Disclosure of Invention
In order to overcome the defects of the conventional fracturing fluid, the invention aims to provide an intelligent oil displacement system capable of identifying crude oil and water in a reservoir.
The oil displacing system is weak gel formed by the synergistic effect of small molecular surfactant and other compounds after being dissolved in water, so that the oil displacing system has the characteristics of surfactant oil displacing agent and the properties of polymer oil displacing agent. More importantly, the system can break gel when meeting oil and water, namely the viscosity is greatly reduced until the viscosity is the same as that of water. The system can break gel when meeting 5-10 times of water, but 5-10% of crude oil can break gel, namely the system has obvious difference on the induction of oil and water, and the sensitivity degree is different by about 100 times. The invention utilizes the characteristic to research and develop the oil displacement agent, so that the viscosity of the oil displacement agent is not obviously changed when the oil displacement agent enters a reservoir migration process, the viscosity is easily and rapidly reduced to form a surfactant solution when the oil displacement agent meets crude oil, and the oil-water identification effect can be generated through viscosity response. Thus, the oil displacement agent system with high viscosity has poor fluidity in a high water-containing area, and forms a certain profile control effect; and the high-viscosity colloid in a high-oil-content area is converted into a low-viscosity oil displacement agent system, so that the fluidity is good, and a guiding effect is generated. Active components capable of reducing interfacial tension and having a good emulsification effect are introduced into the intelligent oil displacement agent in source design, so that a broken surfactant solution becomes a surfactant oil displacement agent, crude oil is easily carried out of a reservoir, the influence on original water in the reservoir is small, and intelligent oil displacement is finally realized.
In order to achieve the purpose, the invention adopts the technical scheme that:
an intelligent oil displacement agent and a using process thereof comprise the following steps:
firstly, mixing and stirring a cationic surfactant and a sulfobetaine surfactant uniformly according to a ratio of 10:1-2 in a reaction kettle, wherein the cationic surfactant is dodecyl trimethyl ammonium chloride, tetradecyl trimethyl ammonium chloride, hexadecyl trimethyl ammonium chloride, octadecyl trimethyl ammonium chloride, eicosyl trimethyl ammonium chloride, docosyl trimethyl ammonium chloride, dodecyl trimethyl ammonium bromide, tetradecyl trimethyl ammonium bromide, hexadecyl trimethyl ammonium bromide, octadecyl trimethyl ammonium bromide, eicosyl trimethyl ammonium bromide, docosyl trimethyl ammonium bromide, cocoyl propyl trimethyl ammonium chloride, palm oil acyl propyl trimethyl ammonium chloride, oleoyl propyl trimethyl ammonium chloride and a composition thereof, and the sulfobetaine surfactant is dodecyl dimethyl sulfobetaine, dodecyl trimethyl ammonium chloride, cocoyl propyl trimethyl ammonium chloride, palmitoyl propyl trimethyl ammonium chloride and a composition thereof with industrial grade and above purity, Tetradecyldimethyl sulfobetaine, hexadecyldimethylsulfobetaine, octadecyldimethyl sulfobetaine, eicosyldimethyl sulfobetaine, docosyldimethyl sulfobetaine, lauramidopropyl sulfobetaine, oleaamidopropyl sulfobetaine, erucamidopropyl sulfobetaine, cocamidopropyl sulfobetaine, and combinations thereof;
secondly, adding salicylic acid or salt thereof with the total mass of 40-60% into the mixture, and uniformly stirring, wherein the salicylic acid or salt thereof is salicylic acid, sodium salicylate, ammonium salicylate, potassium salicylate with the purity of industrial grade or above and a composition thereof;
thirdly, adding thiosulfate with the total mass of 2-5% into the system, and uniformly stirring, wherein the thiosulfate is sodium thiosulfate, potassium thiosulfate, ammonium thiosulfate and a composition thereof with the purity of industrial grade or above;
and fourthly, adding an oil-water recognition enhancer with the total mass of 1-3% into the system, and uniformly stirring to obtain the intelligent oil-displacing agent, wherein the oil-water recognition enhancer is sodium iodide, potassium iodide and a composition thereof with the purity of industrial grade or above.
When in application, the oil displacement agent is dissolved in water and uniformly stirred to prepare 0.3-1% of glue solution, so that the glue solution with the viscosity of 3-10mPa & s is formed and is injected into a reservoir along with an oil field water injection well. The SY/T6424-2014 composite oil displacement system performance test method is adopted to carry out oil displacement experiments, and the experimental result shows that the recovery ratio can be improved by more than 16%. The identification capacity of the oil displacement agent to water and oil is measured by a dilution method, namely the volume ratio of water to oil consumed by adding water or oil into the oil displacement agent to reduce the viscosity of the water to be more than 80 times that of the oil displacement agent.
Examples
The invention is further illustrated by the following examples. It should be understood that the method described in the examples is only for illustrating the present invention and not for limiting the present invention, and that simple modifications of the preparation method of the present invention based on the concept of the present invention are within the scope of the claimed invention. All the starting materials and solvents used in the examples are commercially available products.
