Elastic gel particles and method for making same

Abstract

The present application provides a kind of elastic gel particles and its preparation method.The elastic gel particles are prepared by silicate, crosslinking agent, sulfonated phenolic resin, the gel prepared under the action of acid catalyst of polyvinyl alcohol is granulated, and the particle size is 1 × 10 1 To 3 × 10 6 Nm.The gel for preparing the elastic gel particles has a storage modulus of 780 to 1953 Pa, a temperature resistance of up to 130 DEG C, a mineralization resistance of up to 214812.46 mg / L, good toughness and stability: after soaking at 130 DEG C, 214812.46 mg / L of mineralization for 90 days, the deformation recovery rate of 5 times extrusion is 60 to 87%, the dehydration rate is 15% to 30%, and the volume shrinkage rate is 29% to 45%, so that the elastic gel particles have good and long-term stable plugging effect.

Description

Technical Field

[0001] This invention belongs to the field of oilfield chemical technology, and particularly relates to an elastic gel particle and its preparation method. Background Technology

[0002] Western my country's oilfields are mostly high-temperature, high-salinity fractured-vuggy reservoirs with well-developed millimeter-scale fractures, making formation heterogeneity particularly prominent. The presence of large fractures and caverns leads to severe water channeling along large and micro fractures, resulting in low sweep efficiency and low waterflood recovery. Particulate profile control agents are widely available, economical, and effective, especially for plugging large channels in fractured-vuggy reservoirs. Furthermore, since they are already finished products at the surface, they do not require reaction or cross-linking under formation conditions, partially avoiding a series of adverse effects from formation factors. However, the application of particulate profile control agents for plugging fractures and large channels in fractured-vuggy reservoirs faces challenges such as injection difficulties, poor temperature and salt resistance, and insufficient deformation and suspension capabilities. Existing particle types are mainly divided into inorganic particles and cross-linked polymer particles, which are currently widely used particle profile control agents in oilfield development. However, they still face many problems when facing the harsh reservoir environment of oilfields. Inorganic particles have high strength and can remain stable for a long time under high temperature and high salinity conditions, but their high density makes them difficult to suspend and carry, making particle injection difficult and easily clogging water wells, causing operational accidents. On the other hand, cross-linked polymer particles have poor temperature and salt resistance, are prone to degradation and shrinkage in high temperature environments, and these polymers have high molecular weights, making it difficult to formulate high-concentration gelling solutions. Therefore, the strength of the gel formed is limited, and the strength of the particles prepared from it is also limited, making it difficult to meet the requirements for use. Summary of the Invention

[0003] To address the problems of existing particulate profile control agents, such as high density, poor deformation ability, insufficient temperature and salt resistance, and low strength, the present invention aims to provide an elastic gel particle with temperature resistance up to 130℃, salt resistance up to 210,000 mg / L, high strength, strong elasticity and deformation ability, low shrinkage rate in saline water, easy suspension, and easy injection, as well as its preparation method. This elastic gel particle, as a particulate profile control agent, provides support for channel adjustment in high-temperature, high-salt fractured-vuggy reservoirs.

[0004] To achieve the above objectives, one aspect of the present invention provides a method for preparing elastic gel particles, comprising the following steps:

[0005] 1) Silicate and water are mixed to obtain the first dispersion;

[0006] 2) Mix the crosslinking agent, sulfonated phenolic resin, and the first dispersion to obtain the second dispersion;

[0007] 3) Mix polyvinyl alcohol and the second dispersion to obtain a third dispersion;

[0008] 4) Mix the acid catalyst and the third dispersion, react to obtain a gel, granulate to obtain the elastic gel particles.

[0009] According to a specific embodiment of the present invention, the elastic gel particles are 100% by mass, the amount of silicate is 2 wt% to 6 wt%, the amount of crosslinking agent is 0.3 wt% to 0.7 wt%, the amount of sulfonated phenolic resin is 1 wt% to 3 wt%, the amount of polyvinyl alcohol is 4 wt% to 10 wt%, the amount of acid catalyst is 0.5 wt% to 1.5 wt%, and the amount of water is 78.8 wt% to 92.2 wt%.

