Automatic closed type rock core anti-falling device, coring drilling tool and well drilling coring method

Abstract

The invention provides an automatic closed type rock core anti-falling device, a coring drilling tool and a well drilling coring method.The anti-falling device comprises a rock core anti-falling barrel, a baffle and a bearing seat, and the bearing seat is arranged on the inner wall of the lower end of the rock core anti-falling barrel; a baffle plate is arranged in the bearing seat and covers the through hole of the bearing seat; the baffle rotates to close or open the channel of the rock core anti-falling cylinder, and a drilling fluid pressure balance hole is formed in the baffle. The coring drilling tool comprises the automatic closed type rock core anti-falling device. The coring drilling tool is used in the well drilling and coring method. The rock core anti-falling device can solve the problem that the rock core falls into a well, the coring drilling tool is firm and reliable, and the coring method is high in success rate.

Description

Technical Field

[0001] The present invention relates to the technical field of oil drilling, and specifically, to an automatic closed core anti-falling device, a core barrel, and a drilling coring method. Background Art

[0002] A core catcher is an important component of a drilling coring tool. Its function is to clamp and cut the core, and support the core column during tripping, so as to bring the core to the ground intact for research and analysis. However, in actual coring operations, due to the fragmentation of the formation rock taken and the poor columnar formation of the core, the core catcher often fails to effectively "seal the door". As a result, the core in the inner barrel of the coring tool slips and falls into the well during tripping. When tripping in the open hole section after coring and various downhole complications need to be handled, the longitudinal shock force generated causes some or all of the core in the inner barrel to gradually slide out of the inner barrel and fall into the well from time to time. Extremely important geological data is lost, causing serious losses to the reservoir productivity evaluation. Therefore, an attempt is made to assemble a double core catcher at the lower end of the inner barrel of the coring tool to play a double-insurance supporting role for the core. However, in actual applications, the double core catcher can only effectively play a supporting role under the specific premise that one of the core catchers fails when the rock has good columnar formation, the core diameter meets the standard, and there are no complications during tripping.

[0003] With the country's increasing efforts in oil and gas development, the deployment of ultra-deep wells, highly deviated wells, horizontal wells, and tight oil and gas wells has increased year by year, and the number of coring wells has increased. Due to the development of pores and fractures in the reservoir rock, the rock is fragmented, and the columnar formation of the drilled core is poor, with many large and small blocky fragmented cores. Even with double core catchers for coring, the core is still likely to fall into the well from the inner hole of the core catcher. When coring in highly deviated wells and horizontal wells, the coring tool is approximately horizontal at the bottom of the well, and the fragmented core loses the gravity of the upper core and is not easy to accumulate in the inner barrel. During tripping, as the well inclination decreases, the fragmented core gradually slides out of the inner barrel and falls into the well; for deep wells and ultra-deep wells, the performance of the drilling fluid is difficult to maintain due to factors such as well temperature and acid gas pollution, resulting in an increased incidence of sticking during tripping in the open hole section. During the process of moving the drill string up and down to handle early sticking, it is easy to cause the shock of the downhole shock absorber. Frequent shocks cause the core and the core catcher to be simultaneously affected by the longitudinal shock force, resulting in the core gradually sliding out of the inner barrel and falling into the well, and geological data is lost; in the past two years, the new screw coring technology has effectively solved the problem of low coring speed for shale and sandstone in tight oil and gas wells. However, during the circulation process after screw coring, due to the dual influence of strong vibration and high rotation speed of the screw on the core and the core catcher, the risk of the core gradually sliding out of the inner barrel and falling into the well is relatively high. Therefore, the present application provides an efficient core anti-falling device, which overcomes the problem of the core being easily dropped into the well in complex downhole conditions.

[0004] The Chinese patent with the publication number "CN110273659B" and the name "A self-priming confining pressure protection coring inner barrel and application method" discloses a self-priming confining pressure protection coring inner barrel. An elastic liner is provided in the coring inner barrel. During the hoisting process, the elastic liner always wraps the core and can prevent the core from falling during the hoisting process. Although the effect of preventing the core from falling can be achieved, the structure of this application is simpler and the operating principle is different. During the extraction process, no air pressure is required, and the effect of preventing the core from falling can also be achieved.

