Superstrong permeable single-phase retarded acid capable of being regulated and controlled in different stratums and preparation method of superstrong permeable single-phase retarded acid

Abstract

The invention provides super-strong permeable single-phase retarded acid capable of being regulated and controlled in different stratums and a preparation method thereof, and the retarded acid is prepared from the following raw materials in parts by weight: 35-55 parts of industrial-grade acid, 3-5 parts of a corrosion inhibitor, 0.6-1.2 parts of a novel retarder, 0.1-0.3 part of an iron ion stabilizer and 80-120 parts of water. The single-phase retarded acid provided by the invention has super-strong high temperature resistance, relatively low corrosion rate and acid solubility, and can enable an acid solution to enter a deep layer of a reservoir, so that the acidification effect is enhanced, and the yield of an oil field is further improved.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, specifically relating to a super-permeable single-phase slow-release acid that can be controlled in different formations and its preparation method. Background Technology

[0002] In the process of oilfield development, acidizing is an important production enhancement measure, which is beneficial to increasing the production of oil wells and the injection capacity of injection wells.

[0003] Currently, the adaptability and effectiveness of traditional slow-response acid systems on the market are limited under different formation conditions, making it difficult to meet the needs of modern oilfields for efficient, precise, and environmentally friendly acidizing. On the one hand, in acidizing operations, traditional acids have poor retardation performance; conventional acids exhibit excessively fast reaction rates, failing to fully realize their potential for transformation. Alternatively, excessive amounts of retarders are added to achieve a slowing effect, impacting subsequent reservoir production performance. On the other hand, the single-phase stability and adaptability of existing acids need improvement. In complex underground environments and under different formation conditions, acids are prone to phase separation and precipitation, affecting their homogeneity and reaction consistency. They lack sufficient adaptability to situations with dynamic changes in formation conditions or the superposition of multiple complex factors.

[0004] Chinese patent CN 110564398 A discloses a slow-release acid system, the components of which include alkyltrimethylammonium chloride and water-soluble calcium salt, corrosion inhibitor Mannich base and iron ion stabilizer, wherein the alkyl group is a long-chain alkyl group containing 8-22 carbon atoms; the slow-release acid system of this invention has low viscosity and can penetrate small-scale cracks to perform non-uniform etching on their walls; however, when the temperature exceeds 150 ℃, the corrosion inhibition of Mannich base will deteriorate, therefore, this slow-release system is not suitable for high-temperature reservoirs.

[0005] Therefore, there is an urgent need for a super-permeable single-phase slow-release acid that can be controlled in different formations and has excellent high-temperature resistance and low corrosion resistance. Summary of the Invention

[0006] To address the existing technical problems, the present invention aims to provide a highly permeable single-phase slow-release acid that can be controlled across different formations, and its preparation method. The single-phase slow-release acid provided by this invention possesses superior high-temperature resistance, low corrosion rate, and low acid solubility, enabling the acid to penetrate deep into the reservoir, enhancing the acidizing effect, and thereby increasing oilfield production.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The present invention provides a super-permeable single-phase slow-release acid that can be controlled in different formations. By weight, the slow-release acid contains the following raw materials: 35-55 parts of industrial-grade basic acid, 3-5 parts of corrosion inhibitor, 0.6-1.2 parts of novel slow-release agent, 0.1-0.3 parts of iron ion stabilizer, and 80-120 parts of water.

[0008] The reaction mechanism and function of this invention are as follows: 1. The novel retarder of the present invention is composed of acrylamide, β-(acryloyloxy)propionic acid, allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, and N-vinylimidazolium, and has good acid solubility, high temperature resistance and low corrosion.

[0009] On the one hand, the amide and carboxylic acid groups in the molecular structure of the novel retarder have good solubility in acid, ensuring that the retarder molecules can dissolve rapidly in acid. On the other hand, the introduction of allyl polyethylene glycol can reduce the viscosity of the system, making it easier to penetrate the formation, increase the acidizing range, reduce formation damage, and endow the retarder with good water solubility and lubricity.