[0010] Preferably, the elastic gel particles account for 100% by mass, the amount of silicate is 2 wt% to 4 wt%, the amount of crosslinking agent is 0.3 wt% to 0.5 wt%, the amount of sulfonated phenolic resin is 1 wt% to 2 wt%, the amount of polyvinyl alcohol is 4 wt% to 10 wt%, the amount of acid catalyst is 1 wt%, and the amount of water is 82.5 wt% to 88.7 wt%.

[0011] According to one specific embodiment of the present invention, the silicate is sodium-based bentonite; and / or

[0012] The crosslinking agent is selected from aldehyde crosslinking agents and / or hexamethylenetetramine; and / or

[0013] The acid catalyst is an inorganic acid and / or an organic acid; and / or

[0014] The water has a mineralization of less than 1000 mg / L;

[0015] Preferably, the aldehyde crosslinking agent is selected from at least one of formaldehyde, paraformaldehyde, glyoxal, glutaraldehyde, and terephthalaldehyde; and / or

[0016] The organic acids include haloacetic acids and / or alkylbenzene sulfonic acids;

[0017] Preferably, the inorganic acid is hydrochloric acid and / or sulfuric acid; and / or the haloacetic acid is chloroacetic acid; and / or the alkylbenzene sulfonic acid is p-toluenesulfonic acid.

[0018] According to a specific embodiment of the present invention, the sulfonated phenolic resin has a sulfur content of 8 wt% to 10 wt%; and / or a solid content of not less than 90 wt%; and / or

[0019] The degree of alcoholysis of the polyvinyl alcohol is 87% to 89%; and / or the molecular weight is 100,000 to 1,200,000;

[0020] Preferably, the polyvinyl alcohol is polyvinyl alcohol 2488.

[0021] According to a specific embodiment of the present invention, in step 4), the reaction conditions are to stand at 22°C to 25°C for 4 to 8 hours.

[0022] According to a specific embodiment of the present invention, in step 4), the strength of the gel reaches level I based on the visual code evaluation method; and / or

[0023] During the granulation process, an alkaline solution is sprayed onto the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral.

[0024] Preferably, the alkaline solution is selected from at least one of sodium hydroxide solution, sodium carbonate solution, triethanolamine and sodium bicarbonate solution;

[0025] Preferably, the alkaline solution is selected from at least one of sodium hydroxide aqueous solution, sodium carbonate aqueous solution, triethanolamine, and sodium bicarbonate aqueous solution;

[0026] Preferably, the solute mass fraction of the sodium hydroxide aqueous solution, sodium carbonate aqueous solution, and sodium bicarbonate aqueous solution is 1 wt%.

[0027] According to a specific embodiment of the present invention, steps 1) to 4) are all performed by stirring and mixing;

[0028] Preferably, the stirring speed in steps 1) to 4) is independently 300 rpm to 600 rpm.

[0029] The visual code evaluation method described in this invention refers to the classification of sealant gel strength (GSC) into 10 grades based on visual inspection results, as proposed by Sydansk et al. Grade I refers to the gel strength of a rigid gel whose surface does not deform upon inversion.

[0030] The second invention provides elastic gel particles prepared by the method described in the first invention.

[0031] According to a specific embodiment of the present invention, the particle size of the elastic gel particles is 1×10⁻⁶. 1 nm to 3×10 6 nm.

[0032] The application of elastic gel particles prepared by the method according to one of the present inventions or the elastic gel particles according to the second of the present invention in high-temperature and high-salinity fractured-vuggy reservoirs, especially in the application of flow channel adjustment in high-temperature and high-salinity fractured-vuggy reservoirs.

[0033] According to a specific embodiment of the present invention, the high temperature is not lower than 130°C; and / or

[0034] The term "high salt" refers to a mineralization degree of not less than 210,000 mg / L.

[0035] The beneficial effects of this invention are:

[0036] To address the problems of high density, poor deformation ability, insufficient temperature and salt resistance, and low strength in existing particulate profile control agents, the elastic gel particles provided by this invention are obtained by granulation of a gel prepared from silicate, crosslinking agent, sulfonated phenolic resin, and polyvinyl alcohol under the action of an acid catalyst. The gel particles prepared from this elastic gel particles have a storage modulus of 780 to 1953 Pa, a temperature resistance of up to 130℃, a mineralization resistance of up to 214812.46 mg / L, good toughness, and good stability. After soaking for 90 days at 130℃ and a mineralization of 214812.46 mg / L, the deformation recovery rate after 5 extrusions is 60% to 87%, the dehydration rate is 15% to 30%, and the volume shrinkage rate is 29% to 45%. They can maintain their stability at 130℃ and a mineralization of 214812.46 mg / L, thus ensuring a good and long-term stable profile control effect. The elastic gel particles prepared by this invention have low density and good suspension in highly salinized formation water, making them easy to carry and inject into deep formations. The preparation method provided by this invention can produce elastic gel particles of different particle sizes at room temperature, and the process is simple, convenient for storage, transportation, and field application. Detailed Implementation

[0037] 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.

