CN110819332A - Intelligent oil displacement agent for oil-water recognition based on small molecular gel and preparation method thereof - Google Patents

Abstract

The invention relates to an intelligent oil-displacing agent based on the identification of oil and water by small molecular gel and a preparation method thereof. The method includes mixing a cationic surfactant and a sulfobetaine surfactant; adding salicylic acid or a salt thereof to the mixture; adding a thiosulfate to the above system; adding an oil-water identification enhancer to the above system , and stir evenly to obtain an intelligent oil-displacing agent. The oil-displacing agent glue can improve the recovery rate by more than 16%, and the identification of oil and water is more than 80 times.

Description

An intelligent oil-displacing agent based on the recognition of oil and water by small molecular gel and its preparation method

technical field

The invention relates to the technical field of enhanced oil recovery, in particular to an intelligent oil-displacing agent and a process for using the same.

Background technique

Chemical flooding is a common method of tertiary oil recovery in oilfields. Chemical agents are added to injected water to change the physical and chemical properties of the displacing fluid and the interface properties between the displacing fluid and crude oil and rock minerals, which is beneficial to crude oil production. Oil extraction method. Chemical flooding mainly includes polymer flooding, polymer/surfactant binary composite flooding, surfactant/polymer/alkali ternary composite flooding, etc. The agents used are polymers, surfactants, alkalis and other auxiliary chemicals agent. All of these methods have certain applications, but all of them cannot identify oil and water, and a large amount of water is also produced during oil displacement, resulting in a continuous increase in the water content of the produced fluid and limited recovery.

Regarding the oil displacement agent, the small molecule surfactant gel is based on the surfactant solution by adding other components, including salts, alcohols, amines or other surface activities, to stimulate the solution or spherical micelles, so that the It forms linear or worm-like micelles, and the entanglement between the micelles forms viscosity. Different surfactants have different responses to stimuli, almost one-to-one. The cationic ones can be stimulated by salicylic acid or potassium chloride to form gels, while the anionic or zwitterionic ones have no corresponding response. It can form a gel when compounded with higher alcohols, but cationic and zwitterionic cannot. The addition of higher alcohols to the cationic surfactant gel will break the gel. Therefore, each gel system is different, and there may be similarities in the change of carbon chain or, otherwise, even if it is the same surfactant, the addition of different external stimulants will result in different gels, such as cetyl trimethyl. The gel can be formed by adding salicylic acid to ammonium chloride, and it can also be formed by adding a chlorinating agent. There is no similarity between the two, but cetyltrimethylammonium chloride is used.

SUMMARY OF THE INVENTION

In order to overcome the shortcomings of the existing fracturing fluids, the purpose of the present invention is to provide an intelligent oil displacement system that can identify crude oil and water in the reservoir.

The oil displacement system is a weak gel formed by the synergistic action of other compounds after dissolving small molecular surface active compounds in water, so it has the characteristics of a surfactant oil displacement agent and the properties of a polymer oil displacement agent. More importantly, the system can break the gel when it encounters both oil and water, that is, the viscosity drops greatly until the viscosity is the same as that of water. The system can break the gel when it encounters 5-10 times of water, but 5-10% crude oil can break the gel, that is, the system has a significant difference in the induction of oil and water, and the difference in sensitivity is about 100 times. The present invention utilizes this feature to develop the oil displacement agent, so that the viscosity of water does not change significantly when it enters the reservoir and migrates, but when it encounters crude oil, the viscosity is easily reduced sharply to form a surfactant solution, which can be generated by the viscosity response. Identification of oil and water. Such a high-viscosity oil-displacing agent system has poor fluidity in the high-water-cut area, forming a certain profile control effect; while in the high-oil-content area, the high-viscosity colloid transforms into a low-viscosity oil-displacing agent system, with good fluidity and a guiding effect. In the source design, active components that can reduce interfacial tension and have better emulsification are introduced into the intelligent oil displacement agent, so that the surfactant solution after gel breaking becomes a surfactant oil displacement agent, which is easy to carry crude oil out of storage. It has less impact on the original water in the reservoir, and finally realizes intelligent oil flooding.

