CN111909678A

CN111909678A - Efficient nano oil displacement agent and preparation method thereof

Info

Publication number: CN111909678A
Application number: CN202010865018.3A
Authority: CN
Inventors: 姜涛
Original assignee: Daqing Zhonglian Xinshi Petroleum Technology Development Co ltd
Current assignee: Daqing Zhonglian Xinshi Petroleum Technology Development Co ltd
Priority date: 2020-08-25
Filing date: 2020-08-25
Publication date: 2020-11-10

Abstract

Discloses a high-efficiency nano oil-displacing agent, which comprises surface-modified hydrophilic nano silicon dioxide, sodium lauroyl glucoside hydroxypropyl sulfonate, sodium alpha-olefin sulfonate and water; in addition, a preparation method thereof is also disclosed. The nano oil displacement agent has better dispersibility and higher crude oil recovery ratio.

Description

Efficient nano oil displacement agent and preparation method thereof

Technical Field

The invention belongs to the technical field of drilling compositions, and particularly relates to an efficient nano oil displacement agent and a preparation method thereof.

Background

After many years of development, the oil field industry has classified oil recovery modes into primary oil recovery, secondary oil recovery and tertiary oil recovery according to the difference in energy dependence in oil field development.

After primary and secondary oil recovery, about two thirds of the crude oil is trapped by the reservoir under capillary action, dispersed in the discontinuous phase to form oil droplets, and left in the reservoir. At the moment, the stripping efficiency of the injected fluid to the crude oil can be improved and the displacement efficiency can be improved by using advanced process technologies such as physics, chemistry and the like based on the three-phase interface effect of the rock-crude oil and the injected fluid, and the residual oil is extracted to a certain extent, which is also called as the improvement of the crude oil recovery ratio.

As a technique for enhancing the recovery of crude oil, there are generally three types, thermal recovery, gas flooding and chemical flooding. Thermal recovery comprises technologies such as steam flooding, hot water flooding, in-situ oil burning, SADG and the like; the gas drive comprises the technologies of miscible-phase drive, unmiscible-phase drive and the like; the chemical flooding comprises polymer flooding, surfactant flooding, composite flooding, nano chemical flooding and other technologies.

In recent years, the most studied nanochemical drive is nano-SiO₂Granular, nano SiO₂The particles have hydrophilicity, and nanometer SiO is added into pure water solution₂After granulation, foam can be generated by simply shaking. And nano SiO₂The particles have large specific surface area and surface energy, the oil-water interfacial tension can be reduced, and after fluid enters pores of a reservoir, crude oil can be easily peeled off to form small oil drops which are displaced along with the oil displacement agent.

Chinese patent application CN104152132A discloses a modified nano-silica foam stabilizer and a preparation method thereof. The nano foam stabilizer is prepared by hydrophilic modification of nano silicon dioxide by maleic anhydride. The nano foam stabilizer is used for improving the foam stabilizing performance of a foam flooding system, has the characteristics of simple preparation process, excellent foaming performance and good foam stabilizing performance, and particularly has the characteristics of excellent foaming performance and excellent foam stabilizing performance when being compounded and applied with polyacrylamide serving as an organic polymer foam stabilizer.

Chinese patent application CN108410440A discloses a surface modified nano-silica nanofluid for improving recovery efficiency, which is obtained by dispersing acid anhydride modified surface modified nano-silica in water to obtain a dispersion liquid. The anhydride modified surface modified nano-silica can be self-dispersed in water without adding any dispersant, has good dispersibility and stability, low cost of raw materials, easy preparation on site and large-scale popularization, and can effectively improve the crude oil recovery ratio of low-permeability oil reservoirs.

However, the nano-silica is easy to form agglomeration spontaneously, so that the nano-effect of the nano-particles is limited, and the application effect of the nano-particles is reduced. Although the surface modification greatly improves the agglomeration phenomenon of the nanoparticles, the surface modification is a double-edged sword and still influences the dispersibility of the surface-modified nano material in water, so that the crude oil recovery rate of the nano oil displacement agent is still unsatisfactory.

Therefore, in order to overcome the defects in the prior art, an efficient nano oil displacement agent with better dispersibility and higher crude oil recovery rate and a preparation method thereof need to be found.