Example 1:
firstly, mixing and stirring a cationic surfactant and a sulfobetaine surfactant uniformly in a reaction kettle according to a ratio of 10:1, wherein the cationic surfactant is industrial-grade hexadecyl trimethyl ammonium chloride, and the sulfobetaine surfactant is industrial-grade cocoamido propyl sulfobetaine;
secondly, adding salicylic acid or salt thereof which accounts for 50 percent of the total mass into the mixture, and uniformly stirring, wherein the salicylic acid or salt thereof is industrial grade ammonium salicylate and potassium salicylate with the mass ratio of 1: 1;
thirdly, adding thiosulfate accounting for 2 percent of the total mass into the system, and uniformly stirring, wherein the thiosulfate is industrial-grade sodium thiosulfate;
and fourthly, adding an iodide oil-water resistant recognition enhancer with the total mass of 3% into the system, and uniformly stirring to obtain the intelligent oil-displacing agent, wherein the oil-water recognition enhancer is industrial-grade potassium iodide.
When in application, the oil displacement agent is dissolved in water and uniformly stirred to prepare 0.4% glue solution, so that the glue solution with the viscosity of 5mPa & s is formed and is injected into a reservoir along with an oil field water injection well. The performance test method of the SY/T6424-2014 composite oil displacement system is adopted to carry out the oil displacement experiment, and the experiment result shows that the recovery ratio can be improved by 23 percent. The identification capacity of the oil displacement agent to water and oil is measured by a dilution method, namely the volume ratio of water to oil consumed by adding water or oil into the oil displacement agent to reduce the viscosity of the water to 120 times that of the oil displacement agent.
Example 2:
firstly, mixing and stirring a cationic surfactant and a sulfobetaine surfactant uniformly in a reaction kettle according to a ratio of 10:1.1, wherein the cationic surfactant is chemically pure octadecyl trimethyl ammonium bromide, and the sulfobetaine surfactant is chemically pure oleic acid amide propyl sulfobetaine;
secondly, adding salicylic acid or salt thereof which accounts for 45 percent of the total mass into the mixture, and uniformly stirring, wherein the salicylic acid or salt thereof is chemical pure sodium salicylate;
thirdly, adding thiosulfate accounting for 5 percent of the total mass into the system, and uniformly stirring, wherein the thiosulfate is analytically pure ammonium thiosulfate;
fourthly, adding an iodide oil-water recognition enhancer with the total mass of 2.5 percent into the system, and uniformly stirring to obtain the intelligent oil-displacing agent, wherein the oil-water recognition enhancer is chemically pure potassium iodide.
When in application, the oil displacement agent is dissolved in water and uniformly stirred to prepare 0.25% glue solution, so that the glue solution with the viscosity of 3mPa & s is formed and is injected into a reservoir along with an oil field water injection well. The performance test method of the SY/T6424-2014 composite oil displacement system is adopted to carry out an oil displacement experiment, and the experiment result shows that the recovery ratio can be improved by 18 percent. The identification capacity of the oil displacement agent to water and oil is measured by a dilution method, namely the volume ratio of water to oil consumed by adding water or oil into the oil displacement agent to reduce the viscosity of the water to 110 times that of the oil displacement agent.
Example 3:
firstly, mixing and stirring a cationic surfactant and a sulfobetaine surfactant uniformly in a reaction kettle according to a mass ratio of 10:1.2, wherein the cationic surfactant is analytically pure octadecyl trimethyl ammonium chloride and docosyl trimethyl ammonium bromide with a mass ratio of 9:1, and the sulfobetaine surfactant is analytically pure docosyl dimethyl sulfobetaine;
secondly, adding salicylic acid or salt thereof accounting for 42% of the total mass of the mixture, and uniformly stirring, wherein the salicylic acid or salt thereof is analytically pure salicylic acid;
thirdly, adding thiosulfate accounting for 3 percent of the total mass into the system, and uniformly stirring, wherein the thiosulfate is analytically pure potassium thiosulfate;
and fourthly, adding an iodide oil-water recognition enhancer with the total mass of 2% into the system, and uniformly stirring to obtain the intelligent oil-displacing agent, wherein the oil-water recognition enhancer is analytically pure sodium iodide.
When in application, the oil displacement agent is dissolved in water and uniformly stirred to prepare 0.15% glue solution, so that the glue solution with the viscosity of 3mPa & s is formed and is injected into a reservoir along with an oil field water injection well. The performance test method of the SY/T6424-2014 composite oil displacement system is adopted to carry out the oil displacement experiment, and the experiment result shows that the recovery ratio can be improved by 19 percent. The identification capacity of the oil displacement agent to water and oil is measured by a dilution method, namely the volume ratio of water to oil consumed by adding water or oil into the oil displacement agent to reduce the viscosity of the water to be 85 times that of the oil displacement agent.
