Smith International, Inc.

Ying Xiang

Sujian Huang

Amardeep Singh

Michael Allen Siracki

James Carl Minikus

George B Witman, Iv

New cutting structures for roller cone drill bits are disclosed. In one aspect, a drill bit includes a bit body, roller cones attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on each of the roller cones, such that axial force on the bit during drilling is substantially balanced between the cones. In another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that the amount of work performed by each cone during drilling is substantially the same as the amount of work performed by each of the other cones. In yet another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that distribution of axial force on the bit is optimized. Additional aspects of the invention are also disclosed.

Method for designing cutting structure for roller cone drill bits

A roller cone drill bit is disclosed which includes a bit body adapted to be coupled to a drill string, a bearing journal depending from the bit body and a single roller cone rotatably attached to the journal. The roller cone has a plurality of inserts disposed thereon. In one aspect, the inserts have an extension length of at least 0.6 inches. A roller cone drill bit is disclosed, including a bit body, a bearing journal depending from the bit body, and a single roller cone rotatably attached to the journal. The roller cone has a plurality of inserts disposed thereon. In another aspect, the inserts are arranged such that at most about 20 percent of the inserts are crossed substantially at centerlines thereof by any single plane which contains the axis of the cone axis and which crosses at least two of the inserts.

Single-cone rock bit having cutting structure adapted to improve hole cleaning, and to reduce tracking and bit balling

An earth-boring bit for drilling a borehole comprises a bit body having a bit axis, at least two rolling cone cutters rotatably mounted on the bit body, a plurality of inner row cutter elements positioned on at least one cone cutter in a first inner row, a plurality of gage-cutting cutter elements positioned in a first fanned-gage row on a first one of the one cutters, and a plurality of gage-cutting cutter elements positioned in a second fanned-gage row on a second one of the one cutters, wherein the gage-cutting cutter elements on the bit define a gage curve and cutter elements in the first fanned-gage row and the second fanned-gage row contact the gage curve at different points. In one embodiment, each cutter element has an extension, and the extensions of the uppermost fanned-gage row cutter element and the first inner row cutter element define a step distance such that the ratio of the step distance to the extension of the first inner row cutter element is greater than 0.5. Alternatively, the first and second fanned-gage rows are positioned to have different oversize angles, positioned such that the ratio of the diameter of the largest fanned-gage row cutter element to the diameter of the first inner row cutter elements is not greater than 0.75, or positioned such that the lowermost fanned-gage row contains more cutter elements than any other fanned-gage row.

Rolling cone bit with elements fanned along the gage curve

New cutting structures for roller cone drill bits. In one aspect, a drill bit includes a bit body, roller cones attached to the bit body and able to rotate with respect to the bit body, and a plurality of cutting elements disposed on each of the roller cones, such that axial force on the bit during drilling is substantially balanced between the cones. In another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that the amount of work performed by each cone during drilling is substantially the same as the amount of work performed by each of the other cones. In yet another aspect, a drill bit includes a plurality of cutting elements disposed on each roller cone such that distribution of axial force on the bit is optimized.

Cutting structure for roller cone drill bits

Cutting structures for roller cone drill bits are disclosed. One aspect is a drill bit which includes a bit body, and a plurality of roller cones attached to the bit body and able to rotate with respect to the bit body. The bit further includes a plurality of cutting elements arranged on each of the roller cones so that cutting elements on adjacent cones intermesh between the adjacent cones. The cutting elements are arranged so that a rotation speed of each cone differs by less than about 7% from the rotation speed of each of the other cones during drilling. Another aspect is a drill bit which includes a bit body, and a plurality of roller cones attached to the bit body and able to rotate with respect to the bit body. The bit also includes a plurality of cutting elements arranged on each of the roller cones so that cutting elements on adjacent cones intermesh between the adjacent cones. In this aspect, at least one of the cutting elements on each cone comprises a gage cutting element, and the gage cutting elements on each cone are arranged so that the scraping distance of the gage cutting elements on each cone is substantially the same as the scraping distance of the gage cutting elements on each of the other cones.

A roller cone drill bit is shown which includes at least one roller cone rotatably mounted on a journal forming a part of a bit body. The at least one cone having cutting elements disposed at selected locations thereon. The at least one roller cone subtends a journal angle of less than about 35 degrees, and has an offset less than about 0.15 inches. In one embodiment, gage row cutting elements on the at least one roller cone define an oversize angle in a range of about &minus;1.5 to &plus;2 degrees.

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The Woodlands, TX, United States of America

Ying Xiang