A pressure drilling device and method

Abstract

The present invention discloses a pressure drilling device and method, including a blowout preventer flange. A center drill pipe is inserted through the center of the blowout preventer flange. The bottom of the center drill pipe is connected to a drill bit through a centralizer sleeve. The top of the center drill pipe is connected to a drill pipe extension rod. An upper part of the blowout preventer flange is connected to a lower centralizer cross beam. The center drill pipe is inserted through the middle of the lower centralizer cross beam, and columns are inserted through both ends. The bottoms of the columns are fixed on a fixed seat of a valve to be drilled. A non-release cross beam is connected to the center drill pipe. The tops of the columns are connected to column extension rods. The top of the column extension rod is connected to a motor cross beam. Hydraulic cylinders are fixed at both ends of the motor cross beam, and a motor support is connected to the middle. A hydraulic motor is arranged on the motor support. A connecting spline and a drill pipe conversion shaft are arranged at the center of the motor support. The output shaft of the hydraulic motor is connected to the drill pipe conversion shaft through the connecting spline. The bottom of the drill pipe conversion shaft is connected to the top of the drill pipe extension rod. Both the hydraulic cylinder and the hydraulic motor are controlled by a hydraulic control console.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas exploitation, and particularly relates to a pressure drilling device and method, which are mainly applied to the maintenance of master valves of gas production trees, gathering pipelines, etc. Background Art

[0002] With the continuous exploitation time of oil and gas fields, due to various reasons, the valves at the gas production wellheads are severely corroded, the valve stems are broken, and the opening and closing are out of control. For example, the master valve cannot be opened or closed, and the lead screw of the master valve is broken, resulting in the inability to operate the master valve, seriously affecting the normal production of the wellhead, posing certain safety hazards, and greatly reducing the safety of subsequent wellhead operations.

[0003] At present, the conventional method for the master valves with the above-mentioned faults in China is to conduct a kill well operation to replace the new master valve or freeze to replace the faulty master valve. For some special wellhead master valves that cannot be opened or closed at all, the existing technology cannot solve the problems due to the lack of an operation channel. Repairing the faulty master valve by conducting a kill well operation is likely to affect the production of the wellhead under operation, and there are many subsequent remaining problems. The stroke of the existing drilling devices in the market is relatively small, which is likely to restrict the scope of drilling operations. The existing technology is relatively complex, requires a large amount of manpower and material resources for cooperation in operations, has a long cycle, and is costly. Summary of the Invention

[0004] The purpose of the present invention is to provide a pressure drilling device and method to overcome the defects of the existing technology. The present invention can establish a new operation channel, is simple to operate, has high efficiency, does not affect the normal production of the wellhead, has a relatively large drilling stroke, can meet the drilling requirements under complex well conditions, and the equipment drive part is hydraulically controlled. Through the combination of software and hardware, the device is made more intelligent and has high operation accuracy.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] A pressure drilling device includes a blowout preventer flange fixed on a spare control valve of a valve to be operated. A center drill pipe is inserted through the center of the blowout preventer flange, and V-shaped seals for sealing the center drill pipe are arranged on both the upper and lower sides of the blowout preventer flange. The bottom of the center drill pipe is connected to a drill bit through a centralizer sleeve, and the top of the center drill pipe is connected to a drill pipe extension rod;

[0007] The upper part of the blowout preventer flange is connected to a lower centralizing cross beam. The center drill pipe is inserted through the middle of the lower centralizing cross beam, and columns are inserted through both ends. The bottoms of the columns are fixed on a fixed seat of the valve to be drilled. A non-losing hand cross beam is connected to the center drill pipe. The non-losing hand cross beam is located above the lower centralizing cross beam, and the center drill pipe is inserted through the middle of the non-losing hand cross beam, and columns are inserted through both ends. The tops of the columns are connected to column extension rods;

[0008] The top of the column extension rod is connected to a motor beam, hydraulic cylinders are fixed at both ends of the motor beam, a motor bracket is connected in the middle, a hydraulic motor is arranged on the motor bracket, a connecting spline and a drill rod conversion shaft are arranged in the center of the motor bracket, the output shaft of the hydraulic motor is connected to the drill rod conversion shaft through the connecting spline, the lower part of the drill rod conversion shaft is inserted in the center of the motor beam, and the bottom of the drill rod conversion shaft is connected to the top of the drill rod extension rod;

[0009] The hydraulic cylinder and the hydraulic motor are both controlled by a hydraulic control console.

