Method and system for prolonging service cycle of gas drilling rubber core

Abstract

The invention relates to the technical field of oil and gas well drilling and completion, in particular to a method and system for prolonging the service cycle of a gas drilling rubber core, and the method comprises the steps that after the rubber core of a rotary blowout preventer is installed, a drilling tool continues to be put into a well mouth to the well bottom; gas is injected into a hexagonal drill rod of the drilling tool, and the gas returns out of a drill bit of the drilling tool along the drilling tool, enters an annular space between the drilling tool and a borehole and moves upwards; detecting whether sealing of the rubber core fails, and if not, discharging gas along an overflow pipeline on one side of the rotary blowout preventer; if yes, the gas is not exhausted any more, colloidal liquid is injected from the four-way position of the wellhead and enters the annulus, the gap between the hexagonal drill rod of the wellhead and the rubber core of the rotary blowout preventer is filled with liquid flow in the circumferential direction under washing of the gas in the lower annulus till sealing is completed, and then the gas continues to be exhausted. Through the method and the system, the possibility of sealing failure of the shale oil horizontal wellhead rubber core is reduced; and the overall drilling speed is relatively high.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well drilling and completion technology, and in particular to a method and system for extending the service life of gas drilling rubber cores. Background Technology

[0002] Numerous examples demonstrate that during gas drilling and completion, because the annulus consists of gas and solid rock cuttings, the rubber core inside the rotary blowout preventer (BOP) at the wellhead is prone to abnormal sealing failure due to "dry grinding" or scraping by "burrs" on the drill pipe couplings. This results in ineffective and timely wellhead pressure sealing, necessitating frequent replacement of the rotary BOP rubber core during gas drilling, which reduces drilling speed and significantly increases drilling costs. For instance, wells ** and **N1 used 12 rubber cores per well, with a drilling speed of 2.6 m / hour, resulting in a significantly extended drilling cycle.

[0003] To address the issue of wellhead seal failure in drilling operations, a sealing core suitable for large-diameter annular blowout preventers (BOPs) was designed. Based on the principle of virtual work and the constitutive equations of the Blatz and Ko hyperelastic models, a finite element model of the spherical seal core was established. This model simulated the deformation-sealing process (initial deformation, large deformation stage, and sealing contact) of the seal core under piston thrust, and its sealing performance under different shear moduli and piston strokes was studied. The seal core was also experimentally verified according to the technical requirements of national standards GB / T20174, 2009, and API16A. The results show that the sealing performance of the spherical seal core is significantly affected by the shear modulus of the material. As the shear modulus increases, the contact pressure first increases and then decreases, while the deformation decreases with increasing shear modulus. Regarding the BOP structural parameters, the larger the piston thrust, the greater the contact pressure and deformation of the seal core. No leakage occurred at the sealing site during the tests, proving that the developed seal core meets the sealing requirements.

[0004] Secondly, based on erosion tests of rubber specimens, the erosion model parameters for nitrile rubber were determined through inversion analysis using the LM optimization algorithm. The determined erosion model was then embedded into Fluent software via a UDF (User Descriptor Function) to calculate the erosion performance of the sealing core during well construction, considering the numerical model of the flow field near the semi-sealing gate of the blowout preventer. The variation of the amount of material removed from the sealing core with the well shut-in time was studied. The results yielded improved Finnie erosion model parameters for nitrile rubber. The maximum relative error between the erosion rate predicted by this model and the experimental data was only 5.77%, making it suitable for simulating the erosion performance of nitrile rubber components. During blowout preventer valve closure, the erosion of the sealing core by the rock-carrying drilling fluid mainly occurred in the high-speed rock cuttings collision zone at the end face edge. The erosion rate of the sealing core was linearly positively correlated with the sand content of the drilling fluid and non-linearly positively correlated with the flow velocity of the drilling fluid. As the gate opening decreased, the erosion rate increased exponentially. When the gate opening is 104mm, 26mm, and 6mm, the material removal rate of the rubber core is 1.52mm.3 / s, 5.22mm 3 / s and 28.3mm 3 The value per second indicates that the erosion of the rubber core is most severe in the later stage of well shut-in, just before the gate is about to close. The amount of material removed from the rubber core during the entire shut-in process increases with the shut-in duration; the rubber core volume removal amounts corresponding to shut-in durations of 3 seconds and 8 seconds are 5.04 mm and 5.04 mm, respectively. 3 and 13.43mm 3 .

