WATER HAMMER MITIGATING FLOW CONTROL STRUCTURE AND METHOD
A water hammer mitigating flow control structure for a downhole completion including a tubular member configured for the downhole environment. A valve member in operable communication with the tubular member and positionable with respect to the tubular member to allow or prevent fluid movement through the tubular member. An absorber in operable communication with the valve member and configured to allow movement of the valve member the movement absorbing a pressure rise against the valve member in use. Also included is a method for mitigating water hammer in a flow control structure for a downhole completion
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For many industries where fluids are managed in pipelines of various sorts and with actuable valves to permit and prevent fluid flow, water hammer is a problem. The commonly termed water hammer is a tube wave created when a flow of fluid is suddenly stopped by a structure such as a valve. Upstream of the valve, fluid continues to move into the closed valve, increasing pressure in a local volume of fluid, which pressure propagates as a wave back in the upstream direction potentially causing damage as it propagates and when it reflects off other structures. Downstream of the valve the fluid also continues to move thereby creating a localized low-pressure in the fluid, which also can propagate as a wave in the downstream direction. In extreme cases, cavitation can occur at the downstream side of the valve with all of the intrinsic problems that are known to practitioners.
In the drilling and completion arts, water hammer can be a significant problem for a number of different components of downhole systems such as safety valves for example. Means to address water hammer would be well received by the art.
SUMMARYA water hammer mitigating flow control structure for a downhole completion including a tubular member configured for the downhole environment; a valve member in operable communication with the tubular member and positionable with respect to the tubular member to allow or prevent fluid movement through the tubular member; and an absorber in operable communication with the valve member and configured to allow movement of the valve member the movement absorbing a pressure rise against the valve member in use.
A method for mitigating water hammer in a flow control structure for a downhole completion including allowing a valve member to move relative to a tubular member with which the valve member is operable to allow or prevent fluid movement through the tubular member; absorbing a pressure rise against the valve member with the movement.
Referring now to the drawings wherein like elements are numbered alike in the several Figures:
In each of the following embodiments it is to be noted that the “ringing” of the water hammer effect is mitigated. In some applications the most important place to mitigate that ringing is where the formation is directly exposed thereto. For example, in an injection system, a ringing downhole of the injection valve is detrimental to the formation. Mitigation of the ringing downhole of the valve would accordingly be of paramount importance. Ringing in other parts of the system may also however be of detrimental effect and might advantageously be mitigated as well. Some of the embodiments below will mitigate water hammer in either or both directions.
Referring to
Returning to discussion of
It will be appreciated from the view of
Although the absorber 16 is illustrated as a coil spring, it is contemplated that the absorber 16 may comprise other configurations such as a gas spring, a rubber spring, capillary spring or other resilient configurations. It is further noted that the spring rate may be constant or variable in embodiments. In each iteration, the valve member 14 will be allowed to move in at least one direction and in some embodiments will be allowed to move in both directions, and in either case, will be decelerated to a stop gradually after movement begins pursuant to a valve closure.
It is noted that most of the discussion herein is related to the pressure rise on the upstream side of the valve member 14. It will be appreciated however that the same action that mitigated that rise on the upstream side of the valve member will mitigate the low-pressure event caused at the downstream side of the valve member in a prior art system. This is because the valve member is following the fluid in the downstream direction and therefore not allowing the fluid to pull the pressure down in the local area immediately downstream of the valve member 14, as it would do in a fixed valve member prior art system.
In another embodiment, referring to
In another embodiment, referring to
It is further noted that each embodiment where there is a resilient absorber, a dashpot, and particularly a single acting dashpot that allows rapid initial movement but slows the return movement of the valve member, could be added to damp the resilience particularly upon the rebound stroke after compression of the absorber due to valve closure.
While one or more embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
Claims
1. A water hammer mitigating flow control structure for a downhole completion comprising:
- a tubular member configured for the downhole environment;
- a valve member in operable communication with the tubular member and positionable with respect to the tubular member to allow or prevent fluid movement through the tubular member; and
- an absorber in operable communication with the valve member and configured to allow movement of the valve member the movement absorbing a pressure rise against the valve member in use.
2. A water hammer mitigating flow control structure as claimed in claim 1 wherein the valve member is a flapper valve.
3. A water hammer mitigating flow control structure as claimed in claim 1 wherein the valve member is a ball valve.
4. A water hammer mitigating flow control structure as claimed in claim 1 wherein the absorber is of constant rate.
5. A water hammer mitigating flow control structure as claimed in claim 1 wherein the absorber is of variable rate.
6. A water hammer mitigating flow control structure as claimed in claim 1 wherein the absorber is positioned downstream of fluid flow relative to the valve member.
7. A water hammer mitigating flow control structure as claimed in claim 1 wherein the absorber is positioned both upstream and downstream of the valve member.
8. A water hammer mitigating flow control structure as claimed in claim 7 wherein the absorber is two absorbers with one positioned upstream and one positioned downstream of the valve member.
9. A water hammer mitigating flow control structure as claimed in claim 1 wherein the absorber is a spring.
10. A water hammer mitigating flow control structure as claimed in claim 9 wherein the spring is a coil spring.
11. A water hammer mitigating flow control structure as claimed in claim 1 wherein the absorber is a gas charged chamber.
12. A water hammer mitigating flow control structure as claimed in claim 1 wherein the absorber further includes a dash pot.
13. A water hammer mitigating flow control structure as claimed in claim 12 wherein the dash pot is single acting.
14. A water hammer mitigating flow control structure as claimed in claim 1 wherein the structure further includes a housing radially adjacent the tubular member having one or more openings therein that are covered until the tubular member is moved following a pressure rise against the valve member in use.
15. A water hammer mitigating flow control structure as claimed in claim 14 wherein the one or more openings absorb pressure when exposed to fluid pressure subsequent to the valve member experiencing a pressure rise in use.
16. A water hammer mitigating flow control structure as claimed in claim 1 wherein the pressure rise is an origination or a reflection of a tube wave.
17. A method for mitigating water hammer in a flow control structure for a downhole completion comprising:
- allowing a valve member to move relative to a tubular member with which the valve member is operable to allow or prevent fluid movement through the tubular member;
- absorbing a pressure rise against the valve member with the movement.
18. A method for mitigating water hammer in a flow control structure as claimed in claim 17 wherein the absorbing includes deforming a spring.
19. A method for mitigating water hammer in a flow control structure as claimed in claim 17 wherein the deforming includes deforming a spring at a downstream position relative to the valve member.
20. A method for mitigating water hammer in a flow control structure as claimed in claim 17 wherein the deforming includes deforming a spring at both downstream and upstream positions relative to the valve member.
21. A method for mitigating water hammer in a flow control structure as claimed in claim 17 wherein upon deforming the spring in the downstream position, one or more openings in a housing of the structure are uncovered.
22. A method for mitigating water hammer in a flow control structure as claimed in claim 17 wherein the absorbing includes a rebound and the rebound is slowed.
Type: Application
Filed: Jun 7, 2011
Publication Date: Dec 13, 2012
Applicant: BAKER HUGHES INCORPORATED (Houston, TX)
Inventors: Terry R. Bussear (Spring, TX), Keith J. Murphy (Simsbury, CT)
Application Number: 13/155,007
International Classification: E21B 34/06 (20060101);