Pressure-maintaining coring device and coring method for resource exploration sampling

Abstract

The invention relates to the technical field of rock drilling, and discloses a pressure-maintaining coring device and a coring method for resource exploration sampling. The pressure-maintaining coring device comprises an outer cylinder, a drill bit installed at the end of the outer cylinder, an inner cylinder installed in the outer cylinder and a differential joint; a high-pressure air chamber, a fixed plug, a compensation cabin, a floating piston, a rock core cavity, a ball valve and a closed liquid plug are sequentially arranged in the inner cylinder in the direction of the drill bit. The temperature detector and the driver are arranged on the fixing plug at the exhaust end of the high-pressure air chamber, in the rock core recovery process, for the situation that the internal pressure of a rock core cavity is changed due to external temperature change, the temperature detector triggers the driver after detecting the temperature change, the driver drives the baffle to move, and then the volume of the compensation cabin is changed; finally, the pressure in the rock core cavity can be changed, the pressure change caused by the temperature can be neutralized, the pressure in the rock core cavity is always kept stable, the preservation effect of the rock core is improved, and the subsequent rock core analysis result is more accurate.

Description

Technical Field

[0001] The invention relates to the technical field of rock drilling, in particular to a pressure-maintaining coring device and a coring method for resource exploration and sampling. Background Art

[0002] Sealed pressure-maintained coring is a special coring technology that can maintain or approach formation pressure, and can keep the fluid and gas in the core in their original state. The working principle of the pressure-maintained coring tool is as follows: before the coring tool is lowered into the well, the sealing fluid is pre-filled from the sealing fluid plug. During the drilling process, the sealing fluid can continuously wrap the core to protect it from drilling fluid contamination. When the coring drilling is completed, the drill tool is lifted up, and the retaining spring clamps the core. The ball valve is closed under the action of the differential assembly to achieve sealing of the core. The high-pressure gas chamber, the compensation gas valve and the balance chamber together form a pressure compensation assembly to achieve pressure compensation in the core tube and continuously maintain the internal pressure of the pressure-maintaining tube. However, the existing pressure-maintaining coring tools have certain shortcomings: the existing tools achieve pressure control by discharging the gas in the high-pressure gas chamber into the compensation chamber to keep the pressure in the core tube consistent with the pressure of the formation where it is located. During the process of moving the core tube up and out, the temperatures of different formations are different, and there is a temperature difference from underground to above ground. At different temperatures, the pressure will change, making the pressure in the core tube unstable and unable to be completely consistent with the pressure of the formation where the sampling is located, causing the properties of the sample to change, affecting the sample analysis results. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a pressure-maintaining coring device and a coring method for resource exploration and sampling, which have the advantages of good pressure-maintaining effect, and solve the problems of existing pressure-maintaining coring tools that, when lifting core samples, changes in different formation temperatures lead to pressure fluctuations, insufficient stability, and poor pressure-maintaining effect.

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions: a pressure-maintaining coring device, comprising an outer cylinder, a drill bit installed at the end of the outer cylinder, an inner cylinder installed inside the outer cylinder and a differential joint, wherein the inner cylinder is provided with a high-pressure gas chamber, a fixed plug, a compensation cabin, a floating piston, a core cavity, a ball valve and a sealing liquid plug in sequence in the direction of the drill bit, the fixed plug is fixed in the inner cylinder, a through hole is provided on the fixed plug, a compensation gas valve is installed on the through hole, a driving cavity is further provided inside the fixed plug, a straight hole is provided on the side wall of the driving cavity, the straight hole is connected to the compensation cabin, a baffle is installed inside the straight hole, and a driving assembly is installed on the side wall of the driving cavity;

[0005] The driving assembly is used to drive the baffle to move along the straight hole. The driving assembly includes a temperature detector and a transmission device. The temperature detector is used to detect the temperature of the outer wall of the inner tube. The transmission device is connected to the temperature detector and the baffle.

[0006] After the core is collected, the compensation gas valve operates to discharge the gas in the high-pressure gas chamber into the compensation cabin through the through hole, and pushes the floating piston to move, thereby adjusting the pressure in the core cavity to the rated value. When the core is taken out, the entire inner tube moves upward, and the temperature detector detects the formation temperature when the inner tube moves upward, and forces the transmission to operate. When the transmission operates, it drives the baffle to move along the straight hole. When the baffle moves, it regulates the air pressure in the compensation cabin, thereby regulating the pressure in the core cavity.

