Synergist as well as preparation method and application thereof

Abstract

The invention relates to the technical field of crude oil extraction, in particular to a synergist and a preparation method and application thereof. The structural formula of the synergist is shown as a formula (I); in the formula, R1 and R2 are respectively and independently selected from alkyl groups of C1 to C20, alkyl groups containing substituent groups of C1 to C20 and alkyl siloxy groups of C1 to C20; r3 is selected from hydrogen, alkyl with 1 to 20 carbon atoms, alkyl with 1 to 20 carbon atoms and containing substituent groups, and alkyl siloxy with 1 to 20 carbon atoms; r4 is a hydrocarbylene group of C3-C10; a and B independently represent a polyether chain, R5 and R5'are independently selected from hydrogen, C1-C24 alkyl or O = CR6, and R6 is selected from hydrogen and C1-C31 alkyl. The synergist has amphiphilic performance balance of carbon dioxide affinity and heavy oil affinity, and the compound has good solubility in carbon dioxide, so that the solubility of carbon dioxide in heavy oil is improved. As a synergist, the compound can strengthen the interaction between thickened oil and carbon dioxide, so that the crude oil extraction efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of crude oil extraction, and in particular to a synergist and a preparation method and application thereof. Background Art

[0002] CCUS is a new development trend of CCS technology, that is, to purify the carbon dioxide emitted in the production process and then put it into the new production process, which can be recycled instead of simply sealed. Among many carbon dioxide utilization projects, carbon dioxide flooding has become one of the important technologies for enhanced oil recovery. The United States is the earliest and most extensive country to apply carbon dioxide flooding experiments. Since 1970, the United States has injected carbon dioxide into oil fields in Texas as a technical means to enhance oil recovery (EOR). The total amount of carbon dioxide injected each year is 20 million to 30 million tons, of which about 3 million tons of carbon dioxide comes from the tail gas of coal gasification plants and fertilizer plants. Most of it is collected from natural carbon dioxide reservoirs and is still in use. The recovery rate of carbon dioxide-EOR miscible flooding is between 4% and 12%.

[0003] Heavy oil is a very important type of crude oil resource, and its production methods are mainly divided into cold production and thermal production. Thermal production methods include steam flooding, steam huff and puff, and steam-assisted gravity drainage (SAGD); while cold production methods include polymer flooding, surfactant flooding, foam flooding, solvent extraction (VAPEX), and microbial flooding. For extra-heavy oil and super-heavy oil with a viscosity greater than 10,000 mPa.s, steam thermal recovery is often used. However, for low-permeability reservoirs, especially low-permeability heavy oil reservoirs, some conventional methods such as steam thermal recovery cannot achieve effective production due to the dual effects of low permeability and high crude oil viscosity. When the oil layer is buried deep, the pay layer is thin, and the reservoir characteristics are poor, it is not suitable for thermal production. The preferred method is carbon dioxide flooding.

[0004] As a traditional method to improve oil recovery, carbon dioxide flooding can effectively improve injection capacity and avoid water sensitivity, and is one of the ways to improve the recovery of low permeability reservoirs. Under a certain temperature and pressure, carbon dioxide can evaporate and extract intermediate molecular weight hydrocarbons in crude oil in a limited amount, so that the injected gas is gradually enriched. Although this limited amount of evaporation is not enough to make carbon dioxide and heavy oil reach multi-stage contact miscibility at the displacement front, it can effectively reduce the interfacial tension between carbon dioxide and crude oil and improve the recovery of immiscible flooding. At present, the technology of carbon dioxide to improve the recovery of heavy oil reservoirs still faces many bottlenecks, especially for deep low permeability heavy oil reservoirs. Therefore, in order to achieve a good oil recovery effect, it is necessary to strengthen the interaction between carbon dioxide and heavy oil through chemical agents, reduce the viscosity of heavy oil, and maximize the contact and start-up of residual oil to improve the oil washing efficiency, and finally achieve the purpose of economically and efficiently improving the recovery of deep low permeability heavy oil reservoirs.

[0005] HDCS is a multi-component composite huff-and-puff technology. It injects three types of plugs, oil-soluble viscosity reducer, carbon dioxide and steam, and then shuts the well. It uses the viscosity reducing effect of chemical agents and carbon dioxide, the expansion effect of carbon dioxide and the heat transfer effect of steam to improve the fluidity of crude oil, expand the scope of influence, reduce the residual oil saturation, and finally open the well for recovery. With the help of this technology, it is possible to exploit ultra-heavy oil reservoirs, and the exploitation effect is also relatively ideal. Li Binfei et al. reported a case of successful implementation of HDCS technology in the Zheng 411 ultra-heavy oil reservoir in Shengli Oilfield. The application of this technology has enabled the ultra-heavy oil reservoir with a viscosity greater than 300,000mPa / s (50℃), a burial depth greater than 1300m and an average oil layer thickness of less than 8m to be mobilized. The SLKF series of oil-soluble viscosity reducers developed by the Petroleum Development Center of Shengli Petroleum Administration Bureau were injected to reduce the viscosity of heavy oil. As of November 2006, 31 wells have been constructed, with a cumulative increase of 13,268 tons of crude oil, and an average increase of 428 tons per well. Zhang Dingyong conducted a numerical simulation analysis of the reservoir for the heavy oil in Guang 9 block of Shengli Oilfield, and studied the mechanism of oil-soluble viscosity reducers, carbon dioxide and steam in the viscosity reduction of heavy oil. The heavy oil reservoir is buried at a depth of 837m, with a formation pressure of 8.46MPa, an effective reservoir thickness of 8-14m, an average porosity of 33%, an average permeability of 5000mD, and a crude oil viscosity of 50℃ is generally 50,000-80,000mPa·s. After laboratory research, the effective radius of viscosity reducers, carbon dioxide and steam for heavy oil viscosity reduction, as well as the relationship between effective viscosity and effective radius were found, and the injection volume of HDCS throughput cycle was optimized. Finally, a plan to switch to HNS throughput after 8 cycles of HDCS throughput was proposed, which optimized and improved the economic effect of the overall plan. The plan was implemented in CNP49 well in Guang 9 block, with 12 production cycles and a cumulative oil production of 2,578 tons.

[0006] Although the above reports have achieved certain results in using oil-soluble viscosity reducers to assist carbon dioxide in the recovery of heavy oil, oil-soluble viscosity reducers are often mixed with low-boiling and low-flash point small molecular compounds such as aromatic hydrocarbons and solvent oils, and have the disadvantages of high concentration, high cost, flammability and explosion, and high operating risks. They also require the use of steam, which is greatly limited in practical applications. The present invention describes such an efficient and safe synergist in heavy oil reservoirs, its preparation method, and its application. Summary of the invention

[0007] In order to overcome the problems of high concentration, high cost, flammability and explosion, and high operation risk in the prior art of chemical-assisted carbon dioxide extraction of heavy oil, a synergist and its preparation method and application are provided. The synergist contains silicon atoms, heteroatoms (nitrogen, oxygen, etc.) or aromatic rings, etc., so that the synergist has a higher boiling point and flash point, and its safety in use can be guaranteed. The synergist has a biphilic performance balance of affinity for carbon dioxide and affinity for heavy oil, and the compound has good solubility in carbon dioxide, which improves the solubility of carbon dioxide in heavy oil. As a synergist, the compound can strengthen the interaction between heavy oil and carbon dioxide, thereby improving the efficiency of crude oil extraction.

