Self-release acidizing and pressure-driving integrated agent as well as preparation method and application thereof

Abstract

The invention discloses a self-release acidizing pressure-driving integrated agent which has the following structural formula: # imgabs0 # w, x, y and z are all positive integers, and w + x + y + z = 20. The invention also discloses a preparation method of the self-release acidification pressure-driving integrated agent, which is characterized by comprising the following steps: (1) mixing titanium tetrachloride, Tween 80 and an organic solvent, adding the mixture into a reaction container, then adding a catalyst and an acid-binding agent into the reaction container, heating for reaction to obtain a reaction liquid, and extracting to obtain an ester exchange reaction product; and (2) uniformly mixing and stirring the compound emulsifier and water to obtain a mixed solvent, then adding a proper amount of the transesterification reaction product into the mixed solvent to form a reaction system, and then dispersing to obtain the self-release acidification pressure-flooding integrated agent.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas field exploitation, and in particular relates to a self-releasing acidizing pressure-drive integrated agent and a preparation method and application thereof. Background Art

[0002] With the continuous exploitation of heavy oil reservoirs, carbonate heavy oil reservoirs have become the focus of current reservoir development.

[0003] For carbonate heavy oil reservoirs, the most common treatment method is steam injection thermal recovery, but this process has serious problems in the development of medium-deep carbonate heavy oil reservoirs: high steam injection pressure, low bottom hole dryness, poor development effect or even inability to use. For example, Chinese patent application CN101139923A discloses a carbon dioxide-assisted steam drive method for developing deep heavy oil reservoirs. This method uses a combination of vertical wells and horizontal wells for steam drive to develop deep heavy oil reservoirs, and injects carbon dioxide gas while injecting steam. Although this method can improve the development effect of heavy oil reservoirs to a certain extent, it still cannot solve the outstanding problems in the development of medium-deep carbonate heavy oil reservoirs.

[0004] During the development of carbonate heavy oil reservoirs, another way to increase production is to first acidify the formation and then inject steam for thermal recovery. For example, Chinese invention patent application CN 104179488A discloses a method for improving the effect of developing low permeability carbonate heavy oil reservoirs. The method first injects high temperature resistant slow-speed steering acid into the formation to solve the difficulty of acidification of low permeability high temperature deep carbonate reservoirs. Then, carbon dioxide is injected into the reservoir. Carbon dioxide plays its multiple roles of reducing viscosity, reducing resistance, and increasing energy to improve the development efficiency of heavy oil. Finally, steam is injected into the reservoir for thermal recovery to further reduce the viscosity of heavy oil, increase crude oil fluidity, and improve the development effect of low permeability carbonate heavy oil reservoirs. Because this process can improve the permeability of carbonate rocks, it can effectively improve the mining effect of carbonate heavy oil reservoirs. However, during the acidification process, a large amount of acidic liquid needs to be transported to the formation through the equipment pipeline, which will cause serious corrosion to the equipment. In order to prevent the acidic liquid from corroding the equipment, an acid slow-release agent is usually added. However, this method requires the addition of a large amount of acid slow-release agent, which increases the application cost in disguise.

[0005] Therefore, developing a low-cost, simple and easy sustained-release acid has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] Purpose of the invention: In view of the deficiencies of the above-mentioned prior art, the present invention provides a self-releasing acidizing pressure-driven integrated agent and its preparation method and application. The pH of the self-releasing acidizing pressure-driven integrated agent is neutral at room temperature, and the damage to the equipment is small, so there is no need to add acid slow-release reagents. In addition, after the self-releasing acidizing pressure-driven integrated agent enters the carbonate heavy oil reservoir formation, it can decompose and release surfactants and acids under the high temperature environment of the formation. The acid produced by the decomposition can corrode the rock formation under the oil film, thereby playing a role in stripping the heavy oil, and the released surfactant can emulsify the heavy oil, which is beneficial to oil recovery.

[0007] Technical solution: A self-releasing acidification pressure-driven integrated agent, the structural formula of which is as follows:

[0008] in:

[0009] w, x, y, z are all positive integers, and w+x+y+z=20.

[0010] In order to avoid unnecessary misunderstanding, the above structural formula is explained - the repeating unit in the bracket of w (i.e. the bracket on the left) is the same as the repeating unit in the bracket corresponding to x, y, and z on the right, which is OCH2CH2.

