A biological paraffin inhibitor and its preparation method and application

Abstract

The application belongs to the technical field of oil exploitation, and particularly relates to a biological wax cleaning and preventing agent and a preparation method and application thereof. The biological wax cleaning and preventing agent is composed of the following raw materials in percentage by weight: modified sophorolipid 5-10%, lauryl alcohol polyoxyethylene ether 0.5-1%, and water as the balance. The preparation method of the modified sophorolipid is as follows: in a reactor, sophorolipid, tetrahydrofuran and 3-(perfluorohexyl) propylene oxide are added, stirred, heated and kept warm for reaction; deionized water and 2-chloroethyl sodium sulfonate are added in the above reactor, stirred, heated and kept warm for reaction, and pH is maintained at 7-8 to obtain the modified sophorolipid. The biological wax cleaning and preventing agent has the advantages of environmental protection, high wax dissolving rate and high wax preventing rate.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, specifically relating to a biological dewaxing agent, its preparation method, and its application. Background Technology

[0002] In the extraction and transportation of waxy crude oil, wax deposition in wellbores and pipelines is a long-standing and common technical problem plaguing the petroleum industry. During extraction, as crude oil flows from the high-temperature, high-pressure reservoir to the wellhead, the temperature and pressure continuously decrease. When these pressures drop below the wax precipitation point, the paraffin wax originally dissolved in the crude oil precipitates out as crystals, which then aggregate and deposit on the walls of the tubing, downhole equipment, and the inner walls of the pipelines. Waxing can lead to blockage of oil flow channels, increased flow resistance, and increased lift load, and in severe cases, cause well shutdowns, resulting in significant economic losses to oilfield production.

[0003] Existing wax removal technologies mainly include mechanical wax removal, thermal wax removal, and chemical wax removal. Mechanical wax removal is frequent and easily damages the pipe wall; thermal wax removal is energy-intensive, requires well shutdown and production stoppage, and may pollute the formation; chemical wax removal agents are expensive, and some are toxic or corrosive. Traditional technologies have limitations to varying degrees, such as high energy consumption, cumbersome operation, and environmental unfriendliness.

[0004] Microbial wax removal and prevention technology utilizes microbial cells or their metabolic products, such as biosurfactants, organic solvents, and degrading enzymes, to reduce crude oil viscosity and inhibit wax deposition. This technology offers advantages such as low cost, safe operation, no formation damage, and environmental friendliness, making it a research hotspot in recent years.

[0005] However, existing microbial wax-removing agents still suffer from unstable efficacy and poor long-term effectiveness in complex reservoir environments. Therefore, developing a novel biological wax-removing agent with high wax-removing efficiency, long action period, good environmental adaptability, and economic and environmental friendliness has significant engineering application value and broad market prospects for ensuring stable and increased production in waxy oilfields. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a biological wax-removing and anti-waxing agent, its preparation method, and its application. The biological wax-removing and anti-waxing agent of this invention has the advantages of being environmentally friendly, having a high wax-dissolving rate, and a high wax-preventing rate.

[0007] The first objective of this invention discloses a biological dewaxing agent, which, by weight percentage, is composed of the following raw materials: Modified sophorolipids 5-10%; Laureth polyoxyethylene ether 0.5-1%; Water balance; The modified sophorolipid is prepared as follows: S1. Add sophorolipid, tetrahydrofuran, and 3-(perfluorohexyl)propane oxide to the reactor, stir, and heat to maintain the temperature for reaction; S2. Add deionized water and sodium 2-chloroethylsulfonate to the above reactor, stir, heat and keep the reaction at a constant temperature of 7-8 to obtain modified sophorolipid.

[0008] The structural formula of the lauryl alcohol polyoxyethylene ether is as follows:

[0009] Its average molecular weight is 1200.

[0010] The structural formulas of the main components of the modified sophorolipid are as follows: , Furthermore, R is one of H, a, and b.

[0011] Furthermore, the structural formulas for a and b are as follows: , , The second objective of this invention is to provide a method for preparing the above-mentioned biological anti-wax agent, the preparation method specifically comprising the following steps: S1. In the first reactor, add sophorolipid, tetrahydrofuran, and 3-(perfluorohexyl)propane oxide, stir, and heat to maintain the temperature for reaction; S2. Add deionized water and sodium 2-chloroethylsulfonate to the above reactor, stir, heat and keep the reaction at a constant temperature, maintaining pH 7-8, to obtain modified sophorolipid; S3. Water, modified sophorolipid, and lauryl alcohol polyoxyethylene ether are added sequentially to the second reactor and stirred evenly to obtain a biological wax remover.

[0012] In this invention, the mass ratio of 3-(perfluorohexyl)propane oxide, sodium 2-chloroethylsulfonate, and sophorolipid is further 0.2-0.5:0.1-0.2:1.

[0013] Furthermore, the mass ratio of tetrahydrofuran, deionized water, and sophorolipid is 6-8:4-6:1.

[0014] Furthermore, the heating and heat preservation reaction described in S1 is carried out at a temperature of 60-70°C for a time of 6-12 hours.

