EVALUATION OF CHEMICAL TREATMENTS IN NATURALGAS SYSTEMS VS. MIC AND OTHER FORMS OF INTERNALCORROSION USING CARBON STEEL COUPONS

摘要

Monitoring of internal corrosion by some oil and gas operators has included analysis ofrngas, liquid, and solid samples in combination with corrosion detection devices such as weightlossrncoupons and electronic probes. Although these devices typically detect when significantrnuniform corrosion is occurring, they are often limited in their abilities in detecting localizedrnattack whose initiation and development may be subtle. Also, correlations of gas/liquidrncompositions with corrosion measurements are sometimes difficult. Even when localizedrncorrosion is able to be discerned, identification of the primary initiation mechanism is oftenrnoverlooked. Since understanding the basis of the corrosion attack is important whenrnimplementing mitigation measures, it became apparent that an applicable method that gave suchrninsight was crucial in administering an effective internal corrosion control program. Therefore,rnspecially prepared coupons that allowed a combination of analytical techniques to be performedrnwere developed for use in actual operating systems to detect microscopic pit initiation, includingrnthose determined to be due to microorganisms. Such coupons have been used successfully atrnhundreds of different monitoring sites in a variety of natural gas operating systems for twelvernyears with notable decreases in internal corrosion leaks and chemical expenditures.