Patent ID: 7520340

Claim:
A method of avoiding the need for a scraper run during hydrocarbon well cement drill out operations, comprising: providing a down hole drilling motor assembly comprising: a rotary scraper having a first end, a second end and spring biased outwardly extending scraper blades, the scraper blades being positioned at a common angle from an axis of the drilling motor with a radial component that is less than an axial component; a drill bit secured to the first end of the rotary scraper; a moineau drilling motor indirectly coupled to the second end of the rotary scraper via a drive shaft and bearing assembly which convert eccentric motion of the moineau drilling motor to concentric motion, the moineau drilling motor rotating the rotary scraper together with the drill bit; attaching the down hole drilling motor assembly to a drill string and inserting the drill string into casing of a hydrocarbon well until further insertion of the drill string is prevented by cement; drilling out the cement with the drill bit by imparting a rotational force via the moineau drilling motor while concurrently scraping cement residue from interior walls of the casing with the rotary scraper.