The present invention relates to an annulus isolation valve assembly associated with the tubing hanger of a subsea well assembly. The annulus isolation valve is adapted to open and close for fluid communication with the tubing annulus of a subsea well, and to constitute a well barrier when closed.
A plurality of annulus isolation valve designs are known. An annulus isolation valve is sometimes referred to as a tubing annulus valve, or an annulus access valve etc. Arranged in the tubing hanger, the annulus isolation valve constitutes a well barrier between the tubing annulus and the environment when there is no subsea Xmas tree installed above the tubing hanger. When the subsea Xmas tree is installed above the tubing hanger, the annulus isolation valve should be open, leaving a fluid path open between the tubing annulus and the Xmas tree.
One design is shown in international application publication WO0173256. Here, a tubing hanger has an annulus isolation valve in the form of a gate valve. The gate is adapted to reciprocate in the vertical direction, between an open and closed valve position. A fluid path extends crosswise to the reciprocating direction of the gate, and is opened and closed by moving the gate.
A different design is shown in patent publication U.S. Pat. No. 6,840,323. Here, a fixed valve seat is arranged inside the bore of a valve sleeve. By moving the valve sleeve, the fixed valve seat is moved, with respect to the valve sleeve, from a large diameter portion to a small diameter portion. When in the small diameter portion, the fixed valve seat seals against the valve sleeve, thereby closing the fluid path. Notably, fluid flows through the valve sleeve bore. Moreover, the fluid flows directly in contact with the seals of the valve seat and the opposite sealing surface of the sleeve bore.
Yet another design is disclosed in US patent publication U.S. Pat. No. 5,706,893. This valve resembles a gate valve, where the gate protrudes horizontally out from a centrally arranged and rotating sleeve. The gate has an aperture which is aligned with a vertical flow path when in the open position, and which is removed from the vertical flow path when in the closed position.
WO2010022170 describes a design where an axially moving valve sleeve is arranged in parallel with a flow bore. The valve sleeve is hollow and exhibits an upper and a lower aperture. In a first (open) axial position, the upper aperture is aligned with a flow port communicating with the flow bore, while the lower aperture communicates with the tubing annulus. In a second (closed) axial position, the both the upper and the lower apertures are aligned with a cylindrical wall, within which the valve sleeve is supported.
The invention
According to a first aspect of the present invention, there is provided an annulus isolation valve assembly being part of a tubing hanger assembly, the annulus isolation valve assembly (AIV assembly) comprising a valve bore with a fluid mouth. The AIV assembly further comprises a sliding sleeve which is arranged in the valve bore and which has an axially extending sleeve bore. The sliding sleeve comprises a radially facing sleeve port. A hydraulic piston is functionally connected to the sliding sleeve. According to the first aspect of the present invention, the sliding sleeve comprises an axially facing fluid port which is in fluid communication with the radially facing sleeve port.
The annulus isolation valve assembly being part of a tubing hanger assembly, means that it is either an integrated part of the tubing hanger, such as integrated within the tubing hanger main body, or that it may be attached to the tubing hanger main body, such as below it.
The annulus isolation valve assembly will be in an open mode or position when the sleeve port is aligned with or at least has fluid communication with the fluid mouth. Thus, the sliding sleeve can be slid into and out from such an open mode, thereby opening and closing the annulus isolation valve.
The fluid path through the valve assembly, when in the open mode, extends through the sliding sleeve. In particular, the fluid path through the sliding sleeve extends between an axially facing port and a radially facing port (the sleeve port). As a consequence, a pressure in the fluid will exert a force onto the sliding sleeve. Thus, the operator will be able to actuate movement of the sliding sleeve by controlling the pressure in the fluid entering the axially facing port.
Advantageously, the AIV assembly further comprises a primary hydraulic opening chamber and a primary hydraulic closing chamber.
Preferably, the sleeve port is arranged, in the axial direction, between the axially facing fluid port and a closed sleeve end portion. A secondary hydraulic closing chamber is then confined by at least the closed sleeve end portion, a first end of the valve bore, and the valve bore.
That is, the secondary hydraulic closing chamber can advantageously be axially confined by the closed sleeve end portion and the first and of the valve bore, and radially confined by the walls of the valve bore.
One can also imagine embodiments where the primary and secondary hydraulic closing chambers have switched places. In such embodiments, the chamber between the closed sleeve end portion and the first end of the valve bore would be the primary hydraulic closing chamber, which would be used by the operator during normal use.
