Composition as well as preparation method and application thereof

Abstract

The invention provides a composition as well as a preparation method and application thereof. The composition comprises a fluorine-containing unsaturated compound, a polymerization product of acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide, and a high-molecular polymer dispersant, and can be used as an acidification retarder.

Description

Technical Field

[0001] The invention belongs to the technical field of oil field acidification and production increase, and in particular relates to a composition, a preparation method and application thereof. Background Art

[0002] Matrix acidizing, also known as conventional acidizing or deblocking acidizing, refers to the acidizing technology of injecting acid into the formation under the condition that the bottom hole construction pressure is less than the fracture pressure of the reservoir rock, removing the damage near the wellbore and restoring the reservoir production capacity. Since matrix acidizing is a technology that does not pressurize the formation, the acid mainly flows in the rock pores and natural cracks, and reacts in the holes with good seepage capacity. When the blockage and part of the rock react with the acid quickly, the rock wall will be quickly dissolved in the direction of strong reactivity, forming acid-etched holes. These holes become the main channels for improving the seepage capacity of the reservoir. The acid systems currently used in matrix acidizing include conventional acid systems, thickened acid systems, gel acid systems and diverting acid systems. The specific situations and existing problems are as follows:

[0003] (1) Conventional acid system: Conventional acid fracturing technology refers to the process technology of acid fracturing the formation using only ordinary hydrochloric acid. During the construction, no sand is added, no pre-fluid is used, and no special backflow technology is used. Ordinary hydrochloric acid is both a liquid that presses open the formation cracks and a liquid that reacts with the formation. Due to the poor control of acid loss, the acid-rock reaction rate is fast, and the acid etching distance is short, generally between 15 and 30m. It is mainly suitable for severely damaged high-permeability reservoirs. For low-pressure oil wells and low-permeability formations, it is difficult to return the residual acid after acidizing, which is easy to cause secondary pollution and affect the acidizing effect. In addition, the acid-rock reaction rate of conventional acidizing is too fast, and the acid is mainly consumed within 0.5m of the near-well area, which cannot remove the deep blockage of the oil well.

[0004] (2) Thickened acid liquid system: Thickened acid liquid refers to an acid liquid system in which a non-crosslinked acid thickener is added to the acid liquid to increase the viscosity of the acid liquid. Thickened acid has a high viscosity, can control filtration, increase the width and length of the cracks, thereby delaying the acid-rock reaction rate and increasing the penetration distance of the active acid; at the same time, it can reduce friction, increase the construction displacement, and better achieve deep acidization transformation. The optimal viscosity of thickened acid entering the ground is 30 to 40 mPa·s, and the residual acid viscosity should generally be between 5 and 10 mPa·s, so as to facilitate backflow and carry solid particles in the cracks, reducing the secondary damage of the acid liquid to the formation. In field applications, thickened acid is required to have good thermal stability, a small fresh acid viscosity reduction rate, complete gel breaking, a low residual acid viscosity, and easy backflow. The disadvantage of this technology is that the residual acid is not completely backflowed. According to relevant analysis, after the acidization treatment is completed, only 30% to 45% of the injected polymer can be backflowed, and a considerable amount of polymer remains in the formation. Although a series of measures have been tried to remove the residual polymer, the results are minimal.

[0005] (3) Gelled acid system: Gelled acid is an acid system prepared by adding an acid gelling agent and additives to ordinary hydrochloric acid. Gelled acid has the advantages of slowing down, reducing filtration and easy drainage. After the acid is thickened, the convection between the acid and the rock is restricted, and the transfer of hydrogen ions is limited to diffusion, thereby effectively slowing down the reaction rate. At the same time, the width of the crack is proportional to the viscosity of the fluid. The width of the crack opened by the thickened acid is large, thereby reducing the acid-rock surface ratio. The acid consumption rate is reduced and the effective action distance of the active acid is increased. Gel acid is used to adjust the viscosity of the acid to reduce H + mass transfer rate and reaction rate, but the increase in viscosity causes increased friction and leads to reduced pumping efficiency.

