WEAR MECHANISM FOR DEEP-WELLS DRILLING TOOLS

Abstract

When drilling deep wells with a large diameter drill bit, it is important to ensure optimum progress with the cutting tool, effectively cutting or crushing the rock through which we are penetrating for as long as possible. When drilling a well, we encounter complex conditions at depth resulting from variables such as the strength of the rock, the load on the bit, the number of revolutions of the tool, significant temperature and pressure fluctuations and the material properties of the tools used in the drilling. The article shows how mechanisms develop due to the drilling parameters used and the complex drilling conditions, which lead to wear of the cutting unit and a decrease in efficiency. The influence of the aforementioned drilling conditions on the steel materials of the roller-cone drill bit, which is the tool we use to penetrate deeper, is reflected in the change in the material properties of the steels. These changes, which are explained in the article, lead to gradual fatigue and degradation of the materials. The wear mechanism of the cutting tool is composed of the different material properties of the steel from which the roller-cone drill bit is formed, the influence of sudden temperature changes on the steel materials and erosion processes on free, newly formed surfaces, which are the result of the erosion effect.