Multilateral wellbore completion junction with an alternative passage to allow access to the bore below the junction

摘要

A wellbore junction 18 comprises: a main passageway 22 from which a lateral bore 36 branches through a window 20; and a second passageway 60 to allow communication above and below the window 20 when an assembly 26 including a packer 32 is blocking the main passageway 22. A liner string 38 can be passed through the junction 18 into the lateral branch 36 directed by a deflector 28 in the assembly 26. The second passageway 60 maybe collapsible so that it is expanded when the junction 18 is in position. Where there are multiple junctions (figure 15: 36, 174) a third passageway 198 may be used.