You are an expert at summarizing long articles. Proceed to summarize the following text:

You are an expert at summarizing long articles. Proceed to summarize the following text: 
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The invention relates generally to hydraulic switches used to control the actuation of multiple pressure controlled devices within a wellbore. 
         [0003]    2. Description of the Related Art 
         [0004]    It is common in downhole wellbore production systems to employ sliding sleeve valves, safety valve or chemical injection valves that use hydraulic pressure control for actuation. Each of these pressure controlled devices (“PCD”s) uses a pair of hydraulic control lines—an inflow line and an outflow line. In a number of instances, it is desired to have multiple PCDs within a borehole. Because each PCD uses two control lines, this means that a large number of control lines that must be run into the wellbore. The inventor has realized that there are a number of significant advantages to being able to reduce the number of control lines that are run into a wellbore. The reduction of control lines results in a direct reduction in cost due to the reduced amount of control line that must be run into the wellbore. In addition, there are indirect savings, particularly in deepwater wells, as there are fewer lines that require a dedicated feed through in the subsea tree and dedicated umbilicals back to the surface. Moreover, each additional control line that is used in a wellbore requires dedicated pressure testing and time. Further, a reduced number of control lines results in a more reliable system since the number of potential leak paths is reduced. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention provides systems and methods for operating multiple hydraulic PCDs within a borehole using a common inflow and outflow line and a common cycling line. In preferred embodiments, the PCDs comprise sliding sleeve valve devices which are used to control flow of production fluid into the production string of a wellbore. In a preferred embodiment, a control system is used wherein each of the PCDs is operationally associated with a separate sleeve controller. The sleeve controller for each PCD controls whether the individual PCD can be actuated by hydraulic pressure variations in the common inflow and outflow lines. 
         [0006]    In a currently preferred embodiment, each sleeve controller includes an outer housing that defines an interior chamber. A piston member is moveably disposed within the chamber. Movement of the piston member with respect to the surrounding chamber is controlled by a J-slot lug mechanism. The J-slot lug mechanism causes the piston member to be moved between a first position wherein the corresponding PCD can be actuated by the inflow/outflow lines and a second position wherein the corresponding PCD is unable to be actuated by the inflow/outflow lines. Movement of the piston member within the sleeve controller is preferably done by selective pressurization of the cycling line. 
         [0007]    In operation, the control system can be operated in a step-wise manner to move the sleeve controllers for each PCD are moved sequentially through a series of positions which afford operational control of selected PCDs in accordance with a predetermined scheme. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]    For a thorough understanding of the present invention, reference is made to the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings, wherein like reference numerals designate like or similar elements throughout the several figures of the drawings and wherein: 
           [0009]      FIG. 1  is a side, cross-sectional view of an exemplary wellbore containing a production assembly which incorporates five production nipples which incorporate sliding sleeve devices. 
           [0010]      FIG. 2  is a side view, partially in cross-section, illustrating an exemplary pressure controlled sliding sleeve device used within the production assembly of  FIG. 1 . 
           [0011]      FIG. 3  is a cut-away view of a portion of the housing for a sleeve controller used in the present invention. 
           [0012]      FIG. 4  is a side, cross-sectional view of an exemplary sleeve controller and associated components used within the present invention. 
           [0013]      FIGS. 5A-5C  are a schematic view of an exemplary control system for the multiple sliding sleeve valve devices shown in  FIG. 1  in a first configuration. 
           [0014]      FIGS. 6A-6C  are a schematic view of the exemplary control system of  FIGS. 5A-5C  now in a second configuration. 
           [0015]      FIGS. 7A-7C  are a schematic view of the exemplary control system of  FIGS. 5A-5C  and  6 A- 6 C now in a third configuration. 
           [0016]      FIG. 8  depicts alternative exemplary lug paths used within separate sleeve controllers. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0017]      FIG. 1  depicts an exemplary production wellbore  10  which has been drilled from the surface  12  downwardly through the earth  14 . The wellbore  10  passes through five separate hydrocarbon-bearing production formations  16 ,  18 ,  20 ,  22  and  24  which are separated from each other by strata  26  of substantially fluid-impermeable rock. The wellbore  10  has been lined with metallic casing  28  in a manner known in the art. 