[0010] Furthermore, two upper and lower sealing grooves for installing V-shaped seals are arranged in the center of the blowout proof flange. The upper sealing groove is provided with a V-shaped sealing ring assembly, a V-shaped clamping nut and a sealing packing from bottom to top, and the lower sealing groove is provided with a V-shaped sealing ring assembly, a V-shaped clamping nut and a sealing packing from top to bottom.

[0011] Furthermore, the blowout-proof flange is fixed to the spare control valve of the valve to be operated by 8 stud bolts and matching nuts, the connecting surface is sealed by an octagonal gasket, and the blowout-proof flange is equipped with a sensor for measuring medium pressure or temperature parameters and an air release valve for discharging medium during the operation process.

[0012] Furthermore, the lower righting beam is composed of two male and female beams, which are connected by stud bolts. There are three through holes on the lower righting beam. The size of the middle through hole matches the size of the center drill rod and is used to pass the center drill rod. The through holes at the left and right ends are used to install left and right columns. The lower righting beam is used to right the blowout preventer flange and prevent the blowout preventer flange from rotating.

[0013] Furthermore, the lower righting beam and the holding beam are connected to the column through the column limit nut; a bearing is installed between the motor beam and the drill pipe conversion shaft, the motor bracket is threadedly connected to the motor beam, and the motor bracket is connected to the hydraulic motor by bolts.

[0014] Furthermore, a cooling water injection port connected to the drill rod extension rod and the center of the central drill rod is provided on the motor cross beam.

[0015] Furthermore, the drill rod extension rod is threadedly connected to the drill rod conversion shaft, the center drill rod and the drill rod extension rod are threadedly connected, the centering sleeve and the center drill rod are threadedly connected, and the drill bit and the centering sleeve are threadedly connected.

[0016] Furthermore, a plurality of positioning grooves are provided on the central drill rod and the drill rod extension rod, one of the positioning grooves is used to install a hand-holding crossbeam, and drill rod guard rings are installed on the remaining positioning grooves.

[0017] Furthermore, a hydraulic cylinder crossbeam is connected to the top of the hydraulic cylinder.

[0018] A pressure drilling method comprises the following steps:

[0019] Step 1: Perform a pressure test according to the test process requirements to ensure that the device is stable at rated pressure for more than 15 minutes without leakage;

[0020] Step 2: Operate the hydraulic control console to control the hydraulic cylinder to drive the center drill rod to move downward. When it moves to the lower limit position of the hydraulic cylinder, install the hand-holding crossbeam to fix the center drill rod through the hand-holding crossbeam, then loosen the connection between the center drill rod and the drill rod conversion shaft, operate the hydraulic control console to push up the hydraulic cylinder so that the hydraulic cylinder is at the upper limit position, and add a drill rod extension rod to the upper end of the center drill rod. Repeat this process so that the drill bit of the center drill rod can reach the position where it needs to work;

[0021] Step 3: Operate the hydraulic console to control the hydraulic cylinder to move downward, and at the same time operate the hydraulic console to control the hydraulic motor to rotate at a low speed. After the drill bit of the center drill rod reaches the specified position, continue to feed the drill, turn on the cooling water, operate the hydraulic console to control the hydraulic motor to drive the center drill rod to rotate axially, observe the control pressure on the hydraulic console, continue to operate the hydraulic console to control the axial pressure of the hydraulic cylinder to drive the drill bit to feed, observe the control pressure on the hydraulic console, constantly check the discharge of iron chips during the drilling process, repeat the above drilling action, replace the drill bit from small to large in turn, and finally replace the drill bit as required to complete the final hole expansion;

[0022] Step 4: Take out the center drill rod and drill bit, close the standby control valve, remove the drilling device and accessories, and clean the work area.

