Patent Publication Number: US-6666275-B2

Title: Bridge plug

Description:
TECHNICAL FIELD 
     The present invention relates to retrievable bridge plugs and related setting and retrieving tools and in particular to retrievable bridge plugs for placement in pressurized hydrocarbon wells to temporarily seal a portion of the well. The bridge plug has a selectively opened and closed through bore that allows pressure equalization before retrieval and permits well service tools to pass there through without requiring removal of the bridge plug. Improper setting of the bridge plug is prevented by a setting mechanism that is locked until located in the proper size tubing. 
     DESCRIPTION OF RELATED ART 
     Bridge plugs are tools that are typically lowered into a cased oil or gas well. When set in position inside the casing, a bridge plug provides a seal to isolate pressure between two zones in the well. Retrievable bridge plugs are used during drilling and workover operations to provide a temporary separation of zones. When multilateral or multibore wells are drilled, bridge plugs are used to temporarily seal off the tubing set in the completed bores or laterals during servicing or completion of additional bores. 
     Typical bridge plugs are shown in U.S. Pat. No. 4,436,150 issued to Barker on Mar. 13, 1984; U.S. Pat. No. 4,898,239 issued to Rosenthal on Feb. 6, 1990; U.S. Pat. No. 5,058,684 issued to Winslow on Oct. 22, 1997; U.S. Pat. No. 5,727,632 issued to Richards on Mar. 17, 1998; U.S. Pat. No. 6,244,642 issued to Serafin et al. on Jun. 12, 2001. Baker sells a model “GT” LOK-SET Retrievable Bridge Plug and Model “LTC” Retrieving Head. Retrievable bridge plugs typically have anchor elements (slips or the like) and sealing elements. The anchor elements are used to grip the inside surface of a tubular member such as a well casing to prevent the set bridge plug from moving up or down. Note that as used herein, “down”, “downward”, or “downhole” refer to the direction from the wellhead toward the producing zone regardless of whether the wellbore proceeds straight and directly downward from the surface. Up, upward, and uphole is in the reverse direction of downhole. “Surface” refers either to the ground level or to the ocean floor, as applicable. The sealing elements engage the inside surface of the well casing to provide the requisite seal for the annulus defined between the bridge plug and the casing. Typically, the bridge plug is set in position by radially extending the anchor and the sealing elements to engage the well casing. To retrieve the bridge plug from the well casing, a retrieving tool is lowered down the casing to engage a retrieving latch, which, through a retrieving mechanism, retracts the anchor and the sealing elements, allowing the bridge plug to be pulled out of the well bore. 
     During well operations, a pressure differential across the plug often develops. It is desirable to equalize this pressure differential before the anchor and sealing elements are disengaged. Equalization prevents the loss of control over the bridge plug, wherein the tool may be blown up or down a well casing in response to the pressure differential. As exemplified by the prior art bridge plugs listed above, such equalization is typically effected through the opening of a bypass passage through the interior of the plug, prior to disengagement of the anchor and sealing elements. 
     However, a problem is encountered with these prior art devices in their inability to permit testing of well conditions in the completed bore. In these devices testing requires removal of the bridge plug. 
     With prior art retrievable bridge plugs dangerous situations can occur when setting is attempted in the incorrect location. The anchors and expandable seals of bridge plugs are designed to set in a narrow range of tubing sizes. When retrievable bridge plugs are to be set in tubing located in a lateral, it is essential that the bridge plug be located within the smaller lateral tubing liner before setting. Attempted setting short of the liner damages the tool and results in a defective seal off. 
     Bridge plugs having seals positioned between anchors causes the compressed seal elements to act as a compression spring. This spring force bears on the slip bodies pushing the carbide buttons on the slips deeper into the tubing. Releasing the slips requires pulling with enough force to actually rip the slip button out of the tubing wall. Typically, steeper slip angles and fewer buttons and slips are used to reduce the amount of force required to pull one set of slips loose. These solutions reduce the holding effectiveness of the slips. 
