Abstract:
A lock system works in combination with a mandrel to allow selective operation and disabling of a downhole tool. In the specific situation of a Smart Collet® the tool is locked from being able to find support when engaged to a mating profile as the tool is moved between landing locations. A lower housing features an external dog that in response to rotation takes with it a collet ring with circumferentially oriented fingers. An outer housing cams the collet heads into a respective groove in the mandrel. Reversal of such relative rotation between the upper and lower housings allows the collet heads to spring out of the mandrel groove for the unlocked position. The lock is adapted for use in a variety of tools. The rotation to unlock and then lock is accomplished by dog interaction with shaped internal profiles in a surrounding tubular assembly at strategic locations where needed.

Description:
FIELD OF THE INVENTION 
       [0001]    The field of the invention is a selectively operated lock for a downhole tool and more particularly a selective lock for a Smart® Collet when used in multiple zone completions. 
       BACKGROUND OF THE INVENTION 
       [0002]    The details of the assembly and operation of Smart® Collets is described in detail in U.S. Pat. No. 6,382,319 and 6,464,006. In essence the collet lands at predetermined support locations in an outer screen assembly and is part of an inner string. For example, in U.S. Pat. No. 6,382,319  FIG. 1  the support locations are  36 ,  37  and  38  and their spacing is known as a single zone is being treated. However in multiple zone completions the spacing of the support locations intended to operate with the Smart® Collet may be unknown or the large spacing between zones with the potential of other tools being in the assembly that present potential unintended support locations for the Smart® Collet present problems to surface personnel in determining if the inner string assembly in a gravel pack is properly aligned so that gravel delivered through the frac port in the inner string will properly cross over to the outer annular space of the zone that needs the gravel packing. What is needed as provided by the present invention is a way to selectively prevent the Smart® Collet from supporting any load until it comes in proximity of the shoulder on which it is intended that it will support a load. At this point the lock is defeated to allow the Smart® Collet to function normally for proper crossover support at the desired zone to selectively circulate or squeeze or reverse out in the known manner as described in the aforementioned patents. While the preferred application will be described as being for a Smart® Collet in a multi-zone gravel packing operation, those skilled in the art will appreciate that there are broader applications for locks that selectively unlock and reset to respectively unlock and lock an associated tool for multiple operations at spaced subterranean locations. 
         [0003]    Sleeves have been used for location and orientation of keys to insure that a given collet system only latches at a desired profile location as described in US Publication 2003/0173089 A1. In a different application a protective sleeve reduces the drift diameter to protect a release sleeve from catching a hold of the release sleeve inadvertently and moving it. A release tool is inserted through the release sleeve and into the protective sleeve inside diameter. The protective sleeve has an inner spline for the release tool to be able to get past the release sleeve and get a grip on the release sleeve to shift it. This device is described in U.S. application Ser. No. 13/142,552. 
         [0004]    Downhole swivels involve a locking and unlocking feature for selective tandem or relative rotation of components that is accomplished with longitudinal component shifting to selectively engage a second pair of splines to another set of splines that are already meshed using a common shaft. Swivels of this type are shown in U.S. Pat. No. RE41, 759 and in a different application in U.S. Pat. No. 7,828,064 and 8,118,102. 
         [0005]    What is needed and provided by the present invention is a simple lock and unlock feature for a subterranean tool that is located on a string delivering the tool that selectively allows the tool to operate as intended at predetermined locations and then locks the tool against operating as the tool is moved away from the desired location of operation. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined by the appended claims. 
       SUMMARY OF THE INVENTION 
       [0006]    A lock system works in combination with a mandrel to allow selective operation and disabling of a downhole tool. In the specific situation of a Smart Collet® the tool is locked from being able to find support when engaged to a mating profile as the tool is moved between landing locations. A lower housing features an external dog that in response to rotation takes with it a collet ring with circumferentially oriented fingers. An outer housing cams the collet heads into a respective groove in the mandrel. Reversal of such relative rotation between the upper and lower housings allows the collet heads to spring out of the mandrel groove for the unlocked position. The lock is adapted for use in a variety of tools. The rotation to unlock and then lock is accomplished by dog interaction with shaped internal profiles in a surrounding tubular assembly at strategic locations where needed. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]      FIG. 1  is a section view of a known Smart® Collet with the selective lock feature shown at the right end; 
           [0008]      FIG. 2  is an enlarged view of the lock feature at the right end of  FIG. 1 ; 
           [0009]      FIG. 3  shows a two zone gravel packing application of the lock system of the present invention with the Smart® Collet in the locked position; 
           [0010]      FIG. 4  is the view of  FIG. 3  with the Smart® Collet unlocked and supporting a crossover in a profile so that the frac port aligns with the port above the screens to the outer annulus of the lower zone; 
           [0011]      FIG. 5  is the view of  FIG. 4  after the lower zone is completed with the Smart® Collet locked for movement to the next zone uphole; 
           [0012]      FIG. 6  is a perspective view of the upper housing seen through the lower lousing; 
           [0013]      FIG. 7  is a perspective view of the collet type lock ring; 
