GB2562992A

GB2562992A - Closure apparatus

Info

Publication number: GB2562992A
Application number: GB1703985.0A
Authority: GB
Inventors: David Cowie Gavin; David Sangster John
Original assignee: Interventek Subsea Engineering Ltd
Current assignee: Interventek Subsea Engineering Ltd
Priority date: 2017-03-13
Filing date: 2017-03-13
Publication date: 2018-12-05
Anticipated expiration: 2037-03-13
Also published as: GB201703985D0; GB2562992B

Abstract

A closure apparatus for closing a bore, such as in a wellbore or wellhead, comprising a housing 12 having a bore, a closure element 12, and an actuator 32 coupled to the closure element for operating the closure element to move between its open and closed positions. An interface mechanism 42 between the closure element and the housing controls the closure element to move from its open position to its closed position in a first rotational movement and second linear movement sequentially. The closure apparatus may function as a blowout preventer and may be arranged to seal against or cut a tubular within the bore. The interface mechanism may comprise a track and follower arrangement.

Description

CLOSURE APPARATUS

FIELD

The present disclosure relates to a closure apparatus for providing a closing function within a bore, such as a bore associated with a well.

BACKGROUND

In the oil and gas industry many operations require some form of closure within a bore, such as within a wellbore, within equipment associated with a wellbore or the like. In some examples such closure may be provided to achieve fluid isolation or sealing within the bore, such as might be the case in a Blow Out Preventer (BOP), Subsea Test Tree (SSTT), fluid valves and the like. Fluid isolation might be required in an open bore, i.e., without any physical restriction present within the bore. Alternatively, fluid isolation might be required in an annulus surrounding a physical restriction, such as tubing, wireline, tooling or the like which extends through the bore.

In some other examples a closure event may be required to cut through an object extending through the bore, with or without subsequent bore sealing. Further, closure may be required to engage or grip an object extending through the bore, without necessarily providing a sealing function, for example to support the object within the bore.

In many known systems one or more elements are provided which are moveable relative to an associated bore between open and closed positions. The elements, which may be provided in the form of sealing rams, pipe rams, shearing rams, gripping slips and/or the like, are typically moveable in a linear manner, laterally relative to the bore, via linear piston actuators. In order to ensure the elements do not restrict the bore when in an open position it is often necessary for the actuators to provide a relatively long actuation stroke, which may create issues in terms of space.

Some proposed systems might alternatively utilise rotary motion of the elements. However, in some cases suitable operational forces might not be achievable, for example to the extent that might be required to cut through objects such as tubing. Furthermore, a rotating motion might compromise appropriate functioning of the elements, for example in terms of sealing, cutting, gripping or the like.

SUMMARY

An aspect of the present disclosure relates to a closure apparatus for providing a closing function within a bore. The closing function may include sealing, gripping, cutting, guiding, centralising and/or the like.

The closure apparatus may comprise a housing which defines the bore, wherein the bore extends axially through the housing.

The closure apparatus may comprise a closure element moveable from an open position in which the closure element is retracted from the bore and a closed position in which the closure element is extended into the bore.

The closure apparatus may comprise an actuator coupled to the closure element for operating the closure element to move between its open and closed positions. The actuator may be operable along a stroke path.

The closure apparatus may comprise an interface mechanism interposed between the closure element and the housing for controlling the closure element to move from its open position to its closed position in sequential first and second movement phases during operation of the actuator. The first movement phase may comprise a rotating motion of the closure element from its open position to an intermediate position. The second movement phase may comprise a linear movement without rotation from the intermediate position to its closed position.

An aspect of the present disclosure relates to a closure apparatus for providing a closing function within a bore, comprising:

a housing defining a bore extending axially therethrough; a closure element moveable from an open position in which the closure element is retracted from the bore and a closed position in which the closure element is extended into the bore;

an actuator operable along a stroke path and coupled to the closure element for operating the closure element to move between its open and closed positions; and an interface mechanism interposed between the closure element and the housing for controlling the closure element to move from its open position to its closed position in sequential first and second movement phases during operation of the actuator, wherein the first movement phase comprises a rotating motion of the closure element from its open position to an intermediate position, and the second movement phase comprises a linear movement without rotation from the intermediate position to its closed position.

Thus, during operation of the closure apparatus, the closure element may be moved relative (i.e., into) to the bore from its open position to its closed position through the sequential combination of the first and second movement phases. The rotational aspect of the first movement phase may assist to provide a greater degree of extension of the closure element into the bore for a reduced stroke of the actuator. The linear aspect of the second movement phase may permit improved final operation of the closure element. For example, final engagement or positioning of the closure element is achieved by the linear movement, without rotation, which may provide advantages in terms of maximising available actuation force to perform a desired function when at or reaching the closed position. As a further example, the final linear movement, without rotation, may allow better engagement of the closure element with one or more other features, such as other closure elements, parts of the housing, tubing, wireline or the like which may be positioned within the bore.

The second movement phase of the closure element may perform a desired function within the bore. For example, the second movement phase may function to energise a seal, cut an object, grip an object, establishing interference with an object, and/or the like. The linear movement, without rotation, during the second movement phase may improve the effectiveness of the desired function within the bore.

The actuator may comprise a linear actuator. The actuator may be arranged to stroke along a linear stroke path. The orientation of the linear stroke path may be fixed during operation of the actuator.

