RU2049911C1 - Method for development of oil field - Google Patents

Abstract

FIELD: microbiological methods for development of oil fields. SUBSTANCE: method for development of oil field includes activation of formation microflora by cyclic injection into formation of aqueous solution of nutrients with biostimulants. Introduced in the first injection cycle is biostimulant in the amount of 10^-10-10^-2 mg/ml, and is subsequent injection cycles in the amount of 10^-8-10^-4 mg/ml. EFFECT: higher efficiency. 2 tbl

Description

 The invention relates to the oil industry, in particular to microbiological methods for developing an oil field.

 Known methods for developing an oil field using microorganisms. Their essence lies in the fact that bacteria and food are introduced into the formation for their reproduction and generation of products that affect the mobility of formation fluids [1] However, this method has the disadvantage that, when mechanically transferred cultures of microorganisms cultured in laboratory conditions are ecologically excellent the environment of the oil reservoir is the death of most microorganisms due to their inability to reservoir conditions.

 Closest to the proposed method is a method including activation of formation microflora by cyclic injection of an aqueous solution of nutrients into the formation [2] The disadvantages of the method are its low efficiency and the inability to use it in water with high salinity.

The basis of the invention is the creation of a method for developing an oil field with highly saline waters, including activation of formation microflora by cyclic injection of an aqueous solution of nutrients with a biostimulator into the reservoir, moreover, in the first injection cycle, the biostimulator is introduced in an amount of 10 ^-10 10 ^-2 mg / ml, and subsequent in the amount of 10 ^-8 10 ^-4 mg / ml.

 As a biostimulant, a deoxyribonuclease (DNA-for) enzyme preparation obtained from the pancreas of cattle is used. The enzyme is a white fluffy powder used in medical practice in the form of a clear, colorless solution. Vitamins, amino acids, ectoins, which are the products of the vital activity of microorganisms, can also be used.

As used aerated nutrient salt solution K ₂ HPO _4, Na ₂ HPO ₄ and NH ₄ Cl in conjunction with the sugar-containing product. The introduction of a biostimulator along with nutrients contributes to the intensification of growth and vital activity of formation microflora and allows you to use the method in deposits containing highly mineralized water. The best efficiency of the method is achieved with the introduction of the biostimulator in batches.

 A comparative analysis of the features of the invention with the prototype allows us to conclude that the totality of the claimed features is not previously known.

 From the known level of science and technology, no inventions have been found that have features that are included in the distinctive part of the claims and which would lead to a higher technical result than the claimed invention.

 To prove the compliance of the features of the invention with the criterion of "industrial applicability" provides examples of studying the stimulating effect of deoxyribonuclease on the growth of microbial cells and the formation of gaseous products.

PRI me R 1. In a flask with a capacity of 1 liter, into which 1 liter of injected water containing stratum microflora extracted from the bottomhole zone of the well Zay-Karataevskaya area of the Romashkinskoye field is preliminarily added, salts of KN ₂ PO ₄ , Na ₂ HPO ₄ and NH ₄ Cl at concentrations of 0.1; 0.1; 0.3 g / l, as well as an aqueous solution of a sugar-containing product is added to each flask and a biostimulant is additionally introduced according to different schemes (at the beginning of the experiment and throughout it) and in different concentrations. A biostimulator is not added to the control flask.

All flasks are stoppered and placed in a thermostat at 30 ° ^C. T Periodically, the liquid sample from all flasks and produce their microbiological analysis. At the same time, the same series of flasks is prepared in the same way, with the only difference being that the flasks are closed with stoppers. Gases formed as a result of the vital activity of microorganisms through the outlet enter a vessel filled to the brim with an acidified saturated solution of sodium chloride, which was displaced from the vessel under gas pressure and collected in a graduated cylinder. The volume of solution in the cylinder corresponded to the volume of gas formed. They work with water with a salinity of 30 g / l.

 The research data are given in table 1.

