Carbon dioxide viscosity-increasing modifiers, oil displacement agents, and uses thereof, and methods for increasing carbon dioxide viscosity and carbon dioxide-in-oil dispersions

Abstract

The present application relates to the technical field of enhanced oil recovery, in particular to a carbon dioxide viscosity-increasing regulator, an oil displacement agent, application thereof, a method for increasing carbon dioxide viscosity and a carbon dioxide-in-oil dispersion system. The carbon dioxide viscosity-increasing regulator comprises at least one compound represented by formula (I); (R1) a (DO j PO k EO h ) b [X1(C=OR2) c (C=O) d (X2) e R3] f Formula (I). The carbon dioxide viscosity-increasing regulator reduces the interfacial tension between crude oil and carbon dioxide, and the oil displacement agent formed by carbon dioxide is applied to crude oil exploitation, which is conducive to the dispersion of carbon dioxide in crude oil to form a carbon dioxide-in-oil dispersion system. The viscosity of carbon dioxide in the carbon dioxide-in-oil dispersion system is 1-2000 times the viscosity of carbon dioxide under the same temperature and pressure conditions.

Description

Technical Field

[0001] This invention relates to the field of enhanced oil recovery technology, specifically to a carbon dioxide viscosity modifier, an oil displacement agent and its application, a method for improving carbon dioxide viscosity, and an oil-in-oil carbon dioxide dispersion system. Background Technology

[0002] Due to the potential greenhouse effect of carbon dioxide, its comprehensive utilization has become a hot topic. Carbon dioxide flooding is an important way to achieve its comprehensive utilization and effective storage. As a traditional method to enhance oil recovery, carbon dioxide flooding can effectively improve injection capacity and avoid water sensitivity, making it one of the important ways to improve the recovery rate of low-permeability reservoirs. For some light oil reservoirs, the theoretical recovery rate of carbon dioxide miscible flooding can reach over 90%, while most heavy oil reservoirs cannot achieve carbon dioxide miscible flooding. This is because during the carbon dioxide displacement process, the large contrast between the viscosity of underground crude oil and injected carbon dioxide leads to an unfavorable mobility ratio, resulting in early carbon dioxide breakthrough, reduced reservoir sweep efficiency, and decreased oil production. An important factor affecting carbon dioxide flooding is gas channeling. To achieve good oil displacement results, it is necessary to control gas channeling, adjust the gas injection profile, expand the gas sweep area, and maximize the contact between carbon dioxide and the remaining oil to improve oil washing efficiency, ultimately achieving the goal of improving oil recovery.

[0003] Due to its low dielectric constant and high efficiency per unit volume, supercritical carbon dioxide is a very weak solvent for most compounds and has poor affinity for crude oil, especially heavy oil. Therefore, research on increasing the viscosity of the displacing phase carbon dioxide to achieve flow control has attracted considerable attention. Polymers with a relatively high affinity for carbon dioxide, such as polyvinyl acetate (PVAc), contain multiple active sites such as ester groups that can interact with carbon dioxide molecules. However, even with these advantages, dissolving 5 wt% of PVAc with a degree of polymerization of 8000 requires a pressure as high as 75 MPa at room temperature, and the thickening effect is not satisfactory. Therefore, the search for effective chemical agents and methods for thickening carbon dioxide is urgently needed. Summary of the Invention

[0004] The purpose of this invention is to overcome the problem of low viscosity of the carbon dioxide displacement phase in existing technologies, and to provide a carbon dioxide viscosity modifier, an oil displacement agent, their applications, a method for improving carbon dioxide viscosity, and an oil-in-oil carbon dioxide dispersion system. The carbon dioxide viscosity modifier of this invention reduces the interfacial tension between crude oil and carbon dioxide. The oil displacement agent formed with carbon dioxide, when applied to crude oil extraction, facilitates the dispersion of carbon dioxide in crude oil, forming an oil-in-oil carbon dioxide dispersion system. The viscosity of carbon dioxide in the oil-in-oil carbon dioxide dispersion system is 1-2000 times that of carbon dioxide under the same temperature and pressure conditions.

[0005] To achieve the above objectives, a first aspect of the present invention provides a carbon dioxide viscosity modifier, the modifier comprising at least one of the compounds represented by formula (I);

[0006] (R1) a (DO j PO k EO h ) b [X1 (C=OR2) c (C=O) d (X2) e R3] f Formula (I),

[0007] In equation (I), R1 and R3 are each independently selected from hydrogen, C1-C 24 hydrocarbon group;

[0008] a is the number of R1 groups, a = 1 or 2;

[0009] R2 is selected from C1-C 18 The alkylene group;

[0010] DO represents the epoxide butane fragment, and j represents the number of epoxide butane fragments;

[0011] PO represents the propylene oxide fragment, and k represents the number of propylene oxide fragments.

