| abstract |
A diamond impregnated drill bit (20) has an adaptive matrix in the ribs (25). The ribs (25) have at least two different areas (31, 32) of metal-matrix composite impregnated with diamonds with different wear resistances. Thus, during boring of formation, the areas (31, 32) will wear at different rates and provide fluid flow spaces across the surface of the ribs. The diamonds may be natural, synthetic or a combination of natural and synthetic diamonds. A method for producing such a drill bit involves the use of a mould for the ribs and either prefabricated blocks of metal-matrix material with different wear resistances or a prefabricated block of metal-matrix material and a mouldable slurry of a metal-matrix material with a different wear resistance. |