TECHNICAL FIELD AND BACKGROUND

The present disclosure relates to a subsea actuator tool for actuating a component, such as valve of a subsea tree, and a method of operating such a tool, e.g. by means of an underwater vehicle.

Underwater vehicles have various applications in deep water industries such as offshore hydrocarbon extraction. Most commonly used are unmanned underwater vehicles (UUV) which are vehicles that are able to operate underwater without a human occupant. These vehicles may be divided into categories including remotely operated underwater vehicles (ROVs), which are controlled by a remote human operator, and autonomous underwater vehicles (AUVs), which operate independently of direct human input.

A“subsea tree” or“Christmas tree” is a subsea structure with valves, spools, and fittings used in the field of petroleum and natural gas extraction. An underwater vehicle can be equipped with manipulator arms to handle a subsea tool for interacting with components of the subsea structure. Typically, the subsea structure has a particularly shaped interfaces to allow a connection mechanism of the subsea tool to engage and lock on to the respective interface.

Once locked on to the interface, parts of the tool may be actuated to manipulate a corresponding component, e.g. valve of the subsea tree. For example, a Linear Actuator Override Tool (LAOT), also referred to as a Linear Valve Override Tool (LVOT), is a subsea tool designed to actuate a valve stem in a subsea tree by pushing a (piston) rod of the tool into a corresponding valve interface while keeping the rest of the tool secured via the locking mechanism. The tool typically comprises a profile that acts as the locking mechanism with the valve interface to keep the tool secured in reaction to the axial override force generated by the tool piston rod. For example, international standard ISO 13628-8:2002 (confirmed in 2015) gives functional requirements and guidelines for ROV interfaces on subsea production systems for the petroleum and natural gas industries.

One type of locking mechanism (e.g. compatible with ISO 13628-8 Type B interface) has a horseshoe interface profile on the tool that can slide over an outward flange of the valve interface. However, high actuation forces of the tool may deteriorate structural integrity of such asymmetrical profiles.

Other types of locking mechanisms (e.g. compatible with ISO 13628-8 Type A or C interface) may involve more symmetrical collet shapes such as a bayonet profile comprising multiple inward teeth and slots. However, such interfaces may be difficult to operate typically requiring more precise alignment of the tool with corresponding outward slots and teeth on the valve flange interface and/or twisting of the tool for locking the interface.

U.S. patent publication number 2005/0146137 Al relates to mechanical joints for subsea equipment and discloses a mechanical connector for an oil and gas well apparatus which comprises a plurality of fingers which are located circumferentially around a pair of pipe flanges and which each include a finger reaction surface, a stationary retainer ring against which each finger reaction surface is pressed, and a runner ring which is located radially outside the fingers and is movable lengthwise along the fingers by an actuator. However, the known connector may be difficult to operate in combination with a subsea actuator tool which may be placed and removed many times, e.g. by means of an underwater vehicle.

For these and other consideration, it is desired to provide an improved connection mechanism for subsea tools, optimizing a combination of structural integrity with easy of operation.

SUMMARY

Aspects of the present disclosure relates to a subsea actuator tool for actuating a component of a subsea structure and methods of installing such tool onto an interface of the subsea structure. Typically, the actuator tool comprises a connection mechanism for locking the actuator tool onto the connection interface of the subsea structure while actuating the component. As described herein, the connection mechanism comprises a plurality of fingers, also referred to as“collet fingers” or“dogs”, which are located circumferentially around a central axis. Each of the fingers is configured to switch between a closed position wherein the respective fingers are configured latch onto the connection interface for forming a respective connection therewith, and an open position wherein the respective fingers are configured to release their respective connection with the connection interface. Advantageously, a connection interface with circumferentially arranged fingers may be relatively easy to install while providing an even distribution of forces around the connection interface. For example, by providing the connection interface the capability of snapping onto the interface of the subsea structure, the tool can be more easily placed e.g. using only one manipulator arm of an underwater vehicle to operate the connection interface.