[0008] In order to achieve the above-mentioned object, the first aspect of the present invention provides a synergist, the structural formula of the synergist is shown in formula (I);

[0009]

[0010] Among them, R 1 and R 2 Each independently selected from C 1 -C 20 The hydrocarbon group, C 1 -C 20 The alkoxyl group, C 1 -C 20 Hydrocarbylsiloxy groups;

[0011] R 3 Selected from hydrogen, C 1 -C 20 The hydrocarbon group, C 1 -C 20 The alkoxyl group, C 1 -C 20 Hydrocarbylsiloxy; R 4 C 3 -C 10 alkylene;

[0012] A and B each independently represent a polyether chain, R 5 and R 5 ' are each independently selected from hydrogen, C 1 -C 24 Hydrocarbon or O=CR 6 , R 6 Selected from hydrogen, C 1 ~C 31 of hydrocarbon groups.

[0013] The second aspect of the present invention provides a method for preparing the synergist, the method comprising:

[0014] (1) contacting the compound represented by formula (II) with the compound represented by formula (III) in the presence of a catalyst to obtain the compound represented by formula (IV),

[0015] (2) subjecting the compound represented by formula (IV) to catalytic reduction or hydrolysis to remove the protecting group to obtain the compound represented by formula (V);

[0016] (3) a compound represented by formula (V) is reacted with an epoxy compound to obtain a polyether intermediate, and the polyether intermediate is reacted with an optional end-capping agent to obtain the synergist;

[0017]

[0018] Among them, in formula (II), (IV) and (V), R 1 , R 2 , R 3 The definition of is as described in the definition of formula (I);

[0019] In formula (III) and formula (IV), X is R 8 -CN, CN or R 4 'NHR 4 ”, R 8 C 1 -C 7 The alkylene group, R 4 'Selected from C 1 -C 6 The alkylene group, R 4 ” is R 0 CONH, R 0 Selected from hydrogen, C 1 -C 6 The hydrocarbon group;

[0020] In formula (V), R 4 The definition of is as described in formula (I).

[0021] A third aspect of the present invention provides a use of the synergist in heavy oil carbon dioxide flooding or carbon dioxide huff and puff production.

[0022] Through the above technical scheme, the synergist of the present invention contains silicon atoms, which reduces the surface tension of the synergist and improves the surface activity of the synergist. The molecular structure contains heteroatoms such as nitrogen and oxygen and aromatic rings, which can react with heavy oil to form hydrogen bonds and π-π stacking. In particular, nitrogen atoms can react with acidic substances in heavy oil to form acid-base reactions, which together with oxygen atoms are more conducive to adjusting the biphilic performance balance of carbon dioxide and heavy oil. The synergist has a high boiling point and flash point to ensure its safety in use. The synergist has good solubility in carbon dioxide. The synergist is used in heavy oil production, which effectively reduces the interfacial tension between heavy oil and carbon dioxide by 20.9-40.2%. The synergist strengthens the interaction between heavy oil and carbon dioxide, which is conducive to starting heavy oil, improving the efficiency of heavy oil displacement, and has a good application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the infrared spectrum of the synergist I-1-1 prepared in Preparation Example 3-1.

[0024] Figure 2 This is the structural diagram of the TECLIS Scientific Tracker TM high temperature and high pressure interfacial rheometer. 1 is the pressure chamber; 2 is the measuring unit; 3 is the injection pump; 4 is the syringe; 5 is the absorption cell; 6 is the light source; 7 is the camera; and 8 is the distribution box.

[0025] Figure 3 This is the curve of the change of carbon dioxide / crude oil interfacial tension with pressure at 50°C.

[0026] Figure 4 This is the curve of the interfacial tension of enhancer / carbon dioxide / crude oil changing with pressure at 50°C. DETAILED DESCRIPTION

[0027] The endpoints and any values ​​of the ranges disclosed in this article 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 each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0028] The first aspect of the present invention provides a synergist, the structural formula of the synergist is shown in formula (I);

[0029]

[0030] Among them, R 1 and R 2 Each independently selected from C 1 -C 20The hydrocarbon group, C 1 -C 20 The alkoxyl group, C 1 -C 20 Hydrocarbylsiloxy groups;

[0031] R 3 Selected from hydrogen, C 1 -C 20 The hydrocarbon group, C 1 -C 20 The alkoxyl group, C 1 -C 20 Hydrocarbylsiloxy; R 4 C 3 -C 10 alkylene;

[0032] A and B each independently represent a polyether chain, R 5 and R 5 ' are each independently selected from hydrogen, C 1 -C 24 Hydrocarbon or O=CR 6 , R 6 Selected from hydrogen, C 1 ~C 31 The synergist of the present invention contains silicon atoms, which reduces the surface tension of the synergist and improves the surface activity of the synergist. The molecular structure contains heteroatoms such as nitrogen and oxygen and aromatic rings, which can react with heavy oil by hydrogen bonding and π-π stacking. In particular, nitrogen atoms can react with acidic substances in heavy oil by acid-base reaction, which together with oxygen atoms is more conducive to adjusting the balance of the affinity for carbon dioxide and affinity for heavy oil. The synergist has a high boiling point and flash point, which ensures its safety in use.

[0033] In the present invention, C 1 -C 20 The hydrocarbon group, C 1 -C 16 The hydrocarbon group, C 1 -C 10 The hydrocarbon groups include straight chain hydrocarbon groups and branched hydrocarbon groups.

[0034] According to a preferred embodiment of the present invention, in formula (I), R 1 and R 2 Each independently selected from C 1 -C 16 The hydrocarbon group, C 1 -C 12 The alkoxyl group, C 1 -C 12 The hydrocarbylsiloxy group is preferably selected from C 1 -C 10 The hydrocarbon group, C 1 -C10 The alkoxyl group, C 1 -C 10 of hydrocarbon siloxy groups.

[0035] According to a preferred embodiment of the present invention, in formula (I), R 3 Selected from hydrogen, C 1 -C 16 The hydrocarbon group, C 1 -C 16 The alkoxyl group, C 1 -C 20 The hydrocarbylsilyloxy group is preferably selected from hydrogen, C 1 -C 10 The hydrocarbon group, C 1 -C 10 The alkoxyl group, C 1 -C 10 of hydrocarbon siloxy groups.

[0036] According to a preferred embodiment of the present invention, in formula (I), R 4 C 3 -C 8 The alkylene group is preferably selected from C 3 -C 6 of alkylene.

[0037] According to a preferred embodiment of the present invention, in formula (I), R 5 and R 5 ' are each independently selected from hydrogen, C 1 -C 16 Hydrocarbylsiloxy or O=CR 6 , R 6 Selected from C 1 -C 23 Preferably, R 5 and R 5 ' are each independently selected from hydrogen, C 1 -C 12 Hydrocarbylsiloxy or O=CR 6 , R 6 Selected from C 1 -C 17 of hydrocarbon groups.

[0038] In the present invention, the polyether segment is a polyether chain formed by ring-opening polymerization of an epoxy compound. According to a preferred embodiment of the present invention, in formula (I), A is -(CH 2 CH(R a )O) m (CH 2 CH(R a ')O) n (CH 2 CH(Ra ”)O) p -, where R a , R a '、R a " are each independently selected from hydrogen or C 1 -C 5 wherein m, n and p are each independently selected from an integer of 0 to 30, and m, n and p are not 0 at the same time.

[0039] According to a preferred embodiment of the present invention, in formula (I), R a , R a ' and R a " are each independently selected from hydrogen or C 1 -C 4 wherein m, n and p are each independently selected from an integer of 0 to 20, and m, n and p are not 0 at the same time.

[0040] According to a preferred embodiment of the present invention, in formula (I), B is -(CH 2 CH(R b )O) m’ (CH 2 CH(R b ')O) n’ (CH 2 CH(R b ”)O) p’ -, where R b , R b '、R b " are each independently selected from hydrogen or C 1 -C 5 wherein m', n' and p' are each independently selected from integers of 0 to 30, and m', n' and p' are not 0 at the same time.

