Abstract: The disclosure discloses a percussion and cutting composite drilling tool, which relates to the field of drilling equipment and is mainly used to solve the problems of low working efficiency and high wear rate of drill bit existed in breaking rocks only by cutting effect. The main structure comprises a PDC drill bit and a percussion drill bit, which is characterized by a percussion structure directly connected to the percussion drill bit. The disclosure provides a percussion and cutting composite drilling tool, which is suitable for strata under different geological conditions and has higher construction efficiency and lower bit wear.

Abstract: A roller bit for rock breaking by rotary cutting comprises: a bit body (1), a roller (2) and cutting teeth (3). An included angle ? between a roller journal plane of the bit body and the roller on a bit axis has a range of 0°<?<90°, a journal offset S has a range of ?D/2<S<D/2, wherein D represents a diameter of the bit. Inner row of teeth rings on the bit cuts a center of a borehole bottom, and each row of teeth ring is capable of scraping a borehole wall, and thus the bit has good effects of gauge protection and sidetracking.

Abstract: A modular cutting-teeth bit having controllable specific pressure for drilling includes: a module (1), a modular unit (2), a bit body (3), conventional cutting teeth (4) and a nozzle (5). According to mechanical performance of the rocks in the strata drilled and requirements of drilling well, a combination of shapes, sizes and numbers of the module and the modular unit is optimized; effective abrasion edge length of the cutting unit on a certain portion of the bit is controlled; and a constant specific pressure of the cutting unit of the bit during the drilling process is maintained.

Abstract: A modular cutting-teeth drill bit with controllable drilling specific pressure comprises a module (1), a modular unit (2), a bit body (3), conventional cutting teeth (4) and a nozzle (5). According to mechanical performance of the rocks in the strata drilled and requirements of drilling well, a combination of shapes, sizes and numbers of the module and the modular unit is optimized; effective abrasion edge length of the cutting element on a certain portion of the bit is controlled; and a constant specific pressure of the cutting element of the bit during the drilling process is maintained. The modular cutting-teeth bit substantially improves the effective abrasion volume of the cutting element, and improves the effective utilization rate of the cutting element.