A chemical agent composition, its preparation method, and a method for reducing the minimum miscibility pressure of CO2-crude oil.

Abstract

The present application relates to a kind of chemical agent composition and its preparation and its method for reducing CO2-crude oil minimum miscibility pressure.The composition includes sorbitan polyether and triazolyl alkyl ester, the sorbitan polyether is selected from at least one in the structure shown in formula (I), the triazolyl alkyl ester is selected from at least one in the structure shown in formula (II):The chemical agent composition still has excellent solubility and excellent effect of reducing CO2 drive minimum miscibility pressure at high temperature, lower pressure.

Description

Technical Field

[0001] This invention relates to the field of petroleum extraction, and more specifically, to a chemical composition containing sorbitol polyether and triazole alkyl ester, its preparation method, and a method for reducing the minimum miscibility pressure of CO2-crude oil. Background Technology

[0002] CO2 reaches its supercritical state at temperatures above 31.26℃ and pressures above 7.28 MPa. Under most reservoir conditions, CO2 exists in a supercritical state. Supercritical CO2 has excellent solubility for crude oil and is more miscible with it than nitrogen and dry gas, making it an ideal displacement medium. Therefore, CO2 enhanced oil recovery (CO2 EOR) technology plays an increasingly important role in tertiary oil recovery technologies.

[0003] In recent years, calls for greenhouse gas emission reduction have grown louder. Among the emission reduction measures proposed by the International Energy Agency, CCUS (Carbon Capture, Utilization, and Storage) technology accounts for 20%. Currently, over 70% of CO2 captured by CCUS technology is used in CO2 enhanced oil recovery projects. CO2 EOR technology not only improves oilfield recovery but also stores large amounts of CO2, representing a win-win situation for both economic development and environmental protection.

[0004] CO2 flooding is divided into two types: miscible flooding and immiscible flooding. Miscible flooding refers to the process in which CO2 and crude oil in a porous medium dissolve and eliminate the interface to achieve miscibility. Theoretically, the displacement efficiency can reach 100%. Immiscible flooding refers to the process where, under reservoir conditions, CO2 and crude oil, even after diffusion and mass transfer, still cannot completely mix, and an interface remains, resulting in low oil displacement efficiency. The minimum miscibility pressure (MMP) is the minimum pressure required for CO2 and crude oil to achieve multi-stage contact miscibility. When the displacement pressure is higher than the minimum miscibility pressure, miscible displacement can be achieved; when the displacement pressure is lower than the minimum miscibility pressure, only immiscible displacement can occur.

[0005] From the perspective of CO2 displacement principle, miscible displacement has a significantly higher displacement efficiency than immiscible displacement. However, for many reservoirs, the minimum miscibility pressure of CO2 and crude oil is significantly higher than the formation pressure, making miscible displacement impossible and only immiscible displacement is possible. Since the 1980s, petroleum scientists have been studying how to reduce the minimum miscibility pressure of CO2 and crude oil, and have reported some methods and chemical agents for reducing the minimum miscibility pressure of CO2 displacement. They are mainly divided into the following categories: ① coolant (US4513821); ② low molecular weight hydrocarbons (US4678036); ③ fatty alcohols (US4899817); ④ tall oil (US4736793); ⑤ surfactants (Adv Mater Res (Durnten-Zurich, Switzerland). 2011, 239; Petrol. Sci. Technol. 2017, 35(4), 345.).

[0006] The inventor's previous invention patents (CN202010619765.9, CN113881417A) disclosed a chemical composition containing sorbitol polyether carboxylate, its preparation method, and a method for reducing the minimum miscibility pressure in CO2 flooding. The amphiphilicity of sorbitol polyether carboxylate and the polyether additive in CO2 / crude oil effectively reduced the minimum miscibility pressure. However, at high temperatures (T≥100℃), the chemical composition exhibits high dissolution pressure in CO2, resulting in poor effectiveness in reducing the minimum miscibility pressure in high-temperature, low-fracture-pressure CO2 flooding reservoirs. Summary of the Invention

[0007] To address the problem that most domestic oil reservoirs have high minimum miscibility pressures between CO2 and crude oil, making CO2 miscible displacement impossible and resulting in low oil displacement efficiency, this invention designs a triazole alkyl ester with excellent affinity for CO2 and combines it with dehydrated sorbitol polyether to provide a chemical composition and its application method that still has excellent solubility and excellent miscibility pressure reduction effect at high temperature and low pressure.

[0008] One objective of this invention is to provide a chemical composition comprising sorbitol polyether and triazole alkyl ester, wherein the molar ratio of sorbitol polyether to triazole alkyl ester is 1:(0.05-20), preferably 1:(0.1-10).

[0009] The dehydrated sorbitol polyether is selected from at least one of the structures shown in formula (I):

[0010]

[0011] In equation (I), R1, R2, and R3 are independently (CH2). eH and e are any integers from 0 to 4; a1, a2, a3, a4 are the number of polyether groups with substituent R1, b1, b2, b3, b4 are the number of polyether groups with substituent R2, and c1, c2, c3, c4 are the number of polyether groups with substituent R3; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4 are all independent integers from 0 to 50, and a 1+ a 2+ a 3+ a 4+ b 1+ b 2+ b 3+ b 4+ c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 Hydrocarbon group or substituted hydrocarbon group.