[0041] According to a preferred embodiment of the present invention, in formula (I), R b , R b ' and R b " are each independently selected from hydrogen or C 1 -C 4 wherein m', n' and p' are each independently selected from integers of 0 to 20, and m', n' and p' are not 0 at the same time.

[0042] According to a preferred embodiment of the present invention, the synergist has a structural formula as shown in formula (I-1);

[0043]

[0044] In formula (I-1), R 1 , R 2 , R 3 , R4 , R 5 , R 5 ' is defined as described in formula (I);

[0045] R a , R a '、R a " are each independently selected from hydrogen or C 1 -C 5 A hydrocarbon group, m, n, p are each independently selected from an integer of 0-30, and m, n, p are not 0 at the same time;

[0046] R b , R b '、R b " are each independently selected from hydrogen or C 1 -C 5 wherein m', n' and p' are independently selected from integers of 0 to 30, and m', n' and p' are not simultaneously 0. The compound represented by formula (I-1) is beneficial for improving the performance of carbon dioxide on heavy oil.

[0047] According to a preferred embodiment of the present invention, R a , R a ' and R a " are each independently selected from hydrogen or C 1 -C 4 wherein m, n and p are each independently selected from an integer of 0 to 20, and m, n and p are not 0 at the same time.

[0048] According to a preferred embodiment of the present invention, R b , R b ' and R b " are each independently selected from hydrogen or C 1 -C 4 wherein m', n' and p' are each independently selected from integers of 0 to 20, and m', n' and p' are not 0 at the same time.

[0049] In the present invention, the synergists having the above characteristics can achieve the purpose of the present invention. The present invention has no particular limitation on the preparation method thereof, as long as the synergist of the present invention can be prepared. The second aspect of the present invention provides a method for preparing the synergist, the method comprising:

[0050] (1) contacting the compound represented by formula (II) with the compound represented by formula (III) in the presence of a catalyst to obtain the compound represented by formula (IV),

[0051] (2) subjecting the compound represented by formula (IV) to catalytic reduction or hydrolysis to remove the protecting group to obtain the compound represented by formula (V);

[0052] (3) the compound represented by formula (V) is reacted with an epoxy compound to obtain a polyether intermediate, and the polyether intermediate is reacted with an optional end-capping agent to obtain the synergist;

[0053]

[0054] Among them, in formula (II), (IV) and (V), R 1 , R 2 , R 3 The definition of is as described in the definition of formula (I);

[0055] In formula (III) and formula (IV), X is R 8 -CN, CN or R 4 'NHR 4 ”, R 8 C 1 -C 7 The alkylene group, R 4 'Selected from C 1 -C 6 The alkylene group, R 4 ” is R 0 CONH, R 0 Selected from hydrogen, C 1 -C 6 The hydrocarbon group;

[0056] In formula (V), R 4 The definition of is as described in formula (I).

[0057] In the present invention, in step (1), the type of the catalyst can be selected from a wide range. According to a preferred embodiment of the present invention, the catalyst is a compound and / or a complex of at least one of platinum, palladium, rhodium, copper, iron, manganese, nickel, cobalt, and tungsten; preferably a compound and / or a complex of at least one of platinum, palladium, and rhodium, more preferably at least one of chloroplatinic acid, triphenylphosphine / chloroplatinic acid, alkali metal carbonate / chloroplatinic acid, and alkyl alkenyl siloxane / chloroplatinic acid.

[0058] In the present invention, triphenylphosphine / chloroplatinic acid is taken as an example, and the catalyst refers to triphenylphosphine, which is a compound with coordination effect, and can improve the catalytic activity of chloroplatinic acid. It has an enhancing effect on the catalytic activity of chloroplatinic acid under experimental conditions; wherein the mass ratio (or molar ratio) of the triphenylphosphine to the chloroplatinic acid is 1:0.1-10.

[0059] In the present invention, the metal carbonate is used to enhance the catalytic activity of chloroplatinic acid. The types of the metal carbonate can be selected from a wide range. According to a preferred embodiment of the present invention, the metal in the metal carbonate is selected from at least one of the alkali metal elements. Preferably, the metal carbonate is selected from at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate.

[0060] In the present invention, in step (1), the contact conditions can be selected in a wide range. According to a preferred embodiment of the present invention, the contact conditions include: a temperature of 30-200°C, preferably 60-140°C; the contact time can be reasonably adjusted according to actual needs, preferably, the time is 2-24h, preferably 3-10h.

[0061] In the present invention, in step (1), the optional range of the amount ratio of the compound represented by formula (II), the compound represented by formula (III), and the catalyst is relatively wide. According to a preferred embodiment of the present invention, the catalyst is calculated based on the amount of metal element, and the molar ratio of the compound represented by formula (II), the compound represented by formula (III), and the catalyst is 1: (1-2): (0.00001-0.001), preferably 1: (1-1.3): (0.000011-0.0001).

[0062] According to a preferred embodiment of the present invention, step (1) is carried out in the presence of a solvent, preferably, the solvent is selected from one or more of benzene, toluene, isopropanol, propanol, ethanol and butanol.

[0063] In the present invention, in step (1), there is no particular limitation on the amount of solvent used. According to a preferred embodiment of the present invention, the amount of solvent used is such that the concentration of the compound represented by formula (II) is 20-90 wt%.

[0064] According to a preferred embodiment of the present invention, step (1) is carried out under an inert gas atmosphere, and the inert gas is selected from one or more of nitrogen and rare gases.

[0065] In the present invention, in step (1), after the reaction is completed, the steps further include water washing, oil-water separation, drying, and distillation to obtain a compound represented by formula (IV); wherein water washing, oil-water separation, drying, and distillation are all conventional separation and purification operations in the art, and there is no particular limitation on the reaction conditions.

[0066] In the present invention, in step (2), the protecting group is removed by catalytic reduction or hydrolysis of the compound represented by formula (IV) to obtain a primary amine intermediate (compound represented by formula (V)). There is no particular limitation on the catalytic reduction conditions, as long as the compound represented by formula (V) can be obtained. According to a preferred embodiment of the present invention, in step (2), the catalytic reduction adopts catalytic hydrogenation reduction, metal hydride catalytic reduction or supported metal catalytic reduction, preferably supported metal catalytic reduction.

[0067] According to a preferred embodiment of the present invention, the supported metal catalytic reduction is carried out in the presence of a supported catalyst, wherein the supported catalyst comprises a carrier and a metal component supported on the carrier, wherein the metal component is selected from at least one of Pd, Pt and Rh, and the carrier is selected from at least one of carbon black, alumina, silica gel, diatomaceous earth and zeolite.

[0068] According to a preferred embodiment of the present invention, based on 100 wt % of the compound represented by formula (IV), the amount of the supported catalyst is 0.01-5 wt %.

[0069] According to a preferred embodiment of the present invention, the catalytic reduction conditions include: a temperature of -10 to 50°C.

[0070] In the present invention, in step (2), in the presence of an alkaline substance, a small molecule alcohol and the compound represented by formula (IV) are subjected to the hydrolysis.

[0071] According to a preferred embodiment of the present invention, the alkaline substance is selected from inorganic bases and / or organic bases, preferably inorganic bases, more preferably NaOH and / or KOH;

[0072] According to a preferred embodiment of the present invention, the small molecule alcohol is a C1-C5 fatty alcohol, preferably at least one of methanol, ethanol, propanol, and isopropanol.

[0073] In step (2), after the reaction is completed, the catalyst is removed by filtration, a solvent is added to dissolve the residue after filtration, the oil and water are separated, and the solvent is removed to obtain a compound as shown in formula (V).

[0074] In the present invention, dichloromethane and / or chloroform are added in step (2) to dissolve the residue after filtration.

[0075] In the present invention, in step (2), oil-water separation and solvent removal are conventional separation and purification operations in the art, and there is no particular limitation on the reaction conditions.

