WO2012095485A2

WO2012095485A2 - Subsea tree jumper assembly

Info

Publication number: WO2012095485A2
Application number: PCT/EP2012/050426
Authority: WO
Inventors: Sergio SABEDOTTI; Robert STUBBEMAN
Original assignee: Aker Subsea As
Priority date: 2011-01-12
Filing date: 2012-01-12
Publication date: 2012-07-19
Also published as: WO2012095485A3; NO20110048A1

Abstract

Subsea Xmas tree assembly including a Xmas tree (5), a tree frame (3), and a plurality of actuators (13) with subsea mateable connections. The actuators (13) are connected to a control module (11) through a communication assembly. The communication assembly comprises a splitter device (105) and a number of first jumpers (103) connected between the subsea mateable connections of the actuators (13) and the splitter device (105). Furthermore, the communication assembly comprises a lesser number of second jumpers (101) connected between the control module (11) and the splitter device (105).

Description

Subsea tree jumper assembly

The present invention relates to subsea Xmas trees and in particular jumpers providing communication between a control module and various tree actuators. Background

It is common to operate subsea xmas tree actuators remotely, for instance from a floating installation. Such xmas trees may include various valve actuators for opening and closing fluid communication. Due to possible failure of the

communication with the actuators or the desire to operate a valve without communicating a signal through the field communication network, it is common to provide the actuators with ROV interfaces, thus allowing the operator to operate the relevant actuators with an ROV (remotely operated vehicle). Trees may include locking devices for locking or unlocking subsea elements to the tree itself or locking the tree to the wellhead. In addition, the operator may monitor parameters such as temperature and pressure in the well and in the tree by monitoring gauges.

It is common to remotely operate the actuators by means of electricity or hydraulic fluid provided from the subsea control module arranged to the Xmas tree assembly.

The control module is connected to the operator through communication lines and contains electric and/or hydraulic means to operate the actuators. The control module is connected to the various actuators through jumpers.

The actuators are typically arranged in a cluster on one side of the tree frame. Furthermore, it is common to protect the actuators with an actuator cover. The actuator cover exhibits a plurality of apertures that make it possible for an ROV to engage and operate the actuators through the apertures. In addition, the actuator cover has markings for the apertures, informing the ROV-operator which aperture leads to which actuator.

Because of the size of the subsea control module, it is arranged on an opposite or adjacent side of the tree frame, with respect to the cluster of actuators and the actuator cover. Thus, the jumpers leading from the control module to the actuators must be routed between various tree assembly components. This routing is performed when assembling the tree assembly before it is lowered down to the well. It is advantageous not to have the jumpers routed laterally external the tree frame, since they would then be exposed to damage for instance by collision with an ROV or other subsea tools.

If a jumper needs to be replaced, the Xmas tree assembly is normally retrieved to the surface. This is a time-consuming process which is desirable to avoid. Thus it is an object of the present invention to provide a subsea tree assembly which is adapted to facilitate replacement of a jumper at a subsea location by means of an ROV.

The invention

According to the invention, there is provided a subsea Xmas tree assembly including a Xmas tree, a tree frame, and a plurality of actuators with subsea mateable connections, wherein the actuators are connected to a control module through a communication assembly. The communication assembly comprises a splitter device, a number of first jumpers connected between the subsea mateable connections of the actuators and the splitter device, and a lesser number of second jumpers connected between the control module and the splitter device. Said lesser number of second jumpers may be one.

Thus, with such a subsea Xmas tree, according to the present invention, the operator is provided with the opportunity to replace a malfunctioning

communication path between an actuator and the control module. If one of the first jumpers is malfunctioning, the operator will replace this one. When doing so, he only needs to route the new jumper along the relatively short distance between the subsea mateable connection of the respective actuator and the splitter device. This he may do by means of a remotely operated vehicle (ROV). If the second jumper, or one of the second jumpers, is malfunctioning, he may replace this jumper with a replacing second jumper. This he will route between the splitter device and the control module. As will appear from the example description of a preferred embodiment below, the second jumper may advantageously be routed along an upper part of the tree frame. This may imply that the main horizontal portion of the routing path of jumpers is adapted to be exposed to the surroundings in the upwards direction. This feature provides the operator with access to the jumpers by means of an ROV from above.

