Study on diamond bit with right trapezoidal cutters for drilling hard-compact rocks

Deep drilling has the challenges of varied strata types and complicated lithologic characters, and the problems of low rate penetration and short bit service life in hard-compact rock drilling. To solve the above mentioned drilling difficulties, a bit with right trapezoidal cutters was provided as an extensive adapted bit. The requirements of bit structure and performance of extensive adapted bit, as well as force analysis of the right trapezoidal bit were studied. Theoretical study and drilling practice indicated that the right trapezoidal bit had reasonable bit structure, which could obtain good drilling results in rocks with drillability of 7 to 9 grades. Compared to ordinary bits, the right trapezoidal bit has similar bit service life, improving penetrating rate by 21% to 24% and reducing bit cost by 15%. Consequently, the right trapezoidal bit is comparatively better than ordinary bits.