Authigenic composite acid as well as preparation method and application thereof

Abstract

The invention provides authigenic composite acid as well as a preparation method and application thereof. The authigenic composite acid comprises the following components in parts by weight: 10-30 parts of an acid generator, 1-5 parts of a catalyst and 65-90 parts of water, the acid generator comprises N-chloro-acyl amino acid ester and / or N-chloro-acyl amino acid. According to the authigenic composite acid provided by the invention, the use temperature and the acid generation efficiency of the authigenic acid can be improved, the acid rock reaction rate is reduced, the requirement on a corrosion inhibitor is reduced, the uniform acid distribution capability is improved, and the authigenic composite acid can effectively adapt to a carbonate rock salt reservoir with higher temperature.

Description

Technical Field

[0001] The invention belongs to the technical field of oilfield chemistry, and in particular relates to a self-generated composite acid and a preparation method and application thereof. Background Art

[0002] Carbonate resources are large and widely distributed, with great exploration potential. As the exploration depth becomes deeper and deeper, the reservoir temperature becomes higher and higher, most of which exceed 160°C, and even as high as 230°C. However, the previous carbonate reservoir transformation technology is mainly suitable for reservoirs with a well depth of less than 7,000 meters and a temperature below 160°C. Acid technology mainly includes ordinary hydrochloric acid, slow hydrochloric acid, emulsified acid, thickened acid, cross-linked gel acid, surfactant self-steering acid, etc., which have achieved good results in the exploration and development of carbonate reservoirs. The implementation process mostly uses slow acid fracture creation or polymer linear gel fracture creation and a combination of these acids. With the continuous deepening of exploration depth and the continuous increase in temperature, the existing acid technology and process technology are no longer suitable. In high-temperature deep wells, the existing acid system reacts too quickly, the filtration loss increases accordingly, and the acid cannot reach the front end of the fracture; at the same time, the unevenness of reservoir transformation is aggravated, and the difficulty of uniform acid distribution increases significantly. The excessively fast reaction speed causes the acid to enter the high-permeability area, and the low-permeability area cannot be effectively transformed; the higher reservoir temperature causes the previous various slow-rate acids to pose a greater threat to the integrity of the wellbore, and the existing corrosion inhibitors are also difficult to effectively protect the tubing.

[0003] Compared with other acid solutions, autogenous acid has the advantages of being non-acidic or weakly acidic at room temperature, generating acid at a certain temperature, having low corrosion rate, and low acid-rock reaction rate. It is an important way to solve the problem of slow acidification of high-temperature deep wells. Autogenous acid types include autogenous hydrofluoric acid, autogenous hydrochloric acid, autogenous organic acid, and composite autogenous acid. Among them, autogenous hydrofluoric acid refers to an autogenous acid system that produces hydrofluoric acid as the main component after hydrolysis; autogenous hydrochloric acid is the most studied type in the field of autogenous acid. The main acid-generating agent contains chlorinated hydrocarbons and chloride salts, and hydrochloric acid is produced by hydrolysis. For example, polyformaldehyde + chloride salt is the most used autogenous acid system at present; the hydrolysis acid-generating mechanism of autogenous organic acid is the nucleophilic substitution reaction of esters, which generates corresponding organic carboxylic acids and alcohol substances, and has a good slowing effect; composite autogenous acid utilizes the synergistic effect of two or more autogenous acids, such as the autogenous acid system of formaldehyde, ammonium fluoride and organic carboxylate coexisting reported by Qu Qiansheng et al.

[0004] 202110800157.2 discloses a safe, environmentally friendly, high-temperature resistant solid organic acid system for oilfield acidification, which is composed of 80-90% modified organic anhydride, 3-10% hydrolysis catalyst and 5-10% stabilizer, and can be hydrolyzed into organic acid at an experimental temperature of 90°C. 201210169268.9 discloses a self-generated acid system; it is composed of ZX-339 and ZX-368 components, and can produce 19% to 21% hydrochloric acid at a reaction temperature of 70°C to 100°C. 201910285235.2 discloses a self-generated acid for oil and gas field acidification and fracturing, including polyformaldehyde, ammonium chloride, (1-hydroxyhexane-1,1-diyl) diphosphonic acid, citric acid, emulsifier, acetic acid, hydrochloric acid, oil, gelling agent, and drainage agent, and the experimental temperature is 120°C.

[0005] However, the acid generation temperature of the above autogenous acid and other conventional autogenous acids is usually lower than 150°C. When the temperature reaches above 150°C, the acid is basically consumed and cannot meet the transformation requirements of high-temperature areas. For the current ultra-deep and ultra-high-temperature wells, there are still certain limitations. Therefore, how to provide an autogenous acid with a high acid generation temperature has become an urgent problem to be solved. Summary of the invention

[0006] In view of the shortcomings of the prior art, the object of the present invention is to provide a self-generated composite acid and a preparation method and application thereof. The self-generated composite acid provided by the present invention can increase the use temperature and acid generation efficiency of the self-generated acid, reduce the acid-rock reaction rate, reduce the requirements for corrosion inhibitors, improve the ability of uniform acid distribution, and effectively adapt to higher temperature carbonate salt reservoirs.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a self-generated composite acid, which comprises, by weight, 10-30 parts of an acid generator, 1-5 parts of a catalyst and 65-90 parts of water.

[0009] The acid generator includes N-chloroacyl amino acid ester and / or N-chloroacyl amino acid.

[0010] Among them, the number of parts of the acid generator can be 10 parts, 15 parts, 20 parts, 25 parts or 30 parts, etc., the number of parts of the catalyst can be 1 part, 2 parts, 3 parts, 4 parts or 5 parts, etc., and the number of parts of water can be 65 parts, 70 parts, 75 parts, 80 parts, 85 parts or 90 parts, etc., but are not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0011] The above-mentioned autogenous composite acid adopts a specific acid generator. Compared with conventional autogenous acid, the acid generator is single, the acid generation efficiency is high, and it is easy to use. The hydrolysis product is not a single hydrochloric acid or organic acid, but a mixture of hydrochloric acid and organic acid. The acid generation temperature is high, and acid can be continuously generated at 150-200°C, which is suitable for ultra-high temperature reservoirs. At the same time, it ensures a low corrosion rate under medium and low temperature conditions, and has high acid generation efficiency. + The maximum concentration can reach 4.3mol / L, ensuring a high acid rock dissolution efficiency; when used in combination with conventional fracturing fluids to form autogenous acid fracturing fluids, it can not only achieve the effect of fracturing fluid volume transformation, but also achieve the effect of acidification. The autogenous acid can reach the top of the crack along with the fracturing fluid, thereby achieving the purpose of uniform acid distribution.

[0012] Preferably, the catalyst comprises any one of bromide salt, iodide salt, tetramethylammonium bromide or tetramethylammonium iodide, or a combination of at least two thereof, preferably bromide salt and / or iodide salt.

[0013] Preferably, the bromide salt comprises potassium bromide and / or sodium bromide.

[0014] Preferably, the iodide salt comprises potassium iodide and / or sodium iodide.

[0015] Preferably, the N-chloroacyl amino acid ester is prepared by a method comprising the following steps:

[0016] Mixing the chlorine organic acid and the amino organic acid for reaction to obtain the first product, N-chloroacyl amino acid ester;

[0017] The structural formula of the chlorine organic acid is ClC m H 2m COOH, the structural formula of the amino organic acid is H2NC n H 2n COOH, wherein m, n are independently selected from 1, 2 or 3.

[0018] Preferably, the N-chloroacylamino acid is prepared by a method comprising the following steps:

[0019] The first product, N-chloroacyl amino acid ester, is mixed with water and hydrolyzed to obtain the second product, N-chloroacyl amino acid.

[0020] Preferably, the molar ratio of the chlorine organic acid to the amino organic acid is (0.8-1.2):(0.8-1.2), wherein the proportion of the chlorine organic acid can be 0.8, 0.9, 1, 1.1 or 1.2, etc., and the proportion of the amino organic acid can be 0.8, 0.9, 1, 1.1 or 1.2, etc., but are not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0021] Preferably, the reaction pressure is 2000-3000 Pa, the temperature is 90-110° C., and the reaction time is 3-5 h.

[0022] Among them, the pressure can be 2000Pa, 2100Pa, 2200Pa, 2300Pa, 2400Pa, 2500Pa, 2600Pa, 2700Pa, 2800Pa, 2900Pa or 3000Pa, etc., the temperature can be 90°C, 95°C, 100°C, 105°C or 110°C, etc., and the time can be 3h, 3.5h, 4h, 4.5h or 5h, etc., but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0023] Preferably, the mass ratio of the first product N-chloroacyl amino acid ester to water is (3-5):(5-7).

[0024] Preferably, the hydrolysis temperature is 50-70°C and the time is 7-9h.

[0025] Among them, in the mass ratio of the first product N-chloroacyl amino acid ester to water, the number of parts of the first product N-chloroacyl amino acid ester can be 3, 3.5, 4, 4.5 or 5, the mass ratio of water can be 5, 5.5, 6, 6.5 or 7, the hydrolysis temperature can be 50°C, 55°C, 60°C, 65°C or 70°C, and the time can be 7h, 7.5h, 8h, 8.5h or 9h, but are not limited to the above-listed values, and other unlisted values ​​within the above numerical range are also applicable.

[0026] Preferably, the hydrolysis temperature of the self-generated composite acid is 120-200°C, the acid generation time is 1-24h, and the hydrogen ion concentration is 0.5-4.2mol / L, wherein the hydrolysis temperature can be 120°C, 130°C, 140°C, 150°C, 160°C, 170°C, 180°C, 190°C or 200°C, etc., and the acid generation time can be 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h, 10h, 11h, 12h, 13h , 14h, 15h, 16h, 17h, 18h, 19h, 20h, 21h, 22h, 23h or 24h, etc., the hydrogen ion concentration can be 0.5mol / L, 1mol / L, 1.5mol / L, 2mol / L, 2.5mol / L, 3mol / L, 3.5mol / L, 4mol / L or 4.2mol / L, etc., but is not limited to the values ​​listed above, and other values ​​not listed within the above numerical range are also applicable.

[0027] In a second aspect, the present invention provides a method for preparing the self-generated composite acid as described above, characterized in that the preparation method comprises the following steps:

[0028] The self-generated composite acid is obtained by mixing and stirring an acid generator, a catalyst and water.

[0029] In a third aspect, the present invention also provides the use of the above-mentioned autogenous composite acid in oil field acidification transformation.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The invention provides a self-generated composite acid. By adopting a specific acid generator, compared with conventional self-generated acid, the acid generator is single, the acid generation efficiency is high, and the use is convenient. The hydrolysis product is not a single hydrochloric acid or an organic acid, but a mixture of hydrochloric acid and an organic acid. The acid generation temperature is high, and the acid can be continuously generated under the condition of 150-200°C, which is suitable for ultra-high temperature reservoirs. At the same time, a low corrosion rate is guaranteed under medium and low temperature conditions, the acid generation efficiency is high, and H + The maximum concentration can reach 4.3mol / L, ensuring a high acid rock dissolution efficiency; when used in combination with conventional fracturing fluids to form autogenous acid fracturing fluids, it can not only achieve the effect of fracturing fluid volume transformation, but also achieve the effect of acidification. The autogenous acid can reach the top of the crack along with the fracturing fluid, thereby achieving the purpose of uniform acid distribution. DETAILED DESCRIPTION

[0032] In order to further explain the technical means and effects adopted by the present invention, the technical solution of the present invention is further described below in conjunction with the preferred embodiments of the present invention, but the present invention is not limited to the scope of the embodiments.

[0033] Example 1

[0034] This embodiment provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0035] Chloroacetic acid and aminoacetic acid were mixed in a 1:1 molar ratio in a closed container, placed at a pressure of 2500 Pa and a temperature of 100° C., and reacted for 4 hours under stirring to obtain a first product, which was an N-chloroacetylglycine ester acid generator (the first products of the subsequent examples and comparative examples were synthesized according to this method).

[0036] The acid generator, the acid generating catalyst potassium bromide and water are mixed and stirred in a mass ratio of 30:3:67 to obtain the self-generated composite acid.

[0037] Example 2

[0038] This embodiment provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0039] Chloroacetic acid and aminoacetic acid are mixed in a molar ratio of 1:1, and reacted to obtain a first product which is an N-chloroacetylglycine ester acid generator.

[0040] The acid generator, the acid generating catalyst potassium iodide and water are mixed and stirred in a mass ratio of 30:3:67 to obtain the self-generated composite acid.

[0041] Example 3

[0042] This embodiment provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0043] Chloroacetic acid and aminoacetic acid are reacted in a molar ratio of 1:1 to obtain a first product, which is an N-chloroacetylglycine ester acid generator. The first product is dissolved in water, the first product and water are mixed and stirred in a mass ratio of 4:6, the temperature is raised to 60°C, and hydrolyzed for 8 hours to obtain a second product, N-chloroacetylglycine acid generator (the second products of the subsequent examples and comparative examples are synthesized according to this method).

[0044] The second product, the acid-generating catalyst potassium bromide and water are mixed and stirred in a mass ratio of 30:3:67 to obtain the self-generated composite acid.

[0045] Example 4

[0046] This embodiment provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0047] Chloroacetic acid and aminopropionic acid are mixed in a molar ratio of 1:1 and reacted to obtain a first product, which is an N-chloroacetylalanine ester acid generator.

[0048] The acid generator, the acid generating catalyst potassium iodide and water are mixed and stirred in a mass ratio of 30:3:67 to obtain the self-generated composite acid.

[0049] Example 5

[0050] This embodiment provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0051] The ethyl chloride and the aminopropyl are mixed in a 1:1 molar ratio, and reacted to obtain a first product, which is an N-chloroacetylalanine ester acid generator, which is further hydrolyzed to obtain a second product, an N-chloroacetylalanine acid generator.

[0052] The second product, the acid-generating catalyst potassium bromide and water are mixed and stirred in a mass ratio of 30:3:67 to obtain the self-generated composite acid.

[0053] Example 6

[0054] This embodiment provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0055] Chlorobutyric acid and aminoacetic acid are mixed in a molar ratio of 1:1 and reacted to obtain a first product, which is an N-chlorobutyryl alanine ester acid generator.

[0056] The acid generator, the acid generating catalyst potassium bromide and water are mixed and stirred in a mass ratio of 30:3:67 to obtain the self-generated composite acid.

[0057] Comparative Example 1

[0058] This comparative example provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0059] Chloroacetic acid and aminoacetic acid are mixed in a molar ratio of 1:1, and reacted to obtain a first product which is an N-chloroacetylglycine ester acid generator.

[0060] The acid generator and water are mixed and stirred in a mass ratio of 30:70 to obtain the self-generated composite acid.

[0061] Comparative Example 2

[0062] This comparative example provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0063] Chloroacetic acid and aminoacetic acid are mixed in a molar ratio of 1:1 to react to obtain a first product, N-chloropropionyl glycine ester; further hydrolysis is performed to obtain a second product, N-chloroacetyl glycine acid generator.

[0064] The second product and water are mixed and stirred in a mass ratio of 30:70 to obtain the autogenous composite acid.

[0065] Comparative Example 3

[0066] This comparative example provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0067] Chloroacetic acid and aminovaleric acid are mixed in a molar ratio of 1:1, and reacted to obtain a first product, which is an N-chloroacetylvaleric acid ester acid generator.

[0068] The acid generator, the acid generating catalyst potassium bromide and water are mixed and stirred in a mass ratio of 30:3:67 to obtain the self-generated composite acid.

[0069] Comparative Example 4

[0070] This comparative example provides a self-generated composite acid and a preparation method, which is prepared by the following method:

[0071] Chlorovaleric acid and aminoacetic acid are mixed in a molar ratio of 1:1, and reacted to obtain a first product which is an N-chlorovalerylglycine ester acid generator.

[0072] The acid generator, the acid generating catalyst potassium bromide and water are mixed and stirred in a mass ratio of 30:3:67 to obtain the self-generated composite acid.

[0073] The autogenous composite acid provided in the above embodiments and comparative examples was subjected to a simulation test. The autogenous composite acid was heated from 20°C to the following table temperatures and kept warm. At the end of each temperature stage, samples were taken for testing. The hydrogen ion concentration (mol / L) was tested. The results are as follows:

[0074] Group Acid generation temperature, ℃ Acid generation time, h Acid concentration, mol / L Example 1 90 3 0.05 Example 1 120 3 1.09 Example 1 150 3 2.52 Example 1 200 3 4.28 Example 2 120 3 0.53 Example 2 200 3 3.81 Example 3 120 3 1.09 Example 3 200 3 3.92 Example 4 200 3 3.35 Example 5 200 3 3.75 Example 6 200 3 2.87 Comparative Example 1 200 3 1.55 Comparative Example 2 200 3 1.41 Comparative Example 3 200 3 2.13 Comparative Example 4 200 3 1.61

[0075] From the above data, it can be found that the self-generated composite acid provided by the present invention can still continuously generate acid under the condition of 150-200°C, which is suitable for ultra-high temperature reservoirs, while ensuring a low corrosion rate under medium and low temperature conditions, and having high acid generation efficiency; from the examples, it can be seen that the acid generator is preferably chloroacetic acid and aminoacetic acid, and the catalyst is preferably potassium bromide; compared with the solution using other acid generators and no catalyst in the comparative example, the present invention can further improve the effect of the product and increase H + The concentration can be reduced, and the acid distribution effect is more uniform, which is more conducive to the transformation of ultra-high temperature reservoirs.

[0076] The applicant declares that the present invention illustrates the self-generated composite acid and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned embodiments, that is, it does not mean that the present invention must rely on the above-mentioned embodiments to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of various raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

[0077] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0078] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

Claims

1. A self-generated composite acid, characterized in that: The self-generated composite acid comprises 10-30 parts of an acid generating agent, 1-5 parts of a catalyst and 65-90 parts of water in parts by weight; The acid generator includes N-chloroacyl amino acid ester and / or N-chloroacyl amino acid.

2. The autogenous composite acid according to claim 1, characterized in that: The catalyst comprises any one of bromide salt, iodide salt, tetramethylammonium bromide or tetramethylammonium iodide or a combination of at least two thereof, preferably bromide salt and / or iodide salt.

3. The self-generated composite acid according to claim 2, characterized in that: The bromide salt includes potassium bromide and / or sodium bromide; Preferably, the iodide salt comprises potassium iodide and / or sodium iodide.

4. The autogenous composite acid according to any one of claims 1 to 3, characterized in that The N-chloroacyl amino acid ester is prepared by a method comprising the following steps: Mixing the chlorine organic acid and the amino organic acid for reaction to obtain the first product, N-chloroacyl amino acid ester; The structural formula of the chlorine organic acid is ClC m H 2m COOH, the amino organic acid has the structural formula H2NC n H 2n COOH, wherein m, n are independently selected from 1, 2 or 3.

5. The autogenous composite acid according to claim 4, characterized in that: The N-chloroacylamino acid is prepared by a method comprising the following steps: The first product, N-chloroacyl amino acid ester, is mixed with water and hydrolyzed to obtain the second product, N-chloroacyl amino acid.

6. The autogenous composite acid according to claim 4, characterized in that: The molar ratio of the chlorine organic acid to the amino organic acid is (0.8-1.2):(0.8-1.2); Preferably, the reaction pressure is 2000-3000 Pa, the temperature is 90-110° C., and the reaction time is 3-5 h.

7. The autogenous composite acid according to claim 5, characterized in that: The mass ratio of the first product N-chloroacyl amino acid ester to water is (3-5):(5-7); Preferably, the hydrolysis temperature is 50-70°C and the time is 7-9h.

8. The autogenous composite acid according to any one of claims 1 to 7, characterized in that: The hydrolysis temperature of the self-generated composite acid is 120-200° C., the acid generation time is 1-24 hours, and the hydrogen ion concentration is 0.5-4.2 mol / L.

9. A method for preparing a self-generated composite acid according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: The self-generated composite acid is obtained by mixing and stirring an acid generator, a catalyst and water.

10. Use of the autogenous composite acid according to any one of claims 1 to 8 in oil field acidification transformation.