[0010] On the other hand, the carboxylic acid groups in β-(acryloyloxy)propionic acid can exhibit stronger adsorption with active sites on the rock surface, forming a denser and more stable isolation film. This isolation film can more effectively prevent hydrogen ions in the acid solution from directly contacting the rock, further slowing down the acid-rock reaction rate, and also preventing excessive corrosion and damage to the rock by the acid solution. Simultaneously, the introduction of allyl polyethylene glycol as a hydrophobic monomer allows its long hydrophobic chains to arrange themselves in a regular and oriented manner, forming a hydrophobic film that hinders H+ ion exchange. + The propagation of [something] reduces the acid-rock reaction rate.

[0011] Furthermore, the imidazole group in the novel retarder is effective against H. + It has a certain trapping ability and can form a structure similar to hydrochloride with acid. The trapped H+ + It can be gradually released at high temperatures, and the benzene ring structure on acryloyloxyethyl dimethyl benzyl ammonium chloride and the imidazole structure on N-vinylimidazolium further enhance the resistance of H in the acid solution used for high-temperature deep acidification. + Become more stable, thereby reducing H + The consumption rate reaches H + The slow release effect allows for deep acidification at a distance.

[0012] 2. The corrosion inhibitor selected in this invention is composed of a mixture of 1-benzylquinoline chloride, 1,4-butynediol and hexamethylenetetramine in a certain mass ratio. The combination of the three can remain stable under high temperature conditions, ensuring that the corrosion inhibitor can still play an effective role in oilfield acidizing operations, maintain the isolation effect between acid and metal, and thus reduce the corrosion rate.

[0013] 1-Benzylquinoline chloride can effectively adsorb onto the metal surface, forming a protective film that prevents acid from contacting the metal and reduces the corrosion rate. The addition of 1,4-butynediol improves the dispersibility of the corrosion inhibitor in the acid, ensuring its uniform distribution and enhancing the stability of the protective film. Meanwhile, hexamethylenetetramine contains multiple amino functional groups, which decompose under acidic conditions to produce corrosion-inhibiting substances, synergistically enhancing the corrosion inhibition effect under high-temperature operation with 1-benzylquinoline chloride.

[0014] In some embodiments, the preparation steps of the novel retarder are as follows: S1. Mix acrylamide, β-(acryloyloxy)propionic acid and distilled water, stir, and obtain monomer solution 1; S2. Mix allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, N-vinylimidazol, distilled water, and anhydrous ethanol, and stir to obtain monomer solution 2; S3. Transfer monomer solution 1 obtained in step S1 to a reaction vessel, adjust the pH value to 6.5-7.0, heat to 60-70℃, add initiator while maintaining a stirring rate of 100-150r / min, then add monomer solution 2 obtained in step S2 dropwise, continuously pass in inert gas, keep the reaction at the temperature for 5-7h, rotary evaporate, add anhydrous acetic acid, filter to obtain precipitate, wash the precipitate with anhydrous diethyl ether, filter, and vacuum dry to obtain a novel retarder.

[0015] In some embodiments, the industrial-grade amino acid is 37 wt% industrial-grade hydrochloric acid.

[0016] In some embodiments, the mass ratio of acrylamide to β-(acryloyloxy)propionic acid in step S1 is 1:(0.4-0.8).

[0017] In some embodiments, the molecular weight of the allyl polyethylene glycol in step S2 is 1000-2500.

[0018] In some embodiments, the mass ratio of allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, and N-vinylimidazole in step S2 is 1:(0.7-1.2):(0.2-0.6).

[0019] In some embodiments, the initiator in step S3 is 0.3-0.5% of the total mass of the monomers, which include acrylamide, β-(acryloyloxy)propionic acid, allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, and N-vinylimidazole.

[0020] In some embodiments, the corrosion inhibitor is a combination of 1-benzylquinoline chloride, 1,4-butynediol, and hexamethylenetetramine.

[0021] In some embodiments, the mass ratio of the 1-benzylquinoline chloride, 1,4-butynediol, and hexamethylenetetramine is 1:(3.5-5):(1.1-1.4).

[0022] In some embodiments, the iron ion stabilizer is any one or more of o-phenanthroline, citric acid, and isoascorbic acid.

[0023] Another aspect of the present invention provides a method for preparing a highly permeable single-phase slow-release acid that can be controlled in different formations, comprising the following steps: Industrial-grade basic acid and water are mixed, a new type of retarder is added, the mixture is stirred, and left to stand for 2-4 hours. Then, a corrosion inhibitor and an iron ion stabilizer are added in sequence, and the mixture is stirred to obtain a retarded acid.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. The single-phase slow-release acid provided by this invention has excellent high-temperature resistance, low corrosion rate and acid solubility, which enables the acid to penetrate deep into the reservoir, enhances the acidification effect, and thus improves oilfield production.

[0025] 2. The novel retarder of this invention is composed of acrylamide, β-(acryloyloxy)propionic acid, allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, and N-vinylimidazole, and possesses good acid solubility, high temperature resistance, and low corrosivity. The amide groups, carboxylic acid groups, and allyl polyethylene glycol contained in the retarder facilitate dissolution and improve permeability; while the carboxylic acid groups, imidazole groups, and hydrophobic long chains form a dense isolating film that hinders acid-rock reactions. Furthermore, the imidazole groups and benzene ring structure possess high temperature resistance, preventing the H+ in the acid solution from reacting. + It remains stable, thus reducing H. + The consumption rate reaches H + The slow-release effect is suitable for acidification of deep reservoirs in remote areas that require high-temperature resistance.

[0026] 3. The corrosion inhibitor of the present invention is composed of 1-benzylquinoline chloride, 1,4-butynediol and hexamethylenetetramine mixed in a certain mass ratio. It can play a stable role in high temperature environment, and the three substances synergistically enhance the corrosion inhibition effect. Detailed Implementation

[0027] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0028] Each single-phase slow acid was prepared according to the proportions and preparation methods of the raw materials specified in the following examples and comparative examples.

[0029] To facilitate implementation of this invention by those skilled in the art, the manufacturers of some raw materials for the embodiments and comparative examples are described below: Allyl polyethylene glycol: purchased from Haian Petrochemical Plant, Jiangsu Province, models APEG-800 and APEG-2000; Unless otherwise specified, all other raw materials can be purchased from the market.

[0030] Preparation Example 1 The preparation method of the novel retarder A includes the following steps: S1. Mix 200g acrylamide, 120g β-(acryloyloxy)propionic acid and 650g distilled water, stir well to obtain monomer solution 1; S2. Mix 80g allyl polyethylene glycol APEG-2000, 76g acryloyloxyethyl dimethyl benzyl ammonium chloride, 32g N-vinylimidazol, 250mL distilled water, and 150mL anhydrous ethanol, and stir until homogeneous to obtain monomer solution 2. S3. Transfer monomer solution 1 obtained in step S1 to a reaction vessel, adjust the pH value to 6.8, heat to 65°C, add 2g of azobisisobutyramidine hydrochloride while maintaining a stirring rate of 120r / min, then add monomer solution 2 obtained in step S2 dropwise, continuously purge with nitrogen gas, and keep the reaction at this temperature for 6h. Remove the solvent by rotary evaporation, add anhydrous acetic acid, shake for 10min, filter to obtain the precipitate, wash the precipitate with anhydrous diethyl ether, filter, and vacuum dry at 80°C to constant weight to obtain the novel retarder A.

[0031] Preparation Example 2 The preparation method of the novel retarder B is the same as that in Preparation Example 1, except that the amount of β-(acryloyloxy)propionic acid added is 60g.

[0032] Preparation Example 3 The preparation method of the novel retarder C is the same as that in Preparation Example 1, except that the amount of acryloyloxyethyl dimethyl benzyl ammonium chloride added is 48g.

[0033] Preparation Example 4 The preparation method of the novel retarder D is the same as that in Preparation Example 1, except that the amount of N-vinylimidazole added is 12g.

[0034] Preparation Example 5 The preparation method of the novel retarder E is the same as that in Preparation Example 1, except that the allyl polyethylene glycol is APEG-800.

[0035] Example 1 A highly permeable single-phase slow-release acid that can be controlled in different formations, comprising, by weight, the following raw materials: 40 parts of 37wt% industrial-grade hydrochloric acid, 4 parts of corrosion inhibitor, 0.9 parts of novel slow-release agent A, 0.2 parts of isoascorbic acid, and 100 parts of water, wherein the corrosion inhibitor is a composition of 1-benzylquinoline chloride, 1,4-butynediol, and hexamethylenetetramine in a mass ratio of 1:4.25:1.25.

[0036] The method for preparing the slow-release acid in this embodiment includes the following steps: Mix 37wt% industrial-grade hydrochloric acid and water, add novel retarder A, stir well, let stand for 3 hours, then add corrosion inhibitor and isoascorbic acid in sequence, stir well to obtain retarded acid.

[0037] Example 2 A highly permeable single-phase slow-release acid that can be controlled in different formations, comprising, by weight, the following raw materials: 35 parts of 37wt% industrial-grade hydrochloric acid, 3 parts of corrosion inhibitor, 0.6 parts of novel slow-release agent A, 0.1 parts of citric acid, and 80 parts of water, wherein the corrosion inhibitor is a composition of 1-benzylquinoline chloride, 1,4-butynediol, and hexamethylenetetramine in a mass ratio of 1:3.5:1.1.

[0038] The method for preparing the slow-release acid in this embodiment includes the following steps: Mix 37wt% industrial-grade hydrochloric acid and water, add novel retarder A, stir well, let stand for 2 hours, then add corrosion inhibitor and citric acid in sequence, stir well to obtain retarded acid.

[0039] Example 3 A highly permeable single-phase slow-release acid that can be controlled in different formations, comprising, by weight, the following raw materials: 55 parts of 37wt% industrial-grade hydrochloric acid, 5 parts of corrosion inhibitor, 1.2 parts of novel slow-release agent A, 0.3 parts of isoascorbic acid, and 120 parts of water, wherein the corrosion inhibitor is a composition of 1-benzylquinoline chloride, 1,4-butynediol, and hexamethylenetetramine in a mass ratio of 1:5:1.4.

[0040] The method for preparing the slow-release acid in this embodiment includes the following steps: Mix 37wt% industrial-grade hydrochloric acid and water, add novel retarder A, stir well, let stand for 4 hours, then add corrosion inhibitor and isoascorbic acid in sequence, stir well to obtain retarded acid.

[0041] Example 4 A highly permeable single-phase slow-release acid that can be controlled in different formations and its preparation method are described. The specific implementation method is the same as in Example 1, except that an equal amount of novel slow-release agent B is used instead of novel slow-release agent A.

[0042] Example 5 A highly permeable single-phase slow-release acid that can be controlled in different formations and its preparation method are described. The specific implementation method is the same as in Example 1, except that an equal amount of novel slow-release agent C is used instead of novel slow-release agent A.

[0043] Example 6 A highly permeable single-phase slow-release acid that can be controlled in different formations and its preparation method are described. The specific implementation method is the same as in Example 1, except that an equal amount of novel slow-release agent D is used instead of novel slow-release agent A.

[0044] Example 7 A highly permeable single-phase slow-release acid that can be controlled in different formations and its preparation method are described. The specific implementation method is the same as in Example 1, except that an equal amount of novel slow-release agent E is used instead of novel slow-release agent A.

[0045] Example 8 A highly permeable single-phase slow-resolved acid that can be controlled in different formations and its preparation method are described. The specific implementation method is the same as in Example 1, except that the corrosion inhibitor is a composition of 1-benzylquinoline chloride, 1,4-butynediol and hexamethylenetetramine in a mass ratio of 1:4.25:0.9.

[0046] Example 9 A highly permeable single-phase slow-resolved acid that can be controlled in different formations and its preparation method are described. The specific implementation method is the same as in Example 1, except that the corrosion inhibitor is a composition of 1-benzylquinoline chloride and 1,4-butynediol in a mass ratio of 1:4.25.

[0047] Comparative Example 1 A highly permeable single-phase slow-release acid that can be controlled in different formations and its preparation method are described. The specific implementation method is the same as in Example 1, except that an equal amount of commercially available dodecyltributylphosphine bromide is used to replace the novel slow-release acid.

[0048] Effect evaluation: I. The single-phase slow-rate acids prepared in Examples 1-7 and Comparative Example 1 were subjected to slow-rate tests. The specific results are shown in Table 1.

[0049] Select a square marble block with sides of 5cm, add it to a slow-release acid for reaction, and follow the steps below: 1) Clean the marble block with deionized water, place it in a drying oven and dry it at 100℃ until constant weight, record this as m1. 2) Take 300 mL of slow-release acid for the experiment, and place it in a constant-temperature pot. After the temperature reaches 90℃, add marble blocks to react and start timing. After reacting for 5 minutes, remove the remaining marble blocks, rinse them with deionized water, label them, and dry them in an oven at 100℃. After constant weight, remove them, weigh them, and record the weight as m. 2； 3) The slow rate is calculated using the following formula, where V represents the acid-rock reaction rate in g / min; Δt is the time of the acid-rock reaction in min; γ represents the slow rate of the acid solution; V0 is the reaction rate of the blank control group, i.e., the reaction rate of 16.65% hydrochloric acid aqueous solution with marble block in g / min; V1 is the reaction rate of the slow acid solution with marble block in g / min. V = (m1-m2) / Δt γ = (V0-V1) / V0× 100%.

[0050] 2. Mix the prepared slow-release acid with water at a ratio of 1:3, place it in a temperature- and pressure-resistant container, age it at a certain temperature for 4 hours, remove it, cool it to room temperature, filter the acid solution, and weigh the filter residue. If the amount of filter residue is less than 500 mg / L, it is considered qualified. The aging temperature is used to characterize the temperature resistance performance.

[0051] Table 1 As can be seen from the results in Table 1, Examples 1-3 of the present invention have low corrosion rates and excellent high-temperature resistance.

[0052] Compared to Example 1, in the preparation of the novel retarder, Example 4 changed the mass ratio of acrylamide and β-(acryloyloxy)propionic acid, resulting in a weakened adsorption effect on the active sites on the rock surface; Examples 5-6 changed the mass ratio of allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, and N-vinyl imidazole, reducing the number of benzene rings and imidazole groups, thus decreasing the high-temperature resistance, and the imidazole groups had a reduced effect on H + The stability of the membrane is significantly affected; Example 7 altered the molecular weight of allyl polyethylene glycol, shortening the hydrophobic segments; all of these factors contribute to insufficient density of the membrane, thus affecting the retarding rate. In Comparative Example 1, replacing novel retarder A with dodecyltributylphosphine bromide not only affected the retarding rate but also decreased high-temperature resistance.

[0053] 3. The corrosion rate of the single-phase slow-resistance acids prepared in Examples 1-3 and 8-9 above was tested. The reference standard was SY / T 5405-2019 Test method and evaluation index for performance of corrosion inhibitors for acidification. The experimental conditions were: the test piece material was N80 steel, the test pressure was 16 MPa, the stirring speed was 60 r / min, the acidification time was 5 h, and the acidification temperature was 180℃. The corresponding corrosion rate was tested, and the specific results are shown in Table 2.

[0054] Table 2 As can be seen from the results in Table 1, Examples 1-3 of the present invention exhibit a low corrosion rate at high temperatures.

