Auxiliary emulsifier for oil-based drilling fluid and preparation method thereof

Abstract

The present invention relates to the technical field of auxiliary emulsifier preparation, specifically an auxiliary emulsifier for oil-based drilling fluid and a preparation method thereof. The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method: adding sulfonated ricinoleic acid to a white oil solution of maleic anhydride grafted polybutadiene, then adding a mixed amine to carry out an amidation reaction to obtain a product, then adding epibromohydrin to the product to carry out a reaction, and then adding the remaining amount of white oil and stirring and homogenizing to obtain the product. The auxiliary emulsifier for oil-based drilling fluid is prepared using sulfonated ricinoleic acid, the white oil solution of maleic anhydride grafted polybutadiene, the mixed amine, and epibromohydrin as main raw materials, and has stable high-temperature performance and excellent salt resistance.

Description

Technical Field

[0001] The invention relates to the technical field of auxiliary emulsifier preparation, in particular to an auxiliary emulsifier for oil-based drilling fluid and a preparation method thereof. Background Art

[0002] Oil-based drilling fluid is a commonly used drilling fluid system in the field of oil and gas drilling, and plays an irreplaceable role in deep, ultra-deep and complex geological conditions. Oil-based drilling fluid has the advantages of high temperature resistance, strong inhibition, good lubricity and little damage to oil and gas layers. Its base fluid is an oil-in-water emulsion. The stability of the emulsion determines the drilling fluid performance, and the auxiliary emulsifier is crucial to the stability of the emulsion. Among them, the effects of the auxiliary emulsifier mainly include: 1. Interface adsorption: the auxiliary emulsifier molecules are adsorbed on the oil-water interface, reducing interfacial tension and preventing water droplets from coalescing; 2. Interfacial film strengthening: a stable interfacial film is formed at the oil-water interface to improve the mechanical strength of the emulsion; 3. Steric hindrance: the auxiliary emulsifier with a macromolecular structure prevents the coalescence between water droplets through the steric hindrance effect.

[0003] Currently, the use of auxiliary emulsifiers in drilling fluids in China is developing rapidly, but there are still many problems. For example, after high-temperature boiling, the demulsification voltage of oil-based drilling fluid systems prepared with them is greatly reduced, the stability is reduced, the rheological properties fluctuate greatly, and the production cost is high.

[0004] In recent years, amide emulsifiers have been widely used in oil-based drilling fluids both domestically and internationally. The hydrophilic amide groups and lipophilic long carbon chains on their molecules can be oriented and adsorbed at the oil-water interface, reducing interfacial tension and forming a high-strength interfacial film. This results in excellent temperature resistance and emulsification properties. Polyamide emulsifiers are particularly commonly used.

[0005] For example, Chinese patent document CN105907381A discloses a polyamide auxiliary emulsifier for oil-based drilling fluid and a preparation method. The patent discloses a polyamide auxiliary emulsifier for oil-based drilling fluid, which is prepared by dehydration reaction and condensation of three monomers: a dibasic acid anhydride, a polyene polyamine, and a fatty acid. The fatty acid is a mixture of oleic acid and linoleic acid in any proportion. The polyene polyamine is one of ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine. The dibasic acid anhydride is one of malonic anhydride, maleic anhydride, succinic anhydride, glutaric anhydride, and adipic anhydride. The drilling fluid prepared with the polyamide auxiliary emulsifier has stable rheological properties, low high-temperature and high-pressure fluid loss, strong demulsification voltage, and good high-temperature resistance.

[0006] To improve high-temperature thermal stability, sulfonic acid emulsifiers have emerged. They introduce sulfonic acid groups into the molecule and utilize their strong hydration effect to enhance the interfacial film strength and improve high-temperature stability.

[0007] Alkyl primary amine emulsifiers are composed of a lipophilic group containing 8 to 12 carbon atoms and a hydrophilic amine group. Emulsifiers with different properties can be obtained by changing the structure, such as introducing hydrophilic or hydrophobic groups.

[0008] In summary, although the auxiliary emulsifiers used in domestic drilling fluids have developed rapidly, the above-mentioned oil-based drilling fluid auxiliary emulsifiers still have problems such as high cost, unstable high-temperature performance and poor salt resistance.

[0009] In view of this, there is an urgent need to develop an auxiliary emulsifier for oil-based drilling fluid with low production cost, stable high temperature performance and excellent salt resistance. Summary of the Invention

[0010] The present invention provides an auxiliary emulsifier for oil-based drilling fluid and a preparation method thereof, which overcomes the deficiencies of the above-mentioned prior art and can effectively solve the problems of high production cost, unstable high temperature performance and poor salt resistance of the existing auxiliary emulsifiers.

[0011] One of the technical solutions of the present invention is achieved by the following measures: an auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0012] In the first step, polybutadiene, maleic anhydride and a portion of white oil are mixed and stirred under a nitrogen atmosphere until dissolved to obtain a mixture;

[0013] In the second step, dicumyl peroxide is added to the mixture to cause graft polymerization reaction to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0014] The third step is to add sulfonated ricinoleic acid to the white oil solution of maleic anhydride grafted polybutadiene, and then add mixed amine to carry out amidation reaction to obtain a product, wherein the sulfonated ricinoleic acid is obtained by sulfonation reaction of ricinoleic acid and chlorosulfonic acid;

[0015] In the fourth step, epibromopropane is added to the product to react, and then the remaining amount of white oil is added and stirred to obtain an auxiliary emulsifier for oil-based drilling fluid.

[0016] The following is a further optimization and / or improvement of one of the above-mentioned technical solutions:

[0017] In the third step, sulfonated ricinoleic acid is obtained by the following method:

[0018] S1, placing ricinoleic acid and dichloromethane in a reactor, and lowering the temperature of the reactor to 0°C to 5°C;

[0019] S2, adding chlorosulfonic acid to the reactor, controlling the temperature to be 0°C to 10°C, and after the addition is complete, heating the reactor to 25°C to 30°C, stirring and reacting for 2h to 3h to obtain a mixed solution;

[0020] S3, distilling the mixed solution under reduced pressure, washing with anhydrous ethanol 3 to 4 times, and vacuum drying to obtain sulfonated ricinoleic acid.

