Hybrid pdc bit

Abstract

A bladeless polycrystalline diamond compact (PDC) drill bit includes a head having a plurality of knots protruding from a drilling face of the head. Each of the plurality of knots includes a single cutter. Each of the cutters is arranged about a central axis of the head such that each cutter has a unique radial position and angular position relative to the central axis. The head defines at least one fluid port extending through the drilling surface.

Description

BACKGROUND OF THE INVENTION

[0001] Conventional PDC drill bits include a number of blades arranged about a drilling face of the bit, with each blade supporting a number of cutting elements. Due to the arrangement of the blades and cutting elements, these bits suffer from several problems. Notably, the concentrations of cutters on each blade (at a same or similar angular position) cause high and irregular torque responses. This is especially true for cutters positioned near an outer periphery of the bit, since the torque generated on any cutter and / or blade is a function of the radial distance of the cutter from the center of the bit, with most outward cutters generating greater torque values. The high and irregular torque responses may lead to bit whirling, as well as result in especially high forces being applied to a small subset of the cutting elements on a particular blade that may cause excessive wear or other damage to one or more of the cutting elements and / or blades. Additiona...

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