[0015] Furthermore, the heating and heat preservation reaction temperature described in S2 is 80-90℃ and the time is 4-6h.

[0016] A third objective of this invention is to provide the application of the above-mentioned biological wax remover in high-wax crude oil.

[0017] The bio-dewaxing agent of this invention is a mixed solution of a modified biosurfactant (modified sophorolipid) and another biosurfactant (lauryl alcohol polyoxyethylene ether). Sophorolipid can significantly reduce the oil-water interfacial tension, emulsifying crude oil into stable small oil droplets. Wax crystals are unlikely to aggregate into large particles and adhere to the pipe wall. It can also adsorb onto the surface of growing wax crystals, changing their crystal morphology and growth direction, resulting in smaller, more regular shapes rather than large, interconnected crystals, thus reducing the possibility of wax deposition. Furthermore, the modified sophorolipid incorporates fluorinated lipophilic groups, possessing extremely low surface energy and strong hydrophobic and oleophobic properties, forming a non-stick layer on the metal surface to prevent wax adsorption and deposition. The introduction of sulfonates alters the wettability and polarity of wax crystals, preventing their aggregation and growth, while simultaneously reducing the oil-water interfacial tension, promoting the emulsification and dispersion of wax deposits in the crude oil, thereby achieving a dual effect of preventing and removing wax. Lauryl alcohol polyoxyethylene ether primarily inhibits wax deposition by reducing the interfacial tension between oil and water, emulsifying and dispersing wax crystals, and preventing their aggregation and deposition. Simultaneously, it adsorbs onto the pipe surface to form a hydrophilic film, preventing wax crystal adhesion and thus effectively suppressing wax deposition. Tetrahydrofuran in the mixed solution can effectively dissolve and remove deposited paraffin wax and significantly enhance the dissolving ability of biosurfactants on paraffin wax.

[0018] The beneficial effects and advantages of this invention compared with the prior art are as follows: (1) The biological wax remover of the present invention does not produce by-products during the preparation process, and the product does not require purification, which is an environmentally friendly production method; (2) The biological wax remover of the present invention has a good wax removal effect, and the wax dissolving rate can reach up to 0.091 g / min; (3) The biological anti-wax agent of the present invention has a good anti-wax effect, and the anti-wax rate can reach up to 98%. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein. Example 1

[0020] S1. In the reactor, add 20g sophorolipid, 150g tetrahydrofuran, and 4g 3-(perfluorohexyl)propane oxide, stir, and keep the temperature at 60℃ for 12h. S2. Add 110g of deionized water and 2g of sodium 2-chloroethylsulfonate to the above reactor, stir, keep the reaction at 80℃ for 5h, and maintain pH 7-8 to obtain modified sophorolipid G1. Example 2

[0021] S1. In the reactor, add 20g sophorolipid, 135g tetrahydrofuran, and 6g 3-(perfluorohexyl)propane oxide, stir, and keep the temperature at 65℃ for 10h. S2. Add 90g of deionized water and 4g of sodium 2-chloroethyl sulfonate to the above reactor, stir, keep the reaction at 90℃ for 4h, maintain pH 7-8, and obtain modified sophorolipid G2. Example 3

[0022] S1. In the reactor, add 20g sophorolipid, 140g tetrahydrofuran, and 8g 3-(perfluorohexyl)propane oxide, stir, and keep the temperature at 70℃ for 6 hours. S2. Add 103g of deionized water and 4g of sodium 2-chloroethylsulfonate to the above reactor, stir, keep the reaction at 85℃ for 6h, maintain pH 7-8, and obtain modified sophorolipid G3. Example 4

[0023] S1. In the reactor, add 20g sophorolipid, 120g tetrahydrofuran, and 10g 3-(perfluorohexyl)propane oxide, stir, and keep the temperature at 65℃ for 8 hours. S2. Add 120g of deionized water and 3g of sodium 2-chloroethylsulfonate to the above reactor, stir, keep the reaction at 88℃ for 5h, and maintain pH 7-8 to obtain modified sophorolipid G4. Example 5

[0024] S1. In the reactor, add 20g sophorolipid, 160g tetrahydrofuran, and 10g 3-(perfluorohexyl)propane oxide, stir, and keep the temperature at 68℃ for 8 hours. S2. Add 80g of deionized water and 3g of sodium 2-chloroethyl sulfonate to the above reactor, stir, keep the reaction at 90℃ for 6h, maintain pH 7-8, and obtain modified sophorolipid G5. Example 6

[0025] 94.5g of water, 5g of G1, and 0.5g of lauryl alcohol polyoxyethylene ether were added sequentially to the reactor and stirred until homogeneous to obtain a biological wax inhibitor. Example 7

[0026] 92g of water, 7g of G2, and 1g of lauryl alcohol polyoxyethylene ether were added to the reactor in sequence and stirred until homogeneous to obtain a biological wax inhibitor. Example 8