[0011] A method for preparing the above-mentioned self-releasing acidifying pressure-driven integrated agent comprises the following steps:

[0012] (1) titanium tetrachloride, Tween 80 and a certain amount of organic solvent are mixed and added into a reaction container, and then a certain amount of catalyst and acid binding agent are added thereto, and the temperature is raised to 90-110° C. to react for at least 10 hours to obtain a reaction liquid, and then the reaction liquid is extracted to obtain an ester exchange reaction product;

[0013] (2) The compound emulsifier is mixed with a certain amount of water and stirred to obtain a mixed solvent, and then an appropriate amount of the ester exchange reaction product obtained in step (1) is added to the mixed solvent to form a reaction system, and then dispersed at 30-50° C. for at least 2 hours to obtain a self-releasing acidified pressure-driven integrated agent.

[0014] As a further improvement of the present invention, the organic solvent in step (1) is heptane.

[0015] Furthermore, in step (1), the amount of the organic solvent added is 50-60 wt % of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0016] As a further improvement of the present invention, in step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:(3-3.5), preferably 1:(3-3.1).

[0017] As a further improvement of the present invention, the catalyst in step (1) is silicon tetrachloride.

[0018] Furthermore, in step (1), the amount of the catalyst added is 0.2-0.7 wt % of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0019] As a further improvement of the present invention, the acid binding agent in step (1) is triethylamine.

[0020] Furthermore, in step (1), the molar ratio of the acid binding agent to titanium tetrachloride is (1-1.1):1, preferably (1-1.05):1.

[0021] Further, the extraction step in step (1) is as follows:

[0022] The reaction solution was distilled under reduced pressure to remove the organic solvent and unreacted titanium tetrachloride.

[0023] Then, the reaction solution after the reduced pressure distillation treatment is dissolved in a mixed solvent of toluene and water in an equal mass ratio, and the organic layer is extracted;

[0024] Then, the toluene is distilled off under reduced pressure to obtain the ester exchange reaction product.

[0025] As a further improvement of the present invention, the reaction system in step (2) is composed of water, a compound emulsifier and the ester exchange reaction product obtained in step (1). Based on the total mass of the reaction system, the water accounts for 60-70wt%, the compound emulsifier accounts for 10-15wt%, and the remainder is the ester exchange reaction product.

[0026] As a further improvement of the present invention, the compound emulsifier in step (2) is Span 80 and Tween 80, wherein:

[0027] The HLB value of the compound emulsifier is 9-12.

[0028] The use of the above-mentioned self-releasing acidizing and pressure-displacing integrated agent, or the self-releasing acidizing and pressure-displacing integrated agent prepared by any one of the above-mentioned preparation methods in the exploitation of carbonate heavy oil reservoirs.

[0029] Beneficial effects: The self-releasing acidification pressure-driven integrated agent disclosed in the present invention and its preparation method and application have the following advantages:

[0030] 1. Save mining costs - The pH of the self-releasing acidification pressure-driven integrated agent is neutral at room temperature, which causes little damage to the equipment. Therefore, there is no need to use or add acid slow-release reagents, which saves a certain amount of mining costs;

[0031] 2. After the self-releasing acidizing and pressure-displacing integrated agent is carried to the carbonate heavy oil reservoir formation, it can be decomposed to release surfactants and acids under the influence of the high temperature environment of the formation. The acid produced by the decomposition can corrode the rock formation under the oil film and effectively improve the permeability of the carbonate rock, thereby achieving the purpose of stripping the heavy oil. The surfactant produced by the decomposition can emulsify the heavy oil, thereby further improving the oil recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention discloses a flow chart of a method for preparing a self-releasing acidifying pressure-driven integrated agent. DETAILED DESCRIPTION

[0033] The specific embodiments of the present invention are described in detail below.

[0034] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0035] The self-releasing acidification pressure-driven integrated agent has the following structural formula:

[0036]

[0037] Wherein: w, x, y, z are all positive integers, and w+x+y+z=20.

[0038] In order to avoid unnecessary misunderstanding, the above structural formula is explained - the repeating unit in the bracket of w (i.e. the bracket on the left) is the same as the repeating unit in the bracket corresponding to x, y, and z on the right, which is OCH2CH2.