[0012] The triazole alkyl ester is selected from at least one of the structures shown in formula (II):

[0013]

[0014] In formula (II), R4, R5, and R6 are independently hydrogen atoms, C1 to C2 atoms. 50 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are either hydrogen atoms independently or COOR7 and not all of them are hydrogen atoms at the same time, and R7 is C1 to C2. 50 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 20.

[0015] According to a preferred embodiment of the present invention, R1, R2, and R3 are each (CH2). e H and e are any integers from 0 to 4, and R1, R2, and R3 are not simultaneously hydrogen atoms; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, and c4 are independently any integers from 0 to 50, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 50The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, Y3 are independently hydrogen atoms or ester groups, and not all of them are hydrogen atoms at the same time, R7 is C1 to C2. 50 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 20;

[0016] Preferably, in the above embodiments, R1, R2, and R3 are independently (CH2). e H and e are any integers from 0 to 4, and R1, R2, and R3 are not simultaneously hydrogen atoms; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, and c4 are independently any integers from 0 to 30, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 30 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1 to C2. 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

[0017] According to a preferred embodiment of the present invention, R1, R2, and R3 are each (CH2). e H and e are any integers from 0 to 4, and R1, R2, and R3 contain at least two different groups; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, and c4 are independently any integers from 0 to 50, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 50 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1 to C2. 50The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 20;

[0018] Preferably, in the above embodiments, R1, R2, and R3 are independently (CH2). e H and e are any integers from 0 to 4, and R1, R2, and R3 contain at least two different groups; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, and c4 are independently any integers from 0 to 30, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 30 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1 to C2. 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

[0019] According to a preferred embodiment of the present invention, R1, R2, and R3 are each (CH2). e H and e are any integers from 1 to 4; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4 are all independent integers from 0 to 50, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 50 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1 to C2. 50 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 20.

[0020] Preferably, in the above embodiments, R1, R2, and R3 are independently (CH2). eH and e are any integers from 1 to 4; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4 are all independent integers from 0 to 30, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 30 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1 to C2. 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

[0021] According to a preferred embodiment of the present invention, R1, R2, and R3 are each (CH2). e H and e are any integers from 1 to 3; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4 are all independent integers from 0 to 50, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 50 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1 to C2. 50 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 20;

[0022] Preferably, in the above embodiments, R1, R2, and R3 are independently (CH2). e H and e are any integers from 1 to 3; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4 are all independent integers from 0 to 30, and a 1+ a 2+ a 3+ a4>0, b1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 30 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1 to C2. 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

[0023] The chemical composition can be directly dissolved in supercritical CO2 and injected into the reservoir, promoting the interaction between CO2 and crude oil under formation conditions and reducing the minimum miscibility pressure between the two.

[0024] A second objective of this invention is to provide a method for preparing the chemical composition, comprising mixing the dehydrated sorbitol polyether and triazole alkyl ester.

[0025] The molar ratio of sorbitol polyether to triazolyl ester is 1:(0.05-20), preferably 1:(0.1-10).

[0026] The dehydrated sorbitol polyether can be prepared by the following steps:

[0027] ① Sorbitol and dehydrating agent A are heated to dehydrate and etherify, yielding dehydrated sorbitol;

[0028] ② In the presence of base B, dehydrated sorbitol is reacted with an epoxy compound to obtain a dehydrated sorbitol polyether compound in which X1, X2, X3, and X4 are all hydrogen atoms;

[0029] Optionally, ③ in the presence of base C, the dehydrated sorbitol polyether compound obtained in step ② undergoes a condensation reaction with R8Cl to obtain dehydrated sorbitol polyethers in which X1, X2, X3, and X4 are hydrocarbon groups or substituted hydrocarbon groups;

[0030] Among them, R8 is C1 to C 50 Hydrocarbon group or substituted hydrocarbon group.

[0031] In the above preparation steps of dehydrated sorbitol polyether,

[0032] In step ①, the reaction temperature is 140-180℃; the dehydrating agent A is selected from at least one of P2O5, p-toluenesulfonic acid, and phosphoric acid, and the amount of dehydrating agent used is preferably 0.5-2wt% of sorbitol.

[0033] In step ②, the reaction temperature is 100–140℃ and the reaction pressure is 0.10–0.40 MPa; the epoxy compound is selected from at least one of ethylene oxide, propylene oxide, and butane oxide; the base B is selected from at least one of sodium carbonate, sodium hydroxide, and potassium hydroxide, and the molar ratio of base B to sorbitol is preferably 0.1–2.0.

[0034] In step ③, the alkali C is at least one of sodium hydroxide and potassium hydroxide, and the molar ratio of alkali C to the dehydrated sorbitol polyether compound is preferably 1.0 to 2.0.

[0035] The triazole alkyl ester can be obtained by the following steps:

[0036] ①'Amine compounds or amino ester compounds react with NaNO2 in hydrochloric acid solution to give diazonium salts;

[0037] ②' Diazonium salts react with NaN3 in a weakly alkaline solution to form azide compounds;

[0038] ③'Alkyne esters react with azide compounds in the presence of a copper catalyst and a reducing agent to yield triazole alkyl esters.

[0039] In the above preparation steps of triazolyl esters,

[0040] In step ①', the reaction temperature is -8 to -3℃; the concentration of hydrochloric acid solution is 2 to 6 mol / L; the molar ratio of NaNO2 to amine compound or amine ester compound is 1 to 1.2; urea is added to quench the reaction after it is completed, and the molar ratio of urea to amine compound or amine ester compound is preferably 0.1 to 0.12.