Preferably, the feature of having the jumpers routed mainly along an upper face of the tree frame will imply that most of the routing portion of the jumpers that is in the lateral direction (i.e. the horizontal component) is performed along the upper face of the tree frame or tree assembly, and that the jumper or jumpers in this routing portion are not covered by any assembly component, except perhaps by a possible protective structure. Thus, preferably the operator will be able to lay down a jumper from above into its intended routing path, in the said routing portion, without having to remove a tree assembly component (except from the possible protective structure, such as a hatch) or having to thread the jumper through openings or beneath tree assembly components. In the subsea position, the operator will be able to perform the routing by means of an ROV. Preferably, the tree frame exhibits a substantially rectangular shape with four lateral sides and that the actuators and the control module are arranged on an opposite or adjacent side of the tree frame. Thus, at least some of, or the majority, of the actuators are arranged at another side of the tree frame than the control module. This makes it necessary to route jumpers a certain distance between the actuators and the control module.

In a preferred embodiment of the present invention, the communication assembly comprises a redundant number of second jumpers. By having a redundant number of second jumpers, the replacement of a malfunctioning second jumper may be avoided. This may save valuable time for the operator.

As briefly mentioned above, the second jumper(s) may be routed in a path protected by a removable protection structure constituting a portion of the upper face of the tree frame. Such a protection structure may be in the form of a moveable hatch, or may be a fixed structure of the tree assembly.

In a preferred embodiment the second jumper(s) are routed in a guiding arrangement, such as a guiding duct.

In yet another possible embodiment of the present invention, the splitter device comprises a logic unit adapted to receive instructions in the form of electronic signals from an operator. Furthermore, the second jumper(s) comprise a number of electrical communication lines which is less than the number of first jumpers. In this embodiment, the logic unit is adapted to choose which actuator to operate on the basis of said instructions. This embodiment reduces the required amount of conductors in the second jumper(s). That is, instead of communicating with each actuator through a passive splitter device, the operator communicates with an active splitter device that forwards the instructions to the correct actuator by means of a logic unit.

Example of embodiment

While the general features of the invention has been described in the above, a more detailed non-limiting example of embodiment will be described in the following with reference to the drawings, in which

Fig. 1 is a perspective view of a tree assembly according to the invention,

including a Xmas tree spool and a tree frame;

Fig. 2 is a perspective view of the tree assembly in Fig. 1 , shown from another angle;

Fig. 3 is a perspective view of the tree assembly in Fig. 1 , shown from a third angle;

Fig. 4 is a perspective view of the tree assembly in Fig. 1 , shown from a fourth angle and with a top part of the assembly removed;

Fig. 5 is a top view of the tree assembly in Fig. 1 ;

Fig. 6 is an enlarged perspective section view of the view in Fig. 3; and

Fig. 7 is a perspective view of a jumper guiding arrangement. Fig. 1 shows a subsea tree assembly 1 with a tree frame 3 and a Xmas tree 5 arranged within it. The Xmas tree 5 has a tree spool 7 extending upwards from the tree frame 3. The tree frame 3 has a substantially rectangular shape, with a corner post 9 typically located at each of the four corners.

For the purpose of describing the shown example of embodiment, the tree assembly 1 is defined to have a front face 3a, a back face 3b, and two side faces 3c. In addition, it has a top face 3d. A control module 1 1 is arranged at the back face 3b side of the tree 5. The control module 1 1 is connected to a topside location, such as to a floating installation (not shown). The control module 1 1 shown in this embodiment has four wet-mate connections 1 1 a that are adapted to be connected to jumpers 101 by means of an ROV (remotely operated vehicle). The jumpers 101 contain electrical and/or hydraulic conductors for communication with a plurality of tree actuators 13 arranged on the opposite side of the tree 5, namely at the front face 3a of the tree assembly 1 .

