A carbon dioxide heavy oil extraction aid, its preparation method and application

Abstract

This invention provides a carbon dioxide heavy oil extraction aid, its preparation method, and its application. The carbon dioxide heavy oil extraction aid, based on 1 part by weight of alkyl polyoxypropylene polyoxyethylene ester, further comprises the following components: 0.1-10 parts by weight of alkylamine; 0.1-100 parts by weight of solvent; the general molecular formula of the alkyl polyoxypropylene polyoxyethylene ester is formula (I) or formula (II): In formula (I), R1 is a C1-C8 alkyl group; R2 is a C1-C8 alkyl group; a is an integer from 0 to 12; b is an integer from 1 to 12; In formula (II), R3 is a C1-C8 alkyl group; R4 is a C1-C8 alkyl group; c is an integer from 0 to 12; d is an integer from 1 to 12. The carbon dioxide heavy oil extraction aid prepared by this invention enhances the interaction between CO2 and heavy oil, improves the swelling effect of CO2 on heavy oil, and increases the mobilization capacity of heavy components, thereby reducing the precipitation of asphaltene and other substances, ultimately effectively improving oil recovery efficiency.

Description

Technical Field

[0001] This invention relates to the field of oilfield production, and more specifically, to a carbon dioxide heavy oil extraction aid, its preparation method, and its application. Background Technology

[0002] CCUS is a new development trend in CCS (Carbon Capture and Storage) technology. It involves purifying carbon dioxide emitted during production processes and then reusing it in new production processes, allowing for recycling rather than simple storage. Compared to CCS, CCUS can turn carbon dioxide into a resource, generating economic benefits and making it more practical. It can be divided into capture, transport, utilization, and storage stages. CO2 utilization refers to using the physical, chemical, or biological effects of CO2 to reduce CO2 emissions while simultaneously increasing energy production and efficiency, improving mineral resource extraction, converting and synthesizing chemicals, increasing the production and utilization of bio-agricultural products, and utilizing CO2 in consumer goods production. It is an emission reduction approach with incidental economic benefits.

[0003] Early research focused on the swelling and viscosity-reducing effects of CO2, as well as the reduction of oil-water interfacial tension. However, during CO2 oil recovery, especially in the cold recovery of heavy oil, CO2 dissolves in crude oil, which, while expanding and reducing viscosity, makes it easier to extract light components, while heavy components such as bitumen remain in the reservoir, ultimately leading to reservoir damage. Therefore, it is necessary to study a method to improve the efficiency of CO2 extraction of heavy oil, especially the utilization of bitumen. Summary of the Invention

[0004] To address the technical problems existing in the prior art, this invention provides a carbon dioxide heavy oil extraction aid, its preparation method, and its application.

[0005] This invention prepares alkyl polyoxypropylene polyoxyethylene ester. By introducing EO / PO fragments, the solubility of chemical agents in CO2 can be adjusted. The introduction of ester groups effectively enhances the interaction between CO2 and crude oil, thereby improving the swelling effect of CO2 on heavy oil.

[0006] This invention prepares a CO2 heavy oil extraction aid by compounding alkyl polyoxypropylene polyoxyethylene ester and alkylamine. This enhances the interaction between CO2 and heavy oil, improves the swelling effect of CO2 on heavy oil, and increases the mobilization capacity of heavy components, thereby reducing the precipitation of asphaltene and other substances, and ultimately effectively improving oil production efficiency.

[0007] One objective of this invention is to provide a carbon dioxide heavy oil extraction aid, comprising the following components in 1 part by weight of alkyl polyoxypropylene polyoxyethylene ester:

[0008] 1 part by weight of alkyl polyoxypropylene polyoxyethylene ester;

[0009] Alkylamine 0.1 to 10 parts by weight;

[0010] Solvent: 0.1–100 parts by weight;

[0011] The general molecular formula of the alkyl polyoxypropylene polyoxyethylene ester is formula (I) or formula (II):

[0012]

[0013] In equation (I), R 1 It is a C1 to C8 alkyl group; R 2 It is an alkyl group from C1 to C8; a is an integer from 0 to 12; b is an integer from 1 to 12;

[0014] In formula (II), R3 is a C1 to C8 alkyl group; R4 is a C1 to C8 alkyl group; c is an integer from 0 to 12; and d is an integer from 1 to 12.

