Compound with temperature-resistant and calcium-magnesium-resistant functions as well as preparation method and application thereof

Abstract

The invention relates to the field of surfactants for oil displacement, and discloses a compound with temperature-resistant and calcium-magnesium-resistant functions as well as a preparation method and application thereof, the compound is characterized in that the compound has a chemical structure as shown in a formula 1, and when the compound is used as a surfactant, the effects of high temperature resistance, good calcium-magnesium resistance, good interfacial activity and high oil washing efficiency can be achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil displacement surfactants, in particular to a compound with temperature resistance and calcium and magnesium resistance function and a preparation method and application thereof. BACKGROUND

[0002] The increasing global oil consumption and the complex international situation make the contradiction between supply and demand of oil resources more prominent. Stable oil supply has become a top priority to ensure China's energy security. Therefore, the domestic oil and gas industry continues to improve the exploration and development of oil resources and the intensity of increasing reserves and production. Most of China's old oilfields have entered the tertiary oil recovery stage. Further development and innovation of existing displacement technology and ultimately improving recovery are effective ways to alleviate the current and future oil supply and demand contradiction in China.

[0003] Chemical flooding is one of the dominant technologies for improving oil recovery in tertiary oil recovery, and surfactant flooding technology is an important branch of chemical flooding technology. This technology mainly achieves improved recovery by reducing oil-water interfacial tension and changing the wettability of reservoir rocks. After a large number of oilfields at home and abroad are displaced by surfactants, they can increase the recovery by 3-10% based on water flooding. In existing surfactant flooding technology, single anionic surfactants are mostly used, which can basically meet the development needs of ordinary reservoirs in practical applications. However, as oilfield development reaches the late stage of its life cycle, the downhole formation conditions become more and more complex. When single anionic surfactants encounter high concentrations of calcium and magnesium ions in the formation, they are prone to form precipitates under the action of static electricity, and cannot maintain a low oil-water interfacial tension. In addition, conventional single anionic surfactants are prone to decomposition at high temperatures, and cannot be applied to high-temperature reservoirs.

[0004] By contrast, gemini surfactants have the characteristics of high surface activity, strong solubilizing ability, good emulsifying ability, and good wettability, and can maintain good oil displacement effect in complex reservoir environments with high temperature and high calcium and magnesium. As a chemical displacement agent, it has strong application potential. The existing gemini surfactants are limited in type, have no obvious performance advantages, and have insufficient application potential in chemical flooding. Therefore, it is urgent to design gemini surfactants with new structures and develop efficient synthesis routes to provide stable and high-performance displacement agents for improving the recovery of high-calcium and high-magnesium reservoirs. SUMMARY

[0005] The purpose of the present application is to overcome the problems of poor high-temperature resistance, calcium and magnesium resistance, interfacial performance and low oil washing efficiency in the prior art, and to provide a compound with temperature resistance and calcium and magnesium resistance function and a preparation method and application thereof.

[0006] In order to achieve the above-mentioned purpose, the present application provides a compound with temperature resistance and calcium and magnesium resistance function, characterized in that the compound has a chemical structure shown in formula 1:

[0007]

[0008] wherein R1 and R1' are each independently selected from C8-C18 alkyl;

[0009] R2, R2', R3 and R3' are each independently selected from C1-C4 alkyl;

[0010] b, a', b, b', c and c' are each independently selected from an integer from 1 to 6;

[0011] d is selected from an integer from 1 to 10;

[0012] M and M' are each independently selected from H or an alkali metal element;

[0013] X is selected from halogen.

[0014] The second aspect of the present application provides a preparation method of a compound with temperature-resistant and calcium-magnesium-resistant functions, characterized in that the method comprises:

[0015] (1) subjecting at least one of compounds A shown in formula A1 to a quaternary ammonium reaction with at least one of compounds B shown in formula B1;

[0016] (2) subjecting the product obtained in the quaternary ammonium reaction in step (1) to a coupling reaction with compound C to obtain a compound shown in formula 1;

[0017]

[0018] wherein the compound shown in formula 1, R1, R2, R3, a, b, c, d, M and X correspond to the same definitions as those in the first aspect of the present application.

