Paraffin remover and inhibitor as well as preparation method and application thereof

Abstract

The invention provides a paraffin remover and inhibitor as well as a preparation method and application thereof. The paraffin remover and inhibitor comprises the following components in parts by weight: 60-80 parts of a solvent, 10-20 parts of an asphalt dispersant, 5-15 parts of a pour point depressing synergist, 2-8 parts of a solubilizer and 2-5 parts of a first surfactant, wherein the solvent comprises an N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil with the density being greater than 0.979 g / cm < 3 > at the temperature of 20 DEG C and light solvent oil with the density being 0.66-0.76 g / cm < 3 > at the temperature of 20 DEG C. The paraffin removal and inhibition agent can effectively dissolve complex-component high-carbon-number wax formed by long-term deposition on the inner wall of a high-pressure gas well casing, and has important significance in increasing oil and gas channels in a high-pressure gas well, reducing the perforation times of an oil casing and ensuring the integrity of a shaft.

Description

Technical Field

[0001] The invention relates to the technical field of oil casing wax removal and prevention, and in particular to a wax removal and prevention agent, a preparation method and application thereof. Background Art

[0002] The crude oil produced from most oil fields in my country contains a lot of wax. According to statistics, crude oil with a wax content greater than 10% accounts for more than 90% of the total crude oil output, and most crude oil contains more than 20% wax. The wax content of crude oil produced in some areas even reaches 40-50%. The wax content in high-pressure condensate gas wells in oil fields in northwest my country is also high. As the high-pressure condensate gas flows from the bottom of the well to the wellhead, the temperature gradually decreases. When the temperature is lower than the wax precipitation point, the wax crystals in the components will precipitate, gather on the pipe wall, diffuse and stack, and form a thick wax scale layer. The deposited wax scale layer will cause the oil and gas channels to narrow, increase the air flow resistance, and lead to reduced production capacity. In severe cases, it may even cause problems such as oil pipe perforation and oil and gas well shutdown, seriously affecting the integrity of the wellbore.

[0003] At present, the commonly used wax removal and prevention technologies for high-pressure gas wells include mechanical wax removal, thermal wax removal, strong magnetic wax prevention, chemical wax removal and prevention, and microbial wax removal and prevention, etc. Among them, chemical wax removal and prevention technology is widely used in major oil fields because it does not require well shutdown, simple and convenient injection equipment, long action time, no damage to the bottom layer, can remove the wax scale formed on the pipe wall and prevent the further formation of wax scale, etc.

[0004] Chemical wax removal and prevention technology usually uses chemical agents as the components of wax removal and prevention agents, including carbon disulfide, CCl x It has good wax dissolving properties and is used as the main agent of wax removal and prevention agent. However, carbon disulfide and CCl x It will seriously corrode oil and gas pipelines and have an adverse effect on the refining process of crude oil, and has been banned from use. At present, most of the existing wax removal and prevention products on the market have problems such as poor on-site wax dissolution effect, poor stability, and low flash point, especially for the dissolution effect of high carbon number wax precipitated from high-pressure condensate gas wells, so there are defects in wax dissolution rate and wax prevention rate.

[0005] In view of this, this application is hereby filed. Summary of the invention

[0006] The main purpose of the present invention is to provide a wax removal and prevention agent, a preparation method and application thereof, so as to solve the problem that the wax removal and prevention agent products in the prior art have insufficient wax dissolution rate and wax prevention rate and are not suitable for high-pressure gas well wax removal and prevention treatment.

[0007] In order to achieve the above-mentioned object, according to one aspect of the present invention, a wax removal and prevention agent is provided, which comprises, by weight, 60 to 80 parts of a solvent, 10 to 20 parts of an asphalt dispersant, 5 to 15 parts of a pour point depressant synergist, 2 to 8 parts of a solubilizing agent and 2 to 5 parts of a first surfactant; wherein the solvent comprises N-methylmaleimide-styrene copolymer, xylene, a 20°C density greater than 0.979 g / cm 3 Heavy aromatic solvent oil and density at 20℃ is 0.66~0.76g / cm 3 Light solvent oil.

[0008] Furthermore, the N-methylmaleimide-styrene copolymer is obtained by suspension polymerization of N-methylmaleimide and styrene; preferably, the suspension polymerization is carried out with ethanol as solvent and under the action of a peroxide initiator; more preferably, the suspension polymerization temperature is 75-80°C.

[0009] Furthermore, the weight ratio of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil and light solvent oil is (10-20):(30-50):(10-20):(20-50).

