High-temperature-resistant oil displacement agent and preparation method thereof

Abstract

This invention belongs to the field of petroleum extraction technology, specifically relating to a high-temperature resistant oil displacement agent and its preparation method. The method includes: in a nitrogen-filled reactor, under the action of a catalyst, trimethylolpropane allyl ether and 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane undergo an addition reaction; next, a sulfonation reaction occurs with chlorosulfonic acid; and finally, a substitution reaction occurs with dodecylamine to obtain the product oil displacement agent. The molar ratio of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane, chlorosulfonic acid, dodecylamine, and trimethylolpropane allyl ether is 0.8-1.2:1.8-2.4:0.8-1.2:1. The molecular formulas of the main components of the oil displacement agent are as follows: [Insert molecular formula here]. This invention's high-temperature resistant oil displacement agent features low interfacial tension, good temperature resistance, and a high degree of enhanced oil recovery.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, specifically relating to a high-temperature resistant oil displacement agent and its preparation method. Background Technology

[0002] With the increasing scarcity of easily exploitable oil resources, tertiary oil recovery technology has become the main means of improving crude oil recovery. As the core of chemical flooding technology, the performance of the displacement agent directly determines the oil displacement efficiency. Currently, polymer flooding, surfactant flooding, and composite flooding technologies are widely used in oilfields. By increasing the viscosity of the displacement fluid and reducing the oil-water interfacial tension, they effectively improve the oil-water mobility ratio and oil washing efficiency.

[0003] However, with the deepening of exploration and development, oil and gas extraction is facing increasingly harsh high-temperature geological environments, with many reservoirs exceeding 80°C or even 90°C. Under high-temperature conditions, traditional oil displacement agents face severe performance failure problems. Conventional polymer oil displacement agents, such as partially hydrolyzed polyacrylamide, are prone to hydrolysis or degradation of their molecular chains at high temperatures, leading to a significant decrease in solution viscosity and loss of flow control capabilities. Simultaneously, high temperatures disrupt the hydrophilic-lipophilic balance of surfactants, resulting in decreased interfacial activity or even precipitation, failing to effectively reduce oil-water interfacial tension. Single-function oil displacement agents often cannot simultaneously meet the dual requirements of "oil washing" and "oil displacement," and achieving efficient flow control and ultra-low interfacial tension under high-temperature conditions remains a technical bottleneck.

[0004] To address the challenges of high temperatures, researchers have developed novel materials such as hydrophobic associative polymers and temperature- and salt-resistant monomer polymers, or modified traditional surfactants by introducing temperature-resistant groups. However, these methods often suffer from complex synthesis processes and unsatisfactory overall performance. While some systems exhibit temperature resistance under static conditions, their dynamic adsorption in porous media and chemical stability during long-term aging still require improvement.

[0005] Therefore, developing a novel high-temperature resistant oil displacement agent that can maintain long-term stability in high-temperature reservoir environments, possesses excellent viscosity-enhancing and oil-water interfacial tension-reducing capabilities, and has a simple preparation process is of significant practical importance and application value for improving the crude oil recovery rate of complex reservoirs. Summary of the Invention

[0006] This invention addresses the shortcomings of existing technologies by providing a high-temperature resistant oil displacement agent and its preparation method. The high-temperature resistant oil displacement agent of this invention features low interfacial tension, good temperature resistance, and a high degree of enhanced oil recovery.

[0007] The first aspect of this invention provides a method for preparing a high-temperature resistant oil displacement agent, the method comprising: in a nitrogen-filled reactor, under the action of a catalyst, an addition reaction of trimethylolpropane allyl ether and 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane; secondly, a sulfonation reaction with chlorosulfonic acid; and finally, a substitution reaction with dodecylamine to obtain the product oil displacement agent.

[0008] Preferably, in this invention, the molar ratio of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane, chlorosulfonic acid, dodecylamine and trimethylolpropane allyl ether is 0.8-1.2:1.8-2.4:0.8-1.2:1.

[0009] More preferably, the molar ratio of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane, chlorosulfonic acid, dodecylamine and trimethylolpropane allyl ether is 0.9-1.1:2-2.2:0.9-1.1:1.

[0010] Preferably, the catalyst is phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride, and the mass ratio of ruthenium to trimethylolpropane allyl ether is 0.1-0.2:1.

[0011] Preferably, the addition reaction temperature is 100-120℃ and the time is 2-4h.

[0012] Preferably, the sulfonation reaction temperature is 0-10℃ and the time is 0.5-1h.

[0013] Preferably, the substitution reaction temperature is 60-80℃ and the time is 1-2h.

[0014] According to a more specific preferred embodiment, the preparation method of the high-temperature resistant oil displacement agent specifically includes the following steps: (1) Trimethylolpropane allyl ether, 1,1,1,2,2,3,3,4,4,5,5,6,6-tetrafluoro-8-iodooctane and phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride were added sequentially to a high-pressure reactor. The reactor was purged with nitrogen to carry out the addition reaction at a temperature of 100-120℃ for 2-4 hours. The mixture was then cooled and filtered. (2) Chlorosulfonic acid is slowly added dropwise to the filtrate to carry out the sulfonation reaction. The reaction temperature is 0-10℃ and the time is 0.5-1h. (3) Add a mixed solution of isopropanol and water (V:V=1:1), adjust the pH to 8-9, add dodecylamine, and carry out a substitution reaction at a temperature of 60-80℃ for 1-2 hours; distill under reduced pressure to obtain the product oil displacement agent.

