Microbial products and uses thereof to improve oil recovery
This invention relates to compositions and methods of microbial enhanced oil recovery using biochemical-producing microbes. In specific embodiments, the methods of the subject invention comprise applying a bio surfactant-producing bacteria and/or a growth by-product thereof to an oil-producing site. In preferred embodiments, the bacteria is a strain of Bacillus in spore form. In some embodiments, the methods further comprise applying the bacteria with a yeast fermentation product, an alkaline compound, a polymer, a non-biological surfactant, and/or one or more chelating agents. Advantageously, the subject invention can be useful for stimulating the flow of oil from a well, as well as dissolving scale present in an oil-bearing formation.
1. A method for enhancing the amount of oil recoverable from an oil-bearing formation, wherein the method comprises:
applying to the formation a yeast fermentation product comprising a broth in which a Wickerhamomyces anomalus or Starmerella bombicola yeast was cultivated, wherein said broth comprises a glycolipid biosurfactant produced by said yeast, and wherein said broth contains yeast cellular components but no living yeasts;
wherein said method further comprises applying to the formation:
a solvent selected from the group consisting of isopropyl alcohol and ethanol; and
a chelating agent comprising a mixture of two or more of citric acid, sodium citrate, and EDTA.
2. The method of claim 1 , further comprising administering one or more polymer compounds to the formation.
3. The method of claim 2 , wherein the one or more polymer compounds are selected from the group consisting of xanthan gum, guar gum, hydrogels, polysaccharide, and cellulose polymers.
4. The method of claim 1 , further comprising administering one or more non-biological surfactants to the formation.
5. The method of claim 1 , wherein the method enhances oil recovery and also dissolves scale deposits present in the formation.
6. The method of claim 1 , wherein the yeast fermentation product, the solvent and the chelating agent are mixed with water prior to application, and wherein the glycolipid biosurfactant is a sophorolipid and the solvent is isopropyl alcohol.
7. The method of claim 1 , wherein the yeast is Starmerella bombicola.