Plugging material for liquid carbon dioxide injection well oil jacket annulus and preparation method and application thereof

Abstract

The invention provides a plugging material for an oil jacket annulus of a liquid carbon dioxide injection well and a preparation method and application thereof, the plugging material for the oil jacket annulus of the liquid carbon dioxide injection well is a mixture of C6-C60 alkane and asphalt, and the mixture comprises the following components in percentage by weight: 60-65 wt% of C6-C36 alkane, 25-30 wt% of C37-C60 alkane and 5-10 wt% of asphalt. The preparation method of the plugging material is simple, the cost is saved, the plugging material has a long-time effective plugging effect, the well control risk is reduced, and therefore the plugging material is suitable for large-scale production and has wide industrial application prospects.

Description

Technical Field

[0001] This application relates to the field of petroleum development technology, and in particular to a plugging material for the annulus of a well injected with liquid carbon dioxide, its preparation method, and its application. Background Technology

[0002] In the oil and gas field sector, gas-driven technology, particularly carbon dioxide miscible flooding, works by injecting carbon dioxide into the oil reservoir to form a miscible front. This allows the carbon dioxide to mix with the crude oil, increasing its flowability and thus improving oil recovery. This technology not only enhances reservoir recovery while achieving effective carbon sequestration but also significantly contributes to stable oil production and economic benefits. Especially in low-permeability reservoirs, the high fluidity and easy solubility of carbon dioxide in crude oil make it an effective way to improve recovery. Furthermore, injecting carbon dioxide mixed with foam increases the carbon dioxide sweep volume and reservoir activation, improving reservoir recovery by 2-3 percentage points compared to injecting carbon dioxide alone.

[0003] However, the current application of carbon dioxide miscible flooding in oilfields also faces many problems: During the development of low-permeability reservoirs, high gas injection pressure leads to high pressure in the injection well casing. To reduce casing pressure in injection wells, existing technologies typically involve adding packers above the injection layer and slow-release scale inhibitors to the annulus. However, after a period of operation, due to the small molecular weight of carbon dioxide, micro-leakage occurs in the packer tubing, causing the casing pressure in the injection well to continuously rise, eventually reaching the same level as the oil pressure, thus creating significant well control risks at the wellhead. To reduce the casing pressure at the wellhead, the only option is to periodically vent gas through the casing gate valve, which not only causes environmental pollution but also poses significant safety hazards.

[0004] Therefore, existing technologies for plugging the annulus in wells using liquid carbon dioxide injection suffer from poor plugging effectiveness and well control risks. Consequently, there is an urgent need to provide a plugging material and preparation method for the annulus in wells using liquid carbon dioxide injection to address these issues. Summary of the Invention

[0005] The main objective of this invention is to provide a plugging material, preparation method, and application for the annulus of a well injected with liquid carbon dioxide, in order to solve the technical problems of poor plugging effect and well control risks in the existing plugging technology for the annulus of a well injected with liquid carbon dioxide.

[0006] To achieve the above objectives, according to one aspect of the present invention, a plugging material for the annulus of a well injected with liquid carbon dioxide is provided. The plugging material is a mixture of C6-C60 alkanes and bitumen. By weight percentage, the alkane mixture comprises: 60-65 wt% C6-C36 alkanes, 25-30 wt% C37-C60 alkanes, and 5-10 wt% bitumen.

[0007] Furthermore, among the C6 to C36 alkanes, by weight percentage, C6 alkanes, C7 alkanes, C8 alkanes, C9 alkanes, C10 alkanes, C11 alkanes, C12 alkanes, C13 alkanes, C14 alkanes, C15 alkanes, C16 alkanes, C17 alkanes, C18 alkanes, C19 alkanes, C20 alkanes, C21 alkanes, C22 alkanes, C23 alkanes, C24 alkanes, C25 alkanes, C26 alkanes, C27 alkanes, C28 alkanes, C29 alkanes, C30 alkanes, C31 alkanes, C32 alkanes, C33 alkanes, C34 alkanes, C35 alkanes, and C36 alkanes each independently account for 0.7% to 4.5% of the total mass of the mixture of C6 to C60 alkanes and asphalt.

[0008] Furthermore, the sealing material has a freezing point of 52–55°C, an ignition point of 200–300°C, and a distillation temperature of 120–160°C.

[0009] Furthermore, the moisture content of the sealing material is 0–0.05%, and the salt content is 0–20 mg / L.

[0010] Furthermore, the viscosity of the sealing material is 30–60 mPa·s at 60°C, 1500–2500 mPa·s at 40°C, and 10000–15000 mPa·s at 20°C.

[0011] Furthermore, among the C6 to C36 alkanes, by weight percentage, C10 alkanes, C11 alkanes, C12 alkanes, C13 alkanes, C14 alkanes, C15 alkanes, C16 alkanes, C17 alkanes, C18 alkanes, C19 alkanes, C20 alkanes, C21 alkanes, C22 alkanes, C23 alkanes, C24 alkanes, C25 alkanes, C26 alkanes, C27 alkanes, C28 alkanes, C29 alkanes, C30 alkanes, C31 alkanes, C32 alkanes, C33 alkanes, and C34 alkanes each independently account for 1.7% to 2.3% of the total mass of the mixture of C6 to C60 mixed alkanes and asphalt.

[0012] To achieve the above objectives, according to one aspect of the present invention, a method for preparing a plugging material for the annulus of a well injected with liquid carbon dioxide is provided. The preparation method includes: taking 90-95% of C6-C60 alkanes for a first heat treatment, then taking 5-10% of asphalt for a second heat treatment, and mixing them in a vertical tank to obtain a plugging material for the annulus of a well injected with liquid carbon dioxide.

[0013] Furthermore, the mixing temperature is 60–70°C, and the mixing time is 24–36 h.

[0014] Furthermore, the temperature of the first heating treatment is 60-70℃, and the treatment time is 8-12h; preferably, the temperature of the second heating treatment is 80-90℃, and the treatment time is 4-6h.

[0015] According to another aspect of the present invention, a sealing material for the annulus of a well for liquid carbon dioxide injection, or a sealing material obtained by the preparation method of the above-described sealing material for the annulus of a well for liquid carbon dioxide injection, is provided for application in the fields of petroleum development, waterproofing and corrosion prevention, or cryogenic gas filling.

[0016] The sealing material for the annulus of wells injecting liquid carbon dioxide obtained by applying the technical solution of the present invention has a simple and cost-effective preparation method, and the sealing material has an effective sealing effect, reducing well control risks, thus making it suitable for large-scale production and having broad prospects for industrial application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0018] As described in the background section of this invention, existing sealing techniques for the annulus of wells injected with liquid carbon dioxide suffer from poor sealing performance and well control risks. Therefore, this invention provides a sealing material for the annulus of wells injected with liquid carbon dioxide. The sealing material is a mixture of C6-C60 alkanes and bitumen. By weight percentage, the mixed alkanes comprise: 60-65 wt% C6-C36 alkanes, 25-30 wt% C37-C60 alkanes, and 5-10 wt% bitumen.

[0019] In existing technologies, to reduce casing pressure in injection wells, packers are typically added above the injection layer, and slow-release scale inhibitors are added to the annulus to mitigate the aforementioned problems. However, after a period of operation, due to the small molecular weight of carbon dioxide, micro-leakage occurs in the packer tubing, causing the casing pressure in the injection well to continuously increase, eventually reaching the same level as the oil pressure, thus posing a significant well control risk at the wellhead. To reduce the casing pressure in the production tree, the only solution is to periodically vent the casing gate, which not only causes environmental pollution but also poses significant safety hazards. However, the sealing material used in this invention for the annulus of wells injecting liquid carbon dioxide is a mixture of C6-C60 alkanes and bitumen. By weight percentage, the mixed alkanes include: 60-65 wt% C6-C36 alkanes, 25-30 wt% C37-C60 alkanes, and 5-10 wt% bitumen. This plugging material has a high freezing point. It has good fluidity above the freezing point. When the temperature is below the freezing point, the liquid alkane mixture loses its fluidity and becomes a mixture of viscous and solid phases. This achieves the plugging of the annulus of liquid carbon dioxide oil casing, resulting in a good plugging effect and reducing well control risks.

[0020] In a preferred embodiment, the C6 to C36 alkanes, by weight percentage, comprise 0.7% to 4.5% of the total mass of the mixture of C6 to C60 alkanes and asphalt.

[0021] To further improve the sealing effect of the plugging material and reduce well control risks, the preferred sealing material has a freezing point of 52-55℃, an ignition point of 200-300℃, and a distillation temperature of 120-160℃; the water content of the sealing material is 0-0.05%, and the salt content is 0-20 mg / L.

[0022] In a preferred embodiment, the viscosity of the plugging material is 30-60 mPa·s at 60°C, 1500-2500 mPa·s at 40°C, and 10000-15000 mPa·s at 20°C. It has good fluidity above the freezing point. When the temperature is below the freezing point, the liquid alkane mixture loses its fluidity and becomes viscous and solid, thereby achieving the plugging of the annulus of liquid carbon dioxide oil casing, achieving a good plugging effect and reducing well control risks.

[0023] In a preferred embodiment, by weight percentage, C10 alkanes, C11 alkanes, C12 alkanes, C13 alkanes, C14 alkanes, C15 alkanes, C16 alkanes, C17 alkanes, C18 alkanes, C19 alkanes, C20 alkanes, C21 alkanes, C22 alkanes, C23 alkanes, C24 alkanes, C25 alkanes, C26 alkanes, C27 alkanes, C28 alkanes, C29 alkanes, C30 alkanes, C31 alkanes, C32 alkanes, C33 alkanes, and C34 alkanes each independently account for 1.7% to 2.3% of the total mass of the mixture of C6 to C60 mixed alkanes and asphalt.

[0024] Another aspect of this invention provides a method for preparing a plugging material for the annulus of a liquid carbon dioxide injection well. The method includes: subjecting 90-95% of C6-C60 alkanes to a primary heat treatment, followed by a secondary heat treatment of 5-10% asphalt, and then mixing the mixture in a vertical tank to obtain the plugging material for the annulus of a liquid carbon dioxide injection well. This preparation method is simple, easy to operate, and has low production costs, making it suitable for large-scale production. Furthermore, the plugging material obtained by this method exhibits superior plugging performance.

[0025] In a preferred embodiment, the mixing temperature in the preparation method of the plugging material for the annulus of a well injected with liquid carbon dioxide is 65-70°C, the mixing time is 24-36 hours, the temperature of the first heating treatment is 60-70°C, the treatment time is 8-12 hours, and the temperature of the second heating treatment is 80-90°C, the treatment time is 4-6 hours, so that the C6-C60 alkanes and asphalt are mixed evenly and thoroughly to improve the plugging performance of the plugging material.

[0026] In a preferred embodiment, the above-mentioned plugging material for the annulus of a liquid carbon dioxide injection well is used in the following method for plugging a liquid carbon dioxide injection well: Step S1, scraping the well to be plugged, and thoroughly reverse-circulating the wellbore with well-washing fluid until the inlet and outlet fluids are consistent, and testing the formation water absorption index; Step S2: connecting the tubing pipes one by one to form a channel, lowering it to a position 100-300m above the injection section, and installing the wellhead Christmas tree; Step S3: using a cement pump truck to connect the wellhead pipe. Step S2: The sealing material is injected from the surface tanker into the annulus through the casing gate, entering through the casing gate and circulating out through the tubing gate back into the tanker. The circulating sealing material used is 1.5 to 2.5 times the wellbore volume. Step S4: Liquid carbon dioxide is injected into the formation through the tubing, with the injection volume being more than 20 times the tubing volume. Step S5: After 72 hours, the casing pressure is tested. If the casing pressure is 0 or below 1 MPa, the sealing is successful. If unsuccessful, steps S2 and S3 are repeated. Next, during the well inspection, injection is first stopped. After 72 hours, the well is flushed using positive circulation tubing at a flushing fluid temperature of 75-85°C. The sealing material is then circulated back into the tanker to release the seal.

[0027] Another aspect of the present invention provides a sealing material for the annulus of a well for liquid carbon dioxide injection, or a sealing material obtained by the preparation method of the sealing material for the annulus of a well for liquid carbon dioxide injection, which is used in the field of petroleum development, waterproofing and corrosion protection or cryogenic gas filling.

[0028] The present application will be further described in detail below with reference to specific embodiments, which should not be construed as limiting the scope of protection claimed in the present application.

[0029] Example 1

[0030] The liquid carbon dioxide injection well was selected from a well in the Bayan Oilfield. First, the well was cleaned, scraped, and its water absorption index was tested. Then, tubing was installed and treated to meet the design requirements. Subsequently, a cement truck was used to inject the sealing material from the casing inlet tubing. This process thoroughly circulated the wellbore and other impurities to the surface, with the amount of sealing material being twice the wellbore volume.

[0031] The aforementioned sealing material is a mixture of C6-C60 mixed alkanes and asphalt. By weight percentage, the mixed alkanes include: 62 wt% C6-C36 alkanes, 30 wt% C37-C60 alkanes, and 8 wt% asphalt. The asphalt composition by weight also includes: C6 alkanes, C7 alkanes, C8 alkanes, C9 alkanes, C10 alkanes, C11 alkanes, C12 alkanes, C13 alkanes, C14 alkanes, C15 alkanes, C16 alkanes, C17 alkanes, C18 alkanes, C19 alkanes, C20 alkanes, C21 alkanes, C22 alkanes, C23 alkanes, C24 alkanes, C25 alkanes, C26 alkanes, C27 alkanes, C28 alkanes, C29 alkanes, C30 alkanes, C31 alkanes, and C32 alkanes. C33, C34, C35, and C36 alkanes each independently account for 0.7% to 4.2% of the total mass of the mixture of C6-C60 mixed alkanes and asphalt. Among them, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C30, C31, C32, C33, and C34 alkanes each independently account for 1.8% to 2.1% of the total mass of the mixture of C6-C60 mixed alkanes and asphalt. The above-mentioned C6-C60 mixed alkanes were heated once at 65℃ for 11 hours, and the above-mentioned asphalt was heated a second time at 85℃ for 5 hours. The two mixtures were then combined in a vertical tank and injected into the wellbore via a cement pump truck at a mixing temperature of 65℃ for 30 hours. This yielded a plugging material for the annulus of wells injecting liquid carbon dioxide. The plugging material has a water content of 0.03%, a salt content of 15 mg / L, a viscosity of 40 mPa·s at 60℃, a viscosity of 2000 mPa·s at 40℃, a viscosity of 12000 mPa·s at 20℃, a freezing point of 53℃, a flash point of 260℃, and a distillation temperature of 140℃.

[0032] Example 2

[0033] The only difference from Example 1 is that the sealing material is a mixture of C6-C60 mixed alkanes and asphalt. By weight percentage, the mixed alkanes include: 63 wt% C6-C36 alkanes, 30 wt% C37-C60 alkanes, and 7 wt% asphalt. The sealing material has a water content of 0.01%, a salt content of 12 mg / L, a viscosity of 35 mPa·s at 60°C, a viscosity of 2100 mPa·s at 40°C, a viscosity of 13000 mPa·s at 20°C, a freezing point of 52°C, a flash point of 270°C, and a distillation temperature of 135°C.

[0034] Example 3

[0035] The only difference from Example 1 is that, by weight percentage, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, C20, C21, C22, C23, C24, C25, C26, C27, C28, C29, C30, C31, C32, C33, C34, C35, and C36 alkanes each independently account for 0.8% to 4.5% of the total mass of the C6-C60 mixed alkanes and asphalt mixture. By weight percentage, C10 alkanes, C11 alkanes, C12 alkanes, C13 alkanes, C14 alkanes, C15 alkanes, C16 alkanes, C17 alkanes, C18 alkanes, C19 alkanes, C20 alkanes, C21 alkanes, C22 alkanes, C23 alkanes, C24 alkanes, C25 alkanes, C26 alkanes, C27 alkanes, C28 alkanes, C29 alkanes, C30 alkanes, C31 alkanes, C32 alkanes, C33 alkanes, and C34 alkanes each independently account for 1.7% to 2.3% of the total mass of the mixture of C6 to C60 alkanes and asphalt. The sealing material has a water content of 0.05%, a salt content of 19 mg / L, a viscosity of 32 mPa·s at 60℃, a viscosity of 2400 mPa·s at 40℃, a viscosity of 14000 mPa·s at 20℃, a freezing point of 52℃, a flash point of 260℃, and a distillation temperature of 140℃.

[0036] Example 4

[0037] The only difference from Example 1 is that the sealing material is a mixture of C6-C60 mixed alkanes and asphalt. By weight percentage, the mixed alkanes include: 65 wt% C6-C36 alkanes, 30 wt% C37-C60 alkanes, and 5 wt% asphalt. The sealing material has a water content of 0.04%, a salt content of 18 mg / L, a viscosity of 30 mPa·s at 60°C, a viscosity of 1600 mPa·s at 40°C, a viscosity of 10000 mPa·s at 20°C, a freezing point of 51°C, a flash point of 250°C, and a distillation temperature of 120°C.

[0038] Performance testing

[0039] First, carbon dioxide was stockpiled in advance. The carbon dioxide was at approximately -8°C and 2 MPa, and was in a liquid state. A cement pump truck was connected to the pipeline, and a skid-mounted pump pressurized the liquid carbon dioxide to 19 MPa, injecting it into the formation through the tubing at a rate of 3.5 t / h. After 3 hours, the casing pressure dropped to 0.7 MPa, and after 48 hours, it dropped to 0 MPa. Temperature and pressure gauges were used for testing. The wellbore temperature at different depths was tested. With increasing depth, the temperature continuously increased, reaching approximately 52°C (the solidification point of a mixture of C6-C60 alkanes and asphalt) at 2000 meters. This indicates that the sealing material has a superior sealing effect. Specific test results are shown in Table 1.

[0040] Table 1

[0041]

[0042] As can be seen from the above description, the embodiments of the present invention achieve the following technical effects:

[0043] The plugging material prepared using this invention, when applied to the annulus of a well injected with liquid carbon dioxide, shows a clear trend of increasing temperature at different depths. At 2000 meters, the temperature approaches the solidification point of a C6-C60 alkane-asphalt mixture. Furthermore, the casing pressure drops to 0 MPa 48 hours after liquid carbon dioxide injection. This plugging material is pollution-free, low-cost, and reusable. Compared to gas-tight packers and gas-tight tubing plugging, it can reduce investment by approximately 500,000 yuan per well. The preparation method of this plugging material is simple, cost-effective, suitable for large-scale production, and has broad prospects for industrial application.

[0044] While this specification contains numerous specific implementation details, these should not be construed as limiting the scope of any invention or the scope of the claims, but rather are primarily intended to describe features of specific embodiments of a particular invention. Certain features described in the various embodiments herein may also be implemented in combination in a single embodiment. Conversely, various features described in a single embodiment may also be implemented separately in various embodiments or in any suitable sub-combination. Furthermore, while features may function in certain combinations as described above and even initially claimed in this way, one or more features from a claimed combination may be removed from that combination in some cases, and a claimed combination may refer to a sub-combination or a variation thereof.

[0045] Similarly, although the operations are described in a specific order, this should not be construed as requiring these operations to be performed in the specific order shown or sequentially, or requiring all illustrated operations to be performed to achieve the desired result. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system modules and components in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0046] Thus, specific embodiments of the subject matter have been described. Other embodiments are within the scope of the appended claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve the desired result. Furthermore, the depicted processes are not necessarily in the specific order or sequential sequence shown to achieve the desired result. In some implementations, multitasking and parallel processing may be advantageous.

[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0048] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A sealing material for the annulus of a well injecting liquid carbon dioxide, characterized in that, The sealing material is a mixture of C6-C60 mixed alkanes and asphalt. By weight percentage, the mixed alkanes include: 60-65 wt% C6-C36 alkanes, 25-30 wt% C37-C60 alkanes, and 5-10 wt% of the asphalt.

2. The sealing material for the annulus of a well injecting liquid carbon dioxide, as described in claim 1, is characterized in that... Of the C6 to C36 alkanes, by weight percentage, C6 alkanes, C7 alkanes, C8 alkanes, C9 alkanes, C10 alkanes, C11 alkanes, C12 alkanes, C13 alkanes, C14 alkanes, C15 alkanes, C16 alkanes, C17 alkanes, C18 alkanes, C19 alkanes, C20 alkanes, C21 alkanes, C22 alkanes, C23 alkanes, C24 alkanes, C25 alkanes, C26 alkanes, C27 alkanes, C28 alkanes, C29 alkanes, C30 alkanes, C31 alkanes, C32 alkanes, C33 alkanes, C34 alkanes, C35 alkanes, and C36 alkanes each independently account for 0.7% to 4.5% of the total mass of the mixture of C6 to C60 alkanes and asphalt.

3. The sealing material for the annulus of a well injecting liquid carbon dioxide, as described in claim 1 or 2, is characterized in that... The sealing material has a freezing point of 52-55℃, a flash point of 200-300℃, and a distillation temperature of 120-160℃.

4. The sealing material for the annulus of a well injecting liquid carbon dioxide, as described in any one of claims 1 to 3, is characterized in that... The sealing material has a water content of 0-0.05% and a salt content of 0-20 mg / L.

5. The sealing material for the annulus of a well injecting liquid carbon dioxide, according to any one of claims 1 to 4, characterized in that, The viscosity of the sealing material is 30-60 mPa·s at 60°C, 1500-2500 mPa·s at 40°C, and 10000-15000 mPa·s at 20°C.

6. The sealing material for the annulus of a well injecting liquid carbon dioxide, as described in claim 2, is characterized in that... Of the C6 to C36 alkanes, by weight percentage, C10 alkanes, C11 alkanes, C12 alkanes, C13 alkanes, C14 alkanes, C15 alkanes, C16 alkanes, C17 alkanes, C18 alkanes, C19 alkanes, C20 alkanes, C21 alkanes, C22 alkanes, C23 alkanes, C24 alkanes, C25 alkanes, C26 alkanes, C27 alkanes, C28 alkanes, C29 alkanes, C30 alkanes, C31 alkanes, C32 alkanes, C33 alkanes, and C34 alkanes each independently account for 1.7 to 2.3% of the total mass of the mixture of the C6 to C60 mixed alkanes and asphalt.

7. A method for preparing a plugging material for the annulus of a well injected with liquid carbon dioxide according to any one of claims 1 to 6, characterized in that, The preparation method includes: taking 90-95% of C6-C60 alkanes for a first heating treatment, then taking 5-10% of asphalt for a second heating treatment, and mixing them in a vertical tank to obtain the sealing material for the annulus of wells used for injecting liquid carbon dioxide.

8. The method for preparing the plugging material for the annulus of a well injected with liquid carbon dioxide according to claim 7, characterized in that, The mixing process is carried out at a temperature of 60–70°C for 24–36 hours.

9. The method for preparing the plugging material for the annulus of a well injected with liquid carbon dioxide according to claim 7, characterized in that, The temperature of the first heating treatment is 60-70℃, and the treatment time is 8-12 hours; Preferably, the temperature of the secondary heating treatment is 80-90°C, and the treatment time is 4-6 hours.

10. A sealing material for the annulus of a well for liquid carbon dioxide injection according to any one of claims 1 to 6, or a sealing material obtained by the preparation method of the sealing material for the annulus of a well for liquid carbon dioxide injection according to any one of claims 7 to 9, for use in the fields of petroleum development, waterproofing and corrosion prevention, or cryogenic gas filling.

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