         [0018]    A hydrocarbon production string  30  is disposed within the wellbore  10 . The production string  30  is made up of sections  32  of standard production tubing and production nipples  34 , which are used to receive production fluids from the surrounding annulus  36  and transmit them into the interior flowbore  38  of the production tubing string  30  via external openings  40 . Fluid flow through the nipples  34  is selectively controlled by an interior sliding sleeve, in a manner which will be described shortly. 
         [0019]    The production string  30  is disposed within the wellbore  10  until each of the production nipples  34  is generally aligned with one of the production formations  16 ,  18 ,  20 ,  22 ,  24 . Packers  42  are set within the annulus  36  between each of the formations  16 ,  18 ,  20 ,  22 ,  24  in order to isolate the production nipples  34 . Perforations  44  are disposed through the casing  28  and into each of the formations  16 ,  18 ,  20 ,  22 ,  24 . 
         [0020]    A hydraulic controller  46 , of a type known in the art, is located at the surface  12 . The controller  46  is a fluid pump which may be controlled manually or by means of a computer. Hydraulic control lines  48 ,  50  extend from the controller  46  into the wellbore  10 . The control lines  48 ,  50  are interconnected with a series of sleeve controllers  52   a ,  52   b ,  52   c ,  52   d  and  52   e  which are operably associated with each of the production nipples  34  for selective operation of the sliding sleeves contained therein. A hydraulic cycling line  54  also extends from a surface-based pump  56  to each of the production nipples  34 . 
         [0021]      FIG. 2  illustrates an exemplary production nipple  34  and sleeve controller  52  apart from the production string  30 . As can be seen, the production nipple  34  includes an interior chamber  58  which has a sliding sleeve member  60  moveably disposed within. The sleeve member  60  is shown in a first position in  FIG. 2 , wherein the sleeve member  60  does not block the fluid openings  40 . In this position, the production nipple  34  is “open” and allows production fluids within the annulus  36  to enter the chamber  58  for transport to the surface  12  via the string  30 . The sleeve member  60  can be moved to a second position, shown in phantom lines as  60   a  in  FIG. 2 . In the second position, the sleeve member  60  blocks the fluid openings  40 , and the production nipple  34  is considered to be “closed” such that production fluids in the annulus  36  cannot enter the chamber  58 . A cantilever arm  62  is secured to the sleeve  60  and extends into hydraulic cylinder  64 . An upper fluid conduit  66  extends from the upper end of the cylinder  64  to the sleeve controller  52  while a lower fluid conduit  68  extends from the lower end of the cylinder  64  to the sleeve controller  52 . The sleeve controller  52  is operably interconnected with each of the control lines  48 ,  50  and the cycling line  54 . 
         [0022]    The structure and operation of the sleeve controllers  52  is better understood with further reference to  FIGS. 3 and 4 . Each of the sleeve controllers  52  includes an outer, generally cylindrical housing  70  that defines an interior piston chamber  72 . The piston chamber  72  contains a compression spring  74  that is disposed upon inner flange  76 . A piston member  78  is moveably disposed within the chamber  72  and urged toward the upper end  80  of the chamber  72  by spring  74 . In the depicted embodiment, the piston member  78  includes a central shaft  82  which carries five radially-enlarged piston portions  84 ,  86 ,  88 ,  90  and  92  which are fixedly secured upon the shaft  82 . Each of these radially-enlarged portions carries an annular elastomeric seal  94  which forms a fluid seal against the surrounding housing  70 . 
         [0023]    One of the enlarged portions,  86 , carries a radially-outwardly extending lug member  96 . The lug member  96  resides within a lug path  98 , which is depicted as being inscribed in the interior wall of the housing  70 . Although  FIG. 4  depicts the lug path  98  as being actually inscribed on the interior wall of the housing, this is merely schematic. In actuality, the path  98  may be inscribed in a housing portion that is diametrically larger than the actual seal bore of the housing  70  or in an associated cylinder that is separate from the housing  70 .  FIG. 3  depicts an exemplary lug path in greater detail. During operation, the lug member  96  (shown in phantom lines in  FIG. 3 ) is restrained to move within the lug path  98 . 
