Anti-carbon dioxide corrosion inhibitor and preparation method and application thereof

Abstract

The present application relates to oil field chemical additive preparation technical field, it is a kind of carbon dioxide-resistant corrosion inhibitor and its preparation method and application, after the required amount first polymer, second polymer and modified imidazoline are mixed, carbon dioxide-resistant corrosion inhibitor is obtained, wherein, first polymer is comb structure imidazoline, second polymer is linear structure imidazoline.The n imidazolin ring in the first polymer molecule is adsorbed on stainless steel pipe, the adsorption capacity and the scouring performance of corrosion inhibitor are improved, the adsorption of second polymer increases imidazoline, modified imidazoline is introduced by primary amine hydrophobic group, the hydrophobic capacity of monocyclic imidazoline is improved, water phase contact metal surface is further inhibited, and guanidine structure is introduced in imidazolin structure, so that product has strong bactericidal efficacy, polymer chain structure contains carboxylic acid structure, so it has strong complexing calcium, magnesium and other cation ability, can effectively inhibit the problem of carbon dioxide caused by fouling.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil field chemical additives, and is an anti-carbon dioxide corrosion inhibitor as well as a preparation method and application thereof. BACKGROUND

[0002] Corrosive gases such as dissolved oxygen, hydrogen sulfide and carbon dioxide are contained in oil field sewage, which have serious corrosiveness to metal pipelines and equipment in the sewage treatment and reinjection system. Corrosion inhibitors are mainly used to prevent the corrosion and oxidation of metal surfaces. They can inhibit or slow down the metal corrosion process by forming a protective film or other chemical action mechanisms, reducing the contact between the metal surface and the oxygen, moisture and other substances in the environment, thereby preventing the corrosion and oxidation of the metal surface. In oil field development, corrosion inhibitors can be adsorbed on the metal surface to form a protective film, thereby inhibiting and alleviating the corrosion of the metal surface.

[0003] Scaling is one of the most serious problems encountered in the control of oil field water quality. Scaling can occur at various parts of the formation, wellbore or surface, and some wells and oil layers are abandoned prematurely due to scaling deposition in the production layer of the wellbore perforation; scaling can also occur in gravel pack layers, downhole pumps, tubing strings, oil nozzles and oil storage equipment, gathering pipelines, crude oil processing equipment, cooling towers, boilers and water injection and sewage pipelines and any part of the water treatment system. Scaling can cause serious harm to oil field production: scale is a poor conductor of heat, and the formation of scale greatly reduces the heat transfer effect; the deposition of scale can cause local corrosion of equipment and pipelines and damage them; scale can also reduce the cross-sectional area of the water flow, increase the water flow resistance and increase the cleaning cost. Scale inhibitors mainly disperse insoluble inorganic salts in water, prevent or interfere with the deposition and scaling of insoluble inorganic salts on the surface of metals. They can control the formation of scale by dispersion, chelation and other methods, and maintain good heat transfer effect of metal equipment. In oil field development, scale inhibitors can effectively prevent pipe blockage and scaling in water treatment equipment.

[0004] In the oil field water system, mainly the water injection system of reinjected sewage, due to the presence of microorganisms, it has brought great harm to oil field production. The most serious harm is the sulfate-reducing bacteria, whose product hydrogen sulfide has a particularly serious corrosive effect on metals, and the product ferrous sulfide is a substance that causes pipe blockage. The second is saprophytic bacteria and iron bacteria that can produce slime, and when the number of these bacteria exceeds a certain value, they can form an oxygen concentration cell, causing the injection well to be blocked, the injection volume to be reduced, etc. Other organisms such as algae, sulfur bacteria, yeast and mold can also cause blockage and oxygen concentration cells, but the problems caused by them are not as serious as the above-mentioned bacteria. Bactericides can prevent and control plant diseases caused by various pathogenic microorganisms. In oil field development, bactericides are mainly used to inhibit or eliminate microorganisms in water, to avoid damage to equipment caused by bacteria, algae, fungi, etc.

