Abstract:
A wellhead assembly including a tubing hanger adapted to be connected to a tubing string and landed in a wellhead, and defining a tubing annulus between the tubing string and casing in a well. The wellhead assembly also includes a tubing annulus upper access bore extending downward from an upper end of the tubing hanger, and a tubing annulus lower access bore extending upward from a lower end of the tubing hanger and misaligned with the upper access bore, the lower access bore adapted to communicated with the tubing annulus. A communication cavity connects the upper and lower access bores within the tubing hanger. A remotely actuated valve is in the communication cavity for selectively opening and closing communication between the lower access bore and the upper access bore.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    This technology relates to oil and gas wells. In particular, this technology relates to valves to control the flow of annular fluid from the annulus of a well through a tubing hanger. 
         [0003]    2. Brief Description of Related Art 
         [0004]    Typical drilling operations include a high pressure wellhead having a tubing hanger mounted therein. The purpose of the tubing hanger is to support tubing extending into the well. Typical tubing hangers include a production bore which extends vertically through the hanger. After the tubing hanger is set access to the annulus of the well is impeded by the body of the tubing hanger, as well as by other wellhead equipment. Despite the difficulty of accessing the annulus, however, there remains a need after the tubing hanger is set to access the annulus for such things as testing and monitoring of annular fluid. One way to access such annular fluid is by providing a port through the tubing hanger from the top of the tubing hanger to the annulus. Such a port should have a valve for controlling access to the annular fluid and limiting access to appropriate times in the production and completion process. 
       SUMMARY OF THE INVENTION 
       [0005]    Disclosed herein is a wellhead assembly that may include a wellhead housing attached to a wellhead, and a production tree having a production bore and attached to the top of the wellhead housing. A tubing hanger is adapted to be connected to a tubing string and landed in the wellhead housing, the tubing hanger having a production bore and defining a tubing annulus between the tubing string and casing in a well. The assembly may further include an isolation sleeve positioned between the tubing hanger and the production tree, the isolation sleeve having a bore that provides fluid communication between the production bore of the tubing hanger and the production bore of the production tree. 
         [0006]    A tubing annulus upper access bore extends downward from an upper end of the tubing hanger, and a tubing annulus lower access bore extends upward from a lower end of the tubing hanger, and is misaligned with the upper access bore. The lower access bore is adapted to communicate with the tubing annulus. In some embodiments, the upper and lower tubing annulus access bores may be parallel to each other and circumferentially spaced apart. 
         [0007]    A communication cavity connects the upper and lower access bores within the tubing hanger. In some embodiments, the communication cavity may extend axially parallel to the access bores and circumferentially spaced between the access bores. A remotely actuated valve is positioned in the communication cavity for selectively opening and closing communication between the lower access bore and the upper access bore. In certain embodiments, the valve may include a perforated valve stem having an axially extending flow chamber therein. The flow chamber defines a bottom end, a top end, and cylindrical sidewalls with perforations extending therethrough. 
         [0008]    A first lateral port extends from the lower access bore to the flow chamber, and a second lateral port extends from the upper access bore to the flow chamber, so that when the valve is in an open position, the flow chamber is in communication with the first and second lateral ports, and when the valve is in a closed position, communication between the flow chamber and at least one of the lateral ports is blocked. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    The present technology will be better understood on reading the following detailed description of nonlimiting embodiments thereof, and on examining the accompanying drawings, in which: 
           [0010]      FIG. 1  is a side cross-sectional view of a wellhead assembly according to an embodiment of the present technology; 
           [0011]      FIG. 2A  is an enlarged side cross-sectional view of a perforated stem according to an embodiment of the technology in a closed position; 
           [0012]      FIG. 2B  is an enlarged side cross-sectional view of a perforated stem according to an embodiment of the technology in an open position; 
           [0013]      FIG. 3  is an enlarged side cross-sectional view of the opening in the perforated stem of  FIG. 2B ; 
           [0014]      FIG. 4  is a top view of certain components of the wellhead assembly of  FIG. 1 ; 
           [0015]      FIG. 5A  is a side cross-sectional view of a tree override assembly according to an embodiment of the present technology; 
           [0016]      FIG. 5B  is an enlarged side cross-sectional view of the top of a perforated stem and override assembly, when the perforated stem is in the open position; 
           [0017]      FIG. 5C  is an enlarged side cross-sectional view of the top of a perforated stem and override assembly, when the perforated stem is in the closed position; 
           [0018]      FIG. 6  is an enlarged side cross-sectional view of a running tool override assembly according to an embodiment of the present technology; 
           [0019]      FIG. 7A  is a side cross-sectional view of an alternate embodiment of the present technology, including a biasing mechanism and where the perforated stem is in a closed position; 
           [0020]      FIG. 7B  is a side cross-sectional view of the embodiment of  FIG. 7A , where the perforated stem is in an open position. 
