A method and apparatus for creating multiple branch wells from a parent well is disclosed. According to a first embodiment of the invention a multiple branching sub is provided for placement at a branching node of a well. Such sub includes a branching chamber (32) and a plurality of branching outlet members (34-38). The outlet members, during construction of the branching sub, have previously been distorted into oblong shapes so that all of the branching outlet members fit within an imaginary cylinder which is coaxial with and substantially the same radius as the branching chamber. According to one embodiment, the distorted outlet members are characterized by an outer convex shape. In another embodiment, the distorted outlet members are characterized by an outer concave shape when in a retracted state.; After deployment of the branching sub via a parent casing in the well, a forming tool is lowered to the interior of the sub. The outlet members are extended outwardly by the forming tool and simultaneously formed into substantially round tubes. Next, each outlet member is plugged with cement, after which each branch well is drilled through a respective outlet member. If desired, each branch may be lined with casing and sealed to a branching outlet by means of a casing hanger. A manifold placed in the branching chamber controls the production of each branch well to the parent well. According to a second embodiment of the invention, a pressure resistant branching sub is provided which may be installed in series with a casing string, and the associated equipment used for the installation operation and intervention of a well. The branching sub includes a main pipe and a lateral outlet.