Abstract:
A flapper valve preferably used in injection application in deep subterranean locations has an actuating sleeve with a seat to accept an object. A j-slot connects the actuation sleeve movement to the housing so that with an object on the seat and an applied pressure cycle the sleeve moves the flapper to the open position. The plug is dissolved and the injection begins. The plug can have an opening so as to allow continuous injection flow as the flapper is operated. Closing the flapper involves a second object on the same seat and a pressure cycle so that a spring can push the sleeve away from the flapper to allow a torsion spring on the flapper to close it.

Description:
FIELD OF THE INVENTION 
       [0001]    The field of this invention is valves for subterranean use that are actuated with an indexing mechanism and more particularly flapper type valves actuated with pressure cycles on a plug that can be removed after use. 
       BACKGROUND OF THE INVENTION 
       [0002]    Various valve designs used in the past have incorporated sleeves indexed by j-slot devices to selectively align and misalign ports. In one example the ball that lands on a seat to allow application of pressure cycles to operate the j-slot is blown through the seat after a change in valve position. This is illustrated in U.S. Pat. No. 7,416,029. Another device is in essence a sliding sleeve that allows flow uphole and the sleeve, which is mounted to a j-slot, can be cycled from uphole as flow from uphole acts to close a flapper on top of the sleeve for pressure cycling. This is shown in US Publication 2008/0196898. 
         [0003]    Other designs use a j-slot to unlock a lock in conjunction with a plug that can then disappear as illustrated in U.S. Pat. Nos. 5,765,641; 6,119,783 and 6,026,903. Other designs use relatively movable mandrel components where cycles of picking up and setting down weight actuate a j-slot to operate a flapper, as shown in U.S. Pat. No. 4,458,762. Some designs use a j-slot to unlock a lock so that a flapper can then operate. A plug is landed on a seat which then is dissolved. Some examples of combinations of some of these features are U.S. Pat. Nos. 7,270,191; 6,904,975 and US Publication 2009/0242199. 
         [0004]    Other designs provide a flowpath constriction to create differential pressure on a flow tube to open a flapper. These designs such as the MC Injection Valves from Halliburton and the A Series Injection Valve from Schlumberger restrict access through the valve for advancing other tools. The Model J Wireline Retrievable Injection Valve from Baker Hughes opens on a predetermined flow through a restriction. Some hydraulically operated safety valves had a feature to lock a flapper open after the flapper was displaced with a flow tube driven by a hydraulic piston. In this design shown in U.S. Pat. No. 6,902,006 the flame holding the flapper was itself shifted when the flapper was open to catch the edge of the flapper in a top groove of a sleeve below. Yet a few other applications that use flow bore restrictions to create a force to move a tube to open a flapper are U.S. Ser. Nos. 12/433,134, filed on Apr. 30, 2009 entitled Innovative Flow Tube, 12/469,310, filed on May 20, 2009, entitled Flow-Actuated Actuator, and 12/469,272, filed on May 20, 2009, entitled Flow-Actuated Actuator and Method. 
         [0005]    The present invention deals with flapper type valves with a preferred use in injection service. The design provides a way of operating the flapper without control lines. In deep applications there will be high hydrostatic pressure in the control line that would have to be offset with a very large return spring. While a dual control line system can offset this hydrostatic effect in deep applications there is additional expense and operational issues from doubling up the control lines and running them with a string into the subterranean location. In the preferred embodiment there is no need for control lines. A flapper is operated by a sleeve that responds to pressure cycles against a seated ball or plug to push the flapper open after a predetermined number of cycles. The ball, plug or other object is removed from its blocking position on a seat preferably by dissolving it so that flow can commence. The preferred application is injection service where water, salt water, chemicals, CO 2  or steam can be the flowing fluid. When it is desired to close the flapper another object can be landed in the same seat and the cycling with pressure repeated to allow a return spring to raise the flow tube so that a torsion spring on the flapper pivot can move the flapper to the closed position against its seat. As few as a single application and removal of pressure cycle can be used to change the flapper position between open and closed. 
         [0006]    In an alternative embodiment an actuation sleeve pushes the flapper open as well as engaging or contacting a counter sleeve below that is engaged to a j-slot. On release of pressure a return spring on the counter sleeve raises it to retain the flapper in the open position while a separate return spring biases the actuation sleeve up. A second ball or other object landed in the seat of the actuation sleeve once again displaces the actuation sleeve against the counter sleeve. This time the counter sleeve is held against its return spring by the j-slot so that on release of pressure the torsion spring on the flapper allows the flapper to pivot closed when the actuation sleeve is also pushed up by its return spring. After a use of either the first or the second object, either is removed preferably by dissolving to get either object out of the flow path. 