[0005] Therefore, at present, in the oilfield development process and the pipe network gathering and transportation process, corrosion, scaling and bacteria breeding are common problems, which will seriously affect the oilfield production if not effectively controlled. Currently, the corrosion inhibitor, scale inhibitor and bactericide are simply compounded and then added. However, this not only leads to high cost of the medicament, but also poor compatibility between various medicaments, so that the use effect is poor after compounding.

[0006] Therefore, it is necessary to develop a chemical additive with excellent corrosion inhibition effect, bactericidal efficacy and strong complexing ability of calcium, magnesium and other cations for application in oilfield development. SUMMARY

[0007] The present application provides an anti-carbon dioxide corrosion inhibitor and its preparation method and application, which overcomes the shortcomings of the prior art. The anti-carbon dioxide corrosion inhibitor can effectively solve the problems of high cost of medicaments, poor compatibility of various medicaments, easy corrosion, scaling and bacteria breeding when the corrosion inhibitor, scale inhibitor and bactericide are simply compounded and then added in the existing oilfield development.

[0008] One of the technical solutions of the present application is realized by the following measures: a preparation method of an anti-carbon dioxide corrosion inhibitor, which is prepared according to the following method:

[0009] The required amount of the first polymer, the second polymer and the modified imidazoline are mixed and compounded to obtain the anti-carbon dioxide corrosion inhibitor, wherein the first polymer is a comb structure imidazoline, the second polymer is a linear structure imidazoline, and the modified imidazoline is a primary amine modified imidazoline.

[0010] The following is a further optimization or / and improvement of the above-mentioned one of the technical solutions:

[0011] The above-mentioned first polymer is obtained according to the following method:

[0012] S1, the required amount of macromolecular petroleum acid and polyamine are mixed uniformly and then reacted to obtain intermediate one;

[0013] S2, the intermediate one and the required amount of guanidine hydrochloride are mixed uniformly and then reacted to obtain intermediate two;

[0014] S3, the required amount of monomer is added with a solvent and a chain transfer agent, and then the required amount of initiator is added and reacted to obtain intermediate three;

[0015] S4, the intermediate two, the intermediate three and the required amount of polyether amine are mixed uniformly and then reacted to obtain the first polymer.

[0016] In step S1 above, the molar ratio of macromolecular petroleum acid to polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 9 to 11 hours. The polyamine is polyethylene polyamine, and the macromolecular petroleum acid is a byproduct of petroleum refining.

[0017] In step S2 above, the molar ratio of intermediate one to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 140°C to 150°C, and the reaction time is 2.5 h to 3.5 h.

[0018] In step S3 above, the monomer is one or more of acrylic acid, maleic anhydride, and methacrylic acid; the solvent is one of methanol, ethanol, n-butanol, propylene glycol, glycerol, ethylene glycol, xylene, trimethylbenzene, dimethyl sulfoxide, and dimethylformamide; the chain transfer agent is n-dodecyl mercaptan; the initiator is one of azobisisobutyronitrile and benzoyl peroxide; the reaction temperature is 60°C to 120°C; and the reaction time is 3.5 h to 4.5 h.

[0019] In step S4 above, the polyetheramine is either D350 or D600, the reaction temperature is 100℃ to 150℃, and the reaction time is 3.5h to 4.5h.

[0020] The second polymer described above is obtained by the following method:

[0021] S11, react the required amount of intermediate one obtained in step S1 with a polycarboxylic acid to obtain the first reaction product;

[0022] S12, a chlorine-containing compound is mixed with the product of the first reaction and then subjected to a cross-linking reaction to obtain a second polymer.

[0023] In step S11 above, the polycarboxylic acid is one of adipic acid, octanoic acid and oxalic acid, the molar ratio of the polycarboxylic acid to intermediate one is 1:1 to 2, the reaction temperature is 100℃ to 150℃, and the reaction time is 3.5h to 4.5h.

[0024] In step S12 above, the chlorine-containing compound is 1,4-dichlorobenzyl, the molar ratio of the chlorine-containing compound to the first reaction product is 1:1 to 2, the reaction temperature is 70°C to 100°C, and the reaction time is 3.5h to 4.5h.

[0025] The modified imidazoline was obtained by the following method: the required amounts of intermediate I obtained in step S1, guanidine hydrochloride and primary amine were mixed and reacted to obtain the modified imidazoline.