     When running the bridge plugs of the prior art in to the well, circulating ports in the inner mandrel are present to allow sufficient fluid bypass flow rates. These circulation ports weaken the inner mandrel and force flow into the interior of the mandrel. 
     SUMMARY OF THE INVENTION 
     According to the present invention, an improved retrievable bridge plug assembly and retrieving tool is provided. According to the bridge plug assembly of the present invention, an unobstructed straight central passageway extends through the plug and can be selectively opened and closed by the retrieving tool. When closed, the area below the bridge plug is isolated from the well above the plug. When open, pressure can be applied below the bridge plug and the pressure integrity below the bridge plug can be tested. In addition, this central passageway allows tool access to the area below the bridge plug assembly. For example, both “pump through” and “wire line” tools can pass through the straight central opening. The packer assembly of the present invention utilizes a liner sensor above the slips and seals that prevents the bridge plug for trying to set until the sensor is inside the proper size tubing, preventing attempted setting outside the liner. According to the bridge plug of the present invention, the slips that resist movement are located below the seal elements. This protects the slips from debris and makes the slips easier to retrieve. The improved bridge plug of the present invention utilizes a flow path around the seal slip elements through a concentric bypass between the inner mandrel and the seal/ratchet/slips mandrel. Fluid enters through slots in the lower slip body, passes through slots in the seal/ratchet/slips mandrel and exits through holes in the bypass seal body. The concentric bypass eliminates the need for circulation ports and forces fluid to circulate around the bottom of the bridge plug and through any tail pipe attached to the bottom of the bridge plug. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be better understood and its numerous objects and advantages will become more apparent to those skilled in the art by reference to the following drawings, in conjunction with the accompanying specification, in which: 
     FIG. 1 is a diagram of a multibore hydrocarbon well illustrating the one application for using bridge plug assemblies according to the present invention; 
     FIG. 2 is a schematic drawing partially in section of the a retrieving head and bridge plug assembly in accordance with the present invention connected by a section of tubing to a packer; 
     FIGS. 3A-I are detailed partial longitudinal cross-section drawings of a the retrieving head connected to the bridge plug assembly in accordance with the present invention; 
     FIG. 4 is a perspective view of an upper J-slot tube in the bridge plug assembly in accordance with the present invention; 
     FIG. 5 is a diagram of the j slot pattern in the upper J-slot tube; 
     FIG. 6 is a diagram of the seal actuation j slot pattern in the bridge plug assembly in accordance with the present invention; 
     FIG. 7 is a detailed partial longitudinal cross-section drawing of the bridge plug assembly of FIG. 3 illustrated in the run position in accordance with the present invention; and 
     FIG. 8 is a detailed partial longitudinal cross-section drawing of the bridge plug assembly of FIG. 3 illustrated in the set position in accordance with the present invention. 
    
    
     DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT 
     Referring now to the drawings where like or corresponding reference characters are utilized through out the several views to refer to like or corresponding parts there is illustrated in FIG. 1 a simplified longitudinal schematic drawing of a multilateral well showing the location of various retrievable bridge plug assemblies of the present invention. The retrievable bridge plug assembly according to a preferred embodiment of the present invention is generally designated by reference numeral  10  for purposes of description. The well  12  is illustrated as having three separated lateral bores  14  each having a tubular liner  16  set therein. Each of the bridge plug assemblies  10  are shown set in the lateral liner  16  isolating the lateral bores  14  from the well  12 . 
     In FIG. 2 a schematic diagram of the bridge plug assembly  10  of the present invention is illustrated along with a retrieving tool  20 . The bridge plug assembly  10  comprises a retrieving neck subassembly  40 , a valve and actuator subassembly  50 , liner sensor subassembly  60 , expandable seal or packer subassembly  70 , a slip or anchor subassembly  80 , a slip and seal setting subassembly  90  and a tail pipe  100 . 
