Liquid silicone rubber composition and application thereof

Abstract

The present invention provides a liquid silicone rubber composition and its application. The liquid silicone rubber composition mainly comprises silicone rubber, a crosslinking agent, a catalyst, and a diluent, and secondarily comprises a filler. The catalyst is a weak acid, which synergistically enhances the effect with the crosslinking agent and helps to slow the curing speed of the liquid silicone rubber. The liquid silicone rubber composition has good fluidity, is not diluted by water, and has a density of 1.07 to 1.12 g / cm 3 Adjustable, salt-resistant and high-temperature resistant, it can slowly solidify in a high-temperature and high-mineralization environment: after the liquid silicone rubber composition is mixed with formation water with a mineralization of 220,000 mg / L, it is placed in a 150°C oven for 8 to 20 hours, and its strength reaches F grade. It is suitable as a plugging agent for use in profile control and water plugging operations in high-temperature and high-salt rock fracture-cavern oil reservoirs.

Description

Technical Field

[0001] The invention belongs to the technical field of oil reservoir profile control and water plugging, and in particular relates to a liquid silicone rubber composition and application thereof. Background Art

[0002] The Tahe Oilfield is a high-temperature, ultra-high-salt rock fracture-cavity reservoir with a burial depth exceeding 5000m, a temperature exceeding 125°C, and a mineralization exceeding 22×10 4 mg / L. Reservoirs are primarily composed of large-scale caves and fractures ranging from several meters to tens of meters, creating a large volume of water in the reservoir space. During development, injected water and bottom water rapidly penetrate fractures, significantly increasing the water content of the well and leading to a rapid decline in oil production. A high-density delayed-curing system that is both resistant to ultra-high temperatures and dilution is urgently needed. Conventional polymer gels have poor dilution resistance and are easily hydrolyzed at high temperatures, resulting in poor plugging effectiveness. Granular plugging agents primarily consist of particles such as fly ash, cement, and rubber. These are formulated into a suspension and injected into the formation, bridging pore throats to achieve plugging. Granular plugging agents offer advantages such as low cost and high plugging strength. However, these plugging agents have difficulty bridging large fracture channels in fracture-vuggy reservoirs, making remote plugging difficult. Liquid silicone rubber, in addition to its outstanding high and low temperature resistance, resilience, and hydrophobicity, also possesses a certain degree of fluidity, making it a promising plugging agent. However, existing liquid silicone rubber mainly comes in two types: room temperature vulcanizing type and high temperature curing type. The former cures and forms in a few hours or even days at room temperature, while the latter cures and forms in a few minutes at high temperature. The extremely fast curing time at high temperature makes it impossible for it to penetrate deep into high-temperature and ultra-high salt rock fracture-cavity reservoirs to seal cracks when used as a plugging agent, and cannot meet the requirements of profile control and water blocking in high-temperature and ultra-high salt rock fracture-cavity reservoirs. Summary of the Invention

[0003] In view of the problem that liquid silicone rubber in the prior art forms too quickly at high temperatures and cannot penetrate deep into high-temperature and ultra-high salt rock fracture-cavity oil reservoirs to effectively seal cracks, the purpose of the present invention is to provide a liquid silicone rubber plugging agent that delays curing at a high temperature of not less than 130°C and a high mineralization of not less than 220,000 mg / L.

[0004] To achieve the above object, the present invention provides a liquid silicone rubber composition comprising silicone rubber, a crosslinking agent, a catalyst and a diluent.

[0005] According to a specific embodiment of the present invention, the liquid silicone rubber composition further includes a filler.

[0006] According to a specific embodiment of the present invention, the total mass of the liquid silicone rubber composition is taken as 100 parts by mass, and the liquid silicone rubber composition includes 20 to 50 parts by mass of silicone rubber, 1 to 10 parts by mass of a crosslinking agent, 0 to 30 parts by mass of a filler, 0.1 to 0.5 parts by mass of a catalyst, and the balance of a diluent;

[0007] Preferably, the liquid silicone rubber composition includes 20 to 50 parts by mass of the silicone rubber, 3 to 8 parts by mass of the crosslinking agent, 10 to 20 parts by mass of the filler, 0.2 to 0.4 parts by mass of the catalyst, and 34.8 to 59.7 parts by mass of the diluent.

[0008] According to a specific embodiment of the present invention, the crosslinking agent is selected from at least one of silicate compounds, alkoxysilane compounds, alkylalkoxysilane compounds, alkenylalkoxysilane compounds, phenylalkoxysilane compounds, halogenated alkylalkoxysilane compounds, isocyanate-containing alkoxysilane compounds and polyalkoxypolysiloxane compounds.

[0009] According to a specific embodiment of the present invention, the catalyst is a weak acid.

[0010] According to a specific embodiment of the present invention, the crosslinking agent is selected from at least one of tetraethyl silicate, tetramethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, trimethoxysilane, octyltrimethoxysilane, chloropropyltriethoxysilane, phenyltriethoxysilane, triethoxysilane, vinyltriethoxysilane, octyltriethoxysilane, vinyltriisopropoxysilane, tetraisopropyl orthosilicate, isocyanatepropyltriethoxysilane, crosslinking agent MOSO and crosslinking agent EOSO;

[0011] Preferably, the crosslinking agent is selected from at least one of tetraethyl silicate, phenyltrimethoxysilane, crosslinking agent MOSO and crosslinking agent EOSO.

[0012] The crosslinking agent MOSO described in the present invention is polymethoxypolysiloxane.

[0013] The crosslinking agent EOSO described in the present invention is polyethoxypolysiloxane.

[0014] According to a specific embodiment of the present invention, the catalyst is selected from at least one of acetic acid, caproic acid, lauric acid, stearic acid, oleic acid and adipic acid;

[0015] Preferably, the catalyst is selected from at least one of adipic acid, stearic acid and lauric acid;

[0016] and / or

[0017] The silicone rubber is 107 silicone rubber; and / or

[0018] The diluent is dimethyl silicone oil;

[0019] Preferably, the diluent is recycled dimethyl silicone oil;

[0020] Preferably, the viscosity of the 107 silicone rubber at 25° C. is 500 to 5000 mPa.s; and / or

[0021] The viscosity of the dimethyl silicone oil at 25° C. is 50 to 500 mPa.s;

[0022] Preferably, the viscosity of the 107 silicone rubber at 25° C. is 800 to 4500 mPa.s; and / or

[0023] The viscosity of the dimethyl silicone oil at 25° C. is 100 to 400 mPa.s.

[0024] The 107 silicone rubber described in the present invention is polydimethylsiloxane terminated with silanol groups.

[0025] According to a specific embodiment of the present invention, the filler is selected from at least one of calcium carbonate, fly ash, alumina, silica powder, talc, barium sulfate and zinc oxide; and / or

[0026] The average particle size of the filler is 1000 mesh to 3000 mesh;

[0027] Preferably, the filler is selected from at least one of calcium carbonate, barium sulfate, talc and silica powder; and / or

[0028] The average particle size of the filler is 1200 mesh to 3000 mesh.

[0029] According to a specific embodiment of the present invention, the cross-linking agent MOSO or the cross-linking agent EOSO is prepared by the following method:

[0030] A first low-hydrogen silicone oil and vinyltrimethoxysilane are reacted with each other under the action of a first platinum catalyst to obtain the crosslinking agent MOSO; or

[0031] The second low-hydrogen silicone oil and vinyltriethoxysilane are subjected to a second reaction under the action of a second platinum catalyst to obtain the crosslinking agent EOSO.

[0032] According to a specific embodiment of the present invention, after the first reaction, unreacted vinyltrimethoxysilane is removed in vacuo to obtain the crosslinking agent MOSO; or

[0033] After the second reaction, unreacted vinyltriethoxysilane is removed in vacuo to obtain the crosslinking agent EOSO.

[0034] According to a specific embodiment of the present invention, the amount of the first low-hydrogen silicone oil is 100 parts by mass, the amount of the vinyltrimethoxysilane is 5 to 30 parts by mass, and the amount of the first platinum catalyst is 0.2 to 0.5 parts by mass; or

[0035] The amount of the second low-hydrogen silicone oil is 100 parts by mass, the amount of the vinyltriethoxysilane is 5 to 30 parts by mass, and the amount of the second platinum catalyst is 0.2 to 0.5 parts by mass;

[0036] Preferably, the amount of the first low-hydrogen silicone oil is 100 parts by mass, the amount of the vinyltrimethoxysilane is 15 to 20 parts by mass, and the amount of the first platinum catalyst is 0.2 to 0.3 parts by mass;

[0037] or

[0038] The amount of the second low-hydrogen silicone oil is 100 parts by mass, the amount of the vinyltriethoxysilane is 15 to 20 parts by mass, and the amount of the second platinum catalyst is 0.2 to 0.3 parts by mass;

[0039] Preferably, the amount of the first low-hydrogen silicone oil is 100 parts by mass, the amount of the vinyltrimethoxysilane is 20 parts by mass, and the amount of the first platinum catalyst is 0.2 parts by mass; or

[0040] The amount of the second low-hydrogen silicone oil used is 100 parts by mass, the amount of the vinyltriethoxysilane used is 15 parts by mass, and the amount of the second platinum catalyst used is 0.3 parts by mass.

[0041] According to a specific embodiment of the present invention, the hydrogen content of the first low-hydrogen silicone oil and the second low-hydrogen silicone oil is independently 0.1wt% to 0.3wt%; and / or the viscosity is independently 25mPa.s to 50mPa.s; and / or

[0042] The first platinum catalyst and the second platinum catalyst are independently a complex of zero-valent platinum and vinyl silane; and / or

[0043] The effective platinum content of the first platinum catalyst and the second platinum catalyst is independently 4000 ppm;

[0044] Preferably, the hydrogen content of the first low-hydrogen silicone oil and the second hydrogen-containing silicone oil is independently 0.18 wt% to 0.2 wt%; and / or the viscosity is independently 30 mPa.s to 40 mPa.s;

[0045] Preferably, the hydrogen content of the first low-hydrogen silicone oil is 0.18 wt%; and / or the viscosity is 30 mPa.s; or

[0046] The second low-hydrogen silicone oil has a hydrogen content of 0.2 wt% and / or a viscosity of 40 mPa.s.

[0047] According to one embodiment of the present invention, the conditions of the first reaction and the second reaction are independently stirring at 100° C. to 130° C. for 1 h to 5 h;

[0048] Preferably, the conditions of the first reaction and the second reaction are independently stirring at 100° C. to 120° C. for 1 to 2 hours;

[0049] Preferably, the first reaction is carried out under stirring at 100° C. for 2 h; or

[0050] The second reaction was carried out under stirring at 120° C. for 1 h.

[0051] According to a specific embodiment of the present invention, the viscosity of the liquid silicone rubber composition after mixing all the components at room temperature is 500mPa.s to 5000mPa.s; and / or the density is 1.0g / cm 3 to 1.3g / cm 3 ;

[0052] Preferably, the viscosity of the liquid silicone rubber composition after mixing all the components at room temperature is 800mPa.s to 3100mPa.s; and / or the density is 1.07g / cm 3 to 1.12g / cm 3 .

[0053] According to a specific embodiment of the present invention, the curing temperature of the liquid silicone rubber composition is 130° C. to 160° C.; and / or the curing time is 8 hours to 24 hours;

[0054] Preferably, the liquid silicone rubber composition is cured at 150° C. for 8 to 20 hours.

[0055] The term "curing" as used in the present invention means that the gel strength of the liquid silicone rubber composition reaches Class F according to the visual code evaluation method.

[0056] Application of the liquid silicone rubber composition according to the present invention in oil reservoir profile control and water plugging, particularly application as a plugging agent in high-temperature and high-salt rock fracture-cavity oil reservoir profile control and water plugging;

[0057] Preferably, the high temperature is not less than 130° C.; and / or the high salt has a mineralization of not less than 220,000 mg / L.

[0058] Beneficial effects of the present invention:

[0059] In order to solve the problem that the liquid silicone rubber in the prior art is formed too quickly at high temperature and cannot penetrate deep into the high-temperature and ultra-high salt rock fracture-cavity oil reservoir to effectively seal the cracks, the present invention provides a liquid silicone rubber composition. The liquid silicone rubber composition mainly includes silicone rubber, a cross-linking agent, a catalyst and a diluent, and secondly also includes a filler. Among them, the catalyst is a weak acid, which synergistically enhances the effect with the cross-linking agent to help slow down the curing speed of the liquid silicone rubber. The liquid silicone rubber composition has good fluidity, will not be diluted when exposed to water, and has a density of 1.07 to 1.12 g / cm 3 Adjustable, salt-resistant and high-temperature resistant, it can slowly solidify in a high-temperature and high-mineralization environment: after the liquid silicone rubber composition is mixed with formation water with a mineralization of 220,000 mg / L, it is placed in a 150°C oven for 8 to 20 hours, and its strength reaches F grade. It is suitable for use as a plugging agent in profile control and water plugging operations in high-temperature and ultra-high-salt oil reservoirs such as the Tahe Oilfield, and can effectively seal cracks deep in the oil reservoir. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 This is the H-NMR spectrum of the cross-linking agent MOSO prepared in Example 3.

[0061] Figure 2 This is the infrared spectrum of the cross-linking agent MOSO prepared in Example 3.

[0062] Figure 3 This is the H-NMR spectrum of the cross-linking agent EOSO prepared in Example 4.

[0063] Figure 4 This is the infrared spectrum of the cross-linking agent EOSO prepared in Example 4.

[0064] Figure 5 This is the H-NMR spectrum of the 107 silicone rubber used in any one of Examples 1 to 4 and Comparative Examples 1 to 3.

[0065] Figure 6 Surface attenuated total reflection infrared spectrum of the liquid silicone rubber composition prepared in Example 1 after gelation. DETAILED DESCRIPTION

[0066] The present invention will be further described below with reference to examples. However, the examples are merely illustrative and do not limit the present invention in any way.

[0067] The platinum catalyst used in Examples 3 and 4 has a CAS number of 68478-92-2 and an effective platinum content of 4000 ppm, and was purchased from Shanghai Myrrel Biochemical Technology Co., Ltd.

[0068] Example 1

[0069] Preparation of liquid silicone rubber composition:

[0070] The liquid silicone rubber composition in this embodiment includes 40g of 107 silicone rubber (viscosity of 1000mPa.s), 3g of tetraethyl silicate, 20g of calcium carbonate particles (average particle size of 3000 mesh), 0.2g of adipic acid, and 37.8g of recycled dimethyl silicone oil (viscosity of 100mPa.s);

[0071] All components of the liquid silicone rubber composition of this embodiment were mixed and dispersed in a high-speed disperser for 1 hour to obtain a liquid silicone rubber having a viscosity of 800 mPa.s and a density of 1.12 g / cm 3 A liquid silicone rubber composition, a liquid silicone rubber plugging agent.

[0072] Example 2

[0073] Preparation of liquid silicone rubber composition:

[0074] The liquid silicone rubber composition in this embodiment includes 50g of 107 silicone rubber (viscosity of 2000mPa.s), 5g of phenyltrimethoxysilane, 10g of barium sulfate particles (average particle size of 2000 mesh), 0.2g of stearic acid, and 34.8g of recycled dimethyl silicone oil (viscosity of 200mPa.s);

[0075] All components of the liquid silicone rubber composition of this embodiment were mixed uniformly using a three-roll mill to obtain a liquid silicone rubber having a viscosity of 1600 mPa.s and a density of 1.09 g / cm 3 A liquid silicone rubber composition, a liquid silicone rubber plugging agent.

[0076] Example 3

[0077] Preparation of crosslinker MOSO:

[0078] 100 g of low-hydrogen silicone oil (hydrogen content 0.18%, viscosity 30 mPa·s), 20 g of vinyltrimethoxysilane, and 0.2 g of platinum catalyst (effective platinum content 4000 ppm) were mixed uniformly, stirred and reacted at 100° C. for 2 h, and the unreacted vinyltrimethoxysilane was removed in vacuo to obtain the crosslinking agent MOSO;

[0079] Preparation of liquid silicone rubber composition:

[0080] The liquid silicone rubber composition in this embodiment includes 30g of 107 silicone rubber (viscosity of 800mPa.s), 8g of crosslinking agent MOSO, 20g of talc (average particle size of 1200 mesh), 0.4g of stearic acid, and 41.2g of recycled dimethyl silicone oil (viscosity of 400mPa.s);

[0081] All components of the liquid silicone rubber composition of this embodiment were mixed and dispersed in a high-speed disperser for 1 hour to obtain a liquid silicone rubber having a viscosity of 2500 mPa.s and a density of 1.10 g / cm 3 A liquid silicone rubber composition, a liquid silicone rubber plugging agent.

[0082] Example 4

[0083] Preparation of crosslinker EOSO:

[0084] 100 g of low-hydrogen silicone oil (hydrogen content 0.20%, viscosity 40 mPa·s), 15 g of vinyltriethoxysilane and 0.3 g of platinum catalyst (effective platinum content 4000 ppm) were mixed evenly, stirred and reacted at 120° C. for 1 h, and the unreacted vinyltriethoxysilane was removed in vacuo to obtain the crosslinking agent EOSO;

[0085] Preparation of liquid silicone rubber composition:

[0086] The liquid silicone rubber composition in this embodiment includes 20g of 107 silicone rubber (viscosity of 4500mPa.s), 5g of crosslinking agent EOSO, 15g of silicon powder (average particle size of 2000 mesh), 0.3g of lauric acid, and 59.7g of recycled dimethyl silicone oil (viscosity of 100mPa.s);

[0087] All components of the liquid silicone rubber composition of this embodiment were mixed and dispersed in a high-speed disperser for 1 hour to obtain a liquid silicone rubber having a viscosity of 3100 mPa.s and a density of 1.07 g / cm 3 A liquid silicone rubber composition, a liquid silicone rubber plugging agent.

[0088] Comparative Example 1

[0089] The tetraethyl silicate in Example 1 was replaced with an equal mass of vinyltributylon oxime silane, a crosslinking agent commonly used for room temperature vulcanized silicone rubber, and the rest was the same as in Example 1 to obtain a liquid silicone rubber composition, a liquid silicone rubber plugging agent.

[0090] Comparative Example 2

[0091] The adipic acid in Example 1 was replaced with an equal mass of dibutyltin dilaurate, a catalyst commonly used in room temperature vulcanized silicone rubber, and the rest was the same as in Example 1 to obtain a liquid silicone rubber composition, a liquid silicone rubber plugging agent.

[0092] Comparative Example 3

[0093] The tetraethyl silicate in Example 1 was replaced by an equal mass of methyltributylidene oxime silane, and the adipic acid was replaced by an equal mass of dibutyltin dilaurate. Other conditions were the same as in Example 1 to obtain a liquid silicone rubber composition, a liquid silicone rubber plugging agent.

[0094] Structural characterization of crosslinker MOSO, crosslinker EOSO, 107 silicone rubber and liquid silicone rubber composition after gelation

[0095] (1) Structural characterization of crosslinker MOSO

[0096] Figure 1 This is the H NMR spectrum of the cross-linker MOSO prepared in Example 3. The solvent is deuterated chloroform. A signal of hydrogen on the methoxy group appears at a chemical shift of 3.5 ppm, a signal of the methylene group connected to silicon appears at a chemical shift of 0.5 ppm, and a peak appearing at 0 to 0.3 ppm is attributed to the signal of methyl hydrogen.

[0097] Figure 2 This is the infrared spectrum of the cross-linking agent MOSO prepared in Example 3. In the figure, 2959 and 2837 cm -1 The methoxymethyl stretching vibration peak appeared at 2901 cm -1 The stretching vibration peak of silyl methyl group appeared at 2152 cm -1 The absorption peak at 1409cm belongs to the vibration absorption peak of residual silicon hydrogen. -1 The bending vibration absorption peak of methylene appeared at 1258 cm -1 The bending vibration absorption peak of methyl group appeared at 1000 to 1200 cm -1 The vibration absorption peak of silicon-carbon bond appears at 797 cm -1 The vibration absorption peak of silicon-oxygen bond appears at

[0098] pass Figure 1 The H NMR spectrum and Figure 2 The infrared spectrum shown shows that the cross-linking agent MOSO with the target structure, i.e., polymethoxy polysiloxane, was prepared in Example 3.

[0099] (2) Structural characterization of crosslinker EOSO

[0100] Figure 3 This is the H NMR spectrum of the cross-linker EOSO prepared in Example 4. The solvent is deuterated chloroform. A signal of -CH2- hydrogen on the ethoxy group appears at a chemical shift of 3.75 ppm, a signal of -CH3 hydrogen on the ethoxy group appears at a chemical shift of 1.14, a signal of methylene connected to silicon appears at a chemical shift of 0.5 ppm, a peak appearing at 0 to 0.3 ppm is attributed to the signal of methyl hydrogen, and a peak at a chemical shift of 4.6 ppm is attributed to the signal of residual silicon hydrogen.

[0101] Figure 4 This is the infrared spectrum of the cross-linking agent EOSO prepared in Example 4. -1 The ethoxymethyl stretching vibration peak appeared at 2927 cm -1The ethoxymethylene stretching vibration peak appeared at 2904 cm -1 The stretching vibration peak of silyl methyl group appeared at 2152 cm -1 The absorption peak at 1409cm belongs to the vibration absorption peak of residual silicon hydrogen. -1 The bending vibration absorption peak of methylene appeared at 1261 cm -1 The bending vibration absorption peak of methyl group appeared at 1000 to 1200 cm -1 The vibration absorption peak of silicon-carbon bond appears at 793cm -1 The vibration absorption peak of silicon-oxygen bond appears at

[0102] pass Figure 3 The H NMR spectrum and Figure 4 The infrared spectrum shown in FIG. 4 shows that the cross-linking agent EOSO, i.e., polyethoxypolysiloxane, with the target structure was prepared in Example 4.

[0103] (3) Structural characterization of 107 silicone rubber and its liquid silicone rubber composition after gelation

[0104] Figure 5 The H NMR spectrum of the 107 silicone rubber used in any one of Examples 1 to 4 of the present invention and Comparative Examples 1 to 3 shows a methyl signal at a chemical shift of 0 to 0.2 ppm, indicating that any one of Examples 1 to 4 and Comparative Examples 1 to 3 of the present invention is indeed 107 silicone rubber.

[0105] Figure 6 This is the surface attenuated total reflection infrared spectrum of the liquid silicone rubber composition (or liquid silicone rubber plugging agent) prepared in Example 1 after gelation. It can be determined that the material is based on polydimethylsiloxane. Since the amount of cross-linking agent and catalyst is too small, they cannot be reflected in the spectrum.

[0106] Evaluation of liquid silicone rubber compositions

[0107] The gelation state of the liquid silicone rubber compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 under high temperature and high salt conditions (i.e., 150° C. and a salinity of 220,000 mg / L) was observed, and their delayed curing performance at high temperature was evaluated. The specific steps were as follows:

[0108] i. Weigh 100 g of each of the liquid silicone rubber compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3, place them in ampoules together with 50 g of formation water having a salinity of 220,000 mg / L, seal the ampoules, and place them in an oven at 150° C. to begin the experiment. Within 2 hours after the start of the experiment, observe and record the gelation state of the liquid silicone rubber composition every 0.1 hour. Starting after the experiment reaches 2 hours, observe and record the gelation state of the liquid silicone rubber composition every 2 hours.

[0109] ii. According to the visual code evaluation method of Sydansk et al., which classifies the gel strength of the plugging agent into 10 levels based on visual inspection results, the time when the liquid silicone rubber compositions prepared in Examples 1 to 4 and Comparative Examples 1 to 3 reached Grade F was determined in combination with Table 1. The specific results are shown in Table 2.

[0110] Table 1. Gel Strength Code Standards

[0111]

[0112] Table 2. Time for liquid silicone rubber composition to reach F grade

[0113] Serial number Time to reach F level / h Example 1 20 Example 2 14 Example 3 8 Example 4 12 Comparative Example 1 2 Comparative Example 2 0.5 Comparative Example 3 0.2

