SU1652337A1 - Method for enhancing oil yield in secondary oil recovery - Google Patents

Abstract

The invention relates to the technology of mining, in particular to methods of enhanced oil recovery, and can be used to increase oil recovery from watered wells. The purpose of the invention is to increase the effectiveness of microbiological effects on the formation, to simplify and cheapen the method. The essence of the invention is that wastewater from the lactic acid production is pumped into the flooded oil reservoir as a nutrient medium for native microflora. The use of wastewater of lactic acid production in the amount of 5-15% of the volume of produced water contributes to the activation of microorganisms living in the reservoir and in them, serves as a nutrient medium for them, which leads to the formation of gases - CO2, SS and microbial surfactants, which contribute to increased oil recovery. As a result of applying the method, oil recovery reaches 81.1%, an increase in the average daily oil production rate is 504-518%. In pilot tests using this method, the oil flow in a number of wells steadily increased by 1-3 times, the total daily oil production - from 8.0 to 14.5 tons. 5 tab. Yo

Description

The invention relates to the technology of mining, in particular to methods of enhanced oil recovery, and can be used in secondary oil production.

The purpose of the invention is to increase the efficiency, simplify and reduce the cost of oil recovery.

The invention consists in the generation in the reservoir of the waste products of microorganisms — C02 and CH2 by pumping sewage sludge from the lactic acid production (SMP) into the reservoir.

organic substrate for microorganisms living in the oil reservoir, in the amount of 5-15% of the volume of produced water,

Table 1 shows the composition and properties of the SMP.

Laboratory studies have shown that the organic components of wastewater serve as a substrate for some groups of reservoir microorganisms and activate their viability (Table 1). This leads to the formation of bio-surfactants, gases, which can alter the rheological properties of reservoir fluids. Role of biopav

ABOUT

after that

GJ CO VI

volatile and non-volatile fatty acids that form soluble oxidized organic compounds also play.

Table 2 shows the growth of reservoir microflora in the SMP.

Wastewater from the lactic acid production does not clog the reservoir due to the absence of suspended particles and mechanical impurities and, at the same time, has a sufficiently large variety of organic substances to activate the formation's own microorganisms, mainly responsible for the formation of gases. In addition, microflora is naturally present in wastewater, and is also capable of generating gases. Table 3 shows the qualitative and quantitative composition of the microflora of the mixture of wastewater from lactic acid production and produced water.

In addition, sugar-lactose is the main organic component in the SMP, and in the process of microbiological processes the main components of the gas phase are C02 and CG (Table 2).

For example, 50 ml of sand mixed with oil are placed in 400 ml volumetric glasses. A mixture of formation water and wastewater is poured into the bottom of the glasses (70 and 230 ml, respectively). Glasses kept in a thermostat at 28-30 ° C in the dark.

Table 4 shows the process parameters and the results of the experiment on oil displacement in a model experiment.

From Table 4 it can be seen that the method allows to displace an average of 73.3% of oil from a porous medium.

PRI mme R 2. The experiment was carried out in models of the formation — metal columns.

Table 5 lists the parameters of the columns and the results of studying the effect of SMP on oil recovery.

As a biocenosis of gas-generating microorganisms, microorganisms isolated from the Upsheron reservoir waters of the following genera are used: Clostrldlum Lactobacillus, Desulfovlbrto, Methanobacterlum, Methanococcus, Methanosarcina, Bacillus.

Microorganisms are introduced into the columns in an amount of 10 -105 l / ml. Waste water is used as a substrate. All experiments were performed in triplicate.

The largest growth of microorganisms is observed when the concentration of wastewater is 5-15% of the volume of water in the model, which is consistent with the experience of microbiological practice, where the addition of organic substrates for cultivation of microorganisms amounts to 1-15% of the volume of media.

The results presented in Table 5 show that an increase in the average daily oil production rate occurs when the SMP is introduced at a concentration of at least 5% of the volume of water in the model. When the concentration of SMP is more than 15%, there is no increase in production rate.

At the same time, maximum oil recovery is observed within these limits. Consequently, concentrations of SMP in the range of 5-15% are economically viable. Along with evolved gas in the medium

Determine the amount of soluble oxidized compounds that can play the role of biopAV. Thus, an average of 12.6-29.5 mg / ml of soluble oxidized substances is contained in the fluid at the outlet of the columns;

including 40-85.8 mmol per 1 ml of a mixture of volatile fatty acids. As a result of the complex effect, carbonated fluids displace additional quantities of oil from reservoir models.

PRI me R 3. In the Fatmai section of the oil field of the Binagadi NGDU, Kirovneft and Azneft Production Unit, pilot tests were carried out using this method. 777 and 550 tons of wastewater are pumped into two injection wells, respectively, for 8 months. As a result of injection, after 1.5-2 months, positive effects are observed:

in eleven out of eighteen producing wells, the flow of oil steadily increased by 1-3 times;

in six of the positively reacting wells, the production water cut is significantly reduced up to

transition to the production of anhydrous oil:

in the zone of influence, there is a rise in the static and dynamic level with unchanged parameters of the downhole pump

installations:

in four wells, annular gas appears and is significantly activated. in the composition of which is fixed up to 3.0-18.0% of C02. As a result of field tests

total daily oil production increases from 8.0 to 14.5 tons. By now, more than 1.5 thousand tons of oil have been additionally produced.

Claims (1)

Claims of the method of enhanced oil recovery in secondary oil production involving the introduction of an organic substrate into the oil reservoir, characterized in that, in order to increase efficiency, simplify and reduce the cost of the process, lactic acid production wastewater is used as an organic substrate, soil in the amount of 5-15% of the volume of produced water. Table 1 Composition and properties of milk production wastewater ear substances,% including: Total nitrogen, g / l Ammonium nitrogen, g / l Lactose, g / l Glucose, g / l Galactose, g / l Lactate, mmol / l Acetate, mmol / l Propionate, mmol / l Density, N / m Viscosity, Pa-s -1SG Acidity, ° T PH avian density of 1% of the p-ra, unit.opt.pl. v3 Notes. NOM - oil-oxidizing microorganisms, GOM-gas-forming microorganisms, AC% change in the amount of soluble organic compounds, including fatty acids, alcohols, etc. Content of components after: th 1.7-3.0 0.5-1.2 0.4-2.4 9.0-16.1 2.0-7.2 0.7-2.3 17.5-42,6 5.4-7.2 0.9-3.1 1000-1015 1.18-1.32 35-50 4.6-6.2 0,081-0,087 table 2 Table 3 Note. The end of fermentation is determined by pressure & models x, SMP - drains of lactic acid production, Table 4 Table 5 termination of growth