Evaluation of the Wear Resistance and Electrochemical Behavior of Drill Bits for Drilling Oil and Gas Wells

Abstract

This work aims to study the relation between the hardness and behavioral wear of tungsten carbide inserts (TCI) and polycrystalline diamond compact (PDC) cutters, used as drill bits for drilling oil and gas wells, through wear testing conducted using the pin-on-disc test and the measure of microhardness Knoop test. The morphology of the worn surface was characterized using scanning electron microscopy (SEM), and the chemical composition was taken before and after the wear test inside the tracks using energy-dispersive X-ray spectrometry (EDX). Additionally, the behavior of the corrosion resistance was evaluated with the electrodynamic polarization technique and was compared with a coating of diamond-like carbon (DLC) in order to determine whether this coating applied to tool steel could serve as a substitute for insert-based coatings in future applications, as its cost is lower than that of the inserts. A paragraph discusses what characteristics must be taken when selecting or manufacturing materials for drill bit applications. In conclusion, it was found that the TCI insert presented cracks in the test tracks, while the PDC insert showed soft wear; this was due to the uncertain hardness, which was greater than the indenter used. Concerning the Tafel test, the curves showed that the PDC insert presents better behavior under corrosion; however, the DLC can be a good substitute.