Bactericidal corrosion inhibitor with oil displacement effect and preparation method thereof

Abstract

The present application relates to the technical field of corrosion inhibitor, in particular to a bactericidal corrosion inhibitor with oil displacement effect and a preparation method thereof.The bactericidal corrosion inhibitor is composed of 748-820 parts of double-hydrophobic chain-sulfobetaine end group imidazoline quaternary ammonium salt active substance, 1450-1550 parts of deionized water, 235-265 parts of isopropyl alcohol and 4-6 parts of sodium citrate dihydrate by mass fraction.The active substance is prepared by oil acid imidazoline, subsection end group sulfobetaine and long chain quaternary ammonium in sequence from oleic acid, N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine, 3-chloro-2-hydroxypropane sulfonic acid sodium and 1-bromododecane, 1-bromotetradecane or 1-bromohexadecane.The agent can play the roles of sterilization, corrosion inhibition, reduction of oil-water interfacial tension and oil film stripping when used in high salinity oilfield produced water or reinjection water system, and is suitable for oilfield produced water treatment and enhanced oil recovery operation.

Description

Technical Field

[0001] This invention relates to the field of corrosion inhibitor technology, and in particular to a bactericidal corrosion inhibitor with oil displacement function and its preparation method. Background Technology

[0002] As oilfield development enters its mid-to-late stages, the salinity of produced water gradually increases, leading to an increasingly urgent need for integrated agents that combine bactericidal, corrosion-inhibiting, and oil displacement functions. Existing oilfield bactericidal and corrosion-inhibiting systems often employ compound formulations of oleic acid-based hydroxyethyl imidazoline, dodecyl dimethyl benzyl ammonium chloride, phosphonic acid components, and polymeric organic guanidines, or compound formulations of alkoxyimidazoline quaternary ammonium compounds with other imidazoline derivatives. While these methods can achieve certain bactericidal and corrosion-inhibiting effects through component superposition, the problem of poor compatibility between compound components persists.

[0003] Meanwhile, existing oil displacement systems mostly employ betaine surfactants or betaine composite systems. While these can reduce oil-water interfacial tension and improve oil recovery, their interfacial characteristics differ significantly from those of the bactericidal and corrosion-inhibiting components, making stable coexistence within the same system difficult. In high-salinity reinjection or produced water environments, the shortcomings of these composite systems are further amplified: different components are prone to stratification and precipitation, leading to a significant decrease in dispersion stability; bactericidal and corrosion-inhibiting components compete for adsorption on carbon steel surfaces, failing to form a continuous and dense protective film, resulting in rapid degradation of corrosion inhibition efficiency over service life; and the interfacial activities of the oil displacement components and the bactericidal and corrosion-inhibiting components are mismatched, making it difficult to effectively reduce oil-water interfacial tension and resulting in significantly insufficient oil film stripping ability. These problems severely limit the application effectiveness of existing agents in high-salinity oilfield scenarios. Summary of the Invention

[0004] In view of this, the purpose of this invention is to propose a bactericide and corrosion inhibitor with oil displacement function and its preparation method, so as to solve the problem that existing compound bactericides and corrosion inhibitors in oilfields have poor compatibility and insufficient dispersion stability in produced water with high salinity, and are difficult to achieve multi-functional synergy of bactericide, corrosion inhibitor and oil displacement at the same time.

[0005] To achieve the above objectives, the present invention provides a bactericidal and corrosion inhibitor with oil displacement function. By mass, the bactericidal and corrosion inhibitor is prepared from the following raw materials: 748-820 parts of double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt active ingredient, 1450-1550 parts of deionized water, 235-265 parts of isopropanol and 4-6 parts of sodium citrate dihydrate. The active product of the double hydrophobic chain-sulfobetaine-terminated imidazoline quaternary ammonium salt is a reaction product having an oleic acid hydrocarbon chain, a sulfobetaine terminal group, and a long-chain alkyl quaternary ammonium group on the same oleic acid imidazoline skeleton, and is obtained by sequentially subjecting oleic acid, N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine, sodium 3-chloro-2-hydroxypropanesulfonate, and 1-bromolong-chain alkane to oleic acid imidazolineation, terminal sulfobetaineation, and long-chain quaternization. The 1-bromolong-chain alkane is one of 1-bromododecane, 1-bromotetradecane, or 1-bromohexadecane.

[0006] Furthermore, the active product of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt is obtained by reacting 485-536 parts of terminal sulfobetaine alkalized imidazoline intermediate, 249-305 parts of 1-bromolong-chain alkane and 680-720 parts of isopropanol and then removing the isopropanol.

