METHOD FOR INJECTING AN AQUEOUS HOMOPOLYMER SOLUTION
By preparing aqueous polymer solutions on-site using modular units and solid monomers, the method addresses logistical and environmental challenges of polymer injection, achieving cost-effective and efficient hydrocarbon extraction and hydraulic fracturing.
Patent Information
- Authority / Receiving Office
- BR · BR
- Patent Type
- Applications
- Current Assignee / Owner
- S P C M SA
- Filing Date
- 2024-03-13
- Publication Date
- 2026-07-14
AI Technical Summary
Existing methods for injecting sodium, potassium, or ammonium 2-acrylomido-2-methylpropanesulfonate polymers into underground formations for hydrocarbon extraction and hydraulic fracturing are costly due to long-distance logistics, energy-intensive polymer dissolution, and high carbon footprint, with powder form requiring expensive facilities and energy-consuming drying processes.
A method for preparing aqueous solutions of these polymers on modular units near the injection sites, involving preparation, synthesis, and dilution steps, using solid monomers like 2-acrylamido-2-methylpropanesulfonic acid, which are non-toxic and stable, allowing continuous production with reduced logistical costs and carbon footprint.
This approach significantly reduces logistical costs and carbon footprint while enabling flexible deployment at various field conditions, ensuring efficient polymer injection with minimal energy consumption and avoiding the need for high-risk facilities.
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Abstract
Description
/ 19 METHOD FOR INJECTING AN AQUEOUS HOMOPOLYMER SOLUTION Field of invention
[001] The invention relates to a method for injecting an aqueous solution of sodium, potassium or ammonium 2-acrylomido-2-methylpropanesulfonate homopolymer into an underground formation for assisted extraction of hydrocarbons (oil and / or gas) or hydraulic fracturing.
[002] More specifically, the method refers to the field of polymer solution preparation in fields in modular units for its direct injection into the underground formation. Previous technique
[003] The Applicant's patent applications FR2302305, FR2302307 and FR2302310 highlight the interest in injecting saline solutions of sodium or potassium 2-acrylamido-2-methylpropanesulfonate polymer in crystalline form into underground formations for assisted recovery of hydrocarbons (oil and / or gas) or hydraulic fracturing.
[004] For oil or gas assisted recovery techniques, these polymers have improved properties in terms of filterability and chemical and thermal stability.
[005] For hydraulic fracturing, synthetic polymers based on sodium or potassium 2-acrylomido-2-methylpropanesulfonate in hydrated form allow for a very high friction reduction effect, while also ensuring an improved viscosifying effect in a saline solution (brine). Furthermore, the good solubility of the polymer in the fracturing fluid, combined with its anionic sulfonic character, prevents its adsorption onto the rock, which induces a recovery of conductivity and, therefore, an increase in the yield of hydrocarbon production (oil and / or gas).
[006] However, the synthesis of 2-acrylomido-2-based polymers Petition 870250100014, dated 10 / 31 / 2025, page 6 / 30 / 19 Sodium or potassium methylpropanesulfonate in hydrated form is made in manufacturing locations that are far from the injection wells that lead to these underground formations and, because of this, involves expensive logistics that consume a lot of energy to send the polymers to the hydrocarbon development fields.
[007] The physical form of the polymer that allows for the highest mass concentration of active material to supply fields for EOR or hydraulic fracturing is powder. However, this physical form involves specific dissolution units (PSU: Polymer slicing unit, maturation tanks, see WO 2008 / 071808), which are expensive and consume a lot of energy.
[008] Furthermore, the powder comes from a gel polymerization method, which involves a drying operation of the polymer gel to transform it into powder (US patent 5633329). Typically, it is necessary to evaporate 1 to 5 volumes of water for 1 volume of powder, which involves increasing water and energy consumption and therefore increasing the product's carbon footprint. Summary of the invention
[009] The Applicant has thus developed a method for preparing solutions of sodium or potassium or ammonium 2-acrylomido-2-methylpropanesulfonate and / or their salts based on modular units, in order to be able to carry out all preparation steps in fields in the vicinity of the underground formations to be developed.
[0010] This method includes (1) the preparation of sodium, potassium or ammonium 2-acrylomido-2-methylpropanesulfonate in hydrated form at a first location, (2) the synthesis of the polymer and the preparation of a concentrated polymer solution at a second location, and finally, (3) the dilution of this solution for injection into the underground formation at a third location.
[0011] This method allows for the continuous flow production of the required quantity of injectable solution. Furthermore, it allows for a reduction Petition 870250100014, dated 10 / 31 / 2025, page 7 / 30 / 19 considerably reduces logistical costs (transport, polymer dissolution) with a low water and carbon footprint (no drying) and can be transposed to any field and under any field conditions (salinity, hardness, temperature, etc.) without the need for facilities classified as high risk (chemical).