[0038] The sulfonated phenolic resins used in Examples 1 to 6, Comparative Example 1, and Comparative Example 3 were all sulfonated phenolic resins SMP-I, with a solid content ≥90% and a sulfur content of 8wt% to 10wt%.

[0039] The polyvinyl alcohol used in Examples 1 to 6 and Comparative Examples 1 to 3 was polyvinyl alcohol 2488 with a molecular weight of 117,000.

[0040] Example 1

[0041] 1) Weigh 40g of sodium bentonite and 846g of water and mix them. Stir at 500rpm for 2 hours to disperse the sodium bentonite evenly in the water and obtain the first dispersion.

[0042] 2) Mix the first dispersion with 4g of glyoxal and 20g of sulfonated phenolic resin SMP-Ⅰ, and stir at 500rpm for 30min to fully dissolve the glyoxal and sulfonated phenolic resin SMP-Ⅰ to obtain the second dispersion.

[0043] 3) Mix 80g of polyvinyl alcohol 2488 with the second dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the third dispersion.

[0044] 4) Add 10g of p-toluenesulfonic acid to the third dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 6h to obtain a gel. The gel strength is judged to reach Grade I by visual code evaluation method. The obtained gel is ground and granulated by granulator. During the granulation process, 2262.5g of 1wt% NaOH aqueous solution is sprayed evenly on the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral, thus obtaining elastic gel particles with a particle size of 10 to 300,000nm.

[0045] Example 2

[0046] 1) Weigh 40g of sodium bentonite and 825g of water and mix them. Stir at 500rpm for 2 hours to disperse the sodium bentonite evenly in the water and obtain the first dispersion.

[0047] 2) Mix the first dispersion with 5g of glyoxal and 20g of sulfonated phenolic resin SMP-Ⅰ, and stir at 500rpm for 30min to fully dissolve the glyoxal and sulfonated phenolic resin SMP-Ⅰ to obtain the second dispersion.

[0048] 3) Mix 100g of polyvinyl alcohol 2488 with the second dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the third dispersion.

[0049] 4) Add 10g of p-toluenesulfonic acid to the third dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 6h to obtain a gel. The gel strength is judged to reach Grade I by visual code evaluation method. The obtained gel is ground and granulated by granulator. During the granulation process, 2262.5g of 1wt% NaOH aqueous solution is sprayed evenly on the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral, thus obtaining elastic gel particles with a particle size of 10 to 300,000nm.

[0050] Example 3

[0051] 1) Weigh 40g of sodium bentonite and 887g of water and mix them. Stir at 500rpm for 2 hours to disperse the sodium bentonite evenly in the water and obtain the first dispersion.

[0052] 2) Mix the first dispersion with 3g of glyoxal and 20g of sulfonated phenolic resin SMP-Ⅰ, and stir at 500rpm for 30min to fully dissolve the glyoxal and sulfonated phenolic resin SMP-Ⅰ to obtain the second dispersion.

[0053] 3) Mix 40g of polyvinyl alcohol 2488 with the second dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the third dispersion.

[0054] 4) Add 10g of p-toluenesulfonic acid to the third dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 6.5h to obtain a gel. The gel strength is judged to reach Grade I by visual code evaluation method. The obtained gel is ground and granulated by granulator. During the granulation process, 2262.5g of 1wt% NaOH aqueous solution is sprayed evenly on the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral, thus obtaining elastic gel particles with a particle size of 10 to 300000nm.

[0055] Example 4

[0056] 1) Weigh 20g of sodium bentonite and 866g of water and mix them. Stir at 500rpm for 2 hours to disperse the sodium bentonite evenly in the water and obtain the first dispersion.

[0057] 2) Mix the first dispersion with 4g of glyoxal and 20g of sulfonated phenolic resin SMP-Ⅰ, and stir at 500rpm for 30min to fully dissolve the glyoxal and sulfonated phenolic resin SMP-Ⅰ to obtain the second dispersion.

[0058] 3) Mix 80g of polyvinyl alcohol 2488 with the second dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the third dispersion.

[0059] 4) Add 10g of p-toluenesulfonic acid to the third dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 5h to obtain a gel. The gel strength is judged to reach Grade I by visual code evaluation method. The obtained gel is ground and granulated using a granulator. During the granulation process, 2262.5g of 1wt% NaOH aqueous solution is sprayed evenly on the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral, thus obtaining elastic gel particles with a particle size of 10 to 300,000nm.

[0060] Example 5

[0061] 1) Weigh 40g of sodium bentonite and 846g of water and mix them. Stir at 500rpm for 2 hours to disperse the sodium bentonite evenly in the water and obtain the first dispersion.

[0062] 2) Mix the first dispersion with 4g of glyoxal and 20g of sulfonated phenolic resin SMP-Ⅰ, and stir at 500rpm for 30min to fully dissolve the glyoxal and sulfonated phenolic resin SMP-Ⅰ to obtain the second dispersion.

[0063] 3) Mix 80g of polyvinyl alcohol 2488 with the second dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the third dispersion.

[0064] 4) Add 10g of chloroacetic acid to the third dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 8h to obtain a gel. The gel strength is judged to reach Grade I by visual code evaluation method. The obtained gel is ground and granulated using a granulator. During the granulation process, 2262.5g of 1wt% NaOH aqueous solution is sprayed evenly on the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral, thus obtaining elastic gel particles with a particle size of 10 to 300,000nm.

[0065] Example 6

[0066] 1) Weigh 40g of sodium bentonite and 856g of water and mix them. Stir at 500rpm for 2 hours to disperse the sodium bentonite evenly in the water and obtain the first dispersion.

[0067] 2) Mix the first dispersion with 4g of glyoxal and 10g of sulfonated phenolic resin SMP-Ⅰ, and stir at 500rpm for 30min to fully dissolve the glyoxal and sulfonated phenolic resin SMP-Ⅰ to obtain the second dispersion.

[0068] 3) Mix 80g of polyvinyl alcohol 2488 with the second dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the third dispersion.

[0069] 4) Add 10g of p-toluenesulfonic acid to the third dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 4h to obtain a gel. The gel strength is judged to reach Grade I by visual code evaluation method. The obtained gel is ground and granulated using a granulator. During the granulation process, 2262.5g of 1wt% NaOH aqueous solution is sprayed evenly on the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral, thus obtaining elastic gel particles with a particle size of 10 to 300,000nm.

[0070] Comparative Example 1

[0071] 1) Weigh 4g of glyoxal, 20g of sulfonated phenolic resin SMP-Ⅰ and 886g of water and mix them. Stir at 500rpm for 30min to fully dissolve the glyoxal and sulfonated phenolic resin SMP-Ⅰ to obtain the first dispersion.

[0072] 2) Mix 80g of polyvinyl alcohol 2488 with the first dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the second dispersion.

[0073] 3) Add 10g of p-toluenesulfonic acid to the second dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 4.5h to obtain a gel. The gel strength is judged to reach Grade I by visual code evaluation method. The obtained gel is ground and granulated by granulator. During the granulation process, 2262.5g of 1wt% NaOH aqueous solution is sprayed evenly on the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral, thus obtaining elastic gel particles with a particle size of 10 to 300000nm.

[0074] Comparative Example 2

[0075] 1) Weigh 40g of sodium bentonite and 866g of water and mix them. Stir at 500rpm for 2 hours to disperse the sodium bentonite evenly in the water and obtain the first dispersion.

[0076] 2) Mix the first dispersion with 4g of glyoxal and stir at 500rpm for 30min to fully dissolve the glyoxal and obtain the second dispersion.

[0077] 3) Mix 80g of polyvinyl alcohol 2488 with the second dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the third dispersion.

[0078] 4) Add 10g of p-toluenesulfonic acid to the third dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 3h to obtain a gel. The gel strength is judged to reach Grade I by visual code evaluation method. The obtained gel is ground and granulated using a granulator. During the granulation process, 2262.5g of 1wt% NaOH aqueous solution is sprayed evenly on the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral, thus obtaining elastic gel particles with a particle size of 10 to 300,000nm.

[0079] Comparative Example 3

[0080] 1) Weigh 40g of sodium bentonite and 846g of water and mix them. Stir at 500rpm for 2 hours to disperse the sodium bentonite evenly in the water and obtain the first dispersion.

[0081] 2) Mix the first dispersion with 4g of glyoxal and 20g of sulfonated phenolic resin SMP-Ⅰ, and stir at 500rpm for 30min to fully dissolve the glyoxal and sulfonated phenolic resin SMP-Ⅰ to obtain the second dispersion.

[0082] 3) Mix 80g of polyvinyl alcohol 2488 with the second dispersion and stir at 500rpm for 2h to fully dissolve the polyvinyl alcohol 2488 and obtain the third dispersion.

[0083] 4) Add 10g of p-toluenesulfonic acid to the third dispersion and stir at 300rpm for 5min. After the p-toluenesulfonic acid is fully dissolved, a gelling solution is prepared. Let it stand at room temperature for 6h to obtain a gel. The gelling strength is judged to reach Grade I by visual code evaluation method. The obtained gel is then ground and pulverized using a granulator to obtain elastic gel particles with a particle size of 10 to 300,000nm.

[0084] Performance evaluation of elastic gel particles

[0085] For ease of experimentation and accuracy of results, the gelation time, storage modulus, room temperature toughness, toughness after 90 days of high-temperature, high-salt immersion, dehydration rate after 30 days of high-temperature, high-salt immersion, volume shrinkage rate after 30 days of high-temperature, high-salt immersion, dehydration rate after 90 days of high-temperature, high-salt immersion, and volume shrinkage rate after 90 days of high-temperature, high-salt immersion were directly measured to evaluate the performance of the gels. Furthermore, since the elastic gel particles are obtained by physical granulation of the gel, the performance of the gel can represent the performance of the elastic gel particles. It should be noted that the high-temperature, high-salt environment (specifically, 130℃, saline solution with a mineralization of 214812.46 mg / L) refers to the conditions for experimental treatment of the gel; all experimental data were measured at room temperature (25℃); before the experiment, a 1 wt% NaOH aqueous solution was sprayed evenly onto the surface of the gel to be tested to adjust the pH to neutral.

[0086] The following is the method for preparing 1L of brine with a mineralization of 214812.46mg / L in the experiments measuring the toughness, dehydration rate, volume shrinkage rate, and volume shrinkage rate of elastic gel particles after 90 days of high-temperature and high-salt immersion, 30 days of high-temperature and high-salt immersion, 30 days of high-temperature and high-salt immersion, 90 days of high-temperature and high-salt immersion, and 90 days of high-temperature and high-salt immersion:

[0087] i. Take 500 mL of distilled water, weigh out the amounts of CaCl2, MgCl2·6H2O, Na2SO4, NaHCO3, KI, KBr and NaCl according to the amounts of various salts listed in Table 1, add them to the distilled water, and stir thoroughly to dissolve them to obtain the salt solution to be diluted.

[0088] Table 1. Amounts of various salts required to prepare 1L of brine

[0089]

[0090]

[0091] ii. Transfer the salt solution to be diluted obtained in i to a 1L volumetric flask, add distilled water to make up to 1L, and obtain 1L of saline solution with a mineralization of 214812.46mg / L. Its specific composition is shown in Table 2.

[0092] Table 2. Composition of brine with a mineralization of 214812.46 mg / L

[0093] project Content (mg / L) <![CDATA[Ca 2+ ]]> 11598.6 <![CDATA[Mg 2+ ]]> 1224.5 <![CDATA[K + +That + ]]> 69831.7 <![CDATA[Cl - ]]> 131489.2 <![CDATA[SO4 2- ]]> 264.3 <![CDATA[I - ]]> 7.43 <![CDATA[Br - ]]> 251.43 <![CDATA[HCO3 - ]]> 145.3 Total mineralization 214812.46 Water type <![CDATA[CaCl2]]>

[0094] The specific measurement method is as follows:

[0095] (1) Determination of gelation time for preparing elastic gel particles

[0096] First, a 1 wt% NaOH aqueous solution was uniformly sprayed onto the surface of the gels prepared in Examples 1 to 6 and Comparative Examples 1 to 3 to adjust the pH to neutral. Then, the gel strength (GSC) of the plugging agent was evaluated using a visual code method (Sydansk et al., which classifies the gel strength into 10 levels based on visual inspection). The time when the gel strength of the gels prepared in Examples 1 to 6 and Comparative Examples 1 to 3 reached level I was determined by referring to Table 3, which is the gelation time. The specific results are shown in Table 4.