[0010] Further, the heavy aromatic solvent oil is selected from heavy aromatic solvent oil S1500# and / or heavy aromatic solvent oil S1800#, and the light solvent oil is selected from one or more of solvent oil 6#, solvent oil 90#, solvent oil 120# and solvent oil 200#; more preferably, the heavy aromatic solvent oil is heavy aromatic solvent oil S1500#, and the light solvent oil is solvent oil 200#; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1500#, and the light solvent oil is solvent oil 90#; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1800#, and the light solvent oil is a mixed solvent of solvent oil 90#, solvent oil 120# and solvent oil 200# in a weight ratio of 1:1:1; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1800#, and The light solvent oil is a mixed solvent of solvent oil 90# and solvent oil 120# in a weight ratio of 3:1; preferably, the pour point depressant and enhancer is a mixture of alkylbenzene sulfonic acid and alcoholamine compounds; more preferably, the alkylbenzene sulfonic acid is dodecylbenzene sulfonic acid, and the alcoholamine compounds are ethanolamine and / or isopropanolamine; most preferably, the pour point depressant and enhancer is a mixture of dodecylbenzene sulfonic acid, ethanolamine and isopropanolamine in a weight ratio of (2.8-3.2):(1.8-2.2):1; preferably, the solubilizer is alkylbenzene sulfonic acid, more preferably sodium dodecylbenzene sulfonate; preferably, the first surfactant is propylene glycol fatty acid ester and / or propylene glycol monolaurate, more preferably a mixture of propylene glycol fatty acid ester and propylene glycol monolaurate in a weight ratio of (1-2):(1-3).

[0011] Furthermore, the asphalt dispersant includes a dispersant main agent, a second surfactant and a dispersant solvent, wherein the dispersant main agent is a polyisobutylene succinic anhydride derivative; preferably, the polyisobutylene succinic anhydride derivative is an esterification reaction product of polyisobutylene succinic anhydride and 3-(3-hydroxypropyl)phenol.

[0012] Furthermore, the polyisobutylene succinic anhydride derivative is prepared by the following preparation method: step S1, reacting isobutylene and maleic anhydride crystals at a temperature of 180±5°C for 2 to 2.5 hours, then adding an excessive amount of maleic anhydride to the reaction system, and adjusting the temperature to 230±5°C to continue the reaction for 3.5 to 4.5 hours, so that the degree of substitution of maleic anhydride on polyisobutylene is greater than 1.2, to obtain polyisobutylene succinic anhydride; step S2, reacting polyisobutylene succinic anhydride and 3-(3-hydroxy)-1,1-diol; Preferably, in step S1, after the maleic anhydride is excessively added and the reaction is continued, the product system is dissolved with n-heptane to remove the unreacted maleic anhydride, and then the polyisobutylene succinic anhydride is obtained by vacuum distillation; preferably, in step S2, after the reaction is completed, the reaction system is cooled, washed, filtered and dried in sequence to obtain the polyisobutylene succinic anhydride.

[0013] Furthermore, the second surfactant is selected from polyoxyethylene alkylphenol and / or polyoxyethylene octylphenyl ether, and the dispersant solvent is selected from NN dimethylformamide; preferably, the weight content of the second surfactant in the asphalt dispersant is 1 to 3%, and the weight content of the dispersant solvent in the asphalt dispersant is 50 to 70%.

[0014] According to another aspect of the present invention, a method for preparing the above-mentioned wax removal and prevention agent is also provided, which comprises the following steps: mixing and dispersing a solvent, an asphalt dispersant, a pour point depressant synergist, a solubilizer and a first surfactant according to a ratio to obtain a wax removal and prevention agent; wherein the solvent comprises N-methylmaleimide-styrene copolymer, xylene, and a density greater than 0.979 g / cm at 20°C. 3 Heavy aromatic solvent oil and density at 20℃ is 0.66~0.76g / cm 3 Light solvent oil.

[0015] Furthermore, the above-mentioned preparation method includes the following steps: mixing xylene, heavy aromatic solvent oil and light solvent oil and stirring; under stirring, sequentially adding N-methylmaleimide-styrene copolymer, a first surfactant, a solubilizer and a pour point depressant synergist to the system; under stirring, further adding an asphalt dispersant to the system to obtain a wax removal and prevention agent; preferably, before adding the asphalt dispersant, the dispersant main agent, the second surfactant and the dispersant solvent are pre-mixed to prepare the asphalt dispersant.

[0016] According to another aspect of the present invention, there is also provided a use of the above-mentioned wax removing and preventing agent as a wax removing and preventing agent for high-pressure gas well casing.

[0017] The wax removal and prevention agent provided by the present invention does not contain carbon disulfide and organic chlorine, has a closed cup flash point of more than 35°C, and a density of 0.96 g / cm 3 . According to the test of SY / T 6300 standard, the wax removal and wax prevention agent has a high wax dissolution rate and wax prevention rate. The wax dissolution rate can reach up to 0.043g / min, the wax prevention rate can even reach 43.6%, and the viscosity reduction rate can even reach 52.1%. The wax removal and wax prevention agent can effectively dissolve the complex high carbon number wax formed by long-term deposition on the inner wall of the high-pressure gas well casing, which is of great significance in increasing oil and gas channels in high-pressure gas wells, reducing the number of oil casing perforations, and ensuring the integrity of the wellbore. DETAILED DESCRIPTION

[0018] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0019] As described in the background technology section, most of the existing wax removal and prevention products on the market have problems such as poor on-site wax dissolving effect, poor stability, and low flash point, especially poor dissolving effect on high carbon number wax precipitated from high-pressure condensate gas wells, and thus have defects in wax dissolving rate and wax prevention rate. In order to solve this problem, the present invention provides a wax removal and prevention agent, which does not contain carbon disulfide and organic chlorine, has a closed cup flash point of more than 35°C, and a density of 0.96g / cm 3 . According to the test of SY / T 6300 standard, the wax removal and wax prevention agent has a high wax dissolution rate and wax prevention rate. The wax dissolution rate can reach up to 0.043g / min, the wax prevention rate can even reach 43.6%, and the viscosity reduction rate can even reach 52.1%. The wax removal and wax prevention agent can effectively dissolve the complex high carbon number wax formed by long-term deposition on the inner wall of the high-pressure gas well casing, which is of great significance in increasing oil and gas channels in high-pressure gas wells, reducing the number of oil casing perforations, and ensuring the integrity of the wellbore.