[0021] In the above step S1, the mass ratio of ricinoleic acid to dichloromethane is 10:(35 to 45), and in step S2, the mass ratio of ricinoleic acid to chlorosulfonic acid is 10:(2 to 3).

[0022] In the first step, the mass ratio of polybutadiene, maleic anhydride and a portion of white oil is 8:(1 to 2):(26 to 28).

[0023] In the second step, the mass ratio of polybutadiene to dicumyl peroxide is 8:(0.02 to 0.04).

[0024] In the third step, the mass ratio of polybutadiene, sulfonated ricinoleic acid and mixed amine is 8:(5 to 7):(1.5 to 2.5).

[0025] In the third step, the mixed amine is a mixture of diethylenetriamine and triethylenetetramine in a mass ratio of (1.5 to 2.5):1.

[0026] In the fourth step, the mass ratio of polybutadiene, epibromohydrin and the remaining white oil is 8: (0.8 to 1.0): (10 to 12).

[0027] In the second step, during the graft polymerization reaction, the reaction temperature is 130° C. to 150° C., and the reaction time is 3 h to 4 h.

[0028] In the third step, during the amidation reaction, the reaction temperature is 90° C. to 110° C., and the reaction time is 2 h to 3 h.

[0029] In the fourth step, the reaction temperature is 50° C. to 60° C., and the reaction time is 2 h to 3 h.

[0030] The second technical solution of the present invention is achieved by the following measures: an auxiliary emulsifier for oil-based drilling fluid is prepared by the following method:

[0031] In the first step, polybutadiene, maleic anhydride and a portion of white oil are mixed and stirred under a nitrogen atmosphere until dissolved to obtain a mixture;

[0032] In the second step, dicumyl peroxide is added to the mixture to cause graft polymerization reaction to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0033] The third step is to add sulfonated ricinoleic acid to the white oil solution of maleic anhydride grafted polybutadiene, and then add mixed amine to carry out amidation reaction to obtain a product, wherein the sulfonated ricinoleic acid is obtained by sulfonation reaction of ricinoleic acid and chlorosulfonic acid;

[0034] In the fourth step, epibromopropane is added to the product to react, and then the remaining amount of white oil is added and stirred to obtain an auxiliary emulsifier for oil-based drilling fluid.

[0035] The auxiliary emulsifier for oil-based drilling fluid is prepared from sulfonated ricinoleic acid, a white oil solution of maleic anhydride grafted polybutadiene, mixed amines and epibromopropane as main raw materials, and has stable high-temperature performance and excellent salt resistance. DETAILED DESCRIPTION

[0036] The present invention is not limited to the following embodiments, and specific implementation methods can be determined based on the technical solutions of the present invention and actual conditions. Unless otherwise specified, the various chemical reagents and chemicals mentioned in the present invention are all chemical reagents and chemicals commonly known in the prior art; unless otherwise specified, the percentages in the present invention are all percentages by mass; unless otherwise specified, the solutions in the present invention are all aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous hydrochloric acid solution; normal temperature and room temperature in the present invention generally refer to temperatures between 15°C and 25°C, and are generally defined as 25°C.

[0037] Below in conjunction with embodiment, the present invention will be further described:

[0038] Example 1: The oil-based drilling fluid auxiliary emulsifier is obtained by the following method:

[0039] In the first step, polybutadiene, maleic anhydride and a portion of white oil are mixed and stirred under a nitrogen atmosphere until dissolved to obtain a mixture;

[0040] In the second step, dicumyl peroxide is added to the mixture to cause graft polymerization reaction to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0041] The third step is to add sulfonated ricinoleic acid to the white oil solution of maleic anhydride grafted polybutadiene, and then add mixed amine to carry out amidation reaction to obtain a product, wherein the sulfonated ricinoleic acid is obtained by sulfonation reaction of ricinoleic acid and chlorosulfonic acid;

[0042] In the fourth step, epibromopropane is added to the product to react, and then the remaining amount of white oil is added and stirred to obtain an auxiliary emulsifier for oil-based drilling fluid.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] First, the auxiliary emulsifier for oil-based drilling fluids of the present invention is compatible with various hydrocarbon oil phases (diesel, white oil, synthetic esters, etc.). The emulsion prepared using the auxiliary emulsifier for oil-based drilling fluids of the present invention has a uniform particle size distribution, and the product has a composite structure of sulfonic acid groups + amino groups + hydrophobic chains, which significantly improves the emulsification effect and can maintain long-term stability.

[0045] Second, the raw materials of the auxiliary emulsifier for oil-based drilling fluid of the present invention, such as ricinoleic acid and polybutadiene, are bulk industrial products, easy to purchase, and have low production costs;

[0046] Third, the auxiliary emulsifier for oil-based drilling fluid of the present invention has good salt resistance, with an emulsion water separation rate of less than 2% in a 20% NaCl solution, and can maintain stable performance within a pH range of 4 to 11;

[0047] Fourthly, in the present invention, the synthesis of the white oil solution of maleic anhydride grafted polybutadiene and the auxiliary emulsifier for oil-based drilling fluid is directly and continuously carried out in the same white oil system, eliminating the steps of separation and purification, and achieving high production efficiency.

[0048] Example 2: As an optimization of the above example, in the third step, sulfonated ricinoleic acid is obtained by the following method:

[0049] S1, placing ricinoleic acid and dichloromethane in a reactor, and lowering the temperature of the reactor to 0°C to 5°C;

[0050] S2, adding chlorosulfonic acid to the reactor, controlling the temperature to be between 0°C and 10°C, and after the addition is complete, heating the reactor to 25°C to 30°C, stirring and reacting for 2h to 3h to obtain a mixed solution;

[0051] S3, distilling the mixed solution under reduced pressure, washing with anhydrous ethanol 3 to 4 times, and vacuum drying to obtain sulfonated ricinoleic acid.

