Styrene-short-chain olefin-long-chain olefin-N-alkyl maleimide copolymer, and preparation method and application thereof

Abstract

The invention discloses a styrene-short-chain olefin-long-chain olefin-N-alkyl maleimide copolymer as well as a preparation method and application thereof, and belongs to the field of oilfield exploitation. The invention relates to a preparation method of a styrene-short-chain olefin-long-chain olefin-N-alkyl maleimide copolymer. The preparation method comprises the following steps: (1) preparing a styrene-short-chain olefin-long-chain olefin-maleic anhydride quadripolymer; and (2) carrying out a reaction on primary amine and an anhydride structural unit in the styrene-short-chain olefin-long-chain olefin-maleic anhydride quadripolymer, so as to obtain the styrene-short-chain olefin-long-chain olefin-N-alkyl maleimide copolymer. The technical problems of high raw material cost, narrow working temperature range and poor paraffin removal and inhibition performance of the paraffin removal and inhibition agent in the prior art are solved.

Description

Technical Field

[0001] The invention belongs to the field of oilfield exploitation, in particular to a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, a preparation method and application thereof. Background Art

[0002] During the recovery of natural gas and crude oil, wax deposition is a common problem. Wax deposition may occur in reservoirs, wellbores and surface pipelines, among which wax deposition in surface pipelines is more obvious and has the most significant impact. The currently used wax removal and prevention processes include well repair operations, solvent 1 cleaning (light hydrocarbons, hot oil, heating, etc.), and preventive measures (continuous injection of wax removal and prevention agents, such as liquids and particles, which can slowly release chemicals in reservoir fluids). The hot washing distance is short and the thermal efficiency is low; the types of wax removal and prevention agents are single, with poor permeability and insignificant wax removal and prevention effects; whether there is wax deposition in the cracks of dense and low permeability reservoirs is unknown, and there are no preventive measures. Wax deposition in the cracks will lead to a decrease in production, slow or difficult wellbore cleaning, and the expected maximum recovery rate cannot be achieved; the specific location of the solid wax preventer in the horizontal wellbore is unclear, and the wax deposition problem is still not effectively solved. Natural gas wax inhibitors are currently mainly restricted by foreign products, with high prices and supply that cannot be effectively guaranteed.

[0003] Using chemical agents to remove and prevent wax from oil and gas wells and pipelines is a wax removal and prevention technology that is currently widely used in oil fields. This is because when using chemical agents for wax removal and prevention, the agents are usually added from the annular space or ground pipeline, so it does not affect the normal production of oil and gas wells and pipeline transportation, etc., and has a good wax removal and prevention effect.

[0004] Commonly used chemical wax inhibitors are divided into polycyclic aromatic hydrocarbons, surfactant wax inhibitors, and polymer wax inhibitors. Surfactant wax inhibitors are also called wax crystal dispersants. The surfactants used for wax inhibition can be oil-soluble or water-soluble, and the working principles of the two are different. Many literatures and monographs believe that water-soluble surfactants prevent wax deposition by adsorbing on the wax surface, turning the non-polar wax surface into a polar surface; oil-soluble surfactants prevent the further growth of wax crystals by adsorbing on the wax crystal surface, turning the non-polar wax crystal surface into a polar wax crystal surface. Polymer wax inhibitors are also called wax crystal modifiers. These wax inhibitors are oil-soluble comb polymers with side chains of a certain length in the molecules. They have structures and polar groups similar to paraffin molecules in the main chain or side chain of the molecules. At lower temperatures, the paraffin-like structures in their molecules form eutectics with paraffin molecules. Because there are also polar groups in their molecules, the formed crystal nuclei are distorted and deformed, inhibiting the further growth of wax crystals. Summary of the invention

[0005] The purpose of the present invention is to overcome the disadvantages of the prior art and provide a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, a preparation method and application thereof.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A method for preparing a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer comprises the following steps:

[0008] (1) preparing a styrene-short chain olefin-long chain olefin-maleic anhydride tetrapolymer;

[0009] (2) reacting the anhydride structural unit in the styrene-short chain olefin-long chain olefin-maleic anhydride tetrapolymer with a primary amine to obtain a styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer.

