Wear and Degradation of Drilling Performance of Polycrystalline Diamond Compact Bit in Laboratory Test

Polycrystalline diamond compact (PDC) bits have been widely used in oil and gas well drilling and have recently also begun to be used in geothermal well drilling. In the present study, the drilling performance and wear of a PDC bit were assessed by laboratory drilling tests. The correlation between the progress of bit wear and some indexes of rock abrasivity was discussed referring to the test results. The rate of penetration was formulated as a function of weight on the bit using the drilling test results for other PDC bits with the same geometric design as that used in the present study and introducing a parameter that represents the drilling performance of the bit. The parameter was found to be exponentially reduced with the wear volume of the polycrystalline diamond layer. The parameter was also found to be associated with the drilled rock type.