[0020] In a typical embodiment, the paraffin removal and prevention agent is characterized in that, by weight, the paraffin removal and prevention agent includes 60 to 80 parts of a solvent, 10 to 20 parts of an asphalt dispersant, 5 to 15 parts of a pour point depressant synergist, 2 to 8 parts of a solubilizer and 2 to 5 parts of a first surfactant; wherein the solvent includes N-methylmaleimide-styrene copolymer, xylene, and a 20°C density greater than 0.979 g / cm 3 Heavy aromatic solvent oil and density at 20℃ is 0.66~0.76g / cm 3 Light solvent oil.

[0021] N-methylmaleimide-styrene copolymer has a good dissolving effect on high carbon number wax (carbon content greater than 40) in wax samples. Heavy aromatic solvent oil has a poor effect when used alone, but after being added to the wax removal and prevention agent system of the present invention, the density and flash point of the wax removal and prevention agent product can be improved, while xylene and solvent oil ensure the solubility of the wax removal and prevention agent. At the same time, the high carbon number wax formed by long-term deposition on the inner wall of the high-pressure gas well casing in the oil field is mainly composed of wax, asphaltene and colloid. The addition of asphalt dispersant can effectively disperse the asphaltene in the high carbon number wax, so that paraffin can be dispersed from large pieces into small pieces, accelerating the dissolution rate of paraffin. . The combination of the above-mentioned proportions of the pour point depressant, the solubilizer and the first surfactant can effectively dissolve the complex high carbon number wax formed by long-term deposition on the inner wall of the high-pressure gas well casing, and has a higher wax dissolution rate and wax prevention rate.

[0022] In a preferred embodiment, N-methylmaleimide-styrene copolymer is obtained by suspension polymerization of N-methylmaleimide and styrene. The N-methylmaleimide-styrene copolymer obtained by suspension polymerization has a more suitable molecular weight, and has a better dissolving effect on high carbon number waxes when applied to wax removal and anti-wax agent products. Preferably, the suspension polymerization is carried out with ethanol as solvent under the action of a peroxide initiator (such as dibenzoyl peroxide); more preferably, the temperature of the suspension polymerization is 75 to 80°C. Under the above-mentioned polymerization conditions, the copolymerization reaction is more stable and controllable. In the specific operation process, the crude product obtained by the polymerization reaction is washed with propanol, filtered and dried under vacuum conditions at 50°C to obtain a yellow powder, which is the finished product of N-methylmaleimide-styrene copolymer.

[0023] Taking into account comprehensive properties such as solubility and flash point, in a preferred embodiment, the weight ratio of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil and light solvent oil is (10-20):(30-50):(10-20):(20-50).

[0024] As mentioned above, the addition of heavy aromatic solvent oil is to increase the flash point of the paraffin removal and prevention agent, thereby improving the stability and safety after being applied to high-pressure gas wells. The use of light solvent oil is to cooperate with xylene to achieve a better wax dissolving effect, so as to adapt to the complex composition of paraffin wax removal and prevention in high-pressure gas wells. In order to better play the above-mentioned role, in a preferred embodiment, the heavy aromatic solvent oil is selected from heavy aromatic solvent oil S1500# and / or heavy aromatic solvent oil S1800#, and the light solvent oil is selected from one or more of solvent oil 6#, solvent oil 90#, solvent oil 120# and solvent oil 200#; more preferably, the heavy aromatic solvent oil is heavy aromatic solvent oil S1500#, and the light solvent oil is solvent oil 200#; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1500#, and the light solvent oil is solvent oil 90#; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1800#, and the light solvent oil is a mixed solvent of solvent oil 90#, solvent oil 120# and solvent oil 200# in a weight ratio of 1:1:1; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1800#, and the light solvent oil is a mixed solvent of solvent oil 90# and solvent oil 120# in a weight ratio of 3:1. The use of the above types of heavy aromatic solvent oil and light solvent oil has a better synergistic effect.

[0025] Preferably, the pour point depressant is a mixture of alkylbenzene sulfonic acid and alcoholamine compounds. The above-mentioned pour point depressant can not only form a eutectic and adsorption effect with paraffin in crude oil, change the shape and size of wax crystals, and prevent paraffin from forming a three-dimensional network structure, but also reduce the pour point and viscosity of crude oil and improve the low-temperature fluidity of crude oil. In particular, the two types of compounds are used in combination for better results. More preferably, the alkylbenzene sulfonic acid is dodecylbenzene sulfonic acid, and the alcoholamine compound is ethanolamine and / or isopropanolamine; most preferably, the pour point depressant is a mixture of dodecylbenzene sulfonic acid, ethanolamine and isopropanolamine in a weight ratio of (2.8-3.2):(1.8-2.2):1.