[0005] The patent with the publication number "CN206920150U" and the name "Elastic reset leaf-type coring mechanism" provides a coring mechanism. A valve seat is provided on the inner wall of the coring mechanism. The valve seat includes a plurality of leaf components. The leaf components are fixed in the valve seat. When the core moves upward and leaves the valve seat, the leaf components automatically reset to close the valve seat, achieving the effect of preventing the core from falling. Different from this application, the number of baffles in this application is less than the number of leaf components of this patent, the closing area is large, there is no gap, and the closing effect is better. Summary of the Invention

[0006] The object of the present invention is to solve at least one of the above deficiencies existing in the prior art. For example, one object of the present invention is to provide a core anti-drop device capable of automatic closing. Another object of the present invention is to provide a coring tool with an automatic closing function. Another object of the present invention is to provide an efficient and high-completion-rate drilling coring method.

[0007] To achieve the above object, on the one hand, the present invention provides an automatic closing type core anti-drop device. The anti-drop device may include a core anti-drop barrel, a baffle, and a supporting seat. Among them, a supporting seat is provided on the inner wall at the lower end of the core anti-drop barrel; a baffle is provided on the supporting seat, and the baffle covers the through hole of the supporting seat; the baffle rotates to close or open the channel of the core anti-drop barrel, and a drilling fluid pressure balance hole is provided on the baffle.

[0008] According to one or more exemplary embodiments of one aspect of the present invention, one end of the baffle may be hinged to the supporting seat through a pin shaft opening and closing assembly, and the other end is in contact with the supporting seat. The pin shaft opening and closing assembly may include a baffle fixing seat, a pin shaft, a pin shaft sleeve, and a torsion reset spring. Among them, the baffle fixing seats are spaced apart on the inner wall of the supporting seat; the pin shaft sleeve and the torsion reset spring are arranged at the hinged end of the baffle. The pin shaft passes through the baffle fixing seat, the pin shaft sleeve, and the torsion reset spring to connect the baffle with the baffle fixing seat.

[0009] According to one or more exemplary embodiments of one aspect of the present invention, the rotation direction of the baffle may be towards the upper end of the core anti-drop barrel, and the rotation angle of the baffle may be 90°.

[0010] According to one or more exemplary embodiments of one aspect of the present invention, a baffle opening working position may be provided in the inner wall of the core anti-falling cylinder above the supporting seat. When the baffle is forced to be pushed open, the baffle rotates and clings to the baffle opening working position.

[0011] According to one or more exemplary embodiments of one aspect of the present invention, positioning grooves may be provided on the inner wall of the core anti-falling cylinder at the corresponding position of the supporting seat, and positioning pins matching the number of the positioning grooves may be provided on the supporting seat, and the positioning pins are arranged in the positioning grooves.

[0012] According to one or more exemplary embodiments of one aspect of the present invention, a snap ring groove may be provided on the inner wall of the core anti-falling cylinder below the supporting seat, and a snap ring is arranged in the snap ring groove, and the snap ring fixes the supporting seat and the retaining ring in the core anti-falling cylinder.

[0013] According to one or more exemplary embodiments of one aspect of the present invention, a snap ring installation and removal opening may be provided at the lower end port of the core anti-falling device for facilitating the removal of the snap ring.

[0014] According to one or more exemplary embodiments of one aspect of the present invention, connecting threads may be provided on the inner wall at the upper end of the core anti-falling cylinder for facilitating connection with an upstream tool.

[0015] On the other hand, the present invention provides an automatic closed coring drill. The coring drill may include a coring inner barrel, a reducing sleeve, core claws and the automatic closed core anti-falling device as described above. Among them, the reducing sleeve is arranged at the lower end of the coring inner barrel, the core claws are arranged inside the reducing sleeve, and the automatic closed core anti-falling device is arranged at the lower end of the reducing sleeve.

[0016] On yet another aspect, the present invention provides a drilling coring method. The method may be implemented by using the automatic closed coring drill as described above, and the coring method may include the following steps: coring drilling, the drilled core gradually pushes open the baffle, the baffle rotates to open the channel of the core anti-falling cylinder, and the core enters the coring inner barrel through the reducing sleeve equipped with core claws after passing through the core anti-falling cylinder to store the core; after the coring drilling is completed, the drill is lifted to cut the core, the core breaks from the core claws, the core at the lower end of the core claws remains at the bottom of the well, the baffle loses the constraint of the core and resets to close the channel of the core anti-falling cylinder, and the core is fixed in the core anti-falling cylinder to prevent the core from falling into the well.

