Study on rock breaking efficiency of special shaped cutters

Abstract

Abstract The optimization of cutter shape has become one of the main innovation direction of PDC bit technology. At present, both domestic and foreign bit manufacturers have put forward various special shaped cutters to improve rock breaking efficiency. However, there are relatively few researches which focus on the rock breaking efficiency of special-shaped cutters. Therefore, three kinds of typical cutters (flat cutter, convex cutter and concave cutter) are selected as the study object in this paper. Based on the single cutter test, the relationship of axial cutting force, cutting area and cutting specific energy under different working conditions will be provided. The experimental results show that the axial cutting force and specific energy of concave cutter and convex cutter are lower than that of flat cutter in most test cases. The results are almost the same for both Vosges sandstone and Marcellus shale cases. In other words, the tested concave cutters are easier to intrude into rock and obtain higher rock brea king efficiency under the same cutting conditions, when compared with flat cutter and convex cutter. The experimental method provides a technica l reference for studying the rock breaking efficiency of three-dimensional cutters with different shapes.