The actuator may comprise a fluid operated actuator. The actuator may comprise a piston, ram or the like.

The actuator may be provided within the housing. Alternatively, the actuator may be provided at least partially externally of the housing, for example secured to an outer surface of the housing.

The interface mechanism may be arranged such that the linear operation applied by the actuator is converted to a rotational movement of the closure element during the first movement phase. Further, the interface mechanism may be arranged such that the linear operation applied by the actuator provides only linear movement of the closure element during the second movement phase.

The linear movement of the closure element during the second movement phase may be provided in a lateral direction relative to the bore of the housing. The linear movement of the closure element may be provided in a perpendicular direction relative to the bore. In some other examples the closure element may be moved obliquely relative to the bore. The linear movement of the closure element may be provided along a path of movement which is aligned or parallel with the stroke path of the actuator.

The interface mechanism may permit the first and second movement phases to be achieved during a single operation of the actuator. For example, the first and second movement phases may be achieved during a single stroke of the actuator, such as a single stroke in a single direction.

The interface mechanism may provide a transition movement phase between the first and second movement phases. During the transition movement phase the closure element may be operated in a composite movement of rotation and linear movement into the bore, wherein the rotational movement becomes reduced to zero to allow only linear movement of the closure element during the second movement phase.

In an alternative example any transition between the first and second movement phase may be substantially instantaneous, abrupt or step-wise.

The closure element may be moveable from its closed position to its open position. This may be achieved by reverse operation of the actuator. The interface mechanism may control the closure element to be sequentially moved in the reverse second and first movement phases during reverse operation of the actuator.

The actuator may be coupled to the closure element. The actuator may be coupled to the closure element via a pivot connection. The pivot connection may permit the closure element to be rotated during the first movement phase. In this respect, the closure element may be rotated during the first movement phase about a rotation axis defined by or at the pivot connection between the actuator and the closure element. The pivot connection may be provided by a pinned connection or the like.

The rotation axis may extend laterally relative to the axis of the bore. The rotation axis and the axis of the bore may not intersect. For example, the rotation axis may be considered tangential to the bore.

The pivot connection between the actuator and the closure element may provide a constrained linear connection between the actuator and the closure element. For example, the connection between the actuator and the closure element may prevent relative linear motion therebetween, thus only permitting relative rotational movement therebetween.

The pivot connection between the actuator and the closure element may move in space during operation of the actuator. For example, the pivot connection may be moved linearly in space during operation of the actuator. The path of movement of the pivot connection may be aligned with a stroke path of the actuator.

The provision of the interface mechanism separately from any connection between the actuator and the closure element may simplify the structure of the closure apparatus. For example, the connection between the actuator and the closure element may be simplified, which may facilitate improved connection, improved coupling and transmission of force between the actuator and the closure element and the like.

The closure element may define a point of interface with or relative to the interface mechanism. The interface mechanism may control the movement of the point of interface along a predetermined locus path to facilitate the desired movement of the closure element during operation of the actuator. The predetermined locus path may comprise first and second locus components, wherein the interface point of the closure element moves along the first locus component during the first movement phase, and along the second locus component during the second movement phase. In one example the first and second locus components may be linear (i.e., arranged along a linear, non-curved path). The first and second locus components may be arranged substantially perpendicular to each other, although in other examples an oblique orientation may be provided. In one example the first locus component may be arranged substantially parallel with the axial direction of the bore of the housing, and the second locus component may be arranged laterally to the axial direction of the bore of the housing.

In one example the first locus component may arranged laterally to the stroke path of the actuator. In one example the second locus component may be aligned with, for example parallel with, the stroke path of the actuator.

The predetermined locus path may comprise a transition locus component between the first and second locus components. In one example the transition locus component may be curved.

The point of interface may be laterally, for example radially, disposed from the connection between the closure element and the actuator. This lateral/radial separation of the point of interface, in combination with the form of the interface mechanism, may permit a turning moment to be generated which allows the closure element to be rotated during the first movement phase.

The interface mechanism may comprise one or more elements formed directly in one or both of the housing and the closure element. The interface mechanism may comprise one or more elements formed separately from one or both of the housing and the closure element. Any separately formed elements may be coupled to the housing and/or the closure element.

The interface mechanism may comprise a track and follower arrangement interposed between the housing and closure element. The form and geometry of the track and follower arrangement may control the movement of the closure element in the first and second movement phases during operation of the actuator. The track and follower arrangement may comprise interfacing track and follower features.

In one example the interface mechanism may include a continuous track feature at a common location, wherein this continuous track provides both the first and second movement phases. However, in other examples the interface mechanism may be established by individual track features located at different locations within the apparatus. For example, a track feature may be arranged to provide the first movement phase, whereas a separate track feature at a separate location may be arranged to provide the second movement phase.

The track feature may be associated with one of the housing and the closure element, and the follower feature may be associated with the other of the housing and the closure element. In one example, the track feature may be associated with the housing and the follower feature may be associated with the closure element.

The track feature may comprise a track edge arranged to be engaged by the follower, such that the follower may move relative to or along the track edge. The track feature may comprise a slot or groove, such as formed by one or more recesses in a surface or surfaces, wherein at least one side wall of the track defines the track edge. Alternatively, the track feature may comprise a step, wherein a wall of the step defines the track edge. The step may be provided by a lip, rib, shoulder or the like.