[0039] The preparation principle of the self-releasing acidifying pressure-driven integrated agent of the present invention is: using Tween 80 and titanium tetrachloride as raw materials, preparing the target product through an ester exchange reaction, the product is insoluble in water, but will hydrolyze in water. A stable emulsion is formed by dispersing in water with an emulsifier, and the hydrolysis rate is reduced by the protection of the emulsifier. After the self-releasing acidifying pressure-driven integrated agent is carried into the carbonate heavy oil formation, it is demulsified and hydrolyzed under the high temperature of the formation to produce Tween 80 and HCl. The decomposed HCl can corrode the rock formation under the oil film, thereby achieving the purpose of stripping the heavy oil, and the decomposed Tween 80 can emulsify the heavy oil, thereby improving the oil recovery efficiency. Its principle is realized through the following reaction:

[0040]

[0041] The present invention will be further described below with reference to specific embodiments and accompanying drawings:

[0042] Example 1

[0043] A self-releasing acidification pressure-driven integrated agent, the structural formula of which is as follows:

[0044] in:

[0045] w, x, y, z are all positive integers, and w=x=y=z=5.

[0046] Example 2

[0047] A self-releasing acidification pressure-driven integrated agent, the structural formula of which is as follows:

[0048] in:

[0049] w, x, y, z are all positive integers, and w=x=4, y=z=6.

[0050] Example 3

[0051] A self-releasing acidification pressure-driven integrated agent, the structural formula of which is as follows:

[0052] in:

[0053] w, x, y, z are all positive integers, and w=2, x=4, y=6, z=8.

[0054] Example 4

[0055] The preparation method of the self-releasing acidification pressure-driven integrated agent comprises the following steps:

[0056] (1) titanium tetrachloride, Tween 80 and a certain amount of organic solvent are mixed and added into a reaction container, and then a certain amount of catalyst and acid binding agent are added thereto, and the temperature is raised to 110° C. and reacted for 12 hours to obtain a reaction liquid, and then the reaction liquid is extracted to obtain an ester exchange reaction product;

[0057] (2) The compound emulsifier is mixed with a certain amount of water and stirred to obtain a mixed solvent, and then an appropriate amount of the ester exchange reaction product obtained in step (1) is added to the mixed solvent to form a reaction system, and then dispersed at 35° C. for 2 hours to obtain a self-releasing acidified pressure-driven integrated agent.

[0058] As a further improvement of the present invention, the organic solvent in step (1) is heptane.

[0059] Furthermore, in step (1), the amount of the organic solvent added is 50 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0060] As a further improvement of the present invention, in step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:3.

[0061] As a further improvement of the present invention, the catalyst in step (1) is silicon tetrachloride.

[0062] Furthermore, in step (1), the amount of the catalyst added is 0.7 wt % of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0063] As a further improvement of the present invention, the acid binding agent in step (1) is triethylamine.

[0064] Furthermore, in step (1), the molar ratio of the acid binding agent to titanium tetrachloride is 1:1.

[0065] Further, the extraction step in step (1) is as follows:

[0066] The reaction solution was distilled under reduced pressure to remove the organic solvent and unreacted titanium tetrachloride.

[0067] Then, the reaction solution after the reduced pressure distillation treatment is dissolved in a mixed solvent of toluene and water in an equal mass ratio, and the organic layer is extracted;

[0068] Then, the toluene is distilled off under reduced pressure to obtain the ester exchange reaction product.

[0069] As a further improvement of the present invention, the reaction system in step (2) is composed of water, a compound emulsifier and the ester exchange reaction product obtained in step (1). Based on the total mass of the reaction system, the water accounts for 60wt%, the compound emulsifier accounts for 10wt%, and the remainder (30wt%) is the ester exchange reaction product.

[0070] As a further improvement of the present invention, the compound emulsifier in step (2) is Span 80 and Tween 80, wherein:

[0071] The HLB value of the compound emulsifier is 9.

[0072] Application of the self-releasing acidizing and pressure-displacing integrated agent prepared by any one of the above preparation methods in the exploitation of carbonate heavy oil reservoirs.

[0073] Example 5

[0074] The preparation method of the self-releasing acidification pressure-driven integrated agent comprises the following steps:

[0075] (1) titanium tetrachloride, Tween 80 and a certain amount of organic solvent are mixed and added into a reaction container, and then a certain amount of catalyst and acid binding agent are added thereto, and the temperature is raised to 90° C. to react for 20 hours to obtain a reaction liquid, and then the reaction liquid is extracted to obtain an ester exchange reaction product;

[0076] (2) The compound emulsifier is mixed with a certain amount of water and stirred to obtain a mixed solvent, and then an appropriate amount of the ester exchange reaction product obtained in step (1) is added to the mixed solvent to form a reaction system, and then dispersed at 30° C. for 5 hours to obtain a self-releasing acidified pressure-driven integrated agent.

