Rubber-carrying particle reinforced gel foam system as well as preparation method and application thereof

Abstract

The invention provides a rubber-carrying particle reinforced gel foam system as well as a preparation method and application thereof, and relates to the field of oil gas chemistry. The gel foam system comprises the following components: a tea saponin surfactant, polyacrylamide, a phenolic aldehyde cross-linking agent, rubber particles and water, the polyacrylamide is nonionic polyacrylamide, and the molecular weight is 5-15 million; according to the preparation method, all the components are well mixed and compounded, the prepared rubber-carrying particle reinforced gel foam system is better in foaming performance, higher in stability and long in drainage half-life period through the preparation method with the specific rotating speed and the specific feeding sequence, and the rubber-carrying particle reinforced gel foam system can affect farther and deeper cracks or karst caves for profile control and displacement in high-temperature and high-salt fracture-vuggy carbonate rock oil reservoir exploitation.

Description

Technical Field

[0001] The invention belongs to the field of oil and gas chemistry, and particularly relates to a rubber particle-carrying reinforced gel foam system, a preparation method and an application thereof. Background Art

[0002] Carbonate oil and gas reservoirs occupy a vital position in the petroleum industry. Fracture-vuggy carbonate reservoirs underwent multiple phases of tectonic movement during their formation, and reservoir development characteristics vary significantly under different karst geological conditions. Large caves and dissolution pores are the primary reservoir spaces, and fractures are the primary flow pathways. Due to the unique reservoir characteristics of fracture-vuggy reservoirs, depletion-based production is generally employed in the early stages of development, while water injection or gas injection is primarily used in the middle and late stages to enhance oil recovery. However, due to the low viscosity of the gas and the high gas-oil mobility ratio, pure gas drive is prone to viscous fingering, and is particularly prone to gas channeling. This results in low gas drive sweep efficiency, a small sweep range, and a limited increase in oil recovery.

[0003] As a compressible, non-Newtonian fluid, foam fluid, with its excellent properties, has achieved excellent field results in drilling, cementing, completion, reservoir protection, reservoir stimulation, and enhanced oil recovery, demonstrating great potential. Given the unique reservoir properties of unconventional oil reservoirs, the demand for high-performance materials is urgent, and foam fluids have attracted widespread attention due to their superior performance.

[0004] Chinese invention patent CN116064015B discloses a salt-sensitive self-crosslinking gel foam system, its preparation method, and its application. The system comprises the following raw materials: a hydroxysulfobetaine surfactant, a soluble monovalent metal cation sulfate, a soluble trivalent metal salt, sodium alginate, and deionized water. This system exhibits high resistance to mineralization and is suitable for fractured-cavity carbonate reservoirs in western China. However, the resulting gel foam requires a large amount of inorganic salts, which can corrode equipment and pipelines. Furthermore, upon injection into the formation, the salts decompose under high temperatures, preventing them from stably carrying the foam.

[0005] Chinese invention patent CN115058238A discloses a surface-modified nanoparticle high-temperature foam stabilizer, its preparation method, and its application. The stabilizer comprises the following raw materials: lithium magnesium silicate nanoparticles, a surface modifier, and an interfacial synergist. The system exhibits excellent temperature resistance and injectability. However, its flooding performance in fractured-vuggy carbonate reservoirs is poor.

[0006] Chinese invention patent CN115960598B discloses a micro-nano fly ash particle-enhanced foam system. This enhanced foam system can adjust the foam system viscosity by selecting the appropriate solid particle size range, polymer molecular weight, and polymer concentration based on the formation permeability, achieving self-suspension of the solid particles. This self-suspension allows solid particles of different sizes to exhibit different sedimentation and migration patterns, further enhancing their effectiveness within the formation. However, carbonate fracture-vuggy reservoirs primarily utilize large caves and erosion pores, with fractures as the primary flow channels. Injected micro-nano-scale fly ash particles have a weak sealing effect on the fractures. The presence of large-scale reservoirs weakens the formation's shearing effect on the foam, preventing effective foaming and secondary foaming within the formation. Furthermore, these micro-nano-scale fly ash particles cannot effectively regenerate the foam.

[0007] Zheng Jiazhen et al. (Performance and Mechanism of Modified Nanosilicon Particles Strengthening High-Temperature Foam, Materials Review, 2023.4) reported that the foam performance of sodium α-olefin sulfonate (AOS) was strengthened with modified nanosilicon particles (NP). The foam performance of the NP-strengthened foam system was evaluated by the Waring Blender method. The mechanism of NP-stabilized AOS foam and the plugging ability of NP-strengthened foam at high temperatures were studied. The results showed that 0.5% AOS foam strengthened with 2.0% NP had very stable foam performance. However, the cost of using nanoparticles in this invention is too high and is not suitable for actual application in oil fields.

[0008] Conventional foam systems are thermodynamically unstable, prone to defoaming, and have a short liquid separation half-life, making them unsuitable for high-temperature, high-salinity reservoirs. Therefore, developing a foam system that can withstand high temperatures and high salinity, generate large foam volumes, and maintain a long liquid separation half-life is crucial. Gel foams, due to their low cost, excellent injection performance, and ability to seal high-permeability formations, have been applied in oilfield operations, significantly improving crude oil recovery and generating significant economic benefits. Summary of the Invention

[0009] In response to the problems existing in the prior art, the present invention provides a rubber particle-carrying reinforced gel foam system, a preparation method thereof, and an application thereof. The gel foam system comprises components: a tea saponin surfactant, polyacrylamide, a phenolic crosslinking agent, rubber particles, and water. Nitrogen is introduced during the preparation process. The prepared gel foam system is low in cost, environmentally friendly, simple in preparation method, high in viscosity, and strong in stability. It can carry particles to seal cracks. The system is applied in oil and gas production to improve crude oil recovery.

[0010] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0011] Firstly, the present invention provides a rubber particle-carrying reinforced gel foam system, comprising components: tea saponin surfactant, polyacrylamide, phenolic crosslinking agent, rubber particles and water.

[0012] Preferably, the gel foam system comprises the following components, calculated in parts by weight: 0.4-0.8 parts of tea saponin surfactant, 0.3-0.6 parts of polyacrylamide, 0.3-0.6 parts of phenolic crosslinking agent, 1-12 parts of rubber particles and 85-115 parts of water.

[0013] Further preferably, the gel foam system comprises the following components, in parts by weight: 0.5-0.7 parts of tea saponin surfactant, 0.4-0.5 parts of polyacrylamide, 0.4-0.5 parts of phenolic crosslinking agent, 2-10 parts of rubber particles and 90-110 parts of water.

[0014] More preferably, the gel foam system comprises the following components in parts by weight: 0.5-0.7 parts of tea saponin surfactant, 0.4 parts of polyacrylamide, 0.5 parts of phenolic crosslinking agent, 2-10 parts of rubber particles and 100 parts of water.

[0015] Most preferably, the gel foam system comprises the following components, in parts by weight: 0.7 parts of tea saponin surfactant, 0.4 parts of polyacrylamide, 0.5 parts of phenolic crosslinking agent, 2 parts of rubber particles and 100 parts of water.

[0016] Preferably, the polyacrylamide is non-ionic polyacrylamide with a molecular weight of 5-15 million.

[0017] More preferably, the molecular weight of the polyacrylamide is 5-10 million.

[0018] More preferably, the molecular weight of the polyacrylamide is about 5 million.

[0019] Preferably, the phenolic crosslinking agent is at least one selected from phenolic resin, a mixture of hydroquinone and hexamethylenetetramine, and a mixture of phenol and formaldehyde.

[0020] More preferably, the phenolic crosslinking agent is a phenolic resin.

[0021] Preferably, the rubber particles have an average particle size of 20-40 mesh and a density of 1.9-2 g / cm 3 .

[0022] More preferably, the rubber particles have an average particle size of 30 mesh and a density of 1.94 g / cm 3 .

[0023] In the present invention, the tea saponin surfactant, also known as tea saponin, has multiple properties such as surface activity and biological activity; tea saponin is a sugar compound extracted from the seeds of the Theaceae plant, belongs to the saponin class, and is a natural non-ionic surfactant; tea saponin has good emulsification, dispersing, foaming and wetting functions.

[0024] In the present invention, the rubber particles are black and are mainly produced by processing waste rubber raw materials, including but not limited to waste rubber, rubber scraps, automobile floor mats, automobile tires, etc. The rubber particles are not shiny and are soft. When poured into water, they all float on the liquid surface.

[0025] Then, the present invention provides a method for preparing the gel foam system, comprising the steps of:

[0026] (1) mixing polyacrylamide with water and stirring to obtain a polymer solution;

[0027] (2) mixing and stirring the polymer solution of step (1) with rubber particles to obtain a polymer solution containing rubber particles;

[0028] (3) mixing and stirring the polymer solution containing rubber particles in step (2) with a tea saponin surfactant to obtain a polymer solution containing rubber particles and a surfactant;

[0029] (4) mixing and stirring the polymer solution containing rubber particles and surfactant in step (3) with a crosslinking agent to obtain a base liquid;

[0030] (5) The base liquid is stirred under nitrogen flow to obtain a gel foam system.

[0031] Preferably, in step (1), the stirring is performed at a speed of 1000-2000 rpm and the stirring time is 4-6 h.

[0032] Further preferably, in step (1), the stirring is performed at a speed of 1500 rpm and for a time of 5 h.

[0033] Preferably, in step (2), the stirring is carried out at a relatively high speed, the stirring speed is 1000-2000 rpm, and the stirring time is 20-40 min.

[0034] More preferably, the stirring speed is 1500 rpm and the stirring time is 30 min.

[0035] Preferably, in step (3), the stirring is carried out at a low speed, the stirring speed is 100-1000 rpm, and the stirring time is 5-20 min.

[0036] More preferably, the stirring speed is 500 rpm and the stirring time is 10 min.

[0037] Preferably, in step (4), the stirring is carried out by high-speed stirring, the stirring speed is 1000-2000 rpm, and the stirring time is 0.5-2 min.

[0038] More preferably, the stirring speed is 1500 rpm and the stirring time is 1 min.

[0039] Preferably, in step (5), the stirring is performed by high-speed stirring, the stirring speed is 7000-10000 rpm, and the stirring time is 2-5 min.

[0040] More preferably, the stirring speed is 8000 rpm and the stirring time is 3 min.

[0041] In the present invention, in step (2), since the rubber particles have a high density and are easy to settle, relatively high-speed stirring is adopted to prevent them from settling; in step (3), low-speed stirring is adopted to prevent foaming during stirring; in step (4), high-speed stirring is adopted to prevent the polymer and the cross-linking agent from cross-linking to form a gel; in step (5), nitrogen is introduced throughout the stirring process to prevent excessive viscosity from causing a decrease in foaming effect.

[0042] Finally, the present invention provides the application of the gel foam system in fracture-cavity carbonate reservoirs.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] 1. The components of the gel foam system of the present invention are well mixed and compounded. The prepared gel foam system carries rubber particles and is suitable for high-temperature and high-salt fracture-cavern oil reservoirs. It can withstand temperatures of 150°C and mineralization of 21×10 4 mg / L, calcium ion tolerance 1.4×10 4 mg / L, magnesium ion resistance 0.2×10 4 mg / L.

[0045] 2. The rubber particles in the gel foam system of the present invention are produced by processing various waste rubbers including waste rubber, rubber scraps, automobile pads, automobile tires and other waste rubber raw materials, which has certain environmental protection effects and waste utilization.

[0046] 3. The gel foam system of the present invention has the characteristic of "blocking large cracks but not small ones", so that the rubber particles carried by it can be transported with the gel foam to large cracks for blocking.

[0047] 4. In the gel foam system of the present invention, the accumulation and blocking of rubber particles can have an effect similar to that of sandstone formations, and can achieve shear foaming and secondary foaming effects on the foam that enters subsequently.

[0048] 5. Compared with ordinary foams, the gel foam system of the present invention has better foaming performance, stronger stability, a long liquid separation half-life, and can reach farther and deeper cracks or caves for flooding.

[0049] 6. The preparation method of the gel foam system of the present invention is simple and easy to operate. By gradually adding raw materials and controlling the rotation speed, the foaming performance of the gel foam system is better and more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 This is a schematic diagram of foaming using a simple tea saponin surfactant according to the present invention.

[0051] Figure 2 This is a diagram of the rubber particle-reinforced gel foam system prepared by the present invention. DETAILED DESCRIPTION

[0052] The following non-limiting examples can make those of ordinary skill in the art understand the present invention more comprehensively, but do not limit the present invention in any way. The following content is merely an exemplary description of the scope of protection of the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and they should also fall within the scope of protection of the present invention. When the embodiments provide numerical ranges, it should be understood that, unless otherwise specified in the present invention, the two endpoints of each numerical range and any numerical value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those of ordinary skill in the art to which the present invention belongs.

[0053] The present invention is further described below by way of specific examples. Unless otherwise specified, the various chemical reagents used in the examples of the present invention were obtained through conventional commercial channels.

[0054] In the following examples, the tea saponin surfactant was purchased from Macklin, S817817; the polyacrylamide (molecular weight 5 million) was purchased from Macklin, P821239; and the phenolic crosslinking agent was purchased from Macklin, P832682.

[0055] The average particle size of the rubber particles is 30 mesh and the density is 1.94 g / cm 3 .

[0056] For the above components, products from different manufacturers have no significant impact on the effects.

[0057] Example 1

[0058] A rubber particle-enhanced gel foam system comprises the following components in parts by weight: 0.7 parts of tea saponin surfactant, 0.4 parts of polyacrylamide (molecular weight of 5 million), 0.5 parts of phenolic crosslinking agent (phenolic resin), 2 parts of rubber particles and 100 parts of formation water.

[0059] The preparation method of the gel foam system comprises the steps of:

[0060] (1) Add polyacrylamide to formation water and stir uniformly at a stirring speed of 1500 rpm for 5 h to form a uniform polymer solution;

[0061] (2) Adding rubber particles to the polymer solution obtained in step (1). The rubber particles have a high density and are prone to sedimentation. Therefore, to prevent them from sedimentation, stirring is performed at a high speed of 1500 rpm for 30 minutes to mix them evenly, thereby obtaining a polymer solution containing rubber particles.

[0062] (3) Adding tea saponin surfactant to the polymer solution containing rubber particles, stirring at a low speed of 500 rpm for 10 minutes to prevent foaming, and mixing the mixture evenly to obtain a polymer solution containing rubber particles and surfactant;

[0063] (4) adding a phenolic crosslinking agent to the polymer solution containing rubber particles and a surfactant, and stirring at high speed for 1 minute at a speed of 1500 rpm to uniformly mix the polymer and the crosslinking agent to prevent the polymer and the crosslinking agent from crosslinking to form a gel, thereby obtaining a base liquid;

[0064] (5) The base liquid obtained in the above steps was added to a foam stirrer and stirred at a high speed of 8000 rpm for 3 min. At the same time, nitrogen was introduced during the stirring process to prevent excessive viscosity from causing a decrease in foaming effect. After the stirring was completed, a gel foam system was obtained.

[0065] Example 2

[0066] The difference from Example 1 is that the weight of the rubber particles in the gel foam system is different, which is 5 parts, specifically:

[0067] The gel foam system comprises the following components in parts by weight: 0.7 parts of tea saponin surfactant, 0.4 parts of polyacrylamide, 0.5 parts of phenolic crosslinking agent, 5 parts of rubber particles and 100 parts of formation water.

[0068] The rest are the same as in Example 1.

[0069] Example 3

[0070] The difference from Example 1 is that the weight of the rubber particles in the gel foam system is different, which is 10 parts, specifically:

[0071] The gel foam system comprises the following components in parts by weight: 0.7 parts of tea saponin surfactant, 0.4 parts of polyacrylamide, 0.5 parts of phenolic crosslinking agent, 10 parts of rubber particles and 100 parts of formation water.

[0072] The rest are the same as in Example 1.

[0073] Example 4

[0074] A rubber particle-enhanced gel foam system comprises the following components in parts by weight: 0.5 parts of tea saponin surfactant, 0.4 parts of polyacrylamide (molecular weight of 5 million), 0.5 parts of phenolic crosslinking agent (phenolic resin), 2 parts of rubber particles and 90 parts of formation water.

[0075] The preparation method of the gel foam system comprises the steps of:

[0076] (1) Add polyacrylamide to formation water and stir uniformly at a stirring speed of 1500 rpm for 4 h to form a uniform polymer solution;

[0077] (2) Adding rubber particles to the polymer solution obtained in step (1). The rubber particles have a high density and are prone to sedimentation. Therefore, to prevent them from sedimentation, stirring is performed at a high speed of 1500 rpm for 30 minutes to mix them evenly, thereby obtaining a polymer solution containing rubber particles.

[0078] (3) Adding tea saponin surfactant to the polymer solution containing rubber particles, stirring at a low speed of 500 rpm for 10 minutes to prevent foaming, and mixing the mixture evenly to obtain a polymer solution containing rubber particles and surfactant;

[0079] (4) adding a phenolic crosslinking agent to the polymer solution containing rubber particles and a surfactant, and stirring at high speed for 1 minute at a speed of 1500 rpm to uniformly mix the polymer and the crosslinking agent to prevent the polymer and the crosslinking agent from crosslinking to form a gel, thereby obtaining a base liquid;

[0080] (5) The base liquid obtained in the above steps was added to a foam stirrer and stirred at a high speed of 8000 rpm for 3 min. At the same time, nitrogen was introduced during the stirring process to prevent excessive viscosity from causing a decrease in foaming effect. After the stirring was completed, a gel foam system was obtained.

[0081] Example 5

[0082] A rubber particle-enhanced gel foam system comprises the following components in parts by weight: 0.7 parts of tea saponin surfactant, 0.5 parts of polyacrylamide (molecular weight of 5 million), 0.4 parts of phenolic crosslinking agent (phenolic resin), 2 parts of rubber particles and 110 parts of formation water.

[0083] The preparation method of the gel foam system comprises the steps of:

[0084] (1) Add polyacrylamide to formation water and stir uniformly at a stirring speed of 1500 rpm for 5 h to form a uniform polymer solution;

[0085] (2) Adding rubber particles to the polymer solution obtained in step (1). The rubber particles have a high density and are prone to sedimentation. Therefore, to prevent them from sedimentation, stirring is performed at a high speed of 1500 rpm for 30 minutes to mix them evenly, thereby obtaining a polymer solution containing rubber particles.

[0086] (3) Adding tea saponin surfactant to the polymer solution containing rubber particles, stirring at a high speed of 1500 rpm for 10 minutes to prevent foaming, and mixing the mixture evenly to obtain a polymer solution containing rubber particles and surfactant;

[0087] (4) adding a phenolic crosslinking agent to the polymer solution containing rubber particles and a surfactant, and stirring at high speed for 1 minute at a speed of 1500 rpm to uniformly mix the polymer and the crosslinking agent to prevent the polymer and the crosslinking agent from crosslinking to form a gel, thereby obtaining a base liquid;

[0088] (5) The base liquid obtained in the above steps was added to a foam stirrer and stirred at a high speed of 8000 rpm for 3 min. At the same time, nitrogen was introduced during the stirring process to prevent excessive viscosity from causing a decrease in foaming effect. After the stirring was completed, a gel foam system was obtained.

[0089] Comparative Example 1

[0090] Different from Example 1, the gel foam system does not include components of polyacrylamide and phenolic crosslinking agent.

[0091] Specifically, the invention discloses a gel foam system reinforced with rubber particles, which comprises the following components in parts by weight: 0.7 parts of tea saponin surfactant, 2 parts of rubber particles and 100 parts of formation water.

[0092] Comparative Example 2

[0093] The difference from Example 1 is that the preparation method of the gel foam system is different, specifically, nitrogen is not passed in step (5):

[0094] Steps (1)-(4): same as in Example 1;

[0095] (5) The base liquid obtained in the above steps was added to a foam stirrer and stirred at a high speed of 8000 rpm for 3 minutes to obtain a gel foam system.

[0096] Comparative Example 3

[0097] The difference from Example 1 is that the tea saponin surfactant in the gel foam system is replaced by a betaine surfactant (purchased from Macklin, B802317).

[0098] The rest are the same as in Example 1.

[0099] Comparative Example 4

[0100] The difference from Example 1 is that the type of crosslinking agent in the gel foam system is different. The crosslinking agent used in this comparative example is a mixture of 0.125 parts of hydroquinone (Shanghai MacLean Biochemical Technology Co., Ltd.) and 0.375 parts of hexamethylenetetramine (Guangzhou Yandi Biotechnology Co., Ltd.).

[0101] The rest are the same as in Example 1.

[0102] Comparative Example 5

[0103] The difference from Example 1 is that the molecular weight of the polyacrylamide in the gel foam system is different. The molecular weight of the polyacrylamide used in this comparative example is 22 million.

[0104] The rest are the same as in Example 1.

[0105] Comparative Example 6

[0106] The difference from Example 1 is that the weight parts of the components in the gel foam system are different, specifically, the components include: 0.3 parts of tea saponin surfactant, 0.4 parts of polyacrylamide, 0.8 parts of phenolic crosslinking agent, 2.1 parts of rubber particles and 100 parts of formation water.

[0107] The rest are the same as in Example 1.

[0108] Comparative Example 7

[0109] The difference from Example 1 is that the preparation method of the gel foam system is different, specifically comprising the following steps:

[0110] (1) Add polyacrylamide to formation water and stir uniformly at a stirring speed of 700 rpm for 1.5 h to form a uniform polymer solution;

[0111] (2) adding a phenolic crosslinker to the polymer solution obtained in step (1) and continuing stirring for 1 minute to obtain a mixture 1;

[0112] (3) Mixing mixture 1 with rubber particles and stirring for 90 min at a stirring speed of 700 rpm to uniformly mix the mixture to obtain mixture 2;

[0113] (3) Add tea saponin surfactant to mixture 2. To prevent foaming during stirring, stir at a low speed of 500 rpm for 90 minutes to mix the mixture evenly, thereby obtaining mixture 3.

[0114] (4) Mixture 3 was added to a foam stirrer and stirred at a high speed of 8000 rpm for 3 min. At the same time, nitrogen was introduced during the stirring process to prevent excessive viscosity from causing a decrease in foaming effect. After the stirring was completed, a gel foam system was obtained.

[0115] Comparative test

[0116] The obtained gel foam system stirred by the foam stirrer was poured into a graduated cylinder, and a stopwatch was turned on to record the foaming volume, the amount of particles settled to the bottom after 1 hour, and the liquid separation half-life.

[0117] The performance test results of the gel foam system of each embodiment and comparative example are shown in Table 1:

[0118] Table 1

[0119]

[0120] As can be seen from Table 1 above, the rubber particle-carrying gel foam system provided by the present invention has excellent foaming performance, half-life and particle-carrying capacity, and can meet the requirements of fractured oil and gas fields for plugging large fractures with particles to enhance recovery.

[0121] Schematic diagram of foaming of simple tea saponin surfactant Figure 1 As shown, the foaming volume is 400 ml; Figure 2 This is a diagram of the rubber particle-reinforced gel foam system prepared in Example 1 of the present invention, with a foaming volume of 325 ml.

[0122] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A rubber particle reinforced gel foam system, characterized in that: The invention comprises the following components: tea saponin surfactant, polyacrylamide, phenolic crosslinking agent, rubber particles and water.

2. The gel foam system according to claim 1, characterized in that The composition comprises the following components in parts by weight: 0.4-0.8 parts of tea saponin surfactant, 0.3-0.6 parts of polyacrylamide, 0.3-0.6 parts of phenolic crosslinking agent, 1-12 parts of rubber particles and 85-115 parts of water.

3. The gel foam system according to claim 2, characterized in that The composition comprises the following components in parts by weight: 0.5-0.7 parts of tea saponin surfactant, 0.4-0.5 parts of polyacrylamide, 0.4-0.5 parts of phenolic crosslinking agent, 2-10 parts of rubber particles and 90-110 parts of water.

4. The gel foam system according to claim 3, characterized in that The composition comprises the following components in parts by weight: 0.5-0.7 parts of tea saponin surfactant, 0.4 parts of polyacrylamide, 0.5 parts of phenolic crosslinking agent, 2-10 parts of rubber particles and 100 parts of water.

5. The gel foam system according to claim 4, characterized in that The composition comprises the following components in parts by weight: 0.7 parts of tea saponin surfactant, 0.4 parts of polyacrylamide, 0.5 parts of phenolic crosslinking agent, 2 parts of rubber particles and 100 parts of water.

6. The gel foam system according to any one of claims 1 to 5, characterized in that: The polyacrylamide is non-ionic polyacrylamide with a molecular weight of 5-15 million.

7. The gel foam system according to any one of claim 6, characterized in that: The molecular weight of the polyacrylamide is 5-10 million.

8. The gel foam system according to any one of claims 1 to 5, characterized in that: The phenolic crosslinking agent is selected from at least one of phenolic resin, a mixture of hydroquinone and hexamethylenetetramine, and a mixture of phenol and formaldehyde.

9. The gel foam system according to claim 8, characterized in that The phenolic crosslinking agent is phenolic resin.

10. The gel foam system according to any one of claims 1 to 5, characterized in that: The rubber particles have an average particle size of 20-40 mesh and a density of 1.9-2 g / cm 3 .

11. The gel foam system according to claim 10, characterized in that The rubber particles have an average particle size of 30 mesh and a density of 1.94 g / cm 3 .

12. The method for preparing the gel foam system according to any one of claims 1 to 11, characterized in that: Including steps: (1) mixing polyacrylamide with water and stirring to obtain a polymer solution; (2) mixing and stirring the polymer solution of step (1) with rubber particles to obtain a polymer solution containing rubber particles; (3) mixing and stirring the polymer solution containing rubber particles in step (2) with a tea saponin surfactant to obtain a polymer solution containing rubber particles and a surfactant; (4) mixing and stirring the polymer solution containing rubber particles and surfactant in step (3) with a crosslinking agent to obtain a base liquid; (5) The base liquid is stirred under nitrogen flow to obtain a gel foam system.

13. The preparation method according to claim 12, characterized in that In step (1), the stirring speed is 1000-2000 rpm and the stirring time is 4-6 h; In step (2), the stirring is carried out at a relatively high speed, the stirring speed is 1000-2000 rpm, and the stirring time is 20-40 min; In step (3), the stirring is carried out at a low speed, the stirring speed is 100-1000 rpm, and the stirring time is 5-20 min; in step (4), the stirring is carried out at a high speed, the stirring speed is 1000-2000 rpm, and the stirring time is 0.5-2 min; In step (5), the stirring is carried out at a high speed, the stirring speed is 7000-10000 rpm, and the stirring time is 2-5 min.

14. The preparation method according to claim 13, characterized in that In step (1), the stirring speed is 1500 rpm and the stirring time is 5 h; In step (2), the stirring speed is 1500 rpm and the stirring time is 30 min; In step (3), the stirring speed is 500 rpm and the stirring time is 10 min; In step (4), the stirring speed is 1500 rpm and the stirring time is 1 min; In step (5), the stirring speed is 8000 rpm and the stirring time is 3 min.

15. Use of the gel foam system according to any one of claims 1 to 11 in fracture-cavity carbonate reservoirs.

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