Efficient oil-soluble paraffin remover and inhibitor as well as preparation method and application thereof

Abstract

The invention provides an efficient oil-soluble paraffin remover and inhibitor as well as a preparation method and application thereof, and the efficient oil-soluble paraffin remover and inhibitor is mainly prepared from the following raw materials in parts by mass: 20-35 parts of oil-soluble polyether, 15-25 parts of a modified olefin copolymer, 5-12 parts of alkylbenzene sulfonate, 3-8 parts of fatty alcohol-polyoxyethylene ether, 8-15 parts of a cosolvent, 2-5 parts of a corrosion inhibitor and a proper amount of base oil. According to the efficient oil-soluble paraffin remover and inhibitor disclosed by the invention, a good paraffin remover and inhibitor effect can be ensured, and cost increase caused by too high dosage can be avoided; and the application range is wide, and the crude oil extraction requirements under different wax content and temperature conditions can be met.

Description

Technical Field

[0001] This invention relates to the field of wax removal and prevention technology, specifically to a high-efficiency oil-soluble wax removal and prevention agent, its preparation method, and its application. Background Technology

[0002] During crude oil extraction, crude oil contains a certain amount of wax. As the oil is extracted from the reservoir to the surface, the temperature and pressure gradually decrease, reducing the solubility of wax. This wax crystallizes and deposits on the surfaces of equipment such as wellbore, production pipelines, and sucker rods, forming wax deposits. Wax deposits can lead to problems such as reduced wellbore flow area, increased pumping unit load, and pipeline blockage. In severe cases, it can cause well shutdowns, increase extraction costs, and reduce oil recovery rates. Therefore, developing efficient wax-removing and anti-wax agents is crucial to solving the wax deposit problem in crude oil extraction.

[0003] Currently, commonly used wax removers and preservatives are mainly divided into three categories: oil-soluble, water-soluble, and solid. Among them, oil-soluble wax removers and preservatives are widely used in the extraction of high-wax crude oil due to their good compatibility with crude oil and direct action. However, existing oil-soluble wax removers and preservatives generally have problems such as difficulty in achieving both wax removal and wax prevention rates, poor thermal stability, narrow applicable temperature range, and corrosion of equipment. For example, some oil-soluble wax removers and preservatives can only achieve good wax removal effects, but the wax prevention period is short; while some products with good wax prevention effects are easily decomposed under high temperature conditions, losing their wax prevention properties, and have a high corrosion rate on metal pipelines, increasing equipment maintenance costs.

[0004] To address the aforementioned issues, patent CN108795645A discloses an oil-soluble wax remover and inhibitor, primarily composed of poly-α-olefin and maleic anhydride copolymer. While this improves the wax-preventing rate, its wax-removing effect is poor, and its performance significantly degrades at temperatures exceeding 120°C. Patent CN110256843A discloses a composite oil-soluble wax remover and inhibitor, incorporating surfactants and corrosion inhibitors to improve both wax-removing and corrosion-inhibiting properties. However, its wax-preventing duration is short, requiring frequent refills and increasing operational complexity. Therefore, developing an oil-soluble wax remover and inhibitor that combines high wax removal rate, high wax-preventing rate, good thermal stability, and corrosion inhibition properties is of significant practical importance.

[0005] In view of this, the present invention is hereby proposed. Summary of the Invention

[0006] The primary objective of this invention is to provide a highly efficient oil-soluble wax remover and anti-wax agent that combines high wax removal rate, high wax prevention rate, good thermal stability, and corrosion inhibition properties.

[0007] The second objective of this invention is to provide a method for preparing the above-mentioned high-efficiency oil-soluble dewaxing agent. This method is simple to operate, operates under mild conditions, is pollution-free, produces no waste, and is safe and environmentally friendly.

[0008] In order to achieve the above-mentioned objectives of the present invention, the following technical solution is adopted: This invention provides a high-efficiency oil-soluble dewaxing agent, which is mainly made from the following raw materials: by mass parts, 20-35 parts of oil-soluble polyether, 15-25 parts of modified olefin copolymer, 5-12 parts of alkylbenzene sulfonate, 3-8 parts of fatty alcohol polyoxyethylene ether, 8-15 parts of cosolvent, 2-5 parts of corrosion inhibitor, and an appropriate amount of base oil.

[0009] Preferably, as a further feasible option, the following components are included by weight: 25-30 parts of oil-soluble polyether, 17-20 parts of modified olefin copolymer, 7-10 parts of alkylbenzene sulfonate, 4-7 parts of fatty alcohol polyoxyethylene ether, 9-13 parts of cosolvent, 3-4 parts of corrosion inhibitor, and an appropriate amount of base oil.

