Abstract:
A pressure actuated valve is disclosed which includes a plurality of flow openings, and first and second pistons. The first and second pistons are independently actuatable relative to one another, and are releasable coupled to one another by a release sleeve. The pressure actuated valve also includes a closing sleeve that is operatively coupled to the second piston. In an initial position of the second piston, the closing sleeve covers or blocks the plurality of flow openings. The pressure actuated valve includes a ratchet mechanism coupling the release sleeve to the first piston, the ratchet mechanism being adapted to allow movement of the first piston between its initial position and an intermediate position and back to its initial position while allowing the release sleeve to release the second piston after a predetermined number of cycles of movement of the first piston between its initial position and the intermediate position and back to its initial position. Upon release of the second piston by the release sleeve, the second piston, and the closing sleeve, responsive to the urging of a spring, will move to its final position uncovering the plurality of flow openings. The ratchet mechanism allows for the incremental movement of a release sleeve in response to movements of the first piston. The release sleeve is adapted to open the pressure actuated valve upon movement of the release sleeve through a designated distance.

Description:
FIELD OF THE DISCLOSURE 
       [0001]    The present application relates generally to the field of well completion assemblies for use in a wellbore and, more specifically, to a method and apparatus for opening a pressure actuated valve controlling fluid flow between an annulus and an interior of a production zone within a tubing string in a wellbore. 
       DESCRIPTION OF THE RELATED ART 
       [0002]    Mechanical sleeve valves, such as BJ Services Company&#39;s family of Multi-Service Valves, are used in subterranean wells to provide zone isolation and bore completion control for completion operations such as gravel packing, spot acidizing and fracturing, killing a well, or directing flow from the casing to the tubing in alternate or selective completion operations. In such operations, the sleeve valve provides fluid communication between the tubing string, such as the inner diameter of the valve, and the outside of the valve, such as a well annulus. Typically, mechanical sleeve valves are opened or closed, such as by a shifting tool that is placed within the valve body and manipulated by standard wireline and/or coiled tubing methods. The sleeve, which seals the fluid communication path, can be physically moved from the closed to opened position, and vice versa, by these methods. 
         [0003]    There also exist hydraulically actuated sleeve valves, such as Well Dynamics&#39; CC Interval Control Valve, in which opening and closing of the valve is achieved remotely with the use of one or more hydraulic control lines. In these types of hydraulic sleeve valves, a pressure differential across a defined piston area causes the sleeve to move in the desired direction. 
         [0004]    Other sleeve valves operate by applying or increasing pressure in the downhole bore to unlock the sleeve valve and then bleeding the applied pressure to allow the valve to open using mechanical means, such as a compressed spring, for example. There are times when an operator would like to pressurize and bleed the pressure in the downhole bore without opening the sleeve valve. Currently, one of the methods to accomplish this is to shear pin the valve in the closed position requiring relatively high pressure to shear the pin and open the valve. Any operations requiring the downhole bore to be pressurized prior to opening the valve is limited to a somewhat lower pressure. 
         [0005]    Locking the sleeve valve closed with a shear pin is both inconvenient and hazardous. A possibility of over pressurizing the downhole bore and opening the sleeve valve prematurely always exists. Alternatively, using a shear pin that requires a sufficiently high pressure to avoid premature opening poses a hazard when the downhole bore is pressurized at the high pressure required to shear the pin and unlock the valve. 
         [0006]    What is needed is an improved hydraulic sleeve valve that allows the downhole bore to be pressurized one or more times without premature opening of the sleeve valve and without the hazards presented by the requirement to set the shear pressure a very high level. 
       SUMMARY OF THE DISCLOSURE 
       [0007]    The present disclosure provides a system which allows an operator to pressurize and bleed a downhole bore without premature opening of a sleeve valve and not requiring the use of a mechanical tool to manually shift the valve. In one embodiment, a double ratchet assembly adapted for moving a valve release sleeve in a first direction and preventing movement of the release sleeve in a second direction opposite the first direction includes a release sleeve having an outer diameter and an outer surface; the release sleeve enclosed in and surrounded by an outer housing, the inner diameter of the outer housing being greater than the outer diameter of the release sleeve and forming an annular void between the outer housing and the release sleeve. An upper housing connector is connected to a proximal end of the outer housing adjacent to the release sleeve; a lower housing connector is connected to a distal end of the outer housing adjacent to the release sleeve. A release piston is disposed within the annular void between the outer housing and the release sleeve, the release piston being moveable in the annular void between the upper connector and the lower connector. A first ratchet mechanism having an inner and outer surface, the inner surface of the first ratchet mechanism adapted to selectively engage the release sleeve and a first ratchet carrier having an inner surface adapted to selectively engage the outer surface of the first ratchet mechanism, the first ratchet carrier moving the release sleeve in a first direction in response to the release piston moving in the first direction. A second ratchet mechanism having an inner and outer surface, the inner surface of the second ratchet mechanism adapted to selectively engage the release sleeve and a second ratchet carrier having an inner surface adapted to selectively engage the outer surface of the second ratchet mechanism. The second ratchet mechanism allowing motion of the release sleeve in the first direction, but preventing movement of the release sleeve in a second direction in response to the release piston moving in the second direction. A spring disposed within the annular void and between the upper connector and the release piston biasing the release piston in the second direction. 
         [0008]    In another embodiment, a rotating ratchet assembly adapted for moving a release sleeve in a first direction includes a release sleeve having an outer diameter and an outer and inner surface, and a housing assembly having a proximal end and a distal end, and an inner diameter greater than the outer diameter of the release sleeve, the housing assembly surrounding the release sleeve. A release piston having a proximal end and a distal end is disposed within the housing assembly; the proximal end of the release piston is disposed adjacent to and spaced from a proximal end of the release sleeve. A ratchet mechanism is disposed between the proximal end of the release piston and the proximal end of the release sleeve, the ratchet mechanism adapted to rotate in a direction transverse to a motion of the release piston in response to the motion of the release piston. The ratchet mechanism is adapted to move the release sleeve in a first direction when the ratchet mechanism has rotated through a first predetermined radial angle. A spring is disposed within the annular void between the housing connector and the release piston biases the release piston in a second direction. 
