A novel method for preparing targeted autogenous acid for ultra-high temperature formations

Abstract

The invention discloses a preparation method for a novel targeted autogenous acid applied to ultra-high temperature formations, relates to the field of oil and gas field development, and solves the problem of premature release of autogenous acid during injection. The method comprises the following steps: performing a first reaction in deionized water containing ammonium chloride or organic ammonium chloride to obtain a surface-modified porous carbon material; performing a second reaction in deionized water containing a polyol with the surface-modified porous carbon material as a core to obtain a dispersed phase; adding an emulsifier to the oil phase and the dispersed phase to form an oil-in-water emulsion after dispersion, and then adding epichlorohydrin to perform a third reaction to obtain agent A; taking a carbonyl compound as agent B, mixing agent A and agent B to obtain a novel targeted autogenous acid; the autogenous acid of the invention can be applied to a formation environment at 180°C, has relatively stable acid generation performance, and simultaneously, the autogenous acid begins to slowly release acid at 160°C and releases a large amount of acid at 180°C, having good targeting performance.

Description

Technical Field

[0001] The present invention relates to the technical field of oil and gas field development, and more particularly to the technical field of reservoir transformation working fluids for high-temperature formations. Background Art

[0002] With the continued development of oil and gas well engineering, the number of deep and ultra-deep wells has gradually increased, and bottomhole temperatures have also risen, thus increasing the requirements for oil and gas field development. At the same time, as development continues to deepen, the development of fractures and vugs in oil and gas reservoirs has also deteriorated, necessitating the development of acidizing engineering. Currently, acid systems mainly include cross-linked acid, emulsified acid, and diverting acid. However, due to the rapid reaction rate of the main acid, HCl, with rock and the limited range of action, it is difficult to apply in deep formation environments.

[0003] Autogenous acid is a chemical reagent that reacts slowly in the formation environment to produce organic or inorganic acids, which acidify the rock. Compared to other types of acid, the active acid content in the autogenous acid system is low due to the low temperature during injection into the wellbore. Therefore, the acidity is weak and the corrosion rate of downhole equipment such as the tubing string is very low. Furthermore, because the active acid is produced by a gradual reaction (primarily hydrolysis) of the autogenous acid and then reacts with the formation rock, it does not experience the rapid deactivation of hydrochloric acid. Therefore, autogenous acid is ideally suited as a working fluid for reservoir reconstruction in high-temperature formations, ensuring the required long-range rock corrosion. However, the use of autogenous acid does have certain limitations. As temperature increases, molecular thermal motion intensifies, accelerating the autogenous acid reaction. This also leads to the need for large amounts of autogenous acid in high-temperature formations, which undoubtedly increases the cost of on-site operations.

[0004] CN202011010497.7 discloses a polychloroether alcohol autoacidifier and its use method, comprising polychloroether alcohol, a low-temperature inhibitor, and a medium-temperature catalyst and / or a high-temperature accelerator. The method primarily achieves deep-penetrating acid fracturing in high-temperature formations by adding the low-temperature inhibitor, medium-temperature catalyst, and high-temperature accelerator to the polychloroether alcohol to adjust the acid generation rate at different temperatures.

[0005] CN201911217569.2 discloses a low-toxic solid-liquid mixed autogenous acid system and a method for acidifying high-temperature carbonate reservoirs. The solid-liquid mixed autogenous acid system includes a liquid system and a solid tablet. The liquid system is an organic acid vinyl ester and water, and the solid tablet includes a weak acid ammonium salt, guar gum, sucrose, and magnesium stearate. It mainly uses chemical reagents such as organic acid vinyl ester, weak acid ammonium salt, and guar gum to react and generate acid in the formation to corrode the formation.

[0006] CN201910359803.9 discloses a polychlorinated ketone alcohol autoacidifier and a method for using the same. The polychlorinated ketone alcohol autoacidifier comprises polychlorinated ketone alcohol, a low-temperature inhibitor, and a medium-temperature catalyst and / or a high-temperature accelerator. The medium-temperature catalyst is an alkaline compound, the low-temperature inhibitor is a hydrocarbon compound, and the high-temperature accelerator is an organic compound. The method mainly achieves the effect of deep penetrating acid fracturing of high-temperature formations by adjusting the acid generation rate at different temperatures by adding a low-temperature inhibitor, a medium-temperature catalyst, and a high-temperature accelerator to polychlorinated ketone alcohol.