[0010] Furthermore, the operation of step (1) is:

[0011] Add styrene, short-chain olefin, long-chain olefin and maleic anhydride to solvent 1, stir at 70-90° C. to form a uniform mixture, then add an initiator, raise the temperature to 110-135° C. and react for 2-4 hours to obtain a styrene-short-chain olefin-long-chain olefin-maleic anhydride tetrapolymer.

[0012] Furthermore, the carbon chain length of the short-chain olefin is between C6 and C12; and / or

[0013] The carbon chain length of the long-chain olefin is between C18 and C30; and / or

[0014] The molar ratio of styrene, short-chain olefin, long-chain olefin and maleic anhydride is (0.5-0.8):(0.5-0.8):(0.5-0.8):(1.0-1.6); and / or

[0015] The solvent 1 is one or more of toluene, xylene, trimethylbenzene, solvent oil, heavy naphtha and kerosene; and / or

[0016] The initiator is one or more of azobisisobutyl cyanide, dibenzoyl peroxide and tert-butyl perbenzoate; and / or

[0017] The added amount of the initiator is 0.01% to 0.05% of the total mass of styrene, short-chain olefin, long-chain olefin and maleic anhydride.

[0018] Furthermore, the short-chain olefins and the long-chain olefins are both α-olefins.

[0019] Furthermore, the specific operation of step (2) is:

[0020] A primary amine is added to the styrene-short chain olefin-long chain olefin-maleic anhydride tetrapolymer, and then the reaction is continued at 110-135° C. for 6-24 hours to obtain a styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer.

[0021] Furthermore, the carbon chain length of the primary amine is C12 to C24.

[0022] Furthermore, the water generated during the reaction is removed through an oil-water separator in the reflux process.

[0023] A styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is prepared according to the above preparation method.

[0024] The styrene-short-chain olefin-long-chain olefin-N-alkyl maleimide copolymer of the present invention is used as a wax inhibitor in natural gas wax inhibition.

[0025] Further: the styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is directly used as a wax inhibitor, and the wax inhibitor is added to a natural gas transmission pipeline, a crude oil transmission pipeline and / or an oil and gas processing device; or

[0026] The styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is mixed with solvent 2 in a mass ratio of (1-3):(1-10) and used as a wax inhibitor. The wax inhibitor is added to a natural gas transmission pipeline, a crude oil transmission pipeline and / or an oil and gas processing device.

[0027] Further, the solvent 2 is one or more of toluene, xylene, trimethylbenzene, solvent oil, naphtha, kerosene, C9 aromatics, mixed aromatics, diesel and gasoline; or / and

[0028] The amount of the wax inhibitor added is 500 to 3000 ppm.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] The present invention discloses a polystyrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer obtained by copolymerization and side group modification. The polystyrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is a comb-like structure and has a long-chain alkyl structure and polar groups similar to the structure of paraffin wax. It can form a cocrystal with paraffin wax, inhibit or weaken the crystallization and precipitation of paraffin wax, dissolve the crystallized paraffin wax, and achieve a good wax removal and prevention effect. The wax removal and prevention agent has a low freezing point and can be applied to severe cold and low temperature conditions. The present invention solves the technical problems of high raw material cost, narrow working temperature range and poor wax removal and prevention performance of wax removal and prevention agents in the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0033] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those described herein. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0034] See also Figure 1 , Figure 1 The flowchart of the present invention is a method for preparing a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, comprising the following steps:

[0035] (1) preparing a styrene-short chain olefin-long chain olefin-maleic anhydride tetrapolymer;

[0036] (2) reacting the primary amine with the anhydride structural unit in the styrene-short chain olefin-long chain olefin-maleic anhydride tetrapolymer to obtain a styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer. Specific examples are described below.

[0037] Example 1

[0038] This embodiment provides a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, and the styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is obtained by the following steps:

[0039] First, 0.5 mol of styrene, 0.5 mol of hexene, 0.5 mol of octadecene and 1 mol of maleic anhydride were weighed into a three-necked flask, and then toluene was added and stirred at 80°C for 30 min to mix them evenly, 0.01 mol of azobisisobutyl cyanide was added, and then the temperature was raised to 125°C to react for 3 h, and finally 1 mol of octadecylamine was added to continue the reaction for 5 h to obtain a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer.

