Salt-resistant paraffin inhibitor for oil extraction and preparation method thereof

Abstract

The invention relates to the technical field of paraffin inhibitors and preparation thereof, in particular to a salt-tolerant oil extraction paraffin inhibitor and a preparation method thereof.The salt-tolerant oil extraction paraffin inhibitor is prepared from, by weight, 25%-30% of sodium alpha-olefin sulfonate, 10%-15% of betaine, 8%-10% of alkyl polyglucoside sulfonate and the balance water. The preparation method comprises the following steps: preparing a first mixed solution, adding a required amount of betaine into the first mixed solution, dissolving, uniformly mixing and stirring to obtain a second mixed solution, adding a required amount of alkyl polyglucoside sulfonate into the second mixed solution, and uniformly mixing and stirring to obtain the salt-tolerant oil extraction paraffin inhibitor. By adopting a compounding system of alpha-sodium olefin sulfonate, betaine and alkyl polyglucoside sulfonate, the obtained product avoids calcium and magnesium ion complexation reaction, has excellent stability and no layering or salting-out phenomenon in a calcium chloride water type oil well, meets the development requirement of a high-salinity oil reservoir, and improves the oil well exploitation efficiency.

Description

Technical Field

[0001] This invention relates to the field of wax inhibitors and their preparation technology, specifically a salt-tolerant wax inhibitor for oil recovery and its preparation method. Background Technology

[0002] During crude oil extraction, decreases in temperature and pressure cause paraffin wax to precipitate and adhere to the well pipe and tubing walls, leading to tubing blockage, reduced production, and even production accidents. Therefore, paraffin removal and prevention are crucial throughout the entire lifecycle of an oil well. Currently, mainstream paraffin removal and prevention processes include hot washing, chemical methods, and microbial methods. Among these, chemical methods are the preferred choice on-site due to their ease of operation.

[0003] Existing chemical wax inhibitors are mainly divided into organic solvent-based wax removers and surfactant-based wax inhibitors. Dodecyl sulfate and OP-type surfactants, which are commonly used in Xinjiang Oilfield, have good wax-preventing effects on the produced fluid of sodium bicarbonate water-type oil wells. However, in high-salt calcium chloride water-type oil wells, the calcium and magnesium ions undergo complexation reactions with surfactant molecules, leading to the destruction of the micelle structure and a significant decrease in wax-preventing efficiency. When the salinity exceeds 20,000 mg / L, the wax-preventing rate is generally less than 40%, which cannot meet the development needs of high-salt reservoirs.

[0004] In the prior art, patent document CN117625161A discloses a water-in-oil emulsion type wax remover, its preparation method, and its application. The water-in-oil emulsion type wax remover comprises the following components by mass percentage: 40%–50% organic solvent; 0.3%–0.51% surfactant; 5%–10% miscible solvent; 0.5%–1.0% alkalinity regulator; and the balance being distilled water. The organic solvent includes kerosene and aromatic solvents, and the aromatic solvents include xylene and high-boiling-point aromatic solvents. It improves the wax removal rate by combining organic solvents and miscible solvents. However, while its core function is wax removal, it uses a diesel oil and ethyl acetate compound system, but it cannot address the wax prevention requirements under high salinity conditions.

[0005] Patent document CN120272183A discloses a viscosity-reducing and wax-inhibiting agent for oilfield well production and its preparation method, comprising the following components by mass percentage: maleic anhydride 15.08%–17.92%, nonylphenol polyoxyethylene ether 18.01%–26.88%, benzylamine solution 23.2%–25.4%, 5% ferrous sulfate aqueous solution 3.97%–5.0%, 5% ammonium persulfate aqueous solution 3.97%–5.00%, and sodium hydroxide aqueous solution 15.87%–17.19%. It achieves integrated viscosity reduction and wax inhibition using a copolymer system of maleic anhydride and nonylphenol polyoxyethylene ether. However, this system relies on organic amine components such as benzylamine solution, and is prone to salting out in high calcium and magnesium ion environments. When the calcium ion concentration exceeds 5000 mg / L, obvious stratification occurs, indicating insufficient salt resistance.

