A viscosity reducer for thick oil, and a preparation method and application thereof

Abstract

The application belongs to the technical field of tertiary oil recovery, and relates to a heavy oil viscosity reducer and a preparation method and application thereof.The preparation method is as follows: p-nonyl phenol, 1-(4-fluorophenyl)piperazine, 40wt% formaldehyde and water are added into a reactor, stirring is carried out, temperature is increased to reflux, and temperature is kept;temperature is reduced to below 40 DEG C, extraction is carried out, the obtained product is placed in a high-pressure reactor, sodium hydroxide solid is added, nitrogen is introduced, vacuum is drawn, temperature is increased, vacuum drawing is stopped, ethylene oxide is slowly introduced, temperature is increased, and temperature is kept;viscous liquid is obtained through reduced pressure distillation, the obtained product is placed in a high-pressure reactor, pH is adjusted to 3-4, aminosulfonic acid powder is added, stirring and heating are carried out, temperature is kept, and the obtained product is cooled to below 40 DEG C;ethanolamine is added, pH is adjusted to 7-8, and the heavy oil viscosity reducer is obtained.The viscosity reducer has the advantages of low surface tension, low interfacial tension, low critical micelle concentration and good viscosity reduction effect.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of tertiary oil recovery, and relates to a heavy oil viscosity reducer as well as a preparation method and application thereof. BACKGROUND

[0002] Global heavy oil accounts for more than 70% of the total amount of remaining oil resources, and China also has rich heavy oil reserves. With the continuous depletion of light crude oil resources, the importance of heavy oil exploitation is increasingly prominent. Heavy oil has high density and high viscosity due to high content of resin and asphaltene, which brings great difficulty to exploitation and transportation. Its poor flowability makes it difficult to be normally exploited, increases energy consumption and equipment wear and tear in the exploitation process, and increases the exploitation cost.

[0003] In order to improve the recovery rate of heavy oil, it is necessary to effectively reduce the viscosity of heavy oil and improve its flowability, so that heavy oil can be more smoothly produced from the formation.

[0004] At present, the commonly used viscosity reduction methods in the process of heavy oil exploitation at home and abroad include heating viscosity reduction, hydrothermal cracking viscosity reduction, light oil dilution, microbial viscosity reduction and chemical viscosity reduction. Chemical viscosity reduction refers to adding viscosity reducers to crude oil to reduce the viscosity of crude oil.

[0005] The main mechanisms of viscosity reduction of viscosity reducers include emulsification viscosity reduction and wetting resistance reduction: under the action of viscosity reducers, the internal friction between oil and oil is converted into the friction between water and water, thereby greatly reducing the viscosity of heavy oil; the viscosity reducer can reverse the interfacial lipophilicity to hydrophilicity, forming a continuous water film and reducing the flow resistance of heavy oil.

[0006] CN112011325A discloses an oil-soluble heavy oil viscosity reducer, which comprises fatty acid methyl ester, and the number of carbon atoms in the fatty acid part of the fatty acid methyl ester ranges from 12 to 24. The synthesis conditions of the fatty acid methyl ester of the application are mild, and the raw materials are widely available, have large yield, low price and are easy to obtain, so the cost is low. For example, the purity of methanol required in the generation process is different. The fatty acid methyl ester prepared by the application has good flowability and viscosity reduction effect, the raw materials are easy to obtain, the synthesis operation process is simple, and complex or harsh synthesis conditions are not required. The addition amount of the heavy oil viscosity reducer of the application is not more than 40% of the total mass of the heavy oil, the viscosity reducer can be used in small amount, and the viscosity of the heavy oil can be reduced by more than 90%. Therefore, the fatty acid methyl ester of the application is suitable for large-scale oil field exploitation and gathering and transportation. However, for super heavy oil, a viscosity reduction of 90% cannot meet the actual needs, and the exploitation and transportation are still difficult.

[0007] CN102604618A discloses a kind of heavy oil cold production formation crude oil viscosity reducer, applied to oilfield heavy oil cold production formation crude oil processing, improve formation crude oil flowability.The weight percentage of each component: N, N-octanoyl bis sodium taurate: 10.2~11.5%; Sodium lauryl methyl taurate: 18.6~19.0%; Sodium secondary alkyl sulfate: 15.3~15.8%; Emulsifier OPE-12: 3.5~4.5%; Sodium oleate: 0.1~0.15%; Sodium hydroxide: 0.1~0.15%; the rest is water, the sum of the weight percentage of each component is 100%.The effect is: can make heavy oil in oil layer viscosity reduction, improve the flowability of heavy oil in oil layer, solve the problem of heavy oil flow into wellbore difficulty in underground oil layer.But the invention needs to be compounded alkaline substance to have better emulsification viscosity reduction effect to heavy oil when using, and the addition of alkaline substance will lead to clay swelling on one hand, potential harm to the oil production process, on the other hand, demulsification difficulty in later period, additional workload to crude oil processing. SUMMARY

[0008] The present application provides a kind of heavy oil viscosity reducer and its preparation method and application for the above prior art existing deficiencies.The viscosity reducer of the present application has the advantages of low surface tension, low interfacial tension, low critical micelle concentration, good viscosity reduction effect.

[0009] In order to achieve the above purpose:

[0010] The first aspect, the present application discloses a kind of heavy oil viscosity reducer preparation method, the specific steps of the preparation method are as follows:

[0011] (1) in the reactor, add p-nonyl phenol, 1-(4-fluorophenyl) piperazine, 40wt% formaldehyde, water, stir and heat to reflux, keep warm for 6-8h;

[0012] (2) cool down to below 40℃, extract twice with toluene, combine toluene, place in high pressure reactor, add sodium hydroxide solid, introduce nitrogen, vacuum, heat to 80-85℃, stop vacuum, slowly introduce ethylene oxide, heat to 140-170℃, keep warm until the pressure no longer drops to stop reaction;

[0013] (3) reduce pressure distillation to obtain viscous liquid, place in high pressure reactor, adjust pH to 3-4 with sulfuric acid, add aminosulfonic acid powder, stir and heat, keep warm at 130-140℃ for 2-3h, cool down to below 40℃, add 10wt% ethanolamine, adjust pH to 7-8 with sodium hydroxide solution, to obtain product heavy oil viscosity reducer.

[0014] In the present application, preferably, based on 1 mole of nonyl phenol, the amount of 1-(4-fluorophenyl) piperazine, 40wt% formaldehyde, ethylene oxide, sulfamic acid is 1.6-2.4 moles, 3-5 moles, 2-20 moles, 0.8-1.2 moles, respectively.

[0015] More preferably, based on 1 mole of nonyl phenol, the amount of 1-(4-fluorophenyl) piperazine, 40wt% formaldehyde, ethylene oxide, sulfamic acid is 1.8-2.2 moles, 4-5 moles, 5-20 moles, 0.9-1.1 moles, respectively.

[0016] In the present application, preferably, the weight ratio of water to nonyl phenol in step (1) is 6-8:1.

[0017] In the present application, preferably, the weight ratio of toluene to nonyl phenol in step (2) is 4-6:1.

[0018] In the present application, preferably, the weight ratio of sodium hydroxide to nonyl phenol in step (2) is 0.2-0.3:1.

[0019] In the present application, preferably, the weight ratio of 10wt% ethanolamine to nonyl phenol in step (3) is 3-5:1.

[0020] The reaction equation of the heavy oil viscosity reducer of the present application is as follows:

[0021]

[0022] In another aspect, the present application discloses a heavy oil viscosity reducer, and the molecular structure of the heavy oil viscosity reducer is as follows:

[0023] .

[0024] In a third aspect, the present application discloses the application of the above heavy oil viscosity reducer in improving the recovery rate of heavy oil.

[0025] The thickened oil viscosity reducer belongs to a non-ion and anion composite viscosity reducer. The lipophilic group is fluorophenyl and nonyl, so that the molecule can quickly penetrate into the oil phase from the water phase through the oil-water interface, easily produce intermolecular interaction with aromatic ring compounds, long-chain aliphatic hydrocarbons and the like in the crude oil, form a stable O / W emulsion under low power, and greatly reduce the viscosity of the crude oil. The fluorophenyl belongs to a special lipophilic group, and has better interfacial activity. The hydrophilic group is an epoxy ether and an ammonium sulfonate, and belongs to a non-ion and anion composite viscosity reducer, so that a continuous water film can be formed in the outer phase of the emulsion, the flow resistance can be reduced, and the viscosity of the crude oil can be greatly reduced.

[0026] Compared with the prior art, the thickened oil viscosity reducer has the following advantages and beneficial effects:

[0027] (1) The thickened oil viscosity reducer has the characteristics of low surface and interfacial tension, and the surface tension is as low as 25.8 mN / m and the interfacial tension is as low as 0.65*10 -3 mN / m at a concentration of 500 mg / L.

[0028] (2) The thickened oil viscosity reducer has the characteristics of low critical micelle concentration, and the lowest critical micelle concentration is 70 mg / L.

[0029] (3) The thickened oil viscosity reducer has the characteristics of good viscosity reduction effect, and the viscosity reduction rate is more than 99% for different thickened oils. DETAILED DESCRIPTION

[0030] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values and should be understood to include values approximately near these ranges and values within these ranges. For ranges, the endpoints are included within the ranges, and the ranges are inclusive of the single points and the individual points are included within the ranges. The single points are included within the ranges.

[0031] The application will be further described below with reference to specific examples:

[0032] Example 1

[0033] (1) 0.1 mol of p-nonyl phenol, 0.24 mol of 1-(4-fluorophenyl) piperazine, 0.35 mol of 40wt% formaldehyde and 176g of water were added to a reactor, and stirred to reflux, and reacted for 6h under temperature preservation;

[0034] (2) The temperature was lowered to below 40℃, and 132g of toluene was extracted twice, and the toluene was combined and placed in a high-pressure reactor, 4.8g of sodium hydroxide solid was added, nitrogen was introduced, vacuum was extracted, the temperature was raised to 80℃, vacuum extraction was stopped, 0.4mol of ethylene oxide was slowly introduced, the temperature was raised to 140℃, and the reaction was stopped until the pressure no longer decreased.

[0035] (3) The viscous liquid was obtained by vacuum distillation and placed in a high-pressure reactor. The pH was adjusted to 3-4 with sulfuric acid. 0.12 mol of aminosulfonic acid powder was added and heated with stirring at 130 °C for 2 h. The mixture was cooled to below 40 °C and 70 g of 10 wt% ethanolamine was added. The pH was adjusted to 7-8 with sodium hydroxide solution to obtain the product heavy oil viscosity reducer.

[0036] Example 2

[0037] (1) Add 0.1 mol of p-nonylphenol, 0.18 mol of 1-(4-fluorophenyl)piperazine, 0.4 mol of 40 wt% formaldehyde, and 148 g of water into the reactor, stir, heat, reflux, and keep the reaction for 6 hours;

[0038] (2) Cool down to below 40°C, extract twice with 97g toluene, combine the toluene, place in a high-pressure reactor, add 5.2g sodium hydroxide solid, introduce nitrogen, evacuate, raise the temperature to 82°C, stop evacuating, slowly introduce 0.5mol ethylene oxide, raise the temperature to 140°C, keep the temperature and react until the pressure no longer drops and the reaction is stopped;

[0039] (3) The viscous liquid was obtained by vacuum distillation and placed in a high-pressure reactor. The pH was adjusted to 3-4 with sulfuric acid. 0.085 mol of aminosulfonic acid powder was added and heated with stirring at 132 °C for 2 h. The mixture was cooled to below 40 °C and 75 g of 10 wt% ethanolamine was added. The pH was adjusted to 7-8 with sodium hydroxide solution to obtain the product heavy oil viscosity reducer.

[0040] Example 3

[0041] (1) Add 0.1 mol of p-nonylphenol, 0.18 mol of 1-(4-fluorophenyl)piperazine, 0.4 mol of 40 wt% formaldehyde, and 148 g of water into the reactor, stir, heat, reflux, and keep the reaction warm for 7 hours;

[0042] (2) Cool down to below 40°C, extract twice with 97g toluene, combine the toluene, place in a high-pressure reactor, add 5.2g sodium hydroxide solid, introduce nitrogen, evacuate, raise the temperature to 83°C, stop evacuating, slowly introduce 0.5mol ethylene oxide, raise the temperature to 150°C, keep the temperature and react until the pressure no longer drops and the reaction is stopped;

[0043] (3) The viscous liquid was obtained by vacuum distillation and placed in a high-pressure reactor. The pH was adjusted to 3-4 with sulfuric acid. 0.085 mol of aminosulfonic acid powder was added and heated with stirring at 135 °C for 2.5 h. The mixture was cooled to below 40 °C and 75 g of 10 wt% ethanolamine was added. The pH was adjusted to 7-8 with sodium hydroxide solution to obtain the product heavy oil viscosity reducer.

[0044] Example 4

[0045] (1) In a reactor, add 0.1 mol of p-nonylphenol, 0.22 mol of 1-(4-fluorophenyl)piperazine, 0.5 mol of 40 wt% formaldehyde, 150 g of water, stir to heat to reflux, and keep the temperature constant for 7 h of reaction;

[0046] (2) Cool to below 40°C, extract twice with 108 g of toluene, combine the toluene, place in a high-pressure reactor, add 5.6 g of sodium hydroxide solid, introduce nitrogen, vacuumize, heat to 85°C, stop vacuumizing, slowly introduce 0.8 mol of ethylene oxide, heat to 150°C, keep the temperature constant until the pressure stops dropping to stop the reaction;

[0047] (3) Distill under reduced pressure to obtain a viscous liquid, place in a high-pressure reactor, adjust the pH to 3-4 with sulfuric acid, add 0.105 mol of aminosulfonic acid powder, stir and heat, keep the temperature constant at 135°C for 2.5 h of reaction, cool to below 40°C, add 80 g of 10 wt% ethanolamine, adjust the pH to 7-8 with sodium hydroxide solution to obtain the product thick oil viscosity reducer.

[0048] Example 5

[0049] (1) In a reactor, add 0.1 mol of p-nonylphenol, 0.19 mol of 1-(4-fluorophenyl)piperazine, 0.43 mol of 40 wt% formaldehyde, 166 g of water, stir to heat to reflux, and keep the temperature constant for 6 h of reaction;

[0050] (2) Cool to below 40°C, extract twice with 128 g of toluene, combine the toluene, place in a high-pressure reactor, add 6 g of sodium hydroxide solid, introduce nitrogen, vacuumize, heat to 84°C, stop vacuumizing, slowly introduce 1.2 mol of ethylene oxide, heat to 158°C, keep the temperature constant until the pressure stops dropping to stop the reaction;

[0051] (3) Distill under reduced pressure to obtain a viscous liquid, place in a high-pressure reactor, adjust the pH to 3-4 with sulfuric acid, add 0.09 mol of aminosulfonic acid powder, stir and heat, keep the temperature constant at 138°C for 3 h of reaction, cool to below 40°C, add 90 g of 10 wt% ethanolamine, adjust the pH to 7-8 with sodium hydroxide solution to obtain the product thick oil viscosity reducer.

[0052] Example 6

[0053] (1) In a reactor, add 0.1 mol of p-nonylphenol, 0.21 mol of 1-(4-fluorophenyl)piperazine, 0.45 mol of 40 wt% formaldehyde, 152 g of water, stir to heat to reflux, and keep the temperature constant for 8 h of reaction;

[0054] (2) cooling to below 40℃, extracting twice with 118g of toluene, combining the toluene, placing in a high-pressure reactor, adding 6.3g of sodium hydroxide solid, passing in nitrogen, vacuumizing, warming to 82℃, stopping vacuumizing, slowly passing in 1.6mol of ethylene oxide, warming to 165℃, stopping the reaction when the pressure no longer drops;

[0055] (3) distilling under reduced pressure to obtain a viscous liquid, placing in a high-pressure reactor, adjusting the pH to 3-4 with sulfuric acid, adding 0.11mol of sulfamic acid powder, stirring and heating, reacting at 140℃ for 2.8h, cooling to below 40℃, adding 100g of 10wt% ethanolamine, adjusting the pH to 7-8 with sodium hydroxide solution, to obtain the product viscous oil viscosity reducer.

[0056] Example 7

[0057] (1) adding 0.1mol of p-nonylphenol, 0.2mol of 1-(4-fluorophenyl)piperazine, 0.4mol of 40wt% formaldehyde, 162g of water in a reactor, stirring and warming to reflux, reacting at 8h;

[0058] (2) cooling to below 40℃, extracting twice with 110g of toluene, combining the toluene, placing in a high-pressure reactor, adding 6.6g of sodium hydroxide solid, passing in nitrogen, vacuumizing, warming to 80℃, stopping vacuumizing, slowly passing in 2mol of ethylene oxide, warming to 170℃, reacting until the pressure no longer drops to stop the reaction;

[0059] (3) distilling under reduced pressure to obtain a viscous liquid, placing in a high-pressure reactor, adjusting the pH to 3-4 with sulfuric acid, adding 0.1mol of sulfamic acid powder, stirring and heating, reacting at 140℃ for 3h, cooling to below 40℃, adding 110g of 10wt% ethanolamine, adjusting the pH to 7-8 with sodium hydroxide solution, to obtain the product viscous oil viscosity reducer.

[0060] Example 8 Test of surface tension and interfacial tension

[0061] The viscous oil viscosity reducers (Examples 1-7) of the present application were configured into a 500mg / L aqueous solution, the surface tension and interfacial tension were determined according to the method in SY / T 5370-2018 “Method for Determining Surface and Interfacial Tension”, and the oil phase used for the interfacial tension was n-hexadecane, and the results are shown in Table 1.

[0062] A comparison test was conducted using SHF viscosity reducer from Shengli Oilfield Shengli Chemical Co., Ltd.

[0063] Example 9 Test of critical micelle concentration

[0064] The critical micelle concentration was determined by the method in GB / T 11276-2007 "Determination of Critical Micelle Concentration of Viscosity Reducer", and the results are shown in Table 1.

[0065] The SHF viscosity reducer of Shengli Chemical Co., Ltd. of Shengli Oilfield was used for comparison test.

[0066] Table 1 Test results of surface tension, interfacial tension and critical micelle concentration

[0067]

[0068] As can be seen from Table 1:

[0069] (1) The heavy oil viscosity reducer (Examples 1-7) has the characteristics of low surface and interfacial tension, and the surface tension reaches 26 mN / m or below and the interfacial tension reaches 1 x 10 -3 mN / m or below at a concentration of 500 mg / L, while the surface tension of the SHF viscosity reducer of Shengli Chemical Co., Ltd. of Shengli Oilfield is 30.4 mN / m, and the interfacial tension reaches 310 x 10 -3 mN / m, which is significantly higher than that of the present application;

[0070] (2) The heavy oil viscosity reducer (Examples 1-7) has the characteristics of low critical micelle concentration, reaching 100 mg / L or below, and the lowest being 70 mg / L; while the critical micelle concentration of the SHF viscosity reducer of Shengli Chemical Co., Ltd. of Shengli Oilfield is 580 mg / L, which is significantly higher than that of the present application.

[0071] Example 10 Evaluation of viscosity reduction rate

[0072] The heavy oil viscosity reducer (Examples 1-7) was prepared into a sample with a concentration of 2000 mg / L with tap water, and the viscosity reduction rate was tested by the method in Q / SH1020 1519-2016 "General Technical Conditions for Heavy Oil Viscosity Reducers", and the crude oil used for testing was the oil samples of Block A and Block B of Shengli Oilfield, and the initial viscosity of the crude oil at 50℃ was 7600 mPa·s and 25600 mPa·s, respectively. The results are shown in Table 2.

[0073] The SHF viscosity reducer of Shengli Chemical Co., Ltd. of Shengli Oilfield was used for comparison test.

[0074] Table 2 Viscosity reduction results of viscosity reducers

[0075]

[0076] As can be seen from Table 2, the heavy oil viscosity reducer (Examples 1-7) has the characteristics of good viscosity reduction effect:

[0077] (1) for block A, the initial viscosity of the crude oil is 7600 mPa·s at 50 DEG C, the viscosity reduction rate is more than 99%, and the highest is 99.14%, the viscosity reduction rate of the SHF viscosity reducer of Shengli Oilfield Shengli Chemical Co., Ltd. is 93.16%, which is obviously lower than that of the present application;

[0078] (2) for block B, the initial viscosity of the crude oil is 25600 mPa·s at 50 DEG C, the viscosity reduction rate is more than 99.6%, and the highest is 99.74%, the SHF viscosity reducer of Shengli Oilfield Shengli Chemical Co., Ltd. is not emulsified.

[0079] The preferred embodiments of the present application are described in detail above, but the present application is not limited to the specific details in the above embodiments, and various simple modifications can be made to the technical solutions of the present application within the technical concept of the present application, and these simple modifications all belong to the protection scope of the present application.

[0080] In addition, it should be noted that each specific technical feature described in the above specific embodiments can be combined in any appropriate manner without contradiction, and in order to avoid unnecessary repetition, the present application will not further describe various possible combinations.

[0081] In addition, various different embodiments of the present application can also be combined in any manner, as long as it does not deviate from the idea of the present application, and it should also be considered as disclosed by the present application.

Claims

1. A method for preparing a thick oil viscosity reducer, characterized in that: The specific steps of the preparation method are as follows: (1) Add p-nonylphenol, 1-(4-fluorophenyl)piperazine, 40 wt% formaldehyde, and water into the reactor, stir, heat, reflux, and keep warm for 6-8 hours; (2) Cool down to below 40°C, extract twice with toluene, combine the toluene, place in a high-pressure reactor, add solid sodium hydroxide, introduce nitrogen, evacuate, raise the temperature to 80-85°C, stop evacuating, slowly introduce ethylene oxide, raise the temperature to 140-170°C, keep the temperature and react until the pressure no longer drops and the reaction is stopped; (3) The viscous liquid obtained by vacuum distillation was placed in a high-pressure reactor, and the pH was adjusted to 3-4 with sulfuric acid. Aminosulfonic acid powder was added and heated with stirring at 130-140°C for 2-3 hours. The reaction was then cooled to below 40°C, 10 wt% ethanolamine was added, and the pH was adjusted to 7-8 with sodium hydroxide solution to obtain the product heavy oil viscosity reducer; Based on 1 mol part of nonylphenol, the amounts of 1-(4-fluorophenyl)piperazine, 40 wt% formaldehyde, ethylene oxide, and aminosulfonic acid are 1.6-2.4 mol parts, 3-5 mol parts, 2-20 mol parts, and 0.8-1.2 mol parts, respectively; The molecular structural formula of the heavy oil viscosity reducer is as follows: 。 2. The preparation method according to claim 1, characterized in that Based on 1 mol part of nonylphenol, the amounts of 1-(4-fluorophenyl)piperazine, 40 wt% formaldehyde, ethylene oxide, and aminosulfonic acid are 1.8-2.2 mol parts, 4-5 mol parts, 5-20 mol parts, and 0.9-1.1 mol parts, respectively.

3. The preparation method according to claim 1, characterized in that The weight ratio of water to nonylphenol in step (1) is 6-8:

1.

4. The preparation method according to claim 1, characterized in that The weight ratio of toluene to nonylphenol in step (2) is 4-6:

1.

5. The preparation method according to claim 1, characterized in that The weight ratio of sodium hydroxide to nonylphenol in step (2) is 0.2-0.3:

1.

6. The preparation method according to claim 1, characterized in that The weight ratio of 10 wt% ethanolamine to nonylphenol in step (3) is 3-5:

1.

7. The heavy oil viscosity reducer prepared according to the preparation method according to any one of claims 1 to 6.

8. Use of the heavy oil viscosity reducer according to claim 7 in improving the recovery rate of heavy oil.

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