Patent ID: 6892830

Claim:
A rotary steerable drilling tool, comprising: (a) a mandrel; (b) a housing mounted on the mandrel for rotation in relation to the mandrel; and (c) an adjustable offset mechanism on the housing, the adjustable offset mechanism being surface adjustable to move the rotary steerable drilling tool to and from a straight ahead drilling position and an offset drilling position: (d) a first sensor on the mandrel that is sensitive to a rotary orientation of the housing, the first sensor providing a signal indicative of the rotary orientation of the housing on the mandrel, for use in controlling the rotary steerable drilling tool; (e) a second sensor on the mandrel, the second sensor being longitudinally offset from the first sensor; (f) the first sensor being sensitive to the rotary orientation of the housing in relation to the mandrel when the rotary steerable drilling tool is an on-bottom drilling position; and (g) the second sensor being sensitive to the rotary orientation of the housing in relation to the mandrel when the rotary steerable drilling tool is in a pulled back position.