Monitoring oil pipeline MIC and its mitigation offline using a true biofilm test kit and a mechanistic MIC model

Paper ID: C2025-00286 ABSTRACT: Microbiologically influenced corrosion (MIC) is caused by microbial biofilms. A convenient disposable biofilm/MIC test kit (patent-pending) was used tomonitor internal oil pipeline biofilm and MIC. It used two solid-state electrodes in a sealed 10 mL serum vial for electrochemical scans including linear polarization resistance (2 min per scan) and potentiodynamic polarization (20 min per scan) using a portable potentiostat. The biofilm/MIC test kit was capable of detecting biofilm growth, distinguishing corrosion types (abiotic vs. different types of MIC), assessing biofilm corrosivity and biocide efficacy. Moreover, it provided transient information to complement traditional coupon weight loss, sessile cell counting, and biofilm imaging data. Oilfield oil-water liquid samples were assessed using the biofilm test kit and aforementioned traditional assays for biofilm growth, corrosivity and biocide efficacy. The main corrosive microbes were identified as sulfate reducers based on next generation sequencing data. With the calibration using weight loss data, the corrosion resistance (Rp) from linear polarization resistance and corrosion current density (icorr) from Tafel scans were correlated with biofilm aggressiveness in our mechanistic model. The correlations were also modified to include biocide impact. With the correlations, the model was used to predict uniform corrosion and pitting corrosion as well as biocide efficacy.