[0012] EO represents the ethylene oxide fragment, and h represents the number of ethylene oxide fragments;

[0013] j=0-20, k=0-20, h=0-20;

[0014] b = 0, 1, or 2; c = 0 or 1; d = 0 or 1; e = 0 or 1; f = 1-5;

[0015] X1 is selected from O, [N(R')-R 0 -] y N(R”) z One of them, R 0 Selected from C1-C 12 The alkylene group, R' is selected from hydrogen, C1-C6 alkyl groups, or DO. j1 PO k1 EO h1 One of H;

[0016] "R" is selected from hydrogen, C1-C6 hydrocarbon groups, or DO. j2 PO k2 EO h2H is one of the following; y = any integer from 0 to 5, z = 0 or 1; j1 and j2 are the number of butylene oxide fragments, k1 and k2 are the number of propylene oxide fragments, h1 and h2 are the number of ethylene oxide fragments, j1 and j2 are each any integer from 0 to 20, k1 and k2 are each any integer from 0 to 20, h1 and h2 are each any integer from 0 to 20;

[0017] X2 is selected from one of O, N and NH.

[0018] A second aspect of the present invention provides an oil displacement agent comprising the regulator described in the present invention and carbon dioxide, wherein the mass ratio of the regulator to carbon dioxide is 0.001-1:1.

[0019] A third aspect of the present invention provides a method for increasing the viscosity of carbon dioxide, the method comprising: mixing crude oil, the regulator described in the present invention, and carbon dioxide to obtain a stable dispersion system of carbon dioxide in oil.

[0020] The fourth aspect of the present invention provides an oil-in-carbon dioxide dispersion system, wherein the oil contains crude oil and the regulator described in the present invention, the mass ratio of the regulator to carbon dioxide is 0.001-1:1, and the viscosity of the crude oil is not less than 100 mPa·s.

[0021] The fifth aspect of this invention provides the application of the regulator and oil displacement agent described in this invention in crude oil extraction.

[0022] Through the above technical solution, the regulator of the present invention can increase the viscosity of carbon dioxide during the oil displacement process. For crude oils of different viscosities, by introducing oxygen or nitrogen atoms, especially carbonyl groups, into the regulator molecule, it has a good affinity with carbon dioxide. At the same time, due to the presence of lone pairs of electrons, it also has a strong interaction with polar substances in crude oil, which strengthens the interaction between carbon dioxide and different crude oils, effectively enhances the viscosity of carbon dioxide, and thus helps to improve the efficiency of carbon dioxide extraction.

[0023] Furthermore, when the regulators and oil displacement agents of this invention are applied to crude oil extraction, they can increase the viscosity of carbon dioxide during the oil displacement process. In the resulting oil-encapsulated carbon dioxide dispersion system, the viscosity of carbon dioxide is 1-2000 times that under the same temperature and pressure conditions, which shows good application potential in carbon dioxide oil recovery operations. Attached Figure Description

[0024] Figure 1 This is an HPLC analysis chromatogram of the distribution of PO and EO products in regulators I-1 and I-2 in the embodiments of the present invention;

[0025] Figure 2 This is an external view of the oil-in-carbon dioxide system of Embodiment 1 of the present invention;

[0026] Figure 3 This is a diagram of the miscible or near-miscible system formed in Examples 8-10 of the present invention;

[0027] Figure 4 This is a schematic diagram of the process for detecting the viscosity of the carbon dioxide phase in the oil-in-carbon dioxide system of the present invention. Detailed Implementation

[0028] 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.

[0029] A first aspect of the present invention provides a carbon dioxide viscosity modifier, the modifier comprising at least one of the compounds represented by formula (I);

[0030] (R1) a (DO j PO k EO h ) b [X1 (C=OR2) c (C=O) d (X2) e R3] f Formula (I),

[0031] In equation (I), R1 and R3 are each independently selected from hydrogen, C1-C 24 hydrocarbon group;

[0032] a is the number of R1 groups, a = 1 or 2;

[0033] R2 is selected from C1-C 18 The alkylene group;

[0034] DO represents the epoxide butane fragment, and j represents the number of epoxide butane fragments;

[0035] PO represents the propylene oxide fragment, and k represents the number of propylene oxide fragments.