[0017] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0018] (1) The anti-falling device provided by the present invention is provided with a baffle that can automatically open and close, solves the problem of the core falling into the well, and ensures the integrity of geological data;

[0019] (2) The coring tool provided by the present invention can overcome external influences and firmly control the core within the inner barrel. Even when the core catcher fails, the rock breaks, the screw coring is completed in a cycle, or complex downhole conditions require high-intensity and large-scale treatment during the process of pulling out the drill, a comprehensive core sample can still be obtained, which is more firm and reliable.

[0020] (3) The coring method provided by the present invention can automatically seal and protect the core without adding extra steps, which is more efficient and faster on the original basis. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Through the following description in conjunction with the drawings and exemplary embodiments, the above and other objects and / or features of the present invention will become clearer, where:

[0022] Figure 1 Shows a structural cross-sectional view of an automatic closed-type core anti-drop device according to an exemplary embodiment of the present invention;

[0023] Figure 2 Shows a front view of an automatic closed-type core anti-drop device according to an exemplary embodiment of the present invention;

[0024] Figure 3 Shows a schematic structural diagram of the connection between a baffle and a supporting seat according to an exemplary embodiment of the present invention;

[0025] Figure 4a Shows a schematic structural diagram of a pin shaft opening and closing assembly component according to an exemplary embodiment of the present invention;

[0026] Figure 4b Shows Figure 4a A schematic combined structure diagram of the pin shaft opening and closing assembly;

[0027] Figure 5 Shows a schematic diagram of a retaining ring structure according to an exemplary embodiment of the present invention.

[0028] DESCRIPTION OF THE REFERENCE NUMERALS:

[0029] 1 - Core anti-drop cylinder, 11 - Baffle opening working position, 12 - Retaining ring groove, 13 - Positioning groove, 14 - Retaining ring installation and extraction opening, 15 - Connecting thread, 21 - Supporting seat, 22 - Baffle, 23 - Pin shaft opening and closing assembly, 231 - Pin shaft, 232 - Torsion reset spring, 233 - Pin shaft sleeve, 234 - Baffle fixing seat, 24 - Positioning pin, 25 - Drilling fluid pressure balance hole, 3 - Retaining ring. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0030] Hereinafter, an automatic closed-type core anti-drop device, a coring tool, and a drilling coring method of the present invention will be described in detail in conjunction with the drawings and exemplary embodiments.

[0031] It should be noted that "first", "second", "third", etc. are only for convenience of description and differentiation, and should not be construed as indicating or implying relative importance. "Upper", "lower", "inner", "outer", etc. are only for convenience of description and to form relative orientation or positional relationships, and do not indicate or imply that the components referred to must have such specific orientations or positions.

[0032] First Exemplary Embodiment

[0033] This exemplary embodiment provides an automatic closed - type core anti - dropping device.

[0034] Figure 1 Shows a structural cross - sectional view of an automatic closed - type core anti - dropping device according to an exemplary embodiment of the present invention; Figure 2 Shows a front view of an automatic closed - type core anti - dropping device according to an exemplary embodiment of the present invention; Figure 3 Shows a schematic structural view of the connection between a baffle plate and a supporting seat according to an exemplary embodiment of the present invention; Figure 4a Shows a schematic structural view of a pin shaft opening and closing assembly component according to an exemplary embodiment of the present invention; Figure 4b Shows Figure 4a a schematic combined structure view of the pin shaft opening and closing assembly; Figure 5 Shows a schematic structural view of a snap ring according to an exemplary embodiment of the present invention. The following will describe the automatic closed - type core anti - dropping device of this exemplary embodiment in conjunction with Figures 1 to 5 The direction from bottom to top described in the specification is the direction from left to right in Figure 1 .

