ANNULAR RELIEF VALVE
A pressure relief valve assembly may be coupled to one or more casings and/or tubular members to control fluid communication therebetween. In one embodiment, the valve assembly includes a tubular body having a port for fluid communication between an exterior of the tubular body and an interior of the tubular body; a chamber formed in a wall of the tubular body, the chamber in fluid communication with the port; a closure member disposed in the chamber and configured to control fluid communication through the port in response to a pressure differential; and a retaining member coupled to the closure member for retaining the closure member in an open position.
This application claims benefit of U.S. Provisional Patent Application Ser. No. 61/880,690, filed Sep. 20, 2013, which application is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION1. Field of the Invention
Embodiments of the invention generally relate to a pressure relief valve assembly for a casing.
2. Description of the Related Art
Traditional well construction, such as the drilling of an oil or gas well, includes a wellbore or borehole being drilled through a series of formations. Each formation, through which the well passes, must be sealed so as to avoid an undesirable passage of formation fluids, gases or materials out of the formation and into the borehole. Conventional well architecture includes cementing casings in the borehole to isolate or seal each formation. The casings prevent the collapse of the borehole wall and prevent the undesired inflow of fluids from the formation into the borehole.
In standard practice, each succeeding casing placed in the wellbore has an outside diameter significantly reduced in size when compared to the casing previously installed. The borehole is drilled in intervals whereby a casing, which is to be installed in a lower borehole interval, is lowered through a previously installed casing of an upper borehole interval and then cemented in the borehole. The purpose of the cement around the casing is to fix the casing in the well and to seal the borehole around the casing in order to prevent vertical flow of fluid alongside the casing towards other formation layers or even to the earth's surface.
If the cement seal is breached, due to high pressure in the formations and/or poor bonding in the cement for example, fluids (liquid or gas) may begin to migrate up the borehole. The fluids may flow into the annuli between previously installed casings and cause undesirable pressure differentials across the casings. The fluid gas may also flow into the annuli between the casings and other drilling or production tubular members that are disposed in the borehole. Some of the casings and other tubulars, such as the larger diameter casings, may not be rated to handle the unexpected pressure increases, which can result in the collapse or burst of a casing or tubular.
Therefore, there is a need for apparatus and methods to prevent wellbore casing or tubular failure due to unexpected downhole pressure changes.
SUMMARY OF THE INVENTIONA pressure relief valve assembly may be coupled to one or more casings and/or tubular members to control fluid communication therebetween. The valve assembly is a one-way valve assembly that relieves pressure within an annulus formed between adjacent casings and/or tubular members to prevent burst or collapse of the casings and/or tubular members. In one embodiment, the valve assembly includes a tubular body having a port for fluid communication between an exterior of the valve assembly and an interior of the valve assembly; a chamber formed in a wall of the tubular body, the chamber in fluid communication with the port; a closure member disposed in the chamber and configured to control fluid communication through the port in response to a pressure differential; and a retaining member coupled to the closure member for retaining the closure member in an open position.
In another embodiment, the valve assembly includes a biasing member for biasing the closure member in a closed position. The valve assembly may include a plug disposed on an end opposite the closure member. In one aspect, the activation force of the closure member is adjustable. The activation force may be adjusted by changing a location of the plug. In another embodiment, the activation force may be adjusted by changing a length of the piston.
In another embodiment, a method of operating a valve assembly includes coupling a valve assembly to a casing and the valve assembly having a tubular body having a port for fluid communication between an exterior of the valve assembly and an interior of the valve assembly; a chamber formed in a wall of the tubular body, the chamber in fluid communication with the port; a closure member disposed in the chamber and configured to control fluid communication through the port; and a retaining member coupled to the closure member for retaining the closure member in an open position. The method further includes opening the valve assembly in response to a predetermined pressure differential between the exterior and the interior of the valve assembly, and retaining the closure member in the open position.
So that the manner in which the above recited features of the invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
In one embodiment, a pressure relief valve assembly may be coupled to one or more casings and/or tubular members to control fluid communication there between. The valve assembly is a one-way valve assembly that relieves pressure within an annulus formed between adjacent casings and/or tubular members to prevent burst or collapse of the casings and/or tubular members. The valve assembly may be resettable downhole.