[0052] Example 3: As an optimization of the above example, in step S1, the mass ratio of ricinoleic acid to dichloromethane is 10:(35 to 45), and in step S2, the mass ratio of ricinoleic acid to chlorosulfonic acid is 10:(2 to 3).

[0053] Example 4: As an optimization of the above example, in the first step, the mass ratio of polybutadiene, maleic anhydride and a portion of white oil is 8: (1 to 2): (26 to 28).

[0054] Example 5: As an optimization of the above example, in the second step, the mass ratio of polybutadiene to dicumyl peroxide is 8:(0.02 to 0.04).

[0055] Example 6: As an optimization of the above example, in the third step, the mass ratio of polybutadiene, sulfonated ricinoleic acid and mixed amine is 8: (5 to 7): (1.5 to 2.5).

[0056] Example 7: As an optimization of the above example, in the third step, the mixed amine is a mixture of diethylenetriamine and triethylenetetramine in a mass ratio of (1.5 to 2.5):1.

[0057] Example 8: As an optimization of the above example, in the fourth step, the mass ratio of polybutadiene, epibromohydrin and the remaining white oil is 8: (0.8 to 1.0): (10 to 12).

[0058] Example 9: As an optimization of the above example, in the second step, during the graft polymerization reaction, the reaction temperature is 130° C. to 150° C., and the reaction time is 3 h to 4 h.

[0059] Example 10: As an optimization of the above example, in the third step, during the amidation reaction, the reaction temperature is 90°C to 110°C, and the reaction time is 2h to 3h.

[0060] Example 11: As an optimization of the above example, in the fourth step, during the reaction, the reaction temperature is 50°C to 60°C, and the reaction time is 2h to 3h.

[0061] In this invention, ricinoleic acid, a raw material containing a secondary hydroxyl group (12-hydroxy-9-octadecenoic acid), is used as the starting material. The sulfonation reaction follows an electrophilic substitution mechanism. Chlorosulfonic acid (ClSO₃H) decomposes at low temperatures into SO₃ (a strong electrophile) and HCl. SO₃ attacks the hydroxyl oxygen atom, forming a sulfonate intermediate. Subsequently, proton transfer generates a sulfonic acid group (-SO₃H). Carboxylic acid has a low degree of dissociation at low temperatures and is less reactive than the hydroxyl group. Therefore, low temperatures suppress the side reaction between the carboxylic acid group (-COOH) and SO₃ (forming a sulfonated carboxylic acid). The sulfonated ricinoleic acid molecule contains both a sulfonic acid group (hydrophilic) and a long carbon chain (hydrophobic), giving it amphiphilic properties.

[0062] The 1,2-structure of polybutadiene contains isolated double bonds, making it more susceptible to free radical grafting. Dicumyl peroxide homolytically breaks down at 130°C into two tert-butyloxy radicals: (C6H5C(CH3)2O)2 → 2C6H5C(CH3)2O⋅. The tert-butyloxy radical captures the allylic hydrogen atom of the polybutadiene chain, generating a macromolecular radical: PB-CH2-CH2-CH2-CH2 → PB-CH2-CH⋅+H⋅. High temperatures accelerate chain transfer, and the macromolecular radical attacks the double bond in maleic anhydride, opening it and forming a grafted chain: PB-CH2-CH⋅+MA → PB-CH2-CH-(MA)⋅. White oil, as an inert solvent, reduces system viscosity and prevents crosslinking and gelation of the grafted product.

[0063] The anhydride groups in the white oil solution of maleic anhydride-grafted polybutadiene react with mixed amines to form amide bonds and carboxylic acids: PB-g-MA + H2N-R → PB-g-MA-NH-R + HOOC-CH2-COOH. This introduces carboxylic acid groups, further increasing hydrophilicity. The amine groups in the amide bonds act as nucleophiles to further attack the epoxy ring in the epibromohydrin, forming secondary amines and hydroxyl groups: NH-R + CH2(O)CH2Br → NH-R-CH2-CH(OH)-CH2Br. The bromine atoms in the epibromohydrin serve as subsequent reaction sites (synergistically with the subsequent primary emulsifier), while the white oil (a long-chain alkane) binds to the hydrophobic segments of the polybutadiene through van der Waals forces, forming a "solvent shell" that encapsulates the cross-linked network and inhibits molecular chain entanglement. Ultimately, the synthetic auxiliary emulsifier for oil-based drilling fluid is a multi-component complex, in which the hydrophilic part includes sulfonic acid groups, carboxylic acid groups, amino groups and hydroxyl groups generated by epoxy ring opening; the hydrophobic part includes polybutadiene chains, white oil hydrocarbon chains, etc. The polybutadiene chain anchors the oil phase, the sulfonic acid group ionizes (-SO3⁻) to form a double layer, and the amino group enhances the interfacial film strength through hydrogen bonds.

[0064] Finally, the auxiliary emulsifier for oil-based drilling fluid prepared with sulfonated ricinoleic acid, white oil solution of maleic anhydride grafted polybutadiene, mixed amine and epibromopropane as main raw materials has stable high temperature performance and excellent salt resistance.

[0065] Example 12:

[0066] The sulfonated ricinoleic acid is obtained by the following method (see Table 1 for the ratio of raw materials):

[0067] S1, add 100 g of ricinoleic acid and 400 g of dichloromethane to a dry reactor, and cool the reactor to 0°C to 5°C in an ice bath;

[0068] S2, add 20 g of chlorosulfonic acid dropwise to the reactor, control the temperature to 0°C to 10°C to avoid side reactions, and after the addition is complete, heat the reactor to 25°C and stir for 2 h to obtain a mixed solution;

[0069] S3, the mixed solution was distilled under reduced pressure (60°C / 0.1 MPa) to remove the solvent, and then washed with anhydrous ethanol 3 to 4 times, and vacuum dried to obtain sulfonated ricinoleic acid.

