Technical Field

The present disclosure relates to a subsea actuation system with a retrievable position indicator. More particularly, the present disclosure relates to a subsea actuation system with a retrievable position indicator, that is at least partly retrievable, where the subsea actuation system is connectable to a subsea structure with a valve, preferably used in the oil and gas industry. The position indicator indicates the position of the valve.

Background

A subsea actuation system is used for operating a valve on a valve assembly, such as a subsea X-mas tree. An retrievable actuator is used to connect to the subsea actuation system to operate the valve. The subsea actuation system has a position indicator indicating a position of the valve, for example if the valve is open or closed. This position indicator may break or not function properly. It is desirable to be able to replace the position indicator.

A further problem is that such replacement takes place subsea, possibly at several thousand meters dept. This results in further problems such a high pressures, water current, darkness, presence of water, etc. The position indicator must also comply with regulations and standards in the oil and gas industry.

A further technical problem is that any part of the position indicator and its replacement must function without a possibility to fail, fulfil technical and legal requirements, and be easy to use. It is desirable that any solution is simple, not expensive to produce, and is reliable. It is further a technical problem to avoid cumbersome arrangements that are expensive to manufacture or assemble.

Summary of the Invention

It is an object of the present invention to provide a subsea actuation system with a, at least partly, retrievable position indicator. This object can be achieved by the features as defined by the independent claim. Further enhancements are characterized by the dependent claims. The invention is defined by the claims.

According to one embodiment, a subsea actuation system with a, at least partly, retrievable position indicator 200 is disclosed. A part of the position indicator 200 is at least retrievable. The subsea actuation system being connectable to a subsea structure 10 with a valve 12 with a rising valve stem 14. The rising valve stem 14 comprises a rotation-to-linear mechanism 100 for operating the valve 12. The subsea actuation system comprises an interface 110 for receiving rotational input from a separate retrievable actuator 300. The interface 110 comprises a cylindrical bucket 120 comprising an opening 130 in an axial direction of the cylindrical bucket 120, and a shaft 140 for receiving the rotational input from the retrievable actuator 300, the shaft 140 being connected to the rotation-to-linear mechanism 100. The position indicator 200 is configured for indicating amount of rotational movement of the shaft 140 and hence a position of the valve 12, and at least a part of the position indicator 200 is configured to be positionable at, and retrievable from, the interface 110. A first part 210 of the position indicator 200 is configured for being in an interior 124 of the cylindrical bucket 120, and a second part 220 of the position indicator 200 is configured for being positionable at, and retrievable from, an outer side 152 of the cylindrical bucket 120. The first part 210 being connected to the second part 220 through an opening 122 in the cylindrical bucket 120, the opening 122 being a through opening 122 in the radial direction. The through opening 122 goes through a side 152 of the cylindrical bucket 120, in the radial direction. Further enhancements are characterized by the dependent claims.

At least one of the above embodiments provides one or more solutions to the problems and disadvantages with the background art. Other technical advantages of the present disclosure will be readily apparent to one skilled in the art from the following description and claims. Various embodiments of the present application obtain only a subset of the advantages set forth. No one advantage is critical to the embodiments. Any claimed embodiment may be technically combined with any other claimed embodiment or embodiments.

Brief Description of the Drawings

The accompanying drawings illustrate presently exemplary embodiments of the disclosure and serve to explain, by way of example, the principles of the disclosure.

Fig 1 is a diagrammatic illustration of a subsea actuation system according to an exemplary embodiment of the disclosure;

Fig 2 is a diagrammatic illustration of a subsea actuation system according to an exemplary embodiment of the disclosure; Fig 3 is a diagrammatic illustration of a subsea actuation system according to an exemplary embodiment of the disclosure; and

Fig 4 is a diagrammatic illustration of a subsea actuation system according to an exemplary embodiment of the disclosure.

Detailed Description

Figures 1 to 4 illustrate exemplary embodiments of the subsea actuation system. Fig 1 illustrates an exemplary embodiment of the subsea actuation system, while figures 2 to 4 illustrate different exemplary embodiments of the interface 110 and the position indicator 200.

