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 f or engaging the wall of the borehole.