The wellbore 5 may intersect a high pressure zone 50 within the formation 80. Fluids within the high pressure zone 50 are sealed from the annulus A and B by the sealing material 25 that is disposed between the casing 20 and the wellbore wall. In the event that the sealing material 25 is breached or otherwise compromised, pressurized fluids may migrate upward into the annulus A and cause an unexpected pressure increase. The pressure rise may form a pressure differential across the casings 10, 20 that, if unchecked, may result in leakage through or burst of casing 10, and/or leakage through or collapse of casing 20. One or more valve assemblies 300, 700 are provided to relieve the pressure in the annulus A prior to failure of one or both of the casings 10, 20.
The tubular body 705 includes a chamber 713 for housing a closure member 720. The closure member 720 is used to operate the relief port 715. An exemplary closure member is a piston 720. In one embodiment, the piston 720 includes a first portion 721 having a smaller diameter than a second portion 722. A seal 731, 732 is disposed around each of the first and second portions 721, 722 of the piston 720 for sealing engagement with the chamber 713. An exemplary seal is an o-ring. The piston 720 is movably disposed in the chamber 713 to operate the valve. As shown, the piston 720 is biased in the closed position using a biasing member 735. Exemplary biasing members 735 include a coil spring or a wave spring. The biasing member 735 may be configured to retract in response to a force near or below the burst or collapse rating of the casing 20. One or more plugs may optionally be used to enclose the chamber 713. In the embodiment as shown, three plugs 727, 728 are used to close off openings in the tubular body 705 formed during manufacture of the valve assembly 700. The plugs 727, 728 may optionally include a seal 726, a retaining ring 729, or both.
In one embodiment, the chamber 713 can fluidly communicate with the relief port 715 and a chamber port 719 of the body 705. The relief port 715 allows fluid communication between the bore 701 and the portion 741 of the chamber 713 defined by the first seal 731. The chamber port 719 allows fluid communication between the bore 701 and the portion 742 of the chamber 713 defined by the second seal 732. An inflow port 718 and an actuation port 745 allow fluid communication between the exterior of the tubular body 705 and the portion 743 of the chamber 713 between the first seal 731 and the second seal 732. In this respect, these ports 718, 745 are blocked from fluid communication with the bore by the closure member 720 when the valve assembly 700 is in the closed position. The inflow port 718 and the actuation port 745 are positioned such that in the open position, the inflow port 718 is allowed to communicate with the relief port 715, and the actuation port 745 remains blocked from communication with the bore 701.
Referring back to
When the pressure in annulus A is sufficient to overcome the biasing force and the force from the annulus B pressure, the piston 720 is retracted to open the inflow port 718 and place the inflow port 718 in fluid communication with the relief port 715.
When the force on piston 720 due to pressure in the annulus A decreases below the sum of the force on piston 720 due to pressure in annulus B plus the biasing force of the biasing member 735, the biasing member 735 returns the piston 720 to the closed position, thereby closing off fluid communication through the relief port 715. In this manner, the valve assembly 700 is operable as a one-way valve in that it will permit fluid flow into the bore 701 of the valve assembly 700 but will prevent fluid flow out of the bore 701 via the relief port 715. The valve assembly 700 is automatically resettable downhole and may be operated multiple times in response to any pressure fluctuations within the wellbore 5. As stated above, any of the casings 10, 20, 30 and/or the tubular members 40, 45 may each be provided with one or more valve assemblies 700 to allow fluid flow from a surrounding casing or tubular member to an inner casing or tubular member, while preventing fluid flow in the opposite direction.
Referring to
The tubular body 305 includes a chamber 313 for housing a closure member 320. The chamber 313 is in fluid communication with the bore 301 via the relief port 315 and a chamber port 319. Also, the chamber 313 is in selective fluid communication with the exterior of the tubular body 305 via an inflow port 318. In one embodiment, the chamber 313 may include a shoulder 344 disposed between a smaller diameter section 311 of the chamber 313 and a larger diameter section 312 of the chamber 313.
