Oil and gas drilling coring tool and method

Abstract

The invention discloses an oil and gas drilling coring tool and method. The device comprises a barrel, a sealing ring, a shear pin, a mandrel, a power shaft, a spring, a sealing ball, a single-flow valve seat, a core claw and a core bit. During normal coring drilling, the drilling pressure and torque transmitted by the upper drill string are transmitted to the core bit through the barrel, and the core bit grinds the formation under the action of the drilling pressure and torque, and the formed core enters the hollow coring section of the core bit; when it is necessary to cut the core, a steel ball with a diameter larger than the inner diameter of the central flow channel of the mandrel is dropped into the drill string from the ground, the steel ball blocks the central flow channel of the mandrel and holds the pressure, the shear pin between the mandrel and the barrel is sheared off under the action of the drilling fluid pressure, the mandrel moving downward compresses the spring and pushes the power shaft and the core claw to move downward, the claw block on the core claw slides on the slope surface of the core bit and contracts inward, the slip teeth on the claw block clamp the core and then lift the drill string, so that the core can be pulled off.

Description

Technical Field

[0001] The invention relates to a downhole tool, in particular to an oil and gas drilling coring tool and method, belonging to the technical field of mechanical engineering or drilling engineering. Background Art

[0002] In oil and gas exploration, the properties of underground rock formations are the key to judging the quality of oil fields. Since the rock formations that store oil and gas are usually buried deep underground, it is difficult to directly detect the properties of underground rock formations using conventional detection methods. The usual method of exploring underground rock formations is to take rock formation samples from the formations through drilling coring tools. This type of rock formation sample is called a core, and then the core is analyzed and processed. Through the detection of the core, the sedimentary characteristics, lithological characteristics, oil, gas, water and other characteristics of the rock formation and the underground structure can be determined, and the underground structure and rock deposition environment can be studied intuitively, and the mineral storage conditions can be understood. Only through the analysis and research of the core can a reasonable and scientific oil and gas development plan be formulated to improve the efficiency of oil and gas extraction.

[0003] Drilling coring tools are important equipment widely used in formation surveys. They are tools for bringing underground rock formations to the surface. Coring tools are divided into conventional coring tools and special coring tools according to the coring method and purpose; they can be divided into single-barrel coring tools and double-barrel coring tools according to tool structure; they can be divided into self-locking, pressurized, differential, and sand-card coring tools according to the cutting force. Coring is mainly divided into two operating links. The first is the annular drill bit drilling down, and a cylindrical rock column is formed at the inner barrel; the second is when the core is formed to a certain length, the core is cut and taken out. In the conventional coring process, as the drill bit descends, the core enters the inner barrel. Due to the complexity of the underground rock formations, the core may bend or collapse in the inner barrel due to its long length and low structural strength, causing the core to come into contact with the inner barrel, resulting in blockage of the inner barrel. The core cannot continue to form normally. If the coring tool continues to drill after blockage occurs, it will cause irreversible damage to the coring tool. Therefore, there is an urgent need for a coring tool that can detect coring blockage during coring. Summary of the invention

[0004] The purpose of the present invention is to provide an oil and gas drilling coring tool and method for achieving safe and efficient coring and thus conducting formation evaluation.

[0005] The technical solution adopted by the present invention is:

[0006] A coring tool for oil and gas drilling comprises a barrel, a sealing ring, a shear pin, a mandrel, a power shaft, a spring, a sealing ball, a check valve seat, a core claw and a core drill bit, wherein the upper portion of the barrel is connected to a drill string, and the lower end of the barrel is connected to the core drill bit by a thread, the sealing ring is arranged between the outer wall of the mandrel and the inner wall of the barrel, one end of the shear pin is inserted into the mandrel and the other end is fixed to the barrel, a spring is arranged between the mandrel and the power shaft, the check valve seat is fixed to the inside of the power shaft by a thread, a sealing ball is arranged between the check valve seat and the power shaft, and the lower end of the power shaft is connected to the upper end of the core claw by a thread.

