Complete adjustment well sealing device and pressure control well drilling empty and measuring working condition wellhead sealing method

Abstract

The invention relates to the technical field of well drilling well control processes, in particular to a well sealing perfecting and adjusting device and a pressure control well drilling empty and measuring working condition wellhead sealing method. The sealing device comprises a sealer and a rotary blowout preventer, the lower end of the sealer is connected with the rotary blowout preventer, the sealer and the rotary blowout preventer are sealed through a rotary blowout preventer sealing piece, and a rotary blowout preventer hoop hydraulic cylinder is installed on the side face of the upper end of the rotary blowout preventer. The sealer comprises a shell, a rubber core is arranged on the inner side of the upper portion of the shell, a sealer inner cavity is formed in the inner side of the rubber core, the lower portion of the rubber core is connected with a hydraulic cylinder mechanism, and the shell and the sealer inner cavity are sealed through a shell sealing piece. According to the sealing device for perfecting and adjusting the well and the wellhead sealing method for the pressure-controlled drilling empty and measuring working conditions, the technical defects of a pressure-controlled drilling technology under the empty and measuring working conditions can be overcome, the pressure-controlled technology under the empty and measuring working conditions can be further achieved, and the drilling cost is saved.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling well control technology, and in particular to a method for improving and adjusting a well sealing device and a wellhead sealing method for pressure-controlled drilling and measuring working conditions. Background Art

[0002] At present, the existing controlled pressure drilling process mostly adopts passive sealing assemblies, which can realize wellhead sealing and pressure control of drilling, single root connection, tripping and completion processes. However, in actual production, the passive sealing assembly has no way to seal and control the pressure of the wellhead during empty well and cable logging conditions. In practical applications, most adjustment wells cannot be installed with annular blowout preventers and fully sealed gate blowout preventers due to the limitation of their base height. If the adjustment well has downhole fluid intrusion under empty and testing conditions, the treatment method will be very passive. Generally speaking, in order to prevent downhole fluid intrusion, a lot of time will be used to treat the drilling fluid before empty and testing conditions, such as weighting and post-testing operations, but this practice will increase the risk of well leakage and operating costs of the adjustment well. Therefore, in view of the above shortcomings, a method for improving the sealing device of the adjustment well and the wellhead sealing method of the empty and testing conditions of controlled pressure drilling is proposed. Summary of the invention

[0003] 1. Technical issues to be resolved The present invention provides a perfect adjustment well sealing device and a wellhead sealing method for controlled pressure drilling empty and logging conditions, so as to overcome the problems in the prior art of being unable to seal and control the wellhead pressure during empty well and cable logging conditions due to technical shortcomings of the controlled pressure drilling process under empty well and logging conditions, resulting in an increase in the risk of well leakage and an increase in operating costs.

[0004] (II) Technical solution In order to solve the above problems, the present invention provides a perfect adjustment well sealing device, comprising: A sealer and a rotary blowout preventer, wherein the lower end of the sealer is connected to the rotary blowout preventer, the sealer and the rotary blowout preventer are sealed by a rotary blowout preventer seal, and a rotary blowout preventer clamp fluid cylinder is installed on the side of the upper end of the rotary blowout preventer; the sealer comprises a shell, the inner side above the shell is a rubber core, the inner side of the rubber core is a sealer inner cavity, the lower side of the rubber core is connected to a fluid cylinder mechanism, and the shell and the sealer inner cavity are sealed by a shell seal.

[0005] Preferably, the cylinder mechanism comprises a cylinder open, a cylinder body, a cylinder close, a cylinder sleeve and a cylinder inner cavity, the inner side of the cylinder open is connected to the cylinder inner cavity, the outer side of the cylinder inner cavity is the cylinder body, the outer side of the cylinder body is sleeved with the cylinder sleeve, and the bottom of the cylinder body is connected to the cylinder close.

[0006] Preferably, the liquid cylinder opening is horizontally installed inside the sealer, and the outer side of the liquid cylinder opening is connected to the shell.

