High-temperature wear mechanism of roller cone bit spiral seal

Abstract

When drilling, the spiral seal of the roller cone bit and the journal are prone to collision and wear, and the friction heat and downhole high temperature will affect the wear process. The friction and wear experiments of the spiral seal material (20CrNiMo–40Cr) at different temperatures were carried out to study the wear mechanism of the spiral seal and journal of roller cone bit at high temperatures to determine the wear amount, friction coefficient and main wear forms. The wear model of friction pairs is established based on the Archard wear model and experimental results; The wear results at different temperatures are obtained by establishing the spiral seal structure model and simulation research of the roller cone bit. The results show that:(1) Through the friction and wear experiment of friction pair materials, the higher the temperature is the greater the wear amount and friction coefficient are. When the temperature exceeds 100 °C, the wear amount and friction coefficient begin to decline with the increase in temperature. By observing the wear surface morphology, abrasive and adhesive wears occur simultaneously, and the main wear form is adhesive wear under high-temperature conditions.(2) The maximum temperature rise caused by friction and the relationship between wear volume and time at different temperatures are obtained through the simulation of the spiral seal structure. Taking the groove depth value as the index to evaluate the sealing effect, the roller cone bit works in the temperature range (25 °C-400 °C), and high-temperature wear does not affect its sealing performance.