Electrochemical measurement techniques have been extensively investigated in laboratories and universities. For corrosion monitoring in the field on a large scale, the linear polarization resistance (LPR) technique normally is used. Several initiatives have been taken to extend LPR measurements with other electrochemical techniques in order to get more reliable information and enable to measure besides uniform corrosion, localized corrosion such as pitting, crevice corrosion and stress corrosion cracking.
Especially in the oil and gas industry, the Electrical Resistance (ER) technique is being used widely. ER probes measure metal loss very accurately at sensitivity up to 0.01 pm. Both ER and electrochemical technologies are combined with installation and evaluation of corrosion coupons. This paper describes the combination of the two technologies ER and electrochemical in one probe. The advantage of this technology is that use of corrosion coupons may be redundant if required. Evaluation of corrosion coupons is time consuming and retrieval may be dangerous. The combined probe will allow measuring the following signals online:
·Uniform corrosion by LPR with floating B-constant and harmonic distortion analysis (HDA).
·Uniform corrosion (metal loss) by ER.
·Localized corrosion (pitting, crevice corrosion and stress corrosion cracking) by electrochemical noise (EN).
·Conductance.
