Method for enhanced hydrocarbon recovery using a polymer of the crystalline form of 2-acrylamido-2-methylpropane sulfonic acid sodium salt

Abstract

A method for enhanced hydrocarbon recovery comprising the steps of: a) preparing an injection fluid comprising at least one water-soluble polymer obtained from ATBS; the ATBS being in crystalline form of ATBS sodium salt prior to polymerization, having an X-ray powder diffraction pattern comprising 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°; 47.6° 2 theta angle; with water or brine; b) injecting the injection fluid into a subterranean formation; c) flooding the subterranean formation with the injection fluid; d) recovering a water-containing hydrocarbon mixture.

Description

Technical Field

[0001] This invention relates to a method for improving hydrocarbon (oil and / or natural gas) recovery using a water-soluble polymer obtained from sodium 2-acrylamido-2-methylpropanesulfonate in crystalline form. Background Technology

[0002] Most of the oil fields currently in operation are mature and have, in fact, begun or are about to begin, declining production. Compared to their initial oil reserves, these fields currently have an average recovery rate of approximately 15% to 35%. Therefore, they offer consistently considerable production potential.

[0003] Typically, the extraction of crude oil contained in sediments is carried out in multiple stages.

[0004] Production initially comes from the natural energy of fluids and the self-decompression of rocks. By 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 phase, it is necessary to use techniques to increase recovery rates by maintaining oilfield pressure.

[0005] The most common method involves injecting water into the deposit through injection wells specifically designed for this purpose. This is called secondary recovery. This second stage stops when the water / oil ratio becomes too high, meaning when the amount of water in the mixture produced by the production wells is too high. Therefore, this secondary recovery allows for an additional recovery rate of 10 to 20%.

[0006] Other technologies that can be used are called enhanced oil recovery (EOR). Their goal is to recover 10 to 35% more oil than the initial amount. Various thermal or non-thermal recovery technologies are called enhanced oil recovery, such as so-called electro-, miscible, steam, or even chemical technologies, for enhancing the recovery of remaining oil (see "Oil & Gas Science and Technology" – IFP journal, Vol. 63 (2008) No. 1, pp. 9–19).

[0007] The term "petroleum" should be understood to refer to any type of petroleum, i.e., light oil, heavy oil, or even bituminous oil. Petroleum is generally the result of the natural transformation of organic matter and consists of a mixture of hydrocarbons. In the prior art or the description of this invention, the terms "petroleum" and "oil" are used to refer to the same substance, except when referring to compositions of emulsions or dispersions.

[0008] Water sweeping efficiency is typically improved by adding water-soluble polymers. The anticipated and proven benefits of using polymers, through "viscosification" of the injected water, are increased sweep and reduced viscosity differences between fluids to control their mobility ratio in the oilfield, thereby enabling rapid and efficient hydrocarbon recovery. These polymers increase the viscosity of the water.

[0009] Those skilled in the art know that synthesized water-soluble polymers (particularly polymers based on 2-acrylamido-2-methylpropanesulfonic acid (ATBS)) are highly effective at increasing the viscosity of aqueous solutions and for improving oil recovery. In fact, ATBS-based polymers are known to withstand divalent salts and high temperatures.

[0010] Besides increasing the viscosity of water, the polymer used must also possess good filterability. Polymers with poor filterability tend to clog formations, slowing down or even inhibiting hydrocarbon (oil and / or natural gas) production. However, filterability decreases as the molecular weight of the polymer increases. Therefore, there is a delicate trade-off between molecular weight and filterability.

[0011] Polymers added to injection water typically undergo a long residence time (months to years) in the deposit between the injection and production wells. During this time, they may undergo thermal degradation, leading to increased hydrolysis rates through the conversion of acrylamide or ATBS units into acrylates, or chemical degradation, resulting in chain breakage (molecular weight reduction) due to free radical attack. In both cases, these mechanisms generally lead to a decrease in viscosity, thus reducing the efficiency of the injected polymer aqueous solution in reaching the subsurface formation. Therefore, there is great interest in developing polymers that are more resistant to these processes involved in any enhanced hydrocarbon recovery project (oil and / or gas). Summary of the Invention

[0012] The applicant has discovered and developed a method for enhancing hydrocarbon (oil and / or natural gas) recovery using a water-soluble polymer containing sodium 2-acrylamido-2-methylpropanesulfonate (ATBS.Na) in crystalline form as a monomer. The polymer has improved properties, particularly in terms of filterability and chemical and thermal stability.

[0013] The improved properties of injection fluids containing polymers obtained from crystalline ATBS.Na help reduce the amount of desired products, thereby reducing total water consumption and greenhouse gas (e.g., CO2) emissions.

[0014] More specifically, the present invention relates to a method for enhancing hydrocarbon (oil and / or natural gas) recovery, comprising the following steps:

[0015] a) Prepare an injection fluid containing at least one water-soluble polymer of 2-acrylamido-2-methylpropanesulfonic acid (ATBS) using water or brine;

[0016] Prior to polymerization, ATBS exists in crystalline sodium ATBS form, and its X-ray powder diffraction pattern includes peaks at the following locations: 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°; 47.6° (2θ angle);

[0017] b) Inject the injection fluid into the underground formation;

[0018] c) Using injected fluid to penetrate underground strata;

[0019] d) Harvest aqueous hydrocarbon mixtures (mixtures containing water and hydrocarbons).

[0020] Surprisingly, the use of at least one water-soluble polymer obtained from crystalline sodium ATBS salt enables effective treatment of subsurface formations. In fact, the use of crystalline sodium ATBS salt in the preparation of the water-soluble polymer imparts unique properties to the polymer, enabling improved hydrocarbon recovery.

[0021] Description of the present invention

[0022] The term "polymer" should be understood as referring to a homopolymer or copolymer. The term "copolymer" should be understood as referring to a polymer obtained from at least two different monomers. Therefore, it can 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.

[0023] The term "hydrophilic monomer" should be understood as referring to an octanol-water partition coefficient K equal to or less than 1. ow The monomer, where the partition coefficient K ow It was determined at 25°C, in a 1 / 1 volume ratio octanol-water mixture, and at a pH of 6 to 8.

[0024] The term "crystal" or "crystalline form" refers to a solid material whose components (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a lattice that extends in all directions. It does not include amorphous solids.

[0025] The term "hydrophobic monomer" should be understood as referring to an octanol-water partition coefficient K greater than 1. ow The monomer, where the partition coefficient K ow It was determined at 25°C, in a 1 / 1 volume ratio octanol-water mixture, and at a pH of 6 to 8.

[0026] Octyl alcohol-water partition coefficient K ow This represents the concentration ratio (g / L) of the monomer between the octanol phase and the aqueous phase. Its definition is as follows:

[0027] [Calculation 1]

[0028]

[0029] By definition, a water-soluble polymer is a polymer that, when dissolved in 50 g / L at 25°C... -1 When the polymer is stirred and dissolved in water at a concentration of 1, a polymer is obtained that produces an aqueous solution free of insoluble particles.

[0030] "X and / or Y" should be understood as referring to "X", or "Y", or "X and Y".

[0031] This invention also includes all possible combinations of the various disclosed embodiments, whether they are preferred embodiments or given as examples. Furthermore, when numerical ranges are specified, limiting values ​​are included within these ranges. This disclosure also includes all combinations between the limiting values ​​of these numerical ranges. For example, the numerical range "1-20, preferably 5-15" means the ranges "1-5", "1-15", "5-20", and "15-20", as well as the disclosed values ​​1, 5, 15, and 20.

[0032] ATBS sodium salt in crystalline form

[0033] The crystalline form of sodium ATBS has an X-ray powder diffraction pattern containing peaks at the following positions: 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°; 47.6°. The uncertainty of these peaks is typically + / - 0.1°.

[0034] X-ray crystallography, radiation crystallography, or X-ray diffraction is an analytical technique used to study the structure of crystalline materials at the atomic scale. It is based on the physical phenomenon of X-ray diffraction. A diffractometer with a copper source can be used.

[0035] Powders formed from a specific crystalline phase always exhibit diffraction peaks in the same direction. This diffraction pattern thus forms the true characteristics of the crystalline phase. Therefore, the properties of each crystalline phase in a mixture or pure product can be determined.

[0036] This characteristic is specific to each type of organic or inorganic compound and is in the form of a series of peaks located at the 2θ (2-θ) angle.

[0037] This technique is used to characterize substances, especially the different crystalline forms that the same chemical molecule may exist in.

[0038] The crystalline form of sodium ATBS has a Fourier transform infrared spectrum including a peak at the following position: 3576 cm⁻¹ -1 3485cm -1 3310cm -1 3079cm -1 2975cm -1 1658cm -1 1629cm -1 1543cm -1 1403cm -1 1321cm -1 1301cm -1 1205cm -1 1187cm -1 1163cm -1 1046cm -1 980cm -1 629cm -1 The uncertainty of these peaks is typically around 8 cm⁻¹. -1 .

[0039] Infrared measurements were performed via Fourier transform, for example using a PerkinElmer Spectrum 100 spectrometer equipped with a single-reflection ATR polarization accessory, with an accuracy of 8 cm⁻¹. -1 .

[0040] Fourier transform infrared spectroscopy is the analysis of vibrations that emit, absorb, or scatter molecules. This technique is sensitive to so-called short interactions (the effect of the unit grid on bonds). In most cases, the Fourier transform infrared spectra of different crystal systems are significantly different. Therefore, Fourier transform infrared spectra reveal details of the crystal structure of compounds.

[0041] Typically, unless otherwise specified, X-ray diffraction patterns and infrared spectra are obtained at 20°C and 1 atmosphere (101,325 Pa).

[0042] The minimum ignition energy of crystalline sodium ATBS is greater than 500 mJ, and preferably greater than 1000 mJ (1 mJ = 10⁻⁶ mJ). -3 joule).

[0043] Minimum ignition energy represents the minimum energy that must be supplied to the product (compound) to ignite it. This energy can be electrical or thermal. Minimum ignition energy is a crucial piece of information when considering the explosion risk during product handling (transfer, storage, reaction, shaping, etc.).

[0044] The minimum ignition energy depends on the properties of the powder (composition) and its macromolecular structure (particle size, crystal form, specific surface area).

[0045] In the case of solids, this energy is the minimum energy required for an electric spark to ignite a cloud of dust. The higher the minimum ignition energy, the lower the risk during the use, handling, or storage of the solid.

[0046] Minimum ignition energy is measured according to standard NF EN 13821.

[0047] Four thermal phenomena were observed in the crystalline form of sodium ATBS using differential scanning calorimetry at 49.8 °C, 144.8 °C, 169.8 °C, and 254.3 °C. The uncertainty associated with monitoring these phenomena was typically around 10 °C, favorably 5 °C or less.

[0048] Thermal phenomena are measured using differential scanning calorimetry (DSC). This technique utilizes measurements of thermal changes associated with the thermal denaturation of the compound when heated at a constant rate (e.g., a heating rate of 10 °C / min). A method for producing sodium ATBS in crystalline form.

[0049] The method for producing crystalline sodium ATBS includes at least the following sequential steps:

[0050] 1) Mix ATBS with an aqueous solution SA1 and at least one sodium salt base, and mix for at least 1 minute to form an aqueous solution or aqueous suspension SA2;

[0051] 2) Distill the aqueous solution or aqueous suspension SA2 at a pressure of 700 mbar or lower to form suspension S1;

[0052] 3) Perform solid-liquid separation on the suspension S1 and separate the crystals in the form of composition C1 of the suspension S1 obtained at the end of step 2).

[0053] The obtained crystals are sodium ATBS in crystalline form.

[0054] In step 1), "sodium salt base" should be understood to refer to at least one inorganic sodium salt. Alkali, such as sodium hydroxide, sodium carbonate, sodium bicarbonate or mixtures thereof.

[0055] The temperature and mixing time in step 1) can be varied specifically as a function of the ATBS concentration. Those skilled in the art know how to adjust the temperature variation and mixing time to optimize crystal formation.

[0056] The method for producing crystalline ATBS.Na can be carried out on ATBS in any form (e.g., needle-like or hydrated).

[0057] This production method can be carried out on ATBS of any purity.