[0041] In step ②', the reaction temperature is -5 to 0℃; the weak base solution is selected from at least one of the aqueous solutions of sodium acetate, sodium propionate or sodium butyrate, and the concentration of the weak base solution is preferably 1.5 to 2.5 mol / L; the molar ratio of NaN3 to the amine compound or amine ester compound is 1 to 1.2.

[0042] In step ③', the reaction temperature is room temperature; the copper catalyst is selected from CuI, CuBr, and CuSO4·5H2O, and the molar ratio of the copper catalyst to the alkynyl ester compound is preferably 0.05-0.1; the reducing agent is sodium ascorbate, and the molar ratio of the reducing agent to the alkynyl ester compound is preferably 0.1-0.2; the molar ratio of the alkynyl ester compound to the azide compound is preferably 0.8-1.2.

[0043] The third objective of this invention is to provide a method for reducing the minimum miscibility pressure of CO2-crude oil, which includes dissolving the chemical agent composition in liquid or supercritical CO2 and then injecting it into the formation.

[0044] The amount of the chemical agent composition used is 0.1% to 5% of the mass of CO2 under the injection pressure, more preferably 0.5% to 2%.

[0045] The method is applicable to formation reservoirs with temperatures ranging from 50 to 200°C and injection temperatures ranging from 0 to 100°C.

[0046] In the chemical composition of this invention, sorbitol polyether exhibits amphiphilicity to both CO2 and crude oil, effectively reducing the interfacial tension between CO2 and crude oil, thereby lowering their minimum miscibility pressure; triazole alkyl ester, possessing ester groups and a triazole ring associated with CO2, exhibits excellent solubility in CO2. The composition of sorbitol polyether and triazole alkyl ester demonstrates high solubility in CO2 and effectively reduces the minimum miscibility pressure for CO2 displacement over a wide temperature and pressure range.

[0047] The chemical composition and method for reducing the minimum miscibility pressure of CO2-crude oil of this invention can be used, but are not limited to, CO2 flooding reservoirs with formation temperatures of 50–200°C and injection temperatures of 0–100°C, helping to achieve miscible flooding in CO2 immiscible flooding reservoirs and improving oil recovery. "CO2 + chemical agent" flooding experiments were conducted by adding 0.1–5% of the chemical composition based on the mass percentage of CO2 at the injection pressure. Thin-tube experiments showed that after adding this chemical composition, the minimum miscibility pressure of CO2-crude oil was reduced by up to 29.5%, and the recovery rate was increased by up to 25.98% compared to pure CO2 flooding. Attached Figure Description

[0048] Figure 1 This is a diagram of the apparatus for a thin tube experiment.

[0049] Figure 1 1 is a high-pressure plunger pump, 2 is a back pressure valve, 3 is a receiving bottle, 4 is a buffer bottle, 5 is an HPLC pump, 6 is a high-pressure pump, 7 is a data acquisition system, 8 is an oven, and 9 is a capillary tube model.

[0050] Among them, high-pressure plunger pump 1 is a CO2 injection system, HPLC pump 5 is a chemical reagent injection system, high-pressure pump 6 is an oil injection system, and oven 8 is a temperature control system. Detailed Implementation

[0051] To enable those skilled in the art to better understand the present invention and to better demonstrate its beneficial effects, the present invention will be further elaborated with reference to specific examples. It should be noted that the following embodiments are only for further illustration of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made to the present invention by those skilled in the art based on the content of the present invention still fall within the scope of protection of the present invention.

[0052] The raw materials used in the specific embodiments of this invention are commercially available or custom-made.

[0053]

Example 1

[0054] (a) Preparation of dehydrated sorbitol polyether:

[0055] ① Add 183g (1mol) of sorbitol and 2g of P2O5 to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 160℃ and react for 1.5h to obtain dehydrated sorbitol.

[0056] ② Add 6.0 g of sodium hydroxide to the above reaction vessel to remove air from the reaction flask. Under N2 protection, heat the system to 120°C, and slowly introduce 232 g (4 mol) of propylene oxide, controlling the pressure to ≤0.20 MPa. After the reaction is complete, cool to 90°C, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 380.3 g of sorbitol polyoxypropylene (n=4) ether, with a yield of 95.8%.

[0057] (b) Preparation of triazolyl esters:

[0058] ① Leucine ethyl ester hydrochloride (195g, 1mol) was dissolved in 6M HCl (200mL), cooled and stirred in an ice-salt bath (-5 to -3℃) to obtain solution A. NaNO2 (83g, 1.2mol) was dissolved in 50mL of water and cooled in an ice bath to obtain solution B. Solution B was slowly added dropwise to solution A, maintaining the system temperature at -5 to -3℃. After the addition was complete, the reaction was allowed to proceed for 5 minutes, and then urea (7.2g, 0.12mol) was added to quench the excess NaNO2, yielding diazo solution C.

[0059] ② Dissolve NaN3 (65g, 1mol) and sodium acetate (33g, 0.4mol) in 200mL of water, cool in an ice bath to obtain solution D. Slowly add diazo solution C dropwise to solution D. After the addition is complete, continue the reaction for 1 hour. Extract with ethyl acetate, and dry the organic phase with anhydrous Na2SO4. Filter and concentrate to obtain 174.8g of azide compound E, yield 94.1%.

