A composition, its preparation method and its application

Abstract

This invention provides a composition, its preparation method, and its application. The composition comprises a fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, a polymeric product of acrylamide, and a high molecular weight polymer dispersant, and can be used as an acidification retarder.

Description

Technical Field

[0001] This invention belongs to the field of oilfield acidizing and production enhancement technology, and particularly relates to a composition, its preparation method and application. Background Technology

[0002] Matrix acidizing, also known as conventional acidizing or unblocking acidizing, refers to an acidizing technique that injects acid into the formation under conditions where the bottom hole pressure is lower than the reservoir rock fracturing pressure. This process removes damage near the wellbore and restores reservoir productivity. Because matrix acidizing is a non-intrusive technique, the acid primarily flows within rock pores and natural fractures, reacting in pores with good permeability. When blockages and some rock react rapidly with the acid, the rock walls are quickly dissolved in the direction of stronger reactivity, forming acid-etched pores. These pores become the main channels for improving reservoir permeability. Currently, the acid systems used in matrix acidizing include conventional acid systems, thickened acid systems, gelled acid systems, and diverting acid systems. Specific details and existing problems are as follows:

[0003] (1) Conventional acid fracturing system: Conventional acid fracturing technology refers to the process technology of fracturing the formation using only ordinary hydrochloric acid. No sand or pre-flush fluid is added during construction, and no special flowback technology is used. Ordinary hydrochloric acid is both the liquid that opens formation fractures and the liquid that reacts with the formation. Due to poor control of acid filtration, the acid-rock reaction rate is fast, and the acid etching distance is relatively short, generally between 15 and 30 meters, making it mainly suitable for severely damaged high-permeability reservoirs. For low-pressure oil wells and low-permeability formations, the residual acid after acidification is difficult to flow back, easily leading to secondary pollution and affecting the acidification effect. Furthermore, the acid-rock reaction rate of conventional acid fracturing is too fast, and the acid is mainly consumed within a 0.5-meter radius near the wellbore, failing to remove deep blockages in the oil well.

[0004] (2) Thickened Acid System: Thickened acid refers to an acid system in which a non-crosslinked acid thickener is added to the acid solution to increase its viscosity. Thickened acid has a high viscosity, which can control filtration loss, increase fracture width and length, thereby slowing down the acid-rock reaction rate and increasing the penetration distance of the active acid; at the same time, it can reduce friction, increase the discharge rate during construction, and better achieve deep acidification. The optimal in-situ viscosity of thickened acid is 30 to 40 mPa·s, and the residual acid viscosity should generally be between 5 and 10 mPa·s to facilitate return and carry solid particles in the fractures, reducing secondary damage to the formation from the acid solution. In field applications, thickened acid is required to have good thermal stability, a small viscosity reduction rate for fresh acid, thorough gel breaking, and low viscosity of residual acid for easy return. The disadvantage of this technology is that the return of residual acid is incomplete. According to relevant analysis, only 30% to 45% of the injected polymer is returned after acidification treatment, leaving a considerable amount of polymer in the formation. Despite attempts to remove residual polymers, the results have been minimal.

[0005] (3) Gelatinizing Acid System: Gelatinizing acid is an acid system prepared by adding an acid gelling agent and additives to ordinary hydrochloric acid. Gelatinizing acid has advantages such as slowing down reaction, reducing filtration, and facilitating drainage. After the acid solution thickens, it restricts the convection between the acid solution and the rock, limiting hydrogen ion transfer to diffusion, thus effectively slowing down the reaction rate. Simultaneously, the crack width is proportional to the fluid viscosity; thickened acid opens wider cracks, thus reducing the acid-rock surface volume ratio. This reduces the acid consumption rate and increases the effective action distance of the active acid. Gelatinizing acid reduces H+ by adjusting the acid solution viscosity. + Mass transfer rate and reaction rate, but increased viscosity leads to increased friction, resulting in reduced pumping efficiency.