In some embodiments, the AIV assembly may be arranged with a vertical or inclined orientation. Then, the first end of the valve bore is a lower valve bore end. Moreover, a fixed insertion sleeve extends into the sleeve bore and defines a wall portion of the primary hydraulic opening chamber. The hydraulic piston is a collar protruding radially out from the sliding sleeve.
In a particular embodiment, a piston compensator is in fluid communication with the primary hydraulic closing chamber or the secondary hydraulic closing chamber. Moreover, the piston compensator comprises a position indication means.
With such an embodiment, the operator is able to establish the position of the sliding sleeve by inspection of the position indication means.
In one embodiment, the first end of the valve bore is in a valve body which is attached to a lower portion of a main body of the tubing hanger assembly. The valve body may preferably be attached to the main body of the tubing hanger by means of bolts, thus being easily detachable.
According to a second aspect of the present invention, there is provided a method of shifting an annulus isolation valve assembly of a tubing hanger assembly from a closed mode to an open mode, wherein the tubing hanger assembly is installed in a subsea wellhead assembly, below a subsea Xmas tree. The annulus isolation valve assembly constitutes a closure between a tubing annulus and an annulus bore of the subsea Xmas tree, wherein the method comprises the following steps
When installed in the subsea wellhead assembly, the tubing hanger assembly is typically installed inside a wellhead or in a tubing head spool between the wellhead and the subsea Xmas tree.
Step a) may further comprise bleeding off a secondary hydraulic closing chamber.
According to a third aspect of the present invention, there is provided a method of determining or verifying an open mode of an annulus isolation valve assembly of a tubing hanger assembly installed in a wellhead assembly below a subsea Xmas tree. The annulus isolation valve assembly has a hydraulic closing chamber and a hydraulic opening chamber. The method comprises the following steps:
To perform this method, a pressure gauge may be arranged in a position to measure the fluid pressure of the hydraulic closing chamber during step c. If the measured pressure changes above a threshold value, it is an indication of the sliding sleeve not having landed in the open position. If the pressure change is below the threshold value, it is an indication of a non-moving sliding sleeve, hence indicating that the repeated pressurizing of the hydraulic opening chamber does not affect the sliding sleeve. This is further an indication of the sliding sleeve being in the open position.
While the present invention has been described in general terms above, an example of embodiment is presented in the following. The embodiment is discussed with reference to the drawings, in which
Arranged in the tubing hanger 100 is a production bore 101. Moreover, adjacent the production bore 101, in the tubing hanger main body, there is an annulus access bore 103. The annulus access bore 103 provides fluid communication between the production tubing annulus below the tubing hanger 100 and the Xmas tree above the tubing hanger.
When the Xmas tree is landed above the tubing hanger 100, a stinger (not shown) extends downwards from the Xmas tree and into a stinger interface 12, arranged in the upper portion of the tubing hanger 100.
When the Xmas tree is not installed above the tubing hanger 100, the access to the tubing annulus must be closed. Thus, an annulus isolation valve (AIV) assembly 1 is arranged within the annulus access bore 103.
When moving between the open and closed positions, respectively, the sliding sleeve 11 alters between an open and closed fluid communication to a lower valve channel 10. The lower valve channel 10 constitute at least a portion of a fluid path leading to the tubing annulus.
While
It is now referred to the enlarged cross section views of
Within the tubing hanger main body 3 a valve bore 5 is arranged. The valve bore 5 has a closed, lower end 7. Some axial distance above the lower end 7, the valve bore 5 has two fluid mouths 9. The fluid mouths 9 are in fluid connection with the annulus, via a lower valve channel 10. In the shown embodiment, the AIV assembly 1 comprises two fluid mouths 9 which are aligned with respective sleeve ports 17 of the sliding sleeve 11. In other embodiments, there may be only one pair of a fluid mouth 9 and a port 17, or even more than two.
Inside the valve bore 5, the sliding sleeve 11 is arranged. The sliding sleeve 11 is adapted to reciprocate in an axial (vertical) direction within the valve bore 5. The sliding sleeve 11 has a sleeve bore 13 and a lower sleeve end 15. Some distance above the lower sleeve end 15, the through sleeve port 17 is arranged in the sleeve bore 13. In
In the shown embodiment, below the sleeve ports 17, the sliding sleeve 11 has a lower sleeve portion 19 which is massive (having no bores). Thus, the lower sleeve portion 19 is a closed sleeve end portion. Above the sleeve ports 17, the sleeve bore 13 extends upwards. At an upper portion of the sleeve bore 13 there is arranged a hydraulic piston 21 which protrudes radially outwards from a sleeve bore wall 23. The hydraulic piston 21 can move between an upper and lower position, along a hydraulic chamber bore 25, which is a widened portion of the valve bore 5.
