Abstract:
A hydraulically controlled packer for an oil or gas well is disclosed that is capable of being hydraulically unset. One embodiment of the invention is capable of being hydraulically unset prior to locking thus allowing fine tuning of packer location in relation to oil-bearing strata. Other embodiments of the invention are capable of being hydraulically unlocked and unset for further use within the oil or gas well without being withdrawn to the surface for reassembly. The invention may be used in downhole well tools other than packers.

Description:
RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Application No. 60/098,851, filed Sep. 2, 1998. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates generally to oil and gas well completion and production. In particular, the present invention relates to hydraulically controlled packer structures and associated methods utilized in well completion and production activities. 
     2. Description of the Prior Art 
     It is well known in the art to provide a well packer between the outer casing and the production tubing of an oil or gas well to isolate and seal off production fluids. It is also well known to set such packers hydraulically. Examples of hydraulically set packers can be found in U.S. Pat. Nos. 3,456,723, 3,603,388 and 4,263,968. In the hydraulic packers of the prior art, the setting of the packer would lock the packer in place within the outer casing of the well. To release the prior art packer required mechanical axial or rotational motion so that screws or other retaining means would shear and allow the packer to relax and be withdrawn from the well. In order to reuse the packer of the prior art, it was necessary to remove the packer completely from the well for reassembly with new shear screws or similar retaining means. Also, once set and locked, the packer could not be repositioned within the well bore. This made fine tuning of the packer&#39;s location relative to oil-bearing strata difficult. 
     The mechanical method for releasing prior art packers is particularly disadvantageous in wells containing multiple stacked packers. In these wells, the force required to shear the packers free requires the use of slip joints between packers set in close proximity to assure release of the packers individually. In addition, the modern trend toward intelligent completion components requires hydraulic and electrical conduits through packers. These conduits are easily damaged when mechanical releasing means are used. 
     Accordingly, there exists a need for a hydraulic packer that can be set, unset and reset prior to locking so that the packer location in relation to oil-bearing strata can be fine tuned and well completion components can be functionally checked. There is also a need for a hydraulic well packer that can be unset and reset without rendering the setting and locking mechanism inoperable so that the well packer can be easily relocated within the well casing without the need to retrieve and reassemble the well packer. Additionally, there is a need for a hydraulic well packer that can be released through application of hydraulic pressure rather than through mechanical axial or rotational motion to allow packer stacking and to protect hydraulic and electrical conduits. These needs are met by the present invention. 
     SUMMARY OF THE INVENTION 
     The present invention is directed to various embodiments of a hydraulic well packer. Like prior art hydraulic packers, the hydraulic packer of the present invention uses hydraulic pressure to set and lock within a well casing. In addition, one embodiment of the present invention is capable of unsetting and resetting prior to locking to allow fine tuning of the packer&#39;s position within a well. In other embodiments, the hydraulic packer of the present invention is capable of hydraulically unlocking and unsetting so that the packer can be reused in another location within a well without the need for withdrawal from the well for reassembly. The hydraulic unset and release features of the various embodiments also offer advantages in cases where multiple packers are closely stacked or where hydraulic and electrical conduits extending through the packer could be damaged by mechanical motion. The various embodiments of the present invention are summarily described below. 
     A first embodiment of the present invention is capable of being hydraulically set, unset and reset prior to locking. This embodiment uses three discrete sources of hydraulic pressure, a setting port, an unsetting port, and a locking port. The object of this embodiment is the ability to set and unset the packer multiple times without locking the packer in place. This embodiment features at least one double acting setting piston and at least one locking piston with a ratcheted surface. The setting piston operates slips and sealing elements in the conventional manner. Hydraulic pressure from the setting port actuates the double acting setting piston such that the slips and sealing elements engage the well casing wall. Conversely, hydraulic pressure from the unsetting port actuates the double acting setting piston in the opposite direction allowing the slips and sealing elements to return to their running positions. In this manner, the packer can be repositioned multiple times. When the packer is in the desired position and hydraulically set, hydraulic pressure from the locking port actuates the locking piston. The locking piston abuts the setting piston and the ratcheted surface of the locking piston engages matching ratchets on the mandrel thus locking the slips and sealing elements in place. Once locked in place, this packer can be removed in the conventional manner by axial movement that shears screws thus requiring removal and reassembly prior to further use. Alternatively, hydraulic pressure applied to a release port can shear screws to release the packer. 