         [0024]    Each of the sleeve controllers  52   a ,  52   b ,  52   c ,  52   d  and  52   e  has a unique lug path, which is best shown in  FIGS. 5A-5C .  FIGS. 5A-5C  depict the inscribed lug paths  98   a ,  98   b ,  98   c ,  98   d  and  98   e  for each of the sleeve controllers  52   a ,  52   b ,  52   c ,  52   d  and  52   e . For clarity, the lug paths are depicted in an “unrolled” fashion beside the corresponding sleeve controller  52   a ,  52   b ,  52   c ,  52   d  or  52   e . As is known in the art, a lug member  96  can be moved along each lug path by axial movement of the piston member  78  within the chamber  72 . The lug member  96  and lug path  98  thereby provide an indexing system for control of the axial position of the piston member  78  within the surrounding sleeve controller housing  70 , as will be described. Operation of complimentary lug members and lug paths is often referred to in the industry as a “J-slot” device. Such devices are described, for example, in U.S. Pat. No. 6,948,561 issued to Myron and entitled “Indexing Apparatus.” U.S. Pat. No. 6,948,561 is owned by the assignee of the present invention and is herein incorporated by reference in its entirety. 
         [0025]    In operation, the lug member  96  is moved along a lug path  98  as the piston member  78  is shifted upwardly and downwardly within the chamber  72 . The piston member  78  rotates within the chamber  72  to accommodate movement of the lug member from the path entrance  100  toward the path exit  102 . It is noted that, because the interior surface of the chamber  72  is curved to form a closed cylinder, the exit  102  will interconnect with the path entrance  100  to permit As can be seen in  FIGS. 5A-5C , the lug paths  98   a ,  98   b ,  98   c ,  98   d  and  98   e  include a series of upwardly and downwardly directed path legs. In the depicted embodiment, the downwardly directed legs  104  all are essentially the same length. There are also short upwardly directed legs  106  and longer upwardly directed legs  108 . When the lug member  96  is within the path  98 , it moves from an upwardly directed leg ( 106  or  108 ) to a downwardly directed leg  104  and back again, as indicated by the directional arrow path  110  in  FIG. 3 . It is noted that, as the lugs  96  enter the path entrance  100 , they travel to a first lug position, which is shown by the location of lug  96  in each of the lug paths  98   a ,  98   b ,  98   c ,  98   d  and  98   e  in  FIG. 5 . In order to shift the lug  96  into this first position, hydraulic fluid pressure within the cycling line  54  is reduced. This permits the spring  74  to urge the piston member  78  upwardly until the lug  96  enters the first available upwardly directed leg  106  or  108 . In the instance of the uppermost sleeve controller  52   a , the lug member  92  is moved upwardly into a longer upwardly directed leg  108 . In this position, the piston member  78  is positioned so that fluid flow path  110   a  from line  50  is in fluid communication with upper fluid conduit  66  and flow path  112   a  from line  48  is in fluid communication with lower fluid conduit  68 . It is noted that flow path  114   a  extends from the hydraulic control line  48  and into the chamber  72  below the spring  74  and piston member  78 . As a result, pressurization of the cycling line  54  will move the piston member downwardly within the chamber  72  while the compression spring  74  and pressurization of the control line  48  (via the flow path  114   a ) will move the piston upwardly within the chamber  72 . 
         [0026]      FIGS. 5A-5C  depict the five PCD sleeve devices  34 , here designated  34   a ,  34   b ,  34   c ,  34   d , and  34   e , in association with the control system provided by the sleeve controllers  52   a ,  52   b ,  52   c ,  52   d  and  52   e . Further, in  FIGS. 5A-5C , the sleeve controllers  52   a  . . .  52   e  are all in a first condition wherein the legs  96  of the respective sleeve controller pistons  78  are at their first lug position within their respective lug path  98   a ,  98   b ,  98   c ,  98   d  and  98   e . In this first position, some of the sleeve devices  34  can be operated to shift the sleeve  60  within while others are prevented from such operation. Because the control lines  48  and  50  are in fluid communication with the flow paths  66  and  68  via sleeve controller  52   a , the uppermost pressure controlled device  34   a  can be actuated by selective flow of fluid into and out of the device via lines  66 ,  68  to shift the sleeve member  60  therewithin. 