[0070] The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0071] In the first step, under a nitrogen atmosphere, 80 g of polybutadiene (Mn=3500, 1,2-structure content 70%), 10 g of maleic anhydride, and 270 g of a portion of white oil were mixed and stirred until dissolved to obtain a mixture;

[0072] In the second step, 0.2 g of dicumyl peroxide was added to the mixture, and a graft polymerization reaction was carried out at a temperature of 130° C. for 3 hours, and then cooled to 50° C. to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0073] In the third step, 50 g of sulfonated ricinoleic acid and 15 g of mixed amine (9 g of diethylenetriamine and 6 g of triethylenetetramine) were added to the white oil solution of maleic anhydride-grafted polybutadiene. The mixture was reacted at 90°C for 2 h to complete the amidation and obtain the product.

[0074] The fourth step is to cool the product to 50°C, add 8g of epibromopropane to the product, react for 2h, and then add the remaining amount of white oil 110g and stir homogeneously to obtain an amber liquid, which is the auxiliary emulsifier for oil-based drilling fluid.

[0075] Example 13:

[0076] The sulfonated ricinoleic acid is obtained by the following method (see Table 1 for the ratio of raw materials):

[0077] S1, add 100 g of ricinoleic acid and 400 g of dichloromethane to a dry reactor, and cool the reactor to 0°C to 5°C in an ice bath;

[0078] S2, add 25 g of chlorosulfonic acid dropwise to the reactor, control the temperature to 0°C to 10°C to avoid side reactions, and after the addition is complete, heat the reactor to 25°C and stir for 3 h to obtain a mixed solution;

[0079] S3, the mixed solution was distilled under reduced pressure (60°C / 0.1 MPa) to remove the solvent, and then washed with anhydrous ethanol 3 to 4 times, and vacuum dried to obtain sulfonated ricinoleic acid.

[0080] The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0081] In the first step, under a nitrogen atmosphere, 80 g of polybutadiene (Mn=3500, 1,2-structure content 70%), 20 g of maleic anhydride, and 270 g of a portion of white oil were mixed and stirred until dissolved to obtain a mixture;

[0082] In the second step, 0.3 g of dicumyl peroxide was added to the mixture, and a graft polymerization reaction was carried out at a temperature of 140° C. for 3 hours, and then cooled to 60° C. to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0083] In the third step, 60 g of sulfonated ricinoleic acid and 20 g of mixed amine (14 g of diethylenetriamine and 6 g of triethylenetetramine) were added to the white oil solution of maleic anhydride-grafted polybutadiene, and the mixture was reacted at 90°C for 3 h to complete the amidation and obtain the product;

[0084] The fourth step is to cool the product to 60°C, add 10g of epibromopropane to the product, react for 3h, and then add the remaining amount of white oil 110g and stir homogeneously to obtain an amber liquid, which is the auxiliary emulsifier for oil-based drilling fluid.

[0085] Example 14:

[0086] The sulfonated ricinoleic acid is obtained by the following method (see Table 1 for the ratio of raw materials):

[0087] S1, add 100 g of ricinoleic acid and 400 g of dichloromethane to a dry reactor, and cool the reactor to 0°C to 5°C in an ice bath;

[0088] S2, add 25 g of chlorosulfonic acid dropwise to the reactor, control the temperature to 0°C to 10°C to avoid side reactions, and after the addition is complete, heat the reactor to 25°C and stir for 2 h to obtain a mixed solution;

[0089] S3, the mixed solution was distilled under reduced pressure (60°C / 0.1 MPa) to remove the solvent, and then washed with anhydrous ethanol 3 to 4 times, and vacuum dried to obtain sulfonated ricinoleic acid.

[0090] The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0091] In the first step, under a nitrogen atmosphere, 80 g of polybutadiene (Mn=3500, 1,2-structure content 70%), 15 g of maleic anhydride, and 270 g of a portion of white oil were mixed and stirred until dissolved to obtain a mixture;

[0092] In the second step, 0.3 g of dicumyl peroxide was added to the mixture, and a graft polymerization reaction was carried out at a temperature of 140° C. for 3 hours, and then cooled to 50° C. to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0093] In the third step, 65 g of sulfonated ricinoleic acid and 20 g of mixed amine (12 g of diethylenetriamine and 8 g of triethylenetetramine) were added to the white oil solution of maleic anhydride-grafted polybutadiene. The mixture was reacted at 100°C for 3 h to complete the amidation and obtain the product.

[0094] The fourth step is to cool the product to 50°C, add 10g of epibromopropane to the product, react for 3h, and then add the remaining amount of white oil 110g and stir homogeneously to obtain an amber liquid, which is the auxiliary emulsifier for oil-based drilling fluid.

[0095] Example 15:

[0096] The sulfonated ricinoleic acid is obtained by the following method (see Table 1 for the ratio of raw materials):

[0097] S1, add 100 g of ricinoleic acid and 400 g of dichloromethane to a dry reactor, and cool the reactor to 0°C to 5°C in an ice bath;

[0098] S2, add 25 g of chlorosulfonic acid dropwise to the reactor, control the temperature to 0°C to 10°C to avoid side reactions, and after the addition is complete, heat the reactor to 25°C and stir for 2 h to obtain a mixed solution;

[0099] S3, the mixed solution was distilled under reduced pressure (60°C / 0.1 MPa) to remove the solvent, and then washed with anhydrous ethanol 3 to 4 times, and vacuum dried to obtain sulfonated ricinoleic acid.

