Patent Publication Number: US-2005126775-A1

Title: Hydraulic release running tool

Description:
FIELD OF INVENTION  
      The invention relates to hydraulic release running tools for setting rotatable liner hangers; and more particularly to running tools having a secondary mechanical release and backlash relief.  
     BACKGROUND OF THE INVENTION  
      Running tools are used in combination with liner hangers in wellbore drilling and completion operations. Following drilling of at least a segment of a wellbore, casing is positioned into the open hole and cemented into place. Drilling is continued below the cemented casing to extend the depth of the wellbore. At least a second length of smaller diameter casing is lowered into the extended wellbore on a tubing string equipped with a releasable running tool and a liner hanger. Mechanical release running tools are often used for vertical wellbores. Hydraulic running tools are often preferred for high angle and horizontal wells due to increased difficulty in relying on mechanical manipulation to release the running tool from the liner hanger once properly located.  
      Running tools are required to securely support the liner yet also be reliably releasable. The conditions of liner installation introduce non-trivial challenges for a running tool. To install liner, a liner hanger assembly of a liner hanger and a considerable weight of depending liner is hung from a releasable running tool. The running tool is run in downhole until the liner hanger is adjacent a distal end of the last cemented casing. Liner hanger slips are actuated to grip the walls of the existing casing and support the substantial weight of the depending liner until such time as the new liner can be cemented into place. This is repeated as often as necessary, each liner then becoming the casing supporting subsequent liners. It is also known to rotate the liner, not only during insertion into the wellbore, but also after setting of the liner hanger slips. Depending upon the circumstances, it may be advantageous to rotate the liner during cementing such as to ensure a uniform distribution of cement in the casing annulus as well as proper displacement of the drilling mud, without channeling of the cement through the mud. The running tool is required to enable rotation without releasing prematurely.  
      Once located downhole, pressure in the bore of the tubing string is increased to actuate the liner hanger and set the slips to the casing. The weight of the liner is now hanging from the liner hanger and distal end of the casing. Fluid communication is established from the tubing string to the wellbore and a pre-determined volume of cement is pumped out through a float shoe. The liner may be rotated through rotation of the tubing string and running tool. Drilling fluid is displaced up a casing annulus until the cement finally reaches the liner hanger. Cementing is then stopped, after which the running tool is released from the liner hanger and removed from the well.  
      To avoid catastrophic circumstances should the running tool fail to release by the completion of cementing, it is preferably to pre-release the running tool from the liner hanger prior to cementing. Accordingly, the running tool must not release prematurely such as during running and setting of the liner hanger nor during preparation for cementing. Further, the running tool must resist significant backlash forces which can result from the rotating liner installation. Additionally, in the case of hydraulic running tools, should the hydraulic release fail, it is preferably to have some backup means for releasing the tool from the liner hanger.  
     SUMMARY OF THE INVENTION  
      In one embodiment of the invention, apparatus is provided for hydraulic release of a running tool from a downhole tool such as a liner hanger. In another embodiment, secondary apparatus is provided for mechanical release actuation of components of the hydraulic release as a backup. In yet another embodiment, a latch for releasably supporting a mandrel in a tubular tool is provided In yet another embodiment, a clutch is provided and in another embodiment the clutch is integrated with a running tool for avoiding accidental actuation of the secondary mechanical release apparatus. In an embodiment of the clutch, a ratchet is provided.  
      Accordingly, in one broad aspect of the invention, a running tool is adapted to releasably support a downhole tool comprising: a hydraulic release, a mandrel having a bore and a locking cylinder movable axially over the mandrel and forming a piston annulus therebetween, a port being formed between the bore and the piston annulus, the locking cylinder having an uphole end; a piston in the piston annulus and whose movement is axially delimited between an uphole stop on the mandrel and a downhole stop on the locking cylinder sleeve, the port being positioned axially between the uphole stop and the piston; a latch cage positioned uphole of the locking cylinder and being movable axially on the mandrel between an engaged position and a disengaged position, the latch cage having two or more latch segments which are supported axially and movable radially so that when the latch cage is in the engaged position, the latch segments are supported in a radially extended position to engage with and axially support the downhole tool, and in the disengaged position, the latch segments are released to a radially recessed position to disengage from the downhole tool; and two or more latch shoulders positioned downhole of the latch cage for axially supporting the latch cage in the engaged position, the latch shoulders being temporarily retained radially to the mandrel by the uphole end of the locking cylinder, so that pressure applied at the port, hydraulically drives the piston downhole to engage the downhole stop, moving the uphole end of the locking cylinder downhole to release the latch shoulders from the mandrel and permitting the latch cage to move axially to the disengaged position for releasing the latch segments from the downhole tool.  
      Preferably, in another aspect of the invention, a secondary mechanical release is provided further comprising: an uphole drive housing fit about the mandrel and uphole from the latch cage wherein the drive housing is co-rotatable with the mandrel and has a drive face adapted for rotational drive coupling with the downhole tool, the mandrel being releasably supported on the drive housing; and means for releasing the mandrel for axial movement through the drive housing and for manipulation through the latch cage so as to shift the latch cage and latch segments relatively uphole to the disengaged position. Preferably, a temporary axial restraint, such as circumferentially space profiles between the drive housing and the mandrel which are alternatively selected using a J-slot, exists between the latch cage and the mandrel. The temporary axial restraint is overcome by relative movement of the downhole tool and the mandrel.  