           [0014]      FIG. 8  is a perspective view of the collet type lock ring in the unlocked position; 
           [0015]      FIG. 9  is the view of  FIG. 8  with the collet type lock ring in the locked position; 
           [0016]      FIG. 10  is an interior view of a part of the outer housing adjacent an associated landing location for a Smart Collet® that selectively allows unlocking and relocking; and 
           [0017]      FIG. 11  is a section view showing the unlocked position of the collet type lock ring with respect to an adjacent mandrel groove. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    Referring to  FIG. 1  the Smart® Collet  10  is of a type known in the art and described in detail in U.S. Pat. No. 6,382,319 and 6,464,006. In operation, greatly simplified, the collet assembly is a movable member  10  that moves radially and relatively axially with respect to the mandrel  12  so that the collet assembly  10  can snap into profile  14  in the surrounding tubular  16 . Once there is such engagement the mandrel  12  can be axially manipulated with respect to the collet assembly  10  now supported in profile  14 . This relative axial motion can place support  18  in line with inner ring  20  on the collet assembly  10  to lock the collet assembly  10  in the profile  14 . There are generally several such profiles  14  in spaced locations for a given zone to gravel pack to support the circulate, squeeze and reverse out positions of the crossover (not shown) that supports the collet assembly  10  through the mandrel  12  support  18  misaligned with ring  20  to then allow the collet assembly  10  to radially collapse and move out of the profile  14 . The lock assembly  22  is supported by mandrel  12  and is designed to selectively permit or prevent relative axial movement between the mandrel  12  and the collet assembly  10 . In the locked position the support  18  is held offset to ring  20  so that the collet assembly  10  cannot find support in any profile such as  14 . When lock assembly  22  is released, the collet assembly  10  works as a known Smart® Collet. 
         [0019]    An assembly for two zones  24  and  26  is illustrated in  FIG. 3 . Zone  24  is between packers  28  and  30  and zone  26  is between packers  30  and  32 . Screens  34  are in zone  24  and screens  36  are in zone  26 . The screens  34  and  36  respectively have openings  38  and  40  above to allow gravel slurry or other fluids to pass into the outer annulus in the borehole that reaches the zones  24  and  26  by going through the outer assembly  50 . The collet assembly  10  engages profile  42  in zone  24  or profile  44  in zone  26  in a known manner.  FIG. 3  shows profile  46  for example in section and  FIG. 4  shows the inside view showing the adjacent and alternating peaks  52  and valleys  54 . Preferably there is a constant pitch to the pattern. The patterns at profiles  46  and  48  can be identical or the pitch on one can be the reverse of the pitch on the other. 
         [0020]    When relative axial movement is permitted between the mandrel  12  and the collet assembly  10  it allows normal Smart® Collet operation in zone  24  just as the collet assembly  10  comes into the vicinity of the support locations  42  in zone  24 . This normal operation is shown illustratively in  FIG. 4  for the lower zone  26  which would normally be treated first. The same process occurs in zone  24 .  FIG. 5  shows the inner string of mandrel  12 , collet assembly  10  and lock assembly  22  moving sufficiently to lock the Smart Collet® until zone  24  is reached. 
         [0021]    The lock assembly  22  serves to permit or prevent the support  18  to align with the ring  20  so that the Smart Collet®  10  selectively enabled to latch into a given profile or just snaps in and right back out due to the inability of support  18  to get aligned with ring  20 . It is this relative movement that the locking assembly permits or prevents. The locking assembly  22  is selectively movable with respect to a mandrel  100 . Mandrel  100  has a groove or grooves  102  as best seen in  FIG. 11 . A collet ring  104  is seen in section in  FIG. 11  and in perspective in  FIG. 7 . There is a base ring structure  106  that has circumferential wire EDM cuts  108  and  110  made parallel to each other with a collet head  112  at the free end so that the heads  112  at the end of each finger  114  can flex in a radial direction either toward or away from a corresponding groove  102  in the mandrel  100 . The is a leading ramp  114  on each collet head  112  that interacts with ramp  116  on top housing  118  as best seen in  FIG. 7 . Rotation of mandrel  100  is in tandem with rotation of the lower housing  120  seen in  FIG. 6 . Ring  104  has alternating peaks  122  and valleys  124  into which the top of the lower housing  120  mesh. Lower housing  120  has a radially biased dog  126  that has end ramps  128  and  130  near the top end  132  as well as opposed side ramp pairs  134  and  136 . The biasing is by one or more springs that are not shown and are between the dog  126  and the sleeve  138  that supports dog  126 . Thus rotational force acting on dog  126  will rotate the lower housing  120  and take with it the ring  104 . As a result ramp  114  will ride on ramp  116  and then on the inside diameter  140  of the upper housing  118  so that the heads  112  are radially part within the ring structure  106  and part within groove  102  for the axially locked position of  FIG. 9 . Either rotating the ring  104  in the opposite direction or further in the same direction will allow the heads  112  to move radially outwardly into an adjacent slot  142  that has the shape of a head  112  allowing the spring in the fingers  114  to snap the heads  112  into slot  142  for the unlocked position. Note that the upper housing  118  and the lower housing  120  are secured together at  142  as seen in  FIG. 11  but can relatively rotate about the snap ring  144 . Thus with the heads  112  in groove  102  the upper housing  118  and lower housing  120  are in such a position the Smart Collet® cannot find support by alignment of  18  with  20  even if collet  10  snaps into profiles  42  or  44 . However, the mandrel  100  with the housings  118  and  120  can still move relative to the outer assembly  50  so that the profiles in  FIG. 10  that are part of the outer assembly come into play. 