 As can be seen from the data in table 1. the introduction of a biostimulator stimulates the vital activity of the stratum microflora, and the higher the concentration of the biostimulator, the more this effect is manifested (experiments 1,4,5,6). Next, an experiment was conducted on the additional introduction of a biostimulator after 28 hours (experiments 2,3,7,8). As can be seen, the introduction of a biostimulator 28 hours after the first portion is introduced further stimulates the process of microbial cell formation and gas formation by formation microflora.

PRI me R 2. Determination of the impact of input biostimulant on the development of reservoir microflora in mineralized waters. To do this, the experiments are set as described above, but using produced water with a salinity of 50, 70, 90, 100, 150 g / l. The regimen of administration of the biostimulant: initially 10 ^-10 mg / ml, and after 28 hours another 10 ^-4 mg / ml.

 The number of microorganisms formed (denitrifying bacteria (DNB) and hydrocarbon-oxidizing bacteria (DRR)) depending on the salinity of the water are given in Table 2.

 As can be seen from the data of Table 2, the addition of the biostimulator according to the invention promotes the survival of formation microflora in waters with high salinity, while according to the known method, salinity of more than 50 mg / ml is toxic to formation microflora.

 EXAMPLE 3. Studies are carried out to determine the dependence of the change in the number of microbial cells (hydrocarbon-oxidizing bacteria) on the addition of a DNase biostimulator in the water of the Romashkinskoye field on the time of administration of the second portion of DNase after 8.24.32 hours in various concentrations. Studies are carried out under aerobic conditions for 10 days.

 The results are shown in table.3.

 As can be seen from the data in Table 3, the time of administration of the second portion of the biostimulant does not affect the number of microbial cells formed.

 The effectiveness of the method is checked by the results of oil displacement by injection of reagents according to the known and claimed methods in laboratory conditions. At the same time, the formation association of microorganisms extracted from the bottom-hole zone of the Zai-Karataevskaya area of the Romashkinskoye field is used as microorganisms. The reservoir components used were oil, water with a salinity of 30-150 g / l and core material extracted from the bottomhole zone of the same well.

 The experiments are carried out on reservoir models, which are a system of two elements, which are metal tubes with a diameter of 2 cm, a length of 170 cm, filled with quartz sand. One of the elements has a permeability 10 times greater than the other, which is achieved by the selection of appropriate sand fractions. The porous medium of each element is individually saturated with oil, then the elements are combined into a model so that it has one common input developing to each element and separate outputs from each element (OST 39-195-86).

 Oil displacement data are given in table 4.

PRI me R 4. The displacement of oil by a known method is carried out by pumping a nutrient solution, representing an aqueous solution of salts of K ₂ NRA ₄ , Na ₂ HPO ₄ , NH ₄ Cl with molasses. Prior to the introduction of the salt flakes, a stratified microflora was introduced, capable of carrying out a microbiological process. After injection solutions produce models exposure at ³⁰ ° C for 7 days. Next, the models are connected to the injection of water for 20-24 hours. The additional increase in oil is 6.2%
PRI me R 5. Similar studies are carried out with the introduction into the aqueous solution of nutrients of the biostimulator in the first cycle in the amount of 10 ^-10 mg / ml, in the second cycle of 10 ^-4 mg / ml. An additional increase of 8.3%. In experiments 3-6, data are presented on the study of the effectiveness of the method with different biostimulant contents.

The advantages of the proposed method:
allows to increase the growth of oil recovery by 7.1-9.2%
microbiological methods are environmentally friendly, since the products formed in the formation are harmless and biodegradable;
the proposed method is cheap and affordable, since it does not require the injection of specially prepared microflora into the reservoir, but uses the microflora existing in the reservoir;
It is used in heavily watered deposits, where the use of other physicochemical technologies is not economically viable.

Claims (2)

1. A method for development of oil fields, comprising reservoir microflora activation by cyclic injection in aqueous nutrient reservoir, characterized in that the aqueous nutrient solution administered biostimulant, wherein the first cycle number is biostimulant 10 ^{- 1 0} 10 ^{- 2} mg / ml and in subsequent 10 ^{- 8} 10 ^{- 4} mg / ml.  2. The method according to claim 1, characterized in that pancreatic deoxyribonuclease is used as a biostimulant.

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