A demulsifier composition for complex heavy oil produced fluid and preparation method thereof

Abstract

The present invention relates to a demulsifier composition for complex heavy oil produced fluid and a preparation method thereof. A demulsifier composition for complex heavy oil produced fluid is composed of the following components, calculated by mass percentage: 5% to 10% of a cage-type capture agent, 30% to 40% of a demulsifier, 10% to 15% of a cationic surfactant, 5% to 15% of a small molecule auxiliary agent, and the balance is water. A preparation method for a demulsifier composition for complex heavy oil produced fluid comprises the following steps: (1) preparing a cage-type capture agent; (2) respectively weighing a formulated amount of a cage-type capture agent, a demulsifier, a cationic surfactant, a small molecule auxiliary agent and water into a reaction container, mixing and uniformly stirring, and then heating and stirring to obtain a demulsifier composition for complex heavy oil produced fluid. The present invention has the following beneficial effects: 1. It can reduce the viscosity of the oil phase, making the interfacial film easier to break; 2. Finally, the polyethylene polyamine-based demulsifier is adsorbed on the interfacial film, completely destroying the interfacial film.

Description

Technical Field

[0001] The invention belongs to the technical field of crude oil treatment and processing, and particularly relates to a demulsifier composition for complex heavy oil produced fluid and a preparation method thereof. Background Art

[0002] Polymer-petroleum sulfonate binary flooding is the primary flooding system used to enhance oil recovery in medium-to-high permeability heavy oil reservoirs. However, while the polymers and petroleum sulfonates used in binary flooding improve oil recovery, they also increase the difficulty of demulsification and dehydration of the produced emulsions from the binary flooding in heavy oil reservoirs. The polymer primarily increases the viscosity of the produced fluid from the binary flooding, creating an intermediate layer at the oil-water interface and improving the stability of the produced emulsions from the binary flooding in heavy oil reservoirs. Furthermore, the lower the polymer molecular weight and the higher the polymer concentration, the more stable the produced emulsion from the binary flooding, but the more difficult it is to demulsify and dehydrate the emulsion. The significant synergistic effect between the petroleum sulfonate and the polymer hinders emulsion demulsification and dehydration.

[0003] For produced fluids from ASP flooding in heavy oil reservoirs, the current approach to dehydrating the crude oil is to add chemical agents such as demulsifiers, flocculants, or reverse demulsifiers, combined with physical demulsification methods such as multi-stage sedimentation, heating, and electrical dehydration. If the produced fluids from ASP flooding are stable, conventional demulsifiers combined with current treatment processes can fully reduce the water content of the crude oil to within acceptable limits. However, to increase crude oil production, a series of production-enhancing measures are often employed, including acidification, fracturing, and the addition of heavy oil viscosity reducers. Although the implementation of production-increasing measures has effectively increased crude oil production, it has also directly led to a substantial increase in the concentration of oilfield additives (mainly including high-valent metal ions and low-valent alkylbenzene sulfonates) in the produced fluid of binary flooding and composite flooding in heavy oil reservoirs. Low-valent alkylbenzene sulfonates and high-valent metal cations undergo a replacement reaction to generate oil-soluble high-valent alkylbenzene sulfonates, making the oil-in-water emulsion more stable and carrying out more formation rock dissolutions, resulting in changes in the properties of the produced emulsion of binary flooding and composite flooding in heavy oil reservoirs, further increasing the difficulty of demulsification and dehydration of the produced fluid of binary flooding and composite flooding, resulting in high water content in crude oil, which seriously affects the production operation of the oil field. Summary of the Invention

[0004] To address the above-mentioned technical problems, the present invention provides a demulsifier composition for complex heavy oil production fluids and a preparation method thereof. This demulsifier composition has a simple preparation method, high synthesis efficiency (the caged capture agent is synthesized using grafting and substitution reactions, with a raw material conversion rate exceeding 90%), safety and environmental protection (one of the raw materials for the caged capture agent is cyclodextrin, a cyclic oligosaccharide produced from amylose under the action of enzymes, which is easily biodegradable and environmentally friendly), easy dosage and use, and high demulsification and dehydration efficiency.

[0005] Technical solution: A demulsifier composition for complex heavy oil produced fluid, which is composed of the following components in percentage by mass:

[0006] 5% to 10% cage capture agent, 30% to 40% demulsifier, 10% to 15% cationic surfactant, 5% to 15% small molecule additive, and the balance is water.

[0007] Furthermore, the caged capture agent is at least one of the following four types of compounds:

[0008]

[0009] Wherein R, R1, and R2 are normal or isomeric alkyl groups with 8 to 14 carbon atoms, and X is one of Cl, Br, and I.

[0010] Furthermore, the demulsifier is ethylenediamine polyoxyethylene polyoxypropylene ether, diethylenetriamine polyoxyethylene polyoxypropylene ether, triethylenetetramine polyoxyethylene polyoxypropylene ether, tetraethylenepentamine polyoxyethylene polyoxypropylene ether, pentaethylenehexamine polyoxyethylene polyoxypropylene ether, hexaethyleneheptamine polyoxyethylene polyoxypropylene ether, ethylenediamine polyoxyethylene polyoxypropylene polyoxyethylene ether, diethylenetriamine polyoxyethylene polyoxypropylene polyoxyethylene ether, triethylenetetramine polyoxyethylene polyoxypropylene polyoxyethylene ether, tetraethylenepentamine polyoxyethylene polyoxypropylene One or more of propylene glycol polyoxyethylene ether, pentaethylene hexamine polyoxyethylene polyoxypropylene polyoxyethylene ether, hexaethylene heptamine polyoxyethylene polyoxypropylene polyoxyethylene ether, ethylenediamine polyoxypropylene polyoxyethylene polyoxypropylene ether, diethylenetriamine polyoxypropylene polyoxyethylene polyoxypropylene ether, triethylenetetramine polyoxypropylene polyoxyethylene polyoxypropylene ether, tetraethylenepentamine polyoxypropylene polyoxyethylene polyoxypropylene ether, pentaethylene hexamine polyoxypropylene polyoxyethylene polyoxypropylene ether, and hexaethylene heptamine polyoxypropylene polyoxyethylene polyoxypropylene ether.

[0011] Furthermore, the cationic surfactant is one or more of an alkyl monoquaternary ammonium salt surfactant, a gemini quaternary ammonium salt surfactant, and a triquaternary ammonium salt surfactant.

[0012] Furthermore, the alkyl monoquaternary ammonium salt surfactant is one or more of dodecyltrimethylammonium chloride, tridecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, pentadecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tridecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, pentadecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

[0013] Furthermore, the general formula of the gemini quaternary ammonium salt surfactant is:

[0014]

[0015] Wherein: y=2-4, n=8-16, m=8-16, and X is one of Cl, Br, and I.

[0016] Furthermore, the triquaternary ammonium salt surfactant is an alkyl fatty amine polyoxyethylene ether triquaternary ammonium salt, and its general formula is as follows:

[0017]

[0018] Wherein: n=8-16, p=4-7, q=4-7, and X is one of Cl, Br, and I.

[0019] Furthermore, the small molecule auxiliary agent is one or more of n-octane, nonylphenol polyoxyethylene ether, n-heptane, ethanol, isopropanol, and petroleum ether.

[0020] A method for preparing a demulsifier composition for complex heavy oil produced fluid, which comprises the following steps, calculated by weight:

[0021] (1) Preparation of caged capture agent:

[0022] (11) Add 115-125 parts of amino-β-cyclodextrin or diethylenetriamine-β-cyclodextrin to a reaction vessel, add 100 parts of distilled water, stir and heat, reflux with cold water, control the heating temperature at 30-60°C, and then stop the nitrogen flow after passing nitrogen for 20-40 minutes;

[0023] (12) adding 0.5 to 1 parts of urea peroxide and 1 to 3 parts of ascorbic acid to the reaction vessel, and then dropwise adding 9 to 28 parts of ethylene glycol to the reaction vessel. After the dropwise addition is completed, the reaction is continued for 3 to 5 hours to obtain an intermediate reaction system;

[0024] (13) adding an alkaline aqueous solution to the intermediate reaction system obtained in step (12), adjusting the pH value of the intermediate reaction system to neutral, and then vacuum distilling to remove water to obtain an intermediate product;

[0025] (14) The intermediate product obtained in step (13) is dissolved in 100 parts of isopropanol, and then 0.5 to 5 parts of potassium iodide are added, stirred and heated to 70 to 90°C, refluxed with cold water, and then 18 to 36 parts of halogenated alkane are added dropwise. After the addition is complete, the reaction is continued for 8 to 12 hours, and the isopropanol is removed by vacuum distillation to obtain a cage-type capture agent;

[0026] (2) The cage capture agent, demulsifier, cationic surfactant, small molecule auxiliary agent and water obtained in step (1) are weighed into a reaction container, mixed and stirred uniformly, and then heated. After the temperature stabilizes to 30-50° C., the mixture is stirred at a speed of 500-1500 rpm for 30-60 min to obtain a demulsifier composition for complex heavy oil produced fluid.

[0027] Furthermore, the dropping speed of ethylene glycol in step (12) is 1 drop per 5 to 10 seconds.

[0028] Furthermore, the alkaline aqueous solution in step (13) has a concentration of 0.1-2 mol / L, and the solute in the alkaline aqueous solution is one of sodium hydroxide, sodium bicarbonate, sodium carbonate, and ammonia water.

[0029] Furthermore, the general structural formula of the halogenated alkane in step (14) is C n H 2n+1 X, wherein n=8-14, X is one of Cl, Br, and I, preferably Br.

[0030] Effects of the invention: The demulsifier composition for complex heavy oil produced fluid and the preparation method thereof disclosed in the present invention have the following beneficial effects:

[0031] 1. The cage-type capture agent quickly diffuses and targets the high-valent alkylbenzene sulfonate on the interfacial membrane; at the same time, it works together with the cationic surfactant to reduce the repulsive force between droplets, interfacial viscosity and dilation modulus, which can reduce the viscosity of the oil phase and make the interfacial membrane more easily ruptured;

[0032] 2. Small molecule additives can increase the diffusion rate and have a synergistic effect with the targeted cage capture agent. Finally, the polyethylene polyamine-based demulsifier is adsorbed on the interfacial film and completely destroys the interfacial film. DETAILED DESCRIPTION

[0033] The specific embodiments of the present invention are described in detail below.

[0034] Example 1

[0035] A demulsifier composition for complex heavy oil produced fluid, comprising the following components in percentage by mass:

[0036] 5% cage capture agent, 30% demulsifier, 10% cationic surfactant, 5% small molecule additive, and the balance is water.

[0037] Furthermore, the caged capture agent is:

[0038]

[0039] Wherein R is n-octyl and X is Cl.

[0040] Furthermore, the demulsifier is ethylenediamine polyoxyethylene polyoxypropylene ether.

[0041] Furthermore, the cationic surfactant is an alkyl monoquaternary ammonium salt surfactant.

[0042] Furthermore, the alkyl monoquaternary ammonium salt surfactant is dodecyltrimethylammonium chloride.

[0043] Furthermore, the small molecule auxiliary agent is n-octane.

[0044] Example 2

[0045] A demulsifier composition for complex heavy oil produced fluid, comprising the following components in percentage by mass:

[0046] 10% cage capture agent, 40% demulsifier, 15% cationic surfactant, 15% small molecule additive, and the balance is water.

[0047] Furthermore, the caged capture agent is a mixture of the following compounds in equal molar ratios:

[0048]

[0049] Wherein R, R1, and R2 are all n-tetradecyl, and X is Br.

[0050] Furthermore, the demulsifier is diethylenetriamine polyoxyethylene polyoxypropylene ether.

[0051] Furthermore, the cationic surfactant is a mixture of equimolar gemini quaternary ammonium surfactants and triquaternary ammonium surfactants.

[0052] Furthermore, the general formula of the gemini quaternary ammonium salt surfactant is:

[0053]

[0054] Wherein: y=3, n=10, m=12, and X is Cl.

[0055] Furthermore, the triquaternary ammonium salt surfactant is an alkyl fatty amine polyoxyethylene ether triquaternary ammonium salt, and its general formula is as follows:

[0056]

[0057] Wherein: n=10, p=5, q=6, and X is Cl.

[0058] Furthermore, the small molecule auxiliary agent is nonylphenol polyoxyethylene ether.

[0059] Example 3

[0060] A demulsifier composition for complex heavy oil produced fluid, comprising the following components in percentage by mass:

[0061] 8% cage capture agent, 35% demulsifier, 12% cationic surfactant, 8% small molecule additive, and the balance is water.

[0062] Furthermore, the caged capture agent is:

[0063]

[0064] Wherein R is n-nonyl and X is I.

[0065] Furthermore, the demulsifier is triethylenetetramine polyoxyethylene polyoxypropylene ether.

[0066] Furthermore, the cationic surfactant is a gemini quaternary ammonium salt surfactant.

[0067] Furthermore, the general formula of the gemini quaternary ammonium salt surfactant is:

[0068]

[0069] Wherein: y=2, n=8, m=8, and X is Br.

[0070] Furthermore, the small molecule auxiliary agent is n-heptane.

[0071] Example 4

[0072] The same as Example 1, the only difference is that the caged capture agent is different: the caged capture agent is

[0073]

[0074] Wherein R1 is n-undecyl, R2 is n-tetradecyl, and X is Br.

[0075] Example 5

[0076] The same as Example 1, the only difference is that the caged capture agent is different: the caged capture agent is

[0077]

[0078] Wherein R1 is n-decyl, R2 is isotetradecyl, and X is Br.

[0079] Examples 6 to 24

[0080] The same as Example 1, the only difference is that the demulsifier is different

[0081]

[0082]

[0083] Examples 25 to 35

[0084] It is roughly the same as Example 1, except that:

[0085] The cationic surfactant is an alkyl monoquaternary ammonium salt surfactant, which is different from that in Example 1:

[0086]

[0087]

[0088] Example 36

[0089] The method is substantially the same as Example 1, except that the cationic surfactant is a gemini quaternary ammonium salt surfactant, and the general formula of the gemini quaternary ammonium salt surfactant is:

[0090]

[0091] Wherein: y=2, n=8, m=8, and X is Cl.

[0092] Example 37

[0093] The method is substantially the same as Example 1, except that the cationic surfactant is a gemini quaternary ammonium salt surfactant, and the general formula of the gemini quaternary ammonium salt surfactant is:

[0094]

[0095] Wherein: y=4, n=16, m=16, and X is Br.

[0096] Example 38

[0097] The method is substantially the same as Example 1, except that the cationic surfactant is a gemini quaternary ammonium salt surfactant, and the general formula of the gemini quaternary ammonium salt surfactant is:

[0098]

[0099] Wherein: y=3, n=14, m=12, and X is 1.

[0100] Example 39

[0101] The method is roughly the same as Example 1, except that the cationic surfactant is a triquaternary ammonium salt surfactant, and the triquaternary ammonium salt surfactant is an alkyl fatty amine polyoxyethylene ether triquaternary ammonium salt, and its general formula is as follows:

[0102]

[0103] Wherein: n=8, p=4, q=4, X is Cl.

[0104] Example 40

[0105] The method is roughly the same as Example 1, except that the cationic surfactant is a triquaternary ammonium salt surfactant, and the triquaternary ammonium salt surfactant is an alkyl fatty amine polyoxyethylene ether triquaternary ammonium salt, and its general formula is as follows:

[0106]

[0107] Wherein: n=16, p=7, q=7, and X is Br.

[0108] Example 41

[0109] The method is roughly the same as Example 1, except that the cationic surfactant is a triquaternary ammonium salt surfactant, and the triquaternary ammonium salt surfactant is an alkyl fatty amine polyoxyethylene ether triquaternary ammonium salt, and its general formula is as follows:

[0110]

[0111] Wherein: n=10, p=6, q=5, and X is 1.

[0112] Examples 42 to 48

[0113] The process is similar to Example 1, except that the small molecule additives are different:

[0114]

[0115] Example 49

[0116] A method for preparing a demulsifier composition for complex heavy oil produced fluid comprises the following steps, calculated by weight:

[0117] (1 Preparation of caged capture agent

[0118] (11) Add 115 g of amino-β-cyclodextrin to a reaction vessel (e.g., a flask), add 100 g of distilled water, stir, heat, and reflux with cold water, with the heating temperature stabilized at 40°C. After passing nitrogen for 40 minutes, close the nitrogen valve to stop the nitrogen flow;

[0119] (12) 1 g of urea peroxide and 2 g of ascorbic acid were added to the reaction vessel, and then 9 g of ethylene glycol was added dropwise at a rate of 1 drop per 10 seconds. 2 g of ethylene glycol was added dropwise and reacted for 30 min. 2 g of ethylene glycol was added dropwise and reacted for 30 min until all the ethylene glycol was added dropwise. The reaction was continued for 4 hours to obtain an intermediate reaction system.

[0120] (13) Adding alkaline aqueous solution to the intermediate reaction system, adjusting the pH value to neutral, then vacuum distilling to remove water, and drying the sample to obtain the intermediate product;

[0121] (14) Add 100 g of isopropanol to the intermediate product obtained in step (13) to dissolve it, then add 0.5 g of potassium iodide, stir and heat to 70°C, reflux with cold water, and dropwise add 18 g of 1-bromooctylalkane. After the dropwise addition is complete, continue the reaction for 12 h, and remove the isopropanol by distillation under reduced pressure to obtain a cage-type capture agent;

[0122] (2) The cage capture agent, demulsifier, cationic surfactant, small molecule auxiliary agent and water obtained in step (1) are weighed separately into a reaction container, mixed and stirred uniformly, and then heated. After the temperature stabilizes to 30° C., the mixture is stirred at a speed of 1500 rpm for 30 minutes to obtain a demulsifier composition for complex heavy oil produced fluid.

[0123] Furthermore, the alkaline aqueous solution in step (13) has a concentration of 0.1 / L, and the solute in the alkaline aqueous solution is sodium carbonate.

[0124] Furthermore, the demulsifier is diethylenetriamine polyoxyethylene polyoxypropylene ether.

[0125] Furthermore, the cationic surfactant is pentadecyltrimethylammonium chloride.

[0126] Furthermore, the small molecule auxiliary agent is isopropyl alcohol.

[0127] Example 50

[0128] A method for preparing a demulsifier composition for complex heavy oil produced fluid comprises the following steps, calculated by weight:

[0129] (1) Preparation of caged capture agents

[0130] (11) Add 120 g of amino-β-cyclodextrin to a reaction flask, add 100 g of distilled water, stir and heat, reflux with cold water, and stabilize the heating temperature at 50°C. After passing nitrogen for 20 minutes, close the nitrogen valve;

[0131] (12) 0.5 g of urea peroxide and 1.5 g of ascorbic acid were added to a reaction vessel, and 16 g of ethylene glycol was added dropwise at a rate of 1 drop per 5 seconds. 2 g of ethylene glycol was added dropwise and reacted for 30 min. 2 g of ethylene glycol was added dropwise and reacted for 30 min until the ethylene glycol was completely added. The reaction was continued for 4 hours to obtain an intermediate reaction system.

[0132] (13) adding an alkaline aqueous solution to the intermediate reaction system obtained in step (12), adjusting the pH value to neutral, and then removing water by vacuum distillation to obtain an intermediate product;

[0133] (14) Add 100 g of isopropanol to the intermediate product obtained in step (13) to dissolve it, then add 1 g of potassium iodide, stir, heat to 90°C, and reflux with cold water. Add 26 g of 1-bromododecane dropwise. After the addition is complete, continue the reaction for 10 h. Remove the isopropanol by distillation under reduced pressure. After the sample is dried, the cage-type capture agent is obtained.

[0134] (2) The cage capture agent, demulsifier, cationic surfactant, small molecule auxiliary agent and water obtained in step (1) are weighed into a reaction container respectively, mixed and stirred uniformly, and then heated. After the temperature stabilizes to 50° C., the mixture is stirred at a speed of 500 rpm for 60 min to obtain a demulsifier composition for complex heavy oil produced fluid.

[0135] Furthermore, the alkaline aqueous solution in step (13) has a concentration of 2 mol / L, and the solute in the alkaline aqueous solution is sodium hydroxide.

[0136] Furthermore, the demulsifier is hexaethylene heptamine polyoxypropylene polyoxyethylene polyoxypropylene ether.

[0137] Furthermore, the cationic surfactant is pentadecyltrimethylammonium chloride.

[0138] Furthermore, the small molecule auxiliary agent is n-octane.

[0139] Example 51

[0140] A method for preparing a demulsifier composition for complex heavy oil produced fluid comprises the following steps, calculated by weight:

[0141] (1) Preparation of caged capture agents

[0142] (11) Add 115 g of amino-β-cyclodextrin to a reaction flask, add 100 g of distilled water, stir and heat, reflux with cold water, and stabilize the heating temperature at 60°C. After nitrogen is passed for 30 minutes, close the nitrogen valve;

[0143] (12) Add 0.5 g of urea peroxide and 1.2 g of ascorbic acid to the reaction vessel, and add 14 g of ethylene glycol dropwise at a rate of 1 drop per 6 seconds. Add 2 g dropwise and react for 30 min. Continue to add 2 g dropwise and react for 30 min until all the ethylene glycol is added. Continue to react for 4 hours to obtain an intermediate reaction system.

[0144] (13) adding an alkaline aqueous solution to the intermediate reaction system obtained in step (12) to adjust the pH value to neutral, then removing water by vacuum distillation, and drying the sample to obtain an intermediate product;

[0145] (14) Add 100 g of isopropanol to the intermediate product obtained in step (13) to dissolve it, then add 2 g of potassium iodide, stir, heat to 85°C, and reflux with cold water. Add 28 g of 1-bromotetradecane dropwise. After the addition is complete, continue the reaction for 8 h. Remove the isopropanol by distillation under reduced pressure. After the sample is dried, the cage-type capture agent is obtained.

[0146] (2) Weigh the cage capture agent, demulsifier, cationic surfactant, small molecule auxiliary agent and water obtained in step (1) into the reaction container respectively, with the mass ratio of 8:40:12:5:35;

[0147] The mixture was mixed and stirred uniformly, and then heated. After the temperature was stabilized at 45° C., the mixture was stirred at a speed of 800 rpm for 40 minutes to obtain a demulsifier composition for complex heavy oil produced fluid.

[0148] Furthermore, the alkaline aqueous solution in step (13) has a concentration of 2 mol / L, and the solute in the alkaline aqueous solution is sodium bicarbonate.

[0149] Furthermore, the demulsifier is a mixture of diethylenetriamine polyoxyethylene polyoxypropylene ether and tetraethylenepentamine polyoxypropylene polyoxyethylene polyoxypropylene ether, and the mass ratio of the two is 1:3.

[0150] Furthermore, the cationic surfactant is a mixture of an alkyl monoquaternary ammonium salt surfactant, a gemini quaternary ammonium salt surfactant, and a triquaternary ammonium salt surfactant, and the mass ratio of the three is 2:5:5.

[0151] Furthermore, the alkyl monoquaternary ammonium salt surfactant is hexadecyltrimethylammonium chloride.

[0152] Furthermore, the general formula of the gemini quaternary ammonium salt surfactant is:

[0153]

[0154] Wherein: y=3, n=8, m=814, and X is Cl.

[0155] Furthermore, the triquaternary ammonium salt surfactant is an alkyl fatty amine polyoxyethylene ether triquaternary ammonium salt, and its general formula is as follows:

[0156]

[0157] Wherein: n=12, p=5, q=5, and X is Br.

[0158] Furthermore, the small molecule auxiliary agent is nonylphenol polyoxyethylene ether.

[0159] Example 52

[0160] A method for preparing a demulsifier composition for complex heavy oil produced fluid comprises the following steps, calculated by weight:

[0161] (1) Preparation of caged capture agents

[0162] (11) Add 125 g of diethylenetriamine-β-cyclodextrin to a reaction flask, add 100 g of distilled water, stir and heat, reflux with cold water, and stabilize the heating temperature at 30°C. After passing nitrogen for 30 minutes, close the nitrogen valve;

[0163] (12) 1 g of urea peroxide and 3 g of ascorbic acid were then added to the reaction vessel, and 28 g of ethylene glycol was added dropwise at a rate of 1 drop per 10 seconds. 2 g of ethylene glycol was added dropwise and reacted for 30 min. 2 g of ethylene glycol was added dropwise and reacted for 30 min until all the ethylene glycol was added dropwise. The reaction was continued for 4 hours to obtain an intermediate reaction system.

[0164] (13) adding an alkaline aqueous solution to the intermediate reaction system obtained in step (12) to adjust the pH value to neutral, then removing water by vacuum distillation, and drying the sample to obtain an intermediate product;

[0165] (14) 100 g of isopropyl alcohol was added to the intermediate product obtained in step (13) to dissolve the mixture, followed by addition of 4 g of potassium iodide. The mixture was stirred, heated to 80°C, and refluxed with cold water. 36 g of 1-bromohexadecane was added dropwise. After the addition was complete, the reaction was continued for 10 h. The isopropyl alcohol was removed by distillation under reduced pressure. After the sample was dried, a cage-type capture agent was obtained.

[0166] (2) The cage capture agent, demulsifier, cationic surfactant, small molecule auxiliary agent and water obtained in step (1) are weighed into a reaction container respectively, mixed and stirred uniformly, and then heated. After the temperature stabilizes to 45° C., the mixture is stirred at a speed of 800 rpm for 40 minutes to obtain a demulsifier composition for complex heavy oil produced fluid.

[0167] Furthermore, the alkaline aqueous solution in step (13) has a concentration of 0.5 mol / L, and the solute in the alkaline aqueous solution is sodium bicarbonate.

[0168] Furthermore, the demulsifier is diethylenetriamine polyoxyethylene polyoxypropylene polyoxyethylene ether.

[0169] Furthermore, the cationic surfactant is tridecyltrimethylammonium bromide.

[0170] Furthermore, the small molecule auxiliary agent is n-heptane.

[0171] Example 53

[0172] A method for preparing a demulsifier composition for complex heavy oil produced fluid comprises the following steps, calculated by weight:

[0173] (1) Preparation of caged capture agents

[0174] (11) Add 125 g of diethylenetriamine-β-cyclodextrin to a reaction flask, add 100 g of distilled water, stir, heat, and reflux with cold water. Keep the heating temperature stable at 40°C. Flow nitrogen for 30 minutes and then close the nitrogen valve.

[0175] (12) 0.8 g of urea peroxide and 1.5 g of ascorbic acid were then added to the reaction vessel, and 20 g of ethylene glycol was added dropwise at a rate of 1 drop per 5 seconds. 2 g of ethylene glycol was added dropwise and reacted for 30 min. 2 g of ethylene glycol was added dropwise and reacted for 30 min until all the ethylene glycol was added dropwise. The reaction was continued for 3 hours to obtain an intermediate reaction system.

[0176] (13) adding an alkaline aqueous solution to the intermediate reaction system obtained in step (12) to adjust the pH value to neutral, then removing water by vacuum distillation, and drying the sample to obtain an intermediate product;

[0177] (14) 100 g of isopropanol was added to the intermediate product obtained in step (13) to dissolve the mixture, followed by the addition of 5 g of potassium iodide. The mixture was stirred, heated to 80°C, and refluxed with cold water. 34 g of 1-bromopentadecane was added dropwise. After the addition was complete, the reaction was continued for 8 h. The isopropanol was removed by distillation under reduced pressure. After the sample was dried, a cage-type capture agent was obtained.

[0178] (2) Weigh the cage capture agent, demulsifier, cationic surfactant, small molecule auxiliary agent and water obtained in step (1) into the reaction container respectively, with the mass ratio of 10:35:10:5:40;

[0179] The mixture was mixed and stirred uniformly, and then heated. After the temperature was stabilized at 40° C., the mixture was stirred at a speed of 1000 rpm for 45 minutes to obtain a demulsifier composition for complex heavy oil produced fluid.

[0180] Furthermore, the alkaline aqueous solution in step (13) has a concentration of 1 mol / L, and the solute in the alkaline aqueous solution is sodium hydroxide.

[0181] Furthermore, the demulsifier is pentaethylene hexamine polyoxyethylene polyoxypropylene ether.

[0182] Furthermore, the cationic surfactant is a triquaternary ammonium salt surfactant, and its general formula is as follows:

[0183]

[0184] Wherein: n=14, p=5, q=5, X is Cl5.

[0185] Furthermore, the small molecule auxiliary agent is petroleum ether.

[0186] Example 54

[0187] A method for preparing a demulsifier composition for complex heavy oil produced fluid comprises the following steps, calculated by weight:

[0188] (1) Preparation of caged capture agents

[0189] (11) Add 125 g of diethylenetriamine-β-cyclodextrin to a reaction flask, add 100 g of distilled water, stir and heat, reflux with cold water, and stabilize the heating temperature at 50°C. After passing nitrogen for 30 minutes, close the nitrogen valve;

[0190] (12) Add 0.5 g of urea peroxide and 1.0 g of ascorbic acid to a reaction vessel, and then dropwise add 18 g of ethylene glycol. Add 1 drop of ethylene glycol every 6 seconds, and allow to react for 30 minutes. Continue to dropwise add 2 g of ethylene glycol and allow to react for 30 minutes until all the ethylene glycol has been added. Continue the reaction for 5 hours to obtain an intermediate reaction system.

[0191] (13) adding an alkaline aqueous solution to the intermediate reaction system obtained in step (12) to adjust the pH value to neutral, then removing water by vacuum distillation, and drying the sample to obtain an intermediate product;

[0192] (14) 100 g of isopropanol was added to the intermediate product obtained in step (13) to dissolve the mixture, followed by the addition of 3 g of potassium iodide. The mixture was stirred, heated to 80°C, and refluxed with cold water. 36 g of 1-bromododecane was added dropwise. After the addition was complete, the reaction was continued for 12 h. The isopropanol was removed by distillation under reduced pressure. After the sample was dried, a cage-type capture agent was obtained.

[0193] (2) The cage capture agent, demulsifier, cationic surfactant, small molecule auxiliary agent and water obtained in step (1) are weighed separately into a reaction container, mixed and stirred uniformly, and then heated. After the temperature stabilizes to 30° C., the mixture is stirred at a speed of 1500 rpm for 30 minutes to obtain a demulsifier composition for complex heavy oil produced fluid.

[0194] Furthermore, the alkaline aqueous solution in step (13) has a concentration of 1 mol / L, and the solute in the alkaline aqueous solution is ammonia water.

[0195] Furthermore, the demulsifier is triethylenetetramine polyoxyethylene polyoxypropylene polyoxyethylene ether.

[0196] Furthermore, the cationic surfactant is dodecyltrimethylammonium chloride.

[0197] Furthermore, the small molecule auxiliary agent is ethanol.

[0198] Effect of demulsifier composition on microscopic properties of emulsion droplets

[0199] An appropriate amount of water was added to the demulsifier composition prepared in Example 53 to prepare an aqueous solution with a concentration of 100 mg / L (the solute is the mass of the demulsifier composition).

[0200] The effects of the above demulsifiers and the on-site demulsifiers of the same concentration on the microscopic properties of the emulsion droplets were tested on the produced fluid that was difficult to demulsify on site. The results are shown in the following table:

[0201] Table 1 Microscopic properties of emulsion droplets in different systems

[0202]

[0203] The data in the table show that the addition of caged scavengers can reduce interfacial viscosity and dilational modulus, lowering oil phase viscosity and making the interfacial film more susceptible to rupture. Furthermore, small molecule additives can increase diffusion speed, creating a synergistic effect with caged scavengers.

[0204] The test revealed that, compared with the original on-site demulsifier, the repulsive force between emulsion droplets of the demulsifier composition for complex heavy oil produced fluid prepared in Example 7 was reduced to 54% of the original value.

[0205] Evaluation effect of indoor demulsification and dehydration rate of demulsifier

[0206] Due to the increase in oil well production measures at Joint Station A and Joint Station B, the produced fluid was severely emulsified and the stability of the emulsion interface film increased. The existing demulsifier could not meet the on-site dehydration requirements. According to the on-site conditions, the demulsifier composition of the present invention was added.

[0207] The water content of crude oil decreases to varying degrees after treatment at each level of the joint station. When it reaches the crude oil export point, the water content of crude oil is ≤1.5%, meeting the export requirements.

[0208] Table 2 Statistics of field application effects of the present invention and comparative demulsifiers

[0209]

[0210] Table 2 shows the demulsification and dehydration results of the same produced fluid, with the addition of the same concentrations of the comparative demulsifier and the present invention. Table 2 shows that after each stage of the treatment process, the water content of the crude oil emulsion containing the present invention is 5%-10% lower than that of the comparative demulsifier, and the water content of the exported oil has dropped to below 1.5%, meeting the requirements for crude oil export.

[0211] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments, and various modifications can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention.

Claims

1. A demulsifier composition for complex heavy oil produced fluid, characterized in that: In terms of mass percentage, it is composed of the following components: 5% to 10% cage capture agent, 30% to 40% demulsifier, 10% to 15% cationic surfactant, 5% to 15% small molecule additive, the balance is water, wherein: The caged capture agent is at least one of the following four types of compounds: Wherein: R, R1, and R2 are normal or isomeric alkyl groups with 8 to 14 carbon atoms; X is one of Cl, Br, and I; The small molecule auxiliary agent is one or more of n-octane, nonylphenol polyoxyethylene ether, n-heptane, ethanol, isopropanol, and petroleum ether.