BRIEF DESCRIPTION OF DRAWINGS

These and other features, aspects, and advantages of the apparatus, systems and methods of the present disclosure will become better understood from the following description, appended claims, and accompanying drawing wherein:

FIGs 1A and IB illustrate perspective front and back views of an embodiment of an actuator tool with a mechanically operated switching mechanism;

FIGs 2A and 2B illustrate perspective front and back views of an embodiment of an actuator tool with a hydraulically operated switching mechanism; FIG 3A illustrates a cross-section view of an embodiment of an actuator tool in an armed configuration;

FIG 3B illustrates a front view of the embodiment in the armed configuration;

FIG 3C illustrates a perspective view of parts of the switching mechanism of the embodiment in the armed configuration;

FIG 3D illustrates a close-up view of the switching mechanism in the armed configuration;

FIGs 4A-4D illustrate similar views of the embodiment as FIGs 3A-3D, but now in the locked configuration;

FIGs 5A-5D illustrate similar views of the embodiment as FIGs 3A-3D and 4A-4D, but now in the unlocked configuration;

FIGs 6-10 illustrate side and perspective views for example operation, including installing and removing the actuator tool from a subsea structure;

FIGs 11A and 11B illustrate side views of another embodiment of an actuator tool with another mechanically operated switching mechanism;

FIGs 12A and 12B illustrate side and perspective views of a combination of a Linear Actuator Override Tool (LOAT) attached to a Linear Lockout Tool (LLT);

FIG 13A illustrate a sided view of another combination of a LOAT and LLT;

FIG 13B illustrates a close-up view of a locking mechanism of the

LLT.

DESCRIPTION OF EMBODIMENTS

Terminology used for describing particular embodiments is not intended to be limiting of the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The term "and/or" includes any and all combinations of one or more of the associated listed items. It will be understood that the terms "comprises" and/or "comprising" specify the presence of stated features but do not preclude the presence or addition of one or more other features. It will be further understood that when a particular step of a method is referred to as subsequent to another step, it can directly follow said other step or one or more intermediate steps may be carried out before carrying out the particular step, unless specified otherwise. Likewise it will be understood that when a connection between structures or components is described, this connection may be established directly or through intermediate structures or components unless specified otherwise.

The invention is described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. In the drawings, the absolute and relative sizes of systems, components, layers, and regions may be exaggerated for clarity.

Embodiments may be described with reference to schematic and/or cross- section illustrations of possibly idealized embodiments and intermediate structures of the invention. In the description and drawings, like numbers refer to like elements throughout. Relative terms as well as derivatives thereof should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description and do not require that the system be constructed or operated in a particular orientation unless stated otherwise.

FIGs 1A and IB illustrate perspective front and back views of an embodiment of a subsea actuator tool 100 comprising a mechanically operated switching mechanism 116,117. FIGs 2A and 2B illustrate a similar embodiment of an actuator tool 100, but with a hydraulically operated switching mechanism 116,117h.

Typically, the actuator tool 100 comprises a connection mechanism 110 for locking the actuator tool 100 onto a connection interface such as a flange of a subsea structure while actuating a component. In a preferred embodiment, e.g. as shown, the connection mechanism 110 comprises a plurality of fingers 111,112. The fingers are located

circumferentially around a central axis“X”. As will be further illustrated with reference to FIG 3— 5 below, each of the fingers 111,112 is configured to pivot radially inward or outward for switching between a closed position “C” and an open position“O”. In the closed position“C”, the respective fingers 111,112 are configured to latch onto a connection interface such as a flange for forming a respective connection therewith. In the open position “O”, the respective fingers 111,112 are configured to release their respective connection with the connection interface.

