Solid iron ion stabilizer for acidizing and fracturing and method for preparing the same

Abstract

The application belongs to the technical field of oil exploitation, and particularly relates to a solid iron ion stabilizer for acidification and fracturing and a preparation method thereof. The preparation method is as follows: 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, ethanol and ethylenediaminetetracetic acid are added into a four-necked flask provided with a condenser, the pH value is adjusted, stirring and dissolution are carried out, heating and heat preservation reaction are carried out, the remaining ethanol is distilled out under reduced pressure, a mixed solution is obtained, cooling is carried out, solid is precipitated, filtration is carried out, and the product iron ion stabilizer is obtained after overnight drying. The iron ion stabilizer has the advantages of strong iron ion stabilization capacity, good effect and high temperature resistance, and the stable iron ion retention rate is more than 97% after 4 hours of constant temperature at 160 DEG C.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, and specifically relates to a solid iron ion stabilizer for acid fracturing and its preparation method. Background Technology

[0002] Acidizing is one of the main methods for enhancing oil and gas well production. It can remove blockages in pores or fractures, or improve existing pores and fractures in the formation, increasing formation permeability and thus achieving the goal of increasing production and injection. During acidizing operations in oil and gas fields, the high concentration of acid solution dissolves iron compounds in equipment and tubing during agitation and pumping. Although corrosion inhibitors are added, corrosion of the pipe walls and dissolution of iron scale cannot be completely avoided. The acid solution may also react with iron-bearing minerals and clay minerals in the formation, resulting in the presence of Fe in the solution. 3+ and Fe 2+ Iron ions are present in the acid solution, remaining in an ionic state. As the acid continues to react with the formation rocks, the effective concentration of the acid gradually decreases, and the pH value increases. When the pH value of the residual acid rises and reaches a certain value, ferric hydroxide precipitate will form, severely clogging the newly opened flow channels created during acidizing. Furthermore, iron ions enhance the stability of the residual acid emulsion, making acid removal more difficult and exacerbating the formation of acid sludge, causing further damage to the oil reservoir.

[0003] To prevent the formation of iron precipitates when the acid solution becomes residual acid, iron ion stabilizers are often added to the acid solution in acidification technology. This prevents the formation of gel-like iron hydroxide precipitates when the acid solution becomes residual acid, thus preventing damage to the oil and gas reservoir and improving the acidification effect.

[0004] Iron ion stabilizers can prevent Fe from forming through multiple mechanisms such as complexation, coordination, reduction, and dispersion. 3+ Reprecipitation prevents formation damage and improves the yield of acidizing operations.

[0005] CN104479656A discloses a viscous acid solution for acidification treatment, which is composed of the following components by weight percentage: hydrochloric acid 19.9-25.0%, hydrofluoric acid 1.0-7.5%, viscous agent 5-7%, acidification corrosion inhibitor 1-2%, iron ion stabilizer 0.1-0.5%, demulsifier 0.3-0.4%, clay stabilizer 1-1.5%, acidification miscible solvent 1-2%, and the balance being water. This invention provides a viscous acid solution with self-directing and diverting properties, enabling uniform acid distribution through general acidification. However, the main principle of this invention in stabilizing iron ions is to reduce iron ions by inhibiting the corrosion of metallic iron, which may affect the formation of Fe. 3+ The stability effect is poor.

[0006] CN105295887A discloses a high-performance iron ion stabilizer for acidizing operations and its preparation method. During acidizing, the H+ concentration in the acid solution continuously decreases while the pH value continuously increases, causing iron, which originally exists in an ionic state, to precipitate, blocking oil and gas seepage channels in the formation, causing secondary pollution, and leading to a decrease in recovery rate. Therefore, an iron ion stabilizer needs to be added to ensure that iron always exists in a soluble state in the residual acid. The technical solution of this invention is as follows: sodium isoascorbate, NTA, citric acid, disodium EDTA, and water are added to a container in proportion, with the following mass fractions: sodium isoascorbate 5%–16%, NTA 1%–3%, citric acid 2%–5%, disodium EDTA 2%–5%, and the remainder being water; the mixture is stirred at a controlled temperature to ensure complete dissolution, cooled to room temperature, transferred to a volumetric flask, and diluted to volume to obtain the iron ion stabilizer. This iron ion stabilizer has both chelating and reducing abilities, strong iron stabilization capacity, and low production cost. However, the iron ion stabilizer of this invention has an iron ion stabilization capacity of only about 40 mg / ml, which is poor. Summary of the Invention

[0007] This invention addresses the shortcomings of the prior art by providing a solid iron ion stabilizer for acid fracturing and its preparation method. The iron ion stabilizer of this invention has the advantages of strong iron ion stabilization ability, good effect, and high temperature resistance; after being kept at 160°C for 4 hours, the iron ion retention rate reaches over 97%.

[0008] One objective of this invention is to disclose a method for preparing a solid iron ion stabilizer for acid fracturing, the specific steps of which are as follows:

[0009] (1) Add 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, ethanol, and ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 60-65℃, and maintain the temperature for reaction. During the reaction, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0010] (2) Distill the above mixture under reduced pressure, and add distilled water to the remaining small amount of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0011] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 80-90°C overnight to obtain the product iron ion stabilizer.

[0012] In this invention, preferably, the amount of ethylenediaminetriacetic acid used is 0.9-1.5 mol based on 1 mole of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid.

[0013] More preferably, based on 1 mole of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, the amount of ethylenediaminetriacetic acid used is 1-1.4 mol.

[0014] In this invention, preferably, the weight ratio of ethanol to 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid in step (1) is 12-15:1.

[0015] In this invention, preferably, the heat preservation reaction time in step (1) is 2-4 hours.

[0016] In this invention, preferably, the weight ratio of the small amount of ethanol to 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid in step (2) is 3-4:1.

[0017] In this invention, preferably, the weight ratio of distilled water to 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid in step (2) is 8-10:1.

[0018] The reaction equation for the synthesis of the iron ion stabilizer of the present invention is as follows:

[0019]

[0020] Another objective of this invention discloses a solid iron ion stabilizer for acid fracturing, the molecular structural formula of which is as follows:

[0021]

[0022] The solid iron ion stabilizer for acid fracturing of the present invention contains 7 carboxyl functional groups, and 4 of the carboxyl groups are cyclic structures, which have a strong chelating effect and can significantly reduce free iron ions, thereby preventing iron ions from precipitating out of the solution; the tertiary amine contains 6 tertiary amine functional groups, which can form coordinate bonds with iron ions, further reducing free iron ions; the reaction substrates are all iron ion stabilizers, and a small amount of unreacted residue in the product will still play an auxiliary role in stabilizing iron ions.

[0023] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0024] (1) The solid iron ion stabilizer for acid fracturing of the present invention has a strong ability to stabilize iron ions, with a maximum of 202 mg / ml;

[0025] (2) The solid iron ion stabilizer for acid fracturing of the present invention has strong temperature resistance. After being kept at 160°C for 4 hours, the stable iron ion retention rate reaches more than 97%.

[0026] (3) The solid iron ion stabilizer for acid fracturing of the present invention has a good effect on stabilizing iron ions. After the acidizing fluid of oil well with an iron content of 180 mg / L is stabilized, the free iron ion content is 0 mg / L. Attached Figure Description

[0027] Figure 1 Colorimetric tube diagram for testing iron ion content in oil well acidizing fluid diluted 20 times;

[0028] Figure 2 Colorimetric tube diagram for testing iron ion content in oil well acidizing fluid added according to Example 1;

[0029] Figure 3 Colorimetric tube diagram for testing iron ion content in oil well acidizing fluid (Example 9);

[0030] Figure 4 Colorimetric tube diagram for testing the iron ion content of comparative samples added to oil well acidizing fluid. Detailed Implementation

[0031] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0032] Example 1

[0033] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 75.6 g of ethanol, and 9 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 60°C, and keep the reaction at this temperature for 2 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0034] (2) Distill the above mixture under reduced pressure, and add 50.4g of distilled water to the remaining 18.9g of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0035] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 80°C overnight to obtain the product iron ion stabilizer.

[0036] Example 2

[0037] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 84.3 g of ethanol, and 15 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 65°C, and keep the reaction at this temperature for 2.5 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0038] (2) Distill the above mixture under reduced pressure, and add 58.6g of distilled water to the remaining 21.4g of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0039] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 90°C overnight to obtain the product iron ion stabilizer.

[0040] Example 3

[0041] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 92.4 g of ethanol, and 10 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 62°C, and keep the reaction at this temperature for 2 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0042] (2) Distill the above mixture under reduced pressure, and add 51.8g of distilled water to the remaining 21.6g of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0043] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 85°C overnight to obtain the product iron ion stabilizer.