[0026] The molar ratio of the above intermediate I, guanidine hydrochloride and primary amine is 1:1:1, the reaction temperature is 145℃ to 155℃, and the reaction time is 3.5h to 4.5h.

[0027] The primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0028] The second technical solution of the present application is achieved by the following measures: a preparation method of the anti-carbon dioxide corrosion inhibitor.

[0029] The third technical solution of the present application is achieved by the following measures: application of the anti-carbon dioxide corrosion inhibitor in corrosion protection, sterilization and scale inhibition of oil and gas wells.

[0030] The first polymer molecule has n imidazoline rings adsorbed on the stainless steel pipe, improving the adsorption capacity and erosion resistance of the corrosion inhibitor; the second polymer increases the adsorption of imidazoline; the modified imidazoline improves the hydrophobicity of the single-ring imidazoline by introducing a primary amine hydrophobic group, further inhibiting the contact of the water phase with the metal surface; meanwhile, the guanidine structure is introduced into the imidazoline structure, so that the product has strong sterilization effect; the polymer chain structure contains a carboxylic acid structure, so that it has strong complexing ability for calcium, magnesium and other cations, and can effectively inhibit the scaling problem caused by carbon dioxide. DETAILED DESCRIPTION

[0031] The present application is not limited by the following examples, and the specific implementation can be determined according to the technical solutions of the present application and the actual situation. The various chemical reagents and chemical products mentioned in the present application are all common chemical reagents and chemical products known in the prior art unless otherwise specified.

[0032] The present application will be further described below in conjunction with examples:

[0033] Example 1: The preparation method of the anti-carbon dioxide corrosion inhibitor is as follows:

[0034] The required amount of the first polymer, the second polymer and the modified imidazoline are mixed to obtain the anti-carbon dioxide corrosion inhibitor, wherein the first polymer is a comb-type structure imidazoline, the second polymer is a linear structure imidazoline, and the modified imidazoline is a primary amine modified imidazoline.

[0035] The anti-carbon dioxide corrosion inhibitor of the present application uses a macromolecular petroleum acid to prepare an imidazoline corrosion inhibitor intermediate. Due to the strong hydrophobicity of the macromolecular petroleum acid, the corrosion inhibition effect of the imidazoline corrosion inhibitor is obviously better than that of the oleic acid imidazoline corrosion inhibitor. The imidazoline corrosion inhibitor is polymerized to form a comb-type structure, and n imidazoline rings in the polymer molecule are adsorbed on the stainless steel pipe, greatly improving the adsorption capacity of the imidazoline corrosion inhibitor and the erosion resistance of the product. Meanwhile, the guanidine structure is introduced into the imidazoline structure, so that the finally obtained product has strong sterilization effect. The polymer chain structure of the obtained anti-carbon dioxide corrosion inhibitor contains a large amount of carboxylic acid (sodium) structure, so that it has strong complexing ability for calcium, magnesium and other cations.

[0036] Example 2: As an optimization of the above example, the first polymer is obtained according to the following method:

[0037] S1, a desired amount of macromolecular petroleum acid is mixed with a polyamine and then reacted to obtain intermediate one;

[0038] S2, intermediate one is mixed with a desired amount of guanidine hydrochloride and then reacted to obtain intermediate two;

[0039] S3, a desired amount of monomer is added with a solvent and a chain transfer agent, and then a desired amount of initiator is added and reacted to obtain intermediate three;

[0040] S4, intermediate two, intermediate three and a desired amount of polyetheramine are mixed and then reacted to obtain the first polymer.

[0041] The chemical reaction mechanism for obtaining intermediate one is as follows:

[0042]

[0043] Wherein, the value range of k is 2 to 10.

[0044] The chemical reaction mechanism for obtaining intermediate two is as follows:

[0045]

[0046] Wherein, the value range of k is 2 to 10.

[0047] The chemical reaction mechanism for obtaining intermediate three is as follows:

[0048]

[0049] The chemical reaction mechanism for obtaining the first polymer is as follows:

[0050]

[0051] Wherein, the value range of a, b, c and k is 2 to 10.

