Importance

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Abstract

A rotary drill bit for use in drilling deep holes in subsurface formations comprises a bit body having a leading face and a gauge region, a plurality of cutting elements mounted at the surface of the leading face of the bit body, a passage in the bit body for supplying drilling fluid to a plurality of openings in the leading face of the bit body, and one or more junk slots in the gauge region of the bit body, whereby drilling fluid emerging from the openings flow over the leading face of the bit body and past the cutting elements thereon, so as to cool and clean the cutting elements before exiting through the junk slot. At least one of the openings is located in an area of the leading face adjacent the gauge region, and is angularly spaced from the nearest associated junk slot, the flow path between the opening and the junk slot being such that, in normal use of the bit, drilling fluid flowing from the opening to that junk slot flows substantially peripherally along an outer peripheral region of the leading face of the bit, adjacent the gauge region, so as to flow past cutting elements in that peripheral region.

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First Claim