[0040] Example 2

[0041] This embodiment provides a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, and the styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is obtained by the following steps:

[0042] First, 0.6 mol of styrene, 0.5 mol of hexene, 0.4 mol of octadecene and 1.2 mol of maleic anhydride were weighed into a three-necked flask, and then xylene was added and stirred at 85°C for 30 min to mix them evenly, 0.01 mol of dibenzoyl peroxide was added, and then the temperature was raised to 130°C to react for 3 h, and finally 1 mol of octadecylamine was added to continue the reaction for 10 h to obtain a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer.

[0043] Example 3

[0044] This embodiment provides a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, and the styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is obtained by the following steps:

[0045] First, weigh 0.5 mol of styrene, 0.5 mol of hexene, 0.5 mol of octadecene and 1.2 mol of maleic anhydride into a three-necked flask, then add trimethylbenzene, stir at 80°C for 30 min to mix evenly, add 0.01 mol of tert-butyl perbenzoate, then heat to 135°C to react for 2 h, finally add 1 mol of octadecylamine and continue the reaction for 10 h to obtain styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer.

[0046] Example 4

[0047] This embodiment provides a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, and the styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is obtained by the following steps:

[0048] First, 0.5 mol of styrene, 0.5 mol of hexene, 0.5 mol of octadecene and 1.0 mol of maleic anhydride were weighed into a three-necked flask, and then kerosene was added and stirred at 80°C for 30 min to mix them evenly, 0.01 mol of tert-butyl perbenzoate and dibenzoyl peroxide were added, and then the temperature was raised to 135°C for reaction for 2 h, and finally 1 mol of octadecylamine was added and the reaction was continued for 18 h to obtain a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer.

[0049] Example 5

[0050] The styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer prepared in Examples 1-4 was used to characterize the anti-wax performance of the styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer in crude oil.

[0051] The evaluation of wax inhibitors is carried out in accordance with the standard SYT6300-2009 "Technical conditions for oil production cleaners and wax inhibitors". The test results are shown in Table 1.

[0052] Table 1 Wax prevention performance of the products of Examples 1-4 in crude oil

[0053]

[0054] It can be seen from Table 1 that the paraffin inhibitor of the present invention can effectively inhibit the crystallization of paraffin on the tube wall, and can also adhere to the surface of paraffin to inhibit crystallization, and inhibit the aggregation and growth of paraffin crystals.

[0055] Example 6

[0056] The styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer prepared in Examples 1-4 was used to characterize the anti-wax performance of the styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer in natural gas condensate. A mixture of the styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer and solvent 2 was added to the natural gas condensate, cooled to -15°C, maintained for 2 hours, and the flow state of the condensate was observed.

[0057] Table 2 Flow state of the condensate oil prepared by the products of Examples 1-4 kept at -15°C for 2 hours

[0058]

[0059] As can be seen from Table 2, the present invention can effectively inhibit the precipitation of paraffin in natural gas condensate and prevent the growth of wax crystals, thereby ensuring that the condensate will not solidify under low temperature conditions and maintain good fluidity.

[0060] Example 7

[0061] The styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer prepared in Examples 1-4 was used to characterize the anti-wax performance of the styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer in natural gas condensate. A mixture of styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer and solvent 2 was added to natural gas condensate, cooled to -18°C, maintained for 2 hours, and the flow state of the condensate was observed.

[0062] Table 3 Flow state of the condensate oil prepared by the products of Examples 1-4 kept at -18°C for 2 hours

[0063]

[0064] As shown in Table 3, the present invention can effectively inhibit the precipitation of paraffin in natural gas condensate and prevent the growth of wax crystals, thereby ensuring that the condensate will not solidify under low temperature conditions and maintain good fluidity. The heavy wax components in the natural gas will first form a liquid state, and will not further precipitate due to the effect of the wax inhibitor, so they will not aggregate into the transportation pipeline. Since the wax inhibitor is added to the natural gas in the form of a spray, even if fine wax crystals are precipitated from the natural gas, they will first adhere to the wax inhibitor droplets. On the one hand, they will not continue to aggregate and grow. On the other hand, since the wax inhibitor has a good wax dissolving ability, the solid wax crystals will be transformed into a liquid phase, and finally enter the condensate and be discharged with the condensate.