[0007] The above patent only alleviates the decomposition of the autogenous acid, but still does not truly solve the problem of the rapid reaction of the autogenous acid at high temperature. Summary of the Invention

[0008] The purpose of the present invention is to solve the technical problem of premature release of authigenic acid during the injection process. The present invention provides a novel method for preparing targeted authigenic acid for use in ultra-high temperature formations.

[0009] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0010] A method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations comprises the following steps:

[0011] Step 1: Using a porous carbon material as a hard template, a first reaction is carried out in deionized water containing ammonium chloride or organic ammonium chloride, and a surface-modified porous carbon material is obtained after drying;

[0012] Step 2: Using the surface-modified porous carbon material as the core, a second reaction is carried out in deionized water containing a polyol to prepare a dispersed phase;

[0013] Step 3: adding an emulsifier to the oil phase, and then adding the dispersed phase under a nitrogen atmosphere to form a water-in-oil emulsion after dispersion. Then, epichlorohydrin is added to the water-in-oil emulsion to carry out a third reaction, and the mixture is filtered and freeze-dried to obtain a microcapsule-encapsulated surface-modified porous carbon material, i.e., Agent A.

[0014] Step 4: Using the carbonyl compound as agent B, agent A and agent B are mixed to obtain a new type of targeted autogenous acid AGA.

[0015] In the technical solution of the present application: porous carbon material can take advantage of its large specific surface area and excellent adsorption performance as a good template and adsorbent to adsorb and carry ammonium chloride or organic ammonium chloride, freeze-dry, and form a surface-modified porous carbon material. At the same time, polyol and epichlorohydrin are used to form a polymer film on the surface of the surface-modified porous carbon material through a condensation reaction to obtain agent A, and at the same time, it is mixed with agent B (carbonyl compound) to obtain a new targeted autogenous acid AGA. The polymer film structure of the present application prevents ammonium chloride or organic ammonium chloride from reacting with carbonyl compounds in advance to generate autogenous acid. Agent A will release surface-modified porous carbon material in a specific formation at high temperature, and the ammonium chloride or organic ammonium chloride loaded thereon will contact the carbonyl compound in the liquid to undergo a nucleophilic addition reaction to release acid. The autogenous acid of the present application can be applied to a formation environment of 180°C and has relatively stable acid-generating performance. At the same time, the autogenous acid AGA starts to slowly release acid at 160°C and releases a large amount of acid at 180°C, with good targeting performance.

[0016] The purpose of the nitrogen atmosphere in this application is to remove oxygen and prevent oxidation from affecting the reaction and the reaction products.

[0017] Preferably, the porous carbon material includes any one of activated carbon, activated carbon fiber, expanded graphite, and micro-nano porous carbon material.

[0018] Preferably, the concentration of the deionized water solution containing ammonium chloride is 10 w / v% to 30 w / v%.

[0019] More preferably, the concentration of the deionized water solution containing ammonium chloride is 20 w / v% to 28 w / v%.

[0020] Preferably, the concentration of the deionized water solution containing organic ammonium chloride is 10 w / v% to 30 w / v%.

[0021] More preferably, the concentration of the deionized water solution containing organic ammonium chloride is 20 w / v% to 28 w / v%.

[0022] Preferably, the volume mass ratio of the deionized water solution containing ammonium chloride to the porous carbon material is 10 mL:1-2 g.

[0023] Preferably, the volume mass ratio of the concentration of the deionized water solution containing organic ammonium chloride to the porous carbon material is 10 mL: 1-2 g.

[0024] Preferably, the organic ammonium chloride includes one or more of benzyltrimethylammonium chloride, methyltriethylammonium chloride, methyltrioctylammonium chloride, and dimethyldiallylammonium chloride.

[0025] Preferably, the conditions for the first reaction are a reaction temperature of 25 to 35° C. and a reaction time of 5 to 8 h.

[0026] Preferably, the polyol includes any one of ethylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol, and the concentration of the deionized water solution containing the polyol is 30 w / v% to 70 w / v%.