[0023] Compared with the prior art, the present invention has the following beneficial technical effects:

[0024] The present invention adopts a blowout-proof flange in combination with a V-shaped seal to conveniently and reliably seal the center drill rod. The present invention adopts a non-lost crossbeam to facilitate the disassembly and assembly of the center drill rod under pressure during the drilling process, making the operation process simple and safe. The present invention adopts a double hydraulic cylinder structure to simultaneously control the up and down movement of the center drill rod, making the operation process more stable and reliable. The double hydraulic cylinder structure is conducive to lengthening the center drill rod, so that the length of the center drill rod can be increased to a relatively long size. The present invention adopts a drill rod straightening sleeve to straighten the drill rod during the drilling process to reduce the friction resistance during the drilling process. The drill rod and the drill rod extension rod used in the present invention have limit grooves, which are convenient for controlling the center drill rod during the drilling process, connecting the drill rod or disassembling the drill rod. The drilling construction period is short, the impact on production capacity is small, and it is safer, more reliable, faster and more economical.

[0025] Furthermore, the present invention uses a sealing packing to facilitate replacement of the V-shaped sealing ring assembly.

[0026] Furthermore, the center hole of the center drill rod and the drill rod extension rod can cool the drill bit and lubricate it during the drilling process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a schematic diagram of the structure of the device of the present invention;

[0028] Figure 2 This is a simplified diagram of the drilling process of the present invention, where (a) is the installation of the tool, (b) is the lowering of the drill pipe, the cross beam fixes the drill pipe, (c) is the connection of the drill pipe, and (d) is the repeated lowering of the drill pipe;

[0029] Figure 3 This is a detailed diagram of the drilling process of the present invention, where (a) is the installation of the tool, (b) is the lowering of the drill pipe, (c) is the cross beam fixing the drill pipe, (d) is the lifting hydraulic cylinder, (e) is the connection of the drill pipe, (f) is the removal of the fixed cross beam, (g) is the lowering of the drill pipe, and (h) is the lifting of the drill pipe.

[0030] Among them, 1. Column fixing nut; 2. Column; 3. Drill bit; 4. Centralizer sleeve; 5. Reducing joint; 6. Central drill pipe; 7. V-shaped compression nut; 8. V-shaped sealing ring assembly; 9. Packing; 10. Column extension rod; 11. Non-losing cross beam; 12. Drill pipe extension rod; 13. Motor cross beam; 14. Motor support; 15. Hydraulic motor; 16. Hydraulic cylinder; 17. Connecting spline; 18. Drill pipe conversion shaft; 19. Bearing; 20. Drill pipe protection ring; 21. Column limit nut; 22. Lower centralizing cross beam; 23. Blowout preventer flange; 24. Hydraulic cylinder cross beam; 25. Cooling water injection port. Specific embodiments

[0031] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments:

[0032] See Figure 1A pressure drilling device includes a blowout prevention flange assembly, a non-lost crossbeam 11, a hydraulic motor part, a central drill rod part, and left and right column parts. The blowout prevention flange part is provided with a blowout prevention flange 23, which is fixed to the spare control valve of the valve to be operated by 8 stud bolts and nuts, and the connection surface is sealed by an octagonal gasket. The lower part of the spare control valve is connected to the valve to be drilled by a reducer 5. There is a channel on the blowout prevention flange 23 for installing sensors and air release valves. The sensor is mainly used to measure the pressure or temperature parameters of the medium, and the air release valve is mainly used for medium discharge during the operation process. The center of the blowout prevention flange 23 is provided with upper and lower sealing grooves for installing V-shaped seals. The sealing groove has internal threads and positioning platforms for fixing the sealing packing 9. The sealing packing 9 is used to press the V-shaped sealing ring assembly 8 to seal the central drill rod 6. The upper end of the blowout prevention flange 23 is provided with a lower straightening crossbeam 22 and a column limit nut 21, and the lower straightening crossbeam 22 is connected to the blowout prevention flange 23 by threads. The lower righting beam 22 is composed of two male and female beams, which are connected by stud bolts. There are three through holes on the lower righting beam 22. The size of the middle through hole matches the size of the center drill rod and is used to pass the center drill rod. The through holes at the left and right ends are used to install the left and right columns 2. The lower righting beam 22 is used to right the blowout preventer flange 23 and prevent the blowout preventer flange 23 from rotating.

[0033] The non-losing beam 11 includes a column limit nut, a stud column bolt, and a nut. The non-losing beam is connected and fixed by the stud column bolt and the nut. A limit hole is set in the middle to fix the center drill rod and the non-losing beam together. The column limit nut 21 is installed at the upper and lower ends of the non-losing beam 11, and the non-losing beam can be adjusted and fixed up and down. The column limit nut 21 is connected to the column 2 through a T-shaped thread.

[0034] The hydraulic motor assembly includes a hydraulic motor 15, a motor crossbeam 13, a motor bracket 14, a drill pipe conversion shaft 18 and a connecting spline 17. The motor crossbeam 13 is provided with a cooling water injection port 25 (there is an annular gap between the motor crossbeam 13 and the drill pipe conversion shaft 18, and the annular gap is connected to the hollow of the drill pipe extension rod and the center drill pipe). The motor bracket 14 is provided on the motor crossbeam 13 for fixing the hydraulic motor 15. A bearing 19 is installed between the motor crossbeam 13 and the drill pipe conversion shaft 18. The motor bracket 14 is threadedly connected to the motor crossbeam 13, and the motor bracket 14 is connected to the hydraulic motor 15 by bolts. The drill pipe conversion shaft 18 and the connecting spline 17 are provided in the center of the motor bracket 14 for connecting the hydraulic motor transmission shaft and the center drill pipe. The center drill pipe is connected to the drill pipe conversion shaft by threads, and the connecting spline 17 connects the hydraulic motor transmission shaft and the drill pipe conversion shaft 18.

[0035] The central drill pipe assembly includes a central drill pipe 6, a drill pipe extension rod 12, a drill bit 3, a centralizer sleeve 4, and a drill pipe protective ring 20. The drill pipe extension rod 12 is threadedly connected to the drill pipe conversion shaft 18. The central drill pipe 6 is threadedly connected to the drill pipe extension rod 12. The centralizer sleeve 4 is threadedly connected to the central drill pipe 6. The drill bit 3 is threadedly connected to the centralizer sleeve 4. Positioning grooves are provided on the central drill pipe 6 and the drill pipe extension rod 12 for connecting the non-release cross beam 11, and the drill pipe protective ring 20 is installed on the remaining positioning grooves. All the above components have holes in the center.

[0036] The left and right column assemblies include column fixing nuts 1, columns 2, column extension rods 10, hydraulic cylinders 16, and hydraulic cylinder cross beams 24. The column fixing nuts 1 are installed on the valves to be drilled. The columns 2 are threadedly installed on the column fixing nuts 1. T-shaped threads are provided on the columns 2. The column extension rods 10 are threadedly installed on the columns 2. The hydraulic cylinders 16 are bolted to the column extension rods 10. The hydraulic cylinder cross beam 24 consists of a male and a female cross beam, and the male and female cross beams are connected by double-headed bolts. There are 2 through holes on the hydraulic cylinder cross beam 24, and the through holes at the left and right ends are used to install and fix the left and right hydraulic cylinders 16.

[0037] The hydraulic control console includes an oil pump, an oil cylinder, a hydraulic motor, a manual pump, a solenoid valve, a display, etc. The hydraulic control system includes a manual control system and an electric control system.

[0038] See Figures 2-3 , a method for implementing a pressure drilling device, including the following steps:

[0039] 1) Device assembly: First, install the left and right column assemblies. Install the device column fixing nuts on the fixed seat of the valve to be drilled, and then install the column, column extension rod, hydraulic cylinder, and hydraulic cylinder cross beam in sequence. Then install the blowout preventer flange assembly, hydraulic motor assembly, central drill pipe assembly, and hydraulic control console, and conduct a trial run.

[0040] 2) Connect the drill pipe to the hydraulic cylinder cross beam, and adjust the drilling depth of the drill pipe to ensure the centricity of the drilling; tighten all the bolts, and open and close the valves that need to be opened and closed according to the regulations to complete the preparatory work before drilling;

[0041] 3) Device pressure test: The device is subjected to a pressure test according to the test process requirements to ensure that the device is stable under the rated pressure for 15 minutes without leakage.

[0042] 4) Process of connecting the central drill pipe: Generally, when connecting the central drill pipe, with the hydraulic cylinder at the upper limit position, operate the hydraulic control console to control the hydraulic cylinder to drive the central drill pipe downward. When it moves to the lower limit position of the hydraulic cylinder, install the non-release crossbeam, fix the central drill pipe through the non-release crossbeam, loosen the connection between the drill pipe and the drill pipe conversion shaft, operate the hydraulic control console to push the hydraulic cylinder upward so that the hydraulic cylinder is at the upper limit position, and then connect a drill pipe extension rod with the required length dimension at the upper end of the drill pipe to complete one process of connecting the central drill pipe. Repeat this process until the drill bit of the central drill pipe reaches the position where work is required. Conversely, the drill pipe extension rod can be disassembled. The next step is to carry out the drilling operation;

[0043] 5) Drilling process: A centralizer sleeve is installed on the central drill pipe. Operate the hydraulic control console to control the lower drill pipe of the hydraulic cylinder, and at the same time operate the hydraulic control console to control the hydraulic motor to rotate at a low speed. After the drill bit of the central drill pipe reaches the specified position, continue to feed the drill pipe downward, turn on the cooling water, operate the hydraulic control console, control the hydraulic motor, drive the central drill pipe to rotate axially, observe the control pressure on the hydraulic control console, continue to operate the hydraulic control console to control the hydraulic cylinder to apply axial pressure to drive the drill bit to feed, observe the control pressure on the hydraulic control console, and continuously check the discharge of iron filings from the filter during the drilling process. Repeat the above drilling actions, with the drill bits increasing in size from small to large, and replace the drill bits as required to complete the final reaming.

[0044] 6) Disassembly device: Lift out the central drill pipe and the drill bit, close the standby control valve, remove the drilling device and accessories, and clean the work site.

[0045] The following further describes the present invention in detail with specific embodiments:

[0046] Taking the drilling of the gate valve plate of the double-tubing Christmas tree No. 1 produced by Shanghai No. 2 Petroleum Machinery Factory as an example, the lead screw of the No. 1 main control valve at the wellhead is broken, and the flat gate valve cannot be opened. It is necessary to drill a hole under pressure to establish a new operation channel, and the wellhead oil pressure is 10 Mpa.

[0047] I. Construction preparation

[0048] 1. After the construction team arrives at the site, set up a safety warning area as required, and place the fire emergency equipment, safety warning signs, wind vanes, and escape route signs in place and fix them as required. Persons unrelated to the construction and on-site construction supervision and guardianship are not allowed to enter the safety warning area. The mobile phones of the staff are not allowed to enter the wellhead area. Arrange the drilling device neatly and check the tools and equipment.

[0049] 2. The on-site staff should wear PPE properly. When working at height, a safety belt needs to be equipped;

[0050] 3. Record the wellhead pressure.

[0051] 4. Conduct on-site measurements to determine the length of the drill pipe of the drilling tool and the depth position of the faulty valve plate, and make records.

[0052] 5. Provide construction safety education to construction workers.

[0053] 2. Operation process

[0054] 1. Preparation

[0055] Place the pressure drilling device and supporting equipment neatly, and check the tools and equipment. Take out the drilling device and supporting equipment, wipe them clean, connect the hydraulic control cabinet, place them neatly, and fill the hydraulic control console with oil; completely close the No. 4 gate valve and check for leakage, operate the gas wellhead according to the gas production process, remove the upper part of the No. 4 gate valve at the gas wellhead, and put it in the designated position.

