A sealed circulation device for ash injection in permanently abandoned wells and its usage method

Abstract

This invention discloses a sealed circulation device for ash injection in permanently abandoned wells and its usage method. In the circulation device, a connecting cylinder receiving frame has a wire-carrying upper flange fixed to its upper end and a connecting cylinder mounting groove at its lower part. A variable-diameter connecting cylinder assembly is connected to the mounting groove via adjusting bolts and bolt caps. A sealing sleeve is fixed to the outside of the variable-diameter connecting cylinder, and the lower part of the variable-diameter connecting cylinder and the sealing sleeve can be placed inside the surface casing of the permanently abandoned wellhead. The wire-carrying upper flange can be connected to a blowout preventer (BOP), and the ash injection string can be lowered into the well from the BOP and the sealed circulation device for ash injection in the abandoned well, forming a low-pressure sealed circulation channel between the sealed circulation device and the ash injection string. This invention is easy to adjust and has a wide range of applications. By using this invention for the construction of permanently abandoned wells, it can protect the environment while avoiding huge fines caused by non-compliance with emission regulations, effectively reducing production costs.

Description

Technical Field

[0001] This invention relates to a treatment device for permanently abandoned wells in the petroleum industry, and more particularly to a sealed circulation device for injecting ash into permanently abandoned wells and its method of use. Background Technology

[0002] As block development progresses, wells that have been in operation for a long period in the early stages of the oilfield, as well as production wells abandoned due to changes in the formation leading to casing deformation or damage, need to be permanently abandoned. The traditional method for disposing of permanently abandoned wells is as follows:

[0003] 1. After retrieving the original well tubing, retrieve the tools left in the well;

[0004] 2. After the wellbore is emptied, cement slurry is injected into the production layer for cementing. After the cement slurry has set, the ash surface is explored: the thickness of the ash surface above the production layer should exceed 200m. At the first ash plug, which is the ash plug formed after the slurry is injected into the production layer, at the overlap of the cement return height of the oil layer casing and the technical casing above, a suspended ash plug of more than 300m is injected.

[0005] 3. After cutting the annular steel plate, use a hydraulic cutter to cut the oil layer casing and the technical casing annulus above the cement return height, and remove the cut oil layer casing.

[0006] 4. Next, use a hydraulic cutter to cut the surface casing and the technical casing above the cement return height of the annulus. Then, inject mortar plugs into the area between 10m below the mud surface and 200m below the cement return height of the annulus between the oil layer casing and the technical casing. 。

[0007] Because it is impossible to establish a sealed ash injection circulation channel after cutting the casing head and annular steel plate in a permanently abandoned well, if the permanently abandoned well in an offshore oil platform is to be disposed of, the liquid returned from the ash injection circulation can only be discharged directly into the sea; if the oil and gas well on land is to be disposed of, the liquid returned from the circulation can be discharged into a sludge pool.

[0008] With the upgrading and improvement of environmental protection laws and regulations, the traditional construction methods for permanently abandoned wells pose serious hidden dangers to safe and clean production.

[0009] In the prior art, there are many quick connection devices for casings, such as the patented technology described below, but there are few disclosed sealing and drainage circulation devices for ash injection in permanently abandoned wells.

[0010] Patent No. CN202020894775.9 discloses a quick connection device for BOP connecting sleeves. Its design principle is to use a pressure plate, an eccentric handwheel and a sealing device. By manually pressing the eccentric handwheel against the wall until it is tangent to the support part, the pressure plate is driven to compact the sealing device, thereby realizing the quick connection of the upper and lower sections of the BOP connecting sleeve. By flipping open the eccentric handwheel, the upper and lower sections of the connecting sleeve can be quickly disassembled.

[0011] Because there are no casings of the same size to connect during the construction of permanently abandoned wells, it is impossible to form a sealed ash injection circulation channel. Furthermore, after cutting the annular steel plate, the upper surface of the casing remaining in the well is uneven. Therefore, this device cannot meet the construction requirements for establishing an ash injection circulation channel in permanently abandoned wells.

[0012] The annular sealed wellhead disclosed in patent number CN201520942038.0 includes a casing sub and a surface casing. The surface casing is inserted into the inner wall of the upper port of the annular wellhead. The casing sub is inserted into the well from inside the surface casing. A sealing connection disc is provided between the casing sub and the surface casing. The sealing connection disc has threads on both its inner and outer walls. The inner wall of the surface casing has threads, and the outer wall of the casing sub has threads. The connection method between the sealing connection disc and the casing sub and the surface casing is a threaded connection.

[0013] Because there are no casings of the same size to connect during the construction of permanently abandoned wells, it is impossible to form a sealed ash injection circulation channel. Furthermore, after cutting the annular steel plate, the upper surface of the casing remaining in the well is uneven. Therefore, this device cannot meet the construction requirements for establishing an ash injection circulation channel in permanently abandoned wells.

[0014] CN201520090423.7 A quick connection device for wellhead casing, designed to serve cluster well drilling technology, the device includes a lower sleeve, a mounting plate, a clamping bolt, a casing, a sealing gasket, an upper sleeve, a clamping bolt, a pin, and a cotter pin. The upper sleeve is a steel ring structure, one side of which is flat and welded to the newly installed casing, and the other side has a groove for installing the sealing gasket. The lower sleeve is a steel ring structure, the inner diameter of which is slightly larger than the outer diameter of the wellhead casing, and four sets of double-ear plates are evenly welded around the outer ring. The four mounting plates are connected to the outer ring of the lower sleeve by pins.

[0015] Because there are no casings of the same size to connect during the construction of permanently abandoned wells, it is impossible to form a sealed ash injection circulation channel. Furthermore, after cutting the annular steel plate, the upper surface of the casing remaining in the well is uneven. Therefore, this device cannot meet the construction requirements for establishing an ash injection circulation channel in permanently abandoned wells. Summary of the Invention

[0016] The purpose of this invention is to provide a sealed circulation device and its method for grouting permanent abandoned wells. After the annular steel plate is cut during the treatment of permanent abandoned wells, a low-pressure sealed circulation channel can be formed with the remaining surface casing while the annular steel plate is removed. This eliminates the hidden dangers that seriously affect the environment and safe and clean production during the construction of permanent abandoned wells, protects the environment, reduces the labor intensity of construction workers, and improves construction efficiency.

[0017] The technical solution of this invention is:

[0018] A sealed circulation device for injecting ash into a permanently abandoned well, wherein:

[0019] The upper end of the connecting tube receiving frame is fixed with the wire carrier flange, and the lower part is provided with a connecting tube mounting groove. In the connecting tube mounting groove, the assembled tube segments of the variable diameter connecting tube are connected by adjusting bolts and bolt caps.

[0020] The sealing sleeve is fixed to the outside of the variable diameter connecting cylinder, and the lower part of the variable diameter connecting cylinder and the sealing sleeve can be placed inside the surface casing of the permanent abandoned wellhead.

[0021] The cable carrier flange can be connected to the blowout preventer (BOP), and the ash injection string can be lowered into the well from the BOP and the sealed circulation device for ash injection in the abandoned well, forming a low-pressure sealed circulation channel between the sealed circulation device for ash injection in the abandoned well and the ash injection string.

[0022] Preferably, the assembled cylindrical pieces of the variable diameter connecting cylinder are convex in shape, with the upper width being smaller than the lower width. The upper part of the assembled cylindrical pieces is installed in the connecting cylinder mounting groove in the connecting cylinder receiving frame by adjusting bolts and bolt caps. The lower part of the assembled cylindrical pieces is an arc-shaped piece, and the variable diameter connecting cylinder is formed by assembling the assembled cylindrical pieces.

[0023] Preferably, the lower body of the assembled cylindrical segment is wedge-shaped and has a sawtooth thread on the outer side of the lower body. The variable diameter connecting cylinder formed by assembling the assembled cylindrical segment is a wedge-shaped cylinder. At least two rows of threaded holes are provided on the upper outer side of the lower body of the assembled cylindrical segment, and a rubber sleeve fixing bolt for fixing the sealing rubber sleeve can be installed in the threaded holes.

[0024] Preferably, the number of connecting cylinder mounting slots in the connecting cylinder receiving frame is set to an even number of six or more, and a bolt cap is fixed inside each connecting cylinder mounting slot. At the same time, a bolt cap is connected to the connecting cylinder receiving frame outside the connecting cylinder mounting slot through a threaded hole, and a sealing gasket is installed between the bolt cap on the outside and the connecting cylinder receiving frame. The adjusting bolt is connected between two bolt caps, and the assembled cylindrical plate of the variable diameter connecting cylinder is fixed outside the adjusting bolt inside the connecting cylinder mounting slot. When the adjusting bolt is rotated, the assembled cylindrical plate can move with the adjusting bolt.

[0025] Preferably, the assembled cylindrical plate is fixed to the outside of the adjusting bolt by a retaining spring. The upper part of the assembled cylindrical plate is provided with a cylindrical plate mounting hole, and the outer wall of the adjusting bolt is provided with an axial retaining groove. The retaining spring is installed on the outside of the adjusting bolt and is held between the axial retaining groove of the adjusting bolt and the cylindrical plate mounting hole of the assembled cylindrical plate.

[0026] Preferably, the wire carrier flange is a national standard flange, the size of the wire carrier flange is the same as that of the blowout preventer flange, and a standard steel ring groove is provided on the upper end face; a bolt connection hole corresponding to the blowout preventer flange is provided on the upper end face of the wire carrier flange outside the steel ring groove, and a flange connection bolt can be installed in the bolt connection hole.

[0027] Preferably, the lower end face of the wire carrier flange is welded to the connecting cylinder support frame, the center holes of the wire carrier flange and the connecting cylinder support frame are concentric and have the same diameter, and the center holes of the wire carrier flange and the connecting cylinder support frame are larger than the outer diameter of the ash injection pipe column.

[0028] Preferably, the outer diameter of the connecting cylinder support frame is larger than the outer diameter of the surface sleeve, the upper outer diameter of the variable diameter connecting cylinder is larger than the inner diameter of the surface sleeve and the lower outer diameter matches the inner diameter of the surface sleeve; lifting lugs are symmetrically welded on both sides of the upper end of the connecting cylinder support frame.

[0029] Preferably, the lower end of the sealing sleeve fixed to the upper part of the variable diameter connecting cylinder is at least 40 cm longer than the lower end of the variable diameter connecting cylinder.

[0030] A method of using a sealed circulation device for ash injection in a permanently abandoned well includes the following steps:

[0031] A. Cut the oil layer casing and annular steel plate in the permanently abandoned well and remove the oil layer casing;

[0032] B. Use a sealed circulation device to hoist the ash injection into the permanent abandoned well above the surface casing at the wellhead;

[0033] C. Adjust the size of the variable diameter connecting cylinder according to the inner diameter of the surface casing in the abandoned well;

[0034] D. Insert the lower edge of the sealing sleeve into the surface sleeve, lower the hoisting tool, and place the variable diameter connecting cylinder into the surface sleeve;

[0035] E. After connecting the sealed circulation device for ash injection in the permanently abandoned well to the blowout preventer and connecting the sewage pipeline to the blowout preventer's drain port, carry out cement injection sealing construction, and discharge the liquid discharged during the cement injection sealing construction into the sewage container.

[0036] The significant advantages of this invention are:

[0037] 1. This invention is a special tool for constructing a pollution-free, green ash injection circulation channel for permanently abandoned wells. It effectively solves the environmental pollution problems caused by the inability to establish a sealed ash injection circulation channel, the inability to connect the wastewater returned from the well to a container for the wastewater, and the direct discharge of the circulating return liquid into the sea during the construction and disposal of permanently abandoned wells in oil fields, especially offshore oil fields.

[0038] 2. The variable diameter connecting cylinder in this device is assembled from assembled cylinder plates. A sealing sleeve is fixed to the outside of the variable diameter connecting cylinder. The sealing sleeve and the lower part of the variable diameter connecting cylinder are lowered into the surface casing. The connecting cylinder receiving frame, wire carrier flange and blowout preventer formed a ash injection circulation channel on the upper end face of the surface casing. The sewage in the well is discharged to the sewage tank or sewage pool through the sewage pipeline connected to the sewage outlet of the blowout preventer. Of course, it can also be other sewage holding equipment.

[0039] 3. The lower body of the assembled cylindrical plates in the variable diameter connecting cylinder is wedge-shaped, and the resulting variable diameter connecting cylinder is a wedge-shaped cylinder with a sawtooth thread on the outer side of the lower body, which can further improve the sealing performance with the sealing sleeve without damaging the sealing sleeve.

[0040] 4. The variable diameter connecting cylinder in this invention is assembled from assembled cylindrical plates. Its outer diameter is adjustable and easy to adjust, and it has a wide range of applications. By constructing permanent abandoned wells, this invention can protect the environment and avoid huge fines caused by non-compliance with emission regulations, thus effectively reducing production costs.

[0041] 5. The device of this invention is small in size, light in weight, and easy to hoist and disassemble. While cutting the annular steel plate in the permanent abandoned well, it can form a low-pressure seal with the surface casing of different sizes in different wells by its own weight, establish a mortar injection circulation channel, eliminate safety and environmental hazards in the construction of permanent abandoned wells, and has significant use effect and can generate good economic benefits. Attached Figure Description

[0042] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings:

[0043] Figure 1 This is a schematic diagram of the structure of the device of the present invention.

[0044] In the diagram: 1. Cable carrier flange, 1-1. Flange connecting bolt, 1-2. Steel ring groove, 2. Connecting cylinder support frame, 2-1. Lifting lug, 3. Variable diameter connecting cylinder, 4. Sealing sleeve, 5. Sleeve fixing bolt, 6. Bolt cap, 7. Adjusting bolt, 8. Snap ring. Detailed Implementation

[0045] The accompanying drawings are for reference and illustration only and are not intended to limit the scope of protection of this invention. The technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0047] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0048] See Figure 1 A sealed circulation device for injecting ash into a permanently abandoned well, wherein:

[0049] The upper end of the connecting tube receiving frame 2 is fixed with the wire carrier flange 1, and the lower part is provided with a connecting tube mounting groove. In the connecting tube mounting groove, the assembled tube segments of the variable diameter connecting tube 3 are connected by adjusting bolts 7 and bolt caps 6.

[0050] The sealing sleeve 4 is fixed to the outside of the variable diameter connecting cylinder 3, and the lower part of the variable diameter connecting cylinder 3 and the sealing sleeve 4 can be placed inside the surface casing of the permanent abandoned wellhead.

[0051] The upper flange 1 of the wire carrier can be connected to the blowout preventer, and the ash injection string can be lowered into the well from the blowout preventer and the sealed circulation device for ash injection in the abandoned well, forming a low-pressure sealed circulation channel between the sealed circulation device for ash injection in the abandoned well and the ash injection string.

[0052] This invention can be installed on the surface casing remaining after the annular steel plate is cut off at the head of a permanently abandoned well. The sealing sleeve 4 at the bottom of the device is placed inside the surface casing at the head of the permanently abandoned well, and the upper flange 1 of the wire carrier is connected to the blowout preventer. A ash injection pipe string is inserted into the blowout preventer and the device to form a low-pressure sealed circulation channel. The liquid that is replaced by ash after circulation can be discharged through the sewage pipeline connected to the drain port of the blowout preventer to a device for holding sewage, such as a sewage tank, sewage pool, or other devices and equipment that can hold sewage.

[0053] Based on the above embodiment one, the present invention also has the following embodiments:

[0054] In a preferred embodiment: the assembled cylindrical pieces of the variable diameter connecting cylinder 3 are convex in shape, with the upper width being smaller than the lower width. The upper part of the assembled cylindrical pieces is installed in the connecting cylinder mounting groove in the connecting cylinder receiving frame 2 by adjusting bolts 7 and bolt caps 6. The lower part of the assembled cylindrical pieces is an arc-shaped piece, and the variable diameter connecting cylinder 3 is formed by assembling the assembled cylindrical pieces.

[0055] In a preferred embodiment: the lower body of the assembled cylindrical section is wedge-shaped and has serrated threads on its outer side. The variable-diameter connecting cylinder 3 formed by assembling the assembled cylindrical sections is a wedge-shaped cylinder. At least two rows of threaded holes are provided on the upper outer side of the lower body of the assembled cylindrical section, into which the sealing sleeve fixing bolts 5 can be inserted. The serrated threads on the lower part of the assembled cylindrical section improve the sealing effect of the sealing sleeve 4 between the variable-diameter connecting cylinder 3 and the inner wall of the outer sleeve. The serrated threads on the lower part of the variable-diameter connecting cylinder 3 not only improve the sealing effect but also do not damage the sealing sleeve 4.

[0056] In a preferred embodiment: the number of connecting cylinder mounting slots in the connecting cylinder receiving frame 2 is set to an even number of six or more, and a bolt cap 6 is fixed inside each connecting cylinder mounting slot. Simultaneously, a bolt cap 6 is connected to the connecting cylinder receiving frame 2 outside the connecting cylinder mounting slot via a threaded hole, and a sealing gasket is installed between the bolt cap 6 on the outside and the connecting cylinder receiving frame 2. An adjusting bolt 7 is connected between two bolt caps 6. The assembled cylindrical section of the variable diameter connecting cylinder 3 is fixed outside the adjusting bolt 7 inside the connecting cylinder mounting slot. When the adjusting bolt 7 is rotated, the assembled cylindrical section can move with the adjusting bolt 7. The adjusting bolt 7 can adjust the size of the variable diameter connecting cylinder 3 to accommodate various models of surface casing, facilitating the disposal of more permanently abandoned wells.

[0057] In a preferred embodiment: the assembled cylindrical section is fixed to the outside of the adjusting bolt 7 by a retaining spring 8. The upper part of the assembled cylindrical section has a cylindrical section mounting hole, and the outer wall of the adjusting bolt 7 has an axial groove. The retaining spring 8 is installed outside the adjusting bolt 7 and is held between the axial groove of the adjusting bolt 7 and the cylindrical section mounting hole of the assembled cylindrical section. Because the retaining claw of the retaining spring 8 is engaged in the axial groove on the outer wall of the adjusting bolt 7, and the spring ring of the retaining spring 8 is installed outside the adjusting bolt 7 and located in the cylindrical section mounting hole of the assembled cylindrical section, when the adjusting bolt 7 moves inward or outward in the connecting cylinder mounting groove of the connecting cylinder support frame 2, the assembled cylindrical section can move along with it.

[0058] In a preferred embodiment: the wire carrier flange 1 is a national standard flange, with dimensions identical to the blowout preventer flange, and a standard steel ring groove 1-2 is provided on its upper end face; bolt connection holes corresponding to the blowout preventer flange are provided on the upper end face of the wire carrier flange 1 outside the steel ring groove 1-2, and flange connection bolts 1-1 can be installed in the bolt connection holes. The blowout preventer is connected to this device via the steel ring in the steel ring groove 1-2 and the flange connection bolts 1-1.

[0059] In a preferred embodiment: the lower end face of the wire carrier flange 1 is welded to the connecting sleeve support 2. The center holes of the wire carrier flange 1 and the connecting sleeve support 2 are concentric and have the same diameter. The center holes of the wire carrier flange 1 and the connecting sleeve support 2 are larger than the outer diameter of the injection tubing string. The circulating fluid returned from downhole can return from between the center holes of the injection tubing string and the wire carrier flange 1 and the connecting sleeve support 2 to the blowout preventer (BOP) and then be discharged to the waste fluid collection equipment via a drain line connected to the BOP drain port.

[0060] In a preferred embodiment: the outer diameter of the connecting sleeve support 2 is larger than the outer diameter of the surface sleeve; the upper outer diameter of the variable diameter connecting sleeve 3 is larger than the inner diameter of the surface sleeve, and the lower outer diameter matches the inner diameter of the surface sleeve; lifting lugs 2-1 are symmetrically welded to both sides of the upper end of the connecting sleeve support 2. This allows for connection with lifting tools for easy lifting. This device can sit on the surface sleeve at the opening of a permanently abandoned well. The lower part of the variable diameter connecting sleeve 3 and the sealing sleeve 4 can be inserted into the surface sleeve. By adjusting the bolt 7 and rotating the variable diameter connecting sleeve 3 outwards, a seal is achieved between the device and the surface sleeve through the sealing sleeve 4.

[0061] In a preferred embodiment, the lower end of the sealing sleeve 4, which is fixed to the upper part of the variable diameter connecting cylinder 3, is at least 40 cm longer than the lower end of the variable diameter connecting cylinder 3. This is more conducive to the sealing between the device and the surface sleeve.

[0062] A method of using a sealed circulation device for ash injection in a permanently abandoned well includes the following steps:

[0063] A. Cut the oil layer casing and annular steel plate in the permanently abandoned well and remove the oil layer casing; During the aforementioned process, the construction personnel carry a sealing circulation device to the construction site, wear protective equipment, cut the reserved annular steel plate, and remove the oil layer casing in the well.

[0064] B. The sealing circulation device is used to hoist the ash injection of the permanent abandoned well onto the surface casing above the wellhead; in the aforementioned process, the sling of the hoisting tool is connected to the hoisting lug 2-1, and the sealing circulation device is hoisted onto the surface casing.

[0065] C. Adjust the size of the variable diameter connecting cylinder 3 according to the inner diameter of the surface casing in the abandoned well; in the aforementioned process, the construction personnel use tools to rotate the clamping structure at the outer end of the adjusting bolt 7, and the rotation of the adjusting bolt 7 causes the variable diameter connecting cylinder 3 to undergo horizontal displacement. The lower outer diameter of the assembled cylinder plate in the diagonal variable diameter connecting cylinder 3 is measured to be consistent with the inner diameter of the surface casing.

[0066] D. Place the lower edge of the sealing sleeve 4 into the surface sleeve, lower the lifting tool, and place the variable diameter connecting cylinder 3 into the surface sleeve; during the aforementioned process, place the lower edge of the sealing sleeve 4 into the surface sleeve, lower the lifting tool until the sling is unloaded, and rotate the adjusting bolt 7 to compress the sealing sleeve 4 through the variable diameter connecting cylinder 3 to form a seal. Remove the sling from the lifting lug 2-1, place the matching steel ring in the steel ring groove 1-2, and connect and fix the carrier flange 1 to the corresponding blowout preventer flange using the connecting bolt 1-1.

[0067] E. After connecting the sealed circulation device for ash injection in the permanently abandoned well to the blowout preventer and connecting the sewage pipeline to the blowout preventer's drain port, carry out cement injection sealing construction, and discharge the liquid discharged during the cement injection sealing construction into the sewage container.

[0068] After construction is completed, the blowout preventer and sewage pipeline are dismantled, and the ash injection device for permanently abandoned wells is separated from the wellhead using hoisting tools.

[0069] The embodiments described above are merely typical examples, but the present invention is not limited to these embodiments. Those skilled in the art can make modifications without departing from the spirit and teachings of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the inventive spirit and concept of the present invention should be included within the protection scope of the present invention. Therefore, the protection scope is not limited to the above description.

Claims

1. A sealed circulation device for injecting ash into permanently abandoned wells, characterized in that: The upper end of the connecting tube receiving frame (2) is fixed with the wire carrier upper flange (1), and the lower part is provided with a connecting tube mounting groove. The assembly tube of the variable diameter connecting tube (3) is connected in the connecting tube mounting groove by adjusting bolts (7) and bolt caps (6). The sealing sleeve (4) is fixed on the outside of the variable diameter connecting tube (3). The lower part of the variable diameter connecting tube (3) and the sealing sleeve (4) can be placed in the surface casing of the permanent abandoned wellhead. The wire carrier upper flange (1) can be connected to the blowout preventer. The ash injection string can be lowered into the well from the blowout preventer and the ash injection sealing circulation device of the abandoned well, forming a low-pressure sealing circulation channel between the ash injection sealing circulation device of the abandoned well and the ash injection string.

2. The sealed circulation device for ash injection in a permanently abandoned well as described in claim 1, characterized in that, The assembled cylindrical pieces of the variable diameter connecting cylinder (3) are convex in shape, with the upper part being narrower than the lower part. The upper part of the assembled cylindrical pieces is installed in the connecting cylinder mounting groove in the connecting cylinder support frame (2) by adjusting bolts (7) and bolt caps (6). The lower part of the assembled cylindrical pieces is an arc-shaped piece. The variable diameter connecting cylinder (3) is formed by assembling the assembled cylindrical pieces.

3. A sealed circulation device for ash injection in a permanently abandoned well as described in claim 1 or 2, characterized in that, The lower body of the assembled cylindrical piece is wedge-shaped and has a sawtooth thread on the outer side. The variable diameter connecting cylinder (3) formed by the assembled cylindrical piece is a wedge-shaped cylinder. At least two rows of threaded holes are provided on the upper outer side of the lower body of the assembled cylindrical piece. The rubber sleeve fixing bolt (5) of the fixing sealing rubber sleeve (4) can be installed in the threaded holes.

4. A sealed circulation device for ash injection in a permanently abandoned well as described in claim 3, characterized in that, The number of connecting cylinder mounting slots in the connecting cylinder support frame (2) is set to an even number of six or more, and a bolt cap (6) is fixed inside each connecting cylinder mounting slot. At the same time, a bolt cap (6) is connected to the connecting cylinder support frame (2) outside the connecting cylinder mounting slot through a threaded hole, and a sealing gasket is installed between the bolt cap (6) on the outside and the connecting cylinder support frame (2). The adjusting bolt (7) is connected between the two bolt caps (6), and the assembled cylindrical piece of the variable diameter connecting cylinder (3) is fixed outside the adjusting bolt (7) in the connecting cylinder mounting slot. When the adjusting bolt (7) is rotated, the assembled cylindrical piece can move with the adjusting bolt (7).

5. A sealed circulation device for ash injection in a permanently abandoned well as described in claim 4, characterized in that, The assembled cylindrical plate is fixed to the outside of the adjusting bolt (7) by a retaining spring (8). The upper part of the assembled cylindrical plate is provided with a cylindrical plate mounting hole. The outer wall of the adjusting bolt (7) is provided with an axial groove. The retaining spring (8) is installed outside the adjusting bolt (7) and is held between the axial groove of the adjusting bolt (7) and the cylindrical plate mounting hole of the assembled cylindrical plate.

6. A sealed circulation device for ash injection in a permanently abandoned well as described in claim 1, characterized in that, The wire carrier flange (1) is a national standard flange. The size of the wire carrier flange (1) is the same as that of the blowout preventer flange and a standard steel ring groove (1-2) is provided on the upper end face. The upper end face of the wire carrier flange (1) outside the steel ring groove (1-2) is provided with bolt connection holes corresponding to the blowout preventer flange and flange connection bolts (1-1) can be installed in the bolt connection holes.

7. A sealed circulation device for ash injection in a permanently abandoned well as described in claim 5, characterized in that, The lower end face of the upper flange (1) of the wire carrier is welded to the connecting tube support frame (2). The center holes of the upper flange (1) and the connecting tube support frame (2) are concentric and have the same diameter. The center holes of the upper flange (1) and the connecting tube support frame (2) are larger than the outer diameter of the ash injection pipe column.

8. A sealed circulation device for ash injection in a permanently abandoned well as described in claim 7, characterized in that, The outer diameter of the connecting tube support frame (2) is greater than the outer diameter of the surface sleeve. The upper outer diameter of the variable diameter connecting tube (3) is greater than the inner diameter of the surface sleeve and the lower outer diameter matches the inner diameter of the surface sleeve. The upper ends of the connecting tube support frame (2) are symmetrically welded with lifting lugs (2-1).

9. A sealed circulation device for ash injection in a permanently abandoned well as described in claim 8, characterized in that, The lower end of the sealing sleeve (4) fixed on the upper part of the variable diameter connecting cylinder (3) is more than 40cm longer than the lower end of the variable diameter connecting cylinder (3).

10. A method of using a sealed circulation device for ash injection in a permanently abandoned well, as described in any one of claims 1-9, characterized in that... Includes the following steps: A. Cut the oil layer casing and annular steel plate in the permanently abandoned well and remove the oil layer casing; B. Use a sealed circulation device to hoist the ash injection into the permanent abandoned well above the surface casing at the wellhead; C. Adjust the size of the variable diameter connecting cylinder (3) according to the inner diameter of the surface casing in the abandoned well; D. Place the lower edge of the sealing sleeve (4) into the surface casing, lower the hoisting tool, and place the variable diameter connecting cylinder (3) into the surface casing; E. After connecting the permanent abandoned well ash injection sealing circulation device to the blowout preventer and connecting the sewage pipeline to the blowout preventer drain port, carry out cement injection sealing construction, and discharge the liquid discharged during the cement injection sealing construction into the sewage container.

Images