Seawater fast-dissolving type temperature-resistant polyacrylamide as well as preparation process and device thereof
By adding specific functional monomers and high-temperature stabilizers to the preparation process of polyacrylamide, the problem of insufficient temperature resistance and dissolution performance in offshore oil production is solved, and the efficient displacement effect is achieved in high-temperature and high-salt environments.
Patent Information
- Application Number
- CN202411850475.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-16
- Publication Date
- 2025-03-28
AI Technical Summary
During offshore oil production, polyacrylamide has insufficient temperature resistance and dissolution properties in high temperature and high salt environments, resulting in poor displacement effect.
Through the preparation process, 2-acrylamide-2-methylpropanesulfonic acid and 1-vinyl-2-pyrrolidone are added for polymerization, and high-temperature stabilizers such as thiourea, amino acids, etc. are added during the polymerization process to form instant-soluble temperature-resistant polyacrylamide in seawater.
The temperature resistance and dissolution properties of polyacrylamide in seawater are improved, ensuring that it maintains a high viscosity and displacement effect under high temperature environments.
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Figure CN119708339A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of polyacrylamide for oil recovery, and in particular to a seawater-soluble, heat-resistant polyacrylamide and a preparation process and device thereof. Background Art
[0002] In the later stage of the development of offshore water-driven oil fields, in order to further improve the recovery rate of crude oil, tertiary oil recovery chemical flooding is required. The usual practice is to inject polyacrylamide solution into the formation to improve the mobility ratio and expand the swept volume. Polyacrylamide is a linear water-soluble polymer chemical agent. In water, it is easy to form hydrogen bonds with water. After hydration, it has strong hydrodynamics and high viscosity. Ordinary partially hydrolyzed polyacrylamide solution has poor temperature resistance. Generally, polyacrylamide molecules will break when the temperature exceeds 80°C, resulting in a decrease in viscosity and a poor displacement effect. In offshore oil production, fresh water resources are scarce. If seawater is used to prepare polyacrylamide solution, its increased mineralization will cause a decrease in solubility and viscosity. In addition, the area of offshore drilling platforms is limited, and the ground equipment needs to be simplified and the floor space reduced. For this reason, polyacrylamide products are required to be both temperature-resistant and salt-resistant, and to dissolve quickly. Summary of the invention
[0003] In order to improve the temperature resistance and solubility of polyacrylamide in seawater, the present application provides a seawater-soluble heat-resistant polyacrylamide and a preparation process and device thereof.
[0004] The present application provides a preparation process of seawater instant heat-resistant polyacrylamide, which adopts the following technical scheme: a preparation process of seawater instant heat-resistant polyacrylamide, comprising the following steps: adding acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, 1-vinyl-2-pyrrolidone and deionized water into a reactor, mixing and fully dissolving, and then adjusting the pH value to 10.0-11.0; cooling the solution in the reactor to -2-0°C, and introducing nitrogen for deoxygenation for 15 minutes; then adding an ion shielding agent, a chain transfer agent and an initiator, stirring and conducting a closed reaction to obtain a viscous mixed solution; adding granular sodium hydroxide and sodium bisulfite to the mixed solution and then hydrolyzing it, the hydrolysis temperature is 90°C, and the hydrolysis time is 6 hours to prepare a colloid; taking out the colloid, adding a high-temperature stabilizer, kneading the mud evenly, drying, crushing, and sieving to form a seawater instant heat-resistant polyacrylamide; the high-temperature stabilizer is one of thiourea, amino acid, oxalate, citrate, and salicylate.
[0005] By adopting the above technical scheme, acrylamide, 2-acrylamide-2-methylpropane sulfonic acid and 1-vinyl-2-pyrrolidone are polymerized together. The introduction of 2-acrylamide-2-methylpropane sulfonic acid can utilize its functional monomer of strong polar anion to make polyacrylamide have better complexation and hydrolysis stability, thereby improving the salt resistance of the synthetic polyacrylamide, which is more conducive to use in seawater. At the same time, the ring structure in the molecule of 2-pyrrolidone may increase the viscoelasticity of the molecular chain of the polymer and improve the viscosity. At the same time, adding a high-temperature stabilizer to the colloid formed after the polymerization can effectively inhibit the shrinkage and dehydration of seawater with high calcium and magnesium ions in a high temperature environment, improve the stability, and enable the polyacrylamide to maintain a high viscosity for a long time at a high temperature.