[0007] Preferably, the temperature detector comprises a hollow cylinder, which is fixedly embedded in the inner wall of the driving cavity, one end of the hollow cylinder extends to the outer wall of the inner cylinder and is fixed with a temperature-sensitive metal cover, a vertical piston is provided inside the hollow cylinder, a temperature-sensitive solution is injected between the vertical piston and the temperature-sensitive metal cover, a plug rod is fixedly connected to the vertical piston, one end of the plug rod passes through the end of the hollow cylinder and extends to the inside of the driving cavity, and the end of the plug rod away from the vertical piston is fixedly connected to the main pin rod.

[0008] Preferably, a return spring is sleeved on the outer side of the insertion rod, the return spring is located inside the hollow cylinder, and two ends of the return spring are respectively fixedly connected to the vertical piston and the inner wall of the hollow cylinder.

[0009] Preferably, both ends of the straight hole are fixedly connected with mounting rods, the baffle is slidably installed in the straight hole, the connection between the edge of the baffle and the inner wall of the straight hole is sealed, a transmission screw is provided inside the straight hole, the transmission screw passes through the baffle and is threadedly connected to the baffle, both ends of the transmission screw are rotatably connected to the two mounting rods respectively, and one end of the transmission screw extends into the inside of the drive cavity and is fixedly connected with a transmission gear.

[0010] Preferably, the transmission includes a longitudinal rotating shaft and a vertical slide rail, the vertical slide rail is fixed inside the driving cavity, a transmission rack is slidably connected to the vertical slide rail, the transmission rack is meshed with a transmission gear, a secondary pin rod is fixedly connected to the side wall of the transmission rack, and the secondary pin rod is parallel to the main pin rod.

[0011] Preferably, both ends of the longitudinal rotating shaft are fixed to the inner wall of the driving cavity, a lever is rotatably connected to the longitudinal rotating shaft, a strip hole is provided on the surface of the lever, and the main pin rod and the auxiliary pin rod are both inserted into the strip hole.

[0012] Preferably, a gas recovery assembly is installed on the baffle, and the gas recovery assembly is used to recover the gas in the compensation cabin to the inside of the high-pressure gas chamber. The gas recovery assembly includes a through hole arranged on the baffle and a first one-way valve installed in the through hole.

[0013] Preferably, the gas recovery assembly also includes a piston cylinder fixed to the side wall of the baffle, the piston cylinder is arranged on the side of the baffle close to the driving chamber and corresponds to the position of the through hole, a hose is fixedly connected to the side wall of the piston cylinder, one end of the hose is connected to the through hole, and a second one-way valve is installed at the connection between the hose and the piston cylinder.

[0014] Preferably, a driving motor is fixedly connected to the outer wall of the piston cylinder, a first bevel gear is fixed to the output shaft of the driving motor, a base shaft is provided at the end of the piston cylinder, the base shaft is installed on the end face of the piston cylinder through a bearing seat, a second bevel gear is fixed to one end of the base shaft, the second bevel gear is meshed with the first bevel gear, a turntable is fixed to the other end of the base shaft, a push rod is rotatably connected to the surface of the turntable near the edge, a driving piston is hinged at the other end of the push rod, and the driving piston is inserted into the piston cylinder.

[0015] The invention also discloses a coring method for resource exploration and sampling, and the coring method for resource exploration and sampling uses the above-mentioned pressure-maintaining coring device.

[0016] Compared with the prior art, the present invention provides a pressure-maintaining coring device and a coring method for resource exploration and sampling, which have the following beneficial effects:

[0017] 1. This type of pressure-maintaining coring device and the coring method for resource exploration and sampling, by arranging a temperature detector and a transmission on the fixed plug at the exhaust end of the high-pressure gas chamber, in the process of recovering the core, when the external temperature changes and the pressure inside the core cavity changes, the temperature detector triggers the transmission after detecting the temperature change, and the transmission then drives the baffle installed on the fixed plug to move, thereby changing the volume of the compensation chamber, and finally changing the pressure in the core cavity, and neutralizing the pressure change caused by temperature, so that the pressure in the core cavity is always kept stable, which is conducive to improving the preservation effect of the core and making the subsequent core analysis results more accurate.