         [0009]    In one embodiment of the present disclosure, a pressure actuated valve (“PAV”) is adapted to be positioned in a subterranean well bore having at least an upper zone and an upper zone pressure. A PAV as described herein includes a plurality of flow openings through the wall of a pipe or tubing, and a first piston and a second piston, wherein the first and second pistons are independently actuatable relative to one another. The PAV also includes a closing sleeve that is operatively coupled to the second piston. The closing sleeve is adapted to be positioned so as to block or not block the plurality of flow openings. In an initial position of the second piston, the closing sleeve covers or blocks the plurality of flow openings. The first piston is movable when a pressure within the valve is greater than an upper zone pressure in the well, while the second piston is movable when the pressure within the valve is approximately equal to or less than the upper zone pressure within the well. The PAV also comprises a first spring positioned proximate the first piston, the first spring being adapted to apply a biasing force to the first piston so as to urge the first piston to move towards its initial position. The first piston is coupled to the second piston by a release sleeve. The valve also includes a plurality of actuatable members, such as spring actuated dogs, that engage the second piston when the first and second pistons are in their initial positions and thereby secure the second piston in its initial position. The second piston is secured in its initial position until unlocked and released by a predetermined number of cycles of reciprocal movement of the first piston. The PAV also comprises a second spring positioned proximate the second piston, the spring being adapted to apply a biasing force to the second piston so as to urge the second piston to move toward a final position so as to uncover the plurality of flow openings. The PAV includes a ratchet mechanism coupling the release sleeve to the first piston, the ratchet mechanism being adapted to allow movement of the first piston between its initial position and the intermediate position and back to its initial position while allowing the release sleeve to release the second piston after a predetermined number of cycles of movement of the first piston between its initial position and the intermediate position and back to its initial position. Upon release of the second piston by the release sleeve, the second piston, and the closing sleeve, responsive to the urging of the second spring, will move to its final position uncovering the plurality of flow openings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]    The following figures, in which like numerals indicate like elements, form part of the present specification and are included to further demonstrate certain aspects of the present application. The present application may be better understood by reference to one or more of these figures in combination with the detailed written description of specific embodiments presented herein. 
           [0011]      FIGS. 1A ,  1 B and  1 C illustrate a cross-sectional side view of a prior art pressure activated control valve in a locked-closed configuration; 
           [0012]      FIGS. 2A ,  2 B and  2 C illustrate a cross-sectional side view of the prior art pressure activated control sleeve valve of  FIGS. 1A ,  1 B and  1 C in an unlocked-closed configuration; 
           [0013]      FIGS. 3A ,  3 B and  3 C illustrate a cross-sectional side view of the prior art pressure activated control valve of  FIGS. 1A ,  1 B and  1 C in an open configuration; 
           [0014]      FIGS. 4A-4E  illustrate a cross-sectional side view of one embodiment of a valve opening mechanism for a pressure actuated sleeve valve in a locked-closed configuration; 
           [0015]      FIGS. 5A-5E  illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an unlocked-closed configuration after a first tubing pressure increase cycle of the embodiment shown in  FIGS. 4A-4E ; 
           [0016]      FIGS. 6A-6E  illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an unlocked-closed configuration after a first tubing pressure bleed cycle of the embodiment shown in  FIGS. 4A-4E ; 
           [0017]      FIGS. 7A-7E  illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an unlocked-closed configuration after a final tubing pressure increase cycle of the embodiment shown in  FIGS. 4A-4E ; 
           [0018]      FIGS. 8A-8E  illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an open configuration after a final pressure bleed cycle of the embodiment shown in  FIGS. 4A-4E ; 
           [0019]      FIG. 9  is a side cross-section view of a double-ended ratchet collet  228  used in one embodiment of a double ratchet mechanism shown in  FIGS. 4A-8E ; 
           [0020]      FIG. 10  is a side cross-section view of a ratchet collet carrier  224  used in conjunction with the double-ended ratchet collet  228  of  FIG. 9 ; 
           [0021]      FIG. 11  is an isometric view of a body lock ring  234  used in one embodiment of a double ratchet mechanism shown in  FIGS. 4A-8E ; 
           [0022]      FIG. 12  is a cross-section view of one embodiment of the outer engaging teeth of the body lock ring  234  that engage the body lock ring carrier  232  and inner teeth that engage the release sleeve  216  shown in  FIGS. 4A-8E ; 
           [0023]      FIG. 13A  is a cross-section view of one embodiment of the outer engaging teeth of the double-ended ratchet collet  228  that engage the ratchet collet carrier  224  and inner teeth that engage the release sleeve  216  shown in  FIGS. 4A-8E ; 
           [0024]      FIG. 13B  is a cross-section view of another embodiment of the release sleeve  216  teeth that engage the inner teeth of the double-ended ratchet collet  228 ; 
           [0025]      FIGS. 14A-14E  illustrate a cross-sectional side view of another embodiment of a valve opening mechanism for a pressure actuated sleeve valve in a locked-closed configuration; 
           [0026]      FIGS. 15A-15E  illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in a locked-closed configuration after a first tubing pressure applied cycle shown in the embodiment of  FIGS. 14A-14E ; 
           [0027]      FIGS. 16A-16E  illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in a locked-closed configuration after a first tubing pressure bleed cycle of the embodiment shown in  FIGS. 14A-14E ; 
           [0028]      FIGS. 17A-17E  illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an unlocked-closed configuration after a final tubing pressure applied cycle shown in the embodiment of  FIGS. 14A-14E ; 
           [0029]      FIGS. 18A-18E  illustrate a cross-sectional side view of the valve opening mechanism for a pressure actuated sleeve valve in an open configuration after a final tubing pressure bleed cycle shown in the embodiment of  FIGS. 14A-14E ; 
           [0030]      FIGS. 19A and 19B  illustrate a top view of the rotating ratchet mechanism of the embodiment shown in  FIGS. 14A-18E . 
       
    
    
       [0031]    These and other embodiments of the present application will be discussed more fully in the following detailed description. The features, functions, and advantages can be achieved independently in various embodiments of the present application, or may be combined in yet other embodiments. The figures and detailed descriptions of these specific embodiments are not intended to delimit all embodiments of the disclosure or to limit the breadth or scope of the described concepts or the appended claims in any manner. Rather, the figures and detailed written descriptions are provided to illustrate the disclosed concepts to a person of skill in the art. 
       DETAILED DESCRIPTION 
       [0032]    One or more illustrative embodiments incorporating the disclosure described herein are presented below. Not all features of an actual implementation are necessarily described or shown for the sake of clarity. For example, the various seals, vents, joints and others design details common to oil well equipment are not specifically illustrated or described. It is understood that in the development of an actual embodiment incorporating the present disclosure, numerous implementation-specific decisions must be made to achieve the developer&#39;s goals, such as compliance with system-related, business-related, government-related, and other constraints, which vary by implementation and from time to time. While a developer&#39;s efforts might be complex and time-consuming, such efforts would be, nevertheless, a routine undertaking for those of ordinary skill in the art having benefit of this disclosure. 
         [0033]    As used within this description, relative and positional terms, such as, but not limited to “up” and “down”, “upward” and “downward”, “upstream” and “downstream”, “upper” and “lower”, “upwardly” and “downwardly”, and other like terms are used in this description to more clearly describe some embodiments of the disclosure. In various ones of the figures, the drawings may be oriented horizontally; in such figures, the left side of the figure is “up” or “uphole” and the right side of the figure is “down” or “downhole.” However, when applied to apparatus and methods for use in wells that are deviated or horizontal, such terms may refer to a “left to right”, “right to left”, or other relationship as appropriate. Also, as used herein the terms “seal” and “isolation” are used with the recognition that some leakage may occur and that such leakage may be acceptable. 