[0006] Therefore, developing a salt-resistant anti-wax agent is of great significance for improving oil well extraction efficiency. Summary of the Invention

[0007] This invention provides a salt-resistant oilfield wax inhibitor and its preparation method, overcoming the shortcomings of the prior art. It can effectively solve the problems of decreased wax-resistant efficiency and insufficient salt resistance caused by ion interference in existing chemical wax inhibitors.

[0008] One of the technical solutions of the present invention is achieved through the following measures: a salt-resistant oil extraction anti-wax agent, wherein the raw material composition, by weight percentage, is 25% to 30% sodium α-olefin sulfonate, 10% to 15% betaine, 8% to 10% alkyl polysaccharide sulfonate, and the balance is water.

[0009] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The above was prepared according to the following method: Step 1: Mix the required amount of sodium α-olefin sulfonate with water and stir until homogeneous to obtain the first mixture; Step 2: Add the required amount of betaine to the first mixture, dissolve it, mix and stir evenly to obtain the second mixture; Step 3: Add the required amount of alkyl polysaccharide sulfonate to the second mixture, mix and stir evenly to obtain a salt-resistant oilfield wax inhibitor.

[0010] In step one above, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 90min to 120min.

[0011] In step two above, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 40min to 50min.

[0012] In step three above, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 30min to 60min.

[0013] The second technical solution of the present invention is achieved through the following measures: a method for preparing a salt-tolerant oilfield wax inhibitor, which is carried out according to the following method: Step 1: Mix the required amount of sodium α-olefin sulfonate with water and stir until homogeneous to obtain the first mixture; Step 2: Add the required amount of betaine to the first mixture, dissolve it, mix and stir evenly to obtain the second mixture; Step 3: Add the required amount of alkyl polysaccharide sulfonate to the second mixture, mix and stir evenly to obtain a salt-resistant oilfield wax inhibitor.

[0014] The following are further optimizations and / or improvements to the second technical solution of the above invention: In step one above, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 90min to 120min.

[0015] In step two above, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 40min to 50min.

[0016] In step three above, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 30min to 60min.

[0017] This invention employs a compound system of sodium α-olefin sulfonate, betaine, and alkyl polysaccharide sulfonate. The resulting product avoids calcium and magnesium ion complexation reactions, exhibits excellent stability in calcium chloride water-type oil wells, and shows no stratification or salting-out phenomena. This meets the development requirements of high-salinity oil reservoirs and improves oil well extraction efficiency. Detailed Implementation

[0018] 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. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are well-known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention 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.

[0019] The present invention will be further described below with reference to embodiments: Example 1: The salt-resistant oilfield wax inhibitor is composed of 25% to 30% sodium α-olefin sulfonate, 10% to 15% betaine, 8% to 10% alkyl polysaccharide sulfonate, and the balance being water, by weight percentage.

[0020] Example 2: The salt-resistant oilfield wax inhibitor is composed of 25% or 30% sodium α-olefin sulfonate, 10% or 15% betaine, 8% or 10% alkyl polysaccharide sulfonate, and the balance being water, by weight percentage.

[0021] In this invention, sodium α-olefin sulfonate is water-soluble, emulsifiable, foaming, highly resistant to hard water, low in toxicity, and biodegradable. It adsorbs onto the waxed surface, forming a water film, altering the surface properties to hydrophilicity, preventing wax deposition, and simultaneously improving the salt resistance of the anti-wax agent system.

[0022] Betaine is a white powder, soluble in water. It interferes with the orderly arrangement of wax crystal molecules by interacting with them, thus slowing down the rate at which wax is separated from crude oil. It also has a synergistic effect with sodium α-olefin sulfonate to improve wettability.

[0023] Alkyl polysaccharide sulfonates are white powders, soluble in water, and wettable. They inhibit wax crystal aggregation and deposition by forming hydrogen bonds or hydrophobic interactions with wax molecules through sulfonic acid groups, while also improving the temperature resistance of the wax inhibitor system.