[0018] 2. This type of pressure-maintaining coring device and the coring method for resource exploration sampling, by setting a gas recovery component, can recover the gas in the compensation chamber at the end of the sampling work. It has a high degree of automation, can prevent the loss and waste of gas in the compensation chamber, avoids repeated injection of large amounts of gas, saves costs, and reduces workload. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A cross-sectional view of a pressure-maintaining coring device of the present invention;

[0020] Figure 2 is a longitudinal cross-sectional view of the fixing plug of the present invention;

[0021] Figure 3 For the present invention Figure 2 A magnified view of part A;

[0022] Figure 4 It is a schematic diagram of the three-dimensional structure of the fixing plug of the present invention;

[0023] Figure 5 is a transverse cross-sectional view of the fixing plug of the present invention;

[0024] Figure 6 It is a schematic structural diagram of the transmission device of the present invention;

[0025] Figure 7 It is a three-dimensional structural schematic diagram of the baffle of the present invention;

[0026] Figure 8 It is a schematic structural diagram of the gas recovery component of the present invention.

[0027] In the figure: 1, outer cylinder; 2, drill bit; 3, inner cylinder; 4, differential joint; 5, drive assembly; 51, temperature detector; 511, hollow cylinder; 512, temperature-sensitive metal cover; 513, vertical piston; 514, temperature-sensitive solution; 515, plunger; 516, main pin rod; 517, return spring; 52, transmission; 521, longitudinal shaft; 522, vertical slide rail; 523, transmission rack; 524, auxiliary pin rod; 525, lever; 526, strip hole; 6, high-pressure gas chamber; 7, fixing plug; 71, through hole; 72, compensation air valve; 73, drive chamber ;74, straight hole;8, compensation cabin;9, floating piston;10, core chamber;11, ball valve;12, closed liquid plug;13, baffle;14, mounting rod;15, drive screw;16, drive gear;17, gas recovery assembly;171, through hole;172, first one-way valve;173, piston cylinder;174, hose;175, second one-way valve;176, drive motor;177, first bevel gear;178, base shaft;179, bearing seat;180, second bevel gear;181, turntable;182, push rod;183, drive piston. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] As introduced in the background technology, there are deficiencies in the prior art. In order to solve the above technical problems, the present application proposes a pressure-maintaining coring device and a coring method for resource exploration and sampling.

[0030] Example 1: Please refer to Figure 1-Figure 3A pressure-maintaining coring device comprises an outer cylinder 1, a drill bit 2 installed at the end of the outer cylinder 1, an inner cylinder 3 installed inside the outer cylinder 1 and a differential joint 4, wherein a high-pressure gas chamber 6, a fixed plug 7, a compensation chamber 8, a floating piston 9, a core chamber 10, a ball valve 11 and a sealing liquid plug 12 are sequentially arranged inside the inner cylinder 3 in the direction of the drill bit 2, the fixed plug 7 is fixed in the inner cylinder 3, a through hole 71 is formed on the fixed plug 7, a compensation gas valve 72 is installed on the through hole 71, a driving chamber 73 is further provided inside the fixed plug 7, a straight hole 74 is formed on the side wall of the driving chamber 73, the straight hole 74 is connected to the compensation chamber 8, a baffle 13 is installed inside the straight hole 74, and a driving assembly 5 is installed on the side wall of the driving chamber 73;

[0031] The driving assembly 5 is used to drive the baffle 13 to move along the straight hole 74. The driving assembly 5 includes a temperature detector 51 and a transmission device 52. The temperature detector 51 is used to detect the temperature of the outer wall of the inner tube 3. The transmission device 52 is connected between the temperature detector 51 and the baffle 13.

[0032] After the core is collected, the compensation gas valve 72 is operated to discharge the gas in the high-pressure gas chamber 6 into the compensation chamber 8 through the through hole 71, and push the floating piston 9 to move, thereby adjusting the pressure in the core cavity 10 to the rated value. When the core is taken out, the entire inner tube 3 moves up, and the temperature detector 51 detects the formation temperature when the inner tube 3 moves up, and forces the transmission device 52 to operate. When the transmission device 52 operates, it drives the baffle 13 to move along the straight hole 74. When the baffle 13 moves, it regulates the air pressure in the compensation chamber 8, thereby regulating the pressure in the core cavity 10.

