Patent Number: 6,308,790

Title: Drag bits with predictable inclination tendencies and behavior

Abstract: A drill bit with dropping tendencies includes an active region, a passive region, a biased mass distribution, an uneven torque generation, and an imbalance force vector directed toward the middle of the active region. Cutting elements in the active region of the drill bit may be more aggressive than those in the passive region through manipulation of, e.g., backrake angle, blade length, cutter sizes, blade angles and bit profile. The imbalance force vector may be achieved by manipulation of bit geometric parameters such as cutter radial position, angular position, longitudinal position, and rake angle.

Inventors: Mensa-Wilmot; Graham (Houston, TX), Simmons; John H. (Missouri City, TX)

Assignee: Smith International, Inc.

International Classification: E21B 7/04 (20060101); E21B 7/06 (20060101); E21B 10/00 (20060101); E21B 10/42 (20060101); E21B 010/46 ()

Expiration Date: 10/30/2018