Impact resistant PDC drill bit
AssigneeSmith International, Inc.
InventorGraham Mensa-Wilmot
Life of this patent
Estimating the term…
Abstract
A drill bit includes at least two different sets of cutting elements, each being the primary cutting set corresponding to a different formation. Upon encountering a significant change in formation characteristics, the first set of cutting elements may be sacrificed so that the second set of cutting elements becomes exposed, preventing the need to replace the drill bit immediately. The sets of cutting elements differ from one another, with each adapted to cut a different formation. The differences may include material toughness (impact resistance), bevel size, abrasion resistance, or backrake angle. Additional sets of cutting elements may be added to correspond to other formations or to otherwise improve performance.
Claims49
A drill bit, comprising:
- a drill bit body having a face end, a connection end, and a longitudinal axis;
- at least one of a first type of cutting element mounted to said face end of said drill bit body, said first type of cutting element having a first grain size, a first backrake, a first bevel size;
- at least one of a second type of cutting element mounted to said face end of said drill bit body at substantially a same radial distance from said longitudinal axis as said first type of cutting element, said second type of cutting element having a second grain size, a second backrake, a second bevel size;
- wherein at least two of the following are true:
- said second type of cutting element is made from a material having a different impact resistance than is said first type of cutting element;
- said bevel size for said second type of cutting element is different than for said first type of cutting element;
- and
- said backrake angle for said second type of cutting element is different than for said first type of cutting element.
A method for cutting a borehole through a plurality of formations, comprising:
- cutting through a first formation using primarily a first set of cutting elements;
- and
- cutting through said second formation using primarily a second set of cutting elements.
A drill bit, comprising:
- a drill bit body having a face end, a connection end, and a longitudinal axis;
- at least one of a first type of cutting element mounted to said face end of said drill bit body, said first type of cutting element having a first first backrake, a first bevel size, and being made from a first material;
- at least one of a second type of cutting element mounted to said face end of said drill bit body at substantially a same radial distance from said longitudinal axis as said first type of cutting element, said second type of cutting element having a backrake, a second bevel size, and being made from a second material;
- wherein at least two of the following are true:
- said second type of cutting element being made from a material having a different abrasion resistance than is said first type of cutting element;
- said bevel size for said second type of cutting element is different than for said first type of cutting element;
- and
- said backrake angle for said second type of cutting element is different than for said first type of cutting element.
A drill bit, comprising:
- a drill bit body having a face end, a connection end, and a longitudinal axis;
- at least one of a first type of cutting element mounted to said face end of said drill bit body, said first type of cutting element having a first bevel size;
- at least one of a second type of cutting element mounted to said face end of said drill bit body at substantially a same radial distance from said longitudinal axis as said first type of cutting element, said second type of cutting element having a second bevel size;
- wherein said bevel size for said second type of cutting element is different than for said first type of cutting element.
Dependencies are inferred from the claim text.