[0044] Example 4

[0045] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 94.5 g of ethanol, and 14 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 63°C, and keep the reaction at this temperature for 3 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0046] (2) Distill the above mixture under reduced pressure, and add 63g of distilled water to the remaining 19.8g of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0047] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 85°C overnight to obtain the product iron ion stabilizer.

[0048] Example 5

[0049] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 77.7 g of ethanol, and 11 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 61°C, and keep the reaction at this temperature for 3.5 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0050] (2) Distill the above mixture under reduced pressure, and add 60.5g of distilled water to the remaining 25.2g of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0051] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 82°C overnight to obtain the product iron ion stabilizer.

[0052] Example 6

[0053] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 80 g of ethanol, and 13.5 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 64°C, and keep the reaction at this temperature for 4 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0054] (2) Distill the above mixture under reduced pressure, and add 57.4g of distilled water to the remaining 19.4g of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0055] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 87°C overnight to obtain the product iron ion stabilizer.

[0056] Example 7

[0057] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 85.7 g of ethanol, and 11.8 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 62°C, and keep the reaction at this temperature for 4 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0058] (2) Distill the above mixture under reduced pressure, and add 60g of distilled water to the remaining 23.3g of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0059] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 83°C overnight to obtain the product iron ion stabilizer.

[0060] Example 8

[0061] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 89.8 g of ethanol, and 12.7 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 65°C, and keep the reaction at this temperature for 3.5 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0062] (2) Distill the above mixture under reduced pressure, and add 58g of distilled water to the remaining 24.4g of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture.

[0063] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 85°C overnight to obtain the product iron ion stabilizer.

[0064] Example 9

[0065] (1) Add 10 mmol of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, 91.7 g of ethanol, and 12.5 mmol of ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 60°C, and keep the reaction at this temperature for 4 h. During this period, sodium hydroxide solution is added several times to maintain the pH at 7.5-8 to obtain a mixed solution.

[0066] (2) Distill the above mixture under reduced pressure, add 58.6g of distilled water to the remaining 25g of ethanol, adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture;

[0067] (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 88°C overnight to obtain the product iron ion stabilizer.

[0068] Example 10

[0069] The ability of the solid iron ion stabilizer for acid fracturing of the present invention (Examples 1-9) to stabilize iron ions (N1) was tested, and the evaluation method was performed in accordance with the method in SY / T 6571-2012 "Performance Evaluation Method of Iron Ion Stabilizer for Acidizing".

[0070] A comparative experiment was conducted using HJZ-801, an iron ion stabilizer from Kaifeng Hengju Biotechnology Co., Ltd. The test results are shown in Table 1.

[0071] As can be seen from Table 1:

[0072] The solid iron ion stabilizers for acid fracturing of the present invention (Examples 1-9) all have an iron ion stabilization capacity of over 180 mg / ml, with the highest reaching 202 mg / ml (Example 9). In contrast, the iron ion stabilization capacity of HJZ-801 iron ion stabilizer from Kaifeng Hengju Biotechnology Co., Ltd. is 122 mg / ml, which is significantly lower than that of the present invention.

[0073] Example 11

[0074] The ability of the solid iron ion stabilizer for acid fracturing of the present invention (Examples 1-9) to stabilize iron ions at high temperatures was tested. The evaluation method referred to SY / T 6571-2012 "Performance Evaluation Method for Iron Ion Stabilizers for Acidizing Fracturing," and was performed according to method 6.2 of the standard. Stabilizer samples were prepared, placed in a 160℃ oven for 4 hours, and then removed. The iron ion stabilization ability N was tested according to the standard method. 2。

[0075] A comparative experiment was conducted using HJZ-801, an iron ion stabilizer from Kaifeng Hengju Biotechnology Co., Ltd.

[0076] Calculate the high-temperature stable iron ion retention rate S:

[0077] S = (N2 / N1) × 100%

[0078] The test results are shown in Table 1.

[0079] Table 1. Test results of iron ion stabilization ability at room temperature and 160℃

[0080] Iron ion stabilizer <![CDATA[N1,mg / g]]> <![CDATA[N2,mg / g]]> S，％ Example 1 185 182 98.4 Example 2 188 186 98.9 Example 3 190 189 99.5 Example 4 191 189 99.0 Example 5 195 192 98.5 Example 6 194 190 97.9 Example 7 198 195 98.5 Example 8 200 197 98.5 Example 9 202 199 98.5 Comparative Example 122 97 83.6

[0081] As can be seen from Table 1:

[0082] The solid iron ion stabilizer for acid fracturing of the present invention (Examples 1-9) maintained a stable iron ion retention rate of over 97% after being kept at 160°C for 4 hours, with the highest reaching 99.5%. In contrast, the iron ion retention rate of the comparative iron ion stabilizer HJZ-801 from Kaifeng Hengju Biotechnology Co., Ltd. was 83.6%, significantly lower than that of the present invention. The solid iron ion stabilizer for acid fracturing of the present invention exhibits strong temperature resistance.

[0083] Example 12

[0084] Take oil well M from a certain oil production plant in Shengli Oilfield 12 Acidification solution.

[0085] The following experiment was conducted:

[0086] 1) Dilute the oil well acidizing fluid 20 times with distilled water, adjust the pH to 2.2 with 5wt% sodium carbonate solution, and test the iron ion content using a standard colorimetric tube. The test results are shown below. Figure 1 .

[0087] 2) Adjust the pH of the oil well acidizing fluid to 2.2 using a 5wt% sodium carbonate solution. Add 0.15g of each of the following solutions to 100ml of the pH 2.2 oil well acidizing fluid: Example 1, Example 9, and Comparative Example, respectively. Stir well and test the iron ion content using a standard colorimetric tube. The test results are shown in [Figure number missing]. Figure 2 , Figure 3 , Figure 4 .

[0088] from Figures 1-4 It can be seen that:

[0089] The iron ion content of the oil well acidizing fluid is: 9 × 20 = 180 mg / L.

[0090] The iron ion content in Examples 1 and 9 is 0 mg / L.

[0091] The free iron ion content in the comparative example was 1.5 mg / L.

[0092] The solid iron ion stabilizer for acid fracturing of the present invention not only has a strong ability to stabilize iron ions, but also has a good effect on stabilizing iron ions.

[0093] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a solid iron ion stabilizer for acid fracturing, characterized in that, The specific steps of the preparation method are as follows: (1) Add 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, ethanol, and ethylenediaminetriacetic acid to a four-necked flask equipped with a condenser. Adjust the pH to 7.5-8 with sodium hydroxide solution, stir to dissolve, heat to 60-65℃, and maintain the temperature for reaction. During the reaction, add sodium hydroxide solution several times to maintain the pH at 7.5-8 to obtain a mixed solution. (2) Distill the above mixture under reduced pressure, and add distilled water to the remaining small amount of ethanol. Adjust the pH to 2-2.5 with hydrochloric acid, and distill off the remaining ethanol under reduced pressure to obtain the mixture. (3) Cool the mixture in step (2) to below 5°C with ice water to precipitate solid, filter, dry at 80-90°C overnight to obtain the product iron ion stabilizer; The molecular structural formula of the iron ion stabilizer is as follows: 。 2. The method for preparing a solid iron ion stabilizer for acid fracturing according to claim 1, characterized in that, Based on 1 mole of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, the amount of ethylenediaminetriacetic acid used is 0.9-1.5 mol.

3. The method for preparing a solid iron ion stabilizer for acid fracturing according to claim 2, characterized in that, Based on 1 mole of 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid, the amount of ethylenediaminetriacetic acid used is 1-1.4 mol.

4. The method for preparing a solid iron ion stabilizer for acid fracturing according to claim 1, characterized in that, The weight ratio of ethanol to 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid in step (1) is 12-15:

1.

5. The method for preparing a solid iron ion stabilizer for acid fracturing according to claim 1, characterized in that, The heat preservation reaction time mentioned in step (1) is 2-4 hours.

6. The method for preparing a solid iron ion stabilizer for acid fracturing according to claim 1, characterized in that, The weight ratio of the small amount of ethanol mentioned in step (2) to 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid is 3-4:

1.

7. The method for preparing a solid iron ion stabilizer for acid fracturing according to claim 1, characterized in that, The weight ratio of distilled water to 2-[2-[[4-[(2-bromoacetyl)amino]phenyl]methyl]-4,7,10-tris(carboxymethyl)-1,4,7,10-tetraazacyclododec-1-yl]acetic acid in step (2) is 8-10:

1.

8. A solid iron ion stabilizer for acid fracturing, characterized in that, The molecular structural formula of the iron ion stabilizer is as follows: 。

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