differentials applied on the second actuator 28, for example one or more pressure differentials applied between the flow path 16 and the annulus 30.

The secondary locking system 38 in the present example comprises a second actuator mechanism 40, wherein a substantially incompressible fluid volume is initially trapped between the second actuator 28 and the second actuator mechanism 40, as illustrated by dashed line 42. This trapped fluid volume 42 may define a hydraulic lock, preventing or restricting full operation of the second actuator 28. The second actuator mechanism 40 may be or comprise a fluid release mechanism configured to release or vent the fluid volume 42 to the annulus 30 and configure the secondary locking system 40 into its unlocked configuration. In some examples, the fluid release mechanism may comprise a burst disc or similar mechanism, a counter mechanism and/or the like.

The valve apparatus 10 further comprises an optional force mechanism 44 which, in use, provides a boost force to the mandrel 20 in the second direction 26. When in the illustrated RIH configuration the force mechanism 44 is in a neutral condition (which may include zero load, or a degree of pre-load). As will be described in more detail below, movement of the mandrel 20 in the first direction 22 to close the valve member 18 energises the force mechanism 44, in preparation to apply a boost force to the mandrel 20 in the second direction 26 to assist in the re-opening of the valve member 18.

The valve apparatus 10 further comprises an optional circulating sub 46 which, in use, permits circulating flow between the flow path 16 and the annulus, for example to flush the annulus 30. In the illustrated RIH position, the circulating sub 46 is in a locked closed configuration, such that any circulation between the flow path 16 and the annulus 30 via the circulating sub 46 is prevented. As will be described in more detail below, movement of the mandrel 20 in the first direction 22 causes the circulating sub 46 to become unlocked.

The valve apparatus 10 also comprises an optional pressure relief arrangement 48 which, in use, provides for pressure equalisation across the valve member 18, when closed, such that the valve member 18 may be subsequently opened without being under any or excessive pressure differential, which may not be desirable.

The valve apparatus 10 is illustrated in Figure 1A deployed in combination with a lower tool string 48 (which may or may not form part of the valve apparatus 10), wherein the lower tool string includes a lower packer assembly 50, shown in a set configuration, and an orifice 52 which may form part of a further actuator mechanism. The valve apparatus is also shown deployed in combination with an upper packer assembly 54, shown in an un-set configuration, wherein the upper packer assembly 54 may or may not form part of the valve apparatus 10. Further, the valve apparatus 10 may alternatively, or additionally, be deployed into the wellbore 12 in combination with other downhole tools or equipment, such as other completion equipment, bridge plugs, straddles, slip systems, sleeve valves etc.

A sequence of operation of the valve apparatus 10 will now be described, referring initially still to Figure 1A. With the lower packer 50 set fluid is circulated down the annulus 30 (illustrated by arrows 56), through orifice 52 (illustrated by arrow 58) and upwardly through the flow path 16 towards surface (illustrated by arrow 60). An internal barrier (not illustrated) may be set below the valve apparatus 10 to confine the return flow upwardly toward surface. Appropriate control of the flow rate, in combination with the flow restriction effect of the orifice 52, will generate a backpressure within the annulus 30, thus establishing a pressure differential between the annulus 30 and the flow path 16, with the annulus pressure being elevated above the flow path pressure. In the following description, as the flow path 16 forms part of a tubing string, any pressure within the flow path 16 will be defined as tubing pressure. The generated pressure differential, upon reaching a threshold value, will activate the first actuator mechanism 34, thus exposing the first actuator 24 to annulus pressure, as illustrated in Figure 1B. The first actuator 24, now in response to the applied pressure differential, drives the mandrel 20 in the first direction 22 to cause the valve member 18 to rotate towards its closed position. Flow along the annulus 30 in the direction of arrows 56 may continue until no returns can be seen at surface, providing an indication that the valve member 18 has closed. Other indicators may also be provided, such as a spike in annulus pressure, and/or the like.

Movement of the mandrel 20 in the first direction also provides or facilitates a number of other operations, including unlocking the primary locking system 36 and thus configuring the second actuator 28 in its active state and sensitive to pressure differentials between the flow path 16 and annulus 30. However, in the configuration of Figure 1B the secondary locking system 38 remains in a locked configuration, such that movement of the second actuator 28 is still constrained. Movement of the mandrel 20 in the first direction 22 also energises the force mechanism 44 and unlocks the circulating sub 46. In this respect, a single actuation event of the mandrel 20 being moved in the first direction 22 provides operation to a number of elements of the valve apparatus 10.

In some applications an operator may, at this stage, wish to apply pressure testing relative to the closed valve member 18, for example to pressure test above and/or below the valve member 18. Such pressure testing may be performed to test individual connectors and the like. As will be described in detail below, the upper packer assembly 54 is configured to be pressure set and as such any pressure testing at this stage may be performed below any pressure threshold value for setting the upper packer assembly 54.

In a subsequent operation, shown in Figure 1C, the annulus pressure is elevated above tubing pressure, with the resulting annulus/tubing pressure differential causing the circulating sub 46, which was unlocked in the previous step, to be opened and establish a circulation path 62 between the annulus 30 and flow path 16 above the closed valve member 18. The circulation path 62 may permit drilling fluid, for example, to be reverse circulated out and replaced with, for example, a desired completion fluid.

Figure 1D illustrates a subsequent operational step in which tubing pressure is elevated above annulus pressure, generating a tubing/annulus pressure differential which causes the circulating sub 46 to be closed and the upper packer assembly 54 to be pressure set. Any pressure trapped in the annulus between the upper and lower packers 54, 50 may be relieved into the flow path 16 via the circulating sub 46.

