US 6,711,969 B2 · Methods for designing rotary drill bits exhibiting sequences of substantially continuously variable cutter backrake angles

Abstract

A rotary-type earth-boring drag bit with cutters oriented at varied rake angles and methods for designing such drag bits. Specifically, cutters that are located sequentially adjacent radial distances from a longitudinal axis of the drill bit have cutting faces that are oriented at rake angles that differ from one another. These cutters may be located on the same blade of the drag bit or on different blades of the drag bit. The rake angles at which the cutting faces of these cutters are oriented may be based, at least in part, on the relative radial distances these cutters are spaced from the longitudinal axis of the drag bit, on the vertical positions of these cutters along the longitudinal axis of the drag bit, or in response to actual or simulated evaluations of the use of the drag bit to drill a subterranean formation.

Claims42

Dependent claims

A method for designing a rotary drill bit for drilling a subterranean formation, comprising:

selecting a bit design and desired performance criteria;
selecting at least two sequential cutters for placement on said bit design;
configuring said at least two sequential cutters to be oriented at different rake angles so as to model said bit design with said desired performance criteria;
mathematically simulating drilling of a rock formation with said selected bit design;
and
comparing said mathematical simulation to said desired performance criteria.

3 more elements

Dependencies are inferred from the claim text.

Methods for designing rotary drill bits exhibiting sequences of substantially continuously variable cutter backrake angles

Life of this patent

Methods for designing rotary drill bits exhibiting sequences of substantially continuously variable cutter backrake angles

Life of this patent

Abstract

Claims42