Use of compounds as emulsifiers, emulsifier compositions, emulsified acid systems and emulsified acids and uses, methods of making emulsified acids

Abstract

The application relates to the field of emulsifiers, and discloses application of a compound as an emulsifier, an emulsifier composition and application, an emulsified acid system, emulsified acid and a preparation method and application thereof. The compound has a structure as shown in formula (1): wherein A + , B + are each independently selected from metal cations; R1 and R2 are each independently selected from one of H and C6-C16 alkyl; n is an integer of 1-9; m is an integer of 1-9; and p is an integer of 1-9. The emulsifier provided by the application can ensure that an emulsified acid system has excellent high-temperature stability when being used in the emulsified acid system by reasonably designing the length of a hydrophobic chain and the length of a linking group, and simultaneously introducing sulfonic acid ions which have strong hydration ability, acid resistance and high-temperature resistance.

Description

Technical Field

[0001] This invention relates to the field of emulsifiers, specifically to the application of a compound as an emulsifier, emulsifier compositions, emulsifying acid systems and emulsifying acids and their applications, and methods for preparing emulsifying acids. Background Technology

[0002] With the increasingly widespread application of emulsified acids, high-temperature stability is currently the most pressing issue to be addressed. As an emulsion system, the stability of emulsified acids is directly related to the emulsifier. The emulsifier directly determines the strength of the oil-water interfacial film and the contact area of ​​the lipophilic groups during emulsion formation. A stronger interfacial film results in a lower degree of uneven distribution of the emulsifier on the film, and a lower tendency for demulsification. A larger and tighter contact area of ​​the lipophilic groups leads to greater anti-polymerization properties and stability of the emulsion. Therefore, ensuring the high-temperature stability of emulsified acids places high demands on the emulsifiers used in them. Summary of the Invention

[0003] The purpose of this invention is to overcome the problem of instability of emulsified acids under high-temperature conditions in existing technologies, and to provide an application of a compound as an emulsifier, an emulsifier composition, an emulsified acid system, an emulsified acid and its application, and a method for preparing an emulsified acid. This compound, as an emulsifier, ensures the high-temperature stability of the emulsified acid system by rationally designing the hydrophobic chain length and linker length, and by introducing sulfonate ions with strong hydration ability, acid resistance, and high-temperature resistance.

[0004] To achieve the above objectives, a first aspect of the present invention provides the application of the compound represented by formula (1) as an emulsifier, characterized in that:

[0005]

[0006] Among them, A + B + Each is independently selected from metal cations;

[0007] R1 and R2 are each independently selected from H or C6-C16 alkyl groups; n is an integer from 1 to 9; m is an integer from 1 to 9; p is an integer from 1 to 9. Among them, -(CH2)SO3A and -(CH2)SO3B are hydrophilic groups; -NR1- and -NR2- are lipophilic groups; -(CH2) m - is a linking group.

[0008] A second aspect of the present invention provides an emulsifier composition comprising the above-mentioned emulsifier and a W / O type emulsifier.

[0009] A third aspect of the present invention provides the application of the above-described emulsifier composition in emulsified acid systems.

[0010] A fourth aspect of the present invention provides an emulsified acid system comprising an acid, an oil, and the above-described emulsifier composition.

[0011] The fifth aspect of the present invention provides an emulsified acid, which is prepared according to the above-described emulsified acid system.

[0012] The sixth aspect of the present invention provides a method for preparing an emulsified acid, the method comprising: dispersing the components in the above-mentioned emulsified acid system evenly to obtain the emulsified acid.

[0013] The seventh aspect of the present invention provides an application of the above-mentioned emulsified acid in oilfield acidification.

[0014] Through the above technical solutions, the application of the compound as an emulsifier, the emulsifier composition, the emulsifying acid system, the emulsifying acid and its application, and the preparation method of the emulsifying acid provided by the present invention achieve the following beneficial effects:

