Steerable underreaming bottom hole assembly and method

摘要

A steerable bottom hole assembly may be used for drilling both a curved section and straight section of the borehole, with the bottom hole assembly including a reamer beneath the downhole motor 12. The bottom hole assembly includes a bit 30 having a bit face defining a bit diameter, and a gauge section 32 having a substantially uniform diameter cylindrical surface approximating the bit diameter and having an axially length of at least 75% of the bit diameter. The motor is preferably run slick without stabilizers for engaging the wall of the borehole.