The track and follower features may be arranged for relative sliding engagement. The track and follower features may be arranged for relative rolling engagement.

The follower may comprise a pin element. The follower may comprise a bearing element, such as a roller bearing element.

The track feature may comprise at least first and second track components arranged in different directions, wherein the first track component defines the first movement phase of the closure element, and the second track component defines the second movement phase of the closure element.

One or both of the first and second track components may be linear. One or both of the first and second track components may be curved.

The first track component may extend in a direction which is lateral, for example oblique or perpendicular, to the stroke path of the actuator. Such an arrangement may permit a turning moment to be generated during operation of the actuator.

The second track component may extend in a direction which is aligned, for example parallel, with the stroke path of the actuator. Such an arrangement may control the closure element to move linearly without further rotation during the second movement phase.

The track feature may comprise a transition component between the first and second track components. The transition component may be curved.

The closure apparatus may comprise a retaining arrangement for retaining the closure element in its closed position. The retaining arrangement may comprise the actuator. The retaining arrangement may be provided separately from the actuator. The retaining arrangement may be operated upon the closure element reaching its closed position.

In one example the retaining arrangement may comprise a lock mechanism which locks the actuator.

The retaining arrangement may comprise a lock mechanism which directly locks the closure element. The retaining arrangement may comprise a retaining ring or the like.

Rotation of the closure element from its closed position during the first movement phase may cause a free portion (e.g., inner portion) of the closure element to move inward (i.e., into the bore) and also in the axial direction of the bore. For example, the bore may define first and second axial ends, wherein the closure element may rotate from its closed position in a direction towards one of the first and second ends. The closure element may be mounted within the housing in such a manner such that the rotation direction is preferred according to an end use. For example, any forces applied on the closure element when in a closed position, such as from fluid pressure, mechanical interference or the like, may establish a force bias on the closure element. The closure element may be mounted to ensure this force bias is in a preferred direction, such as to increase closing force, reduce closing force and the like.

The closure element may function to provide or contribute to sealing within the bore when the closure element is in its closed position. The linear movement of the closure element during the second movement phase may assist to improve sealing engagement of the closure element when approaching its closed position.

In one example the closure element may comprise a sealing arrangement, such as an elastomeric seal arrangement, a non-elastomeric sealing arrangement, synthetic seal arrangement such as a comprising PTFE or the like.

The closure apparatus may comprise a sealing seat which circumscribes the bore. The closure element may sealingly engage the sealing seat when the closure element is in its closed position.

The closure element may be arranged to provide or contribute to sealing within an open bore (i.e., within the bore without any restriction or object therein). In such an example the closure element may be arranged to engage with a portion of the housing, other components of the closure apparatus, such as a sealing seat, a second closure element and/or the like. In this example the closure element may define or be provided to function as a blind ram. In one example the closure element may cooperate with one or more other closure elements (which may or may not be configured similarly) to completely close and seal the bore.

The closure element may be arranged to provide or contribute to sealing within the bore with an object therein, such as tubing, wireline, tooling or the like. In this example the closure element may close and seal a region (for example an annulus region) around the object. The closure element may seal against the object. The closure element may define a profile which corresponds or accommodates at least a portion of an outer surface of an object located within the bore. In this example the closure element may define or be provided to function as a pipe ram. In one example the closure element may cooperate with one or more other closure elements (which may or may not be configured similarly) to completely close and seal the space around the object.

The closure element may be arranged to provide sealing within the bore against a pressure differential in opposite directions along the bore (e.g., bi-directional sealing).

The closure element may provide preferential sealing within the bore against a pressure differential acting in one direction along the bore. For example, a pressure differential acting in a first direction along the bore may facilitate improved sealing, for example by establishing a further force on the closure element acting in a closure direction. Conversely, a pressure differential acting in an opposite second direction along the bore may more readily disrupt sealing, for example by establishing a force which acts on the closure element in its opening direction. Such an arrangement may facilitate desired functioning or application of the closure apparatus. For example, in some example uses a pump-through capability past the closed closure element in one direction might be desirable. Further, the ability to provide a preferential sealing direction may permit uses of the closure apparatus in operations in which selective opening and closing of the closure element may be desirable in accordance with control of flow and/or pressure.

Further, in some examples the closure element may be displaced by mechanical interference from an object moving through the bore in one direction, for example by connectors arranged along a tubing string, such as a drill string, during deploying into a wellbore.

The closure element may provide a support function within the bore when the closure element is in its closed position. For example, the closure element may be arranged to anchor or grip an object extending through the bore. The object may comprise tubing, tooling and/or the like. In this example the closure element may define or be provided to function as an anchor slip. Such anchoring or gripping may secure the object, for example suspend the object, within the bore. The linear movement of the closure element during the second movement phase may assist to improve engagement with the object.

The closure element may establish a no-go profile within the bore when the closure element is in its closed position. The no-go profile may provide a load point to be engaged by an object, such as an object having an annular collar or the like.

In some examples when the closure element provides a gripping or support function, fluid may be permitted to bypass the closure element.

In one example the closure element may cooperate with one or more other closure elements (which may or may not be configured similarly) to provide multiple points of support for an object.

The closure element may provide a position control function within the bore when the closure element is in its closed position. For example, the closure element may function to position an object into a desired position relative to the bore. In one example the closure element may assist to centralise an object within the bore.

