Oil field paraffin remover and preparation method thereof

Abstract

The present application belongs to the technical field of oil exploitation, and particularly relates to an oilfield wax cleaning and preventing agent and a preparation method thereof. The wax cleaning and preventing agent is composed of the following raw materials in percentage by weight: mixed surfactant, 10-15%; fatty alcohol polyoxyethylene ether (AEO-9), 0.5-1%; fast penetrating agent T, 0.5-1%; and water; the rest is water; the preparation method of the mixed surfactant is as follows: adding mixed solvent, hexafluorobisphenol A and stirring uniformly in a reactor, adding epoxy bromopropane; slowly adding sodium hydroxide in batches, controlling the pH to be 8-9, adding 3-amino-1,5-naphthalene disulfonic acid disodium salt, controlling the pH to be 8-9, adding 1-amino-3,6,9,12,15,18-hexaoxaheneicosan-21-oic acid, controlling the pH to be 8-9, and obtaining the mixed surfactant. The wax cleaning and preventing agent has the advantages of environmental protection in the preparation process and good wax cleaning and preventing effect.

Description

Technical Field

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

[0002] Over 80% of the crude oil produced in my country is waxy crude oil, with wax content ranging from 10% to 50%. Crude oil with a wax content exceeding 10% accounts for 90% of the total extracted oil. During crude oil extraction, as crude oil rises from the formation to the surface, the temperature and pressure in the wellbore gradually decrease. When the wax precipitation point is reached, paraffin wax begins to crystallize and precipitate, adhering to the inner wall of the tubing, sucker rod, and the surface of downhole equipment. Wax deposition reduces the effective inner diameter of the oil flow channel, increases flow resistance, and consequently reduces oil well production. In severe cases, it can cause wax blockage, production shutdown, or even downhole accidents. Furthermore, wax deposition accelerates equipment wear, increases the frequency of well workovers and maintenance, and causes significant economic losses to normal oilfield production.

[0003] Currently, the commonly used wax removal and prevention methods in oilfields mainly fall into three categories: mechanical wax removal, thermal wax removal, and chemical wax removal. Mechanical wax removal physically removes the wax layer using a wax scraper, while thermal wax removal melts the wax through heating. However, both require well shutdown, resulting in high labor intensity and energy consumption, and thermal wax removal can easily cause formation contamination. New technologies such as acoustic and microbial methods have high requirements for equipment and operation, making large-scale promotion difficult. In contrast, chemical wax removal and prevention do not require well shutdown, are convenient to operate, and have good results, gradually becoming the dominant technology.

[0004] Chemical wax removers and inhibitors are classified into three categories: oil-based, water-based, and emulsion-type. Oil-based wax removers have a strong ability to dissolve wax, but are toxic and flammable; water-based wax removers are environmentally friendly and safe, but have poor wax removal and inhibitory effects; emulsion-type wax removers, through the emulsification of oil and water phases by surfactants, combine good wax removal effects with environmental safety, making them a research hotspot. Wax removers and inhibitors typically consist of surfactants, solvents, wax crystal inhibitors, and dispersants. Surfactants can reduce interfacial tension, disrupt wax crystal aggregation, and enhance dissolution ability. Nonionic surfactants are widely used in emulsion-type products and can effectively improve wax removal and inhibitory performance. However, existing products suffer from problems such as single function, strong selectivity, and limited applicable temperature range, making it difficult to meet the needs of complex working conditions. Therefore, developing novel wax removers and inhibitors with synergistic functions, strong adaptability, and stable performance is of great significance. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides an oilfield wax remover and preservative agent and its preparation method. The wax remover and preservative agent of this invention has an environmentally friendly preparation process and excellent wax removal and preservative effects.

[0006] The first objective of this invention discloses an oilfield wax remover and preservative, which, by weight percentage, is composed of the following raw materials: Mixed surfactants 10-15%; Fatty alcohol polyoxyethylene ether (AEO-9) 0.5-1%; Rapid penetration agent T 0.5-1%; Water balance; The preparation method of the hybrid surfactant is as follows: (1) Add mixed solvent and hexafluorobisphenol A to the reactor, stir evenly, and add epichlorohydrin; (2) Add sodium hydroxide slowly in batches, keep the reaction warm, and control the pH to 8-9; (3) Add disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the reaction warm, and control the pH to 8-9; (4) Add 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the reaction at a constant temperature, and control the pH to 8-9 to obtain a mixed surfactant.

[0007] The second objective of this invention is to provide a method for preparing the above-mentioned wax-removing agent, the method specifically comprising the following steps: (1) Add mixed solvent and hexafluorobisphenol A to the first reactor, stir until uniform, and add epichlorohydrin; (2) Add sodium hydroxide slowly in batches, keep the reaction warm, and control the pH to 8-9; (3) Add disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the reaction warm, and control the pH to 8-9; (4) Add 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the reaction at a constant temperature, and control the pH to 8-9 to obtain a mixed surfactant; (5) Add the mixed surfactant solution, fatty alcohol polyoxyethylene ether (AEO-9), fast penetrant T and water to the second reactor in sequence, and stir until uniform to obtain the wax remover.