[0035] As Figure 1 shown, the automatic closed - type core anti - dropping device mainly includes a core anti - dropping cylinder 1, a baffle plate 22 and a supporting seat 21. The supporting seat 21 is arranged on the inner wall of the lower end of the core anti - dropping cylinder 1. The baffle plate 22 is installed on the supporting seat, which is convenient for taking out and assembling the baffle plate, and for inspecting and replacing the corresponding components. If the baffle plate is directly installed on the inner wall of the core anti - dropping cylinder, due to space limitations, it is not convenient to repair or replace the components. The baffle plate is rotatable to open or close the core anti - dropping cylinder. As Figure 3 shown, a plurality of drilling fluid pressure balance holes 25 can be evenly arranged on the baffle plate 22. During the coring process, the drilling fluid pressure at the lower end of the baffle plate is greater than the drilling fluid pressure above the baffle plate, and the closing of the baffle plate may be blocked. The setting of the drilling fluid pressure balance holes is beneficial to balancing the drilling fluid pressure at the upper and lower ends of the baffle plate and promoting the closing of the baffle plate. When the coring tool exits the well, the drilling fluid in the inner cylinder can also be released in time through the drilling fluid pressure balance holes.

[0036] Furthermore, as Figure 3As shown, two baffles 22 can be oppositely arranged on the supporting base 21. The baffles can be those with a large force-bearing area and high strength. A single baffle has a large force-bearing area, high strength, and a simple structure. Each baffle is provided with a plurality of drilling fluid pressure balance holes for pressure balance above and below the baffle, improving the reliability of automatic closing. Moreover, when the core is cut and lifted from the bottom of the well by the coring tool, the baffle resets and closes. The corresponding ends of the baffle connected to the supporting base all have force points, which can bear a large weight and are not easily deformed. And at present, petroleum drilling coring mainly focuses on deep wells and ultra-deep wells with a depth of 5000 - 10000 meters. Long barrel coring is often required. The core has a large weight, and during the process of pulling out the drill string after coring, it often gets stuck. To release the blockage, it is necessary to vigorously move the drill string up and down or use a shocker to shock. In these two working conditions, the longitudinal force formed on the inner barrel of the coring tool is extremely large, that is to say, the downward force on the core increases. Therefore, preferably, the baffles for preventing the core from falling out of the barrel are arranged in two pieces and both ends of the baffle have force points, which are sufficient to bear the gravity of the upper core. If multiple baffles are set, the strength of a single baffle will decrease. When a certain baffle is deformed, under the action of gravity, the other baffles will also be deformed, causing the core to fall into the well.

[0037] Furthermore, as Figure 3 shown, one end of the baffle can be hinged to the supporting base by a pin opening and closing assembly 23. As Figure 4a shown, the pin opening and closing assembly can include a pin 231, a pin sleeve 233, a baffle fixing seat 234, and a torsion return spring 232. Among them, the baffle fixing seat 234 can include fixing seat ears spaced on the inner wall of the supporting base. The pin sleeve 233 is arranged at the edge of the baffle 22. The torsion return spring 232 can be fixed by the pin 231 at the hinge of the baffle 22 and the supporting base 21. For example, as Figure 4b shown, a pin sleeve 233 can be respectively arranged at both ends of the edge of each baffle 22 to fix the baffle 22 and limit the opposite landing points of the baffle 22 when it is closed. The pin sleeve 233 and the baffle 22 can be integrally arranged. After assembly, the torsion return spring 232 can be arranged inside the pin sleeve 233. When coring is completed, the torsion return spring forces the baffle to automatically flip and close the core anti-falling barrel by its own elasticity. The pin 231 passes through the baffle fixing seat (not shown in the figure), the pin sleeve 233, and the torsion return spring 232 in sequence to realize the fixation between the supporting base and the baffle.

[0038] In this exemplary embodiment, as Figure 1 shown, a baffle opening working position 11 can be opened on the inner wall of the core anti-falling barrel 1 at the upper end of the supporting base 21. When the baffle 22 is forced upward, restricted by the pin sleeve, the baffle rotates towards the upper end direction of the core anti-falling barrel, that is Figure 1 in the right direction, and the rotation angle can be 90°. The baffle can be closely attached to the baffle opening working position.

