Study of the effect of test parameters on the assessment of steel resistance to carbon dioxide corrosion

Abstract

Carbon dioxide (CO2) corrosion is one of the most dangerous types of destruction of metal products in the oil and gas industry. The field steel pipelines and tubing run the highest risk. Laboratory tests are carried out to assess the resistance of steels to carbon dioxide corrosion. However, unified requirements for certain test parameters are currently absent in the regulatory documentation. We present the results of studying the effect of the parameters of laboratory tests on the assessment of the resistance of steels to CO2 corrosion. It is shown that change in the parameters of CO2 concentration, chemical composition of the water/brine system, the buffer properties and pH, the roughness of the sample surface, etc., even in the framework of the same laboratory technique, can lead in different test results. The main contribution to the repeatability and reproducibility of test results is made by the concentration of CO2, pH of the water/brine system, and surface roughness of the samples. The results obtained can be used in developing recommendations for the choice of test parameters to ensure a satisfactory convergence of the results gained in different laboratories, as well as in elaborating of a unified method for assessing the resistance of steels to carbon dioxide corrosion.