The tubing/annulus pressure differential may also be used to operate other tools etc. provided uphole of the valve apparatus 10. During this step illustrated in Figure 1D, the tubing/annulus pressure differential also acts on the first actuator 24 (with tubing pressure bypassing the closed valve member 18 via a sealed bypass passage), causing the first actuator 24 to be returned to its initial position, and at the same time sealing off any further communication with the annulus, thus rendering the first actuator 24 redundant. The set packer 54 may be appropriately pressure tested in accordance with any desired operator protocols.

When it is desired to re-open the valve apparatus 10 tubing pressure may be further elevated, increasing the tubing/annulus pressure differential, causing the secondary locking system 38 to become unlocked, as illustrated in Figure 1 E. Such unlocking may be achieved by opening the second actuator mechanism 40 to the annulus 30, thus allowing venting of the fluid volume 42, removing the hydraulic lock.

As illustrated in Figure 1F, with the secondary locking system 40 now unlocked, the tubing/annulus pressure differential causes the second actuator 28 to drive the mandrel 20 in the second direction 26, with the assistance of the force mechanism 44. Such movement of the mandrel 20 initially operates the pressure relief arrangement 48, allowing pressure to equalise on opposite sides of the closed valve member 18. Such pressure equalisation may thus eliminate or restrict the ability to retain the tubing/annulus pressure differential, which may result in a loss in the fluid drive on the second actuator 28. The force mechanism 44 may thus compensate for this loss in fluid drive, providing continued movement of the mandrel 20 in the second direction 26 to cause the valve member 18 to be re-opened, as illustrated in Figure 1G.

When the valve member 18 is fully re-opened, the second actuator 28 may become locked against any further movement, effectively becoming redundant. In this respect, any subsequent operation of the valve apparatus may either be prevented, or alternatively may be possible through manual intervention and shifting (e.g., via a deployed shifting tool) of the mandrel 20. A more detailed example of a downhole valve apparatus, generally identified by reference numeral 100, will now be described with reference initially to Figures 2A to 2I. Many of the features and operation of the valve apparatus 100 are similar in many respects to the valve apparatus 10 described above. As such, the detail presented above in relation to valve apparatus 10 provides useful background, which should assist in the understanding of the now described valve apparatus 100.

Figure 2A provides a simplified illustration of an outline of the valve apparatus 100 divided into multiple portions to provide a reference guide for the general location of the enlarged divided views of Figures 2B, 2C, 2E, 2F, 2H and 2I. In this respect, Figure 2B represents one end region of the apparatus 10, whereas Figure 2I represents an opposite end region, with Figures 2C to 2G illustrating details of individual regions therebetween.

As illustrated in Figure 2B the valve apparatus 100 includes a housing 102 defining a flow path 104 therein. As will be apparent from the drawings the housing 102 is composed of multiple interconnected parts or modules such that the housing 102 may be defined as a housing assembly. The housing 102 defines a lower connector 106 which facilitates connection of the valve apparatus 100 to other equipment, such as a tubing string, other tools etc.

A first actuator mechanism 108 is mounted externally of the housing 102 and is configured to perform a similar function to the first actuator mechanism 34 of valve apparatus 10. In this example, the first actuator mechanism 102 includes a first port 110 which is in pressure communication with an activator line 112 which applies an activation pressure to the actuator mechanism 114 from a further tool or mechanism (not illustrated). The first actuator mechanism further includes a second port 114 which is open to the external environment, which in use will be a wellbore annulus 116. A third port 118 is provided and in communication with a first actuator 120 (Figure 2C) via a delivery conduit 122. With brief reference to Figure 2C, delivery conduit 122 is secured to port 123 within the housing 102. It should be noted that other ports 123a are provided (one other port 123a illustrated in Figure 2C). These ports 123a are used during initial filling (e.g., with grease, hydraulic fluid etc.) prior to deployment, and will be subsequently plugged prior to deployment. Referring again to Figure 2B, the first actuator mechanism 108 includes a valve rod 124 which initially seals a flow path 126 between the second and third ports 114, 118, thus preventing communication of annulus pressure to the first actuator 120. Following a predefined cycle of activation pressure, which in the present example may comprise a single cycle of increasing and decreasing activation pressure, the valve rod 124 will move to open the flow path 126, thus establishing pressure communication between the annulus 116 and the first actuator 120.

As will be described in more detail below, when the first actuator mechanism 108 has been triggered, the first actuator 120 may then be operated in accordance with a pressure differential between the annulus 116 and the flow path 104, wherein the pressure within the flow path 104 may be defined as tubing pressure.

With reference to Figure 2C, the valve apparatus 100 further includes a ball valve member 124 which is initially open, and a mandrel 126 which extends axially through the housing 102 from a first or lower end 128, to a second or upper end 130 (Figure 2I). As will be apparent from the drawings, the mandrel 126 is composed of multiple interconnected parts or modules such that the mandrel may be defined as a mandrel assembly. The mandrel 126 is axially moveable within the housing in reverse first and second directions 22, 26 to operate the valve member 124 to be closed and subsequently opened. Axial movement of the mandrel 126 also provides multiple other functions.

The valve apparatus 100 further includes a seat sleeve 132 that includes a valve seat 134 which cooperates with the valve member 124 to provide sealing therewith when closed. The valve seat 134 also functions to rotatably support the valve member 124 during movement of the valve member between its closed and open positions. The seat sleeve 132 is mounted on a sprung sleeve assembly 138 (Figure 2B) which functions to bias the seat sleeve 132 and valve seat 134 into engagement with the valve member 124. The seat sleeve 132 is also sealed relative to the housing 102 via a seal assembly 140 (also Figure 2B).