[0058] Therefore, this method can be carried out downstream of any type of ATBS production process. It can also be used with ATBS in any form already obtained (i.e., amorphous or crystalline).

[0059] Step 1) of the method for producing crystalline ATBS.Na:

[0060] ATBS is produced using the production methods described above (acrylonitrile, fuming sulfuric acid, and isobutylene). ATBS can be in the form of a fine powder or shaped in a controlled manner by methods such as pressing, granulation, or extrusion.

[0061] ATBS can be added to the aqueous solution SA1 before, after, or in parallel with the addition of sodium salt alkali, preferably in parallel. Preferably, the aqueous solution is water.

[0062] Sodium salts can be added as an aqueous solution (SA1). In this case, the sodium salt solution can be partially or entirely aqueous solution (SA1).

[0063] Advantageously, the concentration of sodium ATBS in the aqueous solution or aqueous suspension SA2 is 1% by weight to saturation, preferably 10% by weight to saturation, more preferably 20% by weight to saturation, more preferably 30% by weight to saturation, more preferably 40% by weight to saturation, and even more preferably 50% by weight to saturation relative to the weight of the aqueous solution or aqueous suspension SA2.

[0064] ATBS and sodium hydroxide can be added all at once or in multiple stages. It is preferable to add them all at once.

[0065] When they are added in multiple stages, ATBS and sodium salts are added in batches.

[0066] When ATBS and sodium salt are added in batches, there is no limit to the number of batches, but it is advantageous to have at least two batches, preferably at least three batches.

[0067] There are no restrictions on the order in which ATBS and sodium salt are added. They can be added simultaneously (i.e., in parallel), one after another (ATBS first, then sodium salt, and vice versa), or alternately (the first part of ATBS is added, then the first part of sodium salt, then the second part of ATBS, then the second part of sodium salt, and so on); they are preferably added simultaneously.

[0068] When they are added one after another or alternately, the second compound (whether it is ATBS or sodium salt base) can be added before the first compound has been added.

[0069] The first portion F1 of ATBS advantageously represents at least 1 mol%, preferably at least 5 mol%, more preferably at least 10 mol%, even more preferably at least 15 mol%, and even more preferably at least 20 mol% of the total amount of ATBS present in the aqueous solution or aqueous suspension SA2.

[0070] The second part of ATBS, F2, advantageously represents at least 1 mol%, preferably at least 5 mol%, more preferably at least 10 mol%, even more preferably at least 15 mol%, and even more preferably at least 20 mol% of the total amount of ATBS present in the aqueous solution or aqueous suspension SA2.

[0071] The third part F3 of ATBS advantageously represents at least 1 mol%, preferably at least 5 mol%, more preferably at least 10 mol%, even more preferably at least 15 mol%, and even more preferably at least 20 mol% of the total amount of ATBS present in the aqueous solution or aqueous suspension SA2.

[0072] In one particular implementation, the method is carried out continuously, in which case ATBS and sodium salt base are added continuously.

[0073] 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.

[0074] The mixing (ATBS + sodium salt alkali) in step 1) is advantageously 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.

[0075] In one particular implementation, the aqueous solution or aqueous suspension SA2 may contain one or more organic solvents.

[0076] In some implementations, the aqueous solution SA1 may contain one or more organic solvents.

[0077] The amount of organic solvent can vary as a function of temperature and the amount of ATBS or sodium salt. This amount is not limited, as long as it does not prevent the acquisition of crystalline ATBS sodium salt. Those skilled in the art know how to determine this limitation; it is a routine task. Typically, aqueous solutions or aqueous suspensions of SA2 contain more water (by volume) than the organic solvent.

[0078] One or more organic solvents are advantageously selected from the following compounds:

[0079] - Organic acids, preferably carboxylic acids containing 1 to 8 carbon atoms;

[0080] -Amide, which advantageously contains 1 to 8 carbon atoms;

[0081] - Alcohols, which advantageously contain 1 to 8 carbon atoms;

[0082] - Ketones, which advantageously contain 3 to 8 carbon atoms;

[0083] - ethers, which advantageously contain 2 to 8 carbon atoms;

[0084] -Esters, which advantageously contain 2 to 8 carbon atoms;

[0085] -Alkanes, which advantageously contain 4 to 8 carbon atoms, preferably 5 to 6 carbon atoms;

[0086] - Halohydrocarbon compounds, which advantageously contain 1 to 8 carbon atoms;

[0087] - Nitriles, which advantageously contain 1 to 8 carbon atoms; or

[0088] - Their mixture.

[0089] When an organic solvent is used in this invention, the temperature can be adjusted so that the solvent + water mixture remains in liquid form.

[0090] These compounds can be straight-chain or branched. They can be saturated or contain unsaturated bonds. Unsaturated bonds are equivalent to double or triple bonds (e.g., C=C or C≡C).

[0091] The organic solvent is preferably selected from acrylonitrile, isopropanol, acrylic acid, acetic acid, or mixtures thereof. Acrylonitrile is the preferred organic solvent.

[0092] At the temperatures used in steps 2) and 3), the organic solvent is typically in liquid form. Furthermore, it is advantageously partially miscible with water, and preferably completely miscible with water.

[0093] If necessary, organic solvents can be used to dissolve any impurities or byproducts present with ATBS used to form an aqueous solution or suspension of SA2. However, ATBS is not necessarily soluble in solvents.

[0094] In a preferred embodiment of the invention, the aqueous solution or aqueous suspension SA2 does not contain organic solvents.

[0095] In a preferred embodiment of the invention, the aqueous solution SA1 does not contain organic solvents.

[0096] The allowed time for mixing the aqueous solutions SA1 and ATBS is advantageously at least 1 minute, preferably 1 minute to 600 minutes, more preferably 5 minutes to 400 minutes, and even more preferably 10 minutes to 240 minutes.

[0097] The compound in step 1) can be mixed using a variety of techniques. Examples include, but are not limited to, reactors with stirrers, loop reactors, static mixers, microreactors, piston reactors, stirred filter dryers (e.g., Nutsche's), paddle mixers, double cone mixers, plough mixers, and disc mixers.

[0098] The pH in step 1) is advantageously controlled to be 6 to 14, preferably 8 to 14, more preferably 10 to 14, even more preferably 12 to 14, and even more preferably 13 to 14.

[0099] The amount of ATBS.Na in the aqueous solution SA2 or the 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 the aqueous suspension SA2.

[0100] Step 2) of the method for producing crystalline sodium ATBS:

[0101] Distillation of the aqueous solution or aqueous suspension SA2 is carried out at a pressure of 700 mbar or lower. It is usually carried out in a vacuum distillation apparatus (which is typically an evaporator). Therefore, it is also referred to as "vacuum distillation" in this document.

[0102] When an aqueous solution or aqueous suspension of SA2 is distilled, typically by passing it through an evaporator, sodium ATBS crystals begin to form. Sodium ATBS particles coexist in the aqueous solution or aqueous suspension of SA2.

[0103] An evaporator can be used to distill the aqueous solution or aqueous suspension SA2. This evaporator can be a falling film evaporator, a rising film evaporator, a scraped thin-film evaporator, a short-path evaporator, a forced circulation evaporator, a spiral tube evaporator, or a flash evaporator. It can also be a continuously stirred reactor. Preferably, distillation is carried out in a scraped thin-film evaporator, a short-path evaporator, or a forced circulation evaporator. Even more preferably, distillation is carried out in a scraped thin-film evaporator.

[0104] Typically, an evaporator is a device that includes an inlet for the solution to be treated (an aqueous solution or an aqueous suspension SA2), an outlet for discharging the distilled solvent (water and any organic solvent), and an outlet for discharging the suspension S1.

[0105] The residence time (in other words, distillation time) of the aqueous solution or aqueous suspension SA2 in a distillation apparatus (advantageously under vacuum) (which is advantageously an evaporator) at a pressure of 700 mbar or lower is advantageously from 1 second to 600 seconds, preferably from 3 seconds to 300 seconds, and more preferably from 30 seconds to 100 seconds. This residence time corresponds to the time required to perform step 2), i.e., the time required to prepare suspension S1 by distilling the aqueous solution or aqueous suspension SA2. In other words, when using an evaporator, this time is the residence time of ATBS (and / or its sodium salt in crystalline form) between the inlet and outlet of the apparatus. This residence time depends on the amounts of water (and any organic solvent), ATBS.Na, and sodium salt present in the aqueous solution or aqueous suspension SA2. Those skilled in the art know how to adjust the residence time according to the amounts of the components of the aqueous solution or aqueous suspension SA2 to obtain ATBS.Na in crystalline form.

[0106] Distillation can be carried out in a vertical or horizontal evaporator. Preferably, it is carried out in a vertical evaporator.

[0107] The aqueous solution or aqueous suspension SA2 can be circulated in parallel or countercurrent with the steam generated by evaporation. Preferably, it is circulated countercurrently with the steam in the distillation apparatus. In other words, it is preferable to introduce the aqueous solution or aqueous suspension SA2 into the distillation apparatus (advantageously the evaporator) in parallel or countercurrent with the distillation solvent.

[0108] Before obtaining suspension S1, the aqueous solution or aqueous suspension SA2 can be circulated in one or more evaporators connected in series. Preferably, it is circulated in a single evaporator.

[0109] The pressure during distillation is advantageously between 1 and 700 mbar absolute (1 mbar = 100 Pa). It is preferably less than 700 mbar absolute, more preferably less than 600 mbar absolute, more preferably less than 500 mbar absolute, more preferably less than 400 mbar absolute, more preferably less than 300 mbar absolute, more preferably less than 200 mbar absolute, more preferably less than 100 mbar absolute, and even more preferably less than 50 mbar absolute, and advantageously greater than 1 mbar absolute. Absolute pressure corresponds to pressure relative to zero pressure (vacuum).

[0110] Typically, the pressure during the distillation process is preferably 10 to 700 mbar, more preferably 20 to 700 mbar, more preferably 40 to 700 mbar, even more preferably 50 to 600 mbar, even more preferably 50 to 500 mbar, even more preferably 50 to 400 mbar, even more preferably 50 to 300 mbar, even more preferably 100 to 700 mbar, even more preferably 200 to 700 mbar, even more preferably 500 to 700 mbar, even more preferably 40 to 100 mbar.

[0111] In one particular embodiment, step 2) includes step 2') (optional), which helps the solvent evaporate. Step 2') involves raising the temperature of the aqueous solution or aqueous suspension SA2, in other words, performing the distillation according to step 2') under heating.

[0112] In some embodiments, in step 2), the aqueous solution or aqueous suspension SA2 is advantageously heated at a temperature of 5°C to 95°C, preferably more than 10°C to 60°C, and more preferably more than 20°C to 40°C.

[0113] Heating during the distillation process can be achieved through a variety of techniques. Examples include, but are not limited to, heating with steam, hot water, electricity, by vapor compression, or practically using a heat pump. Therefore, the distillation apparatus can be double-walled, with the heat transfer fluid circulating between the two walls.

[0114] The aqueous solution or aqueous suspension SA2 is advantageously 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.

[0115] When heating the aqueous solution or aqueous suspension SA2, the temperature is advantageously greater than the temperature in step 1).

[0116] The temperature of the aqueous solution or aqueous suspension SA2 is advantageously increased at a rate 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.

[0117] In some embodiments, the temperature of the aqueous solution or aqueous suspension SA2 is advantageously increased at a rate 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.

[0118] Throughout the process, the temperature increase may not be constant. For example, an aqueous solution or aqueous suspension of SA2 may be heated at a rate of 5°C per hour for the first 3 hours, and then at a rate of 10°C per hour until the final temperature is reached.

[0119] According to another specific embodiment of the invention, step 2) may include step 2”) (optionally) (which follows or replaces step 2’) and step 2”) contributes to increasing the yield and profitability of the method of the invention by accelerating the crystallization of ATBS into its crystalline form as a sodium salt. Step 2”) involves lowering the temperature of the aqueous solution or aqueous suspension of SA2.

[0120] The aqueous solution or aqueous suspension SA2 is advantageously cooled to a temperature of 5°C to less than 95°C, preferably 10°C to less than 60°C, more preferably 20°C to less than 40°C, and even more preferably 10°C to 40°C.