[0005] Thirdly, high-density oil-based drilling fluids in small-bore drilling exhibit phenomena such as high annular circulation pressure loss, high pumping pressure, and high ignition pressure, leading to frequent overflows and leaks in pressure-sensitive formations, severely impacting operational safety. Taking the TF2 well (149.2mm borehole in volcanic rock formation) as an example, this paper analyzes the engineering risks caused by sudden changes in bottom hole pressure under different operating conditions, considering the high internal friction of high-density oil-based drilling fluids and the small borehole and depth. A technical approach of variable density pressure-controlled drilling is proposed: adjusting the drilling fluid density and controlling a certain wellhead pressure according to changes in circulation pressure loss, pumping pressure, and ignition pressure under different operating conditions to achieve a bottom hole pressure slightly higher than the formation pressure throughout the entire operation, maintaining a state of no overflow or leakage or only slight leakage in the wellbore, thus ensuring well control safety throughout the entire operation. Existing technology provides principles and control conditions for determining drilling fluid density and adjusting additional wellhead pressure under four operating conditions: drilling circulation, pump shutdown, tripping, and running. In application, the formation pressure, leakage pressure, and density values ​​under different operating conditions of well TF2 were calculated. This well utilized variable density pressure controlled drilling technology, achieving a safe drilling footage of 239.83m in a 149.2mm wellbore.

[0006] Fourth, to reduce or prevent critical structural failures of the spherical blowout preventer (BOP), theoretical calculations were performed on parameters such as piston stroke and rubber core extrusion amount of the FH35-35 spherical BOP, based on the existing structure and working principle of the spherical BOP. Uniaxial tensile, compression, and planar tensile tests were conducted on the rubber core material, and three sets of test data were optimized to obtain an optimized constitutive model of the rubber core material. Simultaneously, a full-size three-dimensional model of the spherical BOP was established, and finite element analysis was performed on this model to analyze the stress and deformation patterns of the rubber core and support, identify the underlying causes of failure of the rubber core and support, and make structural improvements to the rubber core and support. The results show that by changing the downward-sloping chamfer structure of the rubber core and increasing the thickness of the upper plate of the support from 40mm to 50mm, the stress at a certain point on the upper part of the rubber core decreased by 23.9MPa compared to before the improvement, and the maximum stress on the back of the support decreased by approximately 46.8–187.5MPa compared to before the improvement. The improved rubber core and support effectively improved the strength of the BOP, and the rubber core performed well in field use.

[0007] Fifth, to improve the sealing performance of the rotary control head rubber core during pressurized tripping, a finite element control equation for the dynamic sealing process was obtained based on the principle of virtual work, and a Yeoh constitutive model for the rubber core deformation process was established through uniaxial compression tests. A three-dimensional finite element model of the rubber core was established using the ABAQUS experimental platform. By simulating the dynamic sealing process of the rubber core during tripping, the stress distribution law on the sealing surface was obtained. The influence of structural parameters such as the inner cone angle, outer cone angle, and inner diameter of the rubber core on the sealing performance was studied. The results show that the contact pressure on the main sealing surface of the rubber core is greater than that on other parts, with the highest contact pressure at the inflection point between the main sealing surface and the inner cone surface. The contact pressure on the inner cone surface increases with the increase of the inner cone angle, while the contact pressure on the sealing surface fluctuates with the increase of the outer cone angle. The contact pressure on the main sealing surface decreases with the increase of the inner diameter. The structural parameters were optimized through orthogonal experiments, and the optimal combination of structural parameters was obtained as an inner cone angle of 24°, an outer cone angle of 64°, and a rubber core inner diameter of 79mm. The optimized scheme reduced the peak contact pressure by 0.51MPa and the Mises stress amplitude by 57.5%. Field application results show that the optimized solution significantly increases fatigue life while meeting the sealing requirements of the rubber core, verifying the accuracy of finite element simulation analysis.

[0008] Currently, the average service life of underbalanced rubber cores for petroleum gases is approximately 200 hours. The aforementioned existing technologies all address the problem of wellhead rubber core seal failure, and most methods for extending the service life of rubber cores focus on aspects such as the design of the rotating assembly structure, the rubber core structure design, and the rubber core formulation. Summary of the Invention

[0009] To address the aforementioned technical problems, this invention, starting from field construction, proposes a method and system for extending the service life of gas drilling rubber cores. This method can extend the service life of the rubber cores, reduce the possibility of rubber core seal failure at shale oil horizontal wellheads, and ensure a high overall drilling speed.

[0010] This invention is achieved by adopting the following technical solution: A method for extending the service life of gas drilling cartridges includes the following steps: S1. After the rubber core of the rotary blowout preventer is installed, continue to run the drill string down to the bottom of the well. S2. Gas is injected into the hexagonal drill pipe of the drill string. The gas flows back out from the drill bit of the drill string, enters the annulus between the drill string and the wellbore, and moves upward. S3. Check if the rubber core has failed to seal. If not, the gas will be discharged through the overflow line on one side of the rotating blowout preventer. If so, the gas will no longer be discharged. Inject the rubber liquid from the four-way valve at the wellhead. The rubber liquid enters the annulus and, under the flushing of the gas in the lower annulus, the liquid flow circumferentially fills the gap between the hexagonal drill pipe at the wellhead and the rubber core of the rotating blowout preventer until the seal is complete, and then continue to discharge the gas.

[0011] The viscosity of the colloidal liquid is 500 cps to 650 cps, and the film-forming speed is 1 minute to 2 minutes.

[0012] The installation of the rubber core specifically refers to: lifting a hexagonal drill pipe from the wellhead so that the end of the hexagonal drill pipe passes through the rubber core of the rotating blowout preventer; slowly lowering the rubber core of the rotating blowout preventer into the wellhead until the rubber core is placed inside the rotating blowout preventer and fixed; and then fastening the hexagonal drill pipe at the wellhead.

[0013] When the seal failure of the rubber core is detected, the gas will no longer be discharged, and the gas will act as a power source to force the rubber liquid into the annulus.

[0014] The gas discharged through the overflow line is then burned and discharged.

[0015] As the gas moves upward, it carries with it rock-cutting motion.

[0016] A system for extending the service life of gas drilling rubber cores includes drilling equipment. The drilling equipment includes drill strings and, from top to bottom, a rotary blowout preventer (BOP), an annular BOP, a double gate valve, and a four-way valve. BOP lines and kill injection lines are connected to both sides of the four-way valve. The drill strings include a hexagonal drill pipe, drill string, screw rod, and drill bit connected in sequence. A rubber core is located inside the rotary BOP. The system also includes a gas injection device, a rubber liquid injection device, and an overflow line. The gas injection device is connected to the hexagonal drill pipe and is used to introduce gas into the annulus. The rubber liquid injection device is connected to the kill injection line and is used to inject rubber liquid into the annulus at the four-way valve when the rubber core seal fails. Under the flushing action of the gas in the lower annulus, the rubber liquid circumferentially fills the gap between the hexagonal drill pipe and the rubber core at the wellhead until a seal is achieved. The overflow line is located on one side of the rotary BOP and is used to discharge the injected gas.

[0017] The overflow line is equipped with a valve, and the overflow line located between the rotary blowout preventer and the valve is also connected to the gelatinous liquid injection device through a connecting pipe, which is also equipped with a control valve.

[0018] It also includes a combustion pit, with the other end of the overflow pipeline laid to the combustion pit.

[0019] The overflow pipeline is also equipped with a gas-liquid separator, and the gas outlet of the gas-liquid separator is connected to the combustion pit through a discharge pipe.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This method can compensate for the failure of the rubber core seal of the rotary blowout preventer at the wellhead during gas-controlled drilling, extending the service life of the rubber core and reducing the possibility of rubber core seal failure at the shale oil horizontal wellhead; ensuring a high overall drilling speed and improving the safety of wellhead operations.

[0021] 2. In this invention, the rubber core is not always fixed inside the rotating blowout preventer. The rubber core is only installed and fixed at specific times to avoid damage to the rubber core during normal operation.

[0022] 3. In this invention, when the seal failure of the rubber core is detected, the gas is no longer discharged. The gas acts as a power source to press the gel liquid into the annulus. This fully utilizes the high pressure and high speed characteristics of the gas to ensure that the gel liquid can fill the gap between the hexagonal drill pipe at the wellhead and the rubber core of the rotating blowout preventer more quickly and stably, replacing the original gas medium and forming a complete gel liquid medium, so that the sealing effect can still be achieved.

[0023] 4. The gas discharged through the overflow pipeline is discharged after combustion to prevent the overflow of natural gas and other contaminants in the gas.

[0024] 5. As the gas moves upward, it carries rock cutting motion and is discharged along with the gas, which helps to improve drilling quality and speed.

[0025] 6. The system of this invention is equipped with a gas injection device and a gel liquid injection device. The gas in the annulus moves upward, and the gel liquid is injected into the annulus from the four-way valve. Under the scouring of the high-speed gas in the lower annulus, the liquid flow circumferentially fills the gap between the hexagonal drill pipe at the wellhead and the rubber core of the rotating blowout preventer; replacing the original gas medium; forming a complete layer of gel liquid medium; solving the problem of rubber core sealing failure, enabling drilling work to continue, and improving the service life of the rubber core.

[0026] 7. In this invention, the use of valves and control valves facilitates better control of the use of gelatinous liquids. Attached Figure Description

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments, wherein: Figure 1 This is a schematic diagram of the system structure of the present invention; Marked in the image: 1. Standpipe; 2. First valve; 3. Connecting line; 4. Gas injection device; 5. Hexagonal drill pipe; 6. Rubber core; 7. Rotary blowout preventer; 8. Double gate valve; 9. Four-way valve; 10. Second valve; 11. Blowout preventer line; 12. Kill injection line; 13. Third valve; 14. Gel liquid injection device; 15. Technical casing; 16. Drill pipe; 17. Screw rod; 18. Drill bit; 19. Valve; 20. Overflow line; 21. Gas-liquid separator; 22. Discharge pipe; 24. Combustion pit; 25. Annular blowout preventer; 26. Control valve. Detailed Implementation

[0028] Example 1 As a basic embodiment of the present invention, the present invention includes a method for extending the service life of gas drilling rubber cores, comprising the following steps: S1. After the rubber core 6 of the rotary blowout preventer 7 is installed, the drill string continues to be lowered to the bottom of the well.

[0029] S2. Gas is injected into the hexagonal drill pipe 5 of the drill string. The gas flows back out from the drill bit 18 of the drill string, enters the annulus between the drill string and the wellbore, and moves upward.

[0030] S3. Check if the seal of the rubber core 6 has failed. If not, the gas is discharged through the overflow line 20 on one side of the rotary blowout preventer 7. If so, the gas is no longer discharged, and a gel-like liquid is injected from the four-way valve 9 at the wellhead. The gel-like liquid enters the annulus, and under the flushing of the gas in the lower annulus, the liquid flows circumferentially to fill the gap between the hexagonal drill pipe 5 at the wellhead and the rubber core 6 of the rotary blowout preventer 7 until the seal is complete, and then the gas is discharged again.

[0031] Example 2 In a preferred embodiment of the present invention, the present invention includes a method for extending the service life of gas drilling rubber cores, comprising the following steps: S1. After the rubber core 6 of the rotary blowout preventer 7 is installed, the drill string continues to be lowered to the bottom of the well.

[0032] S2. Gas is injected into the hexagonal drill pipe 5 of the drill string. The gas flows back out from the drill bit 18 of the drill string, enters the annulus between the drill string and the wellbore, and moves upward. The gas can be nitrogen.

[0033] S3. Check if the seal of the rubber core 6 has failed. If not, the gas is discharged through the overflow line 20 on one side of the rotary blowout preventer 7. If so, the gas is no longer discharged, and a gel-like liquid is injected from the four-way valve 9 at the wellhead through a separate power source. The gel-like liquid enters the annulus, and under the flushing of the gas in the lower annulus, the liquid flow circumferentially fills the gap between the hexagonal drill pipe 5 at the wellhead and the rubber core 6 of the rotary blowout preventer 7 until the seal is complete. Then, the injection of gel-like liquid is stopped, and the gas continues to be discharged.

[0034] S4. The exhaust gas is vented after combustion.

[0035] Example 3 In another preferred embodiment of the present invention, the present invention includes a system for extending the service life of gas drilling gel cores, comprising drilling equipment, a gas injection device 4, a gel liquid injection device 14, and an overflow line 20. The drilling equipment can employ conventional techniques in the art, and this embodiment does not modify it. Specifically, the drilling equipment includes drill strings and, from top to bottom, a rotary blowout preventer 7, an annular blowout preventer 25, a double gate valve 8, and a four-way valve 9. Blowout preventer lines 11 and kill injection lines 12 are respectively connected to both sides of the four-way valve 9. The drill strings include a hexagonal drill pipe 5, a drill rod 16, a screw rod 17, and a drill bit 18 connected in sequence.

[0036] The rotary blowout preventer 7 contains a rubber core 6 for mating with the hexagonal drill pipe 5 to achieve a seal. The gas injection device 4 is connected to the hexagonal drill pipe 5 and is used to introduce gas into the annulus. The gelatinous liquid injection device 14 is connected to the kill injection line 12 and is used to inject gelatinous liquid into the annulus at the four-way connector 9 when the seal of the rubber core 6 fails. Under the flushing effect of the gas in the lower annulus, the gelatinous liquid flows circumferentially to fill the gap between the hexagonal drill pipe 5 and the rubber core 6 at the wellhead until a seal is achieved. The overflow line 20 is located on one side of the rotary blowout preventer 7 and is used to discharge the injected gas.

[0037] Example 4 As the preferred embodiment of the present invention, the present invention includes a system for extending the service life of gas drilling rubber cores, comprising drilling equipment, a gas injection device 4, a rubber liquid injection device 14, an overflow line 20, and a combustion pit 24. The drilling equipment includes drill string and, from top to bottom, a rotary blowout preventer 7, an annular blowout preventer 25, a double gate valve 8, and a four-way valve 9. The drill string includes a hexagonal drill pipe 5, a drill pipe 16, a screw rod 17, and a drill bit 18 connected in sequence. The rotary blowout preventer 7 contains a rubber core 6 for cooperating with the hexagonal drill pipe 5 to achieve a seal. Blowout preventer lines 11 and kill injection lines 12 are respectively connected to both sides of the four-way valve 9.

[0038] The gas injection device 4 can be used to generate and inject nitrogen gas. The gas injection device 4 is connected to the hexagonal drill pipe 5 via the connecting pipeline 3 and the riser 1 located next to the derrick. A first valve 2 may be installed on the connecting pipeline 3.

[0039] The overflow line 20 is located on one side of the rotary blowout preventer 7. A gas-liquid separator 21 is also installed on the overflow line 20, and the outlet of the gas-liquid separator 21 is connected to the combustion pit 24 via a discharge pipe 22. Furthermore, a valve 19 is installed on the overflow line 20, positioned between the rotary blowout preventer 7 and the gas-liquid separator 21. The overflow line 20, located between the rotary blowout preventer 7 and the valve 19, is also connected to a gelatinous liquid injection device 14 via a connecting pipe, which is equipped with a control valve 26. The other end of the gelatinous liquid injection device 14 is used to connect to a well-kill injection line 12, which may be equipped with a third valve 13.

[0040] A method for extending the service life of gas drilling cartridges based on the above system includes the following steps: S1. After the rubber core 6 of the rotary blowout preventer 7 is installed, the drill string continues to be run down to the bottom of the well. Specifically, the technical casing 15 is run down to the designed well depth and cemented; the gas injection device 4 is connected to the riser 1 next to the derrick via the connecting line 3. The blowout preventer line 11 and the kill injection line 12 are connected to both sides of the wellhead four-way connector 9. The gel liquid injection device 14 is connected to the other end of the kill injection line 12. The double gate valve 8 is connected to the wellhead four-way connector 9. The annular blowout preventer 25 is connected to the double gate valve 8. The rotary blowout preventer 7 is connected to the annular blowout preventer 25. The drill string is run down to the wellhead. The drill string is run down to 500 meters. A hexagonal drill pipe 5 is lifted from the wellhead, and the end of the hexagonal drill pipe 5 passes through the rubber core 6 of the rotary blowout preventer 7. The rubber core 6 of the rotary blowout preventer 7 is slowly lowered down from the wellhead. The rubber core 6 is placed into the rotary blowout preventer 7 and secured. The hexagonal drill pipe 5 is then fastened at the wellhead. The drilling tools were continued to be lowered from the wellhead to the bottom of the well.

[0041] S2. Inject gas into the hexagonal drill pipe 5. The injected gas returns through the riser 1, hexagonal drill pipe 5, drill pipe 16, screw 17, and drill bit 18, entering the annulus between the drill string and the wellbore. From the annulus, the gas carries the broken rock cuttings upwards.

[0042] S3. Check if the seal of the rubber core 6 has failed. If not, open valve 19 on the overflow line 20 and close control valve 26 on the connecting pipe. The gas carrying the rock cuttings will be discharged through the overflow line 20 on one side of the rotating blowout preventer 7. After gas-liquid separation, the gas and rock cuttings enter the discharge pipe 22 and reach the combustion pit 24 for combustion before being vented. The gas reaching the combustion pit 24 contains injected nitrogen and natural gas combustion.

[0043] If the seal fails, close valve 19 on overflow line 20, open control valve 26 on connecting pipe, and open third valve 13 on kill injection line 12. Gas enters gelatinous liquid injection device 14 through connecting pipe, forcing gelatinous liquid in gelatinous liquid injection device 14 into kill injection line 12, and enters the annulus from the four-way connector 9 at the wellhead. Under the scouring of high-speed gas in the lower annulus, the liquid flow circumferentially fills the gap between the hexagonal drill pipe 5 at the wellhead and the rubber core 6 of the rotating blowout preventer 7. It replaces the original gas medium, forming a complete layer of gelatinous liquid medium, creating a good seal and ensuring the sealing effect of the wellhead.

[0044] The gelatinous liquid can be a high-viscosity adhesive. Specifically, the viscosity of the gelatinous liquid can be 500 cps to 650 cps, the flowability can be 1.8 to 2.1, the minimum film-forming temperature can be 10 degrees to 40 degrees, and the film-forming speed can be 1 minute to 2 minutes.

[0045] After sealing is completed, open valve 19 on overflow line 20, close control valve 26 on connecting pipe, and close third valve 13 on kill injection line 12. Downhole circulating medium (gas + rock cuttings + a small amount of liquid) passes through overflow line 20 on one side of rotating blowout preventer 7. After gas-liquid separation, the gas and rock cuttings enter discharge pipe 22 and reach combustion pit 24 for combustion before being vented. The gas reaching combustion pit 24 includes injected nitrogen and natural gas.

[0046] The above methods can achieve sealing under the gel-like liquid at the wellhead during gas drilling; improve the safety of gas drilling; extend the service life of the rubber core 6 of the rotary blowout preventer 7; and increase the speed of gas drilling.

[0047] In summary, any other corresponding modifications made by those skilled in the art after reading this invention document, without requiring creative mental effort, based on the technical solutions and concepts of this invention, are all within the scope of protection of this invention.

Claims

1. A method for extending the service life of gas drilling rubber cores, characterized in that: Includes the following steps: S1. After the rubber core (6) of the rotary blowout preventer (7) is installed, the drill string continues to be lowered to the bottom of the well. S2. Gas is injected into the hexagonal drill pipe (5) of the drill string. The gas flows back out from the drill bit (18) of the drill string, enters the annulus between the drill string and the wellbore, and moves upward. S3. Check if the rubber core (6) has failed to seal. If not, the gas is discharged through the overflow line (20) on one side of the rotary blowout preventer (7). If so, the gas is no longer discharged. The gel liquid is injected from the four-way valve (9) at the wellhead. The gel liquid enters the annulus. Under the flushing of the gas in the lower annulus, the liquid flow circumferentially fills the gap between the hexagonal drill pipe (5) at the wellhead and the rubber core (6) of the rotary blowout preventer (7) until the seal is completed. Then the gas is discharged.

2. The method for extending the service life of gas drilling rubber cores according to claim 1, characterized in that: The viscosity of the colloidal liquid is 500 cps to 650 cps, and the film-forming speed is 1 minute to 2 minutes.

3. The method for extending the service life of gas drilling rubber cores according to claim 2, characterized in that: The installation of the rubber core (6) specifically refers to: lifting a hexagonal drill pipe (5) of a drill string at the wellhead, so that the end of the hexagonal drill pipe (5) passes through the rubber core (6) of the rotary blowout preventer (7); lifting the rubber core (6) of the rotary blowout preventer (7) at the wellhead and slowly lowering it in until the rubber core (6) is placed inside the rotary blowout preventer (7) and the rubber core (6) is fixed; and fastening the hexagonal drill pipe (5) together at the wellhead.

4. The method for extending the service life of gas drilling rubber cores according to claim 2, characterized in that: When the seal failure of the rubber core (6) is detected, the gas will no longer be discharged, and the gas will act as a power source to force the rubber liquid into the annulus.

5. A method for extending the service life of gas drilling rubber cores according to claim 2, characterized in that: The gas discharged through the overflow line (20) is discharged after combustion.

6. A method for extending the service life of gas drilling rubber cores according to claim 2, characterized in that: As the gas moves upward, it carries with it rock-cutting motion.

7. A system for extending the service life of gas drilling rubber cores, comprising drilling equipment, the drilling equipment including drill string and, from top to bottom, a rotary blowout preventer (7), an annular blowout preventer (25), a double gate valve (8), and a four-way valve (9), wherein blowout preventer lines (11) and kill injection lines (12) are respectively connected to both sides of the four-way valve (9); the drill string includes a hexagonal drill pipe (5), a drill pipe (16), a screw (17), and a drill bit (18) connected in sequence; the rotary blowout preventer (7) contains a rubber core (6); characterized in that: It also includes a gas injection device (4), a gelatinous liquid injection device (14), and an overflow line (20); the gas injection device (4) is connected to the hexagonal drill pipe (5) and is used to introduce gas into the annulus; the gelatinous liquid injection device (14) is connected to the kill injection line (12) and is used to inject gelatinous liquid into the annulus at the four-way (9) when the seal of the rubber core (6) fails. Under the flushing of the gas in the lower annulus, the gelatinous liquid flows circumferentially to fill the gap between the hexagonal drill pipe (5) and the rubber core (6) at the wellhead until the seal is completed; the overflow line (20) is set on one side of the rotating blowout preventer (7) and is used to discharge the injected gas.

8. The system for extending the service life of gas drilling rubber cores according to claim 7, characterized in that: The overflow line (20) is equipped with a valve (19). The overflow line (20) located between the rotary blowout preventer (7) and the valve (19) is also connected to the gel liquid injection device (14) through a connecting pipe. The connecting pipe is also equipped with a control valve (26).

9. A system for extending the service life of gas drilling rubber cores according to claim 7, characterized in that: It also includes a combustion pit (24), with the other end of the overflow pipeline (20) laid to the combustion pit (24).

10. A system for extending the service life of gas drilling rubber cores according to claim 8, characterized in that: The overflow pipeline (20) is also equipped with a gas-liquid separator (21), and the outlet of the gas-liquid separator (21) is connected to the combustion pit (24) through the discharge pipe (22).

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