[0060] ③ Methyl propargyl ester (42 g, 0.5 mol), the azide compound obtained in step ② (92.5 g, 0.5 mol), CuSO4·5H2O (6.25 g, 0.025 mol), and Na Ascorbate (9.9 g, 0.05 mol) were dissolved in a 500 mL reaction flask. The mixture was purged with N2 three times. Under N2 protection, 100 mL of methanol and 100 mL of water were added. The mixture was stirred at room temperature for 12 hours. Most of the solvent was removed under reduced pressure, and the mixture was extracted with CH2Cl2. The organic phase was dried over anhydrous Na2SO4. After filtration and concentration, 128.3 g of triazolyl ester was obtained, with a yield of 95.3%.

[0061] (c) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazole alkyl ester:

[0062] At room temperature, the sorbitol polyoxypropylene (n=4) ether prepared in step (a) and the triazole alkyl ester prepared in step (b) are mixed at a molar ratio of 1:0.5 and stirred for 3 hours to obtain the chemical composition S01 containing sorbitol polyether and triazole alkyl ester.

[0063]

Example 2

[0064] (a) Preparation of dehydrated sorbitol polyether:

[0065] ① Add 183g (1mol) of sorbitol and 2g of P2O5 to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 160℃ and react for 1.5h to obtain dehydrated sorbitol.

[0066] ② Add 6.0 g of sodium hydroxide to the above reaction vessel to remove air from the reaction flask. Under N2 protection, heat the system to 120°C, and slowly introduce 232 g (4 mol) of propylene oxide, controlling the pressure to ≤0.20 MPa. After the reaction is complete, cool to 90°C, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 380.3 g of sorbitol polyoxypropylene (n=4) ether, with a yield of 95.8%.

[0067] ③ Add 198.5 g (0.5 mol) of dehydrated sorbitol polyoxypropylene (n=4) ether, 102.4 g (0.5 mol) of dodecane chloride, and 20.0 g of sodium hydroxide to a dry reaction vessel, and remove oxygen under vacuum. Under N2 protection, heat the system to 150 °C and react for 8 h. Wash with water and dry to obtain 256.9 g of dehydrated sorbitol polyoxypropylene (n=4) lauryl ether, yield 94.5%.

[0068] (b) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazolyl ester:

[0069] At room temperature, the sorbitol polyoxypropylene (n=4) lauryl ether prepared in step (a) and the triazole alkyl ester prepared in step (b) of [Example 1] are mixed at a molar ratio of 1:2 and stirred for 3 hours to obtain the chemical composition SO2 containing sorbitol polyether and triazole alkyl ester.

[0070]

Example 3

[0071] (a) Preparation of dehydrated sorbitol polyether:

[0072] ① Add 183g (1mol) of sorbitol and 2g of P2O5 to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 160℃ and react for 1.5h to obtain dehydrated sorbitol.

[0073] ② Add 7.0 g of potassium hydroxide to the above reaction vessel and remove air from the reaction flask under vacuum. Under N2 protection, heat the system to 120°C and slowly introduce 464 g (8 mol) of propylene oxide, controlling the pressure to ≤0.20 MPa. After the reaction is complete, cool to 90°C, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 604.4 g of sorbitol polyoxypropylene (n=8) ether, with a yield of 96.1%.

[0074] (b) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazolyl ester:

[0075] At room temperature, the sorbitol polyoxypropylene (n=8) ether prepared in step (a) and the triazole alkyl ester prepared in step (b) of [Example 1] are mixed at a molar ratio of 1:3 and stirred for 3 hours to obtain the chemical composition S03 containing sorbitol polyether and triazole alkyl ester.

[0076]

Example 4

[0077] (a) Preparation of dehydrated sorbitol polyether:

[0078] ① Add 183g (1mol) of sorbitol and 1g of p-toluenesulfonic acid to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 120℃ and react for 15min to obtain dehydrated sorbitol.

[0079] ② Add 7.2g of sodium hydroxide to the above reaction vessel and remove air from the reaction flask under vacuum. Under N2 protection, heat the system to 120℃, and slowly introduce 432g (6mol) of epoxide, controlling the pressure to ≤0.20MPa. After the reaction is complete, cool to 90℃, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 568.9g of dehydrated sorbitol polyoxybutylene (n=6) ether, with a yield of 95.3%.

[0080] (b) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazolyl ester:

[0081] At room temperature, the sorbitol polyoxybutylene (n=6) ether prepared in step (a) and the triazole alkyl ester prepared in step (b) of [Example 1] are mixed at a molar ratio of 1:3 and stirred for 3 hours to obtain the chemical composition S04 containing sorbitol polyether and triazole alkyl ester.

[0082]

Example 5

[0083] (a) Preparation of dehydrated sorbitol polyether:

[0084] ① Add 183g (1mol) of sorbitol and 2g of P2O5 to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 160℃ and react for 1.5h to obtain dehydrated sorbitol.

[0085] ② Add 8.4g of potassium hydroxide to the above reaction vessel and remove air from the reaction vessel under vacuum. Under N2 protection, heat the system to 110℃, and slowly introduce 176g (4mol) of ethylene oxide, controlling the pressure ≤0.10MPa. After the ethylene oxide reaction is complete, raise the temperature to 120℃, and slowly introduce 232g (4mol) of propylene oxide, controlling the pressure ≤0.20MPa. After the reaction is complete, cool to 90℃, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 552.9g of dehydrated sorbitol polyoxyethylene (n=4) polyoxypropylene (n=4) ether, with a yield of 96.5%.

