A nanoscale biomass oil displacement agent based on plant polyphenols and its preparation method

Abstract

This invention discloses a nanoscale biomass oil displacement agent based on plant polyphenols and its preparation method. By mass percentage, the oil displacement agent comprises the following raw materials: 4-8% plant polyphenol (SETA), 1-5% surfactant (BH), 6.5-10.5% auxiliary agent, and 76.5-88.5% water. The auxiliary agent includes glycerol (GLY), urea, and sodium hydroxide (NaOH). This invention's oil displacement agent exhibits good stability. The plant polyphenol used is tannin from the bark of the Brazilian vitex (SETA), which possesses a large number of hydroxyl groups and exhibits amphiphilicity, constituting the components of the oil displacement agent's nanoparticles. It has the advantages of being environmentally friendly, pollution-free, and chemically stable. Compared with traditional oil displacement agents, this invention uses widely available and inexpensive plant polyphenols as raw materials. Furthermore, the preparation process is simple, and it is easy to store and transport. It possesses the advantages of being environmentally friendly, pollution-free, and chemically stable, and can improve oil production while meeting environmental protection requirements and saving costs.

Description

Technical Field

[0001] This invention relates to the field of oil displacement agent technology, and to a method for preparing a biomass oil displacement agent at the smaller than 100nm level and its application, specifically a nanoscale biomass oil displacement agent based on plant polyphenols and its preparation method. Background Technology

[0002] For most oilfields worldwide, at least half of the oil remains in the reservoir after primary (artificial lifting) and secondary (waterflooding) recovery methods. Tertiary oil recovery, also known as enhanced oil recovery (EOR), improves oil recovery by increasing macroscopic sweep efficiency or microscopic displacement efficiency. Chemical flooding, as a successful EOR method, primarily enhances recovery by injecting oil displacement agents such as polymers and surfactants into the geological structure of the well. For example, hydrolyzed polyacrylamide copolymers (FLOPAAM) are used as flocculants to control the migration rate of injected water in EOR. However, polymers are often easily degraded in the formation and retained in the well due to their limited temperature and salt tolerance, while the application of surfactants is limited by their high cost. To address the problems associated with chemical flooding agents, researchers have proposed nano-chemical flooding agents. Nano-chemical flooding agents have a large specific surface area and surface energy, which can significantly reduce the oil-water interfacial tension and increase the contact angle between oil and rock formations, making it easier for crude oil to detach from the rock formation and significantly improving oil recovery. However, nano-chemical oil displacement agents are not suitable for long-term industrial applications due to their complex synthesis process and poor high-temperature and salt resistance. Therefore, it is crucial to develop novel bio-oil displacement agents with good temperature and salt resistance, low cost, and environmental friendliness.

[0003] Bio-based materials have been widely used in biomedicine, agriculture, food, and other fields due to their broad availability, low cost, and environmental friendliness. These materials have the potential for application in oil displacement agents (EOR). For example, cellulose polymers exhibit good emulsification efficiency and can form stable emulsions with oils. However, research on bio-based oil displacement agents for EOR has primarily focused on cellulose, while other bio-based oil displacement agents with specific solubility and excellent emulsification properties also have significant application potential in the EOR field.

[0004] Oils and fats are not only renewable resources, but their unbranched, acyclic, straight-chain fatty acid esters are also excellent raw materials for surfactant production. Oil derivatives and oil-based surfactants made from natural fatty acids exhibit excellent biodegradability and are known as green surfactants. Utilizing abundant oil residues and soapstocks to produce fatty acids and fatty acid methyl esters, and then synthesizing enhanced oil recovery (EOR) agents, not only turns waste into treasure, but also yields products with a specific carbon number distribution, making them more suitable for formulation with alkali polymers than single-component products. This results in EOR agents with superior performance, good biodegradability, low pollution, good safety in use, and low cost.

[0005] For example, an article in the *Acta Petrolei Sinica* titled "Preparation of Alkylamide-type Displacement Agents from Vegetable Oil By-products" describes the development of surfactants for oil displacement using industrial waste—oil residue and soap residue—as raw materials. The preparation conditions and formulation were investigated, and their structure and properties were determined. First, mixed fatty acids were prepared by hydrolyzing oil residue or soap residue, followed by the synthesis of alkylamides. Tests showed that these surfactants significantly reduced the interfacial tension between oil and water and exhibited excellent resistance to salt and high-valence ions, with minimal loss of interfacial activity in hard water. However, while using oil residue and soap residue as raw materials for oil displacement surfactants offers advantages such as turning waste into treasure and being economical and environmentally friendly, the extraction and product synthesis steps are cumbersome and complex, and it is difficult to guarantee the recovery rate of small-pore oilfields in some tight oil reservoirs. Therefore, we need to prepare an oil displacement agent that is both environmentally friendly and can ensure the efficiency of porous oil recovery. Summary of the Invention

[0006] The purpose of this invention is to provide a nanoscale biomass oil displacement agent based on plant polyphenols and its preparation method, so as to solve the problems mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] A nanoscale biomass oil displacement agent based on plant polyphenols and its preparation method, comprising the following raw materials by mass percentage: 4-8% plant polyphenols, 1-5% surfactant (BH), 6.5-10.5% auxiliaries and 76.5-88.5% water.

