Smith International, Inc.

Angelo Spedale

Charles H Dewey

Shantanu N Swadi

Alan Jackson Marshall

A hammer bit includes a bit body having a bit axis and a bit face, a first circumferential row of cutting elements mounted to the bit face, the first circumferential row located at an outermost radius of the bit face and extending around the bit axis, and a second circumferential row of cutting elements mounted to the bit face, the second circumferential row located radially inwardly adjacent the first circumferential row, wherein each of the cutting elements of the second circumferential row is a semi-round top insert. The ratio of the radial overlap distance to the radial span distance between the cutting profiles of cutting elements of the first and second circumferential rows is between 0.1 and 0.5. The ratio of the radial overlap distance to the radial span distance between the cutting profiles of the first and second circumferential rows is greater than 0.25.

Percussion drilling assembly and hammer bit with gage and outer row reinforcement

A hammer bit for drilling a borehole in earthen formations includes a bit body having a bit axis and a bit face, a plurality of gage cutter elements mounted to the bit face in a circumferential gage row, and a plurality of adjacent to gage cutter elements mounted to the bit face in a circumferential row that is radially adjacent the gage row. The ratio of the radial overlap distance to the radial span distance between radially overlapping gage cutter elements and adjacent to gage cutter elements is greater than 0.25. The ratio of the radial overlap distances to the diameter of the gage cutter element is greater than 0.25. An average cutting area of the gage cutter elements per gage cutter element is less than an average surface area of an entire cutting surface of each of the gage cutter elements.

A hammer bit for drilling a borehole in earthen formations comprises a bit body having a bit axis and a bit face. The bit face includes an inner region extending from the bit axis to about 50% of the bit radius and an outer region extending from the inner region to the outermost radius. In addition, the bit comprises a plurality of gage cutter elements mounted to the bit face in a circumferential gage row in the outer region. Further, the bit comprises a plurality of adjacent to gage cutter elements mounted to the bit face in a circumferential adjacent to gage row in the outer region. The cutting profile of at least one cutter element in each row in the outer region radially overlaps with the cutting profile of at least one other cutter element in a different row in rotated profile view.

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Cypress, TX, United States of America

Angelo Spedale