[0015] In a preferred embodiment of the present invention,

[0016] Based on 1 part by weight of alkyl polyoxypropylene polyoxyethylene ester, it contains the following components:

[0017] 1 part by weight of alkyl polyoxypropylene polyoxyethylene ester;

[0018] Alkylamine 0.1 to 1 part by weight; for example, 0.1, 0.3, 0.5, 0.8, 1 part by weight or any two of the above values, such as 0.1 to 0.5 parts by weight;

[0019] Solvent 1 to 10 parts by weight.

[0020] In a preferred embodiment of the present invention,

[0021] The preparation method of the alkyl polyoxypropylene polyoxyethylene ester shown in formula (Ⅰ) includes:

[0022] Compound (III) is reacted with fatty acid A or fatty diacid A in the presence of acidic catalyst A to obtain compound (I);

[0023]

[0024] In formula (Ⅲ), R1 is an alkyl group from C1 to C8; a is an integer from 0 to 12; and b is an integer from 1 to 12.

[0025] In a preferred embodiment of the present invention,

[0026] The preparation method of the alkyl polyoxypropylene polyoxyethylene ester shown in formula (II) includes:

[0027] Compound (Ⅳ) is reacted with fatty acid B or fatty diacid B in the presence of acidic catalyst B to obtain compound (Ⅱ).

[0028]

[0029] In formula (Ⅳ), R3 is an alkyl group from C1 to C8; c is an integer from 0 to 12; and d is an integer from 1 to 12.

[0030] In a preferred embodiment of the present invention,

[0031] The fatty acid A is at least one of C1-C8 straight-chain or branched fatty acids; and / or,

[0032] The fatty diacid A is at least one of C1-C8 straight-chain or branched fatty diacids; and / or,

[0033] The acidic catalyst A is at least one of inorganic acids and organic acids, preferably at least one of inorganic acids, and more preferably sulfuric acid; and / or,

[0034] The reaction is carried out in solution; preferably, the solvent of the solution is at least one of toluene and chlorobenzene; and / or, the molar concentration of the total amount of reactants in the solution is 1 to 10 mol / L, more preferably 2 to 5 mol / L; and / or,

[0035] The molar ratio of the compound of formula (III), fatty acid A or fatty diacid A, and acidic catalyst A is 1:(0.25-1):(0.01-0.1); and / or,

[0036] The temperature of reaction one is 25–160°C, preferably 80–140°C; and / or,

[0037] The reaction time is 2 to 24 hours, preferably 8 to 16 hours.

[0038] In a preferred embodiment of the present invention,

[0039] The fatty acid B is at least one of C1-C8 straight-chain or branched fatty acids; and / or,

[0040] The fatty diacid B is at least one of C1-C8 straight-chain or branched fatty diacids; and / or,

[0041] The acidic catalyst B is at least one of inorganic acid and organic acid, preferably at least one of inorganic acid, and more preferably sulfuric acid; and / or,

[0042] The second reaction is carried out in solution; preferably, the solvent of the solution is at least one of toluene and chlorobenzene; and / or, the molar concentration of the total amount of reactants in the solution is 1–10 mol / L, more preferably 2–5 mol / L; and / or,

[0043] The molar ratio of the compound of formula (Ⅳ), fatty acid B or fatty diacid B, and acidic catalyst B is 1:(0.25-1):(0.01-0.1); and / or,

[0044] The temperature of reaction two is 25–160°C, preferably 80–160°C; and / or,

[0045] The reaction time for the second reaction is 2 to 24 hours, preferably 8 to 16 hours.

