Environment-friendly oil cleaning liquid and preparation method and application thereof

Abstract

The present application belongs to the technical field of oil exploitation, and particularly relates to an environment-friendly oil cleaning liquid, a preparation method and application thereof. The environment-friendly oil cleaning liquid is composed of one or more of the following substances:, and the preparation method specifically comprises the following steps: adding 1-aminoethyl-2-heptadecyl imidazoline and isopropyl alcohol / water mixed solvent (V:V=1:1) into a reactor, stirring uniformly, adding sodium chloroethanesulfonate, and keeping warm to react; adding 3-chloro-2-hydroxypropyl phosphate sodium, keeping warm to react, and obtaining the environment-friendly oil cleaning liquid. The molar ratio of sodium chloroethanesulfonate, 3-chloro-2-hydroxypropyl phosphate sodium and 1-aminoethyl-2-heptadecyl imidazoline is 0.1-1:0.1-1:1. The oil cleaning liquid has the advantages of simple preparation, environmental protection, and high oil washing efficiency.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology, specifically relating to an environmentally friendly cleaning fluid, its preparation method, and its application. Background Technology

[0002] During oil and gas field development, as extraction progresses, complex oil-water emulsion systems form within the reservoir. On one hand, during drilling and cementing, the residue of oil-based drilling fluid in the wellbore and near-wellbore zone forms a dense oil film, severely affecting the cementing quality of subsequent cement sheaths and effective communication with the oil and gas layers. On the other hand, during tertiary oil recovery, the surface of reservoir rock pores after long-term waterflooding adsorbs a large amount of crude oil. Especially in complex reservoir conditions such as high temperature and high salinity, the washing efficiency of traditional oil displacement systems decreases significantly, resulting in a large amount of residual oil remaining in the rock pores and being difficult to wash off, severely restricting the improvement of crude oil recovery.

[0003] To address the oil removal needs in the aforementioned reservoirs, existing technologies primarily employ chemical cleaning methods. For example, during cementing operations, a separatory fluid containing surfactants is used to flush the wellbore to remove oil-based drilling fluid. In terms of enhanced oil recovery, polymer or surfactant-based flooding systems are injected to increase the viscosity of the injected water and reduce the oil-water interfacial tension, thereby improving oil washing capabilities. However, existing oil removal technologies still have several shortcomings: First, while some traditional oil removal agents have significant oil-washing effects, they are highly toxic and have poor biodegradability, posing potential threats to the reservoir's ecological environment and groundwater, resulting in high environmental risks. Second, for deep reservoirs with high temperatures and high salinity, existing chemical flooding agents are prone to molecular chain breakage or cross-linking network destruction, leading to a significant decrease in viscosity and failing to meet the oil removal requirements under harsh reservoir conditions. Furthermore, some oil removal systems, when cleaning oil-based drilling fluids, often rely on a simple combination of physical flushing and chemical cleaning, which is insufficient for deep and rapid removal of tightly adhered oil contaminants and can easily trigger complex downhole situations such as shale collapse.

[0004] Therefore, developing an environmentally friendly cleaning fluid that can adapt to different reservoir conditions, is environmentally friendly, and can efficiently remove oil from reservoir rocks and wellbore has become an urgent technical problem to be solved in this field. Summary of the Invention

[0005] This invention addresses the shortcomings of the prior art by providing an environmentally friendly oil-cleansing solution, its preparation method, and its application. The oil-cleansing solution of this invention has the advantages of simple and environmentally friendly preparation and high oil-cleansing efficiency.

[0006] The first objective of this invention discloses an environmentally friendly oil-removing liquid, which is composed of one or more of the following substances: , ,

[0007] The second objective of this invention is to provide a method for preparing the aforementioned environmentally friendly oil-removing liquid, the method specifically comprising the following steps: S1. Add 1-aminoethyl-2-heptadecylimidazoline and isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir evenly, add sodium chloroethanesulfonate, keep the reaction at the temperature, and control the pH value to 7-8. S2. Add sodium 3-chloro-2-hydroxypropyl phosphate, maintain the temperature for reaction, and control the pH value to 7-8 to obtain an environmentally friendly clear oil solution.

[0008] In this invention, the molar ratio of sodium chloroethanesulfonate, sodium 3-chloro-2-hydroxypropyl phosphate, and 1-aminoethyl-2-heptadecylimidazoline is further 0.1-1:0.1-1:1.

[0009] Furthermore, the structural formula of the 1-aminoethyl-2-heptadecylimidazoline is as follows:

[0010] The preparation method is referenced from Yan Jizhong, Shangguan Chengye, et al., Synthesis of 1-aminoethyl-2-heptadecylimidazoline, Guangdong Chemical Industry, 1997, 22-23.

[0011] Furthermore, the structural formula of the sodium 3-chloro-2-hydroxypropyl phosphate is as follows:

[0012] The preparation method is described in "Surfactant Synthesis Technology", by Lü Tong, Chemical Industry Press, p. 202.

[0013] Furthermore, the mass ratio of the isopropanol / water mixed solvent (V:V=1:1) to 1-aminoethyl-2-heptadecylimidazoline in S1 is 10-12:1.

[0014] Furthermore, the heat preservation reaction described in S1 refers to a temperature of 50-60℃, a time of 1-2 hours, and a pH of 7-8.

[0015] Furthermore, the heat preservation reaction described in S2 refers to a temperature of 60-70℃, a time of 2-4 hours, and a pH of 7-8.

[0016] Furthermore, the pH value of 7-8 is controlled using an aqueous solution of sodium hydroxide or potassium hydroxide.

[0017] This invention relates to an environmentally friendly oil-removing solution, a multi-component composite cleaning agent containing isopropanol, sulfonates, and phosphate esters. Isopropanol, a polar solvent, can penetrate into crude oil, reducing its viscosity. Simultaneously, it helps water and oil to mutually solubilize, initially breaking down large crude oil clumps into smaller droplets. Isopropanol's small molecular weight and strong penetrating power allow it to carry sulfonates and phosphate esters to quickly penetrate into the gaps between the crude oil layer and the surface of metal or rock strata, severing the crude oil's adhesion. When sulfonates encounter oil droplets initially dispersed by isopropanol, they surround the droplets, forming an oil-in-water emulsion. This stabilizes the crude oil, which would otherwise aggregate, preventing it from re-adhering to the cleaned surface. Sulfonates can adsorb onto solid surfaces, altering the surface wettability (from oleophilic to hydrophilic), thus causing the oil film to be "rolled up" and detached.

[0018] Phosphate esters have excellent resistance to hard water. When encountering water with high mineralization or oil-bearing water, they can prevent the precipitation of calcium sulfonate salts, ensuring that the cleaning fluid remains active throughout the process. When phosphate esters are combined with sulfonates, they produce a synergistic effect, which can reduce the oil-water interfacial tension more significantly than either one alone. When the interfacial tension drops to an extremely low level, the cleaning fluid can spontaneously "displace" crude oil from the rock formation or metal surface. Phosphate esters have a corrosion inhibitory effect, forming a protective film on the metal surface during cleaning, reducing corrosion to the equipment.

[0019] The beneficial effects and advantages of this invention compared with the prior art are as follows: (1) The preparation process of the environmentally friendly clear oil liquid of the present invention is a one-pot method. No post-treatment is required after preparation. The preparation process is relatively environmentally friendly. All components in the present invention can be degraded by microorganisms and will not produce secondary pollution. (2) The environmentally friendly oil-washing liquid of the present invention has a high oil washing rate, which can reach up to 99.5%. Detailed Implementation

[0020] The technical solution of the present invention will be further described below with reference to specific embodiments: Example 1 S1: Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 176 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir well, add 5 mmol of sodium chloroethanesulfonate, keep the reaction at 50°C for 1.5 h, and maintain the pH at 7-8 with sodium hydroxide solution. S2. Add 50 mmol of sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at 60°C for 2 hours, and maintain the pH at 7-8 with sodium hydroxide solution to obtain an environmentally friendly clear oil solution.

[0021] Example 2 S1: Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 188 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir well, add 10 mmol of sodium chloroethanesulfonate, keep the reaction at 50°C for 2 h, and maintain the pH at 7-8 with sodium hydroxide solution. S2. Add 50 mmol of sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at 60°C for 2 hours, and maintain the pH at 7-8 with sodium hydroxide solution to obtain an environmentally friendly clear oil solution.

[0022] Example 3 S1: Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 200 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir evenly, add 20 mmol of sodium chloroethanesulfonate, keep the reaction at 50°C for 1.5 h, and maintain the pH at 7-8 with sodium hydroxide solution. S2. Add 40 mmol of sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at 65°C for 3 hours, and maintain the pH at 7-8 with sodium hydroxide solution to obtain an environmentally friendly clear oil solution.

[0023] Example 4 S1: Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 200 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir well, add 30 mmol of sodium chloroethanesulfonate, keep the reaction at 55°C for 1.5 h, and maintain the pH at 7-8 with sodium hydroxide solution. S2. Add 30 mmol of sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at 65°C for 4 hours, and maintain the pH at 7-8 with sodium hydroxide solution to obtain an environmentally friendly clear oil solution.

[0024] Example 5 S1: Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 200 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir well, add 40 mmol of sodium chloroethanesulfonate, keep the reaction at 55°C for 2 h, and maintain the pH at 7-8 with sodium hydroxide solution. S2. Add 20 mmol of sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at 65°C for 4 hours, and maintain the pH at 7-8 with sodium hydroxide solution to obtain an environmentally friendly clear oil solution.

[0025] Example 6 S1: Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 211 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir well, add 50 mmol of sodium chloroethanesulfonate, keep the reaction at 60°C for 1 h, and maintain the pH at 7-8 with potassium hydroxide solution. S2. Add 5 mmol of sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at 70°C for 3 hours, and maintain the pH at 7-8 with potassium hydroxide solution to obtain an environmentally friendly clear oil solution.

[0026] Example 7 S1: Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 211 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir until uniform, add 50 mmol of sodium chloroethanesulfonate, keep the reaction at 60°C for 1.5 h, and maintain the pH at 7-8 with potassium hydroxide solution. S2. Add 50 mmol of sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at 70°C for 2 hours, and maintain the pH at 7-8 with potassium hydroxide solution to obtain an environmentally friendly clear oil solution.

[0027] Comparative Example 1 Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 211 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir well, and adjust the pH to 7-8 with potassium hydroxide solution.

[0028] Comparative Example 2 Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 211 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir well, add 50 mmol of sodium chloroethanesulfonate, keep the reaction at 60℃ for 1.5 h, and maintain the pH at 7-8 with potassium hydroxide solution.

[0029] Comparative Example 3 Add 50 mmol of 1-aminoethyl-2-heptadecylimidazoline and 211 g of isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir well, add 50 mmol of sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at 70℃ for 2 h, and maintain the pH at 7-8 with potassium hydroxide solution.

[0030] Comparative Example 4 Sodium dodecylbenzenesulfonate was diluted to a concentration of 1 wt% during testing.

[0031] Test Example 1: Oil Washing Efficiency Test The test method refers to Q / SHCG 11-2017 "Technical Requirements for Oil Layer Cleaning Agents", and the specific steps are as follows: 1. Prepare artificial sludge oil Mix 83g crude oil, 12g petroleum asphalt, and 5g paraffin wax in the specified proportions, and heat until homogeneous.

[0032] 2. Preparation of oil sands Weigh 4.0g of artificial oil stain into a 250mL beaker, add 10mL of 120# solvent oil to dissolve the artificial oil stain, stir with a glass rod, add 170g of quartz sand to the solution, stir evenly to fully mix the sand and oil stain, heat and stir in a water bath at (80~90)℃ for more than 0.5h, evaporate the solvent oil to obtain oil sand, the mass fraction of oil in this oil sand is K=2.3%.

[0033] 3. Determination of wash oil ratio 1) Prepare the oil-removing solution of the present invention into an aqueous solution with a mass fraction of 10%. Weigh 6.0g of oil sand into a 50mL beaker, add 20mL of the present invention diluted 10 times, place the beaker in a 60℃ constant temperature water bath, remove the beaker every 15min and gently rotate it for 10s, then place it back in the water bath, and leave it for a total of 1h. After that, remove the beaker, gently shake it, and use tweezers to hold cotton and dab away the oil stains on the liquid surface and the beaker wall. Be careful not to let the cotton touch the oil sand, and carefully pour off the washing solution.

[0034] 2) Rinse the beaker with distilled water to remove any remaining cleaning solution until the rinse solution is clear.

[0035] 3) Place the rinsed beaker containing oil sand into an oven at (105±2)℃ and dry for 4 hours. Remove it and place it in a desiccator to cool to room temperature.

[0036] 4) Take a small amount of 120# solvent oil and rinse the dried oil sand several times. Collect the rinsed 120# solvent oil in a 50mL colorimetric tube.

[0037] 5) Then pour the oil sand into a funnel containing filter paper, and rinse with 120# solvent oil until the color of the filtered solvent oil matches that of the 120# solvent oil. Collect the rinsed solvent oil into the aforementioned 50mL colorimetric tube and dilute to the mark. If the volume exceeds 50mL, dilute to 100mL.

[0038] 6) Determine the oil content of the above solution according to the provisions of 5.4 in SY / T 5329—2012.

[0039] The wash-oil ratio is calculated using the following formula: X= × 100% In the formula: X—Wash rate, % K—Oil sands oil content (mass fraction), % W0—The mass of the oil sand, in grams; W1—Residual oil content in the oil sand inside the colorimetric tube, in g.

[0040] Comparative examples 1, 2, 3, and 4 were tested using the same method, and the results are shown in Table 1.

[0041] Test Example 2: Evaluation of Corrosion Inhibition Performance The corrosion inhibition performance of the oil-removing solution of the present invention was tested and evaluated in the laboratory. The water sample was injected water from a block of Shengli Oilfield, and the test concentration was 1 wt%. The evaluation method referred to GB / T 18175-2014 "Determination of Corrosion Inhibition Performance of Water Treatment Agents". Comparative Examples 1, 2, 3 and 4 were tested according to the same method. The test results are shown in Table 1.

[0042] Table 1 Results of the wash-oil ratio test

[0043] As can be seen from Table 1: As can be seen from Comparative Example 1 and the present invention, the mixed solvent of 1-aminoethyl-2-heptadecylimidazoline and isopropanol / water has good oil-washing ability, while the present invention can significantly improve the oil-washing ability. As can be seen from Comparative Examples 2 and 3 and the present invention, the components of the present invention… ,

[0044] When used alone, it exhibits excellent oil-washing effects. As can be seen from this invention and Comparative Example 4, the oil-washing effect of this invention is far superior to that of commonly used commercially available oil-washing agents such as sodium dodecylbenzene sulfonate. As can be seen from this invention, Comparative Example 3, and Comparative Examples 1, 2, and 4, the corrosion-inhibiting effect of this invention is mainly due to the introduction of phosphate esters.

[0045] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any form or substance. It should be noted that those skilled in the art can make various improvements and additions without departing from the method of the present invention, and these improvements and additions are also considered to be within the scope of protection of the present invention. Any modifications, alterations, and equivalent changes made by those skilled in the art based on the above-disclosed technical content without departing from the spirit and scope of the present invention are equivalent embodiments of the present invention. Furthermore, any equivalent changes, alterations, and evolutions made to the above embodiments based on the essential technology of the present invention still fall within the scope of the technical solution of the present invention.

Claims

1. An environmentally friendly oil-removing liquid, characterized in that, The aforementioned environmentally friendly oil-removing liquid is composed of one or more of the following substances: 、 、 。 2. The method for preparing the clear oil solution as described in claim 1, characterized in that, The preparation method specifically includes the following steps: S1. Add 1-aminoethyl-2-heptadecylimidazoline and isopropanol / water mixed solvent (V:V=1:1) to the reactor, stir evenly, add sodium chloroethanesulfonate, keep the reaction at the temperature, and control the pH value to 7-8. S2. Add sodium 3-chloro-2-hydroxypropyl phosphate, keep the reaction at a constant temperature, and control the pH value to 7-8 to obtain an environmentally friendly clear oil solution. The molar ratio of sodium chloroethanesulfonate, sodium 3-chloro-2-hydroxypropyl phosphate, and 1-aminoethyl-2-heptadecylimidazoline is 0.1-1:0.1-1:

1.

3. The preparation method according to claim 2, characterized in that, The structural formula of the 1-aminoethyl-2-heptadecylimidazoline is as follows: ， The preparation method is referenced from Yan Jizhong, Shangguan Chengye, et al., Synthesis of 1-aminoethyl-2-heptadecylimidazoline, Guangdong Chemical Industry, 1997, 22-23.

4. The preparation method according to claim 2, characterized in that, The structural formula of the sodium 3-chloro-2-hydroxypropyl phosphate is as follows: ， The preparation method is described in "Surfactant Synthesis Technology", by Lü Tong, Chemical Industry Press, p.

202.

5. The preparation method according to claim 2, characterized in that, The heat preservation reaction described in S1 refers to a temperature of 50-60℃, a time of 1-2 hours, and a pH of 7-8.

6. The preparation method according to claim 2, characterized in that, The mass ratio of the isopropanol / water mixed solvent (V:V=1:1) described in S1 to 1-aminoethyl-2-heptadecylimidazoline is 10-12:

1.

7. The preparation method according to claim 2, characterized in that, The heat preservation reaction mentioned in S2 refers to a temperature of 60-70℃, a time of 2-4 hours, and a pH of 7-8.

8. The preparation method according to claim 2, characterized in that, The pH value of 7-8 is controlled using an aqueous solution of sodium hydroxide or potassium hydroxide.

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