Patent Application
20110232916
The present disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides a bi-directional flapper/sealing mechanism and associated technique.
It is sometimes desirable to isolate one section of a wellbore from another. For example, it may be useful to isolate an uncased section of a wellbore from an upper section of the wellbore while a drill string is tripped out of, and into, the wellbore. In this manner, swab and surge effects will not damage the uncased section, fluids will not be produced from a formation into the wellbore, etc.
Isolation valves have been used for these purposes, and others, in the past. However, the construction of prior isolation valves has not always been entirely satisfactory, in some instances because of operational problems, unreliability, etc.
Therefore, it will be appreciated that improvements are needed in the art of constructing isolation valves.
Representatively illustrated in
An isolation valve 14 is interconnected in a tubular string 16 (such as casing) which lines the upper section 12a. The isolation valve 14 could be interconnected in the tubular string 16 as it is installed in the wellbore 12, or the isolation valve could be secured in the tubular string after the tubular string is installed in the wellbore (for example, by interconnecting the isolation valve in a liner string which is secured to the casing by a liner hanger, etc.)
Note that the term “casing” is meant to encompass any protective wellbore lining. Casing can include tubular materials known as tubing, liner, casing, etc. Casing can be continuous or segmented, and can be formed in situ. Casing can have lines (such as electrical, hydraulic, fiber optic, etc. lines) in a sidewall thereof, or on an interior or exterior thereof, for actuation of the isolation valve 14.
The isolation valve 14 in the system 10 selectively isolates the uncased section 12b from the cased section 12a, for example, while a drill string (not shown) is tripped out of, and into, the wellbore 12 in a drilling operation. However, this is only one possible use for the isolation valve 14.
Another possible use would be isolating a completed wellbore section from a wellbore section above a production packer in a completion operation (e.g., in order to prevent loss of completion fluids and damage to a completed interval, etc.). Thus, it should be clearly understood that the well system 10 depicted in
Referring additionally now to
The isolation valve 14 as depicted in
Note that the piston 22 is not necessarily annular-shaped. Other types of pistons (such as, concentric or rod pistons, etc.) may be used in keeping with the principles of this disclosure.
In
A tubular actuator member 32 extends downwardly from the piston 22. It is not necessary for the member 32 to be tubular, or for the member to be directly connected to (or to be formed as part of) the piston 22, or for the member to be displaced by the piston. However, the member 32 preferably does displace when the isolation valve 14 is actuated between its open and closed configurations.
The closure assembly 20 includes a closure member 34 which is pivotably connected to the actuator member 32 by a pivot 36. In the open configuration depicted in
In the examples of
Note that, in the closed configuration depicted in
The pressure differential from the upper chamber 24 to the lower chamber 26 biases the piston 22 downwardly to thereby compress the closure member 34 between the seats 44, 46. In this manner, both upward and downward flow through the passage 38 is preferably prevented in the closed configuration.
However, once the closure member 34 is in its closed position as depicted in
It should be clearly understood that the seats 44, 46 are not necessarily positioned as depicted in
A profile 48 is preferably formed in the housing 42, and is appropriately shaped, so that it urges the closure member 34 toward its closed position (i.e., pivoting radially inward) when the piston 22 and actuator member 32 displace the closure member downward. The profile 48 is conical shaped as depicted in
Use of the profile 48 is preferred over use of a spring (such as a torsion spring encircling the pivot 36, etc.) to bias the closure member 34 toward its closed position. This is due to the fact that use of springs to displace large diameter flappers has been problematic in prior valves. However, a spring could be used in the isolation valve 14, as an alternative to (or in addition to) the profile 48, without departing from the principles of this disclosure.
It may now be fully appreciated that the above disclosure provides several advancements to the art of constructing and utilizing isolation valves in subterranean wells. The example isolation valve 14 described above is straightforward and reliable in operation, with relatively few moving parts, yet it conveniently provides the advantage of selectively permitting and preventing flow in both directions through the passage 38 when closed.