[0097] Table 3. Gel Strength Code Standard

[0098]

[0099]

[0100] (2) Determination of the storage modulus of the gel used to prepare elastic gel particles

[0101] First, the pH of the gels prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was uniformly sprayed with a 1 wt% NaOH aqueous solution to adjust it to neutral. Then, the storage modulus of the gels was determined using a MARS III high-temperature and high-pressure acid-resistant rheometer, referring to the standard SY-T6296-2013 "Determination of Strength of Oilfield Gels - Rheological Parameter Method", at room temperature (25°C) and atmospheric pressure (0.1 MPa). The specific results are shown in Table 4.

[0102] Table 4. Gel gelation time and storage modulus for preparing elastic gel particles

[0103] Serial Number gel forming time / h Storage modulus of gel / Pa Example 1 6 1275 Example 2 6 1953 Example 3 6.5 859 Example 4 5 780 Example 5 8 1112 Example 6 4 1320 Comparative Example 1 4.5 600 Comparative Example 2 3 1413 Comparative Example 3 6 1250

[0104] Table 4 shows that the gelation time of the elastic gel particles prepared in Examples 1 to 6 was 4 to 8 hours, and the storage modulus was 780 to 1953 Pa. The storage modulus of the elastic gel particles prepared in Comparative Example 1 was only 600 Pa. The gelation time of the elastic gel particles prepared in Comparative Example 2 was 3 hours. From the formulation, Comparative Example 1 lacked sodium bentonite compared to Example 1, and Comparative Example 2 lacked sulfonated phenolic resin compared to Example 1. This indicates that the lack of certain raw materials affects the elastic modulus of the gel, resulting in a low elastic modulus that makes it prone to breakage and affects the sealing strength.

[0105] (3) Determination of the toughness of the gel used to prepare elastic gel particles at room temperature (i.e., 25°C) (i.e., the deformation recovery rate η1 of the gel after 5 extrusions at room temperature).

[0106] First, the surface of the gels prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was uniformly sprayed with a 1 wt% NaOH aqueous solution to adjust the pH to neutral. Then, the gels were cut into cylindrical gel blocks with a diameter of 2 cm and a height of 3 cm. The initial height of the cylindrical gel blocks was recorded as L0. Using a HY-01 microcomputer electronic compression tester, the gel blocks were compressed downwards at a speed of 12.5 mm / min until the height of the cylindrical gel blocks became 1 cm. The pressure was then released until the gel blocks no longer recovered their deformation. After compression and recovery, the process was repeated 5 times. The height recovered after deformation was measured and recorded as L1.

[0107] pass (Formula I) The deformation recovery rate η1 after 5 compressions at room temperature is calculated, and the specific results are shown in Table 5.

[0108] (4) The toughness of the gel after immersion in high temperature and high salt for 90 days (i.e., the deformation recovery rate η2 after 5 extrusions at room temperature (i.e., 25℃) after immersion in salt water at 130℃ and mineralization of 214812.46 mg / L for 90 days) was determined.

[0109] First, the surface of the gels prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was uniformly sprayed with a 1 wt% NaOH aqueous solution to adjust the pH to neutral. Then, the gel blocks were placed in beakers containing saline solution with a mineralization of 214812.46 mg / L, ensuring that the gel blocks were completely submerged in the saline solution. After placing the beakers in a constant temperature oven at 130°C for 90 days, the soaked gel blocks were removed from each beaker and cut into cylindrical gel blocks with a diameter of 2 cm and a height of 3 cm. The initial height of the cylindrical gel blocks was recorded as L0. Using a HY-01 microcomputer electronic compression tester, the gel blocks were compressed downwards at a speed of 12.5 mm / min until the height of the cylindrical gel blocks became 1 cm. The pressure was then released until the gel blocks no longer recovered their deformation. After compression and recovery, this process was repeated 5 times. The height recovered after deformation was measured and recorded as L2.

[0110] pass Formula II was used to calculate the deformation recovery rate η1 after 5 compressions at room temperature after 90 days of soaking. The specific results are shown in Table 5.

[0111] Table 5. Toughness of the gel used to prepare elastic gel particles after immersion in a high-temperature, high-salt environment at room temperature.

