Polymer for oil extraction of high-temperature and high-salinity oil reservoir and preparation method and application thereof
1. The polymer for oil extraction of the high-temperature and high-salinity oil reservoir is characterized by comprising the following components: an organic carboxylic acid monomer unit containing an acrylimide group, an acrylamide monomer unit, an N-alkyl substituted acrylamide sulfonic acid monomer unit and a polyalcohol monomer unit containing a vinylaniline group;
the carbon number of the alkyl in the N-alkyl substituted acrylamide sulfonic acid monomer unit is 6-19;
the molar ratio of the organic carboxylic acid monomer unit containing the acrylimide group, the acrylamide monomer unit, the N-alkyl substituted acrylamide sulfonic acid monomer unit and the polyalcohol monomer unit containing the vinylaniline group is (1-10): (15-45): (0.4-6): (0.4-3).
2. The polymer for oil recovery of high-temperature and high-salinity reservoir according to claim 1, is characterized by comprising blocks shown in formula (I), formula (II), formula (III) and formula (IV):
wherein, p: x: y: z is (1-10): (15-45): (0.4-6): (0.4 to 3);
m is an integer of 1-4, n is an integer of 1-5;
r is C6-C19 alkyl;
r' is hydrogen or methyl.
3. The polymer for oil recovery of high-temperature and high-salinity oil reservoir according to claim 2, wherein n is an integer of 1-4; r is C12-C16 alkyl.
4. The polymer for oil recovery of high-temperature and high-salinity reservoir according to claim 2, wherein n is an integer of 1 to 4, and R is C12 alkyl or C16 alkyl.
5. The preparation method of the polymer for oil recovery of the high-temperature and high-salinity reservoir according to claim 1, is characterized by comprising the following steps:
s1) mixing an organic carboxylic acid monomer containing an acrylimide group, an acrylamide monomer, an N-alkyl substituted acrylamide sulfonic acid monomer, a polyalcohol monomer containing a vinylaniline group, a stabilizer, a chain transfer agent and a cosolvent in water, deoxidizing, adding an initiator, and carrying out polymerization reaction to obtain a rubber block;
s2) hydrolyzing the gel block to obtain the polymer for high-temperature and high-salinity oil reservoir oil extraction.
6. The preparation method according to claim 5, wherein the step S1) is specifically:
A) mixing a solubilizer water solution with an N-alkyl substituted acrylamide sulfonic acid monomer to obtain a solution A;
mixing an organic carboxylic acid monomer containing an acrylimide group, an acrylamide monomer, a polyalcohol monomer containing a vinylaniline group and water to obtain a solution B;
B) and adjusting the pH value of the solution B to 6-8, adding the solution A, a stabilizer, a chain transfer agent and a cosolvent, deoxidizing, adding an initiator, and carrying out polymerization reaction to obtain the rubber block.
7. The preparation method according to claim 6, wherein the mass ratio of the organic carboxylic acid monomer containing an acryloyl group, the acrylamide monomer, the N-alkyl substituted acrylamide sulfonic acid monomer and the polyalcohol monomer containing a vinylaniline group is (13-30): (50-90): (5-19): (6-28);
the mass ratio of the acrylamide monomer to water in the step A) is (50-90): (200-1150).
8. The method according to claim 7, wherein the aqueous solution of the solubilizing agent is an aqueous solution of sodium lauryl sulfate;
the stabilizer is disodium ethylene diamine tetraacetate;
the chain transfer agent is selected from one or more of dodecyl mercaptan, isopropanol, sodium formate and sodium bisulfite;
the cosolvent is selected from one or more of carbamide, sodium propenyl sulfonate and sodium methyl propenyl sulfonate;
the initiator is a composite initiator of persulfate-sulfite and azobisisobutylamidine hydrochloride.
9. The preparation method according to claim 8, wherein the mass ratio of the acrylamide monomer, the stabilizer, the chain transfer agent and the cosolvent is (50-90): (0.01-1): (0.001-0.1): (0.01 to 1);
in the initiator, the mass ratio of persulfate to sulfite to azodiisobutyl amidine hydrochloride is (0.05-1.2): (0.025-0.6): (0.08-2.3);
the polymerization reaction is carried out under the condition of closed heat insulation;
the temperature for the polymerization reaction to start is 2-12 ℃; the time of the polymerization reaction is 3-7 h.
10. The polymer for high-temperature and high-salinity reservoir oil recovery according to any one of claims 1 to 4 or the polymer prepared by the preparation method according to any one of claims 5 to 9 is applied to a high-temperature reservoir and/or a high-salinity reservoir.
Background
Along with the deep exploration and development degree of each large oil field in China, the exploitation difficulty is gradually increased, and most of the oil fields enter a high-water-content exploitation stage. In order to efficiently excavate residual oil and residual oil in a submerged oil reservoir, a polymer flooding tertiary oil recovery technology is produced, and mine field tests and industrial popularization and application are successively carried out in oil fields of Daqing, Dagang, Henan, Shengli, Xinjiang and the like, and remarkable economic benefits are obtained.
The polymer flooding is mainly characterized in that the viscosity of injected stratum fluid is increased, the oil-water fluidity ratio is changed, the follow-up liquid flow is forced to change direction, and the sweep coefficient of the injected fluid is improved; meanwhile, oil drops are stripped from the surface of the rock by means of the viscoelasticity of the polymer, and the oil washing effect is improved. However, in practical production application, some defects which are difficult to overcome exist: under the condition of high temperature, the polymer can be obviously thermally degraded, the original stability is lost, and the oil displacement effect is greatly weakened; the high-salt environment is not beneficial to the dissolution and hydration of the polymer, the hydrolysis degree of the polymer is increased along with the prolonging of the aging time, the polymer is easy to precipitate under the action of high-valence metal ions such as calcium, magnesium and the like, and the oil displacement capacity is lost, and mine field test researches show that the reduction rate of the apparent viscosity of the polymer before and after the polymer is injected into a pump machine reaches about 15-35 percent; in addition, the polymer can be adsorbed and retained in the near wellbore area, so that the pumping pressure of subsequent medicaments is greatly increased, and the exploitation cost is increased.
In view of the fact that the self-performance limitation of the existing industrialized polymer can not meet the requirement of improving the recovery ratio of the oil field, the existing polymer is urgently needed to be modified, a plurality of functional monomers with different structures are introduced to the main chain of the polymer through copolymerization, the intramolecular and intermolecular actions are changed, and the novel high-temperature high-salinity oil reservoir oil extraction polymer which is good in tackifying performance, excellent in temperature resistance and salt resistance and capable of being widely applied to the field of oil extraction is developed.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a polymer for oil recovery in a high-temperature high-salt oil reservoir, a preparation method and an application thereof, wherein the polymer has low initial viscosity, good pump injection performance, excellent temperature and salt resistance, long effective stability period when acting on a high-temperature or high-salt oil reservoir, and good oil displacement effect; the surfactant is applied to certain Russian oil field blocks, has good compatibility with corresponding surfactants, and has obvious oil washing effect.
The invention provides a polymer for high-temperature and high-salinity reservoir oil extraction, which comprises the following components: an organic carboxylic acid monomer unit containing an acrylimide group, an acrylamide monomer unit, an N-alkyl substituted acrylamide sulfonic acid monomer unit and a polyalcohol monomer unit containing a vinylaniline group;
the carbon number of the alkyl in the N-alkyl substituted acrylamide sulfonic acid monomer unit is 6-19;
the molar ratio of the organic carboxylic acid monomer unit containing the acrylimide group, the acrylamide monomer unit, the N-alkyl substituted acrylamide sulfonic acid monomer unit and the polyalcohol monomer unit containing the vinylaniline group is (1-10): (15-45): (0.4-6): (0.4-3).
Preferably, it comprises blocks of formula (I), formula (II), formula (III) and formula (IV):
wherein, p: x: y: z is (1-10): (15-45): (0.4-6): (0.4 to 3);
m is an integer of 1-4, n is an integer of 1-5;
r is C6-C19 alkyl;
r' is hydrogen or methyl.
Preferably, n is an integer of 1-4; r is C12-C16 alkyl.
Preferably, n is an integer of 1-4, and R is C12 alkyl or C16 alkyl.
The invention also provides a preparation method of the polymer for oil extraction of the high-temperature and high-salinity oil reservoir, which comprises the following steps:
s1) mixing an organic carboxylic acid monomer containing an acrylimide group, an acrylamide monomer, an N-alkyl substituted acrylamide sulfonic acid monomer, a polyalcohol monomer containing a vinylaniline group, a stabilizer, a chain transfer agent and a cosolvent in water, deoxidizing, adding an initiator, and carrying out polymerization reaction to obtain a rubber block;
s2) hydrolyzing the gel block to obtain the polymer for high-temperature and high-salinity oil reservoir oil extraction.
6. The preparation method according to claim 5, wherein the step S1) is specifically:
A) mixing a solubilizer water solution with an N-alkyl substituted acrylamide sulfonic acid monomer to obtain a solution A;
mixing an organic carboxylic acid monomer containing an acrylimide group, an acrylamide monomer, a polyalcohol monomer containing a vinylaniline group and water to obtain a solution B;
B) and adjusting the pH value of the solution B to 6-8, adding the solution A, a stabilizer, a chain transfer agent and a cosolvent, deoxidizing, adding an initiator, and carrying out polymerization reaction to obtain the rubber block.
Preferably, the mass ratio of the organic carboxylic acid monomer containing the acrylimide group, the acrylamide monomer, the N-alkyl substituted acrylamide sulfonic acid monomer and the polyalcohol monomer containing the vinylaniline group is (13-30): (50-90): (5-19): (6-28);
the mass ratio of the acrylamide monomer to water in the step A) is (50-90): (200-1150).
Preferably, the aqueous solution of the solubilizer is an aqueous solution of sodium dodecyl sulfate;
the stabilizer is disodium ethylene diamine tetraacetate;
the chain transfer agent is selected from one or more of dodecyl mercaptan, isopropanol, sodium formate and sodium bisulfite, preferably sodium formate;
the cosolvent is selected from one or more of carbamide, sodium propenyl sulfonate and sodium methyl propenyl sulfonate, and is preferably sodium methyl propenyl sulfonate;
the initiator is a composite initiator of persulfate-sulfite and azobisisobutylamidine hydrochloride.
Preferably, the mass ratio of the acrylamide monomer, the stabilizer, the chain transfer agent and the cosolvent is (50-90): (0.01-1): (0.001-0.1): (0.01 to 1);
in the initiator, the mass ratio of persulfate to sulfite to azodiisobutyl amidine hydrochloride is (0.05-1.2): (0.025-0.6): (0.08-2.3);
the polymerization reaction is carried out under the condition of closed heat insulation;
the temperature for the polymerization reaction to start is 2-12 ℃; the time of the polymerization reaction is 3-7 h.
The invention also provides application of the polymer for oil recovery of the high-temperature and high-salinity reservoir in the high-temperature reservoir and/or the high-salinity reservoir.
The invention provides a polymer for high-temperature and high-salinity reservoir oil extraction, which comprises the following components: an organic carboxylic acid monomer unit containing an acrylimide group, an acrylamide monomer unit, an N-alkyl substituted acrylamide sulfonic acid monomer unit and a polyalcohol monomer unit containing a vinylaniline group; the carbon number of the alkyl in the N-alkyl substituted acrylamide sulfonic acid monomer unit is 6-19; the molar ratio of the organic carboxylic acid monomer unit containing the acrylimide group, the acrylamide monomer unit, the N-alkyl substituted acrylamide sulfonic acid monomer unit and the polyalcohol monomer unit containing the vinylaniline group is (1-10): (15-45): (0.4-6): (0.4-3). Compared with the prior art, the main chain of the polymer molecule provided by the invention is of a carbon chain structure, and the functional monomer is directly polymerized onto the main chain of the polyacrylamide, so that the molecular structure is stable; the imide group in the organic carboxylic acid monomer unit has a certain inhibiting effect on imidization crosslinking of the product, the solubility of the product can be improved, meanwhile, the monomer unit has a strong molecular chelation effect on divalent ions, and the chelation effect is enhanced due to the ortho-group effect of adjacent amide units; the polymer introduces N-alkyl substituted acrylamide sulfonic acid monomer units, the viscosity of the polymer can be improved by adjusting the length of alkyl carbon chains, the intermolecular association can be further influenced by the block distribution and the length of the monomer units on the main chain of the copolymer, and the comprehensive action of the monomer units and the main chain enables the copolymerization products to have certain strength and reversible association among molecules, thereby effectively constructing a three-dimensional network structure and enhancing the shear resistance of the polymer; the polymer also introduces a vinyl aniline group-containing polyol monomer unit, so that the space volume of a repeating unit of the polymer is increased, the steric hindrance effect is enhanced, the probability of molecular long chain breakage is reduced due to the existence of phenyl and other rigid monomers, and the polymer can keep stable performance for a long time at high temperature.
In addition, the strong hydrophilicity and the electrostatic repulsion action of carboxyl, alcoholic hydroxyl and sulfonic group in the molecular structure greatly increase the water solubility of the polymer and the hydrodynamic volume of a molecular chain, and show good tackifying property; wherein-SO3 -Has high charge density, can improve the salt resistance of the polymer, particularly does not generate precipitation with divalent cations, and inhibits-CONH to a certain extent2Thereby improving the stability of the product group. The chain transfer agent and the cosolvent have a synergistic effect, so that chain transfer of free radicals to tertiary carbon is avoided, the branching or crosslinking of the product is further controlled, meanwhile, direct hydrogen bond association among the product molecules is dispersed to a certain degree, and the dissolution and tackifying properties and the salt resistance of the product are improved.
Experiments show that the high-temperature and high-salinity reservoir provided by the invention is used for oil extractionThe polymer acts on high temperature (86-120 ℃) or high salt (C)>40000mg·L-1，Ca2+、Mg2+>2000mg·L-1) During oil deposit, the oil displacement effect is good compared with other oil extraction polymers under the same condition; under the oil reservoir conditions of a certain area in Russia (the oil reservoir temperature is 86 ℃, the formation water mineralization is 20000 mg.L-1) The surface tension of the formed polyepithelial binary complex system can still reach 10 ultra-low surface tension after 3 months due to good compatibility with corresponding surfactants-3mN/m, and the oil washing effect is obvious.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a polymer for high-temperature and high-salinity reservoir oil extraction, which comprises the following components: an organic carboxylic acid monomer unit containing an acrylimide group, an acrylamide monomer unit, an N-alkyl substituted acrylamide sulfonic acid monomer unit and a polyalcohol monomer unit containing a vinylaniline group;
the carbon number of the alkyl in the N-alkyl substituted acrylamide sulfonic acid monomer unit is 6-19;
the molar ratio of the organic carboxylic acid monomer unit containing the acrylimide group, the acrylamide monomer unit, the N-alkyl substituted acrylamide sulfonic acid monomer unit and the polyalcohol monomer unit containing the vinylaniline group is (1-10): (15-45): (0.4-6): (0.4-3).
Wherein the acryloyl imine group-containing organic carboxylic acid monomer unit is preferably a block represented by formula (I):
m is preferably an integer of 1 to 4, i.e., m is 1, 2, 3 or 4.
The acrylamide monomer unit is preferably an acrylamide monomer unit or a methacrylamide monomer unit, and is a block represented by the formula (II):
r' is preferably hydrogen or methyl.
The N-alkyl substituted acrylamide sulfonic acid monomer unit is preferably a block represented by the formula (III):
r is preferably C6-C19 alkyl, more preferably C8-C19 alkyl, still more preferably C10-C18 alkyl, and most preferably C12-C16 alkyl; in some embodiments provided herein, R is specifically a C12 or C16 alkyl group.
The vinylanilino-containing polyol monomer units are preferably blocks represented by the formula (IV):
n is preferably an integer of 1 to 5, more preferably an integer of 1 to 4; in the examples provided by the present invention, n is specifically 1, 2, 3 or 4.
In the invention, the polymer for oil recovery of the high-temperature and high-salinity reservoir most preferably comprises blocks shown in a formula (I), a formula (II), a formula (III) and a formula (IV); the blocks shown in the formula (I), the formula (II), the formula (III) and the formula (IV) are the same as above, and are not described again; the p: x: y: z is preferably (1-10): (15-45): (0.4-6): (0.4 to 3), more preferably (1 to 8): (15-40): (0.4-4): (0.4-3), and more preferably (1-5): (15-35): (0.4-3): (0.8-3), and more preferably (1-3): (15-30): (0.4-2): (0.8-2), most preferably (1-2.5): (15-25): (0.4-1): (1-2).
According to the invention, the degree of polymerization of the block of formula (I) is preferably between 0.1 and 10 ten thousand; the polymerization degree of the block represented by the formula (II) is preferably 1.5 to 45 ten thousand; the polymerization degree of the block represented by the formula (III) is preferably 0.04 to 6 ten thousand; the polymerization degree of the block represented by the formula (IV) is preferably 0.04 to 3 ten thousand.
The cation in the polymer for oil recovery of the high-temperature and high-salinity reservoir provided by the invention is preferably sodium ion.
According to the invention, the relative molecular weight of the polymer for oil recovery of the high-temperature and high-salinity reservoir is preferably 1 x 106～1×108More preferably 5X 106～5×107And still more preferably 5X 106～3×107Most preferably 8X 106～2×107(ii) a In the embodiment provided by the invention, the relative molecular weight of the polymer for oil recovery of the high-temperature and high-salinity reservoir is specifically 8.86 multiplied by 106、1.19×107、1.48×107Or 1.81X 107。
The invention also provides a preparation method of the polymer for oil extraction of the high-temperature and high-salinity oil reservoir, which comprises the following steps: s1) mixing an organic carboxylic acid monomer containing an acrylimide group, an acrylamide monomer, an N-alkyl substituted acrylamide sulfonic acid monomer, a polyalcohol monomer containing a vinylaniline group, a stabilizer, a chain transfer agent and a cosolvent in water, deoxidizing, adding an initiator, and carrying out polymerization reaction to obtain a rubber block; s2) hydrolyzing the gel block to obtain the polymer for high-temperature and high-salinity oil reservoir oil extraction.
The polymer provided by the invention has low initial viscosity, good pump injection performance, excellent temperature resistance and salt resistance, and good compatibility with a surfactant, and the formed polymer-surfactant binary composite system has the interfacial tension which can still reach 10 ultralow interfacial tension after 3 months-3mN/m; at high temperature (86-120 ℃) or high salt(s) ((R))>40000mg·L-1，Ca2+、Mg2+>2000mg·L-1) During oil reservoir, the effective stable period is long, the oil displacement effect is good, the current situation of oil field development can be obviously improved, and an effective solution is provided for further improving the recovery ratio of the high-temperature high-salt oil reservoir in ChinaThe method is described.
In the present invention, the sources of all raw materials are not particularly limited, and they may be commercially available.
The organic carboxylic acid monomer containing the acrylimide group is preferably shown as a formula (1), wherein m is preferably an integer of 1-4, namely m is 1, 2, 3 or 4.
The acrylamide-based monomer is preferably acrylamide and/or methacrylamide.
The N-alkyl substituted acrylamide sulfonic acid monomer is preferably shown as a formula (2), wherein R is preferably C6-C19 alkyl, more preferably C8-C19 alkyl, further preferably C10-C18 alkyl, and most preferably C12-C16 alkyl; in some embodiments provided herein, R is specifically a C12 or C16 alkyl group.
The vinyl aniline group-containing polyol monomer is preferably shown as a formula (3), n is preferably an integer of 1-5, and more preferably an integer of 1-4; in the examples provided by the present invention, n is specifically 1, 2, 3 or 4.
The mass ratio of the organic carboxylic acid monomer containing the acrylimide group, the acrylamide monomer, the N-alkyl substituted acrylamide sulfonic acid monomer and the polyalcohol monomer containing the vinylaniline group is preferably (13-30): (50-90): (5-19): (6-28), more preferably (15-28): (60-90): (5-18): (10-28), more preferably (18-28): (65-90): (8-18): (12-28), more preferably (18-26): (65-85): (9-15): (12-28), most preferably (18-25): (67-85): (9-15): (14-20); in the embodiment provided by the invention, the mass ratio of the organic carboxylic acid monomer containing an acrylimide group, the acrylamide monomer, the N-alkyl substituted acrylamide sulfonic acid monomer and the polyalcohol monomer containing a vinylaniline group is specifically 20: 67: 15: 14. 18: 75: 11: 16. 21: 78: 9: 17 or 25: 85: 12: 20.
in the present invention, the step S1) is preferably specifically: A) mixing a solubilizer water solution with an N-alkyl substituted acrylamide sulfonic acid monomer to obtain a solution A; mixing an organic carboxylic acid monomer containing an acrylimide group, an acrylamide monomer, a polyalcohol monomer containing a vinylaniline group and water to obtain a solution B; B) and adjusting the pH value of the solution B to 6-8, adding the solution A, a stabilizer, a chain transfer agent and a cosolvent, deoxidizing, adding an initiator, and carrying out polymerization reaction to obtain the rubber block. The solution A and the solution B are prepared in no sequence.
Mixing a solubilizer water solution with an N-alkyl substituted acrylamide sulfonic acid monomer to obtain a solution A; the aqueous solution of the solubilizer is preferably an aqueous solution of an alkyl sulfate surfactant, more preferably an aqueous solution of sodium dodecyl sulfate; the mass concentration of the solubilizer in the solubilizer water solution is preferably 1 to 5 percent, more preferably 1.5 to 3 percent, and still more preferably 1.5 to 2.5 percent; in the examples provided by the invention, the mass concentration of the solubilizer water solution is specifically 2.35%, 2.15%, 2% or 1.85%; the mass ratio of the solubilizer water solution to the N-alkyl substituted acrylamide sulfonic acid monomer is preferably (150-250): (5-20), more preferably (180-250): (5-15), more preferably (190-240): (9-15); in the embodiment provided by the invention, the mass ratio of the aqueous solution of the solubilizer to the N-alkyl substituted acrylamide sulfonic acid monomer is specifically 210: 15. 195: 11. 200: 9 or 240: 12.
mixing an organic carboxylic acid monomer containing an acrylimide group, an acrylamide monomer, a polyalcohol monomer containing a vinylaniline group and water to obtain a solution B; the water is preferably deionized water; the mass ratio of the acrylamide monomer to water is preferably (50-90): (200-1150), more preferably (60-90): (300-1000), and more preferably (65-90): (400-800), and more preferably (65-85): (400-740), most preferably (67-85): (400-740); in the embodiment provided by the invention, the mass ratio of the acrylamide monomer to water is specifically 67: 440. 75: 510. 78: 700 or 85: 740.
adjusting the pH value of the solution B to 6-8, preferably adjusting the pH value of the solution B by adopting alkali; the alkali is preferably sodium hydroxide and/or sodium carbonate; in the invention, the pH value of the solution B is preferably adjusted to 6.5-8, and more preferably 6.8-7.7; in the examples provided by the present invention, the pH of the solution B is specifically adjusted to 6.8, 7.7, 7.2 or 7.5.
Then adding the solution A, a stabilizer, a chain transfer agent and a cosolvent; the stabilizer is preferably disodium ethylene diamine tetraacetate; the chain transfer agent is preferably one or more of dodecyl mercaptan, isopropanol, sodium formate and sodium bisulfite; the cosolvent is preferably one or more of carbamide, sodium propenyl sulfonate and sodium methyl propenyl sulfonate; the mass ratio of the acrylamide monomer, the stabilizer, the chain transfer agent and the cosolvent is preferably (50-90): (0.01-1): (0.001-0.1): (0.01-1), more preferably (60-90): (0.03-0.5): (0.003-0.05): (0.03-0.6), and more preferably (65-90): (0.03-0.3): (0.003-0.03): (0.05-0.6), preferably (65-85): (0.05-0.1): (0.003-0.01): (0.1 to 0.4), most preferably (67 to 85): (0.07-0.08): 0.005: (0.2 to 0.23); in the embodiment provided by the invention, the mass ratio of the acrylamide monomer, the stabilizer, the chain transfer agent and the cosolvent is specifically 67: 0.07: 0.005: 0.2, 75: 0.07: 0.005: 0.2, 78: 0.08: 0.005: 0.23 or 85: 0.08: 0.005: 0.23.
preferably stirring and dissolving, deoxidizing, and adding an initiator; the oxygen removal treatment is preferably carried out by means of nitrogen; the oxygen removal treatment is preferably carried out at a temperature of 2-12 ℃, more preferably at a temperature of 5-10 ℃; the time of the oxygen removal treatment is preferably 20-30 min; the initiator is preferably a redox-azo water-soluble composite initiator, and more preferably a composite initiator of persulfate-sulfite and azobisisobutylamidine hydrochloride; the persulfate is preferably ammonium persulfate; the sulfite is preferably sodium formaldehyde sulfoxylate; the mass ratio of persulfate to sulfite to azodiisobutyl amidine hydrochloride in the initiator is preferably (0.05-1.2): (0.025-0.6): (0.08-2.3), more preferably (0.07-1.0): (0.04-0.4): (0.1-2.0), and more preferably (0.07-0.5): (0.04-0.2): (0.1 to 1.5), and more preferably (0.07 to 0.2): (0.04-0.1): (0.1 to 1), and most preferably 0.09: 0.05: 0.2; in the present invention, the initiator is preferably added in the form of an aqueous solution, that is, an aqueous redox solution and an aqueous azo initiator solution, respectively; the mass concentration of the oxidant and the mass concentration of the reducer in the redox aqueous solution are respectively and independently preferably 0.05-0.3%, more preferably 0.08-0.2%, and still more preferably 0.1%; the mass concentration of the azo initiator in the azo initiator aqueous solution is preferably 0.05-0.3%, more preferably 0.08-0.2%, and even more preferably 0.1%; in the invention, the mass ratio of the acrylamide monomer to the persulfate is preferably (50-90): (0.00005 to 0.0012); in the embodiment provided by the invention, the mass ratio of the acrylamide monomer to the persulfate is specifically 67: 0.00009, 75: 0.00009, 78: 0.00009 or 85: 0.00009.
after the initiator is added, preferably, oxygen removal treatment is continuously carried out, and then polymerization reaction is carried out to obtain a rubber block; the oxygen removal treatment is preferably carried out by means of nitrogen; the time of the oxygen removal treatment in the step is preferably 5-15 min, and more preferably 10 min; the polymerization reaction is preferably carried out under closed adiabatic conditions; the polymerization reaction is preferably carried out under oxygen-free conditions; the temperature at which the polymerization reaction starts is preferably 2 to 12 ℃, and more preferably 5 to 10 ℃; the time of the polymerization reaction is preferably 3 to 7 hours, more preferably 4 to 7 hours, and still more preferably 4.5 to 7 hours.
The invention adopts a post-hydrolysis process, preferably washes and granulates the rubber block, and hydrolyzes; the hydrolysis is preferably performed by using sodium hydroxide; the hydrolysis temperature is preferably 80-100 ℃, and more preferably 90 ℃; the hydrolysis time is preferably 1.5-3 h, and more preferably 2-2.5 h.
And after hydrolysis, preferably drying, crushing and sieving to obtain the polymer for oil extraction of the high-temperature and high-salinity oil reservoir.
The main chain of the polymer molecule provided by the invention is of a carbon chain structure, and the functional monomer is directly polymerized onto the main chain of the polyacrylamide, so that the molecular structure is stable. In the polymerization process in the presence of a chain transfer agent, imide groups in the organic carboxylic acid monomers have a certain inhibiting effect on imidization crosslinking of the product, and the solubility of the product is improved; in addition, the monomer has a strong molecular chelation effect on divalent ions, which is enhanced by the ortho-group effect of adjacent amide units. The N-alkyl substituted acrylamide sulfonic acid monomer is introduced, and the viscosity of the polymer can be improved by adjusting the length of an alkyl carbon chain; the distribution and length of the block of the monomer on the main chain of the copolymer are influenced by adjusting the dosage ratio of the monomer to the surfactant, and the association between molecules is further influenced; the combined action of the two components enables the copolymerization products to have certain strength and reversible association between molecules, effectively constructs a three-dimensional network structure and enhances the shear resistance of the polymer. The introduction of the vinyl aniline group-containing polyol monomer leads the repeat unit to have large space volume, enhanced steric hindrance effect and reduced probability of molecular long chain breakage due to the existence of rigid monomers such as phenyl and the like, thereby leading the polymer to keep stable performance for a long time at high temperature.
In addition, the strong hydrophilicity and the electrostatic repulsion action of carboxyl, alcoholic hydroxyl and sulfonic group in the molecular structure greatly increase the water solubility of the polymer and the hydrodynamic volume of a molecular chain, and show good tackifying property; wherein-SO3 -Has high charge density, can improve the salt resistance of the polymer, particularly does not generate precipitation with divalent cations, and inhibits-CONH to a certain extent2Thereby improving the stability of the product group. The chain transfer agent and the cosolvent have a synergistic effect, so that chain transfer of free radicals to tertiary carbon is avoided, the branching or crosslinking of the product is further controlled, meanwhile, direct hydrogen bond association among the product molecules is dispersed to a certain degree, and the dissolution and tackifying properties and the salt resistance of the product are improved.
The invention also provides application of the polymer for oil recovery of the high-temperature and high-salinity reservoir in the high-temperature reservoir and/or the high-salinity reservoir.
The temperature of the high-temperature oil reservoir is preferably 86-120 ℃; the mineralization degree of the high-salt oil reservoir is preferably more than 40000 mg.L-1，Ca2+、Mg2+Preferably greater than 2000 mg.L-1。
In order to further illustrate the invention, the following describes in detail a polymer for oil recovery of high temperature and high salinity reservoir, its preparation method and application with reference to the examples.
The reagents used in the following examples are all commercially available.
Characteristic viscosity number [ eta ] of polymer product for oil extraction of high-temperature high-salinity oil reservoir]And the relative molecular weight is measured and calculated according to the method 6.10 in SY/T5862-2008 'technical requirement for polymer for oil displacement'; by different treatments (high temperature 90 ℃ or high salt 100000 mg.L)-1Or 170s-1Lower shearing) to inspect the temperature, salt and shear resistance of the sample according to the condition of the apparent viscosity retention rate of the sample solution; the heat-resistant aging performance of the sample is inspected through a high-temperature aging experiment; in addition, the application of the sample in the binary composite flooding of the Russian certain oil field area is considered, and the change of the viscosity and the interfacial tension of the poly-epi binary composite system along with the high-temperature aging time is evaluated in detail.
Example 1
1.1 solubilizing 15 parts of an N-alkyl-substituted acrylamide sulfonic acid monomer (alkyl group having 12 carbon atoms) represented by the formula (2) with 210 parts of a 2.35% aqueous solution of sodium lauryl sulfate, and uniformly dispersing the solubilized monomer by stirring to obtain a solution A.
1.2 acrylamide 67 parts, acryloylimino-containing organic carboxylic acid monomer (m ═ 2)20 parts represented by formula (1), vinylanilino-containing polyol (n ═ 3) monomer 14 parts represented by formula (3), and deionized water 440 parts were sequentially added to a polymerization flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen-introducing tube, and stirred until completely dissolved, and the vessel was placed in ice water to obtain solution B.
1.3 adjusting the pH value of the solution B to 6.8 by using an aqueous solution of sodium hydroxide, adding the solution A obtained in the step 1.1, 0.07 part of disodium ethylene diamine tetraacetate, 0.005 part of sodium formate and 0.2 part of sodium methyl propenyl sulfonate into a polymerization bottle in sequence, and stirring until the solution is dissolved uniformly.
1.4 controlling the initial temperature of the system at 5 ℃, introducing nitrogen to remove oxygen for 20-30min, adding a redox-azo water-soluble composite initiator (0.09 part by weight of 0.1% ammonium persulfate aqueous solution, 0.05 part by weight of 0.1% sodium formaldehyde sulfoxylate aqueous solution and 0.2 part by weight of 0.1% azodiisobutyl amidine hydrochloride aqueous solution), and continuing introducing nitrogen to remove oxygen for 10 min.
1.5 reacting for 4.5h under the closed adiabatic condition to obtain the rubber block.
And 1.6 taking out the rubber block, washing and granulating, uniformly mixing the rubber block and sodium hydroxide by adopting a post-hydrolysis process, putting the mixture into a drying oven at 90 ℃ for hydrolysis for 2 hours, taking out, drying, crushing and sieving to obtain a polymer finished product for high-temperature and high-salinity reservoir oil extraction.
Example 2
2.1 solubilizing 11 parts of an N-alkyl-substituted acrylamide sulfonic acid monomer represented by the formula (2) (having 12 carbon atoms in the alkyl group) with 195 parts of a 2.15% aqueous solution of sodium lauryl sulfate, and uniformly dispersing the solubilized monomer by stirring to obtain a solution A.
2.2 acrylamide 75 parts, an acryloylimino-containing organic carboxylic acid monomer (m ═ 4) represented by formula (1), a vinylanilino-containing polyol (n ═ 2) monomer represented by formula (3), and deionized water 510 parts were sequentially added to a polymerization flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen-introducing tube, and stirred until completely dissolved, and the vessel was placed in ice water to obtain solution B.
2.3 adjusting the pH value of the solution B to 7.7 by using an aqueous solution of sodium hydroxide, adding the solution A obtained in the step 2.1, 0.07 part of disodium ethylenediamine tetraacetic acid, 0.005 part of sodium formate and 0.2 part of sodium methyl propenyl sulfonate into a polymerization bottle in sequence, and stirring until the solution is dissolved uniformly.
2.4 controlling the initial temperature of the system at 10 ℃, introducing nitrogen to remove oxygen for 20-30min, adding a redox-azo water-soluble composite initiator (0.09 part by weight of 0.1% ammonium persulfate aqueous solution, 0.05 part by weight of 0.1% sodium formaldehyde sulfoxylate aqueous solution and 0.2 part by weight of 0.1% azodiisobutyl amidine hydrochloride aqueous solution), and continuing introducing nitrogen to remove oxygen for 10 min.
2.5 reacting for 6h under the condition of closed heat insulation to obtain the rubber block.
And 2.6 taking out the rubber block, washing and granulating, adopting a post-hydrolysis process, uniformly mixing the rubber block and sodium hydroxide, putting the mixture into a drying oven at 90 ℃ for hydrolysis for 2.5 hours, taking out, drying, crushing and sieving to obtain a polymer finished product for high-temperature and high-salinity oil reservoir oil extraction.
Example 3
3.1 solubilization of 9 parts of N-alkyl-substituted acrylamide sulfonic acid monomer (alkyl carbon number 16) represented by formula (2) with 200 parts of 2% aqueous solution of sodium dodecyl sulfate, and stirring to disperse uniformly to obtain solution A.
3.2 acrylamide 78 parts, acrylimido-containing organic carboxylic acid monomer (m ═ 3) represented by formula (1), vinylanilino-containing polyol (n ═ 4) monomer represented by formula (3), and deionized water 700 parts were sequentially added to a polymerization flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen-introducing tube, and stirred until completely dissolved, and the vessel was placed in ice water to obtain solution B.
3.3 adjusting the pH value of the solution B to 7.2 by using an aqueous solution of sodium hydroxide, adding the solution A obtained in 3.1, 0.08 part of disodium ethylenediamine tetraacetic acid, 0.005 part of sodium formate and 0.23 part of sodium methyl propenyl sulfonate into a polymerization bottle in sequence, and stirring until the solution is dissolved uniformly.
3.4 controlling the initial temperature of the system at 6 ℃, introducing nitrogen to remove oxygen for 20-30min, adding a redox-azo water-soluble composite initiator (0.09 part by weight of 0.1% ammonium persulfate aqueous solution, 0.05 part by weight of 0.1% sodium formaldehyde sulfoxylate aqueous solution and 0.2 part by weight of 0.1% azodiisobutyl amidine hydrochloride aqueous solution), and continuing introducing nitrogen to remove oxygen for 10 min.
3.5 reacting for 7h under the closed adiabatic condition to obtain the rubber block.
3.6 taking out the rubber block, washing and granulating, adopting a post-hydrolysis process, uniformly mixing the rubber block and sodium hydroxide, putting the mixture into a drying oven at 90 ℃ for hydrolysis for 2 hours, taking out, drying, crushing and sieving to obtain a polymer finished product for oil extraction of the high-temperature and high-salinity oil reservoir.
Example 4
4.1 solubilizing 12 parts of an N-alkyl-substituted acrylamide sulfonic acid monomer (alkyl carbon number 16) represented by the formula (2) with 240 parts of a 1.85% aqueous solution of sodium dodecyl sulfate, and uniformly dispersing the solubilized N-alkyl-substituted acrylamide sulfonic acid monomer by stirring to obtain a solution A;
4.2 acrylamide 85 parts, an acryloylimino-containing organic carboxylic acid monomer (m ═ 1) represented by formula (1) 25 parts, a vinylanilino-containing polyol (n ═ 1) monomer represented by formula (3) 20 parts, and deionized water 740 parts were sequentially added to a polymerization flask equipped with a stirrer, a thermometer, a condenser, and a nitrogen-introducing tube, and stirred until completely dissolved, and the vessel was placed in ice water to obtain solution B.
4.3 adjusting the pH value of the solution B to 7.5 by using an aqueous solution of sodium hydroxide, adding the solution A, 0.08 part of disodium ethylenediamine tetraacetic acid, 0.005 part of sodium formate and 0.23 part of sodium methyl propenyl sulfonate into a polymerization bottle in sequence, and stirring until the solution is dissolved uniformly.
4.4 controlling the initial temperature of the system at 8 ℃, introducing nitrogen to remove oxygen for 20-30min, adding a redox-azo water-soluble composite initiator (0.09 part by weight of 0.1 percent aqueous ammonium persulfate solution, 0.05 part by weight of 0.1 percent aqueous sodium formaldehyde sulfoxylate solution and 0.2 part by weight of 0.1 percent aqueous azodiisobutyl amidine hydrochloride solution), and continuing introducing nitrogen to remove oxygen for 10 min.
4.5 reaction for 5.5h under the closed adiabatic condition to obtain the rubber block.
4.6 taking out the rubber block, washing and granulating, adopting a post-hydrolysis process, uniformly mixing the rubber block and sodium hydroxide, putting the mixture into a drying oven at 90 ℃ for hydrolysis for 2.5h, taking out, drying, crushing and sieving to obtain the polymer finished product for oil extraction of the high-temperature and high-salinity oil reservoir.
The intrinsic viscosity and the relative molecular weight of the polymers for high-temperature and high-salinity reservoir oil recovery obtained in examples 1 to 4 were measured, and the results are shown in table 1.
Table 1 examples 1-4 intrinsic viscosity and relative molecular weight of polymers for oil recovery in high temperature and high salinity reservoirs
Examples
Intrinsic viscosity (mL/g)
Relative molecular weight
1
1717.4
8.86×106
2
2174.8
1.19×107
3
2594.5
1.48×107
4
3039.5
1.81×107
The concentration of the mother liquor of the polymer sample for oil extraction of the high-temperature and high-salinity reservoir prepared in the embodiments 1 to 4 is 5000 mg.L prepared by using clean water-1The degree of mineralization is 100000 mg.L-1Diluting the sample mother liquor to 2000 mg.L with saline-1Stirring for 5 hours at room temperature, and inspecting the salt resistance; ② diluting the sample mother liquor to 2000 mg.L with clear water-1Slowly stirring for 5 hours at 90 ℃, and inspecting the temperature resistance; ③ diluting the mother solution of the sample to 2000 mg.L with clear water-1Using an electric six-speed viscometer at 170s-1The shear rate (2) was continuously sheared for 60min, and the shear resistance was examined. The relevant data are shown in tables 2, 3 and 4, and the apparent viscosity of the solution is measured at 60 ℃.
Table 2 results of salt tolerance test
TABLE 3 test results of temperature resistance
TABLE 4 test results of shear resistance
As can be seen from tables 2, 3 and 4, the apparent viscosity retention rates of the solutions prepared from the polymers for oil recovery in the high-temperature high-salt oil reservoir provided by the embodiments are all above 70% after the solutions are subjected to temperature-resistant, salt-resistant and shear-resistant treatment, which indicates that the products provided by the embodiments of the present invention have wide application prospects due to their good temperature-resistant, salt-resistant and shear-resistant properties when applied to oil recovery in the high-temperature high-salt oil reservoir.
Slowly adding the polymer sample for oil extraction of the high-temperature and high-salinity reservoir prepared in the embodiment 1 to 4 into the polymer sample with the mineralization degree of 100000 mg.L-1The brine of (4) was prepared in a beaker at a concentration of 2000 mg.L-1The polymer aqueous solution is vacuumized to remove oxygen, sealed in an ampoule bottle, placed in an oven at 86 ℃ for aging for 0d, 3d, 7d, 15d, 30d, 45d, 60d and 90d in sequence, taken out, and subjected to aging at 86 ℃ for 7.34s-1The viscosity was measured at shear rate while the traditional 2500 million molecular weight polyacrylamide HPAM was selected as the control and the results are shown in Table 5.
TABLE 5 ageing resistance test results
As can be seen from Table 5, the apparent viscosity of the polymer for oil recovery in the high-temperature and high-salinity reservoir in the embodiment of the invention is always higher than that of the conventional HPAM, which shows that the polymer for oil recovery in the high-temperature and high-salinity reservoir provided by the invention has extremely excellent aging resistance, and the mineralization degree is 100000 mg.L at 86 DEG C-1The viscosity retention rate is still higher after aging for 90 days under the anaerobic condition, and is basically maintained to be about 90 percent or even higher.
Application example: application of the invention in Russian certain oil field block binary combination flooding
The formation simulated water (ion composition is shown in table 6) of a certain Russian oilfield block is prepared to have the concentration of 5000 mg.L-1Diluting the polymer mother liquor obtained in the embodiment 1 or 2 to a specified concentration, compounding the polymer mother liquor with a corresponding surfactant to form a binary oil displacement system (0.2 percent of the surfactant in the embodiment 1 or 2+0.2 percent), vacuumizing and deoxidizing, then packaging the polymer mother liquor in an ampoule bottle, putting the ampoule bottle in an oven at 86 ℃ for aging for 0d, 3d, 7d, 15d, 30d, 45d, 60d and 90d in sequence, taking out the polymer mother liquor, and taking out the polymer mother liquor at 86 ℃ and 7.34s-1The viscosity was measured at shear rate, and the interfacial tension of the system was measured at 86 ℃ and 5000rpm using a TX500C interfacial tension apparatus and Russian model oil, the results of which are shown in tables 7 and 8.
TABLE 6 simulated water ion composition of formation
Ion(s)
Na+
Ca2+
Mg2+
HCO3-
Cl-
TDS
Content/(mg. L)-1)
6800
800
400
1000
11000
20000
TABLE 7 thermal stability and ultra-low interfacial tension stability of Polyepi binary composite systems (0.2% example 1+ 0.2% surfactant)
TABLE 8 thermal stability and ultra-low interfacial tension stability of Polyepi binary composite systems (0.2% example 2+ 0.2% surfactant)
As can be seen from tables 7 and 8, the polymer for high-temperature and high-salt reservoir oil recovery provided in example 1 or 2 is compounded with the corresponding surfactant in the russian oilfield block to form a polymer-surfactant binary composite system, which has excellent temperature resistance and a viscosity retention rate of more than 90% after 90 days; the initial interfacial tension can be ultra-low, the two have high-efficiency synergistic effect, and can still be kept at 10 ℃ after 90 days-3The magnitude of mN/m, and the oil washing effect is obvious.