The seat sleeve 132 defines an annular space 142 with the housing 102, wherein this annular space accommodates a lower end region of the mandrel 126 and the first actuator 120. The mandrel 126 comprises a valve member interface 70 which includes a pair of diametrically opposed valve plates 72 which extend axially past the valve member 124. The valve plates 72 engage with the valve member 124 in such a way (for example via a yoke mechanism, cam mechanism etc.) that axial movement of the mandrel 126 is translated to rotational movement of the valve member 124. Furthermore, the valve plates 72 permit a degree of lost motion between the mandrel 126 and the valve member 124. That is, the mandrel 126 may be moved in the first axial direction 22 over an axial distance before rotation of the valve member 124 towards its closed position is initiated. Conversely, when the valve member 124 is closed, the mandrel may be moved in the second axial direction 26 over an axial distance before rotation of the valve member 124 towards its open position is initiated. In other examples a more rigid interface may be provided between the valve plates 72 and the mandrel 126, such that lost motion is minimal or non-existent.

The valve apparatus 100 further comprises an optional pressure relief arrangement 74 which functions to provide pressure equalisation across the valve member 124 prior to being opened. The pressure relief arrangement comprises a plurality of circumferentially arranged relief ports 76 extending radially through the seat sleeve 132, and a pressure relief sleeve valve 78 which is mounted on the mandrel 126. In this respect, the pressure relief sleeve valve 78 may be considered to form part of the mandrel 126. In the illustrated initial configuration the pressure relief sleeve valve 78 is positioned such that the relief ports 76 are not occluded and thus open. Movement of the mandrel 126 in the first direction 22 will cause the pressure relief sleeve valve 78 to be moved to close the relief ports 76. By virtue of the lost motion provided between the valve member interface 70 and the valve member 124, the relief ports 76 are closed prior to the valve member 124. Conversely, starting from a valve closed position, the lost motion is such that movement of the mandrel 126 in the second direction 26 will cause the pressure relief sleeve valve 78 to be moved to open the relief ports 76 prior to opening of the valve member 124. As such, pressure may be equalised on either side of the still closed valve member 124 via the relief ports 76.

The first actuator 120 is illustrated in Figure 2D, which is an enlarged view of region 2D of Figure 2C. As noted, the first actuator 120 is mounted in the annular space 142 between the housing 102 and the seat sleeve 132. The first actuator 120 includes an annular piston assembly 144 which includes a piston body 146 which carries an inner seal 148 for sealing engagement with the seat sleeve 132, and an outer seal 150 for sealing engagement with the housing 102. In use, a first side 152 of the piston assembly 144 is exposed to tubing pressure, whereas a second side 154 is exposed to annulus pressure, following triggering of the first actuator mechanism 108 described above. As such, the annular piston assembly 144 may be moveable in response to any pressure differential applied. Specifically, where the annulus pressure dominates (referred to as an annulus/tubing pressure differential) the piston assembly 144 will be biased in the first axial direction 22, and when the tubing pressure dominates (referred to as a tubing/annulus pressure differential) the piston assembly 144 will be biased in the second axial direction 26.

The first actuator 120 further includes a ratchet module 156 which is initially axially secured to the piston assembly 144 via a shear ring 176. The ratchet module 156 includes a lower ratchet box or sleeve 158 which includes a ratchet profile 160 on an inner surface thereof, and is in engagement with a corresponding ratchet profile 162 on an inner sleeve 164 which is secured to the housing 102. The ratchet profiles 160, 162 are arranged such that the ratchet module 156 may move relative to the housing 102 in the second direction 26, but is prevented from movement in the first direction 22.

The ratchet module 156 further includes an upper ratchet box 166 in the form of an axially captivated split ring which includes a ratchet profile 168 on an inner surface thereof. The piston assembly 144 includes a ratchet pin or nose 170 which includes a ratchet profile 172 on an outer surface thereof, and in the illustrated initial configuration extends axially into the upper ratchet box 166. However, the ratchet module 156 further includes a split ring spacer 174 which is initially radially interposed between the upper ratchet box 166 and the ratchet pin 170 of the piston assembly 144, thus preventing any engagement of the respective ratchet profiles 168, 172.

An annulus pressure delivery bore 177 extends axially through the inner housing sleeve 164 and is arranged in fluid communication with delivery conduit 122 which extends to the first actuator mechanism (see Figures 2B and 2C). The delivery bore 177 opens into the annular space 142 and includes a plug seat 178 at its open end. The first actuator 120 further includes a plug plunger 180 which is initially separated from the plug seat 178 in the illustrated initial configuration, such that communication between the first actuator mechanism 108 and the annular space 142 is permitted. The plug plunger 180 includes a shear assembly 182 which initially provides separation between the plug 180 and plug seat 178.

When in the illustrated initial configuration the first actuator 120 is axially separated and disengaged from the lower end face 128 of the mandrel 126 (i.e., the pressure relief sleeve valve 78). During use, as will be described in more detail below, the piston assembly 144 of the first actuator 120 is driven by an annulus/tubing differential pressure to become engaged with the lower end face 128 of the mandrel 126 to provide an axial driving force thereto in the first direction 22.

It should be noted that the first actuator 120 may be used independently in any other apparatus, and is not exclusively for use in the present described valve apparatus 100. In this respect, an aspect of the present disclosure relates to the first actuator for use in providing actuation to any other object or apparatus.

Reference is now made to Figures 2E and 2F which illustrate regions of the valve apparatus 100 which include a second actuator 190 (which traverses Figures 2E and 2F), a primary locking system 192, a secondary locking system 194 including a second actuator mechanism 196, and a force mechanism 198. Both the housing 102 and the mandrel 126 extend along the entire extent of the regions of the apparatus 100 illustrated in Figures 2E and 2F.

