High-entropy catalytic emulsion viscosity reducing system and viscosity reducing method

Abstract

The application discloses a high-entropy catalytic emulsion viscosity reducing system and a viscosity reducing method. The high-entropy catalytic emulsion viscosity reducing system is an emulsion viscosity reducing system with an HLB value of 7-14 obtained by mixing high-entropy oxides and an oxidant after being adjusted by a surfactant, wherein the oxidant is an organic peroxide. The emulsion viscosity reducing system is mixed with thick oil and heated to a catalytic reaction temperature for reaction, and the viscosity reduction of the thick oil is completed after the reaction. The high-entropy oxides are compounded with the organic peroxide type oxidant to form a catalytic oxidation-emulsion composite viscosity reducing system in the form of oil-in-water. In the oil reservoir environment (50-180 DEG C), the transition metal catalytic activity is used to break the chemical bonds of the heteroatom side chains of the thick oil, the oxidant is used to cap the thick oil to form oxidized thick oil, and the surfactant contained in the system is used for emulsification again, so that the purpose of the viscosity reduction of the thick oil is achieved, and the viscosity reduction efficiency is further improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of crude oil viscosity reduction, and relates to a catalytic viscosity reduction technology for crude oil, in particular to a high-entropy catalytic emulsion viscosity reduction system and a viscosity reduction method. BACKGROUND

[0002] Thick oil generally refers to crude oil with high asphaltene and resin content, high density and high viscosity, and is a complex mixture of complex hydrocarbons composed of alkanes, aromatic hydrocarbons, resins and asphaltene. Among them, resins and asphaltene are high molecular weight components, containing metals and non-metals such as sulfur, nitrogen, oxygen and other heteroatoms, and asphaltene is the most complex structure, the largest relative molecular weight and the largest relative density component in crude oil. High viscosity and high density are its main characteristics, which are also the main indicators that distinguish thick oil from ordinary light crude oil. Its viscosity is sensitive to temperature, and the viscosity decreases sharply with the increase of temperature. For deep and shallow thick oil, there is a common problem of high viscosity and poor flowability. Understanding the mechanism of thick oil viscosity is the key to solving the problem. According to the analysis, the two components of resin and asphaltene contribute most to the viscosity. Resin contains condensed ring systems composed of thick oil, alicyclic and side chains, and contains nitrogen, sulfur, oxygen and other heteroatoms. Asphaltene is a complex mixture composed of various condensed ring aromatic hydrocarbons, naphthenes, paraffins and metals, non-metals, with high heteroatom content and low hydrogen-carbon atomic ratio. Among them, asphaltene is the key factor of thick oil viscosity. The structure of asphaltene is related to the content of metal and heteroatom, the size of intermolecular force and the relative molecular mass. Through previous exploration, catalytic oxidation technology can be used to reduce the content of heteroatoms and weaken the intermolecular force through catalytic reaction, which is conducive to reducing the viscosity of thick oil.

[0003] High-entropy oxide (HEO) is a new type of material prepared by mixing several metal salts and performing solution combustion reaction at a certain temperature. As a new material, high-entropy oxide contains equal atomic ratio of multiple components (usually ≥5), and has four inherent characteristics of entropy effect, lattice distortion effect, slow diffusion effect and cocktail effect. Due to the random / uniform mixing of five or more components, they have new characteristics. HEO has been proved to have a wide range of significant mechanical properties, dielectric properties and superconducting properties. The research progress of synthesis and catalytic application of high-entropy oxide (You Zijuan et al., Materials Review, 2023, 37(24): 22090127) introduces various synthesis methods and uses of high-entropy oxide, mainly for application in thermal catalysis, electrocatalysis and photocatalysis. In thermal catalysis, such as carbon monoxide oxidation, carbon dioxide hydrogenation, desulfurization, methane and VOCs catalytic oxidation, it has good performance. However, no one has tried to use high-entropy oxide for crude oil viscosity reduction, so related research may lead to new viscosity reduction catalysts, greatly expanding the use of high-entropy oxide. SUMMARY