[0052] Example 3: As an optimization of the above example, in step S1, the molar ratio of macromolecular petroleum acid to polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250°C to 300°C, and the reaction time is 9h to 11h, wherein the polyamine is polyethylene polyamine, and the macromolecular petroleum acid is a byproduct in the petroleum refining process.

[0053] Example 4: As an optimization of the above example, in step S2, the molar ratio of intermediate one to guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 140°C to 150°C, and the reaction time is 2.5h to 3.5h.

[0054] Example 5: As an optimization of the above examples, in step S3, the monomer is one or more of acrylic acid, maleic anhydride, and methacrylic acid, the solvent is one of methanol, ethanol, n-butanol, propylene glycol, glycerol, ethylene glycol, dimethylbenzene, trimethylbenzene, dimethyl sulfoxide, and dimethylformamide, the chain transfer agent is n-dodecanethiol, the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, the reaction temperature is 60°C to 120°C, and the reaction time is 3.5h to 4.5h.

[0055] Example 6: As an optimization of the above examples, in step S4, the polyetheramine is one of D350 and D600, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

[0056] Example 7: As an optimization of the above examples, the second polymer is obtained by the following method:

[0057] S11, reacting the intermediate one obtained in step S1 with a polycarboxylic acid to obtain a first reaction product;

[0058] S12, mixing a chlorine-containing compound with the first reaction product and performing a crosslinking reaction to obtain a second polymer.

[0059] The chemical reaction mechanism for obtaining the first reaction product is as follows:

[0060]

[0061] wherein k is in the range of 2 to 10.

[0062] The chemical reaction mechanism for obtaining the second polymer is as follows:

[0063]

[0064] wherein k and d are both in the range of 2 to 10.

[0065] Example 8: As an optimization of the above examples, in step S11, the polycarboxylic acid is one of adipic acid, suberic acid, and oxalic acid, the molar ratio of the polycarboxylic acid to the intermediate one is 1:1 to 2, the reaction temperature is 100°C to 150°C, and the reaction time is 3.5h to 4.5h.

[0066] Example 9: As an optimization of the above examples, in step S12, the chlorine-containing compound is 1,4-p-dichlorobenzyl, the molar ratio of the chlorine-containing compound to the first reaction product is 1:1 to 2, the reaction temperature is 70°C to 100°C, and the reaction time is 3.5h to 4.5h.

[0067] Example 10: As an optimization of the above examples, the modified imidazoline is obtained by the following method: the intermediate one obtained in step S1, guanidine hydrochloride and primary amine are mixed and reacted in a desired amount to obtain the modified imidazoline.

[0068] The chemical reaction mechanism for obtaining the modified imidazoline is as follows:

[0069]

[0070] wherein the value range of k and d is 2 to 10.

[0071] Example 11: As an optimization of the above examples, the molar ratio of the intermediate one, guanidine hydrochloride and primary amine is 1:1:1, the reaction temperature is 145°C to 155°C, and the reaction time is 3.5h to 4.5h.

[0072] Example 12: As an optimization of the above examples, the primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

[0073] Example 13: The anti-carbon dioxide corrosion inhibitor prepared by the preparation method of the anti-carbon dioxide corrosion inhibitor.

[0074] Example 14: The application of the anti-carbon dioxide corrosion inhibitor in corrosion protection, sterilization and scale inhibition of oil and gas wells.

[0075] Example 15: The preparation method of the anti-carbon dioxide corrosion inhibitor, which is carried out according to the following steps:

[0076] First step, add 350kg (1kmol) of macromolecular petroleum acid (molecular weight 350) and 439kg (1kmol) of polyethylene polyamine (molecular weight 439) into a reaction kettle, mix uniformly, slowly warm up to 280°C, reflux for 10h to obtain intermediate one;

[0077] Second step, mix the intermediate one with 95.5kg (1kmol) of guanidine hydrochloride uniformly, control the temperature at 150°C and react for 3h to obtain intermediate two;