     A second embodiment of the present invention is capable of being hydraulically set and locked as well as hydraulically unlocked and unset. This embodiment uses two distinct sources of hydraulic pressure, a setting port that sets and locks the packer and an unsetting port that unlocks and unsets the packer. A feature of this embodiment is the ability to set/lock and unlock/unset multiple times without being removed from the well. This embodiment uses at least one double acting piston with a cavity having a small section and a large section. The fingers of a collet are disposed within the cavity. The cavity is shaped such that when the fingers are within the small section they are held tightly against the mandrel. Conversely, when the fingers are within the large section the fingers can be readily lifted away from the mandrel. The interior surface of the fingers has ratchets that are designed to engage matching mandrel ratchets and lock the collet in place. The opposite end of the collet is fixed to actuating means that actuate the slips and seal elements in a conventional manner. Application of hydraulic pressure from the setting port forces the double acting piston to carry the fingers over the mandrel ratchets thus setting and locking the packer. Application of hydraulic pressure from the unsetting port forces the double acting piston in the opposite direction thus lifting the fingers away from the mandrel and unsetting the packer to a running configuration. 
     A third embodiment of the present invention is also capable of being hydraulically set and locked as well as hydraulically unlocked and unset. This embodiment uses two distinct sources of hydraulic pressure, a setting port that sets and locks the packer and an unsetting port that unlocks and unsets the packer. The hydraulic packer of this embodiment is capable of being set/locked and unlocked/unset multiple times without being removed from the well. This embodiment features at least one double acting piston disposed to move axially and capable of actuating slips and seal elements in a conventional manner. At least one locking piston is disposed within the double acting piston and oriented to actuate in a direction perpendicular to the longitudinal axis of the mandrel. The surface of the spring loaded locking piston adjacent to the mandrel is ratcheted and designed to engage matching ratchets on the mandrel. The locking piston is spring loaded so that it naturally presses against the mandrel. Within the locking piston is at least one plunger valve that is normally closed to a bleed port within the locking piston. The packer is set and locked by applying hydraulic pressure to a setting chamber that forces the double acting piston to slide axially and engage the slips and sealing elements. As the double acting piston slides, the locking piston is carried with it and engages the mandrel ratchets thus locking the slips and sealing elements. To unlock and unset the packer, hydraulic pressure from the unsetting port forces the locking piston away from the surface of the mandrel. The plunger valve is sized to open when the locking piston ratchets are clear of the mandrel ratchets. Upon opening, the plunger valve allows pressurized hydraulic fluid from the unsetting port into an unsetting chamber that forces the double acting piston back to its running position and unsets the packer. 
     A fourth embodiment of the present invention is capable of being hydraulically set and locked as well as unlocked and unset. This embodiment uses two distinct sources of hydraulic pressure, a setting port that sets and locks the packer and an unlocking port that unlocks the packer so that it can unset. The hydraulic packer of this embodiment is capable of being set/locked and unlocked/unset multiple times without being removed from the well. This embodiment features at least one setting piston disposed to move axially and capable of actuating slips and seal elements in a conventional manner. Ratchets on the setting piston engage matching ratchets on the interior of a rotating lock ring. The ratchets on the setting piston and the rotating lock ring have axial grooves that allow the ratchets to disengage when the rotating lock ring is rotated in relation to the setting piston. Likewise, the ratchets reengage upon further rotation of the rotating lock ring. At least one unlocking piston in communication with the unlocking port transmits axial motion to at least one annular housing capable of axial and rotational motion. The annular housing includes a tab that slides within a helical groove in the packer housing. The annular housing is slidably connected to the rotating lock ring so that rotational motion is transmitted to the rotating lock ring. Axial motion of the unlocking piston is converted into rotational motion of the rotating lock ring through the interaction of the annular housing and the helical groove. To set and lock the packer, hydraulic fluid from the setting port pressurizes a setting chamber and causes the setting piston to axially translate and engage the slips and seal elements. The ratchets on the setting piston and rotating lock ring engage and lock the packer in place within the well casing. To unlock and unset the packer, hydraulic pressure is introduced into the unlocking chamber which causes the rotating lock ring to rotate and disengage the ratchets. After the setting piston is unset, hydraulic pressure on the unlocking port is released allowing the rotating lock ring to rotate to its original position thus reengaging the ratchets. 
     Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention, when considered in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIGS. 1A through 1G are continuations of each other and form an elevational view in cross-section showing the hydraulic packer of the first embodiment of the invention in running configuration. 
     FIGS. 2A through 2C are continuations of each other and form an elevational view in cross-section showing a portion of the hydraulic packer of the first embodiment of the invention in set configuration prior to locking. 
     FIG. 3 is an elevational view in cross-section showing a portion of the hydraulic packer of the first embodiment of the invention in locked configuration. 
     FIGS. 4A through 4B are continuations of each other and form an elevational view in cross-section showing a portion of the hydraulic packer of the second embodiment of the invention in running configuration. 
     FIGS. 5A through 5B are continuations of each other and form an elevational view in cross-section showing a portion of the hydraulic packer of the second embodiment of the invention in locked configuration. 
     FIG. 6 is an elevational view in cross-section showing a portion of the hydraulic packer of the second embodiment of the invention being unset. 
     FIGS. 7A through 7B are continuations of each other and form an elevational view in cross-section showing a portion of the hydraulic packer of the third embodiment of the invention in running configuration. 
     FIGS. 8A through 8B are continuations of each other and form an elevational view in cross-section showing a portion of the hydraulic packer of the third embodiment of the invention in locked configuration. 
     FIG. 9 is an elevational view in cross-section showing a portion of the hydraulic packer of the third embodiment of the invention being unset. 
     FIGS. 10A through 10C are continuations of each other and form an elevational view in cross-section showing a portion of the hydraulic packer of the fourth embodiment of the invention in running configuration. 
     FIG. 11 is an elevational view in cross-section showing a portion of the hydraulic packer of the fourth embodiment of the invention being unlocked from running configuration. 
     FIGS. 12A through 12C are continuations of each other and form an elevational view in cross-section showing a portion of the hydraulic packer of the fourth embodiment of the invention in locked configuration. 
     FIG. 13 is an elevational view in cross-section showing a portion of the hydraulic packer of the fourth embodiment of the invention being unlocked prior to unsetting. 
     FIG. 14 is a section view through line  14 — 14  of FIG.  13 . 
     FIG. 15 is a perspective cut away view of the helical groove of the fourth embodiment of the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In a broad aspect, this invention comprises a downhole well apparatus that includes a support mandrel ( 23 ,  36 ,  59 ,  150 ) disposable inside of a well casing ( 14 ,  47 ,  152 ,  154 ), a plurality of slips ( 7 ,  45 ,  56 ,  71 ), at least one seal element ( 8 ,  46 ,  57 ,  72 ), at least one setting piston ( 4 ,  29 ,  55 ,  70 ), a source of setting hydraulic pressure (not shown apart from its associated port  1 ,  28 ,  53 ,  68 ), and a source of unsetting hydraulic pressure (not shown apart from its associated port  2 ,  27 ,  54 ,  69 ). The setting piston is movably disposed within the mandrel. The slips, which are supported on the mandrel, are movable relative to the mandrel between an inwardly retracted running position and an outwardly extending set position. The movement of the slips is generated by the movement of the setting piston, which also causes the seal elements to compress into sealing relationship between the support mandrel and the well casing. The movement of the setting piston, in turn, is caused by the sources of setting and unsetting hydraulic pressure. In response to setting hydraulic pressure, the setting piston sets the slips and seal elements. In response to unsetting hydraulic pressure, the setting piston unsets the slips and seal elements. 