[0004] The purpose of the present application is to develop a high-entropy catalytic emulsion viscosity reduction system to solve the above technical problems, which uses surfactants to adjust the HLB value of high-entropy oxides and oxidants to form a thick oil catalytic viscosity reduction system, wherein the oxidant is an organic peroxide, and the high-entropy oxide improves the catalytic efficiency. The present application combines catalytic oxidation technology with emulsion viscosity reduction technology. First, the principle of catalytic oxidation viscosity reduction is used to make the polycyclic aromatic hydrocarbon macromolecules in the resin and asphaltene molecules in the thick oil undergo oxidation reaction under the action of the high-entropy oxide catalyst, break the heteroatom side chain, and use active oxygen substances (active oxygen decomposed from the oxidant) to cap, forming organic molecules containing alcohol groups, carbonyl groups and carboxyl groups with dispersity. With the help of these organic molecules with dispersity, the surfactants contained in the system are used for emulsification again, so that the sequence of catalysis and emulsification occurs, and the viscosity of the thick oil is reduced.

[0005] In one aspect, the present application provides a high-entropy catalytic emulsion viscosity reduction system, which uses surfactants to adjust the HLB value of the emulsion viscosity reduction system after mixing high-entropy oxides and oxidants to 7-14, wherein the oxidant is an organic peroxide.

[0006] Further preferably, the high-entropy oxide is an oxide of five or more than five kinds of transition metals selected from Fe, Mn, Co, Cr, Ni, Mo, Cu, Yb, La, Gd, Y, Ti, Ca, Mg and Nd.

[0007] Further preferably, the high-entropy oxide is composed of five transition metals, and the chemical general formula is (M1 0.25 M2 0.25 M3 0.25 M4 0.25 M5 0.25 )3O4, wherein M1, M2, M3, M4 and M5 are each a transition metal element, and the five transition metals are designed according to the principle of equimolar ratio.

[0008] The high-entropy oxide of the present application contains five or more than five different transition metals, each of which contains different d-orbital electron structures, and the activity is superimposed due to the cocktail effect, so that the electrophilicity is strong and the C-S and C-N bonds of the polycyclic aromatic hydrocarbons in the thick oil can be efficiently attacked, achieving the purpose of reducing the viscosity of the thick oil.

[0009] In the present application, the high-entropy oxide and the oxidant are combined into an emulsion viscosity reduction system by surfactants. The high-entropy oxide is dispersed at the oil-water interface of the emulsion, and the oxidant is in the oil phase of the emulsion. There is a large amount of water in the emulsion, and the purpose is to use the cooling characteristics of water, that is, water has a high specific heat capacity (4.2kJ·kg -1 ·K -1) and the characteristics of little change with temperature. One is to prevent the release of active oxygen by thermal decomposition of the oxidant, and the second is to reduce the frictional resistance of the system in the wellbore, avoiding the residual oxidant in the wellbore wall. Until entering the reservoir in the temperature constant 140℃ environment, emulsion demulsification occurs, high-entropy oxides contact with oxidants, through the formation of peroxide complex transition state material, carrying active oxygen attacks heavy oil and heavy ring aromatic side chain and heteroatom-containing carbon side chain, oxidation reaction occurs, and active oxygen material is used to cap alcohol, ketone and carboxylic acid, realizing the oxidation of heavy oil, and then using the surfactant contained in the system for emulsification, so that the sequence of catalysis and emulsification occurs.

[0010] The viscosity reduction principle of the present application is as follows:

[0011] The viscosity reduction of the present application is the combined use of catalytic oxidation viscosity reduction and emulsification viscosity reduction. Catalytic oxidation viscosity reduction uses high-entropy catalyst to convert heavy oil into oxidized oil with oxygen-containing groups and oxidized products with heteroatoms. Emulsification viscosity reduction uses catalytic oxidation products and surfactants contained in the catalytic emulsion to make oxidized oil into oil-in-water oxidized oil emulsion.