The closure element may provide a cutting function within the bore. For example, the closure element be arranged to cut an object, such as wireline, tubing, tooling and/or the like, located within the bore. In this example the closure element may define or be provided to function as a shear ram. The cutting operation may be performed during the second movement phase of the closure element. This may maximise a cutting force applied by the actuator, assisting to improve the cutting effect of the closure element.

The closure element may comprise a cutting element, such as a shear cutting blade, for cutting an object. In one example the closure element may cooperate with one or more other closure elements (which may or may not be configured similarly) to cut an object within a bore. For example, multiple closure elements may be provided with cooperating blades.

The closure element may provide a cutting and subsequent sealing function within the bore. For example, after cutting through an object within the bore, the closure element may provide a sealing function within the bore.

The closure element may comprise a guide arrangement, for engaging and guiding an object into a desired position within the bore. This may allow the object to be appropriately aligned with the closure element for its desired function, such as gripping, sealing, cutting and/or the like. The guide arrangement may be configured to centralise the object relative to the bore. The guide arrangement may comprise one or more tapered features or the like.

The closure element may provide multiple functions. For example, the closure element may provide at least two of sealing, gripping, guiding, cutting or the like.

The housing may define a pocket to accommodate the closure element when in its open position.

The closure element may be entirely retracted form the bore when in its open position. That is, the closure element may sit outside the minimum diameter of the bore. In other examples the closure element may remain partially extended into the bore when in its open position

The closure element may be provided as a unitary component. Alternatively, the closure element may comprise multiple components which are assembled together.

The closure apparatus may comprise multiple closure elements. At least two closure elements may be substantially similar, at least in relation to their intended function. For example, at least two closure elements may be arranged to provide a sealing function, provide a cutting function, provide a support function and/or the like.

At least two closure elements may be different, at least in relation to their intended function. For example, a first closure element may be configured to provide a sealing function, and a second closure element may be configured to provide a griping function.

The actuator may function to operate multiple closure elements. Alternatively, the closure apparatus may comprise multiple actuators each associated with at least one closure element.

Multiple closure elements may be provided at the same axial location along the bore. Different closure elements at the same axial location may provide a common function. Different closure elements at the same axial location may provide different functions.

Multiple closure elements may be provided at different axial locations along the bore. Such an arrangement may facilitate the provision of one of more functions (for example the same or different functions) at different locations along the bore. For example, one or more closure elements provided at one axial location may provide a first function (e.g., gripping), and one or more closure elements provided at a different axial location may provide a second function (e.g., sealing).

The closure apparatus may be configured for use with a wellbore. For example, the closure apparatus may be configured for use within a wellbore. In this example the bore of the closure apparatus may define a portion of the wellbore. In some examples the closure apparatus may be arranged to be coupled to a wellbore, such that the bore of the housing is provided in fluid communication with the wellbore. The housing of the closure apparatus may comprise one or more connectors, such as flange connectors or the like.

The closure apparatus may define well control apparatus. In some examples the closure apparatus define or form part of a BOP, SSTT, wellhead assembly, production tree and/or the like.

The closure apparatus may be for use in-well, subsea, topside and/or the like.

An aspect of the present disclosure relates to a method for providing a closing function within a bore, comprising:

operating an actuator to move a closure element from an open position in which the closure element is retracted from the bore to a closed position in which the closure element is extended into the bore; and controlling the closure element via an interface mechanism to move from its open position to its closed position in sequential first and second movement phases during operation of the actuator, wherein the first movement phase comprises a rotating motion of the closure element from its open position to an intermediate position, and the second movement phase comprises a linear movement without rotation from the intermediate position to its closed position.

The method may be performed using a closure apparatus according to any other aspect.

Further aspects of the present disclosure relate to apparatus and methods for at least one of:

providing a sealing function within a bore; providing a cutting function within a bore; providing a support function within a bore; and providing a centralising function within a bore.

Such apparatus and methods may be performed using a closure apparatus according to any other aspect.

Features defined in relation to one aspect may be provided in combination with any other aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

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

Figure 1 is a cross-sectional isometric view of a closure apparatus, shown with closure elements positioned in an open configuration;

Figure 2 is an isometric view of a closure element of the apparatus of Figure 1;

Figure 3 is a diagrammatic representation of an interface mechanism of the apparatus of Figure 1;

Figure 4 illustrates the apparatus during initial stages of a first movement phase of the closure elements;

Figure 5 illustrates the apparatus during a later stage of the first movement phase of the closure elements;

Figure 6 illustrates the apparatus during the initiation of a subsequent second movement phase of the closure elements;

Figure 7 illustrates the apparatus with the closure elements in a closed position following completion of the second movement phase;

Figures 8 and 9 are isometric views of alternative forms of a closure element;

Figure 10 is an isometric view of a pair of closure elements which are configured to provide a cutting function;

Figure 11 diagrammatically illustrates the closure elements of Figure 10 in an open configuration;

Figure 12 diagrammatically illustrates the closure elements of Figure 10 at the end of a first movement phase;

Figure 13 diagrammatically illustrates the position of the closure elements shown in Figure 12 from above;

Figure 14 diagrammatically illustrates the closure elements of Figure 10 during the initiation of a second movement phase and initial cutting;

Figure 15 diagrammatically illustrates the closure elements of Figure 10 in a fully cut and closed position following completion of the second movement phase; and

Figure 16 is a cross-sectional view of an example closure apparatus which includes axially separates sets of closure elements.

