Polymer as well as preparation method and application thereof

Abstract

The invention relates to the technical field of oilfield development, and discloses a polymer which simultaneously contains sulfonate groups, benzene rings and unsaturated double bonds. The molar ratio of the sulfonate group to the unsaturated double bond to the benzene ring is (3-8): (5-20): (10-120); the number average molecular weight of the polymer is 1000 to 15000 g / mol. The polymer as a viscosity reducer has extremely high resistance to high-concentration calcium and magnesium ions, has a good viscosity reduction effect on super-heavy oil, has good natural settling dehydration performance, can resist viscosity rebound, has good water solubility, is green and low-carbon, is simple in matched injection process, and is suitable for practical application in oil fields.

Description

Polymer and its preparation method and application

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of Chinese patent application 202211238976.3 filed on October 11, 2022, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the technical field of oilfield development, and in particular to a polymer, a preparation method and an application thereof. Background Art

[0004] Heavy oil is characterized by high viscosity, density, poor fluidity, temperature sensitivity, low light component content, and high levels of colloids and asphaltenes. Research indicates that crude oil can only be extracted and transported if its viscosity is below 400 mPa·s. Therefore, the core challenge in heavy oil extraction is how to effectively reduce its viscosity and improve its fluidity.

[0005] Existing heavy oil recovery includes thermal recovery and cold recovery. Among them, thermal recovery of heavy oil consumes a lot of energy and is high in cost; while cold recovery of heavy oil does not require heating. The method of achieving heavy oil viscosity reduction through the effects of chemical viscosity reducers, CO2 injection, microorganisms and external physical fields is becoming more and more widely used.

[0006] The representative heavy oil viscosity reduction technologies with current market application scale include:

[0007] The wellbore viscosity reduction method for ultra-heavy oil production uses a mixture of thin oil and a viscosity reducer. However, due to the significant price difference between thin oil and heavy oil, this method cannot achieve cost-effective oil recovery.

[0008] Emulsified super-heavy oil water-based viscosity reducers: Utilizing the synergistic effect of surfactant compounding, the overall surface activity is greatly enhanced, significantly reducing oil-water interfacial tension and thus reducing viscosity. However, this method requires the viscosity reducer to be mixed with the heavy oil for a long time under high-speed stirring conditions to achieve a viscosity reduction effect. After stopping stirring and allowing the heavy oil to stand for a long time, the viscosity of the heavy oil rebounds significantly, resulting in poor practical application results.

[0009] Polyglycerol ester-based heavy oil viscosity reducers: High-speed stirring can reduce the viscosity of heavy oils with viscosities between 2,000 and 60,000 mPa·s at 50°C. However, the reduction rate is only 28% to 75%, and the viscosity rebounds significantly after stirring is stopped and the mixture is allowed to stand.

[0010] In addition, the viscosity reducers currently used in heavy oil cold production have certain requirements on the concentration of calcium and magnesium ions in formation water, and their scope of use is quite limited.

[0011] Summary of the Invention

[0012] The present invention aims to overcome the problems of prior art in heavy oil, such as poor viscosity reduction and severe viscosity rebound after standing, in reservoirs with high calcium and magnesium ions. The present invention provides a polymer, a preparation method, and applications thereof. The polymer contains sulfonate groups, benzene rings, and unsaturated double bonds, which prevent the polymer from being completely encapsulated by the heavy oil, maintaining an oil / water interface in an oil-in-water state. Furthermore, the polymer has a low number-average molecular weight. When added to heavy oil, it improves the fluidity of the heavy oil and achieves viscosity reduction.

[0013] In order to achieve the above object, the first aspect of the present invention provides a polymer, wherein the polymer contains a sulfonate group, a benzene ring and an unsaturated double bond;

[0014] The molar ratio of the sulfonate group:unsaturated double bond:benzene ring is 3-8:5-20:10-120;

[0015] The number average molecular weight of the polymer is 1000-15000 g / mol.

[0016] A second aspect of the present invention provides a method for preparing a polymer, the method comprising: in the presence of an initiator, a catalyst and a surfactant, under anaerobic conditions, subjecting monomer A and monomer B to an emulsion polymerization reaction to obtain the polymer;

[0017] The monomer A contains a sulfonate group, and the monomer B contains a benzene ring and an unsaturated double bond;

[0018] Wherein, in the monomer B, the molar ratio of the unsaturated double bond to the benzene ring is 1:1-3.

[0019] The third aspect of the present invention provides a polymer prepared by the method described in the second aspect.

[0020] The fourth aspect of the present invention provides use of the polymers described in the first and third aspects as a viscosity reducer.

[0021] Through the above technical solution, the polymer provided by the present invention and its preparation method and application have the following beneficial effects:

[0022] (1) The polymer provided by the present invention contains sulfonic acid groups, benzene rings and unsaturated double bond structures and has a low number average molecular weight. It has a good viscosity reduction effect on super-heavy oil with a viscosity of 50,000-100,000 mPa·s, has high resistance to high concentrations of calcium and magnesium ions, good natural sedimentation and dehydration performance, can resist viscosity rebound, and has good water solubility. It is green and low-carbon, and the supporting injection process is simple, making it suitable for practical application in oil fields;

[0023] (2) Field applications show that the use of the polymer provided by the present invention significantly improves the fluidity of heavy oil. As the degassed viscosity of the heavy oil increases, the viscosity reduction effect gradually decreases. For heavy oil with a degassed viscosity not exceeding 100,000 mPa·s, the viscosity reduction rate reaches more than 99%. At the same time, when the concentrations of calcium and magnesium ions in the heavy oil are respectively less than 10,000 mg / L, the viscosity reduction rate remains basically unchanged. When the concentrations of calcium and magnesium ions in the heavy oil do not exceed 30,000 mg / L, the viscosity reducer has a good viscosity reduction effect. After the heavy oil has been allowed to stand for 4 hours, the natural sedimentation dehydration rate can still reach 91%. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] FIG1 is a 300 MHz H-NMR spectrum of the polymer of Example 1 in dimethyl sulfoxide (DOMSO) solvent;

