CN113185657A

CN113185657A - Nano material and preparation method and application thereof

Info

Publication number: CN113185657A
Application number: CN202110346623.4A
Authority: CN
Inventors: 邓青春; 刘艳华; 吴向阳; 方叶青; 史建民; 王耀国
Original assignee: Ningbo Fengcheng Advanced Energy Materials Research Institute Co Ltd
Current assignee: Ningbo Fengcheng Advanced Energy Materials Research Institute Co Ltd
Priority date: 2021-03-31
Filing date: 2021-03-31
Publication date: 2021-07-30
Anticipated expiration: 2041-03-31
Also published as: CN113185657B

Abstract

The application discloses a nano material, which is prepared by carrying out polymerization reaction on a mixture containing coupling montmorillonite, an organic hydrophobic monomer, an organic hydrophilic monomer and an initiator. The nano material has good long-term stability, low interfacial tension and enhanced recovery efficiency.

Description

Nano material and preparation method and application thereof

Technical Field

The application relates to a nano material and a preparation method and application thereof, belonging to the field of viscosity reduction of thick oil.

Background

The demand of petroleum in China continuously increases, the dependence of petroleum on the exterior continuously increases, the dependence of the country on the exterior reaches 72 percent in 2019, is 22 percent higher than the international alert, and becomes the largest crude oil import country in the world. At present, the global average recovery rate is 35 percent, the average recovery rate in China is 30 percent, only one third of 100 hundred million tons with good quality can be produced, and 90 percent of the poor quality is remained underground. World oil prices are constantly changing, but low cost efficient production of oil and gas and increasing production reserves are constant pursuits.

Most oil fields developed in China enter the middle and later stages of development, the contradiction of the supply and demand relationship of petroleum is aggravated, and the increase of the yield and the efficiency of the petroleum yield are urgently required by the energy storage and the market demand. With the development of oil exploration technology and the demand of national strategic energy, the development of low-permeability and ultra-low permeability oil fields will be important battlefields meeting the requirements in the next years or decades.

The development history of the hypotonic oil field in China is long, the first oil well on land, namely the prolonged oil field No. 1 well, is an ultra-hypotonic oil layer, the gas logging permeability is only 0.3mD, the porosity is 8 percent, and the initial daily yield is only about 1.5 t. At present, China successfully develops a plurality of low-permeability and ultra-low-permeability oil fields, and the low-permeability geological reserves are widely distributed in large oil areas in the middle and western parts of Daqing, Changqing, Xinjiang and the like. In order to keep the continuous and stable development of the petroleum industry in China, the unused low-permeability reserves need to be effectively put into development, and the developed low-permeability reserves need to be improved in development effect.

At present, the following measures are mainly adopted in the aspect of improving the recovery ratio of low-permeability oil reservoirs at home and abroad: the method comprises the following steps of well pattern encryption, horizontal well exploitation, fine separated layer water injection, fracture acidizing, microbial oil recovery, gas injection development and surfactant flooding. The first 4 techniques are mainly used for increasing the macroscopic swept volume, and the last 3 techniques are mainly used for improving the microscopic oil washing efficiency. Then, the technologies have advantages and disadvantages, and have the problems of increasing oil extraction cost, high stratum adaptability, reducing oil layer productivity, difficult control of manufacturing cracks, high environmental requirements, difficult searching of gas sources and the like, and the surfactant flooding also has the problems of economic cost to a certain degree and migration loss of the surfactant in geological pore canals of the reservoir.

Nanotechnology is a new technology with attention introduced in the 21 st century, and the application of nanotechnology in the field of oil fields has already received wide attention of many experts and scholars. The specific 'nano effect' of the nano material can play a role in nano gain in oil field chemicals, or improve the interfacial activity of a surfactant, or form 'wedge pressure', or stabilize foam, or reduce the using amount of the oil field chemicals so as to reduce the cost, and the like.

Disclosure of Invention

According to one aspect of the application, the nano material is prepared by carrying out polymerization reaction on a mixture containing coupling montmorillonite, an organic hydrophobic monomer, an organic hydrophilic monomer and an initiator, and can improve the interfacial activity of a surfactant and reduce the oil-water interfacial tension by compounding the nano material with the surfactant for oil displacement.

The application provides a nano material used in a low-permeability oil field, which shows a gain effect after synergistic action with a surfactant to obtain a nano oil displacement agent. The nano material has good long-term stability, low interfacial tension and enhanced recovery efficiency.