         [0034]    An improved hydraulic sleeve valve for use in subterranean wells is disclosed. The valve comprises a body having a plurality of flow ports allowing communication from outside the body to inside the body. A movable sleeve may be sealed to the inside of the body such that in one position the sleeve prevents flow through the body flow ports and in another position flow therethrough is facilitated. The sleeve may be moved from the closed position to the opened position by a pressure differential which may be applied across one or more pistons associated with the sleeve. The improved sleeve valve comprises a release piston that provides a ratcheting action to unlock the valve as a result of repeated pressure applications to the release piston. The sleeve valve is then opened by a spring-biased valve piston. 
         [0035]    Referring now to  FIGS. 1A-3C , a cross-sectional side view of a prior art pressure actuated control valve  100  (“PAC”). PAC  100  generally comprises an outer housing or tube  101  constructed of several sections. A top connector housing  102  is disposed at the upper end of the PAC  100 . The top connector housing  102  includes an internally threaded portion  104  and a set screw  105  at the top end thereof for receiving and coupling to an externally threaded stub  106 . At the lower end of the top connector housing  102 , the upper end of a release piston carrier  108  is received by an internally threaded portion  110  thereby coupling the release piston carrier  108  to the top connector housing  102 . Housing extension  112  is coupled to the lower end of the release piston carrier  108  and to the upper end of an upper body section  114 . Each end of the housing extension  112  is internally threaded to engage externally threaded portions  113  and  116  at the lower end of the release piston carrier  108  and the upper body section  114 , respectively. A housing lower body section  118  is coupled to the lower end of the upper body section  114  and to the upper end of a lower housing section  120 . The upper and lower ends  115  and  117 , respectively, of the housing lower body section  118  are threaded and are received by corresponding threaded sections of the upper body section  114  and the lower housing section  120 . An externally threaded upper end  121  of a housing connector  122  is received by and coupled to a corresponding internally threaded lower end of lower housing section  120 . The externally threaded lower end  123  of the housing connector  122  is received by an internally threaded upper end of and coupled to a lower cross-over section  124 . 
         [0036]    An inner housing or tube  130  is generally constructed within a lower portion of the outer housing of the PAC  100  and extends upwards from the bottom or lower end of the PAC  100 . An inner housing section  132  is disposed within and concentric with the PAC  100  outer housing  101 . An externally threaded portion of the upper end  134  of the inner housing section  132  is received by and coupled to a corresponding internally threaded portion  136  of the lower housing section  120  and is securely held in position with set screw  135 . The inner housing section  132  is spaced from the outer housing  101 . A number of fluid ports  133  are formed around the circumference of the inner housing section at the upper end of the inner housing  132 . An inner lower connector section  138  is spaced from and disposed within and concentric with the outer housing  101  below the inner housing section  132 . An externally threaded portion of the upper end  140  of the inner lower connector section  138  is received by and coupled to a corresponding internally threaded portion  142  of the inner housing section  132  and is securely held in position with set screw  141 . An annular space is formed between the inner housing  130  and the lower portion of the outer housing  101  which defines a fluid flow path  150  to communicate fluid between the inner housing  130  and the outer housing  101  to the fluid ports  133 . A closing sleeve  144  is slidably disposed within the inner housing  130  adjacent to the inner housing section  132  and extends upwards within the PAC  100 . A portion  146  of the closing sleeve  144  is formed to slide over the fluid ports  133  to completely restrict the flow of fluid through the ports  133  (as shown in  FIGS. 1B and 2B ). The lower portion of the closing sleeve  144  has a number of fluid ports  148  formed through and around the circumference of the closing sleeve  144 . When the closing sleeve  144  is allowed to move in an upwardly direction within the PAC  100  until the closing sleeve fluid ports  148  are aligned with the fluid ports  133 , fluid is allowed to flow from the annular space  150  between the inner housing  130  and the outer housing  101  to the inner bore or tube  151  of the PAC  100 . 
         [0037]    An annular space  152  is formed between the closing sleeve  144  and the lower housing section  120 . A spring  154  is disposed in the lower portion of the annular space  152  and bears against a spring retainer ring  156  held in place by one or more retainer keys  158  inserted in through holes provided in the wall of the lower housing section  120  at the upper end of the inner housing  132 . The upper end of the spring  154  bears against seal retainer ring  160 . A valve piston  162  is disposed in the upper portion of annular space  152  and extends upwardly between the upper end of the closing sleeve  144  and lower and upper housing body sections  118  and  114 , respectively. The lower end of valve piston  162  is internally threaded for receiving the seal retainer ring  160  and coupling it thereto. A piston cap  166  is mounted at the upper end of the valve piston  162  by a threaded portion  167 . The valve piston  162  is secured to the closing sleeve  144  at its upper end by one or more shear screws  164  about the inner circumstance of the valve piston  162 . The closing sleeve  144  is selectively retained in position over the fluid ports  133  by one or more actuatable members, such as spring-biased dogs  168 , for example, mounted in an upper portion of upper body section  114  and extending into slot  170  formed about the outer circumference of the valve piston  162 . A release piston  172  is slidably disposed in annular space  171  formed between the release piston carrier  108  and seal bore connector  174  disposed within and concentric to the PAC  100  outer housing  101 . A release piston lower extension  176  extends downwardly into an annular space  178  formed between housing extension  112  and the upper end of upper body section  114  and piston cap  166 . 
         [0038]    Typically, the PAC  100  is run into a wellbore in a locked-closed configuration, as shown in  FIGS. 1A-1C , wherein the uphole end is on the left of  FIG. 1A  and the downhole end is on the right end of  FIG. 1C . In the locked-closed configuration, the portion  146  of the closing sleeve  144  covers the fluid ports  133 . In the locked-closed configuration, the spring  154  is compressed biasing the valve piston  162  in an upwardly direction. The release piston lower extension  176  covers the spring-biased dogs  168  maintaining them in slot  170  in the valve piston  162  and preventing the valve piston  162 , and thus the closing sleeve  144 , from moving upwards and aligning the sleeve fluid ports  148  with the fluid ports  133 . The release piston lower extension  176  is held in place by one or more shear pins  180  protruding from a portion  182  of the upper end of the upper body housing section  114  and extending through release piston lower extension  176 . 