In a preferred embodiment, as illustrated in FIGs 3A-3D, the actuator tool 100 is operable in an armed configuration“A”. When the tool is switched to the armed configuration, at least some of the fingers 111 are biased with a predefined biasing force pushing the biased fingers 111 to the closed position“C”. In one embodiment, as particularly shown in the cross- section view of FIG 3A, the connection mechanism 110 comprises a biasing means lllr, e.g. spring mechanism and/or elastic material. For example, the biasing means are configured to directly or indirectly push the biased fingers 111 closed with a predefined biasing force Fb (indicated by an arrow) when the actuator tool 100 is set to operate in the armed configuration“A”. Accordingly, the biased fingers 111 are sprung closed in the armed configuration“A”. Preferably, the biasing force Fb can be overcome by an external force, in particular by a contact force between the connection interface 210 and the biased fingers 111 when the front of the actuator tool 100 is pushed there against, allowing the biased fingers 111 to be

momentarily pushed to the open position. Accordingly, in the armed configuration“A”, the connection mechanism 110 is configured to

momentarily open the biased fingers 111 and snap onto the connection interface 210 when the actuator tool 100 is frontally pushed against, e.g. a flange that is part of the connection interface 210 of the component.

In one embodiment, the fingers, or at least the biased fingers 111, comprise a tapered front profile configured to open, e.g. spread out, the biased fingers 111 counteracting the biasing force Fb when pushed against the connection interface 210. Alternatively, or in addition, also the connection interface 210 may comprise a tapered profile to push the biased fingers 111 open (not shown).

In some embodiments, depending on the connection interface 210, the fingers 111,112, biased or otherwise, each comprise a frontal hook profile configured to latch onto a rim or flange profile of the connection interface 210. For example, the fingers 111,112 each comprise a radially inward frontal hook profile configured to latch onto an outward flange profile of the connection interface 210. In other or further embodiments, in the armed configuration“A”, the biasing force Fb is predefined such that, when the tapered front profiles of the biased fingers 111 are pushed against a rim of the connection interface 210, the biased fingers 111 are allowed to spread to the open position“O” counteracting the biasing force Fb; and when the frontal hook profiles of the biased fingers 111 are pushed beyond the rim of the connection interface 210, the biased fingers 111 are pushed by the biasing force Fb back to the closed position“C”.

In one embodiment, the connection mechanism 110 is configured to lock the actuator tool 100 at least onto a flange interface, e.g. as defined by the international standard ISO 13628-8:2006 Type B interface. In another or further embodiment, the connection mechanism is adapted to additionally or alternatively connect to other interfaces, e.g. also on a Type A and/or Type C interface of that standard. For example, a connection interface 210 of Type A has a profile comprising a flange with a flange diameter of 187 mm and 30 mm flange thickness, wherein the flange is connected to a cylinder with a 127 mm outer cylinder diameter, wherein the flange and cylinder comprise a central opening with 55 mm diameter. Of course the connection mechanism can also be adapted to fit other connection interfaces.

In a preferred embodiment, as shown e.g. in the front view of FIG 3B, in the armed configuration“A”, at least three of the fingers are biased to the closed position“C”. In another or further preferred embodiment, in the armed configuration“A”, at least some of the fingers are forced to the open position“0”. In other words, in the armed configuration“A”, preferably not all of the fingers are biased in the closed position“C”. Accordingly, in the armed configuration“A”, a first subset of fingers 111 may be biased to the closed position“C” and a second subset of fingers 112 may be forced in the open position“O”. For example, in the armed configuration“A”, at least three of the other fingers are positioned or forced in the open position“O”, preferably more, e.g. at least six or at least nine. Most preferably, the second subset 112 contains an integer multiple number of fingers relative to the first subset 111. Also preferably, the biased fingers 111 are distributed equidistantly around a circumference of the central axis“X”.

In a preferred embodiment, as shown in FIGs 4A-4D, the actuator tool 100 is operable in a locked configuration“L” wherein all the fingers 111 are forced to the closed position“C”. For example, the fingers 111,112 are configured to radially pivot inward to the closed position“C” (e.g. shown in FIG 4A) and radially pivot outward to the open position“O” (e.g. shown in FIG 5A).