     According to the present invention, bridge plug assembly  10  has a straight passageway or bore  18  extending axially through the entire bridge plug assembly  10  and its sub assemblies. Passageway  18  is connected to communicate with tail pipe  100  and provides tool and testing access to lateral bore  14  without necessitating removal of the bridge plug assembly  10  itself. Retrieving tool  20  also has a central passageway  21 . Retrieving tool  20  has pins or lugs  22  which engage a “J-slot”  42  on retrieving neck subassembly  40  to connect the retrieving tool  20  to the bridge plug assembly  10  for installation, servicing and removal. When the retrieving tool  20  is connected to bridge plug assembly  10 , passageways  18  and  21  are in sealed fluid communication. 
     A ball valve  52  in valve and actuator subassembly  50  is selectively operable to fully open and seal off passageway  18 . The valve  52  is a two-position valve and is opened when stinger portion  24  of retrieving tool  20  engages a collet assembly  54  in valve and actuator subassembly  50  when the retrieving tool  20  is connected to bridge plug assembly  10 . When the retrieving tool  20  is disconnected, valve  52  returns to the closed position. 
     The liner sensor subassembly  60  comprises spring-loaded fingers  62  that normally locks the slip and seal setting subassembly  90  to prevent it from setting. When the fingers  62  contact the end of tubular liner  16  they deflect to the unlocked position allowing setting of the bridge plug assembly  10 . By axially spacing the fingers  62  from the slips and seals, proper location of the bridge plug assembly  10  in the tubing tubular liner  16  is assured before setting. 
     Slip and seal setting subassembly  90  is utilized to set the bridge plug assembly  10 . Setting is accomplished by a series of twists, pulls and pushes applied by the retrieving tool  20  on the retrieving neck subassembly  40 . The actuator comprises a cooperating “J-slot” and pin arrangement with a ratchet to progressively expand the seal  70  and slip  80  subassemblies. Spring-loaded drag blocks  92  engage the inside wall of the tubing tubular liner  16  to assist in setting. 
     Once the bridge plug assembly  10  is set in the tubular liner  16 , retrieving tool  20  is separated and removed, and valve  52  closes. To reconnect and open the valve  52 , the retrieving tool  20  returned to engage retrieving neck subassembly  40 . To remove the bridge plug assembly  10 , the retrieving tool  20  is engaged with the retrieving neck subassembly  40  and twisted in the opposite direction from the setting procedure. 
     The details of the structure and operation of one particular embodiment of the bridge plug assembly  10  of the present invention will be described by reference to FIGS. 3-8. The illustrated embodiment is only one example of practicing the present inventions. 
     In FIGS. 3A-I the bridge plug assembly  10  is illustrated engaged by the retrieving tool  20 . Retrieving tool  20  has an outer sleeve or overshot portion  23  supporting at least one or in this embodiment three internal pins  22  for engaging the “J-slot”  42  on retrieving neck subassembly  40 . Overshot portion  23  terminates at an auger portion  27  for removing accumulated materials. The cylindrical stinger portion  24  defines axially extending passageway or internal bore  21 . Bore  21  is threaded at  25  for connection to tubing extending to the well surface. 
     Slot sleeve  41  forms the upper end of retrieving neck subassembly  40 . As will be described, slot sleeve  41  is threaded on to outer circulating port sleeve  41   a , which is in turn threaded on to outer ball valve case  41   b . An adapter  41   c  provides a threaded connection between the outer ball valve case  41   b  and bridge plug mandrel  71 . 
     As illustrated in FIGS. 4 and 5 the upward facing ends  43  of “J-slot”  42  form guide surfaces to align pins  22  with first axially extending portion  44 . Inclined guide surfaces  45  connect a second axially extending portion  46  to portion  44 . When the pins  22  in retrieving tool  20  engage the upward facing ends  43 , pins  22  are guided into alignment with portions  44 . Further downward movement (in the direction of arrow D) will cause the pins  22  to be guided in a relative clockwise direction (right hand turning of the tool in the direction of arrow cw) into portions  46  and will stop short of shoulder  47 . Lifting the retrieving tool  20  without applying counter clockwise torque (left hand turning of the tool) will cause the pins  22  to stop at shoulder  48 . As long as pins  22  remain in portion  46 , weight (downward force) and tension (upward force) can be applied to the bridge plug assembly  10 . To remove the pins  22  from the “J-slot”  42  a counter clockwise torque is applied to the retrieving tool  20  while lifting. 
