Complexing agents, processes for their preparation and iron ion stabilizers

Abstract

The present application relates to the oil field chemical technical field, it is a kind of complexing agent and its preparation method and a kind of iron ion stabilizer, the complexing agent is prepared according to the following steps: step one, organic amine is dissolved in reaction solvent, add unsaturated ester, reflux reaction, obtain first mixed solution;Step two, add alkali to the first mixed solution, continue to react, after removing reaction solvent, obtain complexing agent.The complexing agent is used as raw material, the present application provides a kind of iron ion stabilizer, which is composed of complexing agent, reducing agent and pH regulator, the synergistic effect of the three, greatly improve the iron stability and temperature resistance, meet the needs of high-temperature reservoir acidification reconstruction.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil field chemistry, and is a complexing agent, a preparation method and application thereof, and an iron ion stabilizer using the complexing agent as raw material. BACKGROUND

[0002] As one of the main means for increasing production of oil and gas wells, acidizing and fracturing can effectively remove pore or fracture blockage, and can also improve the original pores and fractures of the formation, thereby increasing the reservoir permeability and achieving the purpose of increasing production and injection. During the acidizing process, acid and iron-containing minerals in the formation interact with surface equipment, downhole pipe column, etc., and inevitably produce iron ions (Fe 3+ and Fe 2+ ). As H + in the acid is continuously consumed, the pH value of the acid is continuously increased, and the originally existing iron ions in the form of ions begin to generate precipitates, block the oil and gas seepage channels, cause secondary damage to the reservoir, and affect the acidizing effect. In theory, Fe 3+ begins to precipitate when pH>2, and completely precipitates when pH reaches 3-5; Fe 2+ only appears obvious precipitation when pH reaches 7-8. The residual acid pH value generally needs to be controlled below 6, less than the Fe 2+ precipitation value, so in the actual construction process, only the precipitation problem of Fe 3+ needs to be considered. The application of iron ion stabilizer can ensure that the iron ion always exists in a soluble state in the residual acid to a certain extent.

[0003] The current iron ion stabilizer is mainly divided into three categories of reducing agent, complexing agent and their combination, among which the reducing agent mainly uses sulfite, isoascorbic acid, etc., and its purpose is to convert Fe 3+ which is easy to generate precipitates into Fe 2+ which is not easy to generate precipitates, but Fe 2+ is easy to be converted into Fe 3+ under the high temperature condition of the oil reservoir.Therefore, it is not suitable for high temperature reservoir; complexing agent mainly uses citric acid, ethylenediamine tetraacetic acid, nitrilotriacetic acid, acetic acid, etc., among which ethylenediamine tetraacetic acid is expensive and has low solubility, and is rarely used; nitrilotriacetic acid has the problem of forming calcium precipitate; acetic acid has poor temperature resistance, and is usually only suitable for 66℃ formation; citric acid is cheap, has high solubility and good temperature resistance (it is reported that the temperature resistance of citric acid complexing iron reaches 204℃), and is an ideal iron ion stabilizer; however, high concentration of citric acid is easy to generate calcium citrate precipitate to plug the formation, and in the case that the concentration of calcium ion in the formation is difficult to change, only the concentration of citric acid can be adjusted, which limits the concentration of citric acid and cannot be too high, thereby resulting in small amount of iron ion stabilizing when using single citric acid as iron ion complexing agent, and it is difficult to meet the industrial production demand. Many existing iron ion stabilizers have performance defects.

[0004] The Chinese patent document with publication number CN103436247A discloses an augmented acidizing fluid for water injection, and the formula is: 10-14% hydrochloric acid, 1-4% hydrofluoric acid, 1-4% acidification retarder, 1-2% acidification corrosion inhibitor, 0.1-0.5% iron ion stabilizer, 0.2-1% demulsification cleanup agent, 1-2% clay stabilizer, and the rest is water. The main principle of the action of the acidizing fluid is to slow down the corrosion, thereby reducing Fe(OH)3precipitate, and the generated Fe(OH)3is difficult to plug the formation. 3+ The stabilizing effect is poor.