[0015] This invention provides the application of the compound shown in formula (1) as an emulsifier. By rationally designing the length of the hydrophobic chain and the length of the linker, and introducing sulfonate ions with strong hydration ability, acid resistance, and high temperature resistance, a highly efficient emulsifier is obtained. This emulsifier is a cationic emulsifier under acidic conditions. Among them, the interaction between the hydrophilic end groups is adjusted: when the length of the linker is different, the interaction distance between the hydrophilic end groups is different, resulting in different packing densities, which strongly affects the adsorption and aggregation morphology and strength of the emulsifier at the interface. Within a certain range, the emulsifier is more tightly arranged at the interface and has better surface activity as the length of the linker increases, thus resulting in better high-temperature stability. The sulfonate group of the hydrophilic group has good acid resistance. Under acidic conditions, the emulsifier is more tightly arranged at the oil-water interface through intermolecular hydrogen bonding. Within a certain range, increasing the number of carbon atoms of R1 and R2 can effectively enhance the intermolecular cohesion and improve the viscoelasticity of the adsorption film and the stability of the emulsion. Beyond a certain range, the number of carbon atoms of the hydrophobic group continues to increase, which will lead to a decrease in its solubility in the system.

[0016] This invention provides a high-performance emulsifier composition for high-temperature emulsified acids by combining an emulsifier with a specific structure provided by this invention with a W / O type emulsifier. This composition can be used for various oil phases such as light crude oil, diesel oil, and white oil. The W / O type emulsifier forms a wedge-shaped close-packed structure at the oil-water interface, forming a stable and dense interfacial film, which improves the stability of the emulsion system under acidic conditions. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The first aspect of the present invention provides the use of the compound represented by formula (1) as an emulsifier:

[0019]

[0020] Among them, A + B + Each R1 and R2 is independently selected from a metal cation; each R1 and R2 is independently selected from H or a C6-C16 alkyl group; n is an integer from 1 to 9; m is an integer from 1 to 9; p is an integer from 1 to 9. As a further explanation, when R1 and R2 are selected from C6-C16 alkyl groups, the present invention does not particularly limit whether the alkyl group is straight-chain or branched, but preferably a straight-chain alkane. Wherein, -(CH2)SO3A and -(CH2)SO3B are hydrophilic groups; -NR1- and -NR2- are lipophilic groups; -(CH2) m - is a linking group.

[0021] This invention, through the rational design of hydrophobic chain length and linker length, introduces sulfonate ions with strong hydration ability, acid resistance, and high temperature resistance to obtain a highly efficient emulsifier. This emulsifier is a cationic emulsifier under acidic conditions.

[0022] Furthermore, this invention regulates the interaction between hydrophilic end groups by adjusting the length of the linker. Different linker lengths result in different interaction distances between the hydrophilic end groups, leading to different packing densities and significantly affecting the adsorption, aggregation morphology, and strength of the emulsifier at the interface. Within a certain range, a longer linker length results in a more compact arrangement of the emulsifier at the interface, better surface activity, and thus better high-temperature stability. Additionally, the introduction of sulfonic acid groups with hydrophilic components provides better acid resistance. Under acidic conditions, intermolecular hydrogen bonding further enhances the compact arrangement of the emulsifier at the oil-water interface. Furthermore, within a certain range, increasing the carbon number of R1 and R2 effectively strengthens intermolecular cohesion, improving the viscoelasticity of the adsorption film and the stability of the emulsion. However, beyond a certain range, further increases in the carbon number of the hydrophobic groups lead to a decrease in their solubility within the system.

[0023] According to the present invention, in order to further improve the performance of the emulsifier, preferably, A + B + Each is independently selected from alkali metal cations (such as Na).+ K + Li + ), preferably Na + or K + Preferably, R1 and R2 are each independently a C8-C14 alkyl group, more preferably a C10-C12 alkyl group; preferably, n is an integer from 3 to 7, more preferably an integer from 3 to 5; preferably, m is an integer from 3 to 7, more preferably an integer from 3 to 5; preferably, p is an integer from 3 to 7, more preferably an integer from 3 to 5.

[0024] According to the present invention, A + B + They can be the same or different; R1 and R2 can be the same or different; n and p can be the same or different.

[0025] In one specific embodiment of the present invention, in the emulsifier shown in formula (1), A + B + All are Na + n, m, and p are all 3, and R1 and R2 are both C. 10 H 21 .

[0026] In another specific embodiment of the present invention, in the emulsifier shown in formula (1), A + B + All are Na + n, m, and p are all 3, and R1 and R2 are both C. 12 H 25 .

[0027] A second aspect of the present invention provides an emulsifier composition comprising the above-mentioned emulsifier and a W / O type emulsifier.

[0028] The emulsifier with the structure shown in formula (1) provided by the first aspect of the present invention has excellent acid resistance. When combined with a W / O type emulsifier with excellent interfacial stability, it forms an acid-resistant emulsifier that can withstand high temperatures up to 140°C. The W / O type emulsifier forms a wedge-shaped close-packed structure at the oil-water interface, forming a stable and dense interfacial film, thereby improving the stability of the emulsion system under acidic conditions.

[0029] According to the present invention, the W / O type emulsifier is selected from at least one of alkylphenol polyoxyethylene ether, polyoxyethylene dimerhydroxystearate, sorbitan oleate and polyoxyethylene oleyl alcohol ether; preferably, the W / O type emulsifier is selected from at least one of alkylphenol polyoxyethylene ether, polyoxyethylene dimerhydroxystearate and sorbitan oleate; more preferably, the W / O type emulsifier is selected from alkylphenol polyoxyethylene ether and / or polyoxyethylene-dimerichydroxystearate, such as polyoxyethylene (30) dimerhydroxystearate.

[0030] In this invention, the use of the above-mentioned specific type of W / O emulsifier has the following advantages: First, under acidic conditions, through intermolecular hydrogen bonding, the emulsifier with the structure shown in formula (1) is more tightly arranged at the oil-water interface, and has better acid resistance; Second, the adsorption membrane has high viscoelasticity and the emulsion has good stability.

[0031] According to the present invention, the mass ratio of the W / O type emulsifier and the emulsifier shown in formula (1) is 0.5-7:1.

[0032] In this invention, when the mass ratio of the emulsifier shown in formula (1) to the W / O type emulsifier meets the above range, as the total concentration of the emulsifier increases, the number of emulsifier molecules at the oil-acid interface increases, the film formed is more compact, and the system containing the emulsifier composition is more stable.

[0033] Taking into account the cost, the mass ratio of the W / O type emulsifier to the emulsifier shown in formula (1) is further 1-6:1, more preferably 2-5:1.

[0034] A third aspect of the present invention provides the application of the above-described emulsifier composition in emulsified acid systems.

[0035] A fourth aspect of the present invention provides an emulsified acid system comprising an acid, an oil, and any one of the above-described emulsifier compositions.

[0036] In this invention, the emulsified acid system containing the above-mentioned emulsifier composition has good high-temperature stability.

[0037] According to the present invention, in the emulsified acid system, based on the volume of oil, the amount of the emulsifier composition is 0.01-0.05 g / mL, and based on H... + The amount of acid used is 5-12 mmol / mL.

[0038] In this invention, the emulsified acid system having the above composition has better high-temperature stability.

[0039] According to the present invention, preferably, the amount of the emulsifier composition is 0.015-0.035 g / mL based on the volume of oil, and H... + The amount of acid used is 6-10 mmol / mL.

[0040] According to the present invention, the acid is selected from organic acids and / or inorganic acids; preferably, it is one of hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid; the oil is selected from C8-C33 oils, preferably one of diesel oil, white oil, and light crude oil. As a further explanation, the density of diesel oil can be between 0.83 and 0.855 g / mL; the kinematic viscosity (40°C) of white oil can be between 4 and 11 m³ / mL.2 The relative density of light crude oil is generally between 0.75 and 0.95 g / mL, with a few exceeding 0.95 g / mL or falling below 0.75 g / mL.

[0041] The fifth aspect of the present invention provides an emulsified acid, which is prepared from the above-described emulsified acid system.

[0042] The sixth aspect of the present invention provides a method for preparing an emulsified acid, the method comprising: dispersing the components in the above-mentioned emulsified acid system evenly to obtain the emulsified acid.

[0043] The present invention does not particularly limit the method of adding each component in the emulsified acid system, as long as the components can be evenly dispersed. For example, the following method can be used: dissolve the emulsifier composition in the oil, add the acid and disperse it evenly to obtain the emulsified acid.

[0044] This invention provides an exemplary method for preparing emulsified acids:

[0045] Step 1: Prepare hydrochloric acid solution;

[0046] Step 2: Measure the oil phase, add the emulsifier, and heat and stir in a water bath at 40-60℃ until completely dissolved;

[0047] Step 3: Place the oil phase, which has been cooled to room temperature, into a two-necked flask. Under high-speed stirring, add the acid phase dropwise into the oil phase. After all the acid phase has been added, stir for a period of time to obtain emulsified acid.

[0048] The seventh aspect of the present invention provides an application of the above-mentioned emulsified acid in oilfield acidification.

[0049] The present invention will be described in detail below through examples. In the following examples and comparative examples, the sources of raw materials, the equipment used, and the testing methods are as follows:

[0050] Experimental materials:

[0051] Hydrochloric acid, analytical grade, purchased from Tianjin Guangfu Fine Chemical Research Institute;

[0052] 0 # Diesel fuel, density 0.835 g / mL, purchased from Beijing Taihengrong Petrochemical Co., Ltd.

[0053] W / O type emulsifier, designated as emulsifier A, industrial grade, purchased from Shantou Xunnuo Chemical Technology Co., Ltd.;

[0054] The emulsifier shown in formula (1), denoted as emulsifier B, is prepared in the laboratory. In this emulsifier, A... + and B + All are Na +Both R1 and R2 are straight-chain alkanes;

[0055] The emulsifiers A and B used include the following specific types:

[0056] Emulsifier A1: Alkylphenol polyoxyethylene ether;

[0057] Emulsifier A2: Polyoxyethylene (30) dimerized hydroxystearate;

[0058] Emulsifier B1: Both R1 and R2 are C 10 H 21 n, m, and p are all 3;

[0059] Emulsifier B2: Both R1 and R2 are C 12 H 25 n, m, and p are all 3;

[0060] Emulsifier B3: R1 and R2 are both C6H 13 n, m, and p are all 3;

[0061] Emulsifier B4: Both R1 and R2 are C 16 H 33 n, m, and p are all 3;

[0062] Emulsifier B5: Both R1 and R2 are C 12 H 25 m is 3, and n and p are both 2;

[0063] Emulsifier B6: Both R1 and R2 are C 12 H 25 m is 3, and n and p are both 9;

[0064] Emulsifier B7: Both R1 and R2 are C 12 H 25 n and p are both 3, and m is 2;

[0065] Emulsifier B8: Both R1 and R2 are C 12 H 25 n and p are both 3, and m is 9;

[0066] The synthetic route for emulsifier B (taking B2 as an example) is as follows:

[0067]

[0068] The reaction steps are as follows:

[0069] Step (1): Dissolve dodecylamine in ethanol, heat in an oil bath to 70°C, add a certain amount of 1,3-dibromopropane dropwise using a constant pressure funnel under magnetic stirring, and after reacting for 6 hours, evaporate the solvent to obtain the intermediate product.

[0070] Step (2) Dissolve the intermediate product in methanol, add 1,3-propanesulfonyl lactone, react at 55°C for 12 h, neutralize the reactants with sodium carbonate, and evaporate the solvent to obtain emulsifier B2.

[0071] The ratio of dodecylamine: 1,3-dibromopropane: 1,3-propanesulfonyl lactone: sodium carbonate is 2:1.2:2.2:2.

[0072] Based on the above synthetic route, other emulsifiers B can be obtained by changing the number of carbon atoms in the raw materials.

[0073] Table 1. Equipment List

[0074]

[0075] Test method:

[0076] High-temperature stability test: Place the prepared sample in a vial, cover it, and place it in an oven at 140℃. After a specified time, take it out and observe the demulsification.

[0077] Demulsification rate determination: The demulsification rate was determined using an emulsion stability analyzer.

[0078] The following examples and comparative examples are described in detail with reference to dosage.

[0079] Preparation Example 1

[0080] Emulsifier A2 and emulsifier B2 are mixed to obtain emulsifier composition S1, wherein the mass ratio of emulsifier A2 to emulsifier B2 is 3:1.

[0081] Preparation Example 2-14

[0082] Emulsifier compositions were prepared according to the method of Preparation Example 1, except that the types and amounts of emulsifier A and emulsifier B were different from those in Preparation Example 1, resulting in emulsifier compositions S2-S14, as shown in Table 2.

[0083] Comparative Preparation Example 1

[0084] The emulsifier composition was prepared according to the method of Preparation Example 1, except that emulsifier A1 was used instead of emulsifier A2, and emulsifier B2 was not contained, resulting in emulsifier composition D1.

[0085] Comparative Preparation Example 2

[0086] The emulsifier composition was prepared in accordance with the method of Preparation Example 1, except that it did not contain emulsifier B2, thus obtaining emulsifier composition D2.

[0087] Comparative preparation example 3

[0088] The emulsifier composition was prepared according to the method of Preparation Example 1, except that emulsifier B1 was used instead of emulsifier B2, and emulsifier A2 was not contained, resulting in emulsifier composition D3.

[0089] Comparative preparation example 4

[0090] The emulsifier composition was prepared in accordance with the method of Preparation Example 1, except that it did not contain emulsifier A2, thus obtaining emulsifier composition D4.

[0091] Comparative preparation example 5

[0092] The emulsifier composition was prepared according to the method of Preparation Example 1, except that emulsifier A2 was replaced by emulsifier A3 to obtain emulsifier composition D5, wherein emulsifier A3 was Tween 20 (Sinopharm Chemical Reagent Co., Ltd.).

[0093] Comparative preparation example 6

[0094] The emulsifier composition was prepared according to the method of Preparation Example 1, except that emulsifier B9 was used to replace emulsifier B3 to obtain emulsifier composition D6, wherein emulsifier B9 was surfactant JZ-12 prepared in the literature "Research progress of Gemini surfactant compound system (Guangdong Chemical Industry, 2014, 3, 41: (67-69))".

[0095] Table 2

[0096]

[0097]

[0098] Example 1

[0099] Measure 40 mL of diesel oil and add 1 g of emulsifier composition S1. Heat and stir in a 50°C water bath until completely dissolved. After cooling to room temperature, place in a two-necked flask and add 60 mL of 20 wt% HCl solution dropwise using a disposable syringe while stirring at high speed. After all the solution has been added, stir for another 30 min to obtain emulsified acid. The amounts of each substance in the emulsified acid system are shown in Table 3.

[0100] The emulsified acid was placed in an oven at 140℃ for 2 days, the emulsion morphology was observed, and the demulsification rate was determined. The results are shown in Table 3.

[0101] Example 2

[0102] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S2 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0103] Example 3

[0104] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S3 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0105] Example 4

[0106] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S4 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0107] Example 5

[0108] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S5 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0109] Example 6

[0110] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S6 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0111] Example 7

[0112] Emulsified acid was prepared according to the method in Example 1, except that the mass concentration of the HCl solution used was 25 wt%. The test results are shown in Table 3.

[0113] Example 8

[0114] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S7 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0115] Example 9

[0116] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S8 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0117] Example 10

[0118] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S9 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0119] Example 11

[0120] Emulsified acids were prepared according to the method of Example 1, except that emulsifier composition S10 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0121] Example 12

[0122] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S11 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0123] Example 13

[0124] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S12 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0125] Example 14

[0126] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S13 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0127] Example 15

[0128] Emulsified acid was prepared according to the method of Example 1, except that emulsifier composition S14 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0129] Example 16

[0130] The emulsified acid was prepared according to the method in Example 1, except that the amount of emulsifier composition S1 used was 0.4 g. The test results are shown in Table 3.

[0131] Example 17

[0132] Emulsified acid was prepared according to the method in Example 1, except that the amount of emulsifier composition S1 was 2g and the mass concentration of the HCl solution used was 12%. The test results are shown in Table 3.

[0133] Comparative Example 1

[0134] Emulsified acids were prepared according to the method of Example 1, except that emulsifier composition D1 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0135] Comparative Example 2

[0136] Emulsified acids were prepared according to the method of Example 1, except that emulsifier composition D2 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0137] Comparative Example 3

[0138] Emulsified acids were prepared according to the method of Example 1, except that emulsifier composition D3 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0139] Comparative Example 4

[0140] Emulsified acids were prepared according to the method of Example 1, except that emulsifier composition D4 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0141] Comparative Example 5

[0142] Emulsified acids were prepared according to the method of Example 1, except that emulsifier composition D5 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0143] Comparative Example 6

[0144] Emulsified acids were prepared according to the method of Example 1, except that emulsifier composition D6 was added. The amounts of each substance in this emulsified acid system and the test results are shown in Table 3.

