STRAIN RHODOCOCCUS ERYTHROPOLIS HO-KS22, HAVING HIGH UREASE ACTIVITY, CAPABLE OF GENERATION OF AN OIL-DISPLACING AGENT BIO-SURFACTANT IN AN OIL RESERVOIR Russian patent published in 2020 - IPC C09K8/582 C12N1/26 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil industry and can be used in methods of improving oil recovery using bacterial strains. Strain Rhodococcus erythropolis HO-KS22, deposited in VKM as Ac-2807D, capable of generation directly in oil reservoir of oil-displacing agent (bio-surfactant) due to use of hydrocarbons of oil, having high urease activity, which results in strong alkalization of the medium when urea is used as a nitrogen source. Alkalinisation of the medium initiates deposition of carbonate salts of calcium and magnesium, which changes the formation intake profile and leads to additional displacement of oil from previously washed-out areas of the oil-containing matrix. Decomposition of urea leads to sedimentation of carbonates in washed zones of formation, change of direction of hydrodynamic flows and increased coverage of deposit by flooding. As a result of action of bio-surfactant and increase of pH of formation water increases mobility of oil and increases degree of its extraction from formation.

EFFECT: technical result of using the strain Rhodococcus erythropolis HO-KS22 is improved oil recovery due to formation of bio-surfactants directly in the contact zone with oil, which leads to considerable reduction of interfacial tension and reduced effect of capillary forces retaining oil in micropores of oil-bearing rock.

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