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The implementation of real-time corrosionmonitoring techniques can provide a reliable mechanism for detecting the overall effectiveness of chemical treatment programs and contribute to the selection and implementation of an adequate corrosion inhibitor system. Inadequate corrosion monitoring can result in an increase of both uniform and localized (pitting) corrosion activities which can lead to premature material failures. The present research was undertaken to ascertain whether linear polarization resistance (LPR), harmonic analysis (HA), and electrochemical noise (EN) in combination are suitable for the study of performance of corrosion inhibitors under a wide variety of conditions; for example, in the absence and the presence of hydrocarbons with or without the addition of corrosion inhibitors. The findings showed questionable results regarding the usefulness of the pitting factor derived from EN and HA data. In addition, statistical parameters were obtained, such as skew and kurtosis, and these results were compared with the pitting factor.

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In the past, mechanical properties have been the main criteria for selecting materials at the Miravalles Geothermal Field. Consideration of the corrosion resistance has been a secondary concern. The goal of this study was to determine the uniform corrosion rate of carbon steels currently used on pipelines (ASTM A 53, ASTM A515, ASTM A234 and API-5L) and compare this rate with the ASTM A-36 standard. The first step was the development of laboratory electrochemical and weight loss experiments. Ultrasonic thickness measurements of pipes for brine, steam and liquid-steam lines, in both straight and curve sections, showed negligible lost in material over the seven year period they have been on operation. The electrochemical study involved polarization curve analysis and corrosion rate measurements by Linear Polarization Resistance (LPR) and Electrochemical Noise Measurements (ENM). Electrochemical cells include triple and conventional testers (SCE as reference and platinum electrode as auxiliary) using brine degassed with nitrogen at 93 ± 2 ºC. According to the results, the ASTM-A36 has a similar general corrosion rate to those currently used on pipelines.