Demulsifier for breaking oil-water transition zone for oil-gas gathering and transportation and preparation method thereof

Abstract

The invention belongs to the technical field of sewage treatment, and particularly relates to a demulsifier for breaking an oil-water transition zone for oil-gas gathering and transportation and a preparation method thereof. The preparation method comprises the following steps: adding (3-acryloyloxypropyl) tri (trimethylsiloxy) silane, diethyl allyl malonate, deionized water, nonylphenol polyoxyethylene ether, alkylphenol ether sodium sulfosuccinate and sodium dihydrogen phosphate into a first reactor, and stirring; 3-[(3-acrylamidopropyl) dimethylammonium] propionate, allyl alcohol polyoxyethylene ether and deionized water are added into a second reactor and heated to be dissolved; adding an initiator and sodium hydrogen sulfite into the first reactor, carrying out heating and heat preservation reaction, pouring the mixed solution in the second reactor, and continuously carrying out reaction, heating and heat preservation to obtain a viscous liquid; and drying and granulating the solution to obtain the demulsifier. The demulsifier disclosed by the invention has a good demulsification effect, a demulsified water phase is clear, and an oil-water interface is clear.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage treatment, and in particular relates to a demulsifier for breaking an oil-water transition zone for oil and gas gathering and transportation and a preparation method thereof. Background Art

[0002] In the process of oil and gas gathering and transportation, crude oil produced liquid usually exists in the form of oil-water emulsion. With the continuous deepening of oil field exploitation, major oil fields have successively entered the tertiary oil recovery stage. The produced crude oil has changed from the oil-in-water emulsion in the primary oil recovery stage to the water-in-oil emulsion, and the stability of the emulsion system has gradually increased.

[0003] In the oil and gas gathering and transportation system, the treatment of the oil-water transition zone is a key link. The oil-water transition zone usually contains a large number of small, dispersed oil and water droplets, which are wrapped by a layer of stable interfacial film, making oil-water separation extremely difficult. This stable interfacial film is often formed by the natural emulsifier components in crude oil, such as asphaltene, colloid, wax and other organic matter, and the chemical flooding agent added during the oil recovery process.

[0004] As oilfield development continues, the composition and properties of crude oil become more and more complex, and the difficulty of handling the oil-water transition zone also increases. Traditional demulsifiers often show problems such as poor adaptability, high demulsification temperature, and slow dehydration speed when dealing with such complex systems. Especially under low temperature conditions, conventional demulsifiers are difficult to effectively break the oil-water interface film, resulting in low oil-water separation efficiency, affecting the quality of crude oil transmission and the treatment capacity of downstream sewage treatment plants.

[0005] CN101113028A discloses a demulsifying purifier, characterized in that it is composed of the following raw materials in percentage by weight: 2% to 68% of sewage, 2% to 37% of polyferric sulfate, 5% to 45% of polyaluminium chloride, 6% to 57% of anhydrous calcium chloride, and 19% to 47% of ferric chloride; its preparation method is: put sewage, polyferric sulfate and polyaluminium chloride into a mixer, then pour in anhydrous calcium chloride and add 50% of water of the sum of the four raw materials, stir fully, stir at a speed of 60 revolutions per minute, ensure that the solid components are completely dissolved, and keep for 2-3 hours; then add ferric chloride and continue stirring, stirring at a speed of 50-80 revolutions per minute, for half an hour to 1 hour, stop the machine for 6-10 hours, filter and pack into the product packaging barrel. The use concentration of the agent during demulsification of the invention is 300-500mg / L, the dosage is large, the operation is cumbersome, and a large amount of scum will be generated, and a large amount of the agent will be left in the water body, causing secondary pollution.

[0006] CN109575984A discloses a crude oil demulsifier for normal low temperature, which consists of: 10-50% by mass of silicone polyether with a viscosity of 200-300mPa·s, an HLB value of 7-10, and a closed flash point greater than 60°C; and 50-90% by mass of a mixture of one or more as a solvent. The silicone polyether in the composition of the crude oil demulsifier has different structures and molecular weight distributions, and has a highly efficient oil-water demulsification effect. Siloxane has low surface tension, low cohesive energy, and low temperature sensitivity, and can achieve demulsification at a low temperature of 30°C. The amount added is reduced by more than 50% compared to the use of polyether surfactants alone, the dehydration rate is fast, the demulsification effect is good, and the overall cost is reduced. The crude oil dehydration rate of the demulsifier of the invention is only 40% in 120 minutes, which cannot meet production needs, and the dehydration effect needs to be improved. Summary of the invention

[0007] The present invention aims at the deficiencies of the existing technology and provides a demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation and a preparation method thereof. The demulsifier of the present invention has good demulsification effect, the water phase after demulsification is clear, and the oil-water interface is clear.

[0008] One of the purposes of the present invention is to disclose a demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation. The molecular formula of the demulsifier is as follows: Where: a=5000-50000; b = 1000-20000; c = 2500-50000; d = 2500-50000; n is a positive integer from 10 to 20.

[0009] Preferably, the viscosity average molecular weight of the demulsifier is 10,000,000-20,000,000.

[0010] Another object of the present invention is to provide a method for preparing a demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation, and the specific steps of the preparation method are as follows: (1) The first reactor and pipeline were purged with nitrogen for 8-10 minutes, (3-acryloxypropyl) tris(trimethylsiloxy) silane, diethyl allyl malonate, deionized water, nonylphenol polyoxyethylene ether, sodium salt of alkylphenol ether sulfosuccinate, and sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 3-[(3-acrylamidopropyl)dimethylammonium] propionate, allyl alcohol polyoxyethylene ether and deionized water into the second reactor and heat to dissolve; (3) Add initiator and sodium bisulfite to the first reactor, raise the temperature to 40-50°C, and keep the temperature to react. When the viscosity starts to rise, quickly pour the mixed solution in the second reactor into the reactor, continue the reaction for 0.5-2h, raise the temperature to 60-70°C, keep the temperature for 20-30min, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) The solution is dried and granulated to obtain a demulsifier.

[0011] In the present invention, preferably, based on 1 mol part of (3-acryloxypropyl)tris(trimethylsiloxy)silane, the amounts of allyl malonate diethyl ester, 3-[(3-acrylamidopropyl)dimethylammonium]propionate, and allyl alcohol polyoxyethylene ether are 0.2-0.4, 0.5-1, and 0.5-1 mol parts, respectively.

[0012] In the present invention, preferably, in step (1), the mass ratio of deionized water, nonylphenol polyoxyethylene ether, alkylphenol ether sodium sulfosuccinate, sodium dihydrogen phosphate and (3-acryloxypropyl) tris(trimethylsiloxy)silane is 3-5:0.2-0.5:0.1-0.2:0.1-0.2:1.

[0013] In the present invention, preferably, in step (2), the mass ratio of deionized water to (3-acryloxypropyl)tris(trimethylsiloxy)silane is 6-8:1.

[0014] In the present invention, preferably, in step (3), the mass ratio of the initiator, sodium bisulfite and (3-acryloxypropyl)tris(trimethylsiloxy)silane is 0.1-0.2:0.05-0.1:1.

[0015] In the present invention, preferably, in step (3), the initiator is one of sodium persulfate, potassium persulfate and ammonium persulfate.

[0016] The demulsifier synthesis reaction equation of the present invention is as follows: The demulsifier of the present invention is a polymer demulsifier with polyethylene as the main chain and various long-chain functional groups as side chains. Cationic quaternary ammonium salts neutralize charges with negatively charged emulsified droplets, reduce electrostatic repulsion between droplets, and make oil droplets aggregate and release to form oil droplets with large particle size, thereby achieving the purpose of demulsification; silane and siloxane molecules form a hydrophobic film at the oil-water interface, destroy the original emulsified film, and promote droplet aggregation by reducing interfacial tension; polyester molecules are adsorbed on the oil-water interface, destroy the stability of the interfacial film, thereby achieving flocculation and demulsification; the polyether segment has high flexibility and is curled in water, and the area of ​​the demulsifier monomolecule adsorbed on the interface increases, which affects the close arrangement of demulsifier molecules on the interface, and the ability to reduce the viscosity and interfacial elasticity of the oil-water interface also increases, thereby reducing the strength of the oil-water interface film, resulting in a shortened oil film life, accelerated film thinning speed, and increased dehydration rate of crude oil emulsion, thereby demulsification.

[0017] The demulsifier of the present invention has a good demulsification effect. For the emulsified oil of 52000 mg / L in the oil-water transition zone of gathering and transportation, when the concentration is 80 mg / L, the dehydration amount of 100 ml of emulsion reaches 89 ml or more in 90 minutes. The water phase after demulsification is clear, the oil content is less than 100 mg / L, and the oil-water interface is clear. DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with specific examples and with reference to data. It should be understood that these examples are only intended to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0019] Example 1 (1) The first reactor and pipeline were purged with nitrogen for 10 min, 50 mmol (3-acryloxypropyl) tris (trimethylsiloxy) silane, 10 mmol allyl diethyl malonate, 61.35 g deionized water, 4.09 g nonylphenol polyoxyethylene ether, 3.14 g alkylphenol ether sodium sulfosuccinate, and 2.045 g sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 25 mmol of 3-[(3-acrylamidopropyl)dimethylammonium] propionate, 50 mmol of allyl alcohol polyoxyethylene ether, and 122.7 g of deionized water into the second reactor and heat to dissolve; (3) Add 2.045g sodium persulfate and 1.02g sodium bisulfite to the first reactor, raise the temperature to 40°C, and keep the temperature to react. When the viscosity begins to rise, quickly pour the mixed solution in the second reactor into the reactor, continue the reaction for 2h, raise the temperature to 60°C, keep the temperature for 30min, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) The solution is dried and granulated to obtain a demulsifier.

[0020] Example 2 (1) The first reactor and pipeline were purged with nitrogen for 8 min, 50 mmol (3-acryloxypropyl) tris (trimethylsiloxy) silane, 10 mmol allyl diethyl malonate, 61.35 g deionized water, 4.09 g nonylphenol polyoxyethylene ether, 3.14 g alkylphenol ether sodium sulfosuccinate, and 2.045 g sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 25 mmol of 3-[(3-acrylamidopropyl)dimethylammonium] propionate, 50 mmol of allyl alcohol polyoxyethylene ether, and 122.7 g of deionized water into the second reactor and heat to dissolve; (3) Add 2.045g sodium persulfate and 1.02g sodium bisulfite to the first reactor, heat to 50°C, and keep warm for reaction. When the viscosity starts to rise, quickly pour the mixed solution in the second reactor into the reactor, continue to react for 0.5h, heat to 70°C, keep warm for 27min, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid. (4) The solution is dried and granulated to obtain a demulsifier.

[0021] Example 3 (1) The first reactor and pipeline were purged with nitrogen for 10 min, 50 mmol (3-acryloxypropyl) tris (trimethylsiloxy) silane, 20 mmol diethyl allyl malonate, 102.3 g deionized water, 10.2 g nonylphenol polyoxyethylene ether, 2.045 g alkylphenol ether sodium sulfosuccinate, and 4.09 g sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 50 mmol of 3-[(3-acrylamidopropyl)dimethylammonium] propionate, 25 mmol of allyl alcohol polyoxyethylene ether, and 163.6 g of deionized water into the second reactor and heat to dissolve; (3) Add 4.09 g of sodium persulfate and 1.02 g of sodium bisulfite to the first reactor, raise the temperature to 50°C, and keep the temperature to react. When the viscosity begins to rise, quickly pour the mixed solution in the second reactor into the reactor, continue the reaction for 1 hour, raise the temperature to 65°C, keep the temperature for 25 minutes, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) The solution is dried and granulated to obtain a demulsifier.

[0022] Example 4 (1) The first reactor and pipeline were purged with nitrogen for 10 min, 50 mmol (3-acryloxypropyl) tris (trimethylsiloxy) silane, 10 mmol allyl diethyl malonate, 81.3 g deionized water, 8.09 g nonylphenol polyoxyethylene ether, 3.14 g alkylphenol ether sodium sulfosuccinate, and 3.04 g sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 30 mmol of 3-[(3-acrylamidopropyl)dimethylammonium] propionate, 30 mmol of allyl alcohol polyoxyethylene ether, and 142.7 g of deionized water into the second reactor and heat to dissolve; (3) Add 3.04 g of sodium persulfate and 1.62 g of sodium bisulfite to the first reactor, raise the temperature to 45°C, and keep the temperature to react. When the viscosity begins to rise, quickly pour the mixed solution in the second reactor into the reactor, continue the reaction for 0.5 h, raise the temperature to 60°C, keep the temperature for 20 min, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) The solution is dried and granulated to obtain a demulsifier.

