Benzylic alcohol modified humic acid, and preparation method and application thereof

Abstract

The application provides benzyl alcohol modified humic acid and a preparation method and application thereof, and belongs to the oil displacement technical field. The preparation method comprises the following steps: mixing humic acid and deionized water to obtain a mixture I, adding acid KMnO4 to the mixture I after heating and temperature rising to an oxidation reaction temperature, and performing an oxidation reaction after heat preservation; after the oxidation reaction is completed, washing, centrifugation and freeze-drying are performed to obtain oxidized humic acid; the oxidized humic acid is mixed with a solvent to obtain a mixed solution; the benzyl alcohol, phosphorus trichloride and the solvent are mixed, a catalyst is added, the mixed solution is added, and temperature rising is performed to perform a reaction; after the reaction is completed, rotary evaporation, washing, standing, filtration and drying are performed to obtain benzyl alcohol modified humic acid. Humic acid is selected as a raw material to perform a first step of oxidation reaction, and a second step of modification of the oxidized humic acid by using benzyl alcohol is performed to prepare a kind of benzyl alcohol modified humic acid with a condensed polycyclic aromatic ring structure, which is an oil-soluble surfactant at normal temperature and is changed into a water-soluble surfactant according to the change of the formation environment.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil displacement in oil fields, and particularly relates to benzyl alcohol modified humic acid and a preparation method and application thereof. BACKGROUND

[0002] Nowadays, oil is still the most demanded one among many energy forms. A large amount of light conventional crude oil is exploited, and the exploitation of heavy oil is more difficult. Physical measures alone cannot effectively solve the problem, and thus tertiary oil recovery technology is proposed. It is found in tertiary oil recovery that the recovery rate of chemical agent displacement is higher than that of other displacement modes, and the surfactant displacement in chemical displacement is the most promising in development and application. The surfactants for oil displacement mainly include nonionic surfactants such as fatty alcohol polyoxyether, anionic surfactants such as petroleum sulfonates, cationic surfactants such as betaine type, and amphoteric surfactants. The surfactant can effectively reduce the interfacial tension between the displacement phase and the crude oil due to its special molecular structure of hydrophilic and lipophilic groups, has good emulsifying capacity, and at the same time, the surfactant adheres to the rock surface, causing the rock to be wet reversed.

[0003] In the later stage of tertiary oil recovery, heavy oil, residual oil is mainly collected by thermal oil recovery technology, which has problems of low oil displacement efficiency, damage to oil layer stability, sand production or well wall collapse, and the like. In addition, heavy oil has the characteristics of high viscosity, high solidification point and rich in gum and asphaltene, which is difficult to exploit due to adhesion to the rock surface and pore throat. It is urgent to explore an ideal oil displacement agent which can effectively reduce the viscosity of heavy oil without damaging the formation environment, thereby improving the oil recovery rate. SUMMARY

[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a benzyl alcohol modified humic acid and a preparation method and application thereof, so as to solve the technical problems that heavy oil adheres to the rock and is difficult to exploit, the oil displacement efficiency is low, the oil layer stability is damaged, and sand production or well wall collapse is caused when collecting heavy oil in the prior art. The modified humic acid prepared by the preparation method can effectively reduce the viscosity of heavy oil without damaging the formation environment, thereby improving the oil recovery rate.

[0005] In order to achieve the above-mentioned purpose, the following technical solutions are adopted in the present application:

[0006] The present application provides a preparation method of benzyl alcohol modified humic acid, comprising the following steps:

[0007] S1: mixing humic acid and deionized water to obtain a mixture I, heating the mixture I to an oxidation reaction temperature, adding acidic KMnO4, and performing an oxidation reaction under insulation, washing, centrifuging and freeze-drying after the oxidation reaction is completed, to obtain oxidized humic acid;

[0008] S2: mixing the oxidized humic acid with a solvent to obtain a mixed solution; mixing benzyl alcohol, phosphorus trichloride and the solvent, adding a catalyst, adding the mixed solution, and then heating to perform a reaction; after the reaction, performing rotary evaporation, washing, standing, filtering and drying to obtain benzyl alcohol modified humic acid.

[0009] Further, in the S1, the mass ratio of the humic acid to deionized water is 1:(1-6); and the mass ratio of the humic acid to acidic KMnO4 is (2-3):1.

[0010] Further, in the S1, the oxidation reaction temperature is 60-80℃; and the oxidation reaction time is 2-3h.

[0011] Further, in the S2, the mass ratio of the oxidized humic acid to the solvent is 1:(1-2).