[0078] Third step, take 200kg of solvent (ethanol), add 100kg of monomer (acrylic acid) and 2kg of chain transfer agent (n-dodecanethiol), control the temperature at 80°C, add 0.4kg of initiator (azobisisobutyronitrile) (add in 4 times, 0.1kg / h), react for 4h, then remove the solvent by vacuum dehydration to obtain intermediate three;

[0079] Fourth step, mix 884.5kg of intermediate two and 302kg of intermediate three uniformly, add 50kg of polyether amine (D350), control the temperature at 150°C and react for 4h to obtain the first polymer (comb-shaped structure imidazoline);

[0080] Fifth step, take 789 kg of intermediate one and 73 kg of adipic acid (0.5 kmol), control temperature 150℃ for 4h, then add 1,4-p-dichlorobenzyl 87.5kg (0.5 kmol), 80℃ for 4h, to obtain the second polymer (linear structure imidazoline);

[0081] Sixth step, take 789 kg of intermediate one, 95.5 kg of guanidine hydrochloride, 241.5 kg of hexadecyl primary amine, control temperature 150℃ for 4h, to prepare modified imidazoline by reaction;

[0082] Seventh step, mix the first polymer, the second polymer, and the modified imidazoline according to the mass ratio of 9:0.5:0.5, stir uniformly, to obtain the anti-carbon dioxide corrosion inhibitor.

[0083] Example 16: The preparation method of the anti-carbon dioxide corrosion inhibitor is different from that of example 15 in that:

[0084] In the fourth step, 50 kg of polyetheramine (D350) is replaced by 50 kg of polyetheramine (D600);

[0085] The rest of the process is the same.

[0086] Example 17: The preparation method of the anti-carbon dioxide corrosion inhibitor is different from that of example 15 in that:

[0087] In the third step, the monomer is methacrylic acid;

[0088] The rest of the process is the same.

[0089] Example 18: The preparation method of the anti-carbon dioxide corrosion inhibitor is different from that of example 15 in that:

[0090] In the third step, the initiator is dibenzoyl peroxide;

[0091] The rest of the process is the same.

[0092] Example 19: The preparation method of the anti-carbon dioxide corrosion inhibitor is different from that of example 15 in that:

[0093] In the sixth step, 241.5 kg of hexadecyl primary amine is replaced by 185.3 kg of dodecyl primary amine;

[0094] The rest of the process is the same.

[0095] Example 20: The preparation method of the anti-carbon dioxide corrosion inhibitor is different from that of example 15 in that:

[0096] In the fifth step, 73 kg of adipic acid is replaced by 87 kg of octanoic acid;

[0097] The rest of the process is the same.

[0098] The anti-carbon dioxide corrosion inhibitor obtained according to Examples 15 to 20 is subjected to performance test evaluation:

[0099] (1) Bactericidal performance evaluation

[0100] According to SY / T 5890 "Bactericide Performance Evaluation Method", the bactericidal effect of the anti-carbon dioxide corrosion inhibitor on sulfate-reducing bacteria, iron bacteria and saprophytic bacteria is determined by the absolute trace dilution method, and the dosing concentration of the anti-carbon dioxide corrosion inhibitor of the present application is 1%.

[0101] Comparative Example 1: A single guanidine bactericide is used.

[0102] Comparative Example 2: A composite bactericide containing oleic acid imidazoline, polyacrylic acid and single guanidine is used as a bactericide.

[0103] The experimental results of the bacterial test bottle SRB (sulfate-reducing bacteria) reading, IB (iron bacteria) reading and TGB (saprophytic bacteria) reading are shown in Table 1.

[0104] Table 1

[0105] .

[0106] As can be seen from Table 1, the bactericidal performance of the anti-carbon dioxide corrosion inhibitor of the present application is slightly better than that of the single guanidine bactericide on the market, but is significantly better than that of the composite bactericide containing single guanidine, because when multiple agents are compounded in the composite bactericide containing single guanidine, there is incompatibility between the agents, resulting in poor performance.

