Patent Publication Number: US-8967269-B2

Title: Tubular valving system and method

Description:
BACKGROUND 
     Tubular systems often employ valves that allow fluid to flow through a tubular or to block fluid flow through the tubular. After closing a valve to block flow it is sometimes desirable to reopen the valve to reestablish flow therethrough. Doing so can be difficult in systems wherein the blockage is via a plug run within the tubular to a seat. Removal of the plug to reopen the tubular may require reversing flow to pump the plug back out through the pathway that it entered. Other options include milling or machining the plug out. Many methods, including the two foregoing require time (during reverse flow or running of a milling tool) to remove the blockage. This time could be spent more productively. Tubular valving systems and methods that overcome these drawbacks are well received in the art. 
     BRIEF DESCRIPTION 
     Disclosed herein is a tubular valving system. The system includes a tubular, a seat movably engaged with the tubular, a sleeve movably engaged with the seat between at least a first position, a second position and a third position, a release member in operable communication with the sleeve and the seat that maintains the sleeve relative to the seat in the first position until release thereof, a biasing member configured to urge the sleeve from the second position toward the third position, and a flapper sealingly engagable with the seat. Pressure greater than a first threshold level against the flapper when seated causes release of the release member allowing the sleeve and the seat to attain the second position. Subsequently, a drop in pressure against the seated flapper below a second threshold level allows the biasing member to move the sleeve relative to the seat to the third position thereby unseating the flapper from the seat and preventing the flapper from again seating with the seat. 
     Further disclosed herein is a method of actuating valves in a tubular system. The method includes, pressuring up against a flapper seated with a seat within a tubular to pressure greater than a first threshold pressure, releasing a release member fixedly attaching the seat to a sleeve, decreasing pressure below a second threshold pressure and moving the sleeve relative to the seat thereby opening the flapper. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following descriptions should not be considered limiting in any way. With reference to the accompanying drawings, like elements are numbered alike: 
         FIG. 1  depicts a cross sectional view of a tubular valving system disclosed herein illustrated in a closed position; 
         FIG. 2  depicts a cross sectional view of the tubular valving system of  FIG. 1  illustrated in an open position; and 
         FIG. 3  depicts a cross sectional view of an alternate tubular valving system disclosed herein illustrated in an open position. 
     
    
    
     DETAILED DESCRIPTION 
     A detailed description of one or more embodiments of the disclosed apparatus and method are presented herein by way of exemplification and not limitation with reference to the Figures. 
     Referring to  FIGS. 1 and 2 , an embodiment of a tubular valving system disclosed herein is illustrated at  10 . The valving system  10  includes, a tubular  14 , a seat  18 , a flapper  22  and a sleeve  26 . The seat  18  is movable relative to the sleeve  26  between at least a first position (shown in  FIG. 1 ), a second position (not shown) and a third position (shown in  FIG. 2 ). Initially a shoulder  28  of the seat  18  contacts a shoulder  32  of the tubular  14 . One or more release members  36 , shown herein as a plurality of shear screws; maintain the sleeve  26  relative to the seat  18  in the first position. Upon release of the release members  36 , the seat  18  is moved relative to the sleeve  26 , and the tubular  14 , until another shoulder  33  on the seat  18  contacts another shoulder  34  on the tubular  14 . A biasing member  40 , illustrated as a compression spring, biases the sleeve  26  relative to the seat  18  in an axial direction in the Figures. This biasing member  40  urges the sleeve  26  against the flapper  22  thereby defining the second position. The biasing member  40  having insufficient force to urge the flapper  22  open until pressure against the seated flapper  22  drops below a threshold pressure (as discussed further below) maintains the system  10  in the second position. It should be noted that urging of the biasing members  40  causes the shoulders  32  and  28  to be in contact prior to pressure against the flapper  22  causes a gap to form between the shoulders  32  and  28  and release of the release members  36 . 
     The foregoing structure allows pressure within the tubular  14 , upstream of the flapper  22  when seated on the seat  18  (leftward in the Figures), to increase thereby generating a force on the seat  18  relative to the sleeve  26 . The release members  36  support this force until a threshold pressure causes them to release. After release the seat  18  is moved by a dimension  44  relative to the tubular  14 . It should be noted that in both the first position and the second position the flapper  22  is seated against the seat  18  and thus pressure upstream thereof can be employed to do work such as actuating an actuator, or fracturing or treating a formation, for example, in a case where the invention is employed in a downhole hydrocarbon recovery system, for example. It should be further noted that pressure subsequent release of the release member  36  could be increased to pressures greater than the first threshold pressure. 
     A subsequent reduction in pressure below another threshold pressure allows the biasing member  40  to move the sleeve  26  and the seat  18  until the shoulder  28  again contacts the shoulder  32  thereby stopping the seat  18  from moving further. Continued movement of the sleeve  26  relative to the seat  18  causes the system  10  to move from the second position to the third position. As the sleeve  26  moves it causes the flapper  22  to pivotally open relative to the seat  18 . A shoulder  48  on the sleeve  26 , in this embodiment, contacts the shoulder  33  on the seat  18  to limit travel therebetween. The sleeve  26  holds the flapper  22  open and defines the third position. 
     Any practical number of the tubular valving systems  10  can be employed within the tubular  14 . Actuation of each of the systems  10  along the tubular  14  would then be actuatable, with nothing more than changes in pressure, in sequence starting with the most upstream one and moving downward toward the most downstream one of the systems  10 . Actuation as used herein means; pressuring up against the flapper  22 , releasing the release members  36 , pressuring up if desired to another pressure, and finally reducing pressure and allowing the sleeve  26  to move to the third position. 
     Referring to  FIG. 3 , an alternate embodiment of a tubular valving system is illustrated at  110 . The system  110  varies from that of system  10  by the addition of one or more hold-open elements  112 A,  112 B. The hold-open element  112 A can be in the form of a single elongated component, such as a coiled tubing or wireline, for example, an assembly of components, or alternately can be a plurality of separate hold-open elements  112 B, such as a collar as illustrated, with one being in operable communication with each of the flappers  22 . Regardless of the configuration of the hold-open element  112 A,  112 B the function is the same, to hold the flapper  22  open until the hold-open element  112 A,  112 B is moved to a location wherein it no longer holds the flapper  22  open. 
     The system  110  therefore allows for an altered operational sequencing relative to that of the system  10 . By employing a plurality of the systems  110  along the tubular  14 , for example, the sequence can be such that all the flappers  22  are initially open and then are made to actuate one at a time in order from the furthest downstream first to the furthest upstream last. Actuation of the systems  110  means moving the hold-open element  112 A,  112 B, closing the flapper  22 , pressuring up against the flapper  22 , releasing the release members  36 , pressuring up if desired to another pressure, and finally reducing pressure and allowing the sleeve  26  to move to the third position 
     While the invention has been described with reference to an exemplary embodiment or embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the claims. Also, in the drawings and the description, there have been disclosed exemplary embodiments of the invention and, although specific terms may have been employed, they are unless otherwise stated used in a generic and descriptive sense only and not for purposes of limitation, the scope of the invention therefore not being so limited. Moreover, the use of the terms first, second, etc. do not denote any order or importance, but rather the terms first, second, etc. are used to distinguish one element from another. Furthermore, the use of the terms a, an, etc. do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.