[0077] As a further improvement of the present invention, the organic solvent in step (1) is heptane.

[0078] Furthermore, in step (1), the amount of the organic solvent added is 50 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0079] As a further improvement of the present invention, in step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:3.

[0080] As a further improvement of the present invention, the catalyst in step (1) is silicon tetrachloride.

[0081] Furthermore, in step (1), the amount of the catalyst added is 0.2 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0082] As a further improvement of the present invention, the acid binding agent in step (1) is triethylamine.

[0083] Furthermore, in step (1), the molar ratio of the acid binding agent to titanium tetrachloride is 1:1.

[0084] Further, the extraction step in step (1) is as follows:

[0085] The reaction solution was distilled under reduced pressure to remove the organic solvent and unreacted titanium tetrachloride.

[0086] Then, the reaction solution after the reduced pressure distillation treatment is dissolved in a mixed solvent of toluene and water in an equal mass ratio, and the organic layer is extracted;

[0087] Then, the toluene is distilled off under reduced pressure to obtain the ester exchange reaction product.

[0088] As a further improvement of the present invention, the reaction system in step (2) is composed of water, a compound emulsifier and the ester exchange reaction product obtained in step (1). Based on the total mass of the reaction system, the water accounts for 60wt%, the compound emulsifier accounts for 10wt%, and the remainder is the ester exchange reaction product.

[0089] As a further improvement of the present invention, the compound emulsifier in step (2) is Span 80 and Tween 80, wherein:

[0090] The HLB value of the compound emulsifier is 9.

[0091] Application of the self-releasing acidizing and pressure-displacing integrated agent prepared by any one of the above preparation methods in the exploitation of carbonate heavy oil reservoirs.

[0092] Example 6

[0093] The preparation method of the self-releasing acidification pressure-driven integrated agent comprises the following steps:

[0094] (1) titanium tetrachloride, Tween 80 and a certain amount of organic solvent are mixed and added into a reaction container, and then a certain amount of catalyst and acid binding agent are added thereto, and the temperature is raised to 110° C. to react for 10 hours to obtain a reaction liquid, and then the reaction liquid is extracted to obtain an ester exchange reaction product;

[0095] (2) The compound emulsifier is mixed with a certain amount of water and stirred to obtain a mixed solvent, and then an appropriate amount of the ester exchange reaction product obtained in step (1) is added to the mixed solvent to form a reaction system, and then dispersed at 50° C. for 2 hours to obtain a self-releasing acidified pressure-driven integrated agent.

[0096] As a further improvement of the present invention, the organic solvent in step (1) is heptane.

[0097] Furthermore, in step (1), the amount of the organic solvent added is 60 wt % of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0098] As a further improvement of the present invention, in step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:3.5. In another embodiment, the molar ratio of Tween 80 to titanium tetrachloride is 1:3.1.

[0099] As a further improvement of the present invention, the catalyst in step (1) is silicon tetrachloride.

[0100] Furthermore, in step (1), the amount of the catalyst added is 0.7 wt % of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0101] As a further improvement of the present invention, the acid binding agent in step (1) is triethylamine.

[0102] Furthermore, in step (1), the molar ratio of the acid binding agent to titanium tetrachloride is 1.1: 1. In another embodiment, the molar ratio of the acid binding agent to titanium tetrachloride in step (1) is 1.05:1.

[0103] Further, the extraction step in step (1) is as follows:

[0104] The reaction solution was distilled under reduced pressure to remove the organic solvent and unreacted titanium tetrachloride.

[0105] Then, the reaction solution after the reduced pressure distillation treatment is dissolved in a mixed solvent of toluene and water in an equal mass ratio, and the organic layer is extracted;

[0106] Then, the toluene is distilled off under reduced pressure to obtain the ester exchange reaction product.

[0107] As a further improvement of the present invention, the reaction system in step (2) is composed of water, a compound emulsifier and the ester exchange reaction product obtained in step (1). Based on the total mass of the reaction system, the water accounts for 70wt%, the compound emulsifier accounts for 15wt%, and the remainder is the ester exchange reaction product.

[0108] As a further improvement of the present invention, the compound emulsifier in step (2) is Span 80 and Tween 80, wherein:

[0109] The HLB value of the compound emulsifier is 12.