It should be noted that the second actuator 190 may be used independently in any other apparatus, and is not exclusively for use in the present described valve apparatus 100. this respect, an aspect of the present disclosure relates to the second actuator for use in providing actuation to any other object or apparatus.

An enlarged view of the second actuator 190 and primary locking system 192 is shown in Figure 2G, which represents region 2G of Figures 2E and 2G. The second actuator 190 includes an annular piston module 200 which is positioned in an annular space 202 defined between the housing 102 and a piston sleeve 204, wherein the piston sleeve 204 is connected with the housing 102 via a threaded connector 206 (Figure 2E). The piston module 200 includes a piston body 208 which carries an inner seal 210 for sealing engagement with the piston sleeve 208, and an outer seal 212 for sealing engagement with the housing 102. In use, a first side 214 of the piston module 200 is exposed to tubing pressure, whereas a second side 216 is exposed to annulus pressure, following triggering of the second actuator mechanism 196, described later. In a desired operation, when the second actuator module 190 is unlocked, an applied tubing/annulus pressure differential will cause the piston module 200 to be driven in the second axial direction 26.

The piston body 208 includes a sealing nose 218 located towards the second side 216, and as will be described in more detail below this sealing nose 218 functions to eventually prevent communication between the annulus 116 surrounding the apparatus 100 and the annular space 202.

The second actuator 190 further includes a drive module 220 which is axially secured to the piston module 200 (specifically to the piston body 208) via a link sleeve 222 and a piston shear sleeve 224. The drive module 220 includes a plurality of circumferentially arranged drive keys 226 (only one illustrated in Figure 2G) mounted in respective radial slots 228 in a key sub 230, wherein the keys 226 are secured in place using respective axial shear screws 232. In the illustrated configuration the drive keys 226 have a radial thickness that substantially corresponds to the annular space between the housing 102 and the mandrel 126.

Each drive key 226 includes a drive interface 234 configured to drivingly engage a corresponding driven interface 236 provided on the mandrel 126, wherein in the illustrated initial configuration the drive and driven interfaces 234, 236 are axially separated. In use, when the drive and driven interfaces 234, 236 are axially engaged, movement of the second actuator 190 in the second direction 26 will cause corresponding axial movement of the mandrel 126.

The drive module 220 also includes a ratchet ring 238 which is configured to engage ratchet retainer sleeve 240 secured to the housing 102 once the second actuator 190 has moved a sufficient axial distance in the second direction 26. Once the ratchet ring 238 and ratchet retainer sleeve 240 are engaged, return movement of the second actuator 190 in the first direction will be prevented. The drive module 220 may be used in any other application or apparatus, and is not exclusively for use in the example valve apparatus 100 currently disclosed. In this respect, the drive module may be associated with any drive member (and not exclusively a piston), and any driven member (and not exclusively a mandrel). As such, an aspect of the present disclosure relates to a drive apparatus.

As noted above, the drive module 220 is connected to the piston module 220 via a link sleeve 22 and a piston shear sleeve 224. The piston shear sleeve 224 carries a plurality of circumferentially arranged shear pins 242 (only one illustrated in Figure 2G). The shear pins 242 extend radially inwardly and are received in respective shear pin tracks 244 formed in the piston sleeve 204 (although a single annular recess may be provided instead of multiple individual tracks 244), which as noted above is secured relative to the housing 102. In the illustrated initial configuration the shear pins 242 are located at one side of the respective tracks 244, such that a degree of movement of the second actuator 190 in the second axial direction 26 is permitted before the pins 242 engage the opposite end of the tracks 244, which will be described in more detail below.

The primary locking system 192 is formed between a number of elements of the valve apparatus 100, including the piston sleeve 204 (and thus the housing 102), the mandrel 126 and the second actuator 190. In this respect the primary locking system 192 includes a plurality of circumferentially arranged locking keys 246 (only one shown in Figure 2G) which extend through respective radial slots 248 in the piston sleeve 204. In the illustrated initial configuration the locking keys 246 are received within respective locking recesses 250 (or a single annular recess) formed in the second actuator 190. The mandrel 126 radially supports the locking keys 246 in engagement with the locking recesses 250, thus providing the primary locking system 192 in a locked configuration in which the second actuator 190 is mechanically locked relative to the housing 102. As such, the second actuator 190 may be considered to be in a non-active state and not sensitive to any pressure differentials.

The mandrel 126 includes a region of reduced outer diameter, which may be defined as an unlocking region 252. When the mandrel 126 is moved in the first direction 22 the unlocking region 252 will become axially aligned with the locking keys 246 to allow these keys 246 to be disengaged from the respective locking recesses 250, thus configuring the primary locking system 192 in an unlocked configuration and rendering the second actuator 190 in an active state.

Referring again to Figure 2E, details of the secondary locking system 194 will now be described. The second actuator mechanism 196 of the secondary locking system 194 includes an annulus port 260 which is in communication with the wellbore annulus 116, and an internal port 262 which is in communication with the annular space 202 provided between the piston sleeve 204 and the housing 102. A flow path is provided between the annulus and internal ports 260, 262, wherein the second actuator mechanism 196 includes a valve rod 264 which initially seals this flow path, such that the second actuator mechanism 196 may be initially closed.

