Application of laboratory-based rate of penetration model for polycrystalline diamond compact bit to geothermal well drilling

Abstract

The modeling of the rate of penetration (ROP) considering the degradation of drilling performance owing to bit wear is essential for planning efficient and economical drilling. In the present study, a laboratory-based ROP model for a polycrystalline diamond compact (PDC) bit is reviewed and the applicability of the model to the field data obtained in the four drilling tests performed by drilling structural boring wells in geothermal regions is investigated. It is validated that, on the whole, a parameter representing bit performance exponentially decreased with drilled length, suggesting that the decrease in ROP owing to bit wear is appropriately considered by the model, except when inherent performance of a PDC bit is not sufficiently exerted for some reason, e.g., inefficient transport of cuttings. The findings of the present study are expected to contribute to the optimization of drilling plans, including appropriate bit selection and bit life estimation.