[0012] Further, in the S2, the mass ratio of the benzyl alcohol, phosphorus trichloride and the solvent is 1:(0.2-0.5):15.

[0013] Further, in the S2, the solvent is dichloromethane or acetone, and the catalyst is concentrated sulfuric acid.

[0014] Further, in the S2, the temperature of adding the mixed solution is 50-60℃; and the time of adding the mixed solution is 15-30min.

[0015] Further, in the S2, the reaction temperature is 120-130℃, and the reaction time is 3-4h.

[0016] The application further provides the benzyl alcohol modified humic acid prepared by the preparation method of the benzyl alcohol modified humic acid.

[0017] The application further provides the application of the benzyl alcohol modified humic acid prepared by the preparation method of the benzyl alcohol modified humic acid as an oil displacement agent in an oil field.

[0018] Compared with the prior art, the application has the following beneficial effects:

[0019] The application provides a preparation method of benzyl alcohol modified humic acid, which selects humic acid as a raw material to perform an oxidation reaction, and then modifies the oxidized humic acid by using benzyl alcohol. The oxidation treatment of the humic acid as a raw material aims to increase the content of carboxyl groups around the humic acid molecules. Phosphorus trichloride can simultaneously perform a phosphoric acid esterification reaction on the hydroxyl groups. The benzyl alcohol modifies the oxidized humic acid, blocks the hydrophilic groups on the surface of the humic acid, and has good lipophilicity. Meanwhile, the benzyl alcohol has a condensed polycyclic aromatic ring structure, can form stable π-π interactions with petroleum asphaltene molecules, and is more easily attached to and infiltrated into heavy oil.

[0020] The modified humic acid prepared according to the preparation method has a fused polycyclic aromatic ring structure, is an oil-soluble surfactant at room temperature, and is changed into a water-soluble surfactant according to the change of the formation environment. The benzyl alcohol modified humic acid is beneficial to the hydrolysis of ester groups in a high-temperature alkaline environment after being injected into the formation, the hydrophilicity is enhanced, the positioning ability of the surfactant is improved, the heavy oil is transferred to the water phase, and therefore the heavy oil recovery rate is improved.

[0021] The modified humic acid prepared according to the preparation method has a fused polycyclic aromatic ring structure, is an oil-soluble surfactant at room temperature, and is changed into a water-soluble surfactant according to the change of the formation environment. The benzyl alcohol modified humic acid is beneficial to the hydrolysis of ester groups in a high-temperature alkaline environment after being injected into the formation, the hydrophilicity is enhanced, the positioning ability of the surfactant is improved, the heavy oil is transferred to the water phase, and therefore the heavy oil recovery rate is improved.

[0022] The modified humic acid prepared according to the preparation method has a fused polycyclic aromatic ring structure, is an oil-soluble surfactant at room temperature, and is changed into a water-soluble surfactant according to the change of the formation environment. The benzyl alcohol modified humic acid is beneficial to the hydrolysis of ester groups in a high-temperature alkaline environment after being injected into the formation, the hydrophilicity is enhanced, the positioning ability of the surfactant is improved, the heavy oil is transferred to the water phase, and therefore the heavy oil recovery rate is improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The preparation reaction mechanism diagram of the present application is shown in the figure.

[0024] Figure 2 The general formula of the humic acid structure of the present application is shown in the figure. DETAILED DESCRIPTION

[0025] In order for those skilled in the art to understand the characteristics and effects of the present application, the following is a general description and definition of the terms and phrases mentioned in the specification and claims. Unless otherwise specified, all technical and scientific words used herein have their usual meanings to those skilled in the art of the present application, and in case of conflict, the definition in the specification shall prevail.

[0026] Theories or mechanisms described and disclosed herein, whether correct or not, should not be construed as limiting the scope of the present application, i.e., the present application can be practiced without being limited by any particular theory or mechanism.

[0027] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents and concentrations, are for the sake of brevity and convenience. Therefore, the description of numerical ranges or percentage ranges should be considered to have encompassed and specifically disclosed all possible sub-ranges and individual numerical values within the range (including integers and fractions).

[0028] In this document, the terms "comprise", "include", "contain", "have" and the like are used in their inclusive sense, that is, to mean "including but not limited to". Additionally, the words "plurality" and "a plurality" mean "two or more".

[0029] In this document, all possible combinations between various technical features of the various embodiments or examples are not described in order to simplify the present description. Therefore, any combination of the technical features of the various embodiments or examples is possible, provided that such a combination does not result in an obvious contradiction.

[0030] The present application provides a benzyl alcohol modified humic acid and a preparation method and application thereof.