The closure member 320 is used to selectively control fluid communication between the relief port 315 and the inflow port 318. An exemplary closure member is a piston 320. In one embodiment, as shown in
The retaining member 323 is coupled to the head portion 322 and is configured to retain the piston 320 in the open position. In one embodiment, the retaining member is a collet 323. The collet 323 may extend along the stem of the body portion 321 and may flex radially inwardly and outwardly. As shown in
Referring back to
A plug 328 is provided to engage the other end of the biasing member 335 and to enclose the chamber 313. The plug 328 is disposed in an opening 375 of the tubular body 305 that leads to the chamber 313. As shown, the opening 375 has a larger diameter than the chamber 313, thereby forming a shoulder 376 at the interface. In another embodiment, the opening 375 may have the same or different diameter than the chamber 313. The plug 328 may optionally include a seal 326 to prevent communication through the opening 375. The plug 328 may include a recess for receiving the seal 326. The plug 328 may separate into a front section and a body section at the recess to facilitate installation of the seal 326. The two sections may be connected using threads, interference fit, and other suitable connection mechanisms. The front section may include an outer diameter of sufficient size to engage the shoulder 376. The plug 328 may optionally include a retrieval receptacle for receiving a retrieval tool to facilitate removal of the plug 328 from the opening 375. In another embodiment, the body section may include threads for attachment to the opening 375. In addition to threads, it is contemplated that the plug 328 may attach to the opening 375 using an interference fit, a locking mechanism such as a pin or screw, or any suitable attachment mechanism.
In one embodiment, the valve assembly 300 includes an adjustable activation pressure feature. Referring again to
Referring to
Referring back to
When the pressure in annulus A is sufficient to overcome the biasing force of the biasing member 335 and the force from the annulus B pressure, the piston 320 is retracted to open the inflow port 318 and place the inflow port 318 in fluid communication with the relief port 315.
The relief port 315 is closed when the net force acting on the piston 320 (due to pressure differential between annulus A and annulus B and to the spring force) decreases to a threshold closing force sufficient to release the collet 323, which in turn, returns the piston 320 to the closed position. Because the collet 323 helps to retain the piston 320 in the open position, the pressure differential between annulus A and annulus B required to close the port 315 is smaller than the pressure differential required to open the port 315. If the pressure in annulus A decreases, the port 315 will remain open as long as the pressure differential is greater than the closing pressure differential. In this manner, the valve assembly 300 is operable as a one-way valve that permits fluid flow into the bore 301 of the valve assembly 300 but prevents fluid flow out of the bore 301 via the relief port 315. The valve assembly 300 is automatically resettable downhole and may be operated multiple times in response to pressure fluctuations within the wellbore 5. As stated above, any of the casings 10, 20, 30 and/or the tubular members 40, 45 may each be provided with one or more valve assemblies 300 to allow fluid flow from a surrounding casing or tubular member to an inner casing or tubular member, while preventing fluid flow in the opposite direction.
The retaining member 423 is coupled to the body portion 421 and is configured to retain the piston 420 in the open position. In this embodiment, the retaining member is an o-ring 423 that may be disposed in a recess in the body portion 421. The o-ring 423 is compressed when disposed in the smaller diameter section of the chamber 313. When the piston 420 is retracted to open the inflow port 318, the o-ring 423 is moved to the larger diameter section 312 of the chamber 313, whereby the o-ring is allowed to expand outward to engage the shoulder 344. In this respect, the o-ring 423 can help maintain the piston 420 in the open position. The relief port 315 is closed when the forces acting on the piston 320 due to pressure differential between annulus A and annulus B and to the spring force decreases to a threshold closing force sufficient to compress the o-ring 423 sufficiently to allow the o-ring 423 to move into the smaller diameter section of the chamber 313.