[0019] The third aspect of the present application provides an application of the compound in the first aspect of the present application in improving oil washing rate.

[0020] Through the above technical solution, the present application has the following beneficial effects:

[0021] (1) The preparation process of the compound provided by the present application has mild reaction conditions, simple reaction process and high reaction yield.

[0022] (2) The hydrophobic part of the compound provided by the present application contains both aryl and long alkyl chain structures, which can significantly improve the oil washing rate of crude oil.

[0023] (3) The compound provided by the present application can maintain strong anti-adsorption performance under high temperature and high calcium-magnesium conditions. After repeating the oil washing experiment for many times, the oil washing rate can still be maintained at a high level.

[0024] (4) The compound provided by the present invention has strong high temperature resistance, and the temperature resistance limit can reach more than 300℃.

[0025] (5) The compound provided by the present invention has high surface activity, and the surface tension of a 0.8 wt% aqueous solution of the compound can be as low as 27 mN / m at 75 °C. Attached Figure Description

[0026] Figure 1 The NMR results are for intermediate K prepared in Example 1.

[0027] Figure 2 The NMR results are for the reaction intermediate L prepared in Example 1.

[0028] Figure 3 The NMR results are for the compound of formula 1-1 prepared in Example 1;

[0029] Figure 4 The NMR results are for the compounds of formula 1-2 prepared in Example 2;

[0030] Figure 5 NMR detection results for the compounds of formulas 1-3 prepared in Example 3;

[0031] Figure 6 The NMR results are for the compounds of formulas 1-4 prepared in Example 4;

[0032] Figure 7 The NMR results are for the compounds of Formulas 1-5 prepared in Comparative Example 1.

[0033] Figure 8 The TG (blue) and DTG (red) curves of the compound synthesized in Example 1 are shown.

[0034] Figure 9 Surface tension of a 0.8 wt% solution of the synthetic compound from Example 1 and a control at different temperatures;

[0035] Figure 10 The oil wash rate of the compound solutions synthesized in Example 1 with different mass concentrations is shown in the figure. Detailed Implementation

[0036] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0037] As mentioned above, the present invention provides a compound with temperature resistance and calcium and magnesium resistance, characterized in that the compound has the chemical structure shown in Formula 1:

[0038]

[0039] R1 and R1' are each independently selected from C8-C18 alkyl groups;

[0040] R2, R2', R3 and R3' are each independently selected from C1-C4 alkyl groups;

[0041] c, a', b, b', c, and c' are each independently selected from integers from 1 to 6;

[0042] d is an integer selected from 1 to 10;

[0043] M and M' are each independently selected from H or alkali metal elements;

[0044] X is selected from halogens.

[0045] In some embodiments of the present invention, preferably, R1 and R1' are each independently selected from C8-C16 alkyl groups.

[0046] In some embodiments of the present invention, preferably, R2, R2', R3 and R3' are each independently selected from methyl, ethyl, n-propyl or n-butyl.

[0047] In some embodiments of the present invention, preferably, a, a', b, b', c, and c' are each independently selected from integers from 1 to 4.

[0048] In some embodiments of the present invention, preferably, d is selected from 1, 3, 5, 7 or 9.

[0049] In some embodiments of the present invention, preferably, M and M' are each independently selected from H, Li, Na or K.

[0050] In some embodiments of the present invention, preferably, X is selected from Cl, Br or I.

[0051] In some embodiments of the present invention, preferably, R1 and R1' are each independently selected from C10-C14 straight-chain alkyl groups.

[0052] In some embodiments of the present invention, preferably, R2, R2', R3 and R3' are each independently selected from methyl, ethyl or n-propyl.

[0053] In some embodiments of the present invention, preferably, a, a', b, b', c, and c' are each independently selected from integers from 1 to 3.

[0054] In some embodiments of the present invention, preferably, d is selected from 3 or 5.

[0055] In some embodiments of the present invention, preferably, M and M' are each independently H or Na.

[0056] In some embodiments of the present invention, preferably, X is selected from Cl or Br.