[0110] Application of the self-releasing acidizing and pressure-displacing integrated agent prepared by any one of the above preparation methods in the exploitation of carbonate heavy oil reservoirs.

[0111] Example 7

[0112] The preparation method of the self-releasing acidification pressure-driven integrated agent comprises the following steps:

[0113] (1) titanium tetrachloride, Tween 80 and a certain amount of organic solvent are mixed and added into a reaction container, and then a certain amount of catalyst and acid binding agent are added thereto, and the temperature is raised to 100° C. and reacted for 15 hours to obtain a reaction liquid, and then the reaction liquid is extracted to obtain an ester exchange reaction product;

[0114] (2) The compound emulsifier is mixed with a certain amount of water and stirred to obtain a mixed solvent, and then an appropriate amount of the ester exchange reaction product obtained in step (1) is added to the mixed solvent to form a reaction system, and then dispersed at 40° C. for 3 hours to obtain a self-releasing acidified pressure-driven integrated agent.

[0115] As a further improvement of the present invention, the organic solvent in step (1) is heptane.

[0116] Furthermore, in step (1), the amount of the organic solvent added is 55 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0117] As a further improvement of the present invention, in step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:3.2. In another embodiment, in step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:3.05.

[0118] As a further improvement of the present invention, the catalyst in step (1) is silicon tetrachloride.

[0119] Furthermore, in step (1), the amount of the catalyst added is 0.5 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0120] As a further improvement of the present invention, the acid binding agent in step (1) is triethylamine.

[0121] Furthermore, in step (1), the molar ratio of the acid binding agent to titanium tetrachloride is 1.06: 1. In another embodiment, the molar ratio of the acid binding agent to titanium tetrachloride in step (1) is 1.03:1.

[0122] Further, the extraction step in step (1) is as follows:

[0123] The reaction solution was distilled under reduced pressure to remove the organic solvent and unreacted titanium tetrachloride.

[0124] Then, the reaction solution after the reduced pressure distillation treatment is dissolved in a mixed solvent of toluene and water in an equal mass ratio, and the organic layer is extracted;

[0125] Then, the toluene is distilled off under reduced pressure to obtain the ester exchange reaction product.

[0126] As a further improvement of the present invention, the reaction system in step (2) is composed of water, a compound emulsifier and the ester exchange reaction product obtained in step (1). Based on the total mass of the reaction system, the water accounts for 65wt%, the compound emulsifier accounts for 12wt%, and the remainder is the ester exchange reaction product.

[0127] As a further improvement of the present invention, the compound emulsifier in step (2) is Span 80 and Tween 80, wherein:

[0128] The HLB value of the compound emulsifier is 10.

[0129] Application of the self-releasing acidizing and pressure-displacing integrated agent prepared by any one of the above preparation methods in the exploitation of carbonate heavy oil reservoirs.

[0130] Example 8

[0131] The preparation method of the self-releasing acidification pressure-driven integrated agent comprises the following steps:

[0132] (1) titanium tetrachloride, Tween 80 and a certain amount of organic solvent are mixed and added into a reaction container, and then a certain amount of catalyst and acid binding agent are added thereto, and the temperature is raised to 95° C. and reacted for 13 hours to obtain a reaction liquid, and then the reaction liquid is extracted to obtain an ester exchange reaction product;

[0133] (2) The compound emulsifier is mixed with a certain amount of water and stirred to obtain a mixed solvent, and then an appropriate amount of the ester exchange reaction product obtained in step (1) is added to the mixed solvent to form a reaction system, and then dispersed at 45° C. for 3 hours to obtain a self-releasing acidified pressure-driven integrated agent.

[0134] As a further improvement of the present invention, the organic solvent in step (1) is heptane.

[0135] Furthermore, in step (1), the amount of the organic solvent added is 52 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0136] As a further improvement of the present invention, in step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:3.05.

[0137] As a further improvement of the present invention, the catalyst in step (1) is silicon tetrachloride.

[0138] Furthermore, in step (1), the amount of the catalyst added is 0.35 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0139] As a further improvement of the present invention, the acid binding agent in step (1) is triethylamine.

[0140] Furthermore, in step (1), the molar ratio of the acid binding agent to titanium tetrachloride is 1.05:1.

[0141] Further, the extraction step in step (1) is as follows:

[0142] The reaction solution was distilled under reduced pressure to remove the organic solvent and unreacted titanium tetrachloride.

