Abstract:
A technique facilitates connection of tubulars along a tubing string via a linear motion. A first tubular is provided with a first connector end having a non-circular transverse cross-section, and a second tubular is provided with a second connector end having a corresponding non-circular transverse cross-section. The non-circular cross-section and the corresponding non-circular cross-section are designed to matingly engage when the first and second tubulars are moved linearly toward each other to form a tubing string. A seal is provided to seal the first connector end with the second connector end once linearly engaged. A locking mechanism may be employed to linearly lock the first connector end with the second connector end.

Description:
BACKGROUND 
       [0001]    In a wide range of well applications, tubulars are joined together and coupled with various equipment to construct tubing strings. The tubing strings may be used in downhole completions and in a variety of service and production procedures. Generally, the tubular components are joined together via threaded connectors in which the tubular components are rotated relative to each other to form the connection before being run downhole. In some applications, the relative rotation utilized to form the connection can limit the utility of the tubing string and/or increase the difficulty of using certain components or performing certain procedures. 
       SUMMARY 
       [0002]    In general, a system and methodology are provided for connecting tubing components with a linear motion. A first tubular is provided with a first connector end having a non-circular transverse cross-section, and a second tubular is provided with a second connector end having a corresponding non-circular transverse cross-section. The non-circular cross-section and the corresponding non-circular cross-section are designed to matingly engage when the first and second tubulars are moved linearly toward each other to form a tubing string. A seal is provided to seal the first connector end with the second connector end once linearly engaged. A locking mechanism may be employed to linearly lock the first connector end with the second connector end. 
         [0003]    However, many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]    Certain embodiments of the disclosure will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements. It should be understood, however, that the accompanying figures illustrate the various implementations described herein and are not meant to limit the scope of various technologies described herein, and: 
           [0005]      FIG. 1  is a schematic illustration of a multilateral completion system deployed in a wellbore and comprising a plurality of linear connection systems, according to an embodiment of the disclosure; 
           [0006]      FIG. 2  is a cross-sectional view of an example of a linear connection system for connecting tubulars along the multilateral completion system, according to an embodiment of the disclosure; 
           [0007]      FIG. 3  is a cross-sectional view of another example of a linear connection system for connecting tubulars along the multilateral completion system, according to an embodiment of the disclosure; 
           [0008]      FIG. 4  is a cross-sectional view of another example of a linear connection system for connecting tubulars along the multilateral completion system, according to an embodiment of the disclosure; 
           [0009]      FIG. 5  is a cross-sectional view of an example of engaged connector ends of a linear connection system, according to an embodiment of the disclosure; 
           [0010]      FIG. 6  is an orthogonal view of an example of a connector end, according to an embodiment of the disclosure; 
           [0011]      FIG. 7  is an orthogonal view of an example of a corresponding connector end, according to an embodiment of the disclosure; and 
           [0012]      FIG. 8  is an illustration of a non-circular backup seal which may be employed in the linear connection system, according to an embodiment of the disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0013]    In the following description, numerous details are set forth to provide an understanding of some embodiments of the present disclosure. However, it will be understood by those of ordinary skill in the art that the system and/or methodology may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible. 
         [0014]    The disclosure herein generally involves a system and methodology related to connecting tubulars in a tubing string. Tubulars may comprise pipe/tubing sections and a variety of other components coupled together in a tubing string. By way of example, the system and methodology may be employed to connect two tubular components without using a threaded connection. As described below with respect to various embodiments, the connection can be formed through relative linear movement of the two tubular components. By enabling connection without rotation, the two tubulars being connected may be maintained in a specific alignment. Additionally, the tubulars or sections of the tubulars may use geometries other than a cylinder or cone to form the connection. 
         [0015]    This latter characteristic enables creation of space or room to bypass the tubulars, e.g. tubular tools, with a control line which may comprise electrical lines, fluid flow lines, optical fibers, and/or other types of communication lines. By facilitating the use of control lines, the connection system enables or at least simplifies the construction and operation of a wide range of equipment in multilateral completion applications. However, the linear connection system may be utilized for many types of other tubular systems in both well and non-well related applications. 