[0145] Table 4. Composition and test results of raw materials for the emulsified acid system

[0146]

[0147] Emulsifier A is a major component, forming a wedge-shaped close-packed structure at the oil-water interface, resulting in a stable and dense interfacial film and improving the stability of the emulsified acid. Emulsifier B is a minor component with good acid resistance. Under acidic conditions, through intermolecular hydrogen bonding, emulsifier A forms a more compact arrangement at the oil-water interface. It also contains hydrophobic tail chains, which effectively enhance intermolecular cohesion, improving the viscoelasticity of the adsorption film and the stability of the emulsion. The experimental results in Table 3 show that the emulsifier composition of emulsifier A2 and emulsifier B2 has the best emulsifying effect. Under the premise of unchanged emulsifier types, the emulsified acid exhibits the best thermal stability when the mass ratio of emulsifier A:B is m(A):m(B) = 3:1. Furthermore, within a certain range, the total amount of emulsifier significantly affects emulsion stability. Increased emulsifier concentration leads to more emulsifier molecules at the oil-acid interface, resulting in a more compact film and a more stable system. In Example 17, the decrease in demulsification rate was mainly due to a reduction in acid content; the amount of emulsifier composition had little effect.

[0148] This invention uses two emulsifiers and optimizes the conditions to form a high-temperature resistant acid emulsifier. It can be stable for more than 2 days in a 25wt% HCl solution at a high temperature of 140℃, and can be used as an important additive for high-temperature emulsified acid systems.

[0149] 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. An emulsified acid system, characterized in that, The system comprises a composition of acid, oil, and emulsifier; The emulsifier composition includes the compound shown in formula (1) and a W / O type emulsifier; Equation (1) Among them, A + B + Each is independently selected from a metal cation; R1 and R2 are each independently selected from H or C6-C16 alkyl groups; n is an integer from 1 to 9; m is an integer from 1 to 9; p is an integer from 1 to 9; The W / O type emulsifier is selected from at least one of alkylphenol polyoxyethylene ether, polyoxyethylene dimer hydroxy stearate, sorbitan oleate, and polyoxyethylene oleyl alcohol ether; The mass ratio of the W / O type emulsifier to the compound is 1-7:1; Wherein, based on the volume of oil, the amount of the emulsifier composition is 0.01-0.05 g / mL, and based on H... + The amount of acid used is 5-12 mmol / mL.

2. The emulsified acid system according to claim 1, wherein, The A + B + Each is independently selected from alkali metal cations; R1 and R2 are each independently selected from C8-C14 alkyl groups; n is an integer from 3 to 7; m is an integer from 3 to 7; p is an integer from 3 to 7; The W / O type emulsifier is selected from at least one of alkylphenol polyoxyethylene ether, polyoxyethylene dihydroxy stearate, and sorbitan oleate.

3. The emulsified acid system according to claim 2, wherein, The A + B + Each independently selected from Na + or K + R1 and R2 are each independently selected from C10-C12 alkyl groups; n is an integer from 3 to 5; m is an integer from 3 to 5; p is an integer from 3 to 5. The W / O type emulsifier is selected from alkylphenol polyoxyethylene ether and / or polyoxyethylene dimer hydroxy stearate.

4. The emulsified acid system according to claim 1, characterized in that, The mass ratio of the W / O type emulsifier to the compound shown in formula (1) is 1.5-6:

1.

5. The emulsified acid system according to claim 4, characterized in that, The mass ratio of the W / O type emulsifier to the compound shown in formula (1) is 2-5:

1.

6. The emulsified acid system according to claim 1, characterized in that, Based on the volume of oil, the amount of the emulsifier composition used is 0.015-0.035 g / mL, with H... + The amount of acid used is 6-10 mmol / mL.

7. The emulsified acid system according to claim 1, characterized in that, The acid is selected from organic acids and / or inorganic acids; the oil is selected from C8-C33 oils.

8. The emulsified acid system according to claim 7, characterized in that, The acid is selected from at least one of hydrochloric acid, sulfuric acid, nitric acid, and hydrofluoric acid; the oil is selected from at least one of diesel oil, white oil, and light crude oil.

9. An emulsified acid, characterized in that, The emulsified acid is prepared from the emulsified acid system according to any one of claims 1-8.

10. A method for preparing an emulsified acid, characterized in that, The method includes: dispersing the components in the emulsified acid system according to any one of claims 1-8 evenly to obtain the emulsified acid.

11. The method for preparing emulsified acid according to claim 10, characterized in that, The method includes: dissolving the emulsifier composition in the oil, adding the acid and dispersing it evenly to obtain the emulsified acid.

12. The application of an emulsified acid system according to any one of claims 1-8 or the emulsified acid according to claim 9 in oilfield acidizing.

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