Exploration / Tooling / Bits
Casing Shoes & Casing Bits
Casing & Rod Shoes
Casing and rod shoes are threaded to the end of the outer drill string for penetration through overburden. It assists in seating the outer drill string into the bedrock, providing a tight seal for the drilling fluids to return to the surface. A casing shoe can be 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 ID is flush with casing which allows free passage of the core barrel through the shoe.
Casing Bits
These are less commonly used and differ from casing shoes in that the ID of the casing bit is smaller. It does not permit the passage of the core barrel due to the overlap of dimensions.
Casing bits are used when deep or difficult overburden is encountered or to ream over rod strings when stuck in the hole.
