阅读说明：本技术 一种碳酸钙阻垢剂及其制备方法 (Calcium carbonate scale inhibitor and preparation method thereof ) 是由 扈俊颖 王恒 钟显康 张智 侯铎 曾德智 施太和 于 2019-11-26 设计创作，主要内容包括：本发明公开了一种碳酸钙阻垢剂及其制备方法,属于阻垢剂技术领域。本发明的碳酸钙阻垢剂,其原料包括：马来酸酐、乙酸乙烯酯、乙烯基磺酸钠、L-谷氨酸和引发剂,本发明的阻垢剂具有优异的阻垢性能,在低剂量下能够很好的抑制碳酸钙的生成,而且此聚合物具有很强的分散性能,在生成垢的同时使其疏松多孔,不易沉积在管道表面。本发明的碳酸钙阻垢剂可在低剂量下具有很好的阻垢效果,该阻垢剂在静态阻垢法测定中阻垢率可以达到90％以上,对于碳酸钙垢同时也具有很好的分散效果,使形成的碳酸钙垢不在管道中沉积,从而不易将管道和阀门堵塞,同时也是一种环境友好型阻垢剂。(The invention discloses a calcium carbonate scale inhibitor and a preparation method thereof, belonging to the technical field of scale inhibitors. The calcium carbonate scale inhibitor comprises the following raw materials: the scale inhibitor disclosed by the invention has excellent scale inhibition performance, can well inhibit the generation of calcium carbonate under low dosage, has strong dispersion performance, and is loose and porous while generating scale and not easy to deposit on the surface of a pipeline. The calcium carbonate scale inhibitor has a good scale inhibition effect under a low dosage, has a scale inhibition rate of over 90 percent in a static scale inhibition method, has a good dispersion effect on calcium carbonate scale, prevents the formed calcium carbonate scale from depositing in a pipeline, is not easy to block the pipeline and a valve, and is an environment-friendly scale inhibitor.)

1. The calcium carbonate scale inhibitor is characterized by comprising the following raw materials: maleic anhydride, vinyl acetate, sodium vinyl sulfonate, L-glutamic acid and an initiator, wherein the molar ratio of the maleic anhydride to the vinyl acetate to the sodium vinyl sulfonate to the L-glutamic acid is (2-5): (1-5): (0.1-1): 1, the addition amount of the initiator is 4-14% of the total mass of the maleic anhydride, the vinyl acetate, the sodium vinylsulfonate and the L-glutamic acid.

2. The calcium carbonate scale inhibitor according to claim 1, wherein the molar ratio of maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid is (3-5): (2-4): (0.3-0.5): 1.

3. the calcium carbonate scale inhibitor according to claim 2, wherein the molar ratio of maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid is 5:3:0.5: 1.

4. The calcium carbonate scale inhibitor according to any one of claims 1 to 3, wherein the initiator is (NH)₄)₂S₂O₄。

5. The calcium carbonate scale inhibitor of claim 4Characterized in that (NH) is₄)₂S₂O₄The addition amount of the sodium-vinyl acetate copolymer is 6-12% of the total mass of the maleic anhydride, the vinyl acetate, the sodium vinylsulfonate and the L-glutamic acid.

6. The calcium carbonate scale inhibitor according to claim 5, wherein the (NH) is₄)₂S₂O₄The addition amount of (A) is 8% of the total mass of maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid.

7. The method for preparing a calcium carbonate scale inhibitor according to any one of claims 1 to 6, which comprises: (1) mixing maleic anhydride and L-glutamic acid, adding water to dissolve the maleic anhydride and the L-glutamic acid, and then respectively adding vinyl acetate and sodium vinyl sulfonate to obtain a monomer mixture;

(2) heating the monomer mixture to 50-60 ℃, and then dropwise adding an initiator solution prepared from an initiator and water into the monomer mixture;

(3) after the dropwise addition, the temperature is raised to 60-90 ℃, and the reaction is carried out for 2-5h at constant temperature, thus obtaining the calcium carbonate scale inhibitor.

8. The method for preparing calcium carbonate scale inhibitor according to claim 7, wherein in the step (2), the initiator solution is added dropwise within 15-25 min.

Technical Field

The invention relates to the technical field of scale inhibitors, and particularly relates to a calcium carbonate scale inhibitor and a preparation method thereof.