A hydraulic fluid 264 fills the space between the second actuator 190 and the closed second actuator mechanism 196, thus constraining movement of the second actuator 190 (when the primary locking system 192 is unlocked) via a hydraulic locking effect. A balance piston assembly 265 is provided to accommodate thermal expansion of the hydraulic fluid 264. This hydraulic lock may be released upon opening or activation of the second actuator mechanism 196, which allows the hydraulic fluid 264 to be vented to the annulus 116. In the present example the second actuator mechanism 196 may become opened following a predefined activation sequence involving a cycle of increasing and decreasing tubing pressures. In this respect the effect of increasing and decreasing tubing pressure may be transmitted to the second actuator mechanism 196 via the second actuator 190 and the hydraulic fluid. This predefined activation cycle may function to cause the rod valve 264 of the second actuator mechanism 264 to open the flow path and permit the hydraulic fluid 264 to be vented.

Referring again to Figure 2F, details of the force mechanism 198 will now be described. The force mechanism 198 includes a Belleville spring stack 270 mounted radially between the housing 102 and the mandrel 126, and extending axially between a spring face 272 of the housing 102 and a spring key sleeve 274. The spring key sleeve 274 carries a plurality of circumferentially arranged spring keys 276 mounted in respective radial slots 278. When in the illustrated initial configuration the spring keys 276 are engaged with an axial step 280 formed between different diameter sections of the mandrel 126, such that axial movement of the mandrel 126 in the first direction 22 will have the effect of compressing and energising the spring stack 270 against the spring face 272. When in the illustrated configuration the spring keys 276 are radially constrained by an inner surface of the housing 102. The inner surface of the housing 102 also includes an axial step 282 providing a transition to a larger inner diameter of the housing 102.

The force mechanism 198 may be used in any other application or apparatus, and is not exclusively for use in the example valve apparatus 100 currently disclosed. As such, an aspect of the present disclosure relates to a force mechanism.

Figure 2H illustrates a further region of the valve apparatus 100 in which the mandrel 126 includes optional features which permit engagement with external tools to facilitate manual manipulation of the mandrel 126 and thus operation of the valve apparatus. In this respect the mandrel 126 may include a first shifting profile 290 which permits engagement with a shifting tool (not shown) to shift the mandrel 126 in the first direction 22. The mandrel 126 may include a second shifting profile 292 which permits engagement with a shifting tool (not shown) to shift the mandrel 126 in the second direction. The valve apparatus 100 may also include a collet assembly 294 which may provide station keeping of the mandrel 126 relative to the housing 102 when in respective end travel positions.

Figure 2I illustrates an upper terminating end of the valve apparatus 100 which includes an upper connector 301 for facilitating connection of the valve apparatus 100 to other equipment, such as a tubing string, other tools such as a packer assembly etc. The region of the valve apparatus 100 illustrated in Figure 2I illustrates the terminating upper end 130 of the mandrel 126.

The valve apparatus 100 includes an optional circulating sub 300 which includes a plurality of circulating ports 302 extending radially through the housing 102, and a spring biased circulating sleeve 304 which is axially moveable within the housing 302 to selectively open and close the circulating ports 302. The circulating sub 300 includes a differential sealing arrangement which provides sealing against different diameter portions of the housing 102. More specifically, the differential sealing arrangement includes a major seal stack 306 and a minor seal stack 308. This differential sealing arrangement permits the circulating sleeve 304 to be moved in a preferred direction in accordance with the direction of a pressure differential between the annulus 116 and the flow path 104.

The circulating sub 300 also comprises a permanent seal 320 which may be used to permanently seal the circulating ports 302 if/when required. That is, the circulating sleeve 304 may be moved in a direction to cause the circulating ports 302 to be straddled by the permanent seal 320, thus removing any ability for the circulating sleeve 304 to be shifted by applied differential pressure (i.e., the effect of the differential sealing arrangement is neutralised).

In the illustrated initial configuration the circulating sleeve 304 is in a closed position (i.e., the ports 302 are closed) and locked to the housing 102 via a plurality of locking keys 310 engaged in a locking recess 312 and radially held in place by a lock sleeve 314. As will be described in more detail below, when the mandrel 126 is moved in the first direction 22 the lock sleeve 314 will be shifted to allow the locking keys 310 to become unsupported, unlocking the circulating sleeve 304 and allowing this to move in accordance with any pressure differential applied between the annulus 116 and flow path 104.

Operation of the valve apparatus 100, starting from its initial RIH configuration of Figures 2A to 2I, will now be described in detail below. For each operational step only those regions of the valve apparatus 100 which are affected are illustrated in enlarged view. However, to aid understanding, for each step illustrated in Figures 3 to 15 a global view of the valve apparatus 100 is provided with drawing suffix “A” which illustrates those regions of focus. For example, Figure 3A provides a global view of the valve apparatus 100, and illustrates region 3B which is shown in enlarged view in Figure 3B, reference to which is now made.

When the first actuator mechanism 108 (Figure 2B) is triggered, annulus pressure will be supplied via delivery conduit 112 to the first actuator 120, such that the piston assembly 144 is now exposed to any pressure differential between the annulus 116 and flow path 104. When the annulus pressure exceeds the tubing pressure by a sufficient magnitude the shear ring 176 of the first actuator 120 is sheared, causing the piston assembly 144 to be driven in the first direction 22 with the ratchet module 156 remaining stationary by engagement between the lower ratchet box 158 and inner sleeve 164. As illustrated, the ratchet pin 170 of the piston assembly 144 begins to retract from the upper ratchet box 166 of the ratchet module 156.

The piston assembly 144 moves into engagement with the lower end 128 of the mandrel 126, and thus applies a drive force in the first direction, initiating movement of the mandrel 126 in the same direction. As illustrated in Figure 4B, movement of the mandrel 126 causes the primary locking system 192 to become unlocked by virtue of the locking keys 246 becoming aligned with the unlocking region 252 of the mandrel 126. Thus, when in this configuration the second actuator 190 is released from the housing 102 and now effectively sensitive to applied pressure differentials.