[0008] In this invention, preferably, the molar ratio of epichlorohydrin, disodium 3-amino-1,5-naphthalenedisulfonic acid, 1-amino-3,6,9,12,15,18-hexaoxane-21-acid to hexafluorobisphenol A is 1.8-2.5:0.8-1.2:0.8-1.2:1.

[0009] Preferably, the mixed solvent is a mixture of methanol and ethanol in a ratio of 1:1 (V:V), and the mass ratio of the mixed solvent to bisphenol A is 30-35:1.

[0010] Preferably, in step (2), the heat preservation reaction temperature is 40-60℃ and the time is 2-4h.

[0011] Preferably, in step (3), the heat preservation reaction temperature is 40-60℃ and the time is 6-12h.

[0012] Preferably, in step (4), the heat preservation reaction temperature is 60-80℃ and the time is 2-4h.

[0013] The structural formulas of the main components in the aforementioned mixed surfactant are as follows:

[0014] The wax-removing agent of this invention is formulated from a mixed surfactant solution, fatty alcohol polyoxyethylene ether (AEO-9), a fast penetrant T, and water. The mixed surfactant solution can wet and reverse the wax reaction, reduce interfacial tension, penetrate wax crystal gaps, and disperse wax molecules. The methanol and ethanol in the solution can solubilize the wax and improve the miscibility between water and the wax. The fatty alcohol polyoxyethylene ether (AEO-9) can rapidly emulsify and disperse the detached wax into tiny particles, preventing redeposition. The fast penetrant T has a double-tailed chain structure and extremely fast penetration speed, allowing it to quickly insert between the wax and the substrate, weakening the wax-tube wall adhesion and making the wax easier to remove.

[0015] The beneficial effects and advantages of this invention compared with the prior art are as follows: (1) The wax remover of the present invention produces no byproducts during the preparation process, and is an environmentally friendly production method; (2) The 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 wax-removing agent of the present invention has a good wax-removing effect, and the wax-removing rate can reach up to 96%. Detailed Implementation

[0016] 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.

[0017] The technical solution of the present invention will be further described below with reference to specific embodiments: Example 1

[0018] (1) Add 202g of methanol and ethanol mixed solvent (V:V=1:1), 20mmol of hexafluorobisphenol A to the reactor, stir well, and add 36mmol of epichlorohydrin. (2) Add sodium hydroxide slowly in batches, keep the temperature at 40℃ for 4 hours, and control the pH to 8-9; (3) Add 16 mmol of disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the temperature at 40℃ for 12 h, and control the pH to 8-9; (4) Add 16 mmol of 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the temperature at 60℃ for 4 h, control the pH to 8-9, and obtain a mixed surfactant solution H1. Example 2

[0019] (1) Add 214g of methanol and ethanol mixed solvent (V:V=1:1), 20mmol of hexafluorobisphenol A to the reactor, stir evenly, and add 50mmol of epichlorohydrin. (2) Add sodium hydroxide slowly in batches, keep the temperature at 50°C for 3 hours, and control the pH to 8-9; (3) Add 24 mmol of disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the temperature at 45℃ for 8 h, and control the pH to 8-9; (4) Add 22 mmol of 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the temperature at 70℃ for 4 h, control the pH to 8-9, and obtain a mixed surfactant solution H2. Example 3

[0020] (1) Add 223g of methanol and ethanol mixed solvent (V:V=1:1), 20mmol of hexafluorobisphenol A to the reactor, stir well, and add 40mmol of epichlorohydrin. (2) Add sodium hydroxide slowly in batches, keep the temperature at 60℃ for 2 hours, and control the pH to 8-9; (3) Add 18 mmol of disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the reaction at 55℃ for 8 h, and control the pH to 8-9; (4) Add 24 mmol of 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the temperature at 80℃ for 2 h, control the pH to 8-9, and obtain a mixed surfactant solution H3. Example 4

[0021] (1) Add 230g of methanol and ethanol mixed solvent (V:V=1:1), 20mmol of hexafluorobisphenol A to the reactor, stir well, and add 44mmol of epichlorohydrin. (2) Add sodium hydroxide slowly in batches, keep the temperature at 50°C for 3 hours, and control the pH to 8-9; (3) Add 20 mmol of disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the temperature at 60℃ for 6 h, and control the pH to 8-9; (4) Add 18 mmol of 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the temperature at 70℃ for 3 h, control the pH to 8-9, and obtain a mixed surfactant solution H4. Example 5

[0022] (1) Add 235g of methanol and ethanol mixed solvent (V:V=1:1), 20mmol of hexafluorobisphenol A to the reactor, stir well, and add 46mmol of epichlorohydrin. (2) Add sodium hydroxide slowly in batches, keep the reaction at 55℃ for 4 hours, and control the pH to 8-9; (3) Add 22 mmol of disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the temperature at 50℃ for 10 h, and control the pH to 8-9; (4) Add 20 mmol of 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the temperature at 75℃ for 3 h, control the pH to 8-9, and obtain a mixed surfactant solution H5. Example 6