With reference to Fig 1 there is shown an exemplary embodiment of a subsea actuation system with a, at least partly, retrievable position indicator 200. The subsea actuation system is connectable to a subsea structure 10 with a valve 12 with a rising valve stem 14. The rising valve stem 14 comprises a rotation-to-linear mechanism 100 for operating the valve 12. The subsea actuation system comprises an interface 110 for receiving rotational input from a separate retrievable actuator 300. The subsea structure 10 may be an assembly of valves, such as for example a X-mas tree 10. The valve 12 may be used to regulate the flow of fluid from an oil well and/or may be used to control the flow of fluid emanating from the well or to introduce an additive to the flow of fluid. The valve 12 may control flow in manifolds and other subsea structures. The valve 12 may be operated by the subsea actuation system. The interface 110 of the subsea actuation system is attachable to the subsea structure, for example bolted onto the subsea structure.

The interface 110 comprises a cylindrical bucket 120 and a shaft 140. The cylindrical bucket 120 comprises an opening 130 in an axial direction of the cylindrical bucket 120. The shaft 140 is for receiving the rotational input from the retrievable actuator 300. The shaft 140 is connected to the rotation-to-linear mechanism 100. The opening 130 of the bucket 120 may extend and open in the axial direction to an end 132 of the cylindrical bucket 120 facing away from the subsea structure 10.

The position indicator 200 is configured for indicating an amount of rotational movement of the shaft 140 and hence a position of the valve 12. Thus the position indicated by the position indicator 200 is if the valve 12 is open or closed and how much the valve 12 is open. At least a part of the position indicator 200 is configured to be positionable at, and retrievable from, the interface 110. The part of the position indicator 200 that is outside the bucket 120 may be damaged and may be retrievable, while the part of the position indicator 200 that is inside the bucket 120 may not be damaged and needs not to be retrievable.

A first part 210 of the position indicator 200 is configured for being in an interior 124 of the cylindrical bucket 120, and a second part 220 of the position indicator 200 is configured for being positionable at, and retrievable from, an outer side 152 of the cylindrical bucket 120. The first part 210 is connected to the second part 220 through an opening 122 in the cylindrical bucket 120. The opening 122 being a through opening 122 in the radial direction. The opening 122 goes through the side wall of the bucket 120 so that the first part 210 may connect to the second part 220. It may therefore be sufficient to retrieve and replace only the second part 220, the part of the position indicator 200 that is outside the bucket 120, instead of the whole positon indicator 200.

According to one embodiment, the first part 210 of the position indicator 200 may be configured for being positionable at, and retrievable from, an interior 124 of the cylindrical bucket 120. The first part 210 of the position indicator 200 may be configured for being positionable at, and retrievable from, an outside of the bucket 120. The second part 220 of the position indicator 200 may be configured for being positionable at, and retrievable from, an interior 124 of the cylindrical bucket 120. The second part 220 of the position indicator 200 may be configured for being positionable at, and retrievable from, an outside of the bucket 120. It may be preferred that the second part 220 of the position indicator 200 may be configured for being positionable at, and retrievable from, an outside of the bucket 120, while the first part 210 of the position indicator 200 may remain inside the bucket 120. The first part 210 of the position indicator 200 may be attached to the shaft 140 so that the first part 210 rotates with the shaft 140.

According to one embodiment, as illustrated in Fig 2, the opening 122 may extend in the axial direction of the cylindrical bucket 120. The opening 122 may extend and may open up in the axial direction to an end 132 of the cylindrical bucket facing away from the subsea structure 10. In this way the first part 210 of the position indicator 200 may be retrieved by sliding it in the axial direction of the bucket 120. As illustrated in Fig 1 , the through opening 122 allows the first part 210 of the position indicator 200 to be retrieved by sliding it in the radial direction of the bucket 120. As illustrated in Fig 2, the opening 122 may comprise a lock 126, preferably at the end 132 of the bucket 120. The lock 126 may close the opening 122 at the end 132 of the cylindrical bucket 120. The lock 126 may be, for example, a latch 126. The lock 126 may hold the opening 122 closed and the lock 126 may be opened when the position indicator 200 is retrieved by sliding it in the axial direction of the bucket 120 along the opening 122.