[0121] In some implementations, step 2) also includes a cooling step.

[0122] The cooling step is advantageously carried out at a temperature of 5°C to 95°C, preferably more than 10°C to 60°C, and more preferably more than 10°C to 40°C.

[0123] In some embodiments, the temperature of the cooling step is increased at a rate 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.

[0124] In some implementations, the temperature of the cooling step is advantageously lower than the heating temperature of step 2) and / or step 1).

[0125] In some embodiments, a cooling step is performed on the aqueous solution or aqueous suspension SA2 and / or concentrated aqueous solution or aqueous suspension SA2 and / or suspension S1.

[0126] When cooling the aqueous solution or aqueous suspension SA2 (step 2"), the temperature is advantageously lower than the temperature of step 2) and optionally 2').

[0127] According to a preferred embodiment, the temperature of step 2) is equal to or lower than the temperature of step 1).

[0128] In some implementations, no organic solvent or aqueous solution is added in step 2” to obtain ATBS.Na crystals.

[0129] The temperature of the aqueous solution or aqueous suspension SA2 is advantageously reduced at a rate 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.

[0130] Throughout the process, the temperature reduction may not be constant. For example, an aqueous solution or aqueous suspension of SA2 may be cooled at a rate of 5°C per hour for the first 3 hours, and then at a rate of 8°C per hour until the final temperature is reached.

[0131] When the aqueous solution or aqueous suspension SA2 is cooled, crystals and suspension S1 in the form of sodium ATBS are obtained.

[0132] In one particular implementation, previously obtained sodium ATBS salt crystals may be added during this step to alter the composition of suspension S1. This process, known as seed crystallization, allows for better control over the crystallization temperature, crystal particle size, particle size distribution, purity of the final product, and possible yield. Sodium ATBS crystals advantageously possess X-ray powder diffraction patterns containing peaks at the following locations: 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°; 47.6° 2-θ angle (+ / -0.1°).

[0133] According to a particular embodiment of the invention, the solvent distilled in step 2) may be partially or completely recycled to form the aqueous solution or aqueous suspension SA2 of step 1). In other words, the distilled solvent is advantageously recycled at least partially to the aqueous solution or aqueous suspension SA2.

[0134] According to another specific embodiment of the invention, in optional step 4) (with or without a pretreatment step), the distilled solvent may be partially or completely recycled, typically for washing the ATBS sodium salt crystals obtained after step 3) of solid-liquid separation.

[0135] The obtained suspension S1 advantageously contains 30 to 90% by weight of crystalline ATBS.Na relative to the total weight of the suspension S1, preferably 50 to 90% by weight, more preferably 30 to 80% by weight, and most preferably 50 to 60% by weight of crystalline ATBS.Na relative to the total weight of the suspension S1.

[0136] During step 2), the pH is advantageously greater than 10, preferably greater than 11, more preferably greater than 12, and even more preferably 13 to 14.

[0137] Step 3) of the method for producing crystalline sodium ATBS:

[0138] The ATBS.Na crystals contained in the suspension S1 obtained at the end of step 2) are separated in the solid-liquid separation step and are in the form of composition C1.

[0139] Solid-liquid separation can be performed using a variety of techniques. Examples include, but are not limited to, centrifuges, decanters, filter presses, stirred filters, belt filters, disc filters, or drum filters. Centrifuges are preferred for solid-liquid separation. Solid-liquid separation can also be achieved through gravity sedimentation.

[0140] Step 3) is advantageously carried out at a temperature of -20°C to 40°C, preferably -5°C to 30°C.

[0141] After step 3) of solid-liquid separation, it is preferable not to dry the ATBS sodium salt crystals.

[0142] The ATBS sodium salt crystal content of the isolated composition C1 is advantageously 40 to 99% by weight, preferably 60 to 99% by weight, more preferably 60 to 98% by weight, and even more preferably 80 to 99% by weight relative to the weight of composition C1. The remainder of composition C1 may be water and / or soluble ATBS sodium salt, as well as the sodium salt base that may have been introduced in step 1).

[0143] At the end of step 3), the crystals were characterized as sodium ATBS crystals.

[0144] In one particular embodiment, all or part of the liquid phase obtained after solid-liquid separation is used for the aqueous solution or aqueous suspension SA2 of step 1).

[0145] During step 4), the pH is advantageously controlled to be 6 to 14, preferably 8 to 14, more preferably 10 to 14, even more preferably 12 to 14, and even more preferably 13 to 14.

[0146] Step 4 of the method for producing crystalline ATBS.Na:

[0147] In optional step 4), the composition C1 containing ATBS.Na crystals obtained at the end of step 3) is washed with a washing solution.

[0148] The washing solution can be water, an aqueous solution of sodium salt (which may be saturated or unsaturated), or a solution of sodium ATBS (advantageously in crystalline form ATBS.Na) (which may be saturated or unsaturated), and it is preferably a saturated solution of ATBS.Na.

[0149] Examples of sodium salt alkaline solutions include solutions of sodium hydroxide, sodium carbonate, sodium bicarbonate, or mixtures thereof.

[0150] The washing solution may contain one or more organic solvents.

[0151] The amount of organic solvent can vary as a function of temperature and the amount of ATBS sodium salt or sodium salt.

[0152] Advantageously, the washing solution does not contain organic solvents.

[0153] As indicated in step 1), the organic solvent is advantageously selected from organic acids, amides, alcohols, ketones, ethers, esters, alkanes, halogenated hydrocarbons, 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.

[0154] In one particular embodiment, composition C1 obtained at the end of step 3) is washed by spraying a washing solution onto the composition C1.

[0155] In one particular embodiment, the composition C1 is washed by suspending the composition C1 obtained at the end of step 3) in a washing solution.

[0156] The weight ratio of the aqueous washing solution to the composition C1 obtained at the end of step 3) is advantageously 0.05:1 to 10:1, more preferably 0.1:1 to 5:1.

[0157] 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 that the ATBS sodium salt crystals do not dissolve.

[0158] The ATBS sodium salt crystals obtained at the end of this optional step 4) can be separated from the washing solution in the form of composition C2 by a solid-liquid separation step.

[0159] Solid-liquid separation can be performed using a variety of techniques. Examples include, but are not limited to, vertical or horizontal centrifuges, decanters, filter presses, belt filters, disc filters, push-button filters, or drum filters. Solid-liquid separation can also be achieved through gravity settling.

[0160] In one particular implementation, all or part of the recovered washing solution can be reused in step 4 (with or without a pretreatment step).

[0161] In one particular implementation, all or part of the recovered washing solution may be used in step 1 (with or without a pretreatment step) as an aqueous solution or aqueous suspension SA2.

[0162] The pH of the washing solution in step 5 is advantageously controlled to be 6 to 14, preferably 8 to 14.

[0163] Step 5 of the method for producing crystalline ATBS.Na:

[0164] In 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.

[0165] The drying step can be performed using a variety of techniques. Examples include, but are not limited to, the use of all convection, conduction, or radiation drying techniques (fluidized bed dryers, through-bed dryers, conveyor belt dryers, microwaves, heated stirred filters, high-frequency radiation, infrared radiation, and spraying).

[0166] The drying process can be carried out under atmospheric pressure or vacuum.

[0167] The drying process can be carried out discontinuously (intermittent drying) or continuously.

[0168] Other steps in the method for producing crystalline ATBS.Na:

[0169] During the production process, i.e., during steps 1) to 5), and in any step, at least one polymerization inhibitor may be introduced to prevent possible polymerization of ATBS or its salts. The polymerization inhibitor may be selected in a non-limiting manner from hydroquinone, p-methoxyphenol, phenothiazine, 2,2,6,6-tetramethyl(piperidin-1-yl)oxy, 4-hydroxy-2,2,6,6-tetramethyl(piperidin-1-yl)oxy, phenylenediamine derivatives, or mixtures thereof.

[0170] The preferred polymerization inhibitors are p-methoxyphenol or 4-hydroxy-2,2,6,6-tetramethyl(piperidin-1-yl)oxy.

[0171] The amount of the polymerization inhibitor introduced is advantageously 0.001% to 5% by weight, more preferably 0.01% to 1% by weight, relative to the amount of ATBS introduced in step 1).

[0172] The polymerization inhibitor may be introduced during any one or more steps of the method. Preferably, an additional amount of the polymerization inhibitor is introduced during step 1). More preferably, the polymerization inhibitor is part of the aqueous solution or aqueous suspension SA1 introduced in step 1).

[0173] The production process (steps 1 to 5) can be carried out continuously or intermittently (intermittent production).

[0174] Composition of water-soluble polymers

[0175] The water-soluble polymer is obtained from crystalline ATBS.Na and advantageously 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. Therefore, it can be a polymer or homopolymer of a variety of different monomers.

[0176] Advantageously, one or more hydrophilic nonionic monomers that can be used in the present invention are particularly selected from the group comprising: water-soluble vinyl monomers, such as acrylamide, methacrylamide, N-alkylacrylamide, N-alkylmethylacrylamide, N,N-dialkylacrylamide (e.g., N,N-dimethylacrylamide or N,N-diethylacrylamide), N,N-dialkylmethylacrylamide, alkoxylated esters of acrylic acid, N-vinylpyrrolidone, N-hydroxymethyl (meth)acrylamide, N-vinylcaprolactam, N-vinylformamide (N... VF), N-vinylacetamide, N-vinylimidazolium, N-vinylsuccinimide, acrylamide (ACMO), glycidyl methacrylate, vinyl acetate, glyceryl methacrylate, diacetone acrylamide, methacrylic anhydride, acrylonitrile, maleic anhydride, itacamide, hydroxyalkyl (meth)acrylate, thioalkyl (meth)acrylate, isoprene alcohol and its alkoxylated derivatives, hydroxyethyl (meth)acrylate and its alkoxylated derivatives, hydroxypropyl acrylate and its alkoxylated derivatives, and mixtures thereof. In the nonionic monomers, the alkyl group is advantageously C1-C5, more advantageously C1-C3. They are preferably straight-chain alkyl groups. Preferably, the hydrophilic nonionic monomer is acrylamide.

[0177] The water-soluble polymer advantageously comprises 0 to 99 mol%, preferably 5 to 99 mol%, more preferably 25 to 99 mol%, of one or more nonionic monomers.

[0178] Advantageously, in addition to the crystalline form of ATBS.Na, one or more hydrophilic anionic monomers that can be used in this invention can be selected from a large group. These monomers may have vinyl functional groups (advantageously acrylic acid, maleic acid, fumaric acid, malonic acid, itaconic acid, or allyl) and contain carboxyl, phosphonate, phosphate, sulfate, or sulfonate groups, or another anionic charged group. Examples of suitable monomers include acrylic acid; methacrylic acid; dimethacrylic acid; itaconic acid; C1-C3 half-esters of itaconic acid; acryloyl chloride; crotonic acid; maleic acid; fumaric acid; 3-acrylamido-3-methylbutyric acid; strong acid monomers having, for example, sulfonic or phosphonic functional groups, such as vinyl sulfonic acid, vinyl phosphonic acid, allyl sulfonic acid, methyl allyl sulfonic acid, 2-methylenepropane-1,3-disulfonic acid, 2-sulfoethyl methacrylate, sulfopropyl methacrylate, sulfopropyl acrylate, allyl phosphonic acid, ethylene glycol methacrylate phosphate, 2-acrylamido-2-methylpropanesulfonic acid (ATBS), 2-acrylamido-2-methylpropanedisulfonic acid, 3-allyloxy-2-hydroxypropanesulfonic acid, diethyl allyl phosphonate, carboxyethyl acrylate; water-soluble salts of these monomers, such as their alkali metal salts (different from the crystalline form of ATBS.Na), alkaline earth metal salts, or ammonium salts; and mixtures thereof. Preferably, one or more hydrophilic anionic monomers are acrylic acid and / or its salts.

[0179] The water-soluble polymer advantageously contains 1 to 100 mol%, preferably 5 to 60 mol%, more preferably 10 to 50 mol%, of one or more anionic hydrophilic monomers (different from the crystalline form of ATBS.Na), these percentages including monomers corresponding to the crystalline form of sodium ATBS.

[0180] In one particular implementation, one or more anionic hydrophilic monomers other than ATBS.Na in crystalline form can form salts.

[0181] The term "salt formation" refers to the formation of -R groups in anionic monomers. a In the (=O)-OH type (R represents P, S, or C), at least one acidic functional group has its proton replaced by a metal or ammonium cation to form -R. a (=O)-OX type (X is a metal cation or an organic cation) salt. In other words, the non-salt-forming form corresponds to the acid form of the monomer, for example, R in the case of a carboxylic acid functional group. b -C(=O)-OH, while the salt-forming form of the monomer corresponds to R. b -C(=O)-OX + Form, X +Corresponding to basic cations or organic cations. The acid functional groups of branched water-soluble polymers can partially or completely form salts. The salt form advantageously corresponds to salts of alkali metals (Li, Na, K, etc.), alkaline earth metals (Ca, Mg, etc.), or ammonium (e.g., ammonium ions or tertiary ammonium). The preferred salt is a sodium salt.

[0182] Salt formation can occur before, during, or after polymerization.

[0183] In one particular embodiment, the water-soluble polymer advantageously 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 salt-forming form.

[0184] Advantageously, one or more hydrophilic cationic monomers used in this invention are selected from monomers derived from vinyl units (advantageously acrylamide, acrylic acid, allyl, or maleic acid) having phosphonium or quaternary ammonium functional groups. Reference may be made, particularly and non-limitingly, to diallyl dialkylammonium salts, such as diallyl dimethylammonium chloride (DADMAC); acidified or quaternized salts of dialkylaminoalkyl (meth)acrylamides, such as methacrylamidopropyltrimethylammonium chloride (MAPTAC) and acrylamidopropyltrimethylammonium chloride (APTAC); acidified or quaternized salts of dialkylaminoalkyl acrylates, such as quaternized or salted dimethylaminoethyl acrylate (DMAEA); and acidified or quaternized dialkylaminoalkyl methacrylates. Salts, such as quaternized or salted dimethylaminoethyl methacrylate (DMAEMA); acidified or quaternized salts of N,N-dimethylallylamine; acidified or quaternized salts of diallylmethylamine; acidified or quaternized salts of diallylamine; ethyleneamines obtained by hydrolysis (basic or acidic) of the amide group -N(R2)-CO-R1 (where R1 and R2 are independently hydrogen atoms or alkylated chains of 1 to 6 carbons), such as ethyleneamines obtained by hydrolysis of vinylformamide; ethyleneamines obtained by Hoffmann degradation; and mixtures thereof. Advantageously, the alkyl group is C1-C7, preferably C1-C3, and can be a straight chain, cyclic, saturated or unsaturated chain. Quaternized dimethylaminoethyl methacrylate is preferred.

[0185] Those skilled in the art know how to prepare quaternized monomers, for example, using RX-type (where R is an alkyl group and X is a halogen or sulfate) quaternizing agents.

[0186] The term "quaternizing agent" refers to a molecule capable of alkylating tertiary amines.

[0187] The quaternizing agent can be selected from dialkyl sulfates containing 1 to 6 carbon atoms or haloalkanes containing 1 to 6 carbon atoms. Preferably, the quaternizing agent is selected from chloromethane, benzyl chloride, dimethyl sulfate, or diethyl sulfate. Furthermore, the present invention also includes DADMAC, APTAC, and MAPTAC monomers, whose counterions are sulfate, fluoride, bromide, or iodide ions instead of chloride ions.

[0188] The water-soluble polymer advantageously contains 0 to 20 mol%, preferably 0 to 6 mol%, of one or more cationic monomers.

[0189] Advantageously, one or more zwitterionic hydrophilic monomers may be derivatives of vinyl units (advantageously acrylamide, acrylic acid, allyl or maleic acid), which have quaternary ammonium or ammonium functional groups and carboxylic acid (or carboxyl group), sulfonic acid (or sulfonate group) or phosphoric acid (or phosphate group) functional groups. Dimethylaminoethyl acrylate derivatives, such as 2-((2-(acryloyloxy)ethyl)dimethylammonium)dimethylammonium)ethane-1-sulfonate, 3-((2-(acryloyloxy)ethyl)dimethylammonium)propane-1-sulfonate, 4-((2-(acryloyloxy)ethyl)dimethylammonium)butane-1-sulfonate, [2-(acryloyloxy)ethyl](dimethylammonium)acetate, and dimethylaminoethyl methacrylate derivatives, such as 2-((2-(methacryloyloxy)ethyl)dimethylamino)ethane-1-sulfonate, 3-((2-(methacryloyloxy)ethyl)dimethylammonium)propane-1-sulfonate, 4-((2-(methacryloyloxy)ethyl)dimethylammonium)butane-1-sulfonate, [2-(methacryloyloxy)ethyl]( Dimethylaminopropylacrylamide derivatives, such as 2-((3-acrylamidopropyl)dimethylamino)ethane-1-sulfonate, 3-((3-acrylamidopropyl)dimethylamino)propane-1-sulfonate, 4-((3-acrylamidopropyl)dimethylamino)butane-1-sulfonate, [3-(acryloyloxy)propyl](dimethylamino)acetate, dimethylaminopropylmethacrylamide derivatives, such as 2-((3-methacrylamidopropyl)dimethylamino)ethane-1-sulfonate, 3-((3-methacrylamidopropyl)dimethylamino)propane-1-sulfonate, 4-((3-methacrylamidopropyl)dimethylamino)butane-1-sulfonate and [3-(methacryloyloxy)propyl](dimethylamino)acetate and mixtures thereof.

[0190] Other hydrophilic zwitterionic monomers may be used, particularly those described by the applicant in document WO2021 / 123599.

[0191] The water-soluble polymer advantageously comprises 0 to 20 mol%, more preferably 0 to 10 mol%, of one or more zwitterionic monomers.

[0192] Allocation coefficient K ow Hydrophobic monomers with a concentration greater than 1 can also be used to prepare the polymers according to the invention. They are preferably selected from the following list: those having (i) C4-C 30 Alkyl, or (ii) arylalkyl (C4-C5) 30 Alkyl, C4-C 30 (iii) aryl, or (iv) propoxylated, or (v) ethoxylated, or (v) ethoxylated and propoxylated chains of (meth)acrylates; alkyl aryl sulfonates (C4-C 30 Alkyl, C4-C 30 Aryl); with (i)C4-C 30 Alkyl, or (ii) arylalkyl (C4-C5) 30 Alkyl, C4-C 30 (iii) aryl, or (iv) propoxylated, or (v) ethoxylated, or (v) monosubstituted or disubstituted (meth)acrylamides with ethoxylated and propoxylated chains; anionic or cationic monomeric derivatives of (meth)acrylamide or (meth)acrylic acid with hydrophobic chains; vinylpyridine and mixtures thereof. The hydrophobic monomer may contain a halogen atom, such as chlorine.

[0193] Among these hydrophobic monomers:

[0194] -Alkyl group is preferably C4-C 20 More preferably, C4-C8. C6-C 20 Alkyl groups are preferably straight-chain, while C4-C5 alkyl groups are preferably branched.

[0195] -Arylalkyl group is preferably C7-C 25 More preferably C7-C 15 ,

[0196] The ethoxylated chain advantageously comprises 1 to 200, preferably 6 to 100, more preferably 10 to 40 -CH2-CH2-O- groups.

[0197] -The propoxylated chain advantageously comprises 1 to 50, more preferably 1 to 20 -CH2-CH2-CH2-O- groups.

[0198] Preferred hydrophobic monomers belonging to these categories are, for example:

[0199] - (Meth)hexyl acrylate, (Meth)octyl acrylate, octyl(meth)acrylamide, (Meth)acrylate lauryl acrylate, lauryl(meth)acrylamide, (Meth)acrylate myristyl acrylate, myristyl(meth)acrylamide, (Meth)acrylate pentadecyl acrylate, pentadecyl(meth)acrylamide, (Meth)acrylate hexadecyl acrylate, hexadecyl(meth)acrylamide, (Meth)acrylate oleyl ester, oleyl(meth)acrylamide, (Meth)acrylate erucic acid ester, erucic acid (meth)acrylamide, N-tert-butyl(meth)acrylamide, 2-ethylhexyl acrylate, C4-C 22 Itaconic acid half ester, (meth)acrylic acid C4-C 22 Acidified or quaternized salts of dialkylaminoalkyl esters, C4-C 22 Acidified or quaternized salts of dialkylaminoalkyl (methyl)acrylamide, vinylpyridine, acrylamide undecanoic acid, and mixtures thereof.

[0200] - Cationic allyl derivatives of formula (I) or (II):

[0201]

[0202] in:

[0203] R: Independently an alkyl chain containing 1 to 4 carbons;

[0204] R1: An alkyl or aralkyl chain containing 8 to 30 carbon atoms;

[0205] X: Halides selected from the following groups: bromides, chlorides, iodides, fluorides, and any negatively charged counterions;

[0206] And preferably, the (meth)acryloyl type hydrophobic cationic derivative corresponding to formula (III):

[0207]

[0208] in:

[0209] -A represents O or N-R5 (preferably A represents N-R5).

[0210] -R2, R3, R4, R5, R6, R7: independently hydrogen or alkyl chains containing 1 to 4 carbons,

[0211] -Q: An alkyl chain containing 1 to 20 carbons.

[0212] -R8: An alkyl or aralkyl chain containing 8 to 30 carbons.

[0213] -X: Select from the following groups of halides: bromides, chlorides, iodides, fluorides, and any negatively charged counterions.

[0214] Water-soluble polymers advantageously contain less than 5 mol% of hydrophobic monomers.

[0215] When water-soluble polymers contain hydrophobic monomers, they are present in amounts that allow the polymer to remain soluble in water.

[0216] Monomers with fluorescent functional groups can also be used in this invention. Monomers with fluorescent functional groups can be detected by any suitable method, such as fluorescence assays using a fixed-wavelength fluorometer. Typically, monomers with fluorescent functional groups are detected at their excitation and emission maxima, which can be determined using a scanning fluorometer.

[0217] Monomers with fluorescent functional groups are selected from, for example, the following monomers: sodium styrene sulfonate or potassium styrene sulfonate, styrene sulfonic acid, vinylimidazolium and its derivatives, 9-vinylanthracene and its derivatives, N-9-xanthenylacrylamide and its derivatives, allyl dibenzosuberenol and its derivatives, chinconicin and its derivatives, quinine and its derivatives, cinchoninone and its derivatives, N,N-dimethyl-N-[3-[N'-(4-m'oxynaphthalimide)]]propyl-N-(2-hydroxy-3-allyloxy)propyl ammonium hydroxide and mixtures thereof.

[0218] When functionalized with allyl, vinyl, or acrylic double bonds, other fluorescent compounds can be used, such as pyranin and its derivatives, coumarin and its derivatives, quinoxaline and its derivatives, pinacyanol and its derivatives, xanthan alcohol and its derivatives, dabsyl and its derivatives, 3-hydroxy-2-methylene-3-(1-naphthyl)propionic acid and its derivatives, rhodamine and its derivatives, N-dibenzosuberylacrylamide and its derivatives, naphthalene derivatives, fluorescein and its derivatives, pyrene and its derivatives, quinolones and their derivatives, pyrazolines and their derivatives, and mixtures thereof.

[0219] In a preferred embodiment, the polymer does not contain monomers with fluorescent functional groups.

[0220] In a particular embodiment of the invention, the water-soluble polymer may comprise at least one cyclic monomer having a hydrolyzable functional group. Advantageously, one or more cyclic monomers having a hydrolyzable functional group are selected from cyclic ketene acetals, thionolactones, and mixtures thereof.

[0221] The cyclic enone acetal is advantageously selected from: 2-methylene-1,3-dioxane-heptane (MDO), 5,6-benzo-2-methylene-1,3-dioxane-heptane (BMDO), 2-methylene-4-phenyl-1,3-dioxane-pentane (MPDL), 2-methylene-1,3,6-trioxane-octane (MTC), and mixtures thereof. Preferably, it is 2-methylene-1,3-dioxane-heptane (MDO).