[0027] More preferably, the concentration of the deionized water solution containing the polyol is 40 w / v% to 60 w / v%.

[0028] Preferably, in step 2, the volume mass ratio of deionized water to the surface-modified porous carbon material is 20 mL:1-3 g.

[0029] Preferably, the conditions for the second reaction are a reaction temperature of 20 to 30° C. and a reaction time of 2 to 5 h.

[0030] Preferably, in step 3, the oil phase is a continuous oil phase, and the continuous oil phase includes any one of white oil, diesel, kerosene, and gasoline.

[0031] Preferably, the emulsifier includes any one of Span 60, Span 80, N,N-dimethylhexanoyl ammonium, and diglycerol monolaurate.

[0032] Preferably, the volume mass ratio of the continuous oil phase to the emulsifier is 100 mL:3-10 g.

[0033] Preferably, the volume mass ratio of the continuous oil phase to the emulsifier is 100 mL:5-9 g.

[0034] Preferably, the dispersion conditions include: magnetic stirring, reaction temperature of 20-30° C., and reaction time of 0.5-1.5 h.

[0035] Preferably, the volume mass ratio of the continuous phase oil to epichlorohydrin is 100 mL:10-30 g.

[0036] Preferably, the volume mass ratio of the continuous phase oil to epichlorohydrin is 100 mL:15-20 g.

[0037] Preferably, the conditions for the third reaction are: reaction temperature 65-85° C., reaction time 3-5 h, and stirring speed 800-1200 r / min.

[0038] Preferably, the carbonyl compound includes any one of paraformaldehyde, polyhexaldehyde, and polydimethylaminobenzaldehyde; and the mass ratio of agent A to agent B is 3.5 to 8:1.

[0039] More preferably, the mass ratio of agent A to agent B is 4 to 6:1.

[0040] Preferably, a new targeted autogenous acid is prepared by a preparation method of a new targeted autogenous acid used in ultra-high temperature formations. The new targeted autogenous acid is resistant to high temperatures of 120-180°C, and the acid concentration in 5 hours is greater than 0.1 mol / L, and the acid concentration in 24 hours is greater than 2.9 mol / L.

[0041] Preferably, the novel targeted autogenous acid is resistant to high temperatures of 150-180°C.

[0042] The beneficial effects of the present invention are as follows:

[0043] 1. Porous carbon materials can be used as good templates and adsorbents due to their large specific surface area and excellent adsorption performance to adsorb and carry ammonium chloride or organic ammonium chloride. At the same time, polyols and epichlorohydrin are used to form a polymer film on the surface of the surface-modified porous carbon material through a condensation reaction. This polymer film structure prevents ammonium chloride or organic ammonium chloride from reacting with carbonyl compounds to generate autogenous acid in advance.

[0044] 2. Agent A will release surface-modified porous carbon materials in specific formations at high temperatures. The ammonium chloride or organic ammonium chloride loaded on the carbonyl compounds in the liquid will react with the carbonyl compounds in the liquid to produce a nucleophilic addition reaction and release acid.

[0045] 3. The novel targeted autogenous acid of the present application is resistant to high temperatures of 120-180°C. Preferably, the novel targeted autogenous acid is resistant to high temperatures of 150-180°C. The acid concentration after 5 hours is greater than 0.1 mol / L, and the acid concentration after 24 hours is greater than 2.9 mol / L.

[0046] 4. Autogenous acid can be used in a formation environment of 180°C and has relatively stable acid generation performance. At the same time, autogenous acid AGA begins to slowly release acid at 160°C and releases a large amount of acid at 180°C, with good targeting performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a flow chart of a method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations according to the present invention;

[0048] Figure 2 It is the acid-generating concentration of AGA-3 within 12 hours of autogenerating acid at different temperatures. DETAILED DESCRIPTION

[0049] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0050] Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work shall fall within the scope of protection of the present invention.

[0051] Example 1

[0052] like Figure 1 As shown, this embodiment provides a method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations, comprising the following steps:

[0053] (1) 54.2 g of ammonium chloride powder was slowly added to 200 mL of deionized water and stirred to dissolve, followed by the addition of 39.5 g of activated carbon. The mixture was allowed to stand at 35 °C for 8 h and freeze-dried at -50 °C and 9 Pa to obtain a surface-modified porous carbon material.