[0036] EO represents the ethylene oxide fragment, and h represents the number of ethylene oxide fragments;

[0037] j=0-20, k=0-20, h=0-20;

[0038] b = 0, 1, or 2; c = 0 or 1; d = 0 or 1; e = 0 or 1; f = 1-5;

[0039] X1 is selected from O, [N(R')-R 0 -] y N(R”) z One of them, R 0 Selected from C1-C 12 The alkylene group, R' is selected from hydrogen, C1-C6 alkyl groups, or DO. j1 PO k1 EO h1 One of H;

[0040] "R" is selected from hydrogen, C1-C6 hydrocarbon groups, or DO. j2 PO k2 EO h2 H is one of the following; y = any integer from 0 to 5, z = 0 or 1; j1 and j2 are the number of butylene oxide fragments, k1 and k2 are the number of propylene oxide fragments, h1 and h2 are the number of ethylene oxide fragments, j1 and j2 are each any integer from 0 to 20, k1 and k2 are each any integer from 0 to 20, h1 and h2 are each any integer from 0 to 20;

[0041] X2 is selected from O, N, and NH. The regulator described in this invention reduces the interfacial tension between crude oil and carbon dioxide. The oil displacement agent formed with carbon dioxide, when applied to crude oil extraction, facilitates the dispersion of carbon dioxide in crude oil, forming an oil-in-carbon dioxide dispersion system.

[0042] In this invention, hydrocarbon groups and hydrocarbon subgroups include straight-chain hydrocarbon groups and branched hydrocarbon groups.

[0043] According to a preferred embodiment of the present invention, in formula (I), R1 and R3 are each independently selected from hydrogen, C1-C1, C2-C3, C4-C5, C6-C6-C5-C6 ... 20 Hydrocarbon group.

[0044] According to a preferred embodiment of the present invention, in formula (I), R2 is selected from C1-C 10 The alkylene groups are beneficial for further enhancing the viscosity of the carbon dioxide phase.

[0045] According to a preferred embodiment of the present invention, in formula (I), X1 is selected from [N(R')-R 0 -] y N(R”) z At that time, R 0 Selecting alkylene groups from C1-C6 is beneficial for further enhancing the viscosity of the carbon dioxide phase.

[0046] According to a preferred embodiment of the present invention, in formula (I), X1 is selected from [N(R')-R 0 -] y N(R”) z In this case, R' is selected from hydrogen, C1-C3 hydrocarbon groups, or DO.j1 PO k1 EO h1 One of H is beneficial for further enhancing the viscosity of the carbon dioxide phase.

[0047] According to a preferred embodiment of the present invention, in formula (I), X1 is selected from [N(R')-R 0 -] y N(R”) z In this case, "R" is selected from hydrogen, C1-C3 hydrocarbon groups, or DO. j2 PO k2 EO h2 One of H is beneficial for further enhancing the viscosity of the carbon dioxide phase.

[0048] According to a preferred embodiment of the present invention, in formula (I), a = 1 or 2.

[0049] According to a preferred embodiment of the present invention, in formula (I), b = 0, 1 or 2.

[0050] According to a preferred embodiment of the present invention, in formula (I), c = 0 or 1.

[0051] According to a preferred embodiment of the present invention, in formula (I), d = 0 or 1.

[0052] According to a preferred embodiment of the present invention, in formula (I), e = 0 or 1.

[0053] According to a preferred embodiment of the present invention, in formula (I), f = 1-3.

[0054] According to a preferred embodiment of the present invention, in formula (I), X1 is selected from [N(R')-R 0 -] y N(R”) z When y = 0 or 1, z = 0 or 1.

[0055] According to a preferred embodiment of the present invention, in formula (I), j = 0-10.

[0056] According to a preferred embodiment of the present invention, in formula (I), k = 0-10.

[0057] According to a preferred embodiment of the present invention, in formula (I), h = 0-10.

[0058] According to a preferred embodiment of the present invention, in formula (I), X1 is selected from [N(R')-R 0 -] y N(R”) z When, R' is selected from DO j1 PO k1 EOh1 When H, j1 = 0-10; and / or k1 = 0-10; and / or h1 = 0-10.

[0059] According to a preferred embodiment of the present invention, in formula (I), X1 is selected from [N(R')-R 0 -] y N(R”) z When, "R" is selected from DO j2 PO k2 EO h2 When H, j2 = 0-10; and / or k2 = 0-10; and / or h2 = 0-10.

[0060] In this invention, in formula (I), j+j1+j2 is the total number of butane oxide fragments, k+k1+k2 is the total number of propylene oxide fragments, and h+h1+h2 is the total number of ethylene oxide fragments.

[0061] According to a preferred embodiment of the present invention, in formula (I), R1 is selected from H, -CH3, -C2H5, -C3H7 or -(CH2)(CH)(CH2).

[0062] According to a preferred embodiment of the present invention, in formula (I), R2 is -CH2-.