           [0021]      FIG. 8  is a side cross-sectional view of an embodiment of the present technology having two perforated stems in a parallel configuration; 
           [0022]      FIG. 9  is a side cross-sectional view of an alternate embodiment having two perforated stems in a parallel configuration; and 
           [0023]      FIG. 10  is a side cross-sectional view of an embodiment of the present technology having two perforated stems arranged in series. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0024]    The foregoing aspects, features, and advantages of the present technology will be further appreciated when considered with reference to the following description of preferred embodiments and accompanying drawings, wherein like reference numerals represent like elements. In describing the preferred embodiments of the technology illustrated in the appended drawings, specific terminology will be used for the sake of clarity. However, the technology is not intended to be limited to the specific terms used, and it is to be understood that each specific term includes equivalents that operate in a similar manner to accomplish a similar purpose. 
         [0025]      FIG. 1  is a depiction of a wellhead assembly  10  according to an embodiment of the present technology. The wellhead assembly may include such features as a wellhead housing  12  mounted within a wellhead  14 . A casing hanger  16  may be positioned within the wellhead housing  12  to support casing, and a tubing hanger  18  may be inserted above the casing hanger  16 . In some embodiments, the tubing hanger  18  may be a five inch nominal concentric vertical tubing hanger, although other sizes are possible (e.g., six inch, seven inch, etc.). The tubing hanger  18  may typically support tubing  20  extending into the well, and may rest on, and be at least partially supported by the casing hanger  16 . The tubing hanger  18  includes a production bore  22  which provides access through the tubing hanger  18  to the tubing  20 . The area around the tubing  20 , and between the tubing hanger  18  and the casing, is an annulus  24  of the well. 
         [0026]    During well operations, it may be desirable for an operator to access fluid in the annulus  24  to analyze conditions in the annulus  24 , such as temperature, composition of annular fluid, etc. Accordingly, annulus access valve assembly  26  is provided in the wellhead assembly  10  to provide access between the annulus  24  and the top of the tubing hanger  18 , thereby allowing monitoring of annular fluid through a tubing hanger running tool (shown, e.g., in  FIG. 6 ) or production tree (shown, e.g., in  FIG. 5A ) in communication with the top of the tubing hanger  18 . As used herein, the term valve has an expansive definition, and refers to any sealing mechanism or device that may be used to control the flow of annular fluid through the tubing hanger. The annulus access valve assembly  26  may be configured to have a working pressure rating of up to 10,000 pounds per square inch (psi) or more, and may typically allow access to the annulus with an operating pressure of 3,000 to 5,000 psi. Once annular fluid is brought from the annulus  24  to the top of the well, the operator can easily access the annular fluid for analysis and testing. 
         [0027]    Referring now to  FIGS. 2A and 2B , there is illustrated an enlarged view of the annular access valve assembly  26  shown in  FIG. 1 . The annular access valve assembly  26  includes a valve body  28  having a valve chamber  30 . In the embodiments shown, the valve body  28  is positioned in a vertical configuration in the tubing hanger  18 . In  FIG. 2A , the valve body  28  is shown in a closed position, and in  FIG. 2B , the valve body  28  is shown in an open position. A first side of the valve body  28  is fluidly engaged with a lower access port  32 , which is in turn in fluid communication with a lower annular access bore  33 . A second side of the valve body  28  is fluidly engaged with an upper access port  34 , which is in turn in fluid communication with an upper annular access bore  35 . The upper annulus access bore opens to the top of the tubing hanger  18 . In some embodiments, the upper annular access bore  35  can have a profile  31 , which may be threaded or otherwise, to accept a backup plug (not shown). Such a backup plug may be useful for plugging the upper annular access bore  35  if desired, such as, for example, when the production tree is removed from the tubing hanger  18  subsea. 
         [0028]    In  FIGS. 2A and 2B , the flow path of annular fluid is shown by arrows P. When the valve body  28  is in a closed position, as shown in  FIG. 2A , the valve chamber  30  does not align with the lower access port  32 , and fluid is prevented from flowing from the lower access port  32  into the valve chamber  30 . Thus, fluid communication between the lower access port  32  and the upper access port  34  is prevented. 
         [0029]    Conversely, when the valve body  28  is in an open position, as shown in  FIG. 2B , the valve chamber  30  aligns with the lower access port  32 . Thus, fluid is free to flow from the lower access port  32  into the valve chamber  30 . The valve chamber  30  is also open to the upper access port  34 , as described in greater detail below, so that when the valve body  28  is open, fluid may freely flow from the lower access port  32 , through the valve chamber  30 , and into the upper access port  34 , thereby providing fluid access from the lower access port  32  to the upper access port  34  of the tubing hanger  18 . 
         [0030]    Also shown in  FIGS. 2A and 2B  is a lower hydraulic control line  38 , which may be accessed through the production tree or running tool. The lower hydraulic control line  38  may provide hydraulic fluid to an area  42  below the valve chamber  30 , and allow for hydraulic control of the position of the valve body  28  from below. For example, when the valve body  28  is in a closed position, as shown in  FIG. 2A , hydraulic fluid can be provided to area  42 , thereby providing a hydraulic force F U  on the valve body that acts in an upward direction. Such a hydraulic force F U  pushes the valve body  28  upward from the closed to the open position. Conversely, when the valve body  28  is in the open position, as shown, for example, in  FIG. 2B , hydraulic fluid may be provided to area  40  via fluid port  36 , thereby providing an opposite hydraulic force F D  that pushes the valve body  28  downward from the open position to the closed position. Accordingly, the position of the valve body  28  can be controlled by means of the upper and lower control lines  36  and  38 . Furthermore, standard slim couplers, as used on various known tubing hanger systems, may be used to control hydraulic valves connected to the hydraulic lines  36  and  38 . 
         [0031]    Referring now to  FIG. 3 , there is shown an enlarged view of the valve chamber  30  and other components. As shown, valve chamber  30  is a void contained within the valve body  28 . The valve chamber  30  is enclosed by sidewalls  45  which form cylindrical sealing surfaces, and which are integral to, and form a portion of, the valve body  28 . The sidewalls  45  have upper openings  47  and lower openings  49  that provide access between the valve chamber  30  and the outside of the valve body  28 . The upper and lower openings  47 ,  49  are located at an upper end  30 A and a lower end  30 B of the valve chamber  30  respectively. 
         [0032]      FIG. 3 , the valve body  28  is in the open configuration. At the interface between the lower access port  32  and the valve body  28 , there are seals that prevent annular fluid from leaking past the valve body  28  and the tubing hanger  18 . These seals include upper and lower metal seals  48 ,  50 , whose purpose is to form a dynamic seal against the surface of the valve body  28 , even as the valve body moves upward and downward between open and closed positions. Each of upper arid lower metal seals  48 ,  50  is substantially cylindrical and surrounds the valve body  28 . Each of the upper and lower metal seals  48 ,  50  also has a substantially U-shaped cross-section with a first metal seal leg  52 ,  54  that extends substantially adjacent to the valve body  28 , and a second metal seal leg  56 ,  58  that extends substantially adjacent to the tubing hanger  18 . Also shown is a stem seal ring  59  tor sealing the interface between the valve body  28  and the tubing hanger  18  at the bottom end of the valve body  30 . 
         [0033]    In practice, the area  60 ,  62  between the first and second metal seal legs of each seal  48 ,  50  fills with annular fluid, and the annular fluid exerts pressure forces outwardly from the areas  60 ,  62 , including against the first  52 ,  54  and second  56 ,  58  metal seal legs. The first metal seal leg  52 ,  54  of each seal is dynamic, so that as pressure from the annular fluid acts on the first metal seal legs  52 ,  54 , they are elastically deformed, and pushed into sealed engagement with the valve body  28  so that no fluid can pass between the metal seals  48 ,  50  and the valve body  28 . In some embodiments, the first metal seal legs  52 ,  54  may be resilient and biased against the valve body  28  even before annular fluid pressure is applied. The second metal seal legs  56 ,  58  may be static, and may have thicker cross-sections than the first metal seal legs  52 ,  54 . The second metal seal legs  56 ,  58  are configured to seal against the tubing hanger  18  so that no fluid can pass between the upper and lower metal seals  48 ,  50  and the tubing hanger  18 . In alternative embodiments (not shown), the metal seals  48 ,  50  may each be symmetrical, with both the first  52 ,  54  and second  56 ,  58  metal seal legs being dynamic and elastically deformable. 
         [0034]    In the embodiments shown, the inside surface of the first metal legs  52 ,  54  of the upper and lower metal seals  48 ,  50  is substantially straight and adjacent to the surface of the valve body  28  along the entire height of the seal  48 ,  50 . Such an arrangement is advantageous because it allows transmission of pressure forces from the first metal legs  52 ,  54  and into the valve body  28  over the entire height of the seal  48 ,  50 . This design is in contrast to other known seal designs, many of which include a sealing surface proximate the stem of a valve body that tapers away from the valve body along part of the height of the seal. Such tapered designs can be problematic because they can lead to high stresses in the first metal legs  52 ,  54 , which can in turn lead to failure of the seals. In the design of the present technology, such stresses are eliminated, thereby increasing the reliability of the upper and lower metal seats  48 ,  50 , as well as increasing the amount of pressure that the seals  48   50  can withstand. In addition, in some embodiments, the sealing surfaces of the upper and lower metal seals  48 ,  50  may be coated with a seal coating. Additional elastomer seals  64  are provided as backup seals to the upper and lower metal seals  48 ,  50 , and also to seal the interfaces between the stem seal ring  59 , the valve body  28 , and the tubing hanger  18 . These elastomeric seals can also serve to seal off area  40  above the seals. 
         [0035]    A seal spacer  66  having openings  68 , is provided between the upper and lower metal seats  48 ,  50 . Upper and lower ends  70 ,  72  of the seal spacer  66  extend into the area  60 ,  62  between the first and second metal seal legs of each seal  48 ,  50  and contact the seals  48 ,  50 . The seal spacer  66  is not an energizing member, but rather serves to maintain the relative axial positions of the upper and lower metal seals  48 ,  50  relative to one another, thereby preventing the seals  48 ,  50  from moving toward one another and blocking the annular access port  32 . The openings  68  in the seal spacer  66  allows the annular fluid to pass through the seal spacer  66  and into the valve chamber  30  through the upper openings  47  in the sidewalls  45  when the valve body  28  is in the open position, as shown in  FIG. 3 . In addition, the surface of the valve body  28  may be provided with a step  73 . This step  73  serves to prolong the life, and reduce or eliminate damage to, the lower metal seal  50  and the back up seals  64  by reducing contact between the sidewalk  45  of the valve body  28  and the lower metal seal  50  and back up seals  64  as the valve body  28  moves from the open to the closed position. 
         [0036]    Referring to  FIG. 4 , there is depicted a top view of the wellhead assembly  10  according to an embodiment of the present technology, without the high pressure wellhead  12  or the connector  14  (shown in  FIG. 1 ). In  FIG. 4 , the tubing hanger  18  is shown, along with annulus access assembly  26 , the production bore  22 , the upper annular access bore  35 , the lower hydraulic control line coupler  37 , and the upper hydraulic control line coupler  39 . Also shown are additional components, such as connectors  74  for down hole pressure and temperature (DHPT) sensors, a tubing hanger land confirm sensor  76 , a tubing hanger lock confirm sensor  78 , as well as extra hydraulic couplers  80  for attachment to additional components that may be added to the assembly in the future. 
         [0037]      FIG. 5A  depicts an alternate embodiment of the present technology that provides a different way to move the valve body  28  between an open and a closed position. In particular.  FIG. 5A  shows a tree override unit  82  that may be attached to a production tree  84 , and positioned above the annular access assembly  26  when the tree  84  is placed over the wellhead housing  12 . An override extension  85  is shown positioned between the tree  84  and the tubing hanger  18 . Typically, such an override would be activated if the primary hydraulic functions fail, although this is not necessary. 
         [0038]    As best shown in  FIGS. 5B and 5C , the tree override unit  82  may include an override extension  85  that includes an override piston  86 , a seal housing  88 , a dog ring  90 , and an override sleeve  92 . The top of the valve body  28  may include an override head  94  having inward protrusions  96  (best shown in  FIG. 6 ). When the tree  84  is positioned above the high pressure housing  12 , the override extension  85  is substantially axially aligned with the valve body  28 . The override piston  86  and seal housing  88  seal against the override extension  85  so that fluid cannot pass between any of the override piston  86 , the seal housing  88 , or the override extension  85 . To ensure a sealed interface between these components, elastomeric seals  64  can be provided between the override piston  86  and the seal housing  88 , between the override extension  85  and the override piston  86 , and between the override extension  85  and the seal housing  88 , as shown. 
         [0039]    In practice, hydraulic fluid can be introduced to an area  98  above the override piston  86  by means of a hydraulic line  100  or the area  110  below the override piston  86  by means of a hydraulic line  108 . lire hydraulic fluid drive the override piston  86  downwardly as the fluid enters the area  98 . The dog ring  90 , which is attached to the end of the override piston  86 , has outward facing dog edges  102  that are configured to engage the inward protrusion  96  of the override head  94  at the top of the valve body  28 . The override sleeve  92  surrounds the override head  94  on an outside surface thereof. Once attached, the override head  94  and valve body  28  are coupled to the override piston  86  via the dog ring  90  and the override sleeve  92 . As hydraulic fluid is pushed into area  98  through the hydraulic line  100 , the override piston  86 , and consequently the override head  94  and valve body  28 , are pushed downward, as shown in  FIG. 5C . This downward movement of the valve body  28  causes the valve body  28  to move into a closed position, as described above. Conversely, the introduction of hydraulic fluid to area  110  causes the override piston  86 , override head  94 , and valve body  28  to rise, as shown in  FIG. 5B , thereby moving the valve body  28  into an open position. Though not shown, the valve body may be attached to both the tree override unit  82  and the upper and lower hydraulic lines  36  and  38  simultaneously. Thus, an operator may have multiple different mechanisms for controlling the annulus access valve assembly  26 . 
         [0040]    Referring to  FIG. 6 , there is shown an annulus access valve assembly  26  in a tubing hanger  18 , and having a tubing hanger running tool  104  attached thereto. The tubing hanger running tool  104  includes a running tool override unit  106  substantially similar to the tree override unit  82  shown in  FIG. 5A . The running tool override unit  106  is positioned above the annular access assembly  26  when the running tool  104  is placed over the tubing hanger  18 . 
         [0041]    Like the tree override unit  82 , the running tool override unit  106  may include an override piston  86 , a seal housing  88 , a dog ring  90 , and an override sleeve  92 . The top of the valve body  28  may include an override head  94  having inward protrusions  96 . When the running tool  104  is positioned above the tubing hanger  18 , the override piston  86  is substantially axially aligned with the valve body  28 . The override piston  86  and seal housing  88  seal against the running tool  104  so that fluid cannot pass between any of the override piston  86 , the seal housing  88 , or the running tool  104 . To ensure a sealed interlace between these components, elastomeric seals  64  can be provided between the override piston  86  and the seal housing  88 , between the running tool  104  and the override piston  86 , and between the running tool  104  and the seal housing  88 , as shown. 
         [0042]    In practice, hydraulic fluid can be introduced above the override piston  86  by means of a hydraulic line  100  or the area  110  below the override piston  86  by means of a hydraulic line  108 . The hydraulic fluid can drive the override piston  86  downwardly or upward as the amount of fluid introduced above or below the override piston  86  is varied. The dog ring  90 , which is attached to the end of the override piston  86 , has outward facing dog edges  102  that are configured to engage the inward protrusion  96  of the override head  94  attached to the valve body  28 . The override sleeve  92  surrounds the override head  94  on an outside surface thereof. Once attached, the override head  94  and valve body  28  are coupled to the override piston  86  via the dog ring  90  and the override sleeve  92 . As hydraulic fluid is introduced above the override piston  86  through the hydraulic line  100 , the override piston  86 , and consequently the override head  94  and valve body  28 , are pushed downward. This downward movement of the valve body  28  causes the valve body  28  to move into a closed position, as described above. Conversely, the introduction of hydraulic fluid to area  110  causes the override piston  86 , override head  94 , and valve body  28  to raise, thereby moving the valve body  28  into an open position. As in the embodiment of  FIGS. 5A-5C , the valve body may be attached to the tool override unit  106 , the upper hydraulic line  36 , and the lower hydraulic  38 . Thus, an operator may have multiple different mechanisms for controlling the annulus access valve assembly  26 . 
         [0043]      FIGS. 7A and 7B  show an alternate embodiment of the annular access valve assembly  126 . The annular access valve assembly  126  includes a valve body  128  having a valve chamber  130 . As in the embodiment of  FIGS. 1-3 , the valve body  128  has a valve chamber  130 . In  FIG. 7A , the valve body  128  is shown in a closed position, and in  FIG. 7B , the valve body  128  is shown in an open position. A first side of the valve body  128  is fluidly engaged with a lower access port  132 , which is in turn in fluid communication with a lower annular access bore  133 . A second side of the valve body  128  is fluidly engaged with an upper access port  134 , which is in turn in fluid communication with an upper annular access bore  135 . As discussed above with regard to the embodiment of  FIGS. 2A-2B , the upper annular access bore  135  may have a profile  131  to accept a backup plug (not shown), thereby allowing for closing of the upper annular access bore  135  if desired. 
         [0044]      FIGS. 7A and 7B , the flow path of annular fluid is shown by arrows P. When the valve body  128  is in a closed position, as shown in  FIG. 7A , the valve chamber  130  does not align with the lower access port  132 , and fluid is presented from flowing from the lower access port  132  into the valve chamber  130 . Thus, fluid communication between the lower access port  132  and the upper access port  134  is prevented. 
         [0045]    Conversely, when the valve body  128  is in an open position, as shown in  FIG. 7B , the valve chamber  130  aligns with the lower access port  132 . Thus, fluid is free to flow from the lower access port  132  into the valve chamber  130 . The valve chamber  130  is also open to the upper access port  134 , as described in greater detail below, so that when the valve body  128  is open, fluid may freely flow from the lower access port  132 , through the valve chamber  130 , and into the upper access port  134 , thereby providing fluid access from the lower access port  132  to the upper access port  134  of the tubing hanger  18 . 
         [0046]    Also shown in  FIGS. 7A and 7B  are an upper hydraulic control line  136  and a lower hydraulic control line  138 , which, may be accessed through the production tree or running tool. Upper hydraulic control line  136  provides hydraulic fluid to an area  140  above the valve chamber  130 , and allows for hydraulic control of the position of the valve body  128  from above. For example, when the valve body  128  is in an open position, as shown in  FIG. 7B , hydraulic fluid can be provided to area  140 , thereby providing a hydraulic force F D  on the valve body that acts in a downward direction. Such a hydraulic force F D  pushes the valve body  128  downward from the open position to the closed position. Conversely, lower hydraulic control line  138  may provide hydraulic fluid to an area  142  below the valve chamber  130 , and allow for hydraulic control of the position of the valve body  128  from below. For example, when the valve body  128  is in a closed position, as shown in  FIG. 7A , hydraulic fluid can be provided to area  142 , thereby providing a hydraulic force F U  on the valve body that acts in an upward direction. Such a hydraulic force F U  pushes the valve body  128  upward from the closed to the open position. Accordingly, the position of the valve body  128  can be controlled by means of the upper and lower control lines  136 ,  138 , operated either individually or in combination. Alternatively, in some embodiments, lines  136 ,  138  may be vent lines which allow air to enter and exit the areas  140 ,  142  above and below the valve chamber  130  as the valve body  128  moves between open and closed positions. Furthermore, standard slim couplers, as used on various known tubing hanger systems, may be used to control hydraulic valves connected to the hydraulic lines  136 ,  138 . 
         [0047]    Also shown in  FIGS. 7A and 7B  is a biased mechanism  144  which, in the particular embodiment shown, is a spring. The biased mechanism  144  is housed above the valve chamber  130  in a recess  146 , and is arranged to provide a constant force on the valve body  128  in a downward direction. The biased mechanism  144  is useful to push the valve body  128  into a closed position in case a malfunction occurs in the hydraulic control lines  136 ,  138 . The constant downward force on the valve body  128  provided by the biased mechanism  144  provides a safeguard to ensure that in the absence of opposing hydraulic control forces, the valve body  128  remains in the closed position. Although the biased mechanism  144  is shown as a spring, any other type of biased mechanism could be used. 
         [0048]    As shown in  FIGS. 7A and 7B , line  138  may run vertically down through the tubing hanger  18 , and then horizontally across to communicate with area  142 . The bottom of area  142  acts as the stop position for the valve body  128  as it moves into the closed position. Line  136  may be drilled at an angle from the top of the tubing hanger  18  to the area  140 . 
         [0049]      FIGS. 8-10  show alternative embodiments of the present technology wherein more than one annular access assembly  226  is included in a single tubing hanger  218  having an upper annular access bore  235 . As discussed above with regard to the embodiment of  FIGS. 2A-2B , the upper annular access bore  235  may have a profile  231  to accept a backup plug (not shown), thereby allowing for closing of the upper annular access bore  235  if desired. In  FIG. 8 , two annular access assemblies  226   a,    226   b  are shown arranged in a parallel configuration. In this embodiment, each annulus access assembly  226   a ,  226   b  has a valve body  228   a ,  228   b  with a value chamber  230   a ,  230   b . In  FIG. 8 , the valve bodies  228   a ,  228   b  are shown in a closed position. A first side of each valve body  228   a,    228   b  is fluidly engaged with a separate lower access port  232   a,    232   b.  A second side of each valve body  228   a,    228   b  is fluidly engaged with an upper access port  234 . The use of two separate lower access ports  232   a,    232   b  allows access to two different places in the annulus. 
         [0050]    As described above with reference to a single annulus access assembly  26 , when the valve bodies  228   a,    228   b  are in closed positions, the valve chambers  230   a,    230   b  do not align with the lower access ports  232   a,    232   b,  and fluid is prevented from flowing from the lower access ports  232   a,    232   b  into the valve chambers  230   a,    230   b.  Conversely, when the valve bodies  228   a ,  228   b  are in an open position (as shown in the analogous example of  FIG. 2B ), the valve chambers  230   a ,  230   b  align with the lower access ports  232   a,    232   b.  Thus, fluid is free to flow from the lower access ports  232   a,    232   b  into the valve chambers  230   a,    230   b.  The valve chambers  230   a ,  230   b  are also open to the upper access port  234  so that when the valve bodies  228   a,    228   b  are open, fluid may freely flow from the lower access ports  232   a,    232   b,  through the valve chambers  230   a,    230   b,  and into the upper access port  234 . 