At the same time, as illustrated in Figure 4C, the pressure relief arrangement 74 becomes closed by the mandrel 126, with the pressure relief valve sleeve 78 occluding the relief ports. Further, as illustrated in Figure 4D, the force mechanism 198 is energised by movement of the mandrel 126. That is, the spring stack 270 is compressed by the spring key sleeve 274 which is driven by the mandrel 126, until the keys 276 become aligned with the axial step 282 on the inner surface of the housing 102, allowing the mandrel 126 to continue movement in the first direction 22 and the spring compression to be locked against the housing 102.

Final movement of the mandrel 126 in the second direction causes the circulating sub 300 to become unlocked, as illustrated in Figure 5B. That is, the mandrel 126 shifts the lock sleeve 314 thus removing the support to the locking keys 310, freeing the circulating sleeve 304 from the housing 102. This final movement of the mandrel 126 also causes the valve member 124 to be rotated to its closed position, as illustrated in Figure 5C, thus closing the flow path 104.

Following this, as illustrated in Figure 6B, fluid is circulated down the annulus 116, with elevated annulus pressure acting over the major and minor seal stacks 306, 308 of the differential sealing arrangement causing the circulating sleeve 304 to be moved to open the circulating ports 302 and permit reverse circulation, represented by arrows 322.

When the circulating operation is completed pressure may then be elevated within the flow path 104, against the closed valve member 124, which causes the circulating sleeve 304 to close. Further, the dominating tubing pressure will cause the piston assembly 144 of the first actuator 120 to be returned, as illustrated in Figure 7B. As further illustrated in Figure 7C, which is an enlarged view of region 7C in Figure 7B, the piston assembly 144 drives the ratchet module 156 in the second direction, applying a force on the plug plunger 180 and shearing the shear assembly 182, with the plug 180 being pressed into the plug seat 178. This therefore closes the annulus pressure deliver bore 177, thus sealing communication with the annulus.

Further, the ratchet pin 170 of the piston assembly 144 is received into the ratchet box 166 of the ratchet module. As illustrated in Figure 7C, the ratchet pin 170 axially displaces the spacer ring 175, allowing the ratchet profile 172 of the pin 170 to engage the ratchet profile 168 of the box 166 and prevent separation of the piston assembly 144 and the ratchet module 156. The existing connection between the ratchet profile 160 on the lower ratchet box 158 and the ratchet profile 162 on the inner sleeve 164 prevents movement of the first actuator in the first direction 22. Thus, the first actuator 120 may now be considered to be redundant.

Further increasing the tubing pressure may then cause the circulating sub 300 to become locked closed, as illustrated in Figure 8B. In this respect the circulating sleeve 304 is caused to move in the second direction 26 by the dominating tubing pressure and straddling the permanent seal 320 across the circulating ports 320. An optional ratchet assembly 330 may be provided to further secure the circulating sleeve 304 from opening.

At this stage tubing pressure may be used for any desired operation, such as pressure testing, setting tools, such as packers, and the like. Following such operations it may be desirable to re-open the valve member 124, and the sequence for achieving this will now be described.

The initial stage requires the secondary locking system 194 to be unlocked, which will be described with reference to Figure 9B. Tubing pressure causes the second actuator 190 to apply a force on the locked hydraulic fluid 264, which is transmitted to the valve rod 264 of the second actuator mechanism. When tubing pressure is above a threshold, a shear mechanism holding the valve rod against movement is sheared-out, causing the valve rod to be moved, or primed, while remaining in a closed position. Bleeding tubing pressure then permits the valve rod to move in a reverse direction, under the action of annulus pressure via annulus port 260 and a return spring, to open a communication patch between the annulus port 260 and internal port 262.

Following this, the tubing pressure may be again elevated, above annulus pressure to provide a tubing/annulus pressure differential, which will cause the second actuator 190 to be driven in the second direction 26, displacing the hydraulic fluid 264 through the second actuator mechanism 196 and into the annulus 216. In Figure 9B the drive module 220 of the second actuator 190 has not yet engaged the mandrel 26, which has thus not yet been moved. Further, at the stage illustrated the shear pins 242 have travelled along the respective tracks 244 but not by a sufficient amount to cause these to shear.

Further movement of the second actuator 190 is illustrated in Figure 10B, in which the drive module 220 of the second actuator 190 is brought into engagement with the mandrel 126. Specifically, the drive interface 234 of each drive key 226 is engaged with the driven interface 236 on the mandrel 126. Further movement of the second actuator 190 thus drives the mandrel 126 in the second direction, until the shear pins 242 engage the ends of the tracks 244, as illustrated in Figure 11 B. In this respect, the shear pins 242 and tracks 244 may define a tertiary locking system acting on the second actuator 190. With sufficient force applied via the tubing annulus pressure differential, the shear rating of the shear pins 242 will be exceeded, permitting further movement of the second actuator 190 and the mandrel 126 in the second direction 22.

Further movement of the mandrel 126 triggers the force mechanism 198, as illustrated in Figure 12B, by aligning axial step 280 on the mandrel 126 with the spring keys 276, allowing said keys to be released form the housing 102 and the spring force to be directed on the mandrel 126 in the second direction 26.

Further movement of the mandrel 126 then causes the pressure relief arrangement 74 to be opened, as illustrated in Figure 13B, with the pressure relief valve sleeve 78 being shifted in the second direction 26 to open the relief ports 76, thus allowing pressure to equalise across the still closed valve member 124. Continued movement of the mandrel 126 will then cause the valve member 124 to be rotated to its open position, as illustrated in Figure 14B. When in this configuration the second actuator 190 has fully stroked, as illustrated in Figure 14C, such that the sealing nose 218 seals an annular communication 332 and thus isolating the second actuator 190 from the annulus 116. Further, in this final position the ratchet ring 238 (Figure 2G) is engaged with ratchet retainer sleeve 240 (also Figure 2G), thus preventing return movement of the second actuator 190. As such, in this configuration the second actuator 190 may be considered redundant.