[0007] Furthermore, the terminal sulfonated beet alkalized imidazoline intermediate is obtained by a segmented internal salting reaction of an oleic acid imidazoline intermediate containing a terminal tertiary amine and sodium 3-chloro-2-hydroxypropanesulfonate, wherein the segmented internal salting reaction includes a first-stage internal salting reaction and a second-stage supplementary internal salting reaction.

[0008] Further, the terminal sulfonated beet alkalized imidazoline intermediate is prepared by the following steps: mixing 355-395 parts of oleic acid imidazoline intermediate containing a terminal tertiary amine, 480-520 parts of anhydrous ethanol, and 190-210 parts of deionized water to obtain an oleic acid imidazoline intermediate solution containing a terminal tertiary amine; mixing 168-186 parts of sodium 3-chloro-2-hydroxypropanesulfonate, 10-12 parts of anhydrous sodium carbonate, and 280-320 parts of deionized water to obtain a first internal salting solution; and then... The solution was added to the oleic acid imidazoline intermediate containing the terminal tertiary amine for a first-stage internal salting reaction; 19-21 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 38-42 parts of deionized water were mixed to obtain a second internal salting solution; the second internal salting solution was added to the reaction solution after the first-stage internal salting reaction for a second-stage supplementary internal salting reaction; after the reaction was completed, ethanol was removed, and 760-840 parts of isopropanol were added to precipitate inorganic salts, which were then filtered and concentrated to obtain the terminal sulfobetaine alkalized imidazoline intermediate.

[0009] Furthermore, the first internal salting solution is added to the oleic acid imidazoline intermediate solution containing the terminal tertiary amine within 2 hours, and after the addition is completed, the temperature is raised to 82°C and the reaction is carried out for 5 hours; the second internal salting solution is added to the reaction solution after the first stage internal salting reaction within 1 hour, and the reaction is continued for 2 hours after the addition is completed.

[0010] Furthermore, the oleic acid imidazoline intermediate containing a terminal tertiary amine is obtained by reacting 260-300 parts of oleic acid, 130-145 parts of N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine and 280-320 parts of xylene.

[0011] Furthermore, the oleic acid imidazoline intermediate containing a terminal tertiary amine is prepared by the following steps: oleic acid, N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine and xylene are mixed and heated to 140-145°C under nitrogen protection, and reacted for 3 hours under xylene reflux and dehydration conditions; then xylene is distilled off until the temperature of the reaction solution rises to 168-172°C, and residual xylene is removed for another 30 minutes under 10 kPa conditions; then the temperature is raised to 190-194°C under nitrogen protection and held for 4 hours; after the holding period, the temperature is lowered to 90°C, and low-boiling substances are removed under reduced pressure under 10 kPa conditions to obtain the oleic acid imidazoline intermediate containing a terminal tertiary amine.

[0012] Furthermore, in the preparation of the dual hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt active product, the terminal sulfobetaine alkalized imidazoline intermediate, 1-bromolong-chain alkane and isopropanol are reacted at 80°C for 12 hours under nitrogen protection. After the reaction is completed, isopropanol is removed at 70°C and 10 kPa.

[0013] Furthermore, the 1-bromolong-chain alkane is 1-bromotetradecane.

[0014] Furthermore, the present invention also provides a method for preparing a bactericidal and corrosion inhibitor with oil displacement function, comprising the following steps: S1. Oleic acid, N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine and xylene are reacted to obtain an oleic acid imidazoline intermediate containing a terminal tertiary amine; S2. The oleic acid imidazoline intermediate containing tertiary amine is subjected to a segmented internal salting reaction with sodium 3-chloro-2-hydroxypropanesulfonate to obtain the terminal sulfobetaine alkalized imidazoline intermediate. S3. The terminal sulfobetaine imidazoline intermediate is subjected to a long-chain quaternization reaction with 1-bromolong-chain alkane to obtain the active product of bihydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt. S4. The active ingredient of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt, deionized water, isopropanol and sodium citrate dihydrate are mixed and filtered to obtain a bactericidal and corrosion inhibitor with oil displacement effect.

[0015] The beneficial effects of this invention are: (1) By integrating sulfobetaine end groups, long-chain quaternized hydrophobic chains and oleic acid adsorption sites in the same oleic acid imidazoline skeleton, this invention avoids the component compatibility problem of traditional compound systems. The amount of precipitation in simulated produced water with high mineralization is as low as 0.4-1.6 mg / 100 mL after standing for 7 days, and the dispersion stability is significantly improved.

[0016] (2) The long-chain quaternized structure endows it with high-efficiency bactericidal properties, with a kill rate of 99.5%-99.9% against sulfate-reducing bacteria; the oleic acid adsorption sites and sulfobetaine work synergistically to form a continuous hydrophobic adsorption film on the carbon steel surface, reducing the carbon steel corrosion rate to 0.024-0.039 mm / a and the corrosion inhibition rate to 90.8%-94.4%.

[0017] (3) The synergistic effect of the interface between the double hydrophobic chain and sulfobetaine reduces the interfacial tension of oil and water to 0.009-0.021 mN / m, the static oil film stripping rate reaches 83.2%-91.6%, and the physical simulation oil displacement improves the recovery rate by 9.2%-11.8%, realizing the multi-functional synergistic effect of sterilization, corrosion inhibition and oil displacement. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0019] Example 1: Step 1: Weigh 282g of oleic acid, 138g of N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine, and 300g of xylene and add them to a conventional reaction vessel equipped with a mechanical stirrer, thermometer, reflux condenser, and water separator. After purging with nitrogen three times, maintain a slight positive pressure of nitrogen and stir at 300r / min to raise the temperature to 142℃. React for 3h under xylene reflux and water separation conditions. Then switch to atmospheric distillation to remove xylene until the reaction solution temperature rises to 170℃. Continue to remove residual xylene under 10kPa conditions for 30min. Then restore nitrogen protection and raise the temperature of the reaction solution to 192℃ and hold for 4h. Cool the reaction solution to 90℃ and remove low-boiling substances under reduced pressure at 10kPa conditions to obtain an oleic acid imidazoline intermediate containing a terminal tertiary amine.

[0020] Step 2: Weigh 374g of the oleic acid imidazoline intermediate containing the terminal tertiary amine obtained in Step 1, 500g of anhydrous ethanol and 200g of deionized water and add them to the reaction vessel. Stir at 60℃ and 300r / min for 30min. Separately weigh 177g of sodium 3-chloro-2-hydroxypropanesulfonate, 11g of anhydrous sodium carbonate and 300g of deionized water and stir at 40℃ until the solid is completely dissolved to obtain the first internal salting solution. Add the first internal salting solution dropwise to the oleic acid imidazoline intermediate solution containing the terminal tertiary amine over 2h. After the addition is complete, raise the temperature to 82℃ and react for 5h. Subsequently, 20g of sodium 3-chloro-2-hydroxypropanesulfonate and 40g of deionized water were weighed to prepare a second internal salting solution. The temperature of the reaction solution was lowered to 60℃, and the second internal salting solution was added dropwise over 1 hour. After the addition was completed, the reaction continued for 2 hours. After the reaction was completed, ethanol was removed under conditions of 70℃ and 10kPa. 800g of isopropanol was added to the concentrated solution and stirred at 300r / min for 1 hour at 25℃ to precipitate inorganic salts. The precipitated inorganic salts were removed by filtration, and the filtrate was concentrated under conditions of 70℃ and 10kPa to obtain the terminal sulfobetaine alkalized imidazoline intermediate.

[0021] Step 3: Weigh 510g of the terminal sulfobetaine imidazoline intermediate obtained in Step 2, 305g of 1-bromohexadecane and 700g of isopropanol and add them to the reaction vessel. After purging with nitrogen three times, stir at 300r / min and heat to 80℃, and keep the reaction at this temperature for 12h. After the reaction is completed, lower the reaction solution to 70℃ and remove the isopropanol under 10kPa conditions to obtain the active product of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt.

[0022] Step 4: Weigh 815g of the active ingredient of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt obtained in Step 3, 1500g of deionized water, 250g of isopropanol and 5g of sodium citrate dihydrate and add them to the mixing container. Stir for 1h at 45℃ and 300r / min, and then filter with a filter membrane with a pore size of 5μm to obtain a bactericidal and corrosion inhibitor with oil displacement effect.

[0023] Example 2: Step 1: Weigh 268g of oleic acid, 131g of N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine, and 285g of xylene into a conventional reaction vessel equipped with a mechanical stirrer, thermometer, reflux condenser, and water separator. After purging with nitrogen three times, maintain a slight positive pressure of nitrogen and stir at 300r / min to raise the temperature to 140℃. React for 3h under xylene reflux and water separation conditions. Then switch to atmospheric distillation to remove xylene until the reaction solution temperature rises to 168℃. Continue to remove residual xylene under 10kPa conditions for 30min. Then restore nitrogen protection, raise the temperature of the reaction solution to 190℃, and keep it at this temperature for 4h. Cool the reaction solution to 90℃ and remove low-boiling substances under reduced pressure at 10kPa conditions to obtain an oleic acid imidazoline intermediate containing a terminal tertiary amine.

[0024] Step 2: Weigh 355g of the oleic acid imidazoline intermediate containing the terminal tertiary amine obtained in Step 1, 480g of anhydrous ethanol and 190g of deionized water and add them to the reaction vessel. Stir at 60℃ and 300r / min for 30min. Separately weigh 168g of sodium 3-chloro-2-hydroxypropanesulfonate, 10g of anhydrous sodium carbonate and 285g of deionized water and stir at 40℃ until the solid is completely dissolved to obtain the first internal salting solution. Add the first internal salting solution dropwise to the oleic acid imidazoline intermediate solution containing the terminal tertiary amine within 2h. After the addition is complete, raise the temperature to 82℃ and react for 5h. Subsequently, 19g of sodium 3-chloro-2-hydroxypropanesulfonate and 38g of deionized water were weighed to prepare a second internal salting solution. The temperature of the reaction solution was lowered to 60℃, and the second internal salting solution was added dropwise over 1 hour. After the addition was completed, the reaction continued for 2 hours. After the reaction was completed, ethanol was removed under conditions of 70℃ and 10kPa. 760g of isopropanol was added to the concentrate and stirred at 300r / min for 1 hour at 25℃ to precipitate inorganic salts. The precipitated inorganic salts were removed by filtration, and the filtrate was concentrated under conditions of 70℃ and 10kPa to obtain the terminal sulfobetaine alkalized imidazoline intermediate.

[0025] Step 3: Weigh 485g of the terminal sulfobetaine imidazoline intermediate obtained in Step 2, 263g of 1-bromotetradecane and 690g of isopropanol and add them to the reaction vessel. After purging with nitrogen three times, stir at 300r / min and heat to 80℃, and keep the reaction at this temperature for 12h. After the reaction is completed, lower the reaction solution to 70℃ and remove the isopropanol under 10kPa conditions to obtain the active product of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt.

[0026] Step 4: Weigh 748g of the active ingredient of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt obtained in Step 3, 1450g of deionized water, 235g of isopropanol and 4g of sodium citrate dihydrate and add them to the mixing container. Stir for 1 hour at 45℃ and 300r / min, and then filter with a filter membrane with a pore size of 5μm to obtain a bactericidal and corrosion inhibitor with oil displacement effect.

[0027] Example 3: Step 1: Weigh 296g of oleic acid, 145g of N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine, and 315g of xylene into a conventional reaction vessel equipped with a mechanical stirrer, thermometer, reflux condenser, and water separator. After purging with nitrogen three times, maintain a slight positive pressure of nitrogen and stir at 300r / min to raise the temperature to 145℃. React for 3h under xylene reflux and water separation conditions. Then switch to atmospheric distillation to remove xylene until the reaction solution temperature rises to 172℃. Continue to remove residual xylene under 10kPa conditions for 30min. Then restore nitrogen protection, raise the temperature of the reaction solution to 194℃, and keep it at this temperature for 4h. Cool the reaction solution to 90℃ and remove low-boiling substances under reduced pressure at 10kPa conditions to obtain an oleic acid imidazoline intermediate containing a terminal tertiary amine.

[0028] Step 2: Weigh 393g of the oleic acid imidazoline intermediate containing the terminal tertiary amine obtained in Step 1, 520g of anhydrous ethanol and 210g of deionized water and add them to the reaction vessel. Stir at 60℃ and 300r / min for 30min. Separately weigh 186g of sodium 3-chloro-2-hydroxypropanesulfonate, 12g of anhydrous sodium carbonate and 315g of deionized water and stir at 40℃ until the solid is completely dissolved to obtain the first internal salting solution. Add the first internal salting solution dropwise to the oleic acid imidazoline intermediate solution containing the terminal tertiary amine over 2h. After the addition is complete, raise the temperature to 82℃ and react for 5h. Subsequently, 21g of sodium 3-chloro-2-hydroxypropanesulfonate and 42g of deionized water were weighed to prepare a second internal salting solution. The temperature of the reaction solution was lowered to 60℃, and the second internal salting solution was added dropwise over 1 hour. After the addition was completed, the reaction was continued for 2 hours. After the reaction was completed, ethanol was removed under conditions of 70℃ and 10kPa. 840g of isopropanol was added to the concentrate and stirred at 300r / min for 1 hour at 25℃ to precipitate inorganic salts. The precipitated inorganic salts were removed by filtration, and the filtrate was concentrated under conditions of 70℃ and 10kPa to obtain the terminal sulfobetaine alkalized imidazoline intermediate.

[0029] Step 3: Weigh 536g of the terminal sulfobetaine imidazoline intermediate obtained in Step 2, 262g of 1-bromododecane and 720g of isopropanol and add them to the reaction vessel. After purging with nitrogen three times, stir at 300r / min and heat to 80℃, and keep the temperature for 12h. After the reaction is completed, cool the reaction solution to 70℃ and remove isopropanol under 10kPa to obtain the active product of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt.

[0030] Step 4: Weigh 798g of the active ingredient of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt obtained in Step 3, 1550g of deionized water, 265g of isopropanol and 6g of sodium citrate dihydrate and add them to the mixing container. Stir for 1h at 45℃ and 300r / min, and then filter with a filter membrane with a pore size of 5μm to obtain a bactericidal and corrosion inhibitor with oil displacement effect.

[0031] Comparative Example 1: The difference from Example 1 is as follows: in step two, 177g of sodium 3-chloro-2-hydroxypropanesulfonate and 20g of sodium 3-chloro-2-hydroxypropanesulfonate are not added, and 197g of deionized water is used to make up the corresponding feed mass, and 11g of anhydrous sodium carbonate is not added; in step three, 305g of 1-bromohexadecane is added for long-chain quaternization as in Example 1; in step four, the mass fraction of organic active matter in the final sample is calculated according to the mass of the obtained active matter to be consistent with that in Example 1, and the other conditions are the same as in Example 1.

[0032] Comparative Example 2: The difference from Example 1 is that the reaction order of steps two and three in Example 1 is reversed. Specifically, the oleic acid imidazoline intermediate containing the terminal tertiary amine obtained in step one is reacted with 305g of 1-bromohexadecane in 700g of isopropanol at 80°C for 12h. Then, the same amount of sodium 3-chloro-2-hydroxypropanesulfonate, anhydrous sodium carbonate, anhydrous ethanol, and deionized water as in Example 1 are added to carry out an internal salting reaction. In step four, the mass fraction of organic active matter in the final sample is calculated according to the mass of the obtained active matter to ensure that it is consistent with that in Example 1. All other conditions are the same as in Example 1.

[0033] Comparative Example 3: The difference from Example 1 is that in step two, only the first internal salting solution prepared by 177g of sodium 3-chloro-2-hydroxypropanesulfonate, 11g of anhydrous sodium carbonate and 300g of deionized water is added, and the second internal salting solution prepared by 20g of sodium 3-chloro-2-hydroxypropanesulfonate and 40g of deionized water is no longer added, and 60g of deionized water is used to make up the corresponding liquid addition amount; in step four, the mass fraction of organic active matter in the final sample is calculated according to the obtained active matter mass to be consistent with that in Example 1, and the other conditions are the same as in Example 1.

[0034] Comparative Example 4: The difference from Example 1 is that: in step three, 305g of 1-bromohexadecane is not added, but only 510g of the terminal sulfobetaine alkalized imidazoline intermediate obtained in step two and 700g of isopropanol are kept at 80°C for 12h, and then the isopropanol is removed; in step four, the mass fraction of organic active matter in the final sample is calculated according to the mass of the obtained active matter to be consistent with that in Example 1, and the other conditions are the same as in Example 1.

[0035] Comparative Example 5: The difference from Example 1 is that in step two, 177g of sodium 3-chloro-2-hydroxypropanesulfonate, 20g of sodium 3-chloro-2-hydroxypropanesulfonate, 11g of anhydrous sodium carbonate, 340g of deionized water, 500g of anhydrous ethanol and 374g of the oleic acid imidazoline intermediate containing the terminal tertiary amine obtained in step one are added to the reaction vessel at once, and the reaction is carried out at 82°C for 7 hours. The step two does not use the segmented method of adding the first internal salting solution dropwise and the second internal salting solution afterward. Steps three and four are the same as in Example 1.

[0036] Performance testing: Note: The bactericidal and corrosion inhibitors with oil displacement effects obtained from Examples 1-3 and Comparative Examples 1-5 were used as test samples. All samples were tested in the final aqueous form. Before testing, the samples were allowed to stand at 25°C for 24 hours. If visible bubbles were present, they were eliminated by stirring at 25°C and 200 rpm for 10 minutes, followed by standing for 30 minutes. Unless otherwise specified, the test water was deionized water meeting the requirements of Grade III water in GB / T 6682-2008. The high-mineralization simulated produced water was prepared from 70,000 mg / L sodium chloride, 5,000 mg / L calcium chloride, 2,000 mg / L magnesium chloride, 1,000 mg / L sodium bicarbonate, and 1,000 mg / L sodium sulfate, and its pH was adjusted to 7.2 using hydrochloric acid or sodium hydroxide solution. The test crude oil was dehydrated crude oil with a viscosity of 12 mPa·s at 45°C, and was kept at a constant temperature of 45°C for 2 hours before testing. The carbon steel test piece was made of Q235 carbon steel, with dimensions of 50mm×25mm×2mm. It was polished with 400-grit, 800-grit, and 1200-grit sandpaper in sequence, then cleaned with anhydrous ethanol and acetone, dried, and weighed for later use.

[0037] Aqueous solution pH and high mineralization dispersion stability tests: pH was tested according to GB / T 6368-2008 "Determination of pH of Aqueous Solutions of Surfactants - Potentiometric Method". The sample was prepared into a 1% (w / w) aqueous solution with deionized water, and the pH was measured after being kept at 25℃ for 30 min. For the high mineralization dispersion stability test, the sample was added to simulated high mineralization produced water to prepare a 2000 mg / L sample solution, which was placed in a 100 mL stoppered graduated cylinder and allowed to stand at 45℃ for 7 days. Observation was conducted to check for layering, turbidity, or precipitation. The precipitate was filtered through a 0.45 μm filter membrane, dried at 60℃ to constant weight, and weighed. The result was expressed as the amount of precipitation per 100 mL of sample solution.

[0038] Sulfate-reducing bacteria kill rate test: Indoor bactericidal performance evaluation was conducted according to SY / T 5757-2024 "Technical Specification for Bactericides for Water Injection Treatment". A suspension of sulfate-reducing bacteria, separated and enriched from oilfield produced water, was added to high-salinity simulated produced water to achieve an initial bacterial count of 1.0 × 10⁻⁶. 5The concentration of sulfate-reducing bacteria in the bacterial culture was increased to 100 mg / L. No sample was added to the blank culture. Each sample was placed in an anaerobic culture flask and incubated at 45°C for 24 hours. The number of sulfate-reducing bacteria after incubation was counted using the trace dilution method. The sulfate-reducing bacteria kill rate was calculated by dividing the difference between the initial bacterial count and the post-incubation bacterial count by the initial bacterial count and then multiplying by 100%.

[0039] Corrosion rate and corrosion inhibition rate testing of carbon steel: The static weight loss method was used for evaluation according to SY / T 5273-2014 "Performance Inhibitors and Evaluation Methods for Oilfield Produced Water Treatment". Pretreated and weighed Q235 carbon steel samples were immersed in simulated produced water with high salinity containing 100 mg / L of the test sample, with a liquid-to-solid ratio of 40 mL / cm³. 2 The test temperature was 60℃, and the test time was 72 hours; no test sample was added to the blank sample. After the test, the test piece was removed and washed sequentially with deionized water and anhydrous ethanol. Corrosion products were removed by acid washing, and the sample was dried and weighed. The corrosion rate was calculated based on the mass loss of the test piece, the exposed area of ​​the test piece, and the test time. The corrosion inhibition rate was calculated by dividing the difference between the corrosion rate of the blank sample and the corrosion rate of the added sample by the corrosion rate of the blank sample.

[0040] Oil-water interfacial tension testing: The test was conducted according to the rotating drop method in SY / T 5370-2018 "Methods for Determination of Surface and Interfacial Tension". The sample to be tested was added to simulated produced water with high salinity to prepare a sample solution of 2000 mg / L. Using dehydrated crude oil at a constant temperature of 45℃ as the oil phase and the sample solution as the water phase, a rotating drop interfacial tensiometer was used to test for 30 min at 45℃ and 6000 r / min. Before the test, the densities of the oil and water phases at 45℃ were measured separately, and the density difference was input into the instrument's calculation program. Each sample was tested in triplicate, and the average value was taken. The relative deviation of the parallel tests should not exceed 10%.

[0041] Static oil film stripping rate test: The test was conducted according to the evaluation methods for emulsification, solubilization, and oil film stripping of the oil displacement system in SY / T 6424-2014 "Performance Test Methods for Composite Oil Displacement Systems". A clean glass slide was immersed in dehydrated crude oil at 45℃ for 30 minutes, then removed and suspended vertically for 10 minutes. The mass of the oil film was measured. Subsequently, the oil-coated glass slide was immersed in 2000 mg / L of high-mineralization simulated produced water of the test sample, left to stand at 45℃ for 2 hours, removed, suspended vertically for 10 minutes, and the mass of the remaining oil film was measured. The static oil film stripping rate was calculated by dividing the difference between the oil film mass and the remaining oil film mass by the oil film mass and then multiplying by 100%. The blank sample was tested using high-mineralization simulated produced water without the test sample.

[0042] Physical simulation oil displacement effect test: The physical simulation oil displacement experiment using sand-filled tubes was conducted according to SY / T 6424-2014 "Performance Test Method for Composite Oil Displacement Systems". Sand-filled tubes with a diameter of 25 mm and a length of 300 mm were used. After sand filling, the gas permeability was controlled at 50 mD, and the porosity was controlled at 18%. The sand-filled tubes were then evacuated and saturated with high-salinity simulated produced water, followed by displacement with dehydrated crude oil at 45℃ until the outlet water cut was below 2%. After aging for 12 hours, water flooding was performed with high-salinity simulated produced water until the outlet water cut reached 98%. Subsequently, 0.3 times the pore volume of the 2000 mg / L sample solution was injected, followed by another 0.7 times the pore volume of high-salinity simulated produced water. The percentage of newly produced oil after chemical slugging relative to the original oil cut was used as the enhanced oil recovery value. The blank sample was subjected to the same conditions with only the continued injection of high-salinity simulated produced water.

[0043] Table 1 Performance test results of the examples and comparative examples

[0044] As shown in Table 1, the blank sample, without the addition of organic active substances, did not exhibit bactericidal, corrosion-inhibiting, or oil-displacement effects in simulated produced water with high salinity. The sulfate-reducing bacteria kill rate was 0%, and the corrosion rate of Q235 carbon steel reached 0.426 mm·a. -1 The interfacial tension between oil and water is 27.600 mN·m. -1 Compared with Comparative Examples 1 and 4, under the same organic active ingredient mass fraction, Example 1 showed an increase in the sulfate-reducing bacteria kill rate from 96.8% and 87.6% to 99.8%, and an increase in the carbon steel corrosion rate from 0.093 mm·a. -1 and 0.129 mm·a -1 Reduced to 0.024 mm·a -1 The interfacial tension between oil and water decreased from 0.310 mN·m -1 and 0.096mN·m -1 Reduced to 0.014 mN·m -1 The recovery rate increased from 3.4% and 6.7% to 10.4%, indicating that neither long-chain quaternization nor the introduction of sulfobetaine end groups can simultaneously achieve bactericidal, corrosion-inhibiting, and oil displacement effects. The structural construction method of sulfobetaine alkalization at the front end followed by long-chain quaternization at the nitrogen position of imidazoline is more conducive to the synergistic effect of multiple functions.

[0045] As can be seen from Comparative Examples 3 and 5, when sodium 3-chloro-2-hydroxypropanesulfonate was reduced in the second stage and then supplemented or when a single-stage internal salting process was used, the precipitation amount of the samples increased to 6.1 mg / 100 mL over 7 days. -1 and 4.9 mg·100 mL -1 The interfacial tensions of oil and water are 0.039 mN·m. -1and 0.057mN·m -1 The overall performance of all samples was lower than that of Example 1, indicating that segmented intra-salinization is beneficial to improving the degree of intra-terminal salinization and the dispersion stability in high-mineralization systems.

[0046] Examples 1-3 all exhibited low corrosion rates, high sulfate-reducing bacteria kill rates, and good oil film stripping and physical displacement effects. Example 1, using 1-bromohexadecane, showed the lowest corrosion rate on carbon steel at 0.024 mm·a. -1 The corrosion inhibition rate reached 94.4%, indicating that longer hydrophobic segments are more conducive to forming a hydrophobic adsorption layer on the carbon steel surface; Example 2 used 1-bromotetradecane, which had the lowest oil-water interfacial tension of 0.009 mN·m. -1 The static oil film stripping rate and enhanced oil recovery rate reached 91.6% and 11.8%, respectively, indicating that the C14 segment exhibited a good overall balance between aqueous phase dispersibility, oil-water interface orientation, and hydrophobic effects. Example 3 used 1-bromododecane, which showed the lowest precipitation amount after 7 days, at 0.4 mg / 100 mL. -1 This indicates that shorter long-chain alkyl groups are beneficial for improving dispersion stability in highly salinized aqueous phases.

[0047] In summary, this invention introduces sulfobetaine end groups, imidazoline adsorption sites, and long-chain quaternized hydrophobic segments into the same imidazoline molecular skeleton, enabling bactericidal, corrosion-inhibiting, and oil displacement effects to be synergistically manifested in the same aqueous system. In particular, Example 2 shows superior performance in terms of bactericidal rate, interfacial tension, oil film stripping rate, and enhanced oil recovery, demonstrating good potential for bactericidal, corrosion-inhibiting, and oil displacement applications in oilfield produced water.

