Abstract:
A ball type downhole lubricator valve features a ball rotating on its axis to open or close with control line pressure to an actuating piston. The ball is also shiftable to a locked open position. A cage surrounds the ball and retains opposed seats to it. The cage is made from one piece and tangential holes are drilled and tapped before the piece is longitudinally split with a wire EDM cutting technique. Fasteners to rejoin the cut halves properly space them to the original one piece internal dimension. Auxiliary tools allow determination of spacing of internal components so that a desired spring preload on the seats against the ball can be achieved.

Description:
PRIORITY INFORMATION 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 11/595,596 filed on Nov. 9, 2006. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The field of the invention relates to downhole lubricator valves that allow a string to be made up in a live well by isolation of a lower portion of it and more particularly to features regarding such valves relating to locking them, assembling them and component fabrication techniques. 
       BACKGROUND OF THE INVENTION 
       [0003]    Lubricator valves are valves used downhole to allow long assemblies to be put together in the well above the closed lubricator valve with well pressure further below the closed lubricator valve. These valves are frequently used in tandem with sub-surface safety valves to have redundancy of closures against well pressures below. 
         [0004]    Lubricator assemblies are used at the surface of a well and comprise a compartment above the wellhead through which a bottom hole assembly is put together with the bottom valve closing off well pressure. These surface lubricators have limited lengths determined by the scale of the available rig equipment. Downhole lubricators simply get around length limitations of surface lubricators by using a lubricator valve downhole to allow as much as thousands of feet of length in the wellbore to assemble a bottom hole assembly. 
         [0005]    In the past ball valves have been used as lubricator valves. They generally featured a pair of control lines to opposed sides of a piston whose movement back and forth registered with a ball to rotate it 90 between an open and a closed position. Collets could be used to hold the ball in both positions and would release in response to control pressure in one of the control lines. An example of such a design can be seen in U.S. Pat. Nos. 4,368,871; 4,197,879 and 4,130,166. In these patents, the ball turns on its own axis on trunnions. Other designs translate the ball while rotating it 90 degrees between and open and a closed position. One example of this is the 15K Enhanced Landing String Assembly offered by the Expro Group that includes such a lubricator valve. Other designs combine rotation and translation of the ball with a separate locking sleeve that is hydraulically driven to lock the ball turning and shifting sleeve in a ball closed position as shown in U.S. Pat. No. 4,522,370. Some valves are of a tubing retrievable style such as Halliburton&#39;s PES® LV4 Lubricator Valve. Lock open sleeves that go through a ball have been proposed in U.S. Pat. No. 4,449,587. Other designs, such as U.S. Pat. No. 6,109,352 used in subsea trees have a rack and pinion drive for a ball and use a remotely operated vehicle (ROV) to power the valve between open and closed positions claiming that either end positioned is a locked position but going on to state that the same ROV simply reverses direction and the valve can reverse direction. 
         [0006]    What is lacking and addressed by the present invention is a more elegant solution to a downhole ball type lubricator valve. One of the features is the ability to translate the ball for the purpose of locking open a ball that normally rotates between open and closed on its own axis. Another feature is a method of manufacturing parts that must be longitudinally split so that they retain the original bore dimension despite the wall removal occasioned by longitudinally splitting the part. Yet another feature is the ability to assemble components to a given overall dimension so as to accurately set preload on biased seats that engage the ball. These and other features of the present invention will be more readily apparent to those skilled in the art from a review of the preferred embodiment and associated drawings that are described below while recognizing that the full scope of the invention is determined by the claims. 
