Inhibitor Likelihood Success Score (ILSS) was introduced by BP, CAPCIS, Intertek and DNV (UK RR1023)as corrosion inhibitor effectiveness:
Corrosion inhibition effectiveness monitoring
1) indirect indicators testing
residue corrosion inhibitor concentration
tracer
Copper ion displacement
Iron counts and Copra correlation
2) corrosion rate monitoring
Corrosion coupons
Calliper survey for well
Electrochemical methods such as ER/LPR/ECN probes
Referring to NACE standard practice SP 0192, SP 0775 and Publication 3T 199 for further information on field monitoring and testing
Corrosion Inhibition Efficiency
As rule of thumb, 60~90% is expected and achievable.