Bacteria and its use in a microbial profile modification process
AssigneeChevron Research Company
InventorsRichard S. Silver, Pamela M. Bunting, William G. Moon, Willard P. Acheson
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Abstract
The present invention is a bacteria and its use in a Microbial Enhanced Oil Recovery (MEOR) process. Any one of two newly isolated strains of bacteria are injected downhole in a petroleum reservoir to modify its profile. This bacteria has the capability to plug the zones of higher permeability within the reservoir so that a subsequent waterflood may selectively enter the oil bearing less permeable zones. The injected water is used to drive this oil to an area where it may then be recovered.
Claims28
A process for enhancing oil recovery by improving the sweep efficiency of a water flood through an oil producing reservoir which has zones of relatively high permeability and saline connate water, comprising the steps of:
- isolating a bacterium that has the following characteristics:
- it is motile;
- it is a facultative anaerobe;
- it is at least halotolerant;
- it is at least thermotolerant;
- it produces an exopolymer;
- and
- it sporulates;
- preparing a suspension of said bacterial spores or cells or mixtures thereof;
- injecting said suspension into an oil producing reservoir where said spores or cells may become lodged in zones of relatively high permeability;
- and
- contacting said spores or cells with a nutrient solution to induce them to plug said zones of relatively high permeability, said nutrient solution comprises a source of phosphate nutrient as polyphosphate.
An enhanced oil recovery process comprising selectively plugging relatively high permeable zones within a petroleum reservoir using a biologically pure strain of Bacillus licheniformis, NRRL No. B-18179 or its spores or mixtures thereof.
An enhanced oil recovery process comprising selectively plugging relatively highly permeable zones within a petroleum reservoir using a biologically pure strain of Bacillus licheniformis, NRRL No. B-18178 or its spores or mixtures thereof.
An enhanced oil recovery process comprising selectively plugging relatively highly permeable zones within a petroleum reservoir using a biologically pure strain of Bacillus licheniformis, NRRL Nos. B-18178 and 18179 or their spores or mixtures thereof.
A process for modifying the profile of a petroleum reservoir to enhance oil recovery from relatively high permeability zones, comprising:
- preparing a biologically pure form of Bacillus licheniformis, NRRL No. B-18178 or B-18179;
- forming spores of B-18178 or B-18179;
- separating the spores from cell debris and proteins;
- flowing the spores into a relatively high permeability zone in a petroleum reservoir;
- and
- contacting the spores with a nutrient solution to facilitate growth and exopolymer production.
Dependencies are inferred from the claim text.