[0025] FIG2 is an infrared spectrum of the polymer of Example 1. DETAILED DESCRIPTION

[0026] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0027] The first aspect of the present invention provides a polymer, wherein the polymer contains a sulfonate group, a benzene ring and an unsaturated double bond;

[0028] The molar ratio of the sulfonate group:unsaturated double bond:benzene ring is 3-8:5-20:10-120;

[0029] The number average molecular weight of the polymer is 1000-15000 g / mol.

[0030] According to a particularly preferred embodiment of the present invention, the molar ratio of the sulfonate group:unsaturated double bond:benzene ring is 3-8:5-20:20-80.

[0031] In the present invention, the benzene ring and the unsaturated double bond form a large π bond structure, that is, there is a C atom between the benzene ring and the unsaturated double bond. The unsaturated double bond is a carbon-carbon double bond C=C.

[0032] During their research, the inventors of the present invention discovered that the benzene rings and unsaturated C=C double bond structures in the polymer maintain a planar structure under the action of delocalized conjugation, making it easier to embed into the asphaltene interlayer structure in the heavy oil and weakening the strong π-π interaction. At the same time, the strong electrical properties of the sulfonate groups can attract water molecules through Coulomb force to form a nano-water film, so that the polymer is not completely wrapped by the heavy oil, maintaining the oil / water interface in a water-in-oil state, dissociating the aggregate structure of colloid and asphaltene in the heavy oil, achieving a good anti-viscosity rebound effect, and improving the fluidity of the heavy oil. When the molecular weight of the polymer meets the above range, the viscosity of the heavy oil can be reduced. After the degassed viscosity of the heavy oil is reduced, the bound water is more easily separated from the oil phase, and the natural sedimentation dehydration rate of the heavy oil can be improved.

[0033] At the same time, the sulfonate groups in the polymer are extremely hydrophilic, and the sulfonate group -SO3 - Ca 2+ Mg 2+ The generated calcium sulfonate and magnesium sulfonate are both easily soluble in water, which makes the polymer have extremely high calcium ion and magnesium ion resistance.

[0034] In the present invention, the degassed viscosity refers to the viscosity measured after crude oil is stirred to remove free water and bubbles therein.

[0035] According to a particularly preferred embodiment of the present invention, the molar ratio of the sulfonate group:unsaturated double bond:benzene ring is 4-6:6-12:24-48.

[0036] According to a particularly preferred embodiment of the present invention, the number average molecular weight of the polymer is 2000-8000 g / mol, preferably 2100-5800 g / mol.

[0037] In a preferred embodiment of the present invention, the molecular weight distribution of the polymer is 1.2-2, more preferably 1.2-1.6.

[0038] According to a preferred embodiment of the present invention, the polymer comprises a structural unit A and a structural unit B; the structural unit A has a structure shown in formula I; the structural unit B has a structure shown in formula II;

[0039] Wherein, in formula I, R1, R2, and R3 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, and M is an alkali metal element, an alkaline earth metal element, or NH4 + ; In formula II, R4, R5, R6, R7, R8, and R9 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, or substituted or unsubstituted aryl, and at least two of R4, R5, R6, R7, R8, and R9 are substituted or unsubstituted aryl.

[0040] In the present invention, the substituent in the "substituted aryl group" can be selected from C1-C3 alkyl groups, and the "unsubstituted aryl group" refers to a benzene ring.

[0041] In a particularly preferred embodiment of the present invention, in Formula I, R1, R2, and R3 are each independently selected from hydrogen, substituted or unsubstituted methyl, or substituted or unsubstituted ethyl; in Formula II, R6, R7, R8, and R9 are each independently a benzene ring, and R4 and R5 are each independently selected from hydrogen, substituted or unsubstituted methyl, or substituted or unsubstituted ethyl, that is, Formula II may be the structure shown in Formula (A):

[0042] More preferably, in Formula I, R1, R2, and R3 are hydrogen, and M is Na; in Formula II, R6, R7, R8, and R9 are each independently a benzene ring, and R4 and R5 are hydrogen.

[0043] In a preferred embodiment of the present invention, based on the total weight of the polymer, the content of the structural unit A is 10-50 wt%, and the content of the structural unit B is 50-90 wt%.

[0044] More preferably, based on the total weight of the polymer, the content of the structural unit A is 16-50 wt%, and the content of the structural unit B is 50-84 wt%.

[0045] A second aspect of the present invention provides a method for preparing a polymer, the method comprising: in the presence of an initiator, a catalyst and a surfactant, under anaerobic conditions, subjecting monomer A and monomer B to an emulsion polymerization reaction to obtain the polymer;

[0046] The monomer A contains a sulfonate group, and the monomer B contains a benzene ring and an unsaturated double bond;

[0047] Wherein, in the monomer B, the molar ratio of the unsaturated double bond to the benzene ring is 1:1-3.

[0048] In the present invention, monomer A containing a sulfonate group and monomer B containing a benzene ring and an unsaturated double bond are used for emulsion polymerization. The method is simple and the resulting polymer has a good anti-viscosity rebound effect when used for viscosity reduction of heavy oil, and improves the natural sedimentation dehydration rate of heavy oil.

[0049] In a specific embodiment of the present invention, the content of unreacted monomers in the system after the reaction is less than 0.1 wt %, which can be considered negligible. Therefore, in the present invention, it is considered that monomer A and monomer B are completely reacted.

[0050] In the present invention, the catalyst and surfactant can be added at any stage before the polymerization reaction.

[0051] According to one embodiment of the present invention, in parts by weight, the amount of monomer A is 10-30 parts, the amount of monomer B is 10-80 parts, the amount of initiator is 2-10 parts, the amount of catalyst is 1-5 parts, and the amount of surfactant is 1-3 parts.

[0052] In a more preferred embodiment of the present invention, based on parts by weight, the amount of monomer A is 15-25 parts, the amount of monomer B is 20-50 parts, the amount of initiator is 4-8 parts, the amount of catalyst is 2-4 parts, and the amount of surfactant is 2-3 parts.

[0053] According to one embodiment of the present invention, the initiator includes a water-soluble initiator and an oil-soluble initiator.

[0054] According to the present invention, the water-soluble initiator is at least one selected from azobisisobutylamidine hydrochloride, ammonium persulfate, potassium persulfate, sodium persulfate and azobisisobutylimidazoline hydrochloride, more preferably azobisisobutylamidine hydrochloride.

[0055] According to the present invention, the oil-soluble initiator is at least one selected from dibenzoyl peroxide, tert-butyl perbenzoate, azobisisobutyronitrile, and di-tert-butyl peroxide, more preferably dibenzoyl peroxide.

[0056] According to one embodiment of the present invention, the catalyst is selected from at least one of tetramethylethylenediamine, dimethylethylenediamine, acetylacetone, cyclopentadiene, TiCl4, TiCl3, VOI3 or VOCl3, preferably tetramethylethylenediamine.

[0057] According to one embodiment of the present invention, the surfactant is selected from at least one of Tween 20, Tween 40, Tween 60, polyethylene glycol 200 and Paregal O-20, preferably Paregal O-20.

[0058] According to one embodiment of the present invention, the polymerization reaction conditions are: temperature of 80-140° C., and time of 1-8 hours.

[0059] More preferably, the polymerization reaction conditions are: temperature of 90-120° C., and time of 1-5 h.

[0060] According to one embodiment of the present invention, the method further comprises quenching the emulsion polymerization reaction.

[0061] In the present invention, the polymerization reaction is subjected to inhibition and quenching treatment, so that the number average molecular weight of the prepared polymer is lower, thereby meeting the viscosity reduction rate requirement in heavy oil.

[0062] In one embodiment of the present invention, the quenching treatment is performed under stirring.

[0063] Preferably, the stirring speed is 1000-2200 rpm.

[0064] In the present invention, the inventors discovered that when the stirring speed exceeds 2200 rpm, the oil-water interface becomes too dispersed, the probability of individual monomer polymerization increases, the degree of interfacial polymerization decreases, and the viscosity-reducing activity of the resulting product decreases. Therefore, controlling the stirring speed to within the above range can achieve better results.

[0065] More preferably, the stirring speed is 1200-1900 rpm.

[0066] According to one embodiment of the present invention, the temperature of the quenching treatment is 0-15°C and the time is 10-80 minutes.

[0067] According to one embodiment of the present invention, the quenching treatment is performed by adding a polymerization inhibitor.

[0068] According to one embodiment of the present invention, the polymerization inhibitor is at least one selected from the group consisting of hydroquinone, 2-sec-butyl-4,6-dinitrophenol, sodium sulfate, sodium sulfide and ammonium thiocyanate, preferably hydroquinone.

[0069] According to one embodiment of the present invention, the amount of the polymerization inhibitor is 3-10 parts by weight, more preferably 6-8 parts, relative to 100 parts by weight of the monomer.

[0070] In a preferred embodiment of the present invention, the method further comprises: adding a polymerization inhibitor for quenching treatment, and then concentrating to obtain the polymer.

[0071] In one embodiment of the present invention, the concentration treatment is carried out at a temperature of 100-220° C. and for a time of 1-10 h.

[0072] In the present invention, the inventors discovered that concentration temperatures below 100°C result in excessively long concentration times, making later industrial production unfeasible. Concentration temperatures above 220°C risk polymer bond scission and degradation. For concentration times under 1 hour, the amount of water concentrated is too small, while for concentrations exceeding 10 hours, the water may evaporate to dryness, resulting in a hardened product. Therefore, controlling the concentration conditions within the above range can achieve better results.

[0073] Preferably, the concentration treatment is carried out at a temperature of 150-180° C. and for a time of 3-5 hours.

[0074] In the present invention, the catalyst and solvent are removed within the above-mentioned concentration treatment temperature range, and the surfactant is decomposed, volatilized or bond-broken within the same temperature range. The final polymer is free of catalyst and surfactant.

[0075] According to a particularly preferred embodiment of the present invention, the method for preparing the polymer comprises:

[0076] (1) mixing monomer A, a water-soluble hair agent, and a first solvent to obtain a first solution;

[0077] (2) mixing monomer B, an oil-soluble initiator, and a second solvent to obtain a second solution;

[0078] (3) in the presence of a catalyst and a surfactant, under anaerobic conditions, the first solution and the second solution are subjected to a polymerization reaction, and then a polymerization inhibitor is added for quenching to obtain the polymer;

[0079] Wherein, the monomer A is a compound having a structure shown in formula III, and the monomer B is a compound having a structure shown in formula IV;

[0080] Wherein, in formula III, R1', R2', R3' are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, M is an alkali metal element, an alkaline earth metal element or NH4 + ; In formula IV, R4', R5', R6', R7', R8', and R9' are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, or substituted or unsubstituted aryl, and at least two of R4', R5', R6', R7', R8', and R9' are substituted or unsubstituted aryl.

[0081] In the present invention, "substituted aryl" refers to an alkyl group whose substituents can be selected from C1-C3, and "unsubstituted aryl" refers to a benzene ring

[0082] In a particularly preferred embodiment of the present invention, in Formula IV, R6', R7', R8', and R9' are each independently a benzene ring, and R4' and R5' are each independently selected from hydrogen, a substituted or unsubstituted C1-C6 alkyl group, or a substituted or unsubstituted aryl group. That is, Formula IV may be represented by Formula (B):

[0083] In a preferred embodiment of the present invention, the first solvent is water.

[0084] In a preferred embodiment of the present invention, the second solvent is selected from at least one of toluene, xylene and kerosene, preferably toluene.

[0085] In a preferred embodiment of the present invention, relative to 100 parts by weight of the monomer, the amount of the first solvent used is 40-70 parts, and the amount of the second solvent used is 10-30 parts.

[0086] In a more preferred embodiment of the present invention, in formula III, R1', R2', and R3' are hydrogen, M is Na, and in formula IV, R4' and R5' are hydrogen. In this case, the monomer A is 2-acrylamide-2-methylpropanesulfonic acid sodium (AMPSNa), and the monomer B is 1,1,4,4-tetraphenyl-1,3-butadiene (1,1,4,4-Tp-1,3-Bd).

[0087] In a preferred embodiment of the present invention, the method for preparing the polymer comprises:

[0088] (1) mixing sodium 2-acrylamide-2-methylpropanesulfonate (AMPSNa), azobisisobutylamidine hydrochloride (AIBA), tetramethylethylenediamine (TEMED) and water to obtain a first solution, wherein, by weight, the amount of sodium 2-acrylamide-2-methylpropanesulfonate (AMPSNa) is 10-25 parts, the amount of azobisisobutylamidine hydrochloride (AIBA) is 1-5 parts, the amount of tetramethylethylenediamine (TEMED) is 1-5 parts, and the amount of water is 40-70 parts;

[0089] (2) mixing 1,1,4,4-tetraphenyl-1,3-butadiene (1,1,4,4-Tp-1,3-Bd), dibenzoyl peroxide (BPO), and toluene to obtain a second solution, wherein, by weight, the amount of 1,1,4,4-tetraphenyl-1,3-butadiene (1,1,4,4-Tp-1,3-Bd) is 10-60 parts, the amount of dibenzoyl peroxide (BPO) is 1-5 parts, and the amount of toluene is 10-30 parts;

[0090] (3) mixing the first solution, the second solution, and Peregal O-20, stirring uniformly, passing nitrogen to deoxygenate for 30-40 minutes, performing polymerization under anaerobic conditions, adding hydroquinone, quenching under stirring, and concentrating to obtain the polymer;

[0091] Wherein, by weight, the amount of peregal O-20 is 1-3 parts, and the amount of hydroquinone is 5-10 parts;

[0092] The polymerization reaction conditions are as follows: temperature of 90-120° C., time of 1-5 h; stirring speed of 1200-1900 rpm; temperature of quenching treatment of 0-10° C., time of 10-40 min; temperature of concentration treatment of 150-180° C., time of 1-10 h.

[0093] The third aspect of the present invention provides a polymer prepared by the method described in the second aspect.

[0094] The fourth aspect of the present invention provides use of the polymers described in the first and third aspects as a viscosity reducer.

[0095] In the present invention, the polymer is applied as a viscosity reducer to heavy oil. The application method includes dissolving the polymer in deionized water to prepare a viscosity reducer sample solution having a concentration of 1-5 wt%, and then adding the solution to the heavy oil to reduce viscosity. The mass ratio of the viscosity reducer sample solution to the heavy oil is 3:7-7:3.

[0096] According to the present invention, the polymer provided by the present invention is used as a viscosity reducer. Under the conditions of a use concentration of 3-5wt% and a maximum concentration of calcium ions or magnesium ions in the heavy oil of 30,000 mg / L, the viscosity reduction rate of heavy oil with a degassed viscosity of 50,000-100,000 mPa·s at 50°C can reach above 95%, preferably ≥99%, and the natural sedimentation dehydration rate is ≥85%. At the same time, the polymer has good anti-viscosity rebound performance, is green and low-carbon, and is suitable for practical application in oil fields.

[0097] The present invention will be described in detail below through examples. In the following examples, unless otherwise specified, all reagents used are commercially available;

[0098] The contents of structural unit A and structural unit B in the polymer were measured by NMR carbon spectroscopy;

[0099] The content of sulfonate groups in the polymer was determined by elemental analysis (EA), and the content of benzene rings and unsaturated double bonds was determined by NMR carbon spectroscopy;

[0100] The number average molecular weight and molecular weight distribution of the polymers were measured by gel permeation chromatography;

[0101] The degassed viscosity of heavy oil was measured using a Brookfield DVIII rotational viscometer;

[0102] The concentrations of calcium and magnesium ions were measured by titration.

[0103] Example 1

[0104] (1) 22 g of 2-acrylamide-2-methylpropanesulfonate sodium (AMPSNa), 2 g of azobisisobutylamidine hydrochloride (AIBA), 2 g of tetramethylethylenediamine (TEMED), and 60 g of water were mixed to obtain a first solution;

[0105] (2) 40 g of 1,1,4,4-tetraphenyl-1,3-butadiene (1,1,4,4-Tp-1,3-Bd), 4 g of dibenzoyl peroxide (BPO), and 20 g of toluene were mixed to obtain a second solution;

[0106] (3) The first solution, the second solution, and 2 g of peregal O-20 were mixed and stirred uniformly. The mixture was deoxygenated with nitrogen for 30 min. After polymerization under anaerobic conditions, 8 g of hydroquinone was added. The mixture was quenched with stirring and concentrated to obtain a viscous brown oil, designated as polymer A1, with a yield of 95.2%.

[0107] The polymerization reaction conditions were: 95°C for 5 hours, stirring at 1500 rpm, quenching at 0°C for 10 minutes, and concentration at 180°C for 3 hours. The resulting polymer had a number-average molecular weight of 5242 g / mol and a molecular weight distribution of 1.3.

[0108] In the polymer, the molar ratio of sulfonate group:unsaturated double bond:benzene ring is 5:6:24. Based on the total weight of the polymer, the content of the structural unit A is 35.5 wt %, and the content of the structural unit B is 64.5 wt %.

[0109] The 300 MHz H NMR spectrum of the polymer A1 in DOMSO solvent is shown in FIG1 , and the infrared spectrum of the polymer A1 is shown in FIG2 .

[0110] As can be seen from Figure 1, the shift at δ7.09-7.43ppm is the characteristic peak of the H atoms of the benzene ring in the 1,1,4,4-Tp-1,3-Bd monomer, the shift at δ6.01ppm is the shift of two H atoms in -C-CH=CH-C-, and the shifts at δ2.13ppm and δ1.12ppm are the characteristic peaks of three H atoms in -CH2-CH- in the AMPSNa monomer. Based on this analysis, butadiene is polymerized with the C=C of the AMPSNa monomer through the two terminal carbons, and the main chain structure is -[C-CH=CH-C]-[CH2-CH]-. At the same time, the shift at δ8.18ppm is the characteristic peak of -NH in the AMPSNa monomer, indicating that the amide bond is not hydrolyzed during the polymerization process and the long branched chain structure is still maintained.

[0111] As can be seen from Figure 2, 1763cm -1 The stretching vibration absorption peak of C=C in CC=CC group is 1011cm -1 The peak at -[C-CH=CH-C]-[CH2-CH]- is the stretching vibration absorption peak of C-CH2 after polymerization, which again shows that the two monomers are polymerized through 1,4-carbon atoms and C=C; 763cm -1 The peak at 3234 cm is the stretching vibration peak of the amide bond in the CO-NH group. -1 The peak at is the stretching vibration peak of the NH bond in the -NH group, which is consistent with the NMR, indicating that there is a long branched chain structure in the product.

[0112] Figures 1 and 2 illustrate that the main chain structure of polymer A1 is -[C-CH=CH-C]-[CH2-CH]-, and all the branched structures of the monomers are maintained.

[0113] Example 2

[0114] (1) 15 g of sodium 2-acrylamide-2-methylpropanesulfonate (AMPSNa), 4 g of azobisisobutylamidine hydrochloride (AIBA), 2 g of tetramethylethylenediamine (TEMED), and 60 g of water were mixed to obtain a first solution;

[0115] (2) 44 g of 1,1,4,4-tetraphenyl-1,3-butadiene (1,1,4,4-Tp-1,3-Bd), 2 g of dibenzoyl peroxide (BPO), and 20 g of toluene were mixed to obtain a second solution;

[0116] (3) The first solution, the second solution, and 2 g of peregal O-20 were mixed and stirred uniformly. The mixture was deoxygenated with nitrogen for 30 min. After polymerization under anaerobic conditions, 8 g of hydroquinone was added. The mixture was quenched with stirring and concentrated to obtain a viscous brown oil, designated as polymer A2, with a yield of 95.6%.

[0117] The polymerization reaction conditions were: 110°C for 2 hours, stirring at 1800 rpm, quenching at 0°C for 40 minutes, and concentration at 150°C for 5 hours. The resulting polymer had a number-average molecular weight of 3121 g / mol and a molecular weight distribution of 1.2.

[0118] In the polymer, the molar ratio of sulfonate group:unsaturated double bond:benzene ring is 3:6:24. Based on the total weight of the polymer, the content of the structural unit A is 25.4 wt %, and the content of the structural unit B is 74.6 wt %.

[0119] Example 3

[0120] (1) 22 g of sodium 2-acrylamide-2-methylpropanesulfonate (AMPSNa), 2 g of azobisisobutylamidine hydrochloride (AIBA), 2 g of tetramethylethylenediamine (TEMED), and 60 g of water were mixed to obtain a first solution;

[0121] (2) 22 g of 1,1,4,4-tetraphenyl-1,3-butadiene (1,1,4,4-Tp-1,3-Bd), 4 g of dibenzoyl peroxide (BPO), and 15 g of toluene were mixed to obtain a second solution;

[0122] (3) The first solution, the second solution, and 2 g of peregal O-20 were mixed and stirred uniformly. The mixture was deoxygenated with nitrogen for 30 min. After polymerization under anaerobic conditions, 6 g of hydroquinone was added. The mixture was quenched with stirring and concentrated to obtain a viscous brown oil, designated as polymer A3, with a yield of 97.8%.

[0123] The polymerization reaction conditions were: 120°C for 1 hour; 1800 rpm stirring; 5°C for 40 minutes quenching; and 180°C for 3 hours. The resulting polymer had a number-average molecular weight of 2302 g / mol and a molecular weight distribution of 1.2.

[0124] In the polymer, the molar ratio of sulfonate group:unsaturated double bond:benzene ring is 8:5:20. Based on the total weight of the polymer, the content of the structural unit A is 50 wt %, and the content of the structural unit B is 50 wt %.

[0125] Example 4

[0126] The method of Example 1 was followed, except that sodium 2-acrylamide-2-methylpropanesulfonate was replaced by potassium 2-acrylamide-2-methylpropanesulfonate, to finally obtain polymer A4 with a number average molecular weight of 6146 g / mol and a molecular weight distribution of 1.4.

[0127] Example 5

[0128] The method of Example 1 was followed, except that the amount of sodium 2-acrylamide-2-methylpropanesulfonate used was 10 g and the amount of 1,1,4,4-tetraphenyl-1,3-butadiene used was 70 g, to finally obtain polymer A5 with a number average molecular weight of 7400 g / mol and a molecular weight distribution of 1.5.

[0129] In the polymer, the molar ratio of sulfonate group:unsaturated double bond:benzene ring is 4:20:80. Based on the total weight of the polymer, the content of the structural unit A is 12.5 wt %, and the content of the structural unit B is 87.5 wt %.

[0130] Example 6

[0131] The method of Example 1 was followed, except that in step (3), the quenching temperature was 14° C. and the quenching time was 60 min. Finally, polymer A6 was obtained with a number average molecular weight of 7841 g / mol and a molecular weight distribution of 1.6.

[0132] Example 7

[0133] The method of Example 1 was followed, except that in step (3), the amount of hydroquinone used was 3 g, and polymer A7 was finally obtained with a number average molecular weight of 7863 g / mol and a molecular weight distribution of 1.6.

[0134] Example 8

[0135] The method of Example 1 was followed, except that 1,1,4,4-tetraphenyl-1,3-butadiene was replaced with 1,1,4,4-tetraphenyl-2,3-dimethyl-1,3-butadiene, to finally obtain polymer A8 with a number average molecular weight of 4678 g / mol and a molecular weight distribution of 1.4.

[0136] Example 9

[0137] The method of Example 1 was followed, except that in monomer A, R1' and R'2 were methyl groups, R3' was ethyl group, and M was Na. Finally, polymer A9 was obtained with a number average molecular weight of 5320 g / mol and a molecular weight distribution of 1.5.

[0138] In the polymer, the molar ratio of sulfonate group:unsaturated double bond:benzene ring is 4:6:24.

[0139] Example 10

[0140] The method of Example 1 was followed, except that the polymerization reaction conditions were: temperature 100° C., and time 1 h, to obtain polymer A10 with a number average molecular weight of 6721 g / mol and a molecular weight distribution of 1.6.

[0141] Example 11

[0142] The method of Example 1 was followed, except that the polymerization reaction conditions were: temperature 80° C., and time 30 min, to obtain polymer A11 with a number average molecular weight of 1126 g / mol and a molecular weight distribution of 1.6.

[0143] Example 12

[0144] The method of Example 1 was followed, except that the amount of hydroquinone used was 2 g, to finally obtain polymer A12 with a number average molecular weight of 14032 g / mol and a molecular weight distribution of 1.5.

[0145] Comparative Example 1

[0146] The 2-acrylamide-2-methylpropanesulfonic acid sodium monomer in Example 1 was replaced with the acrylamide monomer in Formula V, and polymerization was carried out according to the synthesis method in Example 1 to obtain polymer D1. The yield was 70.2%, and the obtained product had a number average molecular weight of 3642 g / mol and a molecular weight distribution of 2.

[0147] Comparative Example 2

[0148] The 1,1,4,4-tetraphenyl-1,3-butadiene monomer in Example 1 was replaced with the butadiene monomer in Formula VI, and polymerization was carried out according to the synthesis method in Example 1 to obtain polymer D2. The yield was 64.2%, the number average molecular weight of the obtained product was 2342 g / mol, and the molecular weight distribution was 1.7. H2C=CH-CH=CH2 Formula VI

[0149] Comparative Example 3

[0150] The method of Example 1 was followed, except that 22 g of 2-acrylamide-2-methylpropanesulfonic acid sodium (AMPSNa) was replaced with an equal amount of 2-acrylamide-2-methylpropanesulfonic acid (AMPS). The solution became micellar and the desired polymer could not be obtained.

[0151] Test Example 1

[0152] The polymers prepared in the examples and comparative examples were used as viscosity reducers at different concentrations to test the viscosity reduction rate of heavy oil samples with a degassed viscosity of 58120 mPa·s at 50°C. The viscosity reduction rate test method is as follows:

[0153] (1) Dissolve 1-5 g of the polymers prepared in the examples and comparative examples in 100 g of deionized water to prepare viscosity reducing agent sample solutions with a concentration of 1-5 wt %;

[0154] (2) Weigh 280 g of a heavy oil sample (viscosity measured as μ0) into a beaker, add 120 g of the viscosity reducer sample solution prepared in step (1), place the beaker in a constant temperature water bath at 50° C., maintain the constant temperature for 1 hour, place a stirring paddle in the center of the beaker and 2-3 mm away from the bottom, adjust the speed to 250 r / min, and stir for 2 minutes under constant temperature conditions to obtain a heavy oil emulsion;

[0155] (3) The viscosity μ of the above-mentioned heavy oil emulsion is measured using a rotational viscometer.

[0156] The viscosity reduction rate was calculated according to the formula f=(μ0-μ) / μ0×100%.

[0157] Where f is the viscosity reduction rate, μ0 is the viscosity of the heavy oil sample at 50°C, mPa·s, and μ0 is the viscosity of the heavy oil emulsion after adding the viscosity reducer sample solution, mPa·s.

[0158] The viscosity reduction results are shown in Table 1 and Table 1 (continued).

[0159] Table 1

[0160] Table 1 (continued)

[0161] As can be seen from Table 1 and Table 1 (Continued), the viscosity reduction rate increases with increasing viscosity reducer concentration. For example, when the concentration of viscosity reducer A1 increases from 4wt% to 5wt%, the viscosity reduction rate increases by only 0.3%. As can be expected, the increase in viscosity reduction rate will become less significant as the concentration of viscosity reducer continues to increase. Therefore, the maximum viscosity reducer concentration is optimized to 5wt%. At this maximum concentration, the viscosity reduction rate remains above 99%.

[0162] Polymers D1 and D2 that do not conform to the present invention have viscosity reduction rates of less than 60%. Polymers that do not meet the specific molecular weight range required by the present invention are also not effective for viscosity reduction.

[0163] Test Example 2

[0164] Using polymer A1 prepared in Example 1 at a concentration of 5 wt % as a viscosity reducer, viscosity reduction tests were conducted on heavy oil samples a, b, and c having degassed viscosities of 58120 mPa·s, 76800 mPa·s, and 93800 mPa·s at 50°C, respectively. The viscosity reduction results are shown in Table 2.

[0165] Table 2

[0166] As can be seen from Table 2, the viscosity-reducing effect of viscosity reducer A1 at a concentration of 5 wt% gradually decreases as the degassed viscosity of the heavy oil increases. When the degassed viscosity of the heavy oil is between 50,000 and 70,000 mPa·s, the viscosity reduction rate is 99.5%; when the degassed viscosity is between 70,000 and 90,000 mPa·s, the viscosity reduction rate is 99.3%; and when the degassed viscosity is between 90,000 and 100,000 mPa·s, the viscosity reduction rate is 99.1%. As expected, when the degassed viscosity of the heavy oil exceeds 100,000 mPa·s, the ultimate viscosity reduction rate of viscosity reducer A1 at a concentration of 5 wt% will fall below 99%. Therefore, for crude oils with a degassed viscosity of no more than 100,000 mPa·s, the polymer in Example 1 exhibits excellent viscosity-reducing effects as a viscosity reducer.

[0167] Test Example 3

[0168] Based on the viscosity reduction test results of Test Example 1, polymer A1 with a concentration of 5 wt% was used as a viscosity reducer to test the viscosity reduction rate of heavy oil sample c at different calcium and magnesium ion concentrations. The results are shown in Table 3.

[0169] Table 3

[0170] Table 3 (continued)

[0171] As shown in Table 3 and Table 3 (Continued), when the concentration of calcium and magnesium ions in the heavy oil is less than 10,000 mg / L, the viscosity reduction rate of the viscosity reducer remains unchanged; when the concentration of calcium ions in the heavy oil is not less than 10,000 mg / L, the viscosity reduction rate of the viscosity reducer remains unchanged, and when the concentration of magnesium ions in the heavy oil is not less than 10,000 mg / L, the viscosity reduction rate of the viscosity reducer decreases slightly. This shows that the polymer as a viscosity reducer has a stronger viscosity reduction effect on high-calcium ion heavy oil. When the concentration of calcium ions in the heavy oil exceeds 10,000 mg / L, the viscosity reduction rate of the viscosity reducer gradually decreases as its concentration increases. When the concentration of calcium ions reaches 30,000 mg / L, the degassed viscosity of the heavy oil after viscosity reduction is 844.2 mPa s, and the heavy oil still has a certain fluidity. When the concentration of calcium ions exceeds 30,000 mg / L, the degassed viscosity of the heavy oil after viscosity reduction exceeds 1000 mPa s, because high-concentration high-valent metal ions will produce strong electrostatic attraction with the sulfonate groups in the viscosity reducer, causing the viscosity reducer to gather more at the oil / water interface, reducing the embedded area of ​​conjugated aromatic hydrocarbons in asphaltene, and then weakening the viscosity reduction effect. Therefore, when the concentration of calcium and magnesium ions in the heavy oil does not exceed 30,000 mg / L, the polymer of the present invention has a good viscosity reduction effect as a viscosity reducer.

[0172] Test Example 4

[0173] The natural sedimentation dehydration rate and viscosity reduction rate after 6 hours of the heavy oil c after viscosity reduction at calcium and magnesium ion concentrations of 30,000 mg / L in Test Example 3 were measured using polymer A1 at a concentration of 5 wt%. The results are shown in Table 4.

[0174] Table 4 a、b Tested according to "Q / SLCG 0255-2018 Technical Requirements for Heavy Oil Cold Production Huff & Puff Viscosity Reducers"

[0175] As shown in Table 4, after standing for 4 hours, the natural sedimentation dehydration rates of heavy oil c reached 92% and 91%, respectively, under the conditions of calcium and magnesium ion concentrations of 30,000 mg / L, and were in a stable state without any reverse emulsification phenomenon. At the same time, the viscosity reduction rates were stable at 97.1% and 95.8%, and the deaerated viscosity of heavy oil c was maintained at around 4,000 mPa·s, which was significantly improved compared to the initial 93,800 mPa·s.

[0176] Furthermore, in Table 4, at a magnesium ion concentration of 30,000 mg / L, the viscosity reduction rate of polymer A1 at a concentration of 5 wt% after 6 hours was 95.8%. Compared to the initial viscosity reduction rate of 99.1% at a magnesium ion concentration of 30,000 mg / L in Table 3 (Continued), the crude oil degassing viscosity rebound rate was no more than 3.3% (99.1%-95.8%), indicating that the viscosity reducer has good stability in its viscosity reduction performance. Therefore, the viscosity reducer provided by the present invention has good natural sedimentation dehydration rate and viscosity rebound resistance, does not affect demulsification during gathering and transportation, and can ensure the sustained effect of viscosity reduction.

[0177] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A polymer, characterized in that The polymer contains sulfonate groups, benzene rings and unsaturated double bonds at the same time; The molar ratio of the sulfonate group:unsaturated double bond:benzene ring is 3-8:5-20:10-120; The number average molecular weight of the polymer is 1000-15000 g / mol.