[0009] As a further aspect of the present invention: the plant polyphenol is tannin from the bark of the Brazilian vitex (SETA).

[0010] As a further aspect of the present invention, the surfactant is isotretinoin (BH).

[0011] As a further embodiment of the present invention, the auxiliary agents include glycerol (GLY), urea (Urea), and sodium hydroxide (NaOH).

[0012] As a further aspect of the present invention, the water is deionized water.

[0013] As a further embodiment of the present invention, the preparation method steps are as follows;

[0014] Step 1: Mix plant polyphenols, surfactants, a series of auxiliary agents, and water;

[0015] Step 2: Further react at room temperature and under magnetic stirring (500 rpm);

[0016] Step 3: Finally, a nanoscale biomass oil displacement agent based on plant polyphenols is obtained.

[0017] As a further embodiment of the present invention: both steps one and two are prepared at room temperature (25°C), and the total reaction time is 2-3 hours.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] 1. The plant polyphenol, Brazilian vitex bark tannin (SETA), used in this invention is extracted from plants and has a large number of hydroxyl groups, making it amphiphilic and constituting a component of oil-displacing nanoparticles;

[0020] 2. The surfactant used in this invention is tridecyl alcohol (BH), which is extracted from plants and has the functions of reducing interfacial tension and improving the salt resistance and stability of nanoparticles.

[0021] 3. Among the series of auxiliary agents used in this invention, glycerol can promote the dissolution of SETA and form particles with a particle size distribution of about 100 nm; urea can improve the small size stability of the oil displacement agent; sodium hydroxide can adjust the appropriate pH to make the nanoparticle size more stable, so that the obtained DLS data are concentrated at about 100 nm.

[0022] 4. Compared with traditional oil displacement agents, this invention uses widely available and inexpensive plant polyphenols as raw materials. Moreover, the preparation process is simple, easy to store and transport, and has the advantages of being environmentally friendly, pollution-free, and having a stable chemical structure. It can improve oil production while meeting environmental protection requirements and saving costs. Attached Figure Description

[0023] Figure 1 This is a process diagram for preparing a nanoscale biomass oil displacement agent based on plant polyphenols.

[0024] Figure 2 This invention discloses an ultra-low interfacial tension meter for testing the interfacial tension of the oil displacement agent of the present invention, as an embodiment of the present invention.

[0025] Figure 3This is a Tyndall effect diagram of the oil displacement agent working fluid and water disclosed in one embodiment of the present invention.

[0026] Figure 4 This is a diagram illustrating the oil-washing effect of the oil displacement agent working fluid and water in one embodiment of the present invention.

[0027] Figure 5 This is a particle size test diagram of the oil displacement agent working fluid of the present invention, as disclosed in one embodiment of the present invention.

[0028] Figure 6 This is a scanning electron microscope image of the oil displacement agent working fluid of the present invention, as disclosed in one embodiment of the present invention.

[0029] Figure 7 This is a test diagram of the contact angle between the working fluid of the oil displacement agent of the present invention and water, as disclosed in one embodiment of the present invention.

[0030] Figure 8 This is a table showing the interfacial tension test results of the working fluid of the oil displacement agent of the present invention, as disclosed in one embodiment of the present invention.

[0031] Figure 9 This is a graph showing the interfacial tension between the working fluid of the oil displacement agent of this invention and white oil. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figures 1-9 This invention provides a nano-scale biomass oil displacement agent based on plant polyphenols and its preparation method. The preparation method mainly focuses on using Brazilian vitex bark tannin (SETA) as the basic raw material, isotridecyl alcohol (BH) as the surfactant, and glycerol (GLY), urea, and sodium hydroxide (NaOH) as auxiliary agents. The prepared nano-scale biomass oil displacement agent is applied to oilfield oil displacement using the following steps:

[0034] 4-8% plant polyphenols, 1-5% surfactant (BH), 6.5-10.5% auxiliaries and 76.5-88.5% water were mixed and reacted at room temperature (25℃) and under magnetic stirring (500 rpm) for 2-3 hours to obtain a nano-scale biomass oil displacement agent based on plant polyphenols.