Thus, once the valve apparatus has gone through a cycle of closing and opening the first and second actuators 120, 190 are both configured in a redundant state, and thus not capable of performing further actuation events. In this respect any requirement to further operate the valve apparatus may be achieved by manual intervention. For example, the sequence to manually re-close the valve member 124 will be described with reference to Figures 15B to 15F. Referring initially to Figures 15B, a shifting tool (not shown) is engaged with the first shifting profile 290 of the mandrel 126 to apply a force on the mandrel in the first direction 22. This force is resisted by engagement between the mandrel 126 and the drive keys 226 provided on the second actuator 190, as illustrated in Figure 15C. The tapered geometry of the drive and driven interfaces 234, 236 between the mandrel 126 and drive keys 226 causes the axial force applied by the shifting tool to be translated to a radial force acting on the shear screws 232 which fix the keys 226 to the key sub 230. When the shear rating of the shear screws 232 is reached these will shear-out, allowing the keys 226 to be released, thus allowing the mandrel to be shifted in the first direction 22, as illustrated in Figures 15D and 15E. This movement of the mandrel 126 causes the pressure relief arrangement 74 and the valve member 124 to be closed, as illustrated in Figure 15F.

Should the valve member 124 need to be opened again, a shifting tool may be deployed and engage second shifting profile 292 (Figure 2H), to drive the mandrel in the second direction.

It should be noted that many of the features presented above in relation to the valve apparatus 100 may be provided in one or more alternative forms, and indeed may be entirely optional. For example, the first actuator mechanism may be provided in a different format, while retaining the functionality to deliver annulus pressure to the first actuator. However, in further examples the first actuator mechanism may not be provided. Further, any alternative type of first actuator may be provided, for example other than the example hydraulic actuator described above. In some examples, the first actuator may not form part of the valve apparatus.

The primary locking system may be provided in any other format which permits unlocking to be achieved by movement of the mandrel.

The pressure relief arrangement may not be required. Also, the second actuator mechanism may be provided in any form suitable to provide a releasable locking function on the second actuator. For example, the second actuator mechanism may include a burst disc arrangement, a mechanical lock or latch, and/or the like. In some examples the second actuator mechanism may be omitted.

The second actuator may be provided in a different format, for example other than the example hydraulic actuator described above.

The force mechanism might not be required in some applications. Further, the circulating sub is optional.

It should also be noted that many features described in connection with the disclosed example valve apparatus may be used independently in any other application or apparatus.

Claims

54 CLAIMS

1. A downhole valve apparatus, comprising: a housing defining a flow path; a valve member mounted within the flow path and being operable between first and second positions to vary flow along the flow path; a mandrel moveable in reverse first and second directions to operate the valve member to move between its first and second positions, wherein the mandrel is moveable in the first direction by a first actuator to operate the valve member from its first position towards its second position; a second actuator operable by a trigger pressure differential between the flow path and a region external to the flow path to move the mandrel in the second direction to operate the valve member from its second position to its first position; and a primary locking system operable on the second actuator and configurable between a locked configuration in which the second actuator is in a non-active state and an unlocked configuration in which the second actuator is in an active state, wherein the primary locking system is configurable between its locked and unlocked configurations by movement of the mandrel in the first direction.

2. The downhole valve apparatus according to claim 1 , wherein the first position of the valve member comprises an open position and the second position of the valve member comprises a closed position, such that an initial movement of the valve member provided by the first actuator provides closure of the valve member, and subsequent movement of the valve member by the second actuator provides opening of the valve member.

3. The downhole valve apparatus according to claim 1 or 2, wherein the primary locking system provides releasable locking of the second actuator relative to the housing.

4. The downhole valve apparatus according to any preceding claim, wherein the primary locking system comprises a key mechanism comprising a locking key configured to be supported by the mandrel in locking engagement with the second actuator and the housing, wherein movement of the mandrel in the first direction 55 causes the locking key to become unsupported and disengageable from at least one of the second actuator and the housing.

5. The downhole valve apparatus according to claim 4, wherein one of the second actuator and the housing defines a radial key pocket for receiving the locking key, and the other of the second actuator and housing defines a locking profile (e.g., recess, channel, etc.), such that radial movement of the locking key within the key pocket causes selective engagement and disengagement of the locking key with the locking profile, optionally wherein the housing defines the radial key pocket and the second actuator defines the locking profile.

6. The downhole valve apparatus according to any preceding claim, wherein the second actuator comprises an actuator piston, a first axial side of the actuator piston being configured or configurable for pressure communication with the flow path, and an opposite second axial side of the actuator piston being configured or configurable for pressure communication with the external region.

7. The downhole valve apparatus according to any preceding claim, wherein the second actuator is at least partially mounted and axially moveable within an actuator cavity defined within the apparatus.

8. The downhole valve apparatus according to claim 7, wherein the apparatus comprises a flow path port for providing pressure communication between the flow path and the actuator cavity, and an external region port for providing pressure communication between the external region and the actuator cavity.

9. The downhole valve apparatus according to claim 8, wherein the second actuator is configured to seal the external region port after an operation to move the mandrel in the second direction to operate the valve member from its second position to its first position.