[0107] (2) Inhibition experiment

[0108] Referring to the SYT5273 Oilfield Produced Water Reinjection Water Inhibitor Performance Evaluation Method Standard, six 1L bottles with stoppers are taken, oilfield water source well water and 1% anti-carbon dioxide corrosion inhibitor (Examples 15 to 20) are added respectively, constant volume is made to 1L, N80 hanging piece (outer size is 40mmx13mmx2mm, a round hole is drilled in the middle position at a distance of 5mm from the edge line at one end, the surface area is 12cm 2 ), CO2 and H2S are introduced to saturation to simulate the working conditions in the acidic oil and gas well. And in the constant temperature oven at 90℃, it is placed for 14d, the hanging piece is taken out, the corrosion products on the surface of the hanging piece are cleaned, cold air drying, weighing, calculating the corrosion rate of the steel piece according to formula (1), the results are shown in Table 2.

[0109]

[0110] Wherein, γ c is the corrosion rate, unit is mm / a; ω0 is the initial mass of the hanging piece, unit is g; ω1 is the mass of the hanging piece at the end of the experiment, unit is g; S is the surface area of the hanging piece, unit is cm 2; t is the reaction time, in h; p is g / cm 3 .

[0111] Blank example: CO2 and H2S are introduced into the oilfield water source well water until saturation, and no anti-carbon dioxide corrosion inhibitor is added, and the remaining steps are consistent with the above steps, and the results are shown in Table 2.

[0112] Comparative example 1: using imidazoline oleate as the corrosion inhibitor.

[0113] Comparative example 2: using a composite agent containing imidazoline oleate, polyacrylic acid, and monoguanidine as the corrosion inhibitor.

[0114] Table 2

[0115] .

[0116] As can be seen from Table 2, the anti-carbon dioxide corrosion inhibitor has excellent corrosion inhibition performance, and the corrosion inhibition performance is slightly better than or close to that of imidazoline oleate, but is significantly better than that of the composite agent containing imidazoline oleate. The reason is that when multiple agents are compounded in the composite agent containing imidazoline oleate, the agents are not compatible, resulting in poor performance.

[0117] (3) Scale inhibition experiment

[0118] According to the standard SY / T5673-93 "Performance Evaluation Method for Scale Inhibitors for Oilfields", the calcium carbonate scale inhibition rate is required to be ≥ 90%, and the experimental results are shown in Table 3.

[0119] Comparative example 1: using polyacrylic acid as the scale inhibitor.

[0120] Comparative example 2: using a composite agent containing imidazoline oleate, polyacrylic acid, and monoguanidine as the scale inhibitor.

[0121] Table 3

[0122] .

[0123] As can be seen from Table 3, the anti-carbon dioxide corrosion inhibitor has similar scale inhibition performance to that of the polyacrylic acid scale inhibitor, but can meet the on-site requirements (the standard requires ≥ 90%); however, the scale inhibition performance is significantly better than that of the composite agent containing polyacrylic acid. The reason is that when multiple agents are compounded in the composite agent containing polyacrylic acid, the agents are not compatible, resulting in poor performance. The present agent can effectively solve the problem of agent incompatibility.

[0124] Through the corrosion, scale inhibition, and sterilization experiments, it can be seen that the anti-carbon dioxide corrosion inhibitor has good corrosion inhibition effect under simulated conditions, with a corrosion inhibition rate of less than 0.05 mm / a, which is much lower than the corresponding industry standard. The scale inhibition rate and sterilization rate meet the industry standard, and the anti-carbon dioxide corrosion inhibitor has good protection function for the inner wall of the casing in the annular space and the outer wall of the oil and gas pipeline in the acidic environment, prolonging the service life and ensuring the safety of oilfield production.

[0125] In summary, the anti-carbon dioxide corrosion inhibitor has strong adsorption, can be effectively adsorbed on the surface of a steel sheet, thereby reducing the corrosion of the metal, and also has certain bactericidal and scale inhibition performance.

[0126] To sum up, the n imidazoline rings in the first polymer molecule are adsorbed on the stainless steel pipe, the adsorption capacity and the erosion resistance of the corrosion inhibitor are improved, the second polymer increases the adsorption of imidazoline, the modified imidazoline improves the hydrophobicity of the single-ring imidazoline by introducing a primary amine hydrophobic group, further inhibits the contact of the water phase with the metal surface, the guanidine structure is introduced into the imidazoline structure, so that the product has strong bactericidal efficacy, the polymer chain structure contains a carboxylic acid structure, so that it has strong complexing ability for calcium, magnesium and other cations, and can effectively inhibit the scaling problem caused by carbon dioxide.

