Cutting Migration and Core Disturbance Caused by the Hydraulic Structure of Pressure- and Gas-Maintaining Coring Bits

Gas disaster prevention and control is essential to coal mine safety production, with accurate measurement of gas pressure content being the challenging key aspect. Pressure- gas-maintaining coring devices can characterize cores in situ achieve this measurement. As an important part these devices, hydraulic structure bit plays a decisive role migration, rate, core disturbance bottom-hole cuttings, studying thus great significance. In paper, fluid simulation software FLUENT used carry out numerical flow field study cutting movement caused by bits different structures. The results show that (1) best nozzle azimuth angle 75° beneficial discharge reduces scouring effect drilling on core. (2) larger diameter is, weaker removal ability drill smaller fluid. optimal 12 mm. (3) Adding sluice channel inside water barrier ring reduce erosion (4) Bits rectangular inner passage promote migration. Field application designed performs well, research provide reference for optimization retention.