Hydraulic power-driven casing reamer shoes are used in the bottom of the casing pipe assembly to ream instable obstructed parts of the borehole and if needed to further drill the wellbore while landing the casing. While lowering the casing into the hole, the casing pipes may not be rotated as the rotation of the reaming head of the shoe (shoe bit) is secured by fluid that is pumped through the shoe.
After the casing reached the target depth, it is cemented through the reamer shoe according to the standard procedure. Following this, the reamer shoe can be drilled thru with a standard BHA including a PDC or tricone bit, and the next section of the wellbore can be drilled with the same BHA without tripping it out for changing the bit.