[0100] The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0101] In the first step, under a nitrogen atmosphere, 80 g of polybutadiene (Mn=3500, 1,2-structure content 70%), 15 g of maleic anhydride, and 270 g of a portion of white oil were mixed and stirred until dissolved to obtain a mixture;

[0102] In the second step, 0.3 g of dicumyl peroxide was added to the mixture, and a graft polymerization reaction was carried out at a temperature of 140° C. for 3 hours, and then cooled to 50° C. to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0103] In the third step, 65 g of sulfonated ricinoleic acid and 15 g of mixed amine (9 g of diethylenetriamine and 6 g of triethylenetetramine) were added to the white oil solution of maleic anhydride-grafted polybutadiene. The mixture was reacted at 100°C for 3 h to complete the amidation and obtain the product.

[0104] The fourth step is to cool the product to 50°C, add 8g of epibromopropane to the product, react for 3h, and then add the remaining amount of white oil 110g and stir until homogeneous to obtain an amber liquid, which is the auxiliary emulsifier for oil-based drilling fluid.

[0105] Example 16:

[0106] The sulfonated ricinoleic acid is obtained by the following method (see Table 1 for the ratio of raw materials):

[0107] S1, add 100 g of ricinoleic acid and 400 g of dichloromethane to a dry reactor, and cool the reactor to 0°C to 5°C in an ice bath;

[0108] S2, add 30 g of chlorosulfonic acid dropwise to the reactor, control the temperature to 0°C to 10°C to avoid side reactions, and after the addition is complete, heat the reactor to 25°C and stir for 3 h to obtain a mixed solution;

[0109] S3, the mixed solution was distilled under reduced pressure (60°C / 0.1 MPa) to remove the solvent, and then washed with anhydrous ethanol 3 to 4 times, and vacuum dried to obtain sulfonated ricinoleic acid.

[0110] The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0111] In the first step, under a nitrogen atmosphere, 80 g of polybutadiene (Mn=3500, 1,2-structure content 70%), 15 g of maleic anhydride, and 270 g of a portion of white oil were mixed and stirred until dissolved to obtain a mixture;

[0112] In the second step, 0.3 g of dicumyl peroxide was added to the mixture, and a graft polymerization reaction was carried out at a temperature of 140° C. for 3 hours, and then cooled to 50° C. to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0113] In the third step, 70 g of sulfonated ricinoleic acid and 25 g of mixed amine (15 g of diethylenetriamine and 10 g of triethylenetetramine) were added to the white oil solution of maleic anhydride grafted polybutadiene, and the mixture was reacted at 100°C for 3 h to complete the amidation and obtain the product;

[0114] The fourth step is to cool the product to 60°C, add 10g of epibromopropane to the product, react for 3h, and then add the remaining amount of white oil 110g and stir homogeneously to obtain an amber liquid, which is the auxiliary emulsifier for oil-based drilling fluid.

[0115] Example 17:

[0116] The sulfonated ricinoleic acid is obtained by the following method (see Table 1 for the ratio of raw materials):

[0117] S1, add 100 g of ricinoleic acid and 400 g of dichloromethane to a dry reactor, and cool the reactor to 0°C to 5°C in an ice bath;

[0118] S2, add 25 g of chlorosulfonic acid dropwise to the reactor, control the temperature to 0°C to 10°C to avoid side reactions, and after the addition is complete, heat the reactor to 25°C and stir for 2 h to obtain a mixed solution;

[0119] S3, the mixed solution was distilled under reduced pressure (60°C / 0.1 MPa) to remove the solvent, and then washed with anhydrous ethanol 3 to 4 times, and vacuum dried to obtain sulfonated ricinoleic acid.

[0120] The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0121] In the first step, under a nitrogen atmosphere, 80 g of polybutadiene (Mn=3500, 1,2-structure content 70%), 15 g of maleic anhydride, and 270 g of a portion of white oil were mixed and stirred until dissolved to obtain a mixture;

[0122] In the second step, 0.4 g of dicumyl peroxide was added to the mixture, and a graft polymerization reaction was carried out at a temperature of 150° C. for 3 hours, and then cooled to 50° C. to obtain a white oil solution of maleic anhydride grafted polybutadiene;

[0123] In the third step, 70 g of sulfonated ricinoleic acid and 20 g of mixed amine (12 g of diethylenetriamine and 8 g of triethylenetetramine) were added to the white oil solution of maleic anhydride-grafted polybutadiene. The mixture was reacted at 110°C for 3 h to complete the amidation and obtain the product.

[0124] The fourth step is to cool the product to 50°C, add 8g of epibromopropane to the product, react for 2h, and then add the remaining amount of white oil 110g and stir homogeneously to obtain an amber liquid, which is the auxiliary emulsifier for oil-based drilling fluid.

[0125] Comparative Example 1:

[0126] The sulfonated ricinoleic acid is obtained by the following method (see Table 2 for the ratio of raw materials):

[0127] S1, add 100 g of ricinoleic acid and 400 g of dichloromethane to a dry reactor, and cool the reactor to 0°C to 5°C in an ice bath;

[0128] S2, add 25 g of chlorosulfonic acid dropwise to the reactor, control the temperature to 0°C to 10°C to avoid side reactions, and after the addition is complete, heat the reactor to 25°C and stir for 4 hours to obtain a mixed solution;

[0129] S3, the mixed solution was distilled under reduced pressure (60°C / 0.1 MPa) to remove the solvent, and then washed with anhydrous ethanol 3 to 4 times, and vacuum dried to obtain sulfonated ricinoleic acid.

[0130] The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0131] In the first step, under a nitrogen atmosphere, 80 g of polybutadiene (Mn=3500, 1,2-structure content 70%), 20 g of itaconic anhydride, and 270 g of a portion of white oil were mixed and stirred until dissolved to obtain a mixture;

[0132] In the second step, 0.3 g of dicumyl peroxide was added to the mixture, and a graft polymerization reaction was carried out at a temperature of 130° C. for 4 hours, and then cooled to 60° C. to obtain a white oil solution of itaconic anhydride grafted polybutadiene;

[0133] In the third step, 70 g of sulfonated ricinoleic acid and 20 g of mixed amine (12 g of diethylenetriamine and 8 g of triethylenetetramine) were added to the white oil solution of itaconic anhydride grafted polybutadiene, and the mixture was reacted at 100°C for 2 h to complete the amidation and obtain the product;

[0134] The fourth step is to cool the product to 50°C, add 10g of epibromopropane to the product, react for 2h, and then add the remaining amount of white oil 110g and stir homogeneously to obtain an amber liquid, which is the auxiliary emulsifier for oil-based drilling fluid.