[0033] Among them, the compensation gas valve 72, the floating piston 9, the ball valve 11 and the sealing liquid plug 12 are the same as those in the prior art. The high-pressure gas chamber 6 is filled with high-pressure nitrogen. The internal pressure of the high-pressure gas chamber 6 is greater than the formation pressure where the core is located. In the initial state, the core cavity 10 is filled with sealing liquid. The sealing liquid plug 12 is located in the drill bit 2. When collecting the core, the core pushes the sealing liquid plug 12 into the core cavity 10. The sealing liquid in the core cavity 10 overflows through the sealing liquid plug 12 and contacts with the core, thereby protecting the core.

[0034] During use, after the core is collected, the compensation gas valve 72 is operated to discharge the gas in the high-pressure gas chamber 6 into the compensation chamber 8 through the through hole 71. The gas pressure in the compensation chamber 8 increases, and then the floating piston 9 is pushed to move. After the floating piston 9 moves, the volume of the core cavity 10 is reduced, thereby increasing the pressure in the core cavity 10, so that the pressure in the core cavity 10 is consistent with the pressure of the formation where the core is located. The core is then taken out. When taking out, the entire inner tube 3 is lifted and moved upward. During the upward movement, the temperature of the formation changes, which easily causes the pressure in the core cavity 10 to change. At this time, the temperature detection The device 51 operates and detects the external temperature. When the temperature changes, the actuator 52 is triggered. After the actuator 52 operates, the baffle 13 is driven to move along the straight hole 74. When the baffle 13 moves along the straight hole 74, the volume of the compensation chamber 8 is changed, thereby causing the pressure in the compensation chamber 8 to change. When the pressure in the compensation chamber 8 changes, the floating piston 9 also moves accordingly. After the floating piston 9 moves, the volume in the core chamber 10 changes, and the pressure also changes accordingly. Therefore, in the process of recovering the core, the pressure in the core chamber 10 fluctuates to a certain extent with the external temperature change, and always keeps consistent with the pressure at the collection point.

[0035] By arranging a temperature detector 51 and a transmission device 52 on the fixed plug 7 at the exhaust end of the high-pressure gas chamber 6, during the core recovery process, if the external temperature changes and causes the internal pressure of the core cavity 10 to change, the temperature detector 51 triggers the transmission device 52 after detecting the temperature change, and the transmission device 52 then drives the baffle 13 installed on the fixed plug 7 to move, thereby changing the volume of the compensation chamber 8, and finally changing the pressure in the core cavity 10, and neutralizing the pressure change caused by temperature, so that the pressure in the core cavity 10 is always kept stable, which is beneficial to improving the preservation effect of the core and making the subsequent core analysis results more accurate.

[0036] Example 2: See Figure 1-Figure 3 , different from the above embodiment, the temperature detector 51 includes a hollow cylinder 511, which is fixedly embedded in the inner wall of the driving chamber 73, one end of the hollow cylinder 511 extends to the outer wall of the inner cylinder 3 and is fixed with a temperature-sensitive metal cover 512, a vertical piston 513 is provided inside the hollow cylinder 511, a temperature-sensitive solution 514 is injected between the vertical piston 513 and the temperature-sensitive metal cover 512, a plug rod 515 is fixedly connected to the vertical piston 513, one end of the plug rod 515 passes through the end of the hollow cylinder 511 and extends to the inside of the driving chamber 73, the end of the plug rod 515 away from the vertical piston 513 is fixedly connected to the main pin rod 516, a reset spring 517 is sleeved on the outer side of the plug rod 515, the reset spring 517 is located inside the hollow cylinder 511, and the two ends of the reset spring 517 are respectively fixedly connected to the vertical piston 513 and the inner wall of the hollow cylinder 511;

[0037] The temperature-sensitive metal cover 512 is preferably made of a metal material with high thermal conductivity. When the external temperature changes, the temperature is conducted to the temperature-sensitive solution 514 through the temperature-sensitive metal cover 512. The temperature-sensitive solution 514 expands or contracts under the temperature. When the temperature-sensitive solution 514 expands, the vertical piston 513 is driven to move. When the vertical piston 513 moves, it pushes the insertion rod 515 and the main pin rod 516 at the end of the insertion rod 515 to move. When the vertical piston 513 moves, it also compresses the spring.

[0038] By setting up the temperature detector 51, when the temperature increases, the volume of the temperature sensing solution 514 increases, thereby driving the main pin rod 516 to move. When the temperature decreases, the volume of the temperature sensing solution 514 decreases, and the main pin rod 516 is driven to move in the opposite direction under the action of the reset spring 517, which facilitates triggering the driver according to the temperature change outside the inner tube 3.

[0039] Example 3, see Figure 4-Figure 6 , which is different from the above embodiment, both ends of the straight hole 74 are fixedly connected with mounting rods 14, the baffle 13 is slidably installed in the straight hole 74, the edge of the baffle 13 and the inner wall of the straight hole 74 are sealed, and a transmission screw 15 is provided inside the straight hole 74, the transmission screw 15 passes through the baffle 13 and is threadedly connected to the baffle 13, and the two ends of the transmission screw 15 are respectively rotatably connected to the two mounting rods 14, one end of the transmission screw 15 extends into the driving cavity 73 and is fixedly connected with a transmission gear 16, and the transmission device 52 includes a longitudinal rotating shaft 521 and a vertical slide rail 522, the vertical slide rail 522 is fixed inside the driving cavity 73, a transmission rack 523 is slidably connected to the vertical slide rail 522, the transmission rack 523 is meshed with the transmission gear 16, a secondary pin rod 524 is fixedly connected to the side wall of the transmission rack 523, the secondary pin rod 524 is parallel to the main pin rod 516, both ends of the longitudinal rotating shaft 521 are fixed to the inner wall of the driving cavity 73, a lever 525 is rotatably connected to the longitudinal rotating shaft 521, a strip hole 526 is provided on the surface of the lever 525, the main pin rod 516 and the secondary pin rod 524 are both inserted into the strip hole 526;

[0040] The side wall of the straight hole 74 is provided with a plurality of slide grooves, the direction of which is consistent with the direction of the straight hole 74, and the edge of the baffle 13 is provided with a slider that slides with the slide groove, and the baffle 13 and the slider are fixedly covered with a rubber ring to achieve sealing;

[0041] When in use, the main pin rod 516 moves and pushes the inner wall of the strip hole 526, thereby causing the lever 525 to rotate around the longitudinal rotation axis 521. When the lever 525 rotates, the other end drives the auxiliary pin rod 524 to move, and the auxiliary pin rod 524 drives the transmission rack 523 to move along the vertical slide rail 522. When the transmission rack 523 moves, it drives the transmission gear 16 to rotate, and when the transmission gear 16 rotates, it drives the transmission screw 15 to rotate. When the transmission screw 15 rotates, it drives the baffle 13 to slide along the straight hole 74, so as to adjust the position of the baffle 13. After the position of the baffle 13 is adjusted, the body force of the compensation cabin 8 changes accordingly, and the pressure changes accordingly when the amount of internal gas remains unchanged;

[0042] By setting a driver, when the temperature detector 51 triggers the driver, the lever 525 is pushed to rotate, and then the transmission rack 523, the transmission gear 16, and the transmission screw 15 are used to drive the baffle 13 to move, and then the pressure of the compensation chamber 8 is controlled by adjusting the position of the baffle 13, and finally the pressure of the core cavity 10 can be adjusted according to the temperature.

[0043] Example 4, see Figure 2 , Figure 7 and Figure 8 , which is different from the above embodiment, a gas recovery component 17 is installed on the baffle 13, and the gas recovery component 17 is used to recover the gas in the compensation cabin 8 to the inside of the high-pressure gas chamber 6. The gas recovery component 17 includes a through hole 171 arranged on the baffle 13 and a first one-way valve 172 installed in the through hole 171. The gas recovery component 17 also includes a piston cylinder 173 fixed to the side wall of the baffle 13, and the piston cylinder 173 is arranged on the side of the baffle 13 close to the drive chamber 73 and corresponds to the position of the through hole 171. The side wall of the piston cylinder 173 is fixedly connected to a hose 174, one end of which is connected to the through hole 71, and the hose 174 is connected to the piston cylinder 173 A second one-way valve 175 is installed at the piston cylinder 173, a driving motor 176 is fixedly connected to the outer wall of the piston cylinder 173, and a first bevel gear 177 is fixed to the output shaft of the driving motor 176. A base shaft 178 is provided at the end of the piston cylinder 173, and the base shaft 178 is installed on the end surface of the piston cylinder 173 through a bearing seat 179. A second bevel gear 180 is fixed to one end of the base shaft 178, and the second bevel gear 180 is meshed with the first bevel gear 177. A turntable 181 is fixed to the other end of the base shaft 178, and a push rod 182 is rotatably connected to the surface of the turntable 181 near the edge, and a driving piston 183 is hinged at the other end of the push rod 182, and the driving piston 183 is inserted into the piston cylinder 173.

[0044] The through hole 171 is connected to the inner cavity of the piston cylinder 173, the first one-way valve 172 only allows the gas in the compensation chamber 8 to enter the piston cylinder 173 through the through hole 171, and the second one-way valve 175 only allows the gas in the piston cylinder 173 to enter the hose 174. The driving motor 176 is set as a servo motor. In the initial state, the driving piston 183 just blocks the end of the hose 174.

[0045] When in use, when the sampling work is finished, the driving motor 176 is started. When the driving motor 176 is running, it first drives the first bevel gear 177 to rotate a certain angle. When the first bevel gear 177 rotates, it drives the second bevel gear 180 to rotate. When the second bevel gear 180 rotates, it drives the base shaft 178 to rotate. When the base shaft 178 rotates, it drives the rotating disk 181 to rotate. When the rotating disk 181 rotates, it drives one end of the push rod 182 to move, forcing the other end of the push rod 182 to pull the driving piston 183. After the driving piston 183 moves, it no longer presses the hose 17 4 ends are blocked, and the gas in the compensation cabin 8 enters the high-pressure gas chamber 6 through the through hole 171, the piston cylinder 173, the hose 174 and the through hole 71. When the air pressure in the high-pressure gas chamber 6 is consistent with the air pressure in the compensation cabin 8, the drive motor 176 is started again, and the drive motor 176 controls the first bevel gear 177 to rotate continuously. When the first bevel gear 177 rotates continuously, it drives the piston to reciprocate, and the gas in the compensation cabin 8 is continuously sucked into the piston cylinder 173, and then continuously input into the high-pressure gas chamber 6, so as to realize gas recovery;

[0046] By setting up the gas recovery component 17, the gas in the compensation chamber 8 can be recovered at the end of the sampling work, which has a high degree of automation, can prevent the gas loss and waste in the compensation chamber 8, avoids repeated injection of large amounts of gas, saves costs, and reduces workload.

[0047] Embodiment 5, a coring method for resource exploration and sampling, this coring method for resource exploration and sampling, uses the pressure-maintaining coring device in the above embodiment, including core sampling and core recovery, wherein during the core recovery process, the pressure in the core cavity 10 is adaptively adjusted to offset the effect of changes in formation temperature on the pressure in the core cavity 10.

[0048] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A pressure-maintaining coring device, comprising an outer cylinder (1), a drill bit (2) mounted at the end of the outer cylinder (1), an inner cylinder (3) mounted inside the outer cylinder (1), and a differential joint (4), characterized in that: The inner tube (3) is provided with a high-pressure gas chamber (6), a fixed plug (7), a compensation chamber (8), a floating piston (9), a core chamber (10), a ball valve (11) and a sealing liquid plug (12) in sequence in the direction of the drill bit (2); the fixed plug (7) is fixed in the inner tube (3); a through hole (71) is provided on the fixed plug (7); a compensation gas valve (72) is installed on the through hole (71); a driving chamber (73) is also provided inside the fixed plug (7); a straight hole (74) is provided on the side wall of the driving chamber (73); the straight hole (74) is connected to the compensation chamber (8); a baffle (13) is installed inside the straight hole (74); and a driving assembly (5) is installed on the side wall of the driving chamber (73); The driving assembly (5) is used to drive the baffle (13) to move along the straight hole (74), and the driving assembly (5) comprises a temperature detector (51) and a transmission device (52), wherein the temperature detector (51) is used to detect the temperature of the outer wall of the inner tube (3), and the transmission device (52) is drivingly connected between the temperature detector (51) and the baffle (13); After the core is collected, the compensation gas valve (72) operates to discharge the gas in the high-pressure gas chamber (6) into the compensation chamber (8) through the through hole (71), and push the floating piston (9) to move, thereby adjusting the pressure in the core chamber (10) to a rated value. When the core is taken out, the entire inner tube (3) moves upward, and the temperature detector (51) detects the formation temperature when the inner tube (3) moves upward, and forces the transmission device (52) to operate. When the transmission device (52) operates, it drives the baffle plate (13) to move along the straight hole (74). When the baffle plate (13) moves, the gas pressure in the compensation chamber (8) is adjusted, thereby adjusting the pressure in the core chamber (10).

2. A pressure-maintaining coring device according to claim 1, characterized in that: The temperature detector (51) comprises a hollow cylinder (511), wherein the hollow cylinder (511) is fixedly embedded in the inner wall of the driving chamber (73), one end of the hollow cylinder (511) extends to the outer wall of the inner cylinder (3) and is fixedly provided with a temperature-sensitive metal cover (512), a vertical piston (513) is provided inside the hollow cylinder (511), a temperature-sensitive solution (514) is injected between the vertical piston (513) and the temperature-sensitive metal cover (512), a plug rod (515) is fixedly connected to the vertical piston (513), one end of the plug rod (515) passes through the end of the hollow cylinder (511) and extends to the inside of the driving chamber (73), and one end of the plug rod (515) away from the vertical piston (513) is fixedly connected to a main pin rod (516).

3. A pressure-maintaining coring device according to claim 2, characterized in that: A return spring (517) is sleeved on the outside of the insertion rod (515), and the return spring (517) is located inside the hollow cylinder (511). Two ends of the return spring (517) are respectively fixedly connected to the vertical piston (513) and the inner wall of the hollow cylinder (511).

4. A pressure-maintaining coring device according to claim 2, characterized in that: Both ends of the straight hole (74) are fixedly connected with mounting rods (14); the baffle plate (13) is slidably installed in the straight hole (74); the connection between the edge of the baffle plate (13) and the inner wall of the straight hole (74) is sealed; a transmission screw (15) is provided inside the straight hole (74); the transmission screw (15) passes through the baffle plate (13) and is threadedly connected to the baffle plate (13); both ends of the transmission screw (15) are rotatably connected to the two mounting rods (14) respectively; one end of the transmission screw (15) extends into the driving cavity (73) and is fixedly connected with a transmission gear (16).

5. A pressure-maintaining coring device according to claim 4, characterized in that: The transmission device (52) comprises a longitudinal rotating shaft (521) and a vertical slide rail (522), wherein the vertical slide rail (522) is fixed inside the driving cavity (73), a transmission rack (523) is slidably connected to the vertical slide rail (522), the transmission rack (523) is meshed with the transmission gear (16), and a secondary pin rod (524) is fixedly connected to the side wall of the transmission rack (523), and the secondary pin rod (524) is parallel to the main pin rod (516).

6. A pressure-maintaining coring device according to claim 5, characterized in that: Both ends of the longitudinal rotating shaft (521) are fixed to the inner wall of the driving cavity (73); a lever (525) is rotatably connected to the longitudinal rotating shaft (521); a strip-shaped hole (526) is provided on the surface of the lever (525); and the main pin rod (516) and the auxiliary pin rod (524) are both inserted into the strip-shaped hole (526).

7. The pressure-maintaining coring device according to claim 1, characterized in that: A gas recovery assembly (17) is installed on the baffle (13), and the gas recovery assembly (17) is used to recover the gas in the compensation cabin (8) to the inside of the high-pressure gas chamber (6). The gas recovery assembly (17) comprises a through hole (171) arranged on the baffle (13) and a first one-way valve (172) installed in the through hole (171).

8. A pressure-maintaining coring device according to claim 7, characterized in that: The gas recovery component (17) also includes a piston cylinder (173) fixed to the side wall of the baffle (13), the piston cylinder (173) is arranged on the side of the baffle (13) close to the drive chamber (73) and corresponds to the position of the through hole (171), and a hose (174) is fixedly connected to the side wall of the piston cylinder (173), one end of the hose (174) is connected to the through hole (71), and a second one-way valve (175) is installed at the connection between the hose (174) and the piston cylinder (173).

9. A pressure-maintaining coring device according to claim 8, characterized in that: The outer wall of the piston cylinder (173) is fixedly connected with a driving motor (176), and the output shaft of the driving motor (176) is fixed with a first bevel gear (177). The end of the piston cylinder (173) is provided with a base shaft (178), and the base shaft (178) is installed on the end surface of the piston cylinder (173) through a bearing seat (179). A second bevel gear (180) is fixed to one end of the base shaft (178), and the second bevel gear (180) is meshed with the first bevel gear (177). A rotating disk (181) is fixed to the other end of the base shaft (178), and a push rod (182) is rotatably connected to the surface of the rotating disk (181) near the edge. The other end of the push rod (182) is hinged with a driving piston (183), and the driving piston (183) is inserted into the piston cylinder (173).

10. A coring method for resource exploration sampling, characterized in that: The coring method for resource exploration and sampling uses a pressure-maintaining coring device as described in any one of claims 1-9.

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