High performance corrosion inhibitors with lower toxicity are now available commercially. For this reason, the performance of these "green" corrosion inhibitors selected carefully in the laboratory and optimized on the field is not questionable, provided field conditions remain stable and adequate for the chemical to be available at the pipe wall. It is therefore the responsibility of the operator to ensure that these conditions are met. This study gives an example where the availability of a "green" corrosion inhibitor at the pipe wall had to be enforced by imposing a tight control on operating conditions. The use of the different tools available to the corrosion engineer is described, and the relevance of shear stresses is discussed.