Aplicação de técnicas eletroquímicas para avaliação da corrosividade de fluidos de perfuração

Abstract

One of the main stages in the exploration of hydrocarbons is drilling, in which the rock layers existing underground are perforated with the aid of a drill and the debris from the rocks is brought to the surface by the mechanical action of drilling fluids. The drilling fluid is responsible for cleaning the well and lubricating the drill, which in turn can be formed by solids, liquids, gases and some chemical additives, thus being responsible for the degradation of the equipment that makes up the drill string due to its properties. special chemicals and their composition. The present work aims to evaluate the corrosivity of these fluids on carbon steel, using electrochemical techniques. Initially, simulated fluids were produced under four study conditions. With the voltammograms obtained from the Linear Polarization technique and using the Tafel extrapolation method, the corrosion rates (g/ym2) were obtained for each simulated drilling fluid. The results obtained showed that the PL technique was not sensitive enough to show significant differences between the different simulated fluids. However, microscopic images of the steel were taken together, visually proving that there are differences in corrosion between the different simulated fluids. The other technique applied was RE (Electrochemical Noise), where, from the statistical analysis of the data obtained by the technique, it was possible to obtain values relating to noise resistance (RR). The results showed significant differences regarding the RR parameter of the fluids studied. The electrochemical noise technique with wavelet transform analysis proved to be very promising in evaluating the corrosion of the steel in question, as it showed a better interpretation compared to the polarization curves technique, showing that the electrochemical noise technique is the best choice. for corrosion studies where the electrolyte has a high electrical resistivity like the drilling fluids studied here.