CUTTING ELEMENTS LEACHED TO DIFFERENT DEPTHS LOCATED IN DIFFERENT REGIONS OF AN EARTH-BORING TOOL AND RELATED METHODS Russian patent published in 2018 - IPC E21B10/567 

FIELD: drilling of soil or rock.

SUBSTANCE: group of inventions relates to earth-boring tools and a method of forming thereof. Earth-boring tool comprises a body at a leading end of which there is a crown comprising a cone region located at and around a rotational axis of the body, a nose region adjacent to and surrounding the cone region, shoulder region adjacent to and surrounding the nose region, and a gage region defining a periphery of the body adjacent to and surrounding the shoulder region. Earth-boring tool comprises a first cutting element located in the cone region, secured to the body and comprising a first polycrystalline table, comprising interbonded grains of superhard material, formed by using catalyst material and secured to a first substrate, and a second cutting element located in the nose region, secured to the body and comprising a second polycrystalline table, comprising interbonded grains of superhard material, formed by using a catalytic material and secured to a second substrate. Earth-boring tool also comprises a third cutting element located in the shoulder region, secured to the body and comprising a third polycrystalline table, comprising interbonded grains of superhard material, formed by using catalyst material and secured to a third substrate, and a fourth cutting element located in the gage region, secured to the body and comprising a fourth polycrystalline table, comprising interbonded grains of superhard material, formed by using catalyst material and secured to a fourth substrate. First polycrystalline table is free of catalyst material to a first depth and a second polycrystalline table is free of catalyst material to a second, greater depth, third polycrystalline table is free of catalyst material to a third, even greater depth, and a fourth polycrystalline table is free of catalyst material to a fourth, the greatest depth. Degree of depth increasing from the first depth through the second and third ones to the fourth one corresponds to the Solow growth curve.

EFFECT: technical result is providing cutting elements of an earth-boring tool with close service life.

10 cl, 7 dwg