This invention is based on a new model describing the drilling process of a drag bit and concerns a method of determining the drilling conditions associated with the drilling of a borehole through subterranean formations, each one corresponding to a particular lithology, the borehole being drilled with...http://www.google.com/patents/US5216917?utm_source=gb-gplus-sharePatent US5216917 - Method of determining the drilling conditions associated with the drilling of a formation with a drag bit