In particular, the above disclosure provides to the art an isolation valve 14 for use in a subterranean well. The isolation valve 14 can include a pivot 36 connecting a closure member 34 to an actuator member 32 which displaces when the isolation valve 14 is actuated between open and closed configurations. The pivot 36 preferably displaces with the actuator member 32.
The isolation valve 14 can also include a profile 48 formed therein. The profile 48 biases the closure member 34 from an open position to a closed position when the isolation valve 14 is actuated from the open configuration to the closed configuration.
The closure member 34 may comprise a flapper which pivots about the pivot 36 when the isolation valve 14 is actuated between the open and closed configurations.
In the closed configuration, the closure member 34 can be sealingly engaged with a first seat 44 on one side of the closure member, and the closure member 34 can be sealingly engaged with a second seat 46 on an opposite side of the closure member. The first seat 44 may be carried on the actuator member 32.
In the closed configuration, the closure member 34 may prevent fluid flow through a passage 38 extending longitudinally through the isolation valve 14, with the closure member 34 preventing the fluid flow in first and second opposite longitudinal directions through the passage 38.
Also described by the above disclosure is an isolation valve 14 which can include a pivot 36 connecting a closure member 34 to an actuator member 32 which displaces when the isolation valve 14 is actuated between open and closed configurations. A profile 48 may be formed in the isolation valve 14. The profile 48 may bias the closure member 34 from an open position to a closed position when the isolation valve 14 is actuated from the open configuration to the closed configuration.
The above disclosure also describes a method of actuating an isolation valve 14 in a subterranean well. The method can include actuating the isolation valve 14 between open and closed configurations, wherein actuating the isolation valve 14 comprises simultaneously displacing an actuator member 32, a closure member 34, and a pivot 36 which pivotably connects the closure member to the actuator member.
The method may also include interconnecting the isolation valve 14 in a tubular string 16, the tubular string being installed in the well.
Actuating the isolation valve 14 can include a profile 48 formed in the isolation valve biasing the closure member 34 from an open position to a closed position when the isolation valve 14 is actuated from the open configuration to the closed configuration.
The closure member 34 may comprise a flapper which pivots about the pivot 36 when the isolation valve 14 is actuated between the open and closed configurations.
The method can also include sealingly engaging the closure member 34 with a first seat 44 on one side of the closure member, and sealingly engaging the closure member 34 with a second seat 46 on an opposite side of the closure member.
Actuating the isolation valve 14 may include carrying the first seat 44 on the actuator member 32.
The method can include the closure member 34 preventing fluid flow through a passage 38 extending longitudinally through the isolation valve 14 in the closed configuration, and the closure member 34 preventing the fluid flow in first and second opposite longitudinal directions through the passage 38.
It is to be understood that the various embodiments of the present disclosure described herein may be utilized in various orientations, such as inclined, inverted, horizontal, vertical, etc., and in various configurations, without departing from the principles of the present disclosure. The embodiments are described merely as examples of useful applications of the principles of the disclosure, which is not limited to any specific details of these embodiments.
In the above description of the representative embodiments of the disclosure, directional terms, such as “above,” “below,” “upper,” “lower,” etc., are used for convenience in referring to the accompanying drawings. In general, “above,” “upper,” “upward” and similar terms refer to a direction toward the earth's surface along a wellbore, and “below,” “lower,” “downward” and similar terms refer to a direction away from the earth's surface along the wellbore.
Of course, a person skilled in the art would, upon a careful consideration of the above description of representative embodiments of the disclosure, readily appreciate that many modifications, additions, substitutions, deletions, and other changes may be made to the specific embodiments, and such changes are contemplated by the principles of the present disclosure. Accordingly, the foregoing detailed description is to be clearly understood as being given by way of illustration and example only, the spirit and scope of the present invention being limited solely by the appended claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| PCT/US10/28574 | Mar 2010 | US | national |
This application claims the benefit under 35 USC §119 of the filing date of International Application Serial No. PCT/US10/28574, filed Mar. 25, 2010. The entire disclosure of this prior application is incorporated herein by this reference.
