Abrasion Rule of Polycrystalline Diamond Compact Bit Cutter

摘要

To decrease polycrystalline diamond compact(PDC) cutter abrasion and improve the PDC bit's drilling performance, based on the academic analysis, a series of rock cutting experiments were made on a lathe with a single PDC cutter to understand better the effects of cutting angle, height of protrusion, linear velocity and the indentation hardness on PDC cutter wear. By the experiments, it shows that the different cutting angles are suitable to different heights of protrusion; for example, the optimal protrusion height of PDC bit with cutting angles of 25° is 3 mm. Also, the PDC abrasion volume and the linear velocity are found to be in direct proportion during well drilling operations, and the PDC abrasion volume can be obtained by the formula V=δμpFvt. Besides, the PDC cutter's abrasion volume is in inverse proportion to indentation hardness. It is suggested to select the PDC bit with larger cutting angle when drilling the rock samples with larger indentation hardness and select the smaller cutting angle when drilling the soft formation. Field drilling tests of five bits with different cutting angles are conducted to verify the validity of the laboratory tests. The drilling experiment results agree with the results obtained by the laboratory tests. The results of this study can be applied to each PDC cutter on a given bit; then, the contributions of every cutter can be integrated to determine the bit performance. Also, this study can serve as a guidance for developing new PDC bit design that are optimized for specific rock formations.