Bio-based temperature-resistant salt-resistant microemulsion thick oil viscosity reducer and preparation method thereof

Abstract

The invention belongs to the technical field of oil exploitation, and particularly relates to a bio-based temperature-resistant salt-resistant microemulsion thick oil viscosity reducer and a preparation method thereof. The preparation method comprises the following steps: dissolving an electrolyte in water under heating and stirring conditions, then adding rapeseed polyphenol polyoxyethylene ether sodium carboxylate, and mixing to form a solution; and adding solvent oil into the solution, and dropwise adding an alcohol auxiliary agent under a stirring condition until the solution is transparent, so as to prepare the bio-based temperature-resistant salt-resistant microemulsion thick oil viscosity reducer. The microemulsion thick oil viscosity reducer has the advantages of simple single agent synthesis process, simple microemulsion preparation process, small dosage, good viscosity reduction effect, low cost and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil exploitation, and particularly relates to a bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer and a preparation method thereof. Background Art

[0002] As a strategic mineral resource, oil is related to the national economic lifeline and energy security. In recent years, China's external dependence on crude oil has remained high, and energy security and the stable development of the economy and society are facing major threats. However, most domestic oil fields, especially the old oil fields in the east, generally face the development characteristics of high water flooding recovery and high comprehensive water cut in conventional oil reservoirs, and it is difficult to further tap the potential. High-temperature and high-salt heavy oil reservoirs face development contradictions such as low recovery, high water cut, and low water flooding efficiency, and have great potential for tapping. At present, the oil displacement agents used for the development of conventional oil reservoirs are affected by high temperature and high salinity, and the oil displacement efficiency is low, which cannot meet the development needs of such oil reservoirs. Therefore, the development of temperature-resistant and salt-resistant heavy oil viscosity reducers is of great significance for improving the recovery rate of high-temperature and high-salt oil reservoirs.

[0003] Bio-based surfactants are a type of natural surfactants, including rapeseed polyphenols, lignin, cashew phenol, tannic acid, etc., and have the advantages of rich sources, economic renewability, good biocompatibility, etc. Among them, rapeseed polyphenols have the characteristics of wide sources and strong molecular structure plasticity, and will become an important raw material for the preparation of oilfield chemicals. Due to the poor water solubility of rapeseed polyphenols, molecular modification is usually carried out to improve their water solubility and surface and interfacial activity. In addition, the viscosity reduction effect of a single water-soluble surfactant on heavy oil is poor, and it needs to be prepared into a microemulsion viscosity reducer to improve its effect. However, the commonly used emulsion viscosity reducers currently use chemically synthesized surfactants that are not temperature-resistant and salt-resistant, resulting in poor adaptability of such viscosity reducers in high-temperature and high-salt oil reservoirs.

[0004] CN201210202927.4 discloses a microemulsion heavy oil viscosity reducer and a preparation method thereof. The weight ratio composition of the viscosity reducer is: 33-37 parts by weight of an oil-soluble viscosity reducer, 16-20 parts by weight of a non-ionic surfactant, 18-22 parts by weight of a sulfonate anionic surfactant, 2-4 parts by weight of a Tween-type emulsifier, 3-5 parts by weight of an isomeric alcohol, and 20-24 parts by weight of water. The above raw materials are used to prepare a product in a reaction kettle under certain temperature and rotation speed conditions. By preparing an aqueous solution of this microemulsion viscosity reducer with oilfield hot sewage and injecting it underground, it has the characteristics of high viscosity reduction rate and strong economy, and can reduce the viscosity of heavy oil by more than 98%. This invention uses a sulfonate anionic surfactant, which precipitates when encountering calcium and magnesium ions, so it is not suitable for high-salinity oil reservoirs.

[0005] Patent CN202310438189.1 discloses a preparation method of a compound surfactant heavy oil microemulsion. The components include the nonionic surfactant APE-9 and two amphoteric ionic surfactants CAB-35 and BS-12. This compound surfactant heavy oil microemulsion has the advantages of less surfactant dosage, low price, simple preparation method, and a viscosity reduction rate that can be as high as 99.53% - 99.68%, and can achieve the beneficial effect of improving oil recovery. However, this invention uses the nonionic surfactant APE-9 which is not temperature-resistant, so it is not applicable to high-temperature and high-salt oil reservoirs. Summary of the Invention

[0006] The present invention provides a bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer and its preparation method for the problem of poor adaptability of the current heavy oil viscosity reducer for high-temperature and high-salt oil reservoirs to the reservoir environment. The microemulsion viscosity reducer of the present invention has the advantages of simple single-agent synthesis process, simple microemulsion preparation process, less dosage, good viscosity reduction effect, and low cost.

[0007] Therefore, in order to achieve the above object, on the one hand, the present invention provides a bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer, and the composition and mass components of the microemulsion heavy oil viscosity reducer are as follows:

[0008]

[0009] The molecular structural formula of the sodium rapeseed polyphenol polyoxyethylene ether carboxylate is as follows:

[0010]

[0011] The solvent oil is one of 120#, 200#, 220#, 240#, 260#.

[0012] The electrolyte is one of NaCl, NaNO 3 , CaCl 2 one of them.

[0013] The alcohol co-agent is one of propanol, isopropanol, butanol, isobutanol, n-pentanol, n-hexanol.

[0014] On the other hand, the present invention provides a preparation method of a bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer, and the preparation method is as follows:

[0015] (1) Under heating and stirring conditions, dissolve the electrolyte in water, and then add sodium rapeseed polyphenol polyoxyethylene ether carboxylate to mix into a solution;

[0016] (2) Add the solvent oil to the above solution, and dropwise add the alcohol co-agent under stirring conditions until the solution becomes transparent to obtain the bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer.

[0017] The bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer of the present invention is a colorless and transparent liquid, which is composed of a water-soluble surfactant, a solvent oil, an alcohol assistant, and an electrolyte. As an emulsifier for preparing microemulsions, the sodium rapeseed polyphenol polyoxyethylene ether carboxylate synthesized in the present invention has both ethoxy groups and carboxyl groups on its molecule, and is a typical anionic-nonionic surfactant. The carboxyl group on its molecular structure can effectively weaken the precipitation problem caused by the high-temperature hydrogen bond interaction of the ethoxy group, so the temperature resistance is greatly improved. At the same time, the ethoxy group has a certain negative charge, which has a good electrostatic protection effect on the carboxylate group, reducing the interaction with divalent metal ions, so the calcium and magnesium ion resistance is improved. In addition, other components in the microemulsion have good temperature and salt resistance, so the prepared microemulsion can tolerate high-temperature and high-salt reservoir environments. Compared with water-soluble viscosity reducers, the present invention uses the strong emulsifying performance of sodium rapeseed polyphenol polyoxyethylene ether carboxylate to prepare a microemulsion with a nanoscale oil phase particle size, greatly improving the contact efficiency between the solvent oil and the heavy oil. During the contact process between the solvent oil and the heavy oil, the sodium rapeseed polyphenol polyoxyethylene ether carboxylate is brought into the oil phase. At this time, the methoxybenzene on the sodium rapeseed polyphenol polyoxyethylene ether carboxylate molecule can enter the colloid-asphaltene colloidal core structure in the heavy oil, destroying the strong interaction between the colloid and asphaltene, thereby simultaneously achieving emulsification viscosity reduction and dispersion viscosity reduction, greatly reducing the viscosity of the heavy oil and increasing the fluidity.

[0018] The beneficial effects and advantages of the present invention compared with the prior art:

[0019] (1) The rapeseed polyphenols used in the present invention for synthesizing sodium rapeseed polyphenol polyoxyethylene ether carboxylate have a wide source, the synthesis process is simple, and the process is clean and pollution-free;

[0020] (2) The bio-based microemulsion viscosity reducer of the present invention has good temperature and salt resistance, can withstand a temperature of 120 °C, the salt resistance concentration reaches 100000 mg / L, and the calcium and magnesium ion resistance concentration reaches 2000 mg / L;

[0021] (3) The bio-based microemulsion viscosity reducer of the present invention has good surface / interface properties, the surface tension is reduced to below 28 mN / m, and the interfacial tension is reduced to below 7×10 -2 mN / m;

[0022] (4) The bio-based microemulsion viscosity reducer of the present invention has the characteristics of high-efficiency viscosity reduction. Under the condition of a use concentration of 500 mg / L, the viscosity reduction rate of heavy oil with a viscosity within 100000 mPa·s can reach more than 99.0%. Specific embodiments

[0023] The endpoints and any values in the ranges disclosed herein are not limited to the exact 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 each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed herein.

[0024] According to the first aspect of the present invention, the present invention provides a bio-based temperature and salt-resistant microemulsion heavy oil viscosity reducer, and the composition and mass components of the microemulsion viscosity reducer are as follows:

[0025]

[0026] The molecular structural formula of the sodium rapeseed polyphenol polyoxyethylene ether carboxylate is as follows:

[0027]

[0028] The solvent oil is one of 120#, 200#, 220#, 240#, 260#.

[0029] The electrolyte is one of NaCl, NaNO 3 , CaCl 2 One of them.

[0030] The alcohol co-agent is one of propanol, isopropanol, butanol, isobutanol, n-pentanol, n-hexanol.

[0031] In the present invention, preferably, the solvent oil is one of 120#, 200#, 220#.

[0032] In the present invention, preferably, the electrolyte is NaCl or NaNO 3 .

[0033] In the present invention, preferably, the alcohol co-agent is one of propanol, isopropanol, butanol.

[0034] The sodium rapeseed polyphenol polyoxyethylene ether carboxylate is prepared from rapeseed polyphenols through two steps of etherification reaction and carboxylation reaction.

[0035] The preparation method of the sodium rapeseed polyphenol polyoxyethylene ether carboxylate is as follows:

[0036] (1) Put rapeseed polyphenols and a first catalyst into a reaction kettle at 30-40 °C; under high temperature, high pressure and anaerobic conditions, introduce ethylene oxide to carry out an etherification reaction, and then add acid for neutralization to obtain rapeseed polyphenol polyoxyethylene ether;

[0037] (2) Add the second catalyst to rapeseed polyphenol polyoxyethylene ether at 50 - 70 °C, and then add CH 2 CH 2 ClNaO 2 Carboxylation reaction occurs. After the reaction ends, add acid for neutralization, and extract with ethanol to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate.

[0038] In the invention, preferably, based on 1 mole part of rapeseed polyphenol, the dosages of the first catalyst and ethylene oxide are 0.01 - 0.1 mole part and 2 - 100 mole parts respectively.

[0039] More preferably, based on 1 mole part of rapeseed polyphenol, the dosages of the first catalyst and ethylene oxide are 0.01 - 0.03 mole part and 2 - 50 mole parts respectively.

[0040] In the invention, preferably, the first catalyst is one of solid sodium hydroxide, solid potassium hydroxide, and solid calcium hydroxide, and the mass ratio to rapeseed polyphenol is 0.02 - 0.1:1.

[0041] In the invention, preferably, the high temperature and high pressure are a temperature of 120 - 150 °C and a pressure of 0.1 - 0.4 MPa.

[0042] In the invention, preferably, the etherification reaction time is 1 - 10 h.

[0043] In the invention, preferably, based on 1 mole part of rapeseed polyphenol polyoxyethylene ether, the dosages of the second catalyst and CH 2 CH 2 ClNaO 2 are 0.02 - 0.1 mole part and 1 - 3 mole parts respectively.

[0044] More preferably, based on 1 mole part of rapeseed polyphenol polyoxyethylene ether, the dosages of the second catalyst and CH 2 CH 2 ClNaO 2 are 0.03 - 0.05 mole part and 1 - 2 mole parts respectively.

[0045] In the invention, preferably, the second catalyst is one of solid sodium hydroxide, solid potassium hydroxide, and solid calcium hydroxide, and the mass ratio to rapeseed polyphenol polyoxyethylene ether is 0.01 - 0.1:1.

[0046] In the invention, preferably, the carboxylation reaction time is 5 - 12 h.

[0047] According to a more specific preferred embodiment, the preparation method of sodium rapeseed polyphenol polyoxyethylene ether carboxylate specifically comprises the following steps:

[0048] (1) Add rapeseed polyphenols and the first catalyst into a high-pressure reactor, and stir at a constant temperature of 30 - 40 °C for 1 - 3 h;

[0049] (2) After the reaction is completed, flush with nitrogen to displace the air in the reactor, seal the high-pressure reactor, evacuate, introduce ethylene oxide, raise the temperature to 120 - 150 °C and increase the pressure to 0.1 - 0.4 MPa, and keep the temperature for reaction for 1 - 10 h; after the reaction is completed, cool to below 50 °C with circulating water, neutralize with 10 wt% hydrochloric acid to obtain rapeseed polyphenol polyoxyethylene ether;

[0050] (3) Add rapeseed polyphenol polyoxyethylene ether into a three-necked flask, flush with nitrogen to displace the air in the three-necked flask, stir and raise the temperature to 50 - 70 °C, then add sodium hydroxide, and stir at a constant temperature for 1 - 3 h; then add CH 2 CH 2 ClNaO 2 , react for 5 - 12 h; adjust the pH to 7 - 8 with 10 wt% hydrochloric acid, reflux the reaction solution in an ethanol solution for 2 - 3 h to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate.

[0051] The synthesis reaction equation of the sodium rapeseed polyphenol polyoxyethylene ether carboxylate is as follows:

[0052]

[0053] In a second aspect, the present invention provides a preparation method of a bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer, and the preparation method is as follows:

[0054] (1) Under heating and stirring conditions, dissolve the electrolyte in water, and then add sodium rapeseed polyphenol polyoxyethylene ether carboxylate to mix into a solution;

[0055] (2) Add solvent oil to the above solution, and dropwise add an alcohol assistant under stirring conditions until the solution becomes transparent to obtain a bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer.

[0056] Preferably, in step (1), the heating temperature is 20 - 40 °C and the stirring speed is 200 - 300 rpm.

[0057] Preferably, in step (2), the stirring speed is 200 - 300 rpm and the stirring time is 2 - 5 h.

[0058] In addition, it should be noted that, among the various specific technical features described in the above specific embodiments, without conflict, they can be combined in any suitable way. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0059] In addition, any combination can be made among various different embodiments of the present invention as long as it does not violate the idea of the present invention, and it should also be regarded as the content disclosed by the present invention.

[0060] The present invention will be further described below in conjunction with specific embodiments.

[0061] In the present invention, the devices or equipment used are all conventional devices or equipment known in the art and can be purchased.

[0062] In the following examples and comparative examples, without special instructions, various reagents used are all commercially available chemically pure reagents.

[0063] Example 1

[0064] (1) Add 1 mol of rapeseed polyphenol and 0.01 mol of solid sodium hydroxide into a high-pressure reactor, and stir at a constant temperature of 30 °C for 3 h;

[0065] (2) After the reaction is completed, flush with nitrogen to displace the air in the reactor, seal the high-pressure reactor, evacuate, introduce 2 mol of ethylene oxide, raise the temperature to 120 °C and the pressure to 0.3 MPa, and keep the temperature for 1 h; after the reaction is completed, cool to below 50 °C with circulating water, neutralize with 10 wt% hydrochloric acid to obtain rapeseed polyphenol polyoxyethylene ether;

[0066] (3) Add 1 mol of rapeseed polyphenol polyoxyethylene ether into a three-necked flask, flush with nitrogen to displace the air in the three-necked flask, stir and raise the temperature to 50 °C, then add 0.03 mol of solid sodium hydroxide, and stir at a constant temperature for 1 h; then add 1 mol of CH 2 CH 2 ClNaO 2 , react for 5 h; adjust the pH to 7 - 8 with 10 wt% hydrochloric acid, place the reaction solution in an ethanol solution and reflux for 2 h to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 1 .

[0067] Example 2

[0068] (1) Add 1 mol of rapeseed polyphenol and 0.02 mol of solid potassium hydroxide into a high-pressure reactor, and stir at a constant temperature of 32 °C for 2 h;

[0069] (2) After the reaction is completed, flush with nitrogen to displace the air in the reactor, seal the high-pressure reactor, evacuate, introduce 10 mol of ethylene oxide, raise the temperature to 125 °C and the pressure to 0.2 MPa, and keep the temperature for 2 h; after the reaction is completed, cool to below 50 °C with circulating water, neutralize with 10 wt% hydrochloric acid to obtain rapeseed polyphenol polyoxyethylene ether;

[0070] (3) Add 1 mol of rapeseed polyphenol polyoxyethylene ether into a three-necked flask, fill it with nitrogen to displace the air in the three-necked flask, stir and heat up to 60 °C, then add 0.04 mol of solid potassium hydroxide, and stir at a constant temperature for 3 h; subsequently add 1 mol of CH 2 CH 2 ClNaO 2 , react for 10 h; adjust the pH to 7 - 8 with 10 wt% hydrochloric acid, place the reaction solution in an ethanol solution and reflux for 2 h to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 2 .

[0071] Example 3

[0072] (1) Add 1 mol of rapeseed polyphenol and 0.05 mol of solid calcium hydroxide into a high-pressure reactor, and stir at a constant temperature of 35 °C for 1 h;

[0073] (2) After the reaction is completed, fill it with nitrogen to displace the air in the reactor, seal the high-pressure reactor, evacuate, introduce 20 mol of ethylene oxide, heat up to 140 °C and increase the pressure to 0.2 MPa, and keep the temperature for reaction for 3 h; after the reaction is completed, cool it to below 50 °C with circulating water, neutralize it with 10 wt% hydrochloric acid to obtain rapeseed polyphenol polyoxyethylene ether;

[0074] (3) Add 1 mol of rapeseed polyphenol polyoxyethylene ether into a three-necked flask, fill it with nitrogen to displace the air in the three-necked flask, stir and heat up to 55 °C, then add 0.04 mol of solid sodium hydroxide, and stir at a constant temperature for 2 h; subsequently add 2 mol of CH 2 CH 2 ClNaO 2 , react for 6 h; adjust the pH to 7 - 8 with 10 wt% hydrochloric acid, place the reaction solution in an ethanol solution and reflux for 3 h to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 3 .

