Patent ID: 8985243
Filing Date: 2015-03-24
Classification: E21B

Abstract:
1. 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°.