[0012] Catalytic oxidation technology: The oxidant in the catalytic viscosity reduction system is formed into a peroxide complex by the transition metal center in the catalyst, which attacks the heteroatom side chain of the heavy ring aromatic hydrocarbon in heavy oil, breaks the C-S bond, encapsulates with oxygen-containing groups (-OH), and performs deep oxidation, so that the oxygen-containing groups are mainly carboxyl groups (-COOH), and heavy oil oxidized oil and oxidized products containing heteroatoms such as sulfonic acid groups and dimethyl sulfoxide are obtained.

[0013] Emulsification technology: The organic molecules produced by the catalytic oxidation technology have dispersing properties and contain alcohol groups, carbonyl groups, carboxyl groups, and sulfonic acid groups. By means of these dispersing organic molecules, the surfactants contained in the catalytic system are used again to emulsify the oxidized heavy oil, so that the heavy oil is modified and the viscosity is reduced.

[0014] Further, the organic peroxide is any one of hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxy ester, peroxy carbonate, and ketone peroxide.

[0015] Further, the organic peroxide is any one of hydroperoxide, dialkyl peroxide, diacyl peroxide, peroxy ester, peroxy carbonate, and ketone peroxide.

[0016] Further, in the high-entropy catalytic emulsion viscosity reduction system, the mass ratio of the catalyst to the oxidant is 1:1 to 1:5.

[0017] Further, the surfactant is a composite surfactant composed of a hydrophilic surfactant and an oleophilic surfactant.

[0018] Further, the hydrophilic surfactant and the oleophilic surfactant are both non-ionic surfactants; wherein the hydrophilic non-ionic surfactant includes polyoxyethylene type, polyhydric alcohol type, alkanolamide type, polyether type, amine oxide type surfactants, and specifically can be Span-(sorbitan monolaurate); the oleophilic non-ionic surfactant includes Tween-(polysorbate).

[0019] In another aspect, the application provides a method for reducing the viscosity of thick oil by using the above high-entropy catalytic emulsion viscosity reduction system, comprising the following steps:

[0020] Mixing the high-entropy oxide and the oxidizing agent, and then adding the surfactant to obtain the emulsion viscosity reduction system;

[0021] Mixing the emulsion viscosity reduction system with the thick oil, heating to the catalytic reaction temperature for reaction, and completing the viscosity reduction of the thick oil after the reaction.

[0022] Further, the amount of the emulsion viscosity reduction system added is 0.02%-2% of the mass of the thick oil, calculated based on the high-entropy oxide.

[0023] Further, the catalytic reaction temperature is selected according to the type of transition metal, and is generally 50-180℃, and the reaction time is 1-48 hours.

[0024] Compared with the prior art, the application has the following effects:

[0025] In the low-temperature catalytic viscosity reduction method of thick oil in different prior arts, the air injection method is combined with lye and surfactants, the oxidation product carboxylic acid is treated by alkali to form petroleum carboxylate, and the carboxylate is used as an active agent for thick oil viscosity reduction and exploitation. In the application, the oxidizing agent is used as an oxygen source in the reservoir environment (50-180℃), the transition metal catalytic active phase is used to break the chemical bonds of the heteroatom side chains of thick oil, the oxidation thick oil is formed by end-capping with the oxidizing agent, and then the surfactant in the system is used for emulsification, so that the purpose of thick oil modification and viscosity reduction is achieved.

[0026] Unlike the traditional catalysts which use a single metal as an active center, the high-entropy oxide contains multiple transition metal components, which can realize performance control according to the element characteristics of different thick oil reservoirs, such as: a. Replacing some elements. In order to obtain the required performance, some elements in the high-entropy oxide can be replaced to prepare a new high-entropy oxide material, that is, to perform targeted performance control and optimization. b. Adjusting the proportion of transition metal elements in the high-entropy oxide. The content of electrophilic transition metal can be increased, which has a stronger attacking effect on the C-S and C-N bonds in the heavy components of thick oil, so as to achieve the purpose of bond breaking and improve the catalytic effect. DETAILED DESCRIPTION

[0027] The embodiments of the present application will be further described in conjunction with the following examples. The following examples are used to illustrate the present application but cannot be used to limit the scope of the present application.