[0057] In some embodiments of the present invention, preferably, the compound represented by Formula 1 has any of the following chemical structures:

[0058]

[0059]

[0060] A second aspect of this invention provides a method for preparing a compound with temperature resistance and calcium and magnesium resistance, characterized in that the method comprises:

[0061] (1) At least one of the compounds A shown in formula A1 is subjected to a quaternization reaction with at least one of the compounds B shown in formula B1;

[0062] (2) The product obtained from the quaternization reaction in step (1) is coupled with compound C to obtain the compound shown in formula 1.

[0063]

[0064]

[0065] Wherein, the compounds represented by Formula 1, R1, R2, R3, a, b, c, d, M, and X correspond to the same definitions as described in the first aspect of the present invention. It is understood that R1, R2, R3, a, b, c, d, and M correspond to R1', R2', R3', a', b', c', d', and M', respectively. When the correspondences are the same (i.e., R1 and R1' are the same, R2 and R2' are the same, and so on), one of the compounds A represented by Formula A1 is subjected to a quaternization reaction with one of the compounds B represented by Formula B1. When the correspondences are different (i.e., R1 and R1' are different, R2 and R2' are different, and so on), at least two of the compounds A represented by Formula A1 are subjected to a quaternization reaction with at least two of the compounds B represented by Formula B1. In another embodiment, compound A represented by formula A1 may further include the compound represented by formula A1', and compound B represented by formula B1 may further include the compound represented by formula B1', so as to obtain compounds (formula 1) that correspond to R1, R2, R3, a, b, c, d, and M respectively with R1', R2', R3', a', b', c', d', and M' respectively:

[0066]

[0067] In some embodiments of the present invention, preferably, the quaternization reaction is carried out in the presence of solvent I and catalyst I.

[0068] In some embodiments of the present invention, preferably, the solvent I is selected from at least one of ethanol, water, isopropanol, N-methylpyrrolidone, and ethylene glycol dimethyl ether.

[0069] In some embodiments of the present invention, preferably, the catalyst I is selected from alkaline substances, more preferably inorganic bases, and even more preferably at least one of NaOH, KOH, Na2CO3 and K2CO3.

[0070] In some embodiments of the present invention, preferably, in step (2), the coupling reaction is carried out in the presence of solvent II, catalyst II and phase transfer catalyst.

[0071] In some embodiments of the present invention, preferably, the solvent II is selected from at least one of ethylene glycol dimethyl ether, isopropanol, N-methylpyrrolidone, and acetone.

[0072] In some embodiments of the present invention, preferably, the catalyst II is selected from alkaline substances, more preferably inorganic bases, and even more preferably at least one of NaOH, KOH, Na2CO3 and K2CO3.

[0073] In some embodiments of the present invention, preferably, the phase transfer catalyst is selected from quaternary ammonium salt catalysts or onium salt catalysts, more preferably at least one of tetrabutylammonium bromide, tetrabutylammonium chloride, benzyltriethylammonium bromide and benzyltriethylammonium chloride.

[0074] In some embodiments of the present invention, preferably, in step (1), the mass ratio of compound A to compound B is 1:1.05-1.2, more preferably 1:1.06-1.18.

[0075] In some embodiments of the present invention, preferably, in step (1), the mass ratio of catalyst I to compound A is 1:4-8, more preferably 1:5-6.

[0076] In some embodiments of the present invention, preferably, the mass ratio of compound A to solvent I is 1:3-10, more preferably 1:4-8.

[0077] In some embodiments of the present invention, preferably, in step (2), the mass ratio of catalyst II to compound A is 1:1.4-2.2, more preferably 1:1.5-2.

[0078] In some embodiments of the present invention, preferably, the mass ratio of compound A to solvent II is 1:3-10, more preferably 1:5-8.

[0079] In some embodiments of the present invention, preferably, the mass ratio of the phase transfer catalyst to compound A is 1:20-70, more preferably 1:30-60.

[0080] In some embodiments of the present invention, preferably, in step (1), the temperature of the quaternization reaction is 65-90°C, more preferably 70-80°C.

