A bottom hole assembly (BHA), adapted to be positioned in a casing and to isolate a portion of a wellbore, which includes a packer assembly with a first sealing element extending between first and second portions of the packer assembly. A method of setting a BHA in a casing which includes increasing a BHA pressure to activate an anchor assembly, applying a mechanical force to mechanically deform a first sealing element to thereby establish an initial seal between the first sealing element and an interior surface of the casing, and increasing a pressure in a space between the BHA and the casing and in a cavity within the BHA to increase a differential pressure across the first sealing element and thereby establish a pressure-energized seal between the first sealing element and the interior surface of the casing.