Carbon dioxide viscosity enhancer, method for preparing the same, and use thereof

Abstract

This invention discloses a carbon dioxide viscosity enhancer, its preparation method, and its application. The carbon dioxide viscosity enhancer comprises an amino compound and a second compound, wherein the second compound is at least one of the following compounds: an ether-containing compound and an ester-containing compound. After the addition of the carbon dioxide viscosity enhancer, the viscosity increases by more than 10 times compared to pure carbon dioxide, thereby effectively increasing the carbon dioxide sweep efficiency and improving oil recovery.

Description

Technical Field

[0001] This invention relates to the field of enhanced oil recovery technology, specifically to a carbon dioxide viscosity enhancer, its preparation method, and its application. Background Technology

[0002] Injecting recovered CO2 into oil and gas reservoirs to enhance oil recovery not only allows for long-term CO2 storage to fulfill emission reduction obligations but also improves recovery rates for greater economic benefits, successfully transforming what was once a "hazard in the air" into a "treasure underground." However, a serious technical challenge exists in CO2 displacement: the large viscosity contrast between underground crude oil and injected CO2 leads to an unfavorable mobility ratio, causing early CO2 breakthrough, reduced reservoir sweep efficiency, and decreased oil production.

[0003] Therefore, to achieve good CO2-driven oil recovery, it is essential to control gas channeling, adjust the injection profile, and expand the gas sweep area to maximize CO2 contact with remaining oil, thereby improving oil washing efficiency and ultimately achieving cost-effective and efficient enhanced oil recovery. The development of viscosity enhancers dissolved in CO2 to increase the viscosity of the mobile phase CO2 for mobility control has attracted considerable attention.

[0004] Due to the low dielectric constant ε (1.0–1.6) and unit oxidative efficiency α / v of supercritical CO2, it is a very weak solvent for most non-volatile solutes. Therefore, the low solubility of polymers in CO2 prevents them from effectively thickening. For example, polyvinyl acetate (PVAc) is a polymer with a relatively high affinity for CO2 and can interact with multiple CO2 molecular sites. Even so, dissolving 5 wt% of PVAc with a degree of polymerization of 8000 at room temperature requires a pressure as high as 75 MPa, resulting in a negligible thickening effect. Furthermore, the use of large amounts of co-solvents (toluene or others, 10–50%) significantly increases costs.

[0005] Therefore, there is an urgent need for a thickener that can effectively increase the viscosity of carbon dioxide. Summary of the Invention

[0006] To address the problem of low viscosity of carbon dioxide in existing technologies, which leads to easy cross-flow during oil displacement, this invention provides a carbon dioxide viscosity enhancer, its preparation method, and its application. The viscosity enhancer, when added, increases the viscosity of carbon dioxide by more than 10 times compared to pure carbon dioxide, thereby expanding the carbon dioxide sweep efficiency and improving oil recovery.

[0007] One objective of this invention is to provide a carbon dioxide thickener comprising an amino compound and a second compound, wherein the second compound is at least one of the following compounds: an ether-containing compound and an ester-containing compound.

[0008] In a preferred embodiment of the present invention,

[0009] The amine compound is at least one of compounds containing an amine group structure of a primary amine and / or a secondary amine. Preferably, the portion of the amine compound linked to the amine group is at least one of a fluoropolyacrylate group, a polysiloxane group, a long-chain hydrocarbon group, and a fluoroalkyl group, preferably at least one of a fluoropolyacrylate group and a polysiloxane group; and / or,

[0010] The second compound contains at least two ether bonds and two ester bonds in total.

[0011] In a preferred embodiment of the present invention,

[0012] When the portion attached to the amine group is a fluoropolyacrylate group, the structure of the amine compound is shown in formula (I):

[0013]

[0014] Wherein, R1 is one of -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, and -C3H6OH; R3 is C4-C 12 Fluorinated alkyl groups, preferably C8-C 12 The fluoroalkyl group is more preferably perfluorohexylethyl; and the ratio of H to F in R3 is (0-0.5):1; R4 is -H or -CH3, and R5 is a C1-C5 alkylene or carbonyl group; m:n = 1:(0.1-1), preferably m:n = 1:(0.1-0.3); when the part connected to the amine group is a fluoropolyacrylate group, the number average molecular weight of the amine compound is 1000-10000, preferably 4000-7000. m represents a structural unit. The average degree of polymerization, where n represents the structural unit. The average degree of polymerization; in equation (I), the structural unit With structural units Random arrangement.

[0015] When the portion attached to the amine group is a fluoropolyacrylate group, the amine compound can be obtained commercially or prepared by any method disclosed in the art in the prior art.

[0016] In a preferred embodiment of the present invention,

[0017] When the portion attached to the amine group is a polysiloxane, the structure of the amine compound is shown in formula (II):

[0018]

[0019] Wherein, R1 is one of -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, and -C3H6OH; R6 is a C1-C5 alkylene or ester group; p:q = 1:(0.1-0.5), preferably p:q = 1:(0.1-0.3); when the part connected to the amine group is a polysiloxane alkyl group, the number average molecular weight of the amine compound is 1000-20000, preferably 6000-10000. p represents a structural unit. The average degree of polymerization, q represents the structural unit. The average degree of polymerization; in equation (II), the structural unit With structural units Random arrangement.

[0020] When the part connected to the amine group is a polysiloxane, the amine compound can be obtained commercially or prepared by any method disclosed in the art in the prior art, preferably by the method described in the reference "Li Mingtao, An Qiufeng, Hu Liangwei. Synthesis, characterization and application performance of N-cyclohexyl-γ-aminopropyl polydimethylsiloxane [J]. Fine Chemicals, 2006, 23(4):4. DOI:10.3321 / j.issn:1003-5214.2006.04.022."

[0021] In a preferred embodiment of the present invention,

[0022] When the part attached to the amine group is a long-chain hydrocarbon group, the structure of the amine compound is shown in formula (III):

[0023] R7NHR1 formula (III);

[0024] Among them, R7 is C 10 -C 24 The aliphatic hydrocarbon group, preferably C 10 -C 20 The aliphatic hydrocarbon group; R1 is one of -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, and -C3H6OH.

[0025] When the part attached to the amine group is a long-chain hydrocarbon group, the amine compound can be obtained commercially or prepared by any method disclosed in the art in the prior art.

[0026] In this invention, unless otherwise defined, aliphatic hydrocarbon groups refer to aliphatic alkyl and alkenyl groups, particularly straight-chain or branched alkyl and alkenyl groups. The number of carbon atoms in the aliphatic hydrocarbon group can be 10-24, for example, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24.

[0027] In a preferred embodiment of the present invention,

[0028] When the portion attached to the amino group is a fluoroalkyl group, the structure of the amino compound is shown in formula (Ⅳ):

[0029] R8NHR1 (Ⅳ);

[0030] R8 is a perfluorinated or partially fluorinated C6-C. 24 Alkyl groups, preferably perfluorinated or partially fluorinated C6-C 20 Alkyl group, wherein the ratio of H to F in R8 is less than or equal to 1:1; R1 is one of -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, and -C3H6OH.

[0031] When the portion attached to the amino group is a fluoroalkyl group, the amino compound can be obtained commercially or prepared by any method disclosed in the art in the prior art.

[0032] In a preferred embodiment of the present invention,

[0033] The ether-containing compound is at least one of the compounds shown in formula (V):

[0034] And / or,

[0035] The ester-containing compound is at least one of the compounds shown in formula (VI):

[0036]

[0037] In equations (V) and (VI) above, R9 and R 10 Each is independently a C1-C6 alkyl or aryl group; R 9 and R 10 Each of R1 and R2 is independently a C1-C6 alkyl or aryl group; each of R2 is independently a C1-C3 alkylene group, a substituted C1-C3 alkylene group, or a -R group. 11 OR 12 -, where R 11 and R 12Each of the substituents is independently a C1-C6 alkyl or aryl group; preferably, the substituents in the substituted C1-C3 alkylene group are C1-C6 alkyl or aryl groups or C1-C6 alkyl or aryl substituted ester groups.

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

[0039] The second compound is selected from at least one of the compounds shown in formula (VI).

[0040] In a preferred embodiment of the present invention,

[0041] The molar ratio of the amino compound to the second compound is 1:(0.5-10), preferably 1:(0.5-6).

[0042] A second objective of this invention is to provide a method for preparing a carbon dioxide thickener, which is one of the objectives of this invention, comprising the step of thoroughly mixing components including the amine compound and the second compound.

[0043] In a preferred embodiment of the present invention,

[0044] The conditions for thorough mixing include mixing for 1-120 minutes at a stirring speed of 50-1000 rpm.

[0045] A third objective of this invention is to provide a method for increasing the viscosity of carbon dioxide, comprising mixing carbon dioxide with a carbon dioxide thickener obtained by one objective of this invention or by the preparation method of another objective of this invention; preferably, the method comprises the steps of alternately or jointly injecting the carbon dioxide thickener and carbon dioxide, or mixing it with carbon dioxide first and then injecting it into a porous medium containing crude oil; more preferably, the carbon dioxide is supercritical and / or liquid carbon dioxide.

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

[0047] The hydrogen group in the amine compound associates with the oxygen group in the second compound to form an associative compound in carbon dioxide.

[0048] The amino compound and the second compound associate in carbon dioxide to form the following structure:

[0049]

[0050] Wherein, R1 is independently -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, or -C3H6OH; R2 is a C1-C3 alkylene group, a substituted C1-C3 alkylene group, or -R 11 OR 12-, where R 11 and R 12 Each is independently a C1-C6 alkyl or aryl group; preferably, the substituents in the substituted C1-C3 alkylene groups are C1-C6 alkyl or aryl groups or C1-C6 alkyl or aryl substituted ester groups; It represents the portion of an amino compound that is attached to an amino group; This represents the portion of the second compound that is connected to -O-.

[0051] In a preferred embodiment of the present invention,

[0052] The volume ratio of the carbon dioxide thickener to carbon dioxide is (0.1-5):100, preferably (0.3-3):100.

[0053] The present invention can adopt the following specific technical solutions:

[0054] The method for increasing carbon dioxide viscosity includes injecting the carbon dioxide viscosity enhancer alternately or together with carbon dioxide, or mixing it with carbon dioxide before injecting it into a porous medium containing crude oil, thereby increasing the viscosity of carbon dioxide, expanding the sweep efficiency of carbon dioxide, and thus improving the recovery rate.

[0055] The fourth objective of this invention is to provide an application of a carbon dioxide thickener obtained by one of the objectives of this invention or a carbon dioxide thickener obtained by the preparation method of another objective of this invention in improving the viscosity of carbon dioxide.

[0056] This invention has the following advantages:

[0057] The amine groups in the amine compounds of this invention are primary and secondary amines. The hydrogen atoms in these amines can interact with the oxygen atoms in the ester or ether bonds through intermolecular hydrogen bonding, causing the two molecules to associate. The portion attached to the amine group has a strong affinity for carbon dioxide, promoting its dissolution in carbon dioxide. By controlling the molecular weight and the ratio of the two groups, they can associate into larger aggregates in supercritical or liquid carbon dioxide, restricting the movement of carbon dioxide and thus increasing its viscosity. Detailed Implementation

[0058] The present invention will now be described in detail with reference to specific 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] In this embodiment of the invention, except for the raw materials whose synthesis methods are already noted, all other raw materials used are conventionally available commercial raw materials. In this embodiment of the invention, the number-average molecular weight of the amine compound is determined by gel permeation chromatography, and the average degree of polymerization of each structural unit in the amine compound is obtained by proton NMR spectroscopy.

[0060] Example 1

[0061] Preparation of aminosiloxanes:

[0062] In a 500 mL three-necked flask equipped with a stirrer, thermometer, and reflux condenser, 120 g of octamethylcyclotetrasiloxane, 2 g of hexamethyldisiloxane, 21 g of 3-aminopropylmethyldimethoxysilane, and 0.2 g of tetramethylammonium hydroxide catalyst were added sequentially. The mixture was purged with nitrogen, stirred until homogeneous, heated to 120 °C, and reacted for 4 hours, then equilibrated at 135 °C for 2 hours. The product was then evacuated under reduced pressure for 30 minutes and cooled to room temperature to obtain a transparent, viscous liquid, namely aminosiloxane (poly[dimethylsiloxane-co-(3-aminopropyl)methylsiloxane).

[0063] The structure of aminosiloxane (poly[dimethylsiloxane-co-(3-aminopropyl)methylsiloxane]) is as follows:

[0064] Where R1 is H, and R6 = -C3H6-; the chemical shifts (δ) obtained by 1H NMR spectroscopy (using deuterated chloroform as solvent) from high field to low field are as follows: δ H1 0.02 (methyl hydrogen atom on siloxane), δ H2 0.45 (methylene hydrogen atom on siloxane), δ H3 1.42 (hydrogen atom of the methylene group at the nitrogen atom) and δ H4 2.60 (hydrogen atoms of the methylene group bonded to the nitrogen atom), by integrating the above hydrogen atoms, p:q = 3.5:1; its number-average molecular weight Mn = 8724 was determined by GPC.

[0065] Preparation of carbon dioxide thickener:

[0066] The above-mentioned aminosiloxane (poly[dimethylsiloxane-co-(3-aminopropyl)methylsiloxane]) and triglyceride were mixed at a molar ratio of 1:5 and stirred at 300 rpm for 30 min to obtain a carbon dioxide thickener.

[0067] First, supercritical carbon dioxide was injected into a 1 / 16-inch stainless steel capillary tube at a rate of 5 mL / min, with the temperature controlled at 40°C and the back pressure at 40 MPa. The pressure difference ΔP0 between the front and rear ends at injection equilibrium was measured and recorded using a differential pressure gauge. Then, the aforementioned carbon dioxide thickener was injected together with supercritical carbon dioxide into the same 1 / 16-inch stainless steel capillary tube at a rate of 4.9 mL / min for supercritical carbon dioxide and 0.10 mL / min for the carbon dioxide thickener, with the temperature controlled at 40°C and the back pressure at 40 MPa. The pressure difference ΔP1 between the front and rear ends at injection equilibrium was measured and recorded using a differential pressure gauge.

[0068] Calculate the viscosity increase factor R of supercritical carbon dioxide based on the above pressure difference.

[0069] R = ΔP1 / ΔP0

[0070] The experimental results showed that ΔP0 = 1.8, ΔP1 = 28.9, and R = 16.1.

[0071] After adding carbon dioxide thickener, the viscosity of supercritical carbon dioxide increased by 16.1 times.

[0072] Comparative Example 1

[0073] The aminosiloxane obtained in Example 1 above was injected together with supercritical carbon dioxide into a 1 / 16-inch stainless steel capillary tube. The supercritical carbon dioxide injection rate was 4.9 mL / min, and the aminosiloxane injection rate was 0.10 mL / min. The temperature was controlled at 40°C, and the back pressure was 40 MPa. The pressure difference ΔP between the front and rear ends at the injection equilibrium was measured and recorded using a differential pressure gauge. 1-1 .

[0074] The above-mentioned tripropionate and supercritical carbon dioxide were injected together into a 1 / 16-inch stainless steel capillary tube. The supercritical carbon dioxide injection rate was 4.9 mL / min, and the tripropionate injection rate was 0.10 mL / min. The temperature was controlled at 40℃, and the back pressure was 40 MPa. The pressure difference ΔP between the front and rear ends at injection equilibrium was measured and recorded using a differential pressure gauge. 1-2 .

[0075] The experimental results show that: ΔP 1-1 =5.5, ΔP 1-1 =2.0,

[0076] The calculation process was the same as in Example 1. After adding aminosiloxane and triglyceride, the viscosity of supercritical carbon dioxide increased to 3.1 and 1.1 times, respectively.

[0077] Example 2

[0078] Preparation of aminofluoropolyacrylate A:

[0079] 1 mol of perfluorohexyl ethyl acrylate, 0.2 mol of 3-amino-1-propene, and 5 mol of tetrahydrofuran were stirred into a homogeneous solution. The solution was then added to a reactor equipped with a reflux condenser. Nitrogen gas was purged for 30 min to remove oxygen. Azobisisobutyronitrile was then added to the reactor, and nitrogen gas was continuously purged. The system temperature was maintained at 50°C in a water bath. The mixture was refluxed and reacted for 6 hours. The solvent was removed by vacuum drying to obtain amino-fluoropolyacrylate A, with a total yield of 97%.

[0080] The structure of aminofluoropolyacrylate A is as follows:

[0081] Where R1 is -H; R3 is -C8H4F 13 R4 is -H, R5 is -CH2-; its m:n = 1:0.2 was determined by 1H NMR spectroscopy; its number-average molecular weight was 5130 by GPC spectroscopy.

[0082] Preparation of carbon dioxide thickener:

[0083] The synthesized aminofluoropolyacrylate A and glyceryl tartrate were mixed at a molar ratio of 1:3 and stirred at 300 rpm for 30 min to obtain a carbon dioxide thickener.

[0084] The above-mentioned carbon dioxide thickener was mixed with supercritical carbon dioxide at a volume ratio of 1.5:100 and injected into a 1 / 16-inch stainless steel capillary tube. The injection rate of the mixture was 5.0 mL / min, the temperature was controlled at 40℃, and the back pressure was 40 MPa. The pressure difference ΔP2 between the front and rear ends was measured and recorded when the injection was balanced using a differential pressure gauge.

[0085] The experimental results showed that ΔP² = 33.7 and R = 18.7.

[0086] The calculation process is the same as in Example 1. After adding carbon dioxide thickener, the viscosity of supercritical carbon dioxide increased by 18.7 times.

[0087] Comparative Example 2

[0088] The above-mentioned aminofluoropolyacrylate A was mixed with supercritical carbon dioxide at a volume ratio of 1.5:100 and injected into a 1 / 16-inch stainless steel capillary tube. The injection rate of the mixture was 5.0 mL / min, the temperature was controlled at 40℃, and the back pressure was 40 MPa. The pressure difference ΔP between the front and rear ends at the injection equilibrium was measured and recorded using a differential pressure gauge. 2-1 .

[0089] The above-mentioned glyceryl tartrate was mixed with supercritical carbon dioxide at a ratio of 1.5:100 and injected into a 1 / 16-inch stainless steel capillary tube. The injection rate of the mixture was 5.0 mL / min, the temperature was controlled at 40 °C, and the back pressure was 40 MPa. The pressure difference ΔP between the front and rear ends at injection equilibrium was measured and recorded using a differential pressure gauge. 2-1 .

[0090] The experimental results show that: ΔP 1-1 =11.0, ΔP 1-1 =2.3,

[0091] The calculation process was the same as in Example 1. After adding amino-fluoropolyacrylate A and triglyceride tripropionate respectively, the supercritical carbon dioxide viscosity increased to 6.1 and 1.3 times.

[0092] Example 3

[0093] Preparation of carbon dioxide thickener:

[0094] The aminofluoropolyacrylate A synthesized in Example 2 was mixed with dipropylene glycol dimethyl ether at a molar ratio of 1:2 for 30 minutes under stirring at 300 rpm to obtain a carbon dioxide thickener.

[0095] The above-mentioned carbon dioxide thickener was mixed with supercritical carbon dioxide at a volume ratio of 3:100 and injected into a 1 / 16-inch stainless steel capillary tube. The injection rate of the mixture was 5.0 mL / min, the temperature was controlled at 40℃, and the back pressure was 40 MPa. The pressure difference ΔP2 between the front and rear ends was measured and recorded when the injection was balanced using a differential pressure gauge.

[0096] The experimental results showed that ΔP² = 40.0 and R = 22.2.

[0097] The calculation process is the same as in Example 1. After adding carbon dioxide thickener, the viscosity of supercritical carbon dioxide increased by 22.2 times.

[0098] Example 4

[0099] Preparation of aminofluoropolyacrylate B:

[0100] 1 mol of 2-(perfluorodecyl)ethyl methacrylate, 0.15 mol of acrylamide, and 6 mol of tetrahydrofuran were stirred into a homogeneous solution. The solution was then added to a reactor equipped with a reflux condenser. Nitrogen gas was purged for 30 min to remove oxygen. Azobisisobutyronitrile was then added to the reactor, and nitrogen gas was continuously purged. The system temperature was maintained at 50°C in a water bath. The mixture was refluxed and reacted for 5 hours. The solvent was removed by vacuum drying to obtain aminofluoropolyacrylate B, with a total yield of 98%.

[0101] The structure of aminofluoropolyacrylate B is as follows:

[0102] Where R1 is -H; R3 is -C 12 H4F 21 R4 is -CH3, R5 is C=O; its m:n = 1:0.15 was determined by 1H NMR spectroscopy; its number-average molecular weight was 6089 by GPC spectroscopy.

[0103] Preparation of carbon dioxide thickener:

[0104] The synthesized aminofluoropolyacrylate B and glyceryl tribonitrile were mixed at a molar ratio of 1:1 and stirred at 300 rpm for 30 min to obtain a carbon dioxide thickener.

[0105] The above-mentioned carbon dioxide thickener was mixed with supercritical carbon dioxide at a volume ratio of 1:100 and injected into a 1 / 16-inch stainless steel capillary tube. The injection rate of the mixture was 5.0 mL / min, the temperature was controlled at 40℃, and the back pressure was 40 MPa. The pressure difference ΔP2 between the front and rear ends was measured and recorded when the injection was balanced using a differential pressure gauge.

[0106] The experimental results showed that ΔP² = 29.3 and R = 16.3.

[0107] The calculation process is the same as in Example 1. After adding carbon dioxide thickener, the viscosity of supercritical carbon dioxide increased by 16.3 times.

[0108] As can be seen from Examples 1-4 and Comparative Examples 1-2, the carbon dioxide viscosity enhancer of the present invention increases the viscosity by more than 10 times, preferably more than 15 times, compared with pure carbon dioxide, thereby effectively increasing the carbon dioxide sweep efficiency and improving the recovery rate.

Claims

1. A carbon dioxide viscosity increasing agent, comprising an amine-based compound and a second compound, the second compound being at least one of an ether bond-containing compound and an ester bond-containing compound, the amine-based compound being at least one of an amine-based structure-containing compound comprising a primary amine and / or a secondary amine, a moiety connected to the amine group in the amine-based compound being at least one of a fluorinated polyacrylate group, a polysiloxane group, a long-chain alkyl group, and a fluorinated alkyl group, and a total number of ether bonds and ester bonds in the second compound being at least two. 2.The carbon dioxide viscosity increasing agent according to claim 1, wherein the moiety connected to the amine group in the amine-based compound is at least one of a fluorinated polyacrylate group and a polysiloxane group. 3.The carbon dioxide viscosity increasing agent according to claim 1, wherein when the moiety connected to the amine group is a fluorinated polyacrylate group, the amine-based compound has a structure represented by formula (I) : R 1 R 2 NHR 3 (I). 4.The carbon dioxide viscosity increasing agent according to claim 3, wherein m: n = 1: (0.1-0.3), and when the moiety connected to the amine group is a fluorinated polyacrylate group, the amine-based compound has a number average molecular weight of 4000-7000. 5.The carbon dioxide viscosity increasing agent according to claim 1, wherein when the moiety connected to the amine group is a polysiloxane group, the amine-based compound has a structure represented by formula (II) : R 1 R 2 NHR 3 (II), wherein R 1 is one of -H, -CH 3, -CH 2CH 3, -CH 2CH 2CH 3, -CH 2OH, -C 2H 4OH, and -C 3H 6OH; R 6 is a C 1-C 5 alkylene group or an ester group; p: q = 1: (0.1-0.5), and when the moiety connected to the amine group is a polysiloxane group, the amine-based compound has a number average molecular weight of 1000-20000. Formula (I); wherein R1 is one of -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, -C3H6OH; R3 is a fluoroalkyl group having from 4 to 10 carbon atoms, and the ratio of H to F in R3 is (0-0.5):1; R4 is -H or -CH3, R5 is a C1-C5 alkylene or carbonyl group; m:n = 1:(0.1-1); and the number average molecular weight of the amine compound is from 1000 to 10000 when the moiety attached to the amine group is a fluoro-polyacrylate group. 12 wherein R1 is one of -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, -C3H6OH; R3 is a fluoroalkyl group having from 4 to 10 carbon atoms, and the ratio of H to F in R3 is (0-0.5):1; R4 is -H or -CH3, R5 is a C1-C5 alkylene or carbonyl group; m:n = 1:(0.1-1); and the number average molecular weight of the amine compound is from 1000 to 10000 when the moiety attached to the amine group is a fluoro-polyacrylate group. 6.The carbon dioxide viscosity increasing agent according to claim 5, wherein p: q = 1: (0.1-0.3), and when the moiety connected to the amine group is a polysiloxane group, the amine-based compound has a number average molecular weight of 6000-10000. 7.The carbon dioxide viscosity increasing agent according to claim 1, wherein when the moiety connected to the amine group is a long-chain alkyl group, the amine-based compound has a structure represented by formula (III) : R 7 NHR 1 (III). 8.The carbon dioxide viscosity increasing agent according to claim 7, wherein R 7 is one of a C 1-C 5 alkyl group and a C 1-C 5 fluorinated alkyl group. 9.The carbon dioxide viscosity increasing agent according to claim 1, wherein when the moiety connected to the amine group is a fluorinated alkyl group, the amine-based compound has a structure represented by formula (IV) : R 8 NHR 1 (IV). Formula (II); 10.The carbon dioxide viscosity increasing agent according to claim 9, wherein R 8 is one of a C 1-C 5 alkyl group and a C 1-C 5 fluorinated alkyl group. 11.The carbon dioxide viscosity increasing agent according to claim 1, wherein the ether bond-containing compound is at least one of compounds represented by formula (V) : R 1 R 2 NHR 3 (V), and the ester bond-containing compound is at least one of compounds represented by formula (VI) : R 1 R 2 NHR 3 (VI). 12.The carbon dioxide viscosity increasing agent according to claim 11, wherein the ether bond-containing compound is at least one of compounds represented by formula (V) : R 1 R 2 NHR 3 (V), and the ester bond-containing compound is at least one of compounds represented by formula (VI) : R 1 R 2 NHR 3 (VI). ​ ​ ​ wherein R7is C 10 -C 24 a fatty alkyl group; R1is one of -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, -C3H6OH. ​ R7is C 10 -C 20 aliphatic hydrocarbon group. ​ ​ ​ wherein R8 is perfluorinated or partially fluorinated C6-C 24 alkyl, and the ratio of H to F in R8 is less than or equal to 1 : 1; R1 is one of -H, -CH3, -CH2CH3, -CH2CH2CH3, -CH2OH, -C2H4OH, -C3H6OH. ​ R8is perfluorinated or partially fluorinated C6-C 20 alkyl, and the ratio of H to F in R8is less than or equal to 1 :

1. ​ ​ Formula (V); and / or, ​ Formula (VI); In the above formula (V) and formula (VI), R9and R 10 each independently is C1-C6alkyl or aryl; R 9 and R 10 each independently is C1-C6alkyl or aryl; R2each independently is C1-C3alkylene, substituted C1-C3alkylene, or -R 11 OR 12 -, wherein R 11 and R 12 each independently is C1-C6alkyl or aryl. ​ The substituent in the substituted C1-C3 alkylene group is a C1-C6 alkyl group or an aryl group or a C1-C6 alkyl group or aryl group substituted ester group.

13. The carbon dioxide viscosity increasing agent according to any one of claims 1 to 12, wherein: The molar ratio of the amine-based compound to the second compound is 1: (0.5-10).

14. The carbon dioxide viscosity increasing agent according to claim 13, wherein: The molar ratio of the amine-based compound to the second compound is 1: (0.5-6).

15. A method for producing the carbon dioxide viscosity increasing agent according to any one of claims 1 to 14, comprising the step of thoroughly mixing components including the amine-based compound and the second compound.

16. A method for increasing the viscosity of carbon dioxide, comprising mixing the carbon dioxide with the carbon dioxide viscosity increasing agent according to any one of claims 1 to 14 or produced by the method according to claim 15.

17. The method according to claim 16, wherein: The method comprises the step of alternately or simultaneously injecting the carbon dioxide viscosity increasing agent into a porous medium containing crude oil with carbon dioxide or mixing the carbon dioxide viscosity increasing agent with carbon dioxide and then injecting the mixture into the porous medium.

18. The method according to claim 17, wherein: The carbon dioxide is supercritical and / or liquid carbon dioxide.

19. The method according to claim 16, wherein: The hydrogen group in the amine-based compound and the oxygen group in the second compound are associated in carbon dioxide to form an association.

20. The method according to claim 16, wherein: The volume ratio of the carbon dioxide viscosity increasing agent to carbon dioxide is (0.1-5):

100.

21. The method according to claim 20, wherein: The volume ratio of the carbon dioxide viscosity increasing agent to carbon dioxide is (0.3-3):

100.

22. Use of the carbon dioxide viscosity increasing agent according to any one of claims 1 to 14 or produced by the method according to claim 15 for increasing the viscosity of carbon dioxide.

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