[0031] The present application will be further described in conjunction with specific examples. It should be understood that these examples are used to illustrate the present application but not to limit the scope of the present application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the present application after reading the content taught by the present application, and these equivalent forms also fall within the scope defined by the appended claims of the present application.

[0032] In the following examples, the instruments and apparatuses of the art are used. In the following examples, the experimental methods not specified with specific conditions are usually carried out according to the conventional conditions or according to the conditions suggested by the manufacturers. In the following examples, various raw materials are used, unless otherwise specified, the conventional commercially available products are used, and the specifications are the conventional specifications in the art. In the specification of the present application and the following examples, unless otherwise specified, "%" means weight percent, "parts" means weight parts, and the ratio means weight ratio.

[0033] The present application provides a preparation method of benzyl alcohol modified humic acid, and the specific steps are as follows:

[0034] The humic acid and deionized water are mixed uniformly at a mass ratio of 1:(1-6), and then slowly added with acid KMnO4 at a mass ratio of 1:(2-3) to the humic acid at an oxidation reaction temperature of 60-80°C, and the oxidation reaction is carried out for 2-3h under insulation and stirring. After sufficient reaction, washing, centrifugation and freeze-drying are carried out to obtain oxidized humic acid. The humic acid is selected as the raw material to carry out the first step of oxidation reaction.

[0035] The benzyl alcohol modified humic acid is prepared by the following method: mixing and dissolving benzyl alcohol, phosphorus trichloride and a solvent (dichloromethane or acetone) in a mass ratio of 1:(0.2-0.5):15, adding a catalyst concentrated sulfuric acid, slowly adding an oxidized humic acid and a solvent (dichloromethane or acetone) mixed solution in a mass ratio of 1:(1-2) at 50-60 DEG C, and completing the dropping within 15-30 min, then increasing the temperature to 120-130 DEG C, and reacting for 3-4 h until completion, removing the solvent by rotary evaporation, washing with hot water for 3-4 times, filtering, and vacuum drying to obtain the benzyl alcohol modified humic acid.

[0036] The reaction mechanism is shown as follows,

[0037]

[0038] wherein R is a humic acid structure general formula:

[0039]

[0040] The benzyl alcohol modified humic acid prepared by the method has the advantages that: the natural component humic acid is used as a reaction raw material, the cost is low, the degradation is easy, and the environment is friendly; from the perspective of molecular structure design, the surfactant has a condensed multi-aromatic ring structure, a pi-pi interaction with asphaltene multi-aromatic nucleus, and a more easy to soak and adhere contact with crude oil; the benzyl alcohol modified humic acid blocks the hydrophilic groups on the surface of the humic acid, and has good lipophilicity; the surfactant molecule is easily adsorbed and arranged on the air / water surface, the macromolecule is more easily formed into micelles, so that the surface tension of water is reduced, the water solubility is enhanced, and the surfactant has good emulsifying property and stability.

[0041] The benzyl alcohol modified humic acid prepared by the method has the advantages that: the natural component humic acid is used as a reaction raw material, the cost is low, the degradation is easy, and the environment is friendly; from the perspective of molecular structure design, the surfactant has a condensed multi-aromatic ring structure, a pi-pi interaction with asphaltene multi-aromatic nucleus, and a more easy to soak and adhere contact with crude oil; the benzyl alcohol modified humic acid blocks the hydrophilic groups on the surface of the humic acid, and has good lipophilicity; the surfactant molecule is easily adsorbed and arranged on the air / water surface, the macromolecule is more easily formed into micelles, so that the surface tension of water is reduced, the water solubility is enhanced, and the surfactant has good emulsifying property and stability.

[0042] Example 1

[0043] 1) 6g humic acid is placed in a three-necked flask, 6mL distilled water is added, and after stirring and uniform, 2g acid KMnO4 is slowly added under heating to 60 DEG C, and the reaction is carried out for 2h under heating and stirring, after sufficient reaction, washing, centrifugation and freeze drying, the oxidized humic acid is obtained;

[0044] 2) In a three-necked flask, 18 g of benzyl alcohol, 5.4 g of phosphorus trichloride and 30 mL of dichloromethane were added, after being fully dissolved, concentrated sulfuric acid was added, 8 g of oxidized humic acid and oxidized humic acid with a mass ratio of 1:1.5 in dichloromethane were slowly added dropwise at 50°C, and the dropwise addition was completed within 20 min, then the temperature was raised to 120°C, and the reaction was carried out for 3 h until completion, the solvent was removed by rotary evaporation, and the product was washed with hot water and left to stand for 4 times, then filtered and vacuum dried to obtain benzyl alcohol modified humic acid.