[0143] Then, the reaction solution after the reduced pressure distillation treatment is dissolved in a mixed solvent of toluene and water in an equal mass ratio, and the organic layer is extracted;

[0144] Then, the toluene is distilled off under reduced pressure to obtain the ester exchange reaction product.

[0145] As a further improvement of the present invention, the reaction system in step (2) is composed of water, a compound emulsifier and the ester exchange reaction product obtained in step (1). Based on the total mass of the reaction system, the water accounts for 60wt%, the compound emulsifier accounts for 15wt%, and the remainder is the ester exchange reaction product.

[0146] As a further improvement of the present invention, the compound emulsifier in step (2) is Span 80 and Tween 80, wherein:

[0147] The HLB value of the compound emulsifier is 11.

[0148] Application of the self-releasing acidizing and pressure-displacing integrated agent prepared by any one of the above preparation methods in the exploitation of carbonate heavy oil reservoirs.

[0149] Example 9

[0150] The preparation method of the self-releasing acidification pressure-driven integrated agent comprises the following steps:

[0151] (1) titanium tetrachloride, Tween 80 and a certain amount of organic solvent are mixed and added into a reaction container, and then a certain amount of catalyst and acid binding agent are added thereto, and the temperature is raised to 105° C. and reacted for 11 hours to obtain a reaction liquid, and then the reaction liquid is extracted to obtain an ester exchange reaction product;

[0152] (2) The compound emulsifier is mixed with a certain amount of water and stirred to obtain a mixed solvent, and then an appropriate amount of the ester exchange reaction product obtained in step (1) is added to the mixed solvent to form a reaction system, and then dispersed at 45° C. for 3 hours to obtain a self-releasing acidified pressure-driven integrated agent.

[0153] As a further improvement of the present invention, the organic solvent in step (1) is heptane.

[0154] Furthermore, in step (1), the amount of the organic solvent added is 58 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0155] As a further improvement of the present invention, in step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:3.1.

[0156] As a further improvement of the present invention, the catalyst in step (1) is silicon tetrachloride.

[0157] Furthermore, in step (1), the amount of the catalyst added is 0.5 wt% of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

[0158] As a further improvement of the present invention, the acid binding agent in step (1) is triethylamine.

[0159] Furthermore, in step (1), the molar ratio of the acid binding agent to titanium tetrachloride is 1.05:1.

[0160] Further, the extraction step in step (1) is as follows:

[0161] The reaction solution was distilled under reduced pressure to remove the organic solvent and unreacted titanium tetrachloride.

[0162] Then, the reaction solution after the reduced pressure distillation treatment is dissolved in a mixed solvent of toluene and water in an equal mass ratio, and the organic layer is extracted;

[0163] Then, the toluene is distilled off under reduced pressure to obtain the ester exchange reaction product.

[0164] As a further improvement of the present invention, the reaction system in step (2) is composed of water, a compound emulsifier and the ester exchange reaction product obtained in step (1). Based on the total mass of the reaction system, the water accounts for 70wt%, the compound emulsifier accounts for 10wt%, and the remainder is the ester exchange reaction product.

[0165] As a further improvement of the present invention, the compound emulsifier in step (2) is Span 80 and Tween 80, wherein:

[0166] The HLB value of the compound emulsifier is 9.

[0167] Application of the self-releasing acidizing and pressure-displacing integrated agent prepared by any one of the above preparation methods in the exploitation of carbonate heavy oil reservoirs.

[0168] Performance characterization:

[0169] 1. Hydrogen ion release capacity

[0170] In order to characterize the acid releasing performance of a self-releasing acidifying pressure-driven integrated agent as the temperature changes, the self-releasing acidifying pressure-driven integrated agent synthesized in Example 4 is placed in a three-necked bottle, the temperature is increased, the content of hydrogen ions in the acid-base titration test system is compared with the theoretical amount of completely released hydrogen ions, and the release percentage is tested. From the test results, it can be seen that the self-releasing acidifying pressure-driven integrated agent continuously releases hydrogen ions as the temperature increases, and the amount of hydrogen ions released is relatively large at temperatures above 120°C.

[0171] 2. Oil displacement effect

[0172] In order to characterize the oil displacement effect of a self-releasing acidizing and pressure-displacing integrated agent, the carbonate formation conditions were simulated and the self-releasing acidizing and pressure-displacing integrated agent synthesized in Example 4-9 was subjected to oil displacement experiments. The results are shown in the table.