       SUMMARY OF THE INVENTION 
       [0007]    A ball type downhole lubricator valve features a ball rotating on its axis to open or close with control line pressure to an actuating piston. The ball is also shiftable to a locked open position. A cage surrounds the ball and retains opposed seats to it. The cage is made from one piece and tangential holes are drilled and tapped before the piece is longitudinally split with a wire EDM cutting technique. Fasteners to rejoin the cut halves properly space them to the original one piece internal dimension. Auxiliary tools allow determination of spacing of internal components so that a desired spring preload on the seats against the ball can be achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a section view of the entire lubricator valve; 
           [0009]      FIG. 2  is a larger view of the top end of the valve of  FIG. 1 ; 
           [0010]      FIG. 3  is a larger view of the middle of the valve from  FIG. 1  showing the ball open; 
           [0011]      FIG. 4  is an alternate view to  FIG. 3  showing the ball closed; 
           [0012]      FIG. 5  is a larger view of the lower end of the valve of  FIG. 1 ; 
           [0013]      FIG. 6  is a perspective view of the section views shown in  FIGS. 4 and 5 ; 
           [0014]      FIG. 7  shows the top end of the valve in  FIG. 1  during assembly to get proper spacing of internal components; 
           [0015]      FIG. 8  shows the lower end of the valve in  FIG. 1  during assembly to get proper spacing of internal components; 
           [0016]      FIG. 9  is a perspective of the cage that surrounds the ball and is longitudinally split. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0017]      FIG. 1  illustrates the layout of the main components to show their position relative to each other with the ball  10  in the center and in the closed position. Sleeve  12  is above ball  10  and sleeve  14  is below ball  10 . These sleeves respectively form seats  16  and  18  that are held against ball  10  by a cage  20 . Cage  20  is shown in perspective in  FIG. 9 . A slide  22  extends through cage  20  and registers with ball  10  to rotate it between the open and closed position on trunnions  24 . A piston  26  is responsive to control line pressure to reciprocate the slide  22  to operate ball  10 . A lock open assembly  28  is disposed near the top of the tool while the preload adjustment mechanism  30  is located near the opposite end. Using this basic locating of the major components of the valve, the other FIGS. will now be used to bring out additional details and explain the basic operation. 
         [0018]      FIG. 6  can be used to appreciate how the ball  10  is rotated 90 degrees between the closed position shown in  FIG. 6  and the open position shown in section in  FIG. 3 . Piston  26  operates like many pistons known in the art and used in downhole valves. A pair of control lines (not shown) are run from the surface to opposing piston face areas on piston  26  to urge it to move in opposed directions. The piston  26  is secured to the slide  22  for tandem movement. Slide  22  has an upper ring  32  and a lower ring  34  connected by arms  36 , one of which is visible in  FIG. 6 . Looking at  FIG. 9  it can be seen that the cage has longitudinal slots  38  and  40  that accept the arms  36  of slide  22 . Referring to  FIGS. 1 and 6  it can be seen that slide  22  is at the end of its uphole stroke as it has contacted the mandrel  42 . Ball  10  has opposed angled exterior slots  44  one of which is partially in view in  FIG. 6 . The slots  44  are parallel to each other on opposed flats  46  better seen in  FIG. 1 . Flats  46  on ball  10  abut arms  48  and  50  of cage  20  as best seen in  FIGS. 6 and 9 . Holes  52  and  54  accept trunnions  24  that extend into ball  10  to allow it to rotate on its own axis. Cage  22  does not move but when slide  22  is moved by piston  26  the result is rotation of ball  10  on its own axis. This happens because arms  36  have inwardly facing pins (not shown) that register with slots  44  in ball  10  off center from trunnions  24  to induce rotation of ball  10 . 
         [0019]    To better see this movement,  FIGS. 3 and 4  need to be compared.  FIG. 4  shows the ball  10  in a closed position and upper ring  32  close to mandrel  42  but not in contact. This is because a snap ring  56  registers with slot  58  on sleeve  12  to hold the ball  10  in a closed position until enough pressure is exerted on piston  26  to pop the snap ring  56  out of groove  58  until it registers with groove  60  to define the open position of  FIG. 3 . Again, in  FIG. 4  during normal opening and closing of the ball  10 , the only moving part except ball  10  shown in that FIG. is slide  22  with ring  56 .  FIG. 3  shows the fully open position of ball  10  with ring  56  registering with groove  60 . Slide  22  may optionally contact cage  20  at this time.  FIG. 3  also shows piston  26  attached to slide  22  with a fastener  62 . One of the control line connections  64  to operate piston  26  is also shown in  FIG. 3 .  FIG. 3  also shows that sleeves  12  and  14  respectively form flanges  64  and  66  and how the cage  20  retains those flanges together against ball  10 . Seals  16  and  18  respectively are disposed in flanges  64  and  66  for circumferential sealing contact with ball  10  as it rotates between the open and the closed positions of  FIGS. 3 and 4 . 