[0135] Comparative Example 2:

[0136] The sulfonated ricinoleic acid is obtained by the following method (see Table 2 for the ratio of raw materials):

[0137] S1, add 100 g of ricinoleic acid and 400 g of dichloromethane to a dry reactor, and cool the reactor to 0°C to 5°C in an ice bath;

[0138] S2, add 25 g of chlorosulfonic acid dropwise to the reactor, control the temperature to 0°C to 10°C to avoid side reactions, and after the addition is complete, heat the reactor to 25°C and stir for 2 h to obtain a mixed solution;

[0139] S3, the mixed solution was distilled under reduced pressure (60°C / 0.1 MPa) to remove the solvent, and then washed with anhydrous ethanol 3 to 4 times, and vacuum dried to obtain sulfonated ricinoleic acid.

[0140] The auxiliary emulsifier for oil-based drilling fluid is obtained by the following method:

[0141] In the first step, under a nitrogen atmosphere, 80 g of polybutadiene (Mn=3500, 1,2-structure content 70%), 15 g of itaconic anhydride, and 270 g of a portion of white oil were mixed and stirred until dissolved to obtain a mixture;

[0142] In the second step, 0.3 g of dicumyl peroxide was added to the mixture, and a graft polymerization reaction was carried out at a temperature of 140° C. for 3 hours, and then cooled to 50° C. to obtain a white oil solution of itaconic anhydride grafted polybutadiene;

[0143] In the third step, 60 g of sulfonated ricinoleic acid and 25 g of mixed amine (15 g of diethylenetriamine and 10 g of triethylenetetramine) were added to the white oil solution of itaconic anhydride grafted polybutadiene, and the mixture was reacted at 100°C for 3 h to complete the amidation and obtain the product;

[0144] The fourth step is to cool the product to 50°C, add 10g of epibromopropane to the product, react for 3h, and then add the remaining amount of white oil 110g and stir homogeneously to obtain an amber liquid, which is the auxiliary emulsifier for oil-based drilling fluid.

[0145] Comparative Example 3:

[0146] The auxiliary emulsifier for oil-based drilling fluid differs from Example 12 of the present invention in that the sulfonated ricinoleic acid is replaced with sulfonated coconut oleic acid, and the raw material ricinoleic acid in the preparation method of sulfonated ricinoleic acid is replaced with coconut oleic acid, while the remaining steps remain unchanged (refer to Table 2 for the ratio of the raw materials).

[0147] Comparative Example 4:

[0148] The auxiliary emulsifier for oil-based drilling fluid differs from Example 13 of the present invention in that the sulfonated ricinoleic acid is replaced with sulfonated coconut oleic acid, and the raw material ricinoleic acid in the preparation method of sulfonated ricinoleic acid is replaced with coconut oleic acid, and the remaining steps remain unchanged (refer to Table 2 for the ratio of the raw materials).

[0149] Comparative Example 5:

[0150] The auxiliary emulsifier for oil-based drilling fluid differs from Comparative Example 1 of the present invention in that the sulfonated ricinoleic acid is replaced by sulfonated coconut oleic acid, and the raw material ricinoleic acid in the preparation method of sulfonated ricinoleic acid is replaced by coconut oleic acid, while the remaining steps remain unchanged (refer to Table 2 for the proportions of the raw materials).

[0151] Comparative Example 6:

[0152] The auxiliary emulsifier for oil-based drilling fluid differs from Comparative Example 2 of the present invention in that the sulfonated ricinoleic acid is replaced by sulfonated coconut oleic acid, and the raw material ricinoleic acid in the preparation method of sulfonated ricinoleic acid is replaced by coconut oleic acid, while the remaining steps remain unchanged (refer to Table 2 for the proportions of the raw materials).

[0153] Comparative Example 7:

[0154] The existing auxiliary emulsifier XZ-OFR is used.

[0155] Experimental Example 1: Basic properties of the auxiliary emulsifier for oil-based drilling fluid of the present invention.

[0156] Experimental Method: The oil-based drilling fluids prepared in Examples 12 to 17 of the present invention were formulated into emulsions using a co-emulsifier. The properties of the emulsions were tested before and after hot rolling at 150°C, including apparent viscosity, plastic viscosity, and demulsification voltage. Comparative Examples 1 to 7 were used as controls.

[0157] The preparation process of the emulsion is as follows (refer to standard Q / SY 17012-2024):

[0158] (1) 4% of the auxiliary emulsifier for oil-based drilling fluid prepared in Examples 12 to 17 of the present invention and the auxiliary emulsifier for oil-based drilling fluid prepared in Comparative Examples 1 to 7 of the present invention were added to 320 mL of 0# diesel, and stirred at high speed for 20 minutes at a speed of 11000 rpm;

[0159] (2) Under high-speed stirring, add 80 mL of 25% CaCl2 saline solution and continue high-speed stirring for 20 minutes;

[0160] (3) Under high-speed stirring, 3% CaO and 1% organic soil were added and stirred at high speed for 20 min to obtain emulsions L1 to L13, respectively.

[0161] Experimental Results: Emulsions prepared using the auxiliary emulsifiers for oil-based drilling fluids prepared in Examples 12 to 17 of the present invention as raw materials are designated L1 to L6, and emulsions prepared using the auxiliary emulsifiers for oil-based drilling fluids prepared in Comparative Examples 1 to 7 of the present invention as raw materials are designated L7 to L13. The performance indicators of emulsions L1 to L13 before, after, and after 16 hours and 72 hours of hot rolling at 150°C are shown in Table 3. The differences in the performance indicators of emulsions L1 to L13 between before and after 16 hours, after 16 hours and after 72 hours, and before and after 72 hours of hot rolling at 150°C are shown in Table 4.

