The study of new microorganisms and processes for MEOR has been successful in several key aspects. We have been successful in isolating and characterizing sulfate reducing bacteria from oil field waters which can use the volatile fatty acids found in these waters. We have also shown that these cultures can feed each other in sequential cultures and survive in mixed culture as long as sterile conditions are maintained. When nonsterile conditions are present both organism types are successful but additional microflora develop which are the heterotrophic denitrifying bacteria. These microorganisms appear to be potentially useful in new MEOR processes and are currently being pursued. They are capable of producing large amounts of gas and also form viscosifying agents under conditions which we believe we can maintain in an oil reservoir.