      Accordingly, in yet another aspect of the invention, a rotational clutch is provided between the mandrel and the uphole drive housing wherein a ratchet annulus is formed between the mandrel and the uphole drive housing, the tool further comprising: an external mandrel spline extending radially outwards from the mandrel into the ratchet annulus; an internal housing spline extending radially inwards from the uphole drive housing into the ratchet annulus; and a barrel ratchet residing in the ratchet annulus and having internal teeth extending radially inward from a body and external teeth extending radially outward from the body, the body being flexible for enabling the internal teeth and external teeth to move radially in the annulus and alternate between locking the mandrel spline and housing spline for co-rotation in a driving direction and releasing the mandrel spline and housing spline in a ratcheting direction, wherein the body of the barrel ratchet flexes to lock the mandrel spline and housing spline for co-rotation in a driving direction, and the barrel ratchet flexes to separate at least one of the barrel ratchet&#39;s internal or external teeth from the mandrel spine or housing spline respectively to release the mandrel spline and housing spline and enable relative rotation.  
      In another broad aspect of the invention, a ratchet for enabling uni-directional torque comprises: a mandrel and a housing forming an annulus therebetween, the mandrel having an external spline extending into the annulus and the housing having an internal spline extending into the annulus; and a barrel ratchet residing in the ratchet annulus and having internal teeth extending radially inward from a body and external teeth extending radially outward from the body, the body being flexible for enabling the internal teeth and external teeth to move radially in the annulus and alternate between locking the mandrel spline and housing spline for co-rotation in a driving direction and releasing the mandrel spline and housing spline in a ratcheting direction, wherein the body of the barrel ratchet flexes to lock the mandrel spline and housing spline for co-rotation in a driving direction, and the barrel ratchet flexes to separate at least one of the barrel ratchet&#39;s internal or external teeth from the mandrel spine or housing spline respectively to release the mandrel spline and housing spline and enable relative rotation. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1   a  is a one quarter section elevation view of a hydraulic running tool having secondary mechanical release and a barrel ratchet clutch accordingly to an embodiment of the invention;  
       FIG. 1   b  is a cross-section of the tool of  FIG. 1   a  along lines  1   b - 1   b  illustrating the barrel ratchet-type clutch between the mandrel and the upper drive housing;  
       FIGS. 2   a - 7  are cross-sectional views of an embodiment of the running tool according to  FIG. 1   a  illustrating latches and hydraulic release apparatus. Each view is shown in the context of and relative to a liner hanger so as to illustrate stages of operation, more particularly:  
       FIG. 2   a  illustrates the running tool before hydraulic release;  
       FIG. 2   b  is a closer view of the downhole latch housing;  
       FIG. 2   c  is a closer view of the uphole housing;  
       FIG. 2   d  is a cross-section of the tool according to  FIG. 2   a  taken along lines  2   d - 2   d  and illustrating the latch segments in a radially outward latched position;  
       FIG. 3  illustrates hydraulic actuation for release of the latch cage and latch segments;  
       FIG. 4   a  illustrates pickup of the mandrel for release of the latches from the liner hanger;  
       FIG. 4   b  is a cross-section of the tool according to  FIG. 4   a  taken along lines  4   b - 4   b  and illustrating the latch segments in a radially inward un-latched position;  
       FIG. 5  illustrates the mandrel free from the liner hanger for confirming released pick-up weight;  
       FIG. 6  illustrates set-down for rotational coupling with the liner hanger while released therefrom;  
       FIG. 7  illustrates release and retrieval of the running tool;  
       FIGS. 8   a - 14  are cross-sectional views illustrating another embodiment of the running tool according to  FIG. 1   a  showing mechanical release of the tool. Again, each view is shown relative to a liner hanger so as to illustrate various stages of operation:  
       FIG. 8   a  illustrates the running tool before mechanical release;  
       FIG. 8   b  illustrates is a cross-section of the tool according to  FIG. 8   a  taken along lines  8   b - 8   b  and illustrating the clutch ring and J-Slot in a load supporting position for supporting the mandrel from the upper drive housing;  
       FIG. 9   a  illustrates a ¼ turn left hand (LH) rotation of the mandrel for axial manipulation of the mandrel for enabling release of the latch segments;  
       FIG. 9   b  illustrates is a cross-section of the tool according to  FIG. 9   a  taken along lines  9   b - 9   b  and illustrating the clutch ring and J-Slot in a disengaged position with shear screws sheared for enabling mechanical release of the latch shoulders and latch segments;  
       FIG. 10  illustrates set down of the mandrel for shifting the mandrel downhole relative to the latch cage, releasing the latch segments;  
       FIG. 11  illustrates further set down of the mandrel, bottoming the range of motion of the upper drive housing and clutch ring, for ensuring release of the latch segments;  
       FIG. 12  illustrates pickup of the mandrel free from the liner hanger for confirming release of the latch segments through reduced pick-up weight;  
       FIG. 13  illustrates set-down for right hand (RH) rotational coupling with the liner hanger while remaining axially released therefrom;  
       FIG. 14  illustrates retrieval of the running tool from the liner hanger;  
       FIGS. 15   a - 17   b  are cross-sectional partial side views and end views respectively of the mandrel with integrated mandrel spline, the barrel ratchet and the upper drive housing respectively, more particularly  
       FIGS. 15   a  and  15   b  are cross-sectional partial side views and end views respectively of the mandrel with integrated mandrel spline;  
       FIGS. 16   a  and  16   b  are cross-sectional side and end views of the barrel ratchet with internal and external teeth;  
       FIGS. 17   a  and  17   b  are cross-sectional side and end views of the upper housing drive nut with an integrated housing spline;  