According to a first aspect of the application, a nano material is provided, which is prepared by carrying out polymerization reaction on a mixture containing coupling montmorillonite, an organic hydrophobic monomer, an organic hydrophilic monomer and an initiator;

the organic hydrophobic monomer is selected from at least one of alpha-sodium alkenyl sulfonate, sodium dodecyl allyl sulfonate, sodium tetradecyl allyl sulfonate and ammonium tetradecyl allyl chloride;

the organic hydrophilic monomer is selected from a compound A and a compound B;

the compound A is selected from at least one of acrylamide, acrylic acid and sodium acrylate;

the compound B is at least one selected from maleic anhydride, vinyl ester maleic anhydride and styrene maleic anhydride.

Optionally, the nanomaterial has an interfacial tension of 10^-1～10^-2mN/m。

According to a second aspect of the present application, there is provided a method for preparing the above-mentioned nanomaterial, the method comprising:

and carrying out polymerization reaction on a mixture containing the coupling montmorillonite, the organic hydrophobic monomer, the compound A, the compound B and the initiator to obtain the nano material.

Optionally, the initiator is selected from at least one of potassium persulfate, ammonium persulfate, and sodium persulfate.

Alternatively, the conditions of the polymerization reaction are: the temperature is 75-85 ℃; the time is 3-5 h.

Optionally, the mass ratio of the coupled montmorillonite to the organic hydrophobic monomer to the compound a to the compound B to the initiator is 1: 0.5-1.5: 0.5-1.5: 0.6-2: 0.008-0.025.

Optionally, the method comprises:

(1) dissolving raw materials containing coupling montmorillonite, organic hydrophobic monomer, compound A and compound B in water, and deoxidizing to obtain a mixture I;

(2) dissolving a material containing an initiator in water, and deoxidizing to obtain a mixture II;

(3) and dropwise adding the mixture II into the mixture I, and carrying out polymerization reaction to obtain the nano material.

Optionally, in the mixture II, the mass ratio of the initiator to the water is 0.1 to 1: 100, respectively;

in the step (3), the mixture II is added dropwise into the mixture I within 7-10 min.

Alternatively, the polymerization reaction was carried out after stirring at 55 ℃ for 30 min.

According to a third aspect of the application, an oil displacement agent is provided, wherein the oil displacement agent comprises at least one of the nano material and the nano material prepared by the method.

Optionally, the oil displacement agent further comprises a surfactant;

the surfactant is selected from sulfate type surfactants.

Optionally, the surfactant is selected from 7003.

Optionally, in the oil displacement agent, the mass ratio of the surfactant to the nano material is 2-4: 1-2.

Preferably, in the oil displacement agent, the mass ratio of the surfactant to the nano material is 2:1 to 2.

According to a fourth aspect of the application, a preparation method of the oil displacement agent is provided, wherein the method comprises the following steps:

and mixing the surfactant and the nano material to obtain the oil displacement agent.

Optionally, the method comprises: and mixing the solution i containing the surfactant and the solution ii containing the nano material to obtain the oil displacement agent.

Optionally, in the solution i, the mass content of the surfactant is 20-40%;

in the solution ii, the mass content of the nano material is 10-20%.

According to a final aspect of the application, the application of at least one of the oil displacement agent and the oil displacement agent prepared by the method in low permeability oil fields is provided.

The interface tension of the nano material provided by the application is lower than that of a single surfactant under the oil reservoir conditions of the Changqing crude oil and the Changqing block, and the interface activity gain effect of the nano material is embodied.

The nano material has the effect of improving the recovery ratio higher than that of a surfactant under the oil reservoir conditions of the Changqing crude oil and the Changqing blocks, the recovery ratio of the nano material is improved by 17 percent, and the recovery ratio of the nano material is improved by 11 percent, which can be caused by the following reasons: first, low interfacial tension of DSN systems; second, DSN systems lose little during reservoir migration.

The beneficial effects that this application can produce include:

1. the nano material is synthesized, and can improve the interfacial activity of the surfactant and reduce the oil-water interfacial tension by being compounded with the surfactant for oil displacement.

2. Through a multifunctional displacement instrument displacement experiment, the nano oil displacement agent formed by a compounding system of the nano material and the surfactant can obviously improve the recovery ratio.

3. The adsorption of the oil displacement agent can be obviously reduced through the synergistic effect of the nano materials; and the loss amount of the surfactant under the condition of simulating the stratum is reduced.

