Disposable well plugging device and using method

Abstract

The invention relates to a discarded well plugging device and belongs to the field of petroleum well completion, the discarded well plugging device comprises a discarded well and further comprises a plugging body for plugging the discarded well, the plugging body comprises a plugging column, the outer wall of the plugging column is sequentially provided with a packing block, an anchoring block and plugging alloy along the vertical center line of the plugging column, and the plugging column is connected with a heating structure for melting the plugging alloy. The sealing column is made of molten sealing alloy, the molten sealing alloy makes contact with the sealing block to form a sealing layer, the sealing block comprises a metal cone and an expansion rubber plug arranged on the sealing column in a sleeving mode, the metal cone making contact with the sealing body is arranged on the expansion rubber plug in a sleeving mode, and the end of the expansion rubber plug penetrates through the metal cone and extends outwards. The method is simple in construction, low in operation cost, high in airtight sealing effect, stable, reliable and resistant to corrosion.

Description

Technical Field

[0001] The invention belongs to the field of petroleum well completion, and in particular relates to an abandoned well plugging device and a use method thereof. Background Art

[0002] In the later stage of oil and gas resource exploitation, the underground oil and gas resources are close to exhaustion, and the oil and gas wells need to be plugged to complete the complete isolation of the oil and gas resources at the bottom of the well, that is, the plugging of abandoned wells. The plugging of abandoned oil and gas wells mainly needs to consider the following requirements: 1) The formed sealing layer needs to achieve permanent airtightness to prevent the formation oil and gas from entering the ground; 2) The formed sealing layer needs to be corrosion-resistant to prevent the sealing layer from corroding in the underground environment and causing the plugging failure; 3) The formed sealing layer needs to withstand a certain pressure.

[0003] In response to the above requirements, conventional abandoned well plugging processes usually use cement as a material for plugging. Cement is a brittle material. When plugging, due to changes in ground stress, cement is prone to brittle failure, resulting in channels for oil and gas leakage. At the same time, when using cement materials for plugging, it is necessary to completely remove the ground oil production equipment and completely take out the oil pipes at the bottom of the well before injecting cement. This process is relatively complicated and requires a long period of preparation in the early stages.

[0004] Moreover, when cement is used to seal abandoned wells, it takes a long time for the cement material to be completely solidified from the beginning of injection, and during the solidification process, it is impossible to intervene manually, so the sealing effect cannot be controlled. In addition, since the cement material itself is not a completely dense material, there may be certain defects such as pores in the formed plug, which will affect its airtight sealing effect. Based on the above considerations, for the sealing of abandoned wells, a construction plan and sealing material with low operating cost, simple construction, high airtight effect, stability, reliability, and corrosion resistance is needed. Summary of the invention

[0005] In view of the above problems, the present invention provides an abandoned well plugging device, including an abandoned well and a plugging body for plugging the abandoned well, the plugging body including a plugging column, the outer wall of the plugging column is provided with a sealing block, an anchor block and a plugging alloy in sequence along its own vertical center line, the plugging column is connected to a heating structure for melting the plugging alloy, the melted plugging alloy contacts with the sealing block to form a sealing layer, the sealing block includes a metal cone and an expansion rubber plug mounted on the plugging column, the expansion rubber plug is provided with a metal cone in contact with the plugging body, and the end of the expansion rubber plug passes through the metal cone and extends outward.

[0006] Furthermore, a chamfer is provided on the outer wall of the anchor block, a mounting buckle is provided on a side of the anchor block close to the blocking column, and an extension buckle engaged with the mounting buckle is provided on the blocking column.

[0007] Furthermore, a transverse horizontal line of the mounting buckle is higher than a horizontal line of the extension buckle.

[0008] Furthermore, the blocking column includes a column body and a fastening bolt arranged in sequence along its own vertical center line, a threaded hole is provided at one end of the column body, a fastening bolt is threadedly connected in the threaded hole, the head diameter of the fastening bolt is larger than the diameter of the column body, and an accommodating hole for accommodating a heating structure is provided at the other end of the column body, and the heating structure is connected to the column body.

