Long-acting temperature-resistant clay stabilizer and preparation method thereof

Abstract

The invention relates to the technical field of oil field clay anti-swelling, and provides a preparation method of a clay stabilizer with multiple adsorption sites in a molecular structure and containing special groups, benzyl chloride reacts with polyamine in an organic solvent system under the action of a base catalyst to prepare the clay stabilizer, and the clay stabilizer has better high-temperature anti-swelling effect and outstanding washing resistance. The anti-swelling rate of the clay stabilizer at room temperature can be up to 91% at most, the anti-swelling rate after aging at 300 DEG C can be up to 88% at most, the washing resistance rate after multiple times of washing is still kept at 100%, the preparation process is simple, and the clay stabilizer can be used for inhibiting hydration swelling of stratum clay minerals in the water injection process of an oil well.

Description

Technical Field

[0001] The invention relates to a long-acting temperature-resistant clay stabilizer and a preparation method thereof, belonging to the technical field of oilfield 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 to electronegative clay particles and inhibit the hydration and expansion process of clay particles.

[0005] Long-term practice has shown that the types of adsorption groups in the molecular structure of this type of clay stabilizer are relatively single. During the long-term water injection and production process, it is easy to desorb under the influence of formation temperature, fluid and other chemicals, and gradually lose the effect of inhibiting clay hydration, expansion and dispersion.

[0006] Therefore, the development of long-lasting temperature-resistant clay stabilizers with multiple types of adsorption sites and specific temperature-resistant groups has become a new research hotspot. Summary of the invention

[0007] The purpose of the present invention is to synthesize a high-efficiency clay stabilizer having multiple adsorption sites in the molecule and a temperature-resistant group in the molecular structure and a preparation method thereof.

[0008] The molecular structure of the main component of the long-acting temperature-resistant clay stabilizer described in the present invention has the following characteristics: Where n=2~4, R is Cl, HCOO, CH3COO, ClCH2COO.

[0009] The method for preparing a long-acting temperature-resistant clay stabilizer according to the present invention is characterized in that the preparation process comprises the following steps: (1) Weigh a certain amount of benzyl chloride and dissolve it in an organic solvent and add a certain amount of water and an alkali catalyst; (2) Weigh a certain amount of polyamine, add it into the above system and react it at a certain temperature for a period of time; (3) After the reaction is completed, the product is cooled, filtered, washed with water, and the aqueous phase product is collected; (4) After the aqueous phase product is neutralized with acid, water is removed by a rotary evaporator to finally obtain a clay stabilizer.

[0010] The invention discloses a method for preparing a long-acting heat-resistant clay stabilizer, characterized in that the reactants are benzyl chloride and a polyamine, wherein the polyamine can be one of N,N-dimethyl-1,2-ethylenediamine, N,N-dimethyl-1,3-propylenediamine and N,N-dimethyl-1,4-butanediamine.

[0011] The method for preparing a long-acting temperature-resistant clay stabilizer of the present invention can use an organic solvent selected from the group consisting of cyclohexane, benzene, toluene and chloroform.

[0012] In the preparation method of the long-acting temperature-resistant clay stabilizer described in the present invention, the base catalyst added in the reaction process can be one of NaOH, KOH and tetramethylguanidine.

[0013] The method for preparing a long-acting temperature-resistant clay stabilizer of the present invention has a reaction temperature range of 50-105°C.

[0014] The method for preparing a long-acting temperature-resistant clay stabilizer disclosed by the present invention has a reaction time of 4 to 16 hours.

[0015] The method for preparing a long-acting temperature-resistant clay stabilizer disclosed by the present invention comprises a molar ratio of reactants benzyl chloride to polyamine of 0.6:1 to 1:0.8.

[0016] In the preparation method of the long-acting temperature-resistant clay stabilizer described in the present invention, the addition amount of the alkali catalyst is 24%-39% of the total mass of benzyl chloride.

[0017] The invention discloses a method for preparing a long-acting temperature-resistant clay stabilizer, wherein the neutralizing acid can be one of hydrochloric acid, formic acid, acetic acid and chloroacetic acid.

[0018] The beneficial effects of the present invention are: The multi-level amine adsorption sites in the clay stabilizer molecule can effectively enhance the adsorption of the clay stabilizer and electronegative clay particles, and enhance the water washability of the clay stabilizer; The benzene ring in the molecular structure of the agent not only improves the temperature resistance of the molecule, but also helps to form a hydrophobic shielding layer, further preventing the hydration, expansion and dispersion of clay particles; The synthesis process adopted by the invention is simple and efficient, and the polyamine and the alkali catalyst which have not reacted completely are still effective components of the clay stabilizer after being washed, neutralized and impurities removed.

[0019] The clay stabilizer provided by the present invention has excellent anti-swelling performance, outstanding heat resistance and water washing resistance, the anti-swelling rate can reach up to 91% at room temperature, the anti-swelling rate can reach up to 88% after aging at 300°C, and the water washing resistance rate is still basically maintained at 100% after multiple water washings; the preparation process is simple, and the clay stabilizer can be used to inhibit the hydration expansion of formation clay minerals during oil well water injection, and has good application prospects. Implementation

[0020] The present invention is described in detail below with reference to the embodiments.

[0021] Example 1 Weigh 100g of chloroform in a 250mL flask and add 5.0g of deionized water, 7.62g of benzyl chloride and 3.0g of NaOH. Continue to add 8.8g of N,N-dimethyl-1,2-ethylenediamine to the flask under stirring and stir at 50°C for 16h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL of deionized water and separated with a separatory funnel to obtain an aqueous phase. A small amount of hydrochloric acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the neutral product containing water is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0022] Example 2 Weigh 100g of cyclohexane into a 250mL flask and add 5.0g of deionized water, 10.16g of benzyl chloride and 3.0g of NaOH. Continue to add 8.8g of N,N-dimethyl-1,2-ethylenediamine to the flask under stirring and stir at 75°C for 8h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL of deionized water and separated with a separatory funnel to obtain the aqueous phase. Add a small amount of hydrochloric acid to the separated aqueous phase product to adjust the pH to about 7. Finally, the neutral product containing water is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0023] Example 3 Weigh 100g toluene into a 250mL flask and add 5.0g deionized water, 10.16g benzyl chloride and 3.0g KOH. Continue to add 8.8g N,N-dimethyl-1,2-ethylenediamine to the flask under stirring and stir at 105°C for 4h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL deionized water and separated with a separatory funnel to obtain the aqueous phase. A small amount of formic acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the neutral product containing water is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0024] Example 4 Weigh 100g toluene in a 250mL flask and add 5.0g deionized water, 12.7g benzyl chloride and 3.0g KOH. Continue to add 8.8g N,N-dimethyl-1,2-ethylenediamine to the flask under stirring and stir at 105°C for 4h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL deionized water and separated with a separatory funnel to obtain the aqueous phase. A small amount of formic acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the water-containing neutral product is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0025] Example 5 Weigh 100g of toluene in a 250mL flask and add 5.0g of deionized water, 12.7g of benzyl chloride and 3.0g of tetramethylguanidine. Continue to add 7.92g of N,N-dimethyl-1,2-ethylenediamine to the flask under stirring and stir at 105°C for 4h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL of deionized water and separated with a separatory funnel to obtain an aqueous phase. A small amount of acetic acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the neutral product containing water is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0026] Example 6 Weigh 100g toluene in a 250mL flask and add 5.0g deionized water, 12.7g benzyl chloride and 3.0g tetramethylguanidine. Continue to add 7.04g N,N-dimethyl-1,2-ethylenediamine to the flask under stirring and stir at 105°C for 4h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL deionized water and separated with a separatory funnel to obtain an aqueous phase. A small amount of chloroacetic acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the water-containing neutral product is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0027] Example 7 Weigh 100g toluene in a 250mL flask and add 5.0g deionized water, 10.16g benzyl chloride and 3.0g KOH. Continue to add 10.2g N,N-dimethyl-1,3-propylenediamine to the flask under stirring and stir at 105°C for 4h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL deionized water and separated with a separatory funnel to obtain an aqueous phase. A small amount of formic acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the neutral product containing water is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0028] Example 8 Weigh 100g toluene in a 250mL flask and add 5.0g deionized water, 10.16g benzyl chloride and 3.0g KOH. Continue to add 11.6g N,N-dimethyl-1,4-butanediamine to the flask under stirring and stir at 105°C for 4h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL deionized water and separated with a separatory funnel to obtain an aqueous phase. A small amount of formic acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the water-containing neutral product is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0029] Example 9 Weigh 100g of benzene in a 250mL flask and add 5.0g of deionized water, 10.16g of benzyl chloride and 3.0g of KOH. Continue to add 11.6g of N,N-dimethyl-1,4-butanediamine to the flask under stirring and stir at 75°C for 8h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 150mL of deionized water and separated with a separatory funnel to obtain an aqueous phase. A small amount of formic acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the water-containing neutral product is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0030] Comparative Example 1 Weigh 100g toluene into a 250mL flask and add 5.0g deionized water, 10.16g benzyl chloride and 3.0g KOH. Continue to add 12.7g N,N-dimethylcyclohexylamine to the flask under stirring and stir at 105°C for 4h. After the reaction is completed, the product is cooled and filtered. The filtrate is fully washed with 300mL deionized water and separated with a separatory funnel to obtain the aqueous phase. A small amount of formic acid is added to the separated aqueous phase product to adjust the pH to about 7. Finally, the neutral product containing water is evaporated and dehydrated in a rotary evaporator to obtain a clay stabilizer.

[0031] Test Example 1 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.

[0032] Formula (1) 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.

[0033] Test Example 2 The anti-swelling rate test steps after aging at 300°C are as follows: (1) Weigh 3.00 g of bentonite powder, accurate to 0.01 g, and load it into a high temperature and high pressure closed reactor; (2) Add 60 mL of 4 wt% clay stabilizer solution, shake well to mix, place in an oven at 300±2℃ for 24 h, and cool to room temperature; (3) Transfer all the clay mixture in the high-temperature and high-pressure closed reactor into a 100 mL beaker, shake it thoroughly, quickly take out 10 mL and add it to a glass centrifuge tube, put it into a centrifuge with automatic balancing function, centrifuge it at 1500 r / min for 15 min, and read the expansion volume V1 of the bentonite. The anti-swelling rate calculation formula is as follows: Formula (2) Where: V0 is the expansion volume of bentonite in kerosene; V1 is the expansion volume of bentonite in clay stabilizer aqueous solution; V2 is the expansion volume of bentonite in clean water; Test Example 3 The steps for testing washability are as follows: Pour out the supernatant in the centrifuge tube after centrifugation in the above Experimental Example 2, add deionized water to 10 mL, stir thoroughly, let stand for 2 h, and then centrifuge at 1500 r / min for 15 min in a centrifuge; After step 1 is completed, pour out the supernatant in the centrifuge tube again and repeat step (1) to finally read the final volume V1 of the bentonite in the centrifuge tube. ′ , recorded as 1 water wash.

[0034] Washability calculation formula: Formula (3) Where: V1 is the expansion volume of bentonite in clay stabilizer aqueous solution, mL; V1 ′ V is the expansion volume of bentonite after washing, mL; V2 is the expansion volume of bentonite in clean water, mL.

[0035] The samples prepared in Examples 1 to 9 and Comparative Example 1 were evaluated with reference to the evaluation methods in Test Examples 1 to 3. The evaluation results are shown in Table 1.

[0036] Table 1 Clay stabilizer performance evaluation test .

[0037] It can be seen from the above examples that the clay stabilizer provided by the present invention has an anti-swelling rate of up to 91% at room temperature, an anti-swelling rate of up to 88% after aging at 300°C, and a water wash resistance rate of 100% after multiple water washings. The preparation process is simple and can be used to inhibit the hydration expansion of formation clay minerals during oil well water injection.

[0038] The clay stabilizer containing multiple adsorption sites and benzene rings prepared by the present invention has excellent anti-swelling performance, outstanding heat resistance and water washing resistance, simple preparation process and good application prospect.

Claims

1. A long-lasting temperature-resistant clay stabilizer, characterized in that The molecular structure of its main components is as follows: Where n=2~4, R is Cl, HCOO, CH3COO, ClCH2COO.

2. A method for preparing the long-lasting heat-resistant clay stabilizer according to claim 1, characterized in that The following steps are involved: (1) dissolving benzyl chloride in an organic solvent and adding water and an alkali catalyst; (2) adding polyamine to the above system for reaction; (3) After the reaction is completed, the product is cooled, filtered, washed with water, and the aqueous phase product is collected; (4) After the aqueous phase product is neutralized with acid, water is removed by a rotary evaporator to finally obtain a clay stabilizer.

3. The method for preparing the long-acting temperature-resistant clay stabilizer according to claim 2, characterized in that The polyamine is one of N,N-dimethyl-1,2-ethylenediamine, N,N-dimethyl-1,3-propylenediamine and N,N-dimethyl-1,4-butanediamine.

4. The method for preparing the long-acting temperature-resistant clay stabilizer according to claim 2, characterized in that The organic solvent is one of cyclohexane, benzene, toluene and chloroform.

5. The method for preparing the long-acting temperature-resistant clay stabilizer according to claim 2, characterized in that The base catalyst is one of NaOH, KOH and tetramethylguanidine.

6. The method for preparing the long-acting temperature-resistant clay stabilizer according to claim 2, characterized in that The reaction temperature is between 50 and 105°C.

7. The method for preparing the long-acting temperature-resistant clay stabilizer according to claim 2, characterized in that The reaction time is 4 to 16 hours.

8. The method for preparing the long-acting temperature-resistant clay stabilizer according to claim 2, characterized in that The molar ratio of the reactants benzyl chloride to the polyamine is 0.6:1~1:0.

8.

9. The method for preparing the long-acting temperature-resistant clay stabilizer according to claim 2, characterized in that The amount of the base catalyst added is 24% to 39% of the mass of the benzyl chloride.

10. The method for preparing the long-acting temperature-resistant clay stabilizer according to claim 2, characterized in that The neutralizing acid is one of hydrochloric acid, formic acid, acetic acid and chloroacetic acid.

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