Fixed to the main body 3 of the tubing hanger 100, there is a fixed insertion sleeve 27, which extends a distance into the sleeve bore 13. The fixed insertion sleeve 27 has an inner bore which is open in both axial ends. Moreover, it extends axially in parallel to the hydraulic chamber bore 25. The upper part of the sleeve bore 13 constitutes an axially facing fluid port 47. When in the open mode, annulus fluid may flow through the AIV assembly through the axially facing fluid port 47. As shown in
It is now referred to
Referring again to
A primary hydraulic closing channel 35 leads to the primary hydraulic closing chamber 33, through the main body 3 of the tubing hanger 100. Correspondingly, primary hydraulic opening channel 39 leads to the primary hydraulic opening chamber 29. Thus, by applying pressurized hydraulic fluid to the respective primary hydraulic chambers 29, 33, the operator is able to actuate the AIV assembly 1 between the open and closed positions (
The hydraulic fluid can be supplied in various manners, such as with an ROV (remotely operated vehicle), an SCM (subsea control module) or with other interfaces.
Typically, one wants the AIV assembly 1 to be in the open position or mode, when a vertical Xmas tree (not shown) is arranged above the tubing hanger 100. Moreover, when the vertical Xmas tree is removed, one wants the AIV assembly 1 to remain closed, constituting a well barrier.
Thus, the ability of closing the AIV assembly 1 is crucial. Therefore, a redundant, secondary closing means is arranged. Between the lower end 7 of the valve bore 5, and the lower sleeve end 15, a secondary hydraulic closing chamber 43 is arranged. A secondary hydraulic closing channel 45 provides fluid communication between a hydraulic fluid source and the secondary hydraulic closing chamber 43. Thus, if for some reason, the operator is unable to close the AIV assembly 1 by using the primary means, namely by applying hydraulic pressure to the primary hydraulic closing chamber 33, he may actuate the sliding sleeve 11 by applying hydraulic pressure inside the secondary hydraulic closing chamber 43.
Correspondingly, a redundant or secondary means of opening the AIV assembly 1 exists, in case the operator, for some reason, is unable to open the AIV assembly 1 by applying hydraulic pressure inside the primary hydraulic opening chamber 29. As a secondary means for actuating the sliding sleeve 11 in the axially downward direction, he may bleed off the primary hydraulic closing chamber 33 and the secondary hydraulic closing chamber 43. Then he may apply fluid pressure inside the sleeve bore 13. Since the sleeve ports 17 face in a radial direction, while the axially facing fluid port 47 faces in an axial direction, a fluid pressure within the sleeve bore 13 will exert a downwardly directed force onto the sliding sleeve 11. Hence, the sliding sleeve 11 may move down into the open position (
In the embodiment discussed above with reference to
The perspective view of
The function of the AIV assembly 1 shown in this second embodiment corresponds to the function of the embodiment discussed above with reference to
Corresponding to the first discussed embodiment, this embodiment of the AIV valve 1 also has a primary hydraulic closing chamber 33, a primary hydraulic opening chamber 29, as well as a secondary hydraulic closing chamber 43. Moreover, by bleeding off the hydraulic chambers, the operator may use pressure within the sleeve bore 13 to move the sliding sleeve downwards into the open position.
A pin 51 is fixed at the lower end 7 of the valve bore 5, and extends upwards into a pin-receiving bore 53 in the sliding sleeve 11. As appears from the cross section view of
In the embodiment discussed above, however, with reference to
In both of the embodiments described above, the sleeve ports 17 and the fluid mouths 9 are arranged at the respective ends of inclined fluid paths. One may, however, also have the sleeve ports 17 and the fluid mouths 9 designed as being the ends of radially extending fluid paths.
Still referring to
Correspondingly, hydraulic channel valves may advantageously be arranged in the primary hydraulic closing channel 35 and the primary hydraulic opening channel 39. Such valves are typically check valves which are adapted to retain hydraulic fluid within their respective hydraulic chambers (e.g. chambers 43, 33, 29). Moreover, when a subsea Xmas tree lands above the tubing hanger 100, the check valves will open, rendering functions in the Xmas tree in control of the hydraulic fluid.
Number | Date | Country | Kind |
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20150862 | Jul 2015 | NO | national |
Filing Document | Filing Date | Country | Kind |
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PCT/NO2016/050141 | 6/27/2016 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2017/007332 | 1/12/2017 | WO | A |
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Number | Date | Country |
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021887 | Sep 2015 | EA |
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Entry |
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Number | Date | Country | |
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20180187513 A1 | Jul 2018 | US |