Trihydroxy quaternary ammonium salt micromolecular clay stabilizer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of oil field clay stabilizers, in particular to a trihydroxy quaternary ammonium salt micromolecular clay stabilizer as well as a preparation method and application thereof, and the trihydroxy quaternary ammonium salt micromolecular clay stabilizer can be obtained by reacting methylamine hydrochloride and 2, 3-epoxypropyl trimethyl ammonium chloride serving as reaction raw materials at a certain temperature. The prepared trihydroxy quaternary ammonium salt micromolecular clay stabilizer is a trihydroxy quaternary ammonium salt aqueous solution, the trihydroxy quaternary ammonium salt contains strong polar molecules of four cations and three hydroxyls, the molecular weight is small, the charge density is high, the washing resistance is high, the clay expansion prevention effect is remarkable, and the temperature resistance reaches 207 DEG C; the preparation method is simple, safe and controllable in reaction process and suitable for large-scale production; the molecular weight is small, and secondary damage to the reservoir is avoided.

Description

Technical Field

[0001] This invention relates to the field of oilfield clay stabilizer technology, specifically a trihydroxyquaternary ammonium salt small molecule clay stabilizer and its preparation method. It also includes the application of the trihydroxyquaternary ammonium salt small molecule clay stabilizer in fracturing operations of low-permeability or ultra-low-permeability reservoirs, and is particularly suitable for acid fracturing or water injection in low-permeability or ultra-low-permeability reservoirs. Background Technology

[0002] Clay stabilizers are chemical agents that inhibit the expansion of clay particles and the migration of clay particles in formations. They mainly include cationic polyacrylamide and quaternary ammonium salt clay stabilizers. Quaternary ammonium salt clay stabilizers have the advantages of low dosage, high efficiency, strong adaptability to formations, and effectiveness in both acidic and alkaline environments. Therefore, quaternary ammonium salt clay stabilizers are one of the hot topics in clay stabilizer research and development.

[0003] The anti-swelling mechanism of quaternary ammonium salt clay stabilizers: The positively charged ions on the quaternary ammonium salt polymer chain undergo cation exchange with the low-valence cations on the clay surface, and the polymer is firmly adsorbed onto the surface of clay particles through van der Waals forces, forming a protective film, thereby inhibiting the dispersion of clay and the migration of particles.

[0004] Patent document CN105198757A discloses a small cationic bis-quaternary ammonium salt clay stabilizer and its preparation method. The small cationic bis-quaternary ammonium salt clay stabilizer is prepared using epichlorohydrin, small molecule tertiary amine and hydrochloric acid as raw materials. The prepared small cationic bis-quaternary ammonium salt clay stabilizer has a high positive charge density, good stability and clay swelling inhibition ability. When the addition amount of the small cationic bis-quaternary ammonium salt clay stabilizer is 0.5%, the swelling prevention rate reaches more than 85%, and its temperature resistance point reaches 125℃.

[0005] Patent document CN117886980A discloses a quaternary ammonium salt clay stabilizer, its preparation method, and its application. This stabilizer is a polymer generated by the self-polymerization of dimethyl diallyl ammonium chloride. The weight-average molecular weight is less than 20,000; the radius of gyration of the quaternary ammonium salt clay stabilizer is 0.4 nm to 0.6 nm; the cationicity of the quaternary ammonium salt clay stabilizer is 3 mmol / g to 4 mmol / g; the anti-swelling rate is >85%; the water wash resistance is >80%; and the temperature resistance is ≥160℃. This quaternary ammonium salt clay stabilizer is suitable not only for high-permeability cores but also for low-permeability cores, exhibiting good temperature resistance. The quaternary ammonium salt clay stabilizer prepared by the self-polymerization of dimethyl diallyl ammonium chloride also has a high charge density, causing clay particles to bind together and resist separation, thus resulting in good anti-swelling rate and water wash resistance.