[0065] The invention has the characteristics of easy-to-obtain raw materials, simple preparation process, wide application range and remarkable anti-wax effect.

[0066] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, characterized in that: The following steps are involved: (1) preparing a styrene-short chain olefin-long chain olefin-maleic anhydride tetrapolymer; (2) reacting the anhydride structural unit in the styrene-short chain olefin-long chain olefin-maleic anhydride tetrapolymer with a primary amine to obtain a styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer.

2. The method for preparing the styrene-short-chain olefin-long-chain olefin-maleic anhydride tetrapolymer according to claim 1, characterized in that: The operation of step (1) is: Add styrene, short-chain olefin, long-chain olefin and maleic anhydride to solvent 1, stir at 70-90° C. to form a uniform mixture, then add an initiator, raise the temperature to 110-135° C. and react for 2-4 hours to obtain a styrene-short-chain olefin-long-chain olefin-maleic anhydride tetrapolymer.

3. The method for preparing the styrene-short-chain olefin-long-chain olefin-maleic anhydride tetrapolymer according to claim 2, characterized in that: The carbon chain length of the short-chain olefin is between C6 and C12; and / or The carbon chain length of the long-chain olefin is between C18 and C30; and / or The molar ratio of styrene, short-chain olefin, long-chain olefin and maleic anhydride is (0.5-0.8):(0.5-0.8):(0.5-0.8):(1.0-1.6); and / or The solvent 1 is one or more of toluene, xylene, trimethylbenzene, solvent oil, heavy naphtha and kerosene; and / or The initiator is one or more of azobisisobutyl cyanide, dibenzoyl peroxide and tert-butyl perbenzoate; and / or The added amount of the initiator is 0.01% to 0.05% of the total mass of styrene, short-chain olefin, long-chain olefin and maleic anhydride.

4. The method for preparing the styrene-short-chain olefin-long-chain olefin-maleic anhydride tetrapolymer according to claim 2, characterized in that: The short-chain olefins and the long-chain olefins are both α-olefins.

5. The method for preparing the styrene-short-chain olefin-long-chain olefin-maleic anhydride tetrapolymer according to claim 1, characterized in that: The specific operation of step (2) is: A primary amine is added to the styrene-short chain olefin-long chain olefin-maleic anhydride tetrapolymer, and then the reaction is continued at 110-135° C. for 6-24 hours to obtain a styrene-short chain olefin-long chain olefin-N-alkylmaleimide copolymer.

6. The method for preparing the styrene-short-chain olefin-long-chain olefin-maleic anhydride tetrapolymer according to claim 5, characterized in that: The carbon chain length of the primary amine is C12 to C24.

7. The method for preparing the styrene-short-chain olefin-long-chain olefin-maleic anhydride tetrapolymer according to claim 5, characterized in that: The water generated during the reaction is removed through the oil-water separator in the reflux process.

8. A styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer, characterized in that: Prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of the styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer according to claim 8 as a paraffin inhibitor in natural gas paraffin prevention.

10. The use according to claim 9, characterized in that: The styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is directly used as a wax inhibitor, and the wax inhibitor is added to a natural gas transmission pipeline, a crude oil transmission pipeline and / or an oil and gas processing device; or The styrene-short-chain olefin-long-chain olefin-N-alkylmaleimide copolymer is mixed with solvent 2 in a mass ratio of (1-3):(1-10) and used as a wax inhibitor. The wax inhibitor is added to a natural gas transmission pipeline, a crude oil transmission pipeline and / or an oil and gas processing device.

11. The use according to claim 10, characterized in that: The solvent 2 is one or more of toluene, xylene, trimethylbenzene, solvent oil, naphtha, kerosene, C9 aromatics, mixed aromatics, diesel and gasoline; or / and The amount of the wax inhibitor added is 500 to 3000 ppm.

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