A well system includes a deflector arranged within a main bore of a wellbore and defining a first channel that exhibits a predetermined diameter and communicates with a lower portion of the main bore, and a second channel that communicates with a lateral bore. A bullnose assembly has a bullnose tip, a piston movably arranged within the bullnose tip, and a wedge member operatively coupled to the piston such that movement of the piston correspondingly moves the wedge member. A coil is arranged about the bullnose tip and in contact with the wedge member, and the piston is actuatable to move the wedge member and thereby radially expand the coil. When the coil is radially expanded, the diameter of the bullnose tip exceeds the predetermined diameter.