In order to achieve the above object, the technical scheme adopted in the present invention is:

An intelligent oil displacing agent and a using process thereof, comprising the following steps:

The first step, in the reactor, the cationic surfactant and the sulfobetaine surfactant are mixed and stirred uniformly according to 10:1-2, and the cationic surfactant is the dodecyl triglyceride of technical grade and its above purity. Methyl ammonium chloride, tetradecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, eicosyl trimethyl ammonium chloride, Behenyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, octadecyltrimethylammonium bromide Methyl Ammonium Bromide, Eicosyl Trimethyl Ammonium Bromide, Behenyl Trimethyl Ammonium Bromide, Cocoylpropyl Trimethyl Ammonium Chloride, Palmoleoylpropyl Trimethyl Ammonium Chloride Ammonium chloride, oleoyl propyl trimethyl ammonium chloride and composition thereof, the sulfobetaine surfactant is industrial grade and above purity dodecyl dimethyl sulfobetaine, tetradecane Dimethyl sulfobetaine, cetyl dimethyl sulfobetaine, octadecyl dimethyl sulfobetaine, eicosyl dimethyl sulfobetaine, behenyl Dimethyl sulfobetaine, lauramidopropyl sulfobetaine, oleamidopropyl sulfobetaine, erucamidopropyl sulfobetaine, cocamidopropyl sulfobetaine, and combinations thereof thing;

In the second step, add 40-60% salicylic acid or its salt of the total mass to the mixture, stir evenly, and the salicylic acid or its salt are salicylic acid and sodium salicylic acid of technical grade and above purity , ammonium salicylate, potassium salicylate and compositions thereof;

The 3rd step, add the thiosulfate of total mass 2-5% in the above-mentioned system, stir, described thiosulfate is the sodium thiosulfate, potassium thiosulfate, thiosulfate of technical grade and its purity above Ammonium sulfate and its composition;

The fourth step is to add 1-3% oil-water identification enhancer of the total mass to the above-mentioned system, and stir evenly to obtain an intelligent oil-displacing agent. The oil-water identification enhancer is sodium iodide, potassium iodide and its composition.

In application, the oil displacement agent is dissolved in water, stirred evenly, and prepared into a glue solution of 0.3-1% to form a glue solution with a viscosity of 3-10 mPa·s, which can be injected into the reservoir along with the oilfield water injection well. The "SY/T 6424-2014 composite flooding system performance test method" was used to conduct oil displacement experiments, and the experimental results showed that the oil recovery could be increased by more than 16%. The ability of the glue to identify water and oil was determined by the dilution method, that is, the ratio of the volume of water and oil consumed by adding water or oil to the glue to reduce the viscosity of water to the viscosity of the water. The recognition is more than 80 times.

Description of drawings

Figure 1. Small molecule surface active compounds form gels;

Fig. 2 Identification of oil and water in reservoirs by intelligent oil displacement agents.

Example

The present invention will be further described below through examples. It should be understood that the methods described in the embodiments of the present invention are only used to illustrate the present invention, rather than to limit the present invention, and simple improvements to the preparation method of the present invention under the concept of the present invention all belong to the scope of protection of the present invention. All raw materials and solvents used in the examples are commercially available products.

Example 1:

The first step, in the reactor, the cationic surfactant and the sulfobetaine surfactant are mixed and stirred at a ratio of 10:1, and the cationic surfactant is technical grade cetyltrimethyl ammonium chloride, so Described sulfobetaine surfactant is technical grade cocamidopropyl sulfobetaine;

In the second step, add 50% salicylic acid or its salt of total mass to the mixture, stir evenly, and the salicylic acid or its salt are technical grade ammonium salicylate and salicylic acid whose mass ratio is 1:1 potassium;

The 3rd step, add the thiosulfate of total mass 2% in above-mentioned system, stir, and described thiosulfate is technical grade sodium thiosulfate;

In the fourth step, 3% of the total mass of iodide anti-oil and water identification enhancer is added to the above system, and the intelligent oil-displacing agent is obtained by stirring evenly. The oil and water identification enhancer is industrial grade potassium iodide.

In application, the oil displacement agent is dissolved in water, stirred evenly, and prepared into a glue solution of 0.4% to form a glue solution with a viscosity of 5mPa·s, which can be injected into the reservoir with the water injection well in the oil field. Using the "SY/T 6424-2014 composite flooding system performance test method" to conduct oil displacement experiments, the experimental results show that the oil recovery can be increased by 23%. The ability of the glue to identify water and oil was determined by the dilution method, that is, the ratio of the volume of water and oil consumed by adding water or oil to the glue to reduce the viscosity of water to the viscosity of the water. Recognition is 120 times.

Example 2:

The first step, in the reactor, the cationic surfactant and the sulfobetaine surfactant are mixed and stirred uniformly according to 10:1.1, and the cationic surfactant is chemically pure octadecyltrimethylammonium bromide, The sulfobetaine surfactant is chemically pure oleic acid amidopropyl sulfobetaine;

In the second step, add 45% of total mass salicylic acid or its salt to the mixture, stir evenly, and the salicylic acid or its salt is chemically pure sodium salicylate;

The 3rd step, add the thiosulfate of total mass 5% in the above-mentioned system, stir, and described thiosulfate is analytical pure ammonium thiosulfate;

In the fourth step, 2.5% of the total mass of iodide oil-water identification enhancer is added to the above system, and the intelligent oil-displacing agent is obtained by stirring evenly. The oil-water identification enhancer is chemically pure potassium iodide.

In application, the oil displacement agent is dissolved in water, stirred evenly, and prepared into a glue solution of 0.25% to form a glue solution with a viscosity of 3 mPa·s, which can be injected into the reservoir with the water injection well in the oil field. The "SY/T 6424-2014 composite flooding system performance test method" was used to conduct oil displacement experiments, and the experimental results showed that the oil recovery could be increased by 18%. The ability of the glue to identify water and oil was determined by the dilution method, that is, the ratio of the volume of water and oil consumed by adding water or oil to the glue to reduce the viscosity of water to the viscosity of the water. Recognition is 110 times.

Example 3:

The first step, in the reaction kettle, the cationic surfactant and the sulfobetaine surfactant are mixed and stirred uniformly according to 10:1.2, and the cationic surfactant is an analytically pure octadecyl triacetate with a mass ratio of 9:1. Methyl ammonium chloride and behenyl trimethyl ammonium bromide, the sulfobetaine surfactant is analytical pure behenyl dimethyl sulfobetaine;

In the second step, 42% of total mass salicylic acid or its salt is added to the mixture, and the mixture is uniformly stirred, and the salicylic acid or its salt is analytically pure salicylic acid;

The 3rd step, add the thiosulfate of total mass 3% in the above-mentioned system, stir, and described thiosulfate is analytically pure potassium thiosulfate;

In the fourth step, 2% of the total mass of iodide oil-water identification enhancer is added to the above system, and the intelligent oil-displacing agent is obtained by stirring evenly. The oil-water identification enhancer is analytically pure sodium iodide.

In application, the oil displacement agent is dissolved in water, stirred evenly, and prepared into a glue solution of 0.15% to form a glue solution with a viscosity of 3 mPa·s, which can be injected into the reservoir with the water injection well in the oil field. Using the "SY/T 6424-2014 composite flooding system performance test method" to carry out oil displacement experiments, the experimental results show that the oil recovery can be increased by 19%. The ability of the glue to identify water and oil was determined by the dilution method, that is, the ratio of the volume of water and oil consumed by adding water or oil to the glue to reduce the viscosity of water to the viscosity of the water. Recognition is 85 times.

Example 4:

The first step, in the reaction kettle, the cationic surfactant and the sulfobetaine surfactant are mixed and stirred uniformly according to 10:1.5, and the cationic surfactant is an industrial grade octadecyl triacetate with a mass ratio of 5:1. Methyl ammonium chloride and palm oil acyl propyl trimethyl ammonium chloride, the sulfobetaine surfactant is technical grade cetyl dimethyl sulfobetaine and dimethicone with a mass ratio of 2:1. dodecyl dimethyl sulfobetaine;

In the second step, add 55% of total mass salicylic acid or its salt to the mixture, stir evenly, and the salicylic acid or its salt is technical grade sodium salicylate;

The 3rd step, add the thiosulfate of total mass 2.5% in the above-mentioned system, stir, and described thiosulfate is technical grade ammonium thiosulfate;

In the fourth step, 1% of the total mass of iodide oil-water identification enhancer is added to the above system, and the intelligent oil-displacing agent is obtained by stirring evenly. The oil-water identification enhancer is industrial grade sodium iodide.

In application, the oil displacement agent is dissolved in water, stirred evenly, and prepared into a glue solution of 0.3% to form a glue solution with a viscosity of 6 mPa·s, which can be injected into the reservoir with the water injection well in the oil field. Using the "SY/T 6424-2014 composite flooding system performance test method" to carry out oil displacement experiments, the experimental results show that the oil recovery can be increased by 19%. The ability of the glue to identify water and oil was determined by the dilution method, that is, the ratio of the volume of water and oil consumed by adding water or oil to the glue to reduce the viscosity of water to the viscosity of the water. Recognition is 140 times.

Example 5:

The first step, in the reactor, the cationic surfactant and the sulfobetaine surfactant are mixed and stirred uniformly according to 10:1.8, and the cationic surfactant is a chemically pure hexadecyl triacetate with a mass ratio of 8:1. Methyl ammonium bromide and cocoylpropyl trimethyl ammonium chloride, the sulfobetaine surfactant is chemically pure erucic acid amidopropyl sulfobetaine;

In the second step, add 60% of total mass salicylic acid or its salt to the mixture, stir evenly, and the salicylic acid or its salt is chemically pure ammonium salicylate;

In the third step, 4% of total mass thiosulfate is added to the above-mentioned system, and the mixture is stirred evenly. The thiosulfate is technical grade sodium thiosulfate and ammonium thiosulfate with a mass ratio of 1:2.

In the fourth step, add 2% iodide oil-water identification enhancer by total mass to the above system, and stir evenly to obtain an intelligent oil-displacing agent. The oil-water identification enhancer is industrial-grade sodium iodide and Potassium iodide.

In application, the oil displacement agent is dissolved in water, stirred evenly, and prepared into a glue solution of 0.5% to form a glue solution with a viscosity of 9 mPa·s, which can be injected into the reservoir with the water injection well in the oil field. The "SY/T 6424-2014 composite flooding system performance test method" was used to conduct oil displacement experiments, and the experimental results showed that the oil recovery could be increased by 24%. The ability of the glue to identify water and oil was determined by the dilution method, that is, the ratio of the volume of water and oil consumed by adding water or oil to the glue to reduce the viscosity of water to the viscosity of the water. Recognition is 150 times.

Example 6:

The first step, in the reactor, the cationic surfactant and the sulfobetaine surfactant are mixed and stirred uniformly according to 10:2, and the cationic surfactant is an industrial grade dodecane with a mass ratio of 1:8:1 trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride, the sulfobetaine surfactant is a mass ratio of 2:5:3 Industrial grade dodecyl dimethyl sulfobetaine, behenyl dimethyl sulfobetaine and lauramidopropyl sulfobetaine;

In the second step, add 60% of total mass salicylic acid or its salt to the mixture, stir evenly, and the salicylic acid or its salt is technical grade potassium salicylate;

In the third step, 5% of the total mass of thiosulfate is added to the above system, and the mixture is stirred evenly. The thiosulfate is technical grade sodium thiosulfate.

The fourth step, adding 2.5% of the total mass of iodide oil-water identification enhancer to the above system, and stirring evenly to obtain an intelligent oil-displacing agent, the oil-water identification enhancer is industrial-grade sodium iodide;

In application, the oil displacement agent is dissolved in water, stirred evenly, and prepared into a 0.2% glue solution to form a glue solution with a viscosity of 5 mPa·s, which can be injected into the reservoir along with the water injection well in the oil field. The "SY/T 6424-2014 composite flooding system performance test method" was used to conduct oil displacement experiments, and the experimental results showed that the oil recovery could be increased by 18%. Dilution method was used to determine the ability of glue to identify water and oil, that is, the ratio of the volume of water and oil consumed by adding water or oil to the glue to reduce it to the viscosity of water. Recognition is 100 times.

Claims (8)

1. a kind of preparation method of the intelligent oil-displacing agent based on small molecule gel to oil-water identification, is characterized in that comprising the following steps: 1), in the reactor, the cationic surfactant and the sulfobetaine surfactant are mixed and stirred according to 10:1-2; 2), add the salicylic acid or its salt of total mass 40-60% to this mixture, stir; 3), add the thiosulfate of total mass 2-5% in above-mentioned system, stir; 4), adding 1-3% of the total mass of the oil-water identification enhancer to the above system, and stirring evenly to obtain the intelligent oil-displacing agent. 2. preparation method according to claim 1 is characterized in that: in step 1) in, described cationic surfactant is selected from the lauryl trimethyl ammonium chloride of technical grade and its above purity, tetradecyl trimethyl ammonium chloride Alkyl trimethyl ammonium chloride, cetyl trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, eicosyl trimethyl ammonium chloride, behenyl trimethyl ammonium chloride Ammonium chloride, dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide, twenty Alkyl trimethyl ammonium bromide, behenyl trimethyl ammonium bromide, cocoyl propyl trimethyl ammonium chloride, palm oil acyl propyl trimethyl ammonium chloride, oleoyl propyl trimethyl ammonium chloride One or more in methyl ammonium chloride, and described sulfobetaine surfactant is selected from industrial grade and above purity dodecyl dimethyl sulfobetaine, tetradecyl dimethyl sulfobetaine sulfobetaine, cetyldimethyl sulfobetaine, octadecyl dimethyl sulfobetaine, eicosyl dimethyl sulfobetaine, behenyl dimethyl sulfobetaine One or more of betaine, lauramidopropyl sulfobetaine, oleic acid amidopropyl sulfobetaine, erucic acid amidopropyl sulfobetaine, and cocamidopropyl sulfobetaine . 3. preparation method according to claim 1, is characterized in that: in step 2) in, described salicylic acid or its salt are selected from technical grade and the above purity salicylic acid, sodium salicylate, salicylic acid One or more of ammonium acid and potassium salicylate. 4. preparation method according to claim 1 is characterized in that: in step 3) in, described thiosulfate is selected from technical grade and the above purity sodium thiosulfate, potassium thiosulfate, thiosulfuric acid One or more of ammonium. 5. preparation method according to claim 1, is characterized in that: in step 4), described oil-water identification enhancer is selected from one or more in sodium iodide and potassium iodide of industrial grade and its purity above. 6. An intelligent oil-displacing agent based on the recognition of oil and water by small molecular gel, characterized in that it is prepared by the method described in any one of claims 1-5. 7. The method for using the intelligent oil-displacing agent according to claim 6, characterized in that: the oil-displacing agent is dissolved in water, stirred evenly, and prepared into a glue solution of 0.3-1% to form a viscosity of 3-10 mPa·s The glue can be injected into the reservoir with the oilfield water injection well. 8. Use of the intelligent oil-displacing agent according to claim 6 in petrochemical industry.

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