A compact reservoir anti-channeling secondary crosslinking cucurbituril hybrid polymer gel system

Abstract

The application belongs to the technical field of oil exploitation, and relates to a secondary cross-linking polymer gel system, in particular to a secondary cross-linking cucurbituril hybrid polymer gel system for preventing channeling of a tight oil reservoir. The cucurbituril hybrid polymer comprises the following raw materials: acrylamide, cucurbituril acrylate, N-vinyl imidazole and 2-acrylamido-dodecyl sulfonic acid. The cucurbituril hybrid polymer can be made into a polymer gel, and the polymer gel has good effects of reducing filtration loss and slowing down the damage of filtration loss liquid to a matrix. Then, the primary weak cross-linking gel enters the deep part of the oil reservoir, and slowly forms the secondary cross-linking gel, and the secondary cross-linking gel has good stability under high-temperature and high-salt conditions.

Description

Technical Field

[0001] This invention belongs to the field of petroleum extraction technology and relates to a secondary cross-linked polymer gel system, particularly a secondary cross-linked cucurbita urea hybrid polymer gel system for preventing channeling in tight oil reservoirs. Background Technology

[0002] Compared to conventional crude oil, tight oil is mostly concentrated near source rocks and is less affected by geological structures. Although the recoverable reserves of tight oil are large, the low permeability (0.01mD to 0.1mD), complex pore structure, poor pore throat connectivity, and strong microscopic heterogeneity of tight oil reservoirs make their extraction difficult.

[0003] Horizontal well volumetric fracturing is an effective method for developing tight oil reservoirs. However, after hydraulic fracturing in tight oil reservoirs, the locations of oil-enriched areas are complex, and the matrix permeability is much lower than the fracture permeability. Therefore, when further enhancing oil recovery, whether through water or gas drive, the injected medium is prone to channeling along the fractures, resulting in low sweep efficiency. To prevent channeling, maintain formation energy, and ensure a large production pressure differential, it is necessary to regulate the channeling pathway, directing the injected medium into the matrix with high oil saturation, increasing the swept volume, and improving displacement efficiency.

[0004] Currently, the commonly used fracture channeling prevention system is polymer gel, whose base fluid consists of high molecular weight polymers, crosslinking agents, and other additives. The crosslinking agent links multiple polymer molecules together through chemical reactions or physical interactions, including electrostatic interactions and van der Waals forces, ultimately forming a three-dimensional network structure under reservoir conditions. This structure retains "liquid-like" properties at the molecular scale and resembles a solid macroscopically. Due to the cross-scale permeability between fractures and adjacent matrix, during injection, some low-molecular-weight crosslinking agents and additives seep from the fractures into the matrix, causing matrix contamination, unstable gel performance within the fractures, and poor channeling prevention.

[0005] While existing polymer gel technologies exist, they are insufficient to meet the anti-channeling requirements of tight oil reservoirs. For example, Chinese patent application CN201110312551.8 discloses a high-mineralization polymer gel and its preparation method. The preparation method involves uniformly dispersing partially hydrolyzed polyacrylamide (HPAM) dry powder in a solvent water and stirring for 2 hours. The mass concentration of the partially hydrolyzed polyacrylamide is 0.05%–0.50%. A crosslinking agent, organic chromium, is mixed with the polymer solution and stirred until homogeneous. 3+ The mass concentration to polymer mass concentration ratio is: Poly:Cr 3+ =180:1, the total mineralization of the solvent water is 30g / l to 180g / l, of which Ca 2+ and Mg 2+The ion concentration ranges from 0.01% to 1.00%. The mixture is gelled for 15 to 30 minutes under reservoir temperature conditions or at 25°C to 85°C, and then injected into the formation or core.

[0006] Chinese patent application CN201811358571.7 discloses a high-temperature resistant polymer gel that forms at medium and low temperatures, its preparation method, and its application. The high-temperature resistant polymer gel that forms at medium and low temperatures is made from raw materials comprising the following components: acrylamide-2-acrylamido-2-methylpropanesulfonic acid-vinylpyrrolidone terpolymer, a heat stabilizer, a crosslinking agent, resorcinol, hexamethylenetetramine, and water; wherein the heat stabilizer is thiourea and cobalt chloride; and the crosslinking agent is chromium acetate or zirconium acetate. The gelling strength reaches grade G or above at medium and low temperatures, and it can be stable for 90 days at temperatures of 140℃ and above, meeting the requirements for plugging operations in steam-driven reservoirs at medium and low temperatures. It has good application prospects in plugging high-permeability layers in steam-driven reservoirs at medium and low temperatures, and can significantly improve oil recovery.

[0007] The purpose of this invention is to address the problems of filtration loss, matrix contamination, and unstable gel performance during conventional in-situ polymer gel mother liquor injection in tight oil reservoirs, by providing a secondary crosslinked cucurbita-urea hybrid polymer gel system. During surface preparation, this system forms a primary weakly crosslinked three-dimensional network structure through physical-chemical dual crosslinking. After pumping into the formation, it effectively reduces filtration loss and mitigates matrix damage from the filtrate. Subsequently, the primary weakly crosslinked gel penetrates deep into the reservoir, slowly forming a secondary crosslinked gel. Due to the introduction of rigid cucurbita, vinylimidazole, and the temperature- and salt-resistant monomer 2-acrylamido-dodecyl sulfonic acid, it maintains good stability under high-temperature and high-salt conditions. Summary of the Invention

[0008] To address the above technical problems, this invention provides a secondary crosslinked cucurbita hybrid polymer gel, which has a good effect on reducing filtrate loss and mitigating the damage of the filtrate to the matrix; subsequently, the primary weakly crosslinked gel enters the deep reservoir and slowly forms a secondary crosslinked gel, and maintains good stability under high temperature and high salinity conditions.

[0009] To achieve the above objectives, the technical solution provided by this invention is as follows:

[0010] A cucurbita-urea hybrid polymer comprises the following raw materials: acrylamide, cucurbitacin, N-vinylimidazole, and 2-acrylamido-dodecyl sulfonic acid.

[0011] Preferably, the cucurbita hybrid polymer, by molar amount, comprises the following raw materials: 0.25-0.45 parts acrylamide, 0.01-0.05 parts cucurbitacrylate, 0.05-0.1 parts N-vinylimidazole, and 0.05-0.1 parts 2-acrylamido-dodecyl sulfonic acid.

[0012] Preferably, the cucurbita-urea hybrid polymer has a viscosity-average molecular weight of 3 million to 10 million, a solid content of 95%, and the number of glycourea structural units in the cucurbita is 5, 6, 7, or 8. The structure of the cucurbita-urea hybrid polymer is shown below:

[0013]

[0014] Where x, y, m, n are the degree of polymerization of monomers, and x:y:m:n = 0.25~0.45:0.01~0.05:0.05~0.1:0.05~0.1.

[0015] Another objective of this invention is to provide a method for preparing the cucurbituril hybrid polymer, comprising the following steps:

[0016] (1) Acrylamide, cucurbitacin acrylate, N-vinylimidazolium and 2-acrylamido-dodecyl sulfonic acid were added to deionized water in a molar ratio to obtain a monomer solution;

[0017] (2) Add an initiator and react to obtain the cucurbita hybrid polymer.

[0018] Preferably, in (1), the total mass concentration of acrylamide, cucurbitacin, N-vinylimidazolium and 2-acrylamido-dodecylsulfonic acid in the monomer solution is 20% to 30%.

[0019] Preferably, in (2), the initiator is azobisisobutylamidine hydrochloride.

[0020] Preferably, the amount of the initiator is 0.01-0.05% of the total mass of acrylamide, cucurbitacin, N-vinylimidazole and 2-acrylamido-dodecylsulfonic acid.

[0021] Preferably, in (2), after adding the initiator, an inert gas is introduced for 30-60 minutes, and the inert gas is nitrogen or helium.

[0022] Preferably, in (2), the reaction is carried out under sealed conditions.

[0023] Preferably, the reaction temperature is 40-60℃ and the reaction time is 4-8h.

[0024] Another objective of this invention is to provide the application of the cucurbita hybrid polymer in the preparation of secondary crosslinked cucurbita hybrid polymer gels.

[0025] The present invention also aims to provide a secondary crosslinked cucurbita hybrid polymer gel, comprising the following components: cucurbita hybrid polymer, primary crosslinking agent, secondary crosslinking agent, activator, and high temperature stabilizer.

[0026] Preferably, the crosslinked cucurbita hybrid polymer gel, by mass percentage, comprises the following components: 0.2-2% cucurbita hybrid polymer, 0.01-0.03% primary crosslinking agent, 0.1-1% secondary crosslinking agent, 0.05-0.2% activator, 0.05-5% high-temperature stabilizer, and the remainder being water.

[0027] Preferably, the cross-linked cucurbitaurea hybrid polymer gel, by weight percentage, comprises the following components:

[0028] Preferably, the primary crosslinking agent is any one or more of organic chromium, aluminum citrate, aluminum sulfate, methyl phenolic resin, catechol, resorcinol, hexamethylenetetramine, and oxalic acid-modified rare earth chloride.

[0029] Preferably, the secondary crosslinking agent is any one or more of organic phenolic resin, water-soluble polyethyleneimine, formaldehyde, paraformaldehyde, borax, nano-zirconium diboride, alkali-catalyzed phenolic resin, and chloropropylene phenolic resin.

[0030] Preferably, the high-temperature stabilizer is any one or more of nano-sodium bentonite, polyethylene glycol, polyvinyl alcohol, and PA fiber.

[0031] Preferably, the activator is any one or more of ammonium acetate, ammonium chloride, ammonium bicarbonate, and citric acid.

[0032] Another objective of this invention is to provide a method for preparing the secondary crosslinked cucurbita urea hybrid polymer gel, comprising the following steps:

[0033] S1. Prepare a cucurbita urea hybrid polymer solution;

[0034] S2. Dilute the cucurbita hybrid polymer solution with water to the required concentration, add a high temperature stabilizer and an activator, and then add a primary crosslinking agent and a secondary crosslinking agent in sequence to obtain the secondary crosslinked cucurbita hybrid polymer gel.

[0035] Another objective of this invention is to provide the application of the cucurbita hybrid polymer or the secondary cross-linked cucurbita hybrid polymer gel in preventing gas channeling in gas-driven tight oil reservoirs.

[0036] Compared with the prior art, the technical advantages of the present invention are as follows:

[0037] (1) The present invention provides a cucurbita hybrid polymer that can be used to prepare a secondary crosslinked cucurbita hybrid polymer gel. This polymer gel overcomes the problems of high filtration loss, poor stability and weak deep transport ability of conventional polymer gel systems.

[0038] Under surface conditions (15–35℃), the cucurbita-urea hybrid polymer first forms a physical cross-linked network structure through hydrophobic association and host-guest inclusion. Subsequently, it densifies the three-dimensional network structure through chemical cross-linking with a primary cross-linking agent. The chemical cross-linking time is controllable (1–5 h), and the viscosity after primary gelation is 20 mPa·s–500 mPa·s. It exhibits good injection performance, low matrix damage (matrix damage rate less than 20%), and can propagate along fractures. Then, under reservoir conditions (35℃–120℃), secondary cross-linking occurs, with a controllable gelation time (5 days–30 days). The resulting secondary cross-linked gel has a strength of F–H, meeting reservoir anti-channeling requirements. The addition of an activator lowers the activation energy of the primary cross-linking agent at low temperatures, enabling primary cross-linking to form a weakly cross-linked gel network at lower temperatures. The addition of a high-temperature stabilizer enhances the gel strength while imparting a high-temperature (120℃) and high-salt (20 × 10⁻⁶) characteristic to the gel system. 4 It exhibits good long-term stability under conditions of mg / L.

[0039] (2) The cucurbita hybrid polymer used in this invention is a supramolecular polymer with a small molecular weight and a fast dissolution rate during solution preparation, allowing for direct injection with produced water. The polymer molecular chain incorporates rigid cucurbita and vinylimidazole, as well as the flexible, water-soluble hydrophobic monomer 2-acrylamidododecyl sulfonic acid, endowing the supramolecular polymer with intermolecular hydrophobic association and host-guest inclusion. The nonlinear structure provides the polymer with excellent shear resistance. Furthermore, the rigid cucurbita and vinylimidazole maintain a large hydrodynamic size of the polymer under high temperature and high salinity conditions, ultimately ensuring good stability under these conditions.

[0040] (3) The secondary crosslinked cucurbita hybrid polymer gel system provided by the present invention is a secondary crosslinked system, which is beneficial to reduce damage to the matrix and can be well applied to the prevention of channeling in tight oil reservoirs. Detailed Implementation

[0041] The present invention will be described below through specific embodiments to make the technical solution of the present invention easier to understand and master, but the present invention is not limited thereto. Unless otherwise specified, the experimental methods described in the following embodiments are conventional methods; unless otherwise specified, the reagents and materials are all commercially available; and different sources do not have a significant impact on product performance.

[0042] Example 1

[0043] A method for preparing a cucurbituril hybrid polymer includes the following steps:

[0044] (1) Acrylamide, cucurbitacin, N-vinylimidazolium and 2-acrylamido-dodecyl sulfonic acid were added to deionized water in a molar ratio of 0.3:0.02:0.05:0.08. After the solution became clear and transparent, deionized water was added to maintain the total mass concentration of monomers at 25%.

[0045] (2) Add azobisisobutylamidine hydrochloride initiator with a monomer mass concentration of 0.01% under stirring conditions; after passing N2 through for 30 minutes, seal the solution, heat to 40℃ and react for 4 hours, then crush, dry and granulate to obtain cucurbita urea hybrid polymer.

[0046] Example 2

[0047] A method for preparing a cucurbituril hybrid polymer includes the following steps:

[0048] (1) Acrylamide, cucurbitacin, N-vinylimidazolium and 2-acrylamido-dodecyl sulfonic acid were added to deionized water in a molar ratio of 0.25:0.01:0.05:0.05. After the solution became clear and transparent, deionized water was added to maintain the total mass concentration of monomers at 20%.

[0049] (2) Add azobisisobutylamidine hydrochloride initiator with a monomer mass concentration of 0.05% under stirring conditions; after passing N2 through for 30 minutes, seal the solution, heat to 60℃ and react for 4 hours, then crush, dry and granulate to obtain cucurbita urea hybrid polymer.

[0050] Example 3

[0051] A method for preparing a cucurbituril hybrid polymer includes the following steps:

[0052] (1) Acrylamide, cucurbitacin, N-vinylimidazolium and 2-acrylamido-dodecyl sulfonic acid were added to deionized water in a molar ratio of 0.45:0.05:0.1:0.1. After the solution became clear and transparent, deionized water was added to maintain the total mass concentration of monomers at 30%.

[0053] (2) Add azobisisobutylamidine hydrochloride initiator with a monomer mass concentration of 0.01% under stirring conditions; after passing N2 through for 60 minutes, seal the solution, heat to 80℃ and react for 4 hours, then crush, dry and granulate to obtain cucurbita urea hybrid polymer.

[0054] Example 4

[0055] The performance test and experimental steps are as follows:

[0056] (1) Prepare polymer solutions using a mixing method. Prepare polymer solutions of the maximum concentration required for the experiment. Dilute the mother liquor to the required concentration before use. Calculate the amount of polymer needed to prepare a certain volume of polymer mother liquor. Add the appropriate amount of polymer to water and place it under an electric stirrer to generate eddies. Then, add the weighed polymer powder to the water at a uniform and slow speed to avoid rapid addition that could form "fish eyes". Stir at a moderate speed until the polymer is fully swollen and let it stand for 12 hours before use.

[0057] (2) Prepare the base liquid of the secondary crosslinking gel system according to the following ratio: 0.5% to 1.5% cucurbita hybrid polymer (polymer is the polymer obtained in Example 1, with a viscosity-average molecular weight of 3 million, x:y:m:n = 0.3:0.02:0.05:0.08) + 0.02% primary crosslinking agent resorcinol + 0.5% secondary crosslinking agent organic phenolic resin + 0.2% activator ammonium acetate + 5% high temperature stabilizer nano sodium bentonite, the remainder being water;

[0058] (3) After preparation, the viscosity of the mother liquor was tested at 15℃. After standing for 2 hours, the viscosity of the first cross-linking system was tested. Then, it was placed in an oven at 120℃ and the strength of the gel was observed by the gel code method (refer to: Tan Xin. Study on the evaluation of secondary gel system and profile control performance of low temperature conglomerate reservoir. Southwest Petroleum University, 2018.) (Table 1). The experimental results are shown in Table 2. After standing for 2 hours at 15℃, the base liquid underwent a first cross-linking reaction to form a weak cross-linking network, and the viscosity of the system increased. After aging for 60 days, no dehydration occurred (no dehydration indicates strength), and the system maintained a high strength.

[0059] Table 1. Standard Gel Strength Code

[0060]

[0061] Table 2. Gelation Properties

[0062]

[0063] Example 5

[0064] The matrix damage caused by gel loss was studied using fracture core displacement experiments. The damage of the secondary cross-linked gel system and the primary cross-linked gel system were compared. The experimental steps are as follows:

[0065] (1) After testing the matrix permeability of the core (0.16mD), the core was fractured, the fracture was saturated with formation water, and placed in the core holder.

[0066] (2) Formation water was injected into the core at a rate of 0.5 mL / min, and the permeability of the fracture was tested to be 3.4 D;

[0067] (3) Inject the secondary gel system after one crosslinking (the gel system with a polymer concentration of 1.5% in Example 4) and the system without the primary crosslinking agent into the core at a rate of 0.5 mL / min, record the pressure change, and take out the core after the displacement pressure stabilizes.

[0068] (4) After scraping away the quartz sand and gel in the core fracture and bonding the fracture wall, the matrix permeability of the core was tested again (0.15mD). The damage to the matrix by the secondary cross-linked gel system was 6.25%, while the matrix damage rate of the conventional gel system was 23.4%.

[0069] To visually measure the filtration loss of the system, a FADLT-1 type fracturing and acidizing working fluid dynamic filtration loss analyzer was used to study the filtration loss of the secondary gel system after primary crosslinking (where the polymer concentration was 1.5%) and the system without primary crosslinking agent. The initial filtration loss and the cumulative filtration loss after 2 hours were 0.015 m³ / h. 3 / m 2 1.5 mL; 0.05 mL 3 / m 2 The result of 3.6 mL indicates that the secondary cross-linking system can significantly reduce filtration loss and has a certain protective effect on the matrix.

[0070] Example 6

[0071] The experimental steps are as follows:

[0072] (1) Prepare polymer solutions using a mixing method. Prepare polymer solutions of the maximum concentration required for the experiment. Dilute the stock solution to the required concentration before use. Calculate the amount of polymer needed to prepare a certain volume of polymer stock solution. Add the required amount of polymer to water and place it under an electric stirrer to generate eddies. Then, add the weighed polymer powder to the water at a uniform and slow speed to avoid rapid addition that could form "fish eyes". Stir at a moderate speed until the polymer is fully swollen, and then let it stand for 12 hours before use.

[0073] (2) Prepare the stock solution of the secondary crosslinking gel system according to the following ratio: 0.1% to 0.3% cucurbita hybrid polymer (polymer is the polymer obtained in Example 3, with a viscosity-average molecular weight of 8 million, x:y:m:n = 0.45:0.05:0.1:0.1) + 0.02% primary crosslinking agent hexamethylenetetramine + 0.5% polyethylene glycol modified high ortho-phenolic resin + 0.1% activator citric acid + 2% high temperature stabilizer polyvinyl alcohol, the remainder being water;

[0074] (3) After preparation, the viscosity of the mother liquor was tested at 20℃. After standing for 2 hours, the viscosity of the crosslinking system was tested again. Then, it was placed in an oven at 90℃, and the gel strength was observed by gel coding method. The experimental results are shown in Table 3. After standing for 2 hours at 20℃, the base liquor underwent a crosslinking reaction to form a weak crosslinking network, and the viscosity of the system increased. After aging for 60 days, no dehydration occurred, and the system maintained high strength.

[0075] Table 3. Gelation Properties

[0076]

[0077] Example 7

[0078] The matrix damage caused by gel loss was studied using fracture core displacement experiments. The damage of the secondary cross-linked gel system and the primary cross-linked gel system were compared. The experimental steps are as follows:

[0079] (1) After testing the matrix permeability of the core (0.18mD), the core was fractured, the fracture was saturated with formation water, and placed in the core holder.

[0080] (2) Formation water was injected into the core at a rate of 0.5 mL / min, and the permeability of the fracture was tested to be 3.6 D;

[0081] (3) Inject the secondary gel system after one crosslinking (the gel system with a polymer concentration of 0.3% in Example 6) and the system without the primary crosslinking agent into the core at a rate of 0.5 mL / min, record the pressure change, and take out the core after the displacement pressure stabilizes.

[0082] (4) After scraping away the quartz sand and gel in the core fracture and bonding the fracture wall, the matrix permeability of the core was tested again and found to be 0.17 mD. The damage to the matrix by the secondary cross-linked gel system was 5.6%, while the matrix damage rate of the system without the primary cross-linking agent was 20.15%.

[0083] To visually measure the filtration loss of the system, a FADLT-1 type fracturing and acidizing working fluid dynamic filtration loss analyzer was used to study the filtration loss of the secondary gel system after primary crosslinking (where the polymer concentration was 0.3%) and the system without primary crosslinking agent. The initial filtration loss and the cumulative filtration loss after 2 hours were 0.004 m³ / h. 3 / m 2 0.5 mL; 0.028 m 3 / m 2 The 2.1 mL result indicates that the formation of a gel during ground sample preparation can effectively reduce the filtration loss of the system and has a certain protective effect on the matrix.

[0084] The above detailed description is a specific description of one of the feasible embodiments of the present invention. This embodiment is not intended to limit the patent scope of the present invention. All equivalent implementations or modifications that do not depart from the present invention should be included within the scope of the technical solution of the present invention.

Claims

1. A cucurbita urea hybrid polymer, characterized in that, Based on molar amounts, the cucurbita-urea hybrid polymer comprises the following raw materials: 0.25-0.45 parts acrylamide, 0.01-0.05 parts cucurbitacin, 0.05-0.1 parts N-vinylimidazole, and 0.05-0.1 parts 2-acrylamido-dodecyl sulfonic acid; The structure of the cucurbita-urea hybrid polymer is shown below: Where x, y, m, n are the degree of polymerization of monomers, and x:y:m:n = 0.25-0.45:0.01-0.05:0.05-0.1:0.05-0.

1.

2. The cucurbita-urea hybrid polymer as described in claim 1, characterized in that, The cucurbita-urea hybrid polymer has a viscosity-average molecular weight of 3 million to 10 million and a solid content of 95%.

3. A method for preparing the cucurbita-urea hybrid polymer as described in claim 1 or 2, characterized in that, Includes the following steps: (1) Acrylamide, cucurbitacin, N-vinylimidazolium, and 2-acrylamido-dodecyl sulfonic acid were added to deionized water in a molar ratio to obtain a monomer solution; (2) Add an initiator and react to obtain the cucurbituril hybrid polymer.

4. The method for preparing the cucurbita-urea hybrid polymer as described in claim 3, characterized in that, In (1), the total mass concentration of acrylamide, cucurbitacin, N-vinylimidazolium and 2-acrylamido-dodecylsulfonic acid in the monomer solution is 20%-30%.

5. The method for preparing the cucurbita-urea hybrid polymer as described in claim 3, characterized in that, In (2), the initiator is azobisisobutylamidine hydrochloride.

6. The method for preparing the cucurbita-urea hybrid polymer as described in claim 3, characterized in that, The amount of the initiator is 0.01-0.05% of the total mass of acrylamide, cucurbitacin, N-vinylimidazolium and 2-acrylamido-dodecylsulfonic acid.

7. The method for preparing the cucurbita-urea hybrid polymer as described in claim 3, characterized in that, (2) In the step of adding the initiator, an inert gas is introduced for 30-60 minutes, and the inert gas is nitrogen or helium.

8. The method for preparing the cucurbita-urea hybrid polymer as described in claim 3, characterized in that, The reaction temperature is 40-60℃, and the reaction time is 4-8h.

9. The application of the cucurbita hybrid polymer prepared by the method of claim 1 or 2 or any of the cucurbita hybrid polymers of claims 3-8 in the preparation of secondary crosslinked cucurbita hybrid polymer gels.

10. A secondary crosslinked cucurbita hybrid polymer gel, comprising the following components: the cucurbita hybrid polymer prepared by the preparation method of the cucurbita hybrid polymer as described in claim 1 or 2 or any of the cucurbita hybrid polymers as described in claims 3-8, a primary crosslinking agent, a secondary crosslinking agent, an activator, and a high-temperature stabilizer.

11. The secondary crosslinked cucurbita urea hybrid polymer gel according to claim 10, characterized in that, The crosslinked cucurbita hybrid polymer gel, by mass percentage, comprises the following components: 0.2-2% cucurbita hybrid polymer, 0.01-0.03% primary crosslinking agent, 0.1-1% secondary crosslinking agent, 0.05-0.2% activator, 0.05-5% high-temperature stabilizer, and the remainder being water.

12. The secondary crosslinked cucurbita urea hybrid polymer gel as described in claim 10, characterized in that, The primary crosslinking agent is any one or more of organic chromium, aluminum citrate, aluminum sulfate, methyl phenolic resin, catechol, resorcinol, hexamethylenetetramine, and oxalic acid-modified rare earth chloride; the secondary crosslinking agent is any one or more of organic phenolic resin, water-soluble polyethyleneimine, formaldehyde, paraformaldehyde, borax, nano-zirconium diboride, alkali-catalyzed phenolic resin, and chloropropylene phenolic resin.

13. The secondary crosslinked cucurbita urea hybrid polymer gel as described in claim 10, characterized in that, The high-temperature stabilizer is any one or more of nano-sodium bentonite, polyethylene glycol, polyvinyl alcohol, and PA fiber.

14. The secondary crosslinked cucurbita urea hybrid polymer gel as described in claim 10, characterized in that, The activator is any one or more of ammonium acetate, ammonium chloride, ammonium bicarbonate, and citric acid.

15. A method for preparing a secondary crosslinked cucurbita urea hybrid polymer gel as described in any one of claims 10-14, comprising the following steps: S1. Prepare a cucurbita urea hybrid polymer solution; S2. Dilute the cucurbita hybrid polymer solution with water to the required concentration, add a high temperature stabilizer and an activator, and then add a primary crosslinking agent and a secondary crosslinking agent in sequence to obtain the secondary crosslinked cucurbita hybrid polymer gel.

16. The application of the cucurbita hybrid polymer as described in claim 1 or 2, or the cucurbita hybrid polymer gel as described in any one of claims 10-14, in preventing gas channeling in gas-driven tight oil reservoirs.

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