Drag bit with gauge pads of varying aggressiveness

A rotary drag bit 10, including a gauge design which facilitates steerability while preventing lateral displacement of the bit and attendant ledging of the borehole wall, and reams and conditions the borehole wall as the bit advances through the formation. The bit includes an elongated gauge section comprised of a plurality of circumferentially spaced gauge pads 36, each including mutually-longitudinally displaced gauge pad segments of varying lateral aggressiveness, or tendency to cut formation material under application of load. A leading gauge pad segment 38 extending from and closest to the bit face is somewhat aggressive, being provided with conventional PDC cutting elements 28, while an intermediate gauge pad segment 40 is devoid of cutters and may be characterized as a "slick" gauge segment, acting as a bearing surface and limiting lateral displacement of the bit under pure side loads, and a trailing, tapered gauge pad segment 42, is somewhat aggressive, being provided with cutting elements (fig 1A, 52a-c) to ream and condition the borehole wall.