[0081] In some embodiments of the present invention, preferably, the quaternization reaction time is 6-16 hours, more preferably 8-12 hours.

[0082] In some embodiments of the present invention, preferably, in step (2), the temperature of the coupling reaction is 65-100°C, more preferably 80-90°C.

[0083] In some embodiments of the present invention, preferably, the coupling reaction time is 12-36 hours, more preferably 18-30 hours.

[0084] A third aspect of the present invention provides the application of the compound described in the first aspect of the present invention in improving the wash oil yield.

[0085] In this invention, compound A, represented by formula A1, can be obtained by an amidation reaction of alkoxybenzoyl chloride and an amine compound, for example, by contacting 4-dodecyloxybenzoyl chloride and N'N-dimethylaminopropylamine and undergoing an amidation reaction to obtain compound A, represented by formula A1.

[0086] In some embodiments of the present invention, preferably, the mass ratio of 4-dodecyloxybenzoyl chloride to N'N-dimethylaminopropylamine is 1-6:1, more preferably 2-4:1.

[0087] In some embodiments of the present invention, preferably, the amidation reaction is carried out in the presence of catalyst III and solvent III.

[0088] In some embodiments of the present invention, preferably, the catalyst III is a 10% by mass NaOH solution and / or a 10% by mass KOH solution.

[0089] In some embodiments of the present invention, preferably, solvent III is at least one of N-methylpyrrolidone, isopropanol, and ethylene glycol dimethyl ether.

[0090] In some embodiments of the present invention, preferably, the mass ratio of 4-dodecyloxybenzoyl chloride to solvent III is 1:2-10, more preferably 1:3-6.

[0091] In some embodiments of the present invention, preferably, the mass ratio of catalyst III to 4-dodecyloxybenzoyl chloride is 1:0.5-5, more preferably 1:1-3.

[0092] In some embodiments of the present invention, preferably, the temperature of the amidation reaction is 90-120°C, more preferably 100-110°C.

[0093] In some embodiments of the present invention, preferably, the amidation reaction takes 3-8 hours, more preferably 4-6 hours.

[0094] The present invention will be described in detail below through examples. In the following examples, the surface tension parameters were measured by the ring method; 4-dodecyloxybenzoyl chloride was a commercially available product of Hubei Dechao Chemical Co., Ltd. with brand name 50909-50-7; p-octyloxybenzoyl chloride was a commercially available product of Shanghai Beierda Pharmaceutical Co., Ltd. with brand name 40782-53-4; N'N-dimethylaminopropylamine was a commercially available product of Shanghai Puzhen Biotechnology Co., Ltd. with brand name 598-56-1; sodium 3-chloro-2-hydroxypropanesulfonate was a commercially available product of Hubei Xinhongli Chemical Co., Ltd. with brand name 126-83-0; 1,3-dibromopropane was a commercially available product of Shanghai Puzhen Biotechnology Co., Ltd. with brand name 109-64-8; and 1,5-dibromopentane was a commercially available product of Shanghai Puzhen Biotechnology Co., Ltd. with brand name 111-24-0.

[0095] Example 1

[0096] (1) Dissolve 19.5 g of 4-dodecyloxybenzoyl chloride in 60 mL of N-methylpyrrolidone at room temperature. In a 250 mL three-necked flask equipped with a magnetic stirrer and a reflux condenser, add 6.13 g of N'N-dimethylaminopropylamine, 10 mL of 10% NaOH solution, and 30 mL of N-methylpyrrolidone. After stirring to dissolve, slowly add the N-methylpyrrolidone solution of 4-dodecyloxybenzoyl chloride dropwise over 15 min. Heat the mixture to 105 °C in an oil bath and react for 5 h. After the reaction is complete, add cold water and stir to promote product precipitation. Cool to room temperature and filter under reduced pressure. Wash the filter cake several times with cold water and dry at 60-70 °C for 24 h to obtain intermediate K (NMR results are shown in the figure). Figure 1 As shown, its structure is as shown in Equation 1-1A.

