The Auto Fill Cement Float Shoe permits the casing to fill automatically while being into the hole. The valve is in the open position while running in allowing maximum filling of the casing as it is lowered into the well bore. This is especially effective on liner jobs and sensitive whole conditions. The circulation may be established at any time during or after casing is run. The flapper type back pressure valve does not become operative until the drop ball is dropped or pumped down. From this point on like Differential Fill-up Shoe, this model Auto Fill Cement Float Shoe acts as conventional Floating Equipment. All Auto fill Cement Float Shoes are PDC drillable.