[0222] Thiolactones are advantageously selected from: dibenzo[c,e]oxazo(7H)-5-thione (DOT), ε-thiocaprolactone, 3,3-dimethyl-2,3-dihydro-5H-benzo[e][1,4]dioxazo-5-thione (DBT) and mixtures thereof. Preferably, it is 3,3-dimethyl-2,3-dihydro-5H-benzo[e][1,4]dioxazo-5-thione.

[0223] In a particular embodiment of the invention, the water-soluble polymer may contain at least one group having LCST.

[0224] As is common knowledge to those skilled in the art, a group having LCST corresponds to a group whose water solubility, for a given concentration, changes as a function of salinity above a specific temperature. It is a group with a heating transition temperature that defines its lack of affinity for the solvent medium. Lack of affinity for the solvent leads to opacity or loss of transparency, which can be due to precipitation, aggregation, gelation, or thickening of the medium. The lowest transition temperature is called the LCST (Lowest Critical Cosolution Temperature). For each concentration of a group having LCST, the heating transition temperature is observed. It is above the LCST, which is the lowest point on the curve. Below this temperature, the polymer dissolves in water; above this temperature, the polymer loses its solubility in water.

[0225] In one particular embodiment of the invention, the water-soluble polymer may contain at least one group having UCST.

[0226] Based on common knowledge in the art, a group having UCST corresponds to a group whose water solubility, for a given concentration, changes as a function of salinity below a specific temperature. It is a group with a cooling transition temperature, which defines its lack of affinity for the solvent medium. Lack of affinity for the solvent leads to opacity or loss of transparency, which can be due to precipitation, aggregation, gelation, or thickening of the medium. The highest transition temperature is called UCST (Upper Critical Cosolution Temperature). For each concentration of a group having UCST, the cooling transition temperature is observed. It is below UCST, which is the highest point on the curve. Above this temperature, the polymer is soluble in water; below this temperature, the polymer loses its solubility in water.

[0227] When preparing water-soluble polymers, the amount of one or more different monomers will be adjusted by those skilled in the art so as not to exceed 100 mol%.

[0228] Water-soluble polymers

[0229] The 2-acrylamido-2-methylpropanesulfonic acid used to obtain the water-soluble polymer is advantageously in the form of ATBS.Na, at least 50 mol%, preferably 70 to 100 mol%, crystalline form prior to polymerization. More preferably, the 100 mol% ATBS used is in the crystalline form of ATBS.Na.

[0230] In a specific embodiment of the invention, the water-soluble polymer comprises 1 to 100 mol% ATBS, preferably 5 to 100 mol% ATBS, and even more preferably 25 to 100 mol% ATBS; advantageously, at least 50 mol%, preferably 70 to 100 mol% of the ATBS used is in the crystalline form of ATBS.Na. More preferably, 100 mol% of the ATBS used is in the crystalline form of ATBS.Na.

[0231] In a preferred embodiment of the invention, the water-soluble polymer contains only anionic monomer units and nonionic monomer units. In other words, the water-soluble polymer is preferably obtained from at least one anionic hydrophilic monomer and at least one nonionic hydrophilic monomer.

[0232] In a specific embodiment of the invention, the water-soluble polymer is an acrylamide and an ATBS-based polymer, wherein at least 50 mol% of the ATBS used is in the crystalline form ATBS.Na prior to polymerization. Preferably, the water-soluble polymer is a polymer composed of acrylamide, acrylic acid, and ATBS, wherein at least 50 mol% of the ATBS is in the crystalline form ATBS.Na prior to polymerization.

[0233] In a preferred embodiment of the invention, the water-soluble polymer is a homopolymer of ATBS, and at least 50 mol% of the ATBS used is in the crystalline form of ATBS.Na.

[0234] Water-soluble polymers can be partially or completely hydrolyzed after hydrolysis.

[0235] According to the present invention, the water-soluble polymer can have a straight-chain, branched, cross-linked, star-shaped, or comb-like structure. Such a structure can be obtained based on common knowledge of those skilled in the art, for example by selecting the initiator, transfer agent, polymerization technique (e.g., controlled radical polymerization known as RAFT (Reversible Addition Fracture Chain Transfer), NMP (Nysoxide Radical Controlled Polymerization), or ATRP (Atom Transfer Radical Polymerization), and the incorporation or concentration of the structural monomer.

[0236] Water-soluble polymers can also be structured using branching agents. Structured polymers are nonlinear polymers with side chains that cause them to become highly entangled when dissolved in water, resulting in very high low-gradient viscosity.

[0237] The branching agent is advantageously selected from the following:

[0238] -Structural agents, which may be selected from the group comprising: polyolefin unsaturated monomers (having at least two unsaturated functional groups), such as vinyl functional groups, especially allyl or acrylic functional groups, and we may list, for example, methylenebisacrylamide (MBA), triallylamine, or tetraallyl ammonium chloride or 1,2-dihydroxyethylenebis(N-acrylamide),

[0239] - Monomers having at least two epoxy functional groups,

[0240] - Monomers having at least one unsaturated functional group and one epoxy functional group,

[0241] - Macromolecular initiators, such as polyperoxides, polyazoids, and transfer agents, such as polymercaptant polymers and polyols.

[0242] -Functionalized polysaccharides

[0243] - A water-soluble metal complex, which consists of the following:

[0244] *Metals with a valence greater than 3, such as, but not limited to, aluminum, boron, zirconium, or titanium, and

[0245] *Ligands containing hydroxyl functional groups.

[0246] 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 in the water-soluble polymer.

[0247] In one particular embodiment, the amount of branching agent is at least 0.1 ppm, preferably at least 1 ppm, relative to the total weight of the monomers of the water-soluble polymer.

[0248] When a 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 can adjust the amount of transfer agent required to obtain this result.

[0249] In a preferred embodiment of the invention, the water-soluble polymer does not contain a branching agent.

[0250] In one particular embodiment of the invention, the water-soluble polymer contains a transfer agent.

[0251] The transfer agent is advantageously selected from the following: methanol; isopropanol; sodium hypophosphite; calcium hypophosphite; magnesium hypophosphite; potassium hypophosphite; ammonium hypophosphite; formic acid; sodium formate; calcium formate; magnesium formate; potassium formate; ammonium formate; 2-mercaptoethanol; 3-mercaptopropanol; dithiopropylene glycol; thioglycerol; mercaptoacetic acid; mercaptopropionic acid; thiolactic acid; thiomalic acid; cysteine; aminoethanethiol; mercaptoacetate; allyl phosphites; allyl thiols, such as n-dodecyl thiols; sodium methylallyl sulfonate; calcium methylallyl sulfonate; magnesium methylallyl sulfonate; potassium methylallyl sulfonate; ammonium methylallyl sulfonate; alkyl phosphites, such as trialkyl phosphites (C 12 -C 15 ) esters, dioleyl hydrogen phosphite, dibutyl phosphite; dialkyl dithiophosphates, such as dioctyl phosphonate; tert-nonyl thiols; 2-ethylhexyl mercaptoacetate; n-octyl thiols; n-dodecyl thiols; tert-dodecyl thiols; isooctyl mercaptoacetate; 2-ethylhexyl mercaptoacetate; polythiols; and mixtures thereof. Sodium hypophosphite or sodium formate is preferred.

[0252] The amount of 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 in the water-soluble polymer. When a transfer agent is present, the transfer agent accounts for at least 0.1 ppm, preferably at least 1 ppm, relative to the total weight of the monomers in the water-soluble polymer.

[0253] In a particular embodiment of the invention, the water-soluble polymer does not contain a transfer agent.

[0254] Generally, water-soluble polymers do not require the development of any specific polymerization method. In fact, they can be obtained using any polymerization technique well known to those skilled in the art. These polymerization techniques include solution polymerization; gel polymerization; precipitation polymerization; emulsion polymerization (aqueous or reverse phase); suspension polymerization; reactive extrusion polymerization; water-in-water polymerization; or micellar polymerization.

[0255] Polymerization is typically free radical polymerization, preferably via reverse emulsion polymerization or gel polymerization. Free radical polymerization includes free radical polymerization using UV, azo, redox, or thermal initiators, as well as controlled radical polymerization (CRP) or matrix polymerization techniques.

[0256] Controlled radical polymerization techniques include, but are not limited to, various variants of iodine transfer polymerization (ITP), nitroxide radical-controlled polymerization (NMP), atom transfer radical polymerization (ATRP), reversible addition-fragmentation chain transfer (RAFT) polymerization (including MADIX (macromolecule design via xanthate exchange) technology), organometallic radical-controlled polymerization (OMRP), and organoheteroatom-controlled radical polymerization (OHRP).

[0257] As already noted, water-soluble polymers can be post-hydrolyzed. Post-hydrolysis is a hydrolysis reaction that occurs after the polymer has been polymerized from one or more monomers. This step involves reacting the hydrolyzable functional groups of the monomers (advantageously nonionic functional groups, more preferably amide or ester functional groups) with a hydrolyzing agent. This hydrolyzing agent can be an enzyme, an ion exchange resin, or... Acids (e.g., hydrohalic acids) or An alkali (e.g., an alkali metal hydroxide or an alkaline earth metal hydroxide). Preferably, the hydrolyzing agent is... Base. In the post-hydrolysis step of water-soluble polymers, 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 generates carboxylic acid groups.

[0258] When the preparation of water-soluble polymers includes a drying step (e.g., spray drying, drum drying, radiation drying such as microwave drying, or fluidized bed drying), the water-soluble polymers can be in liquid, gel, or solid form.

[0259] The weight-average molecular weight of the water-soluble polymer is advantageously at least 1 million g / mol, preferably 2 to 40 million g / mol, and more preferably 5 to 30 million g / mol. Molecular weight is defined as weight-average molecular weight.

[0260] Weight-average molecular weight is determined by the intrinsic viscosity of the polymer. Intrinsic viscosity can be measured using methods known to those skilled in the art and can be calculated graphically from the specific viscosity values ​​at different polymer concentrations. This graphical method involves plotting the specific viscosity values ​​(y-axis) against the concentration (x-axis) and extrapolating the curve to zero concentration. The intrinsic viscosity values ​​can be plotted on the y-axis or using the least squares method. The molecular weight can then be determined using the Mark-Houwink equation:

[0261] [η]=KM α

[0262] [η] represents the intrinsic viscosity of the polymer as determined by the solution viscosity method.

[0263] K represents an empirical constant.

[0264] M represents the molecular weight of the polymer.

[0265] α represents the Mark-Houwink coefficient.

[0266] K and α depend on the specific polymer-solvent system.

[0267] The filtration ratio (FR) of the water-soluble polymer is advantageously less than 1.5, preferably less than 1.3, and more preferably less than 1.1.

[0268] The term "filtration ratio" is used in this document to describe a test used to determine the performance of a polymer solution under conditions of similar mineral deposit permeability. This test involves measuring the time it takes for a given volume / concentration of solution to pass through a filter. FR typically compares the filterability of two consecutive equivalent volumes of polymer solution, indicating the tendency of the solution to clog the filter. A lower FR indicates better performance.

[0269] The test used to determine FR involves measuring the time it takes for a given volume of 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 specified pore size. FR is typically measured using filters with pore sizes of 1.2 μm, 3 μm, 5 μm, or 10 μm.

[0270] 100ml (t) was obtained by measurement 100ml ); 200ml (t) 200ml ) and 300ml (t 300ml The time required for the filtrate to be filtered is then defined as:

[0271] [Calculation 2]

[0272]

[0273] The time is accurate to 0.1 seconds.

[0274] Therefore, FR represents the ability of a polymer solution to clog a filter within two consecutive equivalent volumes.

[0275] The polymers used in this invention have improved resistance to chemical and thermal degradation compared to polymers of equivalent molecular weight obtained from ATBS (which is not a crystalline sodium salt).

[0276] Tests used to determine resistance to chemical degradation involve preparing a polymer solution at a given concentration in a given saline solution under aerobic conditions and then contacting it with a chemical contaminant (such as iron or hydrogen sulfide). The viscosity of the polymer solution is measured before and after 24 hours of exposure to the contaminant. Viscosity measurements are performed under the same temperature and shear gradient conditions.

[0277] The test used to determine resistance to mechanical degradation involves preparing a polymer solution of a given concentration in a brine of a given composition under anaerobic conditions (e.g., inertized with nitrogen using an inert glove box) and aging it for a predetermined time in a stainless steel tank set to a given temperature. The stainless steel tank is then cooled to room temperature, and the viscosity of the polymer solution it contains is measured and compared to its initial value. All operations on the stainless steel tank are performed within a glove box to avoid exposure to oxygen. The stainless steel tank is sealed to prevent oxygen from entering the solution during thermal aging. Viscosity measurements before and after aging are performed in the glove box under the same temperature and rate gradient conditions.

[0278] Resistance to chemical and thermal degradation was quantified by viscosity loss values ​​expressed as a percentage and determined at the end of the test by the following:

[0279] [Calculation 3]

[0280]

[0281] Methods to enhance hydrocarbon (oil and / or natural gas) recovery

[0282] This invention relates to a method for enhancing hydrocarbon (oil and / or natural gas) recovery, comprising the following steps:

[0283] a) Prepare an injection fluid containing at least one water-soluble polymer of ATBS using water or brine;

[0284] Prior to polymerization, ATBS exists in crystalline form as sodium ATBS (ATBS.Na), which has an X-ray powder diffraction pattern with peaks at the following positions: 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°; 47.6° (2θ angle);

[0285] b) Inject the injection fluid into the underground formation;

[0286] c) Using injected fluid to penetrate underground strata;

[0287] d) Harvest mixtures of hydrous hydrocarbons.

[0288] When the water-soluble polymer used to prepare the injection fluid is in powder form, the average size of the water-soluble polymer particles is advantageously less than 1.5 mm, preferably less than 850 μm. The average size of the water-soluble polymer particles is advantageously greater than 5 μm.

[0289] The average size of water-soluble polymer particles is the average size of the largest particles, for example, the diameter in the case of spherical particles. Advantageously, a laser measuring device is used to measure the average size of water-soluble polymer particles using conventional techniques that are partly known to those skilled in the art. For example, the Malvern Mastersizer (MS2000) can be used for this purpose. This type of device can be used to measure the particle size distribution of particles in liquid media or solid forms by laser diffraction.

[0290] When water-soluble polymers are in particulate form, they can be dissolved in an aqueous medium in a dispersion device. The polymer slicer unit (PSU) described in US8,186,871 is an example of a dispersion device that can be used to prepare concentrated aqueous polymer solutions.

[0291] The water or brine used to prepare the injection fluid can be produced water. "Produced water" refers to any saline or non-saline, brine, seawater, or aquifer water from a hydrocarbon reservoir. As described in patent application WO2018 / 020175, the produced water can be treated prior to the preparation of the injection fluid.

[0292] Water-soluble polymers can be combined with stabilizing compounds. Stabilizing compounds (stabilizers) can be compounds suitable for protecting polymers (e.g., preventing thermal, chemical, and / or mechanical degradation). Examples of suitable stabilizers are provided in patent application WO 2010 / 133258.

[0293] Depending on the technology used, the injected fluid containing water-soluble polymers is injected alone or in combination with one or more compounds that can be used to enhance hydrocarbon (oil and / or natural gas) recovery. These compounds include weak, strong, or super-strong inorganic or organic bases that saponify crude oil and generate in situ dissolved hydrocarbons (especially petroleum) by surfactants. Examples include sodium or potassium carbonate, caustic soda, borate and metaborate compounds, amines, and basic polymers. Another class of compounds typically injected with polymers are surfactants, which are usually anionic, amphoteric, cationic, and sometimes nonionic. These compounds are rarely injected in pure form but are usually injected with co-surfactants and co-solvents to improve their compatibility and effectiveness in the reservoir (subsurface formation).

[0294] The injected fluid advantageously contains 10 to 15,000 ppm, preferably 50 to 10,000 ppm, more preferably 100 to 5,000 ppm by weight of a water-soluble polymer.

[0295] Surprisingly, the applicant has discovered that water-soluble polymers obtained from crystalline sodium ATBS exhibit better filterability and resistance to chemical and thermal degradation than polymers of the same molecular weight obtained from non-crystalline sodium ATBS. It is known that filterability deteriorates with increasing polymer molecular weight. One advantage of this invention is the ability to obtain very high molecular weight water-soluble polymers that simultaneously exhibit good filterability. Furthermore, the reduced concentration of water-soluble polymer required to achieve the target viscosity of the injected fluid improves the economics of extracting hydrocarbons (oil and / or natural gas) contained in formations.

[0296] The purpose of the water-soluble polymer according to the present invention is to thicken water injected into reservoirs (subsurface formations) containing hydrocarbons (oil and / or natural gas) to ensure flow control without the need for crosslinking (i.e., chemical interchain bridging).

[0297] In one particular implementation, a method for enhancing hydrocarbon (oil and / or natural gas) recovery includes the following steps:

[0298] a) Preparation of an injection fluid containing a water-soluble polymer with a molecular weight greater than 5 million g / mol:

[0299] - The injected fluid has a salt concentration greater than 100 g / L, which includes up to 50 g / L of one or more divalent salts;

[0300] - A polymer containing at least 80 mol% ATBS, wherein advantageously, at least 50 mol%, preferably at least 70 mol%, more preferably 100 mol% of ATBS is in crystalline form prior to polymerization.

[0301] - The concentration of water-soluble polymers in the injected fluid is less than 3000 ppm by weight;

[0302] -The viscosity of the injected fluid prior to shearing step b) is V1;

[0303] b) Shear injection of fluid to obtain a viscosity reduction of more than 25% relative to V1, wherein:

[0304] [Calculation 4]

[0305] in,

[0306] V1 is the viscosity of the injected fluid at the formation temperature before the shearing step;

[0307] V2 is the viscosity of the injected fluid at formation temperature after the shearing step;

[0308] V 水 It is the viscosity of water at formation temperature used to prepare the injected fluid;

[0309] c) Injecting the fluid into the subsurface formation, which is a carbonate formation with a permeability of less than 300 millidarcy and a temperature greater than 100°C;

[0310] d) Using injected fluid to penetrate underground strata;

[0311] e) Recover mixtures of aqueous hydrocarbons (petroleum and / or natural gas).

[0312] The shearing step can be performed, for example, using a valve, port, or pump.

[0313] Preferably, the concentration of one or more divalent salts in the injected fluid is 3 to 50 g / L.

[0314] Carbonate formations are sedimentary rock formations in which carbonates constitute at least 50% of the rock.

[0315] In order to illustrate the invention in a non-limiting manner, the invention and its advantages will be better understood with reference to the accompanying drawings and embodiments provided below. Attached Figure Description

[0316] Figure 1 The proton NMR spectrum of the ATBS needle crystal obtained according to Example 1 is shown.

[0317] Figure 2 The proton NMR spectrum of ATBS.Na crystals obtained according to Example 2a is shown.

[0318] Figure 3 An X-ray diffraction pattern of the ATBS crystal obtained according to Example 1 is shown.

[0319] Figure 4 The X-ray diffraction pattern of the ATBS.Na crystal obtained according to Example 2a is shown.

[0320] Figure 5 The Fourier transform infrared spectrum of the ATBS crystal obtained in Example 1 is shown.

[0321] Figure 6 The Fourier transform infrared spectrum of the ATBS.Na crystal obtained in Example 2a is shown.

[0322] Figure 7 The temperature spectrum of the ATBS crystal obtained according to Example 1 is shown.

[0323] Figure 8 The temperature spectrum of ATBS.Na crystals obtained according to Example 2a is shown.

[0324] Figure 9 The ATBS form of polymer P3-A in contact with different amounts of iron(II) contaminants is shown. Na 2a (the present invention) and P'3-A H The effect of viscosity loss on (acidic form of ATBS) solution.

[0325] Figure 10 This shows that when polymer P6-A Na 2a (the present invention) and P'6-A H The effect of ATBS form on viscosity loss when aged at 90°C (acidic form of ATBS).

[0326] Figure 11 The ATBS form of polymer P6-A in contact with different amounts of iron(II) contaminants is shown. Na 2a (the present invention) and P'6-A H The effect of viscosity loss on (acidic form of ATBS) solution.

[0327] Figure 12 An optical microscope view of an ATBS crystal obtained according to Example 1 is shown.

[0328] Figure 13 An optical microscope view of an ATBS.Na crystal obtained according to Example 2a is shown.

[0329] Figure 14 An optical microscope view of the ATBS.Na crystal obtained according to Example 2b is shown.

[0330] Figure 15 An optical microscope view of an ATBS.Na crystal obtained according to Example 2c is shown.

[0331] Figure 16 A photograph of the ATBS.Na product obtained according to Comparative Example 2a in solution is shown.

[0332] Figure 17 An optical microscope view of an ATBS.Na crystal obtained according to Comparative Example 2c is shown.

[0333] Figure 18 An optical microscope view of an ATBS.Na crystal obtained according to Comparative Example 2d is shown.

[0334] Figure 19 An optical microscope view of an ATBS.Na crystal obtained according to Comparative Example 2e is shown. Detailed Implementation

[0335] Example

[0336] Example 1: 2-Acrylamido-2-methylpropanesulfonic acid (ATBS) (A) H Synthesis of )

[0337] 1522g of acrylonitrile containing 0.4% water by weight was added to a stirred double-jacketed 2000ml reactor. The mixture was stirred for 1 hour and cooled through the double jacket of the reactor, which kept the temperature of the sulfonated mixture at -20°C. Then, 180g of fuming sulfuric acid (18% oleum) with a titration of 104% H2SO4 was added.

[0338] 97 g of isobutylene was added to the preceding sulfonation mixture at a rate of 1.6 g / min.

[0339] When isobutylene was added, the temperature of the mixture was controlled at 45°C. Particles of 2-acrylamido-2-methylpropanesulfonic acid precipitated from the mixture, with a solid content of approximately 20% by weight. The reaction mixture was filtered through a Büchner funnel and dried under vacuum at 50°C. The resulting solid was 2-acrylamido-2-methylpropanesulfonic acid (ATBS A) in the form of a very fine white powder. H ).

[0340] Optical microscopy observation ( Figure 12 ) shows ATBS A H The crystals have a needle-like morphology.

[0341] Example 2a: Sodium 2-acrylamido-2-methylpropanesulfonate in crystalline form (ATBS.Na A) Na 2a) Formation of (the present invention)

[0342] 439 g of a 22% (by weight in water) sodium hydroxide solution was added to a stirred, double-jacketed 1000 ml reactor. 452 g of ATBS A from Example 1 was added. H Add to the mixture above.

[0343] The mixture was stirred at 10°C for 30 minutes to form an aqueous solution SA2.

[0344] The aqueous solution SA2 was heated to 40°C under a vacuum of 50 mbar for 20 min, then held at that temperature under a vacuum of 50 mbar for 30 min and cooled to 10°C. The cooling time from 40°C to 10°C was 6 h. A suspension S1 of ATBS.Na crystals was obtained. Suspension S1 was filtered on a Robataer vertical centrifuge. A solid of composition C1 was obtained, containing 80 wt% ATBS.Na. Na 2a crystal.

[0345] Optical microscopy observation ( Figure 13 A is shown Na 2a crystals have columnar and plate-like morphologies.

[0346] Example 2b: Sodium ATBS in crystalline form (ATBS.Na A) Na 2b) formation

[0347] ATBS-Na A was prepared according to the procedure described in Example 2a. Na 2b crystals, the difference being that SA2 is distilled at 700 mbar.

[0348] Optical microscopy observation ( Figure 14 The diagram shows the A obtained under these conditions. Na 2b crystals are similar to the ATBS.NaA crystals prepared in Example 2a. Na 2a crystals are identical.

[0349] Example 2c: Sodium ATBS in crystalline form (ATBS.Na A) Na 2c) formation

[0350] ATBS-Na A was prepared according to the procedure described in Example 2a. Na The 2c crystal differs in that the cooling time is reduced to 3 hours and 45 minutes.

[0351] Optical microscopy observation ( Figure 15 The image shows crystals obtained under these conditions and ATBS.Na A Na 2a crystals are identical.

[0352] Comparative Example 2a: Preparation of ATBS.Na crystals (CE-A) under atmospheric pressure (1 bar) Na 2a)(Not obtained)

[0353] The reaction was carried out according to the procedure described in Example 2a, except that SA2 was distilled at atmospheric pressure.

