Abstract:
A junction includes a borehole casing having a window therein; a diverter disposed within the casing and aligned and oriented with the window, the diverter having at least one profile along a longitudinal edge thereof; and a hanger assembly having a window therein, the window having an edge receivable by the at least one profile, the profile supporting the hanger assembly and method.

Description:
BACKGROUND 
       [0001]    In the hydrocarbon recovery industry, multilateral wells have become more and more used over the last decade or so. In each case of a lateral borehole extending from a primary borehole or from another lateral borehole, a natural junction is necessarily created in the formation. In the vernacular of the hydrocarbon recovery industry, the term “junction” usually refers to the man-made part of the well structure that is built into the natural junction to convey the targeted hydrocarbon to the surface. In some cases, the junction is intended to be a pressure competent structure, while in others there is no reason for the junction to contain pressure. In either type, there is an interest in the junction to be capable of withstanding formation collapse so that the well will function for its intended purpose, regardless of the collapse. Different materials have been used with inherent expense and thicker materials have been used, again with inherent expense. While such configurations can be effective in alleviating the effects of formation collapse to some extent, the added expense is undesirable and alternate configurations and methods are always well received by the art. 
       SUMMARY 
       [0002]    A junction includes a diverter having profiled longitudinal edges; and a hanger assembly configured to engage the profiled longitudinal edges. 
         [0003]    A method for improving collapse resistance of a junction includes disposing a diverter having a profiled longitudinal edge in a borehole at an intersection with a lateral borehole; and engaging a hanger assembly with the profiled longitudinal edge. 
         [0004]    A junction includes a borehole casing having a window therein; a diverter disposed within the casing and aligned and oriented with the window, the diverter having at least one profile along a longitudinal edge thereof; and a hanger assembly having a window therein, the window having an edge receivable by the at least one profile, the profile supporting the hanger assembly. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0005]    Referring now to the drawings wherein like elements are numbered alike in the several Figures: 
           [0006]      FIG. 1  is a perspective view of a first embodiment of the junction configuration as disclosed herein; 
           [0007]      FIG. 2  is a cross section view of  FIG. 1  taken along section line  2 - 2 ; 
           [0008]      FIG. 3  is a perspective view of a second embodiment of the junction configuration as disclosed herein; 
           [0009]      FIG. 4  is a cross section view of  FIG. 3  taken along section line  4 - 4 ; 
           [0010]      FIG. 5  is a perspective view of a third embodiment of the junction configuration as disclosed herein; 
           [0011]      FIG. 6  is a cross section view of  FIG. 5  taken along section line  6 - 6 . 
       
    
    
     DETAILED DESCRIPTION 
       [0012]    Initially, it will be helpful to point out that a part of the teaching hereof is to provide for support of a hanger assembly by a seal bore diverter instead of by a casing structure through which the hanger extends. Such a configuration allows one to take advantage of the excess strength that exists in the invariably thicker material of the seal bore diverter. Such support can be accomplished in several ways, the following embodiments being representative but not limiting. 
         [0013]    Referring to  FIGS. 1 and 2 , a junction  10  is illustrated in perspective view. A casing  12  of a primary bore, whether that actually is a mother bore to the surface, or another lateral, is shown with a seal bore diverter  14  therein. One of ordinary skill in the art will be familiar with a seal bore diverter but not with the profile illustrated thereon in  FIG. 1 . The seal bore diverter  14  includes a diverter face  16  bounded on each longitudinal edge thereof by a recess  18 ,  20 . Each recess as illustrated comprises two surfaces. One of the surfaces is a radial support surface  22  and the other is a hoop support surface  24 . Surfaces  22  and  24  intersect at an acute angle  26  in one embodiment, although it is possible for the intersection to occur at an obtuse angle with consequent reduction in hoop support. In the illustration of  FIGS. 1 and 2 , the angle  26  is about 30 degrees to about 89.9 degrees. 
         [0014]    The surfaces  22  and  24  are dimensioned to approximately the thickness of a hanger assembly  26 , intended to be engaged therewith. This can be appreciated most easily by viewing  FIG. 2 . It is to be understood, however, that it is not required that the dimensions of surfaces  22  and  24  be exactly the same as a surface  30  of hanger assembly  26  but that the dimensions of surfaces  22  and  24  may be somewhat larger or somewhat smaller than surface  30  without significant change in function of the configuration. 
         [0015]    The dimensions of surfaces  22  and  24  are a product of the annular dimension of the sealbore diverter  14  at the cross sections point at which a sectional view is taken. In the  FIG. 2  view, however, it is evident that the dimension of surfaces  22  and  24  provides significant radial support to the hanger assembly  26  relative to what the casing itself might provide simply because of the much greater surface area available on surfaces  22  and  24 . Prior art arrangements are provided support only by the casing  12  and only by happenstance, as a direct teaching for support of the junction in such manner is not to be found in the prior art. 
         [0016]    With the arrangement as illustrated in  FIGS. 1 and 2 , a significant formation collapse resistance is achieved by providing both a much greater surface area for radial support and a hoop support that has not been provided in the past. Crush resistance is significantly increased both because the hanger assembly  26  cannot close at its own window due to surfaces  22  and  24  and because a greater percentage of the hanger assembly  26  is radially supported. The recesses  18  and  20  may be provided by machining, or may be molded in, etc. 
         [0017]    In another embodiment, referring to  FIGS. 3 and 4 , each longitudinal edge  40  of the seal bore diverter  14 , is configured as a flat face  42 , so that hoop stress in the hanger assembly  26  is supported during the application of formation collapse pressure on the hanger assembly  26 . It is to be appreciated that in this embodiment, the window  44  in the hanger assembly  26  is milled differently than is usually the case in the art. Rather, as can be ascertained from a view of  FIG. 4 , window edge surfaces  46  are about ninety degrees from an angle such as that seen in  FIGS. 1 and 2 . The edges  46  are thus well supported by flat faces  42 . This particular embodiment boasts very easy machining to create but as will be appreciated by an attentive reader, the hoop strength improvement of this embodiment is less than that attained in the embodiment of  FIGS. 1 and 2 . 
         [0018]    In yet another alternate embodiment, referring to  FIGS. 5 and 6 , the seal bore diverter  14  is differently configured to have a scooped ramp  50  on both longitudinal sides of the diverter face  16 . In this embodiment, a relatively large surface area of the hanger assembly  26  is supported by the diverter  14  by each of the ramps  50 . This provides added collapse resistance, by simple spreading of the load and is otherwise a simple modification to make to a diverter  14  and thus inexpensive. 
         [0019]    While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.