The CLEAN BIOCIDE project: Halophilic plant extracts as natural corrosion inhibitors and biocides for oil field application

Offshore oil production is subjectable to internal corrosion, which can occur through microbiologically influenced corrosion (MIC) caused by biofilm forming sulfur-reducing bacteria (SRB). To mitigate MIC, the oil and gas industry relies primarily on biocides and mechanical cleaning. Halophytes (salt-tolerant plants), produce a variety of bioactive compounds and some of these compounds have antimicrobial activity. MIC was studied on carbon steel coupons inoculated with anaerobic sediment from the Wadden Sea (Denmark) to mimic MIC from oil production facilities in the North Sea. The coupons were treated with extracts from selected halophytes. Using H2S as activity indicator for SRBs and ATP for general microbial activity in the liquid phase, initial trials have shown a significant reduction in H2S conc. in experiments treated with extracts, compared to controls, indicating a reduction of SRB species. Next generation 16S rRNA amplicon sequencing of DNA from Bacteria and Archaea, proved a significant shift away from SRBs in the microbial composition when compared to samples not treated with extracts. Visual reduction in corrosion was observed on coupons. Long-term solutions to prevent MIC using natural antimicrobial compounds from halophyte plants are beeing developed in this study.