[0007] Preferably, the liquid cylinder switch is horizontally installed inside the sealer, and the outer side of the liquid cylinder switch is connected to the shell.

[0008] Preferably, the shell is a rubber core shell, and the shell includes four parts, namely a truncated cone structure, a first cylinder, a second cylinder and a third cylinder. The truncated cone structure is connected to the first cylinder, the first cylinder is connected to the second cylinder, and the second cylinder is connected to the third cylinder.

[0009] Preferably, the truncated cone structure includes a first circular bottom surface and a second circular bottom surface, the diameter of the first circular bottom surface is smaller than the diameter of the second circular bottom surface, the diameter of the second circular bottom surface is smaller than the bottom diameter of the first cylinder, the bottom diameter of the first cylinder is smaller than the bottom diameter of the second cylinder, the bottom diameter of the second cylinder is larger than the bottom diameter of the third cylinder, and the bottom diameter of the first cylinder is equal to the bottom diameter of the third cylinder.

[0010] Preferably, the rubber core is a spherical rubber core, the inner curvature of the truncated cone structure can match the spherical rubber core, and a plurality of eye screws are installed on the top of the truncated cone structure, and the spacing between the plurality of eye screws is equal.

[0011] Preferably, the truncated cone structure and the first cylinder are connected via a plurality of housing cylinder head nuts, and the distances between the plurality of housing cylinder head nuts are equal.

[0012] Another aspect of the present invention provides a wellhead sealing method for an empty well condition of a controlled pressure drilling well to improve the well sealing device, comprising: Step S1: determine the target adjustment well, connect the sealing device, and fix the sealer with a clamp; Step S2: Observe whether the adjustment well has downhole fluid invasion. If not, apply a safe wellhead back pressure to the adjustment well according to the formation fracture pressure test data to suppress the invasion of downhole fluid; Step S3: Based on the observations in step S2, if the adjustment well is intruded by underground fluid, the hydraulic cylinder mechanism is closed by the hydraulic pump station, and the hydraulic oil enters the inner cavity of the hydraulic cylinder through the channel of the hydraulic cylinder closure, pushing the cylinder body to move upward, and through the action of the cylinder body and the shell, the rubber core is squeezed and deformed until the wellhead is sealed, and the pressure is controlled by the hydraulic pump station according to the actual situation underground; Step S4: After completing step S3, adjust the pressure-controlled back pressure pump or the well team variable frequency pump to apply back pressure to the bottom of the well by rotating the side outlet of the blowout preventer.

[0013] In another aspect, the present invention provides a wellhead sealing method for improving the pressure-controlled drilling and logging working conditions of the well sealing device, comprising: Step S1: determine the target adjustment well, connect the sealing device, and fix the sealer with a clamp; Step S2: Observe whether the adjustment well has downhole fluid intrusion. If downhole fluid intrusion occurs, the hydraulic cylinder mechanism is closed by the hydraulic pump station, and the hydraulic oil enters the inner cavity of the hydraulic cylinder through the channel of the hydraulic cylinder closure, pushing the cylinder body to move upward. Through the action of the cylinder body and the shell, the rubber core is squeezed and deformed until the logging cable is sealed, thereby achieving the sealing of the wellhead logging cable and the instrument; Step S3: After completing step S2, the pressure of the hydraulic cylinder closing pressure is adjusted to cope with different bottom hole pressure conditions, and then the logging instrument is pulled out of the wellhead under pressure to achieve safe operation.

[0014] (III) Beneficial effects The improved adjustment well sealing device and the wellhead sealing method for pressure controlled drilling empty and measuring conditions provided by the present invention will greatly assist the whole process of pressure controlled drilling and cost reduction and efficiency improvement. Through the sealing device and control method, the pressure control process under empty and measuring conditions can be realized, which makes up for the technical shortcomings, saves drilling costs, and lays the foundation for the technical solution of the pressure controlled drilling promotion and application project. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A schematic diagram of the structure of the well sealing device for improving the embodiment of the present invention; Figure 2 Schematic diagram of the structure of the sealer according to the embodiment of the present invention.

[0016] Legend: 1-seal; 2-rotating blowout preventer; 3-rotating blowout preventer clamp cylinder; 4-rotating blowout preventer seal; 5-lifting eye screw; 6-housing; 7-rubber core; 8-cylinder open; 9-cylinder body; 10-cylinder close; 11-housing seal; 12-seal cavity; 13-housing cylinder head nut; 14-cylinder liner; 15-cylinder cavity. Implementation

[0017] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only 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.

[0018] Figure 1 The structural diagram of the well sealing device is improved and adjusted according to the embodiment of the present invention. Figure 2 Schematic diagram of the structure of the sealer according to the embodiment of the present invention. Figure 1 and Figure 2 As shown, the present invention provides a perfect adjustment well sealing device, comprising: A sealer 1 and a rotary blowout preventer 2, wherein the lower end of the sealer 1 is connected to the rotary blowout preventer 2, the sealer 1 and the rotary blowout preventer 2 are sealed by a rotary blowout preventer sealer 4, and a rotary blowout preventer clamp fluid cylinder 3 is installed on the side of the upper end of the rotary blowout preventer 2; the sealer 1 comprises a shell 6, the inner side of the upper part of the shell 6 is a rubber core 7, the inner side of the rubber core 7 is a sealer inner cavity 12, the lower part of the rubber core 12 is connected to a fluid cylinder mechanism, and the shell 6 and the sealer inner cavity 12 are sealed by a shell sealer 11.

[0019] In actual application, the hydraulic cylinder mechanism includes a hydraulic cylinder opening 8, a hydraulic cylinder body 9, a hydraulic cylinder close 10, a cylinder sleeve 14 and a hydraulic cylinder inner cavity 15. The inner side of the hydraulic cylinder opening 8 is connected to the hydraulic cylinder inner cavity 15, the outer side of the hydraulic cylinder inner cavity 15 is the hydraulic cylinder body 9, the outer side of the hydraulic cylinder body 9 is sleeved with the cylinder sleeve 14, and the bottom of the hydraulic cylinder body 14 is connected to the hydraulic cylinder close 10.

[0020] It should be noted that the positional relationship between the hydraulic cylinder opening 8 and the hydraulic cylinder closing 10 is a parallel relationship. The hydraulic cylinder opening 8 is horizontally installed inside the sealer 2, and the outer side of the hydraulic cylinder opening 8 is connected to the shell 6; the hydraulic cylinder closing 10 is horizontally installed inside the sealer 2, and the outer side of the hydraulic cylinder closing 10 is connected to the shell 6.

[0021] In this sealing device, the shell 6 is a rubber core shell, which includes four parts, namely a truncated cone structure, a first cylinder, a second cylinder and a third cylinder. The truncated cone structure connects the first cylinder, the first cylinder connects the second cylinder, and the second cylinder connects the third cylinder.

[0022] In practical applications, the truncated cone structure includes a first circular bottom surface and a second circular bottom surface, the diameter of the first circular bottom surface is smaller than the diameter of the second circular bottom surface, the diameter of the second circular bottom surface is smaller than the bottom diameter of the first cylinder, the bottom diameter of the first cylinder is smaller than the bottom diameter of the second cylinder, the bottom diameter of the second cylinder is larger than the bottom diameter of the third cylinder, and the bottom diameter of the first cylinder is equal to the bottom diameter of the third cylinder.

[0023] It should be noted that the rubber core 7 is a spherical rubber core, the internal curvature of the truncated cone structure can match the spherical rubber core, a plurality of eye screws 5 are installed on the top of the truncated cone structure, and the spacing between the plurality of eye screws 5 is equal. In addition, the truncated cone structure and the first cylinder are connected by a plurality of shell cylinder head nuts 13, and the distances between the plurality of shell cylinder head nuts 13 are equal.

[0024] The present invention also provides a wellhead sealing method for a controlled pressure drilling empty well condition based on a perfect adjustment well sealing device, comprising: Step S1: determine the target adjustment well, connect the sealing device, and fix the sealer with a clamp; Step S2: Observe whether the adjustment well has downhole fluid invasion. If not, apply a safe wellhead back pressure to the adjustment well according to the formation fracture pressure test data to suppress the invasion of downhole fluid; Step S3: Based on the observations in step S2, if the adjustment well is intruded by underground fluid, the hydraulic cylinder mechanism is closed by the hydraulic pump station, and the hydraulic oil enters the inner cavity of the hydraulic cylinder through the channel of the hydraulic cylinder closure, pushing the cylinder body to move upward, and through the action of the cylinder body and the shell, the rubber core is squeezed and deformed until the wellhead is sealed, and the pressure is controlled by the hydraulic pump station according to the actual situation underground; Step S4: After completing step S3, adjust the pressure-controlled back pressure pump or the well team variable frequency pump to apply back pressure to the bottom of the well by rotating the side outlet of the blowout preventer.

[0025] The present invention also provides a wellhead sealing method for a controlled pressure drilling and logging condition based on a perfect adjustment well sealing device, comprising: Step S1: determine the target adjustment well, connect the sealing device, and fix the sealer with a clamp; Step S2: Observe whether the adjustment well has downhole fluid intrusion. If downhole fluid intrusion occurs, the hydraulic cylinder mechanism is closed by the hydraulic pump station, and the hydraulic oil enters the inner cavity of the hydraulic cylinder through the channel of the hydraulic cylinder closure, pushing the cylinder body to move upward. Through the action of the cylinder body and the shell, the rubber core is squeezed and deformed until the logging cable is sealed, thereby achieving the sealing of the wellhead logging cable and the instrument; Step S3: After completing step S2, the pressure of the hydraulic cylinder closing pressure is adjusted to cope with different bottom hole pressure conditions, and then the logging instrument is pulled out of the wellhead under pressure to achieve safe operation.

[0026] It should be noted that the adjustment well is limited by the height of the drilling platform and only half-closed gates are installed. Before the empty and test conditions, the post-test operation should be carried out, and the drilling fluid should be gradually increased until the safe production operation time is met. If equipment failure is found, it is necessary to pull the drill to the ground for equipment inspection, and the weight should also be increased in advance. Sometimes it is impossible to verify the safe operation time and the drilling fluid density can only be increased to the upper limit or even higher. The agitated pressure during drilling may cause well leakage accidents. If the sealing device is installed at the wellhead and the pressure is adjusted to seal the wellhead before the empty and test conditions, back pressure can be applied to the annulus, which can balance the bottom hole pressure and avoid the increase in cost and construction period due to the consideration of safe production time.

[0027] In practical applications, the size of the rubber core 7 is not less than 100 mm, and it can easily pass through various types of logging instruments. It can realize the application of wellhead back pressure during the logging process, and can also quickly seal the wellhead and pull out the instrument under pressure when downhole fluid intrusion occurs. Under empty well conditions, the sealer 1 is closed, and the wellhead back pressure can be adjusted through the pressure-controlled drilling equipment to balance the formation pressure. The height of the sealer 1 is lower than the rotary blowout preventer assembly, and it can be installed on the rotary blowout preventer 2 through the turntable port. It is easy to install and disassemble. After testing, the pressure control system can form pressure data when instruments and cables of different sizes pass through, and form operating specifications.

[0028] In practical applications, in order to make up for the technical shortcomings of the pressure-controlled drilling process under empty and measuring conditions, and to achieve active sealing of the wellhead and pressure control under these two conditions, and to be able to safely pull the logging cable and instruments out of the wellhead, it is necessary to form a new sealing method and strategy based on the existing rotary blowout preventer. This sealing method uses the existing rotary blowout preventer and pressure system, and uses adjustable pressure to adjust the sealing force of the sealant core, so as to achieve active sealing of the wellhead while allowing the passage of instruments and cables. It can be installed in the wellhead rotary blowout preventer before empty and measuring conditions to achieve the required functions.

[0029] The following describes the actual application of this perfect adjustment well sealing device: In this embodiment, the lower end of the sealer 1 is connected to the rotary blowout preventer 2, the sealer 1 and the rotary blowout preventer 2 are sealed by a rotary blowout preventer seal 4, and a rotary blowout preventer clamp cylinder 3 is installed on the side of the upper end of the rotary blowout preventer 2; the sealer 1 includes a shell 6, the inner side of the upper part of the shell 6 is a rubber core 7, the inner side of the rubber core 7 is a sealer inner cavity 12, and the lower part of the rubber core 12 is connected to a cylinder mechanism, and the cylinder mechanism includes a cylinder opening 8, a cylinder body 9, a cylinder close 10, a cylinder sleeve 14 and a cylinder The inner cavity 15, the inner side of the liquid cylinder opening 8 is connected to the liquid cylinder inner cavity 15, the outer side of the liquid cylinder inner cavity 15 is the liquid cylinder body 9, the outer side of the liquid cylinder body 9 is connected to the cylinder sleeve 14, the bottom of the liquid cylinder body 14 is connected to the liquid cylinder close 10, the liquid cylinder opening 8 is horizontally installed inside the sealer 2, the outer side of the liquid cylinder opening 8 is connected to the shell 6, the liquid cylinder close 10 is horizontally installed inside the sealer 2, the outer side of the liquid cylinder close 10 is connected to the shell 6, and the shell 6 and the sealer inner cavity 12 are sealed by the shell seal 11.

[0030] In actual application, the shell 6 is a rubber core shell, and the shell 6 includes four parts, namely a truncated cone structure, a first cylinder, a second cylinder and a third cylinder. The truncated cone structure connects the first cylinder, the first cylinder connects the second cylinder, and the second cylinder connects the third cylinder. The rubber core 7 is a spherical rubber core. The internal curvature of the truncated cone structure can match the spherical rubber core. Four lifting eye screws 5 are installed on the top of the truncated cone structure, and the spacing between the four lifting eye screws 5 is equal. In addition, the truncated cone structure and the first cylinder are connected by 8 shell cylinder head nuts 13, and the distance between the 8 shell cylinder head nuts 13 is equal.

[0031] In this embodiment, the sealer 1 is divided into two parts, the upper part is the sealing part of the rubber core 7, and the sealing power is provided by the hydraulic cylinder mechanism, which can not only control the opening and closing of the rubber core 7, but also quantitatively adjust the size of the sealing force. The lower part is the sealing part of the sealer 1 and the rotary blowout preventer 2, which is consistent with the assembly structure and can be universal.

[0032] In order to overcome the technical shortcomings of the prior art in the controlled pressure drilling process under empty well and logging conditions, which leads to the inability to seal and control the wellhead pressure during empty well and cable logging conditions, resulting in increased risk of well leakage and increased operating costs, the present invention also provides a wellhead sealing method for empty well conditions and logging conditions in controlled pressure drilling based on a perfect adjustment well sealing device.

[0033] When the drilling process is in an empty well condition, the specific process of the wellhead sealing method is as follows: before the empty well condition, the sealer 1 is installed on the rotary blowout preventer 2, and the sealer 1 is fixed by a clamp; in the empty well condition, the adjustment well is observed, and if downhole fluid intrusion occurs, the hydraulic cylinder mechanism is immediately closed by the hydraulic pump station, and the hydraulic oil enters the inner cavity 15 of the hydraulic cylinder through the channel of the hydraulic cylinder closure 10, pushing the cylinder body 9 to move upward, and through the action of the cylinder body 9 and the shell 6, the rubber core 7 is squeezed and deformed until the wellhead is sealed, and the pressure is controlled by the hydraulic pump station according to the actual downhole conditions, and the pressure range is 0-21MPa; then, according to the controlled pressure drilling process strategy, the controlled pressure back pressure pump or the well team frequency conversion pump is adjusted to apply back pressure to the bottom of the well through the side outlet of the rotary blowout preventer 2; during the empty well condition, if it is observed that no downhole fluid intrusion occurs in the adjustment well, a safe wellhead back pressure can also be applied according to the formation fracture pressure test data to suppress the intrusion of downhole fluid.

[0034] When the drilling process is in the logging condition, the specific process of the wellhead sealing method is as follows: before the logging condition, install the sealer on the rotary blowout preventer 2, and fix the sealer 1 by the clamp; during the logging condition, observe and adjust the well, if downhole fluid intrusion occurs, immediately close the cylinder mechanism through the hydraulic pump station, and the hydraulic oil enters the cylinder cavity 15 through the channel of the cylinder closure 10, pushing the cylinder body 9 to move upward, and through the action of the cylinder body 9 and the shell 6, the rubber core 7 is squeezed and deformed until the logging cable is sealed, so as to achieve the sealing of the wellhead logging cable and the instrument; then, according to the pressure-controlled drilling process strategy, the cylinder mechanism is adjusted to adjust the pressure of the closing pressure to cope with different bottom hole pressure conditions, and then the logging instrument is lifted out of the wellhead under pressure to achieve safe operation.

[0035] In practical applications, the sealing device and method can adjust the wellhead sealing technology of empty and logging conditions in well-controlled pressure drilling, and further realize an adjustable pressure-type rubber core control method. Through the sealing device, the wellhead can be sealed and the wellhead sealing force can be controlled in empty well and logging conditions, thereby improving the technical shortcomings of controlled pressure drilling, solving the problem of being unable to control the pressure after closing the well sealer during controlled pressure drilling construction, and also solving the problem that the derrick base is too low to install a full-sealing gate and annular blowout preventer. In addition, through the hydraulic control system, the hydraulic cylinder pressure is adjusted, and the sealing force of the rubber core on the wellhead and logging cable instruments can be adjusted, which can not only seal the wellhead and apply bottom hole back pressure, but also pull out the logging cable and instruments under pressure, thereby realizing full-process controlled pressure drilling.

[0036] The improved adjustment well sealing device and the wellhead sealing method for pressure controlled drilling empty and measuring conditions provided by the present invention will greatly assist the whole process of pressure controlled drilling and cost reduction and efficiency improvement. Through the sealing device and control method, the pressure control process under empty and measuring conditions can be realized, which makes up for the technical shortcomings, saves drilling costs, and lays the foundation for the technical solution of the pressure controlled drilling promotion and application project.

[0037] The above implementation modes are only used to illustrate the present invention, but not to limit the present invention. Ordinary technicians in the relevant technical field can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention. The patent protection scope of the present invention should be defined by the claims.

Claims

1. A perfect adjustment well sealing device, characterized in that: include: A sealer (1) and a rotary blowout preventer (2), wherein the lower end of the sealer (1) is connected to the rotary blowout preventer (2), the sealer (1) and the rotary blowout preventer (2) are sealed by a rotary blowout preventer seal (4), and a rotary blowout preventer clamp fluid cylinder (3) is installed on the side of the upper end of the rotary blowout preventer (2); the sealer (1) comprises a shell (6), the inner side of the upper part of the shell (6) is a rubber core (7), the inner side of the rubber core (7) is a sealer inner cavity (12), the lower part of the rubber core (7) is connected to a fluid cylinder mechanism, and the shell (6) and the sealer inner cavity (12) are sealed by a shell seal (11).

2. The perfect adjustment well sealing device according to claim 1, characterized in that: The liquid cylinder mechanism comprises a liquid cylinder opening (8), a liquid cylinder body (9), a liquid cylinder closing (10), a cylinder sleeve (14) and a liquid cylinder inner cavity (15); the inner side of the liquid cylinder opening (8) is connected to the liquid cylinder inner cavity (15); the outer side of the liquid cylinder inner cavity (15) is the liquid cylinder body (9); the outer side of the liquid cylinder body (9) is sleeved with the cylinder sleeve (14); and the bottom of the liquid cylinder body (9) is connected to the liquid cylinder closing (10).

3. The perfect adjustment well sealing device according to claim 2, characterized in that: The liquid cylinder opening (8) is horizontally installed inside the sealer (2), and the outer side of the liquid cylinder opening (8) is connected to the housing (6).

4. The perfect adjustment well sealing device according to claim 2, characterized in that: The liquid cylinder switch (10) is horizontally installed inside the sealer (2), and the outer side of the liquid cylinder switch (10) is connected to the housing (6).

5. The perfect adjustment well sealing device according to claim 1, characterized in that: The shell (6) is a rubber core shell, and the shell (6) comprises four parts, namely a truncated cone structure, a first cylinder, a second cylinder and a third cylinder, the truncated cone structure is connected to the first cylinder, the first cylinder is connected to the second cylinder, and the second cylinder is connected to the third cylinder.

6. The perfect adjustment well sealing device according to claim 5, characterized in that: The truncated cone structure includes a first circular bottom surface and a second circular bottom surface, the diameter of the first circular bottom surface is smaller than the diameter of the second circular bottom surface, the diameter of the second circular bottom surface is smaller than the bottom diameter of the first cylinder, the bottom diameter of the first cylinder is smaller than the bottom diameter of the second cylinder, the bottom diameter of the second cylinder is larger than the bottom diameter of the third cylinder, and the bottom diameter of the first cylinder is equal to the bottom diameter of the third cylinder.

7. The perfect adjustment well sealing device according to claim 5, characterized in that: The rubber core (7) is a spherical rubber core, the internal curvature of the truncated cone structure can match the spherical rubber core, and a plurality of eyebolts (5) are installed on the top of the truncated cone structure, and the spacing between the plurality of eyebolts (5) is equal.

8. The perfect adjustment well sealing device according to claim 5, characterized in that: The truncated cone structure and the first cylinder are connected via a plurality of housing cylinder head nuts (13), and the distances between the plurality of housing cylinder head nuts (13) are equal.

9. A wellhead sealing method for controlled pressure drilling empty well conditions according to any one of claims 1 to 8, characterized in that: include: Step S1: determine the target adjustment well, connect the sealing device, and fix the sealer with a clamp; Step S2: Observe whether the adjustment well has downhole fluid invasion. If not, apply a safe wellhead back pressure to the adjustment well according to the formation fracture pressure test data to suppress the invasion of downhole fluid; Step S3: Based on the observations in step S2, if the adjustment well is intruded by underground fluid, the hydraulic cylinder mechanism is closed by the hydraulic pump station, and the hydraulic oil enters the inner cavity of the hydraulic cylinder through the channel of the hydraulic cylinder closure, pushing the cylinder body to move upward, and through the action of the cylinder body and the shell, the rubber core is squeezed and deformed until the wellhead is sealed, and the pressure is controlled by the hydraulic pump station according to the actual situation underground; Step S4: After completing step S3, adjust the pressure-controlled back pressure pump or the well team variable frequency pump to apply back pressure to the bottom of the well by rotating the side outlet of the blowout preventer.

10. A wellhead sealing method for pressure controlled drilling and logging conditions according to any one of claims 1 to 8, characterized in that: include: Step S1: determine the target adjustment well, connect the sealing device, and fix the sealer with a clamp; Step S2: Observe whether the adjustment well has downhole fluid intrusion. If downhole fluid intrusion occurs, the hydraulic cylinder mechanism is closed by the hydraulic pump station, and the hydraulic oil enters the inner cavity of the hydraulic cylinder through the channel of the hydraulic cylinder closure, pushing the cylinder body to move upward. Through the action of the cylinder body and the shell, the rubber core is squeezed and deformed until the logging cable is sealed, thereby achieving the sealing of the wellhead logging cable and the instrument; Step S3: After completing step S2, the pressure of the hydraulic cylinder closing pressure is adjusted to cope with different bottom hole pressure conditions, and then the logging instrument is pulled out of the wellhead under pressure to achieve safe operation.

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