     In one embodiment, the invention further comprises a locking piston ( 9 ) and a source of locking hydraulic pressure (not shown apart from its associated port  3 ). In response to locking hydraulic pressure, the locking piston moves against and locks the setting piston in place. The locking piston preferably includes ratchets ( 20 ,  48 ,  60 ,  78 ) that engage matching ratchets ( 21 ) associated with the mandrel to unidirectionally lock the locking piston in place as it moves. 
     In another embodiment, the movement of the setting piston is still caused by the sources of setting and unsetting hydraulic pressure. However, in this embodiment, in response to setting hydraulic pressure, the setting piston not only sets but also locks the slips and seal elements. And, in response to unsetting hydraulic pressure, the unsetting piston not only unsets but also unlocks the slips and seal elements. 
     This invention may be practiced with a variety of embodiments. Four embodiments of the invention, each including some additional elements and structure, will now be presented and discussed. 
     1. Embodiment #1 
     A first embodiment of the hydraulic packer of the present invention is capable of being hydraulically set, unset and reset prior to locking. Referring now to FIGS. 1A through 1G, the embodiment uses three discrete sources of hydraulic pressure, a setting port  1 , an unsetting port  2 , and a locking port  3 . These ports are in communication with sources of hydraulic pressure (not shown), which may consist of hydraulic lines extending to the surface, hydraulic accumulators, or other similar devices well known to those skilled in the art. The hydraulic packer includes at least one double acting setting piston  4  which is attached to and operates at least one upper slip wedge  5  to compress slips  7  and sealing elements  8  in a conventional manner. The hydraulic packer further includes at least one locking piston  9 . While running the hydraulic packer downhole, the double acting setting piston  4  is held in place by screws  6  and  99  and the locking piston is held in place by screw  10 . 
     Referring now to FIGS. 1A through 1F and  2 A through  2 D, upon application of hydraulic pressure to the setting port  1 , the setting cavity  11  is pressurized and applies force to a surface  12  of the double acting setting piston  4 . Upon application of sufficient hydraulic pressure, screws  6  and  99  shear and allow the double acting setting piston  4  to move in the setting direction. As the double acting setting piston  4  moves in the setting direction, the upper slip wedge  5  forces slip  7  into contact with lower slip wedge  13 . As the double acting setting piston  4  continues to move in the setting direction, slips  7  are forced outward and into engagement with the well casing wall  14 . Continued movement of the double acting setting piston  4  in the setting direction compresses sealing elements  8  thus effecting a seal between the well casing wall  14  and the production tubing  15 . A wide variety of slip and sealing element configurations are old and well known in the art. As will be appreciated by those skilled in the art, the present embodiment could be modified to function with a variety of other slip and sealing element configurations. It is to be understood that the embodiment described herein includes other slip and sealing element mechanisms that would be known to a skilled artisan. 
     To unset the double acting setting piston prior to locking so that the position of the packer can be fine tuned, hydraulic pressure is applied to the unsetting port  2  which pressurizes the unsetting chamber  16  applying force to a surface  17  of double acting setting piston  4 . This force unsets double acting setting piston  4  to its original position and allows the sealing elements  8  and slips  7  to retract to their running positions so that the packer can be moved. 
     Referring now to FIGS. 1A through 1F and  3 , once a desirable packer position is attained and the packer is set as described above, hydraulic pressure is applied to the locking port  3  which pressurizes the locking chamber  18  applying force to a surface  19  of locking piston  9 . Upon application of sufficient force, screw  10  shears and allows locking piston  9  to move in a locking direction. As locking piston  9  moves in a locking direction, locking piston ratchets  20  engage matching mandrel ratchets  21 . In the preferred embodiment, the mandrel ratchets  21  are machined into an annular ring  22  that is axially fixed about the mandrel  23 . This assembly has disassembly and maintenance advantages. However, a skilled artisan will recognize that the mandrel ratchets  21  could also be machined directly into the mandrel  23 . As locking piston  9  continues to move in a locking direction, it abuts double acting setting piston  4  thus locking the packer assembly in place. 
