1) Drilling technology 
In oil drilling and borehole mining, a casing shoe or guide shoe is a bull-nose shaped device which is attached to the bottom of the casing string. A casing hanger, which allows the casing to be suspended from the wellhead, is attached to the top of the casing. ...
The Casing Shoe is a reinforced section of casing run into a well at the lower end of a string, this is used to protect against bucking or deformation.
see guide shoe