[0010] Preferably, as a further feasible option, the mixture comprises, by weight, 27 parts of oil-soluble polyether, 18 parts of modified olefin copolymer, 8 parts of alkylbenzene sulfonate, 6 parts of fatty alcohol polyoxyethylene ether, 12 parts of cosolvent, 3 parts of corrosion inhibitor, and an appropriate amount of base oil.

[0011] The core innovation of this invention lies in the synergistic design of its components: oil-soluble polyether, as the main wax-removing component, has oxygen atoms in its molecular chain that can form hydrogen bonds with hydroxyl groups on the surface of wax crystals, disrupting the regular structure of the wax crystals and promoting the dissolution of deposited wax; modified olefin copolymer, as the main wax inhibitor, has polar groups in its molecules that can adsorb onto the surface of wax crystals, preventing the growth and aggregation of wax crystals and extending the wax-inhibiting cycle; alkylbenzene sulfonate and fatty alcohol polyoxyethylene ether, as compound surfactants, can reduce the interfacial tension between crude oil and wax crystals, improve the dispersibility of oil-soluble polyether and modified olefin copolymer, and enhance the synergistic effect of wax removal and prevention; co-solvent can improve the solubility of each component in base oil and avoid stratification; and corrosion inhibitor can form a protective film on the surface of metal equipment, reducing the corrosion of the equipment by the wax removal and prevention agents.

[0012] Preferably, as a further feasible option, the oil-soluble polyether is a polyoxypropylene-polyoxyethylene block polyether with a number-average molecular weight of 800-2000, wherein the propylene oxide segment accounts for 60-80%. In this block structure, the propylene oxide segment imparts good oil solubility and thermal stability, while the ethylene oxide segment provides polar groups to enhance the interaction with wax crystals. By controlling the molecular weight within the range of 800-2000, both the dewaxing effect can be guaranteed, and the poor flowability caused by a large molecular weight can be avoided.

[0013] Preferably, as a further feasible option, the modified olefin copolymer is an alkylamine-modified product of maleic anhydride-α-olefin copolymer, wherein the carbon chain length of the α-olefin is C12-C20, and the degree of modification is 40-60%. Maleic anhydride-α-olefin copolymer itself has certain anti-wax properties. After alkylamine modification, more polar amine groups are introduced, improving the adsorption capacity for wax crystals. The carbon chain length of the α-olefin matches the carbon chain length of wax in crude oil, allowing it to more effectively insert into the wax crystal lattice and disrupt wax crystal growth. Controlling the degree of modification at 40-60% balances polarity and oil solubility, avoiding excessive modification that could lead to a decrease in oil solubility.

[0014] Preferably, as a further feasible option, the alkylbenzene sulfonate is at least one of sodium dodecylbenzene sulfonate and potassium tetradecylbenzene sulfonate. Its purity is preferably maintained at 98 wt% or higher. This type of surfactant has good emulsifying and dispersing properties, which can promote the uniform distribution of the dewaxing and anti-waxing agent in crude oil. The fatty alcohol polyoxyethylene ether is selected from lauryl alcohol polyoxyethylene ether (EO number 3-5), which, when compounded with the alkylbenzene sulfonate, can produce a synergistic effect and further reduce interfacial tension.

[0015] Preferably, as a further feasible option, the co-solvent is one or a mixture of isopropanol, n-butanol, or ethylene glycol monobutyl ether. This type of co-solvent has good compatibility with base oils and polar components, effectively improving the solubility and dispersibility of each component and preventing product stratification. The corrosion inhibitor is a compound of benzotriazole and fatty amine polyoxyethylene ether, with a mass ratio of 1:2-3. Benzotriazole can form a chelating film on the metal surface, and fatty amine polyoxyethylene ether can enhance the stability of the film. The combination of the two can significantly reduce the corrosion rate of the wax remover on carbon steel and other metal materials.

[0016] Preferably, as a further feasible option, the base oil is 150SN mineral oil or hydrotreated base oil with a kinematic viscosity of 10-15 mm² / s at 40°C. This type of base oil exhibits good stability and oil solubility, serving as a carrier for the various components and ensuring the product's flowability and storage stability.