         [0051]    Also shown in  FIG. 8  is a lower hydraulic control line  238 . The lower hydraulic control line  238  provides hydraulic fluid to the valve bodies  228   a,    228   b  below the valve chambers  230   a ,  230   b,  and allows for hydraulic control of the position of the valve bodies  228   a,    228   b  from below. Accordingly, the position of the valve bodies  228   a,    228   b  can be controlled by means of the lower control line  238 . Lines  236 ,  238  may alternatively be vent lines. Although  FIG. 8  shows a single lower hydraulic control line  238  in hydraulic communication with both valve bodies  228   a,    228   b,  it is to be understood that the technology alternatively contemplates two separate lower hydraulic control lines, with one line running to each valve body individually. 
         [0052]    Other components, such as upper and lower metals seals, elastomeric seals, a stem seal ring, a seal spacer, and an override head may be included with each of the parallel annulus access valve assemblies  226   a ,  226   b,  and have the same structure and functions as related counterparts discussed above in relation to annulus access valve assembly  26 . 
         [0053]    The embodiment shown in  FIG. 9  also includes two annular access assemblies  326   a,    326   b  arranged in a parallel configuration and including valve bodies  328   a,    328   b  and valve chambers  330   a ,  330   b.  The annular access assemblies  326   a,    326   b  also include features discussed above, such as upper and lower metals seals, elastomeric seals, a stem seal, ring, a seal spacer, and an override head, and have the same structure and functions as related counterparts discussed above in relation to annulus access valve assembly  26 . One difference between the embodiment of  FIG. 9 , however, and that shown in  FIG. 8 , is that both annular access assemblies  326   a,    326   b  of  FIG. 9  are attached to a single lower access port  332 . In the embodiment shown, both valve bodies  328   a,    328   b  are in a closed position. 
         [0054]    Also shown in  FIG. 9  is a lower hydraulic control line  338 . The lower hydraulic control line  338  provides hydraulic fluid to the valve bodies  328   a,    328   b  below the valve chambers  330   a ,  330   b,  and allows for hydraulic control of the position of the valve bodies  328   a,    328   b  below the valve chambers  330   a,    330   b  from below. The lower hydraulic control lines can be singular or plural. 
         [0055]    In  FIG. 10  there is shown yet another pair of annulus access assemblies  426   a,    426   b.  In  FIG. 10 , however, the annulus access assemblies  426   a,    426   b  are provided in series. Thus, in order for annular fluid to pass from the lower access port  432  to the upper access port  434 , both valve bodies  428   a,    428   b  must be positioned in the open position. If either valve body  428   a,    428   b  is in the closed position, fluid will not be able to pass through the closed valve body. Other than the configuration of the annulus access assemblies  426   a,    426   b  in series, the existence and arrangement the components associated with each annulus access assembly  426   a,    426   b  is the same as that shown and described above. 
         [0056]    Embodiments of the present technology that include more than one annular access assembly may be advantageous because they provide redundancy to the system. For example, in the case of the parallel annulus access assemblies  226   a,    226   b  of  FIG. 8 , the annulus can be accessed via more than one annulus access port, thereby providing multiple samples of the annular fluid to add a degree of confidence that the fluid being analyzed is representative of the fluid as a whole in the annulus. In the case of the parallel annular access assemblies  326   a,    326   b  in  FIG. 9 , the provision of two assemblies means that if one assembly becomes inoperable and is stuck in the closed position, flow from the lower access port  332  can still be controlled using the remaining assembly. Finally, in the case of the series of annulus access assemblies shown in  FIG. 10 , the failure of one valve body to close does not mean that access to the annulus must remain open because the other assembly can still be closed. Although three possible configurations of annulus access assemblies are shown in  FIGS. 8-10 , these are only exemplary of many possible embodiments and should not be interpreted as limiting the scope of arrangements contemplated by the present technology. 
         [0057]    While the technology has been shown or described in only some of its forms, it should be apparent to those skilled in the art that it is not so limited, but is susceptible to various changes without departing from the scope of the invention. Furthermore, it is to be understood that the above disclosed embodiments are merely illustrative of the principles and applications of the present invention. Accordingly, numerous modifications may be made to the illustrative embodiments and other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.