The retaining member 523 is coupled to the body portion 521 and is configured to assist with retaining the piston 520 in the open position. In this embodiment, the retaining member is a snap ring 523 that is disposed in a recess in the body portion 521. The snap ring 523 is compressed when disposed in the smaller diameter section 311 of the chamber 313. When the piston 520 is retracted to open the inflow port 318, the snap ring 523 is moved to the larger diameter section 312 of the chamber 313, whereby the snap ring 523 is allowed to expand outward to engage the shoulder 344. In this respect, the snap ring 523 can help maintain the piston 520 in the open position. The relief port 315 is closed when the forces acting on the piston 320 due to pressure differential between annulus A and annulus B and to the spring force decreases to a threshold closing force sufficient to compress the snap ring 523 sufficiently to allow the snap ring 523 to move into the smaller diameter section of the chamber 313.
In yet another embodiment, the valve assembly 700 of
In any of the embodiments described herein, any of the casings 10, 20, 30 and/or the tubular members 40, 45 may each be provided with one or more valve assemblies 300 and 700 to allow fluid flow from a surrounding casing or tubular member to an inner casing or tubular member, while preventing fluid flow in the opposite direction. In one embodiment, a casing or tubular member may be provided with multiple valve assemblies that are spaced apart along the length of the casing or tubular member. The valve assemblies 300 and 700 may be operable to open and/or close at different pre-determined pressure setting.
Embodiments of the valve assemblies 300 and 700 may be used to prevent collapse of a casing. For example, during an uncontrolled flow situation such as a catastrophic blowout, the hot hydrocarbon fluids from lower portions of the well may heat the fluid which is trapped in the annular space between an outer casing and an inner casing. The annular space may extend from top of the cement level to liner hanger. If the inner casing extends to the surface, then the annul area may extend from the top of the cement level and up to the surface. When the trapped fluid in the annular space is heated by the hot hydrocarbon fluids, the trapped fluid will expand. In some instances, this expansion can collapse the inner casing, thereby making future mitigation of the well more problematic. In this situation, presence of the valve assemblies 300 and 700 allow the inner casing to bleed the pressure caused by the heat expansion. As a result, easier methods such as a capping stack can be used to get the well under control again.
In one or more embodiments described herein, the valve assembly is configured to open at a predetermined pressure differential, thereby to preventing burst or collapse of the casings and/or tubular members.
In one embodiment, the valve assembly includes a tubular body having a port for fluid communication between an exterior of the tubular body and an interior of the tubular body; a chamber formed in a wall of the tubular body, the chamber in fluid communication with the port; a closure member disposed in the chamber and configured to control fluid communication through the port in response to a pressure differential; and a retaining member coupled to the closure member for retaining the closure member in an open position.
In one or more of the embodiments described herein, the valve assembly includes a biasing member for biasing the closure member in a closed position.
In one or more of the embodiments described herein, the valve assembly may include a plug disposed on an end opposite the closure member.
In one or more of the embodiments described herein, the activation force of the closure member is adjustable. In one or more of the embodiments described herein, the activation force may be adjusted by changing a location of the plug. In another embodiment, the activation force may be adjusted by changing a length of the piston.
In one or more of the embodiments described herein, the retaining member is configured to retain the closure member in the open position until reaching a predetermined differential pressure between the exterior and the interior of the valve assembly.
In one or more of the embodiments described herein, the retaining member is configured to engage a wall of the chamber to retain the closure member in the open position.
In one or more of the embodiments described herein, the retaining member is selected from the group consisting of a collet, an o-ring, a snap ring, and combinations thereof.
In another embodiment, a method of operating a valve assembly includes coupling a valve assembly to a casing and the valve assembly having a tubular body having a port for fluid communication between an exterior of the valve assembly and an interior of the valve assembly; a chamber formed in a wall of the tubular body, the chamber in fluid communication with the port; a closure member disposed in the chamber and configured to control fluid communication through the port; and a retaining member coupled to the closure member for retaining the closure member in an open position. The method further includes opening the valve assembly in response to a predetermined pressure differential between the exterior and the interior of the valve assembly, and retaining the closure member in the open position.
In one or more of the embodiments described herein, the method further includes closing the valve assembly in response to a second predetermined pressure differential.
In one or more of the embodiments described herein, the predetermined pressure differential to open the valve assembly is different from the second predetermined pressure differential to close the valve assembly.
