Patent ID: 7766101

Claim:
A casing drilling system, comprising: a casing having a drill bit at one end, the drill bit capable of drilling subsurface Earth formations and formed from a material susceptible to removal from the casing by at least one of drilling with another well drilling bit and chemical exposure, wherein the chemical exposure is substantially harmless to the casing; at least one centralizer affixed to an interior of the casing, the at least one centralizer including a receptacle therein for engaging a measurement while drilling tool, the at least one centralizer formed from a material susceptible to removal from the casing by at least one of drilling with another well drilling bit and chemical exposure, wherein the chemical exposure is substantially harmless to the casing; and a measurement while drilling tool configured to move along the interior of the casing and to engage with the at least one centralizer, the measurement while drilling tool including at least one device to measure a drilling parameter or a formation parameter, the measurement while drilling tool including a latch at an upper end thereof for engagement with a retrieval tool moved through the interior of the casing, wherein the at least one centralizer comprises at least one passage for flow of drilling fluid between an exterior of the measurement while drilling tool and the interior of the casing.