[0023] 10g H1, 0.5g AEO-9, 0.5g rapid penetrant T, and 89g water were added sequentially to the reactor and stirred until homogeneous to obtain a wax-removing agent. Example 7

[0024] 12g H2, 1g AEO-9, 0.5g rapid penetrant T, and 86.5g water were added sequentially to the reactor and stirred until homogeneous to obtain a wax-removing agent. Example 8

[0025] 13g H3, 0.5g AEO-9, 1g rapid penetrant T, and 85.5g water were added sequentially to the reactor and stirred until homogeneous to obtain a wax-removing agent. Example 9

[0026] 14g H4, 0.7g AEO-9, 0.7g rapid penetrant T, and 84.6g water were added sequentially to the reactor and stirred until homogeneous to obtain a wax-removing agent. Example 10

[0027] 15g H5, 0.8g AEO-9, 0.6g rapid penetrant T, and 83.6g water were added sequentially to the reactor and stirred until homogeneous to obtain a wax-removing agent.

[0028] Comparative Example 1 The preparation process is the same as in Example 6, except that H1 is not added and the amount of water added is 99g.

[0029] Comparative Example 2 The preparation process is the same as in Example 6, except that AEO-9 is not added and the amount of water added is 89.5g.

[0030] Comparative Example 3 The preparation process is the same as in Example 6, except that the rapid penetration agent T is not added and the amount of water added is 89.5g.

[0031] 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 was tested, and the test results are shown in Table 1.

[0032] Test Example 2: Wax Resistance Test Examples 6-10 and Comparative Examples 1-3 were diluted with anhydrous ethanol to a concentration of 10 wt%. The wax prevention rate was tested with reference to SY / T 6300-2009 "General Technical Conditions for Wax Removal and Inhibition Agents for Oil Production". The crude oil used for the test was heavy oil from an oil production plant in Shengli Oilfield with a water content of 54.6%. The test results are shown in Table 1.

[0033] Table 1 Test results of wax removal and prevention

[0034] As can be seen from Table 1: Compared with Example 6, Comparative Example 1 showed a decrease in the wax dissolution rate of 0.046 g / min and a decrease in the wax prevention rate of 41%, indicating that the mixed surfactant solution played a major role in wax removal and prevention. Compared with Example 6, Comparative Example 2 showed a decrease in the wax dissolution rate of 0.01 g / min and a decrease in the wax prevention rate of 10%, indicating that AEO-9 played a significant role in wax removal and prevention. Compared with Example 6, Comparative Example 3 showed a decrease in the wax dissolution rate of 0.015 g / min and a decrease in the wax prevention rate of 9%, indicating that the fast penetrant T played a significant role in wax removal and prevention.

[0035] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. An oilfield wax remover and preservative, characterized in that, The aforementioned wax remover, by weight percentage, is composed of the following raw materials: Mixed surfactants 10-15%; Fatty alcohol polyoxyethylene ether (AEO-9) 0.5-1%; Rapid penetration agent T 0.5-1%; Water balance; The preparation method of the hybrid surfactant is as follows: (1) Add mixed solvent and hexafluorobisphenol A to the reactor, stir evenly, and add epichlorohydrin; (2) Add sodium hydroxide slowly in batches, keep the reaction warm, and control the pH to 8-9; (3) Add disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the reaction warm, and control the pH to 8-9; (4) Add 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the reaction at a constant temperature, and control the pH to 8-9 to obtain a mixed surfactant.

2. The method for preparing the wax-removing agent according to claim 1, characterized in that, The preparation method specifically includes the following steps: (1) Add mixed solvent and hexafluorobisphenol A to the first reactor, stir until uniform, and add epichlorohydrin; (2) Add sodium hydroxide slowly in batches, keep the reaction warm, and control the pH to 8-9; (3) Add disodium 3-amino-1,5-naphthalenedisulfonic acid, keep the reaction warm, and control the pH to 8-9; (4) Add 1-amino-3,6,9,12,15,18-hexaoxane-21-acid, keep the reaction at a constant temperature, and control the pH to 8-9 to obtain a mixed surfactant; (5) Add the mixed surfactant solution, fatty alcohol polyoxyethylene ether (AEO-9), fast penetrant T and water to the second reactor in sequence, and stir until uniform to obtain the wax remover; The molar ratio of the aforementioned epichlorohydrin, disodium 3-amino-1,5-naphthalenedisulfonic acid, 1-amino-3,6,9,12,15,18-hexaoxane-21-acid to hexafluorobisphenol A is 1.8-2.5:0.8-1.2:0.8-1.2:

1.

3. The preparation method according to claim 2, characterized in that, The mixed solvent is a mixture of methanol and ethanol in a ratio of 1:1 (V:V), and the mass ratio of it to hexafluorobisphenol A is 30-35:

1.

4. The preparation method according to claim 2, characterized in that, In step (2), the heat preservation reaction temperature is 40-60℃ and the time is 2-4h.

5. The preparation method according to claim 2, characterized in that, In step (3), the heat preservation reaction temperature is 40-60℃ and the time is 6-12h.

6. The preparation method according to claim 2, characterized in that, In step (4), the heat preservation reaction temperature is 60-80℃ and the time is 2-4h.

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