Enhanced hydrocarbon recovery method using a crystalline polymer of 2-acrylamido-2-methylpropanesulfonate sodium salt

Abstract

Enhanced hydrocarbon recovery method comprising the following steps: a) Prepare an injection fluid containing at least one water-soluble polymer obtained from ATBS using water or brine, where ATBS, before polymerization, has 2θ angles of 11.7°, 12.2°, 13.2°, 13.5°, 15.6°, 16.8°, 17.8°, 18.5°, 19.1°, 20.6°, 21.4°, 23.3°, 25.1°, 25.8°, 26.9°, 29.1°, 29. The crystalline form of ATBS sodium salt having an X-ray powder diffraction pattern with peaks at 5°, 31.0°, 33.0°, 33.6°, 34.4°, 35.2°, 35.9°, 37.1°, 38.4°, 39.6°, 41.1°, 42.9°, 45.1°, 46.0°, 47.2°, and 47.6°; b) injecting an injection fluid into a subsurface layer; c) sweeping the subsurface layer using the injection fluid; d) recovering an aqueous hydrocarbon mixture.

Description

[Technical Field]

[0001] The present invention relates to an enhanced recovery method for hydrocarbons (oils and / or gases) using a water-soluble polymer obtained from the crystalline form of sodium 2-acrylamido-2-methylpropanesulfonate. [Background technology]

[0002] Most oil fields currently under development have matured, and their production is either already declining or about to begin declining soon. The recovery rate of these fields is currently on the order of 15% to 35% of the initial oil volume. Therefore, they always possess considerable production potential.

[0003] Generally, the recovery of crude oil contained in mineral deposits is carried out in several stages. Production primarily relies on the natural energy of fluids and rocks that reduce pressure themselves. At the end of this depletion phase, the amount of oil recovered from the surface averages approximately 5% to 15% of the initial reserves. Therefore, in the second stage, it is necessary to employ technologies that increase recovery by maintaining ground pressure.

[0004] The most frequently performed method involves injecting water into the deposit through a dedicated injection well. This method is called secondary recovery. This second phase ends when the water / oil ratio is too high, i.e., when there is too much water in the mixture produced by the production well. Thus, this secondary recovery can yield an additional recovery rate of the order of 10% to 20%.

[0005] Other techniques that can be used are known as enhanced oil recovery (EOR). Their purpose is to recover an additional 10% to 35% of the initial amount of oil. Various thermal and non-thermal techniques for enhancing the recovery of residual oil are known as enhanced oil recovery, and these include, for example, so-called electrical, miscible, steam, or even chemical techniques (see “Oil & Gas Science and Technology” - IFP Journal, vol 63 (2008) No. 1, pp 9-19).

[0006] The term "petroleum (oil)" should be understood to mean any type of petroleum, namely light oil, heavy oil, or even bituminous oil. Petroleum is typically the result of the natural transformation of organic matter and consists of a mixture of hydrocarbons. In the description of the prior art or the present invention, the terms "petroleum" and "petroleum (oil)" are used to refer to the same substance, except when describing the composition of an emulsion or dispersion.

[0007] The rate of water infiltration scavenging is generally improved by the addition of water-soluble polymers. The expected and demonstrated benefits of using polymers through "thickening" of infiltration water are improved scavenging and reduced viscosity differences between fluids to adjust mobility ratios in oil fields, with the aim of rapidly and efficiently recovering hydrocarbons. These polymers increase the viscosity of water.

[0008] Synthetic water-soluble polymers, particularly 2-acrylamido-2-methylpropanesulfonic acid polymers (ATBS), are highly advantageous polymers for increasing the viscosity of aqueous solutions and are known to those skilled in the art for use in enhanced recovery. In fact, ATBS polymers are known to be resistant to divalent salts and high temperatures.

[0009] The polymers used must not only increase the viscosity of water but also possess good filterability. Polymers with poor filterability tend to clog the layer, delaying or even inhibiting the production of hydrocarbons (oils and / or gases). However, filterability decreases as the molecular weight of the polymer increases. Therefore, there is a delicate balance between molecular weight and filterability.

[0010] Polymers added to injection water generally have long residence times in the deposit between the injection well and the production well, ranging from several months to several years. During this period, the polymer may undergo thermal decomposition, increasing the hydrolysis rate through conversion from acrylamide or ATBS units to acrylates, or chemical decomposition, leading to chain breakage (reduction in molecular weight) due to radical attack. In either case, these mechanisms generally result in a decrease in viscosity, thus leading to a loss of efficiency in sweeping subsurface layers with the injected aqueous polymer solution. Therefore, there is a practical interest in developing polymers that are more resistant to these processes involved in any hydrocarbon enhanced recovery project (oil and / or gas). [Overview of the project]

[0011] ●Disclosure of the Invention The applicant has discovered and developed an enhanced recovery method for hydrocarbons (oils and / or gases) using a water-soluble polymer containing a crystalline form of 2-acrylamido-2-methylpropanesulfonate sodium salt (ATBS.Na) as a monomer, wherein the polymer has improved properties, particularly with respect to filterability and chemical and thermal stability.

[0012] The improved performance of injection fluids containing polymers obtained from crystalline ATBS.Na helps reduce the amount of product required, thereby reducing total water consumption and emissions of greenhouse gases such as CO2.

[0013] More specifically, the present invention relates to an enhanced recovery method for hydrocarbons (oils and / or gases) comprising the following steps: a) Prepare an injection fluid containing at least one water-soluble polymer of 2-acrylamido-2-methylpropanesulfonic acid (ATBS) using water or brine; Here, the ATBS is a crystalline form of sodium ATBS salt having an X-ray powder diffraction pattern before polymerization that includes a group of peaks at 11.7°, 12.2°, 13.2°, 13.5°, 15.6°, 16.8°, 17.8°, 18.5°, 19.1°, 20.6°, 21.4°, 23.3°, 25.1°, 25.8°, 26.9°, 29.1°, 29.5°, 31.0°, 33.0°, 33.6°, 34.4°, 35.2°, 35.9°, 37.1°, 38.4°, 39.6°, 41.1°, 42.9°, 45.1°, 46.0°, 47.2°, and 47.6° at a 2θ angle; b) Injecting the aforementioned injection fluid into the subsurface layer; c) Using the aforementioned injection fluid to sweep the subsurface layer; d) Recover the aqueous hydrocarbon mixture (a mixture containing water and hydrocarbons).

[0014] Remarkably, the use of at least one water-soluble polymer obtained from the crystalline form of ATBS sodium salt enables effective treatment of subsurface layers. In fact, the use of ATBS sodium salt in crystalline form in the preparation of water-soluble polymers imparts specific properties to the polymer, thereby improving hydrocarbon recovery. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 shows the proton NMR spectrum of the ATBS needle crystal obtained in Example 1. [Figure 2] Figure 2 shows the proton NMR spectrum of the ATBS.Na crystal obtained in Example 2a. [Figure 3] Figure 3 shows the X-ray diffraction pattern of the ATBS crystal obtained in Example 1. [Figure 4] Figure 4 shows the X-ray diffraction pattern of the ATBS.Na crystal obtained in Example 2a. [Figure 5]Figure 5 shows the Fourier transform infrared spectrum of the ATBS crystal obtained in Example 1. [Figure 6] Figure 6 shows the Fourier transform infrared spectrum of the ATBS.Na crystal obtained in Example 2a. [Figure 7] Figure 7 shows the thermogram of the ATBS crystal obtained in Example 1. [Figure 8] Figure 8 shows the thermogram of the ATBS.Na crystal obtained in Example 2a. [Figure 9] Figure 9 shows the effect of the ATBS type on the viscosity reduction of solutions of polymers P3-ANa2a (the present invention) and P'3-AH (the acidic form of ATBS) in contact with various amounts of iron(II) impurities. [Figure 10] Figure 10 shows the effect of the ATBS type on viscosity reduction when polymers P6-ANa2a (the present invention) and P'6-AH (the acidic form of ATBS) are aged at 90°C. [Figure 11] Figure 11 shows the effect of the ATBS type on the viscosity reduction of solutions of homopolymers P6-ANa2a (the present invention) and P'6-AH (the acidic form of ATBS) in contact with various amounts of iron(II) impurities. [Figure 12] Figure 12 shows an optical microscope image of the ATBS crystal obtained in Example 1. [Figure 13] Figure 13 shows an optical microscope image of the ATBS.Na crystal obtained in Example 2a. [Figure 14] Figure 14 shows an optical microscope image of the ATBS.Na crystal obtained in Example 2b. [Figure 15] Figure 15 shows an optical microscope image of the ATBS.Na crystal obtained in Example 2c. [Figure 16] Figure 16 shows a photograph of the ATBS.Na product obtained in solution according to Comparative Example 2a. [Figure 17] Figure 17 shows an optical microscope image of the ATBS.Na crystal obtained in Comparative Example 2c. [Figure 18] Figure 18 shows an optical microscope image of the ATBS.Na crystal obtained in Comparative Example 2d. [Figure 19] Figure 19 shows an optical microscope image of the ATBS.Na crystal obtained in Comparative Example 2e. [Modes for carrying out the invention]

[0016] ●Description of the invention The term "polymer" should be understood to mean a homopolymer or copolymer. The term "copolymer" should be understood to mean a polymer obtained from at least two different monomers. Therefore, it may be a copolymer of at least two monomers selected from hydrophilic anionic monomers, hydrophilic cationic monomers, hydrophilic nonionic monomers, hydrophilic zwitterionic monomers, hydrophobic monomers, and mixtures thereof.

[0017] The term "hydrophilic monomer" refers to an octanol-water partition coefficient K of 1 or less. ow It should be understood that this means a monomer having a partition coefficient K ow This is determined at 25°C in a 1:1 volume octanol-water mixture with a pH of 6-8.

[0018] The terms "crystal" or "crystalline form" refer to solid materials in which their constituent elements (atoms, molecules, or ions, etc.) are arranged in a highly ordered microstructure, forming a crystalline lattice that extends in all directions. This does not include amorphous solids.

[0019] The term "hydrophobic monomer" refers to an octanol-water partition coefficient greater than 1 K ow It should be understood that this means a monomer having a partition coefficient K ow This is determined at 25°C in a 1:1 volume octanol-water mixture with a pH of 6-8.

[0020] Octanol-water partition coefficient K ow This represents the ratio (g / L) of monomer concentrations between the octanol phase and the aqueous phase. The partition coefficient is defined as follows:

number

[0021] According to the definition, a water-soluble polymer is dissolved in water at 25°C while stirring, in a volume of 50 g / L. -1 This polymer, when dissolved at a certain concentration, yields an aqueous solution free of insoluble particles.

[0022] "X and / or Y" should be understood to mean "X", "Y", or "X and Y".

[0023] The present invention also includes all possible combinations of the various embodiments disclosed, whether they are preferred embodiments or given as examples. Furthermore, where numerical ranges are indicated, boundary values ​​are included within those ranges. The disclosure also includes all combinations between the boundary values ​​of these numerical ranges. For example, the numerical range "1 to 20, preferably 5 to 15" implies the disclosure of the range "1 to 5", the range "1 to 15", the range "5 to 20", and the range "15 to 20", as well as the values ​​1, 5, 15, and 20.

[0024] ● Crystal form of ATBS sodium salt The crystalline form of ATBS sodium salt has an X-ray powder diffraction pattern that includes a group of peaks located at 2θ angles of 11.7°, 12.2°, 13.2°, 13.5°, 15.6°, 16.8°, 17.8°, 18.5°, 19.1°, 20.6°, 21.4°, 23.3°, 25.1°, 25.8°, 26.9°, 29.1°, 29.5°, 31.0°, 33.0°, 33.6°, 34.4°, 35.2°, 35.9°, 37.1°, 38.4°, 39.6°, 41.1°, 42.9°, 45.1°, 46.0°, 47.2°, and 47.6°. The uncertainty of these peaks is generally on the order of + / -0.1°.

[0025] X-ray crystallography, radiation crystallography, or X-ray diffraction is an analytical technique used to study the structure of crystals at the atomic scale. It is based on the physical phenomenon of X-ray diffraction. A diffraction apparatus with a copper source can be used.

[0026] Powders formed from a specific crystal phase always exhibit diffraction peaks in the same direction. Therefore, this diffraction pattern forms the true signature of the crystal phase. Thus, it is possible to determine the nature of each crystal phase within a mixture or a pure substance.

[0027] This signature is specific to each crystalline organic or inorganic compound and is in the form of a list of peaks located at the angle of 2θ (two theta).

[0028] This technique is used to characterize substances, particularly to characterize the various crystal forms that can exist for the same chemical molecule.

[0029] The crystal form of the ATBS sodium salt has a Fourier transform infrared spectrum containing a group of peaks at 3576 cm -1 , 3485 cm -1 , 3310 cm -1 , 3079 cm -1 , 2975 cm -1 , 1658 cm -1 , 1629 cm -1 , 1543 cm -1 , 1403 cm -1 , 1321 cm -1 , 1301 cm -1 , 1205 cm -1 , 1187 cm -1 , 1163 cm -1 , 1046 cm -1 , 980 cm -1 , 629 cm -1 . The uncertainty of these peaks is generally on the order of 8 cm -1 .

[0030] Infrared measurements are performed by Fourier transform, for example, with a Perkin Elmer Spectrum 100 spectrometer equipped with a single reflection ATR polarization accessory, and are performed by Fourier transform with an accuracy of 8 cm -1 .

[0031] Fourier transform infrared spectroscopy is the analysis of vibrations emitted, absorbed, or scattered by molecules. This technique is sensitive to so-called short-range interactions (the influence of a unit mesh on bonding). In most cases, the Fourier transform infrared spectra of different crystal systems are significantly different. Therefore, the Fourier transform infrared spectrum reflects the details of the crystalline structure of a compound.

[0032] Generally, unless otherwise specified, X-ray diffraction patterns and infrared spectra are obtained at 20°C and a pressure of 1 absolute atmosphere (101,325 Pa).

[0033] The crystalline form of ATBS sodium salt has a minimum ignition energy greater than 500 mJ, preferably greater than 1000 mJ (1 mJ = 10⁻¹⁰ mJ). -3 Jules).

[0034] Minimum ignition energy represents the minimum energy that must be supplied to a substance (compound) to ignite it. This energy can be electrical or thermal. Minimum ignition energy is essential information when considering the risk of explosion during substance handling (transport, storage, reaction, molding, etc.).

[0035] The minimum ignition energy depends on the properties of the powder (composition) and its polymer structure (particle size, crystal form, specific surface area). For solids, this energy is the minimum energy of an electrical spark that is likely to ignite a dust cloud. The higher the minimum ignition energy, the lower the risk the solid poses when it is used, handled, or stored.

[0036] The minimum ignition energy is measured according to the standard NF EN 13821. The crystalline form of ATBS sodium salt exhibits four thermal phenomena at 49.8°C, 144.8°C, 169.8°C, and 254.3°C, as determined by differential scanning calorimetry. The uncertainty regarding the observation of these phenomena is generally on the order of 10°C, and preferably less than 5°C.

[0037] Thermal phenomena are measured by differential scanning calorimetry (DSC). This technique involves measuring the thermal fluctuations associated with the thermal denaturation of a compound when heated at a constant rate, for example, with a heating gradient of 10°C / min.

[0038] ● Method for producing the crystalline form of ATBS sodium salt A method for producing the crystalline form of ATBS sodium salt includes at least the following sequential steps: 1) To form an aqueous solution or aqueous suspension SA2, mix ATBS with an aqueous solution SA1 and at least one sodium salt base, preferably for at least 1 minute; 2) Distill the aqueous solution or aqueous suspension SA2 at a pressure of 700 mbar or less in order to form suspension S1; 3) Separating the suspension S1 into solid and liquid components, and isolating the crystals of the suspension S1 obtained in the form of composition C1 at the end of step 2). The resulting crystal is the aforementioned crystalline form of ATBS sodium salt.

[0039] The "sodium salt base" in step 1) should be understood to mean at least one inorganic sodium salt Brønsted base, such as sodium hydroxide, sodium carbonate, sodium bicarbonate, or a mixture thereof.

[0040] The temperature and mixing time in step 1) can vary, in particular, as a function of the concentration of ATBS. Those skilled in the art know how to adapt the temperature variations and mixing time to optimize crystal formation.

[0041] The method for producing the crystalline form of ATBS.Na can be applied to any form of ATBS, such as a needle-like form or a hydrated form. The above manufacturing method may be carried out on ATBS of any purity.

[0042] Therefore, the method may be carried out downstream of any type of ATBS manufacturing method. The method may also be carried out on any form of ATBS already obtained, i.e., amorphous or crystalline.

[0043] ●Step 1 of the method for producing the above crystalline form of ATBS.Na): ATBS is produced by the manufacturing method described above (acrylonitrile, fuming sulfuric acid, and isobutylene). ATBS may be in the form of a fine powder, or it may be molded in a controlled manner by methods such as compression, granulation, or extrusion.

[0044] ATBS may be added to aqueous solution SA1 before, after, or in parallel with the sodium salt base, and preferably in parallel with the sodium salt base. Preferably, the aqueous solution is water.

[0045] The sodium salt base may be added as an aqueous solution SA1. In this case, the aqueous solution of the sodium base may be partially or entirely aqueous solution SA1. Advantageously, the concentration of ATBS sodium salt in the aqueous solution or aqueous suspension SA2 is 1% by weight to the saturation concentration, preferably 10% by weight to the saturation concentration, more preferably 20% by weight to the saturation concentration, more preferably 30% by weight to the saturation concentration, more preferably 40% by weight to the saturation concentration, and even more preferably 50% by weight to the saturation concentration, based on the weight of the aqueous solution or aqueous suspension SA2.

[0046] ATBS and sodium base may be added all at once or in several stages. It is preferable that they be added all at once. When adding them in several stages, ATBS and sodium salt bases are added in fractions.

[0047] When ATBS and sodium salt base are added in partial amounts, there is no limit to the number of parts, but it is advantageous to have at least two parts, preferably at least three parts.

[0048] There are no restrictions on the order in which ATBS and sodium salt base are added. They may be added simultaneously (i.e., in parallel), sequentially (ATBS first, then sodium salt base, or vice versa), or alternately (first portion of ATBS, then first portion of sodium salt base, then second portion of ATBS, then second portion of sodium salt base, and so on), but they are preferably added simultaneously.

[0049] When added sequentially or alternately, the addition of the second compound (which may be ATBS or a sodium salt base) can begin before the addition of the first compound is complete.

[0050] The first portion F1 of ATBS advantageously accounts for 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and even more preferably 20 mol% or more of the total ATBS present in the aqueous solution or aqueous suspension SA2.

[0051] The second portion F2 of ATBS is advantageously comprised of 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and even more preferably 20 mol% or more, of the total ATBS present in the aqueous solution or aqueous suspension SA2.

[0052] The third portion F3 of ATBS is advantageously comprised of 1 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and even more preferably 20 mol% or more, of the total ATBS present in the aqueous solution or aqueous suspension SA2.

[0053] In one particular embodiment, the method is carried out continuously, in which case ATBS and sodium salt base are added continuously. The amount of ATBS in the aqueous solution or aqueous suspension SA2 is advantageously 10 to 90% by weight, preferably 20 to 85% by weight, and more preferably 30 to 80% by weight, relative to the total weight of the aqueous solution or aqueous suspension SA2.

[0054] The mixing in step 1) (ATBS + sodium salt base) is preferably carried out at a temperature of 0 to 90°C, preferably 5 to 60°C, more preferably 10 to 40°C, to obtain an aqueous solution or aqueous suspension SA2.

[0055] In a particular embodiment, the aqueous solution or aqueous suspension SA2 may contain one or more organic solvents.

[0056] In some embodiments, the aqueous solution SA1 may contain one or more organic solvents. The amount of organic solvent may vary as a function of temperature and the amount of ATBS or sodium salt base. This amount is not limited as long as it does not prevent the acquisition of the crystalline form of ATBS sodium salt base. Those skilled in the art will understand how to determine this limit, and this is routine work. Generally, aqueous solutions or aqueous suspensions SA2 contain more water (by volume) than organic solvent.

[0057] One or more organic solvents are advantageously selected from the following compounds: • Organic acids, preferably carboxylic acids containing 1 to 8 carbon atoms; • Amides, which preferably contain 1 to 8 carbon atoms; Alcohols, which preferably contain 1 to 8 carbon atoms; Ketones, which favorably contain 3 to 8 carbon atoms; Ethers, which preferably contain 2 to 8 carbon atoms; • Esters, which preferably contain 2 to 8 carbon atoms; Alkanes, which preferably contain 4 to 8 carbon atoms, and more preferably 5 to 6 carbon atoms; • Halogenated hydrocarbon compounds, which preferably contain 1 to 8 carbon atoms; Nitriles, which preferably contain 1 to 8 carbon atoms; or • A mixture of those.

[0058] When using an organic solvent in this invention, the temperature can be adjusted so that the mixture of solvent and water remains in a liquid state. These compounds may be linear or branched. They may be saturated or contain unsaturated bonds. Unsaturated bonds may be double or triple bonds. [ka] It corresponds to this.

[0059] The organic solvent is preferably selected from acrylonitrile, isopropanol, acrylic acid, acetic acid, or a mixture thereof. The organic solvent is preferably acrylonitrile. The organic solvent is generally liquid at the temperature at which steps 2) and 3) are performed. Furthermore, the organic solvent is advantageously partially miscible with water, and preferably completely miscible with water.

[0060] Organic solvents may be used, if necessary, to solubilize any impurities or by-products present with the ATBS used to form the aqueous solution or aqueous suspension SA2. However, the ATBS does not necessarily have to be soluble in the solvent.

[0061] In one preferred embodiment of the present invention, the aqueous solution or aqueous suspension SA2 does not contain an organic solvent. In one preferred embodiment of the present invention, the aqueous solution SA1 does not contain an organic solvent.

[0062] The allowable time for mixing aqueous solution SA1 and ATBS is advantageously 1 minute or more, preferably 1 to 600 minutes, more preferably 5 to 400 minutes, and even more preferably 10 to 240 minutes.

[0063] The compounds in step 1) can be mixed using a variety of techniques. Examples include, but are not limited to, reactors with agitators, loop reactors, static mixers, microreactors, piston reactors, agitated filter dryers (e.g., agitated filter dryers from Nutsche), paddle mixers, twin-cone mixers, plow shear mixers, and disc mixers.

[0064] The pH in step 1) is advantageously controlled to be 6-14, preferably 8-14, more preferably 10-14, even more preferably 12-14, and even more preferably 13-14.

[0065] The amount of ATBS.Na in the aqueous solution SA2 or aqueous suspension SA2 is advantageously 10 to 90% by weight, preferably 20 to 90% by weight, preferably 30 to 90% by weight, preferably 50 to 90% by weight, preferably 20 to 85% by weight, and more preferably 30 to 80% by weight, relative to the total weight of the aqueous solution or aqueous suspension SA2.

[0066] ●Step 2 of the method for producing the crystalline form of ATBS sodium salt): The distillation of aqueous solutions or aqueous suspensions of SA2 is carried out at a pressure of 700 mbar or less. This is generally done in a vacuum distillation apparatus, which is typically an evaporator. Therefore, this distillation is also referred to as "vacuum distillation" herein.

[0067] When an aqueous solution or aqueous suspension SA2 is distilled, typically by passing it through an evaporator, crystals of ATBS sodium salt begin to form. These ATBS sodium salt particles coexist in the aqueous solution or aqueous suspension SA2.

[0068] The aqueous solution or aqueous suspension SA2 can be distilled using an evaporator. This may be a drip evaporator, a vacuum evaporator, a scraper-type thin-film evaporator, a short-pass evaporator, a forced-circulation evaporator, a spiral-tube evaporator, or a flash evaporator. It may also be a continuous-stirring reactor. Preferably, the distillation is carried out in a scraper-type thin-film evaporator, a short-pass evaporator, or a forced-circulation evaporator. More preferably, the distillation is carried out in a scraper-type thin-film evaporator.

[0069] Generally, an evaporator is a device that includes an inlet for the solution to be processed (aqueous solution or aqueous suspension SA2), an outlet for discharging the distilled solvent (water and organic solvent), and an outlet for discharging the suspension S1.

[0070] The residence time of the aqueous solution or aqueous suspension SA2 (preferably under vacuum) in the distillation apparatus, preferably an evaporator, in other words, the distillation time at a pressure of 700 mbar or less, is preferably 1 second to 600 seconds, preferably 3 seconds to 300 seconds, and more preferably 30 seconds to 100 seconds. The residence time corresponds to the time required to carry out step 2), i.e., the time required to prepare suspension S1 by distillation of the aqueous solution or aqueous suspension SA2. In other words, when using an evaporator, it is the residence time of ATBS (and / or the crystalline form of its sodium salt) between the inlet and outlet of the apparatus. This residence time depends on the amount of water (and organic solvent, if any), ATBS.Na, and sodium salt base present in the aqueous solution or aqueous suspension SA2. Those skilled in the art will understand how to adapt the residence time to obtain the crystalline form of ATBS.Na depending on the amount of the components of the aqueous solution or aqueous suspension SA2.

[0071] Distillation can be carried out in a vertical evaporator or a horizontal evaporator. Preferably, distillation is carried out in a vertical evaporator.

[0072] The aqueous solution or aqueous suspension SA2 can be circulated in a parallel or countercurrent flow relative to the vapor produced by evaporation. Preferably, the aqueous solution or aqueous suspension SA2 is circulated in a countercurrent flow relative to the vapor within the distillation apparatus. In other words, the aqueous solution or aqueous suspension SA2 is introduced into the distillation apparatus, preferably into an evaporator, in a parallel or countercurrent flow relative to the distilled solvent.

[0073] The aqueous solution or aqueous suspension SA2 may be circulated in series through one or more evaporators before obtaining the suspension S1. Preferably, the aqueous solution or aqueous suspension SA2 is circulated through a single evaporator.

[0074] The pressure during distillation is preferably between 1 and 700 mbar (1 mbar = 100 Pa). Preferably, the pressure during distillation is less than 700 mbar, more preferably less than 600 mbar, more preferably less than 500 mbar, more preferably less than 400 mbar, more preferably less than 300 mbar, more preferably less than 200 mbar, more preferably less than 100 mbar, and even more preferably less than 50 mbar, where preferably more than 1 mbar. Absolute pressure corresponds to pressure relative to zero pressure (vacuum).

[0075] Generally, the pressure during distillation is preferably 10-700 mbar, preferably 20-700 mbar, preferably 40-700 mbar, more preferably 50-600 mbar, more preferably 50-500 mbar, more preferably 50-400 mbar, more preferably 50-300 mbar, more preferably 100-700 mbar, more preferably 200-700 mbar, more preferably 500-700 mbar, and more preferably 40-100 mbar.

[0076] In a particular embodiment, step 2) includes step 2') (optional) to help evaporate the solvent. Step 2') consists of raising the temperature of the aqueous solution or aqueous suspension SA2, in other words, the distillation by step 2') is carried out under heating.

[0077] In some embodiments, in step 2), the aqueous solution or aqueous suspension SA2 is heated, preferably to a temperature of 5°C to 95°C, preferably greater than 10°C to 60°C, and more preferably greater than 20°C to 40°C.

[0078] Heating during distillation can be carried out by various techniques. Examples include, but are not limited to, heating with steam, heating with hot water, heating with electricity, heating by vapor compression, or heating using a heat pump. Therefore, the distillation apparatus may be a double-wall type in which a high-temperature heat transfer fluid circulates between two walls.

[0079] The aqueous solution or aqueous suspension SA2 is preferably heated to a temperature of more than 5°C to 95°C, preferably more than 10°C to 60°C, and more preferably more than 20°C to 40°C. When heating the aqueous solution or aqueous suspension SA2, the temperature is advantageously higher than the temperature in step 1).

[0080] The temperature of the aqueous solution or aqueous suspension SA2 rises advantageously with a gradient of 0.1 to 10°C / hour, preferably 0.2 to 9°C / hour, more preferably 0.3 to 8°C / hour, and even more preferably 0.5 to 5°C / hour.

[0081] In some embodiments, the temperature of the aqueous solution or aqueous suspension SA2 rises advantageously in a gradient of 10 to 150°C / hour, preferably 30 to 110°C / hour, more preferably 50 to 100°C / hour, and even more preferably 60 to 90°C / hour.

[0082] The temperature rise does not have to be constant throughout the entire process. For example, the aqueous solution or aqueous suspension SA2 may be heated at a rate of 5°C / hour for the first 3 hours, and then at a rate of 10°C / hour until the final temperature is reached.

[0083] According to another particular embodiment of the present invention, step 2) may include, after step 2'), or instead of step 2'), step 2") (optional), which helps to increase the productivity and profitability of the method of the present invention by promoting the crystallization of ATBS to the crystalline form of its own sodium salt. Step 2") consists of lowering the temperature of the aqueous solution or aqueous suspension SA2.

[0084] The aqueous solution or aqueous suspension SA2 is advantageously cooled to a temperature of 5 to less than 95°C, preferably 10 to less than 60°C, more preferably 20 to less than 40°C, and even more preferably 10 to 40°C.

[0085] In some embodiments, step 2) further includes a cooling step. The cooling step is advantageously carried out at a temperature of 5°C to 95°C, preferably greater than 10°C to 60°C, and more preferably greater than 10°C to 40°C.

[0086] In some embodiments, the temperature in the cooling step decreases with a gradient of 0.1 to 8°C / hour, preferably 0.2 to 8°C / hour, more preferably 0.3 to 8°C / hour, and even more preferably 0.5 to 5°C / hour.

[0087] In some embodiments, the temperature of the cooling step is advantageously lower than the heating temperature of step 2) and / or step 1). In some embodiments, the cooling step is performed on an aqueous solution or aqueous suspension SA2 and / or a concentrated aqueous solution or aqueous suspension SA2 and / or suspension S1.

[0088] If the aqueous solution or aqueous suspension SA2 is cooled (step 2"), the temperature is advantageously lower than the temperature in step 2) and optionally lower than the temperature in step 2').

[0089] According to one preferred embodiment, the temperature in step 2) is the same as or lower than the temperature in step 1).

[0090] In some embodiments, no organic solvent or aqueous solution is added in step 2" to obtain ATBS.Na crystals. The temperature of the solution or aqueous suspension SA2 decreases advantageously at a gradient of 0.1 to 8°C / hour, preferably 0.2 to 8°C / hour, more preferably 0.3 to 8°C / hour, and even more preferably 0.5 to 5°C / hour.

[0091] The rate of temperature reduction does not have to be constant throughout the entire process. For example, the aqueous solution or aqueous suspension SA2 may be cooled at a rate of 5°C / hour for the first 3 hours, and then at a rate of 8°C / hour until it reaches the final temperature.

[0092] While the aqueous solution or aqueous suspension SA2 is being cooled, crystals and suspension S1 in the form of ATBS sodium salt are obtained.

[0093] In a particular embodiment, crystals of the sodium salt of ATBS obtained earlier can be added during this step to modify the formation of the suspension S1, a process called crystal seeding, which allows for better control of the crystallization temperature, crystal size, particle size distribution, purity of the final product, and possibly the yield. Crystals of the sodium salt of ATBS have an X-ray powder diffraction pattern that advantageously includes a group of peaks located at 11.7°, 12.2°, 13.2°, 13.5°, 15.6°, 16.8°, 17.8°, 18.5°, 19.1°, 20.6°, 21.4°, 23.3°, 25.1°, 25.8°, 26.9°, 29.1°, 29.5°, 31.0°, 33.0°, 33.6°, 34.4°, 35.2°, 35.9°, 37.1°, 38.4°, 39.6°, 41.1°, 42.9°, 45.1°, 46.0°, 47.2°, and 47.6° at a 2θ angle (+ / -0.1°).

[0094] According to a particular embodiment of the present invention, the solvent distilled in step 2) may be partially or completely reused to form the aqueous solution or aqueous suspension SA2 of step 1). In other words, the distilled solvent is advantageously reused in the aqueous solution or aqueous suspension SA2, at least partially.

[0095] According to another specific embodiment of the present invention, the distilled solvent may be partially or completely reused in an optional step 4) with or without a pretreatment step, generally for washing the sodium salt crystals of ATBS obtained after step 3) of solid-liquid separation.

[0096] The resulting suspension S1 advantageously contains 30 to 90% by weight of ATBS.Na crystalline form relative to the total weight of suspension S1, preferably 50 to 90% by weight of ATBS.Na crystalline form, more preferably 30 to 80% by weight of ATBS.Na crystalline form, and more preferably 50 to 60% by weight of ATBS.Na crystalline form relative to the total weight of suspension S1.

[0097] During step 2), the pH is advantageously greater than 10, preferably greater than 11, more preferably greater than 12, and even more preferably 13-14.

[0098] ●Step 3 of the method for producing the crystalline form of ATBS sodium salt): The ATBS.Na salt crystals contained in the suspension S1 obtained at the end of step 2) are isolated in the solid-liquid separation step and are in the form of composition C1.

[0099] The solid-liquid separation step can be carried out using various techniques. Examples include, but are not limited to, the use of centrifuges, decanters, filter presses, agitated filters, belt filters, disc filters, or rotary drum filters. Solid-liquid separation is preferably carried out using a centrifuge. Solid-liquid separation may also be carried out by gravity sedimentation.

[0100] Step 3) is advantageously carried out at a temperature of -20 to 40°C, preferably -5 to 30°C. After step 3) of solid-liquid separation, it is preferable not to dry the ATBS sodium salt crystals.

[0101] The isolated composition C1 has a crystalline content of sodium ATBS advantageously at 40-99% by weight, preferably 60-99% by weight, more preferably 60-98% by weight, and even more preferably 80-99% by weight, relative to the weight of composition C1. The remainder of composition C1 may be water and / or solubilized sodium ATBS, and optionally the sodium salt base introduced in step 1).

[0102] At the end of step 3), the crystal is characterized as a crystal of ATBS sodium salt. In one particular embodiment, all or part of the liquid phase obtained after solid-liquid separation is used in the aqueous solution or aqueous suspension SA2 of step 1).

[0103] During step 4), the pH is advantageously controlled to 6-14, preferably 8-14, more preferably 10-14, even more preferably 12-14, and even more preferably 13-14.

[0104] ●Step 4 of the method for producing the above crystalline form of ATBS.Na): In the optional step 4), composition C1, which contains the ATBS.Na crystals obtained at the end of step 3), is washed with a washing solution.

[0105] The washing solution may be water, an aqueous solution of a sodium salt base (which may be saturated or unsaturated), or a solution of ATBS sodium salt (which may be saturated or unsaturated, preferably the crystalline form of ATBS.Na), and a saturated solution of ATBS.Na is preferred.

[0106] Examples of sodium salt solutions include solutions of sodium hydroxide, sodium carbonate, sodium bicarbonate, or mixtures thereof. The washing solution may contain one or more organic solvents.

[0107] The amount of organic solvent may vary as a function of temperature and the amount of sodium salt of ATBS or the amount of sodium salt. Advantageously, the cleaning solution does not contain organic solvents.

[0108] As already shown in Step 1), the organic solvent is advantageously selected from organic acids, amides, alcohols, ketones, ethers, esters, alkanes, halogenated hydrocarbon compounds, nitriles, or mixtures thereof. The organic solvent is preferably selected from acrylonitrile, isopropanol, acetic acid, or mixtures thereof. More preferably, the organic solvent is acrylonitrile.

[0109] In one particular embodiment, the composition C1 obtained at the end of step 3) is cleaned by spraying a cleaning solution onto the composition C1. In one particular embodiment, the composition C1 obtained at the end of step 3) is washed by suspending the composition C1 in a washing solution.

[0110] The weight ratio of the aqueous cleaning solution to composition C1 obtained at the end of step 3) is advantageously 0.05:1 to 10:1, and more preferably 0.1:1 to 5:1. This washing step is advantageously carried out at a temperature of -5 to 40°C, preferably 0 to 30°C. Those skilled in the art know how to adjust the temperature so as not to solubilize the ATBS sodium salt crystals.

[0111] The ATBS sodium salt crystals obtained at the end of this optional step 4) can be isolated from the washing solution in the form of composition C2 by the solid-liquid separation step.

[0112] The solid-liquid separation step can be carried out using various techniques. Examples include, but are not limited to, the use of vertical or horizontal centrifuges, decanters, filter presses, belt filters, disc filters, push filters, or rotary drum filters. Solid-liquid separation can also be carried out by gravity sedimentation.

[0113] In one particular embodiment, all or part of the recovered cleaning solution can be reused in step 4) with or without the pretreatment step.

[0114] In one particular embodiment, all or part of the recovered washing solution can be used in the aqueous solution or aqueous suspension SA2 in step 1), with or without the pretreatment step. The pH of the washing solution in step 5) is advantageously controlled to be between 6 and 14, preferably between 8 and 14.

[0115] ●Step 5 of the method for producing the above crystalline form of ATBS.Na): In the optional step 5), the composition C1 obtained at the end of step 3) or the composition C2 obtained at the end of step 4) is dried.

[0116] The drying step can be carried out using a variety of techniques. Examples include, but are not limited to, the use of all convection drying techniques, conduction drying techniques, or radiation drying techniques (fluidized bed dryers, through-bed dryers, conveyor belt drying, microwaves, heated agitation filters, high-frequency radiation, infrared radiation, and spraying). The drying operation can be carried out under atmospheric pressure or vacuum. The drying step may be performed discontinuously (batch drying) or continuously.

[0117] ●Other steps in the method for producing the aforementioned crystalline form of ATBS.Na: During the manufacturing process, i.e., between steps 1) to 5), and regardless of the step, at least one polymerization inhibitor may be introduced to prevent polymerization that may result in ATBS or a salt thereof. This inhibitor may be selected non-limitingly from hydroquinone, paramethoxyphenol, phenothiazine, 2,2,6,6-tetramethyl(piperidine-1-yl)oxyl, 4-hydroxy-2,2,6,6-tetramethyl(piperidine-1-yl)oxyl, phenylenediamine derivatives, or mixtures thereof.

[0118] The inhibitor is preferably paramethoxyphenol or 4-hydroxy-2,2,6,6-tetramethyl(piperidine-1-yl)oxyl. The amount of the inhibitor introduced relative to the amount of ATBS introduced in step 1) is advantageously 0.001% to 5% by weight, more preferably 0.01% to 1% by weight.

[0119] The inhibitor may be introduced during any one or more steps of this method. The amount added is preferably introduced during step 1). More preferably, the inhibitor is part of the aqueous solution or aqueous suspension SA2 introduced in step 1).

[0120] The manufacturing process (steps 1) to 5)) may be carried out continuously or discontinuously (batch production).

[0121] ●Composition of the water-soluble polymer The water-soluble polymer is obtained from the crystalline form of ATBS.Na, and is advantageously obtained from at least one other monomer selected from hydrophilic nonionic monomers and / or hydrophilic anionic monomers and / or hydrophilic cationic monomers and / or hydrophilic zwitterionic monomers and / or hydrophobic monomers and mixtures thereof. Thus, the water-soluble polymer may be a polymer of several distinct monomers or a homopolymer.

[0122] Advantageously, one or more hydrophilic nonionic monomers usable in the present invention include, in particular, acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethacrylamide, N,N-dialkylacrylamide (e.g., N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N-dialkylmethacrylamide, alkoxylated esters of acrylic acid, N-vinylpyrrolidone, N-methylol(meth)acrylamide, N-vinylcaprolactam, N-vinylformamide (NVF), N-vinylacetamide, N-vinylimidazole, N-vinyl The water-soluble vinyl monomer is selected from the group including lusuccinimide, acryloylmorpholine (ACMO), glycidyl methacrylate, vinyl acetate, glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, acrylonitrile, maleic anhydride, itaconamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, isoprenol and its alkoxylated derivatives, hydroxyethyl (meth)acrylate and its alkoxylated derivatives, hydroxypropyl acrylate and its alkoxylated derivatives, and mixtures thereof. Among the nonionic monomers, the alkyl group is preferably C1-C5, more preferably C1-C3. The alkyl group is preferably a linear alkyl. Preferably, the hydrophilic nonionic monomer is acrylamide.

[0123] The water-soluble polymer preferably contains 0 to 99 mol%, more preferably 5 to 99 mol%, and more preferably 25 to 99 mol%, of nonionic monomers (one or more).

[0124] Advantageously, apart from crystalline ATBS.Na, one or more hydrophilic anionic monomers usable in the present invention can be selected from a broad group. These monomers may have vinyl functional groups (preferably acrylic, maleic, fumaric, malonic, itaconic, or allyl functional groups), and may contain carboxylate groups, phosphonate groups, phosphate groups, sulfate groups, or sulfonate groups, or other anionic charged groups. Examples of suitable monomers include acrylic acid; methacrylic acid; dimethylacrylic acid; itaconic acid; C1-C3 hemiesters of itaconic acid; acryloyl chloride; crotonic acid; maleic acid; fumaric acid; 3-acrylamido-3-methylbutanoic acid; and strongly acidic monomers with sulfonic acid or phosphonic acid functional groups, such as vinyl sulfonic acid, vinyl phosphonic acid, allyl sulfonic acid, methallyl sulfonic acid, 2-methylidenepropane-1,3-disulfonic acid, 2-sulfoethyl methacrylate, sulfopropyl methacrylate, etc. Examples include bisphosphonate, allylphosphonic acid, ethylene glycol methacrylate phosphoric acid, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), 2-acrylamido-2-methylpropanedisulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, diethylallylphosphonate, carboxyethyl acrylate; water-soluble salts of these monomers, e.g., alkali metal salts, alkaline earth metal salts, or ammonium salts thereof (different from the crystalline form ATBS.Na); and mixtures thereof. Preferably, one or more hydrophilic anionic monomers are acrylic acid and / or salts thereof.

[0125] The water-soluble polymer preferably comprises 1 to 100 mol%, preferably 5 to 60 mol%, and more preferably 10 to 50 mol%, of anionic hydrophilic monomers (one or more) (separate from the crystalline form of ATBS.Na), where these percentages include monomers corresponding to the crystalline form of the ATBS sodium salt.

[0126] In one particular embodiment, one or more anionic hydrophilic monomers may be chlorinated separately from the crystalline form of ATBS.Na.

[0127] Chlorination refers to the -R of anionic monomers. a The proton of at least one acidic functional group of the (=O)-OH type (where R represents P, S, or C) is replaced with a metal cation or an ammonium cation, -R a This means that it forms a salt of the (=O)-OX type (where X is a metal cation or an organic cation). In other words, the non-salt form is the acid form of the monomer, for example, in the case of a carboxylic acid functional group, R b Corresponding to -C(=O)-OH, the salt form of the monomer is R b -C(=O)-O - X + (X + This corresponds to the form of an alkaline cation or an organic cation. The chlorination of the acidic functional group of the branched water-soluble polymer may be partial or whole. The salt form preferably corresponds to a salt of an alkali metal (Li, Na, K, etc.), an alkaline earth metal (Ca, Mg, etc.), or an ammonium (e.g., ammonium ion or tertiary ammonium). A preferred salt is a sodium salt.

[0128] Chloridation may occur before, during, or after polymerization. In certain embodiments, the water-soluble polymer preferably comprises 1 to 100 mol%, preferably 20 to 100 mol%, more preferably 50 to 100 mol%, and even more preferably 80 to 100 mol%, of one or more anionic monomers in chloride form.

[0129] Advantageously, one or more hydrophilic cationic monomers usable in the present invention are selected from monomers derived from vinyl-type units (preferably acrylamide, acrylic, allyl, or maleic acid) having a phosphonium or quaternary ammonium functional group. Not particularly limited, Diallyldialkylammonium salts such as diallyldimethylammonium chloride (DADMAC); Acidified or quaternized salts of dialkylaminoalkyl(meth)acrylamides, for example, methacrylamide-propyltrimethylammonium chloride (MAPTAC), acrylamide-propyltrimethylammonium chloride (APTAC); Acidified or quaternized salts of dialkylaminoalkyl acrylates, such as quaternized or dimethylaminoethyl acrylate (DMAEA); Acidified or quaternized salts of dialkylaminoalkyl methacrylates, such as quaternized or dimethylaminoethyl methacrylate (DMAEMA); Acidified or quaternized salts of N,N-dimethylallylamine; Acidified or quaternized salts of diallylmethylamine; Acidified or quaternized salts of diallylamine; Vinylamines obtained by hydrolysis (with a base or acid) of an amide group -N(R2)-CO-R1 (where R1 and R2 are independently hydrogen atoms or an alkylated chain of 1 to 6 carbon atoms), for example, vinylamines obtained from the hydrolysis of vinylformamide; Vinylamines obtained by Hoffmann decomposition; and those mixtures These can be cited. Advantageously, the alkyl group is C1 to C7, preferably C1 to C3, and may be linear, cyclic, saturated, or unsaturated. Preferably, it is quaternized dimethylaminoethyl acrylate.

[0130] Those skilled in the art know how to prepare quaternized monomers, which is done, for example, using an RX-type quaternizing agent (where R is an alkyl group and X is a halogen or sulfate). The term "quaternizing agent" refers to a molecule that can alkylate a tertiary amine.

[0131] The quaternizing agent may be selected from dialkyl sulfates or alkyl halides containing 1 to 6 carbon atoms. Preferably, the quaternizing agent is selected from methyl chloride, benzyl chloride, dimethyl sulfate, or diethyl sulfate. Furthermore, the present invention also encompasses DADMAC, APTAC, and MAPTAC monomers in which the counterion is sulfate, fluoride, bromide, or iodide instead of chloride.

[0132] The water-soluble polymer preferably contains 0 to 20 mol%, more preferably 0 to 6 mol%, of cationic monomers (one or more). Advantageously, the zwitterionic hydrophilic monomer(s)(one or more) may be a derivative of a vinyl-type unit(s)(preferably acrylamide, acrylic, allyl, or maleic acid) having a quaternary amine functional group or an ammonium functional group and a carboxylic acid (or carboxylate) functional group, a sulfonic acid (or sulfonate) functional group, or a phosphoric acid (or phosphate) functional group. In particular, not limited to, Dimethylaminoethyl acrylate derivatives such as 2-((2-(acryloyloxy)ethyl)dimethylammonio)dimethylammonio)ethane-1-sulfonate, 3-((2-(acryloyloxy)ethyl)dimethylammonio)propane-1-sulfonate, 4-((2-(acryloyloxy)ethyl)dimethylammonio)butane-1-sulfonate, and [2-(acryloyloxy)ethyl](dimethylammonio)acetate. Dimethylaminoethyl methacrylate derivatives such as 2-((2-(methacryloyloxy)ethyl)dimethylammonio)ethane-1-sulfonate, 3-((2-(methacryloyloxy)ethyl)dimethylammonio)propane-1-sulfonate, 4((2-(methacryloyloxy)ethyl)dimethylammonio)butane-1-sulfonate, and [2-(methacryloyloxy)ethyl](dimethylammonio)acetate. Dimethylaminopropylacrylamide derivatives such as 2-((3-acrylamidopropyl)dimethylammonio)ethane-1-sulfonate, 3-((3-acrylamidopropyl)dimethylammonio)propane-1-sulfonate, 4-((3-acrylamidopropyl)dimethylammonio)butane-1-sulfonate, and [3-(acryloyloxy)propyl](dimethylammonio)acetate. Dimethylaminopropylmethylacrylamide derivatives such as 2-((3-methacrylamidopropyl)dimethylammonio)ethane-1-sulfonate, 3-((3-methacrylamidopropyl)dimethylammonio)propane-1-sulfonate, 4-((3-methacrylamidopropyl)dimethylammonio)butane-1-sulfonate, and [3-(methacryloyloxy)propyl](dimethylammonio)acetate. and mixtures thereof One could list these:

[0133] Other hydrophilic zwitterionic monomers may also be used, in particular the hydrophilic zwitterionic monomer described by the applicant in International Patent Publication No. 2021 / 123599. The water-soluble polymer preferably contains 0 to 20 mol%, more preferably 0 to 10 mol%, of zwitterionic monomers (one or more).

[0134] Distribution coefficient K greater than 1 ow Hydrophobic monomers having the following properties can also be used in the preparation of polymers according to the present invention. The hydrophobic monomer is preferably selected from the following list: (i) C4-C30 alkyl chains, or (ii) arylalkyl (C4-C30 alkyl, C4-C30 aryl) chains, or (iii) propoxylated chains, or (iv) ethoxylated chains, or (v) (meth)acrylic acid esters having ethoxylated and propoxylated chains; Alkylaryl sulfonates (C4-C30 alkyl, C4-C30 aryl); (i) C4-C30 alkyl chains, or (ii) arylalkyl (C4-C30 alkyl, C4-C30 aryl) chains, or (iii) propoxylated chains, or (iv) ethoxylated chains, or (v) monosubstituted or disubstituted (meth)acrylamide amides having ethoxylated and propoxylated chains; Anionic or cationic monomer derivatives of (meth)acrylamide or (meth)acrylic acid having hydrophobic chains; Vinylpyridine and A mixture of those. The hydrophobic monomer may contain a halogen atom, such as chlorine. Among these hydrophobic monomers: The alkyl group is preferably C4-C20, more preferably C4-C8. C6-C20 alkyl groups are preferably linear, while C4-C5 alkyl groups are preferably branched. The arylalkyl group is preferably C7-C25, more preferably C7-C15. The ethoxylated chain preferably contains 1 to 200, more preferably 6 to 100, and more preferably 10 to 40 -CH2-CH2-O- groups. The propoxylated chain preferably contains 1 to 50, more preferably 1 to 20, -CH2-CH2-CH2-O- groups.

[0135] Preferred hydrophobic monomers belonging to these classes include, for example: n-hexyl(meth)acrylate, n-octyl(meth)acrylate, octyl(meth)acrylamide, lauryl(meth)acrylate, lauryl(meth)acrylamide, myristyl(meth)acrylate, myristyl(meth)acrylamide, pentadecyl(meth)acrylate, pentadecyl(meth)acrylamide, cetyl(meth)acrylate, cetyl(meth)acrylamide, oleyl(meth)acrylate, oleyl(meth)acrylamide, erucyl(meth)acrylate, erucyl(meth)acrylamide, N-tert-butyl(meth)acrylamide, 2-ethylhexylacrylate, C4-C22 itaconic acid hemiesters, acidified or quaternized salts of C4-C22 dialkylaminoalkyl(meth)acrylates, acidified or quaternized salts of C4-C22 dialkylaminoalkyl(meth)acrylamides, vinylpyridine, acrylamide undecanoic acid, and mixtures thereof.

[0136] • Cationic allyl derivatives of formula (I) or (II): [ka] (In the formula, R is independently an alkyl chain containing 1 to 4 carbon atoms, R1 is an alkyl or arylalkyl chain containing 8 to 30 carbon atoms, and X is a halide selected from the group consisting of bromides, chlorides, iodides, fluorides, and any negatively charged counterions.) And, preferably, a (meth)acryloyl-type hydrophobic cationic derivative corresponding to formula (III): [ka] (In the formula, A represents O or N-R5 (preferably A represents N-R5), R2, R3, R4, R5, R6, and R7 are independently alkyl chains containing hydrogen or 1 to 4 carbon atoms, Q is an alkyl chain containing 1 to 20 carbon atoms, R8 is an alkyl or arylalkyl chain containing 8 to 30 carbon atoms, and X is a halide selected from the group consisting of bromides, chlorides, iodides, fluorides, and any negatively charged counterions.) These are some examples.

[0137] The water-soluble polymer preferably contains less than 5 mol% of hydrophobic monomer. If the water-soluble polymer contains a hydrophobic monomer, the hydrophobic monomer is present in an amount that allows the polymer to remain soluble in water.

[0138] Monomers with fluorescent properties can also be used in this invention. Monomers with fluorescent properties may be detected by any suitable method, for example, by fluorescence measurement using a fixed-wavelength fluorometer. Generally, monomers with fluorescent properties are detected at maximum excitation and maximum emission, which can be determined using a scanning fluorometer. Monomers having fluorescent properties are selected, for example, from the following monomers: sodium styrenesulfonate or potassium styrenesulfonate, styrenesulfonic acid, vinylimidazole and its derivatives, 9-vinylanthracene and its derivatives, N-9-xanthenylacrylamide and its derivatives, allyldibenzosverenol and its derivatives, tinconisine and its derivatives, quininone and its derivatives, cinconinone and its derivatives, N,N-dimethyl-N-[3-[N'-(4-m'ethoxynaphthalimide)]]propyl-N-(2-hydroxy-3-allyloxy)propylammonium hydroxide, and mixtures thereof. Other fluorescent compounds can also be used if they are functionalized with an allyl double bond, a vinyl double bond, or an acrylic double bond, such as pyranine and its derivatives, coumarin and its derivatives, quinolaxin and its derivatives, pinacyanol and its derivatives, xanthidol and its derivatives, dabusil and its derivatives, 3-hydroxy-2-methylene-3-(1-naphthyl)propionic acid and its derivatives, rhodamine and its derivatives, N-dibenzoberylacrylamide and its derivatives, naphthalene derivatives, fluorescein and its derivatives, pyrene and its derivatives, carbostyryl and its derivatives, pyrazoline and its derivatives, and mixtures thereof.

[0139] In a preferred embodiment, the polymer does not contain monomers having fluorescent properties. In a particular embodiment of the present invention, the water-soluble polymer may comprise at least one cyclic monomer having hydrolytic functionality. Advantageously, the one or more cyclic monomers having hydrolytic functionality are selected from cyclic ketene acetals, thionolactones, and mixtures thereof.

[0140] The cyclic ketene acetal is advantageously selected from 2-methylene-1,3-dioxepane (MDO), 5,6-benzo-2-methylene-1,3-dioxepane (BMDO), 2-methylene-4-phenyl-1,3-dioxolane (MPDL), 2-methylene-1,3,6-trioxocan (MTC), and mixtures thereof. Preferably, the cyclic ketene acetal is 2-methylene-1,3-dioxepane (MDO).

[0141] The thionolactone is advantageously selected from dibenzo[c,e]oxepin(7H)-5-thion (DOT), ε-thionocaprolactone, 3,3-dimethyl-2,3-dihydro-5H-benzo[e][1,4]dioxepin-5-thion (DBT), and mixtures thereof. Preferably, the thionolactone is 3,3-dimethyl-2,3-dihydro-5H-benzo[e][1,4]dioxepin-5-thion.

[0142] In a particular embodiment of the present invention, the water-soluble polymer may contain at least one group having an LCST. According to the general knowledge of those skilled in the art, a group having an LCST corresponds to a group whose water solubility, for a given concentration, is modified as a function of salt concentration above a certain temperature. This is a group that has a heating transition temperature that defines a lack of affinity with the solvent medium. This lack of affinity with the solvent results in opacity or loss of transparency, which can be due to precipitation, aggregation, gelation, or viscosity of the medium. The minimum transition temperature is known as the LCST (lower critical solution temperature). For each concentration of a group having an LCST, a heating transition temperature is observed. This is higher than the LCST, which is the minimum point on the curve. Below this temperature, the polymer is soluble in water. Above this temperature, the polymer loses its solubility in water.

[0143] In a particular embodiment of the present invention, the water-soluble polymer may contain at least one group having UCST. According to the general knowledge of those skilled in the art, a group having UCST corresponds to a group whose water solubility, for a given concentration, is modified as a function of salt concentration below a certain temperature. This is a group that has a cooling transition temperature that defines a lack of affinity with the solvent medium. This lack of affinity with the solvent results in opacity or loss of transparency, which can be due to precipitation, aggregation, gelation, or viscosity of the medium. The maximum transition temperature is known as UCST (upper critical solution temperature). For each concentration of a group having UCST, a cooling transition temperature is observed. This is lower than UCST, which is the maximum point on the curve. Above this temperature, the polymer is soluble in water; below this temperature, the polymer loses its solubility in water.

[0144] The amounts of various monomers (one or more) are adjusted by those skilled in the art so as not to exceed 100 mol% when preparing the water-soluble polymer.

[0145] ●Water-soluble polymer The 2-acrylamido-2-methylpropanoic acid used to obtain the aforementioned water-soluble polymer is, advantageously, 50 mol% or more, preferably 70-100 mol%, of the crystalline form of ATBS.Na before polymerization. More preferably, 100 mol% of the ATBS used is the crystalline form of ATBS.Na.

[0146] In a particular embodiment of the present invention, the water-soluble polymer comprises 1 to 100 mol% of ATBS, preferably 5 to 100 mol% of ATBS, and more preferably 25 to 100 mol% of ATBS; advantageously, 50 mol% or more of the ATBS used, preferably 70 to 100 mol%, is the crystalline form of ATBS.Na. More preferably, 100 mol% of the ATBS used is the crystalline form of ATBS.Na.

[0147] In one preferred embodiment of the present invention, the water-soluble polymer contains only anionic monomer units and nonionic monomer units. In other words, it is preferable to obtain it from at least one anionic hydrophilic monomer and at least one nonionic hydrophilic monomer.

[0148] In a particular embodiment of the present invention, the water-soluble polymer is an acrylamide and ATBS-based polymer, and 50 mol% or more of the ATBS used is the crystalline form of ATBS.Na before polymerization. Preferably, the water-soluble polymer is a polymer consisting of acrylamide, acrylic acid, and ATBS, and 50 mol% or more of the ATBS is the crystalline form of ATBS.Na before polymerization.

[0149] In one preferred embodiment of the present invention, the water-soluble polymer is a homopolymer of ATBS, and 50 mol% or more of the ATBS used is the crystalline form of ATBS.Na.

[0150] The water-soluble polymer may be partially or entirely post-hydrolyzed. According to the present invention, the water-soluble polymer may have a linear, branched, crosslinked, star-shaped, or comb-shaped structure. This structure can be obtained, according to the general knowledge of those skilled in the art, by, for example, by selecting an initiator, a transfer agent, polymerization techniques such as RAFT (reversible addition-cleavage chain transfer), NMP (nitroxide-mediated polymerization), or ATRP (atomic transfer radical polymerization), incorporating structural monomers, or selecting their concentrations.

[0151] The water-soluble polymer may be further composed of branching agents. The structured polymer is a nonlinear polymer having side chains such that when dissolved in water, the polymer exhibits a high degree of entanglement, resulting in a very high low gradient viscosity.

[0152] The branching agent is advantageously selected from the following: The structural agent can be selected from the group including polyethylene unsaturated monomers such as vinyl functional groups (having at least two unsaturated functional groups), particularly allyl functional groups or acrylic functional groups, for example, methylenebisacrylamide (MBA), triallylamine or tetraallylammonium chloride or 1,2-dihydroxyethylenebis-(N-acrylamide). • A monomer having at least two epoxy functional groups, • A monomer having at least one unsaturated functional group and one epoxy functional group. Macroinitiators such as polyperoxides and polyazoids, and transfer agents such as polymer mercaptan polymers and polyols. ·Functionalized polysaccharides, • Water-soluble metal complex consisting of the following: *For example and not limited to, metals having a valency of more than 3, such as aluminum, boron, zirconium, or titanium, and * Ligand having a hydroxyl functional group.

[0153] The amount of branching agent in the water-soluble polymer is advantageously less than 40,000 ppm, preferably less than 10,000 ppm, and more preferably less than 5,000 ppm, relative to the total weight of the monomers of the water-soluble polymer.

[0154] In one particular embodiment, the amount of branching agent is 0.1 ppm or more, preferably 1 ppm or more, relative to the total weight of the monomers of the water-soluble polymer. If the water-soluble polymer contains a branching agent, the polymer remains soluble in water. Those skilled in the art know how to adjust the amount of branching agent, and possibly the amount of transfer agent, required to obtain this result.

[0155] In one preferred embodiment of the present invention, the water-soluble polymer does not contain a branching agent. In a particular embodiment of the present invention, the water-soluble polymer includes a transfer agent. The transport agents are advantageously methanol; isopropyl alcohol; sodium hypophosphate; calcium hypophosphate; magnesium hypophosphate; potassium hypophosphate; ammonium hypophosphate; formic acid; sodium formate; calcium formate; magnesium formate; potassium formate; ammonium formate; 2-mercaptoethanol; 3-mercaptopropanol; dithiopropylene glycol; thioglycerol; thioglycolic acid; thiohydroacrylic acid; thiolactic acid; thiomalic acid; cysteine; aminoethanethiol; thioglycolate; allyl phosphite; allyl mercaptan such as n-dodecyl mercaptan; sodium methallyl sulfonate; methallyl sulfonate Selected from calcium phosphate; magnesium methallyl sulfonate; potassium methallyl sulfonate; ammonium methallyl sulfonate; alkyl phosphites such as trialkyl (C12-C15) phosphites, dioleyl-hydrogen phosphites, and dibutyl phosphites; dialkyldithiophosphates such as dioctyl phosphonates; tertiary nonyl mercaptans; 2-ethylhexyl thioglycolate; n-octyl mercaptans; n-dodecyl mercaptans; tertiary dodecyl mercaptans; isooctyl thioglycolates; 2-ethylhexyl thioglycolate; 2-ethylhexyl mercaptoacetate; polythiols; and mixtures thereof. Preferably, sodium hypophosphate or sodium formate.

[0156] The amount of the transfer agent in the water-soluble polymer is advantageously 0 to 100,000 ppm, preferably 0 to 10,000 ppm, more preferably 0 to 1,000 ppm, and even more preferably 0 to 100 ppm, relative to the total weight of the monomers of the polymer. When present, the transfer agent accounts for 0.1 ppm or more, and preferably 1 ppm or more, relative to the total weight of the monomers of the water-soluble polymer.

[0157] In a particular embodiment of the present invention, the water-soluble polymer does not contain a transfer agent. Generally speaking, the water-soluble polymer does not require the development of a specific polymerization method. In fact, the water-soluble polymer may be obtained using any polymerization technique well known to those skilled in the art. These include solution polymerization; gel polymerization; precipitation polymerization; emulsion polymerization (aqueous or reversed phase); suspension polymerization; reaction extrusion polymerization; water-in-water polymerization; or micelle polymerization.

[0158] Polymerization is generally radical polymerization, preferably radical polymerization by reverse-phase emulsion polymerization or gel polymerization. Radical polymerization includes free radical polymerization using UV initiators, azo initiators, redox initiators, or thermal initiators, as well as controlled radical polymerization (CRP) or matrix polymerization techniques.

[0159] Controlled radical polymerization techniques include, but are not limited to, iodine transfer polymerization (ITP), nitroxide-mediated polymerization (NMP), atom transfer radical polymerization (ATRP), reversible addition-cleavage-chain transfer (RAFT) polymerization (which includes MADIX (polymer design by xanthate exchange) technology), various variations of organometallic radical polymerization (OMRP), and organic heteroatom-mediated radical polymerization (OHRP).

[0160] As already shown, the water-soluble polymer may be post-hydrolyzed. Post-hydrolysis is a hydrolysis reaction of a polymer formed by the polymerization of monomers (one or more). This step involves reacting the hydrolyzable functional groups of the monomers, preferably nonionic functional groups, and more preferably amide or ester functional groups, with a hydrolyzing agent. This hydrolyzing agent may be an enzyme, an ion exchange resin, or a Brønsted acid (e.g., a hydrohalic acid) or a Brønsted base (e.g., an alkali hydroxide or alkaline earth hydroxide). Preferably, the hydrolyzing agent is a Brønsted base. During this step of post-hydrolysis of the water-soluble polymer, the number of carboxylic acid functional groups increases. In fact, the reaction between the base and the amide or ester functional groups present in the water-soluble polymer produces carboxylate groups.

[0161] The water-soluble polymer may be in liquid, gel, or solid form if its preparation involves a drying step such as spray drying, drum drying, radiation drying such as microwave drying, or drying in a fluidized bed.

[0162] The aforementioned water-soluble polymer is advantageously 1 × 10 6 g / mol or more, preferably 2 × 10⁻⁶ 6 ~40×10 6 g / mol, comfortable 5 × 10 6 ~30×10 6 It has a weight-average molecular weight of g / mol. Molecular weight is defined as weight-average molecular weight.

[0163] The weight-average molecular weight is determined by the intrinsic viscosity of the polymer. Intrinsic viscosity can be measured by methods known to those skilled in the art, and can be calculated from the reduced viscosity values ​​for various polymer concentrations by a graphing method consisting of plotting the reduced viscosity value (y-axis) against the concentration (x-axis) and extrapolating the curve to the 0 concentration. The intrinsic viscosity value is plotted on the y-axis or using the least squares method. The molecular weight can then be determined using the Mark-Houwink equation:

[0164] [η]=KM α [η] represents the intrinsic viscosity of the polymer as determined by the solution viscosity method. K represents the experimental constant. M represents the molecular weight of the polymer. α represents the Mark-Houwink coefficient. K and α depend on the specific polymer-solvent system.

[0165] The water-soluble polymer has a filtration ratio called FR, which is advantageously less than 1.5, preferably less than 1.3, and more preferably less than 1.1. The term "filtration ratio" in this document is used to refer to a test used to determine the performance of a polymer solution under conditions similar to the permeability of an ore deposit. This test consists of measuring the time required for a given volume / concentration of solution to pass through a filter. FR generally compares the filtration performance of a polymer solution for two consecutive equivalent volumes, which indicates the tendency of the solution to clog the filter. A lower FR indicates better performance.

[0166] The test used to determine FR includes measuring the time required for a given volume of a 1000 ppm (by weight) polymer solution to flow through a filter. The solution is contained in a cell pressurized to 2 bar, and the filter has a diameter of 47 mm and a predetermined pore size. FR is typically measured using filters with pore sizes of 1.2 μm, 3 μm, 5 μm, or 10 μm.

[0167] The time (t 100ml ) required to obtain 100 ml of filtrate; the time (t 200ml ) required to obtain 200 ml, and the time (t 300ml ) required to obtain 300 ml are measured, and then FR is defined as follows: [Number] The time is measured to the 0.1 s digit.

[0168] Therefore, FR represents the ability of a polymer solution to clog a filter for two consecutive equivalent volumes. The polymer used according to the present invention has improved resistance to chemical and thermal decomposition compared to a polymer of equivalent molecular weight obtained from ATBS that is not in the crystalline form of the sodium salt.

[0169] The test used to measure resistance to chemical decomposition involves preparing a polymer solution of a given concentration in a given brine under aerobic conditions, and then contacting the polymer solution with chemical contaminants such as iron or hydrogen sulfide. The viscosity of the polymer solution is measured before and after 24 hours of exposure to the contaminants. Viscosity measurements are performed under the same temperature and shear gradient conditions.

[0170] The test used to measure resistance to mechanical decomposition involves preparing a polymer solution of a given concentration in brine of a given composition under anaerobic conditions (e.g., using an inert glove box inactivated with nitrogen), and aging it for a given time in a stainless steel cell set to a given temperature. The stainless steel cell is then cooled to room temperature, and the viscosity of the polymer solution contained within the stainless steel cell is measured and compared to its initial value. All handling of the stainless steel cell is carried out in a glove box to avoid exposure to oxygen. The stainless steel cell is sealed to prevent oxygen from entering the solution during heating aging. Viscosity measurements before and after aging are performed in a glove box under the same temperature and velocity gradient conditions.

[0171] Resistance to chemical and thermal decomposition is expressed as a percentage and quantified by the viscosity reduction value determined at the end of the test:

number

[0172] ● Enhanced recovery method for hydrocarbons (oil and / or gas) The present invention relates to an enhanced recovery method for hydrocarbons (oil and / or gas), comprising the following steps: a) Prepare an injection fluid containing at least one water-soluble polymer of ATBS using water or brine. Here, the ATBS is prepared in the crystalline form of ATBS sodium salt (ATBS.Na) having an X-ray powder diffraction pattern containing a group of peaks located at 11.7°, 12.2°, 13.2°, 13.5°, 15.6°, 16.8°, 17.8°, 18.5°, 19.1°, 20.6°, 21.4°, 23.3°, 25.1°, 25.8°, 26.9°, 29.1°, 29.5°, 31.0°, 33.0°, 33.6°, 34.4°, 35.2°, 35.9°, 37.1°, 38.4°, 39.6°, 41.1°, 42.9°, 45.1°, 46.0°, 47.2°, and 47.6° in 2θ angle before polymerization; b) Injecting a fluid into the subsurface layer; c) Using the aforementioned injection fluid to sweep the subsurface layer; d) Recover the aqueous hydrocarbon mixture.

[0173] When the water-soluble polymer used in the preparation of the injection fluid is in powder form, the average particle size of the water-soluble polymer particles is advantageously less than 1.5 mm, preferably less than 850 μm. The average particle size of the water-soluble polymer particles is advantageously greater than 5 μm.

[0174] The average particle size of water-soluble polymer particles is the average diameter of the maximum dimensions, for example, the diameter in the case of spherical particles. This is advantageously measured using a laser measuring device employing the prior art, which is part of the knowledge of those skilled in the art. For example, a Malvern Mastersizer, such as the MS2000, can be used for this purpose. Using this type of device, the particle size distribution of particles in a liquid medium or in solid form can be measured by laser diffraction.

[0175] If the water-soluble polymer is in particulate form, it may be dissolved in an aqueous medium within the dispersion device. The polymer slicing unit (PSU) described in U.S. Patent No. 8,186,871 is an example of a dispersion device that can be used to prepare concentrated polymer aqueous solutions.

[0176] The water or brine used to prepare the injection fluid may be production water. “Production water” refers to all saline or non-saline water, brine, seawater, or aquifer water from the hydrocarbon reservoir. This production water may be treated before the injection fluid is prepared, as described in International Patent Publication No. 2018 / 020175.

[0177] The water-soluble polymer may be combined with a stabilizing compound. The stabilizing compound (stabilizer) may be a compound that adequately protects the polymer, for example, from thermal, chemical, and / or mechanical degradation. Examples of suitable stabilizers are described in International Patent Application Publication No. 2010 / 133258.

[0178] Depending on the technique used, the injection fluid containing the water-soluble polymer is injected alone or in combination with one or more chemical compounds that can be used for enhanced recovery of hydrocarbons (oils and / or gases). These chemical compounds involve the use of weak, strong, or super-strong mineral or organic bases that can saponify crude oil and produce in-situ surface-active species that solubilize hydrocarbons, particularly oils. Examples include sodium carbonate or potassium carbonate, caustic soda, borate and metaborate compounds, amines, and basic polymer species. Another family of compounds commonly injected with polymers is the family of surfactants, which are often anionic, amphoteric, cationic, and sometimes nonionic. These compounds are rarely injected in their pure form, but are generally injected with co-surfactants and co-solvents to improve their compatibility and effectiveness in reservoirs (subterranean layers).

[0179] The injection fluid preferably contains the water-soluble polymer in an amount of 10 to 15,000 ppm by weight, preferably 50 to 10,000 ppm by weight, and more preferably 100 to 5,000 ppm by weight.

[0180] Surprisingly, the applicant has found that the water-soluble polymer obtained from the aforementioned crystalline form of ATBS sodium salt exhibits better filterability and better resistance to chemical and thermal decomposition than polymers of equivalent molecular weight obtained from ATBS that are not the aforementioned crystalline form of sodium salt. It is also known that filterability decreases as the molecular weight of the polymer increases. One of the advantages of the present invention is the possibility of obtaining a very high molecular weight water-soluble polymer that simultaneously exhibits good filterability. Furthermore, the concentration of the water-soluble polymer required to bring the injection fluid to the target viscosity is reduced, which improves the economic conditions for recovering hydrocarbons (oil and / or gas) contained in subsurface layers.

[0181] The purpose of the water-soluble polymer according to the present invention is to increase the viscosity of water injected into a reservoir (subterranean layer) containing hydrocarbons (oil and / or gas) in order to ensure mobility control without the need for chemical crosslinking between chains.

[0182] In one particular embodiment, an enhanced recovery method for hydrocarbons (oils and / or gases) includes the following steps: a) 5 × 10 6 To prepare an injection fluid containing the water-soluble polymer having a molecular weight exceeding g / mol: Here, The aforementioned injection fluid has a salt concentration exceeding 100 g / l, and the amount of divalent salts (one or more types) contained therein is 50 g / l or less; The polymer, before polymerization, contains 80 mol% or more of the crystalline form of ATBS.Na relative to ATBS, preferably 50 mol% or more, more preferably 70 mol% or more, and more preferably 100 mol%; The concentration of the water-soluble polymer in the injection fluid is less than 3,000 ppm by weight; The injectable fluid has viscosity V1 before step b); b) Shear the injectable fluid to obtain a viscosity reduction of more than 25% relative to V1:

number

[0183] The shear step can be performed, for example, using a valve, a port, or a pump. Preferably, the concentration of the divalent salt (one or more) in the injection fluid is 3 to 50 g / l.

[0184] A carbonate layer is a sedimentary rock layer having a carbonate composition of 50% or more. The present invention and its advantages will be better understood in light of the following figures and examples provided to illustrate the present invention non - limitatively.

[0185] ▲Example ● Example 1: Synthesis of 2 - acrylamido - 2 - methylpropane sulfonic acid (ATBS) (A H ) 1522 g of acrylonitrile containing 0.4 wt% of water is added to a 2000 ml reactor with a double jacket and stirring, the mixture is stirred for 1 hour, cooled by the double jacket of the reactor to maintain the temperature of the sulfonation mixture at - 20 °C, and then 180 g of fuming sulfuric acid having a titer of 104% H2SO4 (18% fuming sulfuric acid) is added.

[0186] 97 g of isobutylene is added to the above sulfonation mixture at a rate of 1.6 g / min.

[0187] When adding the isobutylene, the temperature of the mixture is controlled to 45°C. 2-acrylamido-2-methylpropanesulfonic acid particles precipitate from the mixture, with a solid content of approximately 20% by weight. This reaction mixture is filtered through a Buchner funnel and dried under vacuum at 50°C. The resulting solid is 2-acrylamido-2-methylpropanesulfonic acid (ATBS A) in the form of a very fine white powder. H ) Optical microscope observation (Figure 12) was performed using ATBS A H This shows that the crystals have a needle-like morphology.

[0188] ●Example 2a: 2-acrylamido-2-methylpropanesulfonate sodium salt (ATBS,Na A Na 2a) Formation of the aforementioned crystal form (the present invention) Add 439 g of 22% (by weight in water) sodium hydroxide solution to a 1000 ml double-jacketed stirred reactor with stirring. Add 452 g of ATBS A from Example 1. H Add the above mixture.

[0189] The mixture is stirred at 10°C for 30 minutes to form an aqueous solution SA2. The aqueous solution SA2 is heated to a temperature of 40°C for 20 minutes under a vacuum of 50 mbar, then the temperature is maintained under a vacuum of 50 mbar for 30 minutes and cooled to a temperature of 10°C. The cooling time from 40°C to 10°C is 6 hours. A suspension S1 of ATBS.Na crystals is obtained. This suspension S1 is filtered using a Robatel vertical centrifuge. Na A solid of composition C1 containing 80% by weight of 2a) is obtained.

[0190] Optical microscope observation (Figure 13) shows crystal A Na This shows that 2a has columnar and platelet forms.

[0191] ●Example 2b: The crystalline form of ATBS sodium salt (ATBS.Na A Na Formation of 2b) A crystal of ATBS.Na Na 2b is prepared according to the procedure described in Example 2a, except that SA2 is distilled at 700 mbar.

[0192] Optical microscopy observation (Figure 14) shows crystal A obtained under these conditions. Na 2b is a crystal of ATBS.Na prepared in Example 2a. Na This shows that it is identical to 2a.

[0193] ●Example 2c: The crystalline form of ATBS sodium salt (ATBS.Na A Na 2c) Formed A crystal of ATBS.Na Na 2c is prepared according to the procedure described in Example 2a, except that the cooling time is shortened to 3 hours and 45 minutes. Optical microscopy observation (Figure 15) shows that the crystals obtained under these conditions are crystals of ATBS.Na. Na This shows that it is identical to 2a.

[0194] ●Comparative Example 2a: Preparation of ATBS.Na crystals at atmospheric pressure (1 bar) (not obtained) (CE-A Na 2a) The reaction is carried out according to the procedure described in Example 2a, except that SA2 is distilled at atmospheric pressure. At the end of the cooling step, suspension S1 cannot be formed from aqueous solution SA2, and filtration or centrifugation for isolating ATBS sodium salt crystals cannot be performed.

[0195] ●Comparative Example 2b: Preparation of ATBS sodium salt crystals (not obtained) (CE-A Na 2b) The reaction was carried out according to the conditions described in Example 27 of Patent Application US6331647. Add 124 g of sodium hydroxide and 0.13 g of hydroquinone monomethyl ether to a double-jacketed 5000 ml reactor containing 400 g of water, with stirring. Stir the medium until all of the sodium hydroxide is dissolved.

[0196] 632g ATBS A H Add the above mixture. Stir this mixture at 10°C for 30 minutes to form an aqueous solution of the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid.

[0197] The resulting aqueous solution is filtered in a 3000 ml reactor equipped for distillation and containing an air purge tube. The contents are heated and stirred while air is blown in below the surface at a rate of 0.5 cubic feet per hour. The contents are heated to 50°C under a vacuum of 933 mbar (approximately 700 mm of mercury). As the water is removed, a yellowish, honey-like product is formed. This product is then transferred to a Robatel vertical centrifuge, but no solid was recovered. Since no solid sample was obtained, optical microscopy observation was impossible (Figure 16).

[0198] ●Comparative Example 2c: Preparation of ATBS sodium salt crystals (not obtained) (CE-A Na 2c) The reaction was carried out according to the conditions described in Example 3 of patent application WO2013 / 079507. A 100g solution of ATBS.Na (16.77% by weight) was obtained according to Example 1 of 2013 / 079507.

[0199] While introducing air into the ATBS.Na solution, 50 g of solvent (a mixture of acrylonitrile and methanol) is removed from the ATBS.Na solution under reduced pressure (less than 700 mbar) and at room temperature. CE-A, which is the solid form of ATBS.Na, is then obtained. Na 2c is formed, filtered, washed with acrylonitrile / methanol, and then dried overnight at 50°C.

[0200] Optical microscopy observation (Figure 17) shows ATBS.Na CE-A Na This shows that the dried solid of 2c does not correspond to the ATBS.Na crystals according to the present invention.

[0201] ●Comparative example 2d: ATBS.Na CE-A NaPreparation of 2d (not according to the present invention) The reaction is carried out according to the procedure described in Example 2a, except that SA2 is distilled at 720 mbar. CE-A, a crystal of ATBS.Na Na A solid of composition C1 containing 80% by weight of 2d is obtained.

[0202] Optical microscopy observation (Figure 18) shows ATBS.Na CE-A Na This shows that the dried solid of 2c does not correspond to the ATBS.Na crystals according to the present invention.

[0203] ●Comparative example 2e: ATBS.NaCE-A Na Preparation of 2e (not according to the present invention) The reaction is carried out according to the procedure described in Example 2a, except that the cooling time is 3 hours and 20 minutes. CE-A, a crystal of ATBS.Na Na A solid of composition C1 containing 80% by weight of 2e is obtained.

[0204] Optical microscopy observation (Figure 19) shows ATBS.Na CE-A Na This demonstrates that the dried solid of 2e does not correspond to the ATBS.Na crystals according to the present invention.

[0205] ●Example 3: ATBS A from Example 1 and Example 2a H and ATBS.Na A Na NMR analysis of product 2a ATBS A H and ATBS.Na A Na 2a is analyzed by proton nuclear magnetic resonance (NMR). The sample is dissolved in D2O. The NMR spectrometer is a Bruker model with a frequency of 400 MHz, and 5 mmBBO BB- 1 H is attached.

[0206] The two proton spectra (Figures 1 and 2) are similar, and the peak assignments are consistent with the molecular structure of ATBS or the sodium salt.

[0207] ●Example 4: ATBS A from Example 1 and Example 2a H and ATBS.Na A Na X-ray diffraction analysis of the 2a product ATBS A H and ATBS.Na A Na The crystals of 2a are pre-pulverized to prepare a powder that will be analyzed by X-ray diffraction over an angular range of 10 to 90°. The instrument used is a Rigaku MiniFlex II diffractometer equipped with a copper source.

[0208] ATBS.Na A Na Crystal 2a exhibits an X-ray diffraction pattern with the following characteristic peaks (Figure 4): At an angle of 2θ (+ / -0.1°), the angles are 11.7°, 12.2°, 13.2°, 13.5°, 15.6°, 16.8°, 17.8°, 18.5°, 19.1°, 20.6°, 21.4°, 23.3°, 25.1°, 25.8°, 26.9°, 29.1°, 29.5°, 31.0°, 33.0°, 33.6°, 34.4°, 35.2°, 35.9°, 37.1°, 38.4°, 39.6°, 41.1°, 42.9°, 45.1°, 46.0°, 47.2°, and 47.6°. ATBS A H The X-ray diffraction patterns (Figure 3) do not have the same group of peaks.

[0209] ●Example 5: ATBS A H and ATBS.Na A Na Fourier transform infrared measurement of 2a The instrument used for Fourier transform infrared measurements is a Perkin Elmer Spectrum 100 with a single reflection ATR polarization accessory, and has an accuracy of 8 cm. -1 That is the case.

[0210] ATBS A H and ATBS.Na crystal A Na Sift 2a into 100 μm particles. Dry the particles remaining on the sieve and place them in a 60°C oven for at least 4 hours. Place several hundred milligrams of solid on the diamond of the ATR accessory and manually apply pressure using the accessory.

[0211] The following bands (Figure 6) are characteristic of crystalline form A of ATBS.Na Na 2a: 3576 cm -1 、3485 cm -1 、3310 cm -1 、3079 cm -1 、2975 cm -1 、1658 cm -1 、1629 cm -1 、1543 cm -1 、1403 cm -1 、1321 cm -1 、1301 cm -1 、1205 cm -1 、1187 cm -1 、1163 cm -1 、1046 cm -1 、980 cm -1 、629 cm -1 。 ATBS A H does not have the same peak group in its infrared spectrum (Figure 5).

[0212] ● Example 6: ATBS A from Examples 1 and 2a H and ATBS.Na A Na 2a products, differential scanning calorimetry (DSC) The apparatus used is a Mettler DSC3. ATBS A H and crystalline A of ATBS.Na Na 2a are analyzed under a nitrogen flow with a heating gradient of 10 °C / min. The initial temperature is 30 °C and the product is heated to 350 °C.

[0213] ATBS A H The thermogram (Figure 7) shows a thermal effect at a temperature of 195.15 °C, generally considered to be the melting / decomposition point of ATBS, followed by two exothermic decomposition phenomena at 212.8 °C and 288.4 °C.

[0214] Crystal A of ATBS.Na Na The thermogram of 2a (Figure 8) shows four thermal phenomena at 49.8°C, 144.8°C, 169.8°C, and 254.3°C.

[0215] ●Example 7: Polymer P1-A of acrylamide (AM) / ATBS (75 / 25 mol%) Na Preparation of 2a 1035g deionized water, 520.5g AM (50 wt% aqueous solution), 16.2g urea, and 285g ATBS.Na A Na Add 2a to a 2000 mL beaker.

[0216] The solution obtained in this way is cooled to 5°C to 10°C, transferred to an adiabatic polymerization reactor, and nitrogen is bubbled through it for 30 minutes to remove any trace amounts of dissolved oxygen.

[0217] Next, the following is added to the reactor: • 0.45 g of 2,2'-azobisisobutyronitrile • 1.5 ml of a 2.5 g / l solution of 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride, • 10 ml of 1 g / l sodium phosphite solution • 1.5 ml of 1 g / l solution of tert-butyl hydroperoxide, • 1.5 ml of a 1 g / l solution of ammonium sulfate and iron(II) hexahydrate (Mohr's salt).

[0218] After a few minutes, the nitrogen inlet is shut off and the reactor is closed. The polymerization reaction continues for 2 to 5 hours until the maximum temperature is reached. The resulting rubbery gel is shredded and dried to obtain a coarse powder, which is then pulverized and sieved to obtain a polymer in powder form. Next, the gel is dried and pulverized to obtain polymer P1-A in powder form. Na We obtain 2a.

[0219] Polymer P2-A Na 2a, P3-A Na 2a and P4-A Na2a is polymer P1-A Na It can be obtained using the method for obtaining 2a, but by varying the amount of sodium hypophosphite. P2-A Na 2a: 1.5 ml of 3 g / l sodium hypophosphite solution P3-A Na 2a: 1 ml of 3 g / l sodium hypophosphite solution P4-A Na 2a: 1.5 ml of 1 g / l sodium hypophosphite solution

[0220] ●Example 8: Preparation of comparative polymers P'1 to P'3, which are AM / ATBS polymers (75 / 25 mol%) Polymer P'1-A H P'2-A H , and P'3-A H It contains 257g of ATBS A H And 99 g of sodium hydroxide is used to a concentration of 50% by weight in water, and P1 to P3 are obtained according to the protocol described in Example 7.

[0221] Polymer P'1-CEA Na 2c, P'2-CEA Na 2c, P'3-CEA Na 2c is obtained using ATBS CE-ANa2c according to the protocol described in Example 7.

[0222] Polymer P'1-CEA Na 2d, P'2-CEA Na 2d, P'3-CEA Na 2d is obtained using ATBS CE-ANa2d according to the protocol described in Example 7.

[0223] Polymer P'1-CEA Na 2e, P'2-CEA Na 2e, P'3-CEA Na 2e is obtained using ATBS CE-ANa2e according to the protocol described in Example 7.

[0224] ●Example 9: Measurement of the filtration ratio of the polymer solution Filtration tests were performed on the polymers prepared in Examples 7 and 8. The results are shown in Table 1.

[0225] A polymer solution was obtained at an active concentration of 1,000 ppm (ppm is by weight) in brine containing water, 30,000 ppm NaCl, and 3,000 ppm CaCl2·2H2O. The filtration ratio (FR) was measured using a 1.2 μm pore size filter, which is representative of low-permeability precipitates.

[0226] Table 1: Polymers tested for filtration ratio [Table 1]

[0227] Table 1 shows the crystalline forms of ATBS.Na with equivalent molecular weight (P1~P3-A Na The polymer obtained from 2a) is always the amorphous form of ATBS.Na (P'1~P'3-A H ) or a polymer obtained from a crystalline form of ATBS.Na that is not according to the present invention has a lower FR. This difference becomes more pronounced as the molecular weight of the polymer increases. 13 × 10 6 A polymer obtained from the aforementioned crystalline form of ATBS.Na having a molecular weight of Da (P4-A Na 2a) is a polymer (11.5 × 10) obtained from the amorphous form of ATBS.Na having a lower molecular weight. 6 Da, P'3-a H ), or polymers obtained from different crystalline forms (P'3-CEA Na It has a lower FR than 2c~e).

[0228] ●Example 10: Measurement of resistance to chemical decomposition of polymer solutions with equivalent molecular weights. The resistance of polymer P3 and comparative polymer P'3 to chemical decomposition was tested under aerobic conditions (ppm by weight) in saline solutions consisting of water, 37,000 ppm NaCl, 5,000 ppm Na2SO4, and 200 ppm NaHCO3, and in the presence of various concentrations of iron(II) (2, 5, 10, and 20 ppm). The results obtained after 24 hours of contact between the polymer solutions and the contaminants are shown in Figure 9.

[0229] The results are shown in Table 2. Table 2: Polymer P3-A against chemical decomposition Na 2a and comparative polymer P'3-A H and P'3-CEA Na Measurement of resistance between 2c and 2e [Table 2]

[0230] For each iron(II) concentration, polymer P3-A Na 2a is the corresponding comparative polymer P'3-A H P'3-CEA Na 2c, P'3-CEA Na 2d, P'3-CEA Na It can be seen that it shows a smaller viscosity decrease than 2e.

[0231] ●Example 11: Measurement of resistance of polymer solutions with equivalent molecular weight to thermal decomposition P3-A Na The thermal decomposition resistance tests of the 2a and P'3 comparative polymers were conducted under anaerobic conditions in a brine solution consisting of 30,000 ppm NaCl and 3,000 ppm CaCl2·2H2O at an active concentration of 2,000 ppm (ppm is by weight). The polymer solutions were aged at 90°C for 6 months. The results obtained regarding viscosity reduction are shown in Figure 10.

[0232] The results are shown in Table 3. Table 3: Polymer P3-A in relation to thermal decomposition Na 2a and P'3-A H P'3-CEANa Measurement of resistance between 2c and e [Table 3]

[0233] P3-A Na 2a is the corresponding comparative polymer P'3-A H and P'3-CEA Na It can be seen that the viscosity decrease is smaller than in 2c to e.

[0234] ●Example 12: Preparation of homopolymers P5-P7 from the crystalline form of ATBS.Na according to the present invention Polymer P5-A Na 2a is polymer P1~P3-A Na 2a is prepared according to the protocol described in Example 7, except that the amounts of monomers and excipients are adjusted to reach the desired molar composition of 100 mol% ATBS (using 30 ml of a 1 g / L solution of sodium hypophosphite).

[0235] Polymer P6-A Na 2a and P7-A Na 2a changes the amount of sodium hypophosphate to polymer P5-A Na Prepared according to the same protocol as 2a (using 1.5 ml of a 1 g / L solution of sodium hypophosphate).

[0236] ●Example 13: Preparation of comparative homopolymers P'5~P'7 of ATBS (not according to the present invention) Comparative polymer P'5-A H P'6-A H , and P'7-A H 452g of ATBS A H The solution is prepared using 175 g of sodium hydroxide at a concentration of 50% by weight in water, according to the protocol described in Example 12.

[0237] Polymer P'5-CEA Na 2c, P'6-CEA Na2c is ATBS.Na CE-A Na It is prepared using 2c. Polymer P'5-CEA Na 2d, P'6-CEA Na 2d is ATBS.Na CE-A Na It is prepared using 2D. Polymer P'5-CEA Na 2e, P'6-CEA Na 2e is ATBS.Na CE-A Na It is prepared using 2e.

[0238] ●Example 14: Measurement of the filtration ratio of polymer solutions of polymers P5-P7 and comparative polymers P'5-P'7 A filtration test was performed on the polymers prepared in Examples 12 and 13. When using the amorphous form of ATBS.Na according to the present invention, 15 × 10 6 Molecular weight grade polymer P7-A of Da Na 2a is not available. The results are shown in Table 4.

[0239] A polymer solution was obtained at an active concentration of 1,000 ppm in saline solution containing water, 30,000 ppm NaCl, and 3,000 ppm CaCl2·2H2O (ppm is by weight). The filtration ratio (FR) was measured using a 1.2 μm pore size filter, which is representative of low-permeability precipitates.

[0240] Table 4: Polymers tested for filtration ratio [Table 4]

[0241] Table 4 shows that, for equivalent molecular weights, polymers obtained from the crystalline form of ATBS.Na according to the present invention always have a lower FR than polymers obtained from the amorphous form of ATBS.Na that are not according to the present invention. This difference becomes increasingly pronounced as the molecular weight of the polymer increases. 15 × 10 6The polymer (P7) obtained from the crystalline form of ATBS.Na having a molecular weight of Da is a polymer (5.3 × 10) obtained from the amorphous form of ATBS.Na having a lower molecular weight. 6 Da, P'6-A H ), or polymers obtained from different crystalline forms (P'6-CEA Na It has a lower FR than 2c-e).

[0242] ●Example 15: Measurement of the resistance of polymer solutions of equivalent molecular weight to chemical decomposition Polymer P6-A Na 2a and comparative polymer P'6-A H and P'6-CEA Na The resistance of 2c to e to chemical decomposition was tested under aerobic conditions (ppm is by weight) in the presence of water, brine consisting of 37,000 ppm NaCl, 5,000 ppm Na2SO4, and 200 ppm NaHCO3, and iron(II) at various concentrations (2, 5, 10, and 20 ppm). The results obtained after 24 hours of contact between the polymer solution and the contaminant are shown in Figure 11.

[0243] The results are shown in Table 5. Table 5: Polymer P6-A according to the present invention against chemical decomposition Na Measurement of resistance of 2a and comparative polymer P'6 [Table 5]

[0244] For each iron(II) concentration, the polymer according to the present invention shows a smaller viscosity reduction than the corresponding comparative polymer P'6.

[0245] ●Example 16: Polymer P8-A of AM / ATBS according to the present invention Na Preparation of 2a (75 / 25 mol%) Polymer P8-A Na2a is prepared according to the protocol described in Example 7 for the preparation of polymer P1, except by adjusting the amounts of monomers and excipients to achieve the desired molar composition (75 / 25) of AM / ATBS.

[0246] Post-hydrolysis of acrylamide: 500.0 g of pre-shredded gel is then mixed with 16.0 g of 50 wt% aqueous sodium hydroxide solution, and this mixture is heated and maintained at a temperature of 90°C for 90 minutes. Next, the gel is dried and pulverized to obtain polymer P8-A in powder form. Na We obtain 2a.

[0247] ●Example 17: Preparation of comparative polymer P'8 of AM / ATBS (75 / 25 mol%). Polymer P'8-A H This was done according to the protocol described in Example 16, provided that 257 g of ATBS A was used. H The solution is prepared using 99.5 g of sodium hydroxide at a concentration of 50% by weight in water. Polymer P'8-CEA Na 2c is prepared according to the protocol described in Example 16, but using CE-ANa2c crystals. Polymer P'8-CEA Na 2d is prepared according to the protocol described in Example 16, but using CE-ANa2d crystals. Polymer P'8-CEA Na 2e is prepared according to the protocol described in Example 16, but using CE-ANa2e crystals.

[0248] ●Example 18: Measurement of the filtration ratio of polymer solution Filtration tests were performed on the polymers obtained in Examples 16 and 17. The results are shown in Table 6. A polymer solution was obtained at an active concentration of 1,000 ppm in saline solution containing water, 30,000 ppm NaCl, and 3,000 ppm CaCl2·2H2O (ppm is by weight). The filtration ratio (FR) was measured using a 3 μm pore size filter, which is representative of low-permeability precipitates.

[0249] Table 6: Filtration ratio of polymer P8 and comparative polymer P'8 according to the present invention [Table 6]

[0250] Table 6 shows the polymers obtained from the aforementioned crystalline form of ATBS.Na despite their higher molecular weight (P8-A Na 2a) is a polymer (P8-A) obtained from the amorphous form of ATBS. H ) or polymers obtained from different crystalline forms (P'8-CEA Na This shows that 2c~e) and FR are equivalent.

[0251] ●Example 19: Preparation of copolymers P9 and P'9 of AM / acrylic acid (AA) / ATBS (75 / 10 / 15 mol%) The amounts of different monomers are adjusted to achieve the desired molar composition of AM / AA acid / ATBS, thereby creating polymer P9-A Na 2a, P'9-A H , and P'9-CEA Na The experimental protocols of Examples 7 and 8 are reproduced, except for obtaining 2c to 2e.

[0252] ●Example 20: Preparation of polymer P10 / P'10 of AM / quaternized dimethylaminoethyl acrylate. CH3Cl(DMEA.MeCl) / ATBS (60 / 5 / 35 mol%) The amounts of various monomers are adjusted to reach the desired molar composition of AM / DMEA.MeCl / ATBS, thereby producing polymer P10-A Na 2a, P'10-A H , and P'10-CEA Na 2c~P'10-CEA NaThe experimental protocols of Examples 7 and 8 are reproduced, except for obtaining 2e.

[0253] ●Example 21: Preparation of polymer P11 / P'11 of AM / diallyldimethylammonium chloride (DADMAC) / ATBS (75 / 5 / 20 mol%) The amounts of various monomers are adjusted to achieve the desired molar composition of AM / DADMAC / ATBS, thereby creating polymer P11-A Na 2a, P'11-A H , and P'11-CEA Na The experimental protocols of Examples 7 and 8 are reproduced, except for obtaining 2c to 2e.

[0254] ●Example 22: Measurement of the resistance of polymer solutions of equivalent molecular weight to chemical decomposition The resistance of the polymers of Examples 19-21 to chemical decomposition was tested under aerobic conditions (ppm by weight) in saline solutions consisting of water, 37,000 ppm NaCl, 5,000 ppm Na2SO4, and 200 ppm NaHCO3, and in the presence of various concentrations of iron(II) (2, 5, 10, and 20 ppm). All polymers had the same chemical composition. The results are shown in Table 7.

[0255] Table 7: Measurement of resistance of polymers in Examples 16-18 to chemical decomposition [Table 7-1] [Table 7-2]

[0256] For each iron(II) concentration, polymers P9 to P11 according to the present invention show a smaller viscosity reduction than their corresponding comparative polymers that were not prepared using the crystalline form of ATBS.Na according to the present invention.

[0257] ●Example 23: Measurement of the filtration ratio of polymer solutions from Examples 19-21 Filtration tests were performed on the polymers prepared in Examples 19-21. The results are shown in Table 8. A polymer solution was obtained at an active concentration of 1,000 ppm in saline solution containing water, 30,000 ppm NaCl, and 3,000 ppm CaCl2·2H2O (ppm is by weight). The filtration ratio (FR) was measured using a 3 μm pore size filter, which is representative of low-permeability precipitates.

[0258] Table 8: Filtration ratios of polymers P9-P11 and comparative polymers P'9-P'11 according to the present invention [Table 8]

[0259] Table 8 shows that despite their higher molecular weight, the polymers obtained from the aforementioned crystalline forms of ATBS.Na (P9-P11) have FR values ​​equivalent to those obtained from amorphous forms of ATBS or polymers obtained from different crystalline forms of ATBS.Na.

Claims

1. Enhanced hydrocarbon recovery method including the following steps: a) Prepare an injection fluid containing at least one water-soluble polymer of 2-acrylamido-2-methylpropanoate ATBS using water or brine; Here, the ATBS is a crystalline form of sodium 2-acrylamido-2-methylpropanoate salt ATBS.Na, which before polymerization has an X-ray powder diffraction pattern containing peaks at 2θ angles of 11.7°, 12.2°, 13.2°, 13.5°, 15.6°, 16.8°, 17.8°, 18.5°, 19.1°, 20.6°, 21.4°, 23.3°, 25.1°, 25.8°, 26.9°, 29.1°, 29.5°, 31.0°, 33.0°, 33.6°, 34.4°, 35.2°, 35.9°, 37.1°, 38.4°, 39.6°, 41.1°, 42.9°, 45.1°, 46.0°, 47.2°, and 47.6°. b) Injecting the aforementioned injection fluid into the underground layer; c) sweeping the underground layer using the injection fluid; d) Recover the aqueous hydrocarbon mixture.

2. The method according to claim 1, characterized in that the injection fluid contains 10 to 15,000 ppm by weight of a water-soluble polymer.

3. The method according to either claim 1 or claim 2, characterized in that 50 mol% or more of the ATBS in the water-soluble polymer is the crystalline form of ATBS.Na before polymerization.

4. The method according to any one of claims 1 to 3, wherein the water-soluble polymer comprises 10 mol% to 100 mol% of one or more anionic monomers, wherein the percentages include monomers corresponding to the crystalline form of ATBS.Na.

5. The method according to any one of claims 1 to 4, characterized in that the water-soluble polymer contains only anionic monomer units and nonionic monomer units.

6. The method according to any one of claims 1 to 5, characterized in that the water-soluble polymer consists of acrylamide and ATBS, and 50 mol% is the crystalline form of ATBS.Na before polymerization.

7. The method according to any one of claims 1 to 6, characterized in that the water-soluble polymer has a filtration ratio of less than 1.

5.

8. The method according to claim 1, characterized in that the water-soluble polymer is a homopolymer of ATBS, and 50 mol% or more of the ATBS is the crystalline form of ATBS.Na before polymerization.

9. The method according to claim 8, characterized in that the water-soluble polymer has a filtration ratio of less than 1.

5.

10. The method according to claim 8 or claim 9, characterized in that the injection fluid contains 10 to 15,000 ppm by weight of a water-soluble polymer.

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