[0026] The wax molecules formed after the surface of the wax ball dissolves will gather around the wax ball to form a high-concentration wax-enriched layer, which prevents the wax removal and prevention agent from contacting the wax ball. Adding a solubilizer can accelerate the diffusion rate of the wax molecules dissolved in the system, increase the contact area between the wax ball and the solvent, and accelerate the dissolution of high-carbon wax. In order to better play the above role, preferably, the solubilizer is alkylbenzene sulfonic acid, more preferably sodium dodecylbenzene sulfonate.

[0027] Preferably, the first surfactant is propylene glycol fatty acid ester and / or propylene glycol monolaurate, more preferably a mixture of propylene glycol fatty acid ester and propylene glycol monolaurate in a weight ratio of (1-2):(1-3). The use of the above surfactants is more conducive to exerting a synergistic effect, further improving the stability of the product, thereby better improving the wax dissolution rate and wax resistance rate.

[0028] In a preferred embodiment, the asphalt dispersant comprises a dispersant main agent, a second surfactant and a dispersant solvent, wherein the dispersant main agent is a polyisobutylene succinic anhydride derivative. The above asphalt dispersant has a better dispersing effect on the asphaltenes in the high carbon number wax, thereby being more conducive to accelerating the dissolution rate of paraffin. Preferably, the polyisobutylene succinic anhydride derivative is an esterification reaction product of polyisobutylene succinic anhydride and 3-(3-hydroxypropyl)phenol.

[0029] Specifically, the polyisobutylene succinic anhydride derivative is prepared by the following preparation method:

[0030] Step S1, reacting isobutylene and maleic anhydride crystals at 180±5°C for 2-2.5h, then adding excess maleic anhydride to the reaction system, and adjusting the temperature to 230±5°C to continue the reaction for 3.5-4.5h, so that the degree of substitution of maleic anhydride on polyisobutylene is greater than 1.2, to obtain polyisobutylene succinic anhydride; Step S2, reacting polyisobutylene succinic anhydride and 3-(3-hydroxypropyl)phenol under the action of a water-carrying agent, The reaction is carried out at a temperature of 160±5°C for 4 to 5 hours to obtain a polyisobutylene succinic anhydride derivative; preferably, in step S1, after the excessive addition of maleic anhydride to continue the reaction, the product system is dissolved with n-heptane to remove the unreacted maleic anhydride, and then subjected to reduced pressure distillation to obtain polyisobutylene succinic anhydride; preferably, in step S2, after the reaction is completed, the reaction system is cooled, washed, filtered, and dried in sequence to obtain a polyisobutylene succinic anhydride derivative. Under the above conditions, the reaction is more stable and controllable, and the obtained polyisobutylene succinic anhydride derivative has better performance.

[0031] Most preferably, the polyisobutylene succinic anhydride derivative is prepared by the following preparation method:

[0032] Step 1: Add a certain amount of isobutylene to a four-necked flask equipped with a thermometer, a reflux condenser and a stirrer, heat to 90°C under nitrogen replacement protection conditions, turn on the stirrer and condensed water, add maleic anhydride crystals in a certain proportion and heat to 180°C to fully react for 2 hours, then add a certain amount of maleic anhydride to make it excessive, raise the temperature to 230°C and continue to react for 4 hours, so that the degree of substitution of maleic anhydride on polyisobutylene is greater than 1.2. After the reaction is completed, add an appropriate amount of n-heptane to dissolve the product, remove excess maleic anhydride, and remove n-heptane by vacuum distillation to obtain polyisobutylene succinic anhydride;

[0033] Step 2: Add a certain amount of polyisobutylene succinic anhydride and 3-(3-hydroxypropyl)phenol in proportion to a four-necked flask equipped with a thermometer, a reflux condenser and a stirrer, turn on the stirrer and condense water, use xylene as a water-carrying agent, heat to 160°C under nitrogen replacement protection conditions to react for 4 hours, cool down and wash with NN dimethylformamide, filter, and dry in an oven at 60°C for 12 hours to obtain a reddish-brown viscous solid, which is a polyisobutylene succinic anhydride derivative. When used, a certain amount of dispersant solvent needs to be added to prepare a solution.

[0034] Preferably, the second surfactant is selected from polyoxyethylene alkylphenol and / or polyoxyethylene octylphenyl ether, and the dispersant solvent is selected from NN dimethylformamide; preferably, the weight content of the second surfactant in the asphalt dispersant is 1-3%, and the weight content of the dispersant solvent in the asphalt dispersant is 50-70%. The above types of second surfactants and dispersant solvents and their usage are more conducive to the asphalt dispersant to function.

[0035] According to another aspect of the present invention, a method for preparing the above-mentioned wax removal and prevention agent is also provided, which comprises the following steps: mixing and dispersing a solvent, an asphalt dispersant, a pour point depressant synergist, a solubilizer and a first surfactant according to a ratio to obtain a wax removal and prevention agent; wherein the solvent comprises N-methylmaleimide-styrene copolymer, xylene, and a density greater than 0.979 g / cm at 20°C. 3 Heavy aromatic solvent oil and density at 20℃ is 0.66~0.76g / cm 3 Solvent naphtha.