[0048] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A bactericidal and corrosion inhibitor with oil displacement properties, characterized in that, The bactericidal and corrosion inhibitor is prepared from the following raw materials by mass: 748-820 parts of double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt active ingredient, 1450-1550 parts of deionized water, 235-265 parts of isopropanol and 4-6 parts of sodium citrate dihydrate. The active product of the double hydrophobic chain-sulfobetaine-terminated imidazoline quaternary ammonium salt is a reaction product having an oleic acid hydrocarbon chain, a sulfobetaine terminal group, and a long-chain alkyl quaternary ammonium group on the same oleic acid imidazoline skeleton, and is obtained by sequentially subjecting oleic acid, N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine, sodium 3-chloro-2-hydroxypropanesulfonate, and 1-bromolong-chain alkane to oleic acid imidazolineation, terminal sulfobetaineation, and long-chain quaternization. The 1-bromolong-chain alkane is one of 1-bromododecane, 1-bromotetradecane, or 1-bromohexadecane; The active ingredient of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt is obtained by reacting 485-536 parts of terminal sulfobetaine alkalized imidazoline intermediate, 249-305 parts of 1-bromolong-chain alkane and 680-720 parts of isopropanol and then removing isopropanol. The terminal sulfonated beet alkalized imidazoline intermediate is prepared by the following steps: 355-395 parts of an oleic acid imidazoline intermediate containing a terminal tertiary amine, 480-520 parts of anhydrous ethanol, and 190-210 parts of deionized water are mixed to obtain an oleic acid imidazoline intermediate solution containing a terminal tertiary amine; 168-186 parts of sodium 3-chloro-2-hydroxypropanesulfonate, 10-12 parts of anhydrous sodium carbonate, and 280-320 parts of deionized water are mixed to obtain a first internal salting solution; the first internal salting solution is added to… The oleic acid imidazoline intermediate solution containing a terminal tertiary amine is subjected to a first-stage internal salting reaction; 19-21 parts of sodium 3-chloro-2-hydroxypropanesulfonate and 38-42 parts of deionized water are mixed to obtain a second internal salting solution; the second internal salting solution is added to the reaction solution after the first-stage internal salting reaction to carry out a second-stage supplementary internal salting reaction; after the reaction is completed, ethanol is removed, 760-840 parts of isopropanol are added to precipitate inorganic salts, and the solution is filtered and concentrated to obtain the terminal sulfobetaine alkalized imidazoline intermediate; The preparation steps of the bactericidal and corrosion inhibitor with oil displacement function include: S1. Oleic acid, N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine and xylene are reacted to obtain an oleic acid imidazoline intermediate containing a terminal tertiary amine; S2. The oleic acid imidazoline intermediate containing a terminal tertiary amine is subjected to a segmented internal salting reaction with sodium 3-chloro-2-hydroxypropanesulfonate to obtain a terminal sulfobetaine alkalized imidazoline intermediate. S3. The terminal sulfobetaine imidazoline intermediate is subjected to a long-chain quaternization reaction with 1-bromolong-chain alkane to obtain the active product of bihydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt. S4. The active ingredient of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt, deionized water, isopropanol and sodium citrate dihydrate are mixed and filtered to obtain a bactericidal and corrosion inhibitor with oil displacement effect.

2. The bactericidal and corrosion inhibitor with oil displacement effect according to claim 1, characterized in that, The first internal salting solution is added to the oleic acid imidazoline intermediate solution containing the terminal tertiary amine within 2 hours, and after the addition is completed, the temperature is raised to 82°C and the reaction is carried out for 5 hours; the second internal salting solution is added to the reaction solution after the first stage internal salting reaction within 1 hour, and the reaction is continued for 2 hours after the addition is completed.

3. The bactericidal and corrosion inhibitor with oil displacement effect according to claim 1, characterized in that, The oleic acid imidazoline intermediate containing a terminal tertiary amine is obtained by reacting 260-300 parts of oleic acid, 130-145 parts of N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine and 280-320 parts of xylene.

4. The bactericidal and corrosion inhibitor with oil displacement effect according to claim 3, characterized in that, The oleic acid imidazoline intermediate containing a terminal tertiary amine was prepared by the following steps: oleic acid, N2-(2-aminoethyl)-N1,N1-dimethylethylenediamine and xylene were mixed and heated to 140-145°C under nitrogen protection, and reacted for 3 hours under xylene reflux and dehydration conditions; then the xylene was distilled off until the temperature of the reaction solution rose to 168-172°C, and the residual xylene was further removed under 10 kPa conditions for 30 minutes; then the temperature was raised to 190-194°C under nitrogen protection and held for 4 hours. After the heat preservation was completed, the temperature was lowered to 90℃, and the low-boiling substances were removed under reduced pressure at 10 kPa to obtain an oleic acid imidazoline intermediate containing a terminal tertiary amine.

5. The bactericidal and corrosion inhibitor with oil displacement effect according to claim 1, characterized in that, In the preparation of the active product of the double hydrophobic chain-sulfobetaine terminal imidazoline quaternary ammonium salt, the terminal sulfobetaine alkalized imidazoline intermediate, 1-bromolong-chain alkane and isopropanol are reacted at 80°C for 12 h under nitrogen protection. After the reaction is completed, isopropanol is removed at 70°C and 10 kPa.

6. The bactericidal and corrosion inhibitor with oil displacement effect according to claim 1, characterized in that, The 1-bromolong-chain alkane is 1-bromotetradecane.

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