[0076] In the present invention, in step (3), the epoxy compound and the primary amine intermediate (the compound represented by formula (V)) are ring-opening polymerized to form a polyether chain. The present invention has no particular limitation on the type of the epoxy compound. According to a preferred embodiment of the present invention, the epoxy compound is selected from at least one of ethylene oxide, propylene oxide, butylene oxide, pentane oxide, hexane oxide, heptane oxide and octane oxide.

[0077] In the present invention, before step (3), a step of drying the compound represented by formula (V) is also included. In the present invention, there is no particular limitation on the drying conditions, as long as the water in the compound represented by formula (V) is removed. For example, the water can be removed by vacuum drying.

[0078] According to a preferred embodiment of the present invention, the molar ratio of the epoxy compound to the compound represented by formula (V) is 2-60, preferably 2-40.

[0079] In the present invention, the conditions for the first reaction can be selected in a wide range. According to a preferred embodiment of the present invention, the first reaction conditions include: a temperature of 100-200°C, preferably 120-180°C.

[0080] According to a preferred embodiment of the present invention, the first reaction of the compound represented by formula (V) and the epoxy compound is carried out in an inert gas atmosphere. Preferably, the inert gas is selected from one or more of nitrogen and rare gases.

[0081] According to a preferred embodiment of the present invention, in step (3), the end-capping agent is selected from R 5 Y 1 , R 5 'Y 1 , R 5 COY 2 , R 5 'COY 2 , R 5 CO-O-COR 5 or R 5 'CO-O-COR 5 ', where Y 1 is hydroxy or halogen, preferably hydroxy, Cl, Br or I;

[0082] Y 2 is hydroxyl, halogen or C 1 -C 8 The alkoxy group is preferably hydroxyl, Cl, Br or C 1 ~C 5 Alkoxyl groups;

[0083] R 5 and R 5 ' are each independently selected from hydrogen, C1 -C 24 Hydrocarbon or O=CR 6 , R 6 Selected from hydrogen, C 1 ~C 31 of hydrocarbon groups.

[0084] In the present invention, the conditions for the second reaction can be selected in a wide range. According to a preferred embodiment of the present invention, the second reaction conditions include: a temperature of 5-150°C, preferably 10-120°C.

[0085] In the present invention, the conditions of the first reaction can be selected in a wide range. According to a preferred embodiment of the present invention, the molar ratio of the polyether intermediate to the end-capping agent is 1:(2-15), preferably 1:(2-10), wherein the polyether intermediate is calculated based on the amount of hydroxyl groups, and the end-capping agent is calculated based on R 5 and / or R 5 'The amount of substance.

[0086] The third aspect of the present invention provides an application of the synergist in carbon dioxide flooding or carbon dioxide huff-and-puff production of heavy oil. The synergist of the present invention contains silicon atoms, which reduces the surface tension of the synergist and improves the surface and interfacial activity of the synergist. The molecular structure contains heteroatoms such as nitrogen and oxygen and aromatic rings, which can react with heavy oil to form hydrogen bonds and π-π stacking. In particular, nitrogen atoms can react with acidic substances in heavy oil to form acid-base reactions, which together with oxygen atoms are more conducive to regulating the balance of the biphilic properties of carbon dioxide and heavy oil. The synergist has a high boiling point and flash point to ensure its safety in use; the synergist has good solubility in carbon dioxide, and the synergist is used in heavy oil production, which effectively reduces the interfacial tension between heavy oil and carbon dioxide, and the reduction range is 20.9-40.2%. The synergist strengthens the interaction between heavy oil and carbon dioxide, which is conducive to starting heavy oil, improving the efficiency of heavy oil displacement, and has a good application prospect.

[0087] According to a preferred embodiment of the present invention, the synergist is injected together with carbon dioxide or dissolved in carbon dioxide before injection.

[0088] According to a preferred embodiment of the present invention, the injection amount of the synergist is 0.01-5wt% of the carbon dioxide.

[0089] In the present invention, the prepared compound can be analyzed by infrared spectroscopy (scanning range 4000~400cm) using Nicolet-5700 spectrometer of the United States and total reflection infrared spectroscopy (ATR). -1 ), determine the chemical structure of the sample to be tested, so as to achieve infrared characterization of the compound described in the present invention.

[0090] The present invention is described in detail below in conjunction with specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made to the present invention by those skilled in the art based on the contents of the present invention still fall within the scope of protection of the present invention.

[0091] It should also be noted that the various specific technical features described in the following specific embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0092] In addition, the various embodiments of the present invention may be arbitrarily combined as long as they do not violate the concept of the present invention. The technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0093] The raw materials used in the examples and comparative examples, unless otherwise specified, are disclosed in the prior art, for example, they can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0094] The interfacial tension between carbon dioxide and crude oil under formation conditions can better reflect the compatibility of carbon dioxide and crude oil. First, the interfacial tension IFT between carbon dioxide and crude oil under certain temperature and pressure conditions is measured. (CO2 / Oil) Then measure the interfacial tension IFT between carbon dioxide and crude oil after adding the enhancer ( / Chemicals / CO2 / Oil) , calculate the percentage reduction of interfacial tension D according to formula (1).

[0095] D(%)=(IFT (CO2 / Oil) -IFT ( / Chemicals / CO2 / Oil) )×100 / IFT (CO2 / Oil)

[0096] Preparation Example 1 Synthesis of compounds represented by formula (IV), such as formula (IV-1) and formula (IV-2),

[0097]

[0098] Preparation Example 1-1

[0099] Under nitrogen protection, 1 mol of dimethylphenylsilane (in formula (II), R 1 , R 2 , R 3 See Table 1), PPh 3 / H 2 PtCl 6 (molar ratio 1.6:1) isopropanol solution 1.5×10 -5mol (in terms of Pt) and 100 mL of dry benzene were stirred and mixed, heated to 40°C, 1.2 mol of acrylonitrile was added dropwise, and the heat was slowly released. Then the temperature was raised to 100°C and the reaction was continued for 3 hours. After the reaction was completed, the reaction solution was washed with water to remove PPh 3 / H 2 PtCl 6 and isopropanol, separate the layers, extract with benzene three times, combine the organic phases, and add anhydrous MgSO 4 After drying, the solvent benzene was distilled off under reduced pressure to obtain a compound as shown in formula (IV-1). The content of the compound as shown in formula (IV-1) in the product was measured by high performance liquid chromatography HPLC to be 93.2%. The results are shown in Table 1.

[0100] Preparation Example 1-2

[0101] Under nitrogen protection, 1 mol of dimethylphenylsilane (in formula (II), R 1 , R 2 , R 3 See Table 1), H 2 PtCl 6 Isopropanol solution 1.5 × 10 -5 mol (in terms of Pt) and 100 mL of dry benzene were stirred and mixed, heated to 40°C, 1.2 mol of acrylonitrile (containing inhibitor) was added dropwise, and the temperature was raised to 130°C after slow heat release, and the reaction was continued for 7 hours. After the reaction was completed, the reaction solution was washed with water to remove H 2 PtCl 6 and isopropanol, separate the layers, extract with benzene three times, combine the organic phases, and add anhydrous MgSO 4 After drying, the solvent benzene was distilled off under reduced pressure to obtain a compound as shown in formula (IV-1). The content of the compound as shown in formula (IV-1) in the product was measured by high performance liquid chromatography HPLC to be 65.4%. The results are shown in Table 1.