         [0039]    The PAC  100  may be reconfigured to an unlocked-closed (sheared) configuration, as shown in  FIGS. 2A-2C . The PAC  100  is unlocked by creating a pressure differential between the inner bore or tube  151  of PAC  100  and upper portion of annular space or void  171 . The inner bore  151  is pressurized by pressuring down the wellbore tubing (not shown) coupled to the upper end of the top connector housing  102  via stub  106  at internally threaded portion  104 . Increased pressure is thus asserted against the face  173  of the release piston  172 . Vents  175  and  177  vent the annular space  171  to the exterior of the outer housing  101  creating a pressure differential across the release piston  172  driving the release piston  172  upwards in the annular space  171 . The action of the release piston  172  moving upwards uncovers the release piston snap ring  184  allowing the snap ring  184  to contract slightly into an elongated annular groove  186  and prevent the release piston  172  from moving downwardly when the increased pressure in the inner bore  151  is bled off. As the release piston  172  moves upwardly, the release piston lower extension  176  shears the shear pins  180  and uncovers the spring-biased dogs  168 . When the dogs  168  are uncovered, a spring, such as a leaf spring, for example, forces the dogs  168  outwardly and out of the slot  170  and the closing sleeve  144  is free to slide upwardly. As long as increased pressure is maintained in the inner bore  151 , pressurized fluid bears against the face  179  of the piston cap  166  preventing the closing sleeve from sliding upwardly and opening the fluid ports  133 . 
         [0040]      FIGS. 3A-3C  illustrate the PAC  100  in an open configuration, wherein the uphole end is on the left and the downhole end is on the right. The valve is opened by bleeding, i.e., reducing, the pressure in the inner bore  151 . When the inner bore pressure is bled off, the compressed spring  154  expands against the lower end of the valve piston  162  pushing the valve piston  162 , and thus the closing sleeve  144 , upwardly until the closing sleeve fluid ports  148  are aligned with the fluid ports  133  allowing fluid to flow from the annular space  150  between the inner housing  130  and the outer housing  101  to the inner bore or tube  151  of the PAC  100 . 
         [0041]    Referring now to  FIGS. 4A-8E , a cross-sectional side view of one embodiment of a valve opening mechanism for a pressure actuated sleeve valve  200  (“PAV”) according to the present disclosure is shown. The construction and operation of the PAV  200  is similar to the construction and operation of the PAC  100  described above. The PAV  200  valve opening mechanism and operation allows the fluid pressure in the inner bore or tube to be increased and decreased (bled) for several cycles, for example five cycles, prior to opening the valve. In contrast, the opening mechanism and operation of PAC  100  opened the valve at the end of a single pressurize and bleed cycle. 
         [0042]    PAV  200  generally comprises an outer housing or tube  201  constructed of several housing and connecting sections. A top connector housing  202  is disposed at the upper end of the PAV  200 . The upper or uphole end of the PAV  200  is on the left and the lower or downhole end is on the right as shown in the various figures. The top connector housing  202  includes a coupling portion at its top end (not shown) for receiving and coupling to uphole tubing or other components such as portions of an isolation string (not shown). At the lower end of the top connector housing  202 , the upper end of upper body connector  204  is received by an internally threaded portion  203  thereby coupling the upper body connector  204  to the top connector housing  202 . Release piston housing  206  is coupled to the lower end of the upper body connector  204  and to the upper end of a lower body connector  208 . Housing extension  210  is coupled to the lower end of the lower body connector  208  and to the upper end of an upper body section  214 . Each end of the housing extension  210  is internally threaded to engage externally threaded portions  211  and  213  at the lower end of the lower body connector  208  and the housing upper body section  214 , respectively. The lower section of PAV  200  below housing upper body section  214  is similar to the lower section of PAC  100  below housing upper body section  114 . 
         [0043]    As described above with reference to  FIGS. 1A-3C , a closing sleeve  144  covers fluid ports  133  and has a number of fluid ports  148  formed through and around the circumference of the closing sleeve  144  below the fluid ports  133 . To open the valve, the closing sleeve  144  is allowed to move in an upwardly direction within the valve body until the closing sleeve fluid ports  148  are aligned with the fluid ports  133 . The closing sleeve  144  is secured to the valve piston  162  at its upper end by one or more shear screws  164  about the inner circumstance of the valve piston  162 . A piston cap  166  is mounted at the upper end of the piston valve  162  by threaded portion  167 . The closing sleeve  144  is retained in position covering the fluid ports  133  by one or more actuatable members, such as spring-biased dogs  168 , for example, mounted in an upper portion of upper body section  214  and extending into slot  170  formed about the outer circumference of the valve piston  162 . A release sleeve  216  is slidably disposed within and concentric to outer housing  201 . A release sleeve extension  217  extends into annular space  218  formed between housing extension  210 , and piston cap  166  and an upper end portion  220  of upper body section  214 . The release sleeve extension  217  covers and extends a predetermined distance, several inches, for example, below the spring-biased dogs  168  preventing the dogs  168  from retracting from slot  170 . 
         [0044]    A release piston  222  is slidably disposed within the annular space formed between the release sleeve  216 , and lower body connector  208  and release piston housing  206 . A ratchet carrier  224  near the upper end of release piston  222  includes ratchet teeth  225  formed around at least a portion of the surface of the inner circumference of the ratchet carrier  224 . The ratchet carrier  224  may be formed integrally with the release piston  222  or may be a separate component fixed or fastened to the upper end of release piston  222 . A double-ended ratchet collet  228  is placed between the release piston  222  and the release sleeve  216  concentric to and surrounding the release sleeve  216  for at least a portion of the outer circumference. The double-ended ratchet collet  228  is attached to a collet holder  229  between the release piston  222  and the release piston retainer ring  226  by set screw  237 , for example. Ratchet teeth  227  formed on the outer surface double-ended ratchet collet  228  opposite the ratchet carrier  224  engage the ratchet teeth  225  formed in the inner surface of the ratchet carrier  224 . As shown in  FIGS. 9 ,  13 A and  13 B, teeth  901  formed on the inner surface of double-ended ratchet collet  228  engage teeth or shaped slots  1301  formed on the outer surface of release sleeve  216 . A spring  230  is disposed in the annular space formed between the release sleeve  216  and release piston housing  206 . The upper end of spring  230  bears against the lower end face  231  of upper body connector  204  while the lower end of spring  230  bears against release piston retainer ring  226  biasing the release piston  222  in a downwardly direction. A body lock ring carrier  232  at the lower end of upper body connector  204  includes ratchet teeth  233  formed in the inner surface for at least a portion of the inner circumference of the body lock ring carrier  232 . A body lock ring  234  is placed between the release piston  222  and the release sleeve  216  concentric to and surrounding the release sleeve  216  for at least a portion of the outer circumference of the release sleeve  216 . Ratchet teeth  235  formed on the outer surface of body lock ring  234  opposite the body lock ring carrier  232  engage the ratchet teeth  233  formed in the inner placed between the release piston  222  and the release sleeve  216  concentric to and surrounding surface of the body lock ring carrier  232 . As shown in  FIGS. 11 and 12 , teeth  1101  formed on the inner surface of body lock ring  234  engage teeth  1201  formed on the outer surface of release sleeve  216 . 