       FIGS. 18   a  and  18   b  illustrate two isometric views of an embodiment of the barrel ratchet having with internal and external teeth illustrating the alternating end axially-slotted cylindrical body;  
       FIGS. 19   a  and  19   b  are cross-sectional end views of the clutch comprising the mandrel spline, barrel ratchet and housing spline coupled to first illustrate RH rotation of the mandrel in a locked drivable position to enable the mandrel to rotate the housing ( FIG. 19   a ), and secondly to illustrate left hand (LH) rotation of the mandrel in a ratcheting released position ( FIG. 19   b ) respectively;  
       FIGS. 20   a - 20   c  are partial cross-sectional end views of the clutch operations,  FIG. 20   a  corresponds to  FIG. 19   a ,  FIG. 20   b  corresponds to  FIG. 19   b  and  FIG. 20   c  illustrates a rest position with the flexibility range of the barrel ratchet body radial motion being evident; and  
       FIGS. 21   a  and  21   b  are partial cross-sectional end views of the clutch operations using an optional embodiment corresponding to the operations illustrated in  FIGS. 20   a  and  20   b , wherein the orientation of the housing spline and external teeth are oriented opposite to that of the embodiment of  FIGS. 19   a , 20   a  and  19   b , 20   b  respectively. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Running Tool  
      In one embodiment of the invention, and shown generally in  FIG. 1   a , running tool  5  is provided featuring hydraulic release with optional backup mechanical release and a uni-directional torque clutch that provides premature release protection by dampening anti-backlash and over-rotation as shown in  FIG. 1   b . Such features are applied in downhole operational circumstances, including for releasable coupling with and running in and release of a liner hanger (not shown). Running tools incorporating the present invention can be applied for releasable connection tubular portions of other downhole tools and to greatest effect with tools that would be rotated and released and preferably rotated once released. The preferred embodiment is described in the context of running in, release and rotation, such as during the process of cementing of a liner hanger.  
      The running tool  5 , liner hanger and depending new liner are run downhole to a setting depth, typically with the liner hanger adjacent the downhole end of the previous casing. The liner hanger is hydraulically set to hang from the previous casing. Prior to commencing cementing of the new liner, it is preferable to ensure the running tool  5  is released from the liner hanger. The running tool  5  is hydraulically released as described herein and in another embodiment of the present invention, should the hydraulic release fail, the running tool  5  is released using an integrated backup mechanical release. Release can be confirmed with a pickup of the string and running tool. Once released the running tool  5  of the present invention further enables rotation of the running tool  5  for drivably rotating the set liner hanger and new liner while cement is circulated.  
      Turning to one embodiment of the hydraulic release running tool  5 , and with reference to  FIGS. 1   a ,  2   a  and  2   b , a running tool  5  generally comprises a mandrel  10  suspended from a drill string (not shown). For convenience, figures represented in landscape format are oriented with uphole to the left.  
      The liner hanger  13  hangs from the mandrel  10  through a releasable latch between the mandrel  10  and the bore of the liner hanger  13 . The mandrel  10  is prevented from pushing through the liner hanger  13  using an uphole drive housing  11  which engages an uphole end of the liner hanger  13 .  
      More particularly, the mandrel  10  extends through an uphole drive housing  11  and through a downhole housing  12 . The drive housing  11  enables co-rotation of the mandrel  12  and the liner hanger  13  (a tubular uphole end of a liner hanger assembly illustrated in  FIG. 2   a ). The downhole housing  12  releaseably connects the liner hanger  13  and the mandrel  10 .  
      More specifically with reference to  FIGS. 2   a  and  2   b , the uphole drive housing  11  comprises a locking cylinder  20  having a drive face  21  at a downhole end which is profiled for drivable connection with a complementary drive face  22  at an uphole end of the liner hanger  13 . The sleeve  20  is biased axially downhole using a spring  23  for urging the drive face  21  into engagement with the liner hanger  13 . Preferably, the complementary profiles of the drive housing and liner hanger drive faces  21 , 22  are castellations as one means for enabling a drivable rotational coupling.  
      The drive housing  11  is co-rotatable with the mandrel  10  for driving the liner hanger through a non-circular interface  24  which prevents relative rotation of the sleeve  20  and mandrel  10  yet enables spring-loaded axial movement of the sleeve  20  thereon. Preferably, means for co-rotating the drive housing  11  with the mandrel  10  comprises a clutch  25  as described below in greater detail in the context of a mechanical release apparatus for the tool  5 .  
      The downhole housing  12  comprises a latch cage  12   a  and a hydraulic housing  12   b , both of which are sized to fit into an uphole bore of the liner hanger  13 . A plurality of circumferentially-spaced latch segments  30  are operable through ports  31  in the latch cage  12   a  for alternately engaging and disengaging a latch profile  32  with a cooperating and receiving profile  33  in the uphole bore of the liner hanger or other intermediate tubular, uphole of the liner hanger. The latch segments  30  are biased inwardly toward the mandrel  10  by a spring  34 . The latch cage  12   a  is temporarily restrained to the mandrel  10  using shear screws  29 . The latch segments  30  are releasable from the liner hanger  13  under either hydraulic or mechanical release operations.  
      The latch segments  30  are normally supported radially from the mandrel  10  and axially in the engaged position for running in due to the axial positioning of the latch cage  12   a . The weight of the liner hanger  13  typically hangs from the latch segments  30  during running in. Further, once the liner hanger  13  is set, then set down weight on the mandrel  10  is normally supported upon the liner hanger  13  through the uphole housing and drive faces.  