10. The downhole valve apparatus according to any one of claims 7 to 9, wherein the actuator cavity is defined between inner and outer wall structures of the housing, said inner wall structure being positioned radially between the mandrel and the second actuator. 56

11. The downhole valve apparatus according to claim 10, wherein the inner wall structure defines a radial key pocket configured to accommodate a locking key for use in engaging and disengaging the second actuator in accordance with the position/movement of the mandrel.

12. The downhole valve apparatus according to any preceding claim, comprising a drive arrangement for permitting the second actuator, when in its active state, to drivingly engage the mandrel in the second direction.

13. The downhole valve apparatus according to claim 12, wherein the drive arrangement comprises a drive interface provided on the second actuator and a driven interface provided on the mandrel.

14. The downhole valve apparatus according to claim 13, wherein the drive and driven interfaces are initially separated such that an initial separation gap is provided therebetween to permit the mandrel to be moved in the first direction to operate the valve member from its first position towards its second position.

15. The downhole valve apparatus according to claim 14, wherein movement of the mandrel in the first direction reduces the separation gap between the drive and driven interfaces such that when the mandrel is fully stroked in the first direction a residual separation gap remains between the drive and driven interfaces, wherein said residual separation gap is closed during movement of the second actuator in the second direction to bring the drive and driven interfaces into engagement.

16. The downhole valve apparatus according to claim 15, wherein the residual separation gap permits a degree of lost motion between the second actuator and the mandrel in the second direction.

17. The downhole valve apparatus according to any one of claims 12 to 16, wherein the drive arrangement is configurable into a deactivated state, in which force transmission between the second actuator and the mandrel is prevented. 57

18. The downhole valve apparatus according to claim 17, wherein at least one of the drive and driven interfaces is releasably mounted on the respective second actuator and mandrel to permit the drive arrangement to be deactivated.

19. The downhole valve apparatus according to claim 18, wherein the drive interface comprises a drive key mounted on the second actuator via a releasable connection.

20. The downhole valve apparatus according to claim 19, wherein the drive key is radially supported and prevented from being released from the second actuator until the second actuator is in a defined position within the valve apparatus corresponding to the mandrel being driven a predefined distance in the second direction to ensure the valve member is again in its first position.

21. The downhole valve apparatus according to any preceding claim, comprising a secondary locking system configurable from a locked configuration in which movement of the second actuator is constrained by the secondary locking system, and an unlocked configuration in which movement of the second actuator is unconstrained by the secondary locking system.

22. The downhole valve apparatus according to claim 21 , wherein the secondary locking system is configurable from its locked to unlocked configurations after the primary locking system is configured in its unlocked configuration, such that the primary and secondary locking systems are configured to be operated in sequence.

23. The downhole valve apparatus according to claim 21 or 22, wherein the secondary locking system is reconfigured from its locked configuration to its unlocked configuration by operation of the second actuator.

24. The downhole valve apparatus according to claim 23, wherein the second actuator is configured, once in its active state, to apply a force or series of forces on the secondary locking system to reconfigure said secondary locking system into its unlocked configuration.

25. The downhole valve apparatus according to any one of claims 21 to 24, wherein the secondary locking system comprises: a fluid volume in communication with the second actuator such that movement of the second actuator acts on the fluid volume; and a fluid release mechanism configured to release or vent the fluid volume and configure the secondary locking system into its unlocked configuration.

26. The downhole valve apparatus according to claim 25, wherein the fluid release mechanism is configured to release the fluid volume in response to a predetermined release action comprising varying the pressure of the fluid volume by operation of the second actuator to impart a force on the fluid volume.

27. The downhole valve apparatus according to any preceding claim, comprising a valve operator forming part of the mandrel, said valve operator for engaging the valve member and converting movement of the mandrel to movement of the valve member.

28. The downhole valve apparatus according to any preceding claim, comprising a pressure relief arrangement operable between closed and open configurations to selectively permit pressure communication of the flow path on opposing sides of the valve member when said valve member is in a closed configuration.

29. The downhole valve apparatus according to claim 28, wherein the pressure relief arrangement may be operated by movement of the mandrel such that movement of the mandrel provides sequential operation of the pressure relief arrangement and the valve member.

30. The downhole valve apparatus according to any preceding claim, comprising a force mechanism for providing a bias force on the mandrel in the second direction.

31. The downhole valve apparatus according to claim 30, wherein the force mechanism defines an initial configuration and an energised configuration, and wherein the force mechanism is reconfigured from its initial configuration to its energised configuration by movement of the mandrel in the first direction.

32. The downhole valve apparatus according to any preceding claim, wherein the first actuator is operable in response to a pressure differential applied between the flow path and the external region.

33. A method for operating a downhole valve apparatus, the method comprising: providing a valve member in a first position; moving a mandrel in a first direction using a first actuator to operate the valve member to move from its first position towards its second position, wherein movement of the mandrel in the first direction unlocks a second actuator to reconfigure the second actuator between an non-active and an active state; and operating the second actuator by a trigger pressure differential between a flow path within the valve apparatus and a region external to the flow path to move the mandrel in the second direction to operate the valve member from its second position to its first position.

34. A downhole valve apparatus, comprising: a housing defining a flow path; a valve member mounted within the flow path and being operable between open and closed positions to vary flow along the flow path; a mandrel moveable in reverse first and second directions to operate the valve member to move between its open and closed positions, wherein the mandrel is moveable in the first direction by a first actuator to operate the valve member from its open position towards its closed position; a second actuator operable by a trigger pressure differential between the flow path and a region external to the flow path to move the mandrel in the second direction to operate the valve member from its closed position to its open position; a pressure relief arrangement operable by the mandrel when moved in the second direction such that the pressure relief arrangement is opened before the valve member to provide pressure relief across the valve member prior to being opened; and a force mechanism configured to provide a bias force on the mandrel in the second direction.