[0102] Preparation Example 1-3

[0103] Under nitrogen protection, 1 mol of dimethylphenylsilane (in formula (II), R 1 , R 2 , R 3 See Table 1), H 2 PtCl 6 / K 2 CO 3 (molar ratio is 1:0.2) isopropanol solution 1.5×10 -5 mol (in terms of Pt) and 100 mL of dry benzene, heated to 40°C, activated for 60 min, then added dropwise 1.2 mol of N-allylacetamide in benzene solution, slowly heated to 130°C, and reacted for 5 h. After the reaction, the reaction solution was washed with water to remove H2 PtCl 6 / K 2 CO 3 and isopropanol, separate the layers, extract with benzene three times, combine the organic phases, and add anhydrous MgSO 4 After drying, the solvent benzene was distilled off under reduced pressure to obtain the compound represented by formula (IV-2). The content of the compound represented by formula (IV-2) in the product was measured by high performance liquid chromatography HPLC to be 91.5%. The results are shown in Table 1.

[0104] Preparation Example 1-4, Preparation Example 1-5, Preparation Example 1-6

[0105] The preparation method of Preparation Example 1-1 is used, except that the raw materials, catalysts, reaction time and temperature are different, as shown in Table 1. The product is tested by high performance liquid chromatography HPLC, and the results are shown in Table 1.

[0106] Table 1

[0107]

[0108] The results in Table 1 show that noble metal platinum and its derivatives are a class of excellent catalysts for hydrosilylation reactions. When the silicon substituent contains a lone pair of electrons, the activity of the reactants is improved; the introduction of triphenylphosphine, potassium carbonate or siloxane ligands with olefin groups into chloroplatinic acid is beneficial to improving the catalytic activity of chloroplatinic acid, increasing the product yield, reducing the reaction temperature and shortening the reaction time.

[0109] Preparation Example 2 Synthesis of the compound represented by formula (V)

[0110]

[0111] Preparation Example 2-1

[0112] In a stainless steel hydrogenation autoclave, 1.0 mol of the compound shown in formula (IV-1) prepared in Preparation Example 1, 240 g of 1,4-dioxane and 0.24 g of 5 wt% Pd-C were sequentially added. After replacing with hydrogen 4 to 5 times, the reactor switch was turned off, stirring was started, hydrogen was passed to 1.2 MPa, and the reaction temperature was controlled to 35°C. When the reaction no longer absorbed hydrogen, the reaction was continued for 2 hours. After cooling, the reaction liquid was filtered to remove the catalyst, and then the solvent was evaporated. The residue was dissolved in dichloromethane, washed with water, and the organic phase was dried and dichloromethane was removed to obtain the intermediate V-1 (in formula (V), R 1 =CH 3 , R 2 =CH 3 , R 3 =C 6 H 5 ), yield 92.2%.

[0113] Preparation Example 2-2

[0114] In a reaction kettle equipped with a mechanical stirrer and a thermometer, 1.0 mol of the compound represented by formula (IV-1) prepared in Preparation Example 2, 1.2 mol of potassium hydroxide, 200 ml of isopropanol and 300 ml of water were added and heated to reflux. After the reaction was completed, the isopropanol was evaporated and the residue was dissolved in dichloromethane. After washing with water, the organic phase was dried and dichloromethane was removed to obtain the intermediate V-1 (in formula (V), R 1 =CH 3 , R 2 =CH 3 , R 3 =C 6 H 5 ), yield 95.9%.

[0115] The results show that using H 2 / Metal catalysts can effectively hydrogenate and reduce nitriles to primary amines, which is not only efficient but also economical; removal of the acylation group can also give primary amines in high yield.

[0116] Preparation Example 2-3

[0117] According to the method of Preparation Example 2-1, except that the compound represented by formula (IV) is the compound prepared in Preparation Example 1-4, and the other conditions are the same as those of Preparation Example 2-1, V-2 (in formula (V), R 1 =(CH 3 ) 3 SiO, R 2 =CH 3 , R 3 =C 6 H 5 )) Yield: 93.8%

[0118] Preparation Example 2-4

[0119] According to the method of Preparation Example 2-1, except that the compound represented by formula (IV) is the compound prepared in Preparation Example 1-5, and the other conditions are the same as those of Preparation Example 2-1, V-3 (in formula (V), R 1 =CH 3 , R 2 =CH 3 , R 3 =(CH 3 ) 3 SiO), with a yield of 91.5%.

[0120] Preparation Example 2-5

[0121] According to the method of Preparation Example 2-1, except that the compound represented by formula (IV) is the compound prepared in Preparation Example 1-6, and the other conditions are the same as those of Preparation Example 2-1, V-4 (in formula (V), R 1 = n- C 3 H 7 , R 2 = n- C 3 H 7 , R 3 = n- C 3 H 7 ), yield 92.1%.

[0122] Preparation Example 3 Preparation of a heavy oil synergist such as that shown in formula (I-1)

[0123]

[0124] Preparation Example 3-1

[0125] ① Polymerization reaction: add 1.0 mol of intermediate V-1 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 85°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3 times, adjust the system reaction temperature to 150°C and slowly introduce 12.3 mol of propylene oxide, control the pressure ≤ 0.40MPa, after the propylene oxide reaction is completed, adjust the temperature to 160°C and slowly introduce 3.1 mol of butylene oxide, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool and neutralize, dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3p+p'=0,R 5 =R 5 '=H), yield 96.7%.

[0126] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.05 mol of isooctanoyl chloride, and continue to reflux for 8 hours after the drop is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% brine, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-1 (in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=iC 7 H 15 CO), the composition is shown in Table 2.

[0127] The infrared detection of the synergist I-1-1 revealed that 2954.3 cm -1 and 2867.2m -1 It is the characteristic peak of CH stretching between methyl and methylene, 1733.2cm -1 is the C=O stretching vibration absorption peak in the ester group, 1456.7 cm -1 The antisymmetric deformation vibration peak of Si-Me is 1237.4 cm -1 It is the Si-Me symmetric deformation vibration peak, 1104.9cm -1 and 1084.1cm -1 Characteristic peaks of COC and Me-Si stretching vibration peaks, 840.1 cm -1 The absorption peaks are 690-740cm caused by the methyl plane rocking vibration and Si-C stretching vibration. -1 It is the absorption peak of the inward and outward swing of the CH plane in the benzene ring, and the CN stretching vibration peak is covered by the strong peak, which proves that the product is the acyl-terminated amino polyether silane I-1-1.

[0128] Preparation Example 3-2

[0129] ① Polymerization reaction: add 1.0 mol of intermediate V-2 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 150°C and slowly introduce 12.3 mol of propylene oxide, control the pressure ≤ 0.40MPa, after the propylene oxide reaction is completed, adjust the temperature to 160°C and slowly introduce 3.1 mol of butylene oxide, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool and neutralize, dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=H), yield 94.1%.

[0130] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.05 mol of isooctanoyl chloride, and continue to reflux for 8 hours after the drop is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% saline, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-2 (in formula (I-1), R 1 =(CH 3 ) 3 SiO, R 2 =CH 3 , R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=iC 7 H15 CO), the composition is shown in Table 2.

[0131] Preparation Example 3-3

[0132] ① Polymerization reaction: add 1.0 mol of intermediate V-3 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 150°C and slowly introduce 12.3 mol of propylene oxide, control the pressure ≤ 0.40MPa, after the propylene oxide reaction is completed, adjust the temperature to 160°C and slowly introduce 3.1 mol of butylene oxide, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool and neutralize, dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =(CH 3 ) 3 SiO,R a =R b =CH 3 , R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=H), yield 93.8%.

[0133] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.05 mol of isooctanoyl chloride, and continue to reflux for 8 hours after the drop is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% saline, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-3 (in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=iC 7 H 15 CO), the composition is shown in Table 2.

[0134] Preparation Example 3-4

[0135] ① Polymerization reaction: add 1.0 mol of intermediate V-1 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 150°C and slowly introduce 12.3 mol of propylene oxide, control the pressure ≤ 0.40MPa, after the propylene oxide reaction is completed, adjust the temperature to 160°C and slowly introduce 3.1 mol of butylene oxide, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool and neutralize, dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 , R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=H), yield 96.7%.

