Biofilm Formation and Corrosion on Carbon Steel API 5LX60 in Clayey Soil

Corrosion of buried pipelines is a matter of concern to the oil and gas industry since the time when carbon steel began to be widely used in these pipelines for the transportation of fluids. The microbial communities associated with biofilms promote modification in the surrounding environment and may accentuate the degradation of oil and gas pipelines causing leaks or even accidents. This work aimed to evaluate corrosion and biofilm formation in carbon steel API 5LX60 coupons buried in clayey soil from an industrial region in north-eastern Brazil. The average corrosion rates were determined by gravimetric test and the quantification of bacteria and fungi were using the Most Probable Number (MPN) and Colony Forming Units (CFU) techniques respectively. The results showed a great influence of clayey soil on corrosion rates and time of adherence for microorganisms on metal surfaces.

自碳钢开始广泛应用于流体输送埋地管道以来，埋地管道腐蚀问题一直是油气行业关注的重点。与生物膜相关的微生物群落会改变周围环境，进而加剧油气管道的腐蚀降解，甚至引发泄漏或安全事故。本研究旨在评估埋设于巴西东北部某工业区黏性土壤中的API 5LX60碳钢试片的腐蚀情况与生物膜形成状况。平均腐蚀速率通过重量分析法测定，细菌与真菌的定量分别采用最大可能数（Most Probable Number, MPN）法与菌落形成单位（Colony Forming Units, CFU）技术。研究结果表明，黏性土壤对腐蚀速率以及微生物在金属表面的附着时间均有显著影响。