[0006] The clay stabilizers introduced above all have good anti-swelling effects, but their temperature resistance does not meet the current requirements for oil and gas field development. There is an urgent need to develop clay stabilizers with a temperature resistance of over 200℃. Summary of the Invention

[0007] This invention provides a trihydroxyquaternary ammonium salt small molecule clay stabilizer, its preparation method, and its application, overcoming the shortcomings of the prior art. The trihydroxyquaternary ammonium salt small molecule clay stabilizer is an aqueous solution of trihydroxyquaternary ammonium salt. The trihydroxyquaternary ammonium salt contains a strongly polar molecule with four cations and three hydroxyl groups, has a high anti-swelling rate, and can withstand temperatures up to 207°C.

[0008] One of the technical solutions of this invention is achieved through the following measures: a trihydroxyquaternary ammonium salt small molecule clay stabilizer, which is an aqueous solution of trihydroxyquaternary ammonium salt, the structural formula of which is as follows: .

[0009] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The above-mentioned trihydroxy-quaternary ammonium salt small molecule clay stabilizer was prepared by the following method: methylamine hydrochloride and 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to obtain a reaction solution, wherein the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride was 3.0 to 3.2, and the reaction solution was reacted to obtain the trihydroxy-quaternary ammonium salt small molecule clay stabilizer.

[0010] Trihydroxyquaternary ammonium salt small molecule clay stabilizer is an aqueous solution of trihydroxyquaternary ammonium salt.

[0011] The molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride is 3.0 to 3.2.

[0012] The reaction temperature is 60℃ to 80℃, and the reaction time is 6h to 12h.

[0013] In the above reactant solution, the total mass fraction of the reactants is 40% to 80%.

[0014] The second technical solution of the present invention is achieved through the following measures: a method for preparing a trihydroxy-quaternary ammonium salt small molecule clay stabilizer, which is carried out according to the following method: methylamine hydrochloride and 2,3-epoxypropyltrimethylammonium chloride are dissolved in water to obtain a reaction solution, wherein the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride is 3.0 to 3.2, and the reaction solution is reacted to obtain the trihydroxy-quaternary ammonium salt small molecule clay stabilizer.

[0015] The following are further optimizations and / or improvements to the second technical solution of the above invention: The molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride is 3.0 to 3.2.

[0016] The reaction temperature is 60℃ to 80℃, and the reaction time is 6h to 12h.

[0017] In the above reactant solution, the total mass fraction of the reactants is 40% to 80%.

[0018] The third technical solution of the present invention is achieved through the following measures: the application of a trihydroxyquaternary ammonium salt small molecule clay stabilizer in the fracturing construction of low-permeability or ultra-low-permeability reservoirs.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1) The trihydroxyquaternary ammonium salt small molecule clay stabilizer prepared by the present invention is an aqueous solution of trihydroxyquaternary ammonium salt. The trihydroxyquaternary ammonium salt contains a strongly polar molecule with four cations and three hydroxyl groups. It has a small molecular weight, high charge density, strong water washing ability, significant effect in preventing clay swelling, and temperature resistance up to 207℃.

[0020] 2) The trihydroxyquaternary ammonium salt small molecule clay stabilizer of the present invention has a simple preparation method, a safe and controllable reaction process, and is suitable for large-scale production.

[0021] 3) The trihydroxyquaternary ammonium salt small molecule clay stabilizer described in this invention has a small molecular weight and will not cause secondary damage to the reservoir.

[0022] 4) The trihydroxyquaternary ammonium salt small molecule clay stabilizer described in this invention has little effect on the viscosity of the base fluid of the emulsion fracturing fluid, ensuring the sand-carrying performance of the fracturing fluid, and can be used for fracturing construction in low-permeability and ultra-low-permeability reservoirs. Detailed Implementation

[0023] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of this invention. All chemical reagents and chemical products mentioned in this invention, unless otherwise specified, are well-known and commonly used chemical reagents and chemical products in the prior art; percentages in this invention, unless otherwise specified, are mass percentages; solutions in this invention, unless otherwise specified, are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, generally defined as 25°C.

[0024] The present invention will be further described below with reference to embodiments: Example 1: This trihydroxyquaternary ammonium salt small molecule clay stabilizer is an aqueous solution of trihydroxyquaternary ammonium salt. The structural formula of trihydroxyquaternary ammonium salt is as follows: .