2. The polymer according to claim 1, wherein The number average molecular weight of the polymer is 2000-8000 g / mol, preferably 2100-5800 g / mol; the molecular weight distribution is 1.2-2, preferably 1.2-1.

6.

3. The polymer according to claim 1 or 2, wherein A conjugated large π bond is formed between the benzene ring and the unsaturated double bond in the polymer.

4. The polymer according to any one of claims 1 to 3, wherein The polymer includes a structural unit A and a structural unit B; the structural unit A has a structure shown in formula I; the structural unit B has a structure shown in formula II; Wherein, in formula I, R1, R2, and R3 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, and M is an alkali metal element, an alkaline earth metal element, or NH4 + In formula II, R4, R5, R6, R7, R8, and R9 are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, and substituted or unsubstituted aryl, and at least two of R4, R5, R6, R7, R8, and R9 are substituted or unsubstituted aryl. More preferably, in the formula IV, R6, R7, R8, and R9 are each independently a benzene ring, and R4 and R5 are each independently selected from hydrogen, a substituted or unsubstituted C1-C6 alkyl group, or a substituted or unsubstituted aryl group.

5. The polymer according to claim 4, wherein In Formula I, R1, R2, and R3 are each independently selected from hydrogen, substituted or unsubstituted methyl, or substituted or unsubstituted ethyl; in Formula II, R6, R7, R8, and R9 are each independently a benzene ring, and R4 and R5 are each independently selected from hydrogen, substituted or unsubstituted methyl, or substituted or unsubstituted ethyl; Preferably, in Formula I, R1, R2, and R3 are hydrogen, and M is Na, K, or NH4 + , more preferably Na, in Formula II, R6, R7, R8, and R9 are each independently a benzene ring, and R4 and R5 are hydrogen.

6. The polymer according to claim 4 or 5, wherein Based on the total weight of the polymer, the content of the structural unit A is 10-50 wt%, and the content of the structural unit B is 50-90 wt%; Preferably, based on the total weight of the polymer, the content of the structural unit A is 16-50 wt%, and the content of the structural unit B is 50-84 wt%.

7. A method for preparing a polymer, characterized in that: The method comprises: in the presence of an initiator, a catalyst and a surfactant, under anaerobic conditions, conducting an emulsion polymerization reaction on monomer A and monomer B to obtain the polymer; The monomer A contains a sulfonate group, and the monomer B contains a benzene ring and an unsaturated double bond; Wherein, in the monomer B, the molar ratio of the unsaturated double bond to the benzene ring is 1:1-3.

8. The method according to claim 7, wherein: In parts by weight, the amount of monomer A is 10-30 parts, the amount of monomer B is 10-80 parts, the amount of initiator is 2-10 parts, the amount of catalyst is 1-5 parts, and the amount of surfactant is 1-3 parts.

9. The method according to claim 7 or 8, wherein The monomer A is a compound having a structure shown in formula III, and the monomer B is a compound having a structure shown in formula IV; Wherein, in formula III, R1', R2', R3' are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, M is an alkali metal element, an alkaline earth metal element or NH4 + In formula IV, R4', R5', R6', R7', R8', and R9' are each independently selected from hydrogen, substituted or unsubstituted C1-C6 alkyl, or substituted or unsubstituted aryl, and at least two of R4', R5', R6', R7', R8', and R9' are substituted or unsubstituted aryl. More preferably, in the formula IV, R6', R7', R8', and R9' are each independently a benzene ring, and R4' and R5' are each independently selected from hydrogen, a substituted or unsubstituted C1-C6 alkyl group, or a substituted or unsubstituted aryl group.

10. The method according to claim 7, 8 or 9, wherein: The initiator includes a water-soluble initiator and an oil-soluble initiator; Preferably, the water-soluble initiator is selected from at least one of azobisisobutylamidine hydrochloride, ammonium persulfate, potassium persulfate, sodium persulfate and azobisisobutylimidazoline hydrochloride, more preferably azobisisobutylamidine hydrochloride; Preferably, the oil-soluble initiator is at least one selected from dibenzoyl peroxide, tert-butyl perbenzoate, azobisisobutyronitrile, and di-tert-butyl peroxide, more preferably dibenzoyl peroxide.

11. The method according to any one of claims 7 to 10, wherein: The catalyst is selected from at least one of tetramethylethylenediamine, dimethylethylenediamine, acetylacetone, cyclopentadiene, TiCl4, TiCl3, VOI3 or VOCl3, preferably tetramethylethylenediamine.

12. The method according to any one of claims 7 to 11, wherein: The surfactant is selected from at least one of Tween 20, Tween 40, Tween 60, polyethylene glycol 200 and Paregal O-20, preferably Paregal O-20.

13. The method according to any one of claims 7 to 12, wherein: The polymerization reaction conditions are: temperature of 80-140° C. and time of 1-8 hours.

14. The method according to any one of claims 7 to 13, wherein: The method further comprises quenching the emulsion polymerization reaction; Preferably, the quenching treatment is carried out at a temperature of 0-15°C and for a time of 10-80 minutes.

15. The method according to any one of claims 7 to 14, wherein: Quenching treatment is performed by adding a polymerization inhibitor; Preferably, the polymerization inhibitor is at least one selected from the group consisting of hydroquinone, 2-sec-butyl-4,6-dinitrophenol, sodium sulfate, sodium sulfide and ammonium thiocyanate, preferably hydroquinone; Preferably, the amount of the polymerization inhibitor is 3-10 parts by weight relative to 100 parts by weight of the monomer.

16. A polymer obtained by the preparation method according to any one of claims 7 to 15.

17. Use of the polymer according to any one of claims 1 to 6 and 16 as a viscosity reducer.

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