[0136] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.1 mol of benzoyl chloride, and continue to reflux for 5 hours after the dripping is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% brine, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-4 (in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,Ra '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=C 6 H 5 CO), the composition is shown in Table 2.

[0137] Preparation Example 3-5

[0138] ① Polymerization reaction: add 1.0 mol of intermediate V-4 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 150°C and slowly introduce 12.3 mol of propylene oxide, control the pressure ≤ 0.40MPa, after the propylene oxide reaction is completed, adjust the temperature to 160°C and slowly introduce 3.1 mol of butylene oxide, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool and neutralize, dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =nC 3 H 7 ,R 2 =nC 3 H 7 ,R 3 =nC 3 H 7 ,R a =R b =CH 3 , R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=H), yield 95.0%.

[0139] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.1 mol of benzoyl chloride, and continue to reflux for 5 hours after the drop is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% saline, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-5 (in formula (I-1), R 1 =nC 3 H 7 ,R 2 =nC3 H 7 ,R 3 =nC 3 H 7 ,R a =R b =CH 3 , R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=C 6 H 5 CO), the composition is shown in Table 2.

[0140] Preparation Example 3-6

[0141] ① Polymerization reaction: add 1.0 mol of intermediate V-1 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 160°C, slowly introduce 12.3 mol of butylene oxide, control the pressure ≤ 0.40 MPa, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool, neutralize and dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =C 2 H 5 , R a '=C 2 H 5 ,m+m'=12,n+n'=0,p+p'=0,R 5 =R 5 '=H), yield 93.9%.

[0142] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.05 mol of isooctanoyl chloride, and continue to reflux for 8 hours after the drop is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% brine, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-6 (in formula (I-1), R 1 =CH 3 ,R2 =CH 3 ,R 3 =C 6 H 5 ,R a =C 2 H 5 , R a '=C 2 H 5 ,m+m'=12,n+n'=0,p+p'=0,R 5 =R 5 '=iC 7 H 15 CO), the composition is shown in Table 2.

[0143] Preparation Example 3-7

[0144] ① Polymerization reaction: add 1.0 mol of intermediate V-1 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 150°C, slowly introduce 16.4 mol of propylene oxide, control the pressure ≤ 0.40 MPa, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool and neutralize, dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =C 2 H 5 , R a '=CH 3 ,m+m'=16,n+n'=0,p+p'=0,R 5 =R 5 '=H), yield 95.1%.

[0145] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.05 mol of isooctanoyl chloride, and continue to reflux for 8 hours after the drop is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% saline, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-7 (in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R3 =C 6 H 5 ,R a =C 2 H 5 , R a '=CH 3 ,m+m'=16,n+n'=0,p+p'=0,R 5 =R 5 '=iC 7 H 15 CO), the composition is shown in Table 2.

[0146] Preparation Example 3-8

[0147] ① Polymerization reaction: add 1.0 mol of intermediate V-1 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 140°C, slowly introduce 24.3 mol of ethylene oxide, control the pressure ≤ 0.40 MPa, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool and neutralize, dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =H, R a '=H, m+m'=16, n+n'=0, p+p'=0, R 5 =R 5 '=H), yield 97.4%.

[0148] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.05 mol of isooctanoyl chloride, and continue to reflux for 8 hours after the drop is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% brine, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-8 (in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =H, R a'=H, m+m'=16, n+n'=0, p+p'=0, R 5 =R 5 '=iC 7 H 15 CO), the composition is shown in Table 2.

[0149] Preparation Example 3-9

[0150] ① Polymerization reaction: add 1.0 mol of intermediate V-1 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 140°C, slowly introduce 5.05 mol of ethylene oxide, control the pressure ≤ 0.40 MPa, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool, neutralize and dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =H, R a '=H, m+m'=5, n+n'=0, p+p'=0, R 5 =R 5 '=H), yield 96.4%.

[0151] ② Capping reaction: In a dry reaction bottle with a water separator, add 0.5 mol of amino polyether silane, 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene in sequence, heat and reflux until the amount of water brought out reaches more than 90% of the theoretical value, slowly add 1.05 mol of isooctanoyl chloride, and continue to reflux for 8 hours after the drop is completed. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% brine, separate the water layer, wash three times with saturated brine, remove the lower layer of water, and evaporate the solvent benzene under reduced pressure to obtain the synergist I-1-9 (in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =H, R a '=H,m+m'=5,n+n'=0,R 5 =R 5 '=iC 7 H 15 CO), the composition is shown in Table 2.

[0152] Preparation Example 3-10

[0153] Polymerization reaction: add 1.0 mol of intermediate V-1 and 9.0 g of potassium hydroxide to a 2L pressure reactor equipped with a stirring device, heat to 80-90°C, open the vacuum system, dehydrate under high vacuum for 1 hour, then replace with nitrogen 3-4 times, adjust the system reaction temperature to 150°C and slowly introduce 12.3 mol of propylene oxide, control the pressure ≤ 0.40MPa, after the propylene oxide reaction is completed, adjust the temperature to 160°C and slowly introduce 3.1 mol of butylene oxide, after the reaction is completed, cool to 90°C, remove low boiling points in vacuo, cool and neutralize, dehydrate to obtain amino polyether silane ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=H), the yield is 96.7%. The amino polyether silane does not need to be capped, that is, the synergist I-1-10.

[0154] Preparation Example 3-11

[0155] End-capping reaction: 0.5 mol of amino polyether silane (synergist I-1-10) ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5'=H), 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene, heated to reflux until the amount of water taken out reaches more than 90% of the theoretical value, and 2.5 mol of monochloroethane is introduced to continue the reaction for 7 hours. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% brine, separate the water layer, wash it three times with saturated brine, remove the lower water layer, and obtain the synergist I-1-11 ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=C 2 H 5 ), the composition is shown in Table 2.

[0156] Preparation Example 3-12

[0157] End-capping reaction: 0.5 mol of amino polyether silane (synergist I-1-10) ((in formula (I-1), R 1 =CH 3 ,R 2 =CH 3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=H), 2.0 mol of fine-grained potassium hydroxide and 1000 ml of benzene, heated to reflux until the amount of water taken out reaches more than 90% of the theoretical value, and 1.5 mol of trimethylsilyl chloride is introduced to continue the reaction for 5 hours. Cool, pour the reaction solution into water, adjust the pH to neutral with 10% brine, separate the water layer, wash it three times with saturated brine, remove the lower water layer, and obtain the synergist I-1-12 ((in formula (I-1), R 1 =CH 3 ,R 2 =CH3 ,R 3 =C 6 H 5 ,R a =R b =CH 3 ,,R a '=R b '=C 2 H 5 ,m+m'=12,n+n'=3,p+p'=0,R 5 =R 5 '=(CH 3 ) 3 SiO), the composition is shown in Table 2.

[0158] Table 2

[0159] Synergist <![CDATA[R 1 ]]> <![CDATA[R 2 ]]> <![CDATA[R 3 ]]> <![CDATA[R 4 ]]> <![CDATA[R a / R b ]]> <![CDATA[R a ’ / R b ’]]> <![CDATA[R a ” / R b ”]]> I-1-1 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 2 H 5 ]]> - I-1-2 <![CDATA[(CH 3 ) 3 Not]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 2 H 5 ]]> - I-1-3 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[(CH 3 ) 3 Not]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 2 H 5 ]]> - I-1-4 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 2 H 5 ]]> - I-1-5 <![CDATA[ n -C 3 H 7 ]]> <![CDATA[ n -C 3 H 7 ]]> <![CDATA[ n -C 3 H 7 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 2 H 5 ]]> - I-1-6 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[C 2 H 5 ]]> - - I-1-7 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> - - I-1-8 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> H - - I-1-9 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> H - - I-1-10 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 2 H 5 ]]> - I-1-11 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 2 H 5 ]]> - I-1-12 <![CDATA[CH 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 6 H 5 ]]> <![CDATA[(CH 2 ) 3 ]]> <![CDATA[CH 3 ]]> <![CDATA[C 2 H 5 ]]> -

[0160] Table 2 (continued)

[0161]

[0162]

[0163] Preparation Example 3-13

[0164]

[0165] According to the method of Preparation Example 3-1, except that an equal molar amount of tert-butylaniline is used to replace the intermediate V-1, and other conditions remain unchanged, an acyl-terminated amino polyether compound is obtained, as shown in formula (D1).

