Patent ID: 7464770

Claim:
A downhole steering tool configured to operate in a borehole, the steering tool comprising: a plurality of blades deployed on a housing, the blades disposed to extend radially outward from the housing and engage a wall of the borehole, said engagement of the blades with the borehole wall operative to eccenter the housing in the borehole; a hydraulic module including (i) a plurality of valves, (ii) a fluid chamber disposed to provide high pressure fluid to each of the plurality of blades, and (iii) at least one pressure sensor disposed to measure a pressure in the fluid chamber, the high pressure fluid operative to extend the blades; a controller disposed to (i) receive pressure measurements from the sensor and (ii) regulate the pressure in the fluid chamber via short circuiting the high pressure fluid with low pressure fluid through one of the blades, said short circuiting accomplished via opening at least one of the valves in response to said pressure measurements.