[0036] The wax removal and prevention agent prepared by the present invention does not contain carbon disulfide and organic chlorine, has a closed cup flash point of more than 35°C, and a density of 0.96 g / cm 3 . According to the test of SY / T 6300 standard, the wax removal and wax prevention agent has a high wax dissolution rate and wax prevention rate. The wax dissolution rate can reach up to 0.043g / min, the wax prevention rate can even reach 43.6%, and the viscosity reduction rate can even reach 52.1%. The wax removal and wax prevention agent can effectively dissolve the complex high carbon number wax formed by long-term deposition on the inner wall of the high-pressure gas well casing, which is of great significance in increasing oil and gas channels in high-pressure gas wells, reducing the number of oil casing perforations, and ensuring the integrity of the wellbore.

[0037] In order to make the components fully compatible, in a preferred embodiment, the above preparation method includes the following steps: mixing xylene, heavy aromatic solvent oil and light solvent oil and stirring; under stirring, sequentially adding N-methylmaleimide-styrene copolymer, a first surfactant, a solubilizer and a pour point depressant synergist to the system; under stirring, further adding an asphalt dispersant to the system to obtain a paraffin removal and prevention agent; preferably, before adding the asphalt dispersant, the dispersant main agent, the second surfactant and the dispersant solvent are mixed in advance to prepare the asphalt dispersant.

[0038] Specifically, the following method is preferably used to prepare the paraffin removal and prevention agent: first add a solvent composed of xylene, heavy aromatic solvent oil and light solvent oil into a beaker according to a weight ratio, place the beaker on a magnetic stirrer and put in a magnet, turn on the magnetic stirrer and slowly add N-methylmaleimide-styrene copolymer, a first surfactant, a solubilizer and a pour point depressant synergist into the system in turn, stir for 10 minutes to mix them evenly, add the pre-prepared asphalt dispersant into the above system, continue stirring for 30 minutes and then stop, to obtain the paraffin removal and prevention agent for high-pressure gas wells.

[0039] According to another aspect of the present invention, there is also provided a use of the above-mentioned wax removing and preventing agent as a wax removing and preventing agent for high-pressure gas well casing.

[0040] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0041] The preparation of the paraffin removal and prevention agent in the following embodiments all adopts the following method: first, according to the weight ratio, a solvent composed of xylene, heavy aromatic solvent oil and light solvent oil is added into a beaker, the beaker is placed on a magnetic stirrer and a magnet is placed in it, the magnetic stirrer is turned on and N-methylmaleimide-styrene copolymer, a first surfactant, a solubilizer and a pour point depressant synergist are slowly added into the system in turn, and the mixture is stirred for 10 minutes to mix evenly, and the pre-prepared asphalt dispersant is added into the above system, and the stirring is continued for 30 minutes and then stopped to obtain the paraffin removal and prevention agent for high-pressure gas wells.

[0042] The preparation method of asphalt dispersant is as follows:

[0043] Step 1: Add a certain amount of isobutylene to a four-necked flask equipped with a thermometer, a reflux condenser and a stirrer, heat to 90°C under nitrogen replacement protection conditions, turn on the stirrer and condensed water, add maleic anhydride crystals in a certain proportion and heat to 180°C to fully react for 2 hours, then add a certain amount of maleic anhydride to make it excessive, raise the temperature to 230°C and continue to react for 4 hours, so that the degree of substitution of maleic anhydride on polyisobutylene is greater than 1.2. After the reaction is completed, add an appropriate amount of n-heptane to dissolve the product, remove excess maleic anhydride, and remove n-heptane by vacuum distillation to obtain polyisobutylene succinic anhydride;

[0044] Step 2: Add a certain amount of polyisobutylene succinic anhydride and 3-(3-hydroxypropyl)phenol in proportion to a four-necked flask equipped with a thermometer, a reflux condenser and a stirrer, turn on the stirrer and condense water, use xylene as a water-carrying agent, heat to 160°C under nitrogen replacement protection conditions to react for 4 hours, cool down and wash with NN dimethylformamide, filter, and dry in an oven at 60°C for 12 hours to obtain a reddish-brown viscous solid, which is a polyisobutylene succinic anhydride derivative. When used, a certain amount of dispersant solvent needs to be added to prepare a solution.

[0045] Step 3: Mix the prepared polyisobutylene succinic anhydride derivative with the dispersant solvent and the second surfactant to obtain an asphalt dispersant.

[0046] The preparation method of N-methylmaleimide-styrene copolymer is as follows:

[0047] The obtained product is obtained by suspension polymerization of N-methylmaleimide and styrene at 75-80°C with ethanol as solvent and dimethyl peroxide as initiator. The obtained crude product is washed with propanol, filtered and dried under vacuum conditions at 50°C to obtain a yellow powder, which is N-methylmaleimide-styrene copolymer.

[0048] Example 1

[0049] A paraffin remover and preventer for high-pressure gas wells is composed of the following components in parts by weight: 70 parts of a solvent, 20 parts of an asphalt dispersant, 5 parts of a pour point depressant synergist, 3 parts of a solubilizer and 2 parts of a first surfactant.

