Drilling and completion system for multilateral wells

摘要

A wellbore system is provided, the wellbore including a main wellbore extending into an earth formation, a branch wellbore extending from a selected location of the main wellbore into the earth formation and a casing arranged in the main wellbore. A branching device is arranged in the casing and connected to a conduit extending through the casing to a wellbore facility at surface, the branching device having a main bore in fluid communication with the wellbore facility via the conduit, and a branch bore providing fluid communication between the main bore and the branch wellbore via a window opening provided in the casing. A seal is provided between said body and the inner surface of the casing so as to prevent fluid communication between the window opening and the interior of the casing.