     FIG. 4 illustrates a perspective of the slot sleeve  41  of the retrieving neck subassembly  40  and FIG. 5 illustrates a laid out or flat configuration of the “J-slot”  42  for receiving pin or lug  22 . A stinger extension  24   a  is threaded at one of its ends to the retrieving tool  20 . An external annular shoulder  28  is formed adjacent the other end  29  of the stinger extension  24   a . When the stinger portion  24  is inserted in or removed from the bridge plug assembly  10 , it engages collet  54  in valve and actuator subassembly  50  and moves the valve  52  between the open and closed positions. When the stinger portion  24  is inserted, its end  29  engages internal shoulder  59  on the annular collet body  58  to move the valve  52  to the open position (See FIG.  7 ). When the stinger portion  24  is removed from the bridge plug assembly  10 , shoulder  28  engages the collet  54  and pulls the collet  54  and the valve  52  to the closed position. 
     The collet  54  (illustrated in FIGS. 3A &amp; B) has a plurality of axially extending collet fingers  55  each terminating with an enlarged head  56 . Internal shoulders  57  on each of the heads  56  will engage the shoulder  28  on stinger portion  24  upon removal of the retrieving tool  20  to move the collet  54  and valve  52  to the closed position (See FIG  8 ). Note in FIG. 8 that when in the closed position the heads  56  are axially aligned with an annular relief grove  56   a  formed in slot sleeve  41 . This groove  51   a  allows the heads  56  to deflect radially outward to release the engagement of shoulders  28  and  57  during removal of the retrieving tool  20  from the bridge plug assembly  10 . 
     The collet  54  is connected to operate the valve  52  through a series of sleeves including a lower releasing sleeve holder  54   a . The valve  52  and its moving seat holder are of the type described in U.S. Pat. No. 4,633,952 to Ringgenberg issued Jan. 6, 1987, which patent is incorporated herein by reference for all purposes. In this valve, a pin engages the ball valve movable in a suitable valve seat, and relative movement between the pin and the seat causes the ball valve to rotate to open and to close. 
     According to the present invention, the valve and actuator subassembly  50  has the capacity to hold the valve  52  in either the open or closed positions. A releasing sleeve  54   b  is supported in an external annular groove defined between collet  54  and releasing sleeve holder  54   a . Releasing sleeve  54   b  has upward and downward facing tapered annular shoulders  54   c . A ring spring  54   d  is contained in an internal annular groove  54   e  defined between slot sleeve  41  and circulating port sleeve  41   a . Groove  54   e  is slightly axially longer and slightly radially larger than the ring spring  54   d  allowing the ring spring  54   d  to deflect radially outward. Ring spring  54   d  has upward and downward facing tapered annular shoulders  54   f . As retrieving tool  20  is forced into the bridge plug assembly  10 , the downward facing tapered shoulder  54   c  on releasing sleeve  54   b  engages upward facing shoulder  54   f  on ring spring  54   d  and deflects the ring spring  54   d  radially outward into groove  54   e  allowing the releasing sleeve  54   b  to pass through ring spring  54   d . As the releasing sleeve  54   b  clears ring spring  54   d , ring spring  54   d  snaps back to its original position. The ring spring  54   d  then holds the retrieving tool  20  in position with the valve  52  deflected to the open position. To remove the retrieving tool  20  the process of deflecting the ring spring  54   d  is repeated in the opposite direction. 