[0025] Example 2: The trihydroxyquaternary ammonium salt small molecule clay stabilizer was prepared by the following method: methylamine hydrochloride and 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to obtain a reaction solution. The molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride was 3.0 to 3.2. The reaction solution was reacted to obtain the trihydroxyquaternary ammonium salt small molecule clay stabilizer.

[0026] The chemical reaction process of the trihydroxyquaternary ammonium salt small molecule clay stabilizer is as follows: Example 3: The trihydroxy-quaternary ammonium salt small molecule clay stabilizer was prepared by the following method: methylamine hydrochloride and 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to obtain a reactant solution. The total mass fraction of the reactants in the reactant solution was 40% to 80%, and the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride was 3.0 to 3.2. The mixture was heated to 60°C to 80°C and reacted for 6 to 12 hours to obtain the trihydroxy-quaternary ammonium salt small molecule clay stabilizer.

[0027] Example 4: The trihydroxy-quaternary ammonium salt small molecule clay stabilizer was prepared by the following method: methylamine hydrochloride and 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to obtain a reactant solution. The total mass fraction of the reactants in the reactant solution was 40% or 80%, and the molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride was 3.0 or 3.2. The mixture was heated to 60°C or 80°C and reacted for 6 h or 12 h to obtain the trihydroxy-quaternary ammonium salt small molecule clay stabilizer.

[0028] Example 5: The trihydroxyquaternary ammonium salt small molecule clay stabilizer was prepared by the following method: 0.10 mol of methylamine hydrochloride and 0.30 mol of 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to prepare a reactant solution with a total mass fraction of 60%, and reacted at 80°C for 9 h to obtain the trihydroxyquaternary ammonium salt small molecule clay stabilizer.

[0029] Example 6: The trihydroxyquaternary ammonium salt small molecule clay stabilizer was prepared by the following method: 0.10 mol of methylamine hydrochloride and 0.32 mol of 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to prepare a reactant solution with a total mass fraction of 40%, and reacted at 60°C for 12 h to obtain the trihydroxyquaternary ammonium salt small molecule clay stabilizer.

[0030] Example 7: The trihydroxyquaternary ammonium salt small molecule clay stabilizer was prepared by the following method: 0.10 mol of methylamine hydrochloride and 0.22 mol of 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to prepare a reactant solution with a total mass fraction of 80%, and reacted at 75°C for 6 h to obtain the trihydroxyquaternary ammonium salt small molecule clay stabilizer.

[0031] The trihydroxyquaternary ammonium salt small molecule clay stabilizer prepared in Examples 5 to 7 of this invention has a high anti-swelling rate of over 83.17%, which significantly prevents clay from swelling. It also has strong water washing resistance (water washing anti-swelling rate of over 81.94%), which is not much different from the anti-swelling rate, and its temperature resistance reaches over 207℃.

[0032] The performance of the trihydroxyquaternary ammonium salt small molecule clay stabilizer prepared in Example 5 was tested.

[0033] 1) Expansion prevention rate The evaluation method refers to the centrifugation method for testing the anti-swelling rate in SY / T5971-2016 "Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields".

[0034] Method: Take 0.5 mL of clay stabilizer (i.e., the trihydroxyquaternary ammonium salt small molecule clay stabilizer prepared in Example 5), add 99.5 g of distilled water and shake well to obtain a clay stabilizer solution. Weigh 0.50 g of sodium bentonite, put it into a 10 mL centrifuge tube, add 10 mL of clay stabilizer solution, shake well, let stand at room temperature for 2 h, put it into a centrifuge, centrifuge at 1500 r / min for 15 min, and read the volume V1 of the expanded sodium bentonite.

[0035] Weigh 0.50g of sodium bentonite, put it into a 10mL centrifuge tube, add 10mL of distilled water, shake well, let it stand at room temperature for 2 hours, put it into a centrifuge, centrifuge at 1500r / min for 15 minutes, and read the volume V2 of the sodium bentonite after expansion.

[0036] Weigh 0.50g of sodium bentonite, put it into a 10mL centrifuge tube, add 10mL of kerosene, shake well, let it stand at room temperature for 2 hours, put it into a centrifuge, centrifuge at 1500r / min for 15 minutes, and read the volume V0 of the expanded sodium bentonite.