[0028] Example 1

[0029] Emulsion viscosity reduction system configuration:

[0030] Prepare or purchase high-entropy oxide (Fe 0.25 Cr 0.25 Co 0.25 Ni 0.25 Cu 0.25 )3O4 (can be prepared using the technology disclosed in Wang S, Kaizhi G U, Wang D, et al. Angewandte Chemie International Edition, 2021, 133, 20415.)

[0031] Mix 1.0 g of high-entropy oxide and 2.0 g of benzoyl peroxide, and disperse them in 100 ml of deionized water. Add Tween 20 and Span 20 to configure an emulsion, and adjust the amount of Tween 20 and Span 20 to make the HLB value of the emulsion 9, to obtain an oil-in-water emulsion viscosity reduction system.

[0032] Thick oil viscosity reduction test:

[0033] According to the mass ratio of high-entropy oxide and thick oil, the amount of high-entropy oxide is 1%, the emulsion viscosity reduction system is put into the thick oil to form a catalytic oxidation system, and the reaction is carried out at 140℃ for 24h. The group components and viscosity are compared in the following Table 1 and Table 2.

[0034] Example 2

[0035] Emulsion viscosity reduction system configuration:

[0036] Prepare or purchase high-entropy oxide (Fe 0.25 Cr 0.25 Co 0.25 Ni 0.25 Cu 0.25 )3O4 (can be prepared using the technology disclosed in Wang S, Kaizhi G U, Wang D, et al. Angewandte Chemie International Edition, 2021, 133, 20415.)

[0037] 1.0 g high-entropy oxide and 2.0 g benzoyl peroxide were mixed and dispersed in 100 ml of deionized water, Tween 20 and Span 20 were added to configure an emulsion, and by adjusting the amount of Tween 20 and Span 20, the HLB value of the emulsion was 11, to obtain an oil-in-water emulsion viscosity reduction system;

[0038] Thick oil viscosity reduction test:

[0039] The amount of high-entropy oxide was 1% by mass ratio of high-entropy oxide and thick oil, the emulsion viscosity reduction system was put into the thick oil to form a catalytic oxidation system, and reacted at 140℃ for 24h, the group component and viscosity were compared as shown in Table 1 and Table 2.

[0040] Example 3

[0041] Emulsion viscosity reduction system configuration:

[0042] High-entropy oxide (Fe 0.25 Cr 0.25 Co 0.25 Ni 0.25 Cu 0.25 )3O4 was prepared or purchased (the technology disclosed in 86 Wang S, Kaizhi G U, Wang D, et al. Angewandte Chemie International Edition, 2021, 133, 20415 can be used)

[0043] 1.0 g high-entropy oxide and 2.0 g of cumene hydroperoxide were mixed and dispersed in 100 ml of deionized water, Tween 20 and Span 20 were added to configure an emulsion, and by adjusting the amount of Tween 20 and Span 20, the HLB value of the emulsion was 9, to obtain an oil-in-water emulsion viscosity reduction system;

[0044] Thick oil viscosity reduction test:

[0045] The amount of high-entropy oxide was 1% by mass ratio of high-entropy oxide and thick oil, the emulsion viscosity reduction system was put into the thick oil to form a catalytic oxidation system, and reacted at 140℃ for 24h, the group component and viscosity were compared as shown in Table 1 and Table 2.

[0046] Comparative Example 1

[0047] Emulsion viscosity reduction system configuration:

[0048] 1.0 g of iron oleate catalyst and 2.0 g of benzoyl peroxide were mixed and dispersed in 100 ml of deionized water, Tween 20 and Span 20 were added to configure an emulsion, and by adjusting the amount of Tween 20 and Span 20, the HLB value of the emulsion was 9, to obtain an emulsion viscosity reduction system;

[0049] Thick oil viscosity reduction test:

[0050] The amount of iron oleate was 1% calculated by the mass ratio of iron oleate and thick oil. The emulsion viscosity reduction system was put into the thick oil to form a catalytic oxidation system, and reacted at 140℃ for 24h. The group components and viscosity were compared as shown in Table 1 and Table 2.