[0354] At the end of the cooling step, the aqueous solution SA2 is not allowed to form a suspension S1, and filtration or centrifugation cannot be performed to separate the ATBS sodium salt crystals.

[0355] Comparative Example 2b: Sodium ATBS crystals (CE-A) Na Preparation of 2b) (not obtained)

[0356] The reaction was carried out under the conditions described in Example 27 of patent application US6331647.

[0357] Add 124g of sodium hydroxide and 0.13g of hydroquinone monomethyl ether to a stirred, double-jacketed 5000ml reactor containing 400g of water. Stir the medium until all the sodium hydroxide is dissolved.

[0358] 632g ATBS A H Add to the previous mixture. Stir the mixture at 10°C for 30 min to form an aqueous solution of sodium 2-acrylamido-2-methylpropanesulfonate.

[0359] The resulting aqueous solution was filtered in a 3000 ml reactor equipped with a distillation apparatus and an air purification tube. The contents were heated and stirred while air was blown onto the surface at a rate of 0.5 cubic feet per hour. The contents were heated to 50°C under a vacuum of 933 mabr (~700 mmHg). As water was removed, a pale yellow, honey-like product was formed. The product was then transferred to a Robatael vertical centrifuge, but no solids were recovered.

[0360] Since no solid was obtained, optical microscopy observation was not possible. Figure 16 ).

[0361] Comparative Example 2c: Sodium ATBS crystals (CE-A) Na Preparation of 2c) (not obtained)

[0362] The reaction was carried out under the conditions described in Example 3 of patent application WO2013079507.

[0363] 100 g of ATBS.Na solution (16.77 wt%) was obtained according to Example 1 of WO2013079507.

[0364] 50 g of solvent (a mixture of acrylonitrile and methanol) was removed from an ATBS.Na solution at room temperature under reduced pressure (less than 700 mbar) while air was introduced into the ATBS.Na solution. This formed ATBS.Na CE-A. Na The solid at 2c was filtered and washed with acrylonitrile / methanol, and then dried overnight at 50°C.

[0365] Optical microscopy observation ( Figure 17 The diagram shows ATBS.Na CE-A. Na The dry solid of 2c does not correspond to the ATBS.Na crystal according to the present invention.

[0366] Comparative Example 2d: ATBS.Na CE-A Na Preparation of 2D (not based on this invention)

[0367] The reaction was carried out according to the procedure described in Example 2a, except that SA2 was distilled at 720 mbar.

[0368] A solid of composition C1 is obtained, which contains 80% by weight of ATBS, Na, CE-A Na 2D crystal.

[0369] Optical microscopy observation ( Figure 18 The diagram shows ATBS.Na CE-A. Na The dry solid of 2c does not correspond to the ATBS.Na crystal according to the present invention.

[0370] Comparative Example 2e: ATBS.Na CE-A Na Preparation of 2e (not according to the present invention)

[0371] The reaction was carried out according to the procedure described in Example 2a, except that the cooling time was 3 hours and 20 minutes.

[0372] A solid of composition C1 is obtained, which contains 80% by weight of ATBS, Na, CE-A Na 2e crystal.

[0373] Optical microscopy observation ( Figure 19 ) shows ATBS.Na CE-A Na The dry solid of 2e does not correspond to the ATBS.Na crystal according to the present invention.

[0374] Example 3: ATBS A of Examples 1 and 2a H and ATBS.Na A NaNMR analysis of product 2a

[0375] ATBS A H and ATBS.Na A Na 2a was analyzed by proton nuclear magnetic resonance (NMR).

[0376] The sample was dissolved in D2O. The NMR instrument was a Bruker model with a frequency of 400MHz and equipped with a 5mm BBOBB- 1 H.

[0377] Two proton spectra ( Figure 1 and 2 Similarly, the peak assignments are consistent with the molecular structure of ATBS or sodium salt.

[0378] Example 4: ATBS A of Examples 1 and 2a H and ATBS.Na A Na X-ray diffraction analysis of 2a

[0379] Pre-ground ATBS A H and ATBS.Na A Na The 2a crystals were formed into powder and analyzed by X-ray diffraction in the 10 to 90° angle range. The instrument used was a Rigaku MiniFlex II diffractometer equipped with a copper source.

[0380] ATBS.Na A Na 2a crystal ( Figure 4 The X-ray diffraction pattern shows the following characteristic peaks: 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°; 47.6° 2θ angle (+ / -0.1°).

[0381] ATBS A H X-ray diffraction pattern ( Figure 3 There are no identical peaks.

[0382] Example 5: ATBS A H and ATBS.Na A Na Fourier transform infrared measurement of 2a

[0383] The device used for Fourier transform infrared measurements was a Perkin ElmerSpectrum 100 equipped with a single-reflection ATR polarization accessory, with an accuracy of 8 cm. -1 .

[0384] ATBS A H and ATBS.Na A Na 2a crystals were sieved to 100 μm. The particles remaining on the sieve were dried and placed in an oven at 60 °C for at least 4 h.

[0385] Hundreds of milligrams of solid were placed on the diamond in the ATR attachment, and pressure was applied manually using the attachment.

[0386] The following spectral bands ( Figure 6 ) is crystalline form of ATBS.Na A Na Characteristics of 2a: 3576cm -1 3485cm -1 3310cm -1 3079cm -1 2975cm -1 1658cm -1 1629cm -1 1543cm -1 1403cm -1 1321cm -1 1301cm -1 1205cm -1 1187cm -1 1163cm -1 1046cm -1 980cm -1 629cm -1 .

[0387] ATBS A H infrared spectrum ( Figure 5 There are no identical peaks.

[0388] Example 6: ATBS A of Examples 1 and 2a H and ATBS.Na A Na Differential scanning calorimetry (DSC) of product 2a

[0389] The device used is a Mettler DSC 3.

[0390] ATBS A H and ATBS.Na A Na The 2a crystals were analyzed under a nitrogen flow at a heating rate of 10 °C / min. The initial temperature was 30 °C, and the product was heated to 350 °C.

[0391] ATBS A H Temperature spectrum ( Figure 7 The figure shows the thermal effect at a temperature of 195.15°C, which is generally considered to be the melting / degradation point of ATBS. Subsequently, two exothermic degradation phenomena occurred at 212.8°C and 288.4°C.

[0392] ATBS.Na A Na Temperature spectrum of crystal 2a ( Figure 8 The figure shows four thermal phenomena at 49.8℃, 144.8℃, 169.8℃, and 254.3℃.

[0393] Example 7: Polymer P1-A of Acrylamide (AM) / ATBS (75 / 25 mol%) Na Preparation of 2a

[0394] Mix 1035g deionized water, 520.5g AM (50% by weight aqueous solution), 16.2g urea, and 285g ATBS. Na A Na Add 2a to a 2000mL beaker.

[0395] The resulting solution is cooled to 5 to 10°C and transferred to an adiabatic polymerization reactor in which nitrogen gas is bubbled through for 30 minutes to eliminate any trace amounts of dissolved oxygen.

[0396] Then add the following substances to the reactor:

[0397] -0.45g 2,2'-azobisisobutyronitrile,

[0398] -1.5 ml of 2.5 g / L 2,2'-azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride solution,

[0399] -10ml of 1g / L sodium hypophosphite solution,

[0400] -1.5 ml of 1 g / L tert-butyl hydrogen peroxide solution,

[0401] -1.5 ml of 1 g / L ammonium sulfate and ferric(II) hexahydrate (molar salt) solution.

[0402] 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 temperature peak is reached. The resulting rubbery gel is chopped and dried to obtain a coarse powder, which is then ground and sieved to obtain the polymer in powder form.

[0403] The gel was then dried and ground to obtain polymer P1-A in powder form. Na 2a.

[0404] Polymer P1-A was obtained by varying the amount of sodium hypophosphite. Na Method 2a was used to obtain polymer P2-A Na 2a, P3-A Na 2a and P4-A Na 2a.

[0405] P2-A Na 2a: 1.5 ml of 3 g / L sodium hypophosphite solution

[0406] P3-A Na 2a: 1 ml of 3 g / L sodium hypophosphite solution

[0407] P4-A Na 2a: 1.5 ml of 1 g / L sodium hypophosphite solution

[0408] Example 8: Preparation of comparative polymers P'1 to P'3 of AM / ATBS polymer (75 / 25 mol%)

[0409] Polymer P'1-A H P'2-A H and P'3-A H It uses 257gATBS A according to the scheme described for P1 to P3 in Example 7. H It was obtained by mixing 99g of a 50% by weight sodium hydroxide aqueous solution.

[0410] Polymer P'1-CEA Na 2c, P'2-CEA Na 2c, P'3-CEA Na 2c is the use of ATBS CE-A according to the scheme described in Example 7. Na Obtained in 2c.

[0411] Polymer P'1-CEA Na 2d, P'2-CEA Na 2d, P'3-CEA Na 2d is the use of ATBS CE-A according to the scheme described in Example 7. Na Obtained in 2D.

[0412] Polymer P'1-CEA Na 2e, P'2-CEA Na 2e, P'3-CEA Na 2e is the use of ATBS CE-A according to the scheme described in Example 7. Na Obtained in 2e.

[0413] Example 9: Measurement of the filtration ratio of polymer solution

[0414] The polymers prepared in Examples 7 and 8 were subjected to filtration tests.

[0415] The results are presented in Table 1.

[0416] A polymer solution (ppm by weight) was obtained in a brine containing water, 30,000 ppm NaCl, and 3,000 ppm CaCl₂,₂H₂O at an activity concentration of 1,000 ppm. The filtration ratio (FR) was measured on a filter with a pore size of 1.2 μm, representing a low-permeability deposit.

[0417]

[0418] Table 1: Polymers with tested filtration ratios

[0419] Table 1 shows the polymers (P1 to P3-A) obtained from crystalline ATBS.Na at the same molecular weight. Na 2a) is always more efficient than polymers obtained from the amorphous form of ATBS.Na (P'1 to P'3-A). H Polymers obtained from ATBS in a crystalline form not according to the invention have lower FR. This difference becomes increasingly pronounced as the polymer molecular weight increases. A polymer with a molecular weight of 13 million Da (P4-A) obtained from crystalline ATBS.Na... Na 2a) Even lower molecular weight (11.5 million Da, P'3-A) than that obtained from the amorphous form of ATBS.Na. H Polymers of ATBS-Na or polymers obtained from different crystalline forms of ATBS-Na (P'3-CEA) Na 2c-e) has a lower FR.

[0420] Example 10: Measurement of chemical degradation resistance of polymer solutions of equal molecular weight

[0421] Chemical degradation resistance tests (ppm by weight) of polymer P3 and control polymer P'3 were conducted under aerobic conditions in the presence of different concentrations of iron(II) (2, 5, 10, and 20 ppm) in a saline solution composed of water, 37,000 ppm NaCl, 5,000 ppm Na₂SO₄, and 200 ppm NaHCO₃. Results were obtained after 24 hours of contact between the polymer solution and the contaminant. Figure 9 As shown.

[0422] The results are presented in Table 2.

[0423] <![CDATA[P3-A Na 2a]]> 2 3.5 <![CDATA[P’3-A H ]]> 2 6 <![CDATA[P’3-CEA Na 2c]]> 2 6.5 <![CDATA[P’3-CEA Na 2d]]> 2 6 <![CDATA[P’3-CEA Na 2e]]> 2 7 <![CDATA[P3-A Na 2a]]> 5 4.5 <![CDATA[P’3-A H ]]> 5 9 <![CDATA[P’3-CEA Na 2c]]> 5 8.8 <![CDATA[P’3-CEA Na 2d]]> 5 9.3 <![CDATA[P’3-CEA Na 2e]]> 5 9.9 <![CDATA[P3-A Na 2a]]> 10 11 <![CDATA[P’3-A H ]]> 10 14 <![CDATA[P’3-CEA Na 2c]]> 10 14 <![CDATA[P’3-CEA Na 2d]]> 10 14.8 <![CDATA[P’3-CEA Na 2e]]> 10 14.6 <![CDATA[P3-A Na 2a]]> 20 24 <![CDATA[P’3-A H ]]> 20 34 <![CDATA[P’3-CEA Na 2c]]> 20 35 <![CDATA[P’3-CEA Na 2d]]> 20 35.5 <![CDATA[P’3-CEA Na 2e]]> 20 34.8

[0424] Table 2: Polymer P3-ANa 2a and contrast polymer P'3-A H and P'3-CEA Na Measurement of chemical degradation resistance of 2c-2e.

