| 摘要 |
An improved drill bit and a method for making the same. A body having an upper end is adapted for connection to a source of rotary motion. A curved surface formed on the lower end of the body includes a plurality of cutting elements embedded therein. A port provides drilling fluid between the curved surface and the bore during drilling. The cutting elements and fluid courses formed on the curved surface define a gap between the surface and the bore during drilling. The gap is formed to provide no more than a substantially linear reduction in drilling fluid pressure with increasing bit radius. In making the bit, a bottomhole pattern and a substantially constant flow area are selected. Dimensions of the lower drill bit surface are calculated to provide the selected flow area over the surface when the bit is in position above the bottomhole pattern. Thereafter, the lower bit surface, including fluid courses thereon, is constructed in accordance with the calculated dimensions and diamonds are embedded therein to support the drill bit surface over the bottomhole pattern by a distance which produces the selected flow area.
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