In one or more of the embodiments described herein, the method further includes repeatedly opening and closing the valve assembly in response to respective predetermined pressure differentials.
In one or more of the embodiments described herein, a second pressure differential to close the port is smaller than the predetermined pressure differential.
In one or more of the embodiments described herein, a net force acting on the closure member is sufficient to release the retainer member.
While the foregoing is directed to embodiments of the invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
Claims
1. A valve assembly, comprising:
- a tubular body having a port for fluid communication between an exterior of the tubular body and an interior of the tubular body;
- a chamber formed in a wall of the tubular body, the chamber in fluid communication with the port;
- a closure member disposed in the chamber and configured to allow fluid communication through the port in response to a predetermined pressure differential; and
- a retaining member coupled to the closure member for retaining the closure member in an open position.
2. The valve assembly of claim 1, wherein the retaining member is configured to engage a wall of the chamber to retain the closure member in the open position.
3. The valve assembly of claim 1, further comprising a biasing member for biasing the closure member in a closed position.
4. The valve assembly of claim 3, wherein the biasing member is disposed between the closure member and a plug.
5. The valve assembly of claim 1, wherein the closure member comprises a piston.
6. The valve assembly of claim 1, wherein a second pressure differential to close the port is smaller than the predetermined pressure differential.
7. The valve assembly of claim 1, wherein the retainer member is expandable.
8. The valve assembly of claim 1, wherein the retaining member is selected from the group consisting of a collet, an o-ring, a snap ring, and combinations thereof.
9. The valve assembly of claim 1, wherein an activation force of the closure member is adjustable.
10. The valve assembly of claim 9, wherein the activation force is adjusted by changing a location of a plug disposed on an end opposite the closure member.
11. The valve assembly of claim 9, wherein the activation force is adjusted by changing a length of the closure member.
12. The valve assembly of claim 1, wherein the closure member includes a sealing member configured to seal the port.
13. The valve assembly of claim 12, wherein the closure member further comprises a second sealing member for engaging the chamber.
14. The valve assembly of claim 13, further comprising a plug having a third sealing member for engaging the chamber.
15. The valve assembly of claim 14, further comprising a biasing member disposed between the closure member and a plug.
16. The valve assembly of claim 15, wherein the biasing member is disposed between the second sealing member and the third sealing member.
17. The valve assembly of claim 1, wherein the retainer member is configured to allow the closure member to close the port when a pressure differential is below the predetermined pressure differential.
18. A method of controlling fluid communication through a port, comprising:
- closing the port using a closure member movable in a chamber;
- opening the port at a predetermined pressure differential, wherein the closure member moves from a closed position to an open position;
- retaining the closure member in the open position using a retainer member; and
- moving the closure member to the closed position when a pressure differential is below the predetermined pressure differential, thereby closing the port.
19. The method of claim 18, wherein the retainer member is movable with the closure member.
20. The method of claim 18, wherein retaining the closure member in the open position comprises engaging the retainer member with a shoulder in the chamber.
21. The method of claim 18, wherein closing the port comprises biasing the closure member in the closed position using a biasing member.
22. The method of claim 18, wherein a first fluid pressure is applied to the closure member to open the port is larger than a second fluid pressure acting on the closure member to close the port.
23. The method of claim 18, wherein a net force acting on the closure member is sufficient to release the retainer member.
24. A method of operating a valve assembly, comprising:
- coupling a valve assembly to a casing, the valve assembly having: a tubular body having a port for fluid communication between an exterior of the tubular body and an interior of the tubular body; a chamber in fluid communication with the port; and a closure member disposed in the chamber and configured to control fluid communication through the port;
- opening the port in response to a predetermined pressure differential between the exterior and the interior of the tubular body, and
- retaining the closure member in the open position using a retaining member.
Type: Application
Filed: Sep 19, 2014
Publication Date: Mar 26, 2015
Inventor: Stephanie Dianne WIND (Houston, TX)
Application Number: 14/491,897
International Classification: E21B 34/08 (20060101); E21B 33/12 (20060101);