[0050] Among them, the solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1500 and light solvent oil 200#, and the mass ratio is 10:40:20:30. The asphalt dispersant is composed of a main agent, a second surfactant and a dispersant solvent, and the mass ratio is 45:3:52. The main agent is a polyisobutylene succinic anhydride derivative, the second surfactant is polyoxyethylene alkylphenol, and the dispersant solvent is NN dimethylformamide. The pour point depressant and enhancer is a mixture of dodecylbenzene sulfonic acid, ethanolamine and isopropanolamine, and the mass ratio is 3:2:1. The solubilizer is sodium dodecylbenzene sulfonate, and the first surfactant is a mixture of propylene glycol fatty acid esters and propylene glycol monolaurate, and the mass ratio is 1:1.

[0051] Example 2

[0052] A paraffin remover and preventer for high-pressure gas wells is composed of the following components in percentage by weight: 70 parts of a solvent, 10 parts of an asphalt dispersant, 15 parts of a pour point depressant, 3 parts of a solubilizer, and 2 parts of a first surfactant.

[0053] Among them, the solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1500 and light solvent oil 200#, and the mass ratio is 15:35:20:30. The asphalt dispersant is composed of a main agent, a second surfactant and a dispersant solvent, and the mass ratio is 45:3:52. The main agent is a polyisobutylene succinic anhydride derivative, the second surfactant is polyoxyethylene octylphenyl ether, and the dispersant solvent is NN dimethylformamide. The pour point depressant and enhancer is a mixture of dodecylbenzene sulfonic acid, ethanolamine and isopropanolamine, and the mass ratio is 3:2:1. The solubilizer is sodium dodecylbenzene sulfonate, and the surfactant is a mixture of propylene glycol fatty acid esters and propylene glycol monolaurate, and the mass ratio is 1:1.

[0054] Example 3

[0055] A paraffin remover and preventer for high-pressure gas wells is composed of the following components in percentage by weight: 65 parts of a solvent, 15 parts of an asphalt dispersant, 10 parts of a pour point depressant, 8 parts of a solubilizer, and 2 parts of a first surfactant.

[0056] Among them, the solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1500 and light solvent oil 90#, and the mass ratio is 10:45:10:35. The asphalt dispersant is composed of a main agent, a second surfactant and a dispersant solvent, and the mass ratio is 40:3:57. The main agent is a polyisobutylene succinic anhydride derivative, the second surfactant is a mixture of polyoxyethylene alkylphenol and polyoxyethylene octylphenyl ether, and the mass ratio is 2:1. The dispersant solvent is NN dimethylformamide. The pour point depressant and enhancer is a mixture of dodecylbenzene sulfonic acid, ethanolamine and isopropanolamine, and the mass ratio is 3:2:1. The solubilizer is sodium dodecylbenzene sulfonate, and the first surfactant is a mixture of propylene glycol fatty acid esters and propylene glycol monolaurate, and the mass ratio is 1:3.

[0057] Example 4

[0058] A paraffin remover and preventer for high-pressure gas wells is composed of the following components in percentage by weight: 65 parts of a solvent, 15 parts of an asphalt dispersant, 10 parts of a pour point depressant, 8 parts of a solubilizer, and 2 parts of a first surfactant.

[0059] Among them, the solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1800, light solvent oil 90#, light solvent oil 120# and light solvent oil 200#, and the mass ratio is 10:40:20:10:10:10. The asphalt dispersant is composed of a main agent, a second surfactant and a dispersant solvent, and the mass ratio is 33:2:65. The main agent is a polyisobutylene succinic anhydride derivative, the second surfactant is a mixture of polyoxyethylene alkylphenol and polyoxyethylene octylphenyl ether, and the mass ratio is 1:1. The dispersant solvent is NN dimethylformamide. The pour point depressant and enhancer is a mixture of dodecylbenzene sulfonic acid, ethanolamine and isopropanolamine, and the mass ratio is 3:2:1. The solubilizer is sodium dodecylbenzene sulfonate, and the first surfactant is a mixture of propylene glycol fatty acid ester and propylene glycol monolaurate in a weight ratio of 1:1.

[0060] Example 5

[0061] A paraffin remover and preventer for high-pressure gas wells is composed of the following components in percentage by weight: 60 parts of a solvent, 20 parts of an asphalt dispersant, 15 parts of a pour point depressant, 2 parts of a solubilizer, and 3 parts of a first surfactant.

[0062] Among them, the solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1800, light solvent oil 90# and light solvent oil 120#, and the mass ratio is 10:35:15:30:10. The asphalt dispersant is composed of a main agent, a second surfactant and a dispersant solvent, and the mass ratio is 30:1:69. The main agent is a polyisobutylene succinic anhydride derivative, the second surfactant is a mixture of polyoxyethylene octylphenyl ether, and the dispersant solvent is NN dimethylformamide. The pour point depressant is a mixture of dodecylbenzene sulfonic acid, ethanolamine and isopropanolamine, and the mass ratio is 3:2:1. The solubilizer is sodium dodecylbenzene sulfonate, and the first surfactant is a mixture of propylene glycol fatty acid esters and propylene glycol monolaurate, and the mass ratio is 2:3.