The tree actuators 13 can thus be remotely controlled by the operator through the control module 1 1 and connected jumpers 101 . The actuators 13, shown on the diagrams, are tree valve actuators for controlling various fluid passages, but the jumpers 101 could also be connected to tree pressure and temperature sensors, or throttle valve systems, splitter boxes, or other equipment with which power and/or signal communication is necessary.

As slightly indicated in Fig. 1 , two jumpers 101 are routed from the back face 3b towards the front face 3a along an upper part of the tree assembly 1 . In the upper part or the top face 3d of the tree frame 3, there is arranged protective structure in the form of a protection hatch 15. The protection hatch 15 is arranged above the path of the jumpers 101 towards the actuators 13. As illustrated in Fig. 2, the protection hatch 15 is connected to the tree frame 3 with hinges, so that an ROV is able to move it between an opened and closed position. When in the closed position, the protection hatch 15 is flush with an adjacent top plate, so as to constitute a substantially plane top face of the tree frame 3. Referring now also to Fig. 2 and Fig. 3, the plurality of actuators 13 is arranged at the front face 3a of the tree assembly 1 . In front of the actuators 13 there is arranged an upper ROV panel 17a and a lower ROV panel 17b. The upper ROV panel 17a is connected to the tree frame 3 by hinges 19. Thus, the upper ROV panel 17a can be moved between an open and closed position by means of an ROV. In addition the ROV panels 17a, 17b exhibit apertures 21 through which an ROV can gain access to an actuator 13. Thus, in case of malfunction of the communication line between an operator and a tree actuator 13, the operator can employ an ROV to manipulate the actuator 13, through said apertures 21 .

In case of a malfunctioning actuator 13, it can be replaced by a replacement actuator by using an ROV when the ROV panel 17a is in the open position. Thus, the operator does not need to retrieve the entire tree assembly 1 to the surface in order to replace the actuator 13.

To prevent the ROV panel 17a from moving unintentionally, for instance due to water current, the tree assembly advantageously comprises a security locking means (not shown) that retains the panel in its closed position. Such a locking means can for instance be a simple hook on the tree frame 3 which the operator can flip into and out of a loop in the ROV panel 17a to lock and unlock, by means of the ROV. It can also, for instance, be a retaining clip device that will retain the ROV panel in the closed or a predetermined open position until a predetermined force is exerted onto the panel. Another embodiment includes arranging a motor to the panel, making the operator able to remotely open or close the panel and maintaining it in the desired position by means of the motor.

The actuators 13 are provided with wet-mateable connections 13a that are connected to jumpers 103. The jumpers 103 constitute part of the communication line between the operator and the actuators 13. It is known in the art to connect jumpers directly between an actuator 13 and the control module 1 1 . However, in this embodiment, a plurality of first jumpers 103 are connected between the actuators 13 and a splitter device 105, while a pair of second jumpers 101 are connected between the splitter device 105 and the control module 1 1 . This will now be explained in further detail.

The splitter device 105 is arranged close to the actuators 13, at the front face 3a of the tree assembly 1 . This is illustrated in Fig. 3, showing the tree assembly 1 with the protection hatch 15 and the adjacent top plate removed for the purpose of illustration. The splitter device 105 has a plurality of first wet mate connections 105a which are connected to the first jumpers 103 connected to the actuators 13. In addition, as illustrated in the top view of Fig. 5, it has second wet mate connections 105b connected to the second jumpers 101 , which are connected to the control module 1 1 . Thus, the splitter device 105 connects a number of the first jumpers 103 into a lesser number of second jumpers 101 . Advantageously, only one second jumper 101 will suffice in order to establish communication between the control module 1 1 and the connected actuators 13. However, in case of malfunction of the second jumper 101 , a redundant second jumper 101 is arranged in parallel with the other, so that a replacement is avoided in case one of the two malfunctions.

It will now be apparent for the person skilled in the art that the described tree assembly 1 is particularly well adapted for replacing a jumper 101 , 103 and/or an actuator 13 by means of an ROV. In stead of, as according to the prior art, having to replace a jumper running from one actuator to a distantly arranged control module by means of the ROV, one can now replace either a short first jumper 103 arranged at the front face 3a of the assembly 1 , or the second jumper 101 arranged at the top face 3d of the assembly 1. This makes it unnecessary to route a jumper according to the prior art along the exterior of the tree frame 3 or to retrieve the entire assembly to the surface for jumper replacement.