[0056] 2. Drilling operation steps

[0057] 2.1 Remove the two pairs of bolts on the flange of the original wellhead big four-way, install the fixing seat on the big four-way, and then install a pair of columns on the fixing seat, install the 3 1 / 2'EUE conversion flange on the upper end of the Christmas tree, install the manual control valve on the conversion flange, connect the blowout preventer with the control valve, connect the column and the blowout preventer with the lower straightening beam, install the cylinder crossbeam and the cylinder upper crossbeam to fix the double hydraulic cylinders on the two columns respectively, and install the drill bit, straightening sleeve, drill pipe extension rod, drill pipe and other accessories, tighten the bolts at various places, and open and close the valves that need to be opened and closed according to regulations to complete the preparation work before drilling (the thickness of the drilling valve plate is 50mm).

[0058] 2.2 Connect the drill rod to the lower straightening beam and adjust the drill rod to ensure the centering of the drill hole;

[0059] 2.3 Drilling device pressure test:

[0060] The drilling device is subjected to a water pressure test as required to ensure that the wellhead pressure remains stable at 21MPa for 15 minutes without leakage.

[0061] 2.4 Open the hydraulic control console, check the panel display data, and check the hydraulic cylinder system and hydraulic motor system.

[0062] 2.5 After drilling begins, turn on the cooling system, use the first booster pump to drive the hydraulic motor for axial rotation, and the second booster pump to drive the hydraulic cylinder to control the feed. During the drilling process, constantly check the discharge of chips in the filter. This drilling uses a φ45mm drill bit with a depth of 45±1mm;

[0063] 2.6 After drilling to the designed depth, pull out the drill rod, replace the drill bit with a φ60mm one, and repeat step 2.5;

[0064] 2.7 Take out the drill rod and replace the positioning drill bit with a special drill bit for drilling;

[0065] 2.8 Apply axial pressure to drill through the ram, ensuring that the total stroke of the drilling tool is sufficient to drill through the ram;

[0066] 2.9 Remove the reaming bit, close the control valve, and remove the drilling tool to complete the drilling and reaming process.

[0067] 3. Restore the well site

[0068] Clean the work site, handle special items in accordance with relevant regulations, and prevent waste from polluting the environment. Keep a work record.

Claims

1. A pressure drilling device, characterized in that, It includes a blowout - proof flange (23) fixed on the standby control valve of the valve to be operated. A central drill pipe (6) is inserted through the center of the blowout - proof flange (23). V - type seals for sealing the central drill pipe (6) are provided on both the upper and lower sides of the blowout - proof flange (23). The bottom of the central drill pipe (6) is connected to the drill bit (3) through a centralizer sleeve (4), and the top of the central drill pipe (6) is connected to a drill pipe extension rod (12). The upper part of the blowout - proof flange (23) is connected to a lower centralizer cross - beam (22). The central drill pipe (6) is inserted through the middle of the lower centralizer cross - beam (22), and columns (2) are inserted through both ends. The bottom of the columns (2) is fixed on the fixed seat of the valve to be drilled. A non - releasing cross - beam (11) is connected to the central drill pipe (6). The non - releasing cross - beam (11) is located above the lower centralizer cross - beam (22). The central drill pipe (6) is inserted through the middle of the non - releasing cross - beam (11), and columns (2) are inserted through both ends. The top of the columns (2) is connected to a column extension rod (10). The top of the column extension rod (10) is connected to a motor cross - beam (13). Hydraulic cylinders (16) are fixed at both ends of the motor cross - beam (13), and a motor support (14) is connected in the middle. A hydraulic motor (15) is provided on the motor support (14). A connecting spline (17) and a drill pipe conversion shaft (18) are provided at the center of the motor support (14). The output shaft of the hydraulic motor (15) is connected to the drill pipe conversion shaft (18) through the connecting spline (17). The lower part of the drill pipe conversion shaft (18) is inserted through the center of the motor cross - beam (13), and the bottom of the drill pipe conversion shaft (18) is connected to the top of the drill pipe extension rod (12). Both the hydraulic cylinders (16) and the hydraulic motor (15) are controlled by a hydraulic control console. Two upper and lower sealing grooves for installing V - type seals are provided at the center of the blowout - proof flange (23). In the upper - side sealing groove, a V - type seal ring assembly (8), a V - type compression nut (7), and a sealing packing (9) are arranged from bottom to top in sequence. In the lower - side sealing groove, a V - type seal ring assembly (8), a V - type compression nut (7), and a sealing packing (9) are arranged from top to bottom in sequence. The lower centralizer cross - beam (22) is composed of a male and a female cross - beam. The male and female cross - beams are connected by stud bolts. There are 3 through - holes on the lower centralizer cross - beam (22). The size of the middle through - hole matches the size of the central drill pipe (6) for passing through the central drill pipe (6). The through - holes at the left and right ends are used for installing the left and right columns (2). The lower centralizer cross - beam (22) is used to centralize the blowout - proof flange (23) and prevent the blowout - proof flange (23) from rotating.

