Patent ID: 6315063
Filing Date: 2001-11-13
Classification: E21B

Abstract:
An improved fluid pressure powered reciprocating drilling motor comprising:a housing for applying a down force;a mandrel-bit mounted for sealed extension with the housing;means for supplying a pressure fluid to the housing;an automatic fluid valve means having an opening and closing cycle frequency;a pressure fluid responsive mandrel for providing resistance to the housing down force;a variable volume fluid chamber defined in part by the housing, the mandrel-bit and the automatic fluid valve means for varying fluid pressure and volume in the chamber;a fluid control means to limit and meter pressure and volume to the automatic fluid valve means and thereby determine valve means cycle frequency and impulsive pressure forces in the chamber; and,impact receiving surfaces on the housing and the mandrel-bit, wherein periodic pressure fluid force in the chamber becomes greater than the housing down force and/or greater than the mandrel-bit resistance and thereby alternately forces the impact receiving surfaces of the housing and the impact receiving surfaces of the mandrel-bit apart some distance and then allows them to come together in collision at the valve means cycle frequency thereby producing percussive blows and motor reciprocating vibratory action for improved bit drilling performance.