CN116218500A

CN116218500A - Oil displacement system for high-freezing-point oil reservoir and preparation method thereof

Info

Publication number: CN116218500A
Application number: CN202111479021.2A
Authority: CN
Inventors: 肖传敏; 杨灿; 郭斐; 马静; 李晓风; 赵晔; 张艳娟; 郭丽娜; 战洪浩; 侯力嘉; 朱晓楠; 张莺; 雷东; 滕倩
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2021-12-06
Filing date: 2021-12-06
Publication date: 2023-06-06

Abstract

The application relates to the technical field of oil exploitation, in particular to an oil displacement system for a high-freezing oil reservoir, a preparation method and application thereof, wherein the oil displacement system comprises: a microbial oil displacement system and a weak base ternary oil displacement system; the microbial oil displacement system comprises: hydrocarbon degradation emulsifying bacteria, hydrocarbon degradation surface active bacteria and the balance of nutrition activating agent and water; the weak base ternary oil displacement system comprises: anionic surfactant, polymer, sodium carbonate and the balance of water; the method comprises the following steps: obtaining different strains; obtaining weak base ternary oil displacement systems with different concentrations; respectively adding different strains into the weak base ternary composite system for culture and a first single factor experiment to obtain an optimal weak base ternary oil displacement system; obtaining different microbial oil displacement systems; adding the microbial oil displacement system into the optimal weak base ternary oil displacement system for culture and a second single factor experiment to obtain the optimal microbial oil displacement system; and obtaining the stable oil displacement system according to the optimal weak base ternary oil displacement system and the optimal microorganism oil displacement system.

Description

Oil displacement system for high-freezing-point oil reservoir and preparation method thereof

Technical Field

The application relates to the technical field of petroleum exploitation, in particular to an oil displacement system for a high-freezing-point oil reservoir and a preparation method thereof.

Background

Because the oil product of high congealing oil is special in nature, is the characteristic of "freezing point is high, the wax content is high, wax precipitation temperature is high", and mobility is poor, and the exploitation degree of difficulty is lower congeals oily big, however along with oil exploitation goes on, there is a large amount of high congeals oily storage in the oil field bed at present, though accessible weak base ternary complex drives reaches the oil increasing effect, but is difficult to reduce the freezing point and the viscosity of high congeals oily, can't prevent the cold injury that high congeals oily reservoir and forms because of stratum temperature reduces in the displacement process.

Although experiments of microbial oil displacement are carried out on various large oil fields to solve the problem that the freezing point and viscosity of high-freezing oil cannot be reduced by single weak base ternary complex flooding, the viscosity of an oil displacement system is increased by adding microorganisms, and meanwhile, the activity of microorganisms is influenced by the weak base ternary complex flooding which contains various chemical reagents, so that a stable oil displacement system with proper concentration is screened out, and the technical problem to be solved is urgently needed at present.

Disclosure of Invention

The application provides an oil displacement system for a high-freezing-point oil reservoir and a preparation method thereof, which are used for solving the technical problem that a stable oil displacement system with proper concentration is difficult to screen out in the prior art.

In a first aspect, the present application provides an oil displacement system for a high pour point oil reservoir, the oil displacement system comprising: a microbial oil displacement system and a weak base ternary oil displacement system;

the microbial oil displacement system comprises the following components in percentage by mass: hydrocarbon degrading emulsifying bacteria: 0.4% -1%, hydrocarbon degradation to produce surface active bacteria: 0.4% -1%, and the balance is nutrition activator and water;

the weak base ternary oil displacement system comprises the following components in percentage by mass: anionic surfactant: 0.2 to 0.6 percent of polymer: 0.1 to 0.3 percent of sodium carbonate: 0.1 to 0.3 percent and the balance of water;

wherein the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria are obtained by culturing and screening a weak base ternary oil displacement system.

Optionally, the nutritional activator comprises, in mass fraction: microbial activator: 0.1% -0.4%, nitrogen source: 0.1 to 0.3 percent of yeast powder: 0.03 to 0.1 percent and the balance of water.

Optionally, the microbial activator comprises at least one of molasses, corn steep liquor dry powder, liquid paraffin and soybean oil, and the nitrogen source comprises at least one of sodium nitrate, ammonium chloride, urea and diammonium phosphate.

Optionally, the mass concentration of the hydrocarbon degradation emulsifying bacteria is 4700 mg/L-5000 mg/L, the mass concentration of the hydrocarbon degradation surface active bacteria is 4700 mg/L-5000 mg/L, the mass concentration of the anionic surfactant is 700 mg/L-2500 mg/L, the mass concentration of the polymer is 1200 mg/L-1500 mg/L, and the mass concentration of the sodium carbonate is 1000 mg/L-3000 mg/L.

Alternatively, the anionic surfactant is a petroleum sulfonate surfactant and the polymer is a partially hydrolyzed polyacrylamide.

In a second aspect, the present application provides a method for preparing an oil displacement system for a high pour point oil reservoir, the method comprising:

respectively obtaining hydrocarbon degradation emulsifying bacteria and hydrocarbon degradation surface active bacteria of different strains;

obtaining weak base ternary oil displacement systems with different concentrations;

respectively adding the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains into the weak base ternary composite system for culture and a first single factor experiment to obtain an optimal weak base ternary oil displacement system;

obtaining the microbial oil displacement systems with different concentrations and strains;

adding the microbial oil displacement system into the optimal weak base ternary oil displacement system for culture and a second single factor experiment to obtain the optimal microbial oil displacement system;

obtaining a stable oil displacement system according to the optimal weak base ternary oil displacement system and the optimal microbial oil displacement system;

the judgment standard of the first single-factor experiment is the change of the number of the thalli, and the judgment standard of the second single-factor experiment is the surface tension and the viscosity of the culture solution.

Optionally, the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains are respectively added into the weak base ternary composite system for culture and a first single factor experiment to obtain an optimal weak base ternary oil displacement system, which specifically comprises:

obtaining a standard weak base ternary oil displacement system;

respectively adding the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains into the standard weak base ternary oil displacement system for culturing, and then carrying out bacterial count statistics and comparison to obtain a first bacterial quantity change rate of the weak base ternary oil displacement system on the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria;

obtaining a standard nutrition activator;

mixing the standard weak base ternary oil displacement system with the standard nutritional activator to obtain a first mixed solution;

respectively adding the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains into the first mixed solution for culturing, and then carrying out bacterial count statistics and comparison to obtain the second bacterial quantity change rate of the weak base ternary oil displacement system to the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria under the condition of a nutrition activator;

Respectively adding an anionic surfactant, a polymer and sodium carbonate of the standard weak base ternary oil displacement system into the standard nutritional activator to respectively obtain a test solution of the anionic surfactant, a test solution of the polymer and a test solution of the sodium carbonate;

respectively adding the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains into the test liquid of the anionic surfactant, the test liquid of the polymer and the test liquid of the sodium carbonate for respectively culturing, and then carrying out bacterial count statistics and comparison to obtain the third bacterial quantity change rate of the weak base ternary displacement system to the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria under the condition of a nutrition activator;

and obtaining the optimal weak base ternary oil displacement system according to the first thallus quantity change rate, the second thallus quantity change rate and the third thallus quantity change rate.

Optionally, the obtaining the optimal weak base ternary oil displacement system according to the first thallus quantity change rate, the second thallus quantity change rate and the third thallus quantity change rate specifically includes:

judging whether a weak base ternary oil displacement system has an influence on the microbial oil displacement system according to the quantity change rate of the first thalli, the quantity change rate of the second thalli and the quantity change rate of the third thalli;

If yes, screening according to the first thallus quantity change rate, the second thallus quantity change rate and the third thallus quantity change rate to obtain an optimal weak base ternary oil displacement system;

if not, determining the optimal weak base ternary displacement system according to the change conditions of the first thallus quantity change rate, the second thallus quantity change rate and the third thallus quantity change rate.

Optionally, the adding the microbial oil displacement system into the optimal weak base ternary oil displacement system for culture and a second single factor experiment to obtain the optimal microbial oil displacement system, which specifically comprises the following steps:

dividing the microbial oil displacement system into microbial strains and nutrition activating agents;

respectively adding different concentrations of nutrition activators into the optimal weak base ternary oil displacement system to obtain a plurality of groups of first mixed liquid;

performing first oscillation and first measurement on a plurality of groups of first mixed liquid to respectively obtain a first surface tension change rate and a first viscosity change rate of the mixed liquid;

obtaining the nutrition activator with optimal concentration according to the first surface tension change rate and the first viscosity change rate;

mixing the hydrocarbon degradation emulsifying bacteria of different strains, the hydrocarbon degradation surface active bacteria of different strains and the nutritional activator with optimal concentration, and adding the mixture into the optimal weak base ternary oil displacement system to obtain a plurality of groups of second mixed liquid;

Performing second oscillation and second measurement on a plurality of groups of second mixed liquid to respectively obtain a second surface tension change rate and a second viscosity change rate of the second mixed liquid;

obtaining the optimal strains of the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface-active bacteria respectively according to the second surface tension change rate and the second viscosity change rate;

obtaining the optimal microbial oil displacement system according to the hydrocarbon degradation emulsifying bacteria of the optimal strain, the hydrocarbon degradation surface active bacteria of the optimal strain and the nutritional activator with the optimal concentration.

Optionally, the first measurement timing is sequentially the first day of the first oscillation, the fourth day of the first oscillation, the tenth day of the first oscillation, the fifteenth day of the first oscillation, and the thirty th day of the first oscillation.

Optionally, the temperature of the first oscillation is 55-65 ℃, and the rotating speed of the first oscillation is 160-200 r/mm.

Optionally, the second measurement timing is sequentially the first day of the second oscillation, the fourth day of the second oscillation, the tenth day of the second oscillation, the fifteenth day of the second oscillation, and the thirty th day of the second oscillation.

Optionally, the temperature of the second oscillation is 65-75 ℃, and the rotating speed of the second oscillation is 160-200 r/min.

Optionally, the hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surface active bacteria respectively obtaining different strains specifically include:

obtaining microorganisms of the oil well produced liquid;

and culturing and screening the microorganisms by adopting an emulsifying bacteria screening culture medium and a surfactant-producing bacteria culture medium respectively to obtain hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surfactant-producing bacteria of different strains.

Compared with the prior art, the technical scheme provided by the embodiment of the application has the following advantages:

according to the oil displacement system for the high-freezing-point oil reservoir, hydrocarbon degradation emulsifying bacteria and hydrocarbon degradation surface active bacteria which are cultured and screened by the weak base ternary oil displacement system are adopted in the microbial oil displacement system, after the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria are propagated in the oil displacement system, the viscosity and the surface tension of the weak base ternary oil displacement system can be improved by fermentation components of the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria, and meanwhile mass fractions of all substances in the microbial oil displacement system and the weak base ternary oil displacement system are controlled, so that on the basis that all substances in the oil displacement system are fully mixed, due to the fact that the anionic surfactant in the weak base ternary oil displacement system, the emulsifying products produced by the degradation emulsifying bacteria in the hydrocarbon microbial oil displacement system and the surface active components produced by the hydrocarbon degradation surface active bacteria are fully diffused, all substances in the oil displacement system are fully diffused through the anionic surfactant and the surface active components, and meanwhile, the viscosity added by the microbial system is fully reduced, and therefore the balanced and stable oil displacement system is obtained, and the proper concentration and stable oil displacement system is obtained.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the invention or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, and it will be obvious to a person skilled in the art that other drawings can be obtained from these drawings without inventive effort.

FIG. 1 is a schematic flow chart of a preparation method according to an embodiment of the present application;

FIG. 2 is a detailed schematic flow chart of the preparation method provided in the embodiment of the present application;

FIG. 3 is a continuation of FIG. 2;

FIG. 4 is a graph of data results of viscosity of different concentrations of nutritional activators provided in the examples herein in a weak base ternary displacement system;

FIG. 5 is a graph of data results of surface tension of different concentrations of nutritional activators provided in the examples herein in a weak base ternary displacement system;

FIG. 6 is a graph showing the results of viscosity data of hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surface active bacteria of different strains in a weak base ternary displacement system provided in the examples of the present application.

Detailed Description

For the purposes of making the objects, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present application based on the embodiments herein.

In one embodiment of the present application, there is provided a flooding system for a high pour point oil reservoir, the flooding system comprising: a microbial oil displacement system and a weak base ternary oil displacement system;

In the application, the mass fraction of the hydrocarbon degrading emulsifying bacteria is 0.4% -1%, and the hydrocarbon degrading emulsifying bacteria can fully act on the high-freezing oil within the mass fraction range, so that the viscosity of the high-freezing oil is reduced, the freezing point of the high-freezing oil is reduced, and the fluidity of the high-freezing oil is improved; when the value of the mass fraction is larger than the maximum value of the end point of the range, the adverse effect caused by the excessive addition of hydrocarbon degrading emulsifying bacteria is that the emulsified product is increased, the overall viscosity of the oil displacement system is reduced too much, the use of the oil displacement system is affected, and when the value of the mass fraction is smaller than the minimum value of the end point of the range, the adverse effect caused by the insufficient addition of hydrocarbon degrading emulsifying bacteria is that the effect of reducing the viscosity of the microbial oil displacement system is not obvious.

The mass fraction of the hydrocarbon degradation surface active bacteria is 0.4% -1%, and the active bacteria can fully act on the high-freezing-point oil within the mass fraction range, so that the surface tension of the high-freezing-point oil is reduced, and the fluidity of the high-freezing-point oil and the mixing degree between a microbial oil displacement system and a weak base ternary oil displacement system are improved; when the value of the mass fraction is larger than the maximum value of the end point of the range, the adverse effect caused by the excessive addition of the hydrocarbon degradation surface active bacteria is that the surface active components are increased, the overall surface tension of the oil displacement system is reduced too much, the fluidity of the oil displacement system in the use process is affected, and when the value of the mass fraction is smaller than the minimum value of the end point of the range, the adverse effect caused by the insufficient addition of the hydrocarbon degradation surface active bacteria is that the effect of reducing the surface tension of the microbial oil displacement system is not obvious.

The anionic surfactant has the positive effects that the anionic surfactant can fully reduce the surface tension of the high-freezing point oil within the mass fraction range, and can cooperate with a microbial oil displacement system to cooperatively reduce the surface tension of the high-freezing point oil; when the value of the mass fraction is smaller than the minimum value of the end point of the range, the negative effect is that the addition of the anionic surfactant is too small, and the weak base ternary oil displacement system cannot be fully diffused in the high-condensate oil and cannot be uniformly mixed with the microbial oil displacement system.

The mass fraction of the polymer is 0.1-0.3%, and the positive effects are that the weak base ternary oil displacement system can be fully ensured within the mass fraction range, the difficulty of petroleum to be extracted is reduced, and the extraction efficiency is improved; when the value of the mass fraction is larger than the maximum value of the end point of the range, the adverse effect caused by the excessively high content of the polymer can cause the inhibition of the microbial oil displacement system in the oil exploitation process, and when the value of the mass fraction is smaller than the minimum value of the end point of the range, the adverse effect caused by the insufficient content of the polymer can not effectively utilize the weak base ternary oil displacement system to reduce the difficulty of oil exploitation.

The sodium carbonate has the positive effects that the pH value of the weak base ternary oil displacement system can be ensured within the mass fraction range, so that the weak base ternary oil displacement system is promoted to reduce the difficulty of petroleum exploitation; when the value of the mass fraction is smaller than the minimum value of the end point of the range, the content of the sodium carbonate is too low, the normal operation of the weak base ternary oil displacement system cannot be ensured, and the reduction of the oil exploitation difficulty of the oil displacement system cannot be effectively ensured.

In some alternative embodiments, the nutritional activator comprises, in mass fractions: microbial activator: 0.1% -0.4%, nitrogen source: 0.1 to 0.3 percent of yeast powder: 0.03 to 0.1 percent and the balance of water.

In the application, the mass fraction of the microbial activator is 0.1-0.4%, and the microbial activator has the positive effects that the microbial activator can fully activate microorganisms and provide carbon sources required by the propagation of the microorganisms within the mass fraction range; when the value of the mass fraction is larger than the maximum value of the end point of the range, the adverse effect is caused by that the carbon source in the microorganism contains mostly small sugar after decomposition or hydrolysis, the viscosity of the microorganism oil displacement system is increased, so that the overall viscosity of the oil displacement system is increased, the use of the oil displacement system is affected, and when the value of the mass fraction is smaller than the minimum value of the end point of the range, the adverse effect is caused by that the content of the microorganism activator is insufficient and the microorganism cannot effectively reproduce.

The mass fraction of the nitrogen source is 0.1-0.3%, and the positive effects are that in the mass fraction range, the nitrogen source required by microorganism propagation can be provided, and meanwhile, the pH value of a microorganism oil displacement system can be adjusted by part of the nitrogen source, so that the oil displacement system is more suitable for microorganism propagation; when the value of the mass fraction is larger than the maximum value of the end point of the range, the adverse effect caused by the excessively high nitrogen source is waste, meanwhile, the pH value of the partial nitrogen source on the microbial oil displacement system is excessively adjusted to influence the stability of the microbial oil displacement system, and when the value of the mass fraction is smaller than the minimum value of the end point of the range, sufficient nitrogen source cannot be provided for the microorganisms, and the growth and the propagation of the microorganisms are influenced.

The yeast powder has the positive effects that in the mass fraction range, the yeast contained in the yeast powder can serve as a nutritional supplement, so that the propagation of corresponding hydrocarbon degradation emulsifying bacteria and hydrocarbon degradation surface active bacteria can be effectively promoted, the biological activities of the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria in a microbial oil displacement system are improved, and the difficulty of petroleum exploitation is further reduced; when the value of the mass fraction is smaller than the minimum value of the end point of the range, the adverse effect caused by too low content of the yeast powder cannot effectively promote the propagation of hydrocarbon degradation emulsifying bacteria and hydrocarbon degradation surfactant bacteria, so that the microbial oil displacement system cannot effectively reduce the difficulty of petroleum exploitation.

In some alternative embodiments, the microbial activator comprises at least one of molasses, corn steep liquor dry powder, liquid paraffin, and soybean oil, and the nitrogen source comprises at least one of sodium nitrate, ammonium chloride, urea, and diammonium phosphate.

In the application, the microbial activator comprises at least one of molasses, corn steep liquor dry powder, liquid paraffin and soybean oil, and has the positive effects of adopting a conventional low-cost culture medium as a carbon source and saving exploitation cost.

The positive effect of the nitrogen source comprising at least one of sodium nitrate, ammonium chloride, urea and diammonium phosphate is that the conventional nitrogen source is adopted, so that the exploitation cost is saved.

As an alternative embodiment, the mass concentration of the hydrocarbon degradation emulsifying bacteria is 4700mg/L to 5000mg/L, the mass concentration of the hydrocarbon degradation surface active bacteria is 4700mg/L to 5000mg/L, the mass concentration of the anionic surfactant is 700mg/L to 2500mg/L, the mass concentration of the polymer is 1200mg/L to 1500mg/L, and the mass concentration of the sodium carbonate is 1000mg/L to 3000mg/L.

In the application, the mass concentration of the hydrocarbon degrading emulsifying bacteria is 4700 mg/L-5000 mg/L, and the hydrocarbon degrading emulsifying bacteria can effectively degrade and emulsify part of difficult-to-extract petroleum within the concentration range; when the value of the mass concentration is smaller than the minimum value of the end point of the range, the adverse effect caused by insufficient hydrocarbon degradation emulsifying bacteria cannot be effectively emulsified by difficult petroleum exploitation, so that the difficulty of petroleum exploitation cannot be effectively reduced.

The mass concentration of the hydrocarbon degradation surface active bacteria is 4700 mg/L-5000 mg/L, and the active effect is that in the concentration range, hydrocarbon degradation emulsifying bacteria can effectively degrade and increase the surface activity of difficult-to-extract oil, thereby promoting the transmission of difficult-to-extract oil; when the value of the mass concentration is smaller than the minimum value of the end point of the range, the adverse effect caused by insufficient surface active bacteria produced by hydrocarbon degradation cannot effectively enhance the surface activity of difficult-to-extract petroleum, so that the difficulty of petroleum extraction cannot be effectively reduced.

The mass concentration of the anionic surfactant is 700 mg/L-2500 mg/L, and the anionic surfactant can be used for increasing the partial surface activity of difficult-to-recover petroleum in the concentration range, so that the propagation of hydrocarbon degradation surface active bacteria on the petroleum after surface activation in a microbial oil displacement system is promoted, the surface activity of the difficult-to-recover petroleum is further enhanced, and the recovery of the difficult-to-recover petroleum is promoted; when the value of the mass concentration is larger than the maximum value of the end point of the range, the negative effect caused by the mass concentration is that the anionic surfactant can inhibit the propagation of strains in the microbial oil displacement system, so that the whole exploitation difficulty of the oil displacement system is increased by too much anionic surfactant, and when the value of the mass concentration is smaller than the minimum value of the end point of the range, the negative effect caused by the mass concentration is that the anionic surfactant is insufficient, the propagation of hydrocarbon degradation surface active bacteria in the microbial oil displacement system on the petroleum after surface activation can not be promoted, and the exploitation difficulty of the petroleum is increased.

The mass concentration of the polymer is 1200 mg/L-1500 mg/L, and the active effect of the polymer is that in the concentration range, the polymer can effectively promote the viscosity increase of difficult-to-recover petroleum, thereby promoting the mutual reaction among various substances, and further promoting the emulsification of hydrocarbon degradation emulsifying bacteria on the difficult-to-recover petroleum, and further promoting the recovery of difficult-to-recover petroleum by an oil displacement system; when the value of the mass concentration is smaller than the minimum value of the end point of the range, the adverse effect is insufficient in polymer content, and emulsification of hydrocarbon degrading emulsifying bacteria on difficult-to-mine petroleum cannot be promoted, so that the exploitation difficulty of petroleum is increased.

The mass concentration of the sodium carbonate is 1000 mg/L-3000 mg/L, and the alkaline sodium carbonate can ensure the pH value of the weak base ternary oil displacement system in the concentration range, so that the weak base ternary oil displacement system is promoted to reduce the difficulty of petroleum exploitation; when the value of the mass concentration is smaller than the minimum value of the end point of the range, the content of the sodium carbonate is too low, the normal operation of the weak base ternary oil displacement system cannot be ensured, and the reduction of the oil exploitation difficulty of the oil displacement system cannot be effectively ensured.

In some alternative embodiments, the anionic surfactant is a petroleum sulfonate surfactant and the polymer is a partially hydrolyzed polyacrylamide, wherein the partially hydrolyzed polyacrylamide is prepared by (partially hydrolyzed polyacrylamide is from elsen (china) flocculant limited, molecular weight 1900-2200 tens of thousands, degree of hydrolysis 23% -27%).

In the application, the anionic surfactant is petroleum sulfonate surfactant, so that the surface tension of an oil displacement system can be sufficiently reduced, the oil displacement system is economical and easy to obtain, and the exploitation cost is reduced.

The polymer is partially hydrolyzed polyacrylamide, and has the positive effects that the partially hydrolyzed polyacrylamide is dissociated into negatively charged macromolecules after being dissolved in water, and the intermolecular electrostatic repulsion and the anionic repulsive force between different chain units on the same molecule lead the molecules to stretch in the solution and enable the molecules to intertwine, so that the viscosity of petroleum in production is increased, the subsequent effects of hydrocarbon degradation emulsifying bacteria, hydrocarbon degradation surfactant and anionic surfactant on petroleum difficult to produce are facilitated, and the difficulty of petroleum production is reduced.

In one embodiment of the present application, a method for preparing an oil displacement system for a high pour point oil reservoir is provided, the method comprising:

S1, respectively obtaining hydrocarbon degradation emulsifying bacteria and hydrocarbon degradation surface active bacteria of different strains;

s2, obtaining weak base ternary oil displacement systems with different concentrations;

s3, respectively adding the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains into the weak base ternary composite system for culture and a first single factor experiment to obtain an optimal weak base ternary oil displacement system;

s4, obtaining microorganism oil displacement systems with different concentrations and strains;

s5, adding the microbial oil displacement system into the optimal weak base ternary oil displacement system for culture and a second single factor experiment to obtain the optimal microbial oil displacement system;

s6, obtaining a stable oil displacement system according to the optimal weak base ternary oil displacement system and the optimal microbial oil displacement system;

In the application, the optimal concentration of the weak base ternary oil displacement system is determined, and then the microbial oil displacement system is reversely screened by the determined weak base ternary oil displacement system, so that the determined weak base ternary oil displacement system and the determined microbial oil displacement system can be obtained, and further the stable oil displacement system and the oil displacement system with proper concentration are obtained.

In some optional embodiments, the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains are added into the weak base ternary complex system to perform culture and a first single factor experiment, so as to obtain an optimal weak base ternary oil displacement system, which specifically comprises:

s31, obtaining a standard weak base ternary oil displacement system;

s32, respectively adding the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains into the standard weak base ternary oil displacement system for culturing, and then carrying out bacterial count statistics and comparison to obtain a first bacterial quantity change rate of the weak base ternary oil displacement system on the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria;

s33, obtaining a standard nutrition activator;

s34, mixing the standard weak base ternary oil displacement system with the standard nutritional activator to obtain a first mixed solution;

s35, respectively adding the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains into the first mixed solution for culturing, and then carrying out bacterial count statistics and comparison to obtain a second bacterial quantity change rate of a weak base ternary oil displacement system on the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria under the condition of a nutrition activator;

S36, respectively adding the anionic surfactant, the polymer and the sodium carbonate of the standard weak base ternary oil displacement system into the standard nutritional activator to respectively obtain a test solution of the anionic surfactant, a test solution of the polymer and a test solution of the sodium carbonate;

s37, respectively adding the hydrocarbon degradation emulsifying bacteria of different strains and the hydrocarbon degradation surface active bacteria of different strains into the test solution of the anionic surfactant, the test solution of the polymer and the test solution of the sodium carbonate for culture, and then carrying out bacterial count statistics and comparison to obtain the third bacterial quantity change rate of the weak base ternary oil displacement system on the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria under the condition of a nutrition activator;

s38, obtaining the optimal weak base ternary oil displacement system according to the first thallus quantity change rate, the second thallus quantity change rate and the third thallus quantity change rate.

In some optional embodiments, the obtaining an optimal weak base ternary flooding system according to the first thallus quantity change rate, the second thallus quantity change rate and the third thallus quantity change rate specifically includes:

S381, judging whether a weak base ternary oil displacement system has an influence on the microbial oil displacement system according to the first thallus quantity change rate, the second thallus quantity change rate and the third thallus quantity change rate;

In the application, the influence of the strain in the microbial oil displacement system in the weak base ternary oil displacement system is shown in a data mode by taking the number of thalli in the microbial oil displacement system as a judgment standard, so that a quantization standard is provided for screening out a proper weak base ternary oil displacement system.

In some alternative embodiments, the adding the microbial flooding system to the optimal weak base ternary flooding system is performed for culture and a second single factor experiment, so as to obtain the optimal microbial flooding system, which specifically comprises:

S51, dividing the microbial oil displacement system into microbial strains and nutritional activators;

s52, respectively adding nutrition activators with different concentrations into the optimal weak base ternary oil displacement system to obtain a plurality of groups of first mixed liquid;

s53, carrying out first oscillation and first measurement on a plurality of groups of first mixed liquid to respectively obtain a first surface tension change rate and a first viscosity change rate of the mixed liquid;

s54, obtaining the optimal concentration of the nutrition activator according to the first surface tension change rate and the first viscosity change rate;

s55, respectively obtaining hydrocarbon degradation emulsifying bacteria and hydrocarbon degradation surface active bacteria of different strains;

s56, respectively mixing the hydrocarbon degradation emulsifying bacteria of different strains, the hydrocarbon degradation surface active bacteria of different strains and the nutritional activator with optimal concentration, and then adding the mixture into the optimal weak base ternary oil displacement system to obtain a plurality of groups of second mixed liquid;

s57, carrying out second oscillation and second measurement on a plurality of groups of second mixed liquid to respectively obtain a second surface tension change rate and a second viscosity change rate of the second mixed liquid;

s58, respectively obtaining the optimal strains of the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria according to the second surface tension change rate and the second viscosity change rate;

S59, obtaining the optimal microorganism oil displacement system according to the hydrocarbon degradation emulsifying bacteria of the optimal strain, the hydrocarbon degradation surface active bacteria of the optimal strain and the nutritional activator with optimal concentration.

In the application, the concentration of the nutrition activator is screened through the optimal weak base ternary oil displacement system, and meanwhile, the hydrocarbon degradation emulsifying bacteria and the strains of the hydrocarbon degradation surface active bacteria are cultured and screened, so that the microbial oil displacement system with small influence on the viscosity and the surface tension of the optimal weak base ternary oil displacement system can be obtained.

As an alternative embodiment, the first measurement is performed on the first day of the first oscillation, the fourth day of the first oscillation, the tenth day of the first oscillation, the fifteenth day of the first oscillation, and the thirty th day of the first oscillation in this order;

the temperature of the first oscillation is 55-65 ℃, and the rotating speed of the first oscillation is 160-200 r/min.

In the application, the first determination time is limited, so that the nutritional activator and the optimal weak base ternary oil displacement system are convenient to mix uniformly, and the influence of the addition of the nutritional activator on the viscosity and the surface tension of the optimal weak base ternary oil displacement system can be determined.

The first oscillation temperature is 55-65 ℃, and the positive effect is that in the temperature range, the exploitation environment of the high-freezing oil can be accurately simulated, so that the influence of the nutrition activator on the viscosity and the surface tension of the optimal weak base ternary oil displacement system can be obtained; when the value of the temperature is larger than the maximum value of the end point of the range, the adverse effect is that the too high temperature causes the solubility change of the nutrition activator, the exploitation environment cannot be accurately simulated, and when the value of the temperature is smaller than the minimum value of the end point of the range, the adverse effect is that the too low temperature causes the nutrition activator to be insufficiently dissolved in the optimal weak base ternary oil displacement system, and the detection result is inaccurate.

The positive effect of the first oscillation with the rotating speed of 160 r/min-200 r/min is that under the rotating speed condition, the nutrition activator and the optimal weak base ternary oil displacement system can be fully and uniformly mixed; when the value of the rotating speed is smaller than the minimum value of the end point of the range, the adverse effect is insufficient mixing between the nutrition activating agent and the optimal weak base ternary displacement system, the result of the first measurement is influenced, and the optimal concentration of the nutrition activating agent cannot be accurately obtained.

As an alternative embodiment, the second measurement is performed on the first day of the second oscillation, the fourth day of the second oscillation, the tenth day of the second oscillation, the fifteenth day of the second oscillation, and the thirty th day of the second oscillation in this order;

the temperature of the second oscillation is 65-75 ℃, and the rotating speed of the second oscillation is 160-200 r/min.

In this application, inject the opportunity of second survey to make things convenient for microorganism oil displacement system and weak base ternary oil displacement system misce bene, and then can survey the effect of the addition of the microorganism oil displacement system of different bacterial to the viscosity and the surface tension of the weak base ternary oil displacement system of the best.

The positive effect of the second oscillation temperature of 65-75 ℃ is that in the temperature range, the exploitation environment of the high-freezing oil can be accurately simulated, so that the influence of the microbial oil displacement system on the viscosity and the surface tension of the weak base ternary oil displacement system can be obtained; when the value of the temperature is smaller than the minimum value of the end point of the range, the adverse effect caused by the fact that the too low temperature can not be fully dissolved in the weak base ternary oil displacement system, and the detection result is inaccurate.

The positive effect of the second oscillation rotating speed of 160-200 r/min is that the microbial oil displacement system and the weak base ternary oil displacement system can be fully and uniformly mixed under the rotating speed condition; when the value of the rotating speed is smaller than the minimum value of the end point of the range, the adverse effect caused by insufficient mixing between the microbial oil displacement system and the weak base ternary oil displacement system is caused, the result of the second measurement is influenced, and the optimal strain of the microbial oil displacement system cannot be accurately obtained.

As an alternative embodiment, the weak base ternary flooding system comprises: petroleum sulfonate type surfactant: 0.2% -0.6%, partially hydrolyzed polyacrylamide: 0.1 to 0.3 percent of sodium carbonate: 0.1 to 0.3 percent and the balance of water.

In the application, the petroleum sulfonate surfactant with the mass fraction of 0.2-0.6 percent has the positive effects that the petroleum sulfonate surfactant in the mass fraction range can fully reduce the surface tension of the high-freezing point oil, and can cooperate with a microbial oil displacement system to cooperatively reduce the surface tension of the high-freezing point oil; when the value of the mass fraction is smaller than the minimum value of the end point of the range, the adverse effect caused by too small addition amount of the petroleum sulfonate surfactant cannot be fully diffused in the high-freezing oil, and meanwhile cannot be uniformly mixed with the microbial oil displacement system.

The mass fraction of the partially hydrolyzed polyacrylamide is 0.1-0.3%, and the positive effects are that in the mass fraction range, the polymer can effectively promote the viscosity increase of difficult-to-recover petroleum, so that the mutual reaction among various substances is promoted, the emulsification of hydrocarbon degradation emulsifying bacteria on the difficult-to-recover petroleum is promoted, and the recovery of an oil displacement system on the difficult-to-recover petroleum is further promoted; when the value of the mass fraction is smaller than the minimum value of the end point of the range, the content of the partially hydrolyzed polyacrylamide is insufficient, and emulsification of hydrocarbon degrading emulsifying bacteria on difficult-to-mine petroleum cannot be promoted, so that the petroleum exploitation difficulty is increased.

As an optional embodiment, the hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surface active bacteria respectively obtained from different strains specifically include:

s11, obtaining microorganisms of oil well produced liquid;

s12, culturing and screening the microorganisms by adopting an emulsifying bacteria screening culture medium and a surfactant-producing bacteria culture medium respectively to obtain hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surfactant-producing bacteria of different strains.

In the application, the microorganisms of the oil well produced liquid are enriched, and the emulsifying bacteria screening culture medium and the surfactant-producing bacteria culture medium are respectively utilized for culture and screening, so that the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surfactant-producing bacteria strains which can grow on the emulsifying bacteria screening culture medium and the surfactant-producing bacteria culture medium are screened out.

In one embodiment of the present application, there is provided the use of an oil displacement system for a high pour point reservoir, the oil displacement system being used for displacement recovery of high pour point oil.

Example 1

An oil displacement system for a high pour point oil reservoir comprising: a microbial oil displacement system and a weak base ternary oil displacement system;

the microbial oil displacement system comprises the following components in percentage by mass: hydrocarbon degrading emulsifying bacteria: 0.5 percent of hydrocarbon degradation surface active bacteria: 0.5%, nutritional activator: 10%, the balance being water;

the weak base ternary oil displacement system comprises the following components in percentage by mass: anionic surfactant: 0.4%, polymer: 0.2%, sodium carbonate: 0.2%, the balance being water;

wherein, hydrocarbon degradation emulsifying bacteria and hydrocarbon degradation surface active bacteria are cultivated and screened by a weak base ternary oil displacement system.

The nourishing activator comprises the following components in percentage by mass: microbial activator: 0.2%, nitrogen source: 0.2%, yeast powder: 0.05% and the balance of water.

The microbial activator is corn steep liquor dry powder, and the nitrogen source is sodium nitrate and diammonium hydrogen phosphate with the mass ratio of 1:1.

The mass concentration of the hydrocarbon degradation emulsifying bacteria is 4900mg/L, the mass concentration of the hydrocarbon degradation surface active bacteria is 4900mg/L, the mass concentration of the anionic surfactant is 1600mg/L, the mass concentration of the polymer is 1400mg/L, and the mass concentration of the sodium carbonate is 2000mg/L.

The anionic surfactant is a petroleum sulfonate surfactant and the polymer is partially hydrolyzed polyacrylamide.

As shown in fig. 2, a method for preparing an oil displacement system for a high pour point oil reservoir, the method comprising:

s11, obtaining microorganisms of oil well produced liquid;

s12, respectively culturing and screening microorganisms by adopting an emulsifying bacteria screening culture medium and a surfactant-producing bacteria culture medium to obtain hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surfactant-producing bacteria of different strains; wherein, the raw materials of the emulsified bacteria screening culture medium are as follows: 3.32g of high-setting oil, 4.0g of NH ₄ NO ₃ 4.0g of K ₂ HPO ₄ KH of 6.0g ₂ PO ₄ 0.2g of MgSO ₄ 7H2O, trace elements: 1.0g CaCl ₂ ·2H ₂ O，1.0g FeSO ₄ ·7H ₂ O,1.4g EDTA;

the surfactant-producing bacteria culture medium comprises the following raw materials: k1 g ₂ HPO ₄ KH 1g ₂ PO ₄ 0.2g of MgSO ₄ 0.05g FeCl ₃ 0.02g of CaCl ₂ 0.5g NH ₄ Cl,0.5g NaNO ₃ 1g of yeast extract, 5g of liquid paraffin, wherein the pH value of the surfactant-producing bacteria culture medium is 7.0-7.2;

the total screening results in 8 hydrocarbon degrading emulsion bacteria and 20 hydrocarbon degrading surface active bacteria.

s31, obtaining a standard weak base ternary oil displacement system;

s32, respectively adding hydrocarbon degradation emulsifying bacteria of different strains and hydrocarbon degradation surface active bacteria of different strains into a standard weak base ternary oil displacement system for culturing, and then carrying out bacterial count statistics and comparison to obtain a first bacterial quantity change rate of the weak base ternary oil displacement system on the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria;

s33, obtaining a standard nutrition activator;

s34, mixing a standard weak base ternary oil displacement system and a standard nutrition activator to obtain a first mixed solution;

s35, respectively adding hydrocarbon degradation emulsifying bacteria of different strains and hydrocarbon degradation surface active bacteria of different strains into the first mixed solution for culturing, and then carrying out bacterial count statistics and comparison to obtain the second bacterial quantity change rate of the weak base ternary oil displacement system on the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria under the condition of a nutrition activator;

S36, respectively adding an anionic surfactant, a polymer and sodium carbonate of a standard weak base ternary oil displacement system into a standard nutrition activator to respectively obtain a test solution of the anionic surfactant, a test solution of the polymer and a test solution of the sodium carbonate;

s37, respectively adding hydrocarbon degradation emulsifying bacteria of different strains and hydrocarbon degradation surface active bacteria of different strains into the test solution of the anionic surfactant, the test solution of the polymer and the test solution of sodium carbonate for culture, and then carrying out bacterial count statistics and comparison to obtain a third bacterial quantity change rate of the weak base ternary oil displacement system on the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria under the condition of a nutrition activator;

s381, judging whether the weak base ternary oil displacement system has influence on the microbial oil displacement system according to the quantity change rate of the first thalli, the quantity change rate of the second thalli and the quantity change rate of the third thalli;

if not, determining an optimal weak base ternary oil displacement system according to the change conditions of the first thallus quantity change rate, the second thallus quantity change rate and the third thallus quantity change rate;

s51, dividing a microbial oil displacement system into microbial strains and a nutrition activator;

s52, respectively adding the nutrition activators with different concentrations into the optimal weak base ternary oil displacement system to obtain a plurality of groups of first mixed liquid;

s56, respectively mixing hydrocarbon degradation emulsifying bacteria of different strains, hydrocarbon degradation surface active bacteria of different strains and nutrition activating agents with optimal concentration, and then adding the mixture into an optimal weak base ternary oil displacement system to obtain a plurality of groups of second mixed liquid;

s58, respectively obtaining optimal strains of hydrocarbon degradation emulsifying bacteria and hydrocarbon degradation surface active bacteria according to the second surface tension change rate and the second viscosity change rate;

S59, degrading the surface active bacteria and the nutritional activator with the optimal concentration according to hydrocarbon degradation emulsifying bacteria of the optimal strain to obtain an optimal microbial oil displacement system;

s6, obtaining a stable oil displacement system according to the optimal weak base ternary oil displacement system and the optimal microorganism oil displacement system;

the first single factor experiment has a judgment standard of change of the number of the thalli, and the second single factor experiment has a judgment standard of surface tension and viscosity of the culture solution.

The first measurement timing is the first day of the first oscillation, the fourth day of the first oscillation, the tenth day of the first oscillation, the fifteenth day of the first oscillation, and the thirty th day of the first oscillation in this order;

the temperature of the first oscillation is 60 ℃, and the rotating speed of the first oscillation is 180r/min.

The second measurement timing is sequentially the first day of the second oscillation, the fourth day of the second oscillation, the tenth day of the second oscillation, the fifteenth day of the second oscillation, and the thirty th day of the second oscillation;

the temperature of the second oscillation is 70 ℃, and the rotating speed of the second oscillation is 180r/min.

The weak base ternary oil displacement system comprises: petroleum sulfonate type surfactant: 0.4%, partially hydrolyzed polyacrylamide: 0.2%, sodium carbonate: 0.2% and the balance of water.

The specific operation method of the first single factor experiment comprises the following steps:

1. influence of weak base ternary displacement system on microorganisms:

1. influence of weak base ternary oil displacement system on strain:

preparing a ternary system by using sterilized deionized water to obtain a standard weak base ternary oil displacement system comprising 0.25 mass percent of polymer, 0.4 percent of surfactant and 0.2 percent of sodium carbonate, subpackaging the obtained weak base ternary oil displacement system into 5mL sterile test tubes, respectively inoculating hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surfactant according to the inoculation amount accounting for 10 percent of the total weight of the weak base ternary oil displacement system according to 2 repeated tests, oscillating and uniformly mixing, and culturing in a 70 ℃ incubator, wherein the results are shown in table 1.

TABLE 1

After 2d, the plate count was performed on each of the cultured cells, and as a result, it was found that the numbers of cells of H65-14, H65-19, H65-20, H65-22, H65-23, H65-24, H65-25, H65-26, H70-2 and H70-3 were not significantly different from those of the control group, and after 7d culture, it was found that all cells could not grow in the ternary system, and further that the viscosity of all ternary systems was not significantly reduced by qualitative observation of the viscosity change.

2. Influence of weak base ternary displacement system on microbial system:

the corn steep liquor dry powder is used as a carbon source, ammonium chloride or sodium nitrate is used as a nitrogen source, the carbon source and the nitrogen source are prepared into an activator system according to a proportion, the standard weak base ternary oil displacement system and the activator system are mixed to obtain a standard mixed solution, H65-1, H65-8, H65-19 and H70-7 are respectively inoculated in the mixed solution taking ammonium chloride as the nitrogen source according to the inoculation amount accounting for 0.5% of the total weight of the standard mixed solution, H65-3, H65-4, H65-6, H65-11, H65-13, H65-15, H65-18 and H70-2 are respectively inoculated in the mixed solution taking sodium nitrate as the nitrogen source, and the inoculated systems are placed at 70 ℃ for static culture, and the average concentration change is observed as shown in a table 2.

TABLE 2

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As is clear from Table 2, after 14d, the surface of the system in which the activator was prepared had no lumps, but had all the precipitates, and the uniformity was good, and the number of cells detected during the period of 2d to 14d after inoculation showed that: the number of cells was stable, but no apparent proliferation was seen, and the results indicated that the growth of microorganisms in the weak ternary system was inhibited in the presence of a nutritional activator.

3. Influence of monomer components in weak base ternary system on microbial system:

(1) Effects of the polymers on the microbial System:

the corn steep liquor dry powder is used as a carbon source, ammonium chloride or sodium nitrate is used as a nitrogen source, the carbon source and the nitrogen source are prepared into an activator system according to a proportion, the polymer in the standard weak base ternary oil displacement system and the activator system are mixed to obtain a standard polymer mixed solution with the mass concentration of 0.2%, H65-1, H65-8, H65-19 and H70-7 are respectively inoculated into the mixed solution taking ammonium chloride as the nitrogen source according to the inoculation amount accounting for 0.5% of the total weight of the standard polymer mixed solution, H65-3, H65-4, H65-6, H65-11, H65-13, H65-15, H65-18 and H70-2 are respectively inoculated into the mixed solution taking sodium nitrate as the nitrogen source, the inoculated systems are respectively placed under the condition of 70 ℃ for static culture, and the change of the average concentration is observed, as shown in Table 3.

TABLE 3 Table 3

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As is clear from Table 3, after 7d, the surface of the system in which the activator was prepared had no lumps, but had precipitates, but had good uniformity, and the number of cells detected during the period of 2d to 7d after inoculation showed that: the number of cells is stable and there is some proliferation, and the results indicate that microorganisms can grow in the polymer solution in the presence of a nutritional activator, but at a slow rate.

(2) Effect of surfactants on microbial systems:

the preparation method comprises the steps of taking corn steep liquor dry powder as a carbon source, taking ammonium chloride or sodium nitrate as a nitrogen source, preparing a activator system by the carbon source and the nitrogen source according to a proportion, mixing a surfactant in a standard weak base ternary oil displacement system with the activator system to obtain a standard surfactant mixed solution with the mass concentration of 0.2%, respectively inoculating H65-1, H65-8, H65-19 and H70-7 into the mixed solution taking ammonium chloride as the nitrogen source according to the inoculation amount accounting for 0.5% of the total weight of the standard surfactant mixed solution, inoculating H65-3, H65-4, H65-6, H65-11, H65-13, H65-15, H65-18 and H70-2 into the mixed solution taking sodium nitrate as the nitrogen source, respectively standing and culturing the inoculated systems at 70 ℃, and observing the change of the average concentration, wherein the mixed solution is shown in a table 4.

TABLE 4 Table 4

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As can be seen from Table 4, the number of cells was measured during 7d after inoculation, and the result showed a significant decrease in the number of cells, indicating that the microorganisms could not grow in the surfactant solution under the conditions of the nutritional activator.

(3) Alkali (Na) ₂ CO ₃ ) Effects on the microbial System:

the preparation method comprises the steps of taking corn steep liquor dry powder as a carbon source, taking ammonium chloride or sodium nitrate as a nitrogen source, preparing a activator system by mixing the carbon source and the nitrogen source according to a proportion, mixing a surfactant in a standard weak base ternary oil displacement system with the activator system to obtain a standard alkali mixed solution with the mass concentration of 0.2%, respectively inoculating H65-1, H65-8, H65-19 and H70-7 into the mixed solution taking ammonium chloride as the nitrogen source according to the inoculation amount accounting for 0.5% of the total weight of the standard alkali mixed solution, and inoculating H65-3, H65-4, H65-6, H65-11, H65-13, H65-15, H65-18 and H70-2 into the mixed solution taking sodium nitrate as the nitrogen source, respectively standing and culturing the inoculated systems at 70 ℃, and observing the change of the average concentration, wherein the mixed solution is shown in a table 5.

TABLE 5

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As is clear from Table 5, the detection of the number of cells during 7d after inoculation showed a substantial decrease in the number of cells, which suggests that microorganisms could not grow in alkaline solution under the conditions of the nutritional activator.

In conclusion, the weak base ternary oil displacement system has an inhibition effect on the microbial oil displacement system generally, so that the influence of the microbial oil displacement system on the weak base ternary oil displacement system needs to be further examined.

2. The specific operation of the second single factor experiment is as follows:

1. The specific operation method of the first measurement is as follows:

(1) Viscosity measurement operation:

preparing a weak base ternary oil displacement system according to the proportion, respectively adding 100mL of corn steep liquor dry powder (0.05%, 0.2%, 0.4%, 0.8%), sodium nitrate (0.05%, 0.2%, 0.4%, 0.8%), dipotassium hydrogen phosphate (0.05%, 0.2%, 0.4%, 0.8%) and yeast powder (0.05%, 0.2%, 0.4%, 0.8%) into a plurality of groups of equivalent weak base ternary oil displacement systems, stirring and dissolving, measuring viscosity data every 12h under the condition of first oscillation, and adding the same amount of weak base ternary oil displacement system into a control group, wherein the results are shown in Table 6.

TABLE 6

Group of	16h	24h	48h
				0.05% corn steep liquor	101.6	99.4	96.3
0.2% corn steep liquor	100.3	97.1	95.5
				0.4% corn steep liquor	29.9	26.7	24.5
0.8% corn steep liquor	30.9	27.7	25.5
				0.05% sodium nitrate	112.0	102.6	91.5
0.2% sodium nitrate	110.0	100.2	91.5
				0.4% sodium nitrate	72.5	67.9	63.4
0.8% sodium nitrate	49.1	46.5	40.1
				0.05% dipotassium hydrogen phosphate	102.4	99.1	98.7
0.2% dipotassium hydrogen phosphate	98.9	98.7	97.1
				0.4% dipotassium hydrogen phosphate	72.5	68.3	64.5
0.8% dipotassium hydrogen phosphate	52.3	47.9	45.3
				0.05% Yeast powder	92.8	91.4	91.8
0.2% Yeast powder	93.5	90.2	89.7
				0.4% Yeast powder	36.3	34.7	30.5
0.8% Yeast powder	7.47	5.33	4.74
				Compound nutrition activator	90.4	88.7	87.5
Control group	106.3	102.6	92.7

In table 6, the compounded nutritional activators were: corn steep liquor of 0.05% yeast powder, 0.2% dipotassium hydrogen phosphate, 0.2% sodium nitrate and 0.2% sodium nitrate

As can be seen from table 6 and fig. 4, the system viscosity decrease amplitude increases significantly with increasing concentration of activator factor; when the factor concentration of the single activator is only 0.2%, the viscosity of the weak base ternary oil displacement system acted by all single factors is reduced slowly, the viscosity is equivalent to the viscosity reduction speed (natural aging) of the pure weak base ternary oil displacement system, and when the factor concentration of the single activator is lower than 0.2%, the viscosity change of the compounded activator is basically consistent with that of the weak base ternary oil displacement system acted by single components of the activator; therefore, in actual use, the microbial oil displacement system can be injected first for fermentation and then the weak base ternary oil displacement system, and when the concentration residual quantity of the nutrition activator is lower than 0.2%, the viscosity of the follow-up weak base ternary oil displacement system is not affected.

(2) Surface tension operation:

preparing nutrition activator solution A:1% corn steep liquor dry powder +0.2% sodium nitrate +0.2% dipotassium hydrogen phosphate +0.05% yeast powder, nutrition activator solution B: and (3) sterilizing the solution A and the solution B by using 0.2% corn steep liquor dry powder, 0.2% ammonium chloride, 0.2% dipotassium hydrogen phosphate and 0.05% yeast powder, diluting the solution A and the solution B to different concentrations, respectively adding the solution A and the solution B with different concentrations into a weak base ternary oil displacement system, stirring and dissolving, oscillating according to a first oscillating condition, measuring the change of the surface tension value of the solution after 48 hours, and the results are shown in table 7.

TABLE 7

As can be seen from table 7 and fig. 5, the different concentrations of the nutritional activator have a lower effect on the surface tension in the weak base ternary displacement system, indicating that the total nutritional activator concentration has a lower effect on the surface tension in the weak base ternary displacement system and a greater effect on the viscosity.

2. The specific operation method of the second measurement is as follows:

(1) Viscosity measurement operation:

respectively taking 8 strains of hydrocarbon degrading emulsifying bacteria and 20 strains of hydrocarbon degrading surface active bacteria after screening, fermenting, and taking the bacteria with the concentration of 10 ⁷ -10 ⁸ The cfu/mL fresh fermentation broth is added for 5mL, centrifugation is carried out for 5min under 8000r/min, the supernatant is discarded, the thallus is added into 5mL of sterilized normal saline for eluting for 3 times, then 100mL of solution of the weak base ternary oil displacement system is added, the mixture is put into a constant temperature oscillator for second oscillation, the viscosity is detected according to the second determination time, the control group is only added with the same amount of weak base ternary oil displacement system, and the result is shown in Table 8 after bad strains are removed.

TABLE 8

Group of	1d viscosity	Viscosity at 4d	10d viscosity
				H65-1 strain group	97.8	88.6	78.6
H65-4 strain group	98.5	89.3	79.2
				H65-6 strain group	98.5	88.5	77.5
H65-8 strain group	98.7	87.6	76.8
				H65-11 strain group	98.6	87.9	77.8
H65-13 strain group	97.9	88.6	77..9
				H65-15 strain group	98.5	87.8	76.3
H65-16 strain group	98.6	89.2	78.6
				H65-18 strain group	98.7	87.6	78.9
H70-2 strain group	98.5	89.3	78.6
				Control group	98.6	89.5	78.3

As can be seen from Table 8 and FIG. 6, the simple addition of hydrocarbon degrading emulsifying bacteria or hydrocarbon degrading surfactant has little effect on the viscosity of the weak base ternary oil displacement system, and the degradation speed of the weak base ternary oil displacement system is consistent with that of the control group.

(2) Surface tension operation:

respectively taking 8 strains of hydrocarbon degrading emulsifying bacteria and 20 strains of hydrocarbon degrading emulsifying bacteria after screeningHydrocarbon degradation to produce surface active bacteria, fermenting to obtain bacteria with concentration of 10 ⁷ -10 ⁸ The cfu/mL fresh fermentation broth is added for 5mL, centrifugation is carried out for 5min under 8000r/min, the supernatant is discarded, the thallus is added into 5mL of sterilized normal saline for eluting for 3 times, then 100mL of solution of the weak base ternary oil displacement system is added, the mixture is put into a constant temperature oscillator for second oscillation, the surface tension is detected according to the second determination time, the control group is only added with the same amount of weak base ternary oil displacement system, and the result is shown in Table 9 after bad strains are removed.

TABLE 9

As shown in Table 9, the fermentation liquid of hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surfactant-producing bacteria in the microbial system can strengthen the surface activity of the weak base ternary oil displacement system, so that the surface tension of the weak base ternary oil displacement system is lower and more stable.

3. Overall experimental procedure:

the first measurement and the second measurement can obtain a stable weak base ternary oil displacement system which can better stabilize hydrocarbon degradation emulsifying bacteria H65-4 and hydrocarbon degradation surface active bacteria H65-6 and can reproduce by itself,

preparing a nutrition activating agent: after fermentation treatment of 0.4% corn steep liquor, 0.2% sodium nitrate, 0.2% dipotassium hydrogen phosphate and 0.05% yeast powder, and then 0.4% corn steep liquor, 0.2% sodium nitrate, 0.2% dipotassium hydrogen phosphate or 0.05% yeast powder are independently subjected to hydrocarbon degradation emulsifying bacteria H65-4 and hydrocarbon degradation active bacteria H65-6, each fermentation broth is independently added with 100mL of solution of weak base ternary oil displacement system, stirred and dissolved, detection is carried out at the first measuring moment under the condition of first oscillation, and the control group is only added with the same amount of weak base ternary oil displacement system, so that table 10 is obtained.

Table 10

As can be seen from Table 10, the oil displacement system consisting of the microbial oil displacement system and the weak base ternary oil displacement system can be stably stored for 30 days, so that the microbial oil displacement system can be used for stabilizing the weak base ternary oil displacement system.

Example 2

Comparing example 2 with example 1, example 2 differs from example 1 in that:

the microbial oil displacement system comprises the following components in percentage by mass: hydrocarbon degrading emulsifying bacteria: 0.4% of hydrocarbon degradation to produce surface active bacteria: 0.4%, nutritional activator: 10%, the balance being water;

The weak base ternary oil displacement system comprises the following components in percentage by mass: anionic surfactant: 0.2%, polymer: 0.1%, sodium carbonate: 0.1% and the balance of water.

The nutritional activator comprises, in mass fraction: microbial activator: 0.1%, nitrogen source: 0.1%, yeast powder: 0.03%, the balance being water.

The microbial activator is molasses and liquid paraffin with the mass ratio of 1:1, and the nitrogen source is ammonium chloride and urea with the mass ratio of 1:1.

The mass concentration of hydrocarbon degradation emulsifying bacteria is 4700mg/L, the mass concentration of hydrocarbon degradation surface active bacteria is 4700mg/L, the mass concentration of anionic surfactant is 700mg/L, the mass concentration of polymer is 1200mg/L, and the mass concentration of sodium carbonate is 1000mg/L.

The temperature of the first oscillation is 55 ℃, and the rotating speed of the first oscillation is 160r/mnn.

The temperature of the second oscillation is 65 ℃, and the rotating speed of the second oscillation is 160r/min.

The weak base ternary oil displacement system comprises: petroleum sulfonate type surfactant: 0.2%, partially hydrolyzed polyacrylamide: 0.1%, sodium carbonate: 0.1% and the balance of water.

Example 3

Comparing example 3 with example 1, example 3 differs from example 1 in that:

the microbial oil displacement system comprises the following components in percentage by mass: hydrocarbon degrading emulsifying bacteria: 1, hydrocarbon degradation to produce surface active bacteria: 1%, nutritional activator: 10%, the balance being water;

The weak base ternary oil displacement system comprises the following components in percentage by mass: anionic surfactant: 0.6%, polymer: 0.3% sodium carbonate: 0.3% and the balance of water.

The nutritional activator comprises, in mass fraction: microbial activator: 0.4%, nitrogen source: 0.3%, yeast powder: 0.1% and the balance of water.

The microbial activator is soybean oil and the nitrogen source is urea.

The mass concentration of hydrocarbon degradation emulsifying bacteria is 5000mg/L, the mass concentration of hydrocarbon degradation surfactant is 5000mg/L, the mass concentration of anionic surfactant is 2500mg/L, the mass concentration of polymer is 1500mg/L, and the mass concentration of sodium carbonate is 3000mg/L.

The temperature of the first oscillation is 65 ℃, and the rotating speed of the first oscillation is 200r/min.

The temperature of the second oscillation is 75 ℃, and the rotating speed of the second oscillation is 200r/min.

The weak base ternary oil displacement system comprises: petroleum sulfonate type surfactant: 0.6%, partially hydrolyzed polyacrylamide: 0.3% sodium carbonate: 0.3% and the balance of water.

Example 4

Comparing example 4 with example 1, example 4 differs from example 1 in that:

The temperature of the first oscillation is 55 ℃, and the rotating speed of the first oscillation is 160r/min.

Example 5

Comparing example 5 with example 1, example 5 differs from example 1 in that:

Comparative example 1

Comparative example 1 and example 1 are compared, and the difference between comparative example 1 and example 1 is that:

only a weak base ternary oil displacement system is adopted as an oil displacement system.

Comparative example 2

only a microbial oil displacement system is adopted as an oil displacement system.

Related experiments:

the flooding systems obtained in examples 1-5 and comparative examples 1-2 were subjected to performance tests, and the recovery enhancement rates thereof in the high-pour-point oil recovery stage were respectively tested, and the results are shown in Table 11.

Test method of related experiment:

harvesting improvement rate: testing is carried out according to QSY17004-2017 'surfactant technical Specification for weak base ternary complex flooding' and QSY1583-2013 'method for measuring oil displacement efficiency in surfactant technical Specification for binary complex flooding'

TABLE 11

Specific analysis of table 11:

the recovery improvement rate (%) refers to the improvement degree of the recovery ratio of the high-freezing oil before and after the oil displacement system is added, and when the recovery improvement rate (%) indicates that the oil displacement system has more obvious effect of improving the recovery of the high-freezing oil.

From the data of examples 1-5, it can be seen that:

the oil displacement system can effectively improve the recovery ratio of the high-freezing oil, and meanwhile, the addition of each raw material in the microbial oil displacement system and the weak base ternary oil displacement system in the oil displacement system can be controlled according to the actual cost requirement.

According to the method, the weak base ternary oil displacement system and the microbial oil displacement system are screened, so that the recovery ratio can reach more than 33%.

From the data of comparative examples 1-2, it can be seen that:

if the oil displacement system provided by the application is not adopted, only a weak base ternary oil displacement system or a microbial oil displacement system is used, the recovery improvement rate is only about 32%, and the oil exploitation efficiency cannot be effectively improved.

One or more technical solutions in the embodiments of the present application at least further have the following technical effects or advantages:

(1) According to the oil displacement system provided by the embodiment of the application, the hydrocarbon degradation emulsifying bacteria and the hydrocarbon degradation surface active bacteria which are cultured and screened by the weak base ternary oil displacement system are adopted in the microbial oil displacement system, so that the stability of the microbial oil displacement system in the weak base ternary oil displacement system can be effectively ensured, and the recovery rate of high-freezing oil can be improved.

(2) The oil displacement system provided by the embodiment of the application can improve the recovery ratio of the high-freezing oil by 35.19 percent, and is improved by 7.27 percent compared with a pure weak base ternary oil displacement system.

(3) The method provided by the embodiment of the application can screen out strains suitable for the high-pour-point oil environment and the oil displacement system environment, and the obtained oil displacement system can stably act on the high-pour-point oil.

It should be noted that in this document, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.

The foregoing is only a specific embodiment of the invention to enable those skilled in the art to understand or practice the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An oil displacement system for a high pour point oil reservoir, the oil displacement system comprising: a microbial oil displacement system and a weak base ternary oil displacement system;

2. The flooding system of claim 1, wherein the nutritional activator comprises, in mass percent: microbial activator: 0.1% -0.4%, nitrogen source: 0.1 to 0.3 percent of yeast powder: 0.03 to 0.1 percent and the balance of water.

3. The flooding system of claim 2, wherein said microbial activator comprises at least one of molasses, corn steep liquor dry powder, liquid paraffin and soybean oil, and said nitrogen source comprises at least one of sodium nitrate, ammonium chloride, urea and diammonium phosphate.

4. The flooding system according to claim 1, wherein the hydrocarbon degrading emulsifying bacteria have a mass concentration of 4700mg/L to 5000mg/L, the hydrocarbon degrading surfactant has a mass concentration of 4700mg/L to 5000mg/L, the anionic surfactant has a mass concentration of 700mg/L to 2500mg/L, the polymer has a mass concentration of 1200mg/L to 1500mg/L, and the sodium carbonate has a mass concentration of 1000mg/L to 3000mg/L.

5. The flooding system of claim 1, wherein said anionic surfactant is a petroleum sulfonate surfactant and said polymer is a partially hydrolyzed polyacrylamide.

6. A method of preparing the flooding system of any one of claims 1-5, comprising:

7. The method of claim 6, wherein the adding the hydrocarbon degrading emulsifying bacteria of different strains and the hydrocarbon degrading surface active bacteria of different strains into the weak base ternary complex system for culture and first single factor experiment to obtain an optimal weak base ternary displacement system comprises the following steps:

Obtaining a standard weak base ternary oil displacement system;

obtaining a standard nutrition activator;

8. The method of claim 7, wherein the obtaining the optimal weak base ternary displacement system according to the first cell quantity change rate, the second cell quantity change rate, and the third cell quantity change rate specifically comprises:

9. The method of claim 6, wherein the adding the microbial flooding system to the optimal weak base ternary flooding system for cultivation and a second single factor experiment results in an optimal microbial flooding system, specifically comprising:

10. The method of claim 9, wherein the first determination is performed on a first day of the first oscillation, a fourth day of the first oscillation, a tenth day of the first oscillation, a fifteenth day of the first oscillation, and a thirty th day of the first oscillation in that order.

11. The method according to claim 9 or 10, wherein the temperature of the first oscillation is 55 ℃ to 65 ℃ and the rotational speed of the first oscillation is 160r/min to 200r/min.

12. The method of claim 9, wherein the second determination is performed on a first day of the second oscillation, a fourth day of the second oscillation, a tenth day of the second oscillation, a fifteenth day of the second oscillation, and a thirty th day of the second oscillation in that order.

13. The method according to claim 9 or 12, wherein the temperature of the second oscillation is 65-75 ℃, and the rotational speed of the second oscillation is 160-200 r/min.

14. The method according to claim 6, wherein the hydrocarbon degrading emulsifying bacteria and hydrocarbon degrading surface active bacteria respectively obtained from different strains specifically comprise:

obtaining microorganisms of the oil well produced liquid;

15. Use of the flooding system for a high pour point reservoir, characterized in that the flooding system according to any one of claims 1-5 is used for flooding recovery of high pour point.