In some embodiments, as shown particularly in the cross-section of FIG 4A, the actuator tool 100 comprises a runner ring 113 movable along the central axis“X” and comprising an inner profile configured to run over an outer profile of the fingers 111,112. Accordingly, the runner ring 113 exerts a fore on the fingers so as to pivot the fingers between the closed position“C” and open position“O” depending on an axial position of the runner ring 113 with respect to the fingers 111,112. For example, the inner profile of runner ring 113 has an inner minimum diameter configured to radially fit around an outer circumference of the fingers 111,112 in the closed position“C” to prevent the fingers from opening and maintain the locked configuration“L” when the runner ring 113 is moved to a front of the actuator tool 100 around the fingers 111,112.

In some embodiments, as also shown in FIG 4A, the actuator tool 100 comprises a retainer ring 114 for engaging an inner profile of the fingers 111,112. Accordingly the fingers 111,112 are configured to pivot around and/or radially press against the retainer ring 114. For example, as shown, the retainer ring 114 forms a flange profile at a front of the actuator tool 100. In some embodiments, the fingers 111,112 comprise a lateral hook profile configured to stay latched behind the flange profile formed by the retainer ring 114 and, e.g. in combination with the runner ring 113, keep the fingers attached to the actuator tool 100. In other or further

embodiments, the fingers 111,112 comprise a frontal a lateral hook profile which in use keeps a flange profile formed by the retainer ring 114 and a flange profile of the connection interface 210 together when the fingers are biased or forced in the closed position“C”. In the embodiment shown, the retainer ring 114 is fixed relative to the moveable runner ring 113 and/or the fingers 111,112. For example, the retainer ring 114 is fixed to a hull or main body 101 of the actuator tool 100. Preferably, the retainer ring 114 is fixed by a threaded profile, e.g. screwed onto the main body 101.

In some embodiments, as also shown in FIG 4A, the actuator tool 100 comprises an abutment surface 112s, e.g. provided by a reaction ring, at positions of the non-biased fingers 112. Preferably, the abutment surface 112s is configured to keep the non-biased fingers 112 in the open position “O”, e.g. in combination with the inner profile of the runner ring 113 and/or the profile of the retainer ring 114. Typically, the actuator tool 100 comprises an actuator mechanism for actuating a component while the actuator tool 100 is locked onto the connection interface 210, i.e. when the fingers are in the closed position. In one embodiment, the actuator tool 100 comprises an actuator rod 121 extendible along the central axis“X” from a front side of the actuator tool 100 relative to the fingers 111,112, e.g. for directly or indirectly actuating the component 220, possibly through interaction with intermediate elements. For example, the connection interface 210 comprises a central opening, e.g. cylinder with a flange, through which the actuator rod 121 may extend into the connection interface 210 for actuating the component 220. For example, the component 220 is a valve and the actuator rod 121 is configured to actuate a valve stem 221 inside the connection interface 210 of the valve as shown in FIG 4A.

In some embodiments, as also visible e.g. in FIG 1A or IB, the actuator tool 100 comprises an alignment guide 115 for centering the central axis“X” with respect to the connection interface 210. For example, the alignment guide 115 fits into a central opening of the connection interface 210. Preferably, the alignment guide 115 comprises a tapered profile tapering inward towards the front side of the actuator tool 100. In the embodiment shown, the alignment guide 115 comprises a central opening allowing the actuator rod 121 to extend from the alignment guide 115.

In some embodiments, particularly in the locked configuration “L”, the closed fingers 111,112 are configured to keep the actuator tool 100 fixated relative to the connection interface 210 of the subsea structure 200 while an actuator rod 121 extends towards or into the subsea structure 200 to actuate the component 220. Preferably, the actuator rod 121 is configured to be hydraulically operated. For example, the actuator rod 121 comprises a piston configured to move in an inner chamber 122 of the actuator tool 100. For example, a pressure supply channel 127 is arranged to apply pressure in the chamber to push the piston out from the front of the actuator tool 100. In some embodiments, as shown e.g. in FIG IB, the actuator tool 100 comprises a so-called hotstab receptacle port 125 for receiving pressure from an external hydraulic pump. For example, the pressure is generated by a hydraulic pump in an underwater vehicle (not shown) operating the actuator tool 100. For example, the pressure supply channel 127 is configured to receive pressure via the hotstab receptacle port 125 from the underwater vehicle. In other or further embodiments, also shown in FIG IB, the actuator tool 100 comprises a hydraulic switch 126 for maintaining pressure inside, e.g. in case the external hydraulic pump is disengaged from the hotstab receptacle port 125. This allows the actuator tool 100 to be left behind on the subsea structure while keeping the component actuated, e.g. keeping a valve open (or closed).

