Patent ID: 7428927

Claim:
A method for drilling a wellbore, comprising: providing a casing string having a known inner diameter and including therein an annular groove having a diameter greater than the casing string inner diameter at a lower distal end of the casing string and a drilling assembly retrievable through the casing string connected at the lower distal end of the casing string; drilling a wellbore using the drilling assembly and casing string; retrieving the drilling assembly through the casing string without removing the casing string from the wellbore; providing a cement float selected to pass through the casing string in sealing engagement therewith, the cement float including a latch to latch into the groove; pumping the cement float through the casing string with the latch biased against the casing string inner diameter until the latch latches into the groove; and completing the wellbore by pumping cement through the casing string and through the cement float.