[0045] Example 2

[0046] 1) 6 g of humic acid was placed in a three-necked flask, 18 mL of distilled water was added, and after being uniformly stirred, 3 g of acidic KMnO4 was slowly added dropwise at 70°C, and the reaction was carried out for 3 h under stirring and temperature maintenance, after sufficient reaction, washing, centrifugation and freeze-drying, oxidized humic acid was obtained;

[0047] 2) In a three-necked flask, 18 g of benzyl alcohol, 5.4 g of phosphorus trichloride and 30 mL of dichloromethane were added, after being fully dissolved, concentrated sulfuric acid was added, 8 g of oxidized humic acid and oxidized humic acid with a mass ratio of 1:1.5 in dichloromethane were slowly added dropwise at 50°C, and the dropwise addition was completed within 20 min, then the temperature was raised to 120°C, and the reaction was carried out for 3 h until completion, the solvent was removed by rotary evaporation, and the product was washed with hot water and left to stand for 4 times, then filtered and vacuum dried to obtain benzyl alcohol modified humic acid.

[0048] Example 3

[0049] 1) 6 g of humic acid was placed in a three-necked flask, 30 mL of distilled water was added, and after being uniformly stirred, 3 g of acidic KMnO4 was slowly added dropwise at 80°C, and the reaction was carried out for 3 h under stirring and temperature maintenance, after sufficient reaction, washing, centrifugation and freeze-drying, oxidized humic acid was obtained;

[0050] 2) In a three-necked flask, 18 g of benzyl alcohol, 9 g of phosphorus trichloride and 30 mL of dichloromethane were added, after being fully dissolved, concentrated sulfuric acid was added, 12 g of oxidized humic acid and oxidized humic acid with a mass ratio of 1:2 in dichloromethane were slowly added dropwise at 50°C, and the dropwise addition was completed within 30 min, then the temperature was raised to 130°C, and the reaction was carried out for 4 h until completion, the solvent was removed by rotary evaporation, and the product was washed with hot water and left to stand for 4 times, then filtered and vacuum dried to obtain benzyl alcohol modified humic acid.

[0051] Example 4

[0052] 1) 6 g of humic acid was placed in a three-necked flask, 6 mL of distilled water was added, and after being uniformly stirred, 2 g of acidic KMnO4 was slowly added dropwise at 60°C, and the reaction was carried out for 2 h under stirring and temperature maintenance, after sufficient reaction, washing, centrifugation and freeze-drying, oxidized humic acid was obtained;

[0053] 2) In a three-necked flask, 18 g of benzyl alcohol, 5.4 g of phosphorus trichloride and 30 mL of acetone were added, after being fully dissolved, concentrated sulfuric acid was added, 8 g of the mixed solution of oxidized humic acid and oxidized humic acid with a mass ratio of 1:1.5 in acetone was slowly added dropwise at 50°C, the addition was completed within 20 min, then the temperature was raised to 120°C, and the reaction was carried out for 3 h until completion, the solvent was removed by rotary evaporation, and the product was washed with hot water and left to stand for 4 times, then filtered and vacuum dried to obtain benzyl alcohol modified humic acid.

[0054] Example 5

[0055] 1) 6 g of humic acid was placed in a three-necked flask, 18 mL of distilled water was added, after being uniformly stirred, 3 g of acidic KMnO4 was slowly added dropwise at 70°C, and the reaction was carried out for 3 h under the condition of constant temperature and stirring, after the reaction was completed, the product was washed, centrifuged and freeze-dried to obtain oxidized humic acid;

[0056] 2) In a three-necked flask, 18 g of benzyl alcohol, 5.4 g of phosphorus trichloride and 30 mL of acetone were added, after being fully dissolved, concentrated sulfuric acid was added, 8 g of the mixed solution of oxidized humic acid and oxidized humic acid with a mass ratio of 1:1.5 in acetone was slowly added dropwise at 50°C, the addition was completed within 20 min, then the temperature was raised to 120°C, and the reaction was carried out for 3 h until completion, the solvent was removed by rotary evaporation, and the product was washed with hot water and left to stand for 4 times, then filtered and vacuum dried to obtain benzyl alcohol modified humic acid.