     Referring now to FIG. 1E, this embodiment of the packer is released through the application of axial force to production tubing  15  which shears screw  24  allowing locking dog  25  to slide into groove  26  thus releasing the assembly. This method of releasing is old and well understood in the art. It requires that the packer be removed from the well for reassembly prior to further use. In a further embodiment of the present invention, hydraulic pressure may be applied to a distinct release port  97  pressurizing chamber  98  and causing release piston  96  to shear screw  24  allowing locking dog  25  to slide into groove  26  thus releasing the assembly. The hydraulic release feature described herein is particularly desirable in cases where multiple hydraulic and electrical conduits through the packer need to be protected from damage. 
     2. Embodiment #2 
     A second embodiment of the present invention is capable of being hydraulically set and locked as well as hydraulically unlocked and unset. Referring now to FIGS. 4A-4B, this embodiment uses two distinct sources of hydraulic pressure, a setting port  28  (also functions as the locking port) that sets and locks the packer and an unsetting port  27  that unlocks and unsets the packer. These ports are in communication with sources of hydraulic pressure (not shown), which may consist of hydraulic lines extending to the surface, hydraulic accumulators, or other similar devices well known to those skilled in the art. This embodiment uses at least one double acting annular piston  29  (which functions as both the setting piston and the locking piston) with an annular cavity  30  having a small section  31  and a large section  32 . A segmented retaining ring  33  and the fingers  34  of a collet  35  are disposed within the annular cavity  30 . The segmented retaining ring  33  is held about the fingers  34  by garter springs  43 . In the preferred embodiment a segmented retaining ring  33  is separate from the fingers  34  for ease of manufacture and maintenance. However, a skilled artisan will recognize that the fingers  34  could be shaped so as to fit the small section  31  of the annular cavity  30  thus eliminating the segmented retaining ring  33 . The annular cavity  30  is shaped such that when the segmented retaining ring  33  and fingers  34  are within the small section  31  they are held tightly against the mandrel  36 . Conversely, when the segmented retaining ring  33  and fingers  34  are within the large section  32  the fingers  34  can be readily lifted away from the mandrel  36 . While running the hydraulic packer downhole, the double acting annular piston is held in place by a lock ring  37  held between an annular groove  38  on the exterior of double acting annular piston  29  and a chamfered annular groove  39  on the interior surface of the packer wall  40 . 
     Referring now to FIGS. 8A and 8B, setting and locking of the packer is achieved by application of hydraulic pressure to the setting port  28  which pressurizes the setting chamber  41  applying force to a surface  42  of double acting annular piston  29 . Upon application of sufficient force, lock ring  37  compresses allowing double acting annular piston  29  to move in a locking direction. As double acting annular piston  29  moves in a locking direction, segmented retaining ring  33  and fingers  34  slide into the small section  31  of annular cavity  30  and are pulled in the locking direction by double acting annular piston  29 . Fingers  34  and collet  35  are fixedly attached to slip and sealing element actuating means  44 . Thus, continued movement of the double acting annular piston  29  in the setting direction engages slips  45  and compresses sealing elements  46  thus effecting a seal between the well casing wall  47  and mandrel  36 . A wide variety of slip and sealing element configurations are old and well known in the art. As will be appreciated by those skilled in the art, the present embodiment could be modified to function with a variety of other slip and sealing element configurations. It is to be understood that the embodiment described herein includes other slip and sealing element mechanisms that would be known to a skilled artisan. As the double acting annular piston  29  continues to move in a setting direction pulling segmented retaining ring  33  and fingers  34 , finger ratchets  48  engage matching mandrel ratchets  49  thus locking the packer. 
     Referring now to FIG. 6, unsetting of the packer is achieved by application of hydraulic pressure to the unsetting port  27  which pressurizes the unsetting chamber  50  applying force to a surface  51  of double acting annular piston  29 . This force causes double acting annular piston  29  to move in the unsetting direction and to slide in relation to the segmented retaining ring  33  and fingers  34  such that the segmented retaining ring  33  and fingers  34  are contained within the large section  32  of the annular cavity  30 . As the double acting annular piston  29  continues to slide in relation to the segmented retaining ring  33  and fingers  34 , a disengaging wedge  52  formed on the double acting annular piston  29  within the annular cavity  30  lifts the fingers  34  away from the mandrel  36  so that the ratchets  48  and  49  disengage. In the preferred embodiment, fingers  34  are spring loaded to circumferentially expand to aid disengagement of ratchets  48  and  49 . With ratchets  48  and  49  disengaged, additional application of hydraulic pressure forces double acting annular piston  29  to continue to move in the unsetting direction returning the packer to the running configuration. At the end of the unset stroke, lock ring  37  expands into chamfered annular groove  39  to lock the packer in the running configuration. 