[0024] Example 3: As an optimization of the above examples, it was prepared according to the following method: Step 1: Mix the required amount of sodium α-olefin sulfonate with water and stir until homogeneous to obtain the first mixture; Step 2: Add the required amount of betaine to the first mixture, dissolve it, mix and stir evenly to obtain the second mixture; Step 3: Add the required amount of alkyl polysaccharide sulfonate to the second mixture, mix and stir evenly to obtain a salt-resistant oilfield wax inhibitor.

[0025] Example 4: As an optimization of the above example, in step one, the mixing temperature is 25°C to 35°C, the mixing speed is 40 r / min to 60 r / min, and the mixing time is 90 min to 120 min.

[0026] Example 5: As an optimization of the above example, in step two, the mixing temperature is 25°C to 35°C, the mixing speed is 40 r / min to 60 r / min, and the mixing time is 40 min to 50 min.

[0027] Example 6: As an optimization of the above example, in step three, the mixing temperature is 25°C to 35°C, the mixing speed is 40 r / min to 60 r / min, and the mixing time is 30 min to 60 min.

[0028] Example 7: The preparation method of this salt-tolerant oilfield wax inhibitor is carried out according to the following method: Step 1: Mix the required amount of sodium α-olefin sulfonate with water and stir until homogeneous to obtain the first mixture; Step 2: Add the required amount of betaine to the first mixture, dissolve it, mix and stir evenly to obtain the second mixture; Step 3: Add the required amount of alkyl polysaccharide sulfonate to the second mixture, mix and stir evenly to obtain a salt-resistant oilfield wax inhibitor.

[0029] Example 8: This salt-tolerant oilfield wax inhibitor was obtained by the following method: Step 1: By weight percentage, 25% sodium α-olefin sulfonate and 57% water are mixed at 25°C and stirred at a stirring speed of 40 r / min for 90 min to obtain the first mixture. Step 2: Add 10% betaine to the first mixture and mix at 25°C and a stirring speed of 40 r / min for 40 min to obtain the second mixture; Step 3: Add 8% alkyl polysaccharide sulfonate to the second mixture, and mix and stir at 40 r / min for 30 min at 25°C to obtain a salt-resistant oil production anti-wax agent.

[0030] Example 9: This salt-tolerant oilfield wax inhibitor was obtained by the following method: Step 1: By weight percentage, 28% sodium α-olefin sulfonate and 51% water are mixed at 25°C and stirred at a stirring speed of 50 r / min for 100 min to obtain the first mixture. Step 2: Add 12% betaine to the first mixture and mix at 25°C and a stirring speed of 50 r / min for 45 min to obtain the second mixture; Step 3: Add 9% alkyl polysaccharide sulfonate to the second mixture, and mix and stir at 50 r / min for 40 min at 25°C to obtain a salt-resistant oil production anti-wax agent.

[0031] Example 10: This salt-tolerant oilfield wax inhibitor was obtained by the following method: Step 1: By weight percentage, 30% sodium α-olefin sulfonate and 51% water are mixed at 35°C and stirred at a stirring speed of 60 r / min for 120 min to obtain the first mixture. Step 2: Add 12% betaine to the first mixture and mix at 35°C and a stirring speed of 60 r / min for 50 min to obtain the second mixture; Step 3: Add 9% alkyl polysaccharide sulfonate to the second mixture, and mix and stir at 35°C and a stirring speed of 60 r / min for 60 min to obtain a salt-resistant oil production anti-wax agent.

[0032] Comparative Example 1: Compared with currently used dodecyl sulfonate surfactant-type wax inhibitors.

[0033] Comparative Example 2: Compared with the currently used OP-10 surfactant-type wax inhibitor.

[0034] Performance Evaluation Currently, the testing standards for the salt-resistant oilfield wax inhibitor of this invention and the wax inhibitors obtained in Comparative Examples 1 and 2 are based on the industry standard Q / SY 6300—2024 "Technical Requirements for Oilfield Wax Inhibitors". The performance was evaluated according to the test methods of this standard, and the results are shown in Table 1.