         [0045]    Typically, the PAV  200  is run into a wellbore in a locked-closed configuration, as shown in  FIGS. 4A-4E . In the locked-closed configuration, the closing sleeve  144  covers the fluid ports  133 , and the spring  154  is compressed biasing the valve piston  162  in an upwardly direction. The release sleeve extension  217  covers the spring-biased dogs  168  maintaining them in slot  170  in the valve piston  162  and preventing the valve piston  162 , and thus the closing sleeve  144 , from moving upwards. The release sleeve extension  217  is held in place by one or more shear pins  180  protruding from a portion  221  of the upper end  220  of the upper body housing section  214  and extending through the release sleeve extension  217 . 
         [0046]    The PAV  200  may be reconfigured to an unlocked-closed (sheared) configuration, as shown in  FIGS. 5A-5E . The PAV  200  is unlocked by creating a pressure differential across the release piston  222  between the annular space or void  236  formed between the release sleeve  216  and lower body connector  208 , and the annular space or void  238  formed between the release sleeve  216  and the release piston housing  206 . The inner bore  251  of PAV  200  is pressurized by pressuring down the wellbore tubing (not shown) coupled to the upper end of the top connector housing  202 . Fluid from the inner bore  251  bleeds into annular space  236  through orifices (not shown) provided in the release sleeve  216  at the corner where the release sleeve  216  joins the release sleeve extension  217  asserting increased pressure against the face  240  of release piston  222 . Vents (not shown) vent the annular space  238  to the annular area formed between the outer housing  201  and the upper body connector  204  creating a pressure differential across the release piston  222  driving the release piston  222  upwards in the annular space  238  compressing spring  230  against the face  231  of upper body connector  204 . As the release piston  222  moves upwards, the ratchet carrier  224  and the double-ended ratchet collet  228  moves in an upwardly direction. As the release piston  222  moves upwardly, the double-ended ratchet collet  228  is forced against the release sleeve  216  such that the teeth  901  formed on the inner surface of double-ended ratchet collet  228  engage teeth  1301  formed on the outer surface of release sleeve  216  moving the release sleeve  216  upwards along with the release piston  222 . In addition, as the release sleeve  216  is pulled upwards by the movement of the release piston  222 , the body lock ring  234  teeth  1101  slide over the teeth  1201  formed on the outer surface of the release sleeve  216 . The release piston  222  moves upwardly a predetermined distance, stopping its upward movement when upper end of the release piston retainer ring  226  contacts and butts against the lower end face  231  of upper body connector  204 . As the release sleeve  216  moves upwards, the release sleeve extension  217  slides upwardly a portion of the distance that it extends in the annular space  218  past the spring-biased dogs  168  shearing the shear pin  180 . Since the release sleeve extension  217  has only moved a portion of the distance it extends past the spring-biased dogs  168 , the dogs  168  remain covered by the release sleeve extension  217  thus preventing any upward movement of the closing sleeve  144 . 
         [0047]    When the fluid pressure in the PAV  200  inner bore  251  is reduced, the fluid pressure against face  240  of the release piston  222  bleeds off reducing the pressure differential across the release piston  222 . The reduced pressure differential allows spring  230  drive the release piston  222  downwards its original unpressurized position against the upper face  242  of lower body connector  208 . The downward motion of the release piston  222  allows the teeth  901  of ratchet collet  232  to slide over the teeth  903  of release sleeve  216  while the release sleeve body lock ring  234  teeth  1101  engage the teeth  1201  of release sleeve  216  preventing any downward movement of the release sleeve  216  as shown in  FIGS. 6A-6E . For each additional pressurize and bleed cycle, the release sleeve  216 , and hence the release sleeve extension  217  will move upwards an additional predetermined distance. The distance the release sleeve  222  moves each pressurize/bleed cycle is determined by the distance  244  separating the upper end  246  of the release piston retainer ring  226  and the lower end face  231  of upper body connector  204 . The distance  244  is determined by the width of the spring-biased dogs  168 . In one embodiment, the release piston  222  moves upward about three-quarters of one inch for each pressurize/bleed cycle. The next to the last pressure/bleed cycle must leave the spring-biased dogs  168  completely covered and the last pressure/bleed cycle must completely uncover the spring-biased dogs  168 . In one embodiment, five pressurize/bleed cycles are required to uncover the spring-biased dogs  168 . To ensure that the release sleeve  216  moves substantially the same distance for each pressure/bleed cycle, the double-ended ratchet collet  228  teeth  901  are widely spaced so that the double-ended ratchet collet  228  catches one and only one additional tooth  1301  on the release sleeve  216  outer surface for each pressure/bleed cycle. 
         [0048]      FIGS. 7A-7E  illustrate the PAV  200  configuration after the last pressurize cycle. The release sleeve  216  has now been moved upwards a sufficient distance to withdraw the release sleeve extension  217  from the annular space  218  to uncover the spring-biased dogs  168 . Once uncovered, the spring-biased dogs  168  are retracted from slot  170 , such as by the action of a leaf spring, for example, in the valve piston  162 . Fluid pressure on the face  179  of piston cap  166  overrides the compressed spring  154  preventing the closing sleeve  144  from sliding upwardly and opening the fluid ports  133 . 
         [0049]    The PAV  200  is opened by bleeding, i.e., reducing, the pressure in the inner bore  251  as shown in  FIGS. 8A-8E . When the inner bore pressure is bled off, the compressed spring  154  expands against the lower end of the valve piston  162  pushing the valve piston  162 , and thus the closing sleeve  144 , upwardly until the closing sleeve fluid ports  148  are aligned with the fluid ports  133  opening the valve. 
         [0050]    Referring now to  FIG. 9 , an isometric view, wherein arrow  911  indicates the upwards or uphole direction and arrow  913  indicates the downwards or downhole direction, of a double-ended ratchet collet  228  of one embodiment of the present disclosure is shown. The double-ended ratchet collet  228  includes longitudinal collet segments  903  separated by longitudinal slots  905  located around the circumference of the collet. The number and width of the longitudinal collet segments  903  may be varied depending on the application using the double ratchet mechanism. The interior surface of each collet segment  903  includes teeth  901  that are adapted to selectively engage the teeth  1301  formed on the outer surface of release sleeve  216 . The teeth  1301  form a thread, such as a buttress thread, for example, around the outside diameter of release sleeve  216 . Teeth  901  are relatively widely spaced to ensure that only one additional tooth  1301  is picked up for each additional pressurize/bleed cycle. The exterior surface of each collet segment  903  includes teeth  227  to engage with the teeth  225  formed in the inner surface of the ratchet carrier  224 . 
