Abstract
In order to improve cleaning efficiency of dual-diameter PDC bit, the total flow area, inclination angle and azimuth angle of bit’s pilot and reaming nozzles were analyzed. By numerical simulation, the velocity, pressure and particle distribution of bottomhole are obtained. The results show that low pressure area of pilot downhole decreases while low pressure of reamer downhole increases with the increase of total flow area. The mud velocity of central bottomhole has the negative relationship with inclination angle and positive relationship with azimuth angle. Best cleaning efficiency can be achieved when total flow area is 12 cm2, inclination angles of pilot and reamer are respectively 15° and 25°, and azimuth angles of pilot and reamer are respectively 60° and 30°.
© 2020 Turbomachinery Society of Japan, Korean Fluid Machinery Association, Chinese Society of Engineering Thermophysics, IAHR