[0054] (2) Add 24 g of ethylene glycol to 40 mL of deionized water, and add 5.8 g of surface-modified porous carbon material, and let it stand at 30°C for 5 h to complete the preparation of the dispersed phase.

[0055] (3) 22.5 g of Span 80 was added to 250 mL of white oil. The solution was clarified under a nitrogen atmosphere and magnetic stirring. The dispersed phase prepared in step (2) was then added thereto. The mixture was magnetically stirred to form a water-in-oil emulsion. 50 g of epichlorohydrin was then added thereto. The mixture was reacted at 85° C. and 1200 rpm for 5 h. The mixture was filtered and freeze-dried at -50° C. and 9 Pa to obtain Agent A. At the same time, 5.2 g of Agent A and 0.85 g of paraformaldehyde (Agent B) were weighed to form a novel targeted autogenous acid AGA-1 (Autogenous Acid-1).

[0056] Example 2

[0057] like Figure 1 As shown, this embodiment provides a method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations, comprising the following steps:

[0058] (1) 37.2 g of ammonium chloride powder was slowly added to 180 mL of deionized water and stirred to dissolve, followed by the addition of 18.5 g of activated carbon fiber. The mixture was allowed to stand at 25 °C for 5 h and freeze-dried at -50 °C and 9 Pa to obtain a surface-modified porous carbon material.

[0059] (2) Add 20 g of 1,4-butanediol and 2.6 g of surface-modified porous carbon material to 50 mL of deionized water and let it stand at 20 °C for 2 h to complete the preparation of the dispersed phase.

[0060] (3) 15.1 g of Span 60 was added to 300 mL of kerosene. Under a nitrogen atmosphere, the solution was clarified under magnetic stirring. The dispersed phase prepared in step (2) was then added thereto. The mixture was magnetically stirred to form a water-in-oil emulsion. 46.2 g of epichlorohydrin was then added thereto. The mixture was reacted at 65°C and 800 rpm for 3 h. The mixture was filtered and freeze-dried at -50°C and 9 Pa to obtain Agent A. Meanwhile, 10.8 g of Agent A and 2.7 g of polyhexaldehyde (Agent B) were weighed to form a novel targeted autogenous acid AGA-2 (autogenous acid-2).

[0061] Example 3

[0062] like Figure 1 As shown, this embodiment provides a method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations, comprising the following steps:

[0063] (1) 52.8 g of ammonium chloride powder was slowly added to 220 mL of deionized water and stirred to dissolve, followed by the addition of 33.4 g of expanded graphite. The mixture was allowed to stand at 30 °C for 6 h and freeze-dried at -50 °C and 9 Pa to obtain a surface-modified porous carbon material.

[0064] (2) 17.6 g of 1,6-butanediol and 3.5 g of surface-modified porous carbon material were added to 35 mL of deionized water and allowed to stand at 25 °C for 3.5 h to complete the preparation of the dispersed phase.

[0065] (3) 19.6 g of N,N-dimethylhexanoyl ammonium was added to 280 mL of diesel, and the solution was clarified under a nitrogen atmosphere and magnetic stirring. The dispersed phase prepared in step (2) was then added thereto, and magnetic stirring was performed to form a water-in-oil emulsion. Subsequently, 47.6 g of epichlorohydrin was added thereto, and the mixture was reacted at 75°C and 1000 r / min for 4 h. The mixture was filtered and freeze-dried at -50°C and 9 Pa to obtain Agent A. At the same time, 13.8 g of Agent A and 2.76 g of polydimethylaminobenzaldehyde (Agent B) were weighed to form a new targeted autogenous acid AGA-3 (Autogenous Acid-3).

[0066] Example 4

[0067] like Figure 1 As shown, this embodiment provides a method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations, comprising the following steps:

[0068] (1) Slowly add 59.8 g of ammonium chloride powder to 200 mL of deionized water and stir to dissolve it. Then add 31.5 g of micro-nano porous carbon material, let it stand at 33 ° C for 5.3 h, and freeze-dry at -50 ° C, 9 Pa to obtain a surface-modified porous carbon material.

[0069] (2) 31.5 g of neopentyl glycol and 5.85 g of surface-modified porous carbon material were added to 45 mL of deionized water and allowed to stand at 28 °C for 2.5 h to complete the preparation of the dispersed phase.

