Browsing by Author "Samuel, O. B."
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Item The bio-corrosive nature of injection water sources used in the Nigerian oil and gas industry.(National Institute of Ecology, 2013) Okoro, Chuma C.; Amund, Olukayode O.; Samuel, O. B.The bio-corrosive nature of injection water used in the Nigerian oil and gas industry from different sources such as seawater, produced water, brackish water, fresh and underground water were investigated with special emphasis on some of their components which enhance corrosion such as microbial activity, dissolved oxygen and presence of dissolved substances such as chlorides, sulfates and ammonia. Our investigation reveals that seawater, produced water and brackish water had higher salinity, conductivity, concentrations of dissolved oxygen, TDS, sulfate, organic nutrients, sulphate reducing bacteria (SRB), acid producing bacteria (APB) and higher corrosion rates (0.24-0.56 mm yr-1) than fresh and underground water whose corrosion rates ranged between 0.06-0.08 mm yr-1. Our study also established high correlation between corrosion rates and the concentrations of Fe2+, SRB, APB, TDS, DO and conductivity in all injection water samples examined in the study. The role of microorganisms in enhancing corrosion was also clearly established in some samples.Item Biologically Active Solid Deposits in Biocide treated Oil and Gas pipelines from a Nigerian Onshore Oil Production Facility(National Institute of Ecology, 2013) Okoro, C. C.; Amund, Olukayode O.; Samuel, O. B.Pipelines transporting crude oil, produced water and gas from an onshore oil producing facility in Nigeria are subject to frequent corrosion failures despite treatment programs with chlorine (0.5mg L-1) and sodium azide (0.2 mg L-1). Solid deposit samples from 6 corroded pipelines were analyzed chemically and biologically to determine whether the corrosion episodes were as a result of microbial activity. Microbiological analysis showed relatively high concentrations of microorganisms associated with corrosion such as SRBs (103-105 cell g-1) and APBs (103-107 cells g-1) while chemical analysis showed evidence of corrosion products such as iron II, calcium, sulfide, carbonate and bicarbonate. Chemical analysis also revealed that environmental conditions such as availability of nutrients, pH, moisture and redox potential were favorable for the growth and proliferation of these microorganisms. All the pipeline samples that were investigated recorded remarkable corrosion rates that ranged from 0.065-0.30 mm yr-1 but the rates were higher in chloride treated pipelines. Our investigation revealed that the solid deposit samples were biologically active and pipeline corrosion was as a result of microbial activity. Thus the prevalence of bio-corrosion is likely to be higher in cases where routine pipeline cleaning and checks are not strictly adhered to despite regular biocide treatment programs