[0086] (b) Preparation of triazolyl esters:

[0087] ① L-Serine ethyl ester hydrochloride (169 g, 1 mol) was dissolved in 6 M HCl (200 mL), cooled and stirred in an ice-salt bath (-5 to -3 °C) to obtain solution A. NaNO2 (83 g, 1.2 mol) was dissolved in 50 mL of water and cooled in an ice bath to obtain solution B. Solution B was slowly added dropwise to solution A, maintaining the system temperature at -5 to -3 °C. After the addition was complete, the reaction was allowed to proceed for 5 min, and then urea (7.2 g, 0.12 mol) was added to quench the excess NaNO2, yielding diazo solution C.

[0088] ② Dissolve NaN3 (65 g, 1 mol) and sodium acetate (33 g, 0.4 mol) in 200 mL of water, cool in an ice bath to obtain solution D. Slowly add diazo solution C dropwise to solution D. After the addition is complete, continue the reaction for 1 hour. Extract with ethyl acetate, and dry the organic phase with anhydrous Na2SO4. Filter and concentrate to obtain 146.7 g of azide compound E, yield 92.3%.

[0089] ③ Ethyl propargylate (49 g, 0.5 mol), the azide compound obtained in step ② (79.5 g, 0.5 mol), CuSO4·5H2O (6.25 g, 0.025 mol), and Na Ascorbate (9.9 g, 0.05 mol) were dissolved in a 500 mL reaction flask. The mixture was purged with N2 three times. Under N2 protection, 100 mL of methanol and 100 mL of water were added. The mixture was stirred at room temperature for 12 hours. Most of the solvent was removed under reduced pressure, and the mixture was extracted with CH2Cl2. The organic phase was dried over anhydrous Na2SO4. After filtration and concentration, 123.5 g of triazolyl ester was obtained, with a yield of 96.1%.

[0090] (c) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazole alkyl ester:

[0091] At room temperature, the sorbitol polyoxyethylene (n=4) polyoxypropylene (n=4) ether prepared in step (a) and the triazole alkyl ester prepared in step (b) are mixed at a molar ratio of 1:8 and stirred for 3 hours to obtain the chemical composition S05 containing sorbitol polyether and triazole alkyl ester.

[0092]

Example 6

[0093] (a) Preparation of dehydrated sorbitol polyether:

[0094] ① Add 183g (1mol) of sorbitol and 2g of P2O5 to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 160℃ and react for 1.5h to obtain dehydrated sorbitol.

[0095] ② Add 6.0 g of sodium hydroxide to the above reaction vessel and remove the air from the reaction vessel under vacuum. Under N2 protection, heat the system to 110°C and slowly introduce 132 g (3 mol) of ethylene oxide, controlling the pressure ≤0.10 MPa. After the ethylene oxide reaction is complete, raise the temperature to 120°C and slowly introduce 360 ​​g (5 mol) of butylene oxide, controlling the pressure ≤0.20 MPa. After the reaction is complete, cool down to 90°C, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 633.3 g of sorbitol polyoxyethylene (n=3) polyoxybutylene (n=5) ether, with a yield of 96.4%. (b) Preparation of chemical composition containing sorbitol polyether and triazolyl ester:

[0096] At room temperature, the sorbitol polyoxyethylene (n=3) polyoxybutene (n=5) ether prepared in step (a) and the triazole alkyl ester prepared in step (b) of [Example 5] are mixed at a molar ratio of 1:12 and stirred for 3 hours to obtain the chemical composition S06 containing sorbitol polyether and triazole alkyl ester.

[0097]

Example 7

[0098] (a) Preparation of dehydrated sorbitol polyether:

[0099] ① Add 183g (1mol) of sorbitol and 2g of P2O5 to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 160℃ and react for 1.5h to obtain dehydrated sorbitol.

[0100] ② Add 7.0 g of potassium hydroxide to the above reaction vessel and remove the air from the reaction flask under vacuum. Under N2 protection, heat the system to 110°C and slowly introduce 176 g (4 mol) of ethylene oxide, controlling the pressure ≤0.10 MPa. After the ethylene oxide reaction is complete, raise the temperature to 120°C and slowly introduce 232 g (4 mol) of propylene oxide, controlling the pressure ≤0.20 MPa. After the reaction is complete, cool down to 90°C, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 551.2 g of dehydrated sorbitol polyoxyethylene (n=4) polyoxypropylene (n=4) ether, with a yield of 96.2%. (b) Preparation of triazolyl esters:

[0101] ① Leucine ethyl ester hydrochloride (195g, 1mol) was dissolved in 6M HCl (200mL), cooled and stirred in an ice-salt bath (-5 to -3℃) to obtain solution A. NaNO2 (83g, 1.2mol) was dissolved in 50mL of water and cooled in an ice bath to obtain solution B. Solution B was slowly added dropwise to solution A, maintaining the system temperature at -5 to -3℃. After the addition was complete, the reaction was allowed to proceed for 5 minutes, and then urea (7.2g, 0.12mol) was added to quench the excess NaNO2, yielding diazo solution C.

[0102] ② Dissolve NaN3 (65g, 1mol) and sodium acetate (33g, 0.4mol) in 200mL of water, cool in an ice bath to obtain solution D. Slowly add diazo solution C dropwise to solution D. After the addition is complete, continue the reaction for 1 hour. Extract with ethyl acetate, and dry the organic phase with anhydrous Na2SO4. Filter and concentrate to obtain 174.8g of azide compound E, yield 94.1%.