Disclosure of Invention

Aiming at the problems, the invention aims to provide an efficient nano oil displacement agent and a preparation method thereof. Compared with the prior art, the nano oil displacement agent has better dispersibility and higher crude oil recovery rate.

In order to achieve the purpose, on one hand, the invention adopts the following technical scheme: the nano oil displacement agent is characterized by comprising surface-modified hydrophilic nano silicon dioxide, sodium lauroyl glucoside hydroxypropyl sulfonate, sodium alpha-olefin sulfonate and water.

The nano oil-displacing agent is characterized in that the surface-modified hydrophilic nano silicon dioxide is selected from succinic anhydride or maleic anhydride modified hydrophilic nano silicon dioxide.

The nano oil displacement agent is characterized in that the hydrophilic nano silicon dioxide is selected from hydroxylated nano silicon dioxide.

The nano oil displacement agent is prepared from the following components in parts by weight: mixing 2-4 parts by volume of TEOS and 10 parts by volume of absolute ethyl alcohol uniformly, adding the mixture into a mixed solution formed by mixing 0.5-1.5 parts by volume of ammonia water, 0.5-1.5 parts by volume of distilled water and 10 parts by volume of absolute ethyl alcohol, and reacting for 4-8 hours under the condition of stirring to obtain the TEOS.

The nano oil displacement agent provided by the invention is characterized in that the average diameter of the hydroxylated nano silica is 10-40 nm.

The nano oil displacement agent comprises 0.01-0.8 wt% of surface-modified hydrophilic nano silicon dioxide; preferably 0.05 to 0.2 wt%.

The nano oil displacement agent comprises 0.05-0.60 wt% of sodium lauroyl glucoside hydroxypropyl sulfonate; preferably 0.08-0.25 wt%.

The nano oil-displacing agent provided by the invention is characterized in that the content of alpha-olefin sodium sulfonate is 0.01-0.40 wt%; preferably 0.03 to 0.09 wt%.

The nano oil displacement agent provided by the invention is characterized in that the balance is water, and the pH value of the nano oil displacement agent is 10-12.

On the other hand, the invention also provides a method for preparing the nano oil displacement agent, which comprises the following steps: according to the formula ratio, the components are uniformly mixed, and the pH value is adjusted to 10-12, so that the nano oil-displacing agent is obtained.

The invention has the beneficial effects that: compared with the prior art, the high-efficiency nano oil displacement agent has better dispersibility and higher crude oil recovery ratio.

Without wishing to be bound by any theory, the combination surfactant lauroyl glucoside sodium hydroxypropyl sulfonate and sodium alpha-olefm sulfonate of the present invention together enhance the above-described beneficial effects of the surface modified hydrophilic nanosilica.

Detailed Description

The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, articles, devices, and/or methods described and claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for.

Parts are parts by weight unless otherwise indicated. The weight parts of the components are calculated based on the total weight of the nano oil displacement agent. The temperatures are all expressed in degrees celsius or at ambient temperature and the pressure is at or near atmospheric pressure. There are many variations and combinations of reaction conditions (e.g., component concentrations, desired solvents, solvent mixtures, temperatures, pressures, and other reaction ranges) and conditions that can be used to optimize the purity and yield of the product obtained by the process. Only reasonable routine experimentation will be required to optimize such process conditions.

Example 1

Step 1: mixing 3 parts by volume of TEOS and 10 parts by volume of absolute ethyl alcohol uniformly, adding the mixture into a mixed solution formed by mixing 1 part by volume of ammonia water, 1 part by volume of distilled water and 10 parts by volume of absolute ethyl alcohol, and reacting for 6 hours under the stirring condition; washing with anhydrous ethanol for 3 times, and drying to obtain hydroxylated nanometer silica with average particle diameter of 22 nm.

Step 2: 3g of hydroxylated nano-silica was fully dispersed in 300mL of cyclohexane to obtain a hydroxylated nano-silica stock solution. Then 5g of maleic anhydride was added to the stock solution and stirred at room temperature for 12 hours. Centrifuging for 15min at the rotating speed of 8500 r/min; the same operation is carried out on the upper layer liquid; finally, combining products at the lower layer of the two centrifugations; washed 3 times with absolute ethanol. Vacuum drying to remove residual solvent, and grinding to obtain the surface modified hydrophilic nano silicon dioxide.