[0035] As shown in Table 1, when the mineralization of the dodecyl sulfonate surfactant-type wax inhibitors and the OP-10 surfactant-type wax inhibitors in Comparative Examples 1 and 2 exceeds 20,000 mg / L, calcium and magnesium ions undergo complexation reactions with surfactant molecules, leading to the destruction of the micelle structure and a wax inhibition rate generally below 45%. The salt-resistant oilfield wax inhibitor of this invention can still achieve a wax prevention rate of 68% to 70% in high-salt environments with a salinity of more than 20,000 mg / L. Moreover, when the high-efficiency wax prevention and viscosity reduction work synergistically, the wax prevention rate generally exceeds 69% and the viscosity reduction rate reaches 50% to 54%, taking into account both the long-term wax prevention effect and the improvement of crude oil fluidity.

[0036] Therefore, compared with the currently used dodecyl sulfonate surfactant-type wax inhibitors and OP-10 surfactant-type wax inhibitors, the salt-resistant wax inhibitor of this invention has a better wax-preventing effect on produced fluid wells with high salinity and high calcium and magnesium ion content, making up for the shortcomings of existing wax inhibitors in field application.

[0037] In summary, the present invention employs a compound system of sodium α-olefin sulfonate, betaine, and alkyl polysaccharide sulfonate, resulting in a product that avoids calcium and magnesium ion complexation reactions, exhibits excellent stability in calcium chloride water-type oil wells, and shows no stratification or salting-out phenomena, thus meeting the development requirements of high-salinity oil reservoirs and improving oil well extraction efficiency.

[0038] The above technical features constitute the 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 salt-tolerant oilfield wax inhibitor, characterized in that... The raw material composition, by weight percentage, is 25% to 30% sodium α-olefin sulfonate, 10% to 15% betaine, 8% to 10% alkyl polysaccharide sulfonate, and the balance is water.

2. The salt-tolerant oilfield wax inhibitor according to claim 1, characterized in that... It was prepared according to the following method: Step 1: Mix the required amount of sodium α-olefin sulfonate with water and stir until homogeneous to obtain the first mixture; Step 2: Add the required amount of betaine to the first mixture, dissolve it, mix and stir evenly to obtain the second mixture; Step 3: Add the required amount of alkyl polysaccharide sulfonate to the second mixture, mix and stir evenly to obtain a salt-resistant oilfield wax inhibitor.

3. The salt-tolerant oilfield wax inhibitor according to claim 2, characterized in that... In step one, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 90min to 120min.

4. The salt-resistant oilfield wax inhibitor according to claim 2 or 3, characterized in that... In step two, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 40min to 50min.

5. The salt-tolerant oilfield wax inhibitor according to any one of claims 2 to 4, characterized in that... In step three, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 30min to 60min.

6. A method for preparing a salt-tolerant oilfield wax inhibitor according to claim 1, characterized in that... Perform the following steps: Step 1: Mix the required amount of sodium α-olefin sulfonate with water and stir until homogeneous to obtain the first mixture; Step 2: Add the required amount of betaine to the first mixture, dissolve it, mix and stir evenly to obtain the second mixture; Step 3: Add the required amount of alkyl polysaccharide sulfonate to the second mixture, mix and stir evenly to obtain a salt-resistant oilfield wax inhibitor.

7. The method for preparing the salt-tolerant oilfield wax inhibitor according to claim 6, characterized in that... In step one, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 90min to 120min.

8. The method for preparing the salt-tolerant oilfield wax inhibitor according to claim 6 or 7, characterized in that... In step two, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 40min to 50min.

9. The method for preparing the salt-tolerant oilfield wax inhibitor according to claim 6, 7, or 8, characterized in that... In step three, the mixing temperature is 25℃ to 35℃, the mixing speed is 40r / min to 60r / min, and the mixing time is 30min to 60min.