[0005] The Chinese patent document with publication number CN1067912A discloses an acid liquid iron ion stabilizer, and the formula is: ascorbic acid: glucose: calcium 2-ketoglucuronate in a weight ratio of 100:5-120:5-120. The ascorbic acid, glucose and calcium 2-ketoglucuronate have reducing property and chelating property, and it is proved that the ability of the acid liquid iron ion stabilizer is obviously higher than that of single chelating agent and reducing agent. However, the iron ion stabilizer has insufficient temperature resistance.

[0006] The Chinese patent document with publication number CN105295887A discloses an iron ion stabilizer with excellent performance for acidizing operation and a preparation method thereof. The technical scheme of the invention is: adding sodium erythorbate, nitrilotriacetic acid, citric acid, ethylenediamine tetraacetic acid disodium salt and water into a container in proportion, and the mass fraction of each component is: sodium erythorbate 5-16%, nitrilotriacetic acid 1-3%, citric acid 2-5% and ethylenediamine tetraacetic acid disodium salt 2-5%, and the rest is water; controlling a certain temperature and stirring to completely dissolve, cooling to room temperature, transferring to a volumetric flask and constant volume, and the iron ion stabilizer is obtained. The iron ion stabilizer has chelating ability and reducing ability, has strong iron stabilizing ability, and has low production cost. However, the iron ion stabilizing capacity of the invention is only about 40mg / ml, and the iron ion stabilizing capacity is low. SUMMARY

[0007] The application provides a complexing agent and a preparation method and application thereof, and an iron ion stabilizer, which overcomes the defects of the prior art, and effectively solves the problem that the iron ion stabilizer cannot meet the high-temperature reservoir acidification modification requirement in terms of iron stabilizing performance and temperature resistance.

[0008] One of the technical solutions of the application is realized by the following measures: a preparation method of a complexing agent, which is performed in the following steps:

[0009] In step one, the organic amine is dissolved in a reaction solvent, and an unsaturated ester is added for reflux reaction to obtain a first mixed solution;

[0010] In step two, a base is added to the first mixed solution for continuous reaction, and after the reaction solvent is removed, the complexing agent is obtained;

[0011] The organic amine is one or more of ethylenediamine, propylenediamine, ethanolamine, diethanolamine, tris(hydroxymethyl)aminomethane, diethylenetriamine, triethylenetetramine, polyethylene polyamine and polyethyleneimine.

[0012] The unsaturated ester is one or more of dimethyl maleate, diethyl maleate, dimethyl itaconate, diethyl itaconate, dimethyl citraconate and diethyl citraconate.

[0013] The following is a further optimization or / and improvement of one of the above technical solutions:

[0014] The reaction solvent is anhydrous methanol or anhydrous ethanol.

[0015] The base is one or more of sodium hydroxide, potassium hydroxide and sodium methoxide.

[0016] The molar ratio of the unsaturated ester to the active hydrogen in the organic amine is 1 to 1.2, and the molar ratio of the base to the unsaturated ester is 2:1.

[0017] In step one, the reflux reaction temperature is 60-80 DEG C, and the reaction time is 6-24 h.

[0018] In step two, the reaction temperature is 60-80 DEG C, and the reaction time is 2-6 h.

[0019] The second technical solution of the application is realized by the following measures: the complexing agent prepared by the preparation method of the complexing agent in one of the technical solutions.

[0020] The third technical solution of the application is realized by the following measures: the application of the complexing agent in an acidizing fracturing aid.

[0021] The fourth technical scheme of the present application is realized by the following measures: an iron ion stabilizer, raw materials including, by mass fraction: a complexing agent 10 parts, a reducing agent 5-15 parts, a pH regulator 15-30 parts, and water 30-40 parts.

[0022] The following is a further optimization or / and improvement of the fourth technical scheme of the above application:

[0023] The reducing agent is one of hydroxylamine hydrochloride, hydroxylamine sulfate, diethyl hydroxylamine hydrochloride, hydrazine hydrochloride, hydrazine sulfate, hydrazine acetate, ammonium sulfide hydrochloride, and ammonium sulfite nitrate.

[0024] The pH regulator is one or more of hydrochloric acid, acetic acid, citric acid, and acrylic acid.

[0025] The iron ion stabilizer is prepared by the following steps:

[0026] The required amount of the complexing agent, the reducing agent, and the pH regulator are added to water, mixed and stirred uniformly to obtain the iron ion stabilizer.

[0027] The fifth technical scheme of the present application is realized by the following measures: a preparation method of the iron ion stabilizer of the fourth technical scheme, including the following steps:

[0028] The required amount of the complexing agent, the reducing agent, and the pH regulator are added to water, mixed and stirred uniformly to obtain the iron ion stabilizer.

[0029] The iron ion stabilizer of the present application is composed of a complexing agent, a reducing agent, and a pH regulator, which synergistically improve the iron stabilizing performance and temperature resistance. DETAILED DESCRIPTION

[0030] The present application is not limited by the following examples, and the specific implementation can be determined according to the technical scheme of the present application and the actual situation. The various chemical reagents and chemical products mentioned in the present application are well-known and commonly used chemical reagents and chemical products in the prior art unless otherwise specified; the percentages in the present application are mass percentages unless otherwise specified; the solutions in the present application are aqueous solutions with water as the solvent unless otherwise specified, for example, a hydrochloric acid solution is an aqueous hydrochloric acid solution; the normal temperature and room temperature in the present application generally refer to a temperature of 15-25℃, which is generally defined as 25℃.

[0031] The present application is further described below in conjunction with examples:

[0032] Example 1: The complexing agent is prepared by the following method:

[0033] Step one, dissolve the organic amine in the reaction solvent, add the unsaturated ester, and reflux to obtain a first mixed solution;

[0034] Step two, add base to the first mixed solution, continue the reaction, and remove the reaction solvent to obtain the complexing agent.

[0035] Example 2: As an optimization of the above examples, the reaction solvent is anhydrous methanol or anhydrous ethanol.

[0036] Example 3: As an optimization of the above examples, the organic amine is one or more of ethylenediamine, propylenediamine, ethanolamine, diethanolamine, tris(hydroxymethyl)aminomethane, diethylenetriamine, triethylenetetramine, polyethylene polyamine, and polyethyleneimine.

[0037] Example 4: As an optimization of the above examples, the unsaturated ester is one or more of dimethyl maleate, diethyl maleate, dimethyl itaconate, diethyl itaconate, dimethyl citraconate, and diethyl citraconate.

[0038] Example 5: As an optimization of the above examples, the base is one or more of sodium hydroxide, potassium hydroxide, and sodium methoxide.

[0039] Example 6: As an optimization of the above examples, the molar ratio of the unsaturated ester to the active hydrogen in the organic amine is 1 to 1.2, and the molar ratio of the base to the unsaturated ester is 2:1. That is, assuming that 1 mole of the organic amine has n moles of active hydrogen, the amount of the unsaturated ester used is n to 1.2n moles.

[0040] Example 7: As an optimization of the above examples, in step one, the reflux reaction temperature is 60°C to 80°C, and the reaction time is 6h to 24h.

[0041] Example 8: As an optimization of the above examples, in step two, the reaction temperature is 60°C to 80°C, and the reaction time is 2h to 6h.

[0042] Example 9: Application of the complexing agent in an acidizing and fracturing aid.

[0043] Example 10: The iron ion stabilizer, the raw materials include, by mass fraction: 10 parts of the complexing agent, 5 to 15 parts of the reducing agent, 15 to 30 parts of the pH adjuster, and 30 to 40 parts of water.

[0044] Example 11: As an optimization of the above example 10, the reducing agent is one of hydroxylamine hydrochloride, hydroxylamine sulfate, diethyl hydroxylamine hydrochloride, hydrazine hydrochloride, hydrazine sulfate, hydrazine acetate, ammonium sulfite hydrochloride, and ammonium nitrate sulfate.

[0045] Example 12: As an optimization of the above example 10, the pH adjuster is one or more of hydrochloric acid, acetic acid, citric acid, and acrylic acid.

[0046] Example 13: As an optimization of the above example 10, the iron ion stabilizer is prepared by the following steps:

[0047] The required amount of complexing agent, reducing agent and pH adjusting agent was added to water, mixed and stirred uniformly to obtain the iron ion stabilizer.

[0048] Example 14:

[0049] (1) Preparation of complexing agent:

[0050] 0.1 mol of diethanolamine was dissolved in 100 mL of dry methanol, 0.11 mol of dimethyl maleate was slowly added dropwise, and the reaction was refluxed at 70°C for 24 h. Then, 0.22 mol of sodium methoxide was added, and the reaction was continued for 2 h. Methanol was recovered by rotary evaporation to obtain the complexing agent N,N-bis(2-hydroxyethyl) aspartic acid sodium, denoted as L1.

[0051] The preparation reaction process of the complexing agent in this example is as follows:

[0052]

[0053] (2) Preparation of iron ion stabilizer:

[0054] 10.0 g of complexing agent L1, 10.0 g of citric acid, 10.0 g of acetic acid, 5.0 g of diethyl hydroxylamine hydrochloride and 0.5 mL of concentrated HCl were sequentially added to 32.0 g of tap water, mixed and stirred uniformly to obtain the iron ion stabilizer, denoted as S1.

[0055] Example 15:

[0056] (1) Preparation of complexing agent:

[0057] 0.1 mol of propylene diamine (PDA) was dissolved in 100 mL of dry methanol, 0.44 mol of dimethyl maleate was slowly added dropwise, and the reaction was refluxed at 70°C for 12 h. Then, 0.88 mol of sodium hydroxide was added, and the reaction was continued for 2 h. Methanol was recovered by rotary evaporation to obtain the complexing agent sodium propylene diamine tetra succinate, denoted as L2.

[0058]

[0059] (2) Preparation of iron ion stabilizer:

[0060] 10.0 g of complexing agent, 10.0 g of citric acid, 10.0 g of acetic acid, 5.0 g of hydroxylamine hydrochloride and 1 mL of concentrated HCl were sequentially added to 31.5 g of tap water, mixed and stirred uniformly to obtain the iron ion stabilizer, denoted as S2.

[0061] Example 16:

[0062] (1) Preparation of complexing agent:

[0063] The 0.1 mol of trishydroxymethyl aminomethane was dissolved in 100 mL dry methanol, 0.21 mol of dimethyl itaconate was added dropwise slowly, and the reaction was carried out at 70°C for 8 h. Then 0.42 mol of sodium hydroxide was added, and the reaction was continued for 2 h. Methanol was recovered by rotary evaporation to obtain the complexing agent N-tris(hydroxymethyl)methyl-N,N-bis(methyl succinate sodium), denoted as L3.

[0064]

[0065] (2) Preparation of iron ion stabilizer:

[0066] To 30.0 g of tap water, 10.0 g of complexing agent L3, 5.0 g of citric acid, 10.0 g of acrylic acid, 5.0 g of diethyl hydroxylamine hydrochloride, 5.0 g of hydrazine hydrochloride, and 2.5 mL of concentrated HCl were added in sequence, and the mixture was stirred uniformly to obtain an iron ion stabilizer, denoted as S3.

[0067] Example 17:

[0068] (1) Preparation of complexing agent: same as Example 16.

[0069] (2) Preparation of iron ion stabilizer:

[0070] To 30.0 g of tap water, 10.0 g of complexing agent L3, 10.0 g of citric acid, 5.0 g of acrylic acid, 5.0 g of diethyl hydroxylamine hydrochloride, 5.0 g of ammonium sulfite hydrochloride, and 2.5 mL of concentrated HCl were added in sequence, and the mixture was stirred uniformly to obtain an iron ion stabilizer, denoted as S4.

[0071] Comparative Example 1:

[0072] (1) Preparation of complexing agent: same as Example 14.

[0073] (2) Preparation of iron ion stabilizer:

[0074] To 42.0 g of tap water, 10.0 g of complexing agent L1, 10.0 g of acetic acid, 5.0 g of diethyl hydroxylamine hydrochloride, and 0.5 mL of concentrated HCl were added in sequence, and the mixture was stirred uniformly to obtain an iron ion stabilizer, denoted as D1.