[0017] This invention provides a method for preparing a highly efficient oil-soluble wax remover, comprising the following steps: Weigh the base oil and co-solvent, and stir for 10-15 minutes at a speed of 300-500 r / min and a temperature of 50-60℃ to obtain a mixed solvent. Oil-soluble polyether and modified olefin copolymer are added sequentially to the mixed solvent, and the mixture is stirred for 20-30 minutes until the solid is completely dissolved to obtain an intermediate mixture. Lower the temperature to 30-40℃, add alkylbenzene sulfonate and fatty alcohol polyoxyethylene ether, continue stirring for 15-20 minutes to obtain the preproduct, then add corrosion inhibitor, stir for 10-15 minutes, and let stand to cool.

[0018] Specifically, the above preparation method can be carried out in practice according to the following steps: 1. Weigh the base oil and co-solvent by weight percentage, add them to the reaction vessel, and stir for 10-15 minutes at a speed of 300-500 r / min and a temperature of 50-60℃ to obtain a mixed solvent. This step, through heating and stirring, ensures that the co-solvent and base oil are fully integrated, providing a good carrier for the dissolution of subsequent components.

[0019] 2. Add the oil-soluble polyether and the modified olefin copolymer to the mixed solvent in sequence, and stir for 20-30 minutes while keeping the speed and temperature constant until the solid is completely dissolved to obtain an intermediate mixture. Control the temperature at 50-60℃ to ensure the rapid dissolution of the oil-soluble polyether and the modified olefin copolymer, while avoiding the destruction of their molecular structure due to high temperature.

[0020] 3. Lower the temperature of the reactor to 30-40℃, add alkylbenzene sulfonate and fatty alcohol polyoxyethylene ether, and continue stirring for 15-20 minutes to obtain the preproduct; lowering the temperature can prevent the surfactant from hydrolyzing due to high temperature and ensure its performance stability.

[0021] 4. Add corrosion inhibitor to the pre-product, stir for 10-15 minutes, let stand and cool to room temperature, filter to remove impurities, and obtain oil-soluble wax remover; the filtration step can remove minute impurities that may be generated during the preparation process and improve product purity.

[0022] The present invention also provides the application of the above-mentioned high-efficiency oil-soluble dewaxing agent and the high-efficiency oil-soluble dewaxing agent prepared by the above preparation method in the direction of oil well production pipeline or reservoir.

[0023] The aforementioned wax-removing and anti-wax agent is injected into the oil well production pipeline or reservoir at a dosage of 0.05-0.2% of crude oil. It is suitable for crude oil with a wax content of 15-40% and an applicable temperature range of 50-150℃. This dosage range ensures good wax removal and prevention effects while avoiding increased costs due to excessive dosage. It has a wide range of applications and can meet the needs of crude oil extraction under different wax contents and temperature conditions.

[0024] In summary, the preparation method of the present invention is simple and easy to operate, requires no complex equipment, is suitable for industrial production, and the parameters of each step are reasonably designed to fully ensure the dissolution and synergistic effect of each component. Detailed Implementation

[0025] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0026] Example 1 A high-efficiency oil-soluble wax remover, the components of which are present in the following weight percentages: 27% polyoxypropylene polyoxyethylene block polyether (number average molecular weight 1000, 70% propylene oxide segment), 18% hexadecylamine modified product of maleic anhydride-C16 olefin copolymer (modification degree 50%), 8% sodium dodecylbenzenesulfonate, 6% lauryl alcohol polyoxyethylene ether (EO number 4), 12% isopropanol, 3% HEDP and fatty amine polyoxyethylene ether compound (compound ratio 1:2), and 26% 150SN mineral oil (kinematic viscosity 12mm² / s at 40℃).

[0027] Preparation method: 1. Weigh mineral oil and isopropanol, add them to a reaction vessel, and stir for 12 minutes at a speed of 400 r / min and a temperature of 55℃ to obtain a mixed solvent; 2. Add the modified product of polyoxypropylene polyoxyethylene block polyether and maleic anhydride-C16 olefin copolymer, maintain the speed and temperature, and stir for 25 minutes until completely dissolved to obtain an intermediate mixture; 3. Cool to 35°C, add sodium dodecylbenzenesulfonate and lauryl alcohol polyoxyethylene ether, stir for 18 min to obtain the preproduct; 4. Add corrosion inhibitor, stir for 12 minutes, let stand and cool to room temperature, and filter to obtain oil-soluble anti-wax agent.