According to one embodiment, the position indicator 220 may be configured to be positionable at, and retrievable from, the interface 110 by the retrievable actuator 300. The position indicator 220 may be configured to be attachble to the interface 110. The position indicator 220 may be configured to be retrievable by the actuator 300. The actuator 300 may have an arrangement, for example a gripper, that can attach and remove the position indicator 220 to and from the interface 110.

As illustrated in the figures, the first part 210 and the second part 220 may be configured to be connectable to each other through the opening 122. This allows the position indicator 220 to be positionable at, and retrievable from, the interface 110 by the retrievable actuator 300. The first part 210 and the second part 220 may be connected by a screw connection or a snap connection or a quick connect coupling. The position indicator 220 and/or the interface 110 may have a guiding arrangement for facilitating such connection.

As illustrated in the figures, the first part 210 of the position indicator 200 may be arranged around the shaft 140. The first part 210 of the position indicator 200 may be arranged around the shaft 140 by a screw connection or a snap connection or a quick connect coupling. The first part 210 of the position indicator 200 may be permanently attached to the shaft 140 with no possibility to remove the first part 210 separately from the shaft 140.

As illustrated in the figures, the first part 210 of the position indicator 200 may comprise a cog wheel. For example, the shaft 140, or the first part 210, may comprise a threaded spindle 212. The shaft 140, or the first part 210, may comprise a saddle nut 214 around the threaded spindle 212. The saddle nut 214 may ride on the threaded spindle 212 and cause a displacement in the axial direction of the second part 220. The second part 220 of the position indicator may be detachably connected to the saddle nut 214. The opening 122 may be elongate to allow such axial displacement, and this displacement may indicate the position of the valve 12, such as for example an open or closed position. Alternatively, such axial displacement may be transferred into another displacement that is easily detectable from a remote operated vehicle operating the separate retrievable actuator 300. Such another displacement may be a linear movement, a rotating movement, of an indicator perpendicular to the axis of the bucket 120 as illustrated in the figures.

As illustrated in Fig 4 the first part 210 may comprise a first spur gear 216 and the second part 220 may comprise a second spur gear 218. The second spur gear 218 may indicate the position of the valve 12 directly, or via a saddle nut riding on a threaded spindle, similar to what has been described above. The first spur gear 216 may be directly attached to the shaft 140.

According to one embodiment and as illustrated by the figures, the shaft 140 and the cylindrical bucket 120 may be concentric. The shaft 140 may extend through the closed bottom of the bucket 120. The shaft 140 is accessible to the separate retrievable actuator 300 through the opening 130 of the bucket 120.

According to one embodiment and as illustrated by the figures, the bucket 120 may be a substantially a right circular hollow cylinder, for example a cylindrical shell, and the rotation-to-linear mechanism 100 may form a bottom 124 of the bucket 120 through which the shaft 140 protrudes. Such an arrangement forms the interface 110 that can receive rotational input from the separate retrievable actuator 300 and at the same time the position indicator 200 can be retrieved by the retrievable actuator 300.

According to one embodiment and as illustrated by the figures, the actuation system may be a valve actuation system, with a rising valve stem, configured to open and close the valve 12. The valve 12 may be a master valve, or a wing vale, of the subsea structure 10. The subsea structure 10 may be a subsea X-mas tree.

According to one embodiment, the rotation-to-linear mechanism 100 and the interface 110 may be bolted to the subsea structure 10. The rotation-to-linear mechanism 100 and the interface 110 may be only retrievable with the subsea structure 10, such as the subsea X-mas tree.

According to one embodiment, the retrievable actuator 300 may be operated by electric power. The retrievable actuator 300 may be operated by a ROV and may comprise batteries and an electric rotational motor. The retrievable actuator 300 may be connectable to the rising valve stem 14.

This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using the adapters and performing the methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.