[0075] Comparative Example 2:

[0076] (1) Preparation of complexing agent:

[0077] Preparation of complexing agent: same as Example 14.

[0078] (2) Preparation of iron ion stabilizer:

[0079] To 37.0g tap water, 10.0g of complexing agent L1, 10.0g of citric acid, 10.0g of acetic acid and 0.5mL of concentrated HCl were added successively, mixed and stirred uniformly to obtain an iron ion stabilizer, denoted as D2.

[0080] The stability of iron ions (Fe 3+ ) and temperature resistance of the iron ion stabilizers S1 to S4 prepared in Examples 14 to 17 and the iron ion stabilizers D1 and D2 of the comparative examples were evaluated according to the performance evaluation method for iron ion stabilizers for acidification SY / T 6571-2012, the test concentration of the iron ion stabilizer was 1%, and the evaluation temperatures were 25℃, 120℃ and 200℃ respectively, and the evaluation results are shown in Table 1.

[0081] Table 1

[0082] .

[0083] From the above Table 1, it can be seen that the iron ion stabilizer of the present application has good stability of iron ions and temperature resistance, and meets the performance index requirements of the iron ion stabilizer for acidification, and can be used for high-temperature reservoir acidification reconstruction.

[0084] The present application provides a kind of complexing agent and a kind of iron ion stabilizer, the iron ion stabilizer is composed of complexing agent, reducing agent and pH regulator, by the synergistic effect of three, greatly improve the stability of iron performance and temperature resistance.Simultaneously the complexing agent and iron ion stabilizer of the present application preparation process is simple, easy to control and realize, applicable to industrial large-scale production.

[0085] The above technical features respectively constitute the embodiments of the present application, which have 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. Use of a complexing agent in an aid for acidizing fracturing, characterized in that The complexing agent is prepared by the following steps: Step one, the organic amine is dissolved in the reaction solvent, the unsaturated ester is added, and the reaction is carried out under reflux to obtain a first mixed solution; Step two, the base is added to the first mixed solution, and the reaction is continued, and after removing the reaction solvent, the complexing agent is obtained; The organic amine is trimethylol aminomethylane; The unsaturated ester is dimethyl itaconate; The base is one or more of sodium hydroxide, potassium hydroxide and sodium methoxide.

2. Use of the complexing agent according to claim 1 in an aid for acidizing fracturing, characterized in that The reaction solvent is anhydrous methanol or anhydrous ethanol.

3. Use of the complexing agent according to claim 1 in an aid for acidizing fracturing, characterized in that The molar ratio of the unsaturated ester to the active hydrogen in the organic amine is 1 to 1.2, and the molar ratio of the base to the unsaturated ester is 2:

1.

4. Use of a complexing agent according to any one of claims 1 to 3 in an aid for acidizing fracturing, characterized in that In step one, the reflux reaction temperature is 60-80℃, and the reaction time is 6-24h.

5. Use of the complexing agent according to claim 4 in an aid for acidizing fracturing, characterized in that In step two, the reaction temperature is 60-80℃, and the reaction time is 2-6h.

6. An iron ion stabilizer using the complexing agent of claim 1 as a raw material, characterized by The raw materials include, by mass fraction: complexing agent 10 parts, reducing agent 5-15 parts, pH adjuster 15-30 parts, and water 30-40 parts; The reducing agent is one of hydroxylamine hydrochloride, hydroxylamine sulfate, diethyl hydroxylamine hydrochloride, hydrazine hydrochloride, hydrazine sulfate, hydrazine acetate, ammonium hydrochloride, and ammonium nitrate.

7. The ferric ion stabilizing agent according to claim 6, characterized by The pH adjuster is one or more of hydrochloric acid, acetic acid, citric acid, and acrylic acid.

8. A method for producing the ferric ion stabilizer according to claim 6 or 7, characterized by The following steps are included: The required amount of complexing agent, reducing agent and pH adjuster is added to water, and mixed and stirred uniformly to obtain an iron ion stabilizer.

Images