[0012] The only monomer to be shipped and possibly stored at the first location is 2-acrylamido-2-methylpropanesulfonic acid (AMPS) or one of its salts. This monomer, unlike monomers such as acrylonitrile, acrylamide, or acrylic acid, has the advantage of being in solid form and therefore not posing a risk of leakage or spillage. Furthermore, it is non-toxic (CMR) and remains stable in the solid state according to temperature (it is not temperature sensitive). Finally, another advantage of AMPS, or one of its salts, over acrylamide is that it can be polymerized at higher concentrations without the need for pre-cooling, being less exothermic, which generates energy gains and makes the claimed method transferable to any location, including dry areas or those with seasonal water stress.
[0013] By way of illustration, 1 volume of acrylamide and / or acrylic acid needs to be polymerized in the presence of at least 3 volumes of water and with prior cooling to 0°C, while AMPS or one of its salts needs only 1 to 2 volumes of water with polymerization starting in solution at room temperature. Presentation of the invention
[0014] More specifically, the invention relates to a method for injecting an aqueous solution of homopolymer P of sodium or potassium or ammonium 2-acrylomido-2-methylpropanesulfonate and / or their salts, the homopolymer P having a weight-average molecular weight greater than 1 million daltons, the aqueous solution of homopolymer P being injected into an underground formation for assisted hydrocarbon extraction. Petition 870250100014, dated 10 / 31 / 2025, page 8 / 30 / 19 (oil and / or gas) or hydraulic fracturing, said method comprising the following successive steps: - at location A: * preparation in mobile unit U1 of sodium or potassium or ammonium 2-acrylamido-2-methylpropanesulfonate in crystalline form (AMPS.S), sodium 2-acrylamido-2-methylpropanesulfonate in crystalline form with an X-ray diffraction pattern in powder 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 degrees, potassium 2-acrylamido-2-methylpropanesulfonate in crystalline form with an X-ray diffraction pattern in powder comprising peaks at 13.1°; 14.4°; 16.3°; 19.8°; 23.5°; 24.3°; 26.9°; 27.6°; 29.3°; 30.6°; 31.6°; 34.3°; 36.1°; 41.7°; 44.6°; 46.7°, degrees 2-theta, 2-acrylamido-2-methylpropanesulfonate ammonium in crystalline form with a powder X-ray diffraction pattern comprising peaks at 10.1°; 13.1°; 13.2°; 17.5°; 15.6°; 18.1°; 19.5°; 20.0°; 21.4°; 22.8°; 23.6°; 24.8°; 25.1°; 25.8°; 26.2°; 27.4°; 28.1°; 29.4°; 30.2°; 30.8°; 32.0°; 32.9°; 33.2°; 33.9°; 34.4°; 35.0°; 36.2°; 37.7°; 38.8°; 39.6°; 40.4°; 41.4°; 41.9°; 42.8°; 43.5°; 44.8°; 45.5°; 45.7°; 46.5°; 47.0°; 47.4°, 2-theta degrees, * collection of an aqueous solution S1 of sodium or potassium or ammonium 2-acrylamido-2-methylpropanesulfonate of AMPS.OS, obtained from the purge of the AMPS.S preparation in the mobile unit U1, - at location A': * preparation in a mobile unit U3 of a homopolymer P by gel polymerization of an aqueous solution S3 of AMPS.S, * dissolution in a mobile unit U4 of polymer P in saline solution SS1 containing at least 1 g / L of alkaline and / or alkaline earth salts in water to obtain a solution SM of polymer P, Petition 870250100014, dated 10 / 31 / 2025, page 9 / 30 / 19 * transfer of the SM solution from location A' to location B, at location B: * Dilution in a mobile unit U5 of at least a factor of 4 and at most a factor of 60 of the SM solution by a saline solution SS2 containing at least 1 g / L of alkaline and / or alkaline-earth salts in water to obtain an aqueous solution SF containing less than 0.6% by weight of polymer P, * Injection of the SF solution into the underground formation.
[0015] In this process: - at site A: polymerization (in solution, example of method: US document 2013090425) in a U2 unit of the S1 solution of AMPS.OS collected in the mobile unit U1 to obtain an aqueous polymer solution S2 P', - Transfer of solution S2 via piping from unit U2 at location A to mobile unit U3 at location A'. - at site A': preparation in mobile unit U3, prior to the polymerization of AMPS.S, of a composition CA' comprising solution S3 of AMPS.S and at least part of solution S2 of polymer P', the mass ratio [P'] / [AMPS.S] being between 0.05 and 0.20, with [P'] being the weight concentration of polymer P' in composition CA' and [AMPS.S] the weight concentration of AMPS.S in composition CA'.