[0097]

[0098] (2) 19.52 g of intermediate K was added to a 250 mL dry three-necked flask equipped with a condenser, magnetic stir bar, and constant pressure dropping funnel. 80 mL of a mixed solution of ethanol and water (volume ratio 1:1) was added, followed by 3 mL of 50% NaOH solution. The pH of the solution was adjusted to 8.5, and the temperature was raised to 75 °C. 13.72 g of sodium 3-chloro-2-hydroxypropanesulfonate was added, and the reaction was allowed to proceed for 10 h to obtain the crude product. The solvent was removed by vacuum distillation, and the product was separated using petroleum ether and water to remove unreacted sodium 3-chloro-2-hydroxypropanesulfonate. The petroleum ether was removed by vacuum distillation, and the product was dried to obtain the reaction intermediate L used in the preparation of this invention (NMR detection results are as shown in the figure). Figure 2 As shown in the figure, its structure is as shown in Equation 1-1B;

[0099]

[0100] (3) The intermediate L is coupled with compound C in the following process:

[0101] 22.1 g of intermediate L was added to a 250 mL dry three-necked flask equipped with a condenser, magnetic stir bar, and dropping funnel. 80 mL of ethylene glycol dimethyl ether was added, and magnetic stirring was started. After intermediate L was completely dissolved, 10 mL of 50% NaOH solution and 0.5 g of the phase transfer catalyst tetrabutylammonium bromide were added. Then, 10 g of 1,3-dibromopropane was slowly added using a constant-pressure dropping funnel. The mixture was then heated to 85 °C and refluxed for 24 h. After the reaction was complete, the solvent ethylene glycol dimethyl ether and unreacted 1,3-dibromopropane were removed by vacuum distillation. The inorganic salt was then removed with ethanol, followed by ethanol evaporation. The resulting product was recrystallized three times with acetone and dried for 24 h to obtain a white product, which is the prepared compound. Its NMR results are shown below. Figure 3 As shown, the chemical structure is as shown in Formula 1-1.

[0102] Example 2

[0103] (1) Dissolve 19.5 g of 4-dodecyloxybenzoyl chloride in 60 mL of N-methylpyrrolidone at room temperature. In a 250 mL three-necked flask equipped with a magnetic stirrer and a reflux condenser, add 6.13 g of N'N-dimethylpropylamine, 10 mL of 10% NaOH solution, and 30 mL of N-methylpyrrolidone. After stirring to dissolve, slowly add the N-methylpyrrolidone solution of 4-dodecyloxybenzoyl chloride dropwise over 15 min. Heat the mixture to 105 °C in an oil bath and react for 5 h. After the reaction is complete, add cold water and stir to promote product precipitation. Cool to room temperature and filter under reduced pressure. Wash the filter cake several times with cold water and dry at 60-70 °C for 24 h to obtain intermediate K (NMR results are shown in the figure). Figure 1 As shown, its structure is as shown in Equation 1-1A.

[0104] (2) 19.52 g of intermediate K was added to a 250 mL dry three-necked flask equipped with a condenser, magnetic stir bar, and constant pressure dropping funnel. 80 mL of a mixed solution of ethanol and water (volume ratio 1:1) was added, followed by 3 mL of 50% NaOH solution. The pH of the solution was adjusted to 8.5, and the temperature was raised to 75 °C. 13.72 g of sodium 3-chloro-2-hydroxypropanesulfonate was added, and the reaction was allowed to proceed for 10 h to obtain the crude product. The solvent was removed by vacuum distillation, and the product was separated using petroleum ether and water to remove unreacted sodium 3-chloro-2-hydroxypropanesulfonate. The petroleum ether was removed by vacuum distillation, and the product was dried to obtain the reaction intermediate L used in the preparation of this invention (NMR detection results are as shown in the figure). Figure 2 As shown in the figure, its structure is as shown in Equation 1-1B;

[0105] (3) The intermediate L is coupled with compound C in the following process:

[0106] 22.1 g of intermediate L was added to a 250 mL dry three-necked flask equipped with a condenser, magnetic stir bar, and dropping funnel. 80 mL of ethylene glycol dimethyl ether was added, and magnetic stirring was started. After intermediate L was completely dissolved, 10 mL of 50% NaOH solution and 0.5 g of the phase transfer catalyst tetrabutylammonium bromide were added. Then, 11.5 g of 1,5-dibromopentane was slowly added using a constant-pressure dropping funnel. The mixture was then heated to 85 °C and refluxed for 24 h. After the reaction was complete, the solvent ethylene glycol dimethyl ether and unreacted 1,5-dibromopentane were removed by vacuum distillation. The inorganic salt was then removed with ethanol, followed by ethanol evaporation. The resulting product was recrystallized three times with acetone and dried for 24 h to obtain a white product, which is the prepared compound. Its NMR results are shown below. Figure 4 As shown, the chemical structure is as shown in Formula 1-2.

[0107] Example 3

[0108] The compound was synthesized according to the method of Example 1, except that N,N-dimethylethylenediamine was used instead of N,N-dimethyl-1,3-diaminopropane to obtain the compound. The NMR detection results are as follows. Figure 5 As shown, the chemical structure is as shown in Formula 1-3.

[0109]

[0110] Example 4

[0111] The compound was synthesized according to the method of Example 1, except that p-octyloxybenzoyl chloride was used instead of 4-dodecyloxybenzoyl chloride to obtain the compound. The NMR detection results are as follows. Figure 6 As shown, the chemical structure is as shown in Formula 1-4.

[0112]

[0113] Comparative Example 1

[0114] The compound was synthesized according to the method of Example 1, except that isostearyl chloride was used instead of 4-dodecyloxybenzoyl chloride to obtain the compound. The NMR detection results are as follows. Figure 7 As shown, the chemical structure is as shown in Formula 1-5.

[0115]

[0116] Test Example 1

[0117] Five compounds synthesized in Examples 1-4 and Comparative Example 1 were analyzed using a thermogravimetric analyzer. The mass of each compound sample was controlled at 6.58 mg. The compounds were heated from room temperature to 700 °C at a heating rate of 10 °C / min under N2 atmosphere. Thermogravimetric analysis was performed on the heat-resistant and calcium-magnesium-resistant compounds to obtain TG and DTG curves.

[0118] from Figure 8 As can be seen, the compound synthesized in Example 1 experienced only a small amount of weight loss before 250°C, presumably due to some adsorbed water and volatiles. The 250-350°C range was the main weight loss stage, with a weight loss of 33%, representing the decomposition of the main active ingredient, the temperature-resistant calcium-magnesium compound. The weight loss was less (1.5%) and slower between 350-650°C, corresponding to the weight loss of pyrolytic carbon (a decomposition product of the temperature-resistant calcium-magnesium compound). The residual mass was 46%, corresponding to the non-decomposing and non-oxidizing components. From the above analysis results, it can be concluded that the temperature resistance limit of the temperature-resistant calcium-magnesium compound in the sample can reach over 300°C. Other examples also showed similar thermogravimetric effects. The thermogravimetric analysis results of the compounds prepared in Examples 1-4 and Comparative Example 1 are shown in Table 1.

[0119] Table 1

[0120]

[0121]

[0122] Test Example 2

[0123] Surface tension was determined according to the ring method in the People's Republic of China Petroleum and Natural Gas Industry Standard SY / T 5370—2018. The surface tension results of an aqueous solution of the compound described in Example 1 (0.8 wt%) at different temperatures are shown in the figure. Figure 9Under the conditions of produced water in a certain block of the Jianghan Oilfield (mineralization 28000 mg / L, calcium and magnesium concentration 3200 mg / L), BS-12, LHSB, HSB1214, and HSB1618 were selected as reference standards, and the surface tension of the solution was measured under the same concentration conditions (0.8 wt%). Figure 9 As shown, the aqueous solution of the compound described in Example 1 (0.8 wt%) maintained good surface activity in the temperature range of 40°C to 80°C, and its surface tension was consistently lower than that of the other four comparative examples. The surface tension of the solution decreased with increasing temperature, reaching a minimum value of 27.0 mN / m at 75°C. Other examples also exhibited similar surface activity. The surface tension analysis results of the compounds prepared in Examples 1-4, Comparative Example 1, and the control are shown in Table 2.