[0015] Preferably, the mass ratio of the mixed solution of isopropanol and water to trimethylolpropane allyl ether in step (3) is 6-10:1.

[0016] This invention provides, in two aspects, an oil displacement agent prepared by the above-described preparation method, wherein the molecular formula of the main component of the oil displacement agent is as follows: .

[0017] This invention relates to an anionic surfactant as an oil displacement agent. The lipophilic groups are long-chain alkanes and perfluoroalkanes, while the hydrophilic groups are two sodium sulfates. The two sodium sulfate hydrophilic groups not only provide strong water solubility and negative charge but also effectively expand the molecular area occupied at the interface through electrostatic repulsion. The long-chain alkanes anchor themselves by inserting into crude oil components through the principle of similar compatibility, while the perfluoroalkanes reduce the oil-water interfacial tension to ultra-low levels due to their extremely low surface free energy. Simultaneously, the strong spreading ability of the perfluoro chain combined with the interfacial expansion ability brought by the two hydrophilic groups can efficiently "strip" residual oil films adhering to pores and emulsify them into easily flowing small oil droplets. The sodium sulfate structure endows it with excellent resistance to high-valent cation precipitation, maintaining stability in high-temperature, high-salinity reservoirs. The synergistic effect of the two lipophilic groups allows it to achieve ultra-low interfacial tension at extremely low concentrations, a level difficult for conventional surfactants to achieve. The presence of the fluorocarbon chain significantly improves the adsorption and spreading efficiency of the surfactant on the rock surface, more thoroughly improving rock wettability.

[0018] The beneficial effects and advantages of this invention compared with the prior art are as follows: (1) The oil displacement agent of the present invention has the characteristics of low surface tension, with a surface tension of up to 23 mN / m and an interfacial tension of up to 0.0008 mN / m; (2) The oil displacement agent of the present invention has the characteristic of temperature resistance. After being placed at 180°C for 24 hours, the surface tension and interfacial tension are basically unaffected. (3) The oil displacement agent of this invention has the characteristic of greatly improving the oil recovery rate, which can increase it by 22.4%. Detailed Implementation

[0019] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0020] The technical solution of the present invention will be further described below with reference to specific embodiments: Example 1 Preparation of oil displacement agent (1) Add 0.05 mol of trimethylolpropane allyl ether, 0.04 mol of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane and 0.87 g of phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride to a high-pressure reactor in sequence. Purge the reactor with nitrogen and react at 100°C for 4 h. Cool and filter. (2) Add 0.09 mol of chlorosulfonic acid slowly to the filtrate and react at 0℃ for 1 h; (3) Add 52.2g of a mixed solution of isopropanol and water (V:V=1:1), adjust the pH to 8-9, add 0.04mol of dodecylamine, react at 60℃ for 2h, and distill under reduced pressure to obtain the oil displacement agent.

[0021] Example 2 Preparation of oil displacement agent (1) Add 0.05 mol of trimethylolpropane allyl ether, 0.06 mol of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane and 1.74 g of phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride to a high-pressure reactor in sequence. Purge the reactor with nitrogen and react at 120°C for 2 h. Cool and filter. (2) Add 0.12 mol chlorosulfonic acid dropwise to the filtrate and react at 10°C for 0.5 h; (3) Add 87g of a mixed solution of isopropanol and water (V:V=1:1), adjust the pH to 8-9, add 0.05mol of dodecylamine, react at 80℃ for 1h, and distill under reduced pressure to obtain the oil displacement agent.

[0022] Example 3 Preparation of oil displacement agent (1) Add 0.05 mol of trimethylolpropane allyl ether, 0.045 mol of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane and 1.22 g of phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride to a high-pressure reactor in sequence. Purge the reactor with nitrogen and react at 110 °C for 3 h. Cool and filter. (2) Add 0.1 mol of chlorosulfonic acid slowly to the filtrate and react at 4°C for 1 h; (3) Add 58g of a mixed solution of isopropanol and water (V:V=1:1), adjust the pH to 8-9, add 0.06mol of dodecylamine, react at 70℃ for 1.5h, and distill under reduced pressure to obtain the oil displacement agent.

[0023] Example 4 Preparation of oil displacement agent (1) Add 0.05 mol of trimethylolpropane allyl ether, 0.055 mol of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane and 1.58 g of phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride to a high-pressure reactor in sequence. Purge the reactor with nitrogen and react at 120°C for 3 h. Cool and filter. (2) Add 0.11 mol of chlorosulfonic acid slowly to the filtrate and react at 5°C for 0.6 h; (3) Add 80g of a mixed solution of isopropanol and water (V:V=1:1), adjust the pH to 8-9, add 0.055mol of dodecylamine, react at 70℃ for 2h, and distill under reduced pressure to obtain the oil displacement agent.