[0016] The value ranges include the lower and upper limits. Thus, the value ranges between 0.1 and 1.0 and from 0.1 to 1 include the values 0.1 and 1.0.
[0017] In general, the uncertainty of the peaks in powder X-ray diffraction patterns is usually on the order of + / - 0.1°.
[0018] According to the present invention, the weight-average molecular weight of polymer P is determined by measuring the intrinsic viscosity. The intrinsic viscosity can be measured by methods known to a person skilled in the art and can, in particular, be calculated from values of Petition 870250100014, dated 10 / 31 / 2025, page 10 / 30 / 19 reduced viscosity for different concentrations by a graphical method that consists of plotting the reduced viscosity values (on the y-axis) according to the concentrations (on the x-axis) and extrapolating the curve to a zero concentration. The intrinsic viscosity value is read on the y-axis or using the least squares method. Then, the weight-average molecular weight can be determined by the famous Mark-Houwink equation: [η] = KMa [η] represents the intrinsic viscosity of the polymer determined by the solution viscosity measurement method. K represents an empirical constant, M represents the molecular weight of the polymer, α represents the Mark-Houwink coefficient, and α and K depend on the specific polymer-solvent system. Tables known to a specialist in the field provide values of α and K according to the polymer-solvent system.
[0019] Location A is advantageously a location comprising at least one mobile storage unit, at least one mobile mixing unit, and at least one mobile filtration unit. Thus, location A makes it advantageously possible to have clean water for the radical polymerization of APMS.S (e.g., water from an industrial water treatment method and / or rainwater).
[0020] The preparation of sodium 2-acrylamido-2-methylpropanesulfonate in crystalline form is carried out according to the method described in patent application FR2302303.
[0021] The present invention also relates to a method for producing the crystalline form of the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid comprising at least the following successive steps: 1) mixture of 2-acrylamido-2-methylpropanesulfonic acid Petition 870250100014, dated 10 / 31 / 2025, page 11 / 30 / 19 with an aqueous solution of SANa-1 and at least one sodium salt, advantageously for at least 1 minute, in order to form an aqueous solution or an aqueous suspension of SANa-2; 2) distillation, at a pressure lower than atmospheric pressure, of the aqueous solution or aqueous suspension SANa-2 to form a suspension SNa-1; 3) Solid-liquid separation of the SNa-1 suspension and isolation of the SNa-1 suspension crystals obtained at the end of step 2) in the form of a CNa-1 composition.
[0022] The crystals obtained are in the crystalline form of the sodium salt of 2-acrylamido-2-methylpropanesulfonic acid.
[0023] “Sodium salt(s)” in aqueous solution or suspension SA2 should be understood as meaning at least one inorganic salt, for example sodium hydroxide, sodium carbonate, sodium bicarbonate or mixtures thereof.
[0024] The preparation of potassium 2-acrylamido-2-methylpropanesulfonate in crystalline form is carried out according to the method described in patent application FR2302310.
[0025] The present invention also relates to a method for producing the crystalline form of the potassium salt of 2-acrylamido-2-methylpropanesulfonic acid comprising at least the following successive steps: 1) Mixing 2-acrylamido-2-methylpropanesulfonic acid with an aqueous solution SAK-1 and at least one potassium salt, advantageously for at least 1 minute, in order to form an aqueous solution or an aqueous suspension SAK-2; 2) Distillation, at a pressure lower than atmospheric pressure, of the aqueous solution or aqueous suspension SAK-2 to form a suspension SK-1; 3) Solid-liquid separation of the suspension SK-1 and isolation of the crystals of the suspension SK-1 obtained at the end of step 2) in the form of a composition CK-1. Petition 870250100014, dated 10 / 31 / 2025, page 12 / 30 / 19
[0026] The crystals obtained are in the crystalline form of the potassium salt of 2-acrylamido-2-methylpropanesulfonic acid.
[0027] “Potassium salt(s)” in aqueous solution or suspension SAk-2 should be understood as meaning at least one inorganic salt, for example potassium hydroxide, potassium carbonate, potassium bicarbonate or mixtures thereof.
[0028] The preparation of ammonium 2-acrylamido-2-methylpropanesulfonate (CH2=CH-C(=O)-NH-C(CH3)2-CH2-S(=O)2O-+NH4) in crystalline form is carried out according to a process comprising at least the following successive steps: 1) Piping gaseous ammonia into a solution or suspension of 2-acrylamido-2-methylpropanesulfonic acid to form an SNH4-1 solution; 2) Optionally evaporating the water (advantageously under atmospheric pressure or vacuum); 3) Cooling the aqueous SNH4-1 solution to obtain an SNH4-2 suspension of ammonium 2-acrylamido-2-methylpropanesulfonate crystals; 4) Solid-liquid separation of the SNH4-2 suspension and isolation of the crystals from the SNH4-2 suspension obtained at the end of step 3) in the form of a Cnh4-i composition.
[0029] The mobile unit U1 advantageously comprises at least one mixing subunit and at least one filtration subunit. These subunits are known to a person skilled in the art and may correspond to those described in document WO 2018 / 172676 and patent application FR 2302303.
[0030] This U1 mobile unit is a relocatable modular unit that can be transported by truck or rail.
[0031] This mobile unit U1 contains a mobile storage subunit for collecting the AMPS.OS solution S1. This solution S1 comes from the drainage of the AMPS.S preparation and is therefore composed of a mixture of the filtrates and the solutions for washing the crystals. Petition 870250100014, dated 10 / 31 / 2025, page 13 / 30 / 19 AMPS.S (crystalline form of the AMPS salt). The mobile storage subunit is preferably a tank.
[0032] Preferably, AMPS.S is prepared by purifying powdered 2-acrylamido-2-methylpropanesulfonic acid previously stored at site A in a mobile storage unit located in the vicinity of mobile unit U1 (and therefore distinct from the mobile storage subunit). This storage unit is replenished by rail or truck transport from 2-acrylamido-2-methylpropanesulfonic acid production sites, which may be several tens or hundreds of kilometers away from the site. The mobile storage unit in the vicinity of mobile unit U1 may have any shape and orientation. It may be, for example, cylindrical or rectangular and oriented horizontally or vertically. The volume and dimensions are limited only by the condition that the storage units can be moved.
[0033] Advantageously, 2-acrylamido-2-methylpropane sulfonic acid in powder form stored in the mobile storage unit at site A was previously obtained at its production site by a reaction between acrylonitrile, fuming sulfonic acid and isobutylene containing less than 1000 ppm of butadiene and less than 100 ppm of butene (document WO 201746546).
[0034] Powder X-ray diffraction patterns for AMPS.S are conventionally made by X-ray crystallography, X-ray radiocrystallography, or diffractometry. An example of equipment is a Rigaku Miniflex II diffractometer equipped with a copper source.
[0035] Advantageously, location A' is a location that allows for the installation of at least one mobile storage unit, at least one mobile polymerization unit, and at least one mobile dilution unit. Thus, location A' advantageously makes it possible to have water. Petition 870250100014, dated 10 / 31 / 2025, p. 14 / 30 / 19 clean for radical polymerization of APMS.S (e.g., water from an industrial water treatment method and / or rainwater), but also lower quality water for the preparation of aqueous solutions (in particular, SS1 or SS2).
[0036] The U3 mobile unit is advantageously composed of at least one polymerization subunit, such as an inverted conical tubular reactor (inverted cone). Thus, the polymerization subunit makes it possible to discharge the polymer gel by applying air pressure to the gel surface or in the form of a tipper that discharges the gel mass causing the reactor to tip over. Advantageously, this U3 mobile unit also contains storage subunits for additives necessary for gel polymerization (generally, one storage unit per additive). These additives are, for example, initiators (oxidant / reductant, azos), polymerization regulators, enzymes (glucose oxidase). The polymerization additives and the gel polymerization conditions are known to a specialist in the field. The characteristics of each storage unit are adapted to the physicochemical properties and quantities of the different additives.The U3 mobile unit is a relocatable modular unit that can be transported by truck or rail.
[0037] Preferably, the polymerization of the S3 solution of AMPS.S in the CA' composition in the mobile unit U3 is carried out with an initial concentration (before mixing S2 and S3) of AMPS.S in the S3 solution greater than 20% by weight, even more preferably greater than 30% by weight, and even more preferably greater than 40% by weight. The initial concentration of AMPS.S in the S3 solution is advantageously less than 70% by weight.
[0038] Advantageously, the initial polymerization temperature is room temperature, i.e., between 15 and 30°C, and the final polymerization temperature of the S3 solution of AMPS.S in composition CA' in the mobile unit U3 is greater than 80°C. An expert in the field will know how to adapt the Petition 870250100014, dated 10 / 31 / 2025, page 15 / 30 / 19 polymerization conditions to reach that temperature.
[0039] Preferably, the gel polymerization of the S3 solution of AMPS.S in composition CA' within the mobile unit U3 is initiated in the presence of glucose oxidase. Radical polymerization requires the absence of any traces of oxygen in the polymerization environment. The glucose oxidase aims to deoxygenate the S3 solution. The use of bubbling with inert gases, such as nitrogen or argon, is therefore generally unnecessary in the presence of glucose oxidase. This further reduces the need to locally produce energy-intensive and atmospheric-emitting inert gases, sources of pollution.
[0040] The polymer P obtained from gel polymerization in mobile unit U3 is dissolved in a mobile unit U4 in saline solution SS1 containing at least 1 g / L of alkaline and / or alkaline-earth salts in water to obtain a polymer P solution SM.
[0041] The U4 mobile unit is a relocatable modular unit that can be transported by truck or rail.
[0042] In a preferred embodiment, at the end of the preparation of polymer P by gel polymerization of the S3 solution of AMPS.S in composition CA' in mobile unit U3, the polymer P gel obtained is granulated in a granulation subunit to obtain polymer P gel chunks, which are dissolved directly in solution SS1 to obtain solution SM in mobile unit U4.
[0043] The size of the aqueous polymer P gel pieces at the end of granulation is not specifically limited. In one embodiment of the invention, the granulated aqueous polyacrylamide gel pieces advantageously have a size such that at least two dimensions (length and diameter in the case of pieces in the form of cylindrical granules) are no larger than 1 cm, preferably no larger than 0.5 cm. Preferably, all three dimensions (width, length, and height in the case of cylindrical granules) are also no larger. Petition 870250100014, dated 10 / 31 / 2025, p. 16 / 30 / 19 of parallelepiped-shaped pieces) of aqueous polyacrylamide gel pieces should not be larger than 1 cm, preferably no larger than 0.5 cm. A lower limit for aqueous polyacrylamide gel pieces is not necessary, as the smaller the pieces, the more easily the polymer dissolves. Generally, aqueous polyacrylamide gel pieces can be of a size such that all three dimensions are as small as 0.1 cm. Frequently, aqueous polyacrylamide gel pieces tend to have three dimensions, each between 0.1 cm and 0.5 cm.
[0044] In principle, any type of granulation medium can be used to granulate water-soluble polymer gel into smaller pieces. Examples of suitable media include cutting devices such as cutters or perforated plates, crushers, kneaders, static or dynamic mixers, or water jets. A person skilled in the art will choose the appropriate media and their conditions of use to obtain gel pieces of predetermined sizes and shapes.
[0045] Advantageously, the polymer P gel pieces obtained at the end of granulation are added directly to a dissolution tank of the mobile unit U4. In this case, dissolution in the saline solution SS1 is accelerated by means of a stirring blade. The gel pieces can also be dissolved within a conduit equipped with, or not equipped with, static or dynamic mixers. The combination of a conduit and a dissolution tank is also possible. Advantageously, the polymer P gel pieces are not stored between granulation and dissolution.
[0046] Advantageously, between mobile units U3 and U4, the polymer P in gel form is transported by a helical conveyor to be granulated in a granulation subunit.
[0047] Preferably, the saline solution SS1 or SS2 contains between 1g / L and 350g / L of alkaline and / or alkaline-earth salts in water, even more Petition 870250100014, dated 10 / 31 / 2025, page 17 / 30 / 19 preferably between 10g / L and 300g / L.
[0048] Preferably, the saline solution SS1 or SS2 is drawn directly into location A. As an example, this SS1 or SS2 solution could be seawater extracted from an offshore oil platform.
[0049] The saline solution SS1 can optionally be prepared within the mobile unit U4 in a dissolution tank and / or in a pipeline equipped with static and / or dynamic mixers, by adding the necessary quantities of salts to the water. The SS1 or SS2 solution preferably contains sodium (alkaline salt) and / or calcium (alkaline-earth salt), for example, a salt chosen from calcium chloride, calcium bromide, sodium chloride and mixtures thereof.
[0050] Advantageously, the mobile unit U4 comprises at least one dissolution subunit, for example, a tank fitted with an agitator blade and / or a conduit fitted with mixers. Advantageously, it also comprises a tank for storing the saline solution SS1.
[0051] During the preparation of the SS1 or SS2 solution, various compounds known to a specialist in the field may be added, such as those cited in document SPE 152596. Thus, the SS1 or SS2 solution may comprise, for example: - Clay anti-swelling agents, such as potassium chloride or choline chloride, and / or - Biocides to prevent the growth of bacteria, particularly sulfate-reducing bacteria, which can form viscous masses that reduce passage surfaces. Examples include glutaraldehyde, which is the most commonly used, or even formaldehyde or isothiazolinones, and / or - Oxygen reducers, such as ammonium bisulfite, to prevent the destruction of other components by oxidation and corrosion of the injection tubes, and / or Petition 870250100014, dated 10 / 31 / 2025, page 18 / 30 / 19 - Anti-corrosion additives to protect the pipes from oxidation by residual amounts of oxygen, with N,N-dimethylformamide being preferred, and / or - Lubricants, such as petroleum distillates, and / or - Iron chelating agents, such as citric acid, EDTA (ethylenediaminetetraacetic acid), phosphonates, and / or - Antiscaling agents, such as phosphates, phosphonates, polyacrylates or ethylene glycol.
[0052] For this U4 mobile unit, no treated water for polymerization is required to prepare the SS1 solution. This unit can use oil production water (conditioned for injection) or aquifer water.
[0053] Location B is advantageously a location that allows the installation of at least one mobile storage unit and at least one mobile dilution unit. Location B, in particular, makes it possible to inject a fluid into an underground formation to extract hydrocarbons (oil and / or gas).
[0054] The U5 mobile unit is advantageously a relocable unit comprising at least one dilution subunit, for example a tank fitted with a stirring blade and / or a conduit fitted with static and / or dynamic mixers. Optionally, the U5 mobile unit comprises a tank for storing the SM solution.
[0055] The U5 mobile unit is a relocatable modular unit that can be transported by truck or rail.
[0056] Inside this mobile unit U5, the saline solution SM is diluted by a factor of at least 4 and at most a factor of 60 by the saline solution SS2 to obtain a solution SF containing less than 0.6% by weight of polymer P. As an example, for a solution containing 60% by weight of polymer P, a dilution by a factor of 4 corresponds to obtaining a Petition 870250100014, dated 10 / 31 / 2025, page 19 / 30 / 19 solution containing 15% by weight of polymer P.
[0057] Preferably, the SF solution contains between 0.01% and 0.4% by weight of polymer P, even more preferably between 0.02% and 0.3% by weight of polymer P.
[0058] As for mobile unit U4, saline solution SS2 can be prepared within mobile unit U5, for example, in a dissolving tank, by adding the required amounts of salts to water or by directly extracting the SS2 solution within location B.
[0059] After optionally being stored in a storage tank, the SF solution is injected into the underground formation to extract hydrocarbons (oil and / or gas). Hydrocarbon recovery is achieved either by sweeping the underground formation (conventional assisted hydrocarbon extraction) or by the natural pressure of the hydrocarbons after a hydraulic fracturing operation (unconventional extraction).
[0060] Thus, the injection of the SF solution into the underground formation is followed by a hydrocarbon recovery step by extraction assisted by sweeping the underground formation using the SF solution, or by a hydrocarbon recovery step by hydraulic fracturing of the underground formation using the SF solution.
[0061] According to a preferred embodiment, the injection method of the invention is performed with the locations A and A' overlapping or contiguous. In other words, in this configuration, the 2 locations become one.
[0062] The injection method of the invention comprises the following steps: - at site A: polymerization (in solution, example of method: US document 2013090425) in a U2 unit of the S1 solution of AMPS.OS collected in the mobile unit U1 to obtain an aqueous polymer solution S2 P', Petition 870250100014, dated 10 / 31 / 2025, page 20 / 30 / 19 - Transfer of solution S2 via piping from unit U2 at location A to mobile unit U3 at location A'. - at site A': preparation in mobile unit U3, prior to the polymerization of AMPS.S, of a composition CA' comprising solution S3 of AMPS.S and at least part of solution S2 of polymer P', the mass ratio [P'] / [AMPS.S] being between 0.05 and 0.20, with [P'] being the weight concentration of polymer P' in composition CA' and [AMPS.S] the weight concentration of AMPS.S in composition CA'.
[0063] The transfer of the S1 AMPS.OS solution from the storage subunit of mobile unit U1 to unit U2 is preferably done through a conduit (tube).
[0064] The polymerization of AMPS.OS solution S1 in unit U2 is a solution polymerization known to a person skilled in the art to obtain a polymer P' with a weight-average molecular weight advantageously between 500 and 500000 daltons. Adding polymer P' solution S2 to solution S3 is preferably done before the addition of redox and / or thermal initiators and / or glucose oxidase.
[0065] The U2 unit is a relocable modular unit that can be transported by truck or rail and consists of at least one polymerization subunit, for example, a tank fitted with an agitator blade.
[0066] Depending on the distances between locations A' and B, the transfer of the SM solution from location A' to location B is done via pipelines or transport units.
[0067] For example, the distances between locations A' and B could be between 10 and 3000km, or between 10 and 1500km, or between 20 and 500km, or also between 30 and 300km.
[0068] The pipes that ensure the transfer of the SM solution between locations A' and B are preferably rigid and may include mixers. Petition 870250100014, dated 10 / 31 / 2025, p. 21 / 30 / 19 static.
[0069] For the transport of the SM solution between locations A' and B, a suitable transport unit is used. The transport unit may have a volume from 1m3 to 40m3, in particular from 5m3 to 40m3, preferably from 10 to 30m3, for example from 20m3 to 30m3 or from 15 to 25m3. Examples of suitable transport units include ships comprising at least one opening or tank containers.
[0070] The transport of the SM solution between locations A' and B can be done by any type of transport suitable for transporting the transport unit, for example, trucks, cars or ships.
[0071] The term transport unit means one or more advantageously distinct transport units, such as containers, for example, ISO containers or loose intermediate containers, which are loaded onto suitable means of transport, for example, trailers, container wagons or ships. The means of transport may carry a single transport unit or a plurality of transport units. The term transport unit also includes transport units in which the transport compartment is temporarily or permanently attached to the means of transport, such as tanks or tank wagons.
[0072] In one embodiment, transport is carried out by trucks. The transport unit may also be attached to a truck. In one embodiment, the transport unit may be an ISO tank container.
[0073] In one embodiment, tanks may be mounted on a truck. In one embodiment, the tank comprises an outlet opening at the rear end of the truck and, to facilitate removal of the contents, the tank may be tilted. In another embodiment, the tank comprises an outlet opening on the underside of the tank. In addition, the tank may comprise a cone at the bottom of the tank and the outlet opening is located at the lower end. Petition 870250100014, dated 10 / 31 / 2025, page 22 / 30 / 19 of the cone. Filling the transport unit with the SM solution can be done by pumping the SM solution into the transport unit.
[0074] The transport time, i.e., the transport time of the transport unit filled with polymer P SM solution, can vary greatly depending on the distance between locations A' and B. It can range from a few minutes to several days, for example, from 1 hour to 28 days, in particular from 2 hours to 14 days, in particular from 5 hours to 7 days. In one embodiment of the invention, a homogenization step, such as that described below, can be performed during transport. In one embodiment, the transport unit, for example a truck, may comprise a rotating drum that allows homogenization to be performed. In some embodiments, the transport unit may comprise a circulation circuit equipped with a pump and, optionally, mixing units, for example, static mixers, so that the polymer P SM solution can be circulated during transport.
[0075] Advantageously, the SM solution of polymer P at location A' is stored in a maturation and storage unit before being transferred to location B. This maturation and storage unit is advantageously made up of one or more tanks in series equipped with agitation blades. Figures
[0076] Figure 1 represents the present invention according to which the AMPS.S monomer is polymerized in the presence of polymer P'. Description of the figures
[0077] The device in Figure 1 comprises: - a location A including: * preparation in a mobile unit U1 of AMPS.S, * collection of aqueous solution S1 of AMPS.OS, resulting from the drainage of the AMPS.S preparation, Petition 870250100014, dated 10 / 31 / 2025, page 23 / 30 / 19 - a location A' including: * the preparation in a mobile unit U3 of a homopolymer P by gel polymerization of an aqueous solution S3 of AMPS.S in a composition CA', * the preparation in a mobile unit U3, prior to the polymerization of AMPS.S, of a composition CA' containing the S3 solution of AMPS.S and at least part of the S2 solution of polymer P', * the dissolution in a mobile unit U4 of polymer P in saline solution SS1 to obtain an SM solution of polymer P, * the transfer of the SM solution from location A' to location B, * the polymerization (in solution) in a unit U2 of the S1 solution of AMPS.OS to obtain an aqueous solution S2 of polymer P', - the transfer of solution S2 from unit U2 at location A to mobile unit U3 at location A', - Location B including: * dilution in a U5 mobile unit of the SM solution with a SS2 saline solution to obtain an SF solution containing less than 0.6% by weight of P polymer, * injection of the SF solution into the underground formation. Petition 870250100014, dated 10 / 31 / 2025, p. 24 / 30
Claims
1 / 4 CLAIMS 1. Method for injecting an aqueous solution of homopolymer P of sodium, potassium or ammonium 2-acrylamide-2-methylpropanesulfonate and / or its salts, the homopolymer P having a weight-average molecular weight greater than 1 million daltons, the aqueous solution of homopolymer P being injected into an underground formation for assisted hydrocarbon extraction or hydraulic fracturing, characterized in that said method comprises the following successive steps: - at a location A: * preparation in mobile unit U1 of sodium or potassium or ammonium 2-acrylamide-2-methylpropanesulfonate in crystalline form (AMPS.S), sodium 2-acrylamide-2-methylpropanesulfonate in crystalline form with a powder X-ray diffraction pattern comprising peaks at 11.70°; 12.20°; 13.2°; 13.5°; 15.60°; 16.80°; 17.80°; 18.5°; 19.1°; 20.6°; 21.4°; 23.3°; 25.1°; 25.8°; 26.9°; 29.10°; 29.50°; 31.0°; 33°; 33.6°; 34.4°; 35.2°; 35.9°; 37.1°; 38.4°; 39.6°; 41.10°; 42.90°; 45.10°; 46.0°; 47,2°; 47.6°, 2-theta degrees, potassium 2-acrylamido-2-methylpropanesulfonate in crystalline form with a powder X-ray diffraction pattern comprising peaks at 13.10°; 14.4°; 16.3°; 19.8°; 23.50°; 24.3°; 26.9°; 27.6°; 29.3°; 30.6°; 31.6°; 34.3°; 36.1°; 41.7°; 44.6°; 46.7°, degrees 2-theta, ammonium 2-acrylamido-2-methylpropanesulfonate in crystalline form with a powder X-ray diffraction pattern comprising peaks at 10.10°; 13.10°; 13.2°; 17.5°; 15.60°; 18.10°; 19.50°; 20.0°; 21.4°; 22.8°; 23.6°; 24.8°; 25.1°; 25.8°; 26.2°; 27.4°; 28.10°; 29.4°; 30.2°; 30.8°; 32.0°; 32.9°; 33.2°; 33.9°; 34.4°; 35.0°; 36.2°; 37.7°; 38.8°; 39.6°; 40.4°; 41.4°; 41.9°; 42.8°; 43.5°; 44.8°; 45.5°; 45.7°; 46.5°; 47.0°; 47.4°, 2-theta degrees, * collection of an aqueous solution S1 of sodium or potassium or ammonium 2-acrylamido-2-methylpropanesulfonate AMPS.OS, coming from the purge of the preparation of AMPS.S in mobile unit U1, Petition 870250100020, dated 10 / 31 / 2025,page. 6 / 13 2 / 4 * Polymerization in a U2 unit of the S1 solution of AMPS.OS collected in the mobile unit U1 to obtain an aqueous solution S2 of polymer P', * Transfer via piping of the S2 solution from the U2 unit at location A to a mobile unit U3 at location A', - at location A': * Preparation in a mobile unit U3 of a composition CA' containing an S3 solution of AMPS.OS and at least part of the S2 solution of polymer P', the mass ratio [P'] / [AMPS.OS] being between 0.05 and 0.20, with [P'] weight concentration of polymer P' in composition CA' and [AMPS.OS] weight concentration of AMPS.OS in composition CA', * Preparation in the mobile unit U3 of a homopolymer P by gel polymerization of aqueous solution S3 of AMPS.OS in composition CA', * Dissolution in a mobile unit U4 of polymer P in saline solution SS1 containing at least 1 g / L of Alkaline and / or alkaline earth salts in water to obtain a polymer SM solution P, * transfer of the SM solution from location A' to location B,at location B: * dilution in mobile unit U5 of at least a factor of 4 and at most a factor of 60 of the SM solution by a saline solution SS2 containing at least 1 g / L of alkaline and / or alkaline-earth salts in water to obtain an SF solution containing less than 0.6% by weight of polymer P, * injection of the SF solution into the underground formation.
2. Method according to claim 1, characterized in that locations A and A' overlap or are contiguous.
3. A method according to any of the preceding claims, characterized in that the transfer of the SM solution from location A' to location B is done through pipelines or transport units.
4. Method according to any of the preceding claims, characterized in that AMPS.S is prepared by Petition 870250100020, dated 10 / 31 / 2025, page 7 / 13 3 / 4 purification of 2-acrylamido-2-methylpropane sulfonic acid previously stored at location A in a mobile storage unit.
5. Method according to any of the preceding claims, characterized in that at the end of the preparation of polymer P by gel polymerization of the S3 solution of AMPS.S in composition CA' in mobile unit U3, the polymer P gel obtained is granulated in a granulation unit to obtain polymer P gel pieces, which are dissolved directly in saline solution containing at least 1 g / L of alkaline and / or alkaline-earth salts to obtain the SM solution in mobile unit U4.
6. A method according to any of the preceding claims, characterized in that the polymerization of polymer P in the mobile unit U3 is initiated in the presence of glucose oxidase.
7. A method according to any of the preceding claims, characterized in that the SM solution at location A' is stored in a maturation and storage unit before being transferred to location B.
8. A method according to any of the preceding claims, characterized in that the polymerization of the S3 solution of AMPS.S in the CA' composition in the mobile unit U3 is carried out with an initial concentration of AMPS.S in the S3 solution greater than 20% by weight.
9. A method according to any of the preceding claims, characterized in that the final polymerization temperature of the S3 solution of AMPS.S in composition CA' in the mobile unit U3 is greater than 80°C.
10. Method according to any of the preceding claims, characterized in that the injection of the SF6 solution into the underground formation is followed by a hydrocarbon recovery step by sweep-assisted extraction of the underground formation using the SF6 solution. Petition 870250100020, dated 10 / 31 / 2025, page 8 / 13 4 / 4 11. A method according to any of the preceding claims, characterized in that the injection of the SF6 solution into the underground formation is followed by a hydrocarbon recovery step by hydraulic fracturing of the underground formation using the SF6 solution.
12. Method according to any one of claims 3 or 5, characterized in that the polymer P' has an average molecular weight between 500 and 500,000 Daltons. Petition 870250100020, dated 10 / 31 / 2025, page 9 / 13