Background

With the continuous development of oil and gas fields, the original formation energy is gradually depleted, so the formation energy is supplemented by adopting a method of manually injecting liquid or gas into the formation, and the yield of crude oil is ensured. Many oil fields currently employ methods of reinjection of treated produced water as injection water into the formation to supplement formation energy. However, there are many problems to be solved in oilfield waterflooding development, of which calcium carbonate scaling is one of the most common. Calcium carbonate is often generated in a shaft of an oil production well, a ground gathering and transportation system, underground equipment, a water injection stratum and an underground reservoir, so that the problems of blockage of a water injection well and an oil layer, blockage of a shaft of the oil well and a ground oil and gas gathering and transportation equipment pipeline, even damage of the equipment and the like can be caused, the yield of the oil well is low, even the oil well is scrapped and the production is stopped, the yield of the whole oil field is influenced, and the economic loss of the oil field is brought. The main method for solving the problem at present is to add the scale inhibitor, and the method has the advantages of simple equipment, convenient operation, low investment cost and good scale inhibition effect, and can effectively solve the problem caused by scale formation. The existing scale inhibitor mainly comprises phosphorus-containing scale inhibitor, and the use of the scale inhibitor can cause water eutrophication, generate red tide and other phenomena, and seriously pollute water quality.

Disclosure of Invention

The invention provides a calcium carbonate scale inhibitor and a preparation method thereof, aiming at solving the problem of water eutrophication caused by the existing calcium carbonate scale inhibitor. The technical scheme for solving the technical problems is as follows:

a calcium carbonate scale inhibitor comprises the following raw materials: maleic anhydride, vinyl acetate, sodium vinylsulfonate, L-glutamic acid and an initiator, wherein the molar ratio of the maleic anhydride to the vinyl acetate to the sodium vinylsulfonate to the L-glutamic acid is (2-5): (1-5): (0.1-1): 1, the addition amount of the initiator is 4-14% of the total mass of the maleic anhydride, the vinyl acetate, the sodium vinylsulfonate and the L-glutamic acid.

The invention takes four monomers of maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid as raw materials, and the quadripolymer scale inhibitor is obtained by polymerization under the action of an initiator, thereby solving the pollution problem of the phosphorus-containing scale inhibitor, having excellent effect on preventing the generation of calcium carbonate, and being a biodegradable environment-friendly scale inhibitor.

The scale inhibition principle of the scale inhibitor of the present invention is explained below.

According to the invention, maleic anhydride is selected as one of monomers, and the unsaturated bond and two carboxylic acid groups contained in the maleic anhydride have good chelating capacity with calcium ions, so that the carboxylic acid and the calcium ions form a chelate, the solubility of the calcium ions in a solution is increased, the solution is not easy to generate precipitation due to supersaturation, and the formation of calcium carbonate is prevented; vinyl acetate is selected as one of the monomers, contains unsaturated double bonds and ester groups, can play a role in promoting scale inhibition when polymerized with carboxylic acid monomers, enhances the solubility of the scale inhibitor, and makes up the defect that the polycarboxylic acid scale inhibitor is easy to form gel; the sodium vinylsulfonate is selected as one of the monomers, contains unsaturated double bonds and sulfonic acid groups, can have good dispersion effect on inorganic scale, and can also enhance the salt resistance and temperature resistance of the scale inhibitor; the L-glutamic acid is selected as one of the monomers, contains two carboxyl groups and amino groups, has certain chelating capacity and can also increase the solubility in water.

The invention selects four monomers of maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid to combine, and utilizes carboxyl functional groups of the maleic anhydride to form chelate with calcium ions, thereby increasing the solubility of the calcium ions in the solution and ensuring that the solution is not easy to generate precipitation due to supersaturation. However, polymerization using only carboxyl groups is likely to form a gel, and is not easily degraded, which is harmful to the environment. Therefore, the invention adds vinyl acetate on the basis of maleic anhydride, introduces ester group, and can improve the solubility of the maleic anhydride in the aqueous solution; and simultaneously, the sodium vinylsulfonate is added, and the sulfonic group is introduced, so that the high temperature resistance and salt resistance of the scale inhibitor are improved, the service performance of the scale inhibitor is greatly improved, the scale inhibitor has the scale inhibition effect, the high temperature resistance and salt resistance of the scale inhibitor are also greatly improved, and the comprehensive performance of the scale inhibitor is better. The invention also adds L-glutamic acid which contains carboxyl and acylamino, can enhance the binding capacity of the scale inhibitor and calcium ions and the solubility of the scale inhibitor, and further improves the scale inhibition performance of scale inhibition.

Further, in a preferred embodiment of the present invention, the molar ratio of the above maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid is (3-5): (2-4): (0.3-0.5): 1.

the scale inhibitor prepared according to the proportion relation has the scale inhibition efficiency of 80-99%.

Further, in a preferred embodiment of the present invention, the above maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid are present in a molar ratio of 5:3:0.5: 1.