         [0016]    In certain embodiments, the tubular components to be joined have connector ends which have non-circular cross-sectional features. For example, one tubular may have an oblong connector end sized for sliding receipt in a corresponding oblong interior or recess of the next adjacent tubular. When using such a non-circular shape instead of threaded connections, however, the present linear connection system maintains pressure integrity while still providing space for running control lines along the exterior of the tool. The non-circular features also provide torque resistance, thus allowing torque to be applied to the tubular components through the connection. 
         [0017]    Referring generally to  FIG. 1 , an embodiment of a system  20 , e.g. a well completion system, is illustrated as deployed in a wellbore  22  having, for example, a main bore  24  and a lateral bore  26 . Depending on the application, wellbore  22  may have multiple lateral bores  26 . Additionally, system  20  may comprise a variety of well systems utilizing joined tubular components. In some embodiments, system  20  may comprise tubular components employed in non-well related applications, e.g. surface tubing applications. In the example illustrated, well system  20  comprises a plurality of tubular components  28  which are joined by linear connection systems  30 . The tubular components  20  may comprise many types of tubing sections, tubular tools, and/or other tubular components which are coupled together to form an overall tubing string  32 . 
         [0018]    In the embodiment illustrated, the tubing string  32  comprises a plurality of the linear connection systems  30  which are indicated at connection regions  34 ,  36  and  38 , respectively. The connection regions  34 ,  36  and  38  along with the corresponding linear connection systems  30  are illustrated more clearly in  FIGS. 2-4 . Referring initially to  FIG. 2 , connection region  34  is illustrated as having first and second tubulars  28  coupled together to form a Y-block  40 . By way of example, one of the tubulars  28  may comprise a first connection end  42  slidably received by and engaged with a second connection end  44  of the next adjacent tubular  28 . In this embodiment, the first connection end  42  and the second connection end  44  are male and female ends, respectively, such that first connection end  42  is linearly and slidably engaged with second connection end  44 . As described in greater detail below, the transverse cross-section of first connection end  42  presents a non-circular shape, e.g. an oblong shape, which corresponds with a transverse, non-circular internal shape of second connection end  44 . The mating, non-circular shapes block relative rotation of the adjacent tubulars  28  and thus enable transmission of torque loading from one tubular  28  to the next adjacent tubular  28 . 
         [0019]    The tubulars  28  may be constructed in a variety of sizes and configurations. For example, one of the tubulars  28 , e.g. a first tubular  46 , may comprise a plurality of isolated flow passages  48 . In the specific example illustrated, the first tubular  46  comprises a pair of the flow passages  48  which allow for separated and isolated fluid flows along the tubing string  32 . In some applications, internal tubular components  50  or other internal components  50  may be deployed along one or more of the passages  48 . In this embodiment, the next adjacent tubular  28 , e.g. a second tubular  52 , comprises a single flow passage  54 . Depending on the application, the single flow passage  54  may commingle the flows from the plural passages  48 . In some applications, internal tubular structures  50  may be positioned to extend into and along flow passage  54  to maintain separation of fluid flows. The linear connection system  30  may be used to couple many types and configurations of adjacent tubulars  28 . As described herein, first tubular  46  and second tubular  52  may refer to either tubular  28  for a given linear connection system  30  and may comprise either male or female connection ends. 
         [0020]    Referring generally to  FIG. 3 , connection region  36  is illustrated as comprising another linear connection system  30 . In this embodiment, the linear connection system  30  again connects adjacent tubulars  28  by linearly joining first and second connection ends  42 ,  44 . A variety of other components may be used in combination with the tubulars  28 , e.g. in combination with first tubular  46  and second tubular  52 . For example, one of the internal tubular components  50  may comprise a window  56  and may be deployed internally within the Y-block  40 . The window  56  is oriented to enable intervention operations and/or other operations through a selected passage  48  of the plurality of passages  48  in first tubular  46 . 
