Rock Bit Metal Bearing Seal Technology

This paper describes new rock bit bearing seal technology that is just beginning to be applied to difficult drilling applications in West Texas. The conventional elastomer seal may have limitations in applications where there is elevated temperature, oil based mud, or high bit rotary speed. The use of hard metal rather than an elastomer as the primary sealing element improves bit performance in these environments. High temperature, oil mud and high RPM associated with downhole motor drilling are present in horizontal drilling in the Williston Basin of North Dakota. The results of testing metal seals in Williston Basin horizontal drilling are presented along with recent metal seal performance in West Texas. Metal seal bits have shown to be much more reliable and consistent than elastomer seal bits in these applications. Longer hours and higher reliability have reduced the number of bits required and thus lowered the cost of wells drilled. The improved percentage of seal effective bits has also lowered the risk of costly fishing jobs due to bearing failure.