[0063] Example 6

[0064] The only difference from Example 1 is that the component contents are different:

[0065] A paraffin remover and preventer for high-pressure gas wells is composed of the following components in parts by weight: 80 parts of a solvent, 10 parts of an asphalt dispersant, 5 parts of a pour point depressant synergist, 2 parts of a solubilizer and 2 parts of a first surfactant.

[0066] Example 7

[0067] The only difference from Example 1 is that the component contents are different:

[0068] A paraffin remover and preventer for high-pressure gas wells is composed of the following components in parts by weight: 60 parts of a solvent, 20 parts of an asphalt dispersant, 7 parts of a pour point depressant synergist, 8 parts of a solubilizer and 5 parts of a first surfactant.

[0069] Example 8

[0070] The only difference from Example 1 is that the component contents are different:

[0071] A paraffin remover and preventer for high-pressure gas wells is composed of the following components in parts by weight: 60 parts of a solvent, 12 parts of an asphalt dispersant, 15 parts of a pour point depressant synergist, 8 parts of a solubilizer and 5 parts of a first surfactant.

[0072] Example 9

[0073] The only difference from Example 1 is that the contents of the components in the solvent are different:

[0074] The solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1500 and light solvent oil 200#, and the mass ratio thereof is 20:30:10:40.

[0075] Example 10

[0076] The only difference from Example 1 is that the contents of the components in the solvent are different:

[0077] The solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1500 and light solvent oil 200#, and the mass ratio thereof is 10:30:10:50.

[0078] Embodiment 11

[0079] The only difference from Example 1 is that the contents of the components in the solvent are different:

[0080] The solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1500 and light solvent oil 200#, and the mass ratio thereof is 10:50:20:20.

[0081] Example 12

[0082] The only difference from Example 1 is that the contents of the components in the solvent are different:

[0083] The solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1500 and light solvent oil 200#, and the mass ratio thereof is 10:30:10:50.

[0084] Embodiment 13

[0085] The only difference from Example 1 is that the contents of the components in the solvent are different:

[0086] The solvent is composed of N-methylmaleimide-styrene copolymer, xylene, heavy aromatic solvent oil S1500 and light solvent oil 200#, and the mass ratio thereof is 5:30:20:55.

[0087] Embodiment 14

[0088] The only difference from Example 4 is that the first surfactant is only propylene glycol monolaurate.

[0089] Embodiment 15

[0090] The only difference from Example 4 is that only ethanolamine is used as the pour point depressant synergist.

[0091] According to the SY / T 6300 "Technical Conditions for Wax Removers and Wax Inhibitors for Oil Production" standard, wax samples taken from the inner wall of a high-pressure gas well in a northwest oil field were prepared into standard wax balls. The dissolution time of 1g wax ball in 15mL wax remover and wax inhibitor was measured at 45°C, and the wax dissolution rate of the wax remover and wax inhibitor was calculated in g / min. The wax crystal modifier type wax remover and wax inhibitor was also tested according to the SY / T 6300 standard. The oil sample used was the undoped produced fluid of the oil field, with a water content of less than 10%. The wax prevention rate was calculated by measuring the difference in the amount of paraffin deposited on the inner wall of the steel cup with / without wax remover and wax inhibitor, and the viscosity reduction rate was calculated by measuring the change in the torque value of the rotor under the conditions of adding / not adding wax remover and wax inhibitor. The test results are shown in Table 1:

[0092] Table 1

[0093]

[0094] It can be seen from the above table that the five kinds of wax removal and prevention agents prepared by the present invention not only have a good wax dissolving effect on the high carbon number wax at the western oil field site, but also have excellent wax prevention and viscosity reduction effects on the crude oil at the site. After adding the wax removal and prevention agents prepared by the present invention, the wax dissolving rate of the wax ball, the wax prevention rate and the viscosity reduction rate of the crude oil are far greater than the requirements of the SY / T 6300 standard (the wax dissolving rate is greater than 0.016 g / min, and the wax prevention rate and the viscosity reduction rate are both ≥30%).

[0095] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A wax removal and prevention agent, characterized in that: The wax remover and preventer comprises, by weight, 60 to 80 parts of a solvent, 10 to 20 parts of an asphalt dispersant, 5 to 15 parts of a pour point depressant, 2 to 8 parts of a solubilizer, and 2 to 5 parts of a first surfactant; wherein the solvent comprises N-methylmaleimide-styrene copolymer, xylene, and a 20°C density greater than 0.979 g / cm 3 Heavy aromatic solvent oil and density at 20℃ is 0.66~0.76g / cm 3 Light solvent oil.

2. The wax removal and prevention agent according to claim 1, characterized in that: The N-methylmaleimide-styrene copolymer is obtained by suspension polymerization of N-methylmaleimide and styrene; preferably, the suspension polymerization is carried out with ethanol as solvent and under the action of a peroxide initiator; more preferably, the suspension polymerization temperature is 75-80°C.

