Research On Rock Breaking Characteristics Of A New Type Of PDC Bit With Modular Teeth

Aiming at the characteristics of the rapid decrease of specific pressure with the increase of wear in the process of rock breaking of the existing drill bit, a new type of ratio pressure-controlled modular PDC(Polycrystalline Diamond Compact) drill bit (called modular drill bit) is proposed. The biggest difference between the modular drill bit and PDC drill bit is the cutting unit, and using a new modular cutter in PDC bit can improve the rate of penetration (ROP) dramatically. By comparing with the modular cutter and conventional PDC cutter, the four aspects of the cutter structure, mechanical model, cutter wear and field trials are studied, and the difference between the modular drill and conventional drill is compared.Modular cutter includes the module substrate and module unit, the modular unit is the main cutting unit and bears the most loads. Layout method of the module and module unit is called the module cutting unit program. Therefore different module cutting unit programs must have different cutting edge lengths. In this paper, the mechanical model of a module drill cutter are built in the rock-breaking process, and then the relationships between the cutting depth, effective cutting area and unit pressure are analyzed, including the factors that affect PDC bit ROP and the effect of cutter wear on rock breaking. Finally, the rates of penetration of the modular drill and conventional PDC drill bit are analyzed in theory, and the modular drill rock-breaking features are summarized.First of all, the numerical example is analyzed theoretically, and then the rock test and single cutter test are conducted. Finally, according to the field test results of modular cutter PDC drill bit with conventional drill bit, the rates of penetration of the two drill bits are compared and analyzed.In this paper, the theoretical analysis and field test are combined and the rock-breaking properties of modular drills are studied systematically. Its findings provide some groundwork for further research in the structure and life of modular drill.