     3. Embodiment #3 
     A third embodiment of the present invention is capable of being hydraulically set and locked as well as hydraulically unlocked and unset. Referring now to FIGS. 7A-7B, this embodiment uses two distinct sources of hydraulic pressure, a setting port  53  (also functions as the locking port) that sets and locks the packer and an unsetting port  54  that unlocks and unsets the packer. These ports are in communication with sources of hydraulic pressure (not shown), which may consist of hydraulic lines extending to the surface, hydraulic accumulators, or other similar devices well known to those skilled in the art. This embodiment features at least one double acting piston  55  (which functions as the setting piston) disposed to move axially and at least one locking piston  58  disposed within the double acting piston  55  and oriented to actuate in a direction perpendicular to the longitudinal axis of the mandrel  59 . A ratchet surface  60  of the locking piston  58  is adjacent to the mandrel  59  and designed to engage matching ratchets  61  on the mandrel  59 . The locking piston  58  is spring loaded so that it naturally presses against the mandrel  59 . Within the locking piston  58  is at least one plunger valve  62  that is normally closed to a bleed port  63  within the locking piston  58 . 
     Referring now to FIGS. 8A-8B, the packer is set and locked by applying hydraulic pressure to the setting port  53  which pressurizes setting chamber  64  thus exerting force upon a surface  65  of double acting piston  55 . Upon application of sufficient hydraulic pressure, the friction between the locking piston  58  and mandrel  59  is overcome and the double acting piston  55  moves in a setting direction. As the double acting piston  55  moves in a setting direction, it actuates slips  56  and seal elements  57  in a conventional manner. A wide variety of slip and sealing element configurations are old and well known in the art. As will be appreciated by those skilled in the art, the present embodiment could be modified to function with a variety of other slip and sealing element configurations. It is to be understood that the embodiment described herein includes other slip and sealing element mechanisms that would be known to a skilled artisan. As the double acting piston  55  slides, the locking piston  58  is carried with it. The locking piston ratchets  60  engage the mandrel ratchets  61  thus locking the slips  56  and sealing elements  57  in place. 
     Referring now to FIGS. 8A,  8 B and  9 , to unlock and unset the packer, hydraulic pressure from the setting port  53  pressurizes setting chamber  64  to exert force upon surface  65  of double acting piston  55  and unload ratchets  60  and  61 . Hydraulic pressure from unsetting port  54  then pressurizes the volume between ratchets  60  and  61  forcing locking piston  58  away from the surface of the mandrel  59  and disengaging ratchets  60  and  61 . Plunger valve  62  is sized so that head  100  contacts retaining plate  101  thus opening plunger valve  62  when the ratchets  60  and  61  are disengaged. Upon opening, the plunger valve  62  allows pressurized hydraulic fluid from the unsetting port  54  through bleed port  63  and into unsetting chamber  66 . Unsetting chamber  66  becomes pressurized and exerts force upon surface  67  of double acting piston  55 . Hydraulic pressure from the setting port  53  is gradually reduced so that the force acting upon surface  67  is sufficient to overcome the force acting upon surface  65  and the double acting piston moves back to its running position unsetting the packer. Upon release of hydraulic pressure on the setting port  53  and the unsetting port  54 , the packer is unset. 
     4. Embodiment #4 
     A fourth embodiment of the present invention is capable of being hydraulically set and locked as well as unlocked and unset. Referring now to FIGS. 10A through 10C, this embodiment uses two distinct sources of hydraulic pressure, a setting port  68  (also functions as the locking port) that sets and locks the packer and an unlocking port  69  (also functions as the unsetting port) that unlocks the packer allowing it to unset. These ports are in communication with sources of hydraulic pressure (not shown), which may consist of hydraulic lines extending to the surface, hydraulic accumulators, or other similar devices well known to those skilled in the art. The hydraulic packer of this embodiment is capable of being set/locked and unlocked/unset multiple times without being removed from the well. 