         [0022]      FIG. 10  shows one way to rotate heads  112  between the locked position of  FIG. 9  and the unlocked position of  FIG. 8 . Again, in the unlocked position mandrel  100  can move enough to align  18  with  20  so that the collet  10  can find support in a profile such as  42  or  44 . In the locked position of  FIGS. 9   18  and  20  can&#39;t align so that the collet  10  just snaps in and right out of profiles such as  42  and  44 . In either case, the mandrel  110  can move axially with housings  118  and  120  so that dogs  126  and  146  can interact with internal profiles  148  and  150  that are part of the outer assembly  50 . Profile  148  has two components  152  and  154  that interact with dogs  126  and  146 . 
         [0023]    Mandrel  100  movement in the direction of arrow  156  acts only to compress the dogs  126  and  146  radially inwardly against an opposing spring bias from internal springs to those dogs that are not shown. In essence the top tapers  128  and  158  of dogs  126  and  146  respectively facilitate the radially inward movement of both dogs past blunt surface transitions  160 ,  162  and  164 . Whether the tool was locked as in  FIG. 9  or unlocked as in  FIG. 8  does not change with movement of dogs  126  and  146  in the direction of arrow  156 . After dog  146  passes lower point  166  and snaps radially out the movement of the mandrel  100  is reversed to the direction of arrow  168 . As movement continues the dog  146  is pushed left or right by point  166 . Further movement in the direction of arrow  168  by the mandrel  100  brings dog  146  into wide slot  168  as dog  126  reaches the point  166  and is deflected left or right into alignment with wide slot  168 . At point  170  the dog  146  will be on one side of point  170  and dog  126  will be on the other side of the barrier  172 . Then ramp  174  relatively rotates the dogs  126  and  146  so that the unlocked orientation of  FIG. 8  is accomplished. At that point the collet  10  can find profile such as  42  and lock to it as  18  lines up with  20 . When the operation there is completed the mandrel  100  can be further picked up and the direction of relative rotation that unlocked is reversed so that the locked position of  FIG. 9  is assumed. After that the collet  10  can be safely moved to the next profile where another structure such as  FIG. 10  is to be found and movement through profiles  152  and then  154  will again resume the unlocked position of  FIG. 8  so that the collet  10  can be landed and supported in the normal manner. 
         [0024]    Those skilled in the art will appreciate that there are variations that could be employed in the number of mandrel grooves  102  and collets oriented circumferentially on the ring  104  for engagement. Movement between the locked and unlocked positions can be with rotation in a single direction or rotation in equal measure in opposed directions. The profiles in  FIG. 10  induce relative rotation between the lower housing  120  and ring  104  on one hand and the upper housing  118  on the other hand so that the circumferentially oriented heads  112  get pushed into the grooves  102  for the locked position while reverse relative rotation allows the heads  112  to snap out into grooves  176  as shown in  FIG. 8  for the unlocked position. While the preferred application is for a collet such as  10  the described locking and unlocking mechanism can be used in a variety of downhole applications where certain relative movements are to be prevented at a desired time and then subsequently enabled. In the preferred embodiment the locked position of  FIG. 9  interacts with the Smart Collet® components to prevent aligning  18  with  20  so that the collet  10  can be supported. In the unlocked position of  FIG. 8  different mandrel movement becomes possible and the collet  10  can be supported with  18  aligning with  20  to selectively lock the collet  10  in the known manner. 
         [0025]    Those skilled in the art will appreciate that the invention seeks to keep a tool in a locked position when being moved past areas where premature operation is not desirable. The lock system can unlock and relock to allow normal tool operation in a desired zone while preventing operation for any reason when away from desired zones of operation. It is particularly adept at dealing with multiple completion zones where a crossover has to take several positions in a particular zone to accomplish the circulation, squeeze and/or reverse out positions. Mere axial movement is automatically converted to rotation that selectively locks or unlocks the associated tool, which in the preferred embodiment is the Smart® Collet. The benefit of the present invention is the simplicity and the automatic nature of the operation so that that a problem of the Smart® Collet getting a support where it is not desired are eliminated. In essence the lock assembly  22  in a movement of the inner string with the Smart® Collet respectively enables normal operation and then disables normal operation by locking the collet assembly  10  to the mandrel  12  to prevent unintended operation at anywhere but the intended support locations such as at multiple zones  24  and  26 . Those zones can be far apart with several radial surfaces in between where the Smart® Collet could otherwise be engaged to find support for the inner string but for the presence of the lock assembly  22  of the present invention. 
         [0026]    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: