Abstract:
A production tubing assembly for accessing multiple boreholes includes an outer shroud having an axial throughbore, a deflector disposed in the axial throughbore and releasably coupled to the outer shroud, and at least two tubular members releasably coupled to the deflector by extendable latch assemblies, wherein the deflector with the coupled tubular members is extendable from within the outer shroud to a position beyond the outer shroud, wherein, in the extended position, the latch assemblies extend to release the tubular members and latch the deflector to the outer shroud.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application claims the benefit of U.S. Provisional Application Ser. No. 61/142,112, filed Dec. 31, 2008, entitled Dual Production String Apparatus. 
     
    
     BACKGROUND 
       [0002]    This disclosure relates generally to hydrocarbon exploration and production, and in particular, to managing placement of wellbore tubulars in a borehole to facilitate hydrocarbon exploration and production. 
         [0003]    A borehole may be drilled into the ground to explore and produce a hydrocarbon reservoir therein. This borehole may be referred to as the main or primary borehole. To further explore and/or increase production from the reservoir, one or more lateral boreholes may be drilled which branch from the main borehole. Such drilling extends the reach of the well into laterally displaced portions of the reservoir. During downhole operations, it may be necessary to separately and selectively enter the main and lateral boreholes with a wellbore tubular or tubulars. The wellbore tubulars, or tubing strings, can be used to establish flow or access paths in the multiple boreholes. For example, production strings can be guided to the main and lateral boreholes, and sealed, to provide fluid flow paths from the multiple boreholes into the primary well extending to the surface. 
         [0004]    The principles of the present disclosure are directed to overcoming one or more of the limitations of the existing apparatus and processes for providing production access to multiple boreholes. 
       SUMMARY 
       [0005]    An embodiment of a production tubing assembly for accessing multiple boreholes includes an outer shroud having an axial throughbore, a deflector disposed in the axial throughbore and releasably coupled to the outer shroud, and at least two tubular members releasably coupled to the deflector by extendable latch assemblies, wherein the deflector with the coupled tubular members is extendable from within the outer shroud to a position beyond the outer shroud, wherein, in the extended position, the latch assemblies extend to release the tubular members and latch the deflector to the outer shroud. The deflector may extend toward a junction with a main borehole and a lateral borehole. The tubular members may be further extendable into the main and lateral boreholes. The deflector may be releasably coupled to the outer shroud by shear members. The latch assemblies may include spring-loaded latch members. The latch members may include an outer latch surface and an inner tubular gripping surface. The latch members, in the extended position, may expand into recesses in the outer shroud. The assembly may further include a wicker assembly coupled between the tubular members and the outer shroud for one directional movement of the tubular members relative to the outer shroud. The wicker assembly may allow downward movement of the tubular members and prevent upward movement of the tubular members for retrieval of the assembly. The wicker assembly may include spring-loaded ratchet members. The ratchet members may include gripping surfaces and the tubular members may include mating gripping surfaces to form a uni-directional gripping interface. The deflector may be aligned in the main borehole and slidingly received by an integral deflector in the main borehole. The deflector may include a ramp to deflect one of the tubular members into the lateral borehole. 
         [0006]    An embodiment of a production tubing assembly for accessing multiple boreholes includes an outer shroud having an axial throughbore and an inner recess, a deflector slidably disposed in the axial throughbore and releasably coupled to the outer shroud, at least two tubular members supported by the deflector, and a latch assembly disposed in a portion of the deflector between the outer shroud and the two tubular members, the latch assembly comprising at least one latch member having a tubular gripping surface and a latch surface to engage the inner recess of the outer shroud. The deflector may include a retracted position wherein the outer shroud forces the latch member gripping surface into engagement with one of the tubular members, and an extended position wherein the latch member is biased into the inner recess of the outer shroud to release the gripping surface from the tubular member and latch the deflector to the outer shroud. The assembly may further include a wicker assembly coupled between at least one of the tubular members and the outer shroud, the wicker assembly including at least one ratchet member having a gripping surface mating with a gripping surface of the tubular member to form a uni-directional gripping interface. 
         [0007]    A method for accessing multiple boreholes with a production tubing assembly includes lowering the tubing assembly into a primary well, wherein the tubing assembly comprises a deflector coupled to an outer shroud and at least two tubular members coupled to the deflector, disposing the tubing assembly adjacent a junction between a main borehole and a lateral borehole, releasing the deflector from the outer shroud, extending the deflector and the tubular members from the outer shroud, releasing the tubular members from the deflector, latching the deflector to the outer shroud, and extending the tubular members into the main and lateral boreholes. 
         [0008]    The method may further include coupling the deflector to the outer shroud with shear members, and wherein releasing the deflector from the outer shroud comprises shearing the shear members. The method may further include coupling the two tubular members to the deflector with latch members having gripping surfaces, and wherein releasing the tubular members from the deflector and latching the deflector to the outer shroud comprises biasing the latch members away from the tubular members and into recesses in the outer shroud. The method may further include lifting the two tubular members, and retrieving the tubing assembly to the surface of the primary well. Retrieving the tubing assembly to the surface of the primary well may further include coupling a wicker assembly between the two tubular members and the outer shroud, and wherein the wicker assembly comprises a uni-directional gripping interface with the tubular members allowing downward movement of the tubular members relative to the outer shroud and preventing upward movement of the tubular members relative to the outer shroud. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    For a more detailed description of the embodiments of the present disclosure, reference will now be made to the accompanying drawings, wherein: 
           [0010]      FIG. 1  is a schematic view of a system for milling and drilling a lateral borehole from a primary borehole; 
           [0011]      FIG. 2  is a schematic view of the finished junction between the lateral borehole and the primary borehole including downhole operations equipment; 
           [0012]      FIG. 3  is a schematic view of an embodiment of a deflector and multiple tubing string assembly in accordance with principles herein disposed in the junction of  FIG. 2 ; 
           [0013]      FIG. 4  is a side, elevation view of an embodiment of a production string assembly in accordance with principles herein; 
           [0014]      FIG. 5  is an enlarged, cross-section view of a shroud portion of the production string assembly of  FIG. 4 ; 
           [0015]      FIG. 6  is a radial section view of the shroud portion of  FIGS. 4 and 5  showing the aligned tubing deflector and production strings; 
           [0016]      FIG. 7  is side view of the shroud portion of  FIGS. 4 and 5  with a tubing deflector extended therefrom; 
           [0017]      FIG. 8  is a top view of the shroud assembly in detail; 
           [0018]      FIG. 9  is a side cross-section view of the shroud assembly of  FIG. 8 ; 
           [0019]      FIG. 10  is a side view of the shroud assembly of  FIG. 8 ; 
           [0020]      FIGS. 11 and 13  are cross-section views of a retracted position of an upper end of the tubing deflector including tubing and shroud latch assemblies; 
           [0021]      FIGS. 14 and 17  are radial section views of the deflector and latch assemblies of  FIGS. 11 and 13 ; 
           [0022]      FIGS. 12 and 15  are cross-section views of an extended position of the deflector and latch assemblies of  FIGS. 11 and 13 ; 
           [0023]      FIG. 16  is a radial section view of the deflector and latch assemblies of  FIGS. 12 and 15 ; 
           [0024]      FIG. 18  is a section view of the gripping interface between the latch and the tubular member of the previous figures; 
           [0025]      FIGS. 19-21  are various views of the latches of the previous figures; 
           [0026]      FIG. 22  is a perspective view of the upper end of the tubing deflector of the previous figures; 
           [0027]      FIGS. 23 and 24  are cross-section views of a wicker assembly, taken in a different plane than the view of  FIG. 11 ; 
           [0028]      FIGS. 25 and 26  are radial section views of the wicker assembly of  FIGS. 11 ,  23  and  24 ; 
           [0029]      FIG. 27  is an isolated perspective view of the wicker assembly support members; 
           [0030]      FIG. 28  is an isolated perspective view of the wicker assembly ratchet members; and 
           [0031]      FIGS. 29-45  are various assembly and operational views of the embodiments of the deflector and multiple tubing string assembly during use. 
       
    
    
     DETAILED DESCRIPTION 
       [0032]    In the drawings and description that follow, like parts are typically marked throughout the specification and drawings with the same reference numerals. The drawing figures are not necessarily to scale. Certain features of the invention may be shown exaggerated in scale or in somewhat schematic form and some details of conventional elements may not be shown in the interest of clarity and conciseness. The present invention is susceptible to embodiments of different forms. Specific embodiments are described in detail and are shown in the drawings, with the understanding that the present disclosure is to be considered an exemplification of the principles of the invention, and is not intended to limit the invention to that illustrated and described herein. It is to be fully recognized that the different teachings of the embodiments discussed below may be employed separately or in any suitable combination to produce desired results. 
         [0033]    In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . ”. Unless otherwise specified, any use of any form of the terms “connect”, “engage”, “couple”, “attach”, or any other term describing an interaction between elements is not meant to limit the interaction to direct interaction between the elements and may also include indirect interaction between the elements described. The terms “pipe,” “tubular member,” “casing” and the like as used herein shall include tubing and other generally cylindrical objects. In addition, in the discussion and claims that follow, it may be sometimes stated that certain components or elements are in fluid communication or fluidly coupled. By this it is meant that the components are constructed and interrelated such that a fluid could be communicated between them, as via a passageway, tube, or conduit. The various characteristics mentioned above, as well as other features and characteristics described in more detail below, will be readily apparent to those skilled in the art upon reading the following detailed description of the embodiments, and by referring to the accompanying drawings. 
         [0034]    Referring initially to  FIG. 1 , a primary or main borehole  30  is drilled in a conventional manner and may include operational equipment  60 , such as a whipstock and anchor system, and  70 , such as a fracturing or production system. A diverter or whipstock  45  is used to guide a milling and/or drilling assembly  50  laterally relative to the primary borehole  30  for creating a lateral or secondary borehole  40  having a junction  35  with the primary borehole  30 . Referring now to  FIG. 2 , the finished junction  35  and lateral borehole  40  are shown. Well treatment, completion or production equipment  70  may remain in the primary borehole  30  along with an orientator or locator  62  for receiving additional downhole tools. 
         [0035]    Referring next to  FIG. 3 , a production tubing system or assembly  100  is shown in accordance with the principles of the present disclosure. The production tubing assembly  100  is adapted for providing a pressure seal, which isolates the lateral borehole  40  from the main borehole  30  and vice versa, to the two (or multiple) bores for production access. Because the production tubing assembly is a junction block, it may also be referred to as a Y-block  100 . The Y-block  100  is also designed to provide a stackable level  5  junction. In some embodiments, the Y-block apparatus  100  self aligns on a mule shoe downhole and latches to the top of the junction  35 . When latched, a deflector with dual strings  102 ,  104  attached advances into the junction  35 . Once the deflector is in place in the junction  35 , the deflector selectively guides the strings  102 ,  104  into the main and lateral bores. The string  102  lands in a polished bore receptacle  72  of the production equipment  70  and the string  104  lands in a polished bore receptacle  82  of production equipment  80 . For purposes of simplicity and clarity, the strings  102 ,  104  and the equipment  70 ,  80  will be referred to as production strings and equipment, though other tubular members and downhole equipment are contemplated. The positioned assembly  100  and production strings  102 ,  104  will effect a seal in the bores of the production equipment  70 ,  80  in the main and lateral bores to complete the well. A packer assembly  95  and other downhole equipment may also be provided in the boreholes  30 ,  40 . 
         [0036]    In some embodiments, a diverter  108  is disposed at the top of the Y-block  100  that selectively allows access to either bore for future intervention work needed downhole. The diverter  108  may stay in place and can be rotated by means of multi-cycle “J” grooves to allow access to the desired bore. A packer  106 , with a seal bore receptacle, is set at the top of the Y-block apparatus  100  to lock the assembly in place. If another junction is created in the main borehole  30  above the original junction  35 , a packer is provided to seal access to the lower junction  35 , making the Y-block  100  stackable. Additional details regarding the components of the Y-block  100  and its operation are discussed below, showing that the apparatus  100  allows multiple production strings to be selectively and controllably guided to the lateral and main bores, and that the in place diverter allows the Y-block system to be stacked on top of another in the well. 
         [0037]    Referring now to  FIG. 4 , a side elevation view of the multiple production string assembly  100  is shown. An upper end of the assembly  100  includes the packer  106 , followed by the diverter  108 , the tubing strings  102 ,  104  and an outer shroud  110 . In some embodiments, the diverter  108  is disposed above the packer  106  and is separately retrievable consistent with other teachings herein. As shown in the cross-section view of  FIG. 5 , the shroud  110  houses ends of the adjacent tubing strings  102 ,  104  which are supported by a tubing deflector  112 . The radial section view of the shroud  110  as shown in  FIG. 6  illustrates the tubing deflector  112  having an alignment feature  114  and supporting the tubing strings  102 ,  104 . Referring to  FIG. 7 , the tubing deflector  112  is shown in an extended position beyond an end  116  of the shroud  110 . 
         [0038]    Referring now to  FIGS. 8-10 , the shroud  110  is isolated and shown in detail.  FIG. 8  shows a top view of the shroud  110  including the end  116  for mating with a downhole mule shoe or other locator.  FIG. 9  shows a side, cross-section view of the shroud  110  revealing the inner tubing strings  102 ,  104  and supporting deflector  112 .  FIG. 10  shows a side view of the shroud  110 , with various cross-sectional lines shown for subsequent figures. 
         [0039]    Referring to  FIGS. 11-18 , an upper end  122  of the tubing deflector  112  is shown. In  FIGS. 11 and 13 , a cross-section of the upper end  122  of the deflector  112  is shown disposed in the shroud  110  in the run-in or retracted position of  FIG. 5 . Spring-loaded latches  118  are disposed in pockets  140  in the deflector  112  and forced radially inward by the inner surface of the shroud  110 . The latches  118  include an outer surface  130 , a tapered surface  132  and a retaining pin  134  extending through a central bore. The radial section views of  FIGS. 14 and 17  also show the latches  118  pressed radially inward by the shroud  110 . Further, the latches  118  include gripping surfaces  136  for engaging the tubular members  102 ,  104  and preventing premature movement of the tubular members  102 ,  104  while the deflector  112  is in the retracted position. Referring briefly to  FIG. 18 , a section view shows the interface between the gripping surfaces  136  of the latches  118  and mating gripping surfaces  103  of the tubular members.  FIGS. 14 and 17  also show that the deflector  112  is retained in the retracted position by a series of shear pins  128  disposed through the shroud  110  and into the deflector  112 . 
         [0040]    When the tubing deflector  112  is moved to its fully extended position, as shown in  FIG. 7 , the latches  118  are positioned adjacent recesses  120 , as shown in  FIGS. 12 ,  15  and  16 . The spring-loaded latches  118  are now allowed to expand into the recesses  120 , thereby shouldering against the recesses  120  as shown in  FIG. 15  and preventing the deflector  112  from upward movement back into the shroud  110 . Also, as shown in  FIG. 16 , the gripping surfaces  136  are released from engagement with the tubular members  102 ,  104 . Thus, the latches  118  prevent movement of the tubular members  102 ,  104  during movement of the deflector  112  from the retracted position to the fully extended position, whereupon the latches  118  release the tubular members  102 ,  104 . As shown in  FIG. 12 , a shoulder  124  on the deflector  112  can engage a shoulder  126  on the shroud  110  to prevent the deflector  112  from extending further in a downward direction. 
         [0041]    Referring now to  FIGS. 19-22 , the latches  118  are shown in further detail.  FIG. 19  shows the top surfaces  130 ,  132  for contacting the shroud  110 , and the central bore  138  for receiving the pin  134  that moveably retains the latch  118  for the spring-loaded action of the latch  118 .  FIG. 20  shows the lower gripping surfaces  136 .  FIG. 21  shows the upper surfaces  130 ,  132 , the lower gripping surfaces  136  and the central bore  138 .  FIG. 22  shows the upper end  122  of the deflector  112  including the pocket  140  for the latch  118  and axial bores  142 ,  144  to receive the tubing strings  102 ,  104 . 
         [0042]    Referring back to  FIG. 11 , a wicker assembly  150  is provided between the shroud  110  and the tubular members  102 ,  104  just above the upper end  122  of the deflector  112  in the retracted position. The wicker assembly  150  includes support members  152  coupled to the shroud  110  with bolts  154 . The tubular string  102  is provided with a gripping surface  160 . Referring now to  FIGS. 23 and 24 , another cross-section of the assembly  100  in a slightly different plane than that of  FIG. 11  shows that the wicker assembly  150  includes ratchet members  156  moveably coupled to the support members  152  by pins  162 . The pins  162  allow radial movement of the ratchet members  156 , and springs  164  are provided between the ratchet members  156  and the support members  152  to provide a biasing force toward the tubing string  102 . The ratchet members  156  include gripping surfaces  158 , and a portion of the tubing string  102  is provided with a gripping surface  160 . The gripping surfaces  158 ,  160  are designed such that when they come together in a mating relationship, the interface  159  formed thereby and maintained by the spring-loaded ratchets  156  allow relative movement of the tubing string  102  in only one direction. 
         [0043]    Referring to  FIGS. 25 and 26 , a radial section of the wicker assembly  150  shows that the support members  152  are coupled to the shroud  110  by the bolts  154 , and the ratchet members  156  are moveably coupled to the support members  152  by the pins  162  and spring-loaded to form a uni-directional gripping interface  159  between the gripping surfaces  158 ,  160 . Thus, the tubing strings  102 ,  104  can only move in one direction relative to the shroud  110  when the appropriate force is applied. Typically, this movement will be downward toward the main and lateral boreholes for entry into the boreholes. Upward movement of the tubing strings  102 ,  104  will be prevented, thus making the wicker assembly  150  a retrieval device for the Y-block  100 . The tubing strings  102 ,  104  may be lifted to return the assembly  100  to the surface.  FIG. 27  shows an isolated perspective view of the support members  152 .  FIG. 28  shows an isolated perspective view of the ratchet members  156  having gripping surfaces  158 . 
         [0044]    In operation, the production tubing assembly  100  is lowered into the primary borehole where a mule shoe or other locator  200  is secured, as shown in  FIG. 29 . The mule shoe  200  includes a profile  202  and collets snaps  204 . The assembly  100  is lowered toward the mule shoe  200 , with the assembly  100  including the end  116  with a mating mule shoe profile and a receptacle  117 . As shown in  FIG. 30 , the profiles  116 ,  202  mate to orient and secure the assembly  100  in the borehole. Collets  204  snap into the receptacle  117 . A cross-section view of the connection in  FIG. 30 , as shown in  FIG. 31 , illustrates the retracted position of the deflector  112  and tubing  102  assembly in the shroud  110 . Upon application of a force or set down weight on the deflector and tubing assembly via the production tubings, the shear pins  128  ( FIG. 14 ) are sheared and the deflector  112  with coupled tubulars  102 ,  104  begins to advance toward the junction  35  and the main and lateral bores, as shown in  FIG. 33 . In  FIG. 34 , the Y-block deflector  112  is shown continuing to advance toward the junction  35 . In  FIG. 35 , the deflector  112  has advanced into the junction  35 , bringing the tubing strings  102 ,  104  along behind it. As shown in  FIG. 36 , the deflector  112  has been fully extended into the junction  35 . The main borehole may be provided with an integral deflector  94 . 
         [0045]    Referring to  FIG. 37 , the fully extended Y-block tubing deflector assembly is shown in a perspective view. The main borehole  30  includes the integral deflector  94  which has received the Y-block deflector  112 . The deflector  112  houses the main bore tubing string  102 , and also provides a ramp  105  for supporting the lateral tubing string  104  adjacent the string  102 . A cross-section view of the fully extended deflector assembly is shown in  FIG. 38 , including the main bore  30  with the integral deflector  94 , the lateral bore  40  and the deflector  112  housing the main tubular string  102  and having the ramp  105 . As shown in  FIG. 39 , and previously described with respect to  FIGS. 12 ,  15  and  16 , the spring-loaded latches  118  are forced into the recesses  120  to, first, prevent upward movement of the deflector  112 , and, second, release the tubing string  102  for advancement into the lower boreholes  30 ,  40 . Now, as shown in  FIGS. 40 and 41 , a force or set down weight is again applied to the tubing strings  102 ,  104  such that they are advanced into their respective boreholes for mating engagement with the polished bore receptacles  72 ,  82  ( FIG. 3 ). 
         [0046]    With reference to  FIGS. 42-45 , more detailed views of the fully extended deflector and tubing assembly inside the borehole junction can be seen pursuant to the description provided above. The tubing and deflector assembly  100  is engaged with the mule shoe  200  at the mating orientation profiles  116 ,  202  and the collets  204  snapped into the receptacles  117 . A cross-section at  42   a - 42   a  depicts a bottom-up view of the assembly  100  disposed in the junction between boreholes  30 ,  40 , wherein the deflector  112  and other components are arranged as shown in  FIG. 42   a . As shown in  FIG. 43 , a cross-section at an upper end of the assembly illustrates the side-by-side or adjacent tubulars  102 ,  104  supported and separated by the deflector  112  disposed in the shroud  110 . In  FIG. 44 , an intermediate cross-section shows the tubular  102  and the deflector  112  disposed in the junction between boreholes  30 ,  40 . The deflector  112  includes a ramp  105  for receiving and guiding the tubular  104 . In  FIG. 45 , a lower cross-section depicts the deflector  112  encompassing the tubular  102  while the deflector  112  has also been guided through a central passageway of the integral deflector  94  anchored in the primary borehole  30 . 
         [0047]    As shown in  FIGS. 37 and 45 , the deflector  112  is aligned in the borehole using its shape and interaction with other components. For example, a lower lobe  109  of the deflector  112  slidingly mates with a central passageway  97  of the integral deflector  94 . Thus, the several features described herein provide a self-aligning deflector and tubing assembly for inserting multiple tubulars into multiple boreholes for production access. 
         [0048]    The embodiments set forth herein are merely illustrative and do not limit the scope of the disclosure or the details therein. It will be appreciated that many other modifications and improvements to the disclosure herein may be made without departing from the scope of the disclosure or the inventive concepts herein disclosed. Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, including equivalent structures or materials hereafter thought of, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirements of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.