Earth boring bit for soft to hard formations

摘要

A drill bit having thermally stable PCD cutting elements includes a matrix body element having a plurality of spaced cutting elements supported in a body of matrix material such that a substantial portion of the cutter is above the body matrix and a minor portion is received within the body matrix. The cutters have side surfaces exposed and are so positioned that at least in some of the cutters more surface area of one side face is exposed as compared to the other side faces. The cutter support may include a small pad of matrix material to reduce the loading directly on the PCD. In a preferred form the PCD elements are mounted on pads or blades formed by spaced channels. The hydraulics are straight radial flow and improved hydraulic flow is achieved through the use of waterways which concentrate the fluid flow near the face of the cutters. In one form, improved hydraulics are obtained by having one fluid discharge port for each of the radially disposed fluid channels. Various forms and arrangements are disclosed.