[0063] According to a preferred embodiment of the present invention, in formula (I), R3 is selected from -C3H7, -C6H5, and -C 10 H 21 -C 11 H 23 or -C 18 H 35 (Oil-based)

[0064] According to a preferred embodiment of the present invention, in formula (I), X1 is selected from -O, -N, -NHC3H6NH, -NC3H6N(CH3), -NHC3H6NHC3H6NH, -N(EO) h1 H)C3H6N(EO h2 H) or -N(PO) k1 H)C3H6N(PO K2 H).

[0065] According to a preferred embodiment of the present invention, the regulator is selected from one or more compounds represented by formula (I-1), formula (I-2), formula (I-3), formula (I-4), formula (I-5), formula (I-6), and formula (I-7);

[0066] Equation (I-1): In equation (I), R1 is H, a = 2, X1 is H, c = 0, d = 0, e = 0, and R3 is -C. 18 H35 , f=1, j=0, k=5, h=0, b=2;

[0067] Equation (I-2): In equation (I), R1 is H, a = 2, X1 is H, c = 0, d = 0, e = 0, and R3 is -C. 18 H 35 , f=1, j=0, k=0, h=5, b=2;

[0068] Equation (I-3): In equation (I), R1 is H, a = 1, X1 is -NHC3H6NH, c = 0, d = 0, e = 0, and R3 is -C 18 H 35 , f=1, j=0, k=0, h=0, b=0;

[0069] Equation (I-4): In equation (I), R1 is H, a = 1, and X1 is -N(EO). h1 H)C3H6N(EO h2 H), c = 0, d = 0, e = 0, R3 is -C 18 H 35 , f=1, b=1, j=0, k=0, h+h1+h2=5;

[0070] Equation (I-5): In equation (I), R1 is H, a = 1, and X1 is -N(PO) k1 H)C3H6N(PO K2 H), c = 0, d = 0, e = 0, R3 is -C 18 H 35 , f=1, b=1, j=0, h=0, k+k1+k2=5;

[0071] Equation (I-6): In equation (I), R1 is H, a = 1, X1 is -NHC3H6NHC3H6NH, c = 0, d = 0, e = 0, and R3 is -C 18 H 35 , f=1, j=0, k=0, h=0, b=0;

[0072] Equation (I-7): In equation (I), R1 is -CH3, a = 2, and X1 is - NC3H6N(CH3) c = 0, d = 0, e = 0, R3 is -C 18 H 35 , f=1, j=0, k=0, h=0, b=0.

[0073] A second aspect of this invention provides an oil displacement agent comprising the regulator described herein and carbon dioxide, wherein the mass ratio of the regulator to carbon dioxide is 0.001-1:1. When mixed with crude oil, the oil displacement agent of this invention can increase the viscosity, which is comparable to the viscosity of carbon dioxide under the same temperature and pressure conditions, demonstrating good application potential in carbon dioxide-based oil recovery operations.

[0074] In this invention, the mass ratio of regulator to carbon dioxide in the oil displacement agent can be selected within a wide range. This is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of regulator to carbon dioxide is 0.001-0.1:1, for example, 0.002:1, 0.003:1, 0.005:1, or 0.008:1. Within the aforementioned range, it is beneficial to further enhance the viscosity of carbon dioxide.

[0075] In the oil displacement agent described in this invention, the form of carbon dioxide can be selected from a wide range. This is an illustrative example, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, carbon dioxide is selected from one or more of gaseous carbon dioxide, liquid carbon dioxide, and supercritical carbon dioxide.

[0076] A third aspect of this invention provides a method for increasing the viscosity of carbon dioxide, the method comprising: mixing crude oil, the regulator described in this invention, and carbon dioxide to obtain a stable dispersion system of carbon dioxide in oil. The carbon dioxide dispersion system formed by the method described in this invention significantly increases the viscosity of the carbon dioxide phase, which is 1-2000 times, preferably 2-2000 times, and more preferably 500-2000 times, the viscosity of carbon dioxide under the same temperature and pressure conditions.

[0077] According to a preferred embodiment of the present invention, in the oil-infused carbon dioxide dispersion system, crude oil is the continuous phase and carbon dioxide is the dispersed phase.

[0078] According to one embodiment of the present invention, the crude oil contains C6-C. 20 Alkanes.

[0079] According to a preferred embodiment of the present invention, the oil in the dispersion system is crude oil with a viscosity greater than 1 mPa·s, preferably crude oil with a viscosity of 2-200000 mPa·s, more preferably 10-100000 mPa·s, and even more preferably crude oil with a viscosity of 10-6000 mPa·s.