4. The cost is relatively low, and a good nano gain effect exists; meanwhile, the oil-water-based oil-water well has small particle size, low interfacial tension and enhanced oil recovery effect.

Drawings

Figure 1 is a graph of interfacial tension of surfactant 7003 at different concentrations;

FIG. 2 is a graph of interfacial tension of the oil-displacing agent prepared in example 4 at different concentrations;

FIG. 3 is a displacement test chart of approximately 20mD gas permeability measured by DSN of the oil displacement agent prepared in example 4;

FIG. 4 is a displacement test chart of surfactant 7003 gas permeability of about 20 mD.

Detailed Description

The present application will be described in detail with reference to examples, but the present application is not limited to these examples.

The raw materials in the examples of the present application were all purchased commercially, unless otherwise specified. If not stated, the test method adopts the conventional method, and the instrument setting adopts the setting recommended by the manufacturer.

The coupling montmorillonite used in the embodiment of the application is purchased from Zhejiang Fenghong at 30-100 nm.

The surfactants 7001,7002,7003 used in the examples of this application are all available from Nipponfo Nth nanotechnology Co.

EXAMPLE 1 preparation of nanomaterial # 1

1. Weighing 15g of monomer AOS (alpha-olefin sodium sulfonate), 15g of monomer acrylamide, 20g of monomer maleic anhydride organic hydrophilic monomer and 10g of coupling montmorillonite into a three-neck flask, adding 900g of deionized water, stirring and dissolving, introducing nitrogen for 30min, and removing oxygen in the solution;

2. weighing 0.25g of initiator potassium persulfate, adding 50g of deionized water, stirring for dissolving, introducing nitrogen for 30min, and removing oxygen (initiator concentration is 0.5 wt%) in the solution;

mechanically stirring the solution in the step 1 at 3.250rpm, starting heating, and setting the heating temperature to be 55 ℃;

4. and (3) dropwise adding potassium persulfate in the solution 2 by using a constant-pressure funnel when the temperature of the solution in the flask reaches 45 ℃, simultaneously setting the reaction temperature to 80 ℃, finishing dropping the initiator after 7-10min, starting timing when the temperature of the reaction solution reaches 80 ℃, and finishing the reaction after 3h of reaction.

Example 2 preparation of nanomaterial 2#

1. Weighing 15g of monomer AOS (alpha-olefin sodium sulfonate), 15g of monomer acrylamide, 20g of monomer maleic anhydride organic hydrophilic monomer and 20g of coupling montmorillonite into a three-neck flask, adding 900g of deionized water, stirring and dissolving, introducing nitrogen for 30min, and removing oxygen in the solution;

Example 3 preparation of nanomaterial # 3

1. Weighing 15g of monomer AOS (alpha-olefin sodium sulfonate), 15g of monomer acrylamide, 20g of monomer maleic anhydride organic hydrophilic monomer and 30g of coupling montmorillonite into a three-neck flask, adding 900g of deionized water, stirring for dissolving, introducing nitrogen for 30min, and removing oxygen in the solution;

Example 4 preparation of oil-displacing agent 1

Adding 20 wt% of 7003 solution (solvent is water) into 10 wt% of PMS solution (solvent is water) prepared in example 1 according to the mass ratio of 1:1, and stirring for 30min at 50 ℃ until the solution is uniformly mixed without obvious layering, thus obtaining the oil displacement agent 1.

Example 5 preparation of oil-displacing agent 2

Adding 20 wt% of 7003 solution (solvent is water) into 10 wt% of PMS solution (solvent is water) prepared in example 1 according to the mass ratio of 1:2, and stirring for 30min at 50 ℃ until the solution is uniformly mixed without obvious layering, thus obtaining the oil displacement agent 2.

Example 6 preparation of oil-displacing agent 3

Adding 20 wt% of 7003 solution (solvent is water) into 10 wt% of PMS solution (solvent is water) obtained in example 1 according to the mass ratio of 2:1, and stirring for 30min at 50 ℃ until the solution is uniformly mixed without obvious layering, thus obtaining the oil-displacing agent 3.

Example 7

The nanomaterials prepared in examples 1 to 3 were diluted with water to adjust their concentrations to the corresponding desired concentrations, and the interfacial tension values in simulated formation water and 6 ten thousand salinity water were tested, and the specific data are shown in table 1 below.

