Drill Bit and Cutting Inserts For Hard/Abrasive Formations
First Claim
1. A rolling cone drill bit for drilling a borehole in earthen formations, the bit comprising:
- a bit body having a bit axis;
at least one rolling cone cutter mounted on the bit body for rotation about a cone axis and having a first surface for cutting the borehole bottom and second surface for cutting the borehole sidewall;
a plurality of cutter elements secured to the cone cutter and extending from the first surface and positioned in a first circumferential row;
at least one of the cutter elements comprising a cutter element axis, a base portion having a diameter, and a cutting portion extending from the base portion to a point furthermost from the base portion defining an extension height;
wherein the ratio of the cross-sectional area of the cutter element defined by a plane perpendicular to the cutter element axis at a point equal to ninety-four percent of the extension height to the cross-sectional area of the cutter element base defined by a plane perpendicular to the cutter element axis is greater than 0.2; and
wherein the ratio of the extension height to the base diameter is not greater than 0.75.
1 Assignment
0 Petitions
Accused Products
Abstract
A rolling cone drill bit comprises a plurality of bottomhole cutter elements positioned in a first circumferential row, wherein at least one of the cutter elements comprises a cutting portion extending from a base portion to a point furthermost from the base portion, defining an extension height. The ratio of the cross-sectional area of the cutter element at a point equal to ninety-four percent of the extension height to the cross-sectional area of the cutter element base is greater than 0.2. Moreover, the ratio of the extension height to the base diameter is not greater than 0.75.
124 Citations
54 Claims
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1. A rolling cone drill bit for drilling a borehole in earthen formations, the bit comprising:
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a bit body having a bit axis;
at least one rolling cone cutter mounted on the bit body for rotation about a cone axis and having a first surface for cutting the borehole bottom and second surface for cutting the borehole sidewall;
a plurality of cutter elements secured to the cone cutter and extending from the first surface and positioned in a first circumferential row;
at least one of the cutter elements comprising a cutter element axis, a base portion having a diameter, and a cutting portion extending from the base portion to a point furthermost from the base portion defining an extension height;
wherein the ratio of the cross-sectional area of the cutter element defined by a plane perpendicular to the cutter element axis at a point equal to ninety-four percent of the extension height to the cross-sectional area of the cutter element base defined by a plane perpendicular to the cutter element axis is greater than 0.2; and
wherein the ratio of the extension height to the base diameter is not greater than 0.75. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A rolling cone drill bit for drilling through earthen formations to form a borehole with a hole bottom and a sidewall, the drill bit comprising:
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at least one rolling cone cutter rotatably mounted on a bit body, the rolling cone cutter including a first surface generally facing the borehole bottom and a second surface generally facing the sidewall of the borehole;
at least one cutter element mounted in the rolling cone cutter and secured in a position to cut against the borehole bottom;
the at least one cutter element including a base portion and a cutting portion extending from the base portion to a cutting tip, the cutting portion tapering from the base portion to the cutting tip and defining an extension height;
wherein the at least one cutter element has a tip-to-base volume ratio of at least 0.17. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34)
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35. A rolling cone drill bit for drilling through earthen formations to form a borehole having a hole bottom and a hole sidewall, the drill bit comprising:
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at least one rolling cone cutter rotatably mounted on a bit body for rotation about a cone axis;
a plurality of inner row cutter elements mounted in the cone cutter in a first circumferential row, the inner row cutter having a generally conical cutting portion extending from a cylindrical base to a cutting tip and defining an extension height, wherein the extension height is not greater than 0.75;
a plurality of gage row cutter elements mounted in the cone cutter in a second circumferential row, the gage row cutter elements having a cutting portion extending from a generally cylindrical base to a cutting tip and defining an extension height, wherein the extension height of the gage row cutter elements are not greater than 0.5; and
wherein the plurality of inner row cutter elements and a plurality of gage row cutter elements each include a tip-to-base volume ratio of at least 0.17. - View Dependent Claims (36, 37, 38, 39, 40, 41, 42, 43)
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44. The method of designing a rolling cone drill bit for forming a borehole, the method comprising:
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selecting a rolling cone cutter;
selecting a location on the rolling cone cutter for mounting a cutting insert having a base portion retained in the cone cutter and a cutting portion extending therefrom to cut a portion of the borehole bottom;
selecting the diameter for the base portion;
selecting the extension height for the cutting portion;
selecting the geometry of the cutting portion such that the cutting insert has a tip volume of at least 0.0010 in3. - View Dependent Claims (45, 46, 47)
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48. A rolling cone drill bit for drilling through earthen formations to form a borehole with a hole bottom and a sidewall, the drill bit comprising:
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at least one rolling cone cutter rotatably mounted on a bit body, the rolling cone cutter including a first surface generally facing the borehole bottom and a second surface generally facing the sidewall of the borehole;
at least one cutter element mounted in the rolling cone cutter and secured in a position to cut against the borehole bottom;
the at least one cutter element including a cutter element axis, a base portion and a cutting portion extending from the base portion to a point furthermost from the base portion defining an extension height;
wherein the at least one cutter element has a tip-to-base volume ratio of at least 0.30. - View Dependent Claims (49, 50, 51, 52, 53, 54)
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Specification