      Each latch segment  30  is supported axially in the latch cage  12   a . Axial movement of the latch segments  30  alternately position the latch segments in a radially recessed position with respect to the mandrel  10  or a radially extended position. Control of the axial position of the cage  12   a  controls whether the latch segments are in the engaged ( FIG. 2   d ) or disengaged position ( FIG. 4   b ).  
      One embodiment enabling alternate recessed and extending positions of the latch segments is to initially support the latch segments  30  radially outward in an engaged position on ribs  40  extending radially from the mandrel  10  and to subsequently release the latch segments when misaligned from the ribs  40 . Greater radial movement is further aided by fitting the latch segments  30  with corresponding ribs  41  extending radially inwardly. When the mandrel ribs  40  and latch segment ribs  41  are axially aligned, the latch segment  30  is positioned at its maximal radial extent and is in the engaged position. The ribs  40  and  41  have a limited axial extent. When the ribs  40 , 41  are axially misaligned either uphole or downhole, the latch segments  30  can retract radially to the mandrel  10  to a minimal radial extent and are in the disengaged position.  
      The latch cage  12   a  is primarily supported against downhole movement by latch shoulders  35  releasably engaged with and supported on the mandrel  10 . The latch shoulders  35  engage the mandrel  10  through an annular profile  36  which engages corresponding annular profile  37  formed in the mandrel. As long as the latch shoulders  35  are retained radially inwards against the mandrel  10 , the latch shoulders  35  are capable of supporting the entire hanging weight. The hydraulic housing  12   b  aids in retaining the latch shoulders  35  against the mandrel  10 . Relative movement of the mandrel  10  and the latch cage  12   a  either uphole or downhole releases the latch segments  30  from the liner hanger  13 .  
      In one embodiment, this relative axial movement is through hydraulic release of support from beneath the latch cages  12   a  through hydraulic manipulation of the downhole housing  12   b  resulting in release and removal of the latch shoulders  35  for enabling downhole movement of the mandrel  10  relative to the latch cage  12   a.    
      Alternatively, relative axial movement of the latch cage  12   a  and mandrel  10  is through manipulation of the uphole housing  11  for freeing the mandrel  10  and enabling forcible movement of the mandrel relative to the latch cage  12   a  during actuation of the backup mechanical release. As shown in  FIGS. 2   a , 2   c , normally downhole movement of the uphole housing  11  is arrested by a resting engagement of the uphole housing  11  onto a portion of the subject tool, in this case the drive face  22  of the liner hanger  13 . The mandrel  10  has limited capability for axial uphole movement relative to the uphole housing  11  due to clutch ring  70  which is releasably restrained to the mandrel  10  and to the uphole housing  11 . The clutch ring  70  has circumferentially segmented and radially-inward profiles  71  which mate with co-operating a circumferentially segmented annular profiles  72  on the mandrel which are releasable upon indexed, relative rotation. The clutch ring has radial dogs  73  which are rotationally restrained in axial slots  74  in the uphole housing  11  with a dog and spline arrangement which permits axial movement. The axial slots  74  have a stop  75  which limit the axial extent of the movement of the clutch ring&#39;s dogs  73 .  
      Hydraulic Release  
      More specifically, and with reference to  FIGS. 2   a - 2   d  and  FIGS. 3-7 , the hydraulic release aspects of the running tool  5  are illustrated. The hydraulic release embodiment of the present invention implements means for release of support from beneath the latch cage  12   a , enabling axial misalignment of the mandrel ribs  40  and latch segment ribs  41  for permitting the latch segments  30  to retract radially inward toward the mandrel  10  and thereby releasing the latch from the liner hanger  13 .  
      With reference to  FIGS. 2   a , 2   b , the mandrel  10  is releaseably connected to the liner hanger  13  such as for running in. The latch cage  12   a  is supported by the latch shoulders  35  which are profiled to normally mate with complementary profiles in the mandrel  10 . The latch shoulders  35  are retained to the mandrel  10  with the hydraulic housing  12   b  forming a sleeve or locking cylinder  50 . A piston annulus  51  is formed between the locking cylinder  50  and the mandrel  10 . The locking cylinder  50  has an uphole end  52   u  which, when axially positioned adjacent the latch shoulders  35 , retains each latch shoulder  35  to the mandrel  10  with the profiles  36 , 37  engaged. When the locking cylinder&#39;s uphole end  52   u  is repositioned downhole of the latch shoulders  35  ( FIG. 4   a ), the shoulders are free to release from the profiles  36 , 37  and become incapable of supporting axial load any longer.  
      The piston annulus  51  also forms an annular fluid cylinder having a fluid port  49  formed in the mandrel  10  between the mandrel&#39;s fluid bore  9  and the piston annulus  51 . The piston annulus  51  is sealed between the mandrel  10  and the locking cylinder  50  at an uphole seal  53  above the port  49 . An annular piston  55 , retained temporarily by a shear screw  56 , is axially movable in the piston annulus  51  in response to pressure at the port  49 . The extent of movement of the annular piston  55  is delimited by contact between a radially outward shoulder or uphole stop  58   u  protruding from the mandrel  10  below the latch shoulders  35 , and a radially inward shoulder or downhole stop  58   d  formed adjacent a downhole end  52   d  of the locking cylinder  50 . The locking cylinder  50  is movable axially on the mandrel  10 , temporarily restrained with shear screws  59 , so that contact and force from the annular piston  55  acting on the downhole stop  58   d  results in downhole movement of the locking cylinder  50 .  
