CN117365347A - Oil-gas drilling coring tool and method - Google Patents

Abstract

The invention discloses an oil and gas drilling coring tool and method, wherein the device comprises a barrel, a sealing ring, a shear pin, a mandrel, a power shaft, a spring, a sealing ball, a uniflow valve seat, a core claw and a coring bit; when a core needs to be cut, a steel ball with the diameter larger than the inner diameter of the central runner of the mandrel is thrown into the drill string from the ground, the steel ball plugs and presses the central runner of the mandrel, a shearing pin between the mandrel and the cylinder body is sheared under the action of drilling fluid pressure, the mandrel moving downwards compresses a spring and pushes a power shaft and a core claw to move downwards, a claw block on the core claw slides on the slope surface of the core bit and contracts inwards, and slip teeth on the claw block lift the drill string after clamping the core, so that the core can be broken.

Description

Oil and gas drilling coring tool and method

Technical field

The invention relates to an downhole tool, specifically an oil and gas drilling coring tool and method, and belongs to the technical field of mechanical engineering or drilling engineering.

Background technique

In oil and gas exploration, the properties of underground rock formations are the key to judging the quality of oil fields. Since rock formations storing oil and gas are usually buried deep underground, conventional detection methods are difficult to directly detect the properties of underground rock formations. Usually, the exploration method of underground rock formations is to take out rock formation samples from the formation through drilling and coring tools. The taken out rock formation samples are called cores, and then the taken out cores are analyzed and processed. Through the detection of the cores, the sedimentary characteristics and rock formation characteristics of the rock formations can be determined. Characteristics, oil, gas, water and other characteristics as well as underground structure conditions, intuitively study the underground structure and rock deposition environment, and understand the mineral storage conditions in it. Through the analysis and research of cores, reasonable and scientific oil and gas development plans can be formulated and the efficiency of oil and gas extraction can be improved.

Drilling and coring tools are important equipment widely used in stratigraphic survey. 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 coring purpose; according to the tool structure, they can be divided into single-cylinder coring tools and double-cylinder coring tools; according to the classification of core-cutting force It is a self-locking, pressurized, differential and sand card coring tool. Coring is mainly divided into two operations. The first is to drill down with a ring drill bit, and a cylindrical rock column is formed in the inner barrel; the second is to cut the core out when the core is formed to a certain length. In the conventional coring process, as the drilling tool goes down, the core enters the inner barrel. Due to the complexity of the underground rock formation, during the coring process, the core may be damaged in the inner barrel due to the long core and low core structural strength. Bend or collapse, causing the core to come into contact with the inner cylinder, causing the inner cylinder to be blocked, and the core cannot continue to be formed normally. If the coring tool continues to drill after the blockage occurs, it will cause irreversible damage to the coring tool. damage, so there is an urgent need for a coring tool that can detect coring blockage during coring.

Contents of the invention

The purpose of the present invention is to propose an oil and gas drilling coring tool and method, which can be used to achieve the purpose of safe and efficient coring for formation evaluation.

The technical solution adopted by the present invention is:

An oil and gas drilling coring tool, including a cylinder, a sealing ring, a shear pin, a mandrel, a power shaft, a spring, a sealing ball, a one-flow valve seat, a core claw and a coring bit. The upper part of the cylinder is in contact with the drill bit. Column connection, the lower end of the cylinder is connected to the core drill bit through a thread, the sealing ring is provided between the outer wall of the mandrel and the inner wall of the cylinder, one end of the shear pin is inserted into the mandrel and the other end is fixed to the cylinder There is a spring between the mandrel and the power shaft. The one-flow valve seat is fixed inside the power shaft through threads. There is a sealing ball between the one-flow valve seat and the power shaft. The lower end of the power shaft and the upper end of the core claw Through threaded connection.

The barrel is provided with a housing female button, a pin threaded hole, a pressure holding drain hole and a housing male button. The housing female button connects the barrel to the upper drill string. The number of the pin threaded holes is 2 and symmetrically distributed, the number of the pressure-holding drainage holes is 2 and symmetrically distributed, and the housing male button connects the cylinder and the coring drill bit.

The mandrel is provided with a sealing ring groove, a pin mounting ring groove, a mandrel center flow channel, a mandrel shunt channel, a mandrel plunger cavity and a mandrel spring cavity. The drilling fluid flowing into the mandrel center flow channel passes through The shunt channel of the mandrel flows to the outside of the mandrel; one end of the shear pin is threaded in the pin thread hole of the cylinder and the other end is inserted into the pin installation ring groove; the sealing ring is located in the sealing ring groove.

The power shaft is provided with a power shaft plunger, a power shaft side row hole, a valve seat connection buckle, a power shaft core cavity and a power shaft mother buckle. The upper end of the power shaft plunger is inserted into the mandrel plunger cavity. The spring is set outside the power shaft plunger and the spring is placed in the mandrel plunger cavity. The single-flow valve seat and the valve seat connection buckle are connected through threads. The sealing ball is located in the central flow channel of the power shaft.

Further, when the coring tool is working, the spring is in a pre-tightened state.

Further, 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 dynamic shaft jointly act on the dynamic shaft to overcome the friction of the core column on the dynamic shaft.

After the mandrel is installed inside the cylinder through the shear pin, the mandrel will block the pressure drain hole.

Furthermore, the drilling fluid pressure inside the cylinder is higher than the drilling fluid pressure outside the cylinder. Since the pressure-holding drainage hole is blocked, the drilling fluid inside the cylinder cannot communicate with the outside of the cylinder.

The single-flow valve seat is provided with a hollow flow channel, a conical surface and a hexagonal surface. The hollow flow channel of the valve seat 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 a seal. The ball and the hexagon are used for the installation and removal of the single-flow valve seat.

Furthermore, during normal drilling, the sealing ball stays on the conical surface of the single-flow valve seat under 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.

The core claws are provided with core claw male buckles, claw blocks and slip teeth. The core claw male buckles are connected to the cylinder body. The claw blocks are evenly distributed around the core claws. There are longitudinal grooves between the claw blocks. Shukawa teeth are used to grip the core.

Furthermore, due to the arrangement of longitudinal grooves between the claw blocks, the lower ends of the claw blocks of the core claws can contract to grasp the outer surface of the core column.

The interior of the coring 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 slips on the claw block will clamp the core. The inner diameter of the hollow coring section is the same as that of the drill bit. The outer diameters of the cores taken are the same.

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 coring bit.

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

During normal coring drilling, the drilling pressure and torque transmitted by the upper drill string are transmitted to the coring bit through the barrel. The drilling fluid flowing from the upper drill string to the barrel sequentially flows through the mandrel central flow channel, the mandrel branch channel, and the The annular flow channel and drill bit drainage channel between the outer wall of the mandrel and the inner wall of the cylinder, the coring bit grinds the formation under the action of drilling pressure and torque, and the formed core enters the hollow coring section of the coring bit. During this process The drilling fluid in the core cavity of the middle power shaft passes through the hollow flow channel of the valve seat, and after pushing away the sealing ball, flows to the central flow channel of the power shaft and the side row holes of the power shaft and flows to the annulus composed of the outer wall of the power shaft and the inner wall of the cylinder; when needed When cutting the core, a steel ball with a diameter larger than the inner diameter of the mandrel center flow channel is thrown into the drill string from the ground. The steel ball blocks the mandrel center flow channel and suppresses the pressure. Under the action of drilling fluid pressure, the shear between the mandrel and the cylinder is The pin is sheared, and the downward moving mandrel compresses the spring and pushes the power shaft and core claw to move downward. The claw block on the core claw slides on the slope surface of the coring bit and contracts inward. The slips on the claw block The teeth clamp the core and then lift the drill string to pull the core off; during the core cutting process, when the shear pin is sheared and the mandrel moves downward, the pressure-draining liquid that is blocked during normal drilling will The hole will be unsealed to connect the inside and outside of the barrel to avoid abnormal high pressure; when drilling is abnormal, such as when the core is stuck in the core claw or the power shaft, the core will push the core claw and the power shaft to move upward against the pressure of the spring. Further, the power shaft plunger slides in the mandrel plunger cavity and blocks the mandrel shunt channel, causing the surface pump pressure to rise rapidly, so that the drilling status can be monitored.

Compared with the prior art, the beneficial effects of the present invention are: (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 hold back pressure. , so that the underground drilling situation can be determined by measuring the surface pressure; (2) The present invention does not contain 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 .

Description of the drawings

Figure 1 is a schematic structural diagram of an oil and gas drilling coring tool according to the present invention;

Figure 2 is a schematic structural diagram of an oil and gas drilling coring tool according to the present invention during normal coring;

Figure 3 is a schematic structural diagram of an oil and gas drilling coring tool according to the present invention when it is clogged;

Figure 4 is a schematic structural diagram of the barrel of an oil and gas drilling coring tool according to the present invention;

Figure 5 is another structural schematic diagram of the barrel of an oil and gas drilling coring tool according to the present invention;

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

Figure 7 is another structural schematic diagram of the mandrel of an oil and gas drilling coring tool according to the present invention;

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

Figure 9 is another structural schematic diagram of a power shaft of an oil and gas drilling coring tool according to the present invention;

Figure 10 is a schematic structural diagram of a single-flow valve seat of an oil and gas drilling coring tool according to the present invention;

Figure 11 is a schematic structural diagram of the core claw of an oil and gas drilling coring tool according to the present invention;

Figure 12 is another structural schematic diagram of the core claw of an oil and gas drilling coring tool according to the present invention;

Figure 13 is a schematic structural diagram of a coring bit of an oil and gas drilling coring tool according to the present invention;

In the picture: 1-cylinder, 1a-shell female buckle, 1b-pin threaded hole, 1c-pressure drain hole, 1d-shell male buckle, 2-sealing ring, 3-shear pin, 4-center Shaft, 4a-seal ring groove, 4b-pin mounting ring groove, 4c-arbor center flow channel, 4d-arbor branch channel, 4e-arbor plunger chamber, 4f-arbor spring chamber, 5-power shaft, 5a-power shaft plunger, 5b-power shaft side row hole, 5c-valve seat connection buckle, 5d-power shaft core cavity, 5e-power shaft female buckle, 6-spring, 7-sealing ball, 8-check 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-slip teeth, 10-coring bit, 10a- Slope surface, 10b-hollow coring section, 10c-drill bit drainage channel.

Detailed ways

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

Example:

As shown in Figures 1 to 13, an oil and gas drilling coring tool includes a cylinder 1, a sealing ring 2, a shear pin 3, a mandrel 4, a power shaft 5, a spring 6, a sealing ball 7, and a single-flow valve seat. 8. Core claw 9 and coring 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 threadedly connected to the coring bit 10, and the sealing ring 2 is arranged on the mandrel. Between the outer wall of 4 and the inner wall of the cylinder 1, one end of the shear pin 3 is inserted into the mandrel 4 and the other end is fixed on the cylinder 1. A spring 6 is provided between the mandrel 4 and the power shaft 5, and a one-flow valve The seat 8 is fixed inside the power shaft 5 through threads. A sealing ball 7 is provided between the one-flow valve seat 8 and the power shaft 5. The lower end of the power shaft 5 is connected to the upper end of the core claw 9 through threads.

The barrel 1 is provided with a housing female button 1a, a pin threaded hole 1b, a pressure drain hole 1c and a housing male button 1d. The housing female button 1a connects the barrel 1 to the upper drill string, so The number of the pin threaded holes 1b is 2 and symmetrically distributed. The number of the pressure-holding drain holes 1c is 2 and symmetrically distributed. The housing pin 1d connects the cylinder 1 to the coring drill bit 10 .

The spindle 4 is provided with a sealing ring groove 4a, a pin mounting ring groove 4b, a spindle center flow channel 4c, a spindle branch channel 4d, a spindle plunger cavity 4e and a spindle spring cavity 4f, which flow into the spindle. The drilling fluid in the central flow channel 4c flows to the outside of the mandrel 4 through the mandrel branch channel 4d; one end of the shear pin 3 is threaded in the pin thread hole 1b of the barrel 1 and the other end is inserted into the pin mounting ring groove 4b; The sealing ring 2 is located in the sealing ring groove 4a.

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 core. The shaft plunger cavity 4e, the spring 6 is set outside the power shaft plunger 5a and the spring 6 is placed in the spindle plunger cavity 4e, the single-flow valve seat 8 and the valve seat connection buckle 5c are connected through threads, the The sealing ball 7 is located in the central flow channel 5f of the power shaft.

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

Further, 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 jointly act on the power shaft 5 to overcome the friction of the core column on the power shaft.

After the mandrel 4 is installed inside the cylinder 1 through the shear pin 3, the mandrel 4 will block the pressure discharge hole 1c.

Furthermore, the drilling fluid pressure inside the cylinder 1 is higher than the drilling fluid pressure outside the cylinder 1. Since the pressure-holding drainage hole 1c is blocked, the drilling fluid inside the cylinder 1 cannot communicate with the outside of the cylinder 1.

The single-flow valve seat 8 is provided with a valve seat hollow channel 8a, a cone surface 8b and a hexagonal surface 8c. The valve seat hollow channel 8a is used to discharge drilling fluid to the power shaft center channel 5f when the core moves upward. The cone surface 8b is used to set the sealing ball 7, and the hexagonal surface 8c is used to install and disassemble the single-flow valve seat 8.

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

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. The claw blocks There are longitudinal grooves between 9b, and the slips 9c are used to grasp the core.

Furthermore, due to the arrangement of longitudinal grooves between the claw blocks 9b, the lower ends of the claw blocks 9b of the core claws 9 can contract to grasp the outer surface of the core column.

The coring 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 slips 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 taken.

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 coring bit 10.

Further, the diameter of the core taken is determined by the inner diameter of the core drill bit 10. In order to reduce the friction of the core column in the core claw 9 and the power shaft core cavity 5d, the outer diameter of the core column is slightly smaller than the core claw 9 and the power shaft core cavity 5d. 5d inner diameter.

During normal coring drilling, the drilling pressure and torque transmitted by the upper drill string are transmitted to the coring bit 10 through the barrel 1. The drilling fluid flowing from the upper drill string to the barrel 1 flows through the mandrel center flow channel 4c and the mandrel in sequence. The split channel 4d, the annular flow channel between the outer wall of the mandrel 4 and the inner wall of the cylinder 1, and the drill bit drainage channel 10c, the coring bit 10 grinds the formation under the action of drilling pressure and torque, and the formed core enters the coring bit 10 In the hollow coring section 10b, during this process, the drilling fluid in the power shaft core cavity 5d passes through the valve seat hollow flow channel 8a, and after pushing away the sealing ball 8, flows to the power shaft center flow channel 5f and the power shaft side row hole 5b. The flow direction is the annulus composed of 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 mandrel center flow channel 4c is thrown into the drill string from the ground, and the steel ball 11 will flow into the center of the mandrel. Channel 4c is blocked and pressurized. Under the action of drilling fluid pressure, the shear pin 3 between the mandrel 4 and the cylinder 1 is sheared. The downward moving mandrel 4 compresses the spring 6 and pushes the power shaft 5 and the core claw 9 downward. movement, the claw block 9b on the core claw 9 slides on the slope surface 10a of the coring bit 10 and contracts inward. The slips 9c on the claw block 9b clamp the core and lift the drill string, and the core can be Pull off; during the core cutting process, when the shear pin 3 is sheared and the mandrel 4 moves downward, the pressure drain hole 1c that was blocked during normal drilling will be unsealed, allowing the inside and outside of the cylinder to be connected to avoid Abnormally high pressure; when drilling is abnormal, such as when 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 move upward against the pressure of the spring 6, further causing the power shaft plunger 5a It slides in the mandrel plunger chamber 4e and blocks the mandrel shunt channel 4d, causing the surface pump pressure to rise rapidly, so that the drilling status can be monitored.