[0028] Example 2 A high-efficiency oil-soluble wax remover, the weight percentages of each component are as follows: 20% polyoxypropylene polyoxyethylene block polyether (number average molecular weight 800, 60% propylene oxide segment), 15% dodecylamine modified product of maleic anhydride-C12 olefin copolymer (modification degree 40%), 5% potassium tetradecylbenzene sulfonate, 3% lauryl alcohol polyoxyethylene ether (EO number 3), 8% n-butanol, 2% HEDP and fatty amine polyoxyethylene ether compound (compound ratio 1:2.5), and 47% hydrogenated base oil (kinematic viscosity 10 mm² / s at 40℃).

[0029] The preparation method is the same as in Example 1, only the amount of each component and the corresponding parameters are adjusted.

[0030] Example 3 A high-efficiency oil-soluble wax remover, the weight percentages of each component are as follows: 35% polyoxypropylene polyoxyethylene block polyether (number average molecular weight 2000, propylene oxide segment content 80%), 25% eicosamine-modified product of maleic anhydride-C20 olefin copolymer (modification degree 60%), 12% sodium dodecylbenzenesulfonate, 8% lauryl alcohol polyoxyethylene ether (EO number 5), 15% ethylene glycol monobutyl ether, 5% HEDP and fatty amine polyoxyethylene ether compound (compound ratio 1:3), and 0% 150SN mineral oil (kinematic viscosity 15mm² / s at 40℃).

[0031] The preparation method is the same as in Example 1, only the amount of each component and the corresponding parameters are adjusted.

[0032] Example 4 A high-efficiency oil-soluble wax remover, the weight percentages of each component are as follows: 30% polyoxypropylene polyoxyethylene block polyether (number average molecular weight 2000, propylene oxide segment content 80%), 17% eicosamine-modified product of maleic anhydride-C20 olefin copolymer (modification degree 60%), 10% sodium dodecylbenzenesulfonate, 4% lauryl alcohol polyoxyethylene ether (EO number 5), 13% ethylene glycol monobutyl ether, 3% HEDP and fatty amine polyoxyethylene ether compound (compound ratio 1:3), and 23% 150SN mineral oil (kinematic viscosity 15mm² / s at 40℃).

[0033] The preparation method is the same as in Example 1, only the amount of each component and the corresponding parameters are adjusted.

[0034] Example 5 A high-efficiency oil-soluble wax remover, comprising the following components by weight percentage: 25% polyoxypropylene-polyoxyethylene block polyether (number average molecular weight 2000, propylene oxide segment percentage 80%), 20% eicosamine-modified product of maleic anhydride-C20 olefin copolymer (modification degree 60%), 7% sodium dodecylbenzenesulfonate, 7% lauryl alcohol polyoxyethylene ether (EO number 5), 9% ethylene glycol monobutyl ether, 4% HEDP and fatty amine polyoxyethylene ether compound (compound ratio 1:3), and 28% 150SN mineral oil (kinematic viscosity 15 mm² / s at 40℃).

[0035] The preparation method is the same as in Example 1, only the amount of each component and the corresponding parameters are adjusted.

[0036] Comparative Example 1 An oil-soluble dewaxing agent, compared with Example 1, does not contain modified olefin copolymer, but other components and dosages remain unchanged, and the preparation method is the same as in Example 1.

[0037] Comparative Example 2 An oil-soluble dewaxing agent, compared with Example 1, does not contain oil-soluble polyether, but other components and dosages remain unchanged, and the preparation method is the same as in Example 1.

[0038] Comparative Example 3 An oil-soluble wax remover, using the formula and preparation method disclosed in patent CN108795645A.

[0039] Performance testing The performance of the wax removers in Examples 1-3 and Comparative Examples 1-3 was tested using the following methods: 1. Wax Removal Rate Test: Referring to SY / T 6300-2009 "Technical Conditions for Wax Removal and Inhibitor Agents for Oil Production", the static wax removal method was adopted. Crude oil with a wax content of 25% was mixed with a wax removal and inhibitor agent (addition dosage of 0.1%) at 80℃. After reacting for 2 hours, the wax removal rate was calculated. 2. Wax prevention rate test: Referring to SY / T 6300-2009, the dynamic wax prevention method is adopted. At 100℃, crude oil with a wax content of 25% is mixed with a wax inhibitor (addition dosage of 0.1%), circulated for 4 hours, and then cooled to room temperature. The wax prevention rate is then calculated. 3. Thermal stability test: The wax remover and wax inhibitor were kept at 150℃ for 48 hours, and then the wax removal rate and wax prevention rate were tested to calculate the performance retention rate; 4. Corrosion Inhibition Rate Test: Referring to SY / T 5273-2014 "Performance Indicators and Evaluation Methods for Corrosion Inhibitors Used in Oilfield Produced Water Treatment", the corrosion inhibition rate of the anti-wax agent on carbon steel was tested using the weight loss method on the coated tablets in an acidic medium at 80℃. The test results are shown in Table 1 below: Table 1 Test Results

