The casing shoe is threaded to the end of the casing string for penetration through overburden. It assists in seating the drill casing into the bedrock, providing a tight seal for the drilling fluids to return to the surface. It is also used to ream the casing downward when advancing a casing string in an existing hole with the rod string still in place.
The casing shoe inside diameter is free of diamonds and is designed to be flush with the inside diameter of the casing, allowing free passage of the core barrel through the shoe. Casing shoes are available in standard and oversize diameters.