DETAILED DESCRIPTION OF THE DRAWINGS

Figure 1 illustrates, in cross-section, a closure apparatus 10 which includes a housing 12 which defines a bore 14 extending axially therethrough. The closure apparatus 10 may be used in multiple applications where a closing function is required within a bore, and a number of examples of this will be presented below. For the purposes of the present exemplary disclosure the closure apparatus 10 is to be secured to a wellbore (for example at a wellhead), such that the bore 14 is in fluid communication with the wellbore, and to provide a sealing function against tubing (not shown in Figure 1) which extends through the bore 14.

The apparatus 10 includes a pair of closure elements 16 mounted on opposing sides of the housing 12 and bore 14 and which, according to their intended function, may be defined as pipe rams. In the present example the closure elements 16 are identical in form and function; a single closure element 16 removed from the apparatus 10 is illustrated in Figure 2, reference to which is additionally made.

The closure elements 16 are illustrated in Figure 1 in an open position, retracted from the bore 14. In this respect the housing 12 defines an opposing pair of recessed pockets 17 which allow the closure elements 16 to be retracted, such that the closure elements provide minimum restriction within the bore 14.

Each closure element 16 includes an upper face 18, inner face 20 and tubing recess

22. A sealing element 24, which may be elastomeric, extends within a groove 25 formed in the upper face 18, inner face 20 and tubing recess 22. As will be described in further detail below, the portion of the sealing element 24 on the upper face 18 is arranged to sealingly engage a seal surface 26 of a seat 28 mounted within the housing 12 around a periphery of the bore 14. The portion of the sealing element 24 on the inner face 20 is arranged to sealingly engage the corresponding sealing element 24 on the inner end face 20 of the opposing closure element 16. Further, the portion of the sealing element 24 provided in the tubing recess 22 is arranged to sealingly engage an outer surface of tubing. Thus, when the closure elements 16 are closed, which will be described in detail below, complete sealing within the bore 14 can be achieved.

The upper face 18 of each closure element 16 also includes a chamfered or tapered portion 30 which provides additional clearance from the bore 14 when the closure elements 16 are in their open position. The chamfered or tapered portion 30 may also or alternatively function as a kick-down feature, which in use in a closed position may be engaged by a separate object (such as a tubing connector or the like), to move the closure element towards an open position.

The apparatus 10 further comprises a pair of opposing linear piston actuators 32 mounted on the outer surface of the housing 12. Each actuator 32 includes a cylinder 34 and a piston 36 slidably mounted within the cylinder, and moveable in reverse directions along a linear stroke path 37 under the action of fluid pressure applied selectively on opposing sides of the piston 36. A piston rod 38 extends from each piston 36 and through a wall of the housing 12, wherein the end of each piston rod 38 is connected to a respective closure element 16 via a pivot connection 40. Thus, each closure element 16 is rotatable about a pivot axis at the pivot connection 40 with the respective piston rods 38. Further, the respective pivot connections 40 are moveable linearly along the stroke path 37 during operation of the associated piston actuators 32.

The apparatus 10 further includes an interface mechanism 42 interposed between each closure element 16 and the housing 12. As will be described in more detail below, each interface mechanism 42 assists to control the closure elements 16 to move from their open position to their closed position in sequential first and second movement phases during operation of the actuators 32. Specifically, the first movement phase comprises a rotating motion of the closure elements 16 about their respective pivot connections 40 from the open position to an intermediate position, and the second movement phase comprises a linear movement, without rotation, from the intermediate position to the closed position.

In the present example each interface mechanism 42 includes a track and follower arrangement, as diagrammatically illustrated in Figure 3. In this case a generally Lshaped track 44 is provided on the housing 12, and a pin 46 is provided with the associated closure element 16 and engaged with the track 44. During operation of the associated actuator 32 the pin 46 is guided along the track 44 along a predetermined locus path to provide the desired first and second movement phases of the closure element 16. The pin 46 is provided at a radial distance from the pivot axis defined by the pivot connection 40 between the associated actuator 32 and closure element 16.

The track 44 includes a track edge 47 which includes a first track component 48, a second track component 50 and a transition track component 52. In the present example the first track component 48 extends to be generally perpendicular relative to the stroke path 37 of the actuators 32, whereas the second track component 50 extends parallel with the stroke path 37. The transition track component 52 provides an appropriate radius of curvature between the first and second track components 48, 50.

In the present example the track 44 includes a further track edge 53 which runs parallel with track edge 47. The parallel track edges 47, 53 may be provided by edges of a slot. The further track edge 53 may cooperate with the pin 46 to provide movement control of the closure element 16 when operated in a reverse direction (i.e., in a direction from a closed position to an open position. However, in some cases only a single track edge 47 may be provided.

In the present example each closure element 16 may be associated with a single interface mechanism 42. However, in other examples each closure element 16 may be associated with a pair of interface mechanisms 42 on opposing sides of the respective closure elements 16.

Sequential stages of operation of the apparatus 10, from its initial fully open position of Figure 1 to a fully closed position will now be described with reference to Figures 4 to 7, which each illustrate the apparatus 10 in cross-section, with the interface mechanism 42 diagrammatically illustrated separately in each case for clarity. Further, a tubing string 54 (e.g., coiled tubing) is illustrated in Figures 4 to 7, extending though the bore

14.

