Wet type clay stabilizer and preparation method thereof

Abstract

The invention belongs to the technical field of oil field clay anti-swelling, and provides a preparation method of a clay stabilizer with a molecular structure simultaneously containing a cationic inhibiting group and a hydrophilic group, and the preparation method is characterized in that hydroxy acid reacts with 3-chloro-2-hydroxypropyltrimethyl ammonium chloride in a solvent under the action of a basifier, and then reacts with sorbitol to prepare the clay stabilizer, and the anti-swelling agent has a good anti-swelling effect and outstanding hydrophilic performance. The anti-swelling rate of the clay stabilizer at room temperature is greater than 80%, the contact angle between treated clay particles and water is kept below 40 degrees, and the clay stabilizer can be used for inhibiting hydration swelling of stratum clay minerals and protecting pore hydrophilicity in the water injection process of an oil well.

Description

Technical Field

[0001] The invention relates to a preparation method of a wet clay stabilizer and belongs to the technical field of oil field additives. Background Art

[0002] Clay minerals mainly include kaolinite, illite, montmorillonite, chlorite, etc., which are common mineral components in strata.

[0003] Montmorillonite is a representative of highly water-sensitive clay minerals. Experiments show that the permeability of a core with a clay mineral content of about 20% is only about 3% of the initial permeability after water invasion. Therefore, a certain concentration of clay stabilizer is often added during conventional water injection or fracturing in oil fields to inhibit the hydration, expansion and dispersion of water-sensitive clay minerals in the formation, thereby protecting the formation permeability.

[0004] Early clay stabilizers were mainly inorganic salts such as potassium chloride, ammonium chloride, and potassium formate. Due to the impact of high concentrations of salts on benthic organisms, they have been gradually replaced by inorganic multi-core polymers, cationic surfactants, and cationic organic polymers. The molecular structure of such clay stabilizers often contains -NH2, -NH3 + 、-N + Adsorption sites such as R4 can adsorb with electronegative clay particles to inhibit the hydration and expansion process of clay particles. Long-term practice has shown that the molecular structure of terminal cationic clay stabilizers such as benzyltrimethylammonium chloride often contains hydrophobic groups such as benzyl rings and hydrocarbon groups. When such hydrophobic clay stabilizers are used in large quantities, they are easily enriched and adsorbed on the surface of formation pores, reducing the hydrophilicity of formation pores, making it impossible for the injected water containing oil displacement agent to enter the formation pores, resulting in a decrease in the water injection and recovery effect of oil wells. Therefore, in the design and synthesis of new clay stabilizers, not only the anti-swelling performance of clay stabilizers should be considered, but also the new problems that will be caused by their enrichment in the formation should be considered. Summary of the invention

[0005] The purpose of the present invention is to solve the above problems and to propose a wetting type clay stabilizer and a preparation method thereof.

[0006] The present invention provides a wetting type clay stabilizer, whose molecular structure has the following characteristics:

[0007] Formula (1) Where R is C6H 13 O6; or

[0008] Formula (2) Where R1 and R2 are C6H 13 O6 or K+ 、Na + One of the following, and R1 and R2 are not K at the same time + Or Na + ; R3 and R4 are C6H 15 ClNO or H, and R3 and R4 are not H at the same time; or

[0009] Formula (3) Where R1 and R2 are C6H 13 O6 or K + 、Na + One of the following, and R1 and R2 are not K at the same time + Or Na + ; or

[0010] Formula (4) Where R1, R2, and R3 are C6H 13 O6 or K + 、Na + One of the following, and R1, R2, and R3 are not K at the same time + Or Na + .

[0011] In the present invention, the molecular formula of sorbitol is C6H 14 O6, whose structural formula is shown in formula (5), contains 6 hydroxyl groups in its molecule. 13 O6 is the remaining group after removing one hydroxyl hydrogen from sorbitol. Since the six hydroxyl groups in the sorbitol molecule are all active in esterification reaction, the C6H 13 O6 can be the dehydrogenation product of any hydroxyl group of sorbitol.

[0012]

[0013] Formula (5).

[0014] In the present invention, the C6H 15 The structure of ClNO is shown in formula (6), where * indicates that the group is connected to a substituent.

[0015]

[0016] Formula (6).

[0017] The present invention also provides a method for preparing a wetting clay stabilizer, which is characterized in that hydroxy acid is etherified by cation and the product is further esterified with polyhydroxy sorbitol to synthesize a wetting clay stabilizer with good anti-swelling effect and strong hydrophilicity.

[0018] Furthermore, the method for preparing a clay stabilizer according to the present invention comprises the following steps: (1) dissolving a hydroxy acid in a solvent and adding an alkalizing agent to react; (2) adding 3-chloro-2-hydroxypropyltrimethylammonium chloride into the above system to react; (3) The product of step (2) is cooled, acid-neutralized, and then impurities are removed by vacuum distillation to obtain an intermediate product; (4) The sorbitol and the intermediate product are reacted in the presence of an acid catalyst, and the product is neutralized, filtered, and subjected to reduced pressure distillation to remove impurities, thereby finally obtaining a clay stabilizer.

[0019] Furthermore, the hydroxy acid described in the present invention can be one of lactic acid, tartaric acid, malic acid and citric acid.

[0020] Furthermore, the solvent of the present invention may be one of water and N,N-dimethylformamide.

[0021] Furthermore, the alkalizing agent described in the present invention can be one of NaOH and KOH.

[0022] Furthermore, the ratio of the amount of the hydroxy acid to the amount of the alkalizing agent in the present invention is 1:2.0-5.0.

[0023] Furthermore, the molar ratio of the hydroxy acid of the present invention to 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:1.0-2.5.

[0024] Furthermore, the reaction temperature of step (2) of the present invention is in the range of 70-110°C.

[0025] Furthermore, the molar ratio of the hydroxy acid to sorbitol in the present invention is 1:1.2-3.5.

[0026] The effects of the present invention are: The hydroxy acid containing hydrophilic groups such as hydroxyl and carboxyl in the molecular structure is cationic etherified, and the intermediate product is further esterified with polyhydroxy sorbitol to obtain a clay stabilizer, which contains both cationic inhibition groups and hydrophilic groups in the molecule. The clay stabilizer can better retain the hydrophilicity of clay particles while inhibiting the hydration expansion of clay, which has a very positive significance for protecting the permeability of the formation and improving the effect of water injection and production of oil wells. Implementation

[0027] The present invention is described in detail below with reference to the embodiments. Example 1

[0028] Weigh 0.1 mol of malic acid into a flask and add 50g of water to it. After the malic acid is completely dissolved under stirring, add 0.4 mol of NaOH and react at 20°C for 1 hour; then add 0.12 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 85°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.2 mol of sorbitol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, the clay stabilizer is finally obtained. Example 2

[0029] Weigh 0.1 mol of malic acid into a flask and add 50 g of water to it. After the malic acid is completely dissolved under stirring, add 0.3 mol of NaOH and react at 20°C for 1 hour; then add 0.2 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 110°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.2 mol of sorbitol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, a clay stabilizer is finally obtained. Example 3

[0030] Weigh 0.1 mol of malic acid into a flask and add 50 g of N,N-dimethylformamide to it. After the malic acid is completely dissolved under stirring, add 0.4 mol of NaOH and react at 20°C for 1 hour; then add 0.1 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 70°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.2 mol of sorbitol to the flask and heat it to 105°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, the clay stabilizer is finally obtained. Example 4

[0031] Weigh 0.1 mol of tartaric acid into a flask and add 50 g of water to it. After the tartaric acid is completely dissolved, add 0.4 mol of NaOH and react at 20°C for 1 hour. Then add 0.25 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 90°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.2 mol of sorbitol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, a clay stabilizer is finally obtained. Example 5

[0032] Weigh 0.1mol of tartaric acid into a flask and add 50g of water to it. After the lactic acid is completely dissolved under stirring, add 0.5mol of NaOH and react at 20℃ for 1 hour; then add 0.1mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 90℃ to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.12mol of sorbitol to the flask and heat it to 95℃ and stir it thoroughly. After mixing evenly, drop 5mL of concentrated sulfuric acid and continue the reaction for 6h. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, the clay stabilizer is finally obtained. Example 6

[0033] Weigh 0.1 mol of lactic acid into a flask and add 50 g of water to it. After stirring until the citric acid is completely dissolved, add 0.2 mol of NaOH and react at 20°C for 1 hour; then add 0.15 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 85°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.12 mol of sorbitol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, a clay stabilizer is finally obtained. Example 7

