Improved Dynamic Biocide Testing Using Methanogenic and Sulfate-reducing Biofilms under Pipeline Conditions

Abstract An effective microbiology management strategy is pivotal to avoid biofouling, microbial influenced corrosion (MIC) and reservoir souring in oil production. MIC has often occurred despite the application of biocide chemicals into the affected systems. This is understandable since present biocide efficacy tests are performed mostly on bacterial cultures grown in suspension. Inactivation of stratified biofilms requires higher concentrations of biocide or longer exposure times compared to cells in suspension. Thus, conventional biocide tests may be insufficient to ensure the best possible biocide strategies in industrial systems with biofilm growth. Here we present a dynamic biocide test set-up with shear stress conditions similar to production environments. Biofilm activity is monitored by state-of-art Molecular Microbiological Methods and production of specific metabolites. Biocide and chaperone chemicals can be fed to the continuous reactor under conditions similar to the pipeline environment and transient effects from biocide dosage monitored. The set-up has been shown to operate with mixed prokaryotic communities of either methanogens or sulfate-reducers in biofilms. The set-up is intended to support and develop existing mitigation strategies, and enable system operators to optimize biocide management programs by comparing different treatment strategies (e.g., type of biocide, dosage duration, and dosage frequency).