      A shown in  FIG. 4   a , resulting downhole movement of the locking cylinder  50  releases the radial support of the latch shoulders  35  and the mating profiles  36 , 37  disengage, which in turn releases axial support of the latch cage  12   a . The maximum downhole movement of the locking cylinder  50  is limited by contact of the downhole stop  58   d  and a further stop  61  at a bottom sub  62  of the mandrel  10 .  
      As a precautionary measure, in an environment of variable pressure and mandrel manipulation, both the annular piston  55  and the locking cylinder  50  are temporarily restrained from premature movement under such pressures using shear screws  56 ,  59  respectively, shearable under pressures less than hydraulic actuation pressures.  
      Operationally, as shown in  FIGS. 2   a ,  2   d ,  3 - 7 , the latch segments  30  are hydraulically released. The liner hanger  13  is actuated through conventional means and is axially immovable in preparation for downhole operation such as cementing. Initially, as shown in  FIGS. 2   a  and  2   d , the latch segments  30  remain radially extended and engaged with the liner hanger  13  after running in. The latch segments  30  are retained in the engaged position by the latch cage  12   a . The latch cage  12   a  is supported axially on the latch shoulders  35  which are axially supported on the mandrel  10  as long as they are restrained radially thereto by the uphole end of the locking cylinder  50 . The locking cylinder  50  is restrained from unexpected axial motion by its shear screws  59 . The annular piston  55  is also in an idle, uphole position, restrained by the shear screws  56 .  
      With reference to  FIG. 3 , under increased fluid pressure in the bore  9 , the annular piston  55  shears free of shear screws  56 , moves downhole and engages the downhole stop  58   d  of the locking cylinder  50 . Due to the contact of the piston or as a result of increased pressure and piston force against the downhole stop  58   d , shear screws  59  are sheared, enabling downhole movement of the locking cylinder  50 . The locking cylinder  50  moves axially to rest against stop  61 . As a result of the downhole axial movement of the locking cylinder  50 , the latch shoulders  35  are no longer restrained to the mandrel  10 , removing any support for the latch cage  12   a.    
      With reference to  FIG. 4   a , while the latch shoulders  35  may fall free of the mandrel  10  of their own accord, release is assured when the mandrel  10  is picked up as shown. The mandrel  10  shears the assembly screws  29  from the latch cage  12   a  as the latch segments  30  initially resist pickup; being still engaged with the immovable liner hanger  13 . The latch shoulders  35  are released from the mandrel  10 , removing support from the latch cage  12   a  so that the latch segments retract radially to the mandrel  10  as the ribs  40 , 41  mesh.  
      As shown in  FIG. 5 , the operator continues to pick-up the running tool mandrel  10  to confirm release from the liner hanger  13  through sensing of a reduced pickup weight. The drive housing  11  drive face  21  become disengaged from the liner hanger  13  drive face  22 . The latch profile  32  of the latch segments  30  is clearly disengaged from the cooperating and receiving profile  33  of the liner hanger  13 .  
      With reference to  FIG. 6 , the running mandrel  10  tool is set back down for operations. The latch cage  12   a  and latch segments  30  are no longer supported by the latch shoulders  35  and cannot supportably re-engage the liner hanger  13 , ensuring retrieval of the running tool at completion of the operations. The drive face  21  of the uphole drive housing  11  re-engages the drive face  22  liner hanger  13  for enabling co-rotation of the mandrel  10 , drive housing  11  and rotatable liner hanger  13 . The mandrel  10  is supported by the uphole drive housing  11 .  
      At  FIG. 7 , the running tool  5  is retrieved by picking up at the mandrel  10 , shown as being retrieved through a tie-back receptacle  99  attached atop the liner hanger.  
      Mechanical Release  
      With reference to  FIGS. 8   a - 14 , the latch segments  30  may be mechanically released, typically as a backup system as a result of some failure of the hydraulic release system. Simply, the mandrel  10  is mechanically manipulated to be shifted downhole to release the latch cage  12   a  through actuation of components as introduced for the hydraulic release embodiment above. Note that the piston  55  and locking cylinder  50  need not be actuated or sheared from their screws  56 ,  59  respectively to mechanically actuate the tool  5 .  
      With reference to  FIGS. 2   c , 8   a , 8   b  and  9   b , the uphole housing  11  further comprises a clutch ring  70  sandwiched in a clutch annulus  80  between an uphole end  76  of the uphole housing&#39;s locking cylinder  20  and the mandrel  10 . The clutch ring  70  is normally supported from the mandrel  10  upon facing profiles  71 , 72  between the mandrel  10  and the uphole housing  11 . The profiles  71 , 72  comprise cooperating circumferentially segmented clutch upsets  81 , 82  extending radially from each of the clutch ring  70  and the mandrel  10  respectively forming circumferentially spaced axial passages  83  therebetween.  
      Normally, the mandrel  10  cannot pass axially through the clutch ring  70 , the clutch ring being supported by the uphole housing  11 , and the uphole housing  11  is resting on an upper end of the liner hanger  13  at the drive faces  21 , 22 .  
      As shown in  FIGS. 2   c ,  8   b  and  9   b , an indexed relative rotation of the mandrel  10  relative to the clutch ring  70  is used to align cooperating clutch upsets  81 , 82  and axial passages  83  therebetween so as to enable the mandrel  10  to be lowered axially through the clutch ring  70  and thus having sufficient range of axial motion to move through the latch cage  12   b  to release the latch segments  30 . So as to align the clutch upsets  81 , 82  and axial passages  83 , the extent of relative rotation is controlled or delimited using an arrangement of a pin  85  and J-slot  86  acting between the mandrel  10  and clutch ring  70 . Two opposing and redundant pins and J-slot  85 , 86  arrangements are shown. Additional means and safeguards are provided to avoid accidental actuation of the mechanical release as described later.  