The above-described specific embodiments are used to illustrate the present invention but not to limit the scope of the present invention. Any equivalent changes and modifications made by those skilled in the art without departing from the concept and principles of the present invention all belong to the system of the present invention. scope of protection.

Claims (10)

1. The utility model provides an oil gas drilling coring tool, includes barrel (1), sealing washer (2), shear pin (3), mandrel (4), power shaft (5), spring (6), sealing ball (7), uniflow disk seat (8), rock core claw (9) and coring bit (10), its characterized in that, the upper portion and the drilling string of barrel (1) are connected, and threaded connection is passed through with coring bit (10) in the lower extreme of barrel (1), sealing washer (2) set up between the outer wall of mandrel (4) and the inner wall of barrel (1), shear pin (3) one end is inserted in mandrel (4) and the other end is fixed in on barrel (1), is equipped with spring (6) between mandrel (4) and power shaft (5), uniflow disk seat (8) are equipped with sealing ball (7) through threaded connection inside power shaft (5) between uniflow disk seat (8) and power shaft (5), the lower extreme and the upper end of rock core claw (9) pass through threaded connection.

2. The oil and gas drilling coring tool according to claim 1, wherein a shell box (1 a), pin threaded holes (1 b), a pressure-holding drain hole (1 c) and a shell pin (1 d) are arranged on the barrel (1), the shell box (1 a) is used for connecting the barrel (1) with an upper drill string, the number of the pin threaded holes (1 b) is 2 and symmetrically distributed, the number of the pressure-holding drain holes (1 c) is 2 and symmetrically distributed, and the shell pin (1 d) is used for connecting the barrel (1) with a coring drill bit (10).

3. An oil and gas drilling coring tool according to claim 1, wherein the mandrel (4) is provided with a sealing ring groove (4 a), a pin mounting ring groove (4 b), a mandrel central runner (4 c), a mandrel sub-runner (4 d), a mandrel plunger cavity (4 e) and a mandrel spring cavity (4 f), and the drilling fluid flowing into the mandrel central runner (4 c) flows to the outside of the mandrel (4) through the mandrel sub-runner (4 d); one end of the shear pin (3) is fixed in a pin threaded hole (1 b) of the cylinder body (1) through threads, and the other end of the shear pin is inserted into a pin installation ring groove (4 b); the sealing ring (2) is arranged in the sealing ring groove (4 a).

4. The oil and gas drilling coring tool according to claim 1, wherein a power shaft plunger (5 a), a power shaft side hole (5 b), a valve seat connecting buckle (5 c), a power shaft core cavity (5 d) and a power shaft box (5 e) are arranged on the power shaft (5), the upper end of the power shaft plunger (5 a) is inserted into the mandrel plunger cavity (4 e), the spring (6) is sleeved outside the power shaft plunger (5 a) and the spring (6) is placed in the mandrel plunger cavity (4 e), the single-flow valve seat (8) is connected with the valve seat connecting buckle (5 c) through threads, and the sealing ball (7) is arranged in the power shaft central flow passage (5 f).

5. The oil and gas drilling coring tool according to claim 1, wherein after the mandrel (4) is installed inside the cylinder (1) through the shear pin (3), the mandrel (4) seals the pressure-holding drain hole (1 c).