[0006] Preferably, the weight ratio of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, 1-vinyl-2-pyrrolidone and deionized water is 50:5.5-6.5:0.8-1.2:150-300.
[0007] Preferably, the weight ratio of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, 1-vinyl-2-pyrrolidone and deionized water is 50:6:1:200.
[0008] Preferably, the initiator comprises an oxidant, a reducing agent and a bifunctional initiator, and the weight ratio of the oxidant, the reducing agent and the bifunctional initiator is 1:0.5:12-20.
[0009] Preferably, the oxidizing agent is tert-butyl hydroperoxide and the reducing agent is formic acid.
[0010] Preferably, the preparation steps of the bifunctional initiator include adding a 30% hydrogen peroxide solution and adding concentrated sulfuric acid dropwise, and then reducing the temperature to below 5°C; adding 2,5-dimethyl-2,5-hexanediol to the above-mentioned mixed system, reacting at below 5°C for about 40 minutes, until a small amount of white solid precipitates in the late stage of the reaction, and then raising the temperature to 25°C to react for about 60 minutes. During the heating process, the white solid precipitates increase, and the bifunctional initiator is obtained by filtering.
[0011] Preferably, the chain transfer agent is one of sodium formate, sodium hypophosphite, isopropyl alcohol and thioglycolic acid.
[0012] The present application also provides a seawater-soluble heat-resistant polyacrylamide, which adopts the following technical solution: A seawater-soluble heat-resistant polyacrylamide is prepared by adopting the preparation process of the seawater-soluble heat-resistant polyacrylamide.
[0013] The present application also provides a preparation device for seawater instant heat-resistant polyacrylamide, which adopts the following technical scheme: a preparation device for seawater instant heat-resistant polyacrylamide, characterized in that a rotating stirring shaft is arranged in the reactor, and two stirring blades are arranged on the stirring shaft. The stirring blade includes two movable rods and a winding blade arranged between the two movable rods, one end of the two movable rods is rotatably connected to the stirring shaft, and a winding shaft is arranged inside the movable rod, and both sides of the winding blade are rolled on the winding shaft.
[0014] Preferably, a worm gear is fixedly provided at one end of the movable rod, and the worm gear is rotatably connected to the stirring shaft. The winding shaft is rotatably connected to the inside of the movable rod and is connected to the driven bevel gear at one end of the movable rod. An active bevel gear is fixedly provided inside the stirring shaft, and the active bevel gear is coaxially arranged with the worm gear. The active bevel gear is meshed with the driven bevel gear. The worm gears on the two movable rods are respectively connected to a worm, and the two worms are coaxially and fixedly connected, and the worm is rotatably connected inside the stirring shaft.
[0015] In summary, the present application includes at least one of the following beneficial technical effects: 1. The redox initiation system formed by the bifunctional initiator, tert-butyl hydroperoxide and formic acid initiates the polymerization of acrylamide, which can reduce the residual amount of monomers; 2. In the process of stirring by the stirring blade in the reactor, since the viscosity of the solution will gradually change as the reaction proceeds, when the viscosity of the solution is too high, if the stirring area of the stirring blade on the solution is large, it is easy to make the rotation resistance of the stirring shaft too large. Therefore, the two movable rods are moved relative to each other to reduce the area of the winding blade, so that the stirring blade can keep moving in the solution with high viscosity to avoid damage caused by excessive resistance; 3. When the worm rotates and drives the worm wheel to rotate, the two movable rods are retracted, and at the same time, the two winding shafts wind up the winding blades, ensuring that the winding and the mutual movement of the two movable rods are synchronized, so that the winding blades can be in a flat state. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] Figure 1 It is a structural schematic diagram of a preparation device of a seawater-soluble heat-resistant polyacrylamide according to an embodiment of the present application; Explanation of the reference numerals: 1. stirring shaft; 2. stirring blade; 21. movable rod; 22. winding blade; 3. winding shaft; 4. worm gear; 5. worm; 6. driven bevel gear; 7. driving bevel gear. DETAILED DESCRIPTION
[0017] The following is combined with Figure 1 This application is described in further detail.
[0018] In the following embodiments: Preparation of a bifunctional initiator: Add concentrated sulfuric acid dropwise to a 30% hydrogen peroxide solution, using the concentrated sulfuric acid as a catalyst, and reducing the temperature to below 5°C; add 2,5-dimethyl-2,5-hexanediol to the mixed system, wherein the molar ratio of 2,5-dimethyl-2,5-hexanediol to hydrogen peroxide in the hydrogen peroxide solution is 1:1, and react at below 5°C for about 40 minutes, until a small amount of white solid precipitates in the late stage of the reaction, and then heat the temperature to 25°C and react for about 60 minutes. During the heating process, the amount of white solid precipitates increases, and then the temperature is reduced to below 5°C, and distilled water is added to the system and stirred for 10 minutes. The white solid product obtained by filtration is the bifunctional initiator.
[0019] Embodiment 1: The present application discloses a process for preparing a seawater-soluble heat-resistant polyacrylamide, comprising the following steps: 50 parts by weight of acrylamide, 5.5 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid and 0.8 parts by weight of 1-vinyl-2-pyrrolidone are added to a reactor, and then 150 parts by weight of deionized water are added to the reactor, stirring is performed during the addition process, the stirring is performed in the reactor, and the mixture is fully dissolved after mixing, and then sodium hydroxide is added to the reactor to adjust the pH value so that the pH value of the solution reaches 10.0; the solution in the reactor is cooled to -2°C, and nitrogen is introduced for deoxygenation for 15 minutes, and the nitrogen is continuously introduced during the nitrogen introduction process, and then an ion shielding agent, a chain transfer agent and an initiator are added, wherein the ion shielding agent is a metal ion shielding agent EDTA, and the amount of the metal ion shielding agent EDTA is 0.0% of the total solution. .001%~0.005%, the chain transfer agent is sodium formate, the amount of sodium formate is 0.001%~0.002% of the total solution, the amount of initiator is 0.1% of the total solution, stirring and conducting a closed reaction to obtain a viscous mixed solution; adding 10 parts by weight of granular sodium hydroxide and 5 parts by weight of sodium bisulfite to the mixed solution and then hydrolyzing it at a hydrolysis temperature of 90°C and a hydrolysis time of 6 hours to form a colloid; taking out the colloid and adding a high-temperature stabilizer, the high-temperature stabilizer is one of thiourea, amino acid, oxalate, citrate, and salicylate, and the amount of the high-temperature stabilizer is 0.3% of the total weight of the colloid, kneading the mud evenly, drying, crushing and sieving, the sieved particle size is 1~4mm, forming a seawater instant heat-resistant polyacrylamide.
[0020] The initiator includes an oxidant, a reducing agent and a bifunctional initiator. The oxidant is tert-butyl hydroperoxide, the reducing agent is formic acid, the bifunctional initiator is the bifunctional initiator prepared above, and the weight ratio of the oxidant, the reducing agent and the bifunctional initiator is 1:0.5:12.
[0021] Embodiment 2: The difference from Example 1 is that 50 parts by weight of acrylamide, 6 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid and 1 part by weight of 1-vinyl-2-pyrrolidone are added to the reactor, and then 200 parts by weight of deionized water are added to the reactor, and stirring is performed during the addition process. The stirring is performed in the reactor, and the mixture is fully dissolved after mixing. Then, sodium hydroxide is added to the reactor to adjust the pH value so that the pH value of the solution reaches 10.5; and the solution in the reactor is cooled to -1°C.
[0022] The initiator includes an oxidant, a reducing agent and a bifunctional initiator. The oxidant is tert-butyl hydroperoxide, the reducing agent is formic acid, the bifunctional initiator is the bifunctional initiator prepared above, and the weight ratio of the oxidant, the reducing agent and the bifunctional initiator is 1:0.5:14.