         [0051]    Referring now to  FIG. 10 , one embodiment in accordance with the present disclosure of a ratchet collet carrier  224  is shown. The ratchet collet carrier  224  includes teeth  225  on the interior or inner surface, the teeth  225  being adapted to engage with the teeth  227  located on the collet fingers  903 . Openings  1001  around the perimeter of the ratchet collet carrier  224  may be used in one embodiment to secure the ratchet collet carrier  224  to the upper end of the release piston  222  by locking pins or set screws (not shown), for example. In some embodiments, a locking pin (not shown), for example, may be inserted through slot  1002  formed around the perimeter of the ratchet collet carrier  224  into a receiving slot (not shown) formed in the outside surface of ratchet collet  228  to prevent any relative rotation between ratchet collet carrier  224  and ratchet collet  228 . 
         [0052]    Referring now to  FIG. 11 , an isometric view of a body lock ring  234  of one embodiment of the present disclosure is shown. The interior surface of the body lock ring  234  includes teeth  1101  that are adapted to selectively engage the teeth  2101  formed in the outer surface of release sleeve  216 . The body lock ring  234  includes a gap  1103  the formed in the body. The gap  1103  allows the body lock ring  234  to expand as it ratchets over the teeth  1201  on the release sleeve  216  (as shown in greater detail in  FIG. 12 ). The gap  1103  aids in the selective engagement of teeth  1101  with teeth  1201  of the release sleeve  216 . The exterior or outer surface of the body lock ring  234  includes teeth  235  adapted to engage with the teeth  233  formed on the inner surface of body lock ring carrier  232 . The body lock ring  234  may include openings  1105  around the perimeter to aid in connecting the body lock ring  234  to the body lock ring holder  241  using locking pins or set screws (not shown), for example. Body lock rings are typically fabricated with the inner diameter small enough such that the inner threads clamp onto a mandrel such as the threaded portion of the release sleeve  216 , for example. 
         [0053]    Referring now to  FIG. 12 , a cross-sectional view of the teeth of the body lock ring  234  according to one embodiment of the present disclosure is shown. The exterior surface of the body lock ring  234  includes teeth  235  that are adapted to engage the teeth  233  of the body lock ring carrier  232 . The body lock ring carrier  232  may be constructed similarly to ratchet collet carrier  224  as shown in  FIG. 10 . The interior surface of the body lock ring  234  includes teeth  1101  that are adapted to engage the teeth  1201  on the outer surface of the release sleeve  216 . When pressure is applied moving the release piston  222  upwards carrying the release sleeve  216  with it, an angle substantially less than 90 degrees for the upwards face  1203  of the teeth  1201  allows the release sleeve  216  to move in an upwards direction, as shown by arrow  1207  sliding past the body lock ring  234 . As the release sleeve  216  moves upward, as shown by arrow  1217 , the body lock ring  234  is forced outwardly towards the body lock ring carrier  232 , the substantially 90 degree face  1209  of the teeth  235  on the outer surface of the body lock ring  234  engaging an opposing substantially 90 degree face  1211  of the teeth  233  on the interior surface of the body lock ring carrier  232 . When pressure on the release piston  222  is bled, i.e., reduced, the spring  230  forces the release piston  222  in a downwards direction. Any corresponding downwards motion of the release sleeve  216 , as shown by the arrow  1215 , is prevented by a substantially 90 degree face  1205  of the release sleeve teeth  1201  engaging with an opposing substantially 90 degree face  1213  of the teeth  1101  formed on the interior surface of the body lock ring  234 . Thus the body lock ring  234  acts to allow an upwards motion of the release sleeve  216  but prevents any downwards motion to return the release sleeve  216  to its original position. Conventional body lock rings, and corresponding body lock ring carriers, have a 90 degree face on both the inner and outer face. However, the 90 degree angles may actually only be about 85 degrees to allow the body lock ring, and corresponding body lock ring carrier, to be manufactured more easily. The body lock ring  234  in conjunction with the body lock ring carrier  223  of the present disclosure will allow the release sleeve to ratchet in one direction  1217  and will prevent movement of the release sleeve  216  when it is pushed in the other direction  1215 . 
         [0054]    Referring now to  FIG. 13A , a cross-section view of one embodiment of the outer engaging teeth  227  of the double-ended ratchet collet  228  that engage the teeth  225  of the ratchet collet carrier  224  and inner teeth  901  that engage the shaped slots  1301  formed in the surface of the release sleeve  216  is shown. When pressure is applied moving the release piston  222  upwards carrying the release sleeve  216  with it, as shown by arrow  1319 , an angle substantially less than 90 degrees for the downwards face  1305  of the ratchet collet carrier  224  teeth  225  engages the downwards face  1303  of the double-ended ratchet collet  228  teeth  227  forcing the collet fingers  903  inwardly against the outer surface of the release sleeve  216 . The substantially 90 degree upwards face  1307  of teeth  901  formed on the inner surface of ratchet collect  228  engage the substantially 90 degree face  1309  of shaped slots  1301  formed on the outer surface of release sleeve  216  pulling the release sleeve  216  upwards, as shown by arrow  1319 , as the release piston  222  is forced upwards. When pressure on the release piston  222  is bled, i.e., reduced, the spring  230  forces the release piston  222  in a downwards direction as shown by arrow  1321 . The substantially 90 degree upwards face  1311  of the ratchet collet carrier  224  teeth  225  engage the substantially 90 degree face  1313  of the ratchet collect  228  outer teeth  227  pulling the double-ended ratchet collet  228  in a downwards direction. Since the release sleeve  216  is prevented from moving in a downwards direction by the locking action of the body lock ring  234  engaging the release sleeve  216  teeth  1201 , an angle substantially less than 90 degrees for the both downwards face  1315  of the ratchet collet carrier  224  inner teeth  901  and the downwards face  1317  of the shaped slot  1301  formed in the surface of the release sleeve allows the ratchet collet fingers  903  to expand outwardly pulling the double-ended ratchet collet  228  inner teeth  901  away from the release sleeve surface and out of the shaped slots  1301 . 
         [0055]    Referring now to  FIG. 13B , as will be appreciated by those of skill in the art, in another embodiment of the present disclosure the shaped slots  1301  formed in the surface of the release sleeve  216  may be teeth  1327  protruding from the outer surface of the release sleeve  216  adapted to engage the inner teeth  901  of the double-ended ratchet collet  228 . When pressure is applied moving the release piston  222  upwards carrying the release sleeve  216  with it, as shown by arrow  1319 , the substantially 90 degree upwards face  1307  of teeth  901  formed on the inner surface of ratchet collect  228  engage the substantially 90 degree downwards face  1323  of teeth  1327  formed on the outer surface of release sleeve  216  pulling the release sleeve  216  upwards, as shown by arrow  1319 . When pressure on the release piston  222  is bled, i.e., reduced, the spring  230  forces the release piston  222  in a downwards direction as shown by arrow  1321 . Since the release sleeve  216  is prevented from moving downwards by the locking action of the body lock ring  234  engaging the release sleeve  216  teeth  1201 , as the release piston  222  pulls the double-ended ratchet collet  228  downwards, an angle substantially less than 90 degrees for the both the downwards face  1315  of the ratchet collet carrier  224  inner teeth  901  and the upwards face  1325  of the teeth  1327  formed in the surface of the release sleeve  216  allows the ratchet collet fingers  903  to expand outwardly pulling the double-ended ratchet collet  228  inner teeth  901  away from the release sleeve surface allowing the ratchet collet inner teeth  901  to slide over the release sleeve teeth  1327 . 
