The Role of Reservoir Microflora in the Process of Oil Displacement with Combined Physico-Chemical and Microbiological Method

A combined physico-chemical and microbiological method has been developed to enhance oil recovery. The method has been developed taking into account both oil properties and microbiological characteristics of the formation waters in White Tiger oil field. Total number of microflora in the formation water exceeded 2·107 cell/cm3. The solution of IKhN-KA system applied as a stimulating substrate increased the number of microflora by 5-6 orders. Due to active enzyme system microorganisms were capable to affect oil fixed on the porous rock. The contact of microorganisms with oil was accompanied with hydrocarbon destruction and with the accumulation of metabolism products. As a result rheological properties of oil were changed. During 10 days of microflora cultivation in contact with oil total biodestruction of n-alkanes in oil recovered from White Tiger oil field ranged from 76 to 81%. Filtration properties and oil-displacing capacity were studied using core reservoir models at 120 °C and at a pressure of 4 MPa under the conditions simulating those observed in White Tiger oil field. Porous volume of the model was 108.2 cm3, gas permeability averaged 0.712 D, core length - 26 cm. Oil displacement efficiency amounted to 57.4%. Using a combined physico-chemical and microbiological method one increased oil displacement efficiency by 14.2%

Biodegradation of Oil Hydrocarbons by Soil Microflora Activated with Photoluminescence Films

Stimulating effect of polyethylene photoluminescence films on the growth of autochthonous microflora population in oil-polluted soils has been determined under the laboratory conditions, where oil concentration in the soil was 50 g/kg. The increase in number of basic groups of microflora was accompanied with the increased activity of the enzymes, which catalyzed oxidizing processes. At the end of the experiment, on the 45-th day, oil content decreased to 15 g/kg. The analysis of the residual hydrocarbons by IR-spectroscopy has revealed absorption bands in the regions of 1710 cm–1 and 1600 cm–1. At the same time spectral coefficients С1, С2, А1 and А2 increased 1.5-3 times, while С3 and А3 decreased 1.5-2.5 times indicating oxidation processes of oil hydrocarbons. Chromatographic analysis proved the intensity of hydrocarbon biodegradation. Hydrocarbons С11-С14 completely eliminated in the test samples and the concentration of hydrocarbons with a high molecular weight decreased by 70-80%. At the same time hydrocarbon biodegradation index, determined as the ratio of the sum of isoprenoids (pristine + phytane) to the sum of n-alkanes (С17 + С18), increased 5-6 times due to the use of photoluminescence films