     Referring now to FIGS. 11 and 12A to  12 C, to set and lock the packer of the present embodiment, hydraulic pressure from setting port  68  pressurizes setting chamber  73  thus applying force to surface  74  of locking tackle  75  and surface  76  of setting piston  70  (which also functions as the locking piston). The force applied to surface  74  causes locking tackle  75  to slide and release collet finger  77  of setting piston  70  from groove  102 . Upon release, setting piston  70  moves in a setting direction actuating slips  71  and seal elements  72  in a conventional manner. A wide variety of slip and sealing element configurations are old and well known in the art. As will be appreciated by those skilled in the art, the present embodiment could be modified to function with a variety of other slip and sealing element configurations. It is to be understood that the embodiment described herein includes other slip and sealing element mechanisms that would be known to a skilled artisan. Ratchets  78  on the setting piston  70  engage matching ratchets  79  on the interior of a rotating lock ring  80  thus setting and locking the packer. The rotating lock ring  80  is segmented and held about the setting piston  70  by garter springs  81 . 
     Referring now to FIGS. 12A,  12 B,  13 ,  14 , and  15 , to unlock and unset the packer, hydraulic pressure from setting port  68  pressurizes setting chamber  73  applying force to surface  76  to unload ratchets  78  and  79 . When ratchets  78  and  79  are unloaded, hydraulic pressure from unlocking port  69  pressurizes unlocking chamber  82  applying force to surface  83  of unlocking piston  84  and causing unlocking piston  84  to translate axially in an unlocking direction. Axial translation of unlocking piston  84  is transmitted to annular housing  85  through bearing  86 . Tab  87  is fixedly attached to annular housing  85  and slides within helical groove  88  thus causing annular housing  85  to rotate upon application of axial translation. Connecting rods  89  fixedly attached to annular housing  85  slidably engage lugs  90  to transmit rotation to rotating housing  91 . Tabs (not shown) on rotating housing  91  transmit rotation to detents (not shown) in rotating lock ring  80 . 
     The ratchets  78  and  79  on the setting piston  70  and the rotating lock ring  80  have axial grooves  92  and  93  that allow the ratchets  78  and  79  to disengage when the rotating lock ring  80  is rotated in relation to the setting piston  70 . Likewise, the ratchets  78  and  79  reengage upon rotation of the rotating lock ring  80  to its original position. In the preferred embodiment, there are four sets of axial grooves  92  and  93 . Thus, in this embodiment, the helical groove  88  is designed to turn the rotating lock ring  80  45 degrees with respect to the setting piston  70 . However, one of ordinary skill in the art would readily recognize that more or fewer axial grooves  92  and  93  with a corresponding change in the degree of rotation imparted by the helical groove  88  could be used. Furthermore, one of ordinary skill in the art could readily replace the helical groove  88  with a helical W-groove to allow the rotating lock ring  80  to continue rotating in one direction as it engages and disengages the ratchets  78  and  79 . 
     Upon disengagement of ratchets  78  and  79 , hydraulic pressure from the setting port  68  is released allowing returning means  94  to return setting piston  70  to the running position thus releasing the slips  71  and sealing elements  72 . In the preferred embodiment, returning means  94  is a compression spring. However, said returning means  94  could also consist of application of hydraulic force, actuation by captive gas, Belville washers, or other methods known to a skilled artisan. Setting piston  70  is locked into the running position by interaction of collet finger  77  with groove  95  and locking tackle  75 . Once setting piston  70  is locked in the running position, hydraulic pressure from the unlocking port  69  is released allowing the spring return of annular housing  85  which imparts rotation to rotating lock ring  80  thus reengaging ratchets  78  and  79 . 
     From the preceding description of the preferred embodiments, it is evident that the objects of the invention are attained. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended to be taken by way of illustration and example only and is not to be taken by way of limitation. The spirit and scope of the invention are to be limited only by the terms of the appended claims.