A Novel Approach to Determine the Overall Performance of a Corrosion Inhibitor in a Laboratory Testing Program

This study consists of introducing a new method that may be used to globally quantify the performance of a corrosion inhibitor in a laboratory testing program. For a given corrosion inhibitor, the new concept introduces and defines a single indicator, the Global Performance Index (GPI), which takes simultaneously into account all the corrosion measurement techniques applied in the lab in order to assess the performance of the inhibitor for a given application. The index is dimensionless and can account for both general and pitting corrosion rates. It also lumps the performances of the inhibitor as determined by all the laboratory test methods, which usually reflect the field conditions and the nature of the production system. The new method is illustrated in the case of a corrosion inhibitor selection program for a CO₂ containing wet gas pipeline. It is particularly recommended that the proposed GPI is to be used in comparing and ranking a given set of corrosion inhibitors for a production system of interest. The method can also be extended to evaluate the overall performance in the laboratory of any other non produced chemicals, such as scale inhibitors, biocides or wax inhibitors.