         [0020]    Looking now at  FIG. 5 , the lower end of the sleeve  14  can be seen as well as another control line connection  68  that is used to urge piston  26  in an opposite direction from pressure applied to connection  64  shown in  FIG. 3 . A bottom sub  70  has a shoulder  72  on which a spring  74  is supported. Spring  74  pushes on ring  76  that is attached to sleeve  14  with a thread  78 . A pin  80  locks the position of ring  76  after that position is initially determined in a procedure that will be explained below. In essence, spring  74  is a preload spring on an assembly that begins with ring  76  and extends to the upper end of the valve shown in  FIG. 2 . 
         [0021]    Referring to  FIG. 2  the lock open feature will be described. Sleeve  12  is ultimately selectively retained by top sub  82 . Shoulder  84  contains fixed ratchet ring  86  against mandrel  42 . Ring  86  has an undercut  88  defining taper  90 . Ring  92  initially sits in undercut  88 . It has ratchet teeth  94  that, in the position of  FIG. 2  are offset from ratchet teeth  96  on ring  86 . Ring  92  bears on retainer ring  98  which, in turn, captures split ring  100  in groove  102  of sleeve  12 . Because of the relation of these parts, sleeve  12  is held down against ball  10  and against the uphole force on sleeve  14  from spring  74  (see  FIG. 5 ). Locking collar  104  has one or more internal grooves  106  for engagement with a tool (not shown) that will ultimately pull the collar  104  uphole. A shear pin  108  initially secures the collar  104  to the sleeve  12 . Sleeve  12  has a groove  110  that eventually registers with tangential pins  112  extending from collar  104 . Collar  104  initially retains ring  92  in undercut  88 . In operation, the collar  104  is pulled up with a tool (not shown) to break the shear pin  108 . As the collar then moves up, tangential pins  112  ride in groove  110  until hitting the top of it at which time the collar  104  moves in tandem with sleeve  12 . In the meantime, collar  104  moves uphole from ring  92  allowing it to collapse inwardly to clear taper  90 . When pins  112  register with the top of groove  110  and the sleeve  12  is moving with collar  104 , ring  100  in groove  102  of sleeve  12  takes with it ring  98  which, in turn now can push ring  92  beyond taper  90  so that ratchet teeth  94  move into engagement with ratchet teeth  96  on ratchet ring  86 . The uphole movement described above continues until sleeve  12  hits a travel stop. This happens in two ways depending on the position of ball  10  when sleeve  12  is being pulled up. If the ball  10  is open, as shown in  FIG. 3 , flange  64  pulls up cage  20  as well as slide  22  which was registered with sleeve  12  at groove  60 . The ball  10  comes up with cage  20  because they are connected at trunnions  24 . The ball  10  does not rotate because there is no relative movement between the slide  22  and the cage  20 . Motion of sleeve  12  stops when ring  32  hits mandrel  42  and that position is held locked by the ratchet teeth engagement of teeth  94  and  96 . On the other hand, if ball  10  is in the closed position of  FIG. 4 , the sleeve  12  will bring up the cage  20  and move it relatively to slide  22 . This happens because at the onset of movement of sleeve  12  the upper ring  32  of slide  22  is already close to mandrel  42  and fairly quickly hits it as the sleeve  12  comes up. Further uphole movement of sleeve  12  pulls the cage  20  relative to the slide  22  which causes the pins in slide  22  to rotate ball  10  to open as they register with slots  44  in ball  10 . When the cage  20  comes against already stopped ring  32  of the slide  22  uphole motion stops and the position is again locked in by engaging teeth  94  and  96 . 
         [0022]    Referring again to  FIG. 2  a spring  114  can optionally be used to push on ring  86  and through the other parts described before downwardly on sleeve  12  which in turn pushes on ball  10  and sleeve  14  which is in turn biased uphole by spring  74  pushing on ring  76  that is attached at thread  78  to sleeve  14 . This assembly keeps the cage  20  in a fixed position for normal operation of the ball  10  and when ring  104  in  FIG. 2  is pulled allows the cage  20  to translate uphole to get the lock open feature with a fully open bore  116  extending through the ball  10  and continuing through sleeves  12  and  14  above and below. As those skilled in the art will appreciate the assembly of parts from shoulder  84  at the upper end to shoulder  118  at the lower end each have their own tolerance and the adjustment available for the position of ring  76  on thread  78  is fairly minimal. As a result, the total dimension of the parts between shoulders  84  and  118  can be determined and the position of ring  76  necessary to give the right preload to the assembled parts also determined before final assembly of top sub  82  and bottom sub  70 .  FIGS. 7 and 8  show this technique. 
