US 8,985,243 B2 · Composite drill bit

Abstract

A composite drill bit with a bit body configured at its upper extend for connection into a drillstring, comprising: a bit body (1) with at least one bit leg (3), at least one scraping-wheel (2) set with a cutter-row (4), and a set of cutters fixed thereon. The scraping-wheel (2) is mounted for rotation on the corresponding bit leg (3) with a large angular deflection α in the range of 20°≦|α|≦90°. The cutters on the scraping-wheel break rock by means of successive scraping, forming a cross-cutting area on the bottomhole accompanied by the cutters on the fixed cutting unit, thus achieving high rock-breaking efficiency, even wear, high cooling performance, and a longer service life for the cutters, bearings and the drill bit.

Claims19

Dependent claims

A composite drill bit, comprising:

a bit body with at least one bit leg,
at least one fixed blade having a plurality of cutters disposed thereon;
and
at least one scraping-wheel rotatably mounted on the bit leg,
wherein the scraping-wheel comprises an outer-row of cutters disposed along a periphery of the scraping-wheel,
wherein the outer-row of cutters comprises one or more polycrystalline diamond compact cutters,
wherein an angle δ is between a rotational axis of the scraping-wheel and an axis along a longitudinal direction of the polycrystalline diamond compact cutter in a direction pointing outwardly from the cutting surface of the polycrystalline diamond compact cutter, wherein the angle δ is an acute angle,
wherein an angular deflection α of the scraping wheel is in a range of 20°≦|α|≦90°.

5 more elements

Dependencies are inferred from the claim text.

Composite drill bit

Life of this patent

Composite drill bit

Life of this patent

Abstract

Claims19