         [0007]    The dissolving of the object can occur by fluids such as water, saltwater in the wellbore, acid added to the wellbore, or by other reactive or dissolving agents present or added to the wellbore. Other ways to fail the object to get it out of the flow path are also contemplated. 
         [0008]    Those skilled in the art will better appreciate the scope of the invention from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is determined by the appended claims. 
       SUMMARY OF THE INVENTION 
       [0009]    A flapper valve preferably used in injection application in deep subterranean locations has an actuating sleeve with a seat to accept an object. A j-slot connects the actuation sleeve movement to the housing so that with an object on the seat and an applied pressure cycle the sleeve moves the flapper to the open position. The plug is dissolved and the injection begins. The plug can have an opening so as to allow continuous injection flow as the flapper is operated. Closing the flapper involves a second object on the same seat and a pressure cycle so that a spring can push the sleeve away from the flapper to allow a torsion spring on the flapper to close it. In an alternative embodiment an actuation sleeve pushes a counter sleeve that is movable through a j-slot. The first object on the actuation sleeve pushes both sleeves such that removal of pressure allows the now open flapper to be retained in the open position and the object to be dissolved or otherwise removed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  is a section view with the flapper closed; 
           [0011]      FIG. 2  is the view of  FIG. 1  after the object is landed on the actuation sleeve and the sleeve is displaced to compress the return spring; 
           [0012]      FIG. 3  shows the object dissolved and the passage through the sleeve cleared; 
           [0013]      FIG. 4  is an unrolled view of the track for the j-slot for the actuation sleeve; 
           [0014]      FIG. 5  is the flapper closed view for run in using an alternative embodiment that moves an actuation sleeve against a counting sleeve where the counting sleeve is on a j-slot; 
           [0015]      FIG. 6  is the view of  FIG. 5  with an object on the seat on the actuation sleeve and both sleeves displaced as pressure is applied; 
           [0016]      FIG. 7  is the view of  FIG. 6  with applied pressure removed and the object dissolved showing the counting sleeve holding the flapper open; 
           [0017]      FIG. 8  is an unrolled version of the counting sleeve j-slot track showing a straight lower end; and 
           [0018]      FIG. 9  is an alternative embodiment to  FIG. 8  where the lower end of the counting sleeve is scalloped to enhance the amount of protrusion over the flapper when the flapper is retained in the open position. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0019]      FIG. 1  has a housing  10  with a passage  12  and a flapper  14  that pivots on a pin  16 . A torsion spring  18  biases the flapper  14  toward the closed position against the seat  20 . An actuating sleeve  24  is slidably mounted in the passage  12  to move against the bias of a return spring  26  when an object such as a ball or plug  28  lands and obstructs the passage  12  at seat  30  as shown in  FIG. 2 . A pin or screw  32  extends into a j-slot track  34  that is shown rolled open in  FIG. 4 . The j-slot track  34  has a series of long passages  36  and short passages  38  that alternate. In the  FIG. 1  position, the actuating sleeve  24  is at its highest location where spring  26  is extended and the flapper  14  is biased by spring  18  against the seat  20 . This can happen because the actuating sleeve  24  in  FIG. 1  is not in contact with the flapper  14 . In essence the spring  26  advances the actuating sleeve  24  until the long passage  36  hits the pin  32 , as shown in  FIG. 1 . 
         [0020]    Dropping the object  28  onto seat  30  and applying pressure moves the sleeve  24  axially and initially without rotation as the long passage  36  with pin  32  extending into it guides the axial movement. When the pin advances to passage  40  there is rotation of the sleeve  24  as the pin enters passage  42  and remains there as long as pressure is held against the object  28 . When the pressure is removed in passage  12  on the object  28  the sleeve  24  reverses direction and resumes rotation as the pin  32  rides in passage  44  on the way to passage  38 . This is the  FIG. 2  position. 
         [0021]    The object  28  is then removed from the seat  30  in one of a variety of ways such as dissolving, chemical reaction, melting, or being ejected through the seat  30 . Note that the sleeve  24  has been pushed down to contact the flapper  14  and rotate it 90 degrees so that in  FIG. 2  it is behind the sleeve  24  with the spring  26  being compressed. The position of  FIG. 2  is held because the pin  32  in short passage  38  is at the end of that passage with the sleeve  24  under a spring force.  FIG. 3  is the view of  FIG. 2  after the object  28  is no longer on the seat  30 . Injection of fluid down passage  12  or production in the opposite direction can now take place as indicated by arrow  46 . 
