Corrosion inhibitors are widely used in oil and gas production to reduce or in best case to avoid corrosive attack of low alloyed carbon steel. The aim of this work was to investigate the influence of different parameters on inhibitors efficiency such as high flow velocity, salt content and the addition of sand particles. Furthermore some knowledge about inhibitors structure and the main mode of operation should be obtained. The results demonstrate that the imidazolin based inhibitors show the best performance over all tested conditions as long as dosed above their critical micelle concentration. Investigation of inhibitors structure was difficult and no detailed information has been received. Further investigations are necessary