In a preferred embodiment, as shown in FIGs 5A-5D, the actuator tool 100 is operable in an unlocked configuration“U” wherein all the fingers 111 are forced in the open position“O”. For example, in the unlocked configuration“U”, the biasing force (shown in FIG 4A) is deactivated or counteracted forcing also the otherwise biased fingers 111 to the open position“O”

As shown e.g. in FIGs 3C,4C, and 5C, the actuator tool 100 may comprise a switching mechanism for switching the actuator tool 100 between at least three different configurations including an armed

configuration“A”, a locked configuration“L”, and an unlocked configuration “U”. For example, as shown, the actuator tool 100 is switchable from the unlocked configuration“U” to the locked configuration“L” via the armed configuration“A” intermediate there between, and vice versa. Preferably, the switching mechanism is mechanically operable, e.g. by manipulator arms of an underwater vehicle moving one or more handles 116,117 on the actuator tool 100, as shown in the embodiment of FIG 1.

In some embodiments, the switching mechanism for switching between the armed configuration“A” and the locked configuration“L” is operable by moving a first handle 116. In other or further embodiments, the switching mechanism for switching between the armed configuration“A” and the locked configuration“L” is operable by moving a second handle 117. In one embodiment, as shown e.g. in FIG 5C, the first handle 116 is operable by rotation R of the first handle 116 around an axis Y transverse to the central axis“X”. In the embodiments of FIGs 3-5, the second handle 117 is operated by axially moving the second handle 117 along the central axis“X”. In some embodiments, the second handle 117 is configured to move the runner ring 113 along the central axis“X” with respect to the fingers

111,112 or vice versa. For example, the second handle 117 is connected to the runner ring 113. In some embodiments, e.g. as shown, the second handle 117 is separate from the first handle 116. Alternatively, one handle may cause all switching. In one embodiment, as shown in FIGs 11A and 11B, a switching handle is configured to move the runner ring 113 by pivoting the handle forward or backward, instead of translating. Accordingly the mechanically switching between different configurations may involve any combination of translating, pivoting and/or rotating handles.

Alternatively, or in addition to a mechanical switching mechanism, the switching mechanism may be partially or wholly operable by a hydraulic switching mechanism 117h, as shown in the embodiment of FIG 2. In one embodiment, the actuator tool 100 is configured to switch from the unlocked configuration“U” to the armed configuration“A” upon application of a first hydraulic pressure. In another or further embodiment, the actuator tool 100 is configured to switch from the armed configuration “A” to the locked configuration“L” upon application of a second hydraulic pressure. In another or further embodiment, the actuator tool 100 is configured to actuate the actuator rod 121 upon application of a third hydraulic pressure. For example, the hydraulic pressure may be increased in different steps to cause the actuator tool 100 to sequentially switch between different modes“U”,”A”,”L” and/or actuate the actuator rod 121 while the actuator tool 100 is in the locked configuration“L”. Alternatively, or additionally, the actuator tool 100 may also comprise hydraulic switches to switch the different configuration.

In some embodiment the switching is performed by a hydraulic sequential method. For example the switching may occur from the unlocked configuration“U” to the locked configuration“L”, e.g. via the armed configuration“A”. Alternatively, the hydraulic sequential method may directly switch from the locked configuration“L” to the unlocked

configuration“U”, or vice versa without any armed configuration“A” there between. In one example, the armed configuration“A” may be entirely omitted. Accordingly, an actuator tool 100 as described herein can be envisioned, but without the armed configuration“A”, e.g. omitting the biasing mechanism and using only non-biased fingers 112.