     In FIG. 3D liner sensor subassembly  60  is illustrated in detail. As previously disclosed the liner sensor subassembly  60  acts as a lock to prevent setting of the bridge plug assembly  10  unless it is located inside a liner. Tubular lock body  61  of linear sensor subassembly  60  axially slides along the outer diameter of mandrel  71 . Body  61  is in turn connected to the ratchet mandrel  91  of the slip and seal setting subassembly  90 . Fingers  62  are mounted on pivots  63  in axially extending grooves formed in body  61 . Compression springs  64  urge the fingers  62  to rotate in a clockwise direction with the lug end  65  contacting an annular locking groove  71   a  formed in the exterior of mandrel  71 . In the run-in position (See FIG.  3 D), lug ends  65  engage groove  71   a  and lock the mandrel  71  and body  61  against relative axial movement. When the fingers  62  encounter a liner or appropriate size casing, the fingers  62  are rotated to compress springs  64  lifting lug ends  65  out of groove  71   a , freeing the body  61  and ratchet mandrel  91  to slide axially along mandrel  71  to set the bridge plug assembly  10 . Releasing the fingers  62  allows the body  61  to slide along mandrel  71  in the direction of arrow “U” until shoulder  66  contacts shoulder  41   d  on adapter  41   c . Adapter  41   c  is connected by threads to mandrel  71 . According to the present invention the tool could be installed as a packer by disconnecting adapter  41   c  from mandrel  71 . Tubing could be connected to the threads on mandrel  71  by using a thread adapter or the like. 
     Ratchet mandrel  91  extends through the seal subassembly  70  and slip subassembly  80  and terminates at its lower end with a set of circumferentially extending ratchet teeth  91   a . Axially extending grooves  91   b  are formed in the ratchet mandrel  91  and extend along the axial length of the teeth  91   a . A plurality of circumferentially spaced “Tee-bar” ratchet pawls  91   c  are held in grooves  91   b  by circumferential tension springs  91   d . When in the run position shown in FIGS. 3F-H, teeth (not shown) on pawls  91   c  are radially spaced from and do not engage the teeth  91   a  as they are held axially off the teeth  91   a  by enlarged diameter portion  71   b  of mandrel  71 . When the liner latch or fingers  62  is released the ratchet mandrel  91  axially moves along mandrel  71  in the direction of arrow U. This axial movement positions the pawl  91   c  over reduced diameter portion  71   c  (off the enlarged portion  71   b ) allowing the teeth on pawl  91   c  to engage the teeth  91   a . As will be explained the slip and seal setting subassembly  90  is used to force the pawl  91   c  to move along the teeth  91   a  in the direction of arrow U to axially compress and set the seal and slip subassemblies. 
     FIGS. 3E-3H illustrate one embodiment of the seal  70 , slip  80  and slip and seal setting  90  subassemblies. As best illustrated in FIG. 3E the lower end of leek body  61  terminates with an enlarge portion  61   a . Portion  61   a  is internally threaded at  61   b  to receive and connect to external threads on the upper end of ratchet mandrel  91 . A suitable bypass seal assembly  61   c  is mounted in an internal groove in portion  61   a . This seal  61   c  cooperates with a seat  71   g  (enlarged diameter portion on mandrel  71 ) and acts as a valve to selectively open and close an internal passageway for well fluids to bypass the seal and slip subassemblies. In the unset position (FIG. 3E) the bypass passageway is open, in that, the seal  61   c  is axially located over reduced diameter portion  71   c  of mandrel  71  creating an annular bypass passageway  61   d  between the reduced diameter portion  71   c  of mandrel  71  and the interior of enlarged portion  61   a . When in the FIG. 3E run position, a plurality of radially extending ports  61   e  in enlarged potion  61   a  communicate with passageway  61   d . As the tool is lowered into the well, well fluids bypass the seal and slip subassemblies  70  and  80  through the interior of ratchet mandrel  91  (see arrow  71   f ), past seal  61   c  through passageway  61   d  and out ports  61   e . When body  61  is moved axially in the direction of arrow “U” to the set position, seal  61   c  will engage the seat  71   g  closing passageway  61   d.    