[0024] Example 5 Preparation of oil displacement agent (1) Add 0.05 mol of trimethylolpropane allyl ether, 0.05 mol of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane and 1.37 g of phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride to a high-pressure reactor in sequence. Purge the reactor with nitrogen and react at 120°C for 3 h. Cool and filter. (2) Add 0.11 mol of chlorosulfonic acid slowly to the filtrate and react at 5°C for 0.6 h; (3) Add 80g of a mixed solution of isopropanol and water (V:V=1:1), adjust the pH to 8-9, add 0.055mol of dodecylamine, react at 70℃ for 2h, and distill under reduced pressure to obtain the oil displacement agent.

[0025] Example 6: Testing of Surface Tension and Interfacial Tension The oil displacement agent of this invention was prepared into a 1000 mg / L aqueous solution using tap water, and the surface tension γ was measured according to the method in SY / T 5370-2018 "Methods for Determination of Surface and Interfacial Tension". 表1 and interfacial tension γ 界1 The interfacial tension test used dehydrated crude oil (viscosity 25 mPa∙s) from an oil production plant in Shengli Oilfield.

[0026] A comparative experiment was conducted using sulfonates for oil displacement from Shengli Petrochemical Co., Ltd., and the results are shown in Table 1.

[0027] Example 7 Temperature Resistance Test The above solution was placed in a pressure-resistant sealed container and placed in an oven at 180°C for 24 hours. The test in Example 6 was repeated, and the surface tension γ was measured. 表2 and interfacial tension γ 界2 .

[0028] A comparative experiment was conducted using sulfonates for oil displacement from Shengli Petrochemical Co., Ltd., and the results are shown in Table 1.

[0029] Example 8: Determination of Oil Displacement Efficiency The oil displacement agent of this invention was prepared into a 1000 mg / L solution, and the enhanced oil recovery (E) was determined according to SY / T6424-2014 "Performance Test Method for Composite Oil Displacement Systems". R The crude oil and injection water used in the experiment were both taken from an oil production plant in Shengli Oilfield. The crude oil viscosity was 2200 mPa∙s, the injection water salinity was 17890 mg / L, the hardness was 2100 mg / L, and the experimental temperature was 72℃.

[0030] A comparative experiment was conducted using sulfonates for oil displacement from Shengli Petrochemical Co., Ltd., and the results are shown in Table 1.

[0031]

[0032] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-temperature resistant oil displacement agent, characterized in that, The method includes: in a nitrogen-filled reactor, under the action of a catalyst, an addition reaction is carried out between trimethylolpropane allyl ether and 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane; next, a sulfonation reaction is carried out with chlorosulfonic acid; and finally, a substitution reaction is carried out with dodecylamine to obtain the product oil displacement agent. The molar ratio of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane, chlorosulfonic acid, dodecylamine and trimethylolpropane allyl ether is 0.8-1.2:1.8-2.4:0.8-1.2:

1.

2. The preparation method according to claim 1, characterized in that, The molar ratio of 1,1,1,2,2,3,3,4,4,5,5,6,6-tridecylfluoro-8-iodooctane, chlorosulfonic acid, dodecylamine and trimethylolpropane allyl ether is 0.9-1.1:2-2.2:0.9-1.1:

1.

3. The preparation method according to claim 1, characterized in that, The catalyst is phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride, with a mass ratio of 0.1-0.2:1 to trimethylolpropane allyl ether.

4. The preparation method according to claim 1, characterized in that, The addition reaction is carried out at a temperature of 100-120℃ for 2-4 hours.

5. The preparation method according to claim 1, characterized in that, The sulfonation reaction temperature is 0-10℃ and the time is 0.5-1h.

6. The preparation method according to claim 1, characterized in that, The substitution reaction is carried out at a temperature of 60-80℃ for 1-2 hours.

7. The preparation method according to claim 1, characterized in that, The preparation method specifically includes the following steps: (1) Trimethylolpropane allyl ether, 1,1,1,2,2,3,3,4,4,5,5,6,6-tetrafluoro-8-iodooctane and phenylmethylene bis(tricyclohexylphosphine) ruthenium dichloride were added sequentially to a high-pressure reactor. The reactor was purged with nitrogen to carry out the addition reaction at a temperature of 100-120℃ for 2-4 hours. The mixture was then cooled and filtered. (2) Chlorosulfonic acid is slowly added dropwise to the filtrate to carry out the sulfonation reaction. The reaction temperature is 0-10℃ and the time is 0.5-1h. (3) Add a mixed solution of isopropanol and water (V:V=1:1), adjust the pH to 8-9, add dodecylamine, and carry out a substitution reaction at a temperature of 60-80℃ for 1-2 hours; distill under reduced pressure to obtain the product oil displacement agent.

8. The preparation method according to claim 7, characterized in that, The mass ratio of the mixed solution of isopropanol and water to trimethylolpropane allyl ether in step (3) is 6-10:

1.

9. The oil displacement agent prepared by the preparation method according to any one of claims 1-8.

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