In one embodiment, as illustrated with reference to FIGs 3C,4C,5C, the switching mechanism comprises a cam mechanism 118. For example, as particularly visible in the enlarged views of FIGs 3D,4D,5D, the cam mechanism 118 may comprise a slot profile 118s configured to guide a cam follower 118f. For example, a first part of the slot profile 118s extends parallel to the central axis“X” to guide the cam follower 118f between the armed configuration“A” and the locked configuration“L”. For example, a second part of the slot profile 118s extends at an angle with respect to first part to guide the cam follower 118f partially inward, or outward (not shown), while also moving further along the central axis“X”. As shown e.g. in FIG 5C, the cam follower 118f can be connected to the rotatable first handle 116 causing the cam follower 118f to be pulled inward (or outward, not shown) when rotating the handle while further pushing back the runner ring 113 with respect to the fingers 111,112 causing the switch from the armed configuration“A” to the unlocked configuration“U”. FIGs 6-10 illustrate successive steps of example operation for the actuator tool 100 as described herein.

In some embodiments, as shown in FIGs 6 and 7, the actuator tool 100 as described herein is installed onto a connection interface 210 of a subsea structure 200. For example, the actuator tool 100 is set to an armed configuration“A” wherein at least some of the fingers are biased with a predefined biasing force to the closed position; a tapered front profile of the biased fingers is pushed against a rim of the connection interface 210 causing the biased fingers to the open position temporarily counteracting the biasing force; and a frontal hook profile of the biased fingers is pushed beyond the rim of the connection interface 210, wherein the biased fingers are pushed by the biasing force back to the closed position. In other or further embodiments, as shown in FIG 8, the tool is set to a locked

configuration“L”, wherein all the biased fingers are forced to the closed position. In some embodiments (not shown here), hydraulic pressure is supplied to the actuator tool 100 to actuate an actuator rod while the actuator tool 100 is locked onto the connection interface 210. In other or further embodiments. Afterwards, as shown in FIG 9, the actuator tool 100 can be switched back from the locked configuration to the unlocked configuration“U” to remove the actuator tool 100 from the connection interface 210.

In a preferred embodiment, the subsea actuator tool 100 is remotely and/or automatically operable e.g. by one or more manipulator arms 302 of an underwater vehicle, e.g. a remotely operated vehicle (ROV) or Autonomous Underwater Vehicles (AUV). For example,, the actuator tool 100 is manufactured from material such as Grade5 Titanium with good strength to weight ratio to cope with high linear valve override forces but yet be light enough to be handle-able e.g. by the ROV manipulators. For example, the actuator tool 100 is installed by an underwater vehicle comprising a first manipulator arm 301 and a second manipulator arm 302. In a preferred embodiment, the installing of the actuator tool 100 is handled entirely by the first manipulator arm 301 while the second manipulator arm 302 keeps the underwater vehicle attached to the subsea structure 200. For example, the first manipulator arm 301 switches the actuator tool 100 from the armed configuration“A” to the locked configuration“LT after the actuator tool 100 is pushed onto the connection interface 210. Afterwards, the first manipulator arm 301 can switch the actuator tool 100 from the locked configuration“L” to the unlocked configuration“U” to remove the actuator tool 100 from the connection interface 210.

In the embodiment as illustrated by FIGs 6A and 6B the actuator tool 100 is armed and ready to installed. For example, the embodiment comprises one or more of the following steps. The underwater vehicle grabs with the second manipulator arm 302, the ROV handle 202 on the subsea structure 200. The underwater vehicle (i.e. its manipulator arm 301) grabs the front handle 116 on the actuator tool and removes the tool e.g. from a deployment basket (not shown). The actuator tool 100 is deployed in the armed configuration“A”— for example, three fingers are sprung closed and nine fingers are fully open. The underwater vehicle flies the tool into approximate alignment position with the valve interface 210.

In the embodiment as illustrated by FIGs 7 A and 7B the actuator tool 100 is snapped onto the connection interface 210. For example, the embodiment comprises one or more of the following steps. The underwater vehicle while still holding the front handle 116 moves the actuator tool 100 forward and engages the three tapered sprung closed fingers and the alignment guide (not visible here) onto the connection interface 210. It will be appreciated that, at this point, the underwater vehicle can release the front handle 116 on the actuator tool 100 and position the manipulator on the rear handle 117.

