A drill bit includes a bit body having a face on which two different types
of cutting elements are disposed, the first type being cutting elements
for drilling at least one subterranean formation and the second type
being cutting elements for drilling through a casing bit disposed at an
end of a casing or liner string and cementing equipment or other
components. The second type of cutting elements exhibits a relatively
greater exposure than the first type of cutting elements, so as to engage
the interior of the casing bit and, if present, cementing equipment
components and cement to drill therethrough, after which the second type
of cutting elements quickly wears upon engagement with the subterranean
formation material exterior to the casing bit, and the first type of
cutting elements continues to drill the subterranean formation.