[0007] The barrel is provided with a shell female buckle, a pin threaded hole, a pressure-holding and drainage hole and a shell male buckle. The shell female buckle connects the barrel to the upper drill string. The number of the pin threaded holes is 2 and they are symmetrically distributed. The number of the pressure-holding and drainage holes is 2 and they are symmetrically distributed. The shell male buckle connects the barrel to the coring drill bit.

[0008] The spindle is provided with a sealing ring groove, a pin mounting ring groove, a spindle central flow channel, a spindle branch flow channel, a spindle plunger cavity and a spindle spring cavity. The drilling fluid flowing into the spindle central flow channel flows to the outside of the spindle through the spindle branch flow channel; one end of the shear pin is fixed in the pin threaded hole of the cylinder through a thread and the other end is inserted into the pin mounting ring groove; the sealing ring is arranged in the sealing ring groove.

[0009] The power shaft is provided with a power shaft plunger, power shaft side holes, a valve seat connecting buckle, a power shaft core cavity and a power shaft female buckle. The upper end of the power shaft plunger is inserted into the core shaft plunger cavity. The spring is sleeved on the outside of the power shaft plunger and placed in the core shaft plunger cavity. The single-flow valve seat is connected to the valve seat connecting buckle through threads, and the sealing ball is arranged in the central flow channel of the power shaft.

[0010] Furthermore, when the coring tool is working, the spring is in a pre-tightened state.

[0011] Furthermore, the axial force exerted by the cylinder on the spring through the shear pin and the axial force exerted by the drilling fluid on the upper end surface of the power shaft act together on the power shaft to overcome the friction resistance of the core column on the power shaft.

[0012] After the mandrel is installed inside the cylinder through the shear pins, the mandrel blocks the pressure-retaining drainage hole.

[0013] Furthermore, the drilling fluid pressure in the cylinder is higher than the drilling fluid pressure outside the cylinder. Since the pressure-holding and drainage holes are blocked, the drilling fluid in the cylinder cannot be connected to the outside of the cylinder.

[0014] The single-flow valve seat is provided with a valve seat hollow flow channel, a conical surface and a hexagonal surface. The valve seat hollow flow channel is used to discharge drilling fluid to the central flow channel of the power shaft when the core moves upward, the conical surface is used to set the sealing ball, and the hexagonal surface is used for the installation and removal of the single-flow valve seat.

[0015] Furthermore, during normal drilling, the sealing ball stays on the conical surface of the single-flow valve seat under the action of its own weight, thereby blocking the hollow flow channel of the valve seat and preventing the drilling fluid pressure from directly acting on the upper surface of the core.

[0016] The core claw is provided with a core claw male buckle, a claw block and a slip tooth. The core claw male buckle is connected to the cylinder body. The claw blocks are evenly distributed around the core claw. A longitudinal groove is provided between the claw blocks. The slip tooth is used for grasping the core.

[0017] Furthermore, due to the arrangement of the longitudinal grooves between the claw blocks, the lower ends of the claw blocks of the core claws can be contracted to grip the outer surface of the core column.

[0018] The coring drill bit is provided with a slope surface, a hollow coring section and a drill bit drainage channel. When the claw block slides along the slope surface, the slip teeth on the claw block will clamp the core. The inner diameter of the hollow coring section is the same as the outer diameter of the core taken.

[0019] The inner diameter of the core claw is the same as the inner diameter of the core cavity of the power shaft and is 1-3 mm smaller than the inner diameter of the core drill bit.

[0020] Furthermore, the diameter of the core taken is determined by the inner diameter of the core bit. In order to reduce the friction of the core column in the core claw and the core cavity of the power shaft, the outer diameter of the core column is slightly smaller than the inner diameter of the core claw and the core cavity of the power shaft.