         [0022]    Those skilled in the art will appreciate that a single application and removal of pressure cycle has gotten the flapper  14  to go from closed to open and that the landing of a second object (not shown) on seat  30  followed by a pressure cycle of application and removal of pressure will get the pin  32  into the next long passage  36  to allow the sleeve  24  to rise up and away from the flapper  14  so that the torsion spring  18  can close the flapper  14  against its seat  20 . While the j-slot  34  is designed for a single cycle of pressure application and removal to move the flapper  14  the j-slot  34  can be designed for multiple cycles before the flapper moves. Since the second object (not shown) lands on the same seat  30 , it can have the same shape as the object  28 . 
         [0023]    As an option to avoid stopping injection when trying to close the flapper while landing a second object (not shown) on seat  30 , a small passage  46  (illustratively shown on object  28  but is actually used in the second object that is not shown) is put in so that there is some injection flow through it but the pressure difference across the object is sufficient to move the sleeve  24  so that it can be raised when pressure is removed so that the flapper  14  can close. If such a passage is used it is preferred that the object shape not be round but instead be a cylindrical plug for example so that the passage  46  is in fluid communication with the passage  12  when the object (not shown) lands on seat  30  as the second landed object. 
         [0024]      FIGS. 4-9  show an alternative embodiment. Here there is an actuating sleeve  124  biased by a spring  126  but with no j-slot mechanism. As before there is a flapper  114  on a pivot  116  that has a torsion spring  118 . The flapper seats on seat  120 . Below the flapper  114  there is a counting sleeve  50  biased by a spring  52 . A pin  54  extends into a j-slot  56  that is shown rolled out in  FIGS. 8 and 9 . When the first object  128  lands on seat  130  and pressure is applied in passage  112  the actuating sleeve  124  is pushed down to compress the spring  126  and to push the flapper  114  90 degrees to the open position behind the sleeve  124  as shown in  FIG. 6 . That same movement of sleeve  124  that opened the flapper  114  has resulted in the lower end  58  hitting the upper end  60  of the counting sleeve  50  and pushing it in tandem with sleeve  124  while compressing the spring  52 . In the  FIG. 5  position the pin  54  is in the short passage  62 . As pressure is applied to the object  128  the sleeve  50  initially moves axially without rotation as pin  54  guides the passage  62  until passage  64  is reached at which time there is translation and rotation followed by translation only as the passage  66  runs past the pin  54 . Once the pressure in passage  112  is let off the object  128 , the spring  126  pushes up sleeve  124 , while the spring  52  pushes up sleeve  50 . Sleeve  50  initially only translates down as pin  54  tracks path  66  in the opposite direction before going into path  68  which causes the sleeve  50  to advance axially while rotating until pin  54  reaches path  70  where there is only axial motion of sleeve  50  without rotation. The upper end  60  of sleeve  50 , while initially moving in tandem with sleeve  124 , stops moving when the upper end  60  is in front of the flapper  114  so that rotation of the flapper from the open position is prevented. The sleeve  124  moves away from the now stationary sleeve  50  until the sleeve  124  resumes its original position. These movements are illustrated in  FIG. 7  which also shows that the initial object  128  has been removed using any of the techniques described before. Flow in passage  112  can now occur as indicated by arrow  72 . As before, dropping a second object on seat  130  and another pressure cycle gets the device back to the  FIG. 5  position and the second object (not shown) can then be removed using the previously described techniques. 
         [0025]      FIGS. 8 and 9  are identical except for the variation of  FIG. 9  having a scalloped end  74  having peaks  76  and alternating valleys  78 . This feature extends the reach of the sleeve  50  toward the flapper  114  when the pin  54  is in the long slots  70 . 
         [0026]    Those skilled in the art will appreciate that the device eliminated the need for a hydraulic control system including control lines and a piston to move the sleeves for operating the flapper. The springs in the design simply offset the weight of the sleeve that they bias independent of the depth of the application. The passage is cleared after the operation of the flapper so that preferably injection can take place with the flapper held open. A second object can be used to release the flapper so it can close. A passage in the object can be optionally provided to continue injection flow with the object being seated. Dissolving the object with an introduced fluid is the preferred way to reopen the flowpath. 
         [0027]    The above description is illustrative of the preferred embodiment and many modifications may be made by those skilled in the art without departing from the invention whose scope is to be determined from the literal and equivalent scope of the claims below: