A clay stabilizer and a method for preparing the same

Abstract

The present application relates to the technical field of oilfield clay anti-swelling, and provides a preparation method of a clay stabilizer with multiple adsorption sites and special groups in molecular structure, which is prepared by the reaction of benzyl chloride with polyamine in an organic solvent system under the action of an alkali catalyst, and has good high-temperature anti-swelling effect and outstanding water washing resistance. The anti-swelling rate of the clay stabilizer can reach 91% at room temperature, the anti-swelling rate can reach 88% after aging at 300 DEG C, and the water washing resistance rate can remain at 100% after multiple water washing, and the preparation process is simple, and the clay stabilizer can be used for inhibiting the hydration and swelling of formation clay minerals in the water injection process of oil wells.

Description

Technical Field

[0001] This invention relates to a long-lasting, temperature-resistant clay stabilizer and its preparation method, belonging to the field of oilfield additives technology. Background Technology

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

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

[0004] Early clay stabilizers were mainly inorganic salts such as potassium chloride, ammonium chloride, and potassium formate. However, due to the negative impact of high concentrations of salts on benthic organisms, they have been gradually replaced by inorganic polynuclear polymers, cationic surfactants, and cationic organic polymers. These clay stabilizers often contain -NH2 and -NH3 groups in their molecular structure. + -N + Adsorption sites such as R4 can adsorb onto electronegative clay particles, inhibiting the hydration and swelling process of clay particles.

[0005] Long-term practice has shown that the adsorption groups in the molecular structure of this type of clay stabilizer are relatively simple. During long-term water injection and mining, it is easy to desorb under the combined influence of formation temperature, fluid and other chemical agents, and gradually lose its function of inhibiting clay hydration, expansion and dispersion.

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

[0007] The purpose of this invention is to synthesize a highly efficient clay stabilizer with multiple adsorption sites in the molecule and a heat-resistant group in the molecular structure, and to prepare the same.

[0008] The long-lasting, temperature-resistant clay stabilizer of this invention has the following characteristics in the molecular structure of its main components: Where n = 2~4, and R is Cl, HCOO, CH3COO, or ClCH2COO.

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

[0010] The present invention discloses a method for preparing a long-lasting, temperature-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-propanediamine, and N,N-dimethyl-1,4-butanediamine.

[0011] The method for preparing a long-lasting, temperature-resistant clay stabilizer according to the present invention uses an organic solvent selected from cyclohexane, benzene, toluene, and chloroform.

[0012] The method for preparing a long-lasting, temperature-resistant clay stabilizer according to the present invention can use an alkaline catalyst added during the reaction process, which can be one of NaOH, KOH, or tetramethylguanidine.

[0013] The preparation method of the long-lasting temperature-resistant clay stabilizer described in this invention has a reaction temperature range of 50~105℃.

[0014] The preparation method of the long-lasting temperature-resistant clay stabilizer described in this invention has a reaction time of 4 to 16 hours.

[0015] The present invention discloses a method for preparing a long-lasting, temperature-resistant clay stabilizer, wherein the molar ratio of the reactant benzyl chloride to polyamine is 0.6:1 to 1:0.8.

[0016] The preparation method of the long-lasting temperature-resistant clay stabilizer of the present invention involves adding an alkaline catalyst at a rate of 24%-39% of the total mass of benzyl chloride.

[0017] The present invention discloses a method for preparing a long-lasting, temperature-resistant clay stabilizer, wherein the acid used for neutralization may be one of hydrochloric acid, formic acid, acetic acid, or chloroacetic acid.

[0018] The beneficial effects of this invention are as follows: The multi-level amine adsorption sites in the clay stabilizer molecule can effectively enhance the adsorption of the clay stabilizer to electronegative clay particles and enhance the water washability of the clay stabilizer. The benzene ring in the molecular structure of this agent not only enhances 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 used in this invention is simple and efficient. The unreacted polyamines and alkaline catalysts remain effective components of the clay stabilizer after being washed, neutralized and purified by water.

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

[0020] The present invention will now be described in detail with reference to the embodiments.

[0021] Example 1 100g of chloroform was weighed into a 250mL flask, and 5.0g of deionized water, 7.62g of benzyl chloride, and 3.0g of NaOH were added. While stirring, 8.8g of N,N-dimethyl-1,2-ethylenediamine was added to the flask, and the mixture was stirred at 50℃ for 16 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of hydrochloric acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0022] Example 2 100g of cyclohexane was weighed into a 250mL flask, and 5.0g of deionized water, 10.16g of benzyl chloride, and 3.0g of NaOH were added. While stirring, 8.8g of N,N-dimethyl-1,2-ethylenediamine was added to the flask, and the mixture was stirred at 75℃ for 8 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of hydrochloric acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0023] Example 3 100g of toluene was weighed into a 250mL flask, and 5.0g of deionized water, 10.16g of benzyl chloride, and 3.0g of KOH were added. While stirring, 8.8g of N,N-dimethyl-1,2-ethylenediamine was added to the flask, and the mixture was stirred at 105℃ for 4 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of formic acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0024] Example 4 100g of toluene was weighed into a 250mL flask, and 5.0g of deionized water, 12.7g of benzyl chloride, and 3.0g of KOH were added. While stirring, 8.8g of N,N-dimethyl-1,2-ethylenediamine was added to the flask, and the mixture was stirred at 105℃ for 4 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of formic acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0025] Example 5 100g of toluene was weighed into a 250mL flask, and 5.0g of deionized water, 12.7g of benzyl chloride, and 3.0g of tetramethylguanidine were added. While stirring, 7.92g of N,N-dimethyl-1,2-ethylenediamine was added to the flask, and the mixture was stirred at 105℃ for 4 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of acetic acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0026] Example 6 100g of toluene was weighed into a 250mL flask, and 5.0g of deionized water, 12.7g of benzyl chloride, and 3.0g of tetramethylguanidine were added. While stirring, 7.04g of N,N-dimethyl-1,2-ethylenediamine was added to the flask, and the mixture was stirred at 105℃ for 4 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of chloroacetic acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0027] Example 7 100g of toluene was weighed into a 250mL flask, and 5.0g of deionized water, 10.16g of benzyl chloride, and 3.0g of KOH were added. While stirring, 10.2g of N,N-dimethyl-1,3-propanediamine was added to the flask, and the mixture was stirred at 105℃ for 4 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of formic acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0028] Example 8 100g of toluene was weighed into a 250mL flask, and 5.0g of deionized water, 10.16g of benzyl chloride, and 3.0g of KOH were added. While stirring, 11.6g of N,N-dimethyl-1,4-butanediamine was added to the flask, and the mixture was stirred at 105℃ for 4 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of formic acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0029] Example 9 100g of benzene was weighed into a 250mL flask, and 5.0g of deionized water, 10.16g of benzyl chloride, and 3.0g of KOH were added. While stirring, 11.6g of N,N-dimethyl-1,4-butanediamine was added to the flask, and the mixture was stirred at 75℃ for 8 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 150mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of formic acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0030] Comparative Example 1 100g of toluene was weighed into a 250mL flask, and 5.0g of deionized water, 10.16g of benzyl chloride, and 3.0g of KOH were added. While stirring, 12.7g of N,N-dimethylcyclohexylamine was added to the flask, and the mixture was stirred at 105℃ for 4 hours. After the reaction was complete and the product cooled, it was filtered. The filtrate was thoroughly washed with 300mL of deionized water and separated into an aqueous phase using a separatory funnel. A small amount of formic acid was added to the separated aqueous phase to adjust the pH to approximately 7. Finally, the aqueous neutral product was evaporated in a rotary evaporator to remove water, ultimately yielding the clay stabilizer.

[0031] Experimental Example 1 The anti-swelling rate test was conducted according to the "Sy / T5971-2016 Performance Evaluation Method of Clay Stabilizer for Water Injection". 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 thoroughly, let stand at room temperature for 2 h, put it into a centrifuge, and centrifuge at 1500 r / min for 15 min. Read the volume V2 of sodium bentonite in water. Use the same procedure but replace water with a 2 wt% clay stabilizer aqueous solution to measure the volume V1 of the soil after centrifugation. Use kerosene instead of water to measure the volume V0 of the soil.

[0032] Equation (1) Where: 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 water, mL.

[0033] Experimental Example 2 The steps for testing the anti-swelling rate after aging at 300℃ are as follows: (1) Weigh 3.00 g of bentonite powder, accurate to 0.01 g, and put it into a high-temperature and high-pressure closed reactor; (2) Add 60 mL of clay stabilizer solution with a concentration of 4wt%, shake well and mix thoroughly, then 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, high-pressure closed reactor into a 100 mL beaker, shake thoroughly, quickly remove 10 mL and add it to a glass centrifuge tube, place it in a centrifuge with an automatic balancing function, centrifuge at 1500 r / min for 15 min, and read the swelling volume V1 of the bentonite. The formula for calculating the anti-swelling rate is as follows: Equation (2) In the formula: V0 is the expansion volume of bentonite in kerosene; V1 is the expansion volume of bentonite in an aqueous solution of clay stabilizer; V2 is the expansion volume of bentonite in water. Experimental Example 3 The test procedure for water wash resistance is as follows: Pour out the supernatant liquid from the centrifuge tube after centrifugation in Example 2 above, 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 from the centrifuge tube again and repeat step (1). Finally, read the final volume V1 of the bentonite in the centrifuge tube. ′ This is recorded as one wash.

[0034] Formula for calculating water wash resistance: Equation (3) In the formula: V1 is the swelling volume of bentonite in the clay stabilizer aqueous solution, mL; V1 ′ V1 represents the volume of bentonite that has expanded after being washed with water, in mL; V2 represents the volume of bentonite that has expanded in water, in mL.

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

[0036] Table 1 Performance Evaluation Tests of Clay Stabilizers .

[0037] As can be seen from the above embodiments, the clay stabilizer provided by the present invention can achieve a maximum anti-swelling rate of 91% at room temperature and a maximum anti-swelling rate of 88% after aging at 300℃. After multiple water washings, the water washing resistance rate is still basically maintained at 100%. The preparation process is simple and can be used to inhibit the hydration and swelling of formation clay minerals during oil well water injection.

[0038] The clay stabilizer prepared by this invention, containing multiple adsorption sites and benzene rings, exhibits excellent anti-swelling properties, outstanding temperature resistance and water washing resistance, and has a simple preparation process, showing promising application prospects.

Claims

1. A clay stabilizer, characterized in that... The molecular structures of its main components are as follows: Where n = 2~4, and R is Cl, HCOO, CH3COO, or ClCH2COO; The preparation method of the long-lasting, temperature-resistant clay stabilizer includes the following steps: (1) Dissolve benzyl chloride in an organic solvent and add water and an alkaline catalyst; the alkaline catalyst is one of NaOH, KOH, and tetramethylguanidine; (2) Add the polyamine to the above system and react; the polyamine is one of N,N-dimethyl-1,2-ethylenediamine, N,N-dimethyl-1,3-propanediamine, and N,N-dimethyl-1,4-butanediamine; (3) After the reaction is complete, the product is cooled, filtered, washed with water, and the aqueous phase product is collected. (4) After the aqueous phase product is neutralized by acid, water is removed by rotary evaporator to finally obtain clay stabilizer; the neutralizing acid is one of hydrochloric acid, formic acid, acetic acid and chloroacetic acid.

2. The clay stabilizer according to claim 1, characterized in that... The organic solvent is one of cyclohexane, benzene, toluene, and chloroform.

3. The clay stabilizer according to claim 1, characterized in that... The reaction temperature is between 50 and 105°C.

4. The clay stabilizer according to claim 1, characterized in that... The reaction time is 4 to 16 hours.

5. The clay stabilizer according to claim 1, characterized in that... The molar ratio of the reactant benzyl chloride to the polyamine is 0.6:1 to 1:0.

8.

6. The clay stabilizer according to claim 1, characterized in that... The amount of the alkaline catalyst added is 24% to 39% of the mass of benzyl chloride.

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