The scale inhibitor prepared according to the proportion relation has the scale inhibition efficiency of 99 percent.

Preferably, the molar ratio of maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid can also be 5:3:0.1: 1.

Further, in a preferred embodiment of the present invention, the initiator is (NH)₄)₂S₂O₄。

Selection of (NH) in accordance with the invention₄)₂S₂O₄As an initiator, the compound can be homolytic and decomposed into primary free radicals at a certain temperature to initiate free radical polymerization, has moderate decomposition temperature and high activity, and can be used independently. (NH) in contrast to the other initiators₄)₂S₂O₄The combination with the polymerized monomer in the invention has more outstanding effect.

Further, in a preferred embodiment of the present invention, the (NH) is₄)₂S₂O₄The addition amount of the sodium-vinyl acetate copolymer is 6-12% of the total mass of the maleic anhydride, the vinyl acetate, the sodium vinylsulfonate and the L-glutamic acid.

Further, in a preferred embodiment of the present invention, the (NH) is₄)₂S₂O₄The addition amount of (A) is 8% of the total mass of maleic anhydride, vinyl acetate, sodium vinylsulfonate and L-glutamic acid.

A preparation method of a calcium carbonate scale inhibitor comprises the following steps:

(1) mixing maleic anhydride and L-glutamic acid, adding water to dissolve the maleic anhydride and the L-glutamic acid, and then respectively adding vinyl acetate and sodium vinyl sulfonate to obtain a monomer mixture;

(2) heating the monomer mixture to 50-60 ℃, and then dropwise adding an initiator solution prepared from an initiator and water into the monomer mixture;

(3) after the dropwise addition, the temperature is raised to 60-90 ℃, and the reaction is carried out for 2-5h at constant temperature, thus obtaining the calcium carbonate scale inhibitor.

Preferably, in the step (2), the heating temperature is 50 ℃, 55 ℃ or 60 ℃; in the step (3), the reaction temperature is 60 ℃, 70 ℃, 80 ℃ or 90 ℃, and the corresponding reaction time is 5h, 4h, 3h or 2 h.

Further, in the preferred embodiment of the present invention, in the step (2), the initiator solution is added dropwise within 15 to 25 min.

The dropping time of the initiator solution is limited to 15-25min, so that the molecular weight formed by polymerization is moderate; the method can avoid the problems that the reaction generates implosion phenomenon due to the excessively high dropping speed of the initiator, the total amount of formed scale inhibitors is too small, and the scale inhibition effect is poor, and the problems that the scale inhibition effect is poor due to the unfavorable chelation effect with calcium ions due to the excessively high dropping speed, the excessively large molecular weight of the polymer generated by the reaction and the excessively small distance between molecular groups.

The invention has the following beneficial effects:

the novel tetrapolymer is synthesized by using maleic anhydride, sodium vinylsulfonate, vinyl acetate and L-glutamic acid, the polymer scale inhibitor has excellent scale inhibition performance, can well inhibit the generation of calcium carbonate under low dosage, has strong dispersion performance, is loose and porous while generating scale, and is not easy to deposit on the surface of a pipeline.

The calcium carbonate scale inhibitor has a good scale inhibition effect under a low dosage, has a scale inhibition rate of over 90 percent in a static scale inhibition method, has a good dispersion effect on calcium carbonate scale, prevents the formed calcium carbonate scale from depositing in a pipeline, is not easy to block the pipeline and a valve, and is an environment-friendly scale inhibitor.

Detailed Description

The principles and features of this invention are described below in conjunction with embodiments, which are included to explain the invention and not to limit the scope of the invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

The raw materials used in the present invention are described below.

(1) Maleic anhydride

The maleic anhydride is a flaky crystal, the boiling point of the maleic anhydride is 202 ℃, the maleic anhydride is easily dissolved in most organic solvents such as water, acetone, benzene, chloroform and the like, and the molecular structure of the maleic anhydride is as follows:

(2) vinyl acetate (VAA)

The vinyl acetate is colorless liquid, has a boiling point of 71 ℃, has sweet ether taste, is slightly soluble in water, is soluble in alcohol, acetone, benzene and chloroform, and has a molecular structure as follows:

(3) sodium vinyl sulfonate

The sodium vinylsulfonate is light yellow transparent liquid, is easy to dissolve in water, and has the following molecular structure:

(4) l-glutamic acid

L-glutamic acid is white crystalline powder, is slightly soluble in cold water, is easily soluble in hot water, is almost odorless, has special sour taste, and has the following molecular structure:

the present invention will be further described with reference to the following examples.