[0070] (3) 26.6 g of diglycerol monolaurate was added to 280 mL of gasoline. The solution was clarified under a nitrogen atmosphere and magnetic stirring. The dispersed phase prepared in step (2) was then added thereto. The mixture was magnetically stirred to form a water-in-oil emulsion. 81.2 g of epichlorohydrin was then added thereto. The mixture was reacted at 80° C. and 850 rpm for 4.5 h. The mixture was filtered and freeze-dried at -50° C. and 9 Pa to obtain Agent A. At the same time, 12.2 g of Agent A and 1.56 g of polyhexaldehyde (Agent B) were weighed to form a novel targeted autogenous acid AGA-4 (autogenous acid-4).

[0071] Example 5

[0072] like Figure 1 As shown, this embodiment provides a method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations, comprising the following steps:

[0073] (1) 21.8 g of methyltriethylammonium chloride powder was slowly added to 200 mL of deionized water and stirred to dissolve, followed by the addition of 21 g of expanded graphite. The mixture was allowed to stand at 27 °C for 7.5 h and freeze-dried at -50 °C and 9 Pa to obtain a surface-modified porous carbon material.

[0074] (2) Add 12.5 g of ethylene glycol to 40 mL of deionized water and add 2.2 g of surface-modified porous carbon material, and let it stand at 21°C for 4.5 h to complete the preparation of the dispersed phase.

[0075] (3) 8.0 g of Span 80 was added to 250 mL of white oil. The solution was clarified under a nitrogen atmosphere and magnetic stirring. The dispersed phase prepared in step (2) was then added thereto. The mixture was magnetically stirred to form a water-in-oil emulsion. 30 g of epichlorohydrin was then added thereto. The mixture was reacted at 60° C. and 1100 rpm for 2.5 h. The mixture was filtered and freeze-dried at -50° C. and 9 Pa to obtain Agent A. Meanwhile, 13.8 g of Agent A and 3.63 g of paraformaldehyde (Agent B) were weighed to form a novel targeted autogenous acid AGA-5 (Autogenous Acid-5).

[0076] Example 6

[0077] like Figure 1 As shown, this embodiment provides a method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations, comprising the following steps:

[0078] (1) 44.5 g of dimethyldiallylammonium chloride powder was slowly added to 200 mL of deionized water and stirred to dissolve. Then, 24.2 g of activated carbon was added and allowed to stand at 28 °C for 6.5 h. The surface-modified porous carbon material was obtained by freeze-drying at -50 °C and 9 Pa.

[0079] (2) Add 21 g of 1,6-hexanediol to 50 mL of deionized water and add 4.8 g of surface-modified porous carbon material. Let it stand at 25 °C for 2.8 h to complete the preparation of the dispersed phase.

[0080] (3) 12.6 g of Span 60 was added to 300 mL of gasoline. Under a nitrogen atmosphere, the solution was clarified under magnetic stirring. The dispersed phase prepared in step (2) was then added thereto. After magnetic stirring, a water-in-oil emulsion was formed. Subsequently, 43.5 g of epichlorohydrin was added thereto. The mixture was reacted at 70° C. and 900 rpm for 4.7 h. The mixture was filtered and freeze-dried at -50° C. and 9 Pa to obtain Agent A. Simultaneously, 18.5 g of Agent A and 2.81 g of polydimethylaminobenzaldehyde (Agent B) were weighed to form a novel targeted autogenous acid AGA-6 (autogenous acid-6).

[0081] Example 7

[0082] like Figure 1 As shown, this embodiment provides a method for preparing a novel targeted autogenous acid for use in ultra-high temperature formations, comprising the following steps:

[0083] (1) 36.8 g of methyl trioctyl ammonium chloride powder was slowly added to 200 mL of deionized water and stirred to dissolve. Subsequently, 25 g of expanded graphite was added and the mixture was allowed to stand at 27 °C for 7.5 h. The surface-modified porous carbon material was obtained by freeze-drying at -50 °C and 9 Pa.

[0084] (2) Add 12.5 g of neopentyl glycol to 40 mL of deionized water, and add 2.2 g of surface-modified porous carbon material, and let it stand at 21°C for 4.5 h to complete the preparation of the dispersed phase.