      As shown in the particular embodiment, the J-slot  86  is located in the mandrel  10  adjacent the clutch ring  70 . Accordingly, the corresponding pin  85  is shown extending radially inwardly from the clutch ring  70  for engaging the J-slot  86 . The J-slot has a circumferential portion  87  which enables pin movement during indexed rotation. The J-slot  86  further comprises an axial portion  88  extending uphole from the circumferential portion  87  so as to enable axial movement of the pin  85  and clutch ring  70  when aligned.  
      Thus, the mandrel  10  is rotatable using LH rotation relative to the clutch ring  70 , uphole housing  12   a  and liner hanger  13 , as the pin  85  follows the circumferential portion  87 . As illustrated with the particular clutch upsets  81 , 82  shown, after ¼ turn of rotation, when the pin  85  reaches the axial portion  88  of the J-slot  86 , each clutch upsets  81  and  82  aligns with an axial passage  83  and thus can move axially downhole relative to the clutch ring  70  and uphole drive housing  11 .  
      As shown in  FIG. 2   c , each ring-side clutch upset  81  is formed with a plurality of annular grooves  89  for forming a plurality of load support shoulders extending radially inwards. Each mandrel-side clutch upset  82  is also formed with a plurality of annular grooves  89  for forming a plurality of load support shoulders. When the pin  85  resides in the circumferential portion  87  of the J-slot, the annular grooves  89  of the clutch upsets  81 , 82  are threadably engaged for bearing liner hanging loads.  
      For a ¼ turn LH rotation actuation of the mandrel, opposing ¼ turn clutch upsets  81 , 82  and axial passages  83  are implemented to utilize a high hanging load capability. Other arrangements and numbers of clutch upsets can be applied to releasably support the mandrel  10  from the clutch ring  70 .  
      With the ability to mechanically release the uphole housing  11  from the mandrel  10 , the mandrel can be shifted through the latch cage  12   a  for release of the latch segments  30 .  
      In operation, as shown in  FIG. 2   a  and wherein the hydraulic release has failed in  FIGS. 8   a ,  8   b , the latch cage  12   a  and latch segments  30  remain retained in the engaged position by the latch shoulders  35  which are in turn supported on the mandrel  10  and continue to be restrained thereto by the uphole end  52   u  of the locking cylinder  50 .  
      Having reference to  FIGS. 9   a ,  9   b , a ¼ turn LH rotation of the mandrel shears screws  90  and repositions the pin  85  to rest at the end of the circumferential portion  87  and aligned with the axial portion  88  of the J-slot  86 , aligning the clutch upsets and axial passages  81 , 83  and  82 , 83  for permitting the uphole drive sleeve  20  to be moved uphole relative to the mandrel  10  and thus relative to the latch cage  12   a . The clutch ring  70  moves to an uphole position to engage and stop at a downhole facing shoulder  91  on the mandrel  10 ; the clutch ring  70  being biased into engagement with the mandrel&#39;s shoulder  91  by the spring  23  positioned between the clutch ring  70  and the drive face  21  of the uphole housing  11 .  
      As shown in  FIG. 10 , once the clutch ring  70  has been disengaged from the mandrel  10  and moved to the uphole position, the mandrel can be set down to shear screw  29  retaining the latch cage  12   a . As shown in  FIG. 11 , further setting down of the mandrel  10  compresses the spring  23 , shifting the uphole housing  11  about the dogs  73  of the clutch ring  70 , and forces the mandrel through the latch cage  12   a  and releases the latch segments  30  to the radially inward released position.  
      As shown in  FIG. 12 , the mandrel  10  is then picked up to lift the released running tool  5 , disengaging the drive faces  21 , 22  and to enable the operator to sense a reduction in pickup weight, confirming that the running tool  5  has been released from the liner hanger  13 .  
      As was disclosed for the hydraulic operation and shown similarly at  FIG. 13 , while the running tool  5  is free from the liner hanger  13 , the running tool  5  is again set down again to re-engage the drive faces  21 , 22  and to permit co-rotation of the running tool  5  and the liner hanger  13  such as is sometimes desirable during cementing operations.  
      Finally, as shown in  FIG. 14 , once the downhole operations are completed, the released running tool  5  is picked up for retrieval from the liner hanger  13  and wellbore.  
      Barrel Ratchet  
      With reference to  FIGS. 2   c , and  16   a - 21   b , in some instances, as is the case for the mechanical release of the one embodiment of the running tool  5 , it is desirable to provide a robust one-way clutch  25 , capable of the transmission of high torque through co-rotation in a primary driving direction and release in the other ratcheting direction. While applicable to many other instances where a clutch  25  is required in high torque, uni-directional implementation, the present invention applies the principles of a novel barrel ratchet  101  within a ratchet annulus  102  formed between the mandrel  10  and the uphole housing  11  so as to impart torque and right hand (RH) rotation from the running tool mandrel  10  into the liner hanger  13  and any liner depending therefrom.  
      Further, as discussed should it be necessary to enable the mechanical release function of the mandrel  10  and clutch ring  70 , it is desired to use the clutch  25  to enable left hand (LH) rotation of the mandrel  10  relative to the uphole drive housing  11  or sleeve  20 .  
      The illustrated clutch  25  is enabled for RH locked and drivable co-rotation of the housing  11  as this is the usual embodiment used for downhole tool operation. Using a reversed orientation of the mechanical components, the clutch  25  is equally useful and can be implemented on the opposite rotational sense in tools or operation where the driving co-rotation is in the opposing LH direction.  