         [0021]    Referring generally to  FIG. 4 , connection region  38  is illustrated as comprising another linear connection system  30 . In this embodiment, the linear connection system  30  again connects adjacent tubulars  28  by linearly joining first and second connection ends  42 ,  44 . A variety of other components, e.g. internal tubular components  50 , may again be employed within the connected tubulars  28 . The ability to form linear connections in constructing tubing string  32  facilitates the use of a wide variety of additional components, e.g. internal tubes or external control lines. The additional components may be positioned internally or externally with respect to the Y-block  40  or other linear connection systems  30 . 
         [0022]    In  FIG. 5 , an enlarged illustration of an example of linear connection system  30  is illustrated. In this embodiment, a seal system  58  and a locking mechanism  60  are positioned between first connector end  42  and second connector end  44 . For example, both the seal system  58  and the locking mechanism  60  are positioned radially or laterally between the connector ends  42  and  44 . By way of example, the seal system  58  may comprise a seal  62  and a backup ring or rings  64 . In many applications, seal  62  may comprise a standard O-ring style seal located in a groove formed in at least one of the connector ends, such as groove  66  formed in an interior surface of connector end  44 . 
         [0023]    The seal system  58  is designed to provide pressure integrity along the interior, e.g. along flow passages  48 ,  54 , of the first tubular  46  and the second tubular  52 . The locking mechanism  60  prevents inadvertent separation of the first connector end  42  from the second connector end  44 . In the example illustrated, the locking mechanism  60  is positioned radially or laterally between the first connector end  42  and the second connector end  44 . 
         [0024]    Although locking mechanism  60  may have a variety of forms, the illustrated embodiment utilizes a locking wire  68 . In the specific example illustrated, locking mechanism  60  comprises a plurality of locking wires  68  which lock the tubulars  46 ,  52  linearly after linear insertion of first connector end  42  into second connector end  44 . It should be noted that the non-circular shape of connector ends  42 ,  44  block relative rotation of the first tubular  46  with respect to the second tubular  52 . 
         [0025]    With additional reference to  FIGS. 6 and 7 , the first connector end  42  and the second connector end  44  may be formed with corresponding grooves  70 ,  72 , respectively. The grooves  70 ,  72  hold the corresponding locking wire or wires  68  so that the locking wires  68  provided an obstruction to separation of connector ends  42 ,  44 . The locking wires  68  may be fed into corresponding grooves  70 ,  72  through locking wire windows  74 , e.g. openings, after linear insertion of first connector end  42  into second connector end  44 . The windows  74  extend laterally through a sidewall of second connector end  44 , as illustrated in  FIG. 7 . It should be noted that locking mechanism  60  may utilize other components to provide the locking function. For example, instead of wires  68 , rods, ball bearings, or other components may be fed through windows  74  and into the corresponding grooves  70 ,  72  to prevent inadvertent separation of the joined tubulars  46  and  52 . 
         [0026]    Similarly, the seal system  58  may comprise a variety of seal components used at individual or multiple locations. By way of example, each seal location may utilize a combination of a resilient, elastomeric seal  62 , such as an O-ring, combined with an individual or a pair of backup seal rings  64 . As illustrated in  FIG. 8 , the backup ring or rings  64  may be formed, e.g. machined, from a relatively rigid material and each ring  64  may be pre-formed into a shape matching the cross-sectional shape of linearly engaged ends  42 ,  44 . In the specific example illustrated, the backup ring  64  comprises generally flat sides  76  which help provide support for the resilient, elastomeric seal  62 . 
