Polycrystalline Diamond Compact (PDC) bit has been widely used in natural gas/oil drilling industry for its advantages such as no rotating parts, highly rate of penetration (ROP) and durability. In recent decades, the comprehensive property of PDC bit has been improved rapidly due to the scientists’ efforts. Hydraulic design of PDC bit is very important because the retention of the cuttings may dramatically decrease ROP. Most current researches focus on how blade profile and nozzle parameters affect hydraulic performance of PDC bit, but, the understanding of gauge geometrical parameters (mainly refer to gauge width, gauge length and gauge spiral angle) effects on hydraulic performance of PDC bit is still incomplete.

In this paper, a simulation method and an optimization method were applied to find the best gauge parameter for 8.5 inch PDC bit. In the proposed approach, the approximate range of above three parameters were confirmed first based on previous studies. Then, the central composite design (CCD) was used to design numerical simulation scheme and the discrete particle modeling (DPM) was used to track the cuttings and the velocity of particles and fluid were evaluated to study the hydraulic performance of drill bit under different gauge geometrical parameters. Finally, the optimal geometrical parameter of gauge could be obtained according to the simulation results. Overall, the proposed approach can be used to design PDC bit gauge structure to improve the cuttings’ velocity away from bottomhole, which will result in huge improvement of ROP.

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