Mitigation of Halanaerobium Driven Microbially Influenced Corrosion in Montney Pipelines Using a Continuous Cocodiamine Based Biocide Strategy

Abstract The Montney shale play in Northwest Alberta Kakwa field has experienced an unacceptable 93 microbiologically influenced corrosion (MIC) failures. Monthly monitoring revealed highly variable counts of halophilic Halanaerobium spp., confirming that MIC, not purely abiotic attack, was the dominant internal threat. A continuous chemical mitigation program was launched in late 2018. The core treatment package combined a cocodiamine based biocide (initially 50 to 200 ppm) with a synergistic film-forming corrosion inhibitor. By December 2019, the operator had deployed 79 individual biocide injection locations, failure frequency fell markedly and bacterial counts stabilized to low or nondetectable levels. Throughout 2022 a structured optimization exercise evaluated 26 mature locations; reduced microbial pressure allowed dosage rate reduction at 16 of those sites, trimming total biocide consumption without bacterial rebound. Program expansion continued as new infrastructure came online, reaching 174 pipeline injection points by mid 2025. Continuous ATP/qPCR surveillance, paired with failure tracking, confirmed sustained control while meeting corporate cost-per-barrel targets. This eight year case history demonstrates that a cocodiamine based biocide supplemented by real-time microbiology and adaptive dosing, can deliver durable MIC mitigation in high salinity shale assets. Lessons on program ramp-up, data stewardship, and step-down strategies provide a transferable roadmap for operators confronting Halanaerobium spp. dominated gathering systems.