[0021] During normal coring drilling, the drilling pressure and torque transmitted by the upper drill string are transmitted to the coring drill bit through the barrel. The drilling fluid flowing from the upper drill string to the barrel flows through the central flow channel of the mandrel, the branch flow channel of the mandrel, the annular flow channel between the outer wall of the mandrel and the inner wall of the barrel, and the drill bit drainage channel in turn. The coring drill bit grinds the formation under the action of drilling pressure and torque, and the formed core enters the hollow coring section of the coring drill bit. In this process, the drilling fluid in the core cavity of the power shaft passes through the hollow flow channel of the valve seat, and after pushing open the sealing ball, it flows to the central flow channel of the power shaft and the side discharge holes of the power shaft, and flows to the annulus formed by the outer wall of the power shaft and the inner wall of the barrel; when it is necessary to cut the core, a steel ball with a diameter larger than the inner diameter of the central flow channel of the mandrel is dropped into the drill string from the ground. The steel ball blocks the central flow channel of the mandrel and holds the pressure. Under the action of the drilling fluid pressure, the mandrel and The shear pins between the barrels are sheared off, and the downward moving mandrel compresses the spring and pushes the power shaft and the core claw to move downward. The claw block on the core claw slides on the slope surface of the coring drill bit and contracts inward. The slip teeth on the claw block clamp the core and then lift the drill string to break the core. During the core cutting process, when the shear pins are sheared off and the mandrel moves downward, the pressure-holding drainage holes that are blocked during normal drilling will be unblocked, so that the inside and outside of the barrel are connected to avoid abnormally high pressure. When drilling abnormalities occur, such as the core being stuck in the core claw or the power shaft, the core will push the core claw and the power shaft to overcome the pressure of the spring and move upward, further causing the power shaft plunger to slide in the mandrel plunger cavity and block the mandrel diversion channel, so that the ground pump pressure increases rapidly, thereby monitoring the drilling status.

[0022] Compared with the prior art, the present invention has the following beneficial effects: (1) when the core is stuck during coring drilling, the power shaft plunger of the power shaft blocks the mandrel branch channel, causing the drilling fluid to be pressurized, so that the downhole drilling situation can be determined by measuring the surface pressure; (2) the present invention does not include electronic components and has high reliability for complex underground conditions such as high temperature and high pressure; (3) the structure of the present invention is easy to install and disassemble. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a structural schematic diagram of an oil and gas drilling coring tool of the present invention;

[0024] Figure 2 This is a schematic structural diagram of an oil and gas drilling coring tool of the present invention during normal coring;

[0025] Figure 3 This is a schematic diagram of the structure of an oil and gas drilling coring tool of the present invention when a blockage occurs;

[0026] Figure 4 It is a structural schematic diagram of a barrel of an oil and gas drilling coring tool of the present invention;

[0027] Figure 5 Another structural schematic diagram of a barrel of an oil and gas drilling coring tool according to the present invention;

[0028] Figure 6 This is a schematic structural diagram of a mandrel of an oil and gas drilling coring tool according to the present invention;

[0029] Figure 7 Another structural schematic diagram of a mandrel of an oil and gas drilling coring tool of the present invention;

[0030] Figure 8 This is a schematic structural diagram of a power shaft of an oil and gas drilling coring tool according to the present invention;

[0031] Fig. 9 Another structural schematic diagram of a power shaft of an oil and gas drilling coring tool of the present invention;

[0032] Fig.10 It is a structural schematic diagram of a single-flow valve seat of an oil and gas drilling coring tool of the present invention;

[0033] Fig.11 It is a structural schematic diagram of a core claw of an oil and gas drilling coring tool of the present invention;

[0034] Fig.12 Another structural schematic diagram of a core claw of an oil and gas drilling coring tool according to the present invention;

[0035] Fig.13 It is a structural schematic diagram of a coring drill bit of an oil and gas drilling coring tool of the present invention;