[0166] Preparation Example 3-14

[0167]

[0168]

[0169] The compound shown in formula (D2) was synthesized according to the existing literature method as follows:

[0170] At room temperature, slowly add propylene bromide (200 mmol) to a vigorously stirred mixture of compound VI-1 (100 mmol), saturated NaOH solution (500 mmol) and tetrabutylammonium bromide (5 mmol), then gradually raise the temperature to 70°C and react for 8 hours. After the reaction is completed, cool to room temperature, filter to obtain a filtrate, wash the filtrate with water, extract with petroleum ether, take the upper organic phase and precipitate with anhydrous MgSO 4 After drying for 24 h, the solvent and unreacted allyl bromide were distilled off under reduced pressure to obtain compound VII-1.

[0171] N 2 Under protection, a certain amount of compound VII-1 (100 mmol) and isopropanol solution of chloroplatinic acid (0.1 mmol) were added to a dry three-necked flask, stirred, heated to 60°C, activated for 30 min, and then compound dimethylphenylsilane II01 (110 mmol) was added dropwise, and the temperature was slowly raised to 120°C and reacted for 8 h. After the reaction was completed, the reaction solution was washed with water to remove chloroplatinic acid and isopropanol, the organic phase was extracted with petroleum ether, and anhydrous MgSO 4 After drying for 12 hours, petroleum ether was removed by distillation under reduced pressure to obtain acyl-terminated polyether silane, as shown in formula (D2).

[0172] Interfacial tension test of embodiments and comparative examples

[0173] With the help of TECLIS high temperature and high pressure interfacial rheometer, the interfacial tension of CO2 / crude oil or CO2 / crude oil / chemical agent is measured by the pendant drop method. TECLIS Scientific Tracker TM The interfacial rheometer consists of a hanging drop chamber, a temperature control system, a gas injection system, a syringe control system, an optical camera system and a software processing system. The upper temperature limit of the instrument is 200°C and the upper pressure limit is 20MPa.

[0174] The interfacial tension test method between carbon dioxide and oil is as follows: 1) After heating the oil, use a syringe to absorb the oil; 2) Place the syringe in a high-temperature and high-pressure hanging drop kettle; 3) Install the high-temperature and high-pressure hanging drop kettle into the Teclis interfacial rheometer and connect it to the carbon dioxide injection system; 4) Adjust the camera so that the syringe needle is in the middle of the screen, and adjust the optical parameters such as image clarity, brightness, and contrast; 5) Replace the air in the hanging drop kettle with carbon dioxide; 6) Turn on the temperature control system to make the temperature in the hanging drop kettle reach the pressure required for the experiment; 6) Inject a certain amount of high-pressure carbon dioxide into the window kettle, and after the temperature and pressure are stable, adjust the syringe motor to slowly press the crude oil into the hanging drop chamber until a pear-shaped oil drop is formed under the needle; 7) Open the software and input the density of crude oil and carbon dioxide under the test conditions; 8) Use the software to shoot the oil drop in real time and calculate the interfacial tension between carbon dioxide and crude oil; 9) Use the same method to measure the interfacial tension at the same temperature and different pressures to obtain the relationship curve between pressure and interfacial tension.

[0175] The interfacial tension between 1# oil (simulated oil, hexadecane), heavy oil (3#, 4#, 5#) and carbon dioxide was measured at 50°C and different pressures (4-20MPa), and compared with that of thin oil (2#). Figure 3 The crude oil characteristics are shown in Table 3. Figure 3It can be seen that the interfacial tension between carbon dioxide and oil decreases with increasing pressure, and the decreasing trend gradually slows down as the pressure further increases. When P = 15.1MPa, the simulated oil hexadecane reaches a single contact miscible phase, and the interfacial tension cannot be measured. Compared with 4# thin oil, at the same pressure, the interfacial tension between 3#, 4#, and 5# heavy oil and carbon dioxide is higher than that of 2# thin oil, and increases with the increase of the viscosity of the heavy oil.

[0176] The 3# heavy oil was selected as the oil phase to carry out the carbon dioxide / heavy oil interfacial tension experiment after adding the synergist, and the effect of the synergist I-1-1 on the carbon dioxide / heavy oil interfacial tension was studied. The added concentration was 1.0wt%, which was calculated as a percentage of the mass of carbon dioxide (based on the mass of carbon dioxide under 50℃ and 15MPa). Figure 4 It can be seen that after adding the synergist, the interfacial tension of 3# heavy oil / carbon dioxide decreased significantly, with the reduction ranging from 27.4% to 31.4%, indicating that the synergist I-1-1 can be distributed at the interface between carbon dioxide and heavy oil, effectively reducing the interfacial tension between carbon dioxide and heavy oil.

[0177] Table 3 Viscosity of heavy oil

[0178]

[0179]

[0180] The temperature was 50°C, the pressure was 15 MPa, and the concentration of the synergist added was 1.0 wt% (as a percentage of the mass of carbon dioxide). The effects of different synergists on the interfacial tension of carbon dioxide / 3# heavy oil were measured, and compared with the interfacial tension of the carbon dioxide / 3# heavy oil system without addition, the interfacial tension reduction percentage D (%) was calculated. The results are shown in Table 4.

[0181] Table 4 Effect of synergists on carbon dioxide / oil interfacial tension

[0182]

[0183]

[0184] As can be seen from the above table, the heavy oil synergist of the present invention has an excellent effect on reducing the interfacial tension of carbon dioxide and heavy oil, with a reduction percentage of 20.9 to 40.2%. The synergist can strengthen the interaction between heavy oil and carbon dioxide and increase the effect of carbon dioxide on heavy oil production. Comparing Example 1 with Comparative Example 1, the introduction of silicon atoms reduces the carbon dioxide / oil interfacial tension by 30.2%, indicating that the introduction of silicon atoms is beneficial to reducing the carbon dioxide / oil interfacial tension and making it easier for carbon dioxide and oil to mix. Comparing Example 1 with Comparative Example 2, the introduction of nitrogen atoms reduces the carbon dioxide / oil interfacial tension by 26.8%, indicating that compared with oxygen atoms, the introduction of nitrogen atoms is more conducive to reducing the carbon dioxide / oil interfacial tension and enhancing the compatibility of carbon dioxide and crude oil.

[0185] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A synergist, characterized in that The structural formula of the synergist is shown in formula (I); Wherein, R1 and R2 are each independently selected from C1-C 20 Hydrocarbon, C1-C 20 The alkoxyl group, C1-C 20 Hydrocarbylsiloxy groups; R3 is selected from hydrogen, C1-C 20 Hydrocarbon, C1-C 20 The alkoxyl group, C1-C 20 Hydrocarbylsiloxy; R4 is C3-C 10 alkylene; A and B each independently represent a polyether chain, R5 and R5' each independently selected from hydrogen, C1-C 24 or O=CR6, R6 is selected from hydrogen, C1-C 31 of hydrocarbon groups.