[0112]

[0113] The data in Table 5 show that the elastic gel particles prepared in Examples 1 to 6 exhibited a deformation recovery rate of 85% to 96.5% after 5 extrusions at room temperature; after soaking for 90 days at 130°C with a salinity of 214812.46 mg / L, the deformation recovery rate after 5 extrusions was 60% to 87%, indicating that the elastic gel particles prepared in Examples 1 to 6 possess good toughness after soaking at room temperature or in saline solution at 130°C with a salinity of 214812.46 mg / L. The elastic gel particles prepared in Comparative Example 1 showed signs of breakage after soaking at room temperature and in saline solution at 130°C with a salinity of 214812.46 mg / L, indicating poor toughness. The elastic gel particles prepared in Comparative Example 2, after soaking in saline solution at 130°C with a salinity of 214812.46 mg / L for 90 days, showed a deformation recovery rate of only 30% after 5 extrusions at room temperature (i.e., 25°C), indicating poor toughness.

[0114] (5) Dehydration rate and volume shrinkage rate of the gel prepared by high-temperature and high-salt soaking for 30 days in elastic gel particles

[0115] First, the surface of the gels prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was uniformly sprayed with a 1 wt% NaOH aqueous solution to adjust the pH to neutral. Then, the gels were cut into cubes with an edge length of 5 cm, and their initial mass was recorded as m0 and their initial volume as V0 (i.e., 125 cm³). 3Place the gel blocks into beakers containing saline solution with a mineralization of 214812.46 mg / L, ensuring the gel blocks are completely submerged. After placing the beakers in a constant temperature oven at 130℃ for 30 days, remove the soaked gel blocks from each beaker, rinse them three times with deionized water, wipe the surface of the rinsed gel blocks with absorbent paper, and cool them to room temperature (i.e., 25℃). Then weigh and measure their volume, and record the mass m1 and volume V1 of the gel blocks after water loss.

[0116] pass (Formula III) calculates the dehydration rate η3 after soaking for 30 days;

[0117] pass (Formula IV) The volume shrinkage rate η4 after soaking for 30 days was calculated, and the specific results are shown in Table 6.

[0118] (6) Dehydration rate and volume shrinkage rate of the gel prepared by high-temperature and high-salt soaking for 90 days for elastic gel particles

[0119] First, the surface of the gels prepared in Examples 1 to 6 and Comparative Examples 1 to 3 was uniformly sprayed with a 1 wt% NaOH aqueous solution to adjust the pH to neutral. Then, the gels were cut into cubes with an edge length of 5 cm, and their initial mass was recorded as m0 and their initial volume as V0 (i.e., 125 cm³). 3 Place the gel blocks into beakers containing saline solution with a mineralization of 214812.46 mg / L, ensuring the gel blocks are completely submerged. After placing the beakers in a constant temperature oven at 130℃ for 90 days, remove the soaked gel blocks from each beaker, rinse them three times with deionized water, wipe the surface of the rinsed gel blocks with absorbent paper, and cool them to room temperature (i.e., 25℃). Then weigh and measure their volume, and record the mass m2 and volume V2 of the gel blocks after water loss.

[0120] pass (Formula V) calculates the dehydration rate η5 after soaking for 90 days;

[0121] pass (Formula VI) calculates the volume shrinkage rate η6 after soaking for 90 days. The specific results are shown in Table 6.

[0122] Table 6. Dehydration rate and volume shrinkage rate of the gel after 30 and 90 days of high-temperature and high-salt immersion in the gel for preparing elastic gel particles.

[0123]