[0080] In this invention, the mass ratio of crude oil to regulator in the dispersion system can be selected within a wide range. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio is 1:0.01-0.1, for example, 1:0.02, 1:0.05, 1:0.08, 1:0.1, preferably 1:0.05-0.1.

[0081] In this invention, the form of carbon dioxide in the dispersion system can be selected from a wide range. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, carbon dioxide is selected from one or more of gaseous carbon dioxide, liquid carbon dioxide, and supercritical carbon dioxide, more preferably supercritical carbon dioxide and / or liquid carbon dioxide.

[0082] A fourth aspect of this invention provides an oil-in-oil carbon dioxide dispersion system, wherein the oil in the dispersion system contains crude oil and the regulator described in this invention; the viscosity of the crude oil is not less than 100 mPa·s; and the mass ratio of crude oil to regulator is 1:0.01-0.1. Compared with carbon dioxide under the same temperature and pressure conditions, the viscosity of the oil-in-oil carbon dioxide dispersion system described in this invention is significantly increased, which is beneficial to improving the efficiency of carbon dioxide extraction from crude oil.

[0083] In this invention, the mass ratio of crude oil to regulator in the dispersion system can be selected within a wide range. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, the mass ratio of crude oil to regulator is 1:0.01-0.1, for example, 1:0.02, 1:0.03, 1:0.04, 1:0.05, 1:0.06, or 1:0.08.

[0084] According to a preferred embodiment of the present invention, in the oil-infused carbon dioxide dispersion system, crude oil is the continuous phase and carbon dioxide is the dispersed phase.

[0085] According to a preferred embodiment of the present invention, in the dispersion system, the viscosity of the crude oil is 100-6000 mPa·s, more preferably 500-6000 mPa·s.

[0086] According to a preferred embodiment of the present invention, the regulator, in formula (1), X1 is selected from [N(R')-R 0 -] y N(R”) z One of them, R 0 Selected from C1-C 12 The alkylene group, R' is selected from hydrogen, C1-C6 alkyl groups, or DO. j1 PO k1 EO h1 One of H; R" is selected from hydrogen, C1-C6 hydrocarbon groups, or DO. j2 PO k2 EO h2One of H; y = any integer from 1 to 5, z = 0 or 1; j1 and j2 are the number of butane oxide fragments, k1 and k2 are the number of propylene oxide fragments, h1 and h2 are the number of ethylene oxide fragments, j1 and j2 are each any integer from 0 to 20, k1 and k2 are each any integer from 0 to 20, h1 and h2 are each any integer from 0 to 20; X2 is selected from N and NH.

[0087] In this invention, the form of carbon dioxide in the dispersion system can be selected from a wide range. This is an illustrative example, but does not limit the scope of the invention. According to a preferred embodiment of the invention, carbon dioxide is selected from one or more of gaseous carbon dioxide, liquid carbon dioxide, and supercritical carbon dioxide, more preferably supercritical carbon dioxide and / or liquid carbon dioxide.

[0088] The fifth aspect of this invention provides the application of the regulator and oil displacement agent described herein in crude oil extraction. The carbon dioxide viscosity modifier of this invention reduces the interfacial tension between crude oil and carbon dioxide. When applied to crude oil extraction, the oil displacement agent formed with carbon dioxide facilitates the dispersion of carbon dioxide in crude oil, forming an oil-in-oil carbon dioxide dispersion system. The viscosity of carbon dioxide in the oil-in-oil carbon dioxide dispersion system is 1-2000 times that of carbon dioxide under the same temperature and pressure conditions.

[0089] According to a preferred embodiment of the present invention, the reservoir conditions include: reservoir temperature of 40-200℃ and formation pressure of 5-45MPa.

[0090] In this invention, the viscosity of crude oil in crude oil extraction can be selected from a wide range. This is an illustrative example, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the crude oil viscosity is greater than 1 mPa·s, preferably 2-200000 mPa·s, more preferably 10-100000 mPa·s, and even more preferably 10-6000 mPa·s.

[0091] To further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims of the present invention.

[0092] In this invention, when referring to the mass of the regulator, it refers to the total mass of compounds containing the general molecular formula (I) in the above-mentioned technical solution.

[0093] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this invention are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0094] In the context and embodiments of this invention, the viscosity of crude oil was measured using a Thermo Fisher Scientific Viscotester IQ Air rotational rheometer under the following conditions: 7.34 s. -1 50℃.

[0095] In the context and embodiments of this invention, referring to standard Q / SH 32100065-2012, the content of four components in crude oil was determined using an IATROSCAN MK-6S thin-layer chromatograph. The four components are saturated hydrocarbons, aromatic hydrocarbons, resins, and asphaltenes. The component content of crude oil in the embodiments of this invention is shown in Table 1.