[0023] Example 5 (1) The first reactor and pipeline were purged with nitrogen for 10 min, and 50 mmol (3-acryloxypropyl) tris (trimethylsiloxy) silane, 15 mmol allyl diethyl malonate, 70.3 g deionized water, 8.09 g nonylphenol polyoxyethylene ether, 2.05 g alkylphenol ether sodium sulfosuccinate, and 3.2 g sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 38 mmol of 3-[(3-acrylamidopropyl)dimethylammonium] propionate, 40 mmol of allyl alcohol polyoxyethylene ether, and 150 g of deionized water into the second reactor and heat to dissolve; (3) Add 4g of sodium persulfate and 2g of sodium bisulfite to the first reactor, heat it to 50°C, and keep it warm for reaction. When the viscosity starts to rise, quickly pour the mixed solution in the second reactor into it, continue the reaction for 0.5h, heat it to 60°C, keep it warm for 20min, adjust the pH to 7-8 with sodium hydroxide solution, and obtain a viscous liquid; (4) The solution is dried and granulated to obtain a demulsifier.

[0024] Example 6 (1) The first reactor and pipeline were purged with nitrogen for 10 min, 50 mmol (3-acryloxypropyl) tris (trimethylsiloxy) silane, 10 mmol diethyl allyl malonate, 89 g deionized water, 10 g nonylphenol polyoxyethylene ether, 4.09 g alkylphenol ether sodium sulfosuccinate, and 4.09 g sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 29 mmol 3-[(3-acrylamidopropyl)dimethylammonium] propionate, 45 mmol allyl alcohol polyoxyethylene ether, and 152 g deionized water into the second reactor and heat to dissolve; (3) Add 3.5g of sodium persulfate and 1.8g of sodium bisulfite to the first reactor, heat it to 43°C, and keep it warm for reaction. When the viscosity starts to rise, quickly pour the mixed solution in the second reactor into it, continue to react for 0.5h, heat it to 68°C, keep it warm for 30min, adjust the pH to 7-8 with sodium hydroxide solution, and obtain a viscous liquid; (4) The solution is dried and granulated to obtain a demulsifier.

[0025] Example 7 (1) The first reactor and pipeline were purged with nitrogen for 9 minutes, 50 mmol (3-acryloxypropyl) tris (trimethylsiloxy) silane, 18 mmol allyl diethyl malonate, 92 g deionized water, 7.8 g nonylphenol polyoxyethylene ether, 2.8 g alkylphenol ether sodium sulfosuccinate, and 2.9 g sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 31 mmol of 3-[(3-acrylamidopropyl)dimethylammonium] propionate, 36 mmol of allyl alcohol polyoxyethylene ether, and 137.7 g of deionized water into the second reactor and heat to dissolve; (3) Add 3.6 g of sodium persulfate and 1.6 g of sodium bisulfite to the first reactor, raise the temperature to 48 °C, and keep the temperature to react. When the viscosity begins to rise, quickly pour the mixed solution in the second reactor into the reactor, continue the reaction for 1.5 h, raise the temperature to 63 °C, keep the temperature for 30 min, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) The solution is dried and granulated to obtain a demulsifier.

[0026] Example 8 (1) The first reactor and pipeline were purged with nitrogen for 8 min, 50 mmol (3-acryloxypropyl) tris (trimethylsiloxy) silane, 17 mmol allyl diethyl malonate, 91.3 g deionized water, 9.09 g nonylphenol polyoxyethylene ether, 3.84 g alkylphenol ether sodium sulfosuccinate, and 3.04 g sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 45 mmol of 3-[(3-acrylamidopropyl)dimethylammonium] propionate, 35 mmol of allyl alcohol polyoxyethylene ether, and 142.7 g of deionized water into the second reactor and heat to dissolve; (3) Add 3.5g of sodium persulfate and 1.5g of sodium bisulfite to the first reactor, heat it to 50°C, and keep it warm for reaction. When the viscosity starts to rise, quickly pour the mixed solution in the second reactor into it, continue the reaction for 2h, heat it to 65°C, keep it warm for 30min, adjust the pH to 7-8 with sodium hydroxide solution, and obtain a viscous liquid; (4) The solution is dried and granulated to obtain a demulsifier.

[0027] Example 9 Evaluation of Demulsifier Performance The demulsification performance of the demulsifier of the present invention (Examples 1-8) was tested by taking crude oil from the oil-water transition zone in a crude oil gathering tank of an oil production plant in Shengli Oilfield. The emulsified oil in the oil-water transition zone had an oil content of 52000 mg / L. The evaluation method was based on SY / T 5281-2000 "Crude Oil Demulsifier Performance Test Method", the experimental temperature was 50°C, and the dosing concentration was 40 and 80 mg / L. The SP-169 crude oil demulsifier from Hai'an Petrochemical Plant in Jiangsu Province was used for comparative experiments, and the test results are shown in Table 1.