[0103] ③ Dissolve 70 g (0.5 mol) of ethyl 2-hexynate, 92.5 g (0.5 mol) of the azide compound obtained in step ②, 6.25 g (0.025 mol) of CuSO4·5H2O, and 9.9 g (0.05 mol) of Na Ascorbate in a 500 mL reaction flask. Replace the nitrogen three times with N2. Under N2 protection, add 100 mL of methanol and 100 mL of water. Stir at room temperature for 12 hours. Remove most of the solvent under reduced pressure, extract with CH2Cl2, and dry the organic phase with anhydrous Na2SO4. Filter and concentrate to obtain 155.7 g of triazolyl ester, yield 95.8%.

[0104] (c) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazole alkyl ester:

[0105] At room temperature, the polyoxyethylene (n=4) polyoxypropylene (n=4) ether prepared in step (a) and the triazole alkyl ester prepared in step (b) are mixed in a molar ratio of 1:6 and stirred for 3 hours to obtain the chemical composition S07 containing dehydrated sorbitol polyether and triazole alkyl ester.

[0106]

Example 8

[0107] (a) Preparation of dehydrated sorbitol polyether:

[0108] ① Add 183g (1mol) of sorbitol and 1g of p-toluenesulfonic acid to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 150℃ and react for 15min to obtain dehydrated sorbitol.

[0109] ② Add 6.0 g of sodium hydroxide to the above reaction vessel and remove air from the reaction vessel under vacuum. Under N2 protection, heat the system to 120°C, and slowly introduce 348 g (6 mol) of propylene oxide, controlling the pressure to ≤0.20 MPa. After the propylene oxide reaction is complete, slowly introduce 288 g (4 mol) of butane oxide, controlling the pressure to ≤0.20 MPa. After the reaction is complete, cool to 90°C, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 764.1 g of dehydrated sorbitol polyoxypropylene (n=6) polyoxybutene (n=4) ether, with a yield of 95.4%.

[0110] (b) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazolyl ester:

[0111] At room temperature, the sorbitol polyoxypropylene (n=6) polyoxybutene (n=4) ether prepared in step (a) and the triazole alkyl ester prepared in step (b) of [Example 7] are mixed at a molar ratio of 1:16 and stirred for 3 hours to obtain the chemical composition S08 containing sorbitol polyether and triazole alkyl ester.

[0112]

Example 9

[0113] (a) Preparation of dehydrated sorbitol polyether:

[0114] ① Add 183g (1mol) of sorbitol and 1g of p-toluenesulfonic acid to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 150℃ and react for 15min to obtain dehydrated sorbitol.

[0115] ② Add 7.0 g of potassium hydroxide to the above reaction vessel and remove air from the reaction flask under vacuum. Under N2 protection, heat the system to 110°C, and slowly introduce 352 g (8 mol) of ethylene oxide, controlling the pressure to ≤0.10 MPa. After the reaction is complete, cool to 90°C, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 497.3 g of dehydrated sorbitol polyoxyethylene (n=8) ether, with a yield of 96.2%.

[0116] ③ Add 258.5 g (0.5 mol) of dehydrated sorbitol polyoxyethylene (n=8) ether, 116.4 g (0.5 mol) tetradecyl chloride, and 30.0 g potassium hydroxide to a dry reaction vessel, and remove oxygen under vacuum. Under N2 protection, heat the system to 150 °C and react for 10 h. Wash with water and dry to obtain 321.7 g of dehydrated sorbitol polyoxyethylene (n=8) tetradecyl ether, with a yield of 93.7%.

[0117] (b) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazolyl ester:

[0118] At room temperature, the sorbitol polyoxyethylene (n=8) tetradecane ether prepared in step (a) and the triazolyl ester prepared in step (b) of [Example 7] are mixed at a molar ratio of 1:10 and stirred for 3 hours to obtain the chemical composition S09 containing sorbitol polyether and triazolyl ester.

[0119]

Example 10

[0120] (a) Preparation of dehydrated sorbitol polyether:

[0121] ① Add 183g (1mol) of sorbitol and 1g of p-toluenesulfonic acid to the reaction vessel, and remove oxygen from the reaction vessel under vacuum. Under N2 protection, heat to 150℃ and react for 15min to obtain dehydrated sorbitol.

[0122] ② Add 8.0 g of sodium hydroxide to the above reaction vessel and remove air from the reaction vessel under vacuum. Under N2 protection, heat the system to 110°C, and slowly introduce 176 g (4 mol) of ethylene oxide, controlling the pressure ≤0.10 MPa. After the ethylene oxide reaction is complete, raise the temperature to 120°C, and slowly introduce 232 g (4 mol) of propylene oxide, controlling the pressure ≤0.20 MPa. After the propylene oxide reaction is complete, slowly introduce 288 g (4 mol) of butane oxide, controlling the pressure ≤0.20 MPa. After the reaction is complete, cool to 90°C, remove low-boiling substances under reduced pressure, and after cooling, neutralize and dehydrate to obtain 817.9 g of dehydrated sorbitol polyoxyethylene (n=4) polyoxypropylene (n=4) polyoxybutene (n=4) ether, with a yield of 95.0%.

[0123] (b) Preparation of chemical compositions containing dehydrated sorbitol polyether and triazolyl ester:

[0124] At room temperature, the sorbitol polyoxyethylene (n=4), polyoxypropylene (n=4), and polyoxybutene (n=4) ethers prepared in step (a) and the triazole alkyl esters prepared in step (b) of [Example 7] are mixed at a molar ratio of 1:15 and stirred for 3 hours to obtain the chemical composition S10 containing sorbitol polyether and triazole alkyl esters.

