brocas e ferramentas de perfuração para perfuração subterrânea, métodos de fabricação de tais brocas e ferramentas de perfuração e métodos de perfuração fora de centro

摘要

A method of off-center drilling comprises positioning a drill bit (10) including a bit body, a longitudinal axis (29) and at least one blade (24) extending at least partially over a nose region of the bit body, a shoulder region of the bit body and a gage region of the bit body within a bore hole in a formation; rotating the bit body along an axis of rotation (76) that is offset from the longitudinal axis (29) of the drill bit; and positioning a leading portion of a blade face of the at least one blade into direct rubbing contact with the formation while preventing a trailing portion of the blade face from coming into direct rubbing contact with the formation.