[0096] Table 1

[0097]

[0098] In the context and embodiments of this invention, the liquid chromatography analysis conditions are: 25°C, XBridge C18-3.5um 2.1*150mm, 200mM AA, pH 6.

[0099] In the context and embodiments of this invention, the mass fraction of carbon dioxide (CO2%) is calculated as follows:

[0100] V 二氧化碳 =21.95-(m oil / ρ oil + m 调节剂 / ρ 调节剂 ) Formula (1)

[0101] m 二氧化碳 = V 二氧化碳 × ρ 二氧化碳 (P m Formula (2)

[0102] CO2% = m 二氧化碳 ×100 / ( m 二氧化碳 + m oil +m 调节剂 ) Formula (3)

[0103] Wherein, 21.95: maximum vessel volume, mL; m oil : Mass of crude oil, g; ρ oil Density of crude oil, g / mL; m 调节剂 : Mass of regulator, g; ρ 增效剂 : Density of the regulator, g / mL; V 二氧化碳 Volume of carbon dioxide (P) m (T), mL; m 二氧化碳 Mass of carbon dioxide (P) m ,T), g;ρ 二氧化碳Carbon dioxide density (P) m ,T), g / mL.

[0104] Carbon dioxide viscosity observation method: Using imaging method, in a supercritical visible volume system, the phase change of the synergist / crude oil / carbon dioxide system is observed to see whether a crude oil-in-carbon dioxide dispersion system or a miscible or near-miscible system can be formed (the crude oil being basically extracted by carbon dioxide ≥90% is considered to form a crude oil-in-carbon dioxide dispersion system or a miscible or near-miscible system), thereby determining whether the carbon dioxide phase viscosity increases.

[0105] Preparation Examples 1-10, Examples 1-15, and Comparative Examples 1-3

[0106] The compounds with the structural formulas shown in Table 2 were mixed according to the mass ratios in Table 3 to prepare the regulator. This regulator, along with crude oil, was weighed into a quartz dish equipped with a stirrer according to the mass ratios shown in Table 4. The dish was placed in a viewing system with the largest possible volume. The mixture was ventilated with carbon dioxide at <0.5 MPa 1-2 times, and the temperature was raised to 50°C while stirring. The pressure inside the dish was adjusted to P0 = 1.0 MPa. Stirring was stopped, and the mixture was allowed to stand for 1 hour. The appearance of the regulator / heavy oil / carbon dioxide system was photographed and recorded. The pressure P0 was gradually increased. i After stirring for 10 minutes each time, the mixture was allowed to stand for 50 minutes. Photos were taken and the pressure Pm at which a stable dispersion system or a near-miscible system was formed was recorded. The mass fractions of crude oil and carbon dioxide were calculated, and the results are shown in Table 4.

[0107] HPLC analysis was performed on regulators I-1 and I-2. The product structure was analyzed by HPLC under the following conditions: 25℃, XBridge C18-3.5um 2.1×150mm, 200mM AA, pH 6. Figure 1 Distribution of PO and EO products with different polymerization numbers for oleylamines.

[0108] Table 2

[0109]

[0110]

[0111] Table 3

[0112]

[0113] Table 4

[0114]

[0115]

[0116] As can be seen from Table 4, regulators I-1 to I-7 can all form an oil-in-oil carbon dioxide dispersion system with crude oil #1. Figure 2The image shows the appearance of the in-oil carbon dioxide dispersion system formed by I-1 and No. 1 crude oil, at a pressure of 14.52 MPa. Modifiers I-8 to I-10 can form a miscible or near-miscible system with No. 2 crude oil or hexadecane. Compared to Example 1, Comparative Example 1 could not form an in-oil carbon dioxide dispersion system. The results of Comparative Example 2 indicate that, without the addition of modifiers, No. 1 crude oil and carbon dioxide cannot form an in-oil carbon dioxide dispersion system. Comparative Example 3 similarly illustrates that, without the addition of modifiers, as... Figure 3 As shown, crude oil #2 and carbon dioxide are immiscible.

