Patent ID: 7565928

Claim:
A downhole abrading tool for use in a well, the downhole abrading tool comprising: a tool body having a first end for connection with a rotating component of a drill string, and a cutting end, the cutting end having an abrading matrix containing an abrasive material for rotating engagement with an object within the well, the abrading matrix having a wear-away chamber disposed therein; a drilling fluid passageway through the tool for circulating a drilling fluid into the well; and a removable housing disposed in the drilling fluid passageway, the removable housing having a lower portion, a cavity with at least one taggant contained therein, and a valve disposed in the lower portion, the valve having a closed position when the housing is removed from the drilling fluid passageway and an opened position when the housing is disposed within the drilling fluid passageway, the cavity being in fluid communication with the wear-away chamber through the valve when the valve is in the opened position, so that when excessive wear exposes the wear-away chamber to the drilling fluid in the well, the taggant flows out of the cavity and through the wear-away chamber into the well.