[0023] Embodiment 3: The difference from Example 1 is that 50 parts by weight of acrylamide, 6.5 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid and 1.2 parts by weight of 1-vinyl-2-pyrrolidone are added to the reactor, and then 250 parts by weight of deionized water are added to the reactor, and stirring is performed during the addition process. The stirring is performed in the reactor, and the mixture is fully dissolved after mixing. Then, sodium hydroxide is added to the reactor to adjust the pH value so that the pH value of the solution reaches 10.5; and the solution in the reactor is cooled to 0°C.
[0024] The initiator includes an oxidant, a reducing agent and a bifunctional initiator. The oxidant is tert-butyl hydroperoxide, the reducing agent is formic acid, the bifunctional initiator is the bifunctional initiator prepared above, and the weight ratio of the oxidant, the reducing agent and the bifunctional initiator is 1:0.5:16.
[0025] Embodiment 4: The difference from Example 1 is that 50 parts by weight of acrylamide, 6.5 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid and 1.2 parts by weight of 1-vinyl-2-pyrrolidone are added to the reactor, and then 300 parts by weight of deionized water are added to the reactor, and stirring is performed during the addition process. The stirring is performed in the reactor, and the mixture is fully dissolved after mixing. Then, sodium hydroxide is added to the reactor to adjust the pH value so that the pH value of the solution reaches 11; and the solution in the reactor is cooled to 0°C.
[0026] The initiator includes an oxidant, a reducing agent and a bifunctional initiator. The oxidant is tert-butyl hydroperoxide, the reducing agent is formic acid, the bifunctional initiator is the bifunctional initiator prepared above, and the weight ratio of the oxidant, the reducing agent and the bifunctional initiator is 1:0.5:18.
[0027] Comparative Example 1: The difference from Example 1 is that after the colloid is taken out, no high temperature stabilizer is added, and it is directly dried, crushed and sieved to obtain the product.
[0028] Comparative Example 2: The difference from Example 1 is that the initiator includes an oxidant, a reductant and an azo initiator, the oxidant is ammonium persulfate, the reductant is ferrous sulfate, the azo initiator is azobisisobutyronitrile, and the weight ratio of the oxidant, the reductant and the azo initiator is 1:0.5:15.
[0029] Comparative Example 3: The difference from Example 1 is that 50 parts by weight of acrylamide, 2 parts by weight of 2-acrylamide-2-methylpropanesulfonic acid and 0.8 parts by weight of 1-vinyl-2-pyrrolidone are added to the reactor, and then 150 parts by weight of deionized water are added to the reactor, and stirring is performed during the addition process.
[0030] The granules obtained in Examples 1 to 4 and Comparative Examples 1 to 3 were dissolved, filtered after dissolution, and the undissolved amount obtained by drying the filtrate was weighed. The filtered solution was diluted to obtain a test solution, and a viscometer was used to test the viscosity of the test solution at different temperatures after 2 hours. The different temperatures were set to 50°C, 70°C, 90°C and 120°C, respectively. The viscosity of the test solution was tested at 50°C, 70°C, 90°C and 120°C after 60 days, and the test data shown in Table 1 were obtained.
[0031] Specifically, 0.2g of the above sample is added to a solution with a mineralization degree of 32631mg / L, in which the total amount of calcium and magnesium ions is 1572mg / L. When preparing, first place 500g of the solution in a 1L volumetric flask, then stir the solution at a stirring speed of 300r / min, then sprinkle the sample into the solution continuously and evenly within 1min, and then stop and filter after stirring for 10s. The filtrate is placed in a drying oven at 120℃ and dried for 20min, and then weighed to obtain the undissolved amount. The filtered solution is then diluted with a solution with a mineralization degree of 32631mg / L to dilute it into a solution with a concentration of 30%, and placed in a water bath at different temperatures for insulation. During the test, a Brookfield viscometer, model DVII+ or DVIII, is used for viscosity testing.
[0032] Table 1 From the data in Table 1, it can be seen that the remaining undissolved amount in Comparative Example 3 is at least 30% higher than the undissolved amount in Examples 1-4, so it can be seen that 2-acrylamide-2-methylpropanesulfonic acid is a strongly polar anionic functional monomer, and the amount added can make polyacrylamide have better hydrophilicity and reduce the sensitivity to salt in seawater; the amount of residual monomers in Comparative Example 2 is relatively large relative to the amount of residual monomers in Examples 1-4, so the initiator composited by an oxidant, a reductant and a bifunctional initiator in the present application better initiates a chain reaction and reduces the amount of residual acrylamide monomer; Compared with Examples 1-4, the viscosity in Comparative Example 1 gradually decreases at a temperature, and the greater the viscosity decreases, the lower the viscosity value is when the temperature is greater than 70°C.
[0033] The embodiments of the present application also disclose a device for preparing seawater instant heat-resistant polyacrylamide, comprising a reactor used in the above-mentioned embodiments 1-4 and comparative examples 1-3, wherein a stirring shaft 1 rotatably connected to the reactor is provided in the reactor, the stirring shaft 1 is vertically arranged, and two stirring blades 2 are arranged on the stirring shaft 1, and the stirring blades 2 rotate with the stirring shaft 1 to stir the solution in the reactor.
[0034] The stirring blade 2 includes two movable rods 21 and a reeling blade 22 disposed between the two movable rods 21. One end of the movable rod 21 is rotatably connected to the stirring shaft 1, and the movable rod 21 is disposed horizontally with the rotation axis of the stirring shaft 1. The two movable rods 21 in one stirring blade 2 approach or move away from each other during vertical rotation. When the two movable rods 21 approach each other, the reeling blade 22 between the two movable rods 21 shrinks toward the inside of the movable rod 21, so that the area of the reeling blade 22 between the two movable rods 21 is reduced. In the process of stirring the solution in the reactor by the stirring blade 2, since the viscosity of the solution gradually changes as the reaction proceeds, when the viscosity of the solution is too large, if the stirring area of the stirring blade 2 on the solution is large, it is easy to make the rotation resistance of the stirring shaft 1 too large. Therefore, the two movable rods 21 move relative to each other to reduce the area of the reeling blade 22, so that the stirring blade 2 can keep moving in the solution with high viscosity to avoid damage caused by excessive resistance.
[0035] A winding shaft 3 is arranged inside the movable rod 21. The winding shaft 3 is arranged to be conical as a whole, and the diameter of the end of the winding shaft 3 close to the stirring shaft 1 is smaller than the diameter of the end of the winding shaft 3 away from the stirring shaft 1. The length direction of the movable rod 21 is the same as the length direction of the movable rod 21, and the winding shaft 3 is rotatably connected to the movable rod 21. When the winding shaft 3 rotates, the fan-shaped winding blade 22 between the two movable rods 21 can be wound on the winding shaft 3. A worm gear 4 is fixedly arranged at one end of the movable rod 21, and the worm gear 4 is rotatably connected to the stirring shaft 1, so that the movable rod 21 is rotatably connected to the stirring shaft 1 through the worm gear 4. Each movable rod 21 is connected to a worm gear 4. The two movable rods 21 on the same stirring blade 2 have two worm gears 4, and the rotation directions of the two worm gears 4 are opposite. Each worm gear 4 is connected to a worm 5, and the two worm gears 5 are coaxially fixedly arranged, and the worm gear 5 is rotatably connected to the stirring shaft 1. The spiral directions of the two worm gears 5 corresponding to the two worm gears 4 are opposite, so that when the two worm gears 5 rotate coaxially, the two worm gears 4 can be relatively close to or away from each other. At the same time, a driven bevel gear 6 is coaxially fixedly arranged at one end of the winding shaft 3, and a driving bevel gear 7 is fixedly arranged inside the stirring shaft 1. The driving bevel gear 7 is coaxially arranged with the worm gear 4. When the worm gear 4 rotates, the driven bevel gear 6 rotates around the center of the driving bevel gear 7, so that the driven bevel gear 6 rolls on the driving bevel gear 7, and the winding shaft 3 can reel in the winding blade 22.
[0036] The above are all preferred embodiments of the present application, and the protection scope of the present application is not limited thereto. Therefore, any equivalent changes made according to the structure, shape, and principle of the present application should be included in the protection scope of the present application.