[0117] Test Example 1

[0118] A stainless steel capillary tube with a back pressure device is connected to the outlet end of a 250mL high-temperature and high-pressure phase equilibrium vessel. The phase equilibrium vessel is equipped with a piston and a magnetic rod. Figure 4 As shown. The high-temperature, high-pressure phase equilibrium vessel and capillary tube were cleaned and dried with petroleum ether. Following Examples 1-11, 20g of crude oil or hexadecane was weighed into the high-temperature, high-pressure phase equilibrium vessel. After purging the vessel with carbon dioxide at 100mL / min at room temperature and pressure to remove air, the corresponding conditioning agent was injected into the vessel using a high-pressure infusion pump. The carbon dioxide injection valve was opened, and carbon dioxide was slowly injected into the equilibrium vessel. The constant temperature bath was started, and the temperature and pressure inside the vessel were adjusted to 50℃ and P, respectively. m The pressure fluctuation during stirring equilibrium should not exceed 1%. Pure water is injected into the other end of the vessel at a constant flow rate, and the piston in the vessel is pushed to inject the oil-coated carbon dioxide dispersion system or the miscible-immiscible system into the capillary until equilibrium is reached. The pressure difference ΔP (Pa) between the front and rear ends at the injection equilibrium is measured and recorded using a differential pressure gauge. The viscosity μ of the system is calculated using the Poiseuille formula.

[0119]

[0120] Where μ is the viscosity of the system (Pa·s), and R is the inner radius of the capillary (8.5 × 10⁻⁶). -5 Q is the injection flow rate (1.67 × 10 m), where Q is the injection flow rate (1.67 × 10 m). -10 -1.67×10 -6 m 3 / s), where L is the capillary length (1m).

[0121] Test Example 2

[0122] The implementation process is the same as in Test Example 1, except that no regulator is added. Specifically:

[0123] After purging the reactor with carbon dioxide at a rate of 100 mL / min to remove all air, slowly inject carbon dioxide from the high-pressure storage tank into the phase equilibrium reactor, start the constant temperature bath, and adjust the temperature and pressure inside the reactor to 50℃ and P, respectively. mThe stirring equilibrium pressure fluctuation should not exceed 1%. Slowly open the outlet of the phase equilibrium vessel and inject supercritical carbon dioxide into the capillary until equilibrium is reached. Use a differential pressure gauge to test and record the pressure difference ΔP0 (Pa) between the front and rear ends when the injection reaches equilibrium. Use Poiseuille's formula to calculate the viscosity μ0 of the system.

[0124] Using P from Examples 1-15 respectively m Each test was conducted independently, and the increase in supercritical carbon dioxide viscosity R = μ / μ0 was calculated based on the pressure difference mentioned above. The results are shown in Table 5.

[0125] Table 5

[0126] Serial Number <![CDATA[μ0(mPa·s)]]> μ(mPa·s) R 1 0.054 102.354 1895.4 2 0.079 79.333 1004.2 3 0.085 51.231 602.7 4 0.076 57.889 761.7 5 0.052 88.401 1700.0 6 0.087 95.025 1092.2 7 0.080 49.211 615.1 8 0.087 0.259 3.0 9 0.076 0.141 1.9 10 0.087 0.198 2.3 11 0.088 0.215 2.4 12 0.071 23.227 327 13 0.069 90.483 1311 14 0.076 132.12 1738.4 15 0.083 82.411 992.9

[0127] The results above show that the carbon dioxide viscosity-enhancing method of this invention, after adding the regulator, allows crude oil #1 to form an oil-in-oil carbon dioxide dispersion system with a viscosity 603-1895 times that of pure carbon dioxide. Crude oil #2 can also form a miscible or near-miscible system with a viscosity 1.9-3.0 times that of pure carbon dioxide. When carbon dioxide is injected into the formation, it is highly likely to form an oil-in-oil carbon dioxide dispersion system if it encounters even a small amount of crude oil, or a miscible or near-miscible system if it encounters a large amount of crude oil. This significantly improves the efficiency of carbon dioxide extraction and has good application potential in carbon dioxide oil recovery operations.

[0128] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A carbon dioxide viscosity modifier, characterized in that, The regulator includes at least one of the compounds represented by formula (I); (R1) a (DO j PO k EO h ) b [X1 (C=OR2) c (C=O) d (X2) e R3] f Formula (I), In equation (I), R1 and R3 are each independently selected from hydrogen, C1-C 24 hydrocarbon group; a is the number of R1 groups, a = 1 or 2; R2 is selected from C1-C 18 The alkylene group; DO represents the epoxide butane fragment, and j represents the number of epoxide butane fragments; PO represents the propylene oxide fragment, and k represents the number of propylene oxide fragments. EO represents the ethylene oxide fragment, and h represents the number of ethylene oxide fragments; j=0-20, k=0-20, h=0-20; b = 0, 1, or 2; c = 0 or 1; d = 0 or 1; e = 0 or 1; f = 1-5; X1 is selected from O, [N(R')-R 0 -] y N(R”) z One of them, R 0 Selected from C1-C 12 The alkylene group, R' is selected from hydrogen, C1-C6 alkyl groups, or DO. j1 PO k1 EO h1 One of H; "R" is selected from hydrogen, C1-C6 hydrocarbon groups, or DO. j2 PO k2 EO h2 H is one of the following; y = any integer from 0 to 5, z = 0 or 1; j1 and j2 are the number of butylene oxide fragments, k1 and k2 are the number of propylene oxide fragments, h1 and h2 are the number of ethylene oxide fragments, j1 and j2 are each any integer from 0 to 20, k1 and k2 are each any integer from 0 to 20, h1 and h2 are each any integer from 0 to 20; X2 is selected from one of O, N and NH.