[0035] Furthermore, the oil displacement agent was further tested to verify its oil displacement effect, including its oil washing effect and interfacial tension test.

[0036] This preparation method is convenient to operate and has a simple process. The prepared nanoscale bio-enhanced oil recovery agent has good stability, is environmentally friendly, and can ensure the efficiency of pore oil recovery, thereby improving oil production to a certain extent. Figure 4 As shown, Figure 4 The diagram shows the oil washing effect of the oil displacement agent working fluid and water. Figure 4 It can be seen that the prepared oil displacement agent has a strong ability to clean the bottle wall, indicating a certain emulsifying effect on crude oil C#, which macroscopically confirms the oil displacement effect of the nano-oil displacement agent. Furthermore, as... Figure 8-9 As shown, Figure 8-9 The interfacial tension test results for the working fluid of the oil displacement agent show that the lowest interfacial tension of this oil displacement agent reaches 0.01 mN / m, which is 10. -2 At the mN / m level, it can reduce the interfacial tension between oil and water to a certain extent.

[0037] In this embodiment of the invention, a nanoscale biomass oil displacement agent based on plant polyphenols and its preparation method are disclosed. The agent comprises, by mass percentage, the following raw materials: 4-8% plant polyphenols, 1-5% surfactant (BH), 6.5-10.5% auxiliaries, and 76.5-88.5% water. The plant polyphenol is tannin from the bark of the Brazilian vitex (SETA), extracted from plants. Due to its abundant hydroxyl groups, it exhibits amphiphilicity and is a component of the oil displacement agent nanoparticles. The surfactant is tridecyl isomeric alcohol (BH), which is easily dispersed or soluble in water, possesses excellent wetting, penetrating, and emulsifying properties, and has the function of reducing interfacial tension and improving the salt resistance and stability of the nanoparticles. The auxiliaries include glycerol (GLY), urea, sodium hydroxide (NaOH), etc. The water is deionized water.

[0038] The preparation method steps are as follows;

[0039] Step 1: Mix plant polyphenols, surfactants, a series of auxiliary agents, and water;

[0040] Step 2: Further react under the conditions of room temperature (25°C) and magnetic stirring (500 rpm);

[0041] Step 3: Finally, a nanoscale biomass oil displacement agent based on plant polyphenols is obtained.

[0042] Both steps one and two are prepared at room temperature (25°C), and the total reaction time is 2-3 hours.

[0043] Example 1

[0044] This embodiment provides a nanoscale biomass oil displacement agent based on plant polyphenols, which is composed of the following percentage components: 6% plant polyphenols, 3% surfactant (BH), 8.5% auxiliary agent, and 82.5% water;

[0045] This embodiment also provides a method for preparing the above-mentioned oil displacement agent, including the following steps:

[0046] S1: First, mix 50% water and 6% glycerol (GLY) in the total sample and stir for 30 minutes;

[0047] S2: Further add 6% plant polyphenols (SETA) to the reaction system, then add 2.5% urea (Urea). During the addition process, add the remaining water while stirring continuously for 30 minutes.

[0048] S3: Add 0.125% NaOH solution and test with pH paper until the solution is weakly alkaline. Stir at room temperature for 1 hour.

[0049] S4: Finally, add 3% isotridecyl alcohol (BH), mix and stir for 30 minutes to obtain a nano-scale biomass oil displacement agent based on plant polyphenols.

[0050] The oil displacement agent of this invention exhibits good solubility after oscillation and sonication, and can be left to stand for a certain period of time, indicating that the solid content is appropriate and the sample has a certain degree of stability.

[0051] Example 2

[0052] This embodiment provides a nanoscale biomass oil displacement agent based on plant polyphenols, which is composed of the following percentage components: 4% plant polyphenols; 1% surfactant (BH); 6.5% auxiliary agent; and 88.5% water.

[0053] The preparation method of the oil displacement agent in this embodiment is the same as in Embodiment 1.

[0054] Example 3

[0055] This embodiment provides a nanoscale biomass oil displacement agent based on plant polyphenols, which is composed of the following percentage components: 8% plant polyphenols; 5% surfactant (BH); 10.5% auxiliary agent; and 76.5% water.

[0056] The preparation method of the oil displacement agent in this embodiment is the same as in Embodiment 1.