[0006] (4) Redirecting acid system: The redirecting acid uniform distribution acid fracturing technology mainly uses hydrochloric acid viscoelastic surfactant as acid. After being squeezed into the formation, the active agent 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 redirecting the rock layer. This technology is not only an improvement on the acid fracturing technology, but also can improve the permeability of low permeability reservoirs and improve the transformation effect of carbonate reservoirs. However, the high-temperature redirecting acid system usually uses erucic acid amide propyl betaine, with an addition of more than 6%. During the acidizing process of gas wells, the residual acid viscosity is often high, and it is difficult to return. A large amount of acidizing mutual solvent needs to be added.

[0007] In summary, the existing acid system has the problems of high viscosity, high construction friction and insufficient formation damage. It is necessary to further reduce the viscosity of the acid system and explore new types of long-distance reaction acid to form new technologies and systems that can increase the transformation volume and are economical and effective. Summary of the invention

[0008] The first aspect of the present invention provides a composition comprising a fluorine-containing unsaturated compound, acrylic acid, a polymerization product of 2-acrylamide-2-methylpropanesulfonic acid and acrylamide, and a high molecular polymer dispersant.

[0009] According to a specific embodiment of the present invention, the amount of the fluorine-containing unsaturated compound is 0.5 to 2 parts, the amount of the acrylic acid is 5 to 10 parts, the amount of the 2-acrylamide-2-methylpropane sulfonic acid is 10 to 20 parts, the amount of the acrylamide is 20 to 50 parts, and the amount of the high molecular polymer dispersant is 2 to 5 parts.

[0010] According to a specific embodiment of the present invention, the fluorine-containing unsaturated compound includes at least one of methacrylamidopropyldimethylperfluorobutylethylammonium iodide, hexafluorobutyl methacrylate, hexafluorobutyl acrylate and hexafluoroisopropyl methacrylate.

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

[0012] According to a specific embodiment of the present invention, the molecular weight of the polyamine is 500 to 25000; and / or

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

[0014] The second aspect of the present invention provides a method for preparing the composition according to the first aspect of the present invention, comprising the following steps:

[0015] 1) mixing the polymer dispersant and a solvent to obtain a polymer dispersant solution;

[0016] 2) mixing the fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and the high molecular weight polymer dispersant, adjusting the pH, and obtaining a reactant solution;

[0017] 3) allowing the reactant solution to react under the action of an initiator to form the polymer product to obtain the composition.

[0018] According to a specific embodiment of the present invention, the amount of the polymer dispersant is 2 to 5 parts, the amount of the fluorine-containing unsaturated compound is 0.5 to 2 parts, the amount of the acrylic acid is 5 to 10 parts, the amount of the 2-acrylamide-2-methylpropane sulfonic acid is 10 to 20 parts, and the amount of the 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 fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide; and / or

[0021] The total weight of the fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide is calculated as 100%, and the weight of 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), the pH is adjusted to 6 to 6.5; and / or

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

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

[0026] 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] Beneficial effects of the present invention:

[0028] In view of the problems of high viscosity, high construction friction and insufficient formation damage in the existing acid system, the present invention provides a composition, a preparation method and application thereof. The composition includes a fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid and a polymerization product of acrylamide and a high molecular polymer dispersant, and is an acidification retarder. In the composition, acrylamide is used to provide a repeatable polymerization monomer, which is polymerized to form a water-soluble polymerization product. The 2-acrylamide-2-methylpropane sulfonic acid added during the synthesis process introduces a sulfonic acid group, so that the composition can be used as an acidification retarder and can be adsorbed on the rock surface during the acidification process; the high molecular polymer dispersant is used to increase the solubility of the fluorine-containing unsaturated compound in the polymerization system, thereby improving the polymerization efficiency, which is beneficial for the composition to increase the number of fluorocarbon chains arranged in a directional manner on the rock surface during the acidification process, and is more convenient to form a hydrophobic film, effectively reducing H + Diffusion, to achieve the effect of deep acidification; and the introduction of fluorine-containing unsaturated compounds in the preparation process of the composition, after acid fracturing, the reverse flow can be used as a gas wetting reversal agent on the surface of dense sandstone, which can effectively avoid the water lock phenomenon in the development of dense sandstone gas reservoirs. According to experimental measurements, adding 3wt% of the composition to 20wt% HCl, the viscosity and retarding effect of the obtained acid solution are as follows: 1) The viscosity is only 1.1 to 2.5cps, and the lower viscosity is conducive to reducing construction friction and enhancing the injectability of the acid solution; 2) The average dissolution rate of carbonate core columns in acid solution at 90°C is 5.64×10 -4 to 7.13×10 -4 g / (cm 2 ·s), compared with 20wt% HCl, the acid-rock reaction rate of the acid solution to which the composition is added is significantly reduced, the retardation effect is good, and the requirement for deep acidification is met. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0030] Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the composition prepared in Example 2;

[0031] Figure 3 This is the reaction rate-time curve of the acid-rock reaction of the core column at 90°C. DETAILED DESCRIPTION

[0032] The present invention will be further described below in conjunction with examples, but the examples of the present invention are only exemplary descriptions, and the implementation methods do not constitute limitations of the present invention under any circumstances.

[0033] The first aspect of the present invention provides a composition comprising a fluorine-containing unsaturated compound, acrylic acid, a polymerization product of 2-acrylamide-2-methylpropanesulfonic acid and acrylamide, and a high molecular polymer dispersant.

[0034] According to a specific embodiment of the present invention, the amount of the fluorine-containing unsaturated compound is 0.5 to 2 parts, the amount of the acrylic acid is 5 to 10 parts, the amount of the 2-acrylamide-2-methylpropane sulfonic acid is 10 to 20 parts, the amount of the acrylamide is 20 to 50 parts and the amount of the high molecular polymer dispersant is 2 to 5 parts.

[0035] According to a specific embodiment of the present invention, the amount of the fluorine-containing unsaturated compound is 1 to 1.5 parts, the amount of the acrylic acid is 8 to 10 parts, the amount of the 2-acrylamide-2-methylpropane sulfonic acid is 15 to 20 parts, the amount of the acrylamide is 25 to 45 parts and the amount of the high molecular polymer dispersant is 2 to 5 parts.

[0036] According to a specific embodiment of the present invention, the fluorine-containing unsaturated compound includes at least one of methacrylamidopropyldimethylperfluorobutylethylammonium iodide, hexafluorobutyl methacrylate, hexafluorobutyl acrylate and hexafluoroisopropyl methacrylate.

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

[0038] According to a specific embodiment of the present invention, the molecular weight of the polyamine is 500 to 25000; and / or

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

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

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

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

[0043] According to a specific embodiment of the present invention, the high molecular polymer dispersant includes polyamine and / or stearyl alcohol polyoxyethylene ether.

[0044] According to a specific embodiment of the present invention, the molecular weight of the polyamine is 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 stearyl alcohol polyoxyethylene ether is stearyl alcohol polyoxyethylene (40) ether.

[0048] The second aspect of the present invention provides a method for preparing the composition according to the first aspect of the present invention, comprising the following steps:

[0049] 1) mixing the polymer dispersant and a solvent to obtain a polymer dispersant solution;

[0050] 2) mixing the fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and the high molecular weight polymer dispersant, adjusting the pH, and obtaining a reactant solution;

[0051] 3) allowing the reactant solution to react under the action of an initiator to form the polymer product to obtain the composition.

[0052] According to a specific embodiment of the present invention, the amount of the polymer dispersant is 2 to 5 parts, the amount of the fluorine-containing unsaturated compound is 0.5 to 2 parts, the amount of the acrylic acid is 5 to 10 parts, the amount of the 2-acrylamide-2-methylpropane sulfonic acid is 10 to 20 parts, and the amount of the 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 fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide; and / or

[0055] The total weight of the fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide is 100%, and the weight of the initiator accounts for 0.2 to 0.3 wt %;

[0056] Preferably, taking the mass of the high molecular weight polymer dispersant solution as 100%, the mass of the solvent accounts for 96 to 99 wt %.

[0057] According to a specific embodiment of the present invention, the amount of the fluorine-containing unsaturated compound is 1 to 1.5 parts, the amount of the acrylic acid is 8 to 10 parts, the amount of the 2-acrylamide-2-methylpropane sulfonic acid is 15 to 20 parts, the amount of the acrylamide is 25 to 45 parts, and the amount of the high molecular 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 performing step 3); and / or

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

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

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

[0063] Passing an inert gas (such as nitrogen) into the reactant solution for not less than 30 minutes to perform the deoxygenation; 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 polymer product to 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 a 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), during the reaction, after stickiness is observed until the reaction is stable, the reaction is continued for 6 hours;

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

[0070] 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] The parts of raw materials in the following examples and comparative examples are all parts by mass.

[0073] Example 1

[0074] 1) 150 parts of deionized water were placed in a reaction kettle, and 3 parts of PEI-7500 were added during stirring to obtain a polymer dispersant solution;

[0075] 2) Then, 30 parts of acrylamide, 8 parts of acrylic acid, 15 parts of 2-acrylamide-2-methylpropanesulfonic acid and 1 part of hexafluorobutyl methacrylate were added to the reaction kettle, and the pH of the system was adjusted to between 6.0 and 6.5 with a 20% sodium hydroxide aqueous solution. The reactor was placed in a constant temperature water bath at 40° C., and nitrogen was introduced and stirred for 30 minutes to obtain a reactant solution;

[0076] 3) Dissolve 0.15 parts of potassium persulfate in 20 parts of water, and add it dropwise into the reactor after it is dissolved. After a period of reaction, it can be observed that the solution in the reaction container begins to become sticky. After the reaction is stable, continue stirring for 6 hours to obtain a composition, which is an acidification retarder.

[0077] Example 2

[0078] 1) 120 parts of deionized water were placed in a reaction kettle, and 2 parts of PEI-2500 were added during stirring to obtain a polymer dispersant solution;

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

[0080] 3) Dissolve 0.1 parts of potassium persulfate in 20 parts of water, and add it dropwise into the reactor after it is dissolved. After a period of reaction, it can be observed that the solution in the reaction container begins to become sticky. After the reaction is stable, continue stirring for 6 hours to obtain a composition, which is an acidification retarder.

[0081] Example 3

[0082] 1) 150 parts of deionized water were placed in a reaction kettle, and 5 parts of PEG-1000 were added during stirring to obtain a high molecular weight polymer dispersant solution;

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

[0084] 3) Dissolve 0.13 parts of potassium persulfate in 20 parts of water, and add it dropwise into the reactor after it is dissolved. After a period of reaction, it can be observed that the solution in the reaction container begins to become sticky. After the reaction is stable, continue stirring for 6 hours to obtain a composition, which is an acidification retarder.

[0085] Example 4

[0086] 1) 200 parts of deionized water were placed in a reaction kettle, and 4 parts of PEG-600 were added during stirring to obtain a high molecular weight polymer dispersant solution;

[0087] 2) Then, 40 parts of acrylamide, 8 parts of acrylic acid, 20 parts of 2-acrylamide-2-methylpropanesulfonic acid and 1 part of hexafluorobutyl acrylate were added to the reaction kettle in sequence, and the pH of the system was adjusted to between 6.0 and 6.5 with a 20% aqueous sodium hydroxide solution. The reactor was placed in a 42° C. constant temperature water bath for reaction, and nitrogen was introduced and stirred for 30 minutes to obtain a reactant solution;

[0088] 3) Dissolve 0.15 parts of potassium persulfate in 20 parts of water, and add it dropwise into the reactor after it is dissolved. After a period of reaction, it can be observed that the solution in the reaction container begins to become sticky. After the reaction is stable, continue stirring for 6 hours to obtain a composition, which is an acidification retarder.

[0089] Example 5

[0090] 1) 200 parts of deionized water were placed in a reaction kettle, and 3 parts of PEI-2500 were added during stirring to obtain a polymer dispersant solution;

[0091] 2) Then, 45 parts of acrylamide, 10 parts of acrylic acid, 20 parts of 2-acrylamide-2-methylpropanesulfonic acid and 1 part of hexafluoroisopropyl methacrylate were added to the reaction kettle in sequence, and the pH of the system was adjusted to between 6.0 and 6.5 with a 20% aqueous sodium hydroxide solution. The reactor was placed in a 50° C. constant temperature water bath for reaction, and nitrogen was introduced and stirred for 30 minutes to obtain a reactant solution;

[0092] 3) Dissolve 0.2 parts of potassium persulfate in 20 parts of water, and add it dropwise into the reactor after it is dissolved. After a period of reaction, it can be observed that the solution in the reaction container begins to become sticky. After the reaction is stable, continue stirring for 6 hours to obtain a composition, which is an acidification retarder.

[0093] Example 6

[0094] 1) 150 parts of deionized water are placed in a reaction kettle, and 3 parts of octadecyl alcohol polyoxyethylene (40) ether are added during stirring to obtain a high molecular weight polymer dispersant solution;

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

[0096] 3) Dissolve 0.15 parts of potassium persulfate in 20 parts of water, and add it dropwise into the reactor after it is dissolved. After a period of reaction, it can be observed that the solution in the reaction container begins to become sticky. After the reaction is stable, continue stirring for 6 hours to obtain a composition, which is an acidification retarder.

[0097] Comparative Example 1

[0098] 1) 120 parts of deionized water are placed in a reaction kettle, and 25 parts of acrylamide, 10 parts of acrylic acid, 15 parts of 2-acrylamide-2-methylpropanesulfonic acid and 1 part of methacrylamidepropyl dimethyl perfluorobutyl ethyl ammonium iodide are added to the reaction kettle in sequence during stirring, and the pH of the system is adjusted to between 6.0 and 6.5 with a 20% sodium hydroxide aqueous solution, and the reactor is placed in a 45° C. constant temperature water bath for reaction, and nitrogen is introduced and stirred for 30 minutes to obtain a reactant solution;

[0099] 2) 0.1 parts of potassium persulfate was dissolved in 20 parts of water, and after it was dissolved, it was added dropwise into the reactor. After a period of reaction, it was observed that the solution in the reaction container began to become sticky. After the reaction was stable, stirring was continued for 6 hours, and then 2 parts of PEI-2500 were added to the system to obtain a comparative composition, an acidification retarder.

[0100] Test Example 1

[0101] The compositions prepared in Examples 1 to 6 were characterized by measuring infrared spectra and nuclear magnetic resonance proton spectra. Here, the infrared spectrum and nuclear magnetic resonance proton spectrum of the composition prepared in Example 2 were taken as an example for analysis.

[0102] Figure 1This is the infrared spectrum of the composition prepared in Example 2. As can be seen from the figure, 3558.36, 3326.64, 3204.01 cm -1 The stretching vibration peaks of NH are 2978.30 and 2933.16 cm -1 It is the stretching vibration absorption peak of CH such as methyl and methylene, 1676.74cm -1 is the stretching vibration absorption peak of C=O in the amide group, 1186.95 cm -1 For-SO 3 - Stretching vibration peak, 1096.67cm -1 is the stretching vibration absorption peak of CF, 877.74 cm -1 It is the ionic bond absorption peak of the quaternary ammonium salt. There is no infrared absorption peak of the carbon-carbon double bond in the figure, which indicates that there is no unpolymerized monomer in the polymerization product of the composition.

[0103] Figure 2 is the H NMR spectrum of the composition prepared in Example 2. In the figure, δ=1.00 is the -CH 2 δ = 1.47 is the chemical shift value of the two methyl groups on the side chain of the molecular chain; δ = 2.01 is the chemical shift value of the -CH 2 The chemical shift value of 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 -CH in the main chain 3 ; δ=7 and δ=8.18 are the chemical shift values ​​of NH in the molecular chain.

[0104] Based on the above analysis, it can be seen that methacrylamidopropyl dimethyl perfluorobutyl ethyl ammonium iodide, acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid and acrylamide all participate in the polymerization reaction, and the composition prepared in Example 2 is a mixture of a polymerization product of methacrylamidopropyl dimethyl perfluorobutyl ethyl ammonium iodide, acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid and acrylamide and a polyamine; and, by analyzing the infrared spectrum and hydrogen nuclear magnetic resonance spectrum of the compositions prepared in Examples 1, 3 to 6, it is known that the compositions prepared in Examples 1, 3 to 6 are all mixtures of a polymerization product of a corresponding fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid and acrylamide and a corresponding high molecular polymer dispersant.

[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 respectively 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 solutions was measured;

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

[0108] The carbonate rock is made into 7 specifications The core column is then sealed with acid-resistant silicon copper glue at the bottom and around the core column, leaving only a circular upper surface of the core column exposed, and the initial weight is weighed and recorded;

[0109] Then, equal and sufficient amounts of the 7 groups of acid solutions prepared in step 1 are weighed, and the 7 treated core columns are immersed in the acid solutions respectively, and the acid-rock reaction is carried out in a 90°C water bath for 1 hour. The core columns are taken out and weighed, and the cumulative static average acid solution dissolution rate within 1 hour is calculated;

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

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

[0112] Example Acid viscosity / cps <![CDATA[Static average acid 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] From the data in Table 1, it can be seen that when 3 wt % of the composition prepared in the present invention is added to 20 wt % HCl, the viscosity of the obtained acid solution is only 1.1 to 2.5 cps, and the average dissolution rate of the carbonate core column in the acid solution at 90 ° C is only 5.64×10 -4 to 7.13×10 -4 g / (cm 2 ·s), proving that the composition provided by the present invention has a good retarding effect as an acidification retarder, and does not significantly increase the viscosity of the acid solution, has good injectability, is conducive to reducing the friction resistance of acidification construction, increasing the acidification distance, and achieving deep acidification. Further, compared with Example 2, in the preparation process of Comparative Example 2, the high molecular weight polymer dispersant is simply added at the end. Although the viscosity of the comparative composition obtained is slightly reduced, the average dissolution rate of the acid solution added with the comparative composition is higher, reaching 7.75×10 -4 g / (cm 2 ·s), the average dissolution rate increased by 37% compared with that of Example 2, indicating that compared with Example 2, the retarding effect of the comparative composition provided in Comparative Example 1 is significantly worse, proving that the composition prepared according to the method provided by the present invention has better retarding performance.

[0114] ⅲ Reaction rate-time curve drawing of acid rock reaction

[0115] Carbonate rocks are made into The core column is then sealed with acid-resistant silicon copper glue at the bottom and around the core column, leaving only a circular upper surface of the core column exposed, and the initial weight is weighed and recorded;

[0116] Then weigh 250 mL of the acid solution prepared by the composition prepared in Example 2 in ⅰ, immerse all the treated core columns in the acid solution, and carry out acid-rock reaction in a 90°C water bath for 100 min. Take out and weigh after every 5 min of reaction, calculate the core dissolution rate, and then plot the core dissolution rate at different time points into a core dissolution rate-time curve as the experimental group. The results are shown in Figure 3 ;

[0117] In the same way, the treated core columns of the same specifications were immersed in 250mL 20wt% HCl for the experiment as a control group. The results are also shown in Figure 3 .

[0118] Depend on Figure 3 It can be seen from the two curves that within the reaction time of 0 to 100 minutes, the acid-rock reaction rate of the control group at any time point is much higher than that of the experimental group. By comparing the acid solution formulas of the control group and the experimental group, it can be seen that 3 wt% of the composition prepared in Example 2 was added to the acid solution of the experimental group. The obvious decrease in the acid-rock reaction rate of the experimental group proves that the composition prepared in Example 2 has the effect of delaying the reaction rate of hydrochloric acid and core; in addition, the maximum change in the acid-rock reaction rate of the control group within 0 to 100 minutes is not much different from the maximum change in the acid-rock reaction rate of the experimental group within 0 to 100 minutes, indicating that the composition prepared in Example 2 has no other adverse effects on the acidification process while delaying the acid-rock reaction rate. Analysis Figure 3 It can be seen that the composition prepared in Example 2 is an acidification retarder with excellent retarding effect.

[0119] Although the present invention has been described with reference to specific embodiments, it will be appreciated by those skilled in the art that various changes may be made without departing from the true spirit and scope of the present invention. In addition, the subject matter, spirit and scope of the present invention may be varied to accommodate specific situations, materials, material combinations and methods. All of these changes are included within the scope of the claims of the present invention.

Claims

1. A composition comprising a fluorine-containing unsaturated compound, acrylic acid, a polymerization product of 2-acrylamide-2-methylpropanesulfonic acid and acrylamide, and a high molecular polymer dispersant.

2. The composition according to claim 1, characterized in that In parts by mass, the amount of the fluorine-containing unsaturated compound is 0.5 to 2 parts, the amount of the acrylic acid is 5 to 10 parts, the amount of the 2-acrylamide-2-methylpropane sulfonic acid is 10 to 20 parts, the amount of the acrylamide is 20 to 50 parts, and the amount of the high molecular polymer dispersant is 2 to 5 parts.

3. The composition according to claim 1 or 2, characterized in that The fluorine-containing unsaturated compound includes at least one of methacrylamidopropyldimethylperfluorobutylethylammonium iodide, hexafluorobutyl methacrylate, hexafluorobutyl acrylate and hexafluoroisopropyl methacrylate.

4. The composition according to any one of claims 1 to 3, characterized in that The high molecular polymer dispersant includes at least one of polyamine, polyethylene glycol and octadecyl alcohol polyoxyethylene ether.

5. The composition according to claim 4, characterized in that The molecular weight of the polyamine is 500 to 25000; and / or The molecular weight of the polyethylene glycol is 400 to 2000.

6. A method for preparing a composition as claimed in any one of claims 1 to 5, comprising the steps of: 1) mixing the polymer dispersant and a solvent to obtain a polymer dispersant solution; 2) mixing the fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid, acrylamide and the high molecular weight polymer dispersant solution, adjusting the pH, and obtaining a reactant solution; 3) allowing the reactant solution to react under the action of an initiator to form the polymer product to obtain the composition.

7. The method according to claim 6, characterized in that In parts by mass, the polymer dispersant is used in an amount of 2 to 5 parts, the fluorine-containing unsaturated compound is used in an amount of 0.5 to 2 parts, the acrylic acid is used in an amount of 5 to 10 parts, the 2-acrylamide-2-methylpropanesulfonic acid is used in an amount of 10 to 20 parts, and the acrylamide is used in an amount of 20 to 50 parts; and / or The total weight of the fluorine-containing unsaturated compound, acrylic acid, 2-acrylamide-2-methylpropanesulfonic acid and acrylamide is calculated as 100%, and the weight of the initiator accounts for 0.2 to 0.3 wt %.

8. The method according to claim 6 or 7, characterized in that: In step 1), the solvent is water; and / or In step 2), the pH is adjusted to 6 to 6.5; and / or In step 3), the initiator is persulfate.

9. The method according to any one of claims 6 to 8, characterized in that The reaction temperature is 40 to 50° C.; and / or the reaction time is not less than 6 hours.

10. Use of the composition according to any one of claims 1 to 5 or the composition prepared by the method according to any one of claims 6 to 9 as an acidification retarder.

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