[0162] As can be seen from Table 3, the initial values ​​of the demulsification voltages of emulsions L1 (Example 12) to L6 (Example 17) of the present invention before hot rolling were all maintained between 580 V and 700 V, indicating relatively high demulsification voltages; while the demulsification voltages of emulsions L7 (Comparative Example 1) to L10 (Comparative Example 4) after hot rolling at 150°C for 72 h were all lower than 400 V, indicating that the demulsification performance did not meet the requirements of industry standards; the demulsification voltages of emulsions L11 (Comparative Example 5) to L12 (Comparative Example 6) were higher than 400 V, but also lower than those of emulsions L1 (Example 12) to L6 (Example 17) of the present invention.

[0163] As can be seen from Table 4, the differences in apparent viscosity before and after hot rolling and the differences in plastic viscosity before and after hot rolling of emulsion L11 (Comparative Example 5) to emulsion L12 (Comparative Example 6) and emulsion L13 (auxiliary emulsifier XZ-OFR) are larger, indicating that their rheological properties are poor. At the same time, the differences in demulsification voltage before and after hot rolling of emulsion L11 (Comparative Example 5) to emulsion L12 (Comparative Example 6) and emulsion L13 (auxiliary emulsifier XZ-OFR) are also larger, indicating that their electrical stability is poor.

[0164] The apparent viscosity and plastic viscosity of emulsions L1 (Example 12) through L6 (Example 17) of the present invention varied within a narrow range before and after hot rolling, indicating superior rheological properties. Furthermore, the demulsification voltage of emulsions L1 (Example 12) through L6 (Example 17) of the present invention also varied within a narrow range before and after hot rolling, demonstrating superior electrical stability. Therefore, compared to emulsions L11 (Comparative Example 5) through L12 (Comparative Example 6), as well as emulsion L13 (co-emulsifier XZ-OFR), emulsions L1 (Example 12) through L6 (Example 17) of the present invention exhibited superior rheological and electrical stability. Specifically, considering the comprehensive changes in apparent viscosity, plastic viscosity, and demulsification voltage before and after hot rolling, the performance of emulsion L3 (Example 14) was particularly outstanding.

[0165] Experimental Example 2: Salt resistance of the auxiliary emulsifier for oil-based drilling fluid of the present invention.

[0166] Experimental method: The oil-based drilling fluids prepared in Examples 12 to 17 of the present invention were formulated into emulsions with auxiliary emulsifiers, and the salt resistance of the emulsions was tested. Meanwhile, Comparative Examples 1 to 7 were used as controls.

[0167] The preparation process of the emulsion is as follows (standard Q / SY 17012-2024):

[0168] (1) 18 g of auxiliary emulsifiers for oil-based drilling fluids prepared in Examples 12 to 17 of the present invention and auxiliary emulsifiers for oil-based drilling fluids prepared in Comparative Examples 1 to 7 of the present invention were added to 285 mL of 0# diesel, and stirred at high speed for 20 min at a speed of 11000 rpm;

[0169] (2) Add 15 mL of 25% CaCl2 saline solution under high-speed stirring and continue stirring at high speed for 20 minutes;

[0170] (3) Add 15 g of CaO and 6 g of organic soil under high-speed stirring and stir at high speed for 20 min to obtain an emulsion;

[0171] (4) Weigh 35 g of sodium chloride and 2 g of calcium chloride and dissolve them in 100 mL of distilled water. Stir with a glass rod until they are completely dissolved to obtain a saline solution.

[0172] (5) 90 mL of saline solution was added to the emulsion and stirred at 11,000 rpm for 10 min using a high-speed stirrer to obtain emulsions K1 to K13, respectively.

[0173] Experimental Results: Emulsions prepared using the auxiliary emulsifiers for oil-based drilling fluids prepared in Examples 12 to 17 of the present invention as raw materials are designated K1 to K6, and emulsions prepared using the auxiliary emulsifiers for oil-based drilling fluids prepared in Comparative Examples 1 to 7 of the present invention as raw materials are designated K7 to K13. The salt tolerance of emulsions K1 to K13 is shown in Table 5. As can be seen from Table 5, compared to emulsions K7 (Comparative Example 1) to K13 (auxiliary emulsifier XZ-OFR), emulsions K1 (Example 12) to K6 (Example 17) of the present invention have higher demulsification voltages, indicating that emulsions K1 (Example 12) to K6 (Example 17) of the present invention have superior salt tolerance, with emulsion K3 (Example 14) exhibiting particularly outstanding performance.

[0174] It can be seen from Experimental Examples 1 and 2 that the emulsion prepared with the auxiliary emulsifier for oil-based drilling fluid prepared by the present invention has good rheological stability and electrical stability at high temperature and good salt resistance.

[0175] In summary, the auxiliary emulsifier for oil-based drilling fluid of the present invention is prepared with sulfonated ricinoleic acid, white oil solution of maleic anhydride grafted polybutadiene, mixed amine and epibromopropane as main raw materials, and has stable high-temperature performance and excellent salt resistance.

[0176] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Non-essential technical features can be added or removed according to actual needs to meet the requirements of different situations.

[0177] Table 1

[0178] .

[0179] Table 2

[0180] .

[0181] Table 3

[0182] .

[0183] Table 4

[0184] .

[0185] Table 5

[0186] .