2. The regulator according to claim 1, wherein, R1 and R3 are each independently selected from hydrogen, C1-C 20 hydrocarbon groups; and / or, R2 is selected from C1-C 10 Hydroxyl groups; and / or, R 0 Selected from C1-C6 alkylene groups; and / or, R' is selected from hydrogen, C1-C3 hydrocarbon groups, or DO. j1 PO k1 EO h1 One of H; R" is selected from hydrogen, C1-C3 hydrocarbon groups, or DO. j2 PO k2 EO h2 One of H.

3. The regulator according to claim 1 or 2, wherein, a = 1 or 2; and / or, b = 0, 1, or 2; and / or, c = 0 or 1; and / or, d = 0 or 1; and / or, e = 0 or 1; and / or, f = 1-3; and / or, y = 0 or 1, z = 0 or 1.

4. The regulator according to claim 1 or 2, wherein, j = 0-10; and / or, k = 0-10; and / or, h = 0-10; and / or, h1 = 0-10, h2 = 0-10; and / or, k1 = 0-10, k2 = 0-10; and / or, j1 = 0-10, j2 = 0-10.

5. An oil displacement agent, characterized in that, The oil displacement agent comprises the regulator as described in any one of claims 1-4 and carbon dioxide, wherein the mass ratio of regulator to carbon dioxide is 0.001-1:1, preferably 0.001-0.1:

1.

6. The oil displacement agent according to claim 5, wherein, The carbon dioxide is selected from one or more of gaseous carbon dioxide, liquid carbon dioxide, and supercritical carbon dioxide.

7. A method for increasing the viscosity of carbon dioxide, characterized in that, The method includes: mixing crude oil, the regulator described in any one of claims 1-4, and carbon dioxide to obtain a stable dispersion system of carbon dioxide in oil.

8. The method according to claim 7, wherein, In the dispersion system, crude oil is the continuous phase and carbon dioxide is the dispersed phase; and / or The crude oil viscosity is greater than 1 mPa·s, preferably 2-200000 mPa·s, more preferably 10-6000 mPa·s; and / or The mass ratio of crude oil to regulator is 1:0.01-0.1; and / or Carbon dioxide is selected from one or more of gaseous carbon dioxide, liquid carbon dioxide, and supercritical carbon dioxide, preferably supercritical carbon dioxide and / or liquid carbon dioxide.

9. An oil-in-carbon dioxide dispersion system, characterized in that, In the dispersion system, the oil contains crude oil and the regulator as described in any one of claims 1-4, wherein the viscosity of the crude oil is not less than 100 mPa·s; and the mass ratio of crude oil to regulator is 1:0.01-0.

1. Preferably, in the dispersion system, crude oil is the continuous phase and carbon dioxide is the dispersed phase; and / or Preferably, the crude oil viscosity is 100-6000 mPa·s, more preferably 500-6000 mPa·s; Preferably, the carbon dioxide in the dispersion system is selected from one or more of gaseous carbon dioxide, liquid carbon dioxide, and supercritical carbon dioxide, and more preferably supercritical carbon dioxide and / or liquid carbon dioxide; Preferably, in formula (1), X1 is selected from [N(R')-R 0 -] y N(R”) z One of them, R 0 Selected from C1-C 12 The alkylene group, R' is selected from hydrogen, C1-C6 alkyl groups, or DO. j1 PO k1 EO h1 One of H; "R" is selected from hydrogen, C1-C6 hydrocarbon groups, or DO. j2 PO k2 EO h2 One of H; y = any integer from 1 to 5, z = 0 or 1; j1 and j2 are the number of butane oxide fragments, k1 and k2 are the number of propylene oxide fragments, h1 and h2 are the number of ethylene oxide fragments, j1 and j2 are each any integer from 0 to 20, k1 and k2 are each any integer from 0 to 20, h1 and h2 are each any integer from 0 to 20; X2 is selected from N and NH.

10. The application of the regulator according to any one of claims 1-4, or the oil displacement agent according to claim 5 or 6, in crude oil extraction; Preferably, the reservoir temperature is 40-200℃ and the formation pressure is 5-45MPa; Preferably, the crude oil viscosity is greater than 1 mPa·s, more preferably 2-200000 mPa·s, and even more preferably 10-6000 mPa·s.

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