[0125]

Comparative Example 1

[0126] At room temperature, the dehydrated sorbitol polyoxypropylene (n=4) ether and isomeric tridecyl alcohol polyoxypropylene (n=3) ether prepared in Example 1 (preparation method is the same as in Example 1 of invention patent CN202010619765.9) were mixed and stirred for 3 hours at a molar ratio of 1:0.5 to obtain chemical composition S11.

[0127]

Comparative Example 2

[0128] [Example 11] Determination of Minimum Miscibility Pressure

[0129] This invention employs a capillary tube experiment to study the effect of the aforementioned chemical agent system on reducing the minimum miscibility pressure of CO2-crude oil. Referring to standard "SY / T 6573-2003", the following method was used... Figure 1 A capillary apparatus was used to conduct capillary experiments. Capillary parameters are shown in Table 1. The experimental steps are as follows: 1. After cleaning the capillary, saturate it with crude oil at the required temperature and pressure. 2. At the experimental temperature, pressure, and constant injection rate, inject CO2 to displace the crude oil. Measure the produced oil volume every time 0.1 pore volume is injected, and record the upstream and downstream pressures and pump readings. 3. Stop displacing when the accumulated CO2 entering the pump exceeds 1.5 times the pore volume. 4. Calculate the oil displacement efficiency of injecting 1.2 times the pore volume of CO2. Record the average upstream and downstream pressures of the capillary as the displacement pressure. 5. Select 4–6 pressure points and repeat steps 1–3 for capillary displacement experiments. First, conduct the experiment at the original formation pressure. Based on the miscibility and degree of miscibility, use a method of successively approximating the minimum pressure to determine other displacement pressures. Then, conduct displacement experiments at 2–3 pressure points each in the miscible and immiscible sections. 6. Plot the relationship curve between displacement pressure and oil displacement efficiency. The intersection of the immiscible and miscible sections is the minimum miscibility pressure (MMP).

[0130] Table 1 Basic Parameters of Capillary Tubes

[0131]

[0132] The crude oil used in the thin tube experiment was supplied by Shengli Oilfield, and the experimental temperature was 120℃.

[0133] First, the minimum miscibility pressure of pure CO2 flooding was determined using a capillary tube experiment. Then, a chemical reagent composition of a certain concentration was injected using an HPLC pump, mixed with supercritical CO2, and then injected into the capillary tube. The minimum miscibility pressure of "CO2 + chemical reagent" flooding was determined using the same method. The test results are shown in Table 2.

[0134] Table 2 shows the effect of chemical agent compositions on reducing minimum miscibility pressure in CO2 flooding.

[0135]

[0136] [Example 12] Determination of Oil Displacement Efficiency

[0137] Referring to standard "SY / T 6573-2003", indoor oil displacement experiments were conducted using the aforementioned thin tube. At 120℃ and 22.0 MPa pressure, pure "CO2 displacement" and "CO2 + chemical agent" displacement experiments were carried out respectively, and the oil displacement efficiency after injecting 1.2 PVCO2 was recorded. The experimental results are shown in Table 3.

[0138] Table 3 Results of Indoor Oil Displacement Test

[0139]

[0140] This invention not only helps CO2 immiscible flooding reservoirs achieve miscible flooding and improve oil recovery, but also solves the problem of co-injection of CO2 and chemical agents, with low chemical agent adsorption loss.

Claims

1. A chemical composition comprising sorbitol polyether and triazole alkyl ester, wherein the molar ratio of sorbitol polyether to triazole alkyl ester is 1: (0.05~20). The dehydrated sorbitol polyether is selected from at least one of the structures shown in formula (I): （I）， In equation (I), R1, R2, and R3 are independently (CH2). e H and e are any integers from 1 to 4; a1, a2, a3, a4 are the number of polyether groups with substituent R1, b1, b2, b3, b4 are the number of polyether groups with substituent R2, and c1, c2, c3, c4 are the number of polyether groups with substituent R3; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4 are all independent integers from 0 to 50, and a 1+ a 2+ a 3+ a 4+ b 1+ b 2+ b 3+ b 4+ c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 Hydrocarbon group or substituted hydrocarbon group; The triazole alkyl ester is selected from at least one of the structures shown in formula (II): (II), In formula (II), R4, R5, and R6 are independently hydrogen atoms and C1~C1 atoms. 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, Y3 are either hydrogen atoms independently or COOR7 and not all of them are hydrogen atoms at the same time, and R7 is C1~C 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are any integers from 0 to 10, or the triazolyl ester is a compound with the following structure: or .

2. The chemical composition according to claim 1, characterized in that: The molar ratio of dehydrated sorbitol polyether to triazolyl ester is 1:(0.1~10).

3. The chemical composition according to claim 1, characterized in that: R1, R2, and R3 are (CH2) independently. e H and e are any integers from 1 to 4, and R1, R2, and R3 are not simultaneously hydrogen atoms; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, and c4 are independently any integers from 0 to 50, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, Y3 are independently hydrogen atoms or ester groups, and not all of them are hydrogen atoms at the same time, R7 is C1~C 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

4. The chemical composition according to claim 3, characterized in that: R1, R2, and R3 are (CH2) independently. e H and e are any integers from 1 to 4, and R1, R2, and R3 are not simultaneously hydrogen atoms; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, and c4 are independently any integers from 0 to 30, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 30 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1~C 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

5. The chemical composition according to claim 1, characterized in that: R1, R2, and R3 are (CH2) independently. e H and e are any integers from 1 to 4, and R1, R2, and R3 contain at least two different groups; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, and c4 are independently any integers from 0 to 50, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1~C 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

