RU2195549C2 - Method of producing high-viscosity oil - Google Patents

Abstract

FIELD: oil producing industry, particularly, microbiological methods of high-viscosity oil production. SUBSTANCE: method includes injection of displacement agent through injection well, withdrawal of product through producing wells, and use of thinning composition for injection. Thinning composition is used in the form of hydrocarbon-oxidizing bacteria with nutrient salts in aqueous solution with the following ratio of components, mas.%: hydrocarbon-oxidizing bacteria, 0.05-0.15; nutrient salts, 0.07-0.3; water, the balance. In preferable version, method is realized by cyclic injection of thinning composition. Technology of oil production is safe. EFFECT: reduced oil viscosity, facilitated oil recovery. 2 cl, 1 tbl

Description

 The invention relates to the oil industry, namely to microbiological methods for the production of high-viscosity oil.

 A known method of microbiological treatment of an oil reservoir, including the injection of microbial biomass of the biochemical production of protein-vitamin concentrates (see RF patent 2118677, MKI E 21 V 43/22, publ. 1998).

 This method is not effective enough due to the fact that the decrease in oil viscosity occurs only due to the formation of gas, the microbial biomass used does not affect heavy oil fractions, and the nutrients contained in the waste are a good medium for the formation of sulfate-reducing bacteria that cause corrosion of oilfield equipment.

A known method of producing highly viscous waterlogged oil, including reducing the viscosity of oil by injecting a mixture of a surfactant with a solvent (see ed. Certificate. 1798487, MKI E 21 V 43/22, publ. 1993)
However, this method is not effective enough, and also when using the method requires constant fishing control.

 The closest in technical essence and the achieved effect is a method for the production of highly viscous oil by injection of a diluent composition, including anionic surfactant (ACAS), nonionic surfactant (NPAB), alkali metal hydroxide and water of Lorcalcium type (see RF patent 2062868, MKI E 21 B 43/22, publ. 1996).

 However, this method is ineffective in the production of high-viscosity oil by pumping a fluidizing agent through injection wells due to the need to pump large volumes of reagents, which leads to a more expensive production process.

 The present invention is based on the task of creating a highly efficient and environmentally friendly method for the production of highly viscous oil, which allows to increase oil recovery by reducing the viscosity of oil and its desulfurization.

The problem is solved by creating a method for producing highly viscous oil, including pumping a displacing agent through an injection well, taking products through production wells and using a diluent composition when injecting, and hydrocarbon-oxidizing bacteria with nutrient salts in an aqueous solution are used as a diluent in the following ratio of components, wt .%:
Hydrocarbon-oxidizing bacteria - 0.05-0.15
Nutrient salts - 0.07-0.3
Water - Else
In an advantageous embodiment of the method, the injection is performed cyclically.

As hydrocarbon-oxidizing bacteria (BDS), bacteria are used that have the ability to reduce the viscosity of oil and desulfurize it, for example: - Pseudomonas species-45 strain isolated from gas station from soils contaminated with oil products from the collection of the Institute of Biochemistry and Physiology of Microorganisms, Pushkino,
- a bacterial biological product, which is an association of microorganisms Pseudomonas stutzeri, 367-1, Rhodoccocus erythropolis, 367-2, Rhodoccocus maris, 367-5, Rhodoccocus erythropolis, 367-6, Rhodoccocus maris, 367-4 and yeast microorganisms Candida sp. -3, isolated from produced waters of the Bondyuzhskoye oil field;
- a bacterial preparation consisting of microorganisms of the genus Acinetobacter sp., from the collection of the Berdsk plant of biochemical preparations.

 For formations that have their own microflora, DRR is selected that are compatible with reservoir microflora, and, based on this, the amount of DRR in the composition is determined so that the total amount of DRR is within the claimed range.

As nutrient salts, nitrogen and phosphorus-containing salts or mixtures thereof are used, for example:
- nitric acid ammonium (NH ₄ NO ₃ ) according to GOST 2-85;
- monopotassium phosphate (KH ₂ PO ₄ ) according to TU 6-09-5324-87;
- disodium phosphate (Na ₂ HPO ₄ ) x12 H ₂ O according to GOST 4172-76;
- sodium acetate (CH ₃ COONa) according to GOST 2080-76.