During initial operation of the actuators 32, as illustrated in Figure 4, the respective pivot connections 40 at each closure element 16 begin to move linearly along the stroke path 37, inwardly relative to the bore 14. The pin 46 of each interface mechanism 42 is engaged against the first track component 48, which may be defined as a point of interface, thus permitting a turning moment to be established about the pivot connection 40, providing rotation of the closure element 16 in the first movement phase. During such rotation the pin 46, and thus the point of interface between the pin 46 and the track edge 47, moves along the first track component 48, in a downward direction relative to the orientation of Figure 4, until reaching the start of the transition track component 52. In this example, the first track component therefore defines a first locus component of the predetermined locus path.

Continued operation of the actuators 32, illustrated in Figure 5, will cause the pin 46 to be guided through the transition track component 52, with a composite of rotation and linear motion of the closure element 16 occurring.

Further operation of the actuators 32, illustrated in Figure 6, will cause the pin 46 to be guided into the second track component 50, ready to establish the second movement phase according to a second locus component of the predetermined locus path. Engagement of the pin 46 with the second track component may prevent further rotation of the associated closure element 16 during continued operation of the actuator 32. In the configuration of Figure 6 the closure elements 16 may be arranged in an intermediate position, and not yet in sealing engagement.

Final operation of the actuators 32, illustrated in Figure 7, will cause the pin 46 to move along the second track component 50 to a final position. In this respect, as the second track component 50 is parallel with the stroke path 37 of the actuator 32, no further turning moment will be generated, such that the closure elements 16 will move linearly, in a lateral direction relative to the bore 14 of the housing 12, without further rotation in the second movement phase. The closure elements 16 will thus be located in their final closed position, providing sealing engagement with each other, with the tubular 54 and with the seat 28, thus sealing an annulus area around the tubular 54. The ability to bring the closure elements 16 into their final closed position in a purely linear manner may assist to provide a more robust sealing engagement, for example by providing better alignment between the sealing members 24, providing more efficient use of the linear actuation force from the actuators 32 and the like.

During a reverse operation of the actuators 32, a reverse controlled movement of the closure elements 16 may be provided by engagement of the pin 46 with the further track 53 (Figure 3).

In the example provided above the interface mechanism includes a continuous track feature at a common location, wherein this continuous track provides both the first and second movement phases. However, in other examples the interface mechanism may be established by individual elements located at different locations within the apparatus 10. For example, a track or equivalent feature may be arranged to provide the first movement phase, whereas a separate track feature at a separate location may be arranged to provide the second movement phase.

In the example provided above the closure elements 16 are provided in the form of pipe rams, configured to engage around a tubular 54. However, in other examples the closure elements may be arranged to engage around more slender objects, such as wireline. In this case the closure elements may be modified to include a shallower or smaller recess in their inner faces.

In a further example the closure elements may be provided to function as blind rams to seal the associated bore in the closure apparatus without any object therein. A modified closure element 116 for use in such a blind ram function is shown in Figure 8, wherein the closure element 116 is similar in most respects to closure element 16 and as such like features share like reference numerals, incremented by 100. Thus closure element 116 includes an upper face 118 and inner face 120, without any recess (e.g., for tubing or wireline). A sealing element 124, which may be elastomeric, extends within a groove 125 formed in the upper face 118 and the inner face 120. When used in the closure apparatus of Figure 1, the portion of the sealing element 124 on the upper face 118 is arranged to sealingly engage the seal surface 26 of the seat 28 (see Figure 1), and the portion of the sealing element 124 on the inner face 120 is arranged to sealingly engage the corresponding sealing element 124 on the inner end face 120 of an opposing closure element.

In some examples the closure elements may not necessarily provide a sealing function. Instead, the closure elements may function to grip an object (such as a tubular) which extends through the closure apparatus. An example of a gripping closure element 216 is illustrated in Figure 9. In this case the closure element 216 includes a recess region 222 which includes a gripping insert 56 having a serrated profile which grips or bites into an outer surface of an object, such as a tubular. In this respect the gripping function of the closure element 216 may be improved by a more efficient application or use of the available actuation force due to the linear movement (without rotation) of the closure element 216 during a second movement phase.

In a further example the closure elements may function to cut through an object located within a bore of the closure apparatus. An example pair of closure elements capable of providing a cutting function is illustrated in Figure 10, with a first closure element of the pair being identified by reference numeral 316a, and a second closure element of the pair being identified by reference numeral 316b. Each closure element 316a, 316b may be substantially similar to the blind ram closure element 116 of Figure 8, in that each comprises an upper face 318a, 318b, inner face 320a, 320b and a continuous seal member 324 a, 324b.

The first closure element 316a includes a first cutting blade 58, and the second closure element 316b includes a second cutting blade 60, wherein the first and second blades 58, 60 are arranged to cooperate to cut through an object positioned therebetween by a shearing action. An undercut region 62 is provided below the first cutting blade, and a recessed pocket 64 is provided above the second cutting blade. The undercut region 62 and recessed pocket 64 permit the blades 58, 60 be nested together when the closure elements 316a, 316b are in a closed position.

