An anti-emulsifying demulsifier for treating oilfield produced fluid and a preparation method thereof

Abstract

The present invention belongs to the technical field of oilfield chemistry, and particularly relates to an emulsion-proof demulsifier for treating oilfield produced liquid and a preparation method thereof. The preparation method is as follows: Add p-aminopyridine, 37 wt% formaldehyde, formic acid, and distilled water into a reactor, heat and reflux for reaction, cool, and perform vacuum distillation to obtain a viscous liquid; Dissolve the above viscous liquid with isobutanol, add chloroethanol, heat and reflux for reaction, perform vacuum distillation to obtain a viscous reddish-brown solid, and recrystallize to obtain a white-like solid; Dissolve the above white solid with toluene, transfer it to a high-pressure reactor, add a catalyst, introduce propylene oxide, raise the temperature, keep the temperature, lower the temperature, adjust the pH, and perform vacuum distillation to obtain the product emulsion-proof demulsifier. The emulsion-proof demulsifier of the invention has the characteristics of simple synthesis process and good emulsion-proof and demulsification effects.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield chemistry, and particularly relates to an anti-emulsification and demulsification agent for treating oilfield produced fluids and a preparation method thereof. Background Art

[0002] With the continuous exploitation of crude oil, the water content of crude oil gradually increases. This oil-water mixture gradually forms a stable oil-in-water (O / W) emulsion through nozzles and gathering pipelines. Such emulsions are mainly of the oil-in-water (O / W) type, and their specific gravity is increasing, making the treatment more difficult. The water quality is becoming increasingly complex, showing characteristics such as high salinity, high oil emulsification degree, high content of small particle size suspended solids, high polymer content, high bacterial content, and high corrosion rate. Moreover, the density difference between oil and water is small, the phase state is stable, and the oil-water separation is difficult, which restricts the development of oil production technology.

[0003] For such problems, the solution is usually to add a demulsifier to the produced water to achieve oil-water separation. For demulsifying oil-in-water (O / W) emulsions, the types of demulsifiers used mainly include low molecular weight electrolytes, alcohols, surfactants, and high molecular polymers. These demulsifiers have their own characteristics. For example, polyquaternary ammonium salt demulsifiers have the advantages of good water solubility and fast diffusion rate, and polyether demulsifiers have the characteristics of long branched chains, large relative molecular mass, and good demulsification performance.

[0004] However, these agents generally have difficulty meeting the requirements for treating polymer flooding produced fluids, showing that the oil content in the lower layer of water after demulsification is high, increasing the cost and difficulty of the sewage treatment system.

[0005] CN109734835A discloses an acrylate emulsion reverse demulsifier and a preparation method thereof. The acrylate emulsion reverse demulsifier of this invention is prepared by adding anionic monomers, acrylamide, and acrylate monomers, then adding an emulsifier accounting for 1-4% of the monomer mass, and finally adding an appropriate amount of water. Under nitrogen protection, part of the initiator is added dropwise to initiate the pre-polymerization of part of the monomers to obtain a seed emulsion. The remaining monomer mixture and the initiator are gradually added dropwise into the seed emulsion for polymerization reaction. After the addition of the initiator is completed, the reaction is maintained at a certain temperature for 1-3 h to obtain the acrylate emulsion reverse demulsifier. The acrylate emulsion prepared by the method of this invention belongs to an anionic emulsion type reverse demulsifier and has good demulsification and water purification effects on treating high water cut crude oil produced fluids. However, the monomers in this invention are anionic, and anionic surfactants are also used in the ternary composite flooding. There may be a consequence of exacerbating emulsification for the produced fluids of ternary composite flooding.

[0006] CN112915593A discloses an emulsion-type reverse demulsifier for offshore oilfields and its preparation method. The method includes two steps: step one is the compound dissolution of cationic polyacrylamide and alkanolamine resin polyether, and step two is the preparation of the emulsion-type reverse demulsifier. The present invention uses cationic polyacrylamide and diethanolamine resin polyether as raw materials for compounding, and by adding a solubilizer and a stabilizer, an emulsion-type reverse demulsifier for offshore oilfields is prepared. When the reverse demulsifier of the present invention is used to treat the oily sewage generated in high-water-cut oilfields, it has a good treatment effect. However, the present invention has the disadvantages of low oil removal rate and incomplete demulsification effect, and cannot meet the needs of oilfield production for the treatment of produced water with high requirements. Summary of the Invention

[0007] The present invention provides an anti-emulsification and demulsification agent for treating oilfield produced fluids and its preparation method in view of the deficiencies of the current existing technologies. The anti-emulsification and demulsification agent of the present invention has the characteristics of simple synthesis process and good anti-emulsification and demulsification effects.

[0008] One of the purposes of the present invention is to disclose an anti-emulsification and demulsification agent for treating oilfield produced fluids. The molecular formula of the anti-emulsification and demulsification agent is as follows:

[0009]

[0010] In the formula:

[0011] n is a positive integer from 4 to 20.

[0012] Another purpose of the present invention is to provide a preparation method of the above anti-emulsification and demulsification agent. The preparation method includes: 4-aminopyridine reacts with formaldehyde under the condition of formic acid as a reducing agent to carry out the Eschweiler–Clarke reaction to obtain a methylated tertiary amine intermediate; in an isobutanol solvent, the tertiary amine intermediate reacts with chloroethanol under high-temperature conditions to carry out a quaternization reaction to obtain a quaternary ammonium salt; under high-temperature, high-pressure and catalyst conditions, the quaternary ammonium salt reacts with propylene oxide, and a propyl ether segment is embedded in the molecule to obtain the product anti-emulsification and demulsification agent.

[0013] According to a more specific preferred embodiment, the preparation method of the anti-emulsification and demulsification agent specifically includes the following steps:

[0014] (1) Add 4-aminopyridine, 37 wt% formaldehyde, formic acid, and distilled water into a reactor, stir evenly, heat under reflux, cool to below 40 °C, and carry out vacuum distillation to obtain a viscous liquid;

[0015] (2) Dissolve the above viscous liquid with isobutanol, add chloroethanol, heat under reflux, and carry out vacuum distillation to obtain a viscous reddish-brown solid;

[0016] (3) Recrystallize the solid with ethyl acetate to obtain an off-white solid;

[0017] (4) Dissolve the above white solid in toluene, transfer it to a high-pressure reactor, add a catalyst, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce propylene oxide, raise the temperature to 130 - 150 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% concentrated sulfuric acid, and distill off toluene under reduced pressure to obtain the product anti-emulsion demulsifier.

[0018] In the present invention, preferably, based on 1 mole part of 4-aminopyridine, the amounts of formaldehyde, chloroethanol, and propylene oxide are 2 - 6 mole parts, 0.7 - 1.2 mole parts, and 3 - 20 mole parts respectively; more preferably, based on 1 mole part of 4-aminopyridine, the amounts of formaldehyde, chloroethanol, and propylene oxide are 3 - 6 mole parts, 0.8 - 1.1 mole parts, and 5 - 20 mole parts respectively.

[0019] Preferably, in step (1), the weight ratio of formic acid to 4-aminopyridine is 1 - 3:1.

[0020] Preferably, in step (1), the weight ratio of distilled water to 4-aminopyridine is 15 - 20:1.

[0021] Preferably, in step (1), the heating reflux reaction time is 3 - 5 h.

[0022] Preferably, in step (2), the weight ratio of isobutanol to 4-aminopyridine is 30 - 40:1.

[0023] Preferably, in step (2), the heating reflux time is 24 - 48 h.

[0024] Preferably, in step (3), the weight ratio of ethyl acetate to 4-aminopyridine is 5 - 6:1.

[0025] Preferably, in step (4), the weight ratio of toluene to 4-aminopyridine is 5 - 8:1.

[0026] Preferably, in step (4), the catalyst is one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate solids, and the dosage is 0.2 - 1 times the weight of 4-aminopyridine.

[0027] Preferably, in step (4), the heat preservation time is 6 - 12 h.

[0028] The present invention has the following advantages and beneficial effects compared with the prior art:

[0029] (1) The raw materials of the anti-emulsion demulsifier of the present invention are widely sourced and the synthesis process is simple;

[0030] (2) The anti-emulsifying demulsifier of the present invention has good anti-emulsifying effect. When the dosage is 20 mg / L, the anti-emulsifying rate reaches over 97%;

[0031] (3) The anti-emulsifying demulsifier of the present invention has good oil removal effect. When the dosage is 20 mg / L, the oil removal rate reaches over 96%.

[0032] The anti-emulsifying demulsifier of the present invention is a strongly positive surfactant. The hydrophilic group is a quaternary ammonium salt and a pyridine group, and the lipophilic group is a polypropylene ether segment. It can neutralize anionic surfactants, lose the function of reducing the oil-water interfacial tension, increase the oil-water interfacial tension, and reduce the stability of the interfacial film; it can further reduce the oil droplet diffusion layer, ultimately leading to the destruction of the double electric layer; it can enter the oil-water interface, replace the surfactant with strong emulsifying ability, displace the surfactant molecules and other surface active substances, destroy the emulsifying ability of the oil droplets, make the small oil droplets easier to approach and aggregate, so as to achieve oil-water separation; it can sweep a large number of negatively charged oil droplets, increase the collision chance between the cations of the present invention and the anions in the crude oil, neutralize the electric charge on the surface of the oil droplets, and form an unstable film.

[0033] The reaction equation of the anti-emulsifying demulsifier of the present invention is:

[0034]

[0035] Detailed implementation manners

[0036] The present invention will be further described in detail below with reference to specific examples and data. It should be understood that these examples are only for illustrating the present invention and do not limit the scope of the present invention in any way.

[0037] Example 1

[0038] (1) Add 0.2 mol of p-aminopyridine, 0.4 mol of 37 wt% formaldehyde, 27.4 g of formic acid, and 282 g of distilled water into a reactor, stir evenly, heat under reflux for 3 h, cool to below 40 °C, and distill under reduced pressure to obtain a viscous liquid;

[0039] (2) Dissolve the above viscous liquid with 564 g of isobutanol, add 0.14 mol of chloroethanol, heat under reflux for 24 h, and distill under reduced pressure to obtain a viscous reddish-brown solid;

[0040] (3) Recrystallize the solid with 94 g of ethyl acetate to obtain a white solid;

[0041] (4) Dissolve the above-mentioned white solid in 94 g of toluene, transfer it to an autoclave, add 9.43 g of solid sodium carbonate, purge with nitrogen for 20 min to remove the oxygen in the autoclave, introduce 1 mol of propylene oxide, heat up to 130 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature for 6 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F1.

[0042] Example 2

[0043] (1) Add 0.2 mol of 4-aminopyridine, 0.51 mol of 37 wt% formaldehyde, 18.8 g of formic acid, and 314 g of distilled water to a reactor, stir evenly, heat under reflux for 3.5 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid;

[0044] (2) Dissolve the above-mentioned viscous liquid in 588 g of isobutanol, add 0.16 mol of chloroethanol, heat under reflux for 30 h, and distill under reduced pressure to obtain a viscous reddish-brown solid;

[0045] (3) Recrystallize the solid with 97.3 g of ethyl acetate to obtain an off-white solid;

[0046] (4) Dissolve the above-mentioned white solid in 99.4 g of toluene, transfer it to an autoclave, add 18.8 g of solid sodium carbonate, purge with nitrogen for 20 min to remove the oxygen in the autoclave, introduce 1.2 mol of propylene oxide, heat up to 150 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature for 7 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F2.

[0047] Example 3

[0048] (1) Add 0.2 mol of 4-aminopyridine, 0.6 mol of 37 wt% formaldehyde, 19.5 g of formic acid, and 376 g of distilled water to a reactor, stir evenly, heat under reflux for 4 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid;

[0049] (2) Dissolve the above-mentioned viscous liquid in 623 g of isobutanol, add 0.24 mol of chloroethanol, heat under reflux for 36 h, and distill under reduced pressure to obtain a viscous reddish-brown solid;

[0050] (3) Recrystallize the solid with 99.9 g of ethyl acetate to obtain an off-white solid;

[0051] (4) Dissolve the above white solid in 107.2 g of toluene, transfer it to a high-pressure reactor, add 12.75 g of potassium carbonate solid, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce 1.5 mol of propylene oxide, heat up to 135 °C, control the pressure at 0.3 - 0.4 MPa, keep warm for 8 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% concentrated sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F3.

[0052] Example 4

[0053] (1) Add 0.2 mol of 4-aminopyridine, 0.74 mol of 37 wt% formaldehyde, 35.2 g of formic acid, and 353 g of distilled water to a reactor, stir evenly, heat under reflux for 4 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid;

[0054] (2) Dissolve the above viscous liquid in 674 g of isobutanol, add 0.15 mol of chloroethanol, heat under reflux for 36 h, and distill under reduced pressure to obtain a viscous reddish-brown solid;

[0055] (3) Recrystallize the solid with 100.8 g of ethyl acetate to obtain an off-white solid;

[0056] (4) Dissolve the above white solid in 110 g of toluene, transfer it to a high-pressure reactor, add 10.02 g of sodium carbonate solid, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce 1.8 mol of propylene oxide, heat up to 140 °C, control the pressure at 0.3 - 0.4 MPa, keep warm for 8 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% concentrated sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F4.

[0057] Example 5

[0058] (1) Add 0.2 mol of 4-aminopyridine, 0.85 mol of 37 wt% formaldehyde, 49.4 g of formic acid, and 294 g of distilled water to a reactor, stir evenly, heat under reflux for 5 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid;

[0059] (2) Dissolve the above viscous liquid in 752 g of isobutanol, add 0.23 mol of chloroethanol, heat under reflux for 36 h, and distill under reduced pressure to obtain a viscous reddish-brown solid;

[0060] (3) Recrystallize the solid with 105.6 g of ethyl acetate to obtain an off-white solid;

[0061] (4) Dissolve the above white solid in 123.4 g of toluene, transfer it to a high-pressure reactor, add 3.76 g of solid sodium hydroxide, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce 2.2 mol of propylene oxide, heat up to 135 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature for 12 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% concentrated sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F5.

[0062] Example 6

[0063] (1) Add 0.2 mol of 4-aminopyridine, 0.92 mol of 37 wt% formaldehyde, 56.4 g of formic acid, and 303 g of distilled water to a reactor, stir evenly, heat under reflux for 4.5 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid;

[0064] (2) Dissolve the above viscous liquid in 707 g of isobutanol, add 0.17 mol of chloroethanol, heat under reflux for 40 h, and distill under reduced pressure to obtain a viscous reddish-brown solid;

[0065] (3) Recrystallize the solid with 109.4 g of ethyl acetate to obtain an off-white solid;

[0066] (4) Dissolve the above white solid in 144.7 g of toluene, transfer it to a high-pressure reactor, add 5.58 g of solid sodium hydroxide, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce 2.7 mol of propylene oxide, heat up to 145 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature for 11 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% concentrated sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F6.

[0067] Example 7

[0068] (1) Add 0.2 mol of 4-aminopyridine, 1 mol of 37 wt% formaldehyde, 51.2 g of formic acid, and 350 g of distilled water to a reactor, stir evenly, heat under reflux for 4 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid;

[0069] (2) Dissolve the above viscous liquid in 716 g of isobutanol, add 0.18 mol of chloroethanol, heat under reflux for 48 h, and distill under reduced pressure to obtain a viscous reddish-brown solid;

[0070] (3) Recrystallize the solid with 108.2 g of ethyl acetate to obtain an off-white solid;

[0071] (4) Dissolve the above white solid in 130.8 g of toluene, transfer it to a high-pressure reactor, add 6.66 g of solid sodium hydroxide, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce 3.1 mol of propylene oxide, heat up to 150 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature for 10 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% concentrated sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F7.

[0072] Example 8

[0073] (1) Add 0.2 mol of 4-aminopyridine, 1.05 mol of 37 wt% formaldehyde, 43.3 g of formic acid, and 327 g of distilled water to a reactor, stir evenly, heat under reflux for 4 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid.

[0074] (2) Dissolve the above viscous liquid in 728 g of isobutanol, add 0.2 mol of chloroethanol, heat under reflux for 48 h, and distill under reduced pressure to obtain a viscous reddish-brown solid.

[0075] (3) Recrystallize the solid with 107 g of ethyl acetate to obtain an off-white solid.

[0076] (4) Dissolve the above white solid in 135.3 g of toluene, transfer it to a high-pressure reactor, add 7.17 g of solid potassium hydroxide, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce 3.5 mol of propylene oxide, heat up to 130 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature for 11 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% concentrated sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F8.

[0077] Example 9

[0078] (1) Add 0.2 mol of 4-aminopyridine, 1.11 mol of 37 wt% formaldehyde, 45.6 g of formic acid, and 344 g of distilled water to a reactor, stir evenly, heat under reflux for 4 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid.

[0079] (2) Dissolve the above viscous liquid in 741 g of isobutanol, add 0.21 mol of chloroethanol, heat under reflux for 48 h, and distill under reduced pressure to obtain a viscous reddish-brown solid.

[0080] (3) Recrystallize the solid with 112.8 g of ethyl acetate to obtain an off-white solid.

[0081] (4) Dissolve the above-mentioned white solid in 149.4 g of toluene, transfer it to a high-pressure reactor, add 8.03 g of potassium hydroxide solid, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce 3.8 mol of propylene oxide, heat up to 135 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature for 12 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F9.

[0082] Example 10

[0083] (1) Add 0.2 mol of 4-aminopyridine, 1.2 mol of 37 wt% formaldehyde, 37.9 g of formic acid, and 333 g of distilled water to a reactor, stir evenly, heat under reflux for 5 h, cool down to below 40 °C, and distill under reduced pressure to obtain a viscous liquid;

[0084] (2) Dissolve the above-mentioned viscous liquid in 750 g of isobutanol, add 0.22 mol of chloroethanol, heat under reflux for 48 h, and distill under reduced pressure to obtain a viscous reddish-brown solid;

[0085] (3) Recrystallize the solid with 110.3 g of ethyl acetate to obtain a near-white solid;

[0086] (4) Dissolve the above-mentioned white solid in 150.4 g of toluene, transfer it to a high-pressure reactor, add 9.59 g of potassium hydroxide solid, purge with nitrogen for 20 min to remove the oxygen in the reactor, introduce 4 mol of propylene oxide, heat up to 145 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature for 12 h, cool down to below 40 °C, adjust the pH to about 7 with 50 wt% sulfuric acid, and distill off toluene under reduced pressure to obtain the demulsifier product F 10 。

[0087] Example 11 Test on the anti-emulsification rate of the anti-emulsification and demulsification agent

[0088] Add 100 g of sodium chloride, 1 g of sodium carbonate, 2 g of PAM, and 0.5 g of petroleum sulfonate to 10 L of deionized water, stir until completely dissolved to obtain a ternary composite flooding simulated produced water with concentrations of sodium chloride 10000 mg / L, sodium carbonate 100 mg / L, PAM 200 mg / L, and petroleum sulfonate 50 mg / L respectively.

[0089] Add 500 mL of the simulated water to a series of beakers, add 10 ml of 10 wt% crude oil petroleum ether solution and anti-emulsification and demulsification agents with different concentrations, emulsify with a crude oil emulsifier at a speed of 15000 rpm for 5 min, let it stand for 6 h, test the oil content in the aqueous phase, and at the same time make a blank oil content C0.

[0090] Test the oil content C in the lower aqueous phase and calculate the anti-emulsification rate.

[0091] Demulsification prevention rate = (C0 - C) / C0 × 100%

[0092] Blank oil content: 280 mg / L.

[0093] A comparative experiment was conducted using demulsifier BP-169, and the test results are shown in Table 1.

[0094] Table 1 Test results of demulsification prevention rate of demulsification prevention and demulsifying agent

[0095]

[0096] It can be seen from Table 1 that:

[0097] (1) The demulsification prevention agents F1, F2, F3, F4, F5, F6, F7, F8, F9, F of the present invention 10 When the concentration is 10 mg / L, the demulsification prevention rate is greater than 96%, reaching a maximum of 97.3%; while the demulsification prevention rate of the comparative sample BP-169 is 96.5%, which is significantly lower than that of the present invention;

[0098] (2) The demulsification prevention agents F1, F2, F3, F4, F5, F6, F7, F8, F9, F of the present invention 10 When the concentration is 20 mg / L, the demulsification prevention rate is greater than 97%, reaching a maximum of 98.2%; while the demulsification prevention rate of the comparative sample BP-169 is 90.8%, which is significantly lower than that of the present invention.

[0099] The demulsification prevention and demulsifying agent of the present invention has good demulsification prevention ability.

[0100] Performance test of demulsifying agent in Example 12

[0101] Experimental object: Produced water containing oil from a ternary composite flooding joint station in Shengli Oilfield, with an oil content of 208 mg / L. Demulsification experiment method: Refer to SY / T5281-2000 "Detection Method for Performance of Crude Oil Demulsifier", the addition amounts of demulsifier are 10 and 20 mg / L respectively, and the treatment time is 2 min.

[0102] Table 2 Test results of oil removal rate of demulsification prevention and demulsifying agent

[0103]

[0104]

[0105] It can be seen from Table 2 that:

[0106] (1) The demulsification prevention agents F1, F2, F3, F4, F5, F6, F7, F8, F9, F of the present invention 10When the concentration is 10 mg / L, the oil removal rate is greater than 94%, reaching a maximum of 95.3%; while the oil removal rate of the comparative sample BP-169 is 80.0%, which is significantly lower than that of the present invention.

[0107] (2) The anti-emulsion demulsifiers F1, F2, F3, F4, F5, F6, F7, F8, F9, F 10 When the concentration is 20 mg / L, the oil removal rate is greater than 96%, reaching a maximum of 97.1%; while the oil removal rate of the comparative sample BP-169 is 86.6%, which is significantly lower than that of the present invention.

[0108] The anti-emulsion demulsifiers of the present invention have good oil removal performance.

[0109] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A preparation method of an anti-emulsification and demulsification agent for treating oilfield produced fluid, characterized in that, The described preparation method specifically includes the following steps: (1) Add 4-aminopyridine, 37 wt% formaldehyde, formic acid, and distilled water into a reactor, stir evenly, heat under reflux, cool to below 40 °C, and perform vacuum distillation to obtain a viscous liquid; (2) Dissolve the above viscous liquid with isobutanol, add chloroethanol, heat under reflux, and perform vacuum distillation to obtain a viscous reddish-brown solid; (3) Recrystallize the solid with ethyl acetate to obtain an off-white solid; (4) Dissolve the above off-white solid with toluene, transfer it to a high-pressure reactor, add a catalyst, purge with nitrogen for 20 min to remove oxygen in the reactor, introduce propylene oxide, heat up to 130 - 150 °C, control the pressure at 0.3 - 0.4 MPa, keep the temperature, cool to below 40 °C, adjust the pH to 7 with 50 wt% sulfuric acid, and perform vacuum distillation to remove toluene to obtain the product anti-emulsion demulsifier; Based on 1 mole part of 4-aminopyridine, the dosages of formaldehyde, chloroethanol, and propylene oxide are 2 - 6 mole parts, 0.7 - 1.2 mole parts, and 3 - 20 mole parts respectively.

2. The preparation method of an anti-emulsification and demulsification agent for treating oilfield produced liquid according to claim 1, wherein, Based on 1 mole part of 4-aminopyridine, the dosages of formaldehyde, chloroethanol, and propylene oxide are 3 - 6 mole parts, 0.8 - 1.1 mole parts, and 5 - 20 mole parts respectively.

3. The preparation method of an anti-emulsification and demulsification agent for treating oilfield produced fluids according to claim 1, characterized in that, In step (1), the weight ratio of formic acid to 4-aminopyridine is 1 - 3:

1.

4. The preparation method of an anti-emulsification and demulsification agent for treating oilfield produced fluid according to claim 1, characterized in that, In step (1), the heating reflux reaction time is 3 - 5 h.

5. The preparation method of an anti-emulsification and demulsification agent for treating oilfield produced fluid according to claim 1, characterized in that, In step (2), the heating reflux time is 24 - 48 h.

6. The preparation method of an anti-emulsification and demulsification agent for treating oilfield produced fluid according to claim 1, wherein, In step (4), the catalyst is one of sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate solids, and the dosage is 0.2 - 1 times the weight of 4-aminopyridine.

7. The preparation method of an anti-emulsification and demulsification agent for treating oilfield produced fluid according to claim 1, characterized in that, In step (4), the heat preservation time is 6 - 12 h.

8. The preparation method of an anti-emulsification and demulsification agent for treating oilfield produced fluid according to claim 1, wherein, In step (4), the weight ratio of toluene to 4-aminopyridine is 5 - 8:

1.

9. An anti-emulsification and demulsification agent for treating oilfield produced fluid, characterized in that, The molecular formula of the described anti-emulsion demulsifier is as follows: In the formula: n is a positive integer from 4 to 20.

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