The operational theory and experimental study of scraping-wheel diamond bit

The Scraping-wheel Diamond Bit is a new bit technology being put forward to solve the problems such as seriously uneven wear, thermal wear on the cutters of traditional diamond bits, especially PDC bits. The essential feature of this new technology is that the bit body is configured with rotational scraping-wheels with large angular deflection meanwhile the wheels are fixed with PDC compacts or other diamond cutters. When drilling in the formation, the scraping-wheel is driven to rotate slowly so that cutters thereon scrape the bottomhole rock successively rather than continuously. In this study, basic theory of geometry and kinematics of the Scraping-wheel Diamond Bit has been established, and variation law of wheel/bit speed ratio, tracks of cutters and main structure of the novel bit have been researched. Besides, an indoor simulated rock-breaking experiment for the Scraping-wheel Diamond Bit has been conducted, in which the influencing rule of the structure type and the structural parameters on cutters during the successive cutting process has been researched. Thus, significant experiment results, especially in the aspects of the variation law of wheel/bit speed ratio and the moving tracks of cutters, are achieved through this experiment, which not only proved the theory of geometry and kinematics of the novel bit, but also provided strong support for the rationality and feasibility of this new technology.