Methodology of Batch Inhibition Applied for Top and Bottom of the Line Corrosion Mitigation

Quaternary ammonium compounds that exist as a waxy solid at low temperatures typically exhibit excellent persistency when applied in batch corrosion inhibitors (BCI), which are one of the mainstays of corrosion protection for many integrity management strategies worldwide. The performance of these type of corrosion inhibitor is often evaluated in laboratory conditions, prior to field application. The most common laboratory method to characterize BCI involves the filming procedure called the dip and drip method, where the steel specimen is immersed in neat BCI for a few seconds before testing. However, this dip and drip method carries several drawbacks, one of them being the likely oxygen (O2) contamination what is sure to impact the results. In addition, extrapolation of laboratory measurements to field conditions are often performed without rigorous modeling, and application parameters are consequently suboptimal; this results in inefficient or, at worst, ineffective protection being provided to the steel in the corrosive environment. In this research, a BCI testing procedure was developed for bottom of the line corrosion (BLC) that can maintain stable water chemistry and avoid O2 contamination, with the potential to be adapted for top-of-the-line corrosion (TLC) environments. The pre-filming procedure of BCI and corrosion testing can be done in the same glass cell which eliminates O2 contamination and have capabilities to remove residual inhibitors after the pre-filming process. The linear polarization resistance (LPR) method was utilized to measure in situ corrosion rates. UV-vis spectroscopy was applied to monitor corrosion inhibitor concentrations, which showed repeatable results and demonstrated the accuracy and efficiency of this methodology of batch inhibition applied for BLC and TLC mitigation.Corrosion leads to economic costs equivalent to 4-5\GNP), environmental contamination, infrastructure degradation, safety risks, reputational damage, and litigation 1. However, 35\. In the industry of transportation of oil and gas, much effort has been made to understand the role of CO2 in internal corrosion of pipelines, due to the ubiquitous presence of the corrosive gas in wells and geologic formations 3-8. Main mitigation strategies include use of coatings, cathodic protection, corrosion resistant alloys, and organic corrosion inhibitors. The use of corrosion inhibitor presents many advantages for internal corrosion. First, inhibitors can be directly injected in the flow without affecting production and their use are relatively versatile as injection rates can be adjusted easily 9. Secondly and most importantly, its associated costs are low compared to other mitigation techniques 9.