[0027] 90g of water, 9g of G3, and 1g of lauryl alcohol polyoxyethylene ether were added sequentially to the reactor and stirred until homogeneous to obtain a biological wax inhibitor. Example 9

[0028] 89.2g of water, 10g of G4, and 0.8g of lauryl alcohol polyoxyethylene ether were added sequentially to the reactor and stirred until homogeneous to obtain a biological wax inhibitor. Example 10

[0029] 91.3g of water, 8g of G5, and 0.7g of lauryl alcohol polyoxyethylene ether were added sequentially to the reactor and stirred until homogeneous to obtain a biological wax inhibitor. Example 11

[0030] According to Example 1, various substances were mixed, namely, 20g of sophorolipid, 150g of tetrahydrofuran, 4g of 3-(perfluorohexyl)propane oxide, 110g of deionized water, and 2g of sodium 2-chloroethylsulfonate were added to a reactor and stirred to obtain D1.

[0031] Comparative Example 1 The preparation method is the same as in Example 6, except that D1 is used instead of G1.

[0032] Comparative Example 2 The preparation method is the same as in Example 6, except that the amount of water added is 95g and lauryl alcohol polyoxyethylene ether is not added.

[0033] Comparative Example 3 The preparation method is the same as in Example 6, except that the amount of water added is 99.5g and G1 is not added.

[0034] Test Example 1: Test of Wax Melting Rate Referring to SY / T 6300-2009 "General Technical Conditions for Wax Removal and Prevention Agents for Oil Production", the wax dissolution rate of Examples 6-10 and Comparative Examples 1-3 of this invention was tested, and the test results are shown in Table 1.

[0035] Test Example 2: Wax Resistance Test Examples 6-10 and Comparative Examples 1-3 of this invention were diluted with anhydrous ethanol to a concentration of 10 wt%. The wax prevention rate was tested with reference to SY / T6300-2009 "General Technical Conditions for Dewaxing and Anti-waxing Agents for Oil Production". The crude oil used for the test was taken from a joint station of Shengli Oilfield with a water content of 50.5%. The test results are shown in Table 1.

[0036] Table 1 Results of wax dissolution and wax prevention tests

[0037] Comparative Example 1 and Example 6 show that the modified sophorolipid has a better wax-removing and wax-preventing effect than sophorolipid itself. The wax-removing and wax-preventing performance is improved by a chemical reaction between sophorolipid and 3-(perfluorohexyl)propane oxide and sodium 2-chloroethylsulfonate, rather than by a simple compounding. The modified sophorolipid solution plays a significant role in the wax-removing and wax-preventing effect. Laureth polyoxyethylene ether also plays a certain role in the wax-removing and wax-preventing effect.

[0038] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A biological wax remover, characterized in that, The aforementioned biological wax remover, by weight percentage, is composed of the following raw materials: Modified sophorolipids 5-10%; Laureth polyoxyethylene ether 0.5-1%; Water balance; The modified sophorolipid is prepared as follows: S1. Add sophorolipid, tetrahydrofuran, and 3-(perfluorohexyl)propane oxide to the reactor, stir, and heat to maintain the temperature for reaction; S2. Add deionized water and sodium 2-chloroethylsulfonate to the above reactor, stir, heat and keep the reaction at a constant temperature, maintaining pH 7-8, to obtain modified sophorolipid; The structural formula of the lauryl alcohol polyoxyethylene ether is as follows: ， Its average molecular weight is 1200.

2. The biological wax remover according to claim 1, characterized in that, The structural formulas of the main components of the modified sophorolipid are as follows: ， The R mentioned is one of H, a, and b; Wherein, the structural formulas a and b are respectively: 、 。 3. The preparation method of the biological anti-wax agent according to claim 1, characterized in that, The preparation method specifically includes the following steps: S1. In the first reactor, add sophorolipid, tetrahydrofuran, and 3-(perfluorohexyl)propane oxide, stir, and heat to maintain the temperature for reaction; S2. Add deionized water and sodium 2-chloroethylsulfonate to the above reactor, stir, heat and keep the reaction at a constant temperature, maintaining pH 7-8, to obtain modified sophorolipid; S3. Water, modified sophorolipid, and lauryl alcohol polyoxyethylene ether are added sequentially to the second reactor and stirred evenly to obtain a biological wax remover. The mass ratio of 3-(perfluorohexyl)propane oxide, sodium 2-chloroethylsulfonate, and sophorolipid is 0.2-0.5:0.1-0.2:

1.

4. The method for preparing the biological anti-wax agent according to claim 3, characterized in that, The mass ratio of tetrahydrofuran, deionized water and sophorolipid is 6-8:4-6:

1.

5. The method for preparing the biological anti-wax agent according to claim 3, characterized in that, The heating and heat preservation reaction described in S1 is carried out at a temperature of 60-70℃ for 6-12 hours.

6. The method for preparing the biological anti-wax agent according to claim 3, characterized in that, The heating and heat preservation reaction temperature described in S2 is 80-90℃, and the time is 4-6h.

7. The application of the biological wax-removing agent according to claim 1 or 2 in high-wax crude oil.

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