[0124] The data in Table 6 show that the gel blocks of the elastic gel particles prepared in Examples 1 to 6, after soaking in brine at 130°C and 214812.46 mg / L for 30 days, had a dehydration rate of 10% to 24.5% and a volume shrinkage rate of 20% to 33%; after soaking for 90 days, the dehydration rate was 15% to 30% and the volume shrinkage rate was 29% to 45%. This demonstrates that the gel blocks of the elastic gel particles prepared in Examples 1 to 6 can maintain their stability for a long time under high temperature and high mineralization conditions of 130°C and 214812.46 mg / L, ensuring good and stable blockage regulation effect under high temperature and high salt environment. The gel blocks prepared from the elastic gel particles in Comparative Examples 1 and 2 were soaked in brine at 130°C and 214812.46 mg / L for 30 days, with a dehydration rate of 36% to 45% and a volume shrinkage rate of 42.5% to 50%; after soaking for 90 days, the dehydration rate was 55% to 60% and the volume shrinkage rate was 60% to 65%. The stability under high temperature and high mineralization was poor. The dehydration rate and volume shrinkage rate after soaking for 30 days and 90 days were higher than those of the gel blocks prepared from the elastic gel particles in Examples 1 to 6. The gel block of elastic gel particles prepared in Comparative Example 3 showed slightly better stability than Comparative Example 1 and Comparative Example 2 at a high temperature and high mineralization of 130℃ and 214812.46 mg / L. However, its dehydration rate and volume shrinkage rate after soaking for 90 days were 35% and 50% respectively, which were higher than those of the gel blocks of elastic gel particles prepared in Examples 1 to 6. Therefore, the gel block of elastic gel particles prepared in Comparative Example 3 showed worse stability than the gel blocks of elastic gel particles prepared in Examples 1 to 6 at a high temperature and high mineralization of 130℃ and 214812.46 mg / L.

[0125] 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 method for preparing elastic gel particles, comprising the following steps: 1) Sodium-based bentonite and water are mixed to obtain the first dispersion; 2) Mix the crosslinking agent, sulfonated phenolic resin, and the first dispersion to obtain the second dispersion; 3) Mix polyvinyl alcohol and the second dispersion to obtain a third dispersion; 4) Mix the acid catalyst and the third dispersion, react to obtain a gel, granulate to obtain the elastic gel particles; The elastic gel particles are 100% by weight, the amount of sodium bentonite is 2wt% to 6wt%, the amount of sulfonated phenolic resin is 1wt% to 3wt%, the amount of crosslinking agent is 0.3wt% to 0.7wt%, the amount of polyvinyl alcohol is 4wt% to 10wt%, the amount of acid catalyst is 0.5wt% to 1.5wt%, and the amount of water is 78.8wt% to 92.2wt%. In step 4), the reaction conditions are to stand at 22°C to 25°C for 4 to 8 hours.

2. The method according to claim 1, characterized in that, The crosslinking agent is selected from aldehyde crosslinking agents and / or hexamethylenetetramine; and / or The acid catalyst is an inorganic acid and / or an organic acid; and / or The water has a mineralization of less than 1000 mg / L; The aldehyde crosslinking agent is selected from at least one of formaldehyde, paraformaldehyde, glyoxal, glutaraldehyde, and terephthalaldehyde; and / or The organic acids include haloacetic acids and / or alkylbenzene sulfonic acids; The inorganic acid is hydrochloric acid and / or sulfuric acid; and / or the haloacetic acid is chloroacetic acid; and / or the alkylbenzene sulfonic acid is p-toluenesulfonic acid.

3. The method according to claim 1 or 2, characterized in that, The sulfonated phenolic resin has a sulfur content of 8 wt% to 10 wt%; and / or a solid content of not less than 90 wt%; and / or The degree of alcoholysis of the polyvinyl alcohol is 87% to 89%; and / or the molecular weight is 100,000 to 1,200,000.

4. The method according to claim 1 or 2, characterized in that, In step 4), based on the visual code evaluation method, the strength of the gel reaches level I; and / or During the granulation process, an alkaline solution is sprayed onto the surface of the elastic gel particles to adjust the pH of the surface of the elastic gel particles to neutral. The alkaline solution is selected from at least one of sodium hydroxide solution, sodium carbonate solution, triethanolamine and sodium bicarbonate solution.

5. An elastic gel particle prepared by the method according to any one of claims 1 to 4.

6. The elastic gel particles according to claim 5, characterized in that, The elastic gel particles have a particle size of 1×10⁻⁶. 1 nm to 3×10 6 nm.

7. The application of the elastic gel particles prepared by the method according to any one of claims 1 to 4, or the elastic gel particles according to claim 5 or 6, in high-temperature, high-salinity fractured-vuggy reservoirs.

8. The application according to claim 7, characterized in that, The application is the use of the elastic gel particles in the flow channel adjustment of high-temperature, high-salinity fractured-vuggy reservoirs.

9. The application according to claim 7 or 8, characterized in that, The high temperature is not lower than 130°C; and / or The term "high salt" refers to a mineralization degree of not less than 210,000 mg / L.

Images