Carbon dioxide sequestration system and method for underwater abandoned well

Abstract

The application provides a carbon dioxide storage system and method for an underwater abandoned well, and relates to the technical field of carbon capture and storage. The carbon dioxide storage system comprises a floating platform and a carbon dioxide storage device. The floating platform is used for floating on the water surface. The carbon dioxide storage device is arranged on the floating platform. The carbon dioxide storage device comprises a gas storage tank, a gas conveying pipe and a docking head which are sequentially connected. The gas storage tank can store captured carbon dioxide. The docking head can be docked with the wellhead of the underwater abandoned well. The gas conveying pipe can convey the carbon dioxide in the gas storage tank to the abandoned well for storage after the docking head is docked with the wellhead. Based on this, the application realizes the organic combination of the underwater abandoned well and the carbon dioxide storage, achieves the integration of marine oil exploration and carbon dioxide storage, can not only reduce the emission of carbon dioxide and promote the development of the environmental protection industry, but also can improve the utilization rate of the underwater abandoned well and reduce the environmental burden of the marine oil industry.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of carbon capture and storage, and particularly relates to a carbon dioxide storage system and method for underwater abandoned well. BACKGROUND

[0002] In recent years, with the exhaustion of marine oil resources all over the world, almost every country with the ability of marine oil exploration is actively exploring marine oil. In the related art, when marine oil is explored, a plurality of exploration wells are drilled on the seabed of a certain exploration position to explore whether marine oil exists in the exploration position through the exploration wells. If it is finally explored that there is no marine oil in the exploration position, the drilled exploration wells will be abandoned, which become abandoned wells. The abandoned wells cannot be effectively utilized, thereby increasing the environmental burden of the marine oil industry. SUMMARY

[0003] The present application provides a carbon dioxide storage system and method for underwater abandoned well, aiming at solving the problem that abandoned wells left by marine oil exploration cannot be effectively utilized in the related art.

[0004] In order to solve the above-mentioned drawbacks existing in the related art, the present application provides a carbon dioxide storage system for underwater abandoned well in the first aspect, comprising a floating platform and a carbon dioxide storage device. The floating platform is used for floating on the water surface. The carbon dioxide storage device is arranged on the floating platform. The carbon dioxide storage device comprises a gas storage tank, a gas conveying pipe and a butt joint having a containing cavity. The butt joint further has opposite connecting end and receiving end. The receiving end is provided with a receiving opening in communication with the containing cavity. The connecting end is provided with a socket in communication with the containing cavity. The gas conveying pipe has opposite gas inlet end and gas outlet end. The gas inlet end is communicated with the gas storage tank. The gas outlet end is inserted into the containing cavity through the socket. The gas storage tank is used for storing carbon dioxide to be stored. The butt joint is used for receiving the wellhead of the underwater abandoned well in the containing cavity through the receiving opening when the wellhead is butted, and making the receiving end abut on the ground around the wellhead. The gas inlet end is used for leading the carbon dioxide to be stored in the gas storage tank. The gas outlet end is used for inserting the abandoned well through the wellhead after the butt joint is butted with the wellhead, so as to lead the carbon dioxide to be stored into the abandoned well.

[0005] In some implementation schemes, the carbon dioxide storage device further comprises a spray head arranged on the gas outlet end and communicated with the gas conveying pipe, and used for spraying the carbon dioxide to be stored conveyed by the gas conveying pipe into the abandoned well after the gas outlet end is inserted into the abandoned well through the wellhead.

[0006] In some implementations, the carbon dioxide storage device further comprises a water pipe, a water tank and a water pump, which are all arranged on the floating platform, one end of the water pipe is communicated with the gas pipe, and the other end of the water pipe is communicated with the water tank through the water pump; the water pump is used to pump the water in the accommodation cavity into the water tank through the nozzle, the gas pipe and the water pipe after the connector is connected with the wellhead, so that a pressure difference is formed between the inside and outside of the connector, and the connector is pressed on the ground around the wellhead by the pressure difference.

[0007] In some implementations, the accommodation cavity comprises an upper accommodation cavity, a middle accommodation cavity and a lower accommodation cavity, the upper accommodation cavity, the middle accommodation cavity and the lower accommodation cavity are sequentially arranged and spaced apart along a direction from the connecting end to the receiving end, the spigot is communicated with the upper accommodation cavity, the exhaust end is inserted into the upper accommodation cavity through the spigot, the middle accommodation cavity is communicated with the upper accommodation cavity through the upper through hole, the middle accommodation cavity is communicated with the lower accommodation cavity through the lower through hole, and the receiving port is communicated with the lower accommodation cavity; the connector is specifically used to accommodate the wellhead in the lower accommodation cavity through the receiving port and align the wellhead with the lower through hole when the wellhead is connected. Further, the nozzle is a self-feeding nozzle, and the carbon dioxide storage device further comprises a buffer guide, the buffer guide has a through hole penetrating from one end to the other end, the buffer guide is arranged in the middle accommodation cavity, one end of the buffer guide abuts against an inner wall of the middle accommodation cavity provided with the upper through hole, and the other end of the buffer guide abuts against an inner wall of the middle accommodation cavity provided with the lower through hole, the two openings of the through hole are respectively aligned with and connected to the upper through hole and the lower through hole, and the through hole is used to communicate the upper accommodation cavity with the lower accommodation cavity; the self-feeding nozzle is used to spray the carbon dioxide to be stored conveyed by the gas pipe outward after the connector is connected with the wellhead, so that the self-feeding nozzle enters the lower accommodation cavity through the through hole by the reaction force generated during spraying, and is inserted into the abandoned well through the wellhead, so that the carbon dioxide to be stored conveyed by the gas pipe is sprayed into the abandoned well.

[0008] In some implementations, the buffer guide comprises a main body, a connecting column and a plug, one end of the connecting column is arranged on one end of the main body, and the plug is arranged on the other end of the connecting column, the main body is arranged in the middle accommodation cavity, the connecting column is arranged in the upper through hole, and the plug is arranged in the upper accommodation cavity, one end of the main body provided with the connecting column abuts against an inner wall of the middle accommodation cavity provided with the upper through hole, the other end of the main body not provided with the connecting column abuts against an inner wall of the middle accommodation cavity provided with the lower through hole, a side wall of the connecting column abuts against a hole wall of the upper through hole, and the plug close to the main body abuts against an inner wall of the upper accommodation cavity provided with the upper through hole, the two openings of the through hole are respectively located on the other end of the plug away from the main body and the other end of the main body not provided with the connecting column.

[0009] In some implementations, the carbon dioxide storage device further comprises a sealing ring, which is located between the one end of the main body provided with the connecting column and the inner wall of the middle accommodation cavity provided with the upper through hole and surrounds the connecting column.

[0010] In some implementations, the carbon dioxide storage device further comprises at least one buffer spring located between the one end of the main body provided with the connecting column and the inner wall of the middle accommodating cavity provided with the upper through hole, and abutting against the one end of the main body provided with the connecting column and the inner wall of the middle accommodating cavity provided with the upper through hole respectively.

[0011] In some implementations, the thickness of the adapter gradually decreases along a direction from the receiving end to the connecting end, and the shape of the accommodating cavity matches the shape of the adapter.

[0012] In some implementations, the floating platform comprises a ship.

[0013] The second aspect of the present application provides a carbon dioxide storage method for an abandoned well under water, which is applied to the carbon dioxide storage system mentioned in the first aspect of the present application, and comprises the following steps: inserting an adapter and a gas conveying pipe provided with one end in the adapter into water under water; docking the adapter with a wellhead of an abandoned well under water, so as to accommodate the wellhead in the adapter through the receiving opening of the adapter, and abut the end of the adapter provided with the receiving opening against the ground around the wellhead; inserting the one end of the gas conveying pipe provided with in the adapter into the abandoned well through the wellhead; and conveying the carbon dioxide to be stored into the abandoned well by using the gas conveying pipe.

[0014] For the carbon dioxide storage system provided by the present application, it comprises a floating platform for floating on the water surface and a carbon dioxide storage device arranged on the floating platform, and the carbon dioxide storage device is composed of a gas conveying pipe, a gas storage tank for storing carbon dioxide, and an adapter with an accommodating cavity. The adapter has opposite connecting end and receiving end, the receiving end is provided with a receiving opening in communication with the accommodating cavity, and the connecting end is provided with an insertion opening in communication with the accommodating cavity. The gas conveying pipe has opposite gas inlet end and gas outlet end, the gas inlet end is communicated with the gas storage tank, and the gas outlet end is inserted into the accommodating cavity through the insertion opening. When the adapter is docked with the wellhead of the abandoned well under water, the wellhead is accommodated in the accommodating cavity through the receiving opening, and the receiving end is abutted against the ground around the wellhead. The gas inlet end is used to lead the carbon dioxide in the gas storage tank out. The gas outlet end is used to insert into the abandoned well through the wellhead after the adapter is docked with the wellhead, so as to lead the carbon dioxide into the abandoned well. As can be seen, the present application can convey the carbon dioxide into the abandoned well under water for storage, realize the organic combination of the abandoned well under water and the carbon dioxide storage, achieve the integration of offshore oil exploration and carbon dioxide storage, not only can reduce the emission of carbon dioxide and promote the development of environmental protection industry, but also can improve the utilization rate of the abandoned well under water and reduce the environmental burden of the offshore oil industry.

[0015] For the carbon dioxide storage method provided by the present application, it is applied in the carbon dioxide storage system provided by the present application, that is, it is realized based on the carbon dioxide storage system provided by the present application, and therefore it has all the advantages of the carbon dioxide storage system provided by the present application. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the related art or the embodiments of the present application, the drawings needed to be used in the description of the related art or the embodiments of the present application will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the present application, and not all embodiments. Those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

[0017] Figure 1 A structural schematic diagram of a carbon dioxide storage system provided by an embodiment of the present application is shown in the figure.

[0018] Figure 2 A sectional view of a joint provided by an embodiment of the present application is shown in the figure.

[0019] Figure 3 A flowchart of a carbon dioxide storage method provided by an embodiment of the present application is shown in the figure.

[0020] The marks in each of the above figures respectively represent:

[0021] 100-floating platform, 200-carbon dioxide storage device, 210-gas storage tank, 220-gas delivery pipe, 230-joint, 231-receiving opening, 232-plug opening, 240-nozzle, 250-buffering guide, 251-main body, 252-connection column, 253-plug, 260-sealing ring. DETAILED DESCRIPTION

[0022] In the related art, when marine oil exploration is performed, a plurality of exploratory wells are drilled on the seabed at a certain exploration location to explore whether marine oil exists at the exploration location through the exploratory wells. If it is finally explored that no marine oil exists at the exploration location, the drilled exploratory wells will be abandoned, which become abandoned wells. The abandoned wells cannot be effectively utilized, thereby increasing the environmental burden of the marine oil industry. In view of this, the present application proposes a carbon dioxide storage system for underwater abandoned wells and a corresponding carbon dioxide storage method in the embodiments below, which can store carbon dioxide in underwater abandoned wells, realizes the organic combination of underwater abandoned wells and carbon dioxide storage, achieves the integration of marine oil exploration and carbon dioxide storage, not only can reduce the emission of carbon dioxide and promote the development of environmental protection, but also can improve the utilization rate of underwater abandoned wells and reduce the environmental burden of the marine oil industry, thereby avoiding the above-mentioned drawbacks existing in the related art.

[0023] In order to make the purposes, technical solutions and advantages of the present application more obvious and easy to understand, the present application will be described clearly and completely below in conjunction with the embodiments of the present application and corresponding drawings, wherein the same or similar reference signs represent the same or similar elements or elements having the same or similar functions throughout. It should be understood that the embodiments of the present application described below are only used to explain the present application and do not limit the present application, that is, all other embodiments obtained by those skilled in the art without creative labor on the basis of various embodiments of the present application belong to the scope of protection of the present application. In addition, the technical features involved in the various embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0024] Please refer to Figure 1 , Figure 1 is a structural schematic diagram of a carbon dioxide storage system. The present embodiment provides a carbon dioxide storage system for an underwater abandoned well, which comprises a floating platform 100 and a carbon dioxide storage device 200, the floating platform 100 is used to float on the water surface, the carbon dioxide storage device 200 is arranged on the floating platform 100, the carbon dioxide storage device 200 comprises a gas storage tank 210, a gas conveying pipe 220 and a docking head 230 having a containing cavity (not shown in the figure), the docking head 230 also has opposite connecting ends and a receiving end, the receiving end is provided with a receiving opening 231 which is in communication with the containing cavity, and the connecting end is provided with an insertion opening 232 which is in communication with the containing cavity, the gas conveying pipe 220 has opposite gas inlet and outlet ends, the gas inlet end is communicated with the gas storage tank 210, and the gas outlet end is inserted into the containing cavity through the insertion opening 232 and is limited in the containing cavity.

[0025] Specifically, the gas storage tank 210 is used to store the carbon dioxide to be stored; the docking head 230 is used to receive the wellhead in the containing cavity through the receiving opening 231 when the docking head 230 is docked with the wellhead of the underwater abandoned well, and to make the receiving end of the docking head 230 abut on the ground (i.e. the seabed) around the wellhead to surround the wellhead; the gas inlet end of the gas conveying pipe 220 is used to lead out the carbon dioxide to be stored in the gas storage tank 210; and the gas outlet end of the gas conveying pipe 220 is used to insert into the abandoned well through the wellhead after the docking head 230 is docked with the wellhead, so as to lead the carbon dioxide to be stored into the abandoned well. That is, the gas storage tank 210 can store the carbon dioxide to be stored, the docking head 230 can be docked with the wellhead of the underwater abandoned well, and the gas conveying pipe 220 can transport the carbon dioxide to be stored in the gas storage tank 210 into the abandoned well for storage after the docking head 230 is docked with the wellhead.

[0026] In the embodiment, the floating platform 100 can be a truss structure (such as a deep sea floating platform) which is above the water surface and has a water surface platform, or can be a ship (such as a deep water floating ship), and the specific configuration can be set according to actual needs, which is not uniquely limited in the present application; however, in order to improve the mobility of the carbon dioxide storage system and facilitate its movement between different abandoned wells, the floating platform 100 is preferably a ship. The carbon dioxide stored in the gas storage tank 210 is not only limited to carbon dioxide captured on land, but also includes carbon dioxide in exhaust gas emitted by the ship, and the specific configuration can be set according to actual needs, which is not uniquely limited in the present application. The gas delivery pipe 220 can be a hose or a hard pipe, and the delivery of the carbon dioxide to be stored in the gas storage tank 210 can depend on equipment with exhaust function such as a fan, or can depend on the gravity of the carbon dioxide to be stored, and the specific configuration can be set according to actual needs, which is not uniquely limited in the present application. Preferably, when the delivery of the carbon dioxide to be stored in the gas storage tank 210 by the gas delivery pipe 220 depends on the gravity of the carbon dioxide to be stored, energy can be effectively saved, and at this time the gas storage tank 210 is a low-temperature gas storage tank, and the carbon dioxide to be stored in the gas storage tank 210 is low-temperature supercritical carbon dioxide.

[0027] As can be seen from the above, the embodiment can deliver carbon dioxide to the abandoned well under the water for storage, realize the organic combination of the abandoned well under the water and the carbon dioxide storage, achieve the integration of marine oil exploration and carbon dioxide storage, not only can reduce the emission of carbon dioxide and promote the development of environmental protection, but also can improve the utilization rate of the abandoned well under the water and reduce the environmental burden of the marine oil industry. Moreover, the entire underwater part of the carbon dioxide storage system (i.e. the gas delivery pipe 220 and the docking head 230) does not contain any electrical equipment, is easy to maintain, has good safety, has strong applicability, and can also obtain good stability. In addition, it is also very convenient to extract the carbon dioxide stored in the abandoned well when realizing the related use of carbon dioxide in the future.

[0028] In some embodiments, please refer to Figure 2 , Figure 2 is a sectional view of the docking head, the carbon dioxide storage device 200 further includes a spray head 240 in addition to the structure given in the foregoing, the spray head 240 is located in the accommodating cavity of the docking head 230, and the spray head 240 is arranged on the exhaust end of the gas delivery pipe 220 and communicates with the gas delivery pipe 220. Specifically, the spray head 240 is used to spray the carbon dioxide to be stored delivered by the gas delivery pipe 220 into the abandoned well after the exhaust end of the gas delivery pipe 220 is inserted into the abandoned well through the wellhead, which can not only ensure the sufficiency and uniformity of the carbon dioxide storage, but also can speed up the progress of the carbon dioxide storage, thereby improving the storage efficiency of the carbon dioxide.

[0029] In some embodiments, in addition to the structure given above, the carbon dioxide storage device 200 further comprises a water tank (not shown in the figure), a water pump (not shown in the figure) and a water suction pipe (not shown in the figure), the water tank and the water pump are arranged on the floating platform 100, one end of the water suction pipe is connected to the gas conveying pipe 220, and the other end is connected to the water tank through the water pump. Specifically, after the connector 230 is connected to the wellhead, the water pump is used to pump the water in the accommodation cavity to the water tank through the nozzle 240, the gas conveying pipe 220 and the water suction pipe, so that a pressure difference is formed between the inside and outside of the connector 230, and the connector 230 is pressed on the ground around the wellhead by using the pressure difference, so that the stability of the connection between the connector 230 and the wellhead of the abandoned well is improved, and the connector 230 is prevented from shaking in the water, thereby affecting the conveying of the carbon dioxide to be stored in the abandoned well through the conveying pipe 220. It can be understood that the nozzle 240 is used for spraying the carbon dioxide to be stored and also for sucking the water in the accommodation cavity of the connector 230.

[0030] In some embodiments, referring to Figure 2 The accommodation cavity of the connector 230 comprises an upper accommodation cavity, a middle accommodation cavity and a lower accommodation cavity, the upper accommodation cavity, the middle accommodation cavity and the lower accommodation cavity are sequentially arranged and spaced apart along the direction from the connecting end to the receiving end of the connector 230, the spigot 232 is connected to the upper accommodation cavity, the exhaust end of the gas conveying pipe 220 is inserted into the upper accommodation cavity through the spigot 232, the middle accommodation cavity and the upper accommodation cavity are connected through an upper through hole, the middle accommodation cavity and the lower accommodation cavity are connected through a lower through hole, and the receiving port 231 is connected to the lower accommodation cavity. When the connector 230 is connected to the wellhead, the wellhead is received in the lower accommodation cavity through the receiving port 231, and the wellhead is aligned with the lower through hole.

[0031] Further, the nozzle 240 is a self-advancing nozzle, in addition to the structure given above, the carbon dioxide storage device 200 further comprises a buffer guide 250, the buffer guide 250 has a through hole penetrating from one end to the other end, the buffer guide 250 is arranged in the middle accommodation cavity, one end of the buffer guide 250 abuts against the inner wall of the middle accommodation cavity where the upper through hole is arranged, and the other end of the buffer guide 250 abuts against the inner wall of the middle accommodation cavity where the lower through hole is arranged, the two openings of the through hole are respectively aligned with and connected to the upper through hole and the lower through hole, and the through hole is used to connect the upper accommodation cavity and the lower accommodation cavity. Specifically, after the connector 230 is connected to the wellhead, the self-advancing nozzle sprays the carbon dioxide to be stored conveyed by the gas conveying pipe 220 outward, so that the reaction force generated during spraying makes the nozzle pass through the through hole of the buffer guide 250 into the lower accommodation cavity, and the nozzle is inserted into the abandoned well through the wellhead, so that the carbon dioxide to be stored conveyed by the gas conveying pipe 220 is sprayed into the abandoned well.

[0032] As one of the embodiments, the self-propelled nozzle includes a nozzle (not shown in the figure), a propulsion mechanism (not shown in the figure), a connecting structure (not shown in the figure), and a guiding mechanism (not shown in the figure), wherein the nozzle is the place where carbon dioxide is sprayed out, and is usually designed in a specific shape and size to control the spraying direction and flow of carbon dioxide, and can be made of wear-resistant and corrosion-resistant materials to adapt to the physical and chemical properties of carbon dioxide and the working environment; the propulsion mechanism generally includes a spiral blade or similar structure, which functions to generate forward propulsion by using the reaction force when carbon dioxide is sprayed out, and the angle and shape of the spiral blade are carefully designed to ensure effective propulsion under the action of carbon dioxide flow; the connecting structure is used to connect the nozzle with the gas conveying pipe 220 conveying carbon dioxide, to ensure stable supply of carbon dioxide and fixation of the nozzle, and usually needs to have good sealing and pressure resistance to prevent carbon dioxide leakage; the guiding mechanism can help the nozzle 240 maintain the correct direction to prevent it from deviating or shaking during vertical downward conveying of carbon dioxide, and can include some guide wheels, guide rails or other structures to ensure that the nozzle 240 can stably advance along the predetermined path, such as the buffer guide 250 described in the present application which can be used as a guiding mechanism.

[0033] In the present embodiment, when carbon dioxide enters the self-propelled nozzle through the gas conveying pipe 220, due to the design of the nozzle, carbon dioxide will be sprayed out at high speed, and according to Newton's third law, the sprayed carbon dioxide will generate a reaction force in the opposite direction, so that in the case of vertical downward conveying of carbon dioxide, the reaction force will push the nozzle 240 downward, and finally the nozzle 240 will pass through the through hole of the buffer guide 250 into the lower accommodating cavity, and be inserted into the abandoned well through the well mouth. Specifically, when carbon dioxide is sprayed out of the nozzle, the high-speed flow will generate a rotating force and a forward thrust on the spiral blade or the propulsion mechanism, and the design of the spiral blade enables the flow of carbon dioxide to be converted into the forward driving force of the nozzle 240, while the guiding mechanism ensures that the nozzle 240 advances stably in the vertical direction without deviating from the predetermined path. It can be understood that the design of such a self-propelled nozzle can realize automatic propulsion during vertical downward conveying of carbon dioxide, improve work efficiency, reduce dependence on external power equipment, and also enable more accurate control of the conveying position and flow of carbon dioxide.

[0034] As one of the embodiments, please refer to Figure 2The buffer guide 250 comprises a main body 251, a connecting column 252 and a plug 253. One end of the connecting column 252 is arranged on one end of the main body 251, and the plug 253 is arranged on the other end of the connecting column 252. The main body 251 is arranged in the middle accommodating cavity, the connecting column 252 is arranged in the upper through hole, and the plug 253 is arranged in the upper accommodating cavity. One end of the main body 251 provided with the connecting column 252 is in abutment with the inner wall of the middle accommodating cavity provided with the upper through hole, and the other end of the main body 251 not provided with the connecting column 252 is in abutment with the inner wall of the middle accommodating cavity provided with the lower through hole. The side wall of the connecting column 252 is in abutment with the hole wall of the upper through hole, and the side of the plug 253 close to the main body 251 is in abutment with the inner wall of the upper accommodating cavity provided with the upper through hole. The two opposite hole openings of the through hole are respectively located on the end of the plug 253 away from the main body 251 and on the end of the main body 251 not provided with the connecting column 252. In this embodiment, the main body 251, the connecting column 252 and the plug 253 can be made of elastic materials commonly used in the art, such as rubber, foamed silica gel, polyurethane (PU) and the like, so as to further improve the sealing performance between the three accommodating cavities.

[0035] As one of the embodiments, please refer to Figure 2 In addition to the structure given above, the carbon dioxide storage device 200 further comprises a sealing ring 260 and at least one buffer spring (not shown in the figure). The sealing ring 260 is located between the end of the main body 251 provided with the connecting column 252 and the inner wall of the middle accommodating cavity provided with the upper through hole, and surrounds the connecting column 252. The buffer spring is located between the end of the main body 251 provided with the connecting column 252 and the inner wall of the middle accommodating cavity provided with the upper through hole. The opposite ends of the buffer spring are in abutment with the end of the main body 251 provided with the connecting column 252 and the inner wall of the middle accommodating cavity provided with the upper through hole, respectively. It can be understood that the buffer spring and the sealing ring 260 are arranged between the end of the main body 251 provided with the connecting column 252 and the inner wall of the middle accommodating cavity provided with the upper through hole in this embodiment, which can effectively improve the buffer performance and the sealing performance. Preferably, when the buffer spring comprises a plurality of buffer springs, the plurality of buffer springs are arranged around the connecting column 252.

[0036] In some embodiments, please refer to Figure 2The adapter 230 is trumpet-shaped, i.e. the thickness of the adapter 230 gradually decreases along the direction from the receiving end to the connecting end; correspondingly, the accommodating cavity of the adapter 230 is also trumpet-shaped, i.e. the shape of the accommodating cavity matches the shape of the adapter 230. It can be understood that, under the premise that the accommodating cavity of the adapter 230 is trumpet-shaped, when the wellhead of the abandoned well has a large size, the wellhead will be located close to the receiving opening 231 in the accommodating cavity after being received in the accommodating cavity of the adapter 230, and when the wellhead of the abandoned well has a small size, the wellhead will be located away from the receiving opening 231 in the accommodating cavity after being received in the accommodating cavity of the adapter 230, that is, the trumpet-shaped accommodating cavity can make the adapter 230 applicable to the wellheads of abandoned wells with different sizes, and the application range is wider.

[0037] Please refer to Figure 3 , Figure 3 is a flowchart of a carbon dioxide sealing method. The embodiment provides a carbon dioxide sealing method for an underwater abandoned well, which is applied to the carbon dioxide sealing system described above, and includes the following steps 301 to 304 (abbreviated as S301 to S304), i.e. S301, inserting the adapter and the gas conveying pipe with one end arranged in the adapter into the water; S302, butting the adapter with the wellhead of the underwater abandoned well, so as to receive the wellhead in the adapter through the receiving opening of the adapter, and abut the end of the adapter with the receiving opening against the ground around the wellhead; S303, inserting the one end of the gas conveying pipe in the adapter into the abandoned well through the wellhead; and S304, conveying the carbon dioxide to be sealed into the abandoned well by using the gas conveying pipe. It should be noted that the details of the carbon dioxide sealing method, such as extracting the water in the accommodating cavity to form a pressure difference between the inside and outside of the adapter 230 to press the adapter 230 tightly against the seabed, and the self-propelled nozzle is propelled by itself during the process of spraying carbon dioxide and inserted into the abandoned well through the wellhead, can be found in the above description of the carbon dioxide sealing system, and will not be described here again.

[0038] The above embodiments are only preferred implementations of the present application, and are not the only limitations on the carbon dioxide storage system and the carbon dioxide storage method. Based on the above embodiments, those skilled in the art can make flexible settings according to actual application scenarios. It can be understood that through the implementation of the above embodiments of the present application, the carbon dioxide storage system includes a floating platform 100 for floating on the water surface and a carbon dioxide storage device 200 arranged on the floating platform 100. The carbon dioxide storage device 200 is composed of a gas delivery pipe 220, a gas storage tank 210 for storing carbon dioxide, and a docking head 230 having a containing cavity. The docking head 230 has opposite connecting ends and receiving ends. The receiving end is provided with a receiving opening 231 in communication with the containing cavity. The connecting end is provided with a socket 232 in communication with the containing cavity. The gas delivery pipe 220 has opposite gas inlet and outlet ends. The gas inlet end is in communication with the gas storage tank 210. The gas outlet end is inserted into the containing cavity through the socket 232. The docking head 230 is used to receive the wellhead in the containing cavity through the receiving opening 231 when the docking head 230 is docked with the wellhead of the abandoned well underwater, and the receiving end is abutted on the ground around the wellhead. The gas inlet end is used to lead the carbon dioxide in the gas storage tank 210. The gas outlet end is used to insert the carbon dioxide into the abandoned well through the wellhead after the docking head 230 is docked with the wellhead. Therefore, the present application can transport the carbon dioxide to the abandoned well underwater for storage, realize the organic combination of the abandoned well underwater and the carbon dioxide storage, achieve the integration of offshore oil exploration and carbon dioxide storage, reduce the emission of carbon dioxide, promote the development of environmental protection, improve the utilization rate of the abandoned well underwater, and reduce the environmental burden of the offshore oil industry. Moreover, the entire underwater part (i.e., the gas delivery pipe 220 and the docking head 230) of the carbon dioxide storage system does not contain any electrical equipment, is easy to maintain, has good safety, has strong applicability, and can obtain good stability. In addition, it is very convenient to extract the carbon dioxide stored in the abandoned well for related uses in the future.

[0039] It should be noted that the several embodiments illustrated in the above-described are for the purpose of simplifying the present application and are not meant to limit the present application to a particular embodiment, and properly belong, by way of illustration and example only, to the scope of the present application. Obviously, many modifications and changes are possible in light of the above indications. It is therefore to be understood that the application disclosed herein in its broader aspects is not limited to any given embodiment, and that the application should only be limited by the appended claims. It will be understood by those skilled in the art that, although the present application has been described in relation to the preceding examples, various modifications can be made which will come within the scope of the present application. Accordingly, modifications such as these are intended to be included within the scope of the application. It is also to be understood that the following claims are to cover all generic and specific features of the applications described herein. In particular, any claim that is dependent on another can contain features that are not present in the specific embodiments to which that claim is directed.

[0040] Moreover, those skilled in the art will appreciate that the application described herein is susceptible to variations and / or modifications as will no doubt suggest themselves to those skilled in the art, and do not depart from the spirit and scope of the application. Accordingly, the above disclosure is intended to be illustrative only and not limiting of the scope of the application as contemplated by the application.

Claims

1. A carbon dioxide sequestration system for abandoned underwater wells, characterized in that, The device includes a floating platform and a carbon dioxide storage device. The floating platform is used to float on the water surface, and the carbon dioxide storage device is disposed on the floating platform. The carbon dioxide storage device includes a gas storage tank, a gas supply pipe, and a connector with a accommodating cavity. The connector also has a connecting end and a receiving end. The receiving end has a receiving port communicating with the accommodating cavity, and the connecting end has a plug communicating with the accommodating cavity. The gas supply pipe has a gas inlet end and a gas outlet end. The gas inlet end is connected to the gas storage tank, and the gas outlet end is inserted into the accommodating cavity through the plug. The gas storage tank is used to store carbon dioxide to be sealed; the connector is used to receive the wellhead of an underwater abandoned well into the receiving cavity through the receiving port, and to make the receiving end abut against the ground around the wellhead; the air inlet is used to draw out the carbon dioxide to be sealed from the gas storage tank; the exhaust end is used to insert into the abandoned well through the wellhead after the connector is connected to the wellhead, so as to introduce the carbon dioxide to be sealed into the abandoned well. The carbon dioxide storage device also includes a nozzle, which is located on the exhaust end and connected to the gas transmission pipe. The nozzle is used to inject the carbon dioxide to be stored, which is transported by the gas transmission pipe, into the abandoned well after the exhaust end is inserted into the abandoned well through the wellhead. The receiving cavity includes an upper receiving cavity, a middle receiving cavity, and a lower receiving cavity. The upper receiving cavity, the middle receiving cavity, and the lower receiving cavity are arranged sequentially and spaced apart from each other along the direction from the connecting end to the receiving end. The insertion port communicates with the upper receiving cavity, and the exhaust end is inserted into the upper receiving cavity through the insertion port. The middle receiving cavity is connected to the upper receiving cavity through an upper through hole, and the middle receiving cavity is connected to the lower receiving cavity through a lower through hole. The receiving port communicates with the lower receiving cavity. The connector is specifically used to receive the wellhead into the lower receiving cavity through the receiving port and align the wellhead with the lower through hole when docking with the wellhead. The nozzle is a self-feeding nozzle. The carbon dioxide storage device also includes a buffer guide. The buffer guide has a through hole extending from one end to the opposite end. The buffer guide is disposed in the middle accommodating cavity. One end of the buffer guide abuts against the inner wall of the middle accommodating cavity where the upper through hole is provided, and the opposite end abuts against the inner wall of the middle accommodating cavity where the lower through hole is provided. The two opposite openings of the through hole are respectively aligned and connected to the upper through hole and the lower through hole. The through hole is used to connect the upper accommodating cavity and the lower accommodating cavity. The self-propelled nozzle is used to spray the carbon dioxide to be sealed outward from the gas pipeline after the connector is connected to the wellhead. The reaction force generated during the spraying allows it to pass through the through hole into the lower receiving cavity and be inserted into the abandoned well through the wellhead, so as to spray the carbon dioxide to be sealed out from the gas pipeline into the abandoned well.

2. The carbon dioxide sequestration system according to claim 1, characterized in that, The carbon dioxide storage device also includes a water tank, a water pump, and a water pumping pipe. The water tank and the water pump are both mounted on the floating platform. One end of the water pumping pipe is connected to the gas transmission pipe, and the other end is connected to the water tank through the water pump. The water pump is used to pump water from the accommodating cavity into the water tank through the nozzle, the gas supply pipe and the water pumping pipe after the connector is connected to the wellhead, so as to create a pressure difference between the inside and outside of the connector and use the pressure difference to press the connector tightly onto the ground around the wellhead.

3. The carbon dioxide sequestration system according to claim 1, characterized in that, The buffer guide includes a main body, a connecting post, and a plug. One end of the connecting post is disposed on one end of the main body, and the plug is disposed on the other end of the connecting post. The main body is disposed in the middle receiving cavity, the connecting post is disposed in the upper through hole, and the plug is disposed in the upper receiving cavity. The end of the main body with the connecting post abuts against the inner wall of the middle receiving cavity where the upper through hole is located, and the other end without the connecting post abuts against the inner wall of the middle receiving cavity where the lower through hole is located. The side wall of the connecting post abuts against the wall of the upper through hole. The side of the plug near the main body abuts against the inner wall of the upper receiving cavity where the upper through hole is located. The two openings opposite to the through hole are respectively located on the end of the plug away from the main body and on the end of the main body without the connecting post.

4. The carbon dioxide sequestration system according to claim 3, characterized in that, The carbon dioxide storage device also includes a sealing ring, which is located between the end of the main body where the connecting post is located and the inner wall of the middle accommodating cavity where the upper through hole is located, and surrounds the connecting post.

5. The carbon dioxide sequestration system according to claim 3, characterized in that, The carbon dioxide storage device further includes at least one buffer spring, which is located between the end of the main body with the connecting post and the inner wall of the middle accommodating cavity with the upper through hole. The two opposite ends of the buffer spring abut against the end of the main body with the connecting post and the inner wall of the middle accommodating cavity with the upper through hole, respectively.

6. The carbon dioxide sequestration system according to claim 1, characterized in that, The thickness of the connector gradually decreases along the direction from the receiving end to the connecting end, and the shape of the receiving cavity matches the shape of the connector.

7. The carbon dioxide sequestration system according to claim 1, characterized in that, The floating platform includes a vessel.

8. A method for carbon dioxide sequestration in abandoned underwater wells, characterized in that, Applied to the carbon dioxide sequestration system according to any one of claims 1 to 7, comprising: Insert the connector and the gas pipe with one end located inside the connector underwater; The connector is connected to the opening of an abandoned underwater well so that the well opening is received within the connector through the receiving port of the connector, and the end of the connector having the receiving port abuts against the ground around the well opening. One end of the gas pipeline located inside the connector is inserted into the abandoned well through the wellhead; Carbon dioxide to be sealed is transported to the abandoned well via the gas pipeline.

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