[0124] Table 2

[0125]

[0126]

[0127] Test Example 3

[0128] An oil displacement experiment was designed to investigate the oil displacement efficiency of temperature-resistant and calcium-magnesium-resistant gemini surfactants. The specific steps are as follows:

[0129] 1. Preparation of oil sand

[0130] Simulated oil treatment was carried out using 200-mesh quartz sand that had been washed and dried with ultrapure water. The oil sand was prepared with a mass ratio of sand to crude oil of 5:1. It was placed in a square container and stirred for 30 minutes to ensure uniform mixing. Then it was placed in an oven and aged at 75°C for 7 days. The oil content of the oil sand was 16.67%. The oil sand was placed in ultrapure water and centrifuged for 30 minutes. The washing liquid remained clear, which proved that the oil sand had a solid structure. Therefore, subsequent oil washing experiments were carried out.

[0131] 2. Formulation of surfactants

[0132] Aqueous solutions of temperature-resistant and calcium- and magnesium-resistant gemini surfactants (i.e., the compounds prepared in the examples and comparative examples) with different mass concentration gradients were prepared using produced water from a block in the Jianghan Oilfield (mineralization 28000 mg / L, calcium and magnesium concentration 3200 mg / L).

[0133] 3. Oil washing operation

[0134] 20g of simulated oil sand was mixed with 80g of the compound solution, and the mixture was aged at 75°C for 2 days, with periodic 2-minute shaking during the aging process. After the above operation was completed, the mixture of the washed simulated oil sand and the washing solution was placed in a constant temperature oven for drying, and the washing efficiency was calculated. The washing efficiency reflects the surfactant's ability to remove oil from the surface of the oil sand. The amount of oil washed is calculated by the difference in mass of the oil sand before and after washing; the higher the value, the higher the washing efficiency. The calculation formula is as follows:

[0135]

[0136] In the formula:

[0137] η represents the oil sand washing rate (%);

[0138] m1 and m2 represent the mass of oil sand before washing and the mass of dry oil sand after washing (g);

[0139] p and q represent the oil content and water content (%) of the oil sands before washing.

[0140] The oil-washing efficiency of the compound prepared in Example 1 was determined according to the above method. The compound was prepared into aqueous solutions with concentrations of 0.2 wt%, 0.4 wt%, 0.6 wt%, 0.8 wt%, and 1 wt%, respectively. A blank experiment without any added components was also set up as a control. Figure 10 As shown, the oil washing efficiency increased with increasing concentration of the compound synthesized in Example 1, reaching a maximum of 35.74% at a concentration of approximately 0.8 wt%. While the oil washing efficiency decreased slightly with increasing cycle count, it remained at a high level. At a concentration of 0.8 wt%, the decrease in oil washing efficiency after multiple washes was less significant compared to concentrations of 0.2 wt%, 0.4 wt%, and 0.6 wt%. Furthermore, the difference in oil washing efficiency at a concentration of 0.8 wt% was not significant compared to 1 wt%. Considering both economic efficiency and applicability, 0.8 wt% was the optimal concentration. Moreover, at concentrations greater than 0.2 wt%, an oil washing efficiency of over 20% was still achieved after three washes, indicating that the compound synthesized in Example 1 possessed strong anti-adsorption capabilities. Other examples also exhibited similar oil washing efficiencies. The oil washing efficiency test results for the compounds prepared in Examples 1-4, Comparative Example 1, and the control are shown in Table 3.

[0141] Table 3

[0142]

[0143]

[0144] As can be seen from the results in Tables 1-3, compared with the comparative examples and control examples, Examples 1-4 using the technical solution of the present invention have significantly better effects in terms of thermal weight loss, surface activity and oil washing efficiency.

[0145] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A compound with temperature resistance and calcium / magnesium resistance, characterized in that, The compound has the chemical structure shown in Formula 1: R1 and R1' are each independently selected from C8-C18 alkyl groups; R2, R2', R3 and R3' are each independently selected from C1-C4 alkyl groups; a, a', b, b', c, and c' are each independently selected from integers from 1 to 6; d is an integer selected from 1 to 10; M and M' are each independently selected from H or alkali metal elements; X is selected from halogens.