The second closure element 316b further includes tapered guide ribs 66, and the first closure element includes rib pockets 68 which receive the ribs 66 when the closure elements 316a, 316b are in a closed position. As will be described in further detail below, the guide ribs 66 function to centralise an object between the closure elements 316a, 316b during a closing and cutting operation. To further assist with the centralising effect, the first cutting blade 58 also has a tapered profile, with outer tapering positions converging towards a central location of said blade 58.

A sequential closing operation of the closure elements 316a, 316b of Figure 10 will be described with reference to Figures 11 to 15, with the closure elements 316a, 316b shown removed from an associated closure apparatus for clarity.

Referring initially to Figure 11, the closure elements 316a, 316b are provided in an open position, and subsequently rotated in a first movement phase (in the same manner described previously) to an intermediate position of Figure 12. When in this intermediate position the blades 58, 60 do not yet laterally overlap, and cutting of an object (not illustrated for clarity) may not have begun. Depending on the type and geometry of the object, some flattening/crushing of the object may have occurred. Figure 13 illustrates the first and second closure elements 316a, 316b in the configuration of Figure 12, from above. In this case the taper of the guide ribs 66 and of the first cutting blade 58 is such that any object is guided to be centralised between the cutting blades 58, 60.

The first and second closure elements 316a, 316b may subsequently be moved in a second movement phase comprising only relative linear movement (in the same manner previously described), to allow the cutting blades 58, 60 to overlap and shear through any object located therebetween, as illustrated in Figure 14. Once the object is cut gravity may allow the object to fall below the closure elements 316a, 316b, with subsequent further movement in the second movement phase allowing the first and second closure elements 316a, 316b to be fully closed together, as illustrated in Figure 15, energising the seal elements 324a, 324b (against each other and against other sealing components, such as sealing seat 28 of Figure 1).

In an alternative example the first and second closure elements 316a, 316b may be modified to engage and seal around the cut component. In this respect, the closure elements 316a, 316b may define a suitable profile or recess to accommodate the cut object.

In an alternative example, the closure elements may be configured to cut without subsequent sealing. One or both of the closure elements may include a suitable recess or relief region to accommodate the cut object.

In the example illustrated above the closure apparatus 10 includes a single set of closure elements, operating together at a single axial location. However, in other examples a closure apparatus may comprise multiple sets of closure elements provided at different axial locations. Each set of closure elements may provide the same or different functions. In one example, illustrated in cross-section in Figure 16, a closure apparatus 410 includes a housing 412 defining a bore 414 extending axially therethrough. As in the closure apparatus 10 first illustrated in Figure 1, the present example closure apparatus 410 includes a set of closure elements 416 which function to close and seal against a tubing 454 extending along the bore 414 of the apparatus 10. The form and operation of the closure elements 416 and associated equipment is similar to the example first shown in Figure 1, and as such no further description will be provided for brevity.

In the present example the closure apparatus 410 further includes a second set of closure elements 70, which are provided in the form of gripping closure elements, similar to closure element 216 shown in Figure 9. The gripping closure elements 216 may be operated in the same manner as previously described, and as such no further description will be given, except to say that the gripping closure elements 70 are operated to move to their closed positon to grip the tubular 454. In the present example various by-pass flow channels and ports 72 are provided around the gripping closure elements 70 to permit suitable flow area past said elements 70 when closed.

It will be recognised that the gripping closure elements 70 of the closure apparatus 410 are provided in an inverted position relative to the sealing closure elements 416. In this respect certain operational parameters may dictate a preference of such mounting direction. In the present example the griping closure elements 70 may function to carry the weight, or at least a portion of the weight of the tubing 454. When the elements 70 are thus engaged, the weight applied may generate a bias force on the elements 70 which increases gripping strength. Similarly, in certain examples of sealing closure elements, a pressure differential applied in one direction may generate a similar bias force. The sealing closure elements may be arranged to permit this bias force to increase, or indeed disrupt, the sealing effect.

It should be understood that the examples provided herein are indeed merely exemplary of the present disclosure, and that various modifications may be made. For example, any number of closure elements may be provided, from a single closure element, two as in some of the examples illustrated, three, four etc. Further, the closure apparatus according the principles exemplified herein may be used in multiple applications, such as within well control equipment which may be located at a wellhead, on a drilling facility, production facility etc., within a wellbore and the like.

Further, a single closure element may be provided to perform multiple different functions.

Claims

1. A closure apparatus for providing a closing function within a bore, comprising: a housing defining a bore extending axially therethrough;

a closure element moveable from an open position in which the closure element is retracted from the bore and a closed position in which the closure element is extended into the bore;

2. The closure apparatus according to claim 1, wherein the actuator comprises a linear actuator arranged to stroke along a linear stroke path.

3. The closure apparatus according to claim 2, wherein the orientation of the linear stroke path is fixed during operation of the actuator.

4. The closure apparatus according to claim 2 or 3, wherein the interface mechanism is arranged such that the linear operation applied by the actuator is converted to a rotational movement of the closure element during the first movement phase, and that the linear operation applied by the actuator provides only linear movement of the closure element during the second movement phase.

5. The closure apparatus according to any preceding claim, wherein the linear movement of the closure element during the second movement phase is provided along a path of movement which is aligned or parallel with the stroke path of the actuator.

6. The closure apparatus according to any preceding claim, wherein the interface mechanism permits the first and second movement phases to be achieved during a single operation of the actuator.

