Patent ID: 9038752
Filing Date: 2015-05-26
Classification: E21B

Abstract:
1. A downhole tool for boring earth formations, comprising: a body with a cutting face, the body having a central axis around which the body is rotated for boring an earth formation; and a plurality of discrete prefabricated cutters mounted to the cutting face in a row, each of the plurality of discrete prefabricated cutters projecting outwardly from the face and positioned to present a cutting surface for engaging at least a bottom of a bore hole in an earth formation when the body is rotated on its central axis within a bore hole; wherein at least one pair of cutters of the plurality of discrete prefabricated cutters abut each other along complementary side surfaces to form a composite cutting structure and a first of the at least one pair of cutters includes a rearward extending recess deeper at one end of the recess than the other end that receives a second of the at least one pair of cutters, the composite cutting structure presenting a cutting profile that does not expose any portion of the bit body between or behind the at least one pair of cutters to abrasion by the earth formation when the body is rotated during boring of the earth formation.