[0039] In this exemplary embodiment, as Figure 3 shown, a positioning pin 24 may be provided on the outer side of the supporting seat. As Figure 1 shown, a positioning groove 13 may be formed on the inner wall of the core anti-drop cylinder. The positioning pin is fixed in the positioning groove 13 to restrict the rotation of the baffle and the support seat in the core anti-drop cylinder, preventing the baffle assembly from being misaligned in the core anti-drop cylinder during core drilling and tripping operations. Here, one positioning pin can be provided on the outer side of the supporting seat to achieve circumferential fixation and prevent the supporting seat from rotating. Similarly, a positioning groove can also be provided on the inner wall of the core anti-drop cylinder in the corresponding direction.

[0040] In this exemplary embodiment, as Figure 1 shown, a snap ring groove 12 may also be formed at the lower end of the inner wall of the core anti-drop cylinder 1, for example, on the inner wall of the core anti-drop cylinder 1 at the lower end of the supporting seat 21. A snap ring 3 as Figure 5 shown can be placed in the snap ring groove 12 to prevent the baffle and the supporting seat from falling into the well.

[0041] Furthermore, as Figure 2 shown, a snap ring installation and removal opening 14 for removing or installing the snap ring may also be formed at the lower end of the core anti-drop cylinder 1 of the snap ring groove. After removing the snap ring, the baffle can be taken out in time. Check the damage condition of the baffle assembly and perform repair or replacement. For example, the snap ring can be clamped by a snap ring extraction pliers at the snap ring installation and removal opening 14 and then taken out from the lower end of the core anti-drop cylinder 1. The baffle in the core anti-drop cylinder 1 loses the longitudinal fixation of the snap ring, and the baffle can be taken out from the lower port of the core anti-drop cylinder 1 for repair and replacement.

[0042] In this exemplary embodiment, as Figure 1 shown, a connection thread 15 for connecting with an upstream tool may also be provided at the upper end port of the core anti-drop cylinder 1. Here, the upstream tool may include a core drilling tool.

[0043] Second Exemplary Embodiment

[0044] This exemplary embodiment provides an automatic closed core drilling tool.

[0045] In this exemplary embodiment, the automatic closed core drilling tool mainly includes a core inner barrel, a reducing sleeve, core claws and the automatic closed core anti-drop device as described in the above first exemplary embodiment. The reducing sleeve is arranged at the lower end of the core inner barrel, the core claws are assembled inside the reducing sleeve, and the automatic closed core anti-drop device is arranged at the lower end of the reducing sleeve. The automatic closed core anti-drop device can be threadedly connected with the reducing sleeve.

[0046] In this exemplary embodiment, the core barrel can be suspended on the outer barrel of the coring tool by bearings. The lower end of the inner barrel is threadedly connected to a reduced-diameter sleeve equipped with core claws, and the lower end of the reduced-diameter sleeve is threadedly connected to a core anti-falling barrel. The drilled core first passes through the core anti-falling barrel. After pushing open the baffle, the core gradually passes through the reduced-diameter sleeve equipped with core claws and enters the inner barrel of the coring tool for storing the core upward.

[0047] The third exemplary embodiment

[0048] This exemplary embodiment provides an automatic closed drilling coring method.

[0049] This exemplary embodiment is implemented using the automatic closed drilling coring tool as described in the second exemplary embodiment, and the coring method mainly includes the following steps:

[0050] S1: During the coring process, the core continuously enters the core anti-falling barrel. At this time, the core pushes open the baffle, and the core passes through the channel of the core anti-falling barrel.

[0051] S2: The core claws grab the core and cut the core. The core passes through the reduced-diameter sleeve and enters the inner coring barrel. After the coring tool pulls out the drill string to cut the core and leaves the bottom of the well, the baffle loses the core limit constraint and automatically resets to close the core anti-falling barrel, preventing the core from sliding down into the well.

[0052] In this exemplary embodiment, during the drill string pulling process, if the core claws cannot effectively lock the core and cause the core to slide down, whether the core has good columnarity or is broken, it is supported by the baffle at this time, and the falling well channel is completely closed, realizing that the core is firmly fixed in the inner barrel and completely solving the problem of the core falling into the well.

[0053] In summary, the advantages of the present invention may include at least one of the following:

[0054] (1) The anti-falling device provided by the present invention can completely solve the problem of the core being easily dropped into the well in various downhole complex links such as rock