Claims

1. A secondary emulsifier for oil-based drilling fluid, characterized in that Obtained as follows: In the first step, polybutadiene, maleic anhydride and a portion of white oil are mixed and stirred under a nitrogen atmosphere until dissolved to obtain a mixture; In the second step, dicumyl peroxide is added to the mixture to cause graft polymerization reaction to obtain a white oil solution of maleic anhydride grafted polybutadiene; The third step is to add sulfonated ricinoleic acid to the white oil solution of maleic anhydride grafted polybutadiene, and then add a mixed amine to carry out an amidation reaction to obtain a product, wherein the sulfonated ricinoleic acid is obtained by a sulfonation reaction of ricinoleic acid and chlorosulfonic acid. The specific preparation method is as follows: S1, placing ricinoleic acid and dichloromethane in a reactor, and lowering the temperature of the reactor to 0°C to 5°C; S2, adding chlorosulfonic acid to the reactor, controlling the temperature to 0°C to 10°C, and after the addition is complete, heating the reactor to 25°C to 30°C, stirring and reacting for 2h to 3h to obtain a mixed solution; S3, distilling the mixed solution under reduced pressure, and then washing it with anhydrous ethanol 3 to 4 times, and vacuum drying to obtain the sulfonated ricinoleic acid; the mixed amine is a mixture of diethylenetriamine and triethylenetetramine with a mass ratio of 1.5 to 2.5:1; In the fourth step, epibromopropane is added to the product to react, and then the remaining amount of white oil is added and stirred to obtain an auxiliary emulsifier for oil-based drilling fluid.

2. The auxiliary emulsifier for oil-based drilling fluid according to claim 1, characterized in that In step S1, the mass ratio of ricinoleic acid to dichloromethane is 10:35 to 45. In step S2, the mass ratio of ricinoleic acid to chlorosulfonic acid is 10:2 to 3.

3. The auxiliary emulsifier for oil-based drilling fluid according to claim 1 or 2, characterized in that In the first step, the mass ratio of polybutadiene, maleic anhydride and a portion of white oil is 8:1 to 2:26 to 28.

4. The auxiliary emulsifier for oil-based drilling fluid according to claim 1 or 2, characterized in that In the second step, the mass ratio of polybutadiene to dicumyl peroxide is 8:0.02 to 0.

04.

5. The auxiliary emulsifier for oil-based drilling fluid according to claim 3, characterized in that In the second step, the mass ratio of polybutadiene to dicumyl peroxide is 8:0.02 to 0.

04.

6. The auxiliary emulsifier for oil-based drilling fluid according to claim 1, 2 or 5, characterized in that In the third step, the mass ratio of polybutadiene, sulfonated ricinoleic acid and mixed amine is 8:5 to 7:1.5 to 2.5; or / and, in the fourth step, the mass ratio of polybutadiene, epibromohydrin and the remainder of white oil is 8:0.8 to 1.0:10 to 12.

7. The auxiliary emulsifier for oil-based drilling fluid according to claim 3, characterized in that In the third step, the mass ratio of polybutadiene, sulfonated ricinoleic acid and mixed amine is 8:5 to 7:1.5 to 2.5; or / and, in the fourth step, the mass ratio of polybutadiene, epibromohydrin and the remainder of white oil is 8:0.8 to 1.0:10 to 12.

8. The auxiliary emulsifier for oil-based drilling fluid according to claim 4, characterized in that In the third step, the mass ratio of polybutadiene, sulfonated ricinoleic acid and mixed amine is 8:5 to 7:1.5 to 2.5; or / and, in the fourth step, the mass ratio of polybutadiene, epibromohydrin and the remainder of white oil is 8:0.8 to 1.0:10 to 12.

9. The auxiliary emulsifier for oil-based drilling fluid according to claim 1, 2, 5, 7 or 8, characterized in that In the second step, during the graft polymerization reaction, the reaction temperature is 130°C to 150°C, and the reaction time is 3h to 4h; or / and, during the amidation reaction in the third step, the reaction temperature is 90°C to 110°C, and the reaction time is 2h to 3h; or / and, during the reaction in the fourth step, the reaction temperature is 50°C to 60°C, and the reaction time is 2h to 3h.

10. The auxiliary emulsifier for oil-based drilling fluid according to claim 6, characterized in that In the second step, during the graft polymerization reaction, the reaction temperature is 130°C to 150°C, and the reaction time is 3h to 4h; or / and, during the amidation reaction in the third step, the reaction temperature is 90°C to 110°C, and the reaction time is 2h to 3h; or / and, during the reaction in the fourth step, the reaction temperature is 50°C to 60°C, and the reaction time is 2h to 3h.

11. A method for preparing a secondary emulsifier for oil-based drilling fluid according to any one of claims 2 to 10, characterized in that Proceed as follows: In the first step, polybutadiene, maleic anhydride and a portion of white oil are mixed and stirred under a nitrogen atmosphere until dissolved to obtain a mixture; In the second step, dicumyl peroxide is added to the mixture to cause graft polymerization reaction to obtain a white oil solution of maleic anhydride grafted polybutadiene; The third step is to add sulfonated ricinoleic acid to the white oil solution of maleic anhydride grafted polybutadiene, and then add a mixed amine to carry out an amidation reaction to obtain a product, wherein the sulfonated ricinoleic acid is obtained by a sulfonation reaction of ricinoleic acid and chlorosulfonic acid. The specific preparation method is as follows: S1, placing ricinoleic acid and dichloromethane in a reactor, and lowering the temperature of the reactor to 0°C to 5°C; S2, adding chlorosulfonic acid to the reactor, controlling the temperature to 0°C to 10°C, and after the addition is complete, heating the reactor to 25°C to 30°C, stirring and reacting for 2h to 3h to obtain a mixed solution; S3, distilling the mixed solution under reduced pressure, and then washing it with anhydrous ethanol 3 to 4 times, and vacuum drying to obtain the sulfonated ricinoleic acid; the mixed amine is a mixture of diethylenetriamine and triethylenetetramine with a mass ratio of 1.5 to 2.5:1; In the fourth step, epibromopropane is added to the product to react, and then the remaining amount of white oil is added and stirred to obtain an auxiliary emulsifier for oil-based drilling fluid.