[0057] Example 6

[0058] 1) 6 g of humic acid was placed in a three-necked flask, 30 mL of distilled water was added, after being uniformly stirred, 3 g of acidic KMnO4 was slowly added dropwise at 80°C, and the reaction was carried out for 3 h under the condition of constant temperature and stirring, after the reaction was completed, the product was washed, centrifuged and freeze-dried to obtain oxidized humic acid;

[0059] 2) In a three-necked flask, 18 g of benzyl alcohol, 9 g of phosphorus trichloride and 30 mL of acetone were added, after being fully dissolved, concentrated sulfuric acid was added, 12 g of the mixed solution of oxidized humic acid and oxidized humic acid with a mass ratio of 1:2 in acetone was slowly added dropwise at 50°C, the addition was completed within 30 min, then the temperature was raised to 130°C, and the reaction was carried out for 4 h until completion, the solvent was removed by rotary evaporation, and the product was washed with hot water and left to stand for 4 times, then filtered and vacuum dried to obtain benzyl alcohol modified humic acid.

[0060] Example 7

[0061] 1) 6 g of humic acid was placed in a three-necked flask, 30 mL of distilled water was added, after being uniformly stirred, 3 g of acidic KMnO4 was slowly added dropwise at 80°C, and the reaction was carried out for 3 h under the condition of constant temperature and stirring, after the reaction was completed, the product was washed, centrifuged and freeze-dried to obtain oxidized humic acid;

[0062] 2) In a three-necked flask, 18 g of benzyl alcohol, 9 g of phosphorus trichloride and 30 mL of acetone were added, after being dissolved thoroughly, concentrated sulfuric acid was added, 12 g of oxidized humic acid was added in the mixed solution of acetone with the mass ratio of oxidized humic acid to oxidized humic acid being 1:2, the temperature was slowly dropped at 50°C, the dropping was completed within 30 min, then the temperature was increased to 130°C, and the reaction was carried out for 4 h until it was completed, the solvent was removed by rotary evaporation, hot water was washed for 4 times, then it was filtered, and vacuum dried, thus benzyl alcohol modified humic acid was obtained.

[0063] Comparative test

[0064] The surface, interfacial tension and thickened oil displacement experiment in simulated formation environment of the products prepared in examples 1-6 were carried out respectively, and the oil displacement efficiency was shown in table 1.

[0065] Table 1

[0066]

[0067]

[0068] The results showed that the surfactant exhibited better surface activity, and the oil displacement efficiency was greatly increased, which could be up to 88%.

[0069] The above content is only for illustrating the technical idea of the present application, and cannot limit the protection scope of the present application, any modification made according to the technical idea of the present application on the basis of technical scheme, falls into the protection scope of the present application.

Claims

1. A method for preparing benzyl alcohol-modified humic acid, characterized by, It comprises the following steps: S1: mixing humic acid with deionized water to obtain mixture I, heating mixture I to an oxidation reaction temperature, adding acidic KMnO4, and keeping warm to perform oxidation reaction, washing, centrifuging, freeze-drying after the oxidation reaction is completed, and obtaining oxidized humic acid; S2: mixing oxidized humic acid with a solvent to obtain a mixed solution; mixing benzyl alcohol, phosphorus trichloride and the solvent, adding a catalyst, adding the mixed solution, and heating to perform reaction, performing rotary evaporation, washing, standing, filtering and drying after the reaction is completed, and obtaining benzyl alcohol modified humic acid; In S2, the solvent is dichloromethane or acetone, and the catalyst is concentrated sulfuric acid. In S2, the temperature of the reaction is 120-130℃, and the reaction time is 3-4h.

2. The method for preparing benzyl alcohol-modified humic acid according to claim 1, characterized in that, In S1, the mass ratio of humic acid to deionized water is 1:(1-6), and the mass ratio of humic acid to acidic KMnO4 is (2-3):

1.

3. The method for preparing benzyl alcohol-modified humic acid according to claim 1, characterized in that, In S1, the oxidation reaction temperature is 60-80℃, and the reaction time of the oxidation reaction is 2-3h.

4. The method for preparing benzyl alcohol-modified humic acid according to claim 1, characterized in that, In S2, the mass ratio of oxidized humic acid to solvent is 1:(1-2).

5. The method for preparing benzyl alcohol-modified humic acid according to claim 1, characterized in that, In S2, the mass ratio of benzyl alcohol, phosphorus trichloride and solvent is 1:(0.2-0.5):

15.

6. The method for preparing benzyl alcohol-modified humic acid according to claim 1, characterized in that, In S2, the mixed solution is added dropwise at a temperature of 50-60℃, and the dropwise addition is completed within 15-30min. 7.A benzyl alcohol modified humic acid prepared by the preparation method of the benzyl alcohol modified humic acid according to any one of claims 1 to 6. 8.Use of the benzyl alcohol modified humic acid prepared by the preparation method of the benzyl alcohol modified humic acid according to any one of claims 1 to 6 as an oil displacement agent in an oil field.

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