Description of Casing Shoe
The device consists of a metal collar fitted at the base of the casing string, and held in place by the casing hanger at the top. Some designs are snub-nosed, with the angled edges allowing the casing shoe to nudge into the wellbore and stay evenly positioned. Others may have cutting teeth. These can be necessary if the walls of a wellbore are bulging inward and materials are clogging the way; the casing shoe can cut through the to allow the pipe to pass.
Such equipment makes it possible to lower a casing string safely past potential obstructions, ledges, and various obstacles inside the wellbore. Technicians still need to move carefully, monitoring the casing string for signs of fatigue and stress that might potentially cause a problem. This process can be painstaking and very expensive, because technicians want to make sure it is performed correctly. They also need to secure the casing string to confirm that it won’t drop unexpectedly, and so they can maintain control over it at all times.