      With reference to the embodiment shown in  FIGS. 10, 15   a - 20   b , such a clutch  25  is implemented for enabling RH rotation of the mandrel  10  to drive RH co-rotation of the housing  11  and conversely LH rotation of the mandrel  10  results in a ratcheting, or substantially free, rotation of the mandrel relative to the housing  11 .  
      The clutch  25  comprises external mandrel splines  103  formed on the mandrel  10  ( FIGS. 15   a , 15   b ) and extending into the ratchet annulus  103  and internal housing splines  104  formed in the uphole housing  11  ( FIGS. 15   a , 15   b ,  17   a , 17   b ) and which also extend into the ratchet annulus  102 . As shown in  FIG. 10 , the mandrel splines  103  have sufficient axial extent to permit the uphole housing  11  to move axially throughout an operational range while maintaining at least some overlap of the mandrel and housing splines  103 , 104  and thus maintain co-rotation.  
      Turning to  FIGS. 16   a , 16   b , and  19   a , 19   b , the barrel ratchet  101  is shown residing in the ratchet annulus  102  formed between the mandrel and housing splines  103 , 104 . Typically, through torsional impetus, the barrel ratchet  101  can be elastically alternated between a radially expanded (ratcheting) position and radially contracted (locked) position.  
      With reference in more detail to  FIGS. 19   a , 19   b , the mandrel and housing splines  103 , 104  form profiled teeth  103   t , 104   t . The barrel ratchet  101  has a substantially cylindrical body  110  upon which is formed profiled internal teeth Ri and external teeth Ro.  
      With reference also to  FIG. 20   a , each tooth  103   t , 104   t  of the mandrel and housing splines  103 , 104  and the barrel ratchet teeth Ri,Ro form at least two faces Fi,Fo which are asymmetrical, one of faces Fi or Fo having a ramped face, angled somewhat from a tangent, and at least one of either Fo or Fi having a substantially upstanding face which is oriented more closely to a radial. The mating faces Fi,Fo of the mandrel spline&#39;s teeth  103   t  and the barrel ratchet&#39;s internal teeth Ri are complementary and the mating faces of the housing spline&#39;s teeth  104   t  and barrel ratchet&#39;s external teeth Ro are complementary as set forth in greater detail herein. Each face Fi, Fo can be characterized as having a ramped and an upstanding face; the ratchet&#39;s external teeth Ro having a ramped face For and an upstanding face Fou; and the ratchet&#39;s internal teeth Ro having a ramped face Fir and an upstanding face Fiu.  
      As shown in  FIGS. 19   a  and  20   a , when contracted, the body  110  of the barrel ratchet  101  is caused to contract radially in the ratchet annulus  102  so as to engage its internal teeth Ri with the mandrel spline teeth  103   t  while the barrel ratchet&#39;s external teeth Ro continue to remain engaged with the housing spline teeth  104   t , thereby locking the mandrel and housing splines  103 , 104  for co-rotation. Preferably the body  110  of the barrel ratchet  101  normally resides in an elastically contracted state for normally gripping the mandrel&#39;s spline  103  through the internal teeth Ri and mandrel spline teeth  103   t . Right hand rotation of the mandrel and housing spline  103 , 104  engages tooth faces Fi,Fo. Lash between the barrel ratchet  101  and housing spline  104  closes for enabling RH rotation of the housing  11 . In the particular embodiment of  FIGS. 15   a - 20   c , the orientation of the barrel ratchet teeth Ro driving the housing spline  104  form mating ramps which act to impose radial contracting forces on the flexible body  110  of the barrel ratchet  101 , superadding to the force of the grip between the mandrel spline  103  and barrel ratchet  101 . Optionally, as shown in  FIGS. 21   a  and  21   b , the barrel ratchet  101  is also effective wherein the interface of barrel ratchet teeth Ro and housing spline  104  is more upstanding or radially oriented. The orientation between the barrel ratchet&#39;s external teeth Ro and the housing spline  104  is such that radially outward wedging forces are still avoided during the driving rotation and thus separation forces of the mandrel spline  103  and barrel ratchet internal teeth Ri is also avoided.  
      As shown in  FIG. 19   b , when the body  110  of the barrel ratchet  101  is expanded radially, the housing spline  104  radially accepts the external teeth Ro sufficiently so that the internal teeth Ri are released from the teeth  103   t  of the mandrel spline  103  for enabling relative rotation therebetween.  
      The barrel ratchet  101  is a unitary member generally like a gear. The body  110  is flexible so that the root diameter of the teeth Ro, Ri can be varied which enables the expanded and contracted positioning of the tip diameters of the internal and external teeth Ri,Ro. The radial working depth of the mandrel spline  103  is less than the radial working depth of the housing spline  104 . Accordingly, throughout elastic expansion and contraction of the barrel ratchet&#39;s body  110 , the external teeth Ro remain locked for co-rotation with the housing spline teeth  103   t  while the internal teeth Ri alternate between engagement and disengagement with the mandrel spline&#39;s teeth  103   t.    
      As illustrated, in a case wherein the axial extent of the barrel ratchet  101  is wholly within the axial extent of the ratchet annulus  102  formed by the mandrel and housing splines  103 , 104 , the entire axial length of the barrel ratchet  101  is capable of expansion and contraction to enable ratcheting. It is possible that a barrel ratchet  101  need only be partially engaged in a ratchet annulus  102  and therefore only a portion of the body  110  needs to be flexible.  
