Evaluation of slime-producing bacteria in oil field core flood experiments

Epifluorescence microscopy and carbohydrate determinations indicated that the decrease in permeability of oil reservoir sand to reclaimed sewage water was partially the result of biological plugging. Filtration and biocide addition studies demonstrated that the increase in bacterial densities and slime concentrations in flooded oil field cores appeared to be due to both deposition from the reclaimed water and in situ microbial growth and slime production. Although these biological components increased throughout the cores during flooding, the region where the water entered the core exhibited the highest cell densities and slime concentrations. The approach described in this report should be useful in predicting the potential of a water source to induce biological plugging of oil reservoir sand.