[0009] Furthermore, the heating structure is provided with an activator, a heating tube and a fixed shell in sequence spreading outward along the vertical center line, the portion of the heating tube away from the fixed shell is accommodated in a accommodating hole, a heat source in contact with the working end of the activator is provided in the heating tube, and the open end of the fixed shell is in contact with an end of the column away from the fastening bolt.

[0010] Furthermore, a connecting groove is provided between the heating cylinder and the fixed shell, a connecting body accommodated in the connecting groove is provided on the column, and a shearing piece penetrating the fixed shell is provided on the connecting body.

[0011] Furthermore, a shearing piece for limiting the position of the heating tube is provided near the end of the column.

[0012] Furthermore, a support plate is provided on the column, and the support plate is used as a horizontal dividing point. A sealing alloy in contact with the support plate is provided at a position of the column close to the heating structure, and one end of the support plate away from the sealing alloy is in contact with the end of the anchor block, and the extension buckle is arranged at a position of the column close to the fastening bolt.

[0013] Furthermore, a lowering device is connected to the fixed shell via a steel rope, and the lowering device is electrically connected to the exciter.

[0014] The method for using the abandoned well plugging device comprises the following steps:

[0015] Using the lowering device to lower the plugging body into the abandoned well;

[0016] The plugging column is lifted by the lowering device to make the expansion rubber plug expand radially and fit tightly with the abandoned well wall.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 1) The invention has the advantages of simple construction, low operation cost, high air-tightness effect, stability and reliability, and corrosion resistance.

[0019] 2) The present invention forms a sealed solid layer by melting the plugging alloy, so it can adapt to different well diameters and complete the plugging of abandoned wells, and the operation method is simple.

[0020] 3) The metal alloy and the casing in the present invention have similar material properties, and the bonding surface strength of the two is relatively high, which can well resist the creep caused by the ground stress at the bottom of the well.

[0021] Other features and advantages of the present invention will be described in the following description, and partly become apparent from the description, or understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures pointed out in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of the structure of an embodiment of the present invention is shown;

[0024] Figure 2 Shows Figure 1 A partial enlarged view of middle A;

[0025] Figure 3 Shows Figure 1 A partial enlarged view of B in the middle;

[0026] Figure 4 A schematic diagram showing a shearing piece embedded in a column;

[0027] Figure 5 The schematic diagram of the structure after the packing block is expanded is shown;

[0028] Figure 6 Shows Figure 5 A partial enlarged view of middle C;

[0029] Figure 7 A schematic diagram showing the connection between the connector and the fixed shell;

[0030] Figure 8 Shows Figure 7 A partial enlarged view of D in the middle;

[0031] Fig. 9 A schematic diagram showing the placement of the plugging body into an abandoned well;

[0032] Fig.10 A schematic diagram showing a packing block being squeezed by an anchor block;

[0033] Fig.11 A schematic diagram showing the plugging alloy melting and moving down to the packing block;

[0034] Fig.12 A schematic diagram showing a heating structure protruding from an open hole wall;

[0035] Figure numerals: 1. Sealing column; 11. Column; 111. Threaded hole; 112. Accommodating hole; 113. Extension buckle; 114. Support plate; 115. Connecting hole; 116. Shear piece; 117. Connecting body; 2. Fastening bolt; 3. Sealing block; 31. Metal cone; 32. Expansion plug; 4. Anchor block; 41. Chamfer; 42. Mounting buckle; 5. Sealing alloy; 6. Heating structure; 61. Heating cylinder; 62. Heat source; 63. Excitation medicine; 64. Exciter; 65. Fixed shell; 651. Fixed ring; 66. Connecting groove; 7. Steel rope; 8. Running device; 81. Winch; 82. Control end; 9. Sealing layer; 10. Open hole wall; 101. Cement ring; 102. Casing. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] Figure 1 FIG. 2 shows a schematic diagram of a structure according to an embodiment of the present invention. Figure 1 As shown, a plugging device for an abandoned well includes an abandoned well and a plugging body for plugging the abandoned well, the plugging body includes a plugging column 1, the outer wall of the plugging column 1 is provided with a sealing block 3, an anchor block 4, and a plugging alloy 5 in sequence along its own vertical center line, the plugging column 1 is connected to a heating structure 6 for melting the plugging alloy 5, the melted plugging alloy 5 is in contact with the plugging block 3 to form a sealing layer 9, the sealing block 3 includes a metal cone 31 and an expansion plug 32 sleeved on the plugging column 1, the expansion plug 32 is sleeved with a metal cone 31 in contact with the plugging body, and the end of the expansion plug 32 passes through the metal cone 31 and extends outward.

[0038] The wellbore plugging device utilizes a heating structure 6 to melt the plugging alloy 5 around the plugging column 1. The melted plugging alloy 5 moves downward along the plugging column 1, accumulates and solidifies on the deformed isolation block 3, and bonds with the abandoned wellbore wall, thereby forming a dense sealing layer 9. The sealing layer 9 has good airtightness, is stable and reliable, and is corrosion-resistant. The entire device is simple to construct.

[0039] Figure 5 FIG. 3 shows a schematic diagram of the structure of the packing block 3 after expansion. Figure 5 As shown, in some embodiments, one end of the anchor block 4 away from the blocking alloy 5 contacts the end of the metal cone 31; the anchor block 4 can quickly squeeze the metal cone 31, and the metal cone 31 then transmits the squeezing force to the expansion plug 32, thereby achieving the purpose of uniform expansion of the expansion plug 32.

[0040] In some embodiments, the width of the expansion plug 32 is wider than the width of the metal cone 31; after being squeezed, the metal cone 31 will uniformly squeeze the expansion plug 32 to make it expand radially. Under the premise that the width of the expansion plug 32 is wider than the width of the metal cone 31, the expansion plug 32 will accelerate the contact with the wall of the abandoned well, providing landing conditions for the melted sealing alloy 5.

[0041] In some embodiments, the transverse centerline of the metal cone 31 is coaxial with the transverse centerline of the expansion plug 32, which can ensure that the expansion plug 32 expands uniformly in the radial direction after being squeezed.

[0042] Figure 2 Shows Figure 1 A partial enlarged view of the figure. Figure 2 As shown, in some embodiments, a chamfer 41 is provided on the outer wall of the anchor block 4, a mounting buckle 42 is provided on the side of the anchor block 4 close to the blocking column 1, and an extension buckle 113 engaged with the mounting buckle 42 is provided on the blocking column 1; after the blocking body is lowered into the abandoned well, the chamfer 41 generates friction with the wall of the abandoned well, and the resistance is small when the blocking body moves downward, and the resistance increases when the blocking body is lifted, so that the anchor block 4 does not move when the blocking body is lifted, and when the blocking body is lifted, the mounting buckle 42 is engaged with the extension buckle 113, which can prevent the anchor block 4 from moving upward relative to the blocking body.

[0043] Specifically, the chamfer 41 can increase the pulling resistance of the metal cone 31 and the expansion plug 32 so that the shearing piece 116 can be sheared successfully, and can also slow down the dripping speed of the melting sealing alloy 5 to avoid melting the expansion plug 32 .

[0044] Specifically, the chamfer 41 may be made of, but not limited to, glass fiber, zirconia, and other materials.

[0045] Figure 6 Shows Figure 5 A partial enlarged view of C in the figure. Figure 6 As shown, in some embodiments, the installation buckle 42 and the working end of the extension buckle 113 are arranged in opposite directions; only when the directions are opposite can the two be engaged and the position of the blocking column 1 in the abandoned well be fixed.

[0046] In some embodiments, the transverse horizontal line of the mounting buckle 42 is higher than the horizontal line of the extension buckle 113, which determines the expansion degree of the expansion plug 32; the distance between the mounting buckle 42 and the extension buckle 113 is the critical distance for the anchor block 4 and the head of the fastening bolt 2 to squeeze the isolation block 3.

[0047] In some embodiments, the blocking column 1 includes a column 11 and a fastening bolt 2 which are arranged in sequence along its vertical center line. A threaded hole 111 is provided at one end of the column 11. The fastening bolt 2 is threadedly connected to the threaded hole 111. The head diameter of the fastening bolt 2 is larger than the diameter of the column 11. A receiving hole 112 for receiving a heating structure 6 is provided at the other end of the column 11. The heating structure 6 is connected to the column 11. The fastening bolt 2 can limit the axial displacement of the sealing block 3. Placing the heating structure 6 in the receiving hole 112 can transfer the temperature of the heating structure 6 to the blocking alloy 5 through the column 11, thereby achieving a melting effect and saving space.

[0048] In some embodiments, the heating structure 6 is provided with an exciter 64, a heating tube 61, and a fixed shell 65 diffused outward in sequence along the vertical center line. The portion of the heating tube 61 away from the fixed shell 65 is accommodated in the accommodating hole 112. A heat source 62 in contact with the working end of the exciter 64 is provided in the heating tube 61, and the open end of the fixed shell 65 is in contact with an end of the column 11 away from the fastening bolt 2; the exciter 64 is used to excite the heat source 62, generate high temperature, and transmit it to the sealing alloy 5 through the column 11. After the sealing alloy 5 melts, it moves down to the deformed isolation block 3 and bonds with the wall of the abandoned well, thereby forming a dense sealing layer 9.

[0049] Specifically, the heat source 62 may be selected from but not limited to thermite and electric heating rod.

[0050] Specifically, when thermite is selected as the heat source 62, it is made in the form of cylindrical blocks, the purpose of which is to adjust the filling according to the length of the device, and the burning speed and heat release of the heat source 62 can be changed by the density and diameter of the pressed medicine, thereby providing different degrees of heat source 62 and burning speed requirements.

[0051] Specifically, when the heat source 62 is made of thermite, an excitation agent 63 needs to be provided on the surface, and the excitation agent 63 contacts the working end of the exciter 64 so as to ignite the heat source 62 .

[0052] Figure 7 FIG. 1 is a schematic diagram showing the connection between the connector 117 and the fixed housing 65. Figure 7As shown, in some embodiments, a connecting groove 66 is provided between the heating tube 61 and the fixed shell 65, a connector 117 accommodated in the connecting groove 66 is provided on the column 11, and a shearing piece 116 penetrating the fixed shell 65 is provided on the connector 117; the connecting groove 66 provides a connecting space for the connector 117, and when the lifting force of the column 11 is greater than the shearing force of the shearing piece 116, the heating structure 6 is lifted out of the column 11 to facilitate subsequent manual processing of the heating structure 6.

[0053] Figure 8 Shows Figure 7 A partial enlarged view of D in the figure. Figure 8 As shown, in some embodiments, the connecting body 117 is provided with a connecting hole 115 penetrating the fixing shell 65 , and the shearing piece 116 is disposed in the connecting hole 115 ; the connecting hole 115 facilitates the installation of the shearing piece 116 .

[0054] Figure 3 Shows Figure 1 A partial enlarged view of B. Figure 3 As shown, in some embodiments, a shear piece 116 is provided near the end of the column 11 to limit the position of the heating tube 61; when the lifting force of the column 11 is greater than the shear force of the shear piece 116, the shear piece 116 is cut off, and the heating structure 6 is lifted out of the column 11 to facilitate subsequent manual processing of the heating structure 6.

[0055] Specifically, the shear member 116 may be selected from but is not limited to a pin.

[0056] Figure 4 FIG. 1 shows a schematic diagram of a shearing member 116 embedded in the column 11. Figure 4 As shown, in some embodiments, the shearing piece 116 is embedded in the contact point between the column 11 and the heating tube 61 ; when the lifting force of the column 11 is greater than the shearing force of the shearing piece 116 , the shearing piece 116 retracts and the heating structure 6 is lifted out of the column 11 .

[0057] Specifically, the shear member 116 may be selected from but not limited to a spring plug.

[0058] In some embodiments, a support plate 114 is provided on the column 11, and the support plate 114 is used as a horizontal dividing point. A sealing alloy 5 in contact with the support plate 114 is provided at a position of the column 11 close to the heating structure 6. One end of the support plate 114 away from the sealing alloy 5 is in contact with the end of the anchor block 4. The extended buckle 113 is arranged at a position of the column 11 close to the fastening bolt 2. One end of the support plate 114 supports the sealing alloy 5, and the other end provides resistance to the anchor block 4 to squeeze the sealing block 3.

[0059] Specifically, a basic sealing ring may be provided at the connection between the shearing piece 116 and the column 11 and the fixed shell 65 to ensure sealing.

[0060] In some embodiments, the fixed shell 65 is connected to a lowering device 8 via a steel rope 7, and the lowering device 8 is electrically connected to the activator 64; the sealing body is lowered into the abandoned well using the lowering device 8 and the steel rope 7, and after the sealing layer 9 is formed, the heating structure 6 is lifted out using the lowering device 8; the lowering device 8 can control the switch of the activator 64.

[0061] In some embodiments, a fixing ring 651 is provided on the fixing shell 65 , and the steel rope 7 is connected to the fixing ring 651 .

[0062] In some embodiments, the lowering device 8 includes a winch 81 and a control end 82, the winch 81 is electrically connected to the control end 82, and the exciter 64 is electrically connected to the control end 82; the control end 82 controls the opening and closing of the winch 81 and the exciter 64, thereby realizing the operation of the winch 81 and the exciter 64.

[0063] Specifically, the winch 81 and the exciter 64 are connected to the control terminal 82 via cables.

[0064] Specifically, the control terminal 82 may be selected but not limited to a vehicle-mounted control console.

[0065] Specifically, the winch 81 and the vehicle-mounted control console are prior art and will not be described in detail here.

[0066] Specifically, the steel rope 7 is prior art, so it will not be described in detail here.

[0067] In some embodiments, the abandoned well includes an open hole well wall 10 , a cement ring 101 is arranged inside the open hole well wall 10 , a casing 102 is arranged on the inner wall of the cement ring 101 , and a plugging body is arranged inside the casing 102 .

[0068] The working principle of the wellbore plugging device is as follows:

[0069] By melting the sealing alloy 5, a sealing layer 9 with good airtightness and corrosion resistance is formed. Fig. 9 The schematic diagram of the plugging body placed in the abandoned well is shown in FIG. Fig. 9 As shown, the steel rope 7 on the winch 81 is connected to the fixed ring 651, and then the winch 81 is controlled by the control end 82 to release the rope, so that the plugging body falls into the casing 102 until it reaches the position to be plugged. Fig.10 FIG. 4 shows a schematic diagram of the packing block 3 being squeezed by the anchor block 4. Fig.10As shown, the blocking column 1 is lifted up by the winch 81 so that the metal cone 31 evenly squeezes the expansion plug 32, causing the expansion plug 32 to expand radially and fit tightly with the wall of the casing 102. In the process of lifting the blocking column 1, after the blocking column 1 rises to the preset position, the installation buckle 42 on the anchor block 4 and the extension buckle 113 of the blocking column 1 are buckled, and the chamfer 41 on the anchor block 4 generates friction with the wall of the casing 102, so that the position of the anchor block 4 remains unchanged, and the isolation block 3 always maintains radial expansion and contacts with the wall of the casing 102. Fig.11 FIG. 4 shows a schematic diagram of the plugging alloy 5 being melted and moved down to the packing block 3. Fig.11 As shown, the activator 64 is started through the control end 82 to ignite the heat source 62. After the reaction, the temperature of the heat source 62 is ≧300°C, and the temperature is transferred to the sealing alloy 5 through the sealing column 1. The melted sealing alloy 5 moves down along the sealing column 1, accumulates and solidifies on the metal cone 31 and the expansion plug 32, and is bonded to the wall of the casing 102, thereby forming a dense sealing layer 9. Fig.12 A schematic diagram showing the heating structure 6 protruding from the borehole wall 10 is shown. Fig.12 As shown, since the plugging column 1 is fixed in the casing 102 by the anchor block 4, the steel rope 7 on the winch 81 is connected to the fixing ring 651. Therefore, after the sealing is completed, the fixing ring 651 is continuously lifted by the winch 81. When the lifting force of the heating structure 6 is greater than the shear force of the shear member 116, the exciter 64 and the heating tube 61 are lifted out of the open hole wall 10, thereby completing the plugging of the abandoned well.

[0070] The melted plugging alloy 5 is deposited circumferentially on the sealing block 3 and is bonded to the wall of the casing 102, so that the sealing layer 9 formed is stable and reliable. Based on the alloy material properties of the sealing layer 9, the sealing layer 9 has the characteristics of high airtightness and corrosion resistance.

[0071] Specifically, the material of the shearing piece 116 may be, but is not limited to, brass.

[0072] Specifically, the plugging alloy 5 may be selected from but not limited to a tin-based alloy, the melting temperature of which is between 300° C. and 400° C. Since the tin-based alloy is a prior art, it will not be described in detail here.

[0073] Specifically, the material of the column 11 may be selected but not limited to 42CrMo steel.

[0074] Specifically, the expansion plug 32 may be made of, but is not limited to, rubber.

[0075] Specifically, the plugging body is also applicable to the open hole well wall 10.

[0076] A method for using an abandoned well plugging device comprises the following steps:

[0077] Fix the position of the winch 81, connect the steel rope 7 on the winch 81 to the fixing ring 651, and control the winch 81 to release the rope through the control end 82, so that the plugging body is slowly lowered to the target position in the abandoned well;

[0078] Then, the control end 82 controls the winch 81 to retract the rope, and lifts the plugging column 1 upward to a certain position, so that the installation buckle 42 is buckled with the extension buckle 113, and the sealing block 3 is squeezed by the anchor block 4 and the head of the fastening bolt 2, and the metal cone 31 transmits the squeezing force to the expansion plug 32, so that the expansion plug 32 expands evenly and fits tightly to the wall of the abandoned well;

[0079] Then, the control end 82 controls the operation of the activator 64, so that the activator 64 activates the heating cylinder 61 to react the heat source 62, releases heat to the column 11 and transmits it to the plugging alloy 5, and the melted plugging alloy 5 moves down to the deformed sealing block 3 and bonds with the wall of the casing 102 to form a dense sealing layer 9;

[0080] Then, the control end 82 controls the winch 81 to retract the rope, so that the lifting force of the heating structure 6 is greater than the shear force of the shearing member 116, and the heating structure 6 is lifted out of the abandonment well;

[0081] An evaluation experiment of the abandoned well sealing layer 9 is conducted according to any one of the "Specifications for Backfilling of Permanently Abandoned Wells", "API SPEC 11D1 4TH ED(2021)" and "ISO 14310-2008(2)".

[0082] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein; and these modifications or substitutions do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An abandoned well plugging device, comprising an abandoned well, characterized in that: It also includes a plugging body for plugging abandoned wells, the plugging body including a plugging column (1), the outer wall of the plugging column (1) being provided with a sealing block (3), an anchor block (4), and a plugging alloy (5) in sequence along its own vertical center line, the plugging column (1) being connected with a heating structure (6) for melting the plugging alloy (5), the molten plugging alloy (5) being in contact with the plugging block (3) to form a sealing layer (9), the plugging block (3) comprising a metal cone (31) and an expansion rubber plug (32) sleeved on the plugging column (1), the expansion rubber plug (32) being sleeved with a metal cone (31) in contact with the plugging body, the end of the expansion rubber plug (32) passing through the metal cone (31) and extending outward.

2. The abandoned well plugging device according to claim 1, characterized in that: The outer wall of the anchor block (4) is provided with a chamfer (41), a side of the anchor block (4) close to the blocking column (1) is provided with a mounting buckle (42), and the blocking column (1) is provided with an extension buckle (113) that is engaged with the mounting buckle (42).

3. The abandoned well plugging device according to claim 2, characterized in that: The transverse horizontal line of the installation buckle (42) is higher than the horizontal line of the extension buckle (113).

4. The abandoned well plugging device according to claim 2, characterized in that: The blocking column (1) comprises a column (11) and a fastening bolt (2) which are arranged in sequence along its own vertical center line; one end of the column (11) is provided with a threaded hole (111); the threaded inner hole (111) is threadedly connected with the fastening bolt (2); the head diameter of the fastening bolt (2) is larger than the diameter of the column (11); the other end of the column (11) is provided with a receiving hole (112) for receiving a heating structure (6); the heating structure (6) is connected to the column (11).

5. The abandoned well plugging device according to claim 4, characterized in that: The heating structure (6) is provided with an exciter (64), a heating tube (61), and a fixed shell (65) in sequence and spread outward along the vertical center line; a portion of the heating tube (61) away from the fixed shell (65) is accommodated in an accommodation hole (112); a heat source (62) in contact with a working end of the exciter (64) is provided in the heating tube (61); and an open end of the fixed shell (65) is in contact with an end of the column (11) away from the fastening bolt (2).

6. The abandoned well plugging device according to claim 5, characterized in that: A connecting groove (66) is provided between the heating tube (61) and the fixed shell (65), a connecting body (117) accommodated in the connecting groove (66) is provided on the column (11), and a shearing piece (116) penetrating the fixed shell (65) is provided on the connecting body (117).

7. The abandoned well plugging device according to claim 5, characterized in that: A shearing piece (116) for limiting the position of the heating cylinder (61) is provided near the end of the column (11).

8. The abandoned well plugging device according to claim 5, characterized in that: The column (11) is provided with a support plate (114), and the support plate (114) is used as a transverse dividing point. A portion of the column (11) close to the heating structure (6) is provided with a blocking alloy (5) in contact with the support plate (114), and one end of the support plate (114) away from the blocking alloy (5) is in contact with the end of the anchor block (4), and the extension buckle (113) is arranged at a portion of the column (11) close to the fastening bolt (2).

9. The abandoned well plugging device according to claim 5, characterized in that: The fixed shell (65) is connected to a lowering device (8) via a steel rope (7), and the lowering device (8) is electrically connected to the exciter (64).

10. A method for using an abandoned well plugging device, characterized in that: The wellbore plugging device according to any one of claims 1 to 9 comprises the following steps: Using a lowering device (8) to lower the plugging body into the abandoned well; The plugging column (1) is lifted by the lowering device (8) to make the expansion rubber plug (32) expand radially and fit tightly with the abandoned well wall; The activator (64) is controlled by the lowering device (8) to activate the heat source (62) to react and melt the plugging alloy (5); the melted plugging alloy (5) moves downward onto the deformed isolation block (3) and bonds with the abandoned well wall to form a dense sealing layer (9); Using a lowering device (8), the heating structure (6) is lifted out of the abandonment well; An evaluation experiment of the abandoned well sealing layer (9) was conducted.

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