TABLE 1

As can be seen from Table 1 above, the 1# and 2# nanomaterials had lower interfacial tensions at 10 for the Changqing crude oil (the Changqing crude oil was provided by 6 Changqing oil extraction plants and was used as the Hao midblock oil in the Changqing oil field)^-1mN/m; for detecting 6 ten thousand mineralization degree waterAt the tension, the interfacial tension of 1# and 2# (using concentration of 1000ppm) was still 10^-1mN/m。

Example 8

According to the actual requirements of an oil field site, the surfactant is an essential product in the oil field; 7001,7002,7003 is a surfactant prepared by Ningbo advanced energy materials research institute, as can be seen from the following Table 2, the 7001 particle size is 416nm under 6 ten thousand mineralization degree, and the interfacial tension is 0.05 mN/m; 7003 the particle diameter is 340nm, the interfacial tension is 0.01 mN/m; 7002 the grain size is 6000nm, and the grain size is too large to be applied to low-permeability oil fields. Secondly, after three materials of PMS series are compounded with 7001 and 7003 surfactants (the compounding method is that PMS solution (the concentration is 1000ppm) and 7003 solution (the concentration is 2000ppm) are mixed according to the mass ratio of 1: 1), the interfacial tension data of the obtained compounded materials are shown in the following table, and as can be seen from the table, only 7003 has a gain effect, the interfacial tension is reduced by one order of magnitude and is reduced to 0.008mN/m, and the particle size is not changed greatly.

Therefore, the performance tests of the following examples were carried out on a nano oil displacement agent DSN for a low permeability oilfield formed by compounding PMS-2 (using concentration of 1000ppm) and 7003 (using concentration of 2000 ppm).

TABLE 2

Example 9 Long-term stability of oil-displacing agent DSN

The oil-displacing agent sample prepared in example 4 was diluted with 6 ten thousand of mineralization water to a concentration of 2000ppm, placed in a 60 ℃ oven, and continuously followed to observe changes in particle size and interfacial tension. From table 3 below, we can see that after 35 days of continuous observation, the DSN samples had almost no change in interfacial tension and particle size and were still useful for flooding.

TABLE 3

Example 10 oil-displacing agent DSN adsorption Performance test

Adsorption experiments under reservoir conditions were tested with DSNs (prepared in example 4) and 7003 diluted to 2000ppm with 6 million mineralization water.

Experimental procedure

(1) Drawing a standard curve between interfacial tension and surfactant concentration: and (3) diluting the DSN and 7003 to different times by using mineralized water, testing specific values of the oil-water interfacial tension under different dilution times (the rotation time of an interfacial tension meter is fixed at 5min, and recording the interfacial tension value when the time is up), and drawing a standard curve of the DSN and 7003 according to the tested interfacial tension value and the corresponding use concentration. The standard curve is shown in fig. 1 and 2:

(2) injecting water (the mineralization degree of the mineralized water is 6 million, which is matched with the field condition and corresponds to the mineralization degree of the whole experiment) into a target block to prepare 90g of surfactant solution, stirring the surfactant solution on a magnetic stirrer for 15min at the rotating speed of (300 +/-20) r/min, mixing the surfactant solution with 30g of simulated formation sand, and placing the mixture into a constant-temperature water bath (the oil reservoir temperature is 170r/min) to oscillate for 24 h.

b. Taking the supernatant of the sample, testing the concentration of the surfactant in the sample, and calculating the static adsorption loss according to the following formula:

in the formula:

x-static adsorption loss, mg/g sand;

C₁-surface active agent concentration,%, before adsorption;

C₂-post-adsorption surfactant concentration,%;

G₁-the mass of the surfactant solution taken, g;

G₂-mass of oil sand taken, g.

Surfactant concentration test method: a standard curve of interfacial tension versus concentration is first prepared. The solution surface tension is measured after adsorption equilibration and its concentration value is read from the standard curve (since many properties of surfactant solutions have a sudden change at CMC, it can only be measured after dilution when the adsorption equilibration concentration exceeds CMC).

The preparation method of the simulated formation sand comprises the following steps:

calculating according to the formula; the adsorption capacity of DSN is 65mg/g sand, while that of 7003 is 600mg/g sand, and the adsorption capacity of DSN is far less than that of 7003 surfactant; the oil displacement agent requires less loss of chemical agent in the reservoir migration process, so that the cost can be reduced.

