Seals for Geothermal Roller Drill Bits

Abstract

A significant factor contributing to short bit life and attendant high costs for geothermal drilling is the lack of seals for elevated temperatures. To assist development of a high-temperature seal, a test facility was constructed to simulate the seal environment in a roller bit during geothermal drilling. Although none of the tested elastomers appear suitable for compression seals above 200°C, extensive testing was performed to determine their exact limits. Several new heterogeneous seal designs were found usable to higher temperatures.

Field Performance of a Hydrodynamically Lubricated Bearing Seal for Rock Bits

“…The magnitude of these pressure fluctuations depends on the details of the geometry; however, laboratory simulations have reported magnitudes as high as ±50 to ± 100 psi. 9,10 The bearing seal is required to accommodate these relative cone-to-arm motions and the possible pressure fluctuations.…”