Method and apparatus for multilateral junction

Abstract

A junction for the intersection of a main borehole and a lateral borehole includes a main tubular having a main window with a ramp aligned with the main window and a lateral tubular adapted to be telescopingly received within the main tubular and having a lateral window. The main tubular and lateral tubular each have an orientation surface. The lateral tubular has a first position with one end partially disposed within the main tubular. The lateral tubular is telescoped into the main tubular with the end of the lateral tubular engaging the ramp which guides the end of the lateral tubular through the main window and into the lateral bore. The orientation surfaces engage to orient the lateral window with the main window and form a common opening between the tubulars.

What is claimed is:  
     
         1 . An apparatus comprising: 
 a tubular borehole casing having an inner surface and a casing aperture in one side thereof;    a tubular having a cylindrical portion with an opening in one side thereof;    an orienting member disposed on said inner casing surface above said casing aperture; and    wherein said tubular has a first position with said casing and said tubular being coaxial and a second position with said tubular engaged with said orienting device, said tubular opening substantially aligned with said casing aperture and said tubular cammed out said casing aperture with one end of said tubular projecting from said casing aperture.    
     
     
         2 . The apparatus of  claim 1  wherein said casing aperture and tubular opening form a common window between said casing and tubular.  
     
     
         3 . The apparatus of  claim 1  wherein said tubular further includes an orienting member disposed on an outer surface of said tubular cylindrical portion above said tubular opening, wherein said tubular orienting member is configured to mate with said casing orienting member.  
     
     
         4 . The apparatus of  claim 1  further comprising a deflector disposed inside said borehole casing below said casing aperture.  
     
     
         5 . The apparatus of  claim 1  wherein said casing aperture forms opposing edges providing a ramp adjacent said casing aperture.  
     
     
         6 . The apparatus of  claim 4  wherein said ramp includes an arcuate surface cut at an angle in said tubular.  
     
     
         7 . A method of deploying a Y junction, the method comprising: 
 pre-milling an aperture in a portion of borehole casing, said aperture forming opposing edges providing a guide surface adjacent said aperture;    inserting one end of a tubular into said borehole casing portion;    further inserting said tubular into said casing portion against said guide surface in said casing portion;    guiding said one end of said tubular along said guide surface through said casing aperture; and    extending said one end of said tubular through said aperture with another end of said tubular remaining in said casing portion to form a Y junction.    
     
     
         8 . A method of deploying a Y junction, the method comprising: 
 inserting one end of a tubular into a borehole casing portion, said casing portion having an aperture in one side thereof and said tubular having an opening in one side thereof;    further inserting said tubular into said casing portion toward said aperture;    camming said one end of said tubular through said aperture;    orienting said tubular and said casing portion using cooperative orientation surfaces on said tubular and said casing portion such that said opening and said aperture align with each other;    extending said one end of said tubular through said aperture with another end of said tubular remaining in said casing portion; and    mating said orientation surfaces to form a Y junction wherein said opening and said aperture form a common window.