Abstract:
A landing string for landing a tubing hanger in a tubing spool has flow lines for actuating annulus access valves. A tubing string depends from the tubing hanger, and projects into a wellbore lined with casing when the tubing hanger is landed. Piping outside of the tubing spool connects to a bore formed through the tubing spool to provide access to an annulus between the tubing string and casing. The annulus access valve is in the flow line to control flow to the annulus. The valve is driven by an actuator that is operated by fluid in a flow line ported through the landing string, and in communication with the tubing spool when the tubing hanger is landed.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The present disclosure relates in general to a subsea wellhead assembly, and in particular to controlling an annulus access valve via a landing string. 
         [0003]    2. Description of Prior Art 
         [0004]    A wellhead assembly is typically mounted over a hydrocarbon producing well for handling fluids produced from the well. Wells are generally lined with casing, where produced fluid flows from the formation adjacent the well, through perforations in the casing, and into the well. The produced fluids flow from the well to the wellhead through a tubing string that is supported by a tubing hanger in the wellhead assembly. The tubing hanger lands in a wellhead member, which is usually one of a wellhead housing, a tubing spool mounted on top of a wellhead housing, or a production tree. Various workover and completion operations require fluid circulation down the tubing and back up a tubing annulus surrounding the tubing, or vice-versa. Wellhead assemblies typically include flow passages, fittings, and valves that allow for selective access to the tubing annulus and provide a return path for circulation of the fluid pumped into the well. 
         [0005]    One type of flow passage in a wellhead assembly is a tubing annulus passage extending through the body of the tubing hanger which communicates with the tubing annulus. In an offshore well completion, the operator may install a plug in the tubing annulus passage before the production tree is installed. After the tree is installed, the operator retrieves the plug with a wireline retrieval tool. Sometimes a tubing annulus valve is installed in a line that communicates with the tubing annulus passage for controlling flow to and from the annulus. In some subsea installations, the line is ported around the tubing hanger through the body of a tubing head spool or horizontal tree. In this case, the annulus valves are controlled by ROV, WOCS or from the tree mounted control system when the production controls umbilical is in place. 
       SUMMARY OF THE INVENTION 
       [0006]    Disclosed herein are example methods and devices for remotely providing access to an annulus within a subsea wellbore. In one example, a subsea assembly includes an annular outer wellhead member, an annular inner wellhead member insertable within the outer wellhead member, a tubular string depending from the inner wellhead member, an annulus circumscribing the tubular string, a flow line having an end intersecting the annulus, and a valve in the flow line selectively moveable between an open position to a closed position. In this example, an actuator is coupled to the valve and is in communication with a motive source through a passage formed through the outer tubular and the inner tubular. The outer wellhead member can be a tubing head spool, the inner wellhead member can be a tubing hanger laudable in the tubing head spool, and the tubular string can be production tubing. In an example, the motive source can be one of a supply of hydraulic fluid or an electrical power source. The subsea assembly can further include an outer seal assembly in a portion of the passage in the outer wellhead member and an inner seal assembly in a portion of the passage in the inner wellhead member that communicate with one another when the inner wellhead member lands in the outer wellhead member. Alternatively, the valve is actuatable by a remotely operated vehicle. The inner wellhead member can be selectively connected to be part of a landing string, and wherein the passage extends through the landing string. In this example, the inner wellhead member is a tubing hanger, and the landing string is made up of a tubing hanger, a running tool, and a subsea test tree. 
         [0007]    Also disclosed herein is a subsea assembly that includes a tubing head spool mounted over a wellbore and a landing string. The landing string includes a subsea test tree, a running tool connected to the subsea test tree, and a tubing hanger connected to the running tool and selectively insertable in the tubing head spool. Also included is an annulus access line having a portion projecting through the tubing spool, a valve in-line with the annulus access line and that is moveable between an open position and a closed position, and an actuator coupled to the valve and connected to a power source by a line extending through the landing string and tubing head spool. In an alternate embodiment, the landing string lands in the tubing head spool, and an annulus is formed around a lower portion of the tubing hanger that is accessible through the annulus access line. Portions of the line in the tubing head spool and tubing hanger can be passages formed in the tubing head spool and tubing hanger. In this example, further included is a seal assembly in the passage in the tubing hanger that selectively changes from a closed to an open configuration when the tubing hanger is landed in the tubing head spool. The subsea assembly can further include a plurality of passages in the tubing hanger that register with and are in communication with passages formed in the running tool. In this example, at least one of the passages contain an electrical line and wherein a fluid flows through at least another one of the passages. 
         [0008]    Also disclosed is a method of handling a subsea assembly, where the subsea assembly includes a landing string having a tubing hanger. The method includes lowering the landing string subsea and landing the tubing hanger within a tubing spool, and selectively opening an annulus access valve to provide communication to an annulus circumscribing the tubing by communicating a motive source along a path that extends through the landing string. The motive source can be hydraulic fluid communicated to an actuator that is connected to the annulus access valve. Optionally, the motive source can be electricity communicated to an actuator that is connected to the annulus access valve. The method may further include closing the annulus access valve. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0009]    Some of the features and benefits of the present invention having been stated, others will become apparent as the description proceeds when taken in conjunction with the accompanying drawings, in which: 
           [0010]      FIG. 1  is a side sectional view of an example of landing a tubing hanger with a running tool in accordance with the present invention. 
           [0011]      FIG. 2  is an enlarged view of a portion of an example of the tubing hanger and running tool of  FIG. 1 . 
       
    
    
       [0012]    While the invention will be described in connection with the preferred embodiments, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications, and equivalents, as may be included within the spirit and scope of the invention as defined by the appended claims. 
       DETAILED DESCRIPTION OF INVENTION 
       [0013]    The method and system of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings in which embodiments are shown. The method and system of the present disclosure may be in many different forms and should not be construed as limited to the illustrated embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey its scope to those skilled in the art. Like numbers refer to like elements throughout. 
         [0014]    It is to be further understood that the scope of the present disclosure is not limited to the exact details of construction, operation, exact materials, or embodiments shown and described, as modifications and equivalents will be apparent to one skilled in the art. In the drawings and specification, there have been disclosed illustrative embodiments and, although specific terms are employed, they are used in a generic and descriptive sense only and not for the purpose of limitation. 
         [0015]    An example of a wellhead assembly  10  being assembled is shown in a side sectional view in  FIG. 1 . The wellhead assembly  10  is being formed on a seafloor  112  and set over a wellbore  14  shown intersecting a formation  16  beneath seafloor  12 . An annular wellhead housing  18  makes up a lower most portion of the wellhead assembly  10 , and is shown anchored into the seafloor  12 . An annular casing spool  20  coaxially mounts on an upper end of the wellhead housing  18 , in which a casing hanger  22  is supported. Casing hanger  22  is a generally annular member, and has an oblique profile on its outer radius that lands in complimentary profiles within an inner surface of casing spool  20 . A casing string  24  attaches on a lower end of casing hanger  22  and depends downward into wellbore  14 . An annular tubing head spool  26  is illustrated mounted on an upper end of casing spool  20 ; and similar to casing spool  20 , tubing head spool  26  has an inner radius with profiles on which a complimentary shaped tubing hanger  28  is being landed. A tubing string  30  couples to a lower end of tubing hanger  28  and coaxially inserts within casing hanger  22  below. Tubing string  30  projects further downward to within casing string  24 . In the example of  FIG. 1 , tubing hanger  28  is part of a landing string  31  that includes a running tool  32  for attachment into the tubing hanger  28 , and a subsea test tree  33  coupled to an upper end of running tool  32 . 
         [0016]    A portion of the wellhead assembly  10  is illustrated in  FIG. 2  in an enlarged and side sectional view, where connection between running tool  32  and tubing hanger  28  is seen. In the example of  FIG. 2 , a series of passages  34 ,  36 ,  38 ,  40 ,  42 ,  44 ,  46 ,  48 ,  50  extend axially through the running tool  32 . Shown formed axially from an upper end of tubing hanger  28  and within the body of tubing hanger  28  are passages  54 ,  56 ,  58 ,  60 ,  62 ,  64 ,  66 ,  70 . The series of passages  34 ,  36 ,  38 ,  40 ,  42 ,  44 ,  46 ,  48 ,  50  respectively register with passages  54 ,  56 ,  58 ,  60 ,  62 ,  64 ,  66 ,  70  via connectors  72 ,  74 ,  76 ,  78 ,  80 ,  82 ,  84 ,  86 ,  88 . Thus, by connecting the running tool  32  with tubing hanger  28 , immediate communication and registration occurs between the respective passages in running tool  32  and tubing hanger  28 . 
         [0017]    Further illustrated in  FIG. 2  are a pair of annulus access valves  90 ,  92  mounted in a portion of a line  94  shown outside of tubing head spool  26 . Line  94  communicates with an annulus  96  formed in a space between tubing hanger  28  and casing spool  20 . Line  94  may extend through a passage  97  formed in the side wall of tubing head spool  26 , or may be piped up to the passage  97 . Fittings  98 ,  100  are provided respectively on valves  90 ,  92 , so that valves  90 ,  92  may be operated subsea by a remotely operated vehicle (ROV)  102 . As is known, opening and closing of valves  90 ,  92  selectively provides access to annulus  96  for various workover and/or completion efforts that take place during the course of completing and/or operating a well. 
         [0018]    In the example of  FIG. 2 , an actuator  104  is provided with valve  92  for selective opening and closing of valve  92 . A motive source, such as hydraulic fluid or electricity, is provided to actuator  104  via line  106  shown projecting through the side wall of the tubing head spool  26  and into communication with passage  70 . A connector  108  provides communication between line  106  and passage  70 , which in one example may include a spheriseal assembly. An example of a spheriseal considered for use herein is described in Miller, U.S. Patent Application Publication No. U.S. 2013/0056219, which is assigned to the assignee of the present application, and incorporated for reference in its entirety for all purposes herein. Optionally, a line, wire, or tubing may be included in passage  70  for conveying the motive source through the tubing hanger  28  into line  106 . 
         [0019]    Further in the example of  FIG. 2 , line  106  connects with or projects through passage  110 , shown formed in the sidewall of the tubing head spool  26 . Passage  110  terminates adjacent tubing hanger  28  where it registers with connector  108 . Optionally, the portion of passage  110  adjacent tubing hanger  28  can be a gallery  111  which circumscribes the inner surface of tubing head spool  26 . As discussed above, passage  70  communicates with passage  50  shown in running tool  32 . A power source  112  is schematically illustrated, which can be a hydraulic pump, a reservoir of hydraulic fluid, as well as an electrical power source. Line  114  attached to power source  112  conveys motive source from power source  112  to a designated destination. Power source  112  can be located above the sea surface and communicate with the wellhead assembly  10  ( FIG. 1 ) through landing string  31  ( FIG. 1 ). In an example, line  114  is in communication with passage  50  through a circuit (not shown) between power source  112  and landing string  31 . As indicated above, passage  50  is in communication with passage  70  via connector  88 , and passage  70  is in communication with line  106  through connector  108 . Accordingly, power source  112  is in communication with actuator  104 , and selective delivery of a motive source from power source  112  to actuator  104  can open or close annular access valve  92 . In this manner, annulus access valve  92  can be controlled from a control room or other area where landing operations are being managed by allowing for actuation of the annular access valve  92  from above the sea surface. An advantage of automating operation of the annular access valve  92  is that ROV  102  is no longer necessary for providing access to annulus  96 . 
         [0020]    In one example of operation, landing string  31  is formed, and tubing hanger  28  and tubing  30  is suspended from running tool  32 . As noted above, connecting tubing hanger  28  with running tool  32  registers series of passages  34 ,  36 ,  38 ,  40 ,  42 ,  44 ,  46 ,  48 ,  50  with passages  54 ,  56 ,  58 ,  60 ,  62 ,  64 ,  66 ,  70 . Power source  112  is in communication with passage  50  in running tool  32  through line  114  and connections (not shown) between line  114  and passage  50 . Landing the tubing hanger  28  within tubing head spool  26  puts passage  70  in communication with passage  110 , thereby completing a circuit through which power source  112  communicates with actuator  104 . Power source  112  can optionally be controlled by a controller  116 , which can be an information handling device with memory for storing commands for automated operation. Controller  116  can also represent a means by which an operator can send commands to power source  112 , where in an example the operator is in a rig, ship, or other vessel disposed on sea surface above the tubing head spool  26 . A communication means  118  provides a link for communicating between controller  116  and power source  112 , which can include hard wiring, electromagnetic waves, or acoustic signals. As such, an operator can control operation of annulus access valve  92  while in a vessel located on sea surface. 
         [0021]    Embodiments exist wherein an actuator (not shown) is provided for annulus access valves  90 . In addition to selective opening and closing of valve  92  via the landing string  31 , emergency shutdown procedures may be formed in this manner through the landing string  31 . Similarly, valves on horizontal trees may be controlled through the landing string control system. An advantage of annular access valve control through the landing string control system allows all functions necessary for an intervention to be controlled from a single system. This single path of control signals allows automatic sequenced closer of valves associated with the wellhead assembly  10  during an emergency shutdown and for the system to be moved into a failsafe configuration in the event of unintended disconnect or loss of control. 
         [0022]    The present invention described herein, therefore, is well adapted to carry out the objects and attain the ends and advantages mentioned, as well as others inherent therein. While a presently preferred embodiment of the invention has been given for purposes of disclosure, numerous changes exist in the details of procedures for accomplishing the desired results. These and other similar modifications will readily suggest themselves to those skilled in the art, and are intended to be encompassed within the spirit of the present invention disclosed herein and the scope of the appended claims.