[0085] (3) 10.0 g of diglycerol monolaurate was added to 250 mL of white oil. The solution was clarified under a nitrogen atmosphere and magnetic stirring. The dispersed phase prepared in step (2) was then added thereto. The mixture was magnetically stirred to form a water-in-oil emulsion. 30 g of epichlorohydrin was then added thereto. The mixture was reacted at 70° C. and 900 rpm for 3 h. The mixture was filtered and freeze-dried at -50° C. and 9 Pa to obtain Agent A. At the same time, 11.8 g of Agent A and 2.63 g of polydimethylaminobenzaldehyde (Agent B) were weighed to form a novel targeted autogenous acid AGA-7 (Autogenous Acid-7).

[0086] Comparative Example 1

[0087] The method of Example 1 was followed, except that no activated carbon was added in step (1). Other conditions were the same as those of Example 1. Product D-1 was obtained.

[0088] Comparative Example 2

[0089] The method of Example 1 was followed, except that ammonium chloride was not added in step (1). Other conditions were the same as those of Example 1. Product D-2 was obtained.

[0090] Comparative Example 3

[0091] The method of Example 1 was followed, except that in step (2), the amount of ethylene glycol added was 1.5 g, and other conditions were the same as those of Example 1. Product D-3 was obtained.

[0092] Comparative Example 4

[0093] The method of Example 1 was followed, except that in step (2), the amount of surface-modified porous carbon material added was 12.1 g, and other conditions were the same as those of Example 1. Product D-4 was obtained.

[0094] Comparative Example 5

[0095] The method of Example 5 was followed, except that in step (3), the amount of epichlorohydrin added was 15.4 g, and other conditions were the same as those of Example 5. Product D-5 was obtained.

[0096] Comparative Example 6

[0097] The method of Example 5 was followed, except that in step (3), 5.2 g of Agent A and 0.1 g of paraformaldehyde (Agent B) were weighed to form authigenic acid. Other conditions were the same as those of Example 5. Product D-6 was obtained.

[0098] Comparative Example 7

[0099] The method of Example 5 was followed, except that in step (1), the amount of expanded graphite added was changed to 1.3 g, and other conditions were the same as those of Example 5 to obtain product D-7.

[0100] Test Example 1

[0101] This test example used the autogenous acid provided in Examples 1-7 and Comparative Examples 1-7 to conduct an acid-base neutralization titration experiment using a 1 mol / L NaOH solution. The acid concentration of the autogenous acid at 180°C was tested, and the results are shown in Table 1.

[0102] Table 1 Autogenous acid concentration at 180℃

[0103]

[0104] As shown in Table 1, the autogenous acid AGA can generate more than 2.9 mol / L of hydrochloric acid within 36 hours, which is better than the products obtained in Comparative Examples 1-7, indicating that AGA has excellent acid-generating performance at high temperatures.

[0105] Test Example 2

[0106] The acid concentration of AGA-3 was tested at different temperatures within 12 hours of self-acidification. The results are as follows: Figure 1 shown.

[0107] Depend on Figure 2 It can be seen that AGA-3 starts to release H at 160℃ + , but its concentration is low, only 0.04 mol / L. When the temperature rises to 180℃, H + The concentration surged to 1.48 mol / L. This indicates that the autogenous acid AGA-3 only generates acid at a specific temperature and has a certain intelligent targeting effect.

[0108] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing targeted autogenous acid for ultra-high temperature formations, characterized in that: The steps include: Step 1: Using a porous carbon material as a hard template, a first reaction is carried out in deionized water containing ammonium chloride or organic ammonium chloride, and a surface-modified porous carbon material is obtained after drying; Step 2: Using the surface-modified porous carbon material as the core, a second reaction is carried out in deionized water containing a polyol to prepare a dispersed phase; Step 3: adding an emulsifier to the oil phase, and then adding the dispersed phase under a nitrogen atmosphere to form a water-in-oil emulsion after dispersion. Then, epichlorohydrin is added to the water-in-oil emulsion to carry out a third reaction, and the mixture is filtered and freeze-dried to obtain a microcapsule-encapsulated surface-modified porous carbon material, i.e., Agent A. Step 4: Using the carbonyl compound as agent B, agent A and agent B are mixed to obtain targeted authigenic acid AGA; The carbonyl compound includes any one of paraformaldehyde, polyhexaldehyde, and polydimethylaminobenzaldehyde.