[0055] Compared to Example 1, Examples 8-9 changed the type and ratio of corrosion inhibitors. Example 8 changed the mass ratio of 1-benzylquinoline chloride, 1,4-butynediol and hexamethylenetetramine, which reduced the corrosion-inhibiting substances produced by the decomposition of hexamethylenetetramine. Example 9 only added 1-benzylquinoline chloride and 1,4-butynediol, which resulted in the loss of synergistic effect and thus affected the corrosion rate.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present application in any way. Although the present application discloses the preferred embodiment as described above, it is not intended to limit the present application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of the present application using the disclosed technical content are equivalent to equivalent implementation cases. Any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the scope of the technical solution of the present invention are still within the scope of the technical solution.

Claims

1. A highly permeable single-phase slow-release acid that can be controlled in different formations, characterized in that, By weight, the retarding acid comprises the following raw materials: 35-55 parts of industrial grade basic acid, 3-5 parts of corrosion inhibitor, 0.6-1.2 parts of novel retarding agent, 0.1-0.3 parts of iron ion stabilizer, and 80-120 parts of water.

2. The ultra-permeable single-phase slow-release acid that can be controlled in different formations according to claim 1, characterized in that, The preparation steps of the novel retarder are as follows: S1. Mix acrylamide, β-(acryloyloxy)propionic acid and distilled water, stir, and obtain monomer solution 1; S2. Mix allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, N-vinylimidazol, distilled water, and anhydrous ethanol, and stir to obtain monomer solution 2; S3. Transfer monomer solution 1 obtained in step S1 to a reaction vessel, adjust the pH value to 6.5-7.0, heat to 60-70℃, add initiator while maintaining a stirring rate of 100-150r / min, then add monomer solution 2 obtained in step S2 dropwise, continuously pass in inert gas, keep the reaction at the temperature for 5-7h, rotary evaporate, add anhydrous acetic acid, filter to obtain precipitate, wash the precipitate with anhydrous diethyl ether, filter, and vacuum dry to obtain a novel retarder.

3. The ultra-permeable single-phase slow-release acid that can be controlled in different formations according to claim 2, characterized in that, The mass ratio of acrylamide to β-(acryloyloxy)propionic acid in step S1 is 1:(0.4-0.8).

4. The ultra-permeable single-phase slow-release acid that can be controlled in different formations according to claim 2, characterized in that, The molecular weight of the allyl polyethylene glycol mentioned in step S2 is 1000-2500.

5. The ultra-permeable single-phase slow-release acid that can be controlled in different formations according to claim 2, characterized in that, In step S2, the mass ratio of allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, and N-vinylimidazolium is 1:(0.7-1.2):(0.2-0.6).

6. The ultra-permeable single-phase slow-release acid that can be controlled in different formations according to claim 2, characterized in that, The initiator in step S3 has a mass of 0.3-0.5% of the total mass of the monomers, which include acrylamide, β-(acryloyloxy)propionic acid, allyl polyethylene glycol, acryloyloxyethyl dimethyl benzyl ammonium chloride, and N-vinylimidazolium.

7. The ultra-permeable single-phase slow-release acid that can be controlled in different formations according to claim 1, characterized in that, The corrosion inhibitor is a combination of 1-benzylquinoline chloride, 1,4-butynediol and hexamethylenetetramine.

8. The ultra-permeable single-phase slow-release acid that can be controlled in different formations according to claim 7, characterized in that, The mass ratio of the 1-benzylquinoline chloride, 1,4-butynediol and hexamethylenetetramine is 1:(3.5-5):(1.1-1.4).

9. The ultra-permeable single-phase slow-release acid that can be controlled in different formations according to claim 1, characterized in that, The iron ion stabilizer is any one or more of o-phenanthroline, citric acid, and isoascorbic acid.

10. A method for preparing a highly permeable single-phase slow-release acid capable of being controlled in different formations, as described in any one of claims 1-9, characterized in that, Includes the following steps: Industrial-grade basic acid and water are mixed, a new type of retarder is added, the mixture is stirred, and left to stand for 2-4 hours. Then, a corrosion inhibitor and an iron ion stabilizer are added in sequence, and the mixture is stirred to obtain a retarded acid.

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