Junction assembly, system and method for providing a downhole junction

Abstract

The invention is directed at a junction assembly adapted for insertion in a borehole and a system and a method for providing a junction in a borehole. The junction assembly is comprised of a primary conduit and a lateral conduit. The primary conduit has an upper end, a lower end, and defines a primary conduit bore extending through the primary conduit from the upper end to the lower end. The lateral conduit is connected with the primary conduit at a conduit junction located between the upper end of the primary conduit and the lower end of the primary conduit, wherein the lateral conduit extends within the primary conduit bore from the conduit junction towards the upper end of the primary conduit.

1 . A junction device for providing a lateral junction in a borehole, comprising a primary conduit having an upper end portion and a lower end portion, each of which is arranged for attachment with one or more casing members to form a borehole casing string, the primary conduit forming a primary conduit bore, a lateral conduit having a lateral conduit bore, the lateral conduit being anchored to the primary conduit so as to be immovable relative thereto, the primary conduit having a first peripheral region encircling a junction opening formed therein, the lateral conduit having a second peripheral region encircling the lateral conduit bore, the second peripheral region being sealably welded to the first peripheral region so as to form a lateral conduit path which is isolated from the primary bore.  
   
   
       2 . A device as defined in  claim 1 , wherein the first peripheral region includes a first peripheral surface and the second peripheral region includes an upstanding flange which extends at least partway along the junction opening, the upstanding flange including a second peripheral surface, the second peripheral surface lying immediately adjacent the first peripheral surface.  
   
   
       3 . A device as defined in  claim 2 , further including a continuous weld seam joining the first and second peripheral regions adjacent the first and second peripheral surfaces.  
   
   
       4 . A device as defined in  claim 3 , further comprising attachment means for attaching the lateral conduit to the primary conduit in advance of the junction opening.  
   
   
       5 . A device as defined in  claim 3 , the lateral conduit having an outer surface exposed to the primary conduit bore, the primary conduit having an inner surface exposed to the primary conduit bore, attachment means for attaching the lateral conduit to the primary conduit with the outer and inner faces immediately adjacent one another.  
   
   
       6 . A device as defined in  claim 5 , wherein the attachment means includes one or more weld joints between the adjacent lateral and primary conduits.  
   
   
       7 . A device as defined in  claim 6 , wherein the primary conduit has an outer surface to communicate with the borehole and the second peripheral region terminates at or is substantially flush with the outer surface within the first peripheral region.  
   
   
       8 . A device as defined in  claim 7 , wherein the primary conduit is operable to maintain a first fluid pressure ranging from about 0 to about 10 MPA while the lateral conduit is operable to maintain a second fluid pressure ranging from about 30 to 60 MPA.  
   
   
       9 . A device as defined in  claim 1 , wherein the primary conduit includes a primary longitudinal axis and the first section of the lateral conduit includes a first longitudinal axis which is substantially parallel with but offset from the primary longitudinal axis.  
   
   
       10 . A device as defined in  claim 9 , wherein the second section of the lateral conduit has a second longitudinal axis which is at an angle less than ninety degrees less relative to the primary longitudinal axis.  
   
   
       11 . A junction device for providing a lateral junction in a borehole, comprising primary conduit means having an upper end portion and a lower end portion, first attachment means for attaching the upper and lower end portions to one or more casing members to form a borehole casing string, the primary conduit means forming a primary conduit bore, the lateral conduit means having a lateral conduit bore, the lateral conduit means being anchored to the primary conduit means so as to be immovable relative thereto, the primary conduit means having a first peripheral region circumscribing a junction opening formed therein, the lateral conduit means having a second peripheral region circumscribing the lateral conduit bore, second attachment means for sealingly attaching the second peripheral region to the first peripheral region so as to form a lateral conduit path which is isolated from the primary bore.  
   
   
       12 . A device as defined in  claim 11 , wherein the first peripheral region includes a first peripheral surface and the second peripheral region includes an upstanding flange means, the upstanding flange means including a second peripheral surface, the second peripheral surface lying immediately adjacent the first peripheral surface.  
   
   
       13 . A device as defined in  claim 12 , wherein the second attachment means includes a continuous weld seam joining the first and second peripheral regions adjacent the first and second peripheral surfaces.  
   
   
       14 . A device as defined in  claim 13 , further comprising third attachment means for attaching the lateral conduit means to the primary conduit means in advance of the junction opening.  
   
   
       15 . A device as defined in  claim 14 , the lateral conduit having an outer surface exposed to the primary conduit bore, the primary conduit having an inner surface exposed to the primary conduit bore, the third attachment means arranged for attaching the lateral conduit to the primary conduit with the outer and inner faces immediately adjacent one another.  
   
   
       16 . A device as defined in  claim 15 , wherein the third attachment means includes one or more weld joints between the adjacent lateral and primary conduits.  
   
   
       17 . A device as defined in  claim 16 , wherein the primary conduit means has an outer surface to communicate with the borehole and the second peripheral region terminates at or is substantially flush with the outer surface within the first peripheral region.  
   
   
       18 . A device as defined in  claim 17 , wherein the primary conduit is operable to maintain a first fluid pressure ranging from about 0 to about 10 MPA while the lateral conduit is operable to maintain a second fluid pressure ranging from about 30 to 60 MPA.  
   
   
       19 . A device as defined in  claim 11 , the lateral conduit means having a first section which is aligned with the primary conduit means, and a second section adjacent the junction opening which is oriented at a build angle of less than ninety degrees relative to the primary conduit means.  
   
   
       20 . A device as defined in  claim 19 , wherein the build angle ranges from about 5 to about 20 degrees.  
   
   
       21 . A device as defined in  claim 20 , wherein the build angle is about 15 degrees.  
   
   
       22 . A device as defined in  claim 11 , wherein the primary conduit means includes primary longitudinal axis and the first section of the lateral conduit has a first longitudinal axis which is substantially parallel with but offset from primary longitudinal axis.  
   
   
       23 . A device as defined in  claim 22 , wherein the second section of the lateral conduit has a second longitudinal axis which is at an angle less than ninety degrees less relative to the primary longitudinal axis.  
   
   
       24 . A method for providing a junction in a borehole, the method comprising the following steps: 
 (a) positioning a pipe string and a junction assembly connected with the pipe string at a desired depth in the borehole;    (b) inserting an orienting device in the pipe string such that the orienting device selectively engages the junction assembly;    (c) obtaining an indication of an orientation of the orienting device;    (d) rotating the pipe string and the junction assembly in order to obtain a desired orientation of the junction assembly;    (e) maintaining the desired orientation of the junction assembly in the borehole while introducing a bonding agent into the borehole through the orienting device; and    (f) removing the orienting device from the pipe string.    
   
   
       25 . The method as claimed in  claim 24 , further comprising the following steps: 
 (g) inserting a guide in the pipe string with a running and retrieval tool such that the guide selectively engages the junction assembly; and    (h) inserting an object in the pipe string such that the object is guided into the lateral conduit by the guide.    
   
   
       26 . The method as claimed in  claim 25 , wherein the object is comprised of a drilling tool for drilling a lateral borehole.  
   
   
       27 . The method as claimed in  claim 25 , wherein the object is comprised of a liner for lining a lateral borehole.  
   
   
       28 . The method as claimed in  claim 25 , further comprising the step of removing the guide from the pipe string with the running and retrieval tool.  
   
   
       29 . The method as claimed in  claim 28 , wherein the step of removing the guide from the pipe string is comprised of shearing a shear mechanism associated with the junction assembly.