INHIBITOR FILM PERSISTENCE MEASUREMENT BY ELECTROCHEMICAL TECHNIQUES.

A technique that uses corrosion-potential, PHI //c//o//r//r, measurements was developed to evaluate rapidly the film persistence of commercial adsorption-type inhibitors for downhole tubular treatment. It was demonstrated that the PHI //c//o//r//r measurement revealed the progressive change with time of inhibitor film in aqueous moving fluids. The advantages of PHI //c//o//r//r measurements are that film effectiveness can be monitored continuously with a simple device and that they are nonintrusive. Additional results of the tests showed that dissolved O//2, CO//2, and fluid flow drastically degraded the effectiveness of inhibitor film, and higher concentrations of inhibitors provided better performance. These indicate that simulation of process conditions is a prerequisite when the film persistence of commercial adsorption-type inhibitors is determined in a laboratory.