[0173] Table 1 Oil displacement effect

[0174] Group Normal harvest (%) Final harvest (%) Improved recovery (%) Example 4 47.3 54.7 7.4 Example 5 47％ 54 7 Example 6 46.5 53 6.5 Example 7 48 54.5 6.5 Example 8 46 52.3 6.3 Example 9 43 49.8 6.8

[0175] It can be seen from Table 1 that the self-releasing acidizing and pressure-flooding integrated agent can significantly improve the recovery factor.

[0176] The above describes the embodiments of the present invention in detail. However, the present invention is not limited to the above embodiments, and various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A self-releasing acidification pressure-driven integrated agent, characterized in that: Its structural formula is as follows: in: w, x, y, z are all positive integers, and w+x+y+z=20.

2. A method for preparing the self-releasing acidifying pressure-driven integrated agent according to claim 1, characterized in that: The following steps are involved: (1) titanium tetrachloride, Tween 80 and a certain amount of organic solvent are mixed and added into a reaction container, and then a certain amount of catalyst and acid binding agent are added thereto, and the temperature is raised to 90-110° C. to react for at least 10 hours to obtain a reaction liquid, and then the reaction liquid is extracted to obtain an ester exchange reaction product; (2) The compound emulsifier is mixed with a certain amount of water and stirred to obtain a mixed solvent, and then an appropriate amount of the ester exchange reaction product obtained in step (1) is added to the mixed solvent to form a reaction system, and then dispersed at 30-50° C. for at least 2 hours to obtain a self-releasing acidified pressure-driven integrated agent.

3. The method for preparing a self-releasing acidifying pressure-driven integrated agent according to claim 2, characterized in that: The organic solvent in step (1) is heptane.

4. The method for preparing a self-releasing acidifying pressure-driven integrated agent according to claim 2, characterized in that: In step (1), the amount of the organic solvent added is 50-60 wt % of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

5. The method for preparing a self-releasing acidifying pressure-driven integrated agent according to claim 2, characterized in that: In step (1), the molar ratio of Tween 80 to titanium tetrachloride is 1:(3-3.5), preferably 1:(3-3.1).

6. The method for preparing a self-releasing acidifying pressure-driven integrated agent according to claim 2, characterized in that: The catalyst in step (1) is silicon tetrachloride.

7. The method for preparing a self-releasing acidifying pressure-driven integrated agent according to claim 2, characterized in that: In step (1), the added amount of the catalyst is 0.2-0.7 wt % of the sum of the mass of titanium tetrachloride, Tween 80 and the acid binding agent.

8. The method for preparing a self-releasing acidifying pressure-driven integrated agent according to claim 2, characterized in that: The acid binding agent in step (1) is triethylamine.

9. The method for preparing a self-releasing acidifying pressure-driven integrated agent according to claim 2, characterized in that: The molar ratio of the acid binding agent to titanium tetrachloride in step (1) is (1-1.1):1, preferably (1-1.05):

1.

10. The method for preparing a self-releasing acidification pressure-driven integrated agent according to claim 2, characterized in that: The extraction steps in step (1) are as follows: The reaction solution was distilled under reduced pressure to remove the organic solvent and unreacted titanium tetrachloride. Then, the reaction solution after the reduced pressure distillation treatment is dissolved in a mixed solvent of toluene and water in an equal mass ratio, and the organic layer is extracted; Then, the toluene is distilled off under reduced pressure to obtain the ester exchange reaction product.

11. The method for preparing a self-releasing acidifying pressure-driven integrated agent according to claim 2, characterized in that: The reaction system in step (2) is composed of water, a compound emulsifier and the ester exchange reaction product obtained in step (1). Based on the total mass of the reaction system, the water accounts for 60-70wt%, the compound emulsifier accounts for 10-15wt%, and the remainder is the ester exchange reaction product.

12. The method for preparing a self-releasing acidification pressure-driven integrated agent according to claim 2, characterized in that: The compound emulsifier in step (2) is Span 80 and Tween 80, wherein: The HLB value of the compound emulsifier is 9-12.

13. Use of the self-releasing acidizing and pressure-displacing integrated agent according to claim 1 or the self-releasing acidizing and pressure-displacing integrated agent prepared by the preparation method according to any one of claims 2 to 12 in the exploitation of carbonate heavy oil reservoirs.

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