[0006] (4) Diverting acid system: The diverting acid uniform distribution acid fracturing technology mainly uses hydrochloric acid viscoelastic surfactant as the acid. After being injected into the formation, the surfactant can first enter the rock layer with higher permeability, and then penetrate into the rock layer with lower permeability, which has the function of temporary plugging and diversion of the rock layer. This technology is not only an improvement on acid fracturing technology, but also can improve the permeability of low permeability reservoirs and improve the stimulation effect of carbonate reservoirs. However, the high temperature diverting acid system usually uses erucic acid ammonium betaine, with an addition of more than 6%. In the gas well acidification process, the residual acid viscosity is often high, and the flowback is difficult, so a large amount of acidification mutual solvent needs to be added.

[0007] In summary, existing acid systems suffer from high viscosity, high construction friction, and insufficient formation damage. It is necessary to further reduce the viscosity of acid systems, explore new long-distance reaction acids, and develop new technologies and systems that can increase the volume of the modification process while being economical and effective. Summary of the Invention

[0008] The first aspect of the present invention provides a composition comprising a fluorinated unsaturated compound, acrylic acid, a polymer of 2-acrylamide-2-methylpropanesulfonic acid and acrylamide, and a polymeric dispersant.

[0009] According to a specific embodiment of the present invention, the amount of the fluorinated unsaturated compound is 0.5 to 2 parts by weight, the amount of the acrylic acid is 5 to 10 parts, the amount of 2-acrylamide-2-methylpropanesulfonic acid is 10 to 20 parts, the amount of acrylamide is 20 to 50 parts, and the amount of the polymer dispersant is 2 to 5 parts.

[0010] According to a specific embodiment of the present invention, the fluorinated unsaturated compound includes at least one of methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide, hexafluorobutyl methacrylate, hexafluorobutyl acrylate, and hexafluoroisopropyl methacrylate.

[0011] According to one specific embodiment of the present invention, the polymeric dispersant includes at least one of polyamine, polyethylene glycol, and octadecyl alcohol polyoxyethylene ether.

[0012] According to one specific embodiment of the present invention, the polyamine has a molecular weight of 500 to 25,000; and / or

[0013] The molecular weight of the polyethylene glycol is between 400 and 2000.

[0014] A second aspect of the present invention provides a method for preparing a composition as described in the first aspect of the present invention, comprising the following steps:

[0015] 1) The polymer dispersant and solvent are mixed to obtain a polymer dispersant solution;

[0016] 2) Mix the fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and the polymer dispersant, adjust the pH, and obtain a reactant solution;

[0017] 3) The reactant solution is reacted under the action of an initiator to form the polymerization product, thereby obtaining the composition.

[0018] According to a specific embodiment of the present invention, the amount of the polymer dispersant is 2 to 5 parts by weight, the amount of the fluorinated unsaturated compound is 0.5 to 2 parts, the amount of acrylic acid is 5 to 10 parts, the amount of 2-acrylamide-2-methylpropanesulfonic acid is 10 to 20 parts, and the amount of acrylamide is 20 to 50 parts.

[0019] and / or

[0020] The amount of solvent in the polymer dispersant solution is sufficient to dissolve or disperse the polymer dispersant, the fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and acrylamide; and / or

[0021] The total mass of the fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and acrylamide is 100%, and the initiator accounts for 0.2 to 0.3 wt%.

[0022] According to a specific embodiment of the present invention, in step 1), the solvent is water; and / or

[0023] In step 2), adjust the pH to 6 to 6.5; and / or

[0024] In step 3), the initiator is persulfate.

[0025] According to one specific embodiment of the present invention, the temperature of the reaction is 40 to 50°C; and / or the duration is not less than 6 hours.

[0026] The use of the composition according to the first aspect of the present invention or the composition prepared by the method according to the second aspect of the present invention as an acidification retarder.

[0027] The beneficial effects of this invention are:

[0028] To address the problems of high viscosity, high friction during construction, and insufficient formation damage in existing acid systems, this invention provides a composition, its preparation method, and its application. The composition comprises a fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, a polymeric product of acrylamide, and a high-molecular-weight polymer dispersant, serving as an acidification retarder. In this composition, acrylamide provides a reproducible monomer for polymerization, forming a water-soluble polymeric product. The addition of 2-acrylamide-2-methylpropanesulfonic acid during synthesis introduces sulfonic acid groups, enabling the composition to adsorb onto the rock surface during acidification. The high-molecular-weight polymer dispersant increases the solubility of the fluorinated unsaturated compound in the polymerization system, thereby improving polymerization efficiency. This facilitates the formation of a hydrophobic film and increases the number of fluorocarbon chains oriented on the rock surface during acidification, effectively reducing H₂O. + The diffusion process achieves deep acidification. Furthermore, the introduction of fluorine-containing unsaturated compounds during the preparation of the composition allows the backflow fluid to act as a gas-wetting reversal agent on the surface of tight sandstone after acid fracturing, effectively preventing water-locking during the development of tight sandstone gas reservoirs. Experimental results show that adding 3wt% of the composition to 20wt% HCl produces the following acid solution with the following viscosity and retarding effect: 1) Viscosity is only 1.1 to 2.5 cps; the lower viscosity helps reduce construction friction and enhances the injectability of the acid solution; 2) The average dissolution rate of the carbonate rock core column in the acid solution at 90℃ is 5.64 × 10⁻⁶. -4 Up to 7.13×10 -4 g / (cm 2 Compared with 20wt% HCl, the acid-rock reaction rate of the acid solution with the added composition is significantly reduced, with a good retardation effect, which meets the requirements for in-depth acidification. Attached Figure Description

[0029] Figure 1 The infrared spectrum of the composition prepared in Example 2;

[0030] Figure 2 The 1H NMR spectrum of the composition prepared in Example 2;

[0031] Figure 3 This is a rate-time curve of acid-rock reaction in a core column at 90℃. Detailed Implementation

[0032] The present invention will be further described below with reference to the embodiments. However, the embodiments of the present invention are merely illustrative examples and should not be construed as limiting the present invention under any circumstances.

[0033] The first aspect of the present invention provides a composition comprising a fluorinated unsaturated compound, acrylic acid, a polymer of 2-acrylamide-2-methylpropanesulfonic acid and acrylamide, and a polymeric dispersant.

[0034] According to a specific embodiment of the present invention, the amount of the fluorinated unsaturated compound is 0.5 to 2 parts by weight, the amount of the acrylic acid is 5 to 10 parts, the amount of 2-acrylamide-2-methylpropanesulfonic acid is 10 to 20 parts, the amount of the acrylamide is 20 to 50 parts, and the amount of the polymer dispersant is 2 to 5 parts.

[0035] According to a specific embodiment of the present invention, the amount of the fluorinated unsaturated compound is 1 to 1.5 parts by weight, the amount of the acrylic acid is 8 to 10 parts, the amount of 2-acrylamide-2-methylpropanesulfonic acid is 15 to 20 parts, the amount of the acrylamide is 25 to 45 parts, and the amount of the polymer dispersant is 2 to 5 parts.

[0036] According to a specific embodiment of the present invention, the fluorinated unsaturated compound includes at least one of methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide, hexafluorobutyl methacrylate, hexafluorobutyl acrylate, and hexafluoroisopropyl methacrylate.

[0037] According to one specific embodiment of the present invention, the polymeric dispersant includes at least one of polyamine, polyethylene glycol, and octadecyl alcohol polyoxyethylene ether.

[0038] According to one specific embodiment of the present invention, the polyamine has a molecular weight of 500 to 25,000; and / or

[0039] The molecular weight of the polyethylene glycol is 400 to 2000;

[0040] Preferably, the polyamine is at least one selected from PEI-500, PEI-600, PEI-1000, PEI-2500, PEI-7500, and PEI-25000; and / or

[0041] The polyethylene glycol is at least one selected from PEG-400, PEG-600, PEG-1000, and PEG-2000; and / or

[0042] The octadecyl alcohol polyoxyethylene ether is octadecyl alcohol polyoxyethylene (40) ether and / or octadecyl alcohol polyoxyethylene (100) ether.

[0043] According to one specific embodiment of the present invention, the polymeric dispersant comprises polyamines and / or octadecyl alcohol polyoxyethylene ether.

[0044] According to one specific embodiment of the present invention, the polyamine has a molecular weight of 600 to 7500;

[0045] Preferably, the polyamine is at least one of PEI-600, PEI-1000, PEI-2500 and PEI-7500;

[0046] and / or

[0047] The octadecyl alcohol polyoxyethylene ether is octadecyl alcohol polyoxyethylene (40) ether.

[0048] A second aspect of the present invention provides a method for preparing a composition as described in the first aspect of the present invention, comprising the following steps:

[0049] 1) The polymer dispersant and solvent are mixed to obtain a polymer dispersant solution;

[0050] 2) Mix the fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and the polymer dispersant, adjust the pH, and obtain a reactant solution;

[0051] 3) The reactant solution is reacted under the action of an initiator to form the polymerization product, thereby obtaining the composition.

[0052] According to a specific embodiment of the present invention, the amount of the polymer dispersant is 2 to 5 parts by weight, the amount of the fluorinated unsaturated compound is 0.5 to 2 parts, the amount of acrylic acid is 5 to 10 parts, the amount of 2-acrylamide-2-methylpropanesulfonic acid is 10 to 20 parts, and the amount of acrylamide is 20 to 50 parts.

[0053] and / or

[0054] The amount of solvent in the polymer dispersant solution is sufficient to dissolve or disperse the polymer dispersant, the fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and acrylamide; and / or

[0055] The total mass of the fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, and acrylamide is 100%, and the initiator accounts for 0.2 to 0.3 wt% by mass.

[0056] Preferably, the polymer dispersant solution accounts for 100% by mass, and the solvent accounts for 96 to 99 wt% by mass.

[0057] According to a specific embodiment of the present invention, the amount of the fluorinated unsaturated compound is 1 to 1.5 parts by weight, the amount of the acrylic acid is 8 to 10 parts, the amount of 2-acrylamide-2-methylpropanesulfonic acid is 15 to 20 parts, the amount of acrylamide is 25 to 45 parts, and the amount of the polymer dispersant is 2 to 5 parts.

[0058] According to a specific embodiment of the present invention, in step 1), the solvent is water; and / or

[0059] In step 2), the pH is adjusted to 6 to 6.5; and / or the reactant solution is deoxygenated before proceeding to step 3); and / or

[0060] In step 3), the initiator is persulfate.

[0061] According to a specific embodiment of the present invention, step 2) is performed in a constant temperature water bath at 40 to 50°C; and / or

[0062] Adjust the pH with a 20 wt% sodium hydroxide aqueous solution; and / or

[0063] The deoxygenation is performed by purging the reactant solution with an inert gas (e.g., nitrogen) for at least 30 minutes; and / or

[0064] The initiator is ammonium persulfate and / or potassium persulfate.

[0065] According to a specific embodiment of the present invention, in step 3), an aqueous solution of the initiator is added to carry out the reaction to form the polymerization product and obtain the composition;

[0066] Preferably, in the aqueous solution of the initiator, the mass ratio of the initiator to water is (0.1 to 0.2):20.

[0067] According to one specific embodiment of the present invention, the reaction temperature is 45°C; and / or the reaction time is not less than 6 hours.

[0068] According to a specific embodiment of the present invention, in step 3), after the stickiness is observed to stabilize during the reaction, the reaction continues for 6 hours;

[0069] Preferably, the reaction is carried out under stirring conditions throughout.

[0070] The use of the composition according to the first aspect of the present invention or the composition prepared by the method according to the second aspect of the present invention as an acidification retarder.

[0071] Preparation of Composition

[0072] In the following examples and comparative examples, all parts of raw materials are by mass.

[0073] Example 1

[0074] 1) Place 150 parts of deionized water in a reaction vessel, and add 3 parts of PEI-7500 while stirring to obtain a polymer dispersant solution.

[0075] 2) Then add 30 parts acrylamide, 8 parts acrylic acid, 15 parts 2-acrylamide-2-methylpropanesulfonic acid and 1 part hexafluorobutyl methacrylate to the reaction vessel, adjust the pH of the system to between 6.0 and 6.5 with 20% sodium hydroxide aqueous solution, place the reactor in a 40℃ constant temperature water bath, and stir with nitrogen gas for 30 minutes to obtain the reaction solution.

[0076] 3) Dissolve 0.15 parts of potassium persulfate in 20 parts of water. After it dissolves, add it dropwise to the reaction vessel. After reacting for a period of time, the solution in the reaction vessel can be observed to start to become viscous. After the reaction is stable, continue stirring for 6 hours to obtain the composition, an acidification retarder.

[0077] Example 2

[0078] 1) Place 120 parts of deionized water in a reaction vessel, and add 2 parts of PEI-2500 while stirring to obtain a polymer dispersant solution;

[0079] 2) Then, 25 parts of acrylamide, 10 parts of acrylic acid, 15 parts of 2-acrylamido-2-methylpropanesulfonic acid and 1 part of methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide were added to the reaction vessel in sequence. The pH of the system was adjusted to between 6.0 and 6.5 with 20% sodium hydroxide aqueous solution. The reactor was placed in a 45°C constant temperature water bath for reaction. Nitrogen gas was introduced and the mixture was stirred for 30 minutes to obtain the reaction solution.

[0080] 3) Dissolve 0.1 parts of potassium persulfate in 20 parts of water. After it dissolves, add it dropwise to the reaction vessel. After reacting for a period of time, the solution in the reaction vessel can be observed to start to become viscous. After the reaction is stable, continue stirring for 6 hours to obtain the composition, an acidification retarder.

[0081] Example 3

[0082] 1) Place 150 parts of deionized water in a reaction vessel, and add 5 parts of PEG-1000 while stirring to obtain a polymer dispersant solution.

[0083] 2) Then, 30 parts of acrylamide, 8 parts of acrylic acid, 15 parts of 2-acrylamido-2-methylpropanesulfonic acid and 1.5 parts of methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide were added to the reaction vessel in sequence. The pH of the system was adjusted to between 6.0 and 6.5 with 20% sodium hydroxide aqueous solution. The reactor was placed in a constant temperature water bath at 42°C for reaction. Nitrogen gas was introduced and the mixture was stirred for 30 minutes to obtain the reaction solution.

[0084] 3) Dissolve 0.13 parts of potassium persulfate in 20 parts of water. After it dissolves, add it dropwise to the reaction vessel. After reacting for a period of time, the solution in the reaction vessel can be observed to start to become viscous. After the reaction is stable, continue stirring for 6 hours to obtain the composition, an acidification retarder.

[0085] Example 4

[0086] 1) Place 200 parts of deionized water in a reaction vessel, and add 4 parts of PEG-600 while stirring to obtain a polymer dispersant solution;

[0087] 2) Then add 40 parts acrylamide, 8 parts acrylic acid, 20 parts 2-acrylamide-2-methylpropanesulfonic acid and 1 part hexafluorobutyl acrylate to the reaction vessel in sequence. Adjust the pH of the system to between 6.0 and 6.5 with 20% sodium hydroxide aqueous solution. Place the reactor in a 42℃ constant temperature water bath for reaction. Purge with nitrogen and stir for 30 min to obtain the reaction solution.

[0088] 3) Dissolve 0.15 parts of potassium persulfate in 20 parts of water. After it dissolves, add it dropwise to the reaction vessel. After reacting for a period of time, the solution in the reaction vessel can be observed to start to become viscous. After the reaction is stable, continue stirring for 6 hours to obtain the composition, an acidification retarder.

[0089] Example 5

[0090] 1) Place 200 parts of deionized water in a reaction vessel, and add 3 parts of PEI-2500 while stirring to obtain a polymer dispersant solution;

[0091] 2) Then add 45 parts acrylamide, 10 parts acrylic acid, 20 parts 2-acrylamide-2-methylpropanesulfonic acid and 1 part hexafluoroisopropyl methacrylate to the reaction vessel in sequence. Adjust the pH of the system to between 6.0 and 6.5 with 20% sodium hydroxide aqueous solution. Place the reactor in a 50°C constant temperature water bath for reaction. Purge with nitrogen and stir for 30 min to obtain the reaction solution.

[0092] 3) Dissolve 0.2 parts of potassium persulfate in 20 parts of water. After it dissolves, add it dropwise to the reaction vessel. After reacting for a period of time, the solution in the reaction vessel can be observed to start to become viscous. After the reaction is stable, continue stirring for 6 hours to obtain the composition, an acidification retarder.

[0093] Example 6

[0094] 1) Place 150 parts of deionized water in a reaction vessel, and add 3 parts of octadecyl alcohol polyoxyethylene (40) ether while stirring to obtain a polymer dispersant solution.

[0095] 2) Then, 30 parts of acrylamide, 8 parts of acrylic acid, 15 parts of 2-acrylamido-2-methylpropanesulfonic acid and 1 part of methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide were added to the reaction vessel in sequence. The pH of the system was adjusted to between 6.0 and 6.5 with 20% sodium hydroxide aqueous solution. The reactor was placed in a 45°C constant temperature water bath for reaction. Nitrogen gas was introduced and stirred for 30 minutes to obtain the reaction solution.

[0096] 3) Dissolve 0.15 parts of potassium persulfate in 20 parts of water. After it dissolves, add it dropwise to the reaction vessel. After reacting for a period of time, the solution in the reaction vessel can be observed to start to become viscous. After the reaction is stable, continue stirring for 6 hours to obtain the composition, an acidification retarder.

[0097] Comparative Example 1

[0098] 1) Place 120 parts of deionized water in a reaction vessel. While stirring, add 25 parts of acrylamide, 10 parts of acrylic acid, 15 parts of 2-acrylamide-2-methylpropanesulfonic acid and 1 part of methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide to the reaction vessel in sequence. Adjust the pH of the system to between 6.0 and 6.5 with 20% sodium hydroxide aqueous solution. Place the reactor in a 45°C constant temperature water bath for reaction. Purge with nitrogen and stir for 30 minutes to obtain the reaction solution.

[0099] 2) Dissolve 0.1 parts of potassium persulfate in 20 parts of water. After it dissolves, add it dropwise to the reaction vessel. After reacting for a period of time, the solution in the reaction vessel can be observed to start to become viscous. After the reaction is stable, continue stirring for 6 hours. Then add 2 parts of PEI-2500 to the system to obtain the comparative composition, an acidification retarder.

[0100] Test Example 1

[0101] The compositions prepared in Examples 1 to 6 were characterized by infrared and nuclear magnetic resonance (NMR) spectra. Here, the infrared and NMR spectra of the composition prepared in Example 2 are used as examples for analysis.

[0102] Figure 1The image shows the infrared spectrum of the composition prepared in Example 2. As can be seen from the figure, the wavelengths are 3558.36, 3326.64, and 3204.01 cm⁻¹. -1 The peaks for the stretching vibrations of NH are 2978.30 and 2933.16 cm⁻¹. -1 The absorption peak is for the stretching vibrations of CH4 (methyl, methylene, etc.), at 1676.74 cm⁻¹. -1 The absorption peak is due to the stretching vibration of C=O in the amide group, at 1186.95 cm⁻¹. -1 -SO3 - The stretching vibration peak is 1096.67 cm⁻¹. -1 The absorption peak for the stretching vibration of CF is 877.74 cm⁻¹. -1 The peaks represent the ionic bond absorption peaks of quaternary ammonium salts. The absence of infrared absorption peaks for carbon-carbon double bonds in the figure indicates that the polymerized product of the composition does not contain unpolymerized monomers.

[0103] Figure 2 This is the 1H NMR spectrum of the composition prepared in Example 2. In the figure, δ = 1.00 is the chemical shift value of -CH2 in the molecular chain; δ = 1.47 is the chemical shift value of the two methyl groups on the side chain in the molecular chain; δ = 2.01 is the chemical shift value of -CH2 on the fluorinated monomer in the molecular chain; δ = 2.25 is the chemical shift value of -CH in the molecular chain; δ = 3.1 to 3.30 is the chemical shift value of -CH3 in the main chain; and δ = 7 and δ = 8.18 are the chemical shift values ​​of NH in the molecular chain.

[0104] Based on the above analysis, methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide, acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and acrylamide all participate in the polymerization reaction. The composition prepared in Example 2 is a mixture of the polymerization products of methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide, acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and acrylamide, and polyamine. Furthermore, analysis of the infrared and proton nuclear magnetic resonance spectra of the compositions prepared in Examples 1, 3 to 6 reveals that the compositions prepared in Examples 1, 3 to 6 are all mixtures of the corresponding fluorinated unsaturated compounds, the polymerization products of acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid, and acrylamide, and the corresponding polymer dispersants.

[0105] Test Example 2

[0106] i. The compositions prepared in Examples 1 to 6 and the comparative composition prepared in Comparative Example 1 were mixed with 20 wt% HCl to obtain 7 groups of acid solutions. In each group of acid solutions, the mass of the composition (or comparative composition) accounted for 3 wt% of the mass of 20 wt% HCl, and the viscosity of the acid solution was measured.

[0107] ii. Determination of the average dissolution rate of static acid solution

[0108] The carbonate rocks were processed into 7 sizes. The core column was then sealed at the bottom and around the perimeter with acid-resistant silicone sealant, leaving only a circular upper surface of the core column exposed. The initial weight was measured and recorded.

[0109] Then, weigh out equal and sufficient amounts of the 7 groups of acid solutions prepared in i, immerse all 7 treated core columns in the acid solution, carry out acid-rock reaction in a 90℃ water bath for 1 hour, take them out and weigh them, and calculate the cumulative static average acid solution dissolution rate within 1 hour.

[0110] The results of the determination of the viscosity of the acid solution and the average static acid corrosion rate are shown in Table 1.

[0111] Table 1. Viscosity of acid and average static acid corrosion rate

[0112] Example Acid viscosity / cps <![CDATA[Static acid average corrosion rate g / (cm 2 ·s)]]> Example 1 2.0543 <![CDATA[6.21×10 -4 ]]> Example 2 2.4671 <![CDATA[5.64×10 -4 ]]> Example 3 2.3156 <![CDATA[5.81×10 -4 ]]> Example 4 2.0384 <![CDATA[6.65×10 -4 ]]> Example 5 2.1568 <![CDATA[6.25×10 -4 ]]> Example 6 1.1871 <![CDATA[7.13×10 -4 ]]> Comparative Example 1 2.1362 <![CDATA[7.75×10 -4 ]]>

[0113] As can be seen from the data in Table 1, adding 3 wt% of the composition prepared in this invention to 20 wt% HCl results in an acid solution with a viscosity of only 1.1 to 2.5 cps and an average dissolution rate of only 5.64 × 10⁻⁶ for carbonate rock cores at 90°C. -4 Up to 7.13×10 -4 g / (cm 2 The invention demonstrates that the composition provided by this invention has a good retarding effect as an acidification retarder, and does not significantly increase the viscosity of the acid solution. It also exhibits good injectability, which helps reduce friction during acidification, increase the acidification distance, and achieve deep acidification. Furthermore, compared to Example 2, Comparative Example 2 simply incorporates a polymer dispersant at the end of the preparation process. Although the viscosity of the comparative composition is slightly lower, the average dissolution rate of the acid solution containing this comparative composition is higher, reaching 7.75 × 10⁻⁶. -4 g / (cm 2 The average dissolution rate increased by 37% compared to Example 2, indicating that the retardation effect of the comparative composition provided in Comparative Example 1 was significantly worse than that in Example 2, proving that the composition prepared according to the method provided by the present invention has better retardation performance.

[0114] Plotting the reaction rate-time curves of the iii acid-rock reaction

[0115] Carbonate rocks are processed to specifications. The core column was then sealed at the bottom and around the perimeter with acid-resistant silicone sealant, leaving only a circular upper surface of the core column exposed. The initial weight was measured and recorded.

[0116] Then, 250 mL of the acid solution prepared using the composition prepared in Example 2 (i) was weighed, and the entire treated core column was immersed in the acid solution. The acid-rock reaction was carried out in a 90°C water bath for 100 min. The core was removed and weighed every 5 min to calculate the core dissolution rate. The core dissolution rate at different time points was then plotted as a core dissolution rate-time curve, serving as the experimental group. The results are shown below. Figure 3 ;

[0117] Following the same method, treated core columns of the same specifications were immersed in 250 mL of 20 wt% HCl for testing, serving as a control group. The results were also observed. Figure 3 .

[0118] Depend on Figure 3 The two curves show that, within the reaction time of 0 to 100 minutes, the acid-rock reaction rate of the control group was significantly higher than that of the experimental group at any time point. Comparing the acid formulations of the control and experimental groups reveals that the experimental group's acid solution contained 3 wt% of the composition prepared in Example 2. The significant decrease in the acid-rock reaction rate of the experimental group demonstrates that the composition prepared in Example 2 has the effect of retarding the reaction rate between hydrochloric acid and the core. Furthermore, the maximum change in the acid-rock reaction rate of the control group within 0 to 100 minutes was not significantly different from that of the experimental group within the same timeframe, indicating that the composition prepared in Example 2, while retarding the acid-rock reaction rate, did not have any other adverse effects on the acidification process. Figure 3 It can be seen that the composition prepared in Example 2 is an acidification retarder with excellent slowing effect.

[0119] While the present invention has been described with reference to specific embodiments, those skilled in the art will understand that various changes can be made without departing from the true spirit and scope of the invention. Furthermore, numerous modifications can be made to the subject, spirit, and scope of the invention to suit specific situations, materials, material compositions, and methods. All such modifications are included within the scope of the claims of the present invention.

Claims

1. A composition comprising a fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, a polymeric product of acrylamide, and a polymeric dispersant; The amount of the fluorinated unsaturated compound is 0.5 to 2 parts by weight, the amount of the acrylic acid is 5 to 10 parts, the amount of 2-acrylamide-2-methylpropanesulfonic acid is 10 to 20 parts, the amount of the acrylamide is 20 to 50 parts, and the amount of the polymer dispersant is 2 to 5 parts. The fluorinated unsaturated compound includes at least one of methacrylamide propyl dimethyl perfluorobutyl ethyl ammonium iodide, hexafluorobutyl methacrylate, hexafluorobutyl acrylate, and hexafluoroisopropyl methacrylate. The polymeric dispersant includes at least one of polyamine, polyethylene glycol, and octadecyl alcohol polyoxyethylene ether; The composition was prepared according to the following steps: 1) The polymer dispersant and solvent are mixed to obtain a polymer dispersant solution; 2) Mix the fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, and the polymer dispersant solution, and adjust the pH to obtain a reactant solution; 3) The reactant solution is reacted under the action of an initiator to form the polymerization product, thereby obtaining the composition.

2. The composition according to claim 1, characterized in that, The polyamine has a molecular weight of 500 to 25,000; and / or The molecular weight of the polyethylene glycol is between 400 and 2000.

3. The composition according to claim 1, characterized in that, The total mass of the fluorinated unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide is 100%, and the mass of the initiator is 0.2 to 0.3 wt%.

4. The composition according to claim 1, characterized in that, In step 1), the solvent is water; and / or In step 2), adjust the pH to 6 to 6.5; and / or In step 3), the initiator is persulfate.

5. The composition according to claim 1, characterized in that, The reaction temperature is 40 to 50°C; and / or the duration is not less than 6 hours.

6. The use of the composition according to any one of claims 1 to 5 as an acidification retarder.

Images