     Seal subassembly  70  comprises suitable radially expandable deformable annular seal elements  72  positioned around ratchet mandrel  91  axially between upper and lower shoes  73  and  74 , respectively. In the present embodiment seal elements  72  comprise elastomeric portions. As is conventional in downhole axial seal assemblies of this type, axial compression during setting the seal elements  72  radially deforms (expands) the seal elements  72  to seal against the interior of the tubular member in which the plug is set. The setting operation forces the lower shoe  74  in the direction of arrow “U” toward the upper shoe  73  compressing the seal elements  72 . To unset or retrieve the plug, lower shoe  74  is released to move away from upper shoe  73  relaxing the seal elements  72  from engagement with the tubular member. 
     As illustrated in FIG. 3F slip subassembly  80  comprises upper and lower slip bodies  82  and  83 , respectively, mounted axially slide on the ratchet mandrel  91 . Each slip body  82  and  83  has a plurality of ramp surfaces  82   a  and  83   a  for cooperating with ramp surfaces on upper and lower slips  84  and  85 , respectively. Lower slip body  83  has a plurality of axially extending slot shaped ports  83   b  providing fluid communication between the exterior of slip subassembly  80  and flow path  71   f . A split ring collar  86  holds the individual slips  84  and  85  in place. The tool setting process causes the slip bodies  82  and  83  to be moved toward each other causing the ramp surfaces  82   a  and  83   a  to engage the slips  84  and  85  and force them radially outward to engage the wall of the surrounding tubular member. As previously mentioned, during setting the teeth on pawl  91   c  engage the teeth  91   a  on ratchet mandrel  91  (pawl  91   c  is positioned over reduced portion  71   c ). The teeth on the pawl  91   c  and ratchet mandrel  91  are inclined to slip in the set direction during setting. In the illustrated embodiment buttons (carbide teeth)  82   b  and  82   c  are formed on the exterior of the slips  84  and  85  to assist in gripping the interior wall of the tubular member. During unsetting or retrieving, the teeth on pawl  91   c  are separated from teeth  91   a  allowing the slip bodies  82  and  83  to move apart freeing the slips  84  and  85  to radially retract from engagement with the surrounding tubular member. It should be noted that the slips  84  and  85  that resist movement are located below the seal elements  72 . This configuration protects the slips  84  and  85  from debris and makes the slips  84  and  85  easier to release and retrieve. 
     The details of the slip and seal setting subassembly  90  is illustrated in FIGS. 3G-3H and  6 . Spring  93   a  contacts upward facing annular shoulder  94   a  on collar adapter  94   b . Spring  93   a  is axially compressed between push block  93   c  and shoulder  94   a . During setting spring  93   a  applies an axial force through push block  93   c  against the pawls  91   c  to bias the teeth on pawls  91   c  into engagement with teeth  91   a.    
     Spring  93   b  is compressed between the ratchet mandrel  91  and an upward facing annular shoulder  94   d  on lower mandrel  94 . Spring  93   a  urges the ratchet mandrel  91  upward (direction of arrow “U”) with respect to the lower mandrel  94 . Lower mandrel  94  is positioned between and connected by threads to mandrel  71  and lower mandrel extension  97 . Lower mandrel extension  97  is coupled to tail pipe  100 . 
     Drag block body  95  is connected to the collar adapter  94   b  by a collar  94   c . Drag block body  95  has a plurality of axially extending slots  95   a  in which are mounted the drag blocks  92 . Drag blocks  92  are biased outward by leaf springs  92   a . Tabs  92   b  on drag blocks  92  limit radially outward travel to the position shown in FIG.  3 H. Drag blocks  92  will engage the interior wall of the surrounding tubular member and cause frictional or drag forces resisting movement within the tubular member and it is these forces that are used to manipulate the bridge plug assembly  10  between the set and unset positions. The lower end of the drag block body  95  is connected by threads to drag block sleeve  96 . 