2. A demulsifier composition for complex heavy oil produced fluid according to claim 1, characterized in that: The demulsifier is ethylenediamine polyoxyethylene polyoxypropylene ether, diethylenetriamine polyoxyethylene polyoxypropylene ether, triethylenetetramine polyoxyethylene polyoxypropylene ether, tetraethylenepentamine polyoxyethylene polyoxypropylene ether, pentaethylenehexamine polyoxyethylene polyoxypropylene ether, hexaethyleneheptamine polyoxyethylene polyoxypropylene ether, ethylenediamine polyoxyethylene polyoxypropylene polyoxyethylene ether, diethylenetriamine polyoxyethylene polyoxypropylene polyoxyethylene ether, triethylenetetramine polyoxyethylene polyoxypropylene polyoxyethylene ether, tetraethylenepentamine polyoxyethylene polyoxypropylene One or more of ethylene polyoxyethylene ether, pentaethylene hexamine polyoxyethylene polyoxypropylene polyoxyethylene ether, hexaethylene heptamine polyoxyethylene polyoxypropylene polyoxyethylene ether, ethylenediamine polyoxypropylene polyoxyethylene polyoxypropylene ether, diethylenetriamine polyoxypropylene polyoxyethylene polyoxypropylene ether, triethylenetetramine polyoxypropylene polyoxyethylene polyoxypropylene ether, tetraethylenepentamine polyoxypropylene polyoxyethylene polyoxypropylene ether, pentaethylenehexamine polyoxypropylene polyoxyethylene polyoxypropylene ether, and hexaethylene heptamine polyoxypropylene polyoxyethylene polyoxypropylene ether.

3. A demulsifier composition for complex heavy oil produced fluid according to claim 1, characterized in that: The cationic surfactant is one or more of an alkyl monoquaternary ammonium salt surfactant, a gemini quaternary ammonium salt surfactant, and a triquaternary ammonium salt surfactant.

4. A demulsifier composition for complex heavy oil produced fluid according to claim 3, characterized in that: The alkyl monoquaternary ammonium salt surfactant is one or more of dodecyltrimethylammonium chloride, tridecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, pentadecyltrimethylammonium chloride, hexadecyltrimethylammonium chloride, dodecyltrimethylammonium bromide, tridecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide, pentadecyltrimethylammonium bromide, and hexadecyltrimethylammonium bromide.

5. A demulsifier composition for complex heavy oil produced fluid according to claim 3, characterized in that: The general formula of the gemini quaternary ammonium salt surfactant is: Wherein: y=2-4, n=8-16, m=8-16, and X is one of Cl, Br, and I.

6. A demulsifier composition for complex heavy oil produced fluid according to claim 3, characterized in that: The triquaternary ammonium salt surfactant is an alkyl fatty amine polyoxyethylene ether triquaternary ammonium salt, and its general formula is as follows: Wherein: n=8-16, p=4-7, q=4-7, and X is one of Cl, Br, and I.

7. A method for preparing the demulsifier composition for complex heavy oil produced fluid according to claim 1, characterized in that: By mass, the following steps are included (1) Preparation of caged capture agent: (11) Add 115-125 parts of amino-β-cyclodextrin or diethylenetriamine-β-cyclodextrin to a reaction vessel, add 100 parts of distilled water, stir and heat, reflux with cold water, control the heating temperature at 30-60°C, and then stop the nitrogen flow after passing nitrogen for 20-40 minutes; (12) adding 0.5 to 1 parts of urea peroxide and 1 to 3 parts of ascorbic acid to the reaction vessel, and then dropwise adding 9 to 28 parts of ethylene glycol to the reaction vessel. After the dropwise addition is completed, the reaction is continued for 3 to 5 hours to obtain an intermediate reaction system; (13) adding an alkaline aqueous solution to the intermediate reaction system obtained in step (12), adjusting the pH value of the intermediate reaction system to neutral, and then vacuum distilling to remove water to obtain an intermediate product; (14) The intermediate product obtained in step (13) is dissolved in 100 parts of isopropanol, and then 0.5 to 5 parts of potassium iodide are added, stirred and heated to 70 to 90°C, refluxed with cold water, and then 18 to 36 parts of halogenated alkane are added dropwise. After the addition is complete, the reaction is continued for 8 to 12 hours, and the isopropanol is removed by vacuum distillation to obtain a cage-type capture agent; (2) The cage capture agent, demulsifier, cationic surfactant, small molecule auxiliary agent and water obtained in step (1) are weighed into a reaction container, mixed and stirred uniformly, and then heated. After the temperature stabilizes to 30-50° C., the mixture is stirred at a speed of 500-1500 rpm for 30-60 min to obtain a demulsifier composition for complex heavy oil produced fluid.

8. The method for preparing a demulsifier composition for complex heavy oil produced fluid according to claim 7, wherein: The dropping speed of ethylene glycol in step (12) is 1 drop per 5 to 10 seconds.

9. The method for preparing a demulsifier composition for complex heavy oil produced fluid according to claim 7, wherein: The alkaline aqueous solution in step (13) has a concentration of 0.1-2 mol / L, and the solute in the alkaline aqueous solution is one of sodium hydroxide, sodium bicarbonate, sodium carbonate, and ammonia water.

10. The method for preparing a demulsifier composition for complex heavy oil produced fluid according to claim 7, characterized in that: The general structural formula of the halogenated alkane in step (14) is C n H 2n+1 X, wherein n=8 to 14, and X is one of Cl, Br, and I.

11. The method for preparing a demulsifier composition for complex heavy oil produced fluid according to claim 10, wherein: The general structural formula of the halogenated alkane in step (14) is C n H 2n+1 X, wherein n=8-14, and X is Br.

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