Evaluation of rock abrasiveness class based on the wear mechanisms of PDC cutters

摘要

To accurately predict the wearing of a polycrystalline diamond compact (PDC) drill bit and the abrasiveness class of the rocks in the drilled stratum, macroscopic stress conditions during drilling with a PDC drill bit were obtained based on the fracture conditions of the rocks. Next, the microscopic contact characteristics of the contact surface between the stratum and the PDC drill bit were analyzed to obtain the distribution of the micro-bulge contact points of the friction pairs of the two objects within an area and to reveal changes in the contact surface temperature. Based on these results, a model was built to calculate the actual contact area between the stratum and the PDC drill bit during the sliding-induced temperature increase. The wear equation for the PDC drill bits was established by correcting the Archard equation since the major wear mechanisms of PDC drill bits are abrasive wear and adhesive wear. This wear equation was examined and validated through laboratory experiments, and then the rock-related attribute parameters were extracted and used as a basis for evaluation indicators and grading methods of rock abrasiveness.