3. The wax removal and prevention agent according to claim 1 or 2, characterized in that: The weight ratio of the N-methylmaleimide-styrene copolymer, the xylene, the heavy aromatic solvent oil and the light solvent oil is (10-20): (30-50): (10～20):(20～50)。 4. The wax removal and prevention agent according to any one of claims 1 to 3, characterized in that: The heavy aromatic solvent oil is selected from heavy aromatic solvent oil S1500# and / or heavy aromatic solvent oil S1800#, and the light solvent oil is selected from one or more of solvent oil 6#, solvent oil 90#, solvent oil 120# and solvent oil 200#; More preferably, the heavy aromatic solvent oil is heavy aromatic solvent oil S1500#, and the light solvent oil is solvent oil 200#; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1500#, and the light solvent oil is solvent oil 90#; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1800#, and the light solvent oil is a mixed solvent of solvent oil 90#, solvent oil 120# and solvent oil 200# in a weight ratio of 1:1:1; or, the heavy aromatic solvent oil is heavy aromatic solvent oil S1800#, and the light solvent oil is a mixed solvent of solvent oil 90# and solvent oil 120# in a weight ratio of 3:1; Preferably, the pour point depressant and enhancer is a mixture of alkylbenzene sulfonic acid and an alcoholamine compound; more preferably, the alkylbenzene sulfonic acid is dodecylbenzene sulfonic acid, and the alcoholamine compound is ethanolamine and / or isopropanolamine; most preferably, the pour point depressant and enhancer is a mixture of dodecylbenzene sulfonic acid, ethanolamine and isopropanolamine in a weight ratio of (2.8-3.2):(1.8-2.2):1; Preferably, the solubilizer is alkylbenzene sulfonate, more preferably sodium dodecylbenzene sulfonate; Preferably, the first surfactant is propylene glycol fatty acid ester and / or propylene glycol monolaurate, more preferably a mixture of propylene glycol fatty acid ester and propylene glycol monolaurate in a weight ratio of (1-2):(1-3).

5. The wax removal and prevention agent according to any one of claims 1 to 3, characterized in that: The asphalt dispersant includes a dispersant main agent, a second surfactant and a dispersant solvent, wherein the dispersant main agent is a polyisobutylene succinic anhydride derivative; preferably, the polyisobutylene succinic anhydride derivative is an esterification reaction product of polyisobutylene succinic anhydride and 3-(3-hydroxypropyl)phenol.

6. The wax removal and prevention agent according to claim 5, characterized in that: The polyisobutylene succinic anhydride derivative is prepared by the following preparation method: Step S1, reacting isobutylene and maleic anhydride crystals at 180±5° C. for 2 to 2.5 hours, then adding excess maleic anhydride to the reaction system, and adjusting the temperature to 230±5° C. to continue reacting for 3.5 to 4.5 hours, so that the degree of substitution of maleic anhydride on polyisobutylene is greater than 1.2, to obtain polyisobutylene succinic anhydride; Step S2, reacting the polyisobutylene succinic anhydride and 3-(3-hydroxypropyl)phenol under the action of a water-carrying agent at a temperature of 160±5° C. for 4 to 5 hours to obtain the polyisobutylene succinic anhydride derivative; Preferably, in step S1, after the excessive addition of maleic anhydride and the continued reaction are completed, the product system is dissolved with n-heptane to remove the unreacted maleic anhydride, and then subjected to reduced pressure distillation to obtain the polyisobutylene succinic anhydride; Preferably, in step S2, after the reaction is completed, the reaction system is cooled, washed, filtered and dried in sequence to obtain the polyisobutylene succinic anhydride derivative.

7. The wax removal and prevention agent according to claim 5, characterized in that: The second surfactant is selected from polyoxyethylene alkylphenol and / or polyoxyethylene octylphenyl ether, and the dispersant solvent is selected from NN dimethylformamide; Preferably, the weight content of the second surfactant in the asphalt dispersant is 1-3%, and the weight content of the dispersant solvent in the asphalt dispersant is 50-70%.

8. A method for preparing the wax removal and prevention agent according to any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: mixing and dispersing a solvent, an asphalt dispersant, a pour point depressant, a solubilizer and a first surfactant according to a ratio to obtain the wax removal and prevention agent; wherein the solvent comprises N-methylmaleimide-styrene copolymer, xylene, and a 20°C density greater than 0.979 g / cm 3 Heavy aromatic solvent oil and density at 20℃ is 0.66~0.76g / cm 3 Light solvent oil.

9. The method for preparing the wax removing and preventing agent according to claim 8, characterized in that: The preparation method comprises the following steps: The xylene, the heavy aromatic solvent oil and the light solvent oil are mixed and stirred; Under stirring, sequentially adding the N-methylmaleimide-styrene copolymer, the first surfactant, the solubilizer and the pour point depressant synergist to the system; Under stirring, further adding the asphalt dispersant to the system to obtain the wax removal and prevention agent; Preferably, before adding the asphalt dispersant, the dispersant main agent, the second surfactant and the dispersant solvent are mixed in advance to prepare the asphalt dispersant.

10. Use of the paraffin removal and prevention agent according to any one of claims 1 to 7 as a paraffin removal and prevention agent for high-pressure gas well casing.

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