         [0056]    Referring now to  FIGS. 14A-18E , a cross-sectional side view of another embodiment of a valve opening mechanism for a pressure actuated sleeve valve  300  (“PAV”) according to the present disclosure is shown. The construction and operation of the PAV  300  is similar to the construction and operation of the PAC  100  described above. Similar to PAV  200 , described above, the PAV  300  valve opening mechanism and operation allows the fluid pressure in the inner bore or tube to be increased and decreased (bled) for several cycles, for example five cycles, prior to opening the valve. 
         [0057]    PAV  300  generally comprises an outer housing or tube  301  constructed of several housing and connecting sections. A top connector housing  302  is disposed at the upper end of the PAV  300 . The upper or uphole end of the PAV  300  is on the left and the lower or downhole end is on the right as shown in the various figures. The top connector housing  302  includes a coupling portion at its top end for receiving and coupling to uphole tubing (not shown) or other components such as portions of an isolation string (not shown). At the lower end of the top connector housing  302 , the upper end of a release piston carrier  308  is received by an internally threaded portion  306  thereby coupling the release piston carrier  308  to the top connector housing  302 . Housing extension  312  is coupled to the lower end of the release piston carrier  308  and to the upper end of an upper body section  314 . Each end of the housing extension  312  is internally threaded to engage externally threaded portions  311  and  313  at the lower end of the release piston carrier  308  and the housing upper body section  314 , respectively. The lower section of PAV  300  (not shown) below housing upper body section  314  is similar to the lower section of PAC  100  below housing upper body section  114 . 
         [0058]    As described above, a closing sleeve  144  covers fluid ports  133  and has a number of fluid ports  148  formed through and around the circumference of the closing sleeve  144  below the fluid ports  133 . To open the valve, the closing sleeve  144  is allowed to move in an upwardly direction within the valve body until the closing sleeve fluid ports  148  are aligned with the fluid ports  133 . The closing sleeve  144  is secured to the valve piston  162  at its upper end by one or more set screws  164  about the inner circumstance of the valve piston  162 . A piston cap  166  is mounted at the upper end of the piston valve  162  by threaded portion  167 . The closing sleeve  144  is retained in position covering the fluid ports  133  by one or more actuatable members, such as spring-biased dogs  168 , for example, mounted in an upper portion of upper body section  314  and extending into slot  170  formed about the outer circumference of the valve piston  162 . A release piston  317  is slidably disposed within annular space  320  formed between the release piston carrier  308  and inner adapter  324 , respectively, and inner sleeve  322  Inner adapter  324  is disposed within and concentric to top connector  302 , and is coupled to top connector  302  by set screws  326  or other suitable coupler. The lower end of inner adapter  324  is coupled to the upper end of release piston carrier  308  at threaded portion  329 . Inner sleeve  322  is coupled to the inner adapter  324  at threaded portion  328 . A spring  321  disposed in the annular space  323  formed between the release piston  317  and housing extension  312  bears against the upper face  325  of release piston  317  and the lower face  319  of release piston carrier  308 . A release sleeve  316  extends into annular space  318  formed between housing extension  312  and piston cap  166 . The lower end  330  of release sleeve  316  covers the spring-biased dogs  168  preventing the dogs  168  from retracting from slot  170 , preventing the closing sleeve from moving upwards in the valve body. The release sleeve  316  is held in place by shear pin  180  extending through release sleeve  316  into piston cap  166 . 
         [0059]    The upper end  332  of release sleeve  316  extends into annular space  334  formed between housing extension  312  and release sleeve extension  336  extending from the lower face  338  of release piston  317 . A rotating ratchet mechanism  340  is disposed between the release sleeve upper end  332  and the release piston extension  336  and is adapted to rotate in a radial direction about the release piston extension  336 . A mounting bracket  342  slidably mounts rotating ratchet mechanism  340  to release piston extension  336  allowing the release piston extension  336  to move upwardly or downwardly as the release piston  317  moves upwardly or downwardly in annular space  320  while also allowing the rotating ratchet mechanism  340  to rotate about release piston extension  336  between release piston  336  and release sleeve upper end  332 . 
         [0060]    Referring now also to  FIGS. 19A and 19B , a top view of the rotating ratchet mechanism  340  is shown. Two annular toothed rings  344  and  346  are fixed in opposing fashion in an annular case  350 . Annular case  350  is rotatably mounted to the release piston extension  336  by mounts  342 . Upper annular ring  344  is fixedly mounted to the uphole or upwards wall  343  of annular case  350  and comprises a number of teeth  345  formed in the annular ring at a predetermined pitch. Similarly, lower annular ring  346  is fixedly mounted to the downhole or downwards wall  341  of annular case  350  and comprises a number of teeth  347  formed in the annular ring at the same pitch and opposing the teeth  345  formed in upper annular ring  344 . Stops  348  are also formed at regular intervals, such as every five teeth, for example, between the teeth  347  of lower annular ring  346 . Lugs  352  formed on the inner surface of and at predetermined intervals about the inner circumference of release sleeve upper end  332  are adapted to mesh and engage teeth  345  and  347  formed on annular rings  344  and  346 , respectively. Lugs  352  may be an integral part of the release sleeve upper end  332  or may be separate components fixedly attached to the release sleeve upper end  332 . 
         [0061]    A pressure increase in the tubing inner bore  351  will force the release piston  317  in an upwards direction moving the rotating ratchet mechanism  340  in an upwards direction engaging the fixed lugs  352 . Since the release sleeve  316  is held in position by shear screw  180 , the lugs  352  remain stationary as the rotating ratchet mechanism  340  moves. As the rotating ratchet mechanism  340  moves in an upwards direction, as indicated by arrow  353 , the angled face  354  will engage the similarly angled face  360  of teeth  345  or of stop  348  causing the ratchet mechanism  340  to rotate a predetermined amount, such as about 18 degrees, for example, in the direction indicated by arrow  357 . Bleeding or reducing the pressure in tubing inner bore  351  allows pressure from the exterior of the valve and the compressed spring  321  to force the release piston  317  downwards moving the rotating ratchet mechanism  340  in a downwards direction. As the rotating ratchet mechanism  340  moves downwards, as indicated by arrow  355 , the angled face  358  of lugs  352  will engage the similarly angled face  356  of teeth  345  causing the ratchet mechanism  340  to further rotate approximately the same amount, such as about 18 degrees, for example, in the same direction as indicated by arrow  357 . 