[0028] Table 1 Experimental results of crude oil demulsifier From Table 1 we can see that: (1) When the demulsifier of the present invention (Examples 1-8) is used at a concentration of 40 mg / L for 52000 mg / L of emulsified oil in the oil-water transition zone, the dehydration amount of 100 ml of emulsion in 90 minutes reaches more than 85 ml, the water phase after demulsification is clear, the oil content is less than 100 mg / L, and the oil-water interface is clear; while the SP-169 crude oil demulsifier of the comparative example Hai'an Petrochemical Plant in Jiangsu Province has a dehydration amount of 68 ml in 90 minutes, the oil-water interface after demulsification is blurred, the oil content is 280 mg / L, and the demulsification effect is significantly lower than that of the present invention; (2) When the demulsifier of the present invention (Examples 1-8) is used at a concentration of 80 mg / L for 52000 mg / L of emulsified oil in the oil-water transition zone, the dehydration volume of 100 ml of emulsion in 90 minutes reaches 89 ml or more, the water phase after demulsification is clear, the oil content is not higher than 90 mg / L, and the oil-water interface is clear; while the SP-169 crude oil demulsifier of the comparative example Hai'an Petrochemical Plant in Jiangsu Province has a dehydration volume of 79 ml in 90 minutes, a clear oil-water interface after demulsification, and an oil content of 126 mg / L, and the demulsification effect is significantly lower than that of the present invention.

[0029] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for preparing a demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation, characterized in that: The specific steps of the preparation method are as follows: (1) The first reactor and pipeline were purged with nitrogen for 8-10 minutes, (3-acryloxypropyl) tris(trimethylsiloxy) silane, diethyl allyl malonate, deionized water, nonylphenol polyoxyethylene ether, sodium salt of alkylphenol ether sulfosuccinate, and sodium dihydrogen phosphate were added, stirred to form an emulsion, and the pH was adjusted to 7-8 with sodium hydroxide solution; (2) Add 3-[(3-acrylamidopropyl)dimethylammonium] propionate, allyl alcohol polyoxyethylene ether and deionized water into the second reactor and heat to dissolve; (3) Add initiator and sodium bisulfite to the first reactor, raise the temperature to 40-50°C, and keep the temperature to react. When the viscosity starts to rise, quickly pour the mixed solution in the second reactor into the reactor, continue the reaction for 0.5-2h, raise the temperature to 60-70°C, keep the temperature for 20-30min, and adjust the pH to 7-8 with sodium hydroxide solution to obtain a viscous liquid; (4) drying and granulating the solution to obtain a demulsifier; Based on 1 mol part of (3-acryloxypropyl)tris(trimethylsiloxy)silane, the amounts of allyl malonate diethyl ester, 3-[(3-acrylamidopropyl)dimethylammonium]propionate, and allyl alcohol polyoxyethylene ether are 0.2-0.4, 0.5-1, and 0.5-1 mol parts, respectively.

2. The method for preparing a demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation as claimed in claim 1, characterized in that: In step (1), the mass ratio of deionized water, nonylphenol polyoxyethylene ether, alkylphenol ether sodium sulfosuccinate, sodium dihydrogen phosphate and (3-acryloxypropyl) tris(trimethylsiloxy)silane is 3-5:0.2-0.5:0.1-0.2:0.1-0.2:

1.

3. The method for preparing a demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation as claimed in claim 1, characterized in that: In step (2), the mass ratio of deionized water to (3-acryloxypropyl)tris(trimethylsiloxy)silane is 6-8:

1.

4. The method for preparing a demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation as claimed in claim 1, characterized in that: In step (3), the mass ratio of the initiator, sodium bisulfite and (3-acryloxypropyl)tris(trimethylsiloxy)silane is 0.1-0.2:0.05-0.1:

1.

5. The method for preparing a demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation as claimed in claim 1, characterized in that: In step (3), the initiator is one of sodium persulfate, potassium persulfate and ammonium persulfate.

6. A demulsifier for breaking the oil-water transition zone for oil and gas gathering and transportation, characterized in that: The molecular formula of the demulsifier is as follows: Where: a=5000-50000； b=1000-20000； c=2500-50000； d=2500-50000； n is a positive integer from 10 to 20.

7. The demulsifier according to claim 6, characterized in that The viscosity average molecular weight of the demulsifier is 10,000,000-20,000,000.

Images