Example 4:
firstly, mixing and stirring a cationic surfactant and a sulfobetaine surfactant uniformly in a reaction kettle according to a mass ratio of 10:1.5, wherein the cationic surfactant is industrial-grade octadecyl trimethyl ammonium chloride and palm oil acyl propyl trimethyl ammonium chloride in a mass ratio of 5:1, and the sulfobetaine surfactant is industrial-grade hexadecyl dimethyl sulfobetaine and eicosyl dimethyl sulfobetaine in a mass ratio of 2: 1;
secondly, adding salicylic acid or salt thereof accounting for 55% of the total mass into the mixture, and uniformly stirring, wherein the salicylic acid or salt thereof is industrial-grade sodium salicylate;
thirdly, adding thiosulfate with the total mass of 2.5 percent into the system, and uniformly stirring, wherein the thiosulfate is industrial-grade ammonium thiosulfate;
and fourthly, adding an iodide oil-water recognition enhancer with the total mass of 1% into the system, and uniformly stirring to obtain the intelligent oil-displacing agent, wherein the oil-water recognition enhancer is industrial-grade sodium iodide.
When in application, the oil displacement agent is dissolved in water and uniformly stirred to prepare 0.3% glue solution, so that the glue solution with the viscosity of 6mPa & s is formed and is injected into a reservoir along with an oil field water injection well. The performance test method of the SY/T6424-2014 composite oil displacement system is adopted to carry out the oil displacement experiment, and the experiment result shows that the recovery ratio can be improved by 19 percent. The identification capacity of the oil displacement agent to water and oil is measured by a dilution method, namely the volume ratio of water to oil consumed by adding water or oil into the oil displacement agent to reduce the viscosity of the water to 140 times that of the oil displacement agent.
Example 5:
firstly, mixing and stirring a cationic surfactant and a sulfobetaine surfactant uniformly in a reaction kettle according to a mass ratio of 10:1.8, wherein the cationic surfactant is chemically pure cetyl trimethyl ammonium bromide and cocoyl propyl trimethyl ammonium chloride in a mass ratio of 8:1, and the sulfobetaine surfactant is chemically pure erucamide propyl sulfobetaine;
secondly, adding salicylic acid or salt thereof accounting for 60% of the total mass into the mixture, and uniformly stirring, wherein the salicylic acid or salt thereof is chemical pure ammonium salicylate;
and thirdly, adding thiosulfate accounting for 4 percent of the total mass into the system, and uniformly stirring, wherein the thiosulfate is industrial-grade sodium thiosulfate and ammonium thiosulfate with the mass ratio of 1: 2.
And fourthly, adding an iodide oil-water recognition enhancer with the total mass of 2% into the system, and uniformly stirring to obtain the intelligent oil-displacing agent, wherein the oil-water recognition enhancer is industrial sodium iodide and potassium iodide with the mass ratio of 1: 2.
When in application, the oil displacement agent is dissolved in water and uniformly stirred to prepare 0.5% glue solution, so that the glue solution with the viscosity of 9mPa & s is formed and is injected into a reservoir along with an oil field water injection well. The performance test method of the SY/T6424-2014 composite oil displacement system is adopted to carry out the oil displacement experiment, and the experiment result shows that the recovery ratio can be improved by 24 percent. The identification capacity of the oil displacement agent to water and oil is measured by a dilution method, namely the volume ratio of water to oil consumed by adding water or oil into the oil displacement agent to reduce the viscosity of the water to be 150 times that of the oil displacement agent.
Example 6:
step one, mixing and stirring a cationic surfactant and a sulfobetaine surfactant uniformly in a reaction kettle according to a mass ratio of 10:2, wherein the cationic surfactant is prepared from the following components in parts by mass of 1: 8:1, the sulfobetaine surfactant is prepared from the following components in a mass ratio of 2: 5: 3 technical grade dodecyl dimethyl sulfobetaine, docosyl dimethyl sulfobetaine, and lauramidopropyl sulfobetaine;
secondly, adding salicylic acid or salt thereof accounting for 60% of the total mass into the mixture, and uniformly stirring, wherein the salicylic acid or salt thereof is industrial-grade potassium salicylate;
and thirdly, adding thiosulfate accounting for 5 percent of the total mass into the system, and uniformly stirring, wherein the thiosulfate is industrial-grade sodium thiosulfate.
Fourthly, adding an iodide oil-water recognition enhancer with the total mass of 2.5 percent into the system, and uniformly stirring to obtain the intelligent oil-displacing agent, wherein the oil-water recognition enhancer is industrial-grade sodium iodide;
when in application, the oil displacement agent is dissolved in water and uniformly stirred to prepare 0.2% glue solution, so that the glue solution with the viscosity of 5mPa & s is formed and is injected into a reservoir along with an oil field water injection well. The performance test method of the SY/T6424-2014 composite oil displacement system is adopted to carry out an oil displacement experiment, and the experiment result shows that the recovery ratio can be improved by 18 percent. The identification capacity of the oil displacement agent to water and oil is measured by a dilution method, namely the volume ratio of water to oil consumed by adding water or oil into the oil displacement agent to reduce the viscosity of the water to be 100 times that of the oil displacement agent.