2. The synergist according to claim 1, wherein In formula (I), R1 and R2 are each independently selected from C1-C 16 Hydrocarbon, C1-C 12 The alkoxyl group, C1-C 12 The hydrocarbylsiloxy group is preferably selected from C1-C 10 Hydrocarbon, C1-C 10 The alkoxyl group, C1-C 10 Hydrocarbylsiloxy groups; and / or In formula (I), R3 is selected from hydrogen, C1-C 16 Hydrocarbon, C1-C 16 The alkoxyl group, C1-C 20 The hydrocarbylsilyloxy group is preferably selected from hydrogen, C1-C 10 Hydrocarbon, C1-C 10 The alkoxyl group, C1-C 10 Hydrocarbylsiloxy groups; and / or In formula (I), R4 is a C3-C8 alkylene group, preferably a C2-C6 alkylene group; and / or In formula (I), R5 and R5' are each independently selected from hydrogen, C1-C 16 Hydrocarbylsilyloxy or O=CR6, R6 is selected from C1-C 23 Preferably, R5 and R5' are each independently selected from hydrogen, C1-C 12 Hydrocarbylsilyloxy or O=CR6, R6 is selected from C1-C 17 of hydrocarbon groups.

3. The synergist according to claim 1 or 2, wherein In formula (I), A is -(CH2CH(R a )O) m (CH2CH(R a ')O) n (CH2CH(R a ”)O) p -, where R a , R a '、R a " are each independently selected from hydrogen or a C1-C5 hydrocarbon group, m, n, and p are each independently selected from an integer of 0-30, and m, n, and p are not 0 at the same time; Preferably, R a , R a ' and R a " are each independently selected from hydrogen or a C1-C4 hydrocarbon group, m, n, p are each independently selected from an integer of 0-20, and m, n, p are not 0 at the same time; and / or In formula (I), B is -(CH2CH(R b )O) m’ (CH2CH(R b ')O) n’ (CH2CH(R b ”)O) p’ -, where R b , R b '、R b " are each independently selected from hydrogen or a C1-C5 hydrocarbon group, m', n', p' are each independently selected from an integer of 0 to 30, and m', n', p' are not 0 at the same time; Preferably, R b , R b ' and R b " are each independently selected from hydrogen or a C1-C4 hydrocarbon group, m', n', p' are each independently selected from an integer of 0-20, and m', n', p' are not 0 at the same time.

4. The synergist according to claim 1 or 2, wherein The structural formula of the synergist is shown in formula (I-1); In formula (I-1), R1, R2, R3, R4, RR5, and R5' are as defined in claim 1 or 2; R a , R a '、R a " are each independently selected from hydrogen or a C1-C5 hydrocarbon group, m, n, and p are each independently selected from an integer of 0-30, and m, n, and p are not 0 at the same time; Preferably, R a , R a ' and R a " are each independently selected from hydrogen or a C1-C4 hydrocarbon group, m, n, p are each independently selected from an integer of 0-20, and m, n, p are not 0 at the same time; and / or R b , R b '、R b " are each independently selected from hydrogen or a C1-C5 hydrocarbon group, m', n', p' are each independently selected from an integer of 0 to 30, and m', n', p' are not 0 at the same time; Preferably, R b , R b ' and R b " are each independently selected from hydrogen or a C1-C4 hydrocarbon group, m', n', p' are each independently selected from an integer of 0-20, and m', n', p' are not 0 at the same time.

5. The method for preparing the synergist according to any one of claims 1 to 4, characterized in that: The method includes: (1) contacting the compound represented by formula (II) with the compound represented by formula (III) in the presence of a catalyst to obtain the compound represented by formula (IV), (2) subjecting the compound represented by formula (IV) to catalytic reduction or hydrolysis to remove the protecting group to obtain the compound represented by formula (V); (3) the compound represented by formula (V) is reacted with an epoxy compound to obtain a polyether intermediate, and the polyether intermediate is reacted with an optional end-capping agent to obtain the synergist; Wherein, in formula (II), (IV) and (V), R1, R2 and R3 are as defined in claim 1 or 2; In formula (III) and formula (IV), X is R8-CN, CN or R4'NHR4", R8 is a C1-C7 alkylene group, R4' is selected from a C1-C6 alkylene group, R4" is R0CO, and R0 is selected from hydrogen and a C1-C6 alkyl group; In formula (V), R4 is as defined in claim 1 or 2.

6. The preparation method according to claim 5, wherein: In step (1), the catalyst is a compound and / or a complex thereof of at least one of platinum, palladium, rhodium, copper, iron, manganese, nickel, cobalt and tungsten; Preferably, it is a compound of at least one of platinum, palladium and rhodium and / or its complex, more preferably at least one of chloroplatinic acid, triphenylphosphine / chloroplatinic acid, alkali metal carbonate / chloroplatinic acid, alkyl alkenyl siloxane / chloroplatinic acid; Preferably, the metal in the metal carbonate is selected from at least one of alkali metal elements; and / or The contact conditions include: temperature of 30-200°C, preferably 60-140°C; time of 2-24h, preferably 3-10h; and / or The catalyst is calculated based on the amount of metal element, and the molar ratio of the compound represented by formula (II), the compound represented by formula (III), and the catalyst is 1: (1-2): (0.00001-0.001), preferably 1: (1-1.3): (0.000011-0.0001).

7. The preparation method according to claim 5, wherein: In step (2), the catalytic reduction adopts catalytic hydrogenation reduction, metal hydride catalytic reduction or supported metal catalytic reduction, preferably supported metal catalytic reduction; Preferably, the supported metal catalytic reduction is carried out in the presence of a supported catalyst, wherein the supported catalyst comprises a carrier and a metal component supported on the carrier, wherein the metal component is selected from at least one of Pd, Pt and Rh, and the carrier is selected from at least one of carbon black, alumina, silica gel, diatomaceous earth and zeolite; and / or Based on 100 wt% of the compound represented by formula (IV), the amount of the supported catalyst is 0.01 to 5 wt%; and / or The catalytic reduction conditions include: a temperature of -10 to 50°C; or In step (2), in the presence of an alkaline substance, a small molecule alcohol and a compound represented by formula (IV) are subjected to the hydrolysis; Preferably, the alkaline substance is selected from inorganic bases and / or organic bases, preferably inorganic bases, more preferably NaOH and / or KOH; Preferably, the small molecule alcohol is a C1-C5 fatty alcohol, preferably at least one of methanol, ethanol, propanol, and isopropanol.

8. The preparation method according to claim 5, wherein In step (3), the epoxy compound is selected from at least one of ethylene oxide, propylene oxide, butylene oxide, pentyl oxide, hexyl oxide, heptane oxide and octane oxide; and / or The molar ratio of the epoxy compound to the compound represented by formula (V) is 2-60, preferably 2-40; and / or The first reaction conditions include: a temperature of 100-200°C, preferably 120-180°C; and / or In step (3), the end-capping agent is selected from R5Y1, R5'Y1, R5COY2, R5'COY2, R5CO-O-COR5 or R5'CO-O-COR5', wherein Y1 is hydroxyl or halogen, preferably hydroxyl, Cl, Br or I; Y2 is hydroxy, halogen or C1-C8 alkoxy, preferably hydroxy, Cl, Br or C1-C5 alkoxy; R5 and R5' are each independently selected from hydrogen, C1-C 24 or O=CR6, R6 is selected from hydrogen, C1~C 31 and / or The second reaction conditions include: a temperature of 5-150°C, preferably 10-120°C; and / or The molar ratio of the polyether intermediate to the end-capping agent is 1:(2-15), preferably 1:(2-10), wherein the polyether intermediate is calculated based on the amount of hydroxyl groups, and the end-capping agent is calculated based on the amount of R5 and / or R5'.

9. Use of the synergist according to any one of claims 1 to 4 in heavy oil carbon dioxide flooding or carbon dioxide huff and puff production.

10. The use according to claim 9, wherein: The synergist is injected together with carbon dioxide or dissolved in carbon dioxide before injection; Preferably, the injection amount of the synergist is 0.01-5wt% of the carbon dioxide.

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