6. The chemical composition according to claim 5, characterized in that: R1, R2, and R3 are (CH2) independently. e H and e are any integers from 1 to 4, and R1, R2, and R3 contain at least two different groups; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, and c4 are independently any integers from 0 to 30, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 30 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1~C 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

7. The chemical composition according to claim 1, characterized in that: R1, R2, and R3 are (CH2) independently. e H and e are any integers from 1 to 4; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4 are all independent integers from 0 to 50, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 50 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1~C 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

8. The chemical composition according to claim 7, characterized in that: R1, R2, and R3 are independently (CH2). e H and e are any integers from 1 to 4; a1, a2, a3, a4, b1, b2, b3, b4, c1, c2, c3, c4 are all independent integers from 0 to 30, and a 1+ a 2+ a 3+ a4>0, b 1+ b 2+ b 3+ b4>0, c 1+ c 2+ c 3+ c4>0; X1, X2, X3, X4 are independent hydrogen atoms, C1~C 30 The hydrocarbon group or substituted hydrocarbon group; R4, R5, R6 are independently hydrogen atoms or C1~C 30 The hydrocarbon group or substituted hydrocarbon group; Y1, Y2, and Y3 are independently hydrogen atoms, the ester group COOR7 and not simultaneously hydrogen atoms, and R7 is C1~C 30 The hydrocarbon group or substituted hydrocarbon group; n1, n2, n3 are independent integers from 0 to 10.

9. A method for preparing a chemical composition according to any one of claims 1 to 8, comprising mixing the dehydrated sorbitol polyether and triazole alkyl ester.

10. The preparation method according to claim 9, characterized in that... The dehydrated sorbitol polyether was prepared by the following steps: ① Sorbitol and dehydrating agent A are heated to dehydrate and etherify, to obtain dehydrated sorbitol, wherein the dehydrating agent A is selected from at least one of P2O5, p-toluenesulfonic acid, and phosphoric acid; ② In the presence of base B, dehydrated sorbitol is reacted with an epoxy compound to obtain a dehydrated sorbitol polyether compound in which X1, X2, X3, and X4 are all hydrogen atoms, wherein base B is selected from at least one of sodium carbonate, sodium hydroxide, and potassium hydroxide; Optionally, ③ in the presence of base C, the dehydrated sorbitol polyether compound obtained in step ② undergoes a condensation reaction with R8Cl to obtain the dehydrated sorbitol polyether, wherein base C is at least one of sodium hydroxide and potassium hydroxide; Where R8 is C1~C 50 Hydrocarbon group or substituted hydrocarbon group.

11. The preparation method according to claim 10, characterized in that: In step ①, the reaction temperature is 140~180℃; the amount of dehydrating agent used is 0.5~2wt% of sorbitol; In step ②, the reaction temperature is 100~140℃ and the reaction pressure is 0.10~0.40 MPa; the epoxy compound is selected from at least one of ethylene oxide, propylene oxide, and butane oxide; the molar ratio of base B to sorbitol is 0.1~2.

0. In step ③, the alkali C is at least one of sodium hydroxide and potassium hydroxide, and the molar ratio of alkali C to the dehydrated sorbitol polyether compound is 1.0~2.

0.

12. The preparation method according to claim 9, characterized in that... The triazole alkyl ester is prepared by the following steps: ①'Amine compounds or amino ester compounds react with NaNO2 in hydrochloric acid solution to give diazonium salts; ②' Diazonium salts react with NaN3 in a weakly alkaline solution to form azide compounds; ③'Alkyne esters react with azide compounds in the presence of a copper catalyst and a reducing agent to yield triazole alkyl esters.

13. The preparation method according to claim 12, characterized in that: In step ①, the reaction temperature is -8 to -3. o C; The concentration of hydrochloric acid solution is 2~6 mol / L; the molar ratio of NaNO2 to amine compound or amine ester compound is 1~1.2; after the reaction is completed, urea is added to quench the reaction, and the molar ratio of urea to amine compound or amine ester compound is 0.1~0.12; In step ②', the reaction temperature is -5~0℃. o C; The weak base solution is selected from at least one of the aqueous solutions of sodium acetate, sodium propionate, or sodium butyrate, and the concentration of the weak base solution is 1.5~2.5 mol / L; the molar ratio of NaN3 to the amine compound or amine ester compound is 1~1.2; In step ③', the reaction temperature is room temperature; the copper catalyst is selected from at least one of CuI, CuBr, and CuSO4·5H2O, and the molar ratio of the copper catalyst to the alkynyl ester compound is 0.05~0.1; the reducing agent is sodium ascorbate, and the molar ratio of the reducing agent to the alkynyl ester compound is 0.1~0.

2.

14. A method for reducing the minimum miscibility pressure of CO2-crude oil, comprising dissolving the chemical composition of any one of claims 1 to 8 in liquid or supercritical CO2 and then injecting it together into the formation.

15. The method for reducing the minimum miscibility pressure of CO2-crude oil according to claim 14, characterized in that: The amount of the chemical agent composition used is 0.1-5% of the mass of CO2 at the injection pressure; and / or, The formation reservoir temperature is 50~200℃, and the injection temperature is 0~100℃.

16. The method for reducing the minimum miscibility pressure of CO2-crude oil according to claim 15, characterized in that: The amount of the chemical agent composition used is 0.5% to 2% of the mass of CO2 under the injection pressure.

Images