[0034] Weigh 0.1 mol of citric acid into a flask and add 50 g of water to it. After the citric acid is completely dissolved under stirring, add 0.5 mol of NaOH and react at 20°C for 1 hour; then add 0.15 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 85°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.35 mol of sorbitol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, a clay stabilizer is finally obtained. Example 8

[0035] Weigh 0.1 mol of citric acid into a flask and add 50 g of water to it. After the citric acid is completely dissolved under stirring, add 0.5 mol of KOH and react at 20°C for 1 hour; then add 0.15 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 85°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.12 mol of sorbitol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, the clay stabilizer is finally obtained.

[0036] Comparative Example 1 Weigh 0.1 mol of malic acid into a flask and add 50 g of water thereto. After stirring until the malic acid is completely dissolved, add 0.4 mol of NaOH and react at 20° C. for 1 hour. Then add 0.12 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride into the flask and heat to 85° C. to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutrality, and remove the solvent and excess reactants in the system by reduced pressure distillation to obtain a clay stabilizer.

[0037] Comparative Example 2 Weigh 0.1 mol of tartaric acid into a flask and add 50 g of water to it. After the tartaric acid is completely dissolved, add 0.5 mol of NaOH and react at 20°C for 1 hour. Then add 0.1 mol of 3-chloro-2-hydroxypropyltriethylammonium chloride to the flask and heat it to 90°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.12 mol of sorbitol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, a clay stabilizer is finally obtained.

[0038] Comparative Example 3 Weigh 0.1 mol of malic acid into a flask and add 50 g of water to it. After the citric acid is completely dissolved under stirring, add 0.15 mol of NaOH and react at 20°C for 1 hour; then add 0.15 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 60°C to continue the reaction for 6 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.12 mol of sorbitol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, a clay stabilizer is finally obtained.

[0039] Comparative Example 4 Weigh 0.1 mol of malic acid into a flask and add 50 g of water to it. After the malic acid is completely dissolved under stirring, add 0.4 mol of NaOH and react at 20°C for 1 hour; then add 0.12 mol of 3-chloro-2-hydroxypropyltrimethylammonium chloride to the flask and heat it to 85°C to continue the reaction for 3 hours. After the reaction is completed, add a little hydrochloric acid to adjust the product to neutral, and remove the solvent and excess reactants in the system by vacuum distillation to obtain an intermediate product. Continue to add 0.2 mol of propylene glycol to the flask and heat it to 95°C and stir it thoroughly. After mixing evenly, drop 5 mL of concentrated sulfuric acid and continue the reaction for 6 hours. After the reaction is completed, add a little alkali solution to adjust the product to neutral. After vacuum distillation to remove impurities, a clay stabilizer is finally obtained.

[0040] Test Example 1 The test steps for the anti-swelling performance of clay stabilizer are as follows: The anti-swelling rate test was carried out according to the "SY / T5971-2016 Performance Evaluation Method of Clay Stabilizer for Water Injection", and the steps are as follows: weigh 0.5 g of sodium bentonite, add it to a 10 mL centrifuge tube, add deionized water to the 10 mL mark, shake it thoroughly, let it stand at room temperature for 2 h, put it into a centrifuge, centrifuge it at a speed of 1500 r / min for 15 min, and read the volume V2 of sodium bentonite in water. Use the same steps to replace clean water with a 2wt% clay stabilizer aqueous solution, and measure the volume V1 of the soil after centrifugation. Use kerosene instead of water to measure the volume V0 of the soil.

[0041]

[0042] In the formula: η—anti-swelling rate, %; V0—volume of sodium bentonite in kerosene, mL; V1—volume of sodium bentonite in clay stabilizer, mL; V2—volume of sodium bentonite in clean water, mL.

[0043] Test Example 2 The steps for testing the hydrophilicity of clay particles are as follows: Prepare 1000 mL of 10 wt% aqueous solution of the clay stabilizer to be tested, add 40 g of bentonite and stir thoroughly for more than 24 hours; After step 1 is completed, a suction filtration operation is performed and the bentonite particles obtained by suction filtration are dried in the shade at room temperature; Take 20 g of the bentonite particles obtained by air drying in step (2), and compress them into tablets under a pressure of 10 MPa; The contact angle between deionized water and the pressed tablet obtained in step (3) was measured using a contact angle meter.

[0044] Note: The contact angle between the original soil particles and water is measured directly after the untreated original soil particles are pressed into tablets.

[0045] The samples prepared in Examples 1-8 and Comparative Examples 1-4 were evaluated with reference to the evaluation method in Test Example 1-2. The evaluation results are shown in Table 1.

[0046] Table 1 Clay stabilizer performance evaluation test

[0047] It can be seen from the above examples and comparative examples that the hydrophilicity of the untreated original soil particles with water is good, and the contact angle is only 31.7°. The hydrophilicity of the clay particles treated with a general cationic clay stabilizer such as benzyltrimethylammonium chloride is significantly reduced, and the contact angle with water reaches 104.2°. The hydrophilic clay stabilizer containing a hydrophilic group prepared by the present invention has excellent anti-swelling performance, and the hydrophilic protection effect of the clay particles is obvious. The contact angle is maintained below 40°, and has a good application prospect.

Claims

1. A wetting type clay stabilizer, characterized in that Its molecular structure has the following characteristics: Formula (1) Where R is C6H 13 O6; or Formula (2) Where R1 and R2 are C6H 13 O6 or K + 、Na + One of the following, and R1 and R2 are not K at the same time + Or Na + ; R3 and R4 are C6H 15 ClNO or H, and R3 and R4 are not H at the same time; or Formula (3) Where R1 and R2 are C6H 13 O6 or K + 、Na + One of the following, and R1 and R2 are not K at the same time + Or Na + ; or Formula (4) Where R1, R2, and R3 are C6H 13 O6 or K + 、Na + One of the following, and R1, R2, and R3 are not K at the same time + Or Na + .

2. The wetting type clay stabilizer according to claim 1, characterized in that The C6H 13 O6 is the dehydrogenation product of any hydroxyl group of sorbitol.

3. The wetting type clay stabilizer according to claim 1, characterized in that The C6H 15 The structural formula of ClNO is as follows: Formula (6) Wherein * indicates that the group is connected to a substituent.

4. A method for preparing a wettable clay stabilizer according to any one of claims 1 to 3, characterized in that The hydroxy acid is etherified by cationization and the product is further esterified with polyhydroxy sorbitol to synthesize a wetting clay stabilizer.

5. The method for preparing the wettable clay stabilizer according to claim 4, characterized in that The preparation process includes the following steps: (1) dissolving a hydroxy acid in a solvent and adding an alkalizing agent to react; (2) adding 3-chloro-2-hydroxypropyltrimethylammonium chloride into the above system to react; (3) The product of step (2) is cooled, acid-neutralized, and then impurities are removed by vacuum distillation to obtain an intermediate product; (4) The sorbitol and the intermediate product are reacted in the presence of an acid catalyst, and the product is neutralized, filtered, and subjected to reduced pressure distillation to remove impurities, thereby finally obtaining a clay stabilizer.

6. The method for preparing the wettable clay stabilizer according to claim 5, characterized in that The hydroxy acid is selected from lactic acid, tartaric acid, malic acid and citric acid.

7. The method for preparing the wetting type clay stabilizer according to claim 5, characterized in that The solvent is selected from water and N,N-dimethylformamide.

8. The method for preparing the wettable clay stabilizer according to claim 5, characterized in that The alkalizing agent is selected from one of NaOH and KOH.

9. The method for preparing the wettable clay stabilizer according to claim 5, characterized in that The ratio of the amount of the hydroxy acid to the amount of the alkalizing agent is 1:2.0-5.

0.

10. The method for preparing the wettable clay stabilizer according to claim 5, characterized in that The molar ratio of the hydroxy acid to 3-chloro-2-hydroxypropyltrimethylammonium chloride is 1:1.0-2.

5.

11. The method for preparing a wettable clay stabilizer according to claim 5, wherein the reaction temperature of step (2) is in the range of 70-110°C.

12. The method for preparing the wetting type clay stabilizer according to claim 5, characterized in that The molar ratio of the hydroxy acid to the sorbitol is 1:1.2-3.5.

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