6. The oil and gas drilling coring tool according to claim 1, wherein the uniflow valve seat (8) is provided with a valve seat hollow flow passage (8 a), a conical surface (8 b) and a hexagonal (8 c), the valve seat hollow flow passage (8 a) is used for discharging drilling fluid to a power shaft central flow passage (5 f) when a core moves upwards, the conical surface (8 b) is used for arranging a sealing ball (7), and the hexagonal (8 c) is used for mounting and dismounting the uniflow valve seat (8).

7. The oil and gas drilling coring tool according to claim 1, wherein core claws (9) are provided with core claw pin buttons (9 a), claw blocks (9 b) and slip teeth (9 c), the core claw pin buttons (9 a) are connected with the cylinder body (1), the claw blocks (9 b) are uniformly distributed around the core claws (9), longitudinal grooves are arranged between the claw blocks (9 b), and the slip teeth (9 c) are used for gripping a core.

8. An oil and gas drilling coring tool as in claim 1, wherein the coring bit (10) has a ramp surface (10 a), a hollow coring section (10 b) and a bit drain (10 c) inside, and the slip teeth (9 c) on the jaw (9 b) clamp the core as the jaw (9 b) slides along the ramp surface (10 a), the hollow coring section (10 b) having an inner diameter equal to the outer diameter of the core being cored.

9. An oil and gas drilling coring tool according to claim 1, wherein the core grip (9) has an inner diameter equal to the inner diameter of the power shaft core cavity (5 d) and 1-3mm smaller than the inner diameter of the coring bit (10).

10. The method of an oil and gas drilling coring tool according to claim 1, wherein during normal coring drilling, the weight and torque transmitted by the upper drill string are transmitted to the coring bit (10) through the cylinder (1), the drilling fluid flowing from the upper drill string to the cylinder (1) flows through the mandrel central flow passage (4 c), the mandrel sub-flow passage (4 d), the annular flow passage between the outer wall of the mandrel (4) and the inner wall of the cylinder (1), the bit fluid drain passage (10 c), the coring bit (10) grinds the stratum under the action of the weight and torque, the formed core enters the hollow coring section (10 b) of the coring bit (10), during which the drilling fluid flowing from the power shaft core cavity (5 d) through the valve seat hollow flow passage (8 a) flows to the power shaft central flow passage (5 f) and the shaft side vent hole (5 b) after pushing away the sealing ball (8) and flows to the annular space formed by the outer wall of the shaft (5) and the inner wall of the cylinder (1); when a core needs to be cut, a steel ball (11) with the diameter larger than the inner diameter of a mandrel central runner (4 c) is thrown into a drill string from the ground, the steel ball (11) plugs and presses the mandrel central runner (4 c), a shear pin (3) between the mandrel (4) and a cylinder body (1) is sheared under the action of drilling fluid pressure, the mandrel (4) which moves downwards compresses a spring (6) and pushes a power shaft (5) and a core claw (9) to move downwards, a claw block (9 b) on the core claw (9) slides on a slope surface (10 a) of a core drill bit (10) and contracts inwards, and a slip tooth (9 c) on the claw block (9 b) clamps a core and lifts the drill string, so that the core can be pulled off; in the heart cutting process, when the shearing pin (3) is sheared off and the mandrel (4) moves downwards, the blocked pressure-holding liquid discharge hole (1 c) is unsealed in normal drilling, so that the internal and external communication of the cylinder body is avoided to generate abnormal high pressure; when an abnormality occurs in drilling, such as a rock core is clamped in a rock core claw (9) or a power shaft (5 d), the rock core pushes the rock core claw (9) and the power shaft (5 d) to move upwards against the pressure of a spring (6), a power shaft plunger (5 a) further slides in a mandrel plunger cavity (4 e) and blocks a mandrel runner (4 d), so that the ground pumping pressure is rapidly increased, and the drilling state can be monitored.