[0046] In a preferred embodiment of the present invention,

[0047] The alkylamine is at least one of the following straight-chain or branched amines with a C4-C18 carbon number: primary amine, secondary amine, tertiary amine; preferably, the alkylamine is at least one of the following straight-chain or branched amines with a total carbon number of 4-14: at least one of primary amine and secondary amine; and / or,

[0048] The solvent is at least one of C5-C20 straight-chain alkanes, toluene, and xylene, preferably at least one of C5-C16 straight-chain alkanes and xylene.

[0049] A second objective of this invention is to provide a method for preparing a carbon dioxide heavy oil extraction aid, comprising:

[0050] The carbon dioxide heavy oil extraction aid is obtained by mixing the components, including alkyl polyoxypropylene polyoxyethylene ester, alkylamine and solvent, in the stated weight proportions.

[0051] The third objective of this invention is to provide an application of a carbon dioxide heavy oil extraction aid in carbon dioxide flooding.

[0052] In a preferred embodiment of the present invention,

[0053] The carbon dioxide heavy oil extraction aid is injected in conjunction with or after being dissolved in carbon dioxide, with the injection amount being 0.01 to 5 wt% of the carbon dioxide content, preferably 0.1 to 5 wt%.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] This invention prepares a CO2 heavy oil extraction aid by compounding alkyl polyoxypropylene polyoxyethylene ester and alkylamine. This enhances the interaction between CO2 and heavy oil, improves the swelling effect of CO2 on heavy oil, and increases the mobilization capacity of heavy components, thereby reducing the precipitation of asphaltene and other substances, and ultimately effectively improving oil production efficiency.

[0056] The inventors believe that the above-mentioned technical effects are due to two main factors. Firstly, the alkyl polyoxypropylene polyoxyethylene ester in this invention can regulate the solubility of chemical agents in CO2 by introducing EO / PO fragments. Secondly, the introduction of ester groups and alkylamines effectively enhances the interaction between CO2 and crude oil, thereby improving the swelling effect of CO2 on heavy oil. Attached Figure Description

[0057] Figure 1 Phase experiment of CO2 with Shengli Oilfield GD3*526 crude oil (the upper phase is without chemical reagents, and the lower phase has 2% of composition 5 added). Detailed Implementation

[0058] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0059] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0060] Unless otherwise specified in the examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified were either readily available for purchase or prepared using methods disclosed in the prior art.

[0061] The raw materials used in the examples and comparative examples were all commercially available, and compounds 1A / 2A / 3A were custom-made alkyl polyoxyethylene polyoxypropylene ethers from Dorren.

[0062] Test method:

[0063] H-NMR spectrum: Bruker 400MHz;

[0064] Surfactant interfacial tension testing: The interfacial tension of CO2 / crude oil or CO2 / crude oil / chemical agent was determined by pendant drop method using a Teclis interfacial rheometer.

[0065] Phase state experiment: The phase state changes of CO2 wettability modifier / CO2 / crude oil were studied in a supercritical visible volume system using imaging methods.

[0066] Example 1

[0067] Under N2 protection at room temperature, compounds 1A (100 mmol) and 1B (100 mmol) were dissolved in 50 mL of toluene in a reaction vessel, followed by the slow addition of concentrated sulfuric acid (2 mmol). The temperature was then gradually increased to 140 °C, and the reaction was carried out for 8 h. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the filtrate. The filtrate was washed with NaOH water to neutralize it, extracted with petroleum ether, and the upper organic phase was collected and dried over anhydrous MgSO4 for 24 h. The solvent was removed by vacuum distillation to obtain compound 1C.

[0068] The structural formula of compound 1C is:

[0069] Where R1 is ethyl, R2 is ethyl, a is 0, and b is 1;

[0070] Test results: 1 ¹H NMR (400 MHz, CDCl₃, ppm): δ = 4.20–4.25 (m, 2H), 3.64–3.68 (m, 2H), 3.45–3.50 (m, 2H), 2.42–2.45 (m, 2H), 1.21–1.27 (m, 3H), 1.0–1.07 (m, 3H); The obtained compound 1C was confirmed.

[0071] Example 2

[0072] Under N2 protection at room temperature, compounds 2A (100 mmol) and 2B (100 mmol) were dissolved in 50 mL of toluene in a reaction vessel, followed by the slow addition of concentrated sulfuric acid (2 mmol). The temperature was then gradually increased to 120 °C, and the reaction was allowed to proceed for 16 h. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain the filtrate. The filtrate was washed with NaOH water to neutralize it, extracted with petroleum ether, and the upper organic phase was collected and dried over anhydrous MgSO4 for 24 h. The solvent was removed by vacuum distillation to obtain compound 2C.

[0073] The structural formula of compound 2C is:

[0074] Where R3 is n-butyl, R2 is ethyl, a is 1, and b is 4;

[0075] Test results: 1¹H NMR (400 MHz, CDCl₃, ppm): δ = 4.20–4.26 (m, 2H), 3.60–3.66 (m, 5H), 3.52–3.60 (m, 12H), 3.35–3.39 (m, 2H), 2.41–2.43 (m, 2H), 1.46–1.50 (m, 4H), 1.32–1.34 (m, 3H), 1.21–1.22 (m, 3H), 0.96–0.99 (m, 3H); The obtained compound 2C was confirmed.

[0076] Example 3

[0077] Under N2 protection at room temperature, compounds 3A (200 mmol) and 3B (100 mmol) were dissolved in 100 mL of chlorobenzene in a reaction vessel, followed by slow dropwise addition of concentrated sulfuric acid (4 mmol). The temperature was then gradually increased to 160 °C, and the reaction was allowed to proceed for 12 h. After the reaction was complete, the mixture was cooled to room temperature and filtered to obtain the filtrate. The filtrate was washed with NaOH water to neutralize it, extracted with petroleum ether, and the upper organic phase was collected and dried over anhydrous MgSO4 for 24 h. The solvent was removed by vacuum distillation to obtain compound 3C.

[0078] The structural formula of compound 3C is:

[0079] Where R3 is n-octyl, R4 is pentyl, c is 0, and d is 3;

[0080] Test results: 1 ¹H NMR (400MHz, CDCl₃, ppm): δ=4.21-4.26(m, 4H), 3.63-3.66(m, 4H), 3.52-3.55(m, 16H), 3.35-3.38(m, 4H), 2.32-2.34(m, 4H), 1.66-1.69(m, 4H), 1.42-1.50(m, 8H), 1.25-1.30(m, 18H), 0.88-0.91(m, 6H); The obtained compound 3C was confirmed.

[0081] Examples 1-3 used compounds as shown in Table 1:

[0082] Table 1. Structures of compounds in Examples 1-3

[0083]

[0084] The structural formulas of compounds 1A, 2A, and 3A are shown in formula (V);

[0085]

[0086] The structural formulas of compounds 1B and 2B are formula (VI):

[0087]

[0088] The structural formula of compound 3B is formula (VII):

[0089]

[0090] Examples 4-9

[0091] Preparation of CO2 oil recovery additives:

[0092] Compounds 1C, 2C, and 3C prepared in Examples 1 to 3 were combined with alkylamines and solvents according to the raw materials and mass fractions shown in Table 2. Examples are numbered 4 to 9, and carbon dioxide heavy oil extraction aids 1 to 6 were obtained respectively.

[0093] Table 2 Composition of CO2 Oil Enhancement Additives

[0094]

[0095] Comparative Examples 1-3

[0096] Preparation of CO2 oil recovery additives:

[0097] Compound 3C, alkylamine, and solvent prepared in Example 3 were formulated according to the raw materials and mass parts shown in Table 2. Examples are numbered Comparative Examples 1 to 3, respectively, to obtain carbon dioxide heavy oil extraction aid compositions 7 to 9.

[0098] Test Example 1: Surfactant Interfacial Tension Test

[0099] The interfacial tension between CO2 and Shengli Oilfield GD3*526 crude oil (5000 mPa.s, 50℃) under formation conditions (15 MPa, 95℃) was determined using a Teclis interfacial rheometer. The amount of the composition was 0.1% to 5% of the mass of CO2. The data are shown in Table 3.

[0100] Table 3 CO2 Oil Enhancement Additives: CO2 / Oil Interfacial Tension

[0101]

[0102] As shown in Table 3, the interfacial tension data indicates that the addition of the composition can reduce the interfacial tension between CO2 and crude oil, effectively helping CO2 utilize crude oil. Compared with composition 5, compositions 7-9 corresponding to comparative examples 1-3, due to the lack of components, are basically unable to reduce interfacial tension. In particular, the interfacial tension of comparative example 3, which lacks alkyl ester, actually increased, proving that there is a synergistic effect among the three components of the composition, and that the role of alkyl ester is the most important.

[0103] Test Example 2

[0104] CO2 crude oil phase:

[0105] The phase changes of CO2 and crude oil were observed using a high-temperature, high-pressure, variable-volume sight glass autoclave.

[0106] Experimental method: First, a certain amount of crude oil was injected into the reactor, and then CO2 was injected. By controlling the injection pressure, the mass ratio of crude oil to CO2 was kept constant. Then, by reducing the volume of the reactor, the pressure inside the reactor was continuously increased, and the two-phase changes of CO2 and crude oil were observed during the process.

[0107] Experimental conditions: Shengli Oilfield GD3*526 crude oil, temperature 40℃, CO2 to crude oil mass ratio 4:1.

[0108] The experimental results are shown in Figure 1 The pressure was increased to 15 MPa, and no significant swelling of the crude oil was observed throughout the process. After adding 2% of composition 5, the crude oil volume expanded by about 20% at 15 MPa and remained at that level for 180 minutes without any decline. This indicates that the addition of the chemical agent can help the crude oil swell under formation conditions, allowing it to flow out from the pores, preventing the precipitation of heavy components, and improving CO2 recovery efficiency.

[0109] By compounding the alkyl polyoxypropylene polyoxyethylene ester and alkylamine prepared in Examples 1-3, CO2 heavy oil extraction aids in Examples 4-9 were obtained. These aids enhanced the swelling effect of CO2 on heavy oil, improved the mobilization capacity of heavy components, reduced the precipitation of asphaltene and other substances, and ultimately effectively improved oil production efficiency.

Claims

1. A carbon dioxide heavy oil extraction aid, comprising, by weight 1 part alkyl polyoxypropylene polyoxyethylene ester, the following components: 1 part by weight of alkyl polyoxypropylene polyoxyethylene ester; Alkylamine 0.1 to 10 parts by weight; Solvent: 0.1–100 parts by weight; The general molecular formula of the alkyl polyoxypropylene polyoxyethylene ester is formula (I) or formula (II): In formula (I), R1 is a C1 to C8 alkyl group; R2 is a C1 to C8 alkyl group; a is an integer from 0 to 12; b is an integer from 1 to 12; In formula (II), R3 is a C1 to C8 alkyl group; R4 is a C1 to C8 alkyl group; c is an integer from 0 to 12; and d is an integer from 1 to 12.

2. The carbon dioxide heavy oil extraction aid as described in claim 1, characterized in that: Based on 1 part by weight of alkyl polyoxypropylene polyoxyethylene ester, it contains the following components: 1 part by weight of alkyl polyoxypropylene polyoxyethylene ester; Alkylamine 0.1 to 1 part by weight; Solvent 1 to 10 parts by weight.

3. The carbon dioxide heavy oil extraction aid as described in claim 1 or 2, characterized in that: The preparation method of the alkyl polyoxypropylene polyoxyethylene ester shown in formula (Ⅰ) includes: Compound (III) is reacted with fatty acid A or fatty diacid A in the presence of acidic catalyst A to obtain compound (I); In formula (Ⅲ), R1 is an alkyl group from C1 to C8; a is an integer from 0 to 12; and b is an integer from 1 to 12.

4. The carbon dioxide heavy oil extraction aid as described in claim 1 or 2, characterized in that: The preparation method of the alkyl polyoxypropylene polyoxyethylene ester shown in formula (II) includes: Compound (Ⅳ) is reacted with fatty acid B or fatty diacid B in the presence of acidic catalyst B to obtain compound (Ⅱ). In formula (Ⅳ), R3 is an alkyl group from C1 to C8; c is an integer from 0 to 12; and d is an integer from 1 to 12.

5. The carbon dioxide heavy oil extraction aid as described in claim 3, characterized in that: The fatty acid A is at least one of C1-C8 straight-chain or branched fatty acids; and / or, The fatty diacid A is at least one of C1-C8 straight-chain or branched fatty diacids; and / or, The acidic catalyst A is at least one of inorganic acids and organic acids, preferably at least one of inorganic acids, and more preferably sulfuric acid; and / or, The reaction is carried out in solution; preferably, the solvent of the solution is at least one of toluene and chlorobenzene; and / or, the molar concentration of the total amount of reactants in the solution is 1 to 10 mol / L, more preferably 2 to 5 mol / L; and / or, The molar ratio of the compound of formula (III), fatty acid A or fatty diacid A, and acidic catalyst A is 1:(0.25-1):(0.01-0.1); and / or, The temperature of reaction one is 25–160°C, preferably 80–140°C; and / or, The reaction time is 2 to 24 hours, preferably 8 to 16 hours.

6. The carbon dioxide heavy oil extraction aid as described in claim 4, characterized in that: The fatty acid B is at least one of C1-C8 straight-chain or branched fatty acids; and / or, The fatty diacid B is at least one of C1-C8 straight-chain or branched fatty diacids; and / or, The acidic catalyst B is at least one of inorganic acid and organic acid, preferably at least one of inorganic acid, and more preferably sulfuric acid; and / or, The second reaction is carried out in solution; preferably, the solvent of the solution is at least one of toluene and chlorobenzene; and / or, the molar concentration of the total amount of reactants in the solution is 1–10 mol / L, more preferably 2–5 mol / L; and / or, The molar ratio of the compound of formula (Ⅳ), fatty acid B or fatty diacid B, and acidic catalyst B is 1:(0.25-1):(0.01-0.1); and / or, The temperature of reaction two is 25–160°C, preferably 80–160°C; and / or, The reaction time for the second reaction is 2 to 24 hours, preferably 8 to 16 hours.

7. The carbon dioxide heavy oil extraction aid as described in claim 1, characterized in that: The alkylamine is at least one of the following straight-chain or branched amines with a C4-C18 carbon number: primary amine, secondary amine, tertiary amine; preferably, the alkylamine is at least one of the following straight-chain or branched amines with a total carbon number of 4-14: at least one of primary amine and secondary amine; and / or, The solvent is at least one of C5-C20 straight-chain alkanes, toluene, and xylene, preferably at least one of C5-C16 straight-chain alkanes and xylene.

8. A method for preparing a carbon dioxide heavy oil extraction aid as described in any one of claims 1 to 7, comprising: The carbon dioxide heavy oil extraction aid is obtained by mixing the components, including alkyl polyoxypropylene polyoxyethylene ester, alkylamine and solvent, in the stated weight proportions.

9. The application of a carbon dioxide heavy oil extraction aid as described in any one of claims 1 to 7 or a carbon dioxide heavy oil extraction aid obtained by the preparation method as described in claim 8 in carbon dioxide flooding.

10. The application as described in claim 9, characterized in that: The carbon dioxide heavy oil extraction aid is injected in conjunction with or dissolved in carbon dioxide, with the injection amount being 0.01 to 5 wt% of the carbon dioxide content.

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