Claims
1. A process for preparing a seawater-soluble heat-resistant polyacrylamide, characterized in that: The method comprises the following steps: adding acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, 1-vinyl-2-pyrrolidone and deionized water into a reaction kettle, mixing and fully dissolving them, and then adjusting the pH value to 10.0-11.0; The solution in the reactor was cooled to -2 to 0°C and nitrogen was introduced for deoxygenation for 15 minutes; Then, an ion shielding agent, a chain transfer agent and an initiator are added, stirred and reacted in a closed manner to obtain a viscous mixed solution; Add granular sodium hydroxide and sodium bisulfite to the mixed solution and then hydrolyze at a temperature of 90°C for 6 hours to form a colloid; After the colloid is taken out, a high temperature stabilizer is added, and the mud is kneaded evenly, dried, crushed, and sieved to form a seawater instant heat-resistant polyacrylamide; The high temperature stabilizer is one of thiourea, amino acid, oxalate, citrate and salicylate.
2. The process for preparing the seawater-soluble heat-resistant polyacrylamide according to claim 1, characterized in that: The weight ratio of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, 1-vinyl-2-pyrrolidone and deionized water is 50:5.5-6.5:0.8-1.2:150-300.
3. The process for preparing the seawater instant heat-resistant polyacrylamide according to claim 1, characterized in that: The weight ratio of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, 1-vinyl-2-pyrrolidone and deionized water is 50:6:1:
200.
4. The process for preparing the seawater instant heat-resistant polyacrylamide according to claim 1, characterized in that: The initiator comprises an oxidant, a reducing agent and a bifunctional initiator, and the weight ratio of the oxidant, the reducing agent and the bifunctional initiator is 1:0.5:12-20.
5. The process for preparing the seawater-soluble heat-resistant polyacrylamide according to claim 4, characterized in that: The oxidizing agent is tert-butyl hydroperoxide, and the reducing agent is formic acid.
6. The process for preparing the seawater-soluble heat-resistant polyacrylamide according to claim 4, characterized in that: The preparation steps of the bifunctional initiator include adding a 30% hydrogen peroxide solution and adding concentrated sulfuric acid dropwise, and then lowering the temperature to below 5°C; adding 2,5-dimethyl-2,5-hexanediol to the mixed system, reacting at below 5°C for about 40 minutes, until a small amount of white solid precipitates in the late stage of the reaction, and then heating the temperature to 25°C for about 60 minutes. During the heating process, the white solid precipitates increase, and the bifunctional initiator is obtained by filtering.
7. The process for preparing the seawater-soluble heat-resistant polyacrylamide according to claim 1, characterized in that: The chain transfer agent is one of sodium formate, sodium hypophosphite, isopropyl alcohol and thioglycolic acid.
8. A seawater-soluble heat-resistant polyacrylamide, characterized in that: The polyacrylamide is prepared by the preparation process of the seawater-soluble heat-resistant polyacrylamide described in any one of claims 1 to 7.
9. A preparation device for seawater instant heat-resistant polyacrylamide, characterized in that: The reactor is provided with a rotating stirring shaft, on which two stirring blades are arranged. The stirring blades include two movable rods and a winding blade arranged between the two movable rods. One end of the two movable rods is rotatably connected to the stirring shaft, and a winding shaft is arranged inside the movable rod. Both sides of the winding blade are rolled up on the winding shaft.
10. The preparation device of the seawater instant heat-resistant polyacrylamide according to claim 9, characterized in that: A worm gear is fixedly provided at one end of the movable rod, and the worm gear is rotatably connected to the stirring shaft. The winding shaft is rotatably connected to the inside of the movable rod, and is connected to the driven bevel gear at one end of the movable rod. An active bevel gear is fixedly provided in the stirring shaft, and the active bevel gear is coaxially arranged with the worm gear. The active bevel gear is meshed with the driven bevel gear. The worm gears on the two movable rods are respectively connected to a worm, and the two worms are coaxially and fixedly connected, and the worm is rotatably connected in the stirring shaft.