[0037] The anti-swelling rate B is calculated using the following formula: 2) Water washability Method: In the above method for testing the anti-swelling rate, after reading the volume V1 of the expanded sodium bentonite, the supernatant in the centrifuge tube was discarded, and the tube was washed three times with distilled water. The volume V3 of the expanded sodium bentonite was then read. Each distilled water wash was performed as follows: 10 mL of distilled water was added, the mixture was shaken thoroughly, allowed to stand for 2 hours, and then placed in a centrifuge. The tube was centrifuged at 1500 r / min for 15 minutes.

[0038] The anti-swelling rate B1 for washing is calculated using the following formula: 3) Temperature resistance test The trihydroxy-quaternary ammonium salt small molecule clay stabilizer prepared in Example 5 was heated at high temperature for 6 hours (drying oven), and then the swelling rate of the heated trihydroxy-quaternary ammonium salt small molecule clay stabilizer was tested. Repeated testing showed no significant change in the swelling rate B (difference less than 5%).

[0039] The anti-swelling rate of the trihydroxyquaternary ammonium salt small molecule clay stabilizer prepared in Example 5 was 83.17%, the anti-swelling rate after water washing was 81.94%, and the temperature resistance reached 207℃.

[0040] In summary, the trihydroxyquaternary ammonium salt small molecule clay stabilizer prepared by this invention has strong water washing resistance, significant effect in preventing clay swelling, and a temperature resistance of up to 207℃.

[0041] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A trihydroxy-quaternary ammonium salt small molecule clay stabilizer, characterized in that, This is an aqueous solution of trihydroxyquaternary ammonium salt. The structural formula of trihydroxyquaternary ammonium salt is as follows: 。 2. The trihydroxy-4-quaternary ammonium salt small molecule clay stabilizer according to claim 1, characterized in that, The following method was used to prepare the reaction solution: methylamine hydrochloride and 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to obtain a reaction solution. The molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride was 3.0 to 3.

2. The reaction solution was reacted to obtain a trihydroxyquaternary ammonium salt small molecule clay stabilizer.

3. The trihydroxy-quaternary ammonium salt small molecule clay stabilizer according to claim 2, characterized in that... The molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride is 3.0 to 3.

2.

4. The trihydroxy-quaternary ammonium salt small molecule clay stabilizer according to claim 2 or 3, characterized in that... The reaction temperature is 60℃ to 80℃, and the reaction time is 6h to 12h.

5. The trihydroxy-quaternary ammonium salt small molecule clay stabilizer according to claim 2 or 3, characterized in that... In the reactant solution, the total mass fraction of the reactants is 40% to 80%.

6. The trihydroxy-quaternary ammonium salt small molecule clay stabilizer according to claim 4, characterized in that... In the reactant solution, the total mass fraction of the reactants is 40% to 80%.

7. A method for preparing the trihydroxyquaternary ammonium salt small molecule clay stabilizer according to claim 1, characterized in that... The following method was used to prepare the reaction solution: methylamine hydrochloride and 2,3-epoxypropyltrimethylammonium chloride were dissolved in water to obtain a reaction solution. The molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride was 3.0 to 3.

2. The reaction solution was reacted to obtain a trihydroxyquaternary ammonium salt small molecule clay stabilizer.

8. The preparation method of the trihydroxyquaternary ammonium salt small molecule clay stabilizer according to claim 7, characterized in that... The molar ratio of 2,3-epoxypropyltrimethylammonium chloride to methylamine hydrochloride is 3.0 to 3.

2.

9. The method for preparing the trihydroxyquaternary ammonium salt small molecule clay stabilizer according to claim 7 or 8, characterized in that... The reaction temperature is 60℃ to 80℃, and the reaction time is 6h to 12h; or / and, the total mass fraction of the reactants in the reactant solution is 40% to 80%.

10. The application of a trihydroxyquaternary ammonium salt small molecule clay stabilizer according to any one of claims 1 to 6 and its preparation method in fracturing operations of low-permeability or ultra-low-permeability reservoirs.

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