2. The compound according to claim 1, wherein, R1 and R1' are each independently selected from C8-C16 alkyl groups; And / or, R2, R2', R3 and R3' are each independently selected from methyl, ethyl, n-propyl or n-butyl; And / or, a, a', b, b', c, and c' are each independently selected from integers from 1 to 4; And / or, d is selected from 1, 3, 5, 7 or 9; And / or, M and M' are each independently selected from H, Li, Na or K; And / or, X is selected from Cl, Br or I.

3. The compound according to claim 2, wherein, R1 and R1' are each independently selected from C10-C14 straight-chain alkyl groups; And / or, R2, R2', R3 and R3' are each independently selected from methyl, ethyl or n-propyl; And / or, a, a', b, b', c, and c' are each independently selected from integers from 1 to 3; And / or, d is selected from 3 or 5; And / or, M and M' are each independently H or Na; And / or, X is selected from Cl or Br.

4. The compound according to claim 3, wherein, The compound shown in Formula 1 has any of the following chemical structures:

5. A method for preparing a compound with temperature resistance and calcium / magnesium resistance, characterized in that, The method includes: (1) At least one of the compounds A shown in formula A1 is subjected to a quaternization reaction with at least one of the compounds B shown in formula B1; (2) The product obtained from the quaternization reaction in step (1) is coupled with compound C to obtain the compound shown in formula 1. Wherein, the compounds shown in Formula 1, R1, R2, R3, a, b, c, d, M, and X correspond to the definitions in any one of claims 1-4.

6. The method according to claim 5, wherein, In step (1), the quaternization reaction is carried out in the presence of solvent I and catalyst I; Preferably, solvent I is selected from at least one of ethanol, water, isopropanol, N-methylpyrrolidone, and ethylene glycol dimethyl ether; Preferably, the catalyst I is selected from alkaline substances, more preferably inorganic bases, and even more preferably at least one of NaOH, KOH, Na2CO3 and K2CO3.

7. The method according to claim 5 or 6, wherein, In step (2), the coupling reaction is carried out in the presence of solvent II, catalyst II and phase transfer catalyst; Preferably, solvent II is selected from at least one of ethylene glycol dimethyl ether, isopropanol, N-methylpyrrolidone, and acetone; Preferably, the catalyst II is selected from alkaline substances, more preferably inorganic bases, and even more preferably at least one of NaOH, KOH, Na2CO3 and K2CO3; Preferably, the phase transfer catalyst is selected from quaternary ammonium salt catalysts or onium salt catalysts, and more preferably at least one of tetrabutylammonium bromide, tetrabutylammonium chloride, benzyltriethylammonium bromide and benzyltriethylammonium chloride.

8. The method according to any one of claims 5-7, wherein, In step (1), the mass ratio of compound A to compound B is 1:1.05-1.2, preferably 1:1.06-1.

18.

9. The method according to any one of claims 6-8, wherein, In step (1), the mass ratio of catalyst I to compound A is 1:4-8, preferably 1:5-6; Preferably, the mass ratio of compound A to solvent I is 1:3-10, more preferably 1:4-8.

10. The method according to any one of claims 7-9, wherein, In step (2), the mass ratio of catalyst II to compound A is 1:1.4-2.2, preferably 1:1.5-2; Preferably, the mass ratio of compound A to solvent II is 1:3-10, more preferably 1:5-8; Preferably, the mass ratio of the phase transfer catalyst to compound A is 1:20-70, and more preferably 1:30-60.

11. The method according to any one of claims 5-10, wherein, In step (1), the temperature of the quaternization reaction is 65-90℃, preferably 70-80℃; Preferably, the quaternization reaction takes 6-16 hours, and more preferably 8-12 hours.

12. The method according to any one of claims 5-11, wherein, In step (2), the temperature of the coupling reaction is 65-100℃, preferably 80-90℃; Preferably, the coupling reaction takes 12-36 hours, and more preferably 18-30 hours.

13. The use of the compound according to any one of claims 1-4 in improving wash oil yield.

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