[0114] As can be seen from Table 2, the liquid silicone rubber compositions prepared in Examples 1 to 4 take 8 to 20 hours to reach Class F gel strength (specifically, the high deformation non-flowing gel in Table 1) at a high temperature of 150°C, and the gel time is long enough. Compared with Example 1, Comparative Example 1 replaces the crosslinking agent tetraethyl silicate with an equal mass of vinyl trisbutyl ketoxime silane, that is, uses a crosslinking agent commonly used for room temperature vulcanized silicone rubber outside the scope of the present invention. The curing time of the liquid silicone rubber composition prepared therefrom is shortened by 90%, specifically 2 hours, which cannot meet the water plugging operation that requires delayed curing under high temperature conditions; Compared with Example 1, Comparative Example 2 replaces adipic acid with an equal mass of dibutyltin dilaurate, that is, uses a catalyst commonly used for room temperature vulcanized silicone rubber outside the scope of the present invention. The curing time of the liquid silicone rubber composition prepared therefrom is shortened by 90%, specifically 2 hours. Compared with Example 1, Comparative Example 3 replaced the crosslinker tetraethyl silicate with an equal mass of methyltributylanoximesilane and the catalyst adipic acid with an equal mass of dibutyltin dilaurate. The replacement crosslinker and catalyst were both outside the scope of the present invention. The resulting liquid silicone rubber composition had a very short curing time of only 0.2 h at 150°C, a 99% reduction in curing time compared to Example 1. It is also unsuitable for water plugging operations requiring delayed curing under high temperature conditions. Therefore, the liquid silicone rubber compositions prepared in Comparative Examples 1 to 3 cannot be used for profile control and water plugging operations in high-temperature, ultra-high-salinity reservoirs such as the Tahe Oilfield due to their excessively fast curing speed at high temperatures. The above experimental results can prove that the catalyst and the cross-linking agent in the liquid silicone rubber composition provided by the present invention have a synergistic effect in delaying the curing speed of the liquid silicone rubber, so that the liquid silicone rubber composition can slowly cure under high temperature and ultra-high salinity conditions, with a curing time of 8 to 20 hours. It is suitable for use as a plugging agent in profile control and water plugging operations in high-temperature and ultra-high salinity oil reservoirs such as the Tahe Oilfield, and can effectively seal cracks deep in the oil reservoir.

[0115] Although the present invention has been described with reference to specific embodiments, those skilled in the art will appreciate that various modifications may be made without departing from the true spirit and scope of the invention. Furthermore, the subject matter, spirit, and scope of the invention may be modified in various ways to adapt to specific circumstances, materials, combinations of materials, and methods. All such modifications are intended to be within the scope of the claims.

Claims

1. A liquid silicone rubber composition comprising silicone rubber, a crosslinking agent, a catalyst and a diluent; The silicone rubber is 107 silicone rubber; The crosslinking agent is selected from at least one of tetraethyl silicate, tetramethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, phenyltrimethoxysilane, trimethoxysilane, octyltrimethoxysilane, chloropropyltriethoxysilane, phenyltriethoxysilane, triethoxysilane, vinyltriethoxysilane, octyltriethoxysilane, vinyltriisopropoxysilane, tetraisopropyl orthosilicate, isocyanatepropyltriethoxysilane, crosslinking agent MOSO and crosslinking agent EOSO; the crosslinking agent MOSO is a polymethoxy polysiloxane; the crosslinking agent EOSO is a polyethoxy polysiloxane; The catalyst is selected from at least one of acetic acid, caproic acid, lauric acid, stearic acid, oleic acid and adipic acid; The diluent is dimethyl silicone oil; The viscosity of the 107 silicone rubber at 25° C. is 500 to 5000 mPa.s; The viscosity of the dimethyl silicone oil at 25° C. is 50 to 500 mPa.s.

2. The liquid silicone rubber composition according to claim 1, characterized in that The liquid silicone rubber composition further includes a filler.

3. The liquid silicone rubber composition according to claim 2, wherein Taking the total mass of the liquid silicone rubber composition as 100 parts by mass, the liquid silicone rubber composition includes 20 to 50 parts by mass of silicone rubber, 1 to 10 parts by mass of a crosslinking agent, 0 to 30 parts by mass of a filler, 0.1 to 0.5 parts by mass of a catalyst, and the balance being a diluent.

4. The liquid silicone rubber composition according to claim 2, characterized in that The filler is selected from at least one of calcium carbonate, fly ash, alumina, silica powder, talc, barium sulfate and zinc oxide; and / or The average particle size of the filler is 1000 mesh to 3000 mesh.

5. The liquid silicone rubber composition according to any one of claims 1 to 4, characterized in that The liquid silicone rubber composition is cured at a temperature of 130° C. to 160° C. and / or for a curing time of 8 hours to 24 hours.

6. Use of the liquid silicone rubber composition according to any one of claims 1 to 5 in oil reservoir profile control and water plugging, that is, use as a plugging agent in high-temperature, high-salt rock fracture-cavity oil reservoir profile control and water plugging; The high temperature is not less than 130° C.; and / or the high salt has a mineralization degree not less than 220,000 mg / L.

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