[0036] In the figure: 1-cylinder, 1a-housing female buckle, 1b-pin threaded hole, 1c-pressure drain hole, 1d-housing male buckle, 2-sealing ring, 3-shear pin, 4-spindle, 4a-sealing ring groove, 4b-pin mounting ring groove, 4c-spindle center flow channel, 4d-spindle branch flow channel, 4e-spindle plunger cavity, 4f-spindle spring cavity, 5-power shaft, 5a-power shaft plunger, 5b-power shaft Side discharge hole, 5c-valve seat connecting buckle, 5d-power shaft core cavity, 5e-power shaft female buckle, 6-spring, 7-sealing ball, 8-single flow valve seat, 8a-valve seat hollow flow channel, 8b-conical surface, 8c-hexagonal, 9-core claw, 9a-core claw male buckle, 9b-claw block, 9c-Kava tooth, 10-coring drill bit, 10a-slope surface, 10b-hollow coring section, 10c-drill bit drainage channel. DETAILED DESCRIPTION

[0037] The present invention will be further described below in conjunction with the accompanying drawings.

[0038] Example:

[0039] like Figures 1 to 13As shown, an oil and gas drilling coring tool comprises a barrel 1, a sealing ring 2, a shear pin 3, a spindle 4, a power shaft 5, a spring 6, a sealing ball 7, a check valve seat 8, a core claw 9 and a core drill bit 10, characterized in that the upper part of the barrel 1 is connected to the drill string, the lower end of the barrel 1 is connected to the core drill bit 10 by a thread, the sealing ring 2 is arranged between the outer wall of the spindle 4 and the inner wall of the barrel 1, one end of the shear pin 3 is inserted into the spindle 4 and the other end is fixed on the barrel 1, a spring 6 is arranged between the spindle 4 and the power shaft 5, the check valve seat 8 is fixed inside the power shaft 5 by a thread, a sealing ball 7 is arranged between the check valve seat 8 and the power shaft 5, and the lower end of the power shaft 5 is connected to the upper end of the core claw 9 by a thread.

[0040] The barrel 1 is provided with a shell female buckle 1a, a pin threaded hole 1b, a pressure-holding and drainage hole 1c and a shell male buckle 1d. The shell female buckle 1a connects the barrel 1 to the upper drill string. The number of the pin threaded holes 1b is 2 and they are symmetrically distributed. The number of the pressure-holding and drainage holes 1c is 2 and they are symmetrically distributed. The shell male buckle 1d connects the barrel 1 to the coring drill bit 10.

[0041] The spindle 4 is provided with a sealing ring groove 4a, a pin mounting ring groove 4b, a spindle central flow channel 4c, a spindle branch flow channel 4d, a spindle plunger cavity 4e and a spindle spring cavity 4f. The drilling fluid flowing into the spindle central flow channel 4c flows to the outside of the spindle 4 through the spindle branch flow channel 4d; one end of the shear pin 3 is fixed to the pin threaded hole 1b of the cylinder 1 by a thread and the other end is inserted into the pin mounting ring groove 4b; the sealing ring 2 is arranged in the sealing ring groove 4a.

[0042] The power shaft 5 is provided with a power shaft plunger 5a, a power shaft side row hole 5b, a valve seat connecting buckle 5c, a power shaft core cavity 5d and a power shaft female buckle 5e. The upper end of the power shaft plunger 5a is inserted into the spindle plunger cavity 4e, the spring 6 is sleeved on the outside of the power shaft plunger 5a and the spring 6 is placed in the spindle plunger cavity 4e, the single-flow valve seat 8 is connected to the valve seat connecting buckle 5c by threads, and the sealing ball 7 is arranged in the central flow channel 5f of the power shaft.

[0043] Furthermore, when the coring tool is working, the spring 6 is in a pre-tightened state.

[0044] Furthermore, the axial force exerted by the cylinder on the spring 6 through the shear pin 3 and the axial force exerted by the drilling fluid on the upper end surface of the power shaft 5 act together on the power shaft 5 to overcome the friction resistance of the core column on the power shaft.

[0045] After the mandrel 4 is installed inside the cylinder 1 through the shear pin 3, the mandrel 4 blocks the pressure-retaining drainage hole 1c.

[0046] Furthermore, the drilling fluid pressure in the cylinder 1 is higher than the drilling fluid pressure outside the cylinder 1 , and since the pressure-holding drainage hole 1 c is blocked, the drilling fluid in the cylinder 1 cannot be connected to the outside of the cylinder 1 .

[0047] The one-flow valve seat 8 is provided with a valve seat hollow flow channel 8a, a conical surface 8b and a hexagonal surface 8c. The valve seat hollow flow channel 8a is used to discharge drilling fluid to the central flow channel 5f of the power shaft when the core moves upward, the conical surface 8b is used to set the sealing ball 7, and the hexagonal surface 8c is used for installation and removal of the one-flow valve seat 8.

[0048] Furthermore, during normal drilling, the sealing ball 7 stays on the conical surface 8b of the single-flow valve seat 8 under the action of its own weight, thereby blocking the hollow flow channel 8a of the valve seat, preventing the drilling fluid pressure from directly acting on the upper surface of the core.

[0049] The core claw 9 is provided with a core claw male buckle 9a, a claw block 9b and a slip tooth 9c. The core claw male buckle 9a is connected to the cylinder 1, the claw blocks 9b are evenly distributed around the core claw 9, longitudinal grooves are provided between the claw blocks 9b, and the slip teeth 9c are used to grasp the core.

[0050] Furthermore, due to the provision of the longitudinal grooves between the claw blocks 9b, the lower ends of the claw blocks 9b of the core claw 9 can be contracted to grip the outer surface of the core column.

[0051] The coring drill bit 10 is provided with a slope surface 10a, a hollow coring section 10b and a drill bit drainage channel 10c. When the claw block 9b slides along the slope surface 10a, the slip teeth 9c on the claw block 9b will clamp the core. The inner diameter of the hollow coring section 10b is the same as the outer diameter of the core to be taken.

[0052] The inner diameter of the core claw 9 is the same as the inner diameter of the power shaft core cavity 5d and is 1-3 mm smaller than the inner diameter of the core drill bit 10.

[0053] Furthermore, the diameter of the core taken is determined by the inner diameter of the core bit 10. To reduce the friction of the core column in the core claw 9 and the core cavity 5d of the power shaft, the outer diameter of the core column is slightly smaller than the inner diameter of the core claw 9 and the core cavity 5d of the power shaft.

[0054] During normal coring drilling, the drilling pressure and torque transmitted by the upper drill string are transmitted to the coring drill bit 10 through the barrel 1. The drilling fluid flowing from the upper drill string to the barrel 1 flows through the mandrel central flow channel 4c, the mandrel branch flow channel 4d, the annular flow channel between the outer wall of the mandrel 4 and the inner wall of the barrel 1, and the drill bit drainage channel 10c in sequence. The coring drill bit 10 grinds the formation under the action of the drilling pressure and torque, and the formed core enters the hollow coring section 10b of the coring drill bit 10. During this process, the drilling fluid in the core cavity 5d of the power shaft passes through the hollow flow channel 8a of the valve seat, and after pushing open the sealing ball 8, flows to the central flow channel 5f of the power shaft and the side discharge hole 5b of the power shaft, and flows to the annulus formed by the outer wall of the power shaft 5 and the inner wall of the cylinder 1; when it is necessary to cut the core, a steel ball 11 with a diameter larger than the inner diameter of the central flow channel 4c of the mandrel is dropped from the ground into the drill string, and the steel ball 11 blocks the central flow channel 4c of the mandrel and holds the pressure, and the mandrel is cut under the action of the drilling fluid pressure. 4 and the barrel 1 are sheared off, the mandrel 4 moving downward compresses the spring 6 and pushes the power shaft 5 and the core claw 9 to move downward, the claw block 9b on the core claw 9 slides on the slope surface 10a of the coring drill bit 10 and shrinks inward, the slip teeth 9c on the claw block 9b clamp the core and then lift the drill string to pull the core off; in the process of cutting the core, when the shear pin 3 is sheared off and the mandrel 4 moves downward, the pressure-holding drainage hole 1c blocked during normal drilling will be unblocked, so that the inside and outside of the barrel are connected to avoid abnormal high pressure; when drilling is abnormal, such as the core is stuck in the core claw 9 or the power shaft 5d, the core will push the core claw 9 and the power shaft 5d to overcome the pressure of the spring 6 and move upward, further making the power shaft plunger 5a slide in the mandrel plunger cavity 4e and block the mandrel diversion channel 4d, so that the surface pump pressure increases rapidly, thereby monitoring the drilling status.

[0055] The specific implementation methods described above are used to illustrate the present invention rather than to limit the scope of the present invention. Any equivalent changes and modifications made by technicians in this field without departing from the concept and principle of the present invention are within the protection scope of the system of the present invention.

Claims

1. A method for coring a tool for oil and gas drilling, characterized in that: The oil and gas drilling coring tool comprises a barrel (1), a sealing ring (2), a shear pin (3), a spindle (4), a power shaft (5), a spring (6), a sealing ball (7), a check valve seat (8), a core claw (9) and a coring drill bit (10), characterized in that the upper part of the barrel (1) is connected to a drill string, the lower end of the barrel (1) is connected to the coring drill bit (10) by a thread, the sealing ring (2) is arranged between the outer wall of the spindle (4) and the inner wall of the barrel (1), one end of the shear pin (3) is inserted into the spindle (4) and the other end is fixed on the barrel (1), a spring (6) is arranged between the spindle (4) and the power shaft (5), and a screw thread is formed on the barrel (1). 6), a check valve seat (8) is fixed inside the power shaft (5) by means of threads, a sealing ball (7) is provided between the check valve seat (8) and the power shaft (5), and the lower end of the power shaft (5) is connected to the upper end of the core claw (9) by means of threads; the cylinder (1) is provided with a housing female buckle (1a), a pin threaded hole (1b), a pressure-holding drainage hole (1c) and a housing male buckle (1d), the housing female buckle (1a) connects the cylinder (1) to the upper drill string, the number of the pin threaded holes (1b) is two and symmetrically distributed, the number of the pressure-holding drainage holes (1c) is two and symmetrically distributed, and the housing male buckle (1d) connects the cylinder (1) is connected to a core drill bit (10); the mandrel (4) is provided with a sealing ring groove (4a), a pin mounting ring groove (4b), a mandrel central flow channel (4c), a mandrel branch flow channel (4d), a mandrel plunger cavity (4e) and a mandrel spring cavity (4f); the drilling fluid flowing into the mandrel central flow channel (4c) flows to the outside of the mandrel (4) through the mandrel branch flow channel (4d); one end of the shear pin (3) is fixed in the pin threaded hole (1b) of the barrel (1) by a thread and the other end is inserted into the pin mounting ring groove (4b); the sealing ring (2) is arranged in the sealing ring groove (4a); the power shaft (5) is provided with a power shaft A plunger (5a), a power shaft side hole (5b), a valve seat connecting buckle (5c), a power shaft core cavity (5d) and a power shaft female buckle (5e); the upper end of the power shaft plunger (5a) is inserted into the spindle plunger cavity (4e); the spring (6) is sleeved outside the power shaft plunger (5a) and the spring (6) is placed in the spindle plunger cavity (4e); the check valve seat (8) is connected to the valve seat connecting buckle (5c) by threads; the sealing ball (7) is arranged in the power shaft central flow channel (5f); after the spindle (4) is installed in the cylinder (1) through the shear pin (3), the spindle (4) blocks the pressure-holding drainage hole (1c);During normal coring drilling, the drilling pressure and torque transmitted by the upper drill string are transmitted to the coring drill bit (10) through the barrel (1). The drilling fluid flowing from the upper drill string to the barrel (1) flows in sequence through the mandrel central flow channel (4c), the mandrel branch flow channel (4d), the annular flow channel between the outer wall of the mandrel (4) and the inner wall of the barrel (1), and the drill bit drainage channel (10c). The coring drill bit (10) grinds the formation under the action of the