         [0023]    Instead of assembling top sub  82  and spring  114  to mandrel  42  an upper gauge  122  is assembled to mandrel  42 . When fully threaded on, a shoulder  124  hits ring  86  in the exact spot that shoulder  84  from top sub  82  would normally engage it. At the same time at the lower end in  FIG. 8  instead of putting on bottom sub  70 , spring  74  or pin  80 , a lower gauge  124  is threaded on to mandrel  42 . Lower gauge  124  has a pair of arms  126  and  128  that respectively have shoulders  130  and  132  that wind up exactly where shoulder  118  would be when bottom sub  70  is screwed on. Because of the open gaps between arms  126  and  128  there is access to adjustment ring  76  and it can be moved up or down on thread  78  as long as pin  80  is not assembled. Ring  76  is turned to bottom on shoulders  130  and  132  and then raised by rotation enough to allow an opening  134  to align with a recess  136  (see  FIG. 5 ) so that ring  76  has its position fixed as close as possible to shoulder  118  when the bottom sub  70  is assembled with spring  74 . Similarly, the upper gauge  122  ( FIG. 7 ) is first removed and replaced with top sub  82  and spring  114  ( FIG. 2 ). When the bottom sub  70  and spring  74  get screwed on, spring  74  will have the needed preload since despite the accumulation of tolerances of all the assembled parts the actual surface of ring  76  is determined as it related to spring  74  for the desired preload. 
         [0024]    Referring now to  FIG. 9  the cage  20  is illustrated as fully assembled. Since it needs to straddle ball  10  and flanges  64  and  66  ( FIG. 3 ) it needs to be made into two pieces. The technique for making this piece or, for that matter, other pieces that need to be made in two pieces to be assembled over yet other pieces, is to make a longitudinal cut  140 . Before doing that, all the machining shown in  FIG. 9  is done including bores  142  and  144  on one side and similar bores on the other side (not visible) that go though where longitudinal cut  140  will be made. Again, before the cut is made, the bores  142  and  144  are tapped. Thereafter the cut  140  is made by a wire EDM technique. This known technique removes a part of the wall away where the cut is made. Thus, after the cut halves are pushed together, their inside diameter  146  will be smaller than it was before the cut. However, the pitch of the tapped thread and the matching thread on the studs  148  and  150  when screwed in to bridge the cut  140  will, because of the thread pitch separate the halves at cut  140  just enough to compensate for the amount of wall removed during the cut so that when fully assembled the original one piece diameter  146  that was there before the cut is again present. While the wire EDM removes only a few thousandths of an inch out of the wall to make the longitudinal cut the result is still a change in the internal bore dimension. This technique of drilling and tapping before a longitudinal cut with wire EDM allows the original bore dimension to be regained while holding the cut halves together. 
         [0025]    Those skilled in the art will recognize that the ball type lubricator valve can be normally operated with control line pressure that moves piston  26  in opposed directions to rotate ball  10  on its own axis for 90 degrees to the open and closed positions. An indexing feature holds the open and closed positions when they are attained. The valve can be locked open from either the open position or the closed position by freeing the upper sleeve  12  to move and lifting it until it ratchet locks with the ball  10  in the open position while maintaining a full bore through the valve. While a ratchet lock is illustrated other locking devices such as dog through windows, collets or other equivalent devices are also contemplated. It should be noted that translation of ball  10  is only employed when attempting to lock it open. It should be noted that parts can be reconfigured to alternatively allow the ball  10  to be locked closed as an alternative. 
         [0026]    Yet another feature of the lubricator valve is the preloading of the internal components and the ability to gauge the dimension of the internal components before mounting the top and bottom subs with the spring or springs that provide the preload so the proper amount of preload can be applied. Yet another feature is a way of making longitudinally split parts so that they retain their original internal dimension despite removal of a part of the wall for a cutting operation using the drill and tap technique before longitudinal cutting by wire EDM and then regaining near the original spacing in the joined halves relying on the pitch of the tapped thread and the fastener inserted in the bore and spanning the longitudinal cut. In this particular tool the cage  20  and slide  22  can be made with this technique. The technique has many other applications for longitudinally split parts with internal bores that must be maintained despite wall removal from a cutting process like wire EDM. 
         [0027]    While the preferred embodiment has been set forth above, those skilled in art will appreciate that the scope of the invention is significantly broader and as outlined in the claims which appear below.