         [0027]    Referring again to  FIGS. 6 and 7 , the tubulars  28 , e.g. first tubular  46  and second tubular  52 , may further comprise an external bypass slot  78 . In the specific example illustrated, the tubulars  46 ,  52  comprise a plurality of external bypass slots  78 . Each external bypass slot  78  is designed to carry a control line  80  or a plurality of control lines  80 , as indicated by dashed lines in  FIG. 7 . The control lines  80  may comprise electrical lines, fluid lines, fiber-optic lines, and various combinations of communication lines. For example, the control lines  80  may comprise electrical cables or hybrid cables carrying both electrical lines and other types of communication lines, e.g. fiber-optic lines and hydraulic lines. 
         [0028]    By forming the connector ends  42 ,  44  with a non-circular, transverse cross-sectional shape, e.g. an oblong shape, space is provided for the control lines  80 . In the embodiment illustrated, for example, the non-circular cross-section of connector ends  42 ,  44  provides generally flat sides which create room for external bypass slots  78 . As illustrated in  FIG. 6 , for example, first connector end  42  may be designed with an exterior  82  which in transverse cross-section has generally flat sides  84  joined by rounded ends  86 . The generally flat sides  84  create room for bypass slots  78 . Similarly, the second connector end  44  is designed to linearly receive first connector end  42  and has an interior surface  88  which in transverse cross-section has generally flat sides  90  joined by internal, rounded ends  92 . The generally flat sides  90  also create room for external bypass slots  78  as illustrated. Additionally, the corresponding non-circular, transverse cross-sectional shapes of ends  42 ,  44  may be used to facilitate proper orientation and alignment of flow passages  48  while providing torque resistance. The torque resistance allows torque on the tubulars  28  to be transmitted through the connection. 
         [0029]    The connector ends  42  and  44  may be designed to enable linear engagement of a wide variety of tubulars  28 . In the example illustrated in  FIGS. 5-7 , however, the connector ends  42  and  44  (along with first tubular  46  and second tubular  52 ) are designed to create a multilateral Y-block, e.g. Y-block  40 . The connector ends  42 ,  44  maintain alignment of the two “Y” legs of the Y-block throughout the tool while allowing for internal connections designed to facilitate manufacturing of the tubular components. The non-circular design may be used to reduce the tubular wall thickness, and the design also enables use of components, e.g. tubular components, which are non-cylindrical. 
         [0030]    As briefly described above, the non-circular geometry of the linear connection systems  30  facilitates introduction of the bypass slots  78  on either or both sides of the linear connection system  30 . The bypass slot or slots  78  may be used for intelligent well completion hardware, such as electrical cables or other control lines. This capability facilitates installation of, for example, intelligent control equipment below the Y-block  40 . 
         [0031]    The system  20 , e.g. well system, may be used in a variety of applications, including numerous well production and treatment applications as well as non-well related tubing applications. Depending on the specifics of a given tubing string, well application, and environment, the design of the overall system  20 , tubing string  32 , and linear connection system  30  may vary. Additionally, the system may be designed for use in many types of wells, including vertical wells and deviated, e.g. horizontal, wells. The wells may be drilled in many types of formations with single or multiple production zones. For example, multiple linear connection systems  30  may be in the form of multiple Y-blocks used to accommodate tubing structures in multiple lateral bores. 
         [0032]    Depending on the application, the linear connection system or systems  30  may be constructed in several configurations. For example, the transverse, cross-sectional shape of the connector ends may vary while still enabling linear engagement and restriction against relative rotational movement. Additionally, the tubulars forming each linear connection system may comprise individual internal flow passages or multiple, isolated flow passages to provide separate flows of fluid. The sealing system and locking mechanism also may vary. In wire-based locking mechanisms, for example, multiple wires may be employed or a single lock wire may be routed along a continuous groove. The external bypass slot or slots also may have a variety of shapes, depths, lengths, and configurations which utilize the space provided by the non-standard, e.g. non-circular, connection ends of each linear connection system  30 . The materials used to form the tubulars and the components used in cooperation with the tubulars also may vary widely depending on the specifics of a given application. 
         [0033]    Although a few embodiments of the disclosure have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this disclosure. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the claims.