In addition, with the possibility to open the ROV panel 17a with the ROV, the operator is also able to replace a malfunctioning actuator 13 at the subsea location. In this embodiment the lower ROV panel 17b is bolted to the tree assembly 1 , and has small valves bolted to it. One could however also imagine an embodiment where the valves where arranged behind the lower panel 17b, and the panel being movable. Fig. 6 shows a part of the view in Fig. 3 in closer detail.

In the top part of the tree assembly 1 , there is advantageously arranged a jumper guiding arrangement 201 (not shown in Fig. 6). This principle is shown separately in Fig. 7, showing a part of the splitter device 105, the control module 1 1 , and two second jumpers 101 arranged in a guiding duct 201 . Thus, the second jumper or jumpers 101 will be easy to route by means of an ROV, between the splitter device 105 and the control module 1 1 . In addition the jumpers will be well protected by the movable protection hatch 15, shown in Fig. 1 and Fig. 2.

In stead of the guiding duct 201 , as shown in Fig. 7, one could also imagine other types of jumper guiding arrangements 201 . For instance a row of U-shaped bows can be arranged in the upper part of the tree frame 3.

As an alternative embodiment of the communication assembly between the control module 1 1 and the actuators 13, a second jumper 101 ' is guided from the control module 1 1 to a logic splitter device 105'. In this alternative embodiment, the second jumper 101 ' does not comprise the plurality of communication lines originating from the actuators 13 and combined in the splitter device 105, as described above. In stead, it only has one, two, three, or a few communication lines with the logic splitter device 105'. The operator thus communicates with a logic unit within the logic splitter device 105', and the splitter device is adapted to transmit or receive the desired electrical signal to or from an actuator 13. Thus, by arranging a logic unit, such as a microcontroller, within the splitter device 105', the second jumper(s) 101 ' can be reduced to a single jumper or a jumper with fewer lines than the second jumper 101 according to the embodiment described above. An advantage of this is that the wet mate connection comprises fewer contacts.

Claims

1. Subsea Xmas tree assembly including a Xmas tree (5), a tree frame (3), and a plurality of actuators (13) with subsea mateable connections, wherein the actuators (13) are connected to a control module (1 1 ) through a communication assembly, characterized in that the communication assembly comprises

- a splitter device (105);

- a number of first jumpers (103) connected between the subsea mateable

connections of the actuators (13) and the splitter device (105); and

- a lesser number of second jumpers (101 ) connected between the control module (1 1 ) and the splitter device (105).

2. Subsea Xmas tree assembly according to claim 1 , characterized in that the tree frame (3) exhibits a substantially rectangular shape with four lateral sides and that the actuators (13) and the control module (1 1 ) are arranged on an opposite or adjacent side of the tree frame (3).

3. Subsea Xmas tree assembly according to claim 1 or 2, characterized in that the communication assembly comprises a redundant number of second jumpers (101 ).

4. Subsea Xmas tree assembly according to any one of the preceding claims, characterized in that the splitter device (105) and the second jumper(s) (101 ) are arranged in an upper part of the tree frame (3).

5. Subsea Xmas tree assembly according to claim 4, characterized in that the second jumper(s) () are routed in a path protected by a removable protection structure constituting a portion of the upper face (3d) of the tree frame (3).

6. Subsea Xmas tree assembly according to claim 4 or 5, characterized in that the second jumper(s) () are routed in a guiding arrangement (201 ), such as a guiding duct.

7. Subsea Xmas tree assembly according to one of the preceding claims,

characterized in that - the splitter device (105) comprises a logic unit adapted to receive instructions in the form of electronic signals from an operator;

- the second jumper(s) (101 ) comprise a number of electrical communication lines which is less than the number of first jumpers (103);

- wherein the logic unit is adapted to choose which actuator (13) to operate on the basis of said instructions.