2. The pressure drilling device according to claim 1, characterized in that, The blowout - proof flange (23) is fixed on the standby control valve of the valve to be operated through 8 stud bolts and matching nuts. The connection surface is sealed by an octagonal gasket. Sensors for measuring medium pressure or temperature parameters and a gas - release valve for medium discharge during operation are installed on the blowout - proof flange (23).

3. The pressure drilling device according to claim 1, characterized in that, The lower straightening beam (22) and the holding beam (11) are both connected to the column (2) via a column limit nut (21); a bearing (19) is installed between the motor beam (13) and the drill pipe conversion shaft (18); the motor bracket (14) and the motor beam (13) are threadedly connected; and the motor bracket (14) and the hydraulic motor (15) are connected via bolts.

4. The pressure drilling device according to claim 1, characterized in that, The motor cross beam (13) is provided with a cooling water injection port (25) which is connected to the center of the drill rod extension rod (12) and the center drill rod (6).

5. The pressure drilling device according to claim 1, characterized in that, The drill rod extension rod (12) is connected to the drill rod conversion shaft (18) through a thread, the center drill rod (6) and the drill rod extension rod (12) are connected through a thread, the centering sleeve (4) and the center drill rod (6) are connected through a thread, and the drill bit (3) and the centering sleeve (4) are connected through a thread.

6. The pressure drilling device according to claim 1, characterized in that, The central drill rod (6) and the drill rod extension rod (12) are both provided with a plurality of positioning grooves, one of which is used for installing a hand-holding cross beam (11), and the remaining positioning grooves are provided with drill rod guard rings (20).

7. The pressure drilling device according to claim 1, characterized in that, The top of the hydraulic cylinder (16) is connected to a hydraulic cylinder crossbeam (24).

8. A pressure drilling method, which uses a pressure drilling device as described in claim 1, is characterized in that, The following steps are involved: Step 1: Perform a pressure test according to the test process requirements to ensure that the device is stable at rated pressure for more than 15 minutes without leakage; Step 2: operate the hydraulic control console to control the hydraulic cylinder (16) to drive the center drill rod (6) to move downward. When the hydraulic cylinder (16) moves to the lower limit position, install the non-loosening cross beam (11), fix the center drill rod (6) through the non-loosening cross beam (11), then loosen the connection between the center drill rod (6) and the drill rod conversion shaft (18), operate the hydraulic control console to push the hydraulic cylinder (16) upward so that the hydraulic cylinder (16) is at the upper limit position, and connect the drill rod extension rod (12) to the upper end of the center drill rod (6). Repeat this process so that the drill bit (3) of the center drill rod (6) can reach the position where work is required; Step 3: operate the hydraulic control console to control the hydraulic cylinder (16) to move downward, and at the same time operate the hydraulic control console to control the hydraulic motor (15) to rotate at a low speed. After the drill bit (3) of the center drill rod (6) is lowered to the specified position, continue to feed the drill, turn on the cooling water, operate the hydraulic control console to control the hydraulic motor (15) to drive the center drill rod (6) to rotate axially, observe the control pressure on the hydraulic control console, continue to operate the hydraulic control console to control the hydraulic cylinder (16) to apply axial pressure to drive the drill bit to feed, observe the control pressure on the hydraulic control console, and continuously check the discharge of iron chips during the drilling process. Repeat the above drilling action, replace the drill bit (3) from small to large in sequence, and finally replace the drill bit as required to complete the final hole expansion; Step 4: Take out the center drill rod (6) and the drill bit (3), close the standby control valve, remove the drilling device and accessories, and clean the work area.

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