[0057] Experimental Example

[0058] This experimental example tests the structure and performance of the oil displacement agent in Example 1, as follows:

[0059] Step 1: The crude oil size was tested using the oil displacement agent prepared in Example 1, mainly including the following three processes: A small amount of the oil displacement agent was taken, diluted 3 / 1000, and the Tyndall effect was checked using a laser pointer; the DLS particle size was tested using a Nano ZSP particle size analyzer; and the morphology and particle size distribution of the oil displacement agent were analyzed using scanning electron microscopy. Figure 3 As can be seen, compared with water, the prepared nanoscale biomass oil displacement agent, when illuminated with a laser pointer in a dark environment, shows no bright path in water, while the oil displacement agent clearly shows a bright path, indicating that it exhibits the Tyndall effect, thus simply proving that it is at the nanoscale. The particle size of the oil displacement agent sample was further tested using a particle size analyzer, as shown in the attached figure. Figure 4 As shown, the particle size of this nano-scale biomass oil displacement agent is approximately 100 nm, and it is composed of... Figure 5 Further testing of the morphology and particle size distribution of the oil displacement agent samples using scanning electron microscopy revealed that the samples were all granular with a particle size distribution of less than 100 nm.

[0060] Step 2: Crude oil emulsification test was conducted using the oil displacement agent prepared in Example 1;

[0061] The steps are as follows: A small amount of crude oil is evenly coated onto the wall of a centrifuge tube. The oil displacement agent prepared in Example 1 of this invention is used to conduct a crude oil emulsification test. The mixture is stirred at a certain volume ratio, and the tube is inverted multiple times to obtain an emulsion of the oil displacement agent and oil. The oil washing effect of the sample oil displacement agent is observed. Figure 5 As can be seen, compared with the water sample, the oil displacement agent prepared in Example 1 of this invention has a strong ability to clean the bottle wall, indicating that it has a certain emulsifying effect on crude oil, which macroscopically confirms the oil displacement effect of the sample.

[0062] Step 3: The contact angle of the oil displacement agent prepared in Example 1 was tested;

[0063] The steps are as follows: Apply crude oil to two clean glass plates respectively. Use a contact angle tester to slowly add water and oil-removing agent to the two glass plates respectively, and observe the contact angle. (See attached image) Figure 7 The contact angles between water and oil and between the sample oil displacement agent and oil were measured using a contact angle tester. It was found that the sample oil displacement agent has good hydrophilicity, which can significantly reduce the contact angle, improve wettability, and reduce surface tension to a certain extent.

[0064] Step 4: The interfacial tension of the oil displacement agent prepared in Example 1 was tested;

[0065] The instrument uses an attached Figure 2 The TX-500C interfacial tensiometer was used in the test at 25℃, and the density difference between the oil displacement agent and the crude oil was 0.2255 g / cm³. 3 The interfacial tension between oil and water was measured at a speed of 5000 rad / min. The experimental results are as follows: Figure 8-9As shown, the minimum interfacial tension of this oil displacement agent reaches 0.01 mN / m, which is 10. -2 At the mN / m level, it can reduce the interfacial tension between oil and water to a certain extent.

[0066] As can be seen from the above embodiments, the present invention provides a nano-scale biomass oil displacement agent with plant polyphenols as the basic raw material, which contains the following raw materials by mass percentage: 4-8% plant polyphenols, 1-5% surfactant (BH), 6.5-10.5% auxiliary agent and 76.5-88.5% water.

[0067] Through various tests of the embodiments of the present invention, the oil displacement agent of the present invention can meet the requirements of pore oil recovery and oil displacement agents that are economical, environmentally friendly and low-carbon, providing a new sustainable development approach for improving oil recovery.

[0068] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A nanoscale biomass oil displacement agent based on plant polyphenols, characterized in that: The product contains the following raw materials by mass percentage: 4-8% plant polyphenols, 1-5% surfactants, 6.5-10.5% auxiliaries and 76.5-88.5% water. The plant polyphenols are tannins from the bark of the Brazilian chamomile tree, the surfactants are isotridecyl alcohol, and the auxiliaries include glycerol, urea and sodium hydroxide.

2. The nanoscale biomass oil displacement agent based on plant polyphenols according to claim 1, characterized in that: The water is deionized water.

3. The method for preparing nanoscale biomass oil displacement agent based on plant polyphenols according to claim 1, characterized in that: The preparation method steps are as follows; Step 1: Mix plant polyphenols, surfactants, additives, and water; Step 2: Further reaction under room temperature and magnetic stirring conditions; Step 3: Finally, a nanoscale biomass oil displacement agent based on plant polyphenols is obtained.

4. The method for preparing nanoscale biomass oil displacement agent based on plant polyphenols according to claim 3, characterized in that: Both steps one and two are prepared at room temperature, and the total reaction time is 2-3 h.

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