[0127] The above technical features constitute an embodiment of the present application, which has strong adaptability and implementation effect, and unnecessary technical features can be added or reduced according to actual needs to meet the needs of different situations.

Claims

1. A method for preparing an anti-carbon dioxide corrosion inhibitor, characterized by The anti-carbon dioxide corrosion inhibitor is prepared by compounding a first polymer, a second polymer and a modified imidazoline in a required amount, wherein the first polymer is a comb structure imidazoline, the second polymer is a linear structure imidazoline, and the modified imidazoline is a primary amine modified imidazoline, The first polymer is prepared by the following method: S1, a required amount of macromolecular petroleum acid is uniformly mixed with a polyamine, and then reacted to obtain an intermediate one, wherein the molar ratio of the macromolecular petroleum acid to the polyamine is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 250 to 300 DEG C, the reaction time is 9 to 11 hours, the polyamine is a polyethylene polyamine, and the macromolecular petroleum acid is a by-product in the petroleum refining process; S2, the intermediate one is uniformly mixed with a required amount of guanidine hydrochloride, and then reacted to obtain an intermediate two, wherein the molar ratio of the intermediate one to the guanidine hydrochloride is 0.9 to 1.1:0.9 to 1.1, the reaction temperature is 140 to 150 DEG C, and the reaction time is 2.5 to 3.5 hours; S3, a solvent and a chain transfer agent are added to a required amount of monomer, and then a required amount of an initiator is added to react to obtain an intermediate three, wherein the monomer is one or more of acrylic acid, maleic anhydride and methacrylic acid, the solvent is one of methanol, ethanol, n-butanol, propylene glycol, glycerol, ethylene glycol, dimethylbenzene, trimethylbenzene, dimethyl sulfoxide and dimethyl formamide, the chain transfer agent is n-dodecanethiol, and the initiator is one of azobisisobutyronitrile and dibenzoyl peroxide, the reaction temperature is 60 to 120 DEG C, and the reaction time is 3.5 to 4.5 hours; S4, the intermediate two, the intermediate three and a required amount of polyether amine are uniformly mixed and then reacted to obtain the first polymer, wherein the polyether amine is one of D350 and D600, the reaction temperature is 100 to 150 DEG C, and the reaction time is 3.5 to 4.5 hours; The second polymer is prepared by the following method: S11, a required amount of the intermediate one obtained in step S1 is reacted with a polybasic acid to obtain a first reaction product, wherein the polybasic acid is one of adipic acid, suberic acid and oxalic acid, the molar ratio of the polybasic acid to the intermediate one is 1:1 to 2, the reaction temperature is 100 to 150 DEG C, and the reaction time is 3.5 to 4.5 hours; S12, a chlorine-containing compound is mixed with the first reaction product to perform a cross-linking reaction to obtain the second polymer, wherein the chlorine-containing compound is 1,4-p-dichlorobenzene, the molar ratio of the chlorine-containing compound to the first reaction product is 1:1 to 2, the reaction temperature is 70 to 100 DEG C, and the reaction time is 3.5 to 4.5 hours; The modified imidazoline is prepared by the following method: the intermediate one obtained in step S1, guanidine hydrochloride and a primary amine are mixed and then reacted to obtain the modified imidazoline, wherein the molar ratio of the intermediate one, the guanidine hydrochloride and the primary amine is 1:1:1, the reaction temperature is 145 to 155 DEG C, and the reaction time is 3.5 to 4.5 hours.

2. The method for preparing the carbon dioxide corrosion inhibitor according to claim 1, characterized in that... The primary amine is one of dodecyl primary amine, tetradecyl primary amine, hexadecyl primary amine and octadecyl primary amine.

3. An anti-carbon dioxide corrosion inhibitor prepared by the preparation method according to claim 1 or 2.

4. The use of the anti-carbon dioxide corrosion inhibitor according to claim 3 in corrosion protection, bactericidal, and scale inhibition of oil and gas wells.

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