[0075] Example 4

[0076] (1) Add 1 mol of rapeseed polyphenol and 0.06 mol of solid sodium hydroxide into a high-pressure reactor, and stir at a constant temperature of 36 °C for 1 h;

[0077] (2) After the reaction is completed, fill it with nitrogen to displace the air in the reactor, seal the high-pressure reactor, evacuate, introduce 50 mol of ethylene oxide, heat up to 130 °C and increase the pressure to 0.3 MPa, and keep the temperature for reaction for 5 h; after the reaction is completed, cool it to below 50 °C with circulating water, neutralize it with 10 wt% hydrochloric acid to obtain rapeseed polyphenol polyoxyethylene ether;

[0078] (3) Add 1 mol of rapeseed polyphenol polyoxyethylene ether into a three-necked flask, fill it with nitrogen to displace the air in the three-necked flask, stir and heat up to 65 °C, then add 0.05 mol of solid potassium hydroxide, and stir at a constant temperature for 3 h; subsequently, add 1.5 mol of CH 2 CH 2 ClNaO 2 , react for 8 h; adjust the pH to 7 - 8 with 10 wt% hydrochloric acid, place the reaction solution in an ethanol solution and reflux for 3 h to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 4 .

[0079] Example 5

[0080] (1) Add 1 mol of rapeseed polyphenol and 0.08 mo of solid potassium hydroxide into a high-pressure reactor, stir at a constant temperature of 38 °C for 2 h;

[0081] (2) After the reaction is completed, fill it with nitrogen to displace the air in the reactor, seal the high-pressure reactor, evacuate, introduce 80 mol of ethylene oxide, heat up to 135 °C and increase the pressure to 0.1 MPa, and keep the temperature for reaction for 8 h; after the reaction is completed, cool it to below 50 °C with circulating water, neutralize with 10 wt% hydrochloric acid to obtain rapeseed polyphenol polyoxyethylene ether;

[0082] (3) Add 1 mol of rapeseed polyphenol polyoxyethylene ether into a three-necked flask, fill it with nitrogen to displace the air in the three-necked flask, stir and heat up to 50 °C, then add 0.03 mol of solid calcium hydroxide, and stir at a constant temperature for 1 h; subsequently, add 1.6 mol of CH 2 CH 2 ClNaO 2 , react for 9 h; adjust the pH to 7 - 8 with 10 wt% hydrochloric acid, place the reaction solution in an ethanol solution and reflux for 2 h to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 5 .

[0083] Example 6

[0084] (1) Add 1 mol of rapeseed polyphenol and 0.1 mol of solid calcium hydroxide into a high-pressure reactor, stir at a constant temperature of 40 °C for 3 h;

[0085] (2) After the reaction is completed, fill it with nitrogen to displace the air in the reactor, seal the high-pressure reactor, evacuate, introduce 100 mol of ethylene oxide, heat up to 150 °C and increase the pressure to 0.4 MPa, and keep the temperature for reaction for 10 h; after the reaction is completed, cool it to below 50 °C with circulating water, neutralize with 10 wt% hydrochloric acid to obtain rapeseed polyphenol polyoxyethylene ether;

[0086] (3) Add 1 mol of rapeseed polyphenol polyoxyethylene ether into a three-necked flask, fill it with nitrogen to displace the air in the three-necked flask, stir and heat up to 70 °C, then add 0.05 mol of calcium hydroxide solid, and stir at a constant temperature for 2 h; then add 2 mol of CH 2 CH 2 ClNaO 2 , react for 12 h; adjust the pH to 7 - 8 with 10 wt% hydrochloric acid, place the reaction solution in an ethanol solution and reflux for 3 h to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 6 .

[0087] Example 7

[0088] (1) Add 25 g of water into a three-necked flask equipped with a stirrer and a thermometer, then add 5 g of NaC, stir and dissolve it at 20 °C and 300 revolutions per minute, and then add 10 g of sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 1 , and continue to stir to obtain a homogeneous solution;

[0089] (2) Add 20 g of 120# solvent oil to the above solution, and stir for 2 h at 200 revolutions per minute; at this temperature and rotation speed, slowly add 1 g of propanol until the solution becomes transparent to obtain the bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer B 1 .

[0090] Example 8

[0091] (1) Add 32 g of water into a three-necked flask equipped with a stirrer and a thermometer, then add 7 g of NaNO 3 , stir and dissolve it at 20 °C and 250 revolutions per minute, and then add 10 g of sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 2 , and continue to stir to obtain a homogeneous solution;

[0092] (2) Add 35 g of 200# solvent oil to the above solution, and stir for 2 h at 300 revolutions per minute; at this temperature and rotation speed, slowly add 2 g of isopropanol until the solution becomes transparent to obtain the bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer B 2 .

[0093] Example 9

[0094] (1) Add 35 g of water into a three-necked flask equipped with a stirrer and a thermometer, then add 7 g of CaCl 2 , stir and dissolve it at 40 °C and 200 revolutions per minute, and then add 10 g of sodium rapeseed polyphenol polyoxyethylene ether carboxylate A 3 , and continue to stir to obtain a homogeneous solution;

[0095] (2) Add 30 g of 200# solvent oil to the above solution and stir for 3 h at 200 revolutions per minute; at this temperature and rotation speed, slowly add 3 g of butanol dropwise until the solution becomes transparent to obtain the bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer B 3 。

[0096] Example 10

[0097] (1) Add 42 g of water to a three-necked flask equipped with a stirrer and a thermometer, then add 6 g of NaCl, stir and dissolve at 30 °C and 200 revolutions per minute, and then add 10 g of rapeseed polyphenol polyoxyethylene ether carboxylate A 4 ,continue to stir to obtain a homogeneous solution;

[0098] (2) Add 25 g of 220# solvent oil to the above solution and stir for 35 h at 250 revolutions per minute; at this temperature and rotation speed, slowly add 4 g of propanol dropwise until the solution becomes transparent to obtain the bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer B 4 。

[0099] Example 11

[0100] (1) Add 55 g of water to a three-necked flask equipped with a stirrer and a thermometer, then add 6 g of NaNO 3 ,stir and dissolve at 25 °C and 300 revolutions per minute, and then add 10 g of rapeseed polyphenol polyoxyethylene ether carboxylate A 5 ,continue to stir to obtain a homogeneous solution;

[0101] (2) Add 30 g of 240# solvent oil to the above solution and stir for 4 h at 280 revolutions per minute; at this temperature and rotation speed, slowly add 3 g of isopropanol dropwise until the solution becomes transparent to obtain the bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer B 5 。

[0102] Example 12

[0103] (1) Add 64 g of water to a three-necked flask equipped with a stirrer and a thermometer, then add 5 g of CaCl 2 ,stir and dissolve at 35 °C and 250 revolutions per minute, and then add 10 g of rapeseed polyphenol polyoxyethylene ether carboxylate A 6 ,continue to stir to obtain a homogeneous solution;

[0104] (2) Add 40 g of 260# solvent oil to the above solution and stir for 5 h at 300 revolutions per minute; at this temperature and rotation speed, slowly add 5 g of butanol dropwise until the solution becomes transparent to obtain the bio-based temperature-resistant and salt-resistant microemulsion heavy oil viscosity reducer B 6 。

[0105] Example 13: Test of Surface Tension and Interfacial Tension

[0106] The bio-based temperature and salt-resistant microemulsion heavy oil viscosity reducer B of the present invention 1 -B 3 and the petroleum sulfonate currently used in the oilfield were diluted to a 500 mg / L solution with the produced fluid from a certain block in Shengli Oilfield. The surface tension was measured by the ring method in SY / T 5370-2018 "Determination Method of Surface and Interfacial Tension", and the interfacial tension was tested by the pendant drop method. The viscosity of the crude oil in the test area at 50 °C was 93560 mPa·s, and the test results of the surface tension and interfacial tension are shown in Table 1.

[0107] It can be seen from Table 1 that the bio-based temperature and salt-resistant microemulsion heavy oil viscosity reducer B of the present invention 1 -B 3 when the use concentration is 500 mg / L, the surface tension is reduced to below 28 mN / m, and the interfacial tension is reduced to below 7×10 -2 mN / m, while the surface tension of the petroleum sulfonate in the comparative example is 30.5±1.1 mN / m, and the interfacial tension is (12.3±0.4)×10 -2 mN / m, which is significantly higher than that of the present invention.

[0108] Example 14: Determination of Viscosity Reduction Rate

[0109] The crude oil used in this experiment is the same as that in Example 13. The bio-based temperature and salt-resistant microemulsion heavy oil viscosity reducer B of the present invention 1 -B 3 and the petroleum sulfonate currently used in the oilfield were prepared into a 500 mg / L solution, and the evaluation method refers to Q / SH10201519—2016 "General Technical Conditions for Heavy Oil Viscosity Reducers"

[0110]

[0111] Wherein:

[0112] f——Viscosity reduction rate, %;

[0113] μ 0 ——Initial viscosity of crude oil at 50 °C, mPa·s;

[0114] μ——Viscosity of crude oil after viscosity reduction, mPa·s.

[0115] The test results are shown in Table 1.

[0116] It can be seen from Table 1 that the bio-based temperature and salt-resistant microemulsion heavy oil viscosity reducer B of the present invention 1 -B 3When the concentration is 500 mg / L, the viscosity reduction rate reaches over 99%, while the viscosity reduction rate of the petroleum sulfonate in the comparative example is 56.3 ± 0.5%, which is significantly lower than that of the present invention.

[0117] Example 15 Temperature and Salt Resistance Performance Test

[0118] (1) Prepare a 500 mg / L solution of the bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer B of the present invention 1 -B 3 and the petroleum sulfonate from Shengli Chemical Plant with distilled water, and then add NaCl and CaCl 2 so that their concentrations in the solution are 100000 mg / L and 2000 mg / L respectively. Place the prepared solution in an oven at 120 °C and let it stand for 24 h.

[0119] (2) Test the viscosity reduction rate of the crude oil in Example 13 according to the method of Example 14, and the test results are shown in Table 2.

[0120] As can be seen from Table 2: The bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer B of the present invention 1 -B 3 has good temperature and salt resistance performance, can withstand a temperature of 120 °C, the salt resistance concentration reaches 100000 mg / L, and the resistance to calcium and magnesium ion concentration reaches 2000 mg / L.

[0121] Example 10 Determination of Crude Oil Adaptability

[0122] (1) Prepare a 500 mg / L solution of the bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer B of the present invention 1 -B 3 and the petroleum sulfonate from Shengli Chemical Plant with the produced fluids from different blocks. The viscosity of the crude oil in Block 1 at 50 °C is 21563 mPa·s, the salinity is 12304 mg / L, and the calcium and magnesium ion concentration is 335 mg / L; the viscosity of the crude oil in Block 2 at 50 °C is 53689 mPa·s, the salinity is 36871 mg / L, and the calcium and magnesium ion concentration is 698 mg / L; the viscosity of the crude oil in Block 3 at 50 °C is 86048 mPa·s, the salinity is 63871 mg / L, and the calcium and magnesium ion concentration is 1056 mg / L;

[0123] (2) Test the viscosity reduction rate of the crude oil from different blocks according to the method of Example 14, and the test results are shown in Table 3.

[0124] As can be seen from Table 3: The bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer B of the present invention 1 -B 3 has a viscosity reduction rate of over 99% for crude oils with different salinities and viscosities, while the viscosity reduction rate of the petroleum sulfonate in the comparative example is less than 60%, indicating that the bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer of the present invention has strong adaptability.

[0125] Table 1 Test Results of Surface Tension, Interfacial Tension and Viscosity Reduction

[0126]

[0127]

[0128] Table 2 Test Results of Temperature and Salt Resistance Performance

[0129] Name Viscosity reduction rate, % <![CDATA[B 1 > 99.8±0.3 <![CDATA[B 2 > 99.9±0.4 <![CDATA[B 3 > 99.6±0.4 Petroleum sulfonate 32.5±0.3

[0130] Table 3 Viscosity Reduction Test Results of Bio-based Microemulsion Viscosity Reducer for Heavy Oil in Different Blocks

[0131]

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[0133] 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 bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer, characterized in that, the composition and mass components of the microemulsion heavy oil viscosity reducer are as follows: The molecular structural formula of the sodium rapeseed polyphenol polyoxyethylene ether carboxylate is as follows: The solvent oil is one of 120#, 200#, 220#, 240#, 260#; The electrolyte described above is one of NaCl, NaNO 3 , CaCl 2 ; The alcohol auxiliary agent is one of propanol, isopropanol, butanol, isobutanol, n-pentanol, n-hexanol.

2. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 1, characterized in that, the solvent oil is one of 120#, 200#, 220#.

3. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 1, characterized in that, The electrolyte described above is NaCl or NaNO 3 .

4. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 1, characterized in that, the alcohol auxiliary agent is one of propanol, isopropanol, butanol.

5. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 1, characterized in that, the preparation method of the sodium rapeseed polyphenol polyoxyethylene ether carboxylate is as follows: (1) Put rapeseed polyphenol and the first catalyst into the reaction kettle at 30 - 40°C; under high temperature, high pressure and anaerobic conditions, introduce ethylene oxide to carry out etherification reaction, and then add acid for neutralization to obtain rapeseed polyphenol polyoxyethylene ether; (2) Add the second catalyst to rapeseed polyphenol polyoxyethylene ether under the condition of 50-70 °C, and then add CH 2 CH 2 ClNaO 2 Carboxylation reaction occurs. After the reaction is completed, add acid for neutralization, and extract with ethanol to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate.

6. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 5, characterized in that, Based on 1 mole of rapeseed polyphenol, the dosages of the first catalyst and ethylene oxide are 0.01 - 0.1 mole and 2 - 100 moles respectively.

7. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 6, characterized in that, Based on 1 mole of rapeseed polyphenol, the dosages of the first catalyst and ethylene oxide are 0.01 - 0.03 mole and 2 - 50 moles respectively.

8. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 5, characterized in that, The first catalyst is one of solid sodium hydroxide, solid potassium hydroxide, solid calcium hydroxide, and the mass ratio with rapeseed polyphenol is 0.02 - 0.1:

1.

9. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 5, characterized in that, The high temperature and high pressure are at a temperature of 120 - 150°C and a pressure of 0.1 - 0.4 MPa.

10. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 5, characterized in that, The etherification reaction time is 1 - 10 h.

11. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 5, characterized in that, Based on 1 mole part of rapeseed polyphenol polyoxyethylene ether, the dosages of the second catalyst and CH 2 CH 2 ClNaO 2 are 0.02 - 0.1 mole part and 1 - 3 mole parts respectively.

12. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 11, characterized in that, Based on 1 mole part of rapeseed polyphenol polyoxyethylene ether, the dosages of the second catalyst and CH 2 CH 2 ClNaO 2 are 0.03 - 0.05 mole parts and 1 - 2 mole parts respectively.

13. The bio-based temperature- and salt-resistant microemulsion heavy oil viscosity reducer according to claim 5, characterized in that, The second catalyst is one of solid sodium hydroxide, solid potassium hydroxide, solid calcium hydroxide, and the mass ratio with rapeseed polyphenol polyoxyethylene ether is 0.01 - 0.1:

1.

14. A bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer according to claim 5, characterized in that, the carboxylation reaction time is 5 - 12 h.

15. A bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer according to claim 5, characterized in that, the preparation method specifically comprises the following steps: (1) Add rapeseed polyphenols and a first catalyst into a high-pressure reactor, and stir at a constant temperature of 30 - 40 °C for 1 - 3 h; (2) After the reaction is completed, flush nitrogen into the reactor to displace the air in the reactor, seal the high-pressure reactor, evacuate to vacuum, introduce ethylene oxide, raise the temperature to 120 - 150 °C and raise the pressure to 0.1 - 0.4 MPa, and keep the temperature for reaction for 1 - 10 h; after the reaction is completed, cool to below 50 °C with circulating water, add 10 wt% hydrochloric acid for neutralization to obtain rapeseed polyphenol polyoxyethylene ether; (3) Add rapeseed polyphenol polyoxyethylene ether into a three-necked flask, fill it with nitrogen to displace the air in the three-necked flask, stir and heat up to 50 - 70 °C, then add sodium hydroxide, and stir constantly at a constant temperature for 1 - 3 h; subsequently add CH 2 CH 2 ClNaO 2 , react for 5 - 12 h; adjust the pH to 7 - 8 with 10 wt% hydrochloric acid, place the reaction solution in an ethanol solution and reflux for 2 - 3 h to obtain the product sodium rapeseed polyphenol polyoxyethylene ether carboxylate.

16. A preparation method of a bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer, characterized in that, the preparation method is as follows: (1) Under heating and stirring conditions, dissolve the electrolyte in water, and then add sodium rapeseed polyphenol polyoxyethylene ether carboxylate to mix into a solution; (2) Add solvent oil to the above solution, and dropwise add an alcohol auxiliary agent under stirring conditions until the solution is transparent to obtain a bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer.

17. A preparation method of a bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer according to claim 16, characterized in that, in step (1), the heating temperature is 20 - 40 °C and the stirring speed is 200 - 300 rpm.

18. A preparation method of a bio-based temperature and salt resistant microemulsion heavy oil viscosity reducer according to claim 16, characterized in that, in step (2), the stirring speed is 200 - 300 rpm and the stirring time is 2 - 5 h.

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