         [0062]    Typically, the PAV  300  is run into a wellbore in a locked-closed configuration, as shown in  FIGS. 14A-14E . In the locked-closed configuration, the closing sleeve  144  covers the fluid ports  133 , and the spring  154  is compressed biasing the valve piston  162  in an upwardly direction. The release sleeve extension  330  covers the spring-biased dogs  168  maintaining them in slot  170  in the valve piston  162  and preventing the valve piston  162 , and thus the closing sleeve  144 , from moving upwards. The release sleeve  316  is held in place by shear pin  180  extending through release sleeve extension  330  into piston cap  166 . The lugs  352  are positioned at the upper extent of the release piston downwards travel in the valve and are engaged with the teeth  345  against the upper annular ring  344 . 
         [0063]    The PAV  300  may be reconfigured to an unlocked-closed (sheared) configuration, as shown in  FIGS. 17A-17E . The PAV  300  is unlocked by repeatedly pressurizing and then bleeding the pressure in the tubing inner bore  351 . Increasing the pressure in the inner bore  351  creates a pressure differential across the release piston  317  between the tubing inner bore  351  and the annular space or void  320  formed between the inner sleeve  322  and inner adapter  324 , and the annular space or void  323  formed between the release piston  317  and the housing extension  312 . The inner bore  351  of PAV  300  is pressurized by pressuring down the wellbore resulting in increased pressure against release piston  317  face  338  and release piston extension stop  337 . Vents (not shown) vent the annular space  323  to the annular space created between top connector housing  302  and inner adapter  324  (which in turn is vented to the exterior of the valve) creating a pressure differential across the release piston  317  driving the release piston  317  upwards in the annular spaces  320  and  323  and compressing spring  321  against the face  319  of release piston carrier  308 . In some embodiments, the annular space created between top connector housing  302  and inner adapter  324  may be vented to the zone above. Space  320  is vented to the tubing inner bore  351  through the annular space formed between the release piston  317  and the inner sleeve  322 . As the release piston  317  is pushed upwards, the rotating ratchet mechanism  340  moves upwards, as indicated by arrow  353 , and the angled face  354  of lugs  352  will engage the similarly angled face  356  of teeth  347  or stop  348  causing the ratchet mechanism  340  to rotate a predetermined amount, such as about 18 degrees, for example, in the direction indicated by arrow  357 . The release piston  317  will be forced upwards compressing spring  321  until the release piston upper end  362  abuts the face  364  of inner adapter  324  as shown in  FIGS. 15A-15E . 
         [0064]    Bleeding or reducing the pressure in tubing inner bore  351  allows pressure from the valve exterior and the compressed spring  321 to force the release piston  317  downwards moving the rotating ratchet mechanism  340  downwards. As the rotating ratchet mechanism  340  moves downwards, as indicated by arrow  355 , the angled face  358  of lugs  352  will engage the similarly angled face  356  of teeth  345  causing the ratchet mechanism  340  to further rotate approximately the same amount, such as about 18 degrees, for example, in the same direction as indicated by arrow  357 . At the end of the first pressurize/bleed cycle, the release piston  317  will return to its original position, as shown in  FIGS. 16A-16E , while the release sleeve  316  remains in its original locked position covering the spring-biased dogs  168 . The rotating ratchet mechanism  340  has been rotated the angular equivalent of one full tooth width now engaging the lugs  352  by the tooth immediately adjacent to the tooth originally engaging the lugs  352 . With each additional pressurize/bleed cycle, rotating ratchet mechanism  340  will rotate one additional tooth width. At the end of the next to the last pressurize/bleed cycle, the annular rings  344 ,  346  will have rotated a sufficient amount to place the lug stops  348  opposite the lugs  352 , as shown in  FIG. 19B . On the next, and last, pressurize cycle, as the release piston  317  is driven upwards, the face  365  of the lug stops  348  will impact the lugs  352 . As the release piston  317  continues to move upwards, the release sleeve  316  is forced upwards, withdrawing the release sleeve extension  330  shearing the shear pin  180  and uncovering the spring-biased dogs  168  allowing the dogs  168  to retract from slot  170  in the valve piston  162 . As long as the tubing inner bore  351  remains pressurized, fluid pressure on the face  179  of piston cap  166  overrides the compressed spring  154  preventing the closing sleeve  144  from sliding upwardly and opening the fluid ports  133 . 
         [0065]    In the above description, the rotating ratchet mechanism  340  is rotatably attached to the outer surface of the release piston extension  336  adjacent to the release sleeve upper end  332  while the lugs  352  are formed in and extend inwardly from the inner surface of the release sleeve upper end  332  to mesh with the rotating ratchet mechanism  340  teeth  344 ,  346 . In this configuration, the rotating ratchet mechanism  340  moves in an upwards and downwards direction in response to the upwards and downwards movement of the release piston  317 , as shown by the arrows  353  and  355 , respectively, while the lugs remain stationary with respect to the release sleeve  316 . As will be appreciated by those of skill in the art, in another embodiment, rotating ratchet mechanism  340  may be rotatably attached to the release sleeve upper end  332  remaining stationary and not moving in an upwards or downwards direction in response to the movement of the release piston  317 . The lugs  352  are formed in the outer surface of the release piston extension  336  and extend outwardly from the outer surface of the release piston extension  336  to mesh with the rotating ratchet mechanism  340  teeth  344 ,  346 . In this embodiment, the lugs  352  move in an upwards and downwards direction in response to the upwards and downwards, as shown by arrows  353  and  355 , respectively, motion of the release piston  317 . 
         [0066]      FIGS. 17A-17E  illustrate the PAV  300  configuration after the last pressurize cycle. The PAV  300  is shown in the unlocked-closed configuration. Fluid pressure on the face  179  of piston cap  166  overrides the compressed spring  154  preventing the closing sleeve  144  from sliding upwardly and opening the fluid ports  133   
         [0067]    PAV  300  is opened by bleeding, i.e., reducing, the pressure in the inner bore  351  as shown in  FIGS. 18A-18E . When the inner bore  351  pressure is bled off, the compressed spring  154  expands against the lower end of the valve piston  162  forcing the valve piston  162 , and thus the closing sleeve  144 , upwardly until the closing sleeve fluid ports  148  are aligned with the fluid ports  133  opening the valve. When the closing sleeve fluid ports  148  are aligned with the fluid ports  133 , fluid is able to flow from outside the outer housing  101  via fluid flow path  150  formed between the inner housing  130  and the outer housing  101  through the fluid ports  133  to the tubing inner bore  351 . 
         [0068]    While the methods and apparatus of this invention have been described in terms of various embodiments, it will be apparent to those of skill in the art that variations may be applied to the methods, apparatus and/or processes, and in the steps or in the sequence of steps of the methods described herein without departing from the concept and scope of the invention. More specifically, it will be apparent that certain features which are both mechanically and functionally related may be substituted for the features described herein while the same or similar results would be achieved. All such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope and concept of the invention.