And step 3: according to the following formula ratio, the content of the surface modified hydrophilic nano silicon dioxide is 0.1 wt%; the content of sodium lauroyl glucoside hydroxypropyl sulfonate is 0.15 wt%; the content of the alpha-olefin sodium sulfonate is 0.06 wt%; the balance of water; the components are uniformly mixed, and the pH value is adjusted to be 11, so that the nano oil displacement agent is obtained.

Comparative example 1

Step 1, the average particle diameter of 20nm and the specific surface area of 200m are used²Per g of hydrophilic fumed silica, the other conditions being as in example 1.

Comparative example 2

Step 3 sodium lauroyl glucoside hydroxypropyl sulfonate was not added, and the other conditions were the same as in example 1.

Comparative example 3

Step 3 sodium alpha-olefin sulfonate was not added, and the other conditions were the same as in example 1.

Testing of oil displacement performance

The oil displacement performance test was performed on the nano oil-displacing agents of example 1 and comparative examples 1 to 3 according to the oil displacement experimental method of CN108410440A example 8, and the respective nano oil-displacing agent recovery rates (secondary water displacement recovery rate-primary recovery rate) were calculated. See table 1 for results.

TABLE 1

Oil displacement agent	Recovery of oil
		Examples1	27.1％
Comparative example 1	25.8％
		Comparative example 2	19.2％
Comparative example 3	22.5％

As can be seen from Table 1, the oil recovery ratio was higher for the nano oil-displacing agent of inventive example 1 as compared with comparative examples 1-3.

It should be understood that the detailed description of the invention is merely illustrative of the spirit and principles of the invention and is not intended to limit the scope of the invention. Furthermore, it should be understood that various changes, substitutions, deletions, modifications or adjustments may be made by those skilled in the art after reading the disclosure of the present invention, and such equivalents are also within the scope of the invention as defined in the appended claims.

Claims

1. The nano oil displacement agent is characterized by comprising surface-modified hydrophilic nano silicon dioxide, sodium lauroyl glucoside hydroxypropyl sulfonate, sodium alpha-olefin sulfonate and water.

2. The nano oil-displacing agent according to claim 1, wherein the surface-modified hydrophilic nano silica is selected from succinic anhydride or maleic anhydride modified hydrophilic nano silica.

3. The nano oil-displacing agent according to claim 1 or 2, wherein the hydrophilic nano silica is selected from hydroxylated nano silica.

4. The nano oil-displacing agent according to claim 3, wherein the hydroxylated modified silica is prepared by: mixing 2-4 parts by volume of TEOS and 10 parts by volume of absolute ethyl alcohol uniformly, adding the mixture into a mixed solution formed by mixing 0.5-1.5 parts by volume of ammonia water, 0.5-1.5 parts by volume of distilled water and 10 parts by volume of absolute ethyl alcohol, and reacting for 4-8 hours under the condition of stirring to obtain the TEOS.

5. The nano oil-displacing agent according to claim 4, wherein the hydroxylated nano silica has an average diameter of 10-40 nm.

6. The nano oil-displacing agent according to claim 1, wherein the content of the surface-modified hydrophilic nano silica is 0.01-0.8 wt%; preferably 0.05 to 0.2 wt%.

7. The nano oil-displacing agent according to claim 1 or 6, wherein the content of sodium lauroyl glucoside hydroxypropyl sulfonate is 0.05-0.60 wt%; preferably 0.08-0.25 wt%.

8. The nano oil-displacing agent according to claim 1 or 7, wherein the content of sodium alpha-olefin sulfonate is 0.01-0.40 wt%; preferably 0.03 to 0.09 wt%.

9. The nano oil-displacing agent according to claim 1 or 8, wherein the balance is water, and the pH of the nano oil-displacing agent is 10 to 12.

10. A method for preparing the nano oil-displacing agent of any one of claims 1 to 9, comprising: according to the formula ratio, the components are uniformly mixed, and the pH value is adjusted to 10-12, so that the nano oil-displacing agent is obtained.