[0051] Comparative Example 2

[0052] Viscosity reduction system configuration:

[0053] Preparation of high-entropy oxide (Fe 0.25 Cr 0.25 Co 0.25 Ni 0.25 Cu 0.25 )3O4 (prepared by the technology disclosed in Wang S, Gu, Wang D, et al. Angewandte Chemie International Edition, 2021, 133, 20415.)

[0054] 1.0g high-entropy oxide was dispersed in 100ml deionized water, Tween 20 and Span 20 were added to configure an emulsion, and by adjusting the amount of Tween 20 and Span 20, the HLB value of the emulsion was 9, to obtain an oil-in-water viscosity reduction system;

[0055] Thick oil viscosity reduction test:

[0056] The amount of high-entropy oxide was 1% calculated by the mass ratio of high-entropy oxide and thick oil. The viscosity reduction system was put into the thick oil to form a catalytic oxidation system, and reacted at 140℃ for 24h. The group components and viscosity were compared as shown in Table 1 and Table 2.

[0057] Table 1 Group components after reaction of different catalysts

[0058]

[0059] Table 2 Viscosity comparison after reaction of different catalysts (measured at 40℃)

[0060]

[0061] By comparing the group components and viscosity, the high-entropy oxide as a catalyst, the asphaltene of the modified oil of Example 1 was reduced by 8%, and the light component was increased significantly. The viscosity reduction rate of the high-entropy system reached 98%, and compared with the iron oleate catalyst containing a single transition metal, the modification and viscosity reduction effect was obviously increased.

[0062] The above embodiments are only used for illustrating the present application, but not limiting the present application. Although the present application is explained in detail with reference to the embodiments, those skilled in the art should understand that various combinations, modifications or equivalent replacements of the technical solutions of the present application do not deviate from the spirit and scope of the present application, and should be covered in the scope of claims of the present application.

Claims

1. A high-entropy catalytic emulsion viscosity-reducing composition, characterized in that: An emulsion viscosity-reducing composition with an HLB value adjusted to 7-14 by mixing high-entropy oxides and oxidants using surfactants, wherein the oxidant is an organic peroxide; The high-entropy oxide is an oxide composed of five or more elements selected from the transition metals Fe, Mn, Co, Cr, Ni, Mo, Cu, Yb, La, Gd, Y, Ti, Ca, Mg, and Nd. The surfactant is a composite surfactant composed of a hydrophilic surfactant and a lipophilic surfactant; The organic peroxide is benzoyl peroxide; In the high-entropy catalytic emulsion viscosity-reducing composition, the mass ratio of high-entropy oxide to oxidant is 1:1 to 1:

5.

2. The high-entropy catalytic emulsion viscosity-reducing composition according to claim 1, characterized in that: Both the hydrophilic surfactant and the lipophilic surfactant are nonionic surfactants.

3. The high-entropy catalytic emulsion viscosity-reducing composition according to claim 2, characterized in that: The hydrophilic surfactant includes any one or more of the following: polyoxyethylene type, polyol type, alkanolamide type, polyether type, and amine oxide type surfactants; the lipophilic surfactant is polysorbate.

4. A method for reducing the viscosity of heavy oil using the high-entropy catalytic emulsion viscosity-reducing composition according to any one of claims 1-3, characterized in that, Includes the following steps: A high-entropy oxide and an oxidant are mixed and then a surfactant is added to obtain an emulsion viscosity-reducing composition; The emulsion viscosity-reducing composition is mixed with heavy oil and heated to 50-180°C for reaction. After the reaction is completed, the heavy oil is modified and its viscosity is reduced.

5. The method for reducing the viscosity of heavy oil according to claim 4, characterized in that: Based on high-entropy oxides, the amount of emulsion viscosity-reducing composition added is 0.02%-2% of the mass of heavy oil.

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