Directional casing-while-drilling

摘要

A directional casing-while-drilling system includes a rotary steerable system disposed within a casing string used as a drill string during casing-while-drilling operations. The casing string of some embodiments may include an upper section and a lower section coupled by a swivel, which may enable the upper section of the casing string to be rotated without substantially rotating the lower section. The rotary steerable system may be disposed at least partially within the lower section of the casing string, and coupled to a drill bit and/or under- reamer. The rotary steerable system may enable radial diversion of the drill bit and/or under- reamer, for example by actuation of one or more components in the rotary steerable system.