Effects of phosphonates in the microbiological activity of SRB and APB in oil fields

摘要

Biocorrosion of metal pipelines in the oil and hydrocarbon industry is frequently linked to the presence of Sulfate Reducing Bacteria (SRB) and Acid Producing Bacteria (APB). Suggested mechanisms of SRB induced corrosion are an accumulation of corrosive metabolites like hydrogen sulfide or cathodic depolarization. The APB produce organic acids as results of its metabolism. A biocide can be defined as a chemical agent that is capable of destroying living organisms. Microbiological studies have been conducted in the field to assess the efficiency of a biocide with a base of phosphonate derivatives. Tests performed were microbiological analysis of APB and SRB inoculation by taking a liquid sample directly from an oil field well. After incubation, the colonies were counted per ml of sample (UCF). Positive APB and SRB samples were selected for inoculations tests in the presence and absence of biocide. Tests were performed at four concentrations (50 ppm, 100 ppm, 150 ppm and 200 ppm) of the sample liquid bactericidal at different times (0, 10, 20, 40, 60, 80, 100 and 120 minutes). High bactericidal efficiency values for the biocide were recorded exceeding the 96% efficiency from the 100 ppm concentration. The bactericidal proved highly effectiveness inhibiting the growth of SRB with no registered value greater than 10 cfu / ml, indicating greater than 90% efficiency. The active principle of the biocide tested (phosphonate derivatives), proved consistency over time, preventing bacterial growth in the 8 timelines.