[0040] The test results show that the wax removal and anti-wax agents of Examples 1-3 of this invention all have a wax removal rate of over 95%, an anti-wax rate of over 90%, a performance retention rate of over 94% after heat stabilization, and a corrosion inhibition rate of over 88%. All these performance characteristics are superior to those of Comparative Examples 1-3. Specifically, Comparative Example 1, lacking modified olefin copolymers, exhibits a significantly lower anti-wax rate; Comparative Example 2, lacking oil-soluble polyethers, shows a significantly reduced wax removal rate; and Comparative Example 3, using existing technology formulations, has lower wax removal and anti-wax performance, heat stability, and corrosion inhibition performance than the products of this invention.

[0041] Although the invention has been illustrated and described with reference to specific embodiments, it should be understood that many other changes and modifications can be made without departing from the spirit and scope of the invention.

Claims

1. A high-efficiency oil-soluble wax remover, characterized in that, It is mainly made from the following raw materials: by mass parts, 20-35 parts of oil-soluble polyether, 15-25 parts of modified olefin copolymer, 5-12 parts of alkylbenzene sulfonate, 3-8 parts of fatty alcohol polyoxyethylene ether, 8-15 parts of cosolvent, 2-5 parts of corrosion inhibitor, and an appropriate amount of base oil.

2. The high-efficiency oil-soluble wax remover and anti-wax agent according to claim 1, characterized in that, By weight, it contains 25-30 parts of oil-soluble polyether, 17-20 parts of modified olefin copolymer, 7-10 parts of alkylbenzene sulfonate, 4-7 parts of fatty alcohol polyoxyethylene ether, 9-13 parts of cosolvent, 3-4 parts of corrosion inhibitor, and an appropriate amount of base oil.

3. The high-efficiency oil-soluble wax remover according to claim 1, characterized in that, By weight, it contains 27 parts oil-soluble polyether, 18 parts modified olefin copolymer, 8 parts alkylbenzene sulfonate, 6 parts fatty alcohol polyoxyethylene ether, 12 parts cosolvent, 3 parts corrosion inhibitor, and an appropriate amount of base oil.

4. The high-efficiency oil-soluble wax remover according to any one of claims 1-3, characterized in that, The oil-soluble polyether is a polyoxypropylene-polyoxyethylene block polyether with a number average molecular weight of 800-2000, wherein the propylene oxide segment accounts for 60-80%.

5. The high-efficiency oil-soluble wax remover according to any one of claims 1-3, characterized in that, The modified olefin copolymer is an alkylamine-modified product of maleic anhydride-α-olefin copolymer, wherein the carbon chain length of the α-olefin is C12-C20 and the degree of modification is 40-60%.

6. The high-efficiency oil-soluble wax remover according to any one of claims 1-3, characterized in that, The alkylbenzene sulfonate is at least one of sodium dodecylbenzene sulfonate and potassium tetradecylbenzene sulfonate.

7. The high-efficiency oil-soluble wax remover according to any one of claims 1-3, characterized in that, The co-solvent is one or a mixture of isopropanol, n-butanol, or ethylene glycol monobutyl ether.

8. The high-efficiency oil-soluble wax remover according to any one of claims 1-3, characterized in that, The base oil is 150SN mineral oil or hydrotreated base oil, with a kinematic viscosity of 10-15 mm² / s at 40°C.

9. The method for preparing the high-efficiency oil-soluble dewaxing agent according to any one of claims 1-8, characterized in that, Includes the following steps: Weigh the base oil and co-solvent, and stir for 10-15 minutes at a speed of 300-500 r / min and a temperature of 50-60℃ to obtain a mixed solvent. Oil-soluble polyether and modified olefin copolymer are added sequentially to the mixed solvent, and the mixture is stirred for 20-30 minutes until the solid is completely dissolved to obtain an intermediate mixture. Lower the temperature to 30-40℃, add alkylbenzene sulfonate and fatty alcohol polyoxyethylene ether, continue stirring for 15-20 minutes to obtain the preproduct, then add corrosion inhibitor, stir for 10-15 minutes, and let stand to cool.

10. The application of the high-efficiency oil-soluble dewaxing agent according to any one of claims 1-8 and the high-efficiency oil-soluble dewaxing agent prepared by the preparation method according to claim 9 in the direction of oil well production pipeline or reservoir.

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