7. The closure apparatus according to any preceding claim, wherein the interface mechanism provides a transition movement phase between the first and second movement phases.

8. The closure apparatus according to any preceding claim, wherein the closure element is moveable from its closed position to its open position.

9. The closure apparatus according to any preceding claim, wherein the actuator is coupled to the closure element via a pivot connection, wherein the pivot connection permits the closure element to be rotated during the first movement phase.

10. The closure apparatus according to claim 9, wherein the pivot connection between the actuator and the closure element is moveable in space during operation of the actuator.

11. The closure apparatus according to claim 10, wherein the path of movement of the pivot connection is aligned with the stroke path of the actuator.

12. The closure apparatus according to any preceding claim, wherein the closure element defines a point of interface with the interface mechanism, the interface mechanism controlling the movement of the point of interface along a predetermined locus path to facilitate the desired movement of the closure element during operation of the actuator.

13. The closure apparatus according to claim 12, wherein the predetermined locus path comprises a first locus component, wherein the interface point of the closure element moves along the first locus component during the first movement phase.

14. The closure apparatus according to claim 13, wherein the first locus component is arranged laterally to the stroke path of the actuator.

15. The closure apparatus according to claim 13 or 14, wherein the predetermined locus path comprises a second locus component, wherein the interface point of the closure element moves along the second locus component during the second movement phase.

16. The closure apparatus according to claim 15, wherein the second locus component is aligned with the stroke path of the actuator.

17. The closure apparatus according to any one of claims 12 to 16, wherein the point of interface is radially disposed from the connection between the closure element and the actuator to permit a turning moment to be generated which allows the closure element to be rotated during the first movement phase.

18. The closure apparatus according to any preceding claim, wherein the interface mechanism is provided at a single location within the apparatus, and provides movement control of the closure element in the first and second movement phases from said single location.

19. The closure apparatus according to claim 18, wherein at least a first portion of the interface mechanism for controlling the first movement phase and at least a second portion of the interface mechanism for controlling the second movement phase are provided at a common location within the apparatus.

20. The closure apparatus according to any preceding claim wherein the interface mechanism is formed over different locations within the apparatus.

21. The closure apparatus according to any preceding claim, wherein at least a first portion of the interface mechanism for controlling the first movement phase is provided at a first location within the apparatus, and at least a second portion of the interface mechanism for controlling the second movement phase is provided at a second location within the apparatus.

22. The closure apparatus according to any preceding claim, wherein the interface mechanism comprises a track and follower arrangement interposed between the housing and closure element, the track and follower arrangement comprising interfacing track and follower features.

23. The closure apparatus according to claim 22, wherein the track feature comprises first and second track components arranged in different directions, wherein the first track component defines the first movement phase of the closure element, and the second track component defines the second movement phase of the closure element.

24. The closure apparatus according to claim 23, wherein the first track component extends in a direction which is lateral to the stroke path of the actuator to permit a turning moment to be generated during operation of the actuator.

25. The closure apparatus according to claim 23 or 24, wherein the second track component extends in a direction which is aligned with the stroke path of the actuator to control the closure element to move linearly without further rotation during the second movement phase.

26. The closure apparatus according to any one of claims 23 to 25, wherein the track feature comprises a transition component between the first and second track components.

27. The closure apparatus according to any preceding claim, comprising a retaining arrangement for retaining the closure element in its closed position.

28. The closure apparatus according to any preceding claim, wherein the closure element provides sealing within the bore when the closure element is in its closed position.

29. The closure apparatus according to any preceding claim, wherein the closure element comprises a sealing arrangement.

30. The closure apparatus according to any preceding claim, comprising a sealing seat which circumscribes the bore, the closure element being operable to sealingly engage the sealing seat when the closure element is in its closed position.

31. The closure apparatus according to any preceding claim, wherein the closure element cooperates with one or more other closure elements to close and seal the bore.

32. The closure apparatus according to any preceding claim, wherein the closure element provides sealing within the bore with an object therein, said closure element providing a seal against the object.

33. The closure apparatus according to any preceding claim, wherein the closure element provides a support function within the bore when the closure element is in its closed position.

34. The closure apparatus according to claim 33, wherein the closure element grips an object extending through the bore when the closure element is in its closed position.

35. The closure apparatus according to any preceding claim, wherein the closure element provides a cutting function within the bore.

36. The closure apparatus according to claim 35, wherein the closure element is arranged to cut an object located within the bore.

37. The closure apparatus according to claim 35 or 36, wherein the closure element comprises a cutting element.

38. The closure apparatus according to any one of claims 35 to 37, wherein the closure element cooperates with one or more other closure elements to cut an object within the bore.

39. The closure apparatus according to any preceding claim, comprising multiple closure elements.

40. The closure apparatus according to any preceding claim, configured for use with a wellbore.

41. A method for providing a closing function within a bore, comprising:

operating an actuator to move a closure element from an open position in which the closure element is retracted from the bore to a closed position in which the closure element is extended into the bore; and

5 controlling the closure element via an interface mechanism to move from its open position to its closed position in sequential first and second movement phases during operation of the actuator, wherein the first movement phase comprises a rotating motion of the closure element from its open position to an intermediate position, and the second movement phase comprises a linear movement without

10 rotation from the intermediate position to its closed position.