[0425] It can be seen that for each iron(II) concentration, polymer P3-A Na 2a compared to the equivalent comparative polymer P'3-A H P'3-CEA Na 2c, P'3-CEA Na 2d, P'3-CEA Na 2e experiences less viscosity loss.

[0426] Example 11: Measurement of the thermal degradation resistance of polymer solutions of equal molecular weight

[0427] Under anaerobic conditions, in a brine solution composed of 30,000 ppm NaCl and 3,000 ppm CaCl2,2H2O, at an active concentration of 2,000 ppm, the activity of P3-A was investigated. Na The heat degradation resistance (ppm by weight) of polymers 2a and P'3 was tested. The polymer solutions were aged at 90°C for 6 months. The results are shown in the form of viscosity loss. Figure 10 middle.

[0428] The results are presented in Table 3.

[0429] <![CDATA[P3-A Na 2a]]> 8 <![CDATA[P’3-A H ]]> 18.6 <![CDATA[P’3-CEA Na 2c]]> 18 <![CDATA[P’3-CEA Na 2d]]> 18.4 <![CDATA[P’3-CEA Na 2e]]> 19

[0430] Table 3: Polymer P3-A Na 2a and P'3-A H P'3-CEA Na Measurement of the thermal degradation resistance of 2c-e

[0431] We can see that P3-A Na 2a compared to the equivalent comparative polymer P'3-A H and P'3-CEA Na 2c-e results in less viscosity loss.

[0432] Example 12: Preparation of homopolymers P5-P7 from ATBS.Na in its crystalline form according to the present invention.

[0433] Polymer P5-A Na 2a is the preparation of polymers P1 to P3-A according to the method described in Example 7. Na The preparation was carried out according to scheme 2a, wherein the amounts of monomer and excipient were adjusted to achieve the desired molar composition of 100 mol% ATBS (using 30 ml of 1 g / L sodium hypophosphite solution).

[0434] Polymer P6-A Na 2a and P7-A Na 2a is based on polymer P5-A Na 2a was prepared using the same scheme but with different amounts of sodium hypophosphite (using 1.5 ml of 1 g / L sodium hypophosphite solution).

[0435] Example 13: Preparation of comparative homopolymers P'5 to P'7 of ATBS (not based on the present invention)

[0436] Comparative polymer P'5-A H P'6-A H and P'7-A H 452g of ATBSA was used according to the scheme described in Example 12. H It was prepared with 175g of a 50% by weight sodium hydroxide aqueous solution.

[0437] Using ATBS.Na CE-A Na 2c Preparation of polymer P'5-CEA Na 2c, P'6-CEA Na 2c.

[0438] Using ATBS.Na CE-A Na Polymer P'5-CEA prepared in 2 days Na 2d, P'6-CEA Na 2d.

[0439] Using ATBS.Na CE-A Na 2e Preparation of polymer P'5-CEA Na 2e, P'6-CEA Na 2e.

[0440] Example 14: Measurement of the filtration ratio of polymer solutions containing polymers P5 to P7 and control polymers P'5 to P'7

[0441] The polymers prepared in Examples 12 and 13 were subjected to filtration tests. When using the amorphous form of ATBS.Na according to the invention, polymer P7-A with a molecular weight in the range of 15 million Da could not be obtained. Na 2a. The results are shown in Table 4.

[0442] A polymer solution (ppm by weight) was obtained in a brine containing water, 30,000 ppm NaCl, and 3,000 ppm CaCl₂,₂H₂O at an activity concentration of 1,000 ppm. The filtration ratio (FR) was measured on a filter with a pore size of 1.2 μm, representing a low-permeability deposit.

[0443] Table 4: Polymers with tested filtration ratios

[0444] Table 4 shows that, at the same molecular weight, polymers obtained from the crystalline form of ATBS.Na according to the invention always have a lower FR than polymers obtained from the amorphous form of ATBS.Na not according to the invention. This difference becomes increasingly pronounced as the polymer molecular weight increases. The polymer with a molecular weight of 15 million Da obtained from the crystalline form of ATBS.Na (P7) is even lower than the polymer with a molecular weight of 5.3 million Da obtained from the amorphous form of ATBS.Na (P'6-A). H Polymers of ATBS-Na or polymers obtained from different crystalline forms (P'6-CEA) Na 2c-e) has a lower FR.

[0445] Example 15: Measurement of chemical degradation resistance of polymer solutions of equal molecular weight

[0446] Under aerobic conditions, in the presence of different concentrations of iron(II) (2, 5, 10, and 20 ppm) in a brine composed of water, 37,000 ppm NaCl, 5,000 ppm Na₂SO₄, and 200 ppm NaHCO₃, polymers P6-ANa₂a and the comparative polymer P'₆-A were tested. H and P'6-CEA Na Chemical degradation resistance test (ppm by weight) of 2c-e. Results obtained after 24 hours of contact between polymer solution and contaminant. Figure 11 As shown.

[0447] The results are presented in Table 5.

[0448]

[0449] Table 5: Polymer P6-A according to the present invention Na Measurement of the chemical degradation resistance of polymer 2a and the comparative polymer P'6.

[0450] It can be seen that, for each iron(II) concentration, the polymer according to the invention experiences less viscosity loss than the equivalent comparative polymer P'6.

[0451] Example 16: The polymer P8-A of AM / ATBS (75 / 25 mol%) according to the present invention Na Preparation of 2a.

[0452] Polymer P8-A Na2a was prepared according to the scheme for preparing polymer P1 described in Example 7, wherein the amounts of monomer and excipient were adjusted to achieve the desired AM / ATBS (75 / 25) molar composition.

[0453] Post-hydrolysis of acrylamide: 500.0 g of pre-cut gel was then mixed with 16.0 g of 50% sodium hydroxide aqueous solution, and the mixture was heated and held at 90 °C for 90 min.

[0454] The gel was then dried and ground to obtain polymer P8-A in powder form. Na 2a.

[0455] Example 17: Preparation of the comparative polymer P'8 of AM / ATBS (75 / 25 mol%).

[0456] Polymer P'8-A H 257g of ATBS A was used according to the scheme described in Example 16. H It was prepared with 99.5g of a 50% by weight sodium hydroxide aqueous solution.

[0457] Polymer P'8-CEA Na 2c is the use of CE-A according to the scheme described in Example 16. Na Prepared from 2c crystals.

[0458] Polymer P'8-CEA Na 2d is the use of CE-A according to the scheme described in Example 16. Na Prepared from 2D crystals.

[0459] Polymer P'8-CEA Na 2e is the use of CE-A according to the scheme described in Example 16. Na Prepared from 2e crystals.

[0460] Example 18: Measurement of the filtration ratio of polymer solution

[0461] The polymers obtained in Examples 16 and 17 were subjected to filtration tests. The results are presented in Table 6.

[0462] A polymer solution (ppm by weight) was obtained in a brine containing water, 30,000 ppm NaCl, and 3,000 ppm CaCl₂,₂H₂O at an active concentration of 1,000 ppm. The filtration ratio (FR) was measured on a filter with a pore size of 3 μm, representing a low-permeability deposit.

[0463] Table 6: Filtration efficiency ratio of polymer P8 according to the present invention and comparative polymer P'8

[0464] Table 6 shows that, despite the high molecular weight, the polymer (P8-A) obtained from the crystalline form of ATBS.Na... Na 2a) Possesses polymers (P8-A) obtained from amorphous ATBS. H ) or polymers obtained from ATBS in different crystalline forms (P'8-CEA) Na 2c-e) equivalent to FR.

[0465] Example 19: Preparation of copolymers P9 and P'9 of AM / acrylic acid (AA) / ATBS (75 / 10 / 15 mol%)

[0466] The experimental procedures of Examples 7 and 8 were repeated, except that the amounts of different monomers were adjusted to achieve the desired molar composition of AM / AA acid / ATBS, and polymer P9-A was obtained. Na 2a, P'9-A H and P'9-CEA Na 2c to 2e.

[0467] Example 20: Preparation of polymer P10 / P'10 of AM / quaternized dimethylaminoethyl acrylate.CH3Cl(DMEA.MeCl) / ATBS (60 / 5 / 35 mol%)

[0468] The experimental procedures of Examples 7 and 8 were repeated, except that the amounts of different monomers were adjusted to achieve the desired molar composition of AM / DMEA.MeCl / ATBS, and polymer P10-A was obtained. Na 2a, P'10-A H and P'10-CEA Na 2c to 2e.

[0469] Example 21: Preparation of polymer P11 / P'11 of AM / diallyldimethylammonium chloride (DADMAC) / ATBS (75 / 5 / 20 mol%)

[0470] The experimental procedures of Examples 7 and 8 were repeated, except that the amounts of different monomers were adjusted to achieve the desired molar composition of AM / DADMAC / ATBS, and polymer P11-A was obtained. Na 2a, P'11-A H and P'11-CEA Na 2c to 2e

[0471] Example 22: Measurement of chemical degradation resistance of polymer solutions of equal molecular weight

[0472] The chemical degradation resistance (ppm by weight) of the polymers of Examples 19-21 was tested under aerobic conditions in the presence of different concentrations of iron(II) (2, 5, 10, and 20 ppm) in a brine consisting of water, 37,000 ppm NaCl, 5,000 ppm Na₂SO₄, and 200 ppm NaHCO₃. All polymers had the same chemical composition. The results are presented in Table 7.

[0473]

[0474]

[0475] Table 7: Measurement of the chemical degradation resistance of polymers in Examples 16-18

[0476] It can be seen that, for each iron(II) concentration, the polymers P9 to P11 according to the invention experience less viscosity loss than their equivalent comparative polymers not prepared with ATBS.Na in the crystalline form according to the invention.

[0477] Example 23: Measurement of the filtration ratio of the polymer solutions in Examples 19-21

[0478] The polymers prepared in Examples 19-21 were subjected to filtration tests. The results are presented in Table 8.

[0479] A polymer solution (ppm by weight) was obtained in a brine containing water, 30,000 ppm NaCl, and 3,000 ppm CaCl₂,₂H₂O at an activity concentration of 1,000 ppm. The filtration ratio (FR) was measured on a filter with a pore size of 3 μm, representing a low-permeability deposit.

[0480] Table 8: Filtration ratios of polymers P9 to P11 according to the present invention and comparative polymers P'9 to P'11

[0481] Table 8 shows that, despite their higher molecular weights, polymers obtained from crystalline ATBS.Na (P9 to P11) have FRs comparable to those obtained from amorphous ATBS or from different crystalline forms of ATBS.Na.

Claims

1. A method for enhancing hydrocarbon recovery, 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; The ATBS prior to polymerization is in the crystalline form of sodium 2-acrylamido-2-methylpropanesulfonate ATBS.Na, which has an X-ray powder diffraction pattern including peaks at the following positions: 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°; 47.6° 2θ angle, The water-soluble polymer contains 5 mol% to 100 mol% ATBS. At least 50 mol% of the ATBS in the water-soluble polymer is in crystalline form prior to polymerization. b) Inject the injected fluid into the underground formation; c) Using the injected fluid to propagate underground strata; d) Harvest mixtures of hydrous hydrocarbons.

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

3. The method according to claim 1, characterized in that... The water-soluble polymer contains 10 to 100 mol% of one or more anionic monomers, including monomers corresponding to the crystalline form of ATBS.Na.

4. The method according to claim 1, characterized in that... The water-soluble polymer contains only anionic monomer units and nonionic monomer units.

5. The method according to claim 1, characterized in that... The water-soluble polymer consists of acrylamide and ATBS, wherein 50 mol% of the ATBS is in the crystalline form of ATBS.Na prior to polymerization.

6. The method according to claim 1, characterized in that... The filtration ratio of the water-soluble polymer is less than 1.5.

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