A carbon dioxide sequestration tool and method

Abstract

The application discloses a carbon dioxide burying tool and method, and relates to the technical field of carbon dioxide storage, wherein the carbon dioxide burying tool comprises a tubing, a packer and a ball seat assembly, one end of the tubing is provided with a one-way valve; the packer is arranged on the end of the tubing far away from the one-way valve; the ball seat assembly comprises a ball seat core, a connecting seat and a soluble ball; the connecting seat is connected with the tubing, the connecting seat is provided with a circulating hole, the circulating hole is communicated with the inside of the tubing and a burying well, the ball seat core is slidably connected with the connecting seat, and the ball seat core can shield the circulating hole; the soluble ball is abutted with the ball seat core, so that the tubing is formed with a one-way seal in the direction from the packer to the one-way valve. The technical scheme provided by the application solves the problem that the permanent packer cannot be recycled, and when the packer needs to be repaired or replaced in the later period, a drilling and grinding tool needs to be lowered to grind and mill the packer, time consumption is high, operation cost is high, and the grinding and milling operation can cause related wellbore casing damage, grinding and milling pipe string sticking and other problems.

Description

Technical Field

[0001] This invention relates to the field of carbon dioxide sequestration technology, and in particular to a carbon dioxide burial tool and method. Background Technology

[0002] Carbon dioxide is one of the major greenhouse gases and plays a crucial role in climate change. Sequestering carbon dioxide helps reduce its concentration in the atmosphere, thereby slowing the rate of global climate change. Currently, the main methods for handling carbon dioxide involve capturing, collecting, and safely storing carbon emissions from human activities in deep geological structures or deep-sea carbon pools. Many pilot experiments and downhole applications have been conducted in major oilfields both domestically and internationally, but the tool strings used are conventional production completion tool strings for oil and gas wells, consisting of a shear pump detachable ball seat, a landing sub, a permanent packer or overlift recovery packer, a circulating sleeve, and tubing.

[0003] Conventional tool strings use permanent packers to seal the annulus between the tubing and the well casing. Permanent packers provide excellent sealing, achieving a gas seal. However, because they are not recyclable, subsequent well workovers or packer replacements require milling with drilling tools, which is time-consuming and costly. Furthermore, milling operations can lead to risks such as well casing damage and stuck drill strings. Summary of the Invention

[0004] The main objective of this invention is to propose a carbon dioxide storage tool and method, which aims to solve the problems of permanent packers being non-recoverable and requiring drilling tools to be run down for milling when well repair or packer replacement is needed. This process is time-consuming and costly, and the milling operation can also cause problems such as well casing damage and stuck drill strings.

[0005] To achieve the above objectives, this invention proposes a carbon dioxide burial tool for use in carbon dioxide burial wells, comprising tubing, a packer, and a ball seat assembly. One end of the tubing is provided with a one-way valve. The packer is fitted onto the end of the tubing furthest from the one-way valve. The ball seat assembly includes a ball seat core, a connecting seat, and a soluble ball. The connecting seat is connected to the tubing and has a circulation hole that connects the interior of the tubing to the burial well. The ball seat core is slidably connected to the connecting seat and can block the circulation hole. The soluble ball is located at the end of the ball seat core furthest from the one-way valve and abuts against the ball seat core to create a one-way seal in the direction from the packer to the one-way valve.

[0006] In one embodiment, the connector has a stop portion located at one end of the connector near the one-way valve.

[0007] In one embodiment, the packer divides the space of the buried well into a top annulus and a bottom annulus. The top annulus is located at the end of the tubing away from the check valve, and the bottom annulus is located at the end of the tubing closer to the check valve, with the check valve located within the bottom annulus.

[0008] In one embodiment, the carbon dioxide burial tool further includes an anchoring seal plug that connects the packer and the tubing.

[0009] In one embodiment, the ball seat core has an annular structure, and the outer wall of the ball seat core is in sealed contact with the inner wall of the connecting seat.

[0010] In one embodiment, the diameter of the inner cavity of the ball seat core is smaller than the diameter of the soluble ball, and the soluble ball is capable of shielding and sealing the inner cavity of the ball seat core.

[0011] In one embodiment, the ball seat core has a limiting section located at one end of the ball seat core near the soluble ball, and the cross-sectional area of ​​the inner cavity of the limiting section gradually decreases along the direction from the soluble ball to the one-way valve.

[0012] In one embodiment, the wall of the circulation hole is inclined along the direction from the one-way valve to the ball seat core.

[0013] In one embodiment, the soluble ball is a soluble magnesium alloy ball.

[0014] This invention also proposes a carbon dioxide burial method, which is implemented using carbon dioxide burial tools and includes the following steps:

[0015] A protective fluid is injected into the annulus of the oil jacket; the protective fluid enters through the packer and fills the annulus of the oil jacket.

[0016] Protective fluid from the annulus enters the ball seat assembly and the oil pipe through the circulation hole;

[0017] When the protective fluid fills the oil pipe, the soluble ball is dropped into the oil pipe;

[0018] After the soluble ball contacts the ball seat core, pressure is applied to the oil pipe so that the soluble ball squeezes the ball seat core to slide, eventually blocking the circulation hole. At the same time, the packer is anchored to the inner wall of the burial under pressure.

[0019] After the soluble ball is dissolved by the protective fluid, carbon dioxide is injected into the oil pipe so that the carbon dioxide is buried underground through the one-way valve.

[0020] When the packer needs to be retrieved for well workover operations, the tubing can be separated from the packer by forward rotation or overlift shearing. The tubing is then removed, and a matching retrieval tool is lowered to the packer position. The packer is then lifted to release the seal and retrieved from the well.

[0021] This invention provides a carbon dioxide burial tool comprising three main parts: tubing, a packer, and a ball seat assembly. One end of the tubing is equipped with a one-way valve to control the unidirectional flow of carbon dioxide and prevent backflow. The packer is installed at the end of the tubing furthest from the one-way valve to isolate different pressure zones and ensure effective carbon dioxide storage. The ball seat assembly consists of a ball seat core, a connecting seat, and a soluble ball. The connecting seat is connected to the tubing and has a circulation hole to allow communication between the tubing interior and the burial well. The ball seat core is slidably connected to the connecting seat and can block the circulation hole. The soluble ball is located at the distal end of the ball seat core and abuts against it, forming a unidirectional seal from the packer to the one-way valve. This carbon dioxide burial tool design improves the efficiency and safety of carbon dioxide burial. The one-way valve ensures the unidirectional flow of carbon dioxide and prevents gas leakage. The packer effectively isolates pressure zones and prevents cross-contamination between different areas. The ball seat assembly is designed to allow for setting via soluble balls when needed, while the circulation port design allows for the replacement of the protective fluid before setting, reducing corrosion to downhole equipment. Furthermore, the use of soluble balls reduces the complexity of downhole operations, as they automatically dissolve within a set time, avoiding the physical removal required by traditional packers. The ball seat assembly design takes into account practical downhole operations, achieving effective sealing without sacrificing downhole equipment through the combined use of soluble balls and circulation ports, while also reducing operation time and costs. This design comprehensively considers ease of operation, cost-effectiveness, and environmental safety. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0023] Figure 1 A schematic diagram of a structure of an embodiment of the carbon dioxide burial tool provided by the present invention;

[0024] Figure 2 for Figure 1 A magnified view of a section at point A in the middle;

[0025] Figure 3A flowchart illustrating the steps of the carbon dioxide burial method provided by this invention.

[0026] Explanation of icon numbers:

[0027] 100. Carbon dioxide storage tool; 1. Oil pipe; 11. Check valve; 2. Packer; 3. Ball seat assembly; 31. Ball seat core; 32. Connecting seat; 33. Soluble ball; 32a. Circulation hole; 321. Stop section; 2a. Top oil sleeve annulus; 2b. Bottom oil sleeve annulus; 4. Anchoring seal plug; 311. Limiting section.

[0028] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0029] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0031] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0032] This invention proposes a carbon dioxide burial tool 100.

[0033] Please see Figure 1In one embodiment of the present invention, the carbon dioxide burial tool 100 includes an oil pipe 1, a packer 2, and a ball seat assembly 3. One end of the oil pipe 1 is provided with a one-way valve 11. The packer 2 is sleeved on the end of the oil pipe 1 away from the one-way valve 11. The ball seat assembly 3 includes a ball seat core 31, a connecting seat 32, and a soluble ball 33. The connecting seat 32 is connected to the oil pipe 1 and has a circulation hole 32a. The circulation hole 32a connects the interior of the oil pipe 1 with the burial well. The ball seat core 31 is slidably connected to the connecting seat 32 and can block the circulation hole 32a. The soluble ball 33 is located at the end of the ball seat core 31 away from the one-way valve 11 and abuts against the ball seat core 31 to form a one-way seal in the direction from the packer 2 to the one-way valve 11.

[0034] In this embodiment, tubing 1 serves as the primary conduit for delivering carbon dioxide to a designated downhole location. A one-way valve 11 is installed at one end of tubing 1. This valve is designed to allow carbon dioxide to be injected into the well from tubing 1 while preventing backflow, ensuring the one-way nature and safety of the injection process. A packer 2 is installed at the other end of tubing 1, away from the one-way valve 11. Its function is to create a seal in the annulus between tubing 1 and the well casing, preventing carbon dioxide leakage to the outside of the wellbore. It also isolates different pressure zones, ensuring the stability and reliability of the burial process. The main advantage of this design is improved safety and efficiency of carbon dioxide burial operations. The use of the one-way valve 11 effectively prevents gas backflow, reduces the risk of blowout, and ensures the safety of personnel and equipment. The packer 2 ensures effective isolation and burial of carbon dioxide, reducing the possibility of environmental pollution and improving burial efficiency because it allows for more precise control of the injection location and quantity of carbon dioxide.

[0035] It should be noted that the ball seat assembly 3 is a key component of the carbon dioxide burial tool 100, consisting of a ball seat core 31, a connecting seat 32, and a soluble ball 33. The connecting seat 32 is connected to the tubing 1 and has a circulation hole 32a, which allows fluid exchange between the tubing 1 and the burial well. The ball seat core 31 and the connecting seat 32 are connected by a sliding connection, allowing the ball seat core 31 to move along the connecting seat 32 as needed to block or open the circulation hole 32a. The soluble ball 33 is located at the distal end of the ball seat core 31 and abuts against it, ensuring a one-way seal in the direction from the packer 2 to the one-way valve 11. The design of the ball seat assembly 3 provides an effective one-way sealing mechanism, ensuring that the protective fluid can only flow unidirectionally from the annulus to the tubing 1, preventing leakage and backflow of the protective fluid and enhancing the safety of the protective fluid replacement process. The use of soluble ball 33 simplifies downhole operations because it automatically dissolves within a set time after setting, eliminating the need for additional recovery operations and thus reducing operational complexity and cost.

[0036] The present invention provides a carbon dioxide burial tool 100, comprising three main parts: a tubing 1, a packer 2, and a ball seat assembly 3. One end of the tubing 1 is equipped with a one-way valve 11 to control the unidirectional flow of carbon dioxide and prevent backflow. The packer 2 is installed at the other end of the tubing 1 away from the one-way valve 11 to isolate different pressure zones and ensure effective carbon dioxide burial. The ball seat assembly 3 consists of a ball seat core 31, a connecting seat 32, and a soluble ball 33. The connecting seat 32 is connected to the tubing 1 and has a circulation hole 32a, enabling communication between the inside of the tubing 1 and the burial well. The ball seat core 31 is slidably connected to the connecting seat 32 and can block the circulation hole 32a. The soluble ball 33 is located at the distal end of the ball seat core 31 and abuts against it, forming a unidirectional seal in the tubing 1 from the packer 2 to the one-way valve 11. This design of the carbon dioxide burial tool 100 improves the efficiency and safety of carbon dioxide burial. One-way valve 11 ensures unidirectional flow of carbon dioxide, preventing gas leakage. The packer 2 effectively isolates pressure zones, preventing cross-contamination between different areas. The ball seat assembly 3 is designed to allow setting via the soluble ball 33 when needed, while the circulation port 32a allows for the replacement of the protective fluid before setting, reducing corrosion to downhole equipment. Furthermore, the use of the soluble ball 33 reduces the complexity of downhole operations, as it automatically dissolves within a set time, avoiding the physical removal required by traditional packers 2. The ball seat assembly 3 is designed with practical downhole operations in mind, achieving effective sealing without sacrificing downhole equipment through the combined use of the soluble ball 33 and circulation port 32a, while also reducing operation time and costs. This design comprehensively considers ease of operation, cost-effectiveness, and environmental safety.

[0037] In one embodiment of the present invention, please refer to Figure 2 The connecting seat 32 has a stop portion 321, which is located at the end of the connecting seat 32 near the one-way valve 11.

[0038] In one embodiment, the connecting seat 32 is an important component of the ball seat assembly 3. It is connected to the tubing 1 and has a circulation hole 32a to achieve communication between the inside of the tubing 1 and the buried well. To ensure the stability of the ball seat core 31 during operation and limit its range of movement, the connecting seat 32 is specially designed with a stop 321. The stop 321 is generally a ring structure or a multi-segment boss structure surrounding the inside of the tubing 1, and the distance between its protruding ends is less than the inner diameter of the ball seat core 31, which can prevent the ball seat core 31 from sliding excessively. The stop 321 is located at the end of the connecting seat 32 near the one-way valve 11. When the ball seat core 31 moves along the connecting seat 32, the stop 321 can prevent the ball seat core 31 from moving excessively or accidentally falling off, ensuring that it always remains in the correct operating position. A stop 321 is provided at the end of the connecting seat 32 near the one-way valve 11, offering a mechanical positioning and protection mechanism to prevent the ball seat core 31 from shifting or falling off under high pressure or unexpected conditions, thus ensuring the stability and reliability of the entire ball seat assembly 3. This design reduces the potential risk of failure due to improper positioning of the ball seat core 31, improving the operational safety of the tool. Simultaneously, the presence of the stop 321 simplifies downhole operations, as operators can rely on this structural feature to quickly and accurately position the ball seat core 31, improving operational efficiency.

[0039] In one embodiment of the present invention, please refer to Figure 1 Packer 2 divides the space of the buried well into a top annulus 2a and a bottom annulus 2b. The top annulus 2a is located at the end of tubing 1 away from the check valve 11, and the bottom annulus 2b is located at the end of tubing 1 close to the check valve 11, with the check valve 11 located inside the bottom annulus 2b.

[0040] In this embodiment, the packer 2 divides the space of the burial well into two independent annular regions. The top annular region 2a is located at the upper part of the tubing 1, away from the one-way valve 11, while the bottom annular region 2b is located at the lower part of the tubing 1, close to the one-way valve 11. When the operator injects carbon dioxide into the tubing 1, the packer 2 anchors and seals against the well wall due to the pressure inside the tubing 1, isolating the top annular region 2a and the bottom annular region 2b into two independent cavities. The one-way valve 11 is placed in the bottom annular region 2b. This layout allows carbon dioxide to be injected from the upper part of the tubing 1, flowing downwards through the top annular region 2a to the bottom annular region 2b, where the one-way valve 11 ensures that the carbon dioxide can only flow in one direction, preventing backflow. The main advantage of this design is improved safety and efficiency of carbon dioxide burial. The packer 2 ensures the directional flow of carbon dioxide downhole, preventing carbon dioxide leakage into different areas and reducing the risk of gas leakage. By placing the one-way valve 11 within the bottom annulus 2b, the flow direction of carbon dioxide can be controlled more effectively, ensuring that gas does not flow back into the upper region of the tubing 1. This arrangement also facilitates downhole pressure control and gas recovery when needed, as the one-way valve 11 can respond quickly to pressure changes, preventing dangerous situations such as blowouts. Furthermore, this design simplifies downhole operations and reduces maintenance and workover costs, as the packer 2 can more precisely control pressure in different areas, reducing reliance on complex downhole equipment.

[0041] In one embodiment of the present invention, please refer to Figure 1 The carbon dioxide storage tool 100 also includes an anchoring seal plug 4, which connects the packer 2 and the tubing 1.

[0042] In one embodiment, the anchoring seal plug 4 is a key component that securely connects the packer 2 to the tubing 1, ensuring the packer 2's correct position and stability downhole. The anchoring seal plug 4 connects to the upper sealing sleeve of the packer 2 via threads, snap-fit, or other mechanical connections, while its other end connects to the tubing 1. This connection method allows the anchoring seal plug 4 to provide a seal between the tubing 1 and the packer 2, preventing carbon dioxide leakage and ensuring the stability and reliability of the packer 2 under high-pressure environments. The use of the anchoring seal plug 4 offers several significant advantages. First, it strengthens the connection between the packer 2 and the tubing 1, ensuring that the packer 2 will not shift or detach during high-pressure carbon dioxide injection, thereby improving operational safety. Second, the sealing performance provided by the anchoring seal plug 4 helps prevent gas leakage, reducing the risk of environmental pollution, and also improves carbon dioxide burial efficiency. Furthermore, the design of the anchoring seal plug 4 allows for easy retrieval or replacement of the packer 2 when well workover or packer 2 replacement is required, without the need for complex drilling operations, thereby reducing maintenance costs and operation time. This design improves the operational flexibility and long-term reliability of the entire CO2 burial tool 100.

[0043] In one embodiment of the present invention, please refer to Figure 1 The ball seat core 31 has a ring structure, and the outer wall of the ball seat core 31 is in sealed contact with the inner wall of the connecting seat 32.

[0044] In this embodiment, the ball seat core 31 is designed with a ring-shaped structure, which allows it to completely conform to the inner wall of the connecting seat 32. The outer wall of the ball seat core 31 is made of sealing material and is designed with a specific sealing lip or sealing surface to ensure a tight seal between it and the inner wall of the connecting seat 32. The ball seat core 31 is slidably connected to the connecting seat 32 via a guide rail or other sliding mechanism, ensuring that it does not shift during operation and thus maintaining a sealed contact with the inner wall of the tubing 1. The ring-shaped structure design of the ball seat core 31 provides several significant advantages. First, it enhances the sealing performance between the ball seat core 31 and the connecting seat 32, effectively preventing leakage of carbon dioxide or other fluids between the connecting seat 32 and the wellbore, thereby improving the safety and environmental friendliness of the burial operation. Second, due to the sealed contact between the ball seat core 31 and the inner wall of the connecting seat 32, it can withstand the operational requirements of a high-pressure environment, reducing the risk of failure due to poor sealing. Furthermore, the annular ball seat core 31 provides better stability and reliability during operation because it can evenly distribute pressure and reduce local stress concentration. This design also simplifies the installation and maintenance process, as the ball seat core 31 can more easily slide along the connecting seat 32 to block the circulation hole 32a, thereby enabling control of fluid flow. Overall, this design improves the performance and service life of the entire carbon dioxide burial tool 100.

[0045] In one embodiment of the present invention, please refer to Figure 2 The diameter of the inner cavity of the ball seat core 31 is smaller than the diameter of the soluble ball 33, and the soluble ball 33 can shield and seal the inner cavity of the ball seat core 31.

[0046] In one embodiment, the ball seat core 31 is designed with an inner cavity whose inner diameter is smaller than the diameter of the soluble ball 33. This design ensures that the soluble ball 33 can tightly abut against the inner cavity of the ball seat core 31 when placed, and due to the size difference, the soluble ball 33 cannot slide freely within the inner cavity, thus completely blocking and sealing the inner cavity of the ball seat core 31. In actual operation, the soluble ball 33 is placed in the inner cavity of the ball seat core 31, and its larger diameter forms a seal between the ball and the inner wall of the ball seat core 31, preventing the protective fluid from flowing through the inner cavity of the ball seat core 31. The main advantage of this design is that it provides a reliable sealing mechanism. Because the diameter of the soluble ball 33 is larger than the diameter of the inner cavity of the ball seat core 31, the soluble ball 33 forms a physical barrier within the inner cavity, effectively preventing the passage of the protective fluid and enhancing the sealing performance of the entire system.

[0047] In one embodiment of the present invention, please refer to Figure 2The ball seat core 31 has a limiting section 311, which is located at one end of the ball seat core 31 near the soluble ball 33. The cross-sectional area of ​​the inner cavity of the limiting section 311 gradually decreases along the direction from the soluble ball 33 to the one-way valve 11.

[0048] In this embodiment, the ball seat core 31 is designed with a limiting section 311, which is specifically located at the end of the ball seat core 31 near the soluble ball 33. The inner cavity of the limiting section 311 has a specific geometry, with its cross-sectional area gradually decreasing from the soluble ball 33 end to the one-way valve 11 end, forming a conical or tapered channel. This design allows the soluble ball 33 to be stably positioned within the inner cavity of the ball seat core 31, and as the pressure inside the oil pipe 1 increases, the contact between the soluble ball 33 and the limiting section 311 becomes tighter. The design of the limiting section 311 brings several significant advantages. First, it provides a stable positioning mechanism for the soluble ball 33, ensuring that the soluble ball 33 will not move within the inner cavity of the ball seat core 31 due to pressure changes, thus enhancing the stability and reliability of the entire system. Secondly, the gradually decreasing cross-sectional area of ​​the limiting section 311 facilitates pressure control, especially as fluid flows from the inside of the tubing 1 into the storage well. This design acts as a flow control device, helping to regulate fluid velocity and pressure. Furthermore, this design improves the sealing of fluid flow, as the gradually decreasing cross-sectional area more effectively seals the fluid flow path, reducing the likelihood of leakage. Overall, the design of the limiting section 311 improves the operational efficiency and safety of the carbon dioxide storage tool 100, while reducing maintenance costs and potential environmental risks.

[0049] In one embodiment of the present invention, please refer to Figure 2 The wall of the circulation hole 32a is inclined along the direction from the one-way valve 11 to the ball seat core 31.

[0050] In one embodiment, the circulation hole 32a is a through hole opened on the connecting seat 32, designed with a special inclined hole wall. This inclined design means that the hole wall of the circulation hole 32a is not perpendicular to the axis of the tubing 1, but gradually slopes from the one-way valve 11 end to the ball seat core 31 end. This structure allows fluid to flow along the inclined hole wall as it passes through the circulation hole 32a, thereby achieving a guided fluid exchange between the buried well and the interior of the tubing 1. This inclined design also helps guide fluid flow and reduce the circulation resistance of the protective fluid. The inclined hole wall helps optimize fluid dynamics, reducing turbulence and eddies as the fluid passes through the circulation hole 32a, thereby reducing fluid erosion and wear on downhole equipment. The inclined hole wall can serve as a pressure relief channel, helping to gradually release pressure when the pressure inside the tubing 1 is too high, reducing the risk of downhole pressure surges. The inclined design helps reduce the risk of blockage of the circulation hole 32a because the inclined hole wall can guide solid particles to move along the inclined direction, reducing deposition at the orifice.

[0051] In one embodiment of the present invention, please refer to Figure 1 Soluble sphere 33 is a soluble magnesium alloy sphere.

[0052] In this embodiment, the soluble ball 33 is made of soluble magnesium alloy material and is spherical in shape. This material can gradually dissolve under specific conditions (such as a specific chemical environment or after a certain period of time). During implementation, the soluble magnesium alloy ball is placed in the inner cavity of the ball seat core 31, wherein the inner diameter of the ball seat core 31 is designed to be smaller than the diameter of the soluble ball 33 to ensure that the soluble ball 33 can form a seal in the inner cavity. In actual operation, before carbon dioxide filling, a protective fluid must be filled into the annulus 2a and the tubing 1 to protect the tubing 1. First, the protective fluid is injected into the top annulus 2a, flowing into the bottom annulus 2b, and then through the circulation hole 32a into the connecting seat 32 and the tubing 1. After the top annulus 2a, bottom annulus 2b, and tubing 1 are completely filled with protective fluid, a soluble ball 33 is added. When the soluble ball 33 sinks onto the ball seat core 31, carbon dioxide is injected into the tubing 1 to increase the pressure. Under pressure, the soluble ball 33 pushes the ball seat core 31 to block the circulation hole 32a. At this point, the tubing 1 is sealed, and the soluble ball 33 dissolves under the action of the protective fluid. After dissolution, carbon dioxide can be deposited. It should be noted that the protective fluid is generally a mixture of water, desulfurizer, deoxygenator, bactericide, and NaOH (the annulus protective fluid generally has a pH ≥ 9.5). The solubility of soluble balls 33 eliminates the complex operation of physically removing or recovering packer components 2, simplifying downhole operations and reducing operating costs. Since soluble balls 33 do not require recovery after dissolution, downhole equipment maintenance is reduced, lowering long-term operating costs.

[0053] This invention also proposes a method for carbon dioxide burial; please refer to [link / reference]. Figure 3 The carbon dioxide burial method is implemented using a carbon dioxide burial tool 100. The specific structure of the carbon dioxide burial tool 100 is as described in the above embodiments. Since this carbon dioxide burial method adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described in detail here. The carbon dioxide burial method includes the following steps: injecting protective fluid into the annulus of the casing and tubing; the protective fluid enters and fills the annulus through the packer 2; the protective fluid from the annulus enters the ball seat assembly 3 and tubing 1 through the circulation hole 32a; when the protective fluid fills the tubing 1, a soluble ball 33 is inserted into the tubing 1; after the soluble ball 33 contacts the ball seat core 31, pressure is applied to the tubing 1 so that the soluble ball 33 squeezes the ball seat core 31 to slide, ultimately blocking the circulation hole 32a, while the packer 2 is anchored to the burial inner wall under pressure; after the soluble ball 33 is dissolved by the protective fluid, carbon dioxide is injected into the tubing 1 so that the carbon dioxide is buried underground through the one-way valve 11; when it is necessary to retrieve the packer 2 for well workover operations, the tubing 1 can be separated from the packer 2 by forward rotation or over-lift shearing, the tubing 1 is taken out, and then the matching retrieval tool is lowered to the position of the packer 2, and the packer 2 is pulled up to unseal and retrieved out of the well.

[0054] In this embodiment, the carbon dioxide burial method utilizes a specific carbon dioxide burial tool 100, which includes key components such as tubing 1, a one-way valve 11, a packer 2, and a ball seat assembly 3. First, a protective fluid is injected into the annulus. This fluid enters and fills the annulus through the packer 2, and then flows into the ball seat assembly 3 and the tubing 1 through the circulation hole 32a. After the tubing 1 is filled with the protective fluid, a soluble ball 33 is inserted into it. When the soluble ball 33 contacts and is compressed against the ball seat core 31, the core 31 slides and blocks the circulation hole 32a, while the packer 2 is anchored to the wellbore. As the soluble ball 33 dissolves in the protective fluid, carbon dioxide is injected into the tubing 1. The carbon dioxide flows unidirectionally through the one-way valve 11 and is buried underground. If well workover is required, the tubing 1 can be detached from the packer 2 by forward rotation or overlift shearing, the tubing 1 can be removed, and the packer 2 can be retrieved using the appropriate tools. This carbon dioxide burial method has multiple advantages. First, by using a protective fluid and soluble balls 33, effective protection of the tubing 1 and wellbore is achieved, preventing problems such as pipe corrosion and leakage. Second, the anchoring function of the packer 2 ensures the stability of the annulus, preventing potential risks caused by pressure instability. Furthermore, the self-dissolving properties of the soluble balls 33 simplify the packing process, reducing the complexity and cost of downhole operations. The use of a one-way valve 11 ensures unidirectional flow of carbon dioxide, preventing backflow. Finally, the recyclable design of the packer 2 improves tool reusability, reduces long-term operating costs, and minimizes the environmental impact of downhole operations. Overall, this method improves the efficiency, safety, and economy of carbon dioxide burial while reducing potential environmental risks.

[0055] The above are merely exemplary embodiments of the present invention and do not limit the scope of the patent of the present invention. All equivalent structural transformations made using the contents of the present invention specification and drawings under the technical concept of the present invention, or direct / indirect applications in other related technical fields, are included within the scope of patent protection of the present invention.

Claims

1. A carbon dioxide burial tool, applied to a carbon dioxide burial well, characterized in that, include: Oil pipe (1), one end of which is provided with a one-way valve (11); Packer (2), said packer (2) being fitted onto the end of the oil pipe (1) away from the check valve (11); and Ball seat assembly (3), the ball seat assembly (3) includes a ball seat core (31), a connecting seat (32) and a soluble ball (33); The connecting seat (32) is connected to the oil pipe (1). The connecting seat (32) has a circulation hole (32a) that connects the interior of the oil pipe (1) to the well. The ball seat core (31) is slidably connected to the connecting seat (32) and can block the circulation hole (32a). The soluble ball (33) is located at the end of the ball seat core (31) away from the one-way valve (11). The soluble ball (33) abuts against the ball seat core (31) so that the oil pipe (1) forms a one-way seal in the direction from the packer (2) to the one-way valve (11).

2. The carbon dioxide burial tool as described in claim 1, characterized in that, The connecting seat (32) has a stop portion (321) located at one end of the connecting seat (32) near the one-way valve (11).

3. The carbon dioxide burial tool as described in claim 2, characterized in that, The packer (2) divides the space of the buried well into a top annulus (2a) and a bottom annulus (2b). The top annulus (2a) is located at the end of the tubing (1) away from the check valve (11), and the bottom annulus (2b) is located at the end of the tubing (1) close to the check valve (11), with the check valve (11) located inside the bottom annulus (2b).

4. The carbon dioxide burial tool as described in claim 3, characterized in that, The carbon dioxide burial tool also includes an anchoring seal plug (4), which connects the packer (2) and the tubing (1).

5. The carbon dioxide burial tool as described in any one of claims 1 to 4, characterized in that, The ball seat core (31) has an annular structure, and the outer wall of the ball seat core (31) is in sealed contact with the inner wall of the connecting seat (32).

6. The carbon dioxide burial tool as described in claim 5, characterized in that, The diameter of the inner cavity of the ball seat core (31) is smaller than the diameter of the soluble ball (33), and the soluble ball (33) can shield and seal the inner cavity of the ball seat core (31).

7. The carbon dioxide burial tool as described in claim 6, characterized in that, The ball seat core (31) has a limiting section (311) located at one end of the ball seat core (31) near the soluble ball (33), and the cross-sectional area of ​​the inner cavity of the limiting section (311) gradually decreases along the direction from the soluble ball (33) to the one-way valve (11).

8. The carbon dioxide burial tool as described in claim 7, characterized in that, The wall of the circulation hole (32a) is inclined along the direction from the one-way valve (11) to the ball seat core (31).

9. The carbon dioxide burial tool as described in any one of claims 1 to 4, characterized in that, The soluble ball (33) is a soluble magnesium alloy ball.

10. A method for storing carbon dioxide, implemented using the carbon dioxide storage tool as described in any one of claims 1 to 9, characterized in that, Includes the following steps: A protective fluid is injected into the annulus of the oil jacket. The protective fluid enters and fills the annulus of the oil jacket through the packer (2). The protective fluid from the annulus enters the ball seat assembly (3) and the oil pipe (1) through the circulation hole (32a); When the protective fluid fills the oil pipe (1), the soluble ball (33) is put into the oil pipe (1); After the soluble ball (33) comes into contact with the ball seat core (31), pressure is applied to the oil pipe (1) so that the soluble ball (33) squeezes the ball seat core (31) to slide, and finally blocks the circulation hole (32a). At the same time, the packer (2) is anchored to the buried inner wall under pressure. After the soluble ball (33) is dissolved by the protective liquid, carbon dioxide is injected into the oil pipe (1) so that the carbon dioxide is buried underground through the one-way valve (11); When it is necessary to retrieve the packer (2) for well workover, the tubing (1) can be separated from the packer (2) by forward rotation or overlift shearing. The tubing (1) is then removed, and a matching retrieval tool is lowered to the position of the packer (2). The packer (2) is then lifted up to unseal and retrieved from the well.

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