drilling pressure and torque, and the formed core enters the hollow coring section (10b) of the coring drill bit (10). During this process, the drilling fluid in the core cavity (5d) of the power shaft passes through the hollow flow channel (8a) of the valve seat, and after pushing open the sealing ball (7), flows to the central flow channel (5f) of the power shaft and the side discharge hole (5b) of the power shaft, and flows to the annulus formed by the outer wall of the power shaft (5) and the inner wall of the cylinder (1); when it is necessary to cut the core, a steel ball (11) with a diameter larger than the inner diameter of the central flow channel (4c) of the mandrel is dropped into the drill string from the ground, and the steel ball (11) blocks the central flow channel (4c) of the mandrel and holds the pressure, and the mandrel (4) is opened under the action of the drilling fluid pressure. The shear pin (3) between the core and the barrel (1) is sheared off, the mandrel (4) moving downward compresses the spring (6) and pushes the power shaft (5) and the core claw (9) to move downward, the claw block (9b) on the core claw (9) slides on the slope surface (10a) of the coring drill bit (10) and shrinks inward, the slip teeth (9c) on the claw block (9b) clamp the core and then lift the drill string to pull the core apart; during the core cutting process, when the shear pin (3) is sheared off and the mandrel (4) moves downward, the normal drilling is carried out. The blocked pressure drain hole (1c) during drilling will be unblocked, so that the inside and outside of the cylinder are connected to avoid abnormal high pressure; when drilling abnormalities occur, such as when the core is stuck in the core claw (9) or the power shaft core cavity (5d), the core will push the core claw (9) and the power shaft (5) to move upward against the pressure of the spring (6), further causing the power shaft plunger (5a) to slide in the mandrel plunger cavity (4e) and block the mandrel diversion channel (4d), so that the surface pump pressure increases rapidly, thereby monitoring the drilling status. ; 2. A method of an oil and gas drilling coring tool according to claim 1, characterized in that: The one-flow valve seat (8) is provided with a valve seat hollow flow channel (8a), a conical surface (8b) and a hexagonal surface (8c); the valve seat hollow flow channel (8a) is used to discharge drilling fluid to the central flow channel (5f) of the power shaft when the core moves upward; the conical surface (8b) is used to set the sealing ball (7); and the hexagonal surface (8c) is used for installing and removing the one-flow valve seat (8).

3. The method of an oil and gas drilling coring tool according to claim 1, characterized in that: The core claw (9) is provided with a core claw male buckle (9a), a claw block (9b) and a slip tooth (9c); the core claw male buckle (9a) is connected to the barrel (1); the claw blocks (9b) are evenly distributed around the core claw (9); longitudinal grooves are provided between the claw blocks (9b); and the slip tooth (9c) is used for gripping the core.

4. The method of an oil and gas drilling coring tool according to claim 1, characterized in that: The coring drill bit (10) is provided with a slope surface (10a), a hollow coring section (10b) and a drill bit drainage channel (10c) inside. When the claw block (9b) slides along the slope surface (10a), the slip teeth (9c) on the claw block (9b) will clamp the core. The inner diameter of the hollow coring section (10b) is the same as the outer diameter of the core to be taken.

5. The method of an oil and gas drilling coring tool according to claim 1, characterized in that: The inner diameter of the core claw (9) is the same as the inner diameter of the power shaft core cavity (5d) and is 1-3 mm smaller than the inner diameter of the core drill bit (10).

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