In the embodiment as illustrated by FIGs 8A and 8B the actuator tool 100 is locked onto the connection interface 210. For example, the embodiment comprises one or more of the following steps. With the underwater vehicle manipulator gripping the rear handle 117 of the actuator tool 100, the underwater vehicle moves the manipulator arm 301 forward to slide the runner ring or collar forward from the armed

configuration to the locked configuration“L”.

In the embodiment as illustrated by FIGs 9A and 9B the actuator tool 100 is being removed but still in the armed configuration“A” . For example, the embodiment comprises one or more of the following steps.

Following some time in operation the actuator tool 100 is removed from the connection interface 210. The underwater vehicle moves the manipulator arm 301 backwards holding the rear handle 117 to slide the runner ring from the locked position to the armed configuration“A”.

In the embodiment as illustrated by FIGs 10A and 10B the actuator tool 100 is unlocked and removed from the connection interface 210 For example, the embodiment comprises one or more of the following steps. The underwater vehicle now removes the tool from the client interface. The underwater vehicle releases the rear handle 117 and moves the first manipulator arm 301 to grab the front handle 116. The underwater vehicle now rotates the front handle 116, e.g. forty-five degrees which actuates the cam mechanism and moves the runner ring from the armed configuration to the unlocked configuration“U” releasing the three sprung fingers. The actuator tool 100 is now completely removed from the connection interface 210.

FIGs 12A and 12B illustrate side and perspective views of a combination of one actuator tool embodied as a Linear Actuator Override Tool (LOAT) attached to another actuator tool embodied as a Linear Lockout Tool (LLT). It will be appreciated that the actuator tool as described herein can be configured to directly or indirectly actuate a valve of a subsea tree. Typically, the LOAT comprises a hydraulically actuated piston rod 121 that is actuated by hydraulic pressure to extend from the tool. Typically, the LLT comprises a mechanically actuated rod (not visible) which can extend from the tool. For example, a backside of the LLT is open allowing the rod to be actuated by a LOAT connected to the backside having a similar profile as the connection interface of the subsea structure.

FIG 13A illustrate a sided view of another combination of a LOAT and LLT. FIG 13B illustrates a close-up view of a locking mechanism of the LLT. In some embodiments, the LLT comprises a mechanical locking mechanism 121L to lock the extended rod in the actuated position. In this way hydraulic pressure does not need to be maintained on the tool. For example, the LLT has a locking mechanism similar to door or a gate bolt, e.g. the mechanism is pushed and then rotated into a locked position. In a preferred embodiment, the LLT has a female interface matching the mail interface of the LAOT at the front of it and a corresponding male interface at front of the tool. As illustrated, the LLT can be engaged onto a linear valve interface and the LAOT can in turn be engaged onto the LLT. The LAOT piston is e.g. stroked out under hydraulic pressure, e.g. supplied by an ROV, which pushes against the actuation shaft in the LLT. Once the piston and shaft are fully stroked, the ROV can rotate the actuator shaft into a slot and then removes hydraulic pressure from the LAOT allowing the linear valve spring to force the LLT’s shaft back against a shoulder, keeping the valve locked open. The LAOT can then be removed and is available for some other ROV operation.

For the purpose of clarity and a concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include

embodiments having combinations of all or some of the features described.

In interpreting the appended claims, it should be understood that the word "comprising" does not exclude the presence of other elements or acts than those listed in a given claim; the word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements; any reference signs in the claims do not limit their scope; several "means" may be represented by the same or different item(s) or implemented structure or function; any of the disclosed devices or portions thereof may be combined together or separated into further portions unless specifically stated otherwise. Where one claim refers to another claim, this may indicate synergetic advantage achieved by the combination of their respective features. But the mere fact that certain measures are recited in mutually different claims does not indicate that a combination of these measures cannot also be used to advantage. The present embodiments may thus include all working combinations of the claims wherein each claim can in principle refer to any preceding claim unless clearly excluded by context.