     Lugs  99  on mandrel  94  engages to a pair of “J-slots” in sleeve  98  to control the setting and releasing of the bridge plug assembly  10 . In FIGS. 3H and 3I, sleeve  98  is shown captured in the annulus between the inside of drag block body  95  and outside of lower mandrel  94 . Sleeve  98  is mounted to move with drag block body  95  and is movable with respect to lower mandrel  94 . Sleeve  98  is held in axial position between shoulder  96   a  on drag block sleeve  96  and shoulder  95   b  on drag block body  95 . According to the present invention the sleeve  98  is simple to manufacture in that the slot pattern is cut in a sleeve rather than machined as a blind slot in a mandrel. It is envisioned that the slot pattern could be cut in one or more pieces of flat plate and later rolled into pieces when assembled form a sleeve. Changing the “J-slot” pattern to accommodate running the tool of the present invention in combination with different tools is a simple matter of removing and replacing the sleeve  98 . Drag block sleeve  96  is unthreaded from the drag block body  95  to allow access to and removal of sleeve  98 . 
     In FIG. 6 a slot pattern is illustrated flat with the lug  99  shown in various positions therein. Slot  98   a  has a first axially extending leg, which for descriptive purposes is designated as  98   a . Lug position  99   a  is the pick up position. As the bridge plug assembly  10  is manipulated into the well a right hand torque is applied on lug  99  to maintain it in leg  98   a . The axial length of leg  98   a  limits relative axial movement between the drag block body  95  and mandrel  94 . 
     When in the proper well location for installation, the string is lifted up moving to lug position  99   a . Left hand torque is applied while transferring weight down to the drag blocks  92  to move the lug  99  through the lug position  99   b  in inclined transition leg  98   b  and into the axially elongated transition leg  98   c . As the lug  99  moves down to lug position  99   c , mandrel  71  moves through the ratchet mandrel  91  until the pawl  91   c  reaches the reduced diameter portion  71   c  allowing the teeth on pawl  91   c  to engage with the teeth  91   a . Further downward pressure on the string moves the lug  99  to lug position  99   d  into the setting leg  98   d . Setting is accomplished by first applying and then relaxing downward force causing the pawl  91   c  to move up the teeth  91   a  on ratchet mandrel  91 . As previously described, when the pawl  91   c  moves up on the ratchet mandrel  91 , the seal subassembly  70  and slip subassembly  80  are set. As previously discussed, the bypass passageway  61   d  closes as the bridge plug assembly  10  is set. The retrieving tool  20  can be released and removed from the bridge plug assembly  10 . 
     To release a previously set bridge plug assembly  10 , the retrieving tool  20  engages the tool, then apply right hand torque and lift up. The lug  99  will move back into the transition leg  98   c  and the mandrel  71  will move up until the pawl  91   c  is engaged by the enlarged diameter portion  71   b  of the mandrel  71 . This frees the pawl  91   c  from the teeth  91   a  and allows the seal and slip subassemblies  70  and  80  to relax and return to the unset position shown in FIG.  3 . Also moving the mandrel  71  will open the bypass passageway  61   d.    
     Leg  98   e  of the slot  98   a  is present to allow left hand torque to be applied for aiding in the removal of the bridge plug assembly  10  with downward force while running in conjunction with a packer. It is to be understood that a set of sleeves  98  with different “J-slot” patterns could be provided with each tool. Each sleeve could have a pattern accommodating a particular combination of tools. The present invention can conceivably be used as a storm valve, closing off the well bore and retaining the work string below the bridge plug. The retrieving neck and overshot can be removed, then replaced with a standard top adapter allowing the bridge plug to be converted to a packer. 
     The operation and construction of the present invention will be apparent from the foregoing description. While the embodiment shown and described has been characterized as being preferred, it will be readily apparent that various changes and modifications could be made therein without departing from the scope of the invention as defined in the following claims.