      Best shown in  FIGS. 18   a , 18   b , for enabling a flexible root diameter of the internal and external teeth Ri,Ro, the cylindrical body  110  has a plurality of axially-extending slots  120  spaced periodically about its circumference. For enabling flexibility of the barrel ratchet body  110  along its entire axial extent, a first set of slots  120 , 120   a  extend axially from a first end to terminate adjacent a second end and a second set of slots  120 , 120   b  extend axially from the second end to terminate adjacent the first end, the slots of the first and second sets of slots alternating for forming alternating fingers  121  enabling flexible internal teeth Ri and flexible external teeth Ro. A root  122  of each slot  120  is contoured to relieve stress concentrations.  
      The first and second slots  120   a , 120   b  extend axially a distance less than the axial extent of the barrel ratchet  101  so that the barrel ratchet remains unitary or contiguous. The first set of slots  120   a  are circumferentially indexed from the second set of slots  120   b  so that the cylindrical body  110  remains unitary and is comprised of flexible fingers  121  of teeth cantilevered from alternating ends of the cylindrical body  110 .  
      With reference to  FIG. 20   b  (ratcheting), when the barrel ratchet  101  is expanded in the ratcheting direction, the diameter of the internal teeth Ri expands sufficiently to enable the internal teeth to slip, ride over or otherwise rotate relative to the mandrel spline  103 . With reference to  FIG. 20   a  (driving) and  FIG. 20   c  (neutral), when the barrel ratchet  101  is contracted, the diameter of the internal teeth Ri contracts sufficiently to engage the mandrel spline  103 . At rest, the barrel ratchet  101  is elastically biased to grip the mandrel  10 .  
      In the tool embodiment, when the mandrel  10  is rotationally driving ( FIG. 20   a ) the uphole housing  11  in a RH rotation for running in the liner  13 , the mandrel spline teeth  103   t  and internal teeth Ri of the barrel ratchet  100  engage at substantially upstanding faces Fiu. The face Fiu are driving faces and should there be radial forces generated in that contact Fiu, they do not act sufficiently to expand the barrel ratchet  101  and do not separate faces Fiu and thus the clutch is drivably engaged. Preferably, the circumferential orientation of the internal teeth  104   t  of the housing spline  104  is opposite of that of the mandrel spline&#39;s teeth  103   t . In other words, the ramped faces Fir of the mandrel spline  103  increase radially outwards as the ramp progresses clockwise while the ramped faces For of the housing spline  104  increasing radially outwards as the ramp progresses counterclockwise. This relative orientation has additional benefit during RH rotation for drivably rotating the uphole housing  11 ; the force vector between the external teeth ramps For aid to wedge the barrel ratchet  101  onto the mandrel spline  103 . Accordingly the faces For also form driving faces to transmit torque from the barrel ratchet  101  to the housing  11 . Little supplementary wedging force is generated if the upstanding faces For are substantially radial or at an acute angle.  
      To release the clutch  25  in opposite hand rotation, the mandrel  10  is rotated in a LH rotation for actuating the mechanical release of the clutch ring  70 . The teeth  103   t  of the mandrel spline  103  engage the internal teeth Ri of the barrel ratchet  101 , expanding the body  110  of the barrel ratchet  101  through radial forces generated between the corresponding ramped faces Fir of the teeth  103   t  of the mandrel spline and the internal teeth Ri of the barrel ratchet. The radial force vector generated by the facing ramps Fir expands the barrel ratchet  101  until the diameter of the internal teeth Ri is greater than the mandrel spline teeth  103   t . When the barrel ratchet  101  expands, the external teeth Ro are free to more fully and radially engage the teeth  104   t  of the housing spline  104 .  
      In another embodiment, as shown in  FIGS. 21   a  and  21   b , the circumferential orientation of the ramped faces For of the housing spline is the same as that of the mandrel spline Fir which is also increasing radially outwards as the ramp progresses clockwise. This orientation does not provide as much wedging force as that resulting from the embodiment of  FIGS. 20   a - 20   c.    
      Protection from Accidental Release  
      Typically downhole components are run in using RH rotation. When running in a liner, there is drag resistance to rotating the liner, causing the liner to rotationally lag the running tool rotation somewhat, elastically winding up the length of elastic liner below the running tool and the length of drill string above the running tool.  
      Right hand torque starts at the top of the mandrel  10  and is transmitted through mandrel splines  103  to the barrel ratchet  101 . The barrel ratchet  101  transmits the RH torque to the drive housing splines  104 , the drive housing  11 , the liner hanger  13  and down to the bottom of the liner string.  
      For actuation of the mechanical release and J-slot, LH torque starts at the top of the mandrel  10  and reaches mandrel splines  103  at the barrel ratchet  101 . Ratcheting therebetween permits the mandrel  10  to rotate to the left while the drive housing  11  and liner string remain stationary. This should only occur due to deliberate LH rotational actuation by an operator.  
      Inappropriate LH torque or backlash is generated at the bottom of the liner and travels up the liner string. The LH torque is a result of the RH torque building up in the liner string and then releasing. Such backlash is then transmitted from the liner hanger  13 , through the drive housing  11  and splines  104 , and to the barrel ratchet  101  which is equivalent to the usual RH torque during running in. The backlash is transmitted to the mandrel splines  103  for transmission up the mandrel  10  to the drill string, where the backlash is dissipated.  
      The clutch  25  and barrel ratchet  101  prevent the backlash from creating independent LH rotation between the drive housing  11  and the mandrel  10 , without the need of shear screws. The ratchet  101  of the present invention is equally responsive for transmitting RH rotation from the uphole components into the downhole components and for resisting LH rotation from the downhole components into the uphole components.