Example 11 Displacement experiment

A displacement experiment of the raw material 7003 was performed under the same conditions, and the DSN material properties were determined by comparing the effect of the DSN (the DSN prepared in example 8) and the raw material 7003 on the core displacement experiment.

Conditions of the experiment

(1) Water for experiment: the simulated mineralized water has a total mineralization of 60000mg/L and a water type of CaCl 2.

(2) Experimental oil: the white oil is added into the dehydrated Changqing site crude oil for compounding, and the viscosity of the underground crude oil is 87.2mPa.s (55 ℃).

(3) The performance test of the injection system, surface active and nano material, is shown in the following table 4.

TABLE 4

Experimental procedure

(1) Weighing dry weight of the dried core, weighing wet weight after vacuumizing and saturating simulation water, and calculating pore volume;

(2) water permeability (not performed this time): injecting water at the speed of 0.5mL/min, and calculating the permeability of the rock core water after the injection pressure is stable;

(3) saturated oil: placing the core in a 55 ℃ drying oven to saturate crude oil until the produced liquid does not contain water, recording the produced water amount, and calculating the oil saturation;

(4) water flooding: performing water flooding at the speed of 0.1mL/min, recording the liquid production amount, the water production amount, the oil production amount and the pressure at intervals, and displacing until the comprehensive water content reaches 98%;

(5) agent flooding: preparing a flooding agent 0.8PV at the speed of 0.1mL/min, and recording the liquid yield, the water yield, the oil yield and the pressure at intervals;

(6) and (3) subsequent water flooding: performing water flooding at the speed of 0.1mL/min, recording the liquid production amount, the water production amount, the oil production amount and the pressure at intervals, and displacing until the comprehensive water content reaches 98%;

results and analysis

TABLE 5 introduction of basic parameters of experimental core

TABLE 6 pressure Change during Displacement experiment

TABLE 7 enhanced oil recovery data sheet

FIG. 3 is a displacement test chart of approximately 20mD gas permeability measured by DSN of the oil displacement agent prepared in example 4; FIG. 4 is a displacement test chart of surfactant 7003 gas permeability of about 20 mD.

Although the present application has been described with reference to a few embodiments, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the application as defined by the appended claims.

Claims

1. A nanometer material is characterized in that the nanometer material is prepared by the polymerization reaction of a mixture containing coupling montmorillonite, an organic hydrophobic monomer, an organic hydrophilic monomer and an initiator;

the organic hydrophilic monomer is selected from a compound A and a compound B;

2. The nanomaterial of claim 1, wherein the nanomaterial has an interfacial tension of 10^-1～10^- ²mN/m。

3. A method for preparing nanomaterials of claim 1 or 2, wherein the method comprises:

4. The production method according to claim 3, wherein the initiator is at least one selected from the group consisting of potassium persulfate, ammonium persulfate, and sodium persulfate;

preferably, the polymerization conditions are: the temperature is 75-85 ℃; the time is 3-5 h;

preferably, the mass ratio of the coupled montmorillonite, the organic hydrophobic monomer, the compound A, the compound B and the initiator is 1: 0.5-1.5: 0.5-1.5: 0.6-2: 0.008-0.025;

preferably, the method comprises:

(3) dropwise adding the mixture II into the mixture I, and carrying out polymerization reaction to obtain the nano material;

preferably, in the mixture II, the mass ratio of the initiator to the water is 0.1-1: 100, respectively;

5. An oil-displacing agent, wherein the oil-displacing agent comprises at least one of the nanomaterial of claim 1 or 2 and the nanomaterial prepared by the method of claim 3 or 4.

6. The oil-displacing agent according to claim 5, wherein the oil-displacing agent further comprises a surfactant;

the surfactant is selected from sulfate type surfactants;

preferably, in the oil displacement agent, the mass ratio of the surfactant to the nano material is 2-4: 1-2.

7. A method for preparing an oil-displacing agent according to claim 5 or 6, comprising:

8. The method of manufacturing according to claim 7, comprising: and mixing the solution i containing the surfactant and the solution ii containing the nano material to obtain the oil displacement agent.

9. The preparation method according to claim 8, wherein the surfactant is contained in the solution i in an amount of 20 to 40% by mass;

in the solution ii, the mass content of the nano material is 10-20%.

10. Use of at least one of the oil-displacing agent of claim 5 or 6, the oil-displacing agent prepared according to the process of any one of claims 7 to 9 in low permeability oil fields.