A compound demulsifier and a preparation method thereof

Abstract

The application discloses a compound demulsifier and a preparation method thereof, and belongs to the technical field of oilfield development. The compound demulsifier comprises the following components in parts by weight: 25-40 parts of sodium dioctyl sulfosuccinate, 20-33 parts of alkyl bromopyridine, 12-20 parts of esterified non-ionic polyether demulsifier, 5-10 parts of flocculant, 3-8 parts of oxidant, 1-5 parts of dispersant and 55-70 parts of alcohol solvent; wherein the molecular weight of the esterified non-ionic polyether demulsifier is 4200-6000. The compound demulsifier is prepared by compounding sodium dioctyl sulfosuccinate, alkyl bromopyridine and esterified non-ionic polyether demulsifier, and is used for demulsification of shale oil emulsion, so that the multilayer colloid interface film is layer by layer destroyed, and efficient demulsification is realized.

Description

Technical Field

[0001] This application relates to a compound demulsifier and its preparation method, belonging to the field of oilfield development technology. Background Technology

[0002] Shale oil is an important unconventional petroleum resource, widely distributed with enormous exploration and development potential, and is expected to replace conventional crude oil resources to some extent. However, due to the unique occurrence state of shale oil, a large amount of shale oil-water emulsion is generated during the extraction process. Furthermore, the high level of naturally occurring interfacial active components in shale oil leads to a stable oil-water interface structure, making demulsification difficult and hindering subsequent processing and utilization.

[0003] Chemical demulsification is a widely used method in recent years. It involves adding a demulsifier to alter the interfacial properties of the emulsion system, making it unstable and thus achieving demulsification. For example, Chinese invention patent CN110330999B discloses a highly efficient compound crude oil demulsifier composed of the following parts by weight: 15-20 parts phenolic resin, 4-7 parts sodium dodecyl sulfate, 1-2 parts phenolic amine resin polyether, 6-9 parts solvent, 1-2 parts propylene oxide, 1-3 parts sponge iron, 2-4 parts sponge nickel, and 1-2 parts fluorinated surfactant; it exhibits good demulsification performance on crude oil emulsions. However, this demulsifier's dehydration performance on shale oil is not ideal. Summary of the Invention

[0004] To address the aforementioned issues, a compound demulsifier and its preparation method are provided. By compounding sodium dioctyl succinate sulfonate, sodium dioctyl succinate sulfonate, and an esterified nonionic polyether demulsifier, shale oil emulsions are demulsified, achieving layer-by-layer destruction of multilayer colloidal interfacial films, thereby realizing highly efficient demulsification.

[0005] The technical solution adopted in this invention is as follows: According to another aspect of this application, a compound demulsifier is provided, comprising the following components in parts by weight: 25-40 parts of sodium dioctyl succinate sulfonate, 20-33 parts of alkyl bromide pyridine, 12-20 parts of esterified nonionic polyether demulsifier, 5-10 parts of flocculant, 3-8 parts of oxidant, 1-5 parts of dispersant, and 55-70 parts of alcohol solvent; The molecular weight of the esterified nonionic polyether demulsifier is 4200-6000.

[0006] Optionally, the weight ratio of sodium dioctyl succinate sulfonate, alkyl pyridine bromide, and esterified nonionic polyether demulsifier is (1.8-3):(1.2-2.5):1.

[0007] Optionally, the preparation method of the esterified nonionic polyether demulsifier includes: (1) Place the ethylene glycol block polyether into a reaction vessel, inject an inert gas, add an organic solvent, stir at 40-60℃ for 5-15 min, then add 0.7-1.2 wt% of the ethylene glycol block polyether catalyst, then pour 4-vinylbenzoic acid into the reaction vessel, stir at 120-140℃ for 7-9 h, remove the solvent by vacuum distillation to obtain the esterification intermediate; (2) Under an inert atmosphere, the esterification intermediate is dissolved in an organic solvent at 40-60°C, and an initiator of 0.5-2 wt% of the weight of the esterification intermediate is added. After stirring at 60-80°C for 5-7 h, the solvent is removed by vacuum distillation, and the esterified nonionic polyether demulsifier is collected.

[0008] Optionally, the molar ratio of 4-vinylbenzoic acid to ethylene glycol block polyether is (2-3):1; And / or, the molecular weight of the ethylene glycol block polyether is 2000-3800.

[0009] Optionally, the catalyst is p-toluenesulfonic acid; And / or, the initiator is benzoyl peroxide or azobisisobutyronitrile; And / or, the organic solvent is toluene or xylene.

[0010] Optionally, the alkyl pyridine bromide is 1-tetradecyl pyridine bromide and / or 1-octadecyl pyridine bromide.

[0011] Optionally, the flocculant is starch, chitosan, or sodium alginate; And / or, the oxidant is chlorine dioxide; And / or, the dispersant is Tween 80, sodium dodecyl sulfate, or sodium metasilicate; And / or, the alcohol solvent is methanol, ethanol, ethylene glycol or isopropanol.

[0012] According to another aspect of this application, a method for preparing any of the above-described compound demulsifiers is provided, comprising the following steps: By weight, dissolve 25-40 parts of sodium dioctyl succinate sulfonate, 20-33 parts of alkyl pyridine bromide, and 12-20 parts of esterified nonionic polyether demulsifier in 55-70 parts of alcohol solvent, then add 1-5 parts of dispersant, stir evenly, then add 5-10 parts of flocculant and 3-8 parts of oxidant, and continue stirring for 10-20 minutes to obtain the compound demulsifier.

[0013] Optionally, the stirring temperature is 30-50℃ and the stirring speed is 100-200 r / min.

[0014] The beneficial effects of this application include, but are not limited to: 1. The compound demulsifier and its preparation method of this application, sodium dioctyl succinate sulfonate, initially disrupts the stability of the oil-water interface of the emulsion through electrostatic interaction with oil droplets in the emulsion, thereby achieving demulsification; simultaneously, alkyl pyridine bromide interacts with the negatively charged parts of the emulsion through its positively charged pyridinium groups, neutralizing the surface charge of the droplets, reducing the repulsion between droplets, and promoting droplet aggregation, thus achieving oil-water separation; the two work together to break down the stable system of the emulsion through demulsification and aggregation; the esterified nonionic polyether demulsifier has stronger oil solubility and can replace the colloidal and asphaltic molecules at the oil-water interface with the interfacial water. The process involves hydrogen bond recombination of molecules and weakening the π-π stacking interactions between asphaltenes and gum molecules. This further breaks down the originally dense interfacial protective film and opens up mass transfer channels for water molecules at the interface, clearing obstacles for oil-water separation. On this basis, the oxidant decomposes residual organic matter, improving the treatment environment. Dispersants and alcohol solvents help avoid the formation of a stubborn "emulsion intermediate layer," resulting in a clear and uniform oil-water interface. The flocculant acts as a "bridging" agent after demulsification, aggregating destabilized micro-oil droplets and suspended particles for easy filtration and removal, further purifying the water. Sodium dioctyl succinate sulfonate, alkyl pyridine bromide, and esterified nonionic polyether demulsifier work synergistically, complementing the flocculant, oxidant, dispersant, and alcohol solvent, comprehensively compensating for the shortcomings of single agents in demulsification efficiency and separation effect, achieving highly efficient oil-water separation of shale oil emulsions.

[0015] 2. The compound demulsifier and its preparation method of this application introduce an aromatic structure through esterification of ethylene glycol block polyether with 4-vinylbenzoic acid, which effectively improves the lipophilicity and facilitates the diffusion of demulsifier molecules in shale oil. Through esterification and polymerization reactions, the demulsifier's ability and efficiency in reducing surface tension are improved, and its surface activity is increased. The esterified nonionic polyether demulsifier with strong lipophilicity and surface activity can efficiently penetrate the colloidal layer and diffuse to the oil-water interface, realizing the hydrogen bond recombination of interfacial water molecules and interfering with the π-π stacking interaction between colloidal molecules, thereby destroying the originally stable colloidal interfacial film, enhancing the mass transfer efficiency of water molecules between the interface, realizing the coalescence between water droplets, and thus achieving oil-water separation. Detailed Implementation

[0016] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0017] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0018] Example 1 A method for preparing a compound demulsifier includes the following steps: By weight, 25 parts of sodium dioctyl succinate sulfonate, 20 parts of 1-tetradecyl pyridine bromide and 12 parts of esterified nonionic polyether demulsifier were dissolved in 55 parts of methanol, and then 1 part of Tween 80 was added. The mixture was stirred evenly at 30°C and 100 r / min. Then, 5 parts of starch and 3 parts of chlorine dioxide were added, and the mixture was stirred for another 20 min to obtain the compound demulsifier. The preparation methods for esterified nonionic polyether demulsifiers include: (1) Ethylene glycol block polyether (molecular weight 2000) was placed in a reaction vessel, nitrogen was injected, toluene was added, and the mixture was stirred at 40°C for 15 min. Then, 0.7 wt% of p-toluenesulfonic acid was added to the ethylene glycol block polyether. Then, 4-vinylbenzoic acid was poured into the reaction vessel. The molar ratio of 4-vinylbenzoic acid to ethylene glycol block polyether was 2:1. The mixture was stirred at 120°C for 9 h. The solvent was removed by vacuum distillation to obtain the esterification intermediate. (2) Under a nitrogen atmosphere, the esterification intermediate was dissolved in toluene at 40°C, and 0.5 wt% of azobisisobutyronitrile was added. After stirring at 60°C for 7 h, the solvent was removed by vacuum distillation, and the esterified nonionic polyether demulsifier with a molecular weight of 4200 was collected.

[0019] Example 2 A method for preparing a compound demulsifier includes the following steps: By weight, 32 parts of sodium dioctyl succinate sulfonate, 13 parts of 1-tetradecyl pyridine bromide, 13 parts of 1-octadecyl pyridine bromide and 15 parts of esterified nonionic polyether demulsifier were dissolved in 63 parts of ethylene glycol, and then 3 parts of sodium dodecyl sulfate were added. The mixture was stirred evenly at 40°C and 150 r / min. Then, 8 parts of chitosan and 5 parts of chlorine dioxide were added, and the mixture was stirred for another 15 min to obtain the compound demulsifier. The preparation methods for esterified nonionic polyether demulsifiers include: (1) Ethylene glycol block polyether (molecular weight 3500) was placed in a reaction vessel, nitrogen gas was injected, xylene was added, and the mixture was stirred at 50°C for 10 min. Then, 1 wt% of p-toluenesulfonic acid was added to the ethylene glycol block polyether. Then, 4-vinylbenzoic acid was poured into the reaction vessel. The molar ratio of 4-vinylbenzoic acid to ethylene glycol block polyether was 2.5:1. The mixture was stirred at 130°C for 8 h. The solvent was removed by vacuum distillation to obtain the esterification intermediate. (2) Under a nitrogen atmosphere, the esterification intermediate was dissolved in xylene at 50°C, and 1.2 wt% of benzoyl peroxide was added. After stirring at 70°C for 6 h, the solvent was removed by vacuum distillation, and the esterified nonionic polyether demulsifier with a molecular weight of 5750 was collected.

[0020] Example 3 A method for preparing a compound demulsifier includes the following steps: By weight, 40 parts of sodium dioctyl succinate sulfonate, 33 parts of 1-octadecyl pyridine bromide and 20 parts of esterified nonionic polyether demulsifier are dissolved in 70 parts of isopropanol, then 5 parts of sodium metasilicate are added, and the mixture is stirred evenly at 50°C and 200 r / min. Then 10 parts of sodium alginate and 8 parts of chlorine dioxide are added, and the mixture is stirred for another 10 min to obtain the compound demulsifier. The preparation methods for esterified nonionic polyether demulsifiers include: (1) Ethylene glycol block polyether (molecular weight 3800) was placed in a reaction vessel, nitrogen was injected, toluene was added, and the mixture was stirred at 60°C for 5 min. Then, 1.2 wt% of p-toluenesulfonic acid was added to the ethylene glycol block polyether. Then, 4-vinylbenzoic acid was poured into the reaction vessel. The molar ratio of 4-vinylbenzoic acid to ethylene glycol block polyether was 3:1. The mixture was stirred at 140°C for 7 h. The solvent was removed by vacuum distillation to obtain the esterification intermediate. (2) Under a nitrogen atmosphere, the esterification intermediate was dissolved in toluene at 60°C, and 2 wt% of azobisisobutyronitrile (AIBN) was added. After stirring at 80°C for 5 h, the solvent was removed by vacuum distillation, and the esterified nonionic polyether demulsifier with a molecular weight of 6000 was collected.

[0021] Comparative Example 1 The difference from Example 2 is that sodium dioctyl succinate sulfonate is not disclosed.

[0022] Comparative Example 2 The difference from Example 2 is that 1-tetradecylpyridine bromide and 1-octadecylpyridine bromide are not disclosed.

[0023] Comparative Example 3 The difference from Example 2 is that the esterified nonionic polyether demulsifier is not disclosed.

[0024] Comparative Example 4 The difference from Example 2 is that the preparation method of the esterified nonionic polyether demulsifier is not disclosed, and the esterified nonionic polyether demulsifier is replaced with polyoxyethylene polyoxypropylene block polyether with a molecular weight of 5750.

[0025] Comparative Example 5 The difference from Example 2 is that sodium dioctyl succinate sulfonate is replaced with sodium petroleum sulfonate.

[0026] Comparative Example 6 The difference from Example 2 is that 1-tetradecylpyridine bromide and 1-octadecylpyridine bromide are replaced with dodecyl dimethyl ammonium chloride.

[0027] Comparative Example 7 The difference from Example 2 is that chlorine dioxide is replaced with hydrogen peroxide.

[0028] Comparative Example 8 The difference from Example 2 is that chitosan is replaced with polyaluminum chloride.

[0029] Comparative Example 9 The difference from Example 2 is that sodium dodecyl sulfate is replaced with polyethylene glycol.

[0030] Comparative Example 10 The difference from Example 2 is that 4-vinylbenzoic acid is replaced with methacrylic acid.

[0031] Comparative Example 11 The difference from Example 2 is that step (2) is not disclosed.

[0032] Comparative Example 12 The difference from Example 2 is that: 53 parts of sodium dioctyl succinate sulfonate, 20 parts of 1-tetradecyl pyridine bromide, 20 parts of 1-octadecyl pyridine bromide, and 5 parts of esterified nonionic polyether demulsifier.

[0033] Comparative Example 13 The difference from Example 2 is that the preparation method of the compound demulsifier includes the following steps: By weight, 32 parts of sodium dioctyl succinate sulfonate, 13 parts of 1-tetradecyl pyridine bromide, 13 parts of 1-octadecyl pyridine bromide, 15 parts of esterified nonionic polyether demulsifier, 3 parts of sodium dodecyl sulfate, 8 parts of chitosan and 5 parts of chlorine dioxide are dissolved in 63 parts of ethylene glycol and stirred evenly at 80°C and 50 r / min to obtain the compound demulsifier.

[0034] Demulsification performance test Shale oil from a block in the Shengli Oilfield was processed and dehydrated. The density of the dehydrated shale oil at 25℃ was 0.874 kg / m³. 3 The viscosity at 50℃ is 38.6 mPa·s, and the total water content is 0.5%. Shale oil and produced water are preheated at 40℃ for 10 min, and then... (The sentence is incomplete and requires more context to translate accurately.) （油） :V （水）The shale oil was mixed in a 6:4 ratio and stirred at 5000 rpm for 5 minutes to obtain a shale oil emulsion with a water content of 30%. The shale oil emulsion was placed in a glass tube, and 200 mg / L of the compound demulsifier from Examples 1-3 and Comparative Examples 1-13 was added. The mixture was shaken horizontally 100 times to ensure thorough mixing with the shale oil emulsion. The glass tube was then placed in a 60°C constant temperature water bath for oil-water separation. The amount of water removed was recorded at regular intervals, and the dehydration rate was calculated. The test results are shown in Table 1 below.

[0035] Table 1

[0036] As shown in Table 1, the compound demulsifier of this application has excellent demulsification performance, with synergistic effects among the components, and a dehydration rate of over 97.6%.

[0037] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A compound demulsifier, characterized in that, The product comprises the following components in parts by weight: 25-40 parts sodium dioctyl succinate sulfonate, 20-33 parts alkyl bromide pyridine, 12-20 parts esterified nonionic polyether demulsifier, 5-10 parts flocculant, 3-8 parts oxidant, 1-5 parts dispersant, and 55-70 parts alcohol solvent. The molecular weight of the esterified nonionic polyether demulsifier is 4200-6000. The preparation method of the esterified nonionic polyether demulsifier includes: (1) Place the ethylene glycol block polyether into a reaction vessel, inject an inert gas, add an organic solvent, stir at 40-60℃ for 5-15 min, then add 0.7-1.2 wt% of the ethylene glycol block polyether catalyst, then pour 4-vinylbenzoic acid into the reaction vessel, stir at 120-140℃ for 7-9 h, remove the solvent by vacuum distillation to obtain the esterification intermediate; (2) Under an inert atmosphere, the esterification intermediate is dissolved in an organic solvent at 40-60°C, and an initiator of 0.5-2 wt% of the weight of the esterification intermediate is added. After stirring at 60-80°C for 5-7 h, the solvent is removed by vacuum distillation, and the esterified nonionic polyether demulsifier is collected.

2. The compound demulsifier according to claim 1, characterized in that, The weight ratio of sodium dioctyl succinate sulfonate, alkyl pyridine bromide, and esterified nonionic polyether demulsifier is (1.8-3):(1.2-2.5):

1.

3. The compound demulsifier according to claim 1, characterized in that, The molar ratio of 4-vinylbenzoic acid to ethylene glycol block polyether is (2-3):1; And / or, the molecular weight of the ethylene glycol block polyether is 2000-3800.

4. The compound demulsifier according to claim 1, characterized in that, The catalyst is p-toluenesulfonic acid; And / or, the initiator is benzoyl peroxide or azobisisobutyronitrile; And / or, the organic solvent is toluene or xylene.

5. The compound demulsifier according to claim 1, characterized in that, The alkyl pyridine bromide is 1-tetradecyl pyridine bromide and / or 1-octadecyl pyridine bromide.

6. The compound demulsifier according to claim 1, characterized in that, The flocculant is starch, chitosan, or sodium alginate; And / or, the oxidant is chlorine dioxide; And / or, the dispersant is Tween 80, sodium dodecyl sulfate, or sodium metasilicate; And / or, the alcohol solvent is methanol, ethanol, ethylene glycol or isopropanol.

7. The method for preparing the compound demulsifier according to any one of claims 1-6, characterized in that, Includes the following steps: By weight, dissolve 25-40 parts of sodium dioctyl succinate sulfonate, 20-33 parts of alkyl pyridine bromide, and 12-20 parts of esterified nonionic polyether demulsifier in 55-70 parts of alcohol solvent, then add 1-5 parts of dispersant, stir evenly, then add 5-10 parts of flocculant and 3-8 parts of oxidant, and continue stirring for 10-20 minutes to obtain the compound demulsifier.

8. The method for preparing the compound demulsifier according to claim 7, characterized in that, The stirring temperature is 30-50℃ and the stirring speed is 100-200r / min.

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