2. The method for preparing targeted autogenous acid for ultra-high temperature formations according to claim 1, characterized in that: The porous carbon material includes any one of activated carbon, activated carbon fiber, expanded graphite, and micro-nano porous carbon materials.

3. The method for preparing targeted autogenous acid for ultra-high temperature formations according to claim 1, characterized in that: The concentration of the deionized water solution containing ammonium chloride is 10 w / v% to 30 w / v%.

4. The method for preparing targeted autogenous acid for ultra-high temperature formations according to claim 3, characterized in that: The concentration of the deionized water solution containing ammonium chloride is 20 w / v% to 28 w / v%.

5. The method for preparing targeted autogenous acid for ultra-high temperature formations according to claim 1, characterized in that: The concentration of the deionized water solution containing organic ammonium chloride is 10 w / v% to 30 w / v%.

6. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 5, characterized in that: The concentration of the deionized water solution containing organic ammonium chloride is 20 w / v% to 28 w / v%.

7. The method for preparing targeted autogenous acid for ultra-high temperature formations according to claim 1, characterized in that: The volume mass ratio of the deionized water solution containing ammonium chloride to the porous carbon material is 10 mL: 1-2 g; the volume mass ratio of the deionized water solution containing organic ammonium chloride to the porous carbon material is 10 mL: 1-2 g.

8. The method for preparing targeted autogenous acid for ultra-high temperature formations according to claim 1, characterized in that: The organic ammonium chloride includes one or more of benzyltrimethylammonium chloride, methyltriethylammonium chloride, methyltrioctylammonium chloride, and dimethyldiallylammonium chloride. The conditions for the first reaction are a reaction temperature of 25 to 35° C. and a reaction time of 5 to 8 hours.

9. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 1, characterized in that: The polyol includes any one of ethylene glycol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol. The concentration of the deionized water solution containing the polyol is 30 w / v% to 70 w / v%.

10. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 9, characterized in that: The concentration of the deionized water solution containing the polyol is 40 w / v% to 60 w / v%.

11. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 1, characterized in that: In step 2, the volume mass ratio of deionized water to the surface-modified porous carbon material is 20 mL:1-3 g; the conditions for the second reaction are a reaction temperature of 20-30° C. and a reaction time of 2-5 h.

12. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 1, characterized in that: In step 3, the oil phase is a continuous oil phase, and the continuous oil phase includes any one of white oil, diesel, kerosene, and gasoline; the emulsifier includes any one of Span60, Span80, N,N-dimethylhexanoyl ammonium, and diglycerol monolaurate; the volume mass ratio of the continuous oil phase to the emulsifier is 100 mL:3-10 g, and the dispersion conditions include: magnetic stirring, reaction temperature 20-30°C, and reaction time 0.5-1.5 h; the volume mass ratio of the continuous phase oil to epichlorohydrin is 100 mL:10-30 g, and the conditions for the third reaction are: reaction temperature 65-85°C, reaction time 3-5 h, and stirring speed 800-1200 r / min.

13. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 12, characterized in that: The volume mass ratio of the continuous oil phase to the emulsifier is 100mL:5~9g.

14. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 12, characterized in that: The volume mass ratio of the continuous phase oil to epichlorohydrin is 100 mL:15-20 g.

15. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 1, characterized in that: The carbonyl compound includes any one of paraformaldehyde, polyhexaldehyde, and polydimethylaminobenzaldehyde; the mass ratio of agent A to agent B is 3.5 to 8:

1.

16. The method for preparing targeted autogenous acid for use in ultra-high temperature formations according to claim 15, characterized in that: The mass ratio of agent A to agent B is 4 to 6:

1.

17. The targeted autogenous acid prepared by the method for preparing targeted autogenous acid for ultra-high temperature formations according to any one of claims 1 to 16, characterized in that: Targeted autogenous acid resistance to high temperature of 120-180℃, the acid concentration in 5 hours is greater than 0.1mol / L, and the acid concentration in 24 hours is greater than 2.9mol / L.

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