         [0027]    In contrast to the uppermost pressure controlled sleeve device  34   a , the second sleeve device  34   b  cannot be actuated to move its sleeve  60  between open and closed positions. The lug member  96  in lug path  98   b  is located in a short upwardly extending leg  106 . As a result, the piston member  78  in the sleeve controller  52  is located such that radially enlarged portion  86  of the piston member  78  is disposed between the fluid path  110   b  and the upper fluid conduit  66 , blocking fluid communication therebetween. The radially enlarged portion  90  of the piston member  78  is disposed between the fluid path  112   b  and the lower fluid conduit  68 , also blocking fluid communication between the common control line  48  and sleeve device  34   b.    
         [0028]    It can be seen from  FIGS. 5B and 5C  that the sleeve controllers  52   c ,  52   d  and  52   e  are in the same configuration as the sleeve controller  52   b . As a result, the sleeve devices  34   c ,  34   d  and  34   e  are also unable to be actuated by hydraulic fluid variation of the control lines  48 ,  50 . The sleeve devices  34   b ,  34   c ,  34   d  and  34   e  can be considered to be “locked out” from operation. Therefore, in the first control system position illustrated in  FIGS. 5A-5C , the uppermost PCD sleeve device  34   a  is the only sleeve device that can be operated via the control lines  48 ,  50 . 
         [0029]      FIGS. 4A ,  4 B and  4 C depict a second operational position for the control system wherein the lugs  96  of each sleeve controller  52   a ,  52   b ,  52   c ,  52   d  and  52   e  have been moved from the first control system position shown in  FIGS. 5A-5C  to a second position. The lugs  96  are moved to their second positions by pressurizing the common cycling line  54  and then depressurizing it a single time. Pressurizing the cycling line  54  will cause the lug member  96  of each sleeve controller  52  to move out of the first upwardly directed leg  106  or  108  and downwardly into the first downwardly-directed leg  102 . Upon depressurizing the common cycling line  54 , the springs  74  will urge the piston members  78  upwardly until the lugs  96  enter the second available upwardly-directed leg  106  or  108 . This pressurization and depressurization of the cycling line  54  can be used to sequentially step the sleeve controllers  52   a ,  52   b ,  52   c ,  52   d  and  52   e  through further operational positions. As can be seen in  FIGS. 6A-6C , the lugs  96  of each sleeve controller  52  are now located within a second upwardly-directed leg  106  or  108  within their respective lug paths  98   a ,  98   b ,  98   c ,  98   d  and  98   e . The lug  96  of the second sleeve controller  52   b  is disposed within an extended upwardly directed leg  108  while the lugs  96  of the remaining sleeve controllers  52   a ,  52   c ,  52   d  and  52   e  are all disposed in short upwardly directed legs  106 . As a result, the sleeve controller  52   b  is configured to permit the PCD sleeve device  34   b  to be actuated by the control lines  48 ,  50  while the remaining sleeve controllers  52   a ,  52   c ,  52   d  and  52   e  are configured to lock out operation of their respective PCD sleeve devices  34   a ,  34   c ,  34   d  and  34   e.    
         [0030]      FIGS. 7A-7C  depict the exemplary control system of the present invention in a third configuration. In this configuration, the lug members  96  of each sleeve controller  52   a ,  52   b ,  52   c ,  52   d  and  52   e  are located in a third upwardly-directed leg  106  or  108  in their respective lug path  98   a ,  98   b ,  98   c ,  98   d  or  98   e . In this configuration, only the lug member  96  of the third sleeve controller  52   c  is disposed within an extended upwardly-directed leg  108 . The lugs  96  of the remaining sleeve controllers  52   a ,  52   b ,  52   d  and  52   e  are located in shorter upwardly directed legs  106 . In this configuration, the PCD sleeve device  34   c  may be actuated while the remaining PCD sleeve devices  34   a ,  34   b ,  34   d  and  34   e  are locked out from actuation. 
         [0031]    This manner of selective isolation of individual PCD devices  34  for operation may be continued by pressurizing and depressurizing the common cycling line  54 . This will move the lugs  96  of the sleeve controllers  52   a ,  52   b ,  52   c ,  52   d  and  52   e  into subsequent upwardly extending legs  106  or  18  so that the remaining PCD sleeve devices  34   d  and  34   e  may be selectively isolated for actuation by the control lines  48 ,  50 . In the configuration wherein the lugs  96  are located in the fourth available upwardly directed legs  106 ,  108 , the PCD sleeve device  34   d  will be isolated for actuation by the control lines  48 ,  50 . In the configuration wherein the lugs  96  are located in the fifth available upwardly-directed legs  106  or  108 , the PCD sleeve device  34   e  will be isolated for actuation by the control lines  48 ,  50 . 
         [0032]      FIG. 8  illustrates an alternative set of lug paths  98   a ′,  98   b ′  98   c ′,  98   d ′ and  98   e ′ having a “common open” position and a “common closed” position. The lug position  96 ′ is shown wherein each of the lugs  96 ′ are disposed within an extended length upwardly-directed leg  108 . This “common open” configuration permits all of the PCD sleeve devices  34   a ,  34   b ,  34   c ,  34   d  and  34   e  to be simultaneously actuated via the common control lines  48 ,  50 . A “common closed” lug position  96 ″ is also shown wherein all of the corresponding PCD sleeve devices  34   a ,  34   b ,  34   c ,  34   d  and  34   e  are locked out from actuation by variations in fluid pressure within the control lines  48 ,  50 . 
         [0033]    It can be seen that the sleeve controllers  52   a ,  52   b ,  52   c ,  52   d  and  52   e  and cycling line  54  collectively provide an operating system for selectively controlling the plurality of PCD devices  34   a ,  34   b ,  34   c ,  34   d , and  34   e  using common hydraulic control lines  48 ,  50 . In operation, each of the PCD sleeve devices  34   a ,  34   b ,  34   c ,  34   d , and  34   e  may be selectively operated by cycling the sleeve controllers  52   a ,  52   b ,  52   c ,  52   d  and  52   e  to a position wherein one of the sleeve devices  34  can be isolated for operation while the remaining sleeve devices  34  are locked out from operation by the control lines  48 ,  50 . In addition, the control system of the present invention may be used to cause all of the PCD sleeve devices  34  to be operated simultaneously by moving the sleeve controllers  52  into a “common open” configuration. Also, all of the PCD sleeve devices  34  may be locked out from actuation by moving the sleeve controllers  52  into a “common closed” configuration. 
         [0034]    Those of skill in the art will likewise recognize that the lug paths  98  for the sleeve controllers  52  may be customized to have positions wherein more than one but fewer than all of the PCD sleeve devices  34  may be actuated by the common control lines  48 ,  50 . For example, in a particular setting, the lug paths  98   a  and  98   b  would have extended length upwardly-directed legs  108  while the remaining lug paths  98   c ,  98   d  and  98   e  would have short upwardly directed legs  106 . When the lug members  96  are located in these positions, PCD devices  34   a ,  34   b  could be operated via the control lines  48 ,  50  while the remaining PCD devices  34   c ,  34   d  and  34   e  are locked out from operation. 
         [0035]    The described embodiment depicts five PCD sleeve devices  34 . However, there can be more or fewer than five PCD devices, depending upon the needs of the particular wellbore. In addition, while the particular PCD devices that are described for use with the described control system are sliding sleeve devices, they may also be other hydraulically controlled devices, such as safety valves or chemical injection valves. 
         [0036]    Those of skill in the art will recognize that numerous modifications and changes may be made to the exemplary designs and embodiments described herein and that the invention is limited only by the claims that follow and any equivalents thereof.

Summary:
Systems and methods for selectively operating multiple hydraulic pressure controlled devices (PCDs) within a borehole using a common inflow and outflow line and a common cycling line. A control system is used wherein each of the PCDs is operationally associated with a separate sleeve controller. The sleeve controller for each PCD controls whether the individual PCD can be actuated by hydraulic pressure variations in the common inflow and outflow lines.