 Hydrocarbon-oxidizing bacteria and nutritious salts are commercially available in powder form and are easily mixed, therefore, an aqueous solution of a mixture of these components can be prepared under field conditions directly at the place of use for the preparation of an aqueous solution.

 A new set of claimed essential features allows us to obtain a new technical result, namely, to create an effective and environmentally friendly way to produce highly viscous oil by reducing the viscosity of oil and its desulfurization.

 An analysis of the known solutions selected in the search process showed that in science and technology there is no object with the claimed combination of features and the presence of the above properties and advantages, which allows us to conclude that the claimed object meets the criteria of "novelty" and "inventive step".

 To prove the compliance of the claimed invention with the criterion of "industrial applicability" we give specific examples to determine the effectiveness of this method.

The technology for the application of pilot works is as follows. A tanker of the AC type is installed near the well and, with stirring, a diluent is prepared. To prepare 200 m ^{3 of a} diluent composition, 100-300 kg of DRR, 100-400 kg of ammonium nitrate, 20-100 kg of disodium phosphate, 20-100 kg of monopotassium phosphate and 20-200 kg of sodium acetate are added to fresh or weakly mineralized water with stirring.

The thinning composition is injected using a pump unit of the CA-320 type into a reservoir containing highly viscous and sulphurous oils flooded with fresh or low-mineralized waters. The composition is injected in 4-10 cycles of 200 m ³ in each cycle. After each cycle, an exposure is made for the reaction of the diluent composition with oil and then the injection of the displacing agent is resumed.

 The effectiveness of the proposed method is determined in laboratory conditions to reduce the viscosity of oil and the total sulfur content in the samples before and after treatment with a diluent composition.

 The viscosity of the oil is measured on a Mettler Rotary Viscometer Contraves Low Sher-40, and the sulfur content is determined using an Oxford Instruments Industrial Analysis Group Lab-x 3000 analyzer.

As raw materials, oil is used with the following physicochemical characteristics: density 0.0245 g / cm ³ ; viscosity at 23 ^o C 220.8 MPa • s; sulfur content of 4.43%, occurring at a depth of 505 m in carbonate reservoirs with porosity of 9.8% at a pressure in the reservoir of 60 atm, with a salinity of formation water of 60 g / l.

 The research results are shown in the table.

 Example 1

While stirring, add 1.0 g of hydrocarbon-oxidizing bacteria to the laboratory flask - Pseudomonas sp strain, - 45.10 g - ammonium nitrate, 0.2 g - monopotassium phosphate, 0.2 g - disodium phosphate, 0.5 g - sodium acetate, 997 ml - formation water and oil in the amount of 250 ml. The flask is aged for 14 days at a temperature of 30 ^o C. Next, determine the viscosity of the oil and the amount of total sulfur in it (see table, example 1).

 Examples 2-9 are carried out in a similar manner, using various bacterial cultures as the DRR (see table, example 2-9).

The flask is aged for 14 days at a temperature of 30 ^o C. Next, determine the viscosity of the oil and the amount of total sulfur in it (see table., Example 1).

 Example 10 (prototype).

 In a laboratory flask in 898 ml of potassium chloride-type produced water with a chloride content of up to 9%, add 7.0 g of anionic surfactant-TEAS-M, 12.0 g of nonionic surfactants - OP-10, 83.0 - KOH and oil in an amount of 250 ml . The final viscosity of the oil is determined (see table, example 10).

 The proposed method for the production of high-viscosity oil in comparison with the prototype allows to achieve a decrease in the viscosity of oil, as well as additionally carry out its desulfurization.

 The use of compositions based on microbial cells does not adversely affect the environment.

Claims (1)

1. A method of producing highly viscous oil, including pumping a displacing agent through an injection well, selecting products through production wells, using a fluidizing composition when injecting, characterized in that hydrocarbon-oxidizing bacteria with nutrient salts in an aqueous solution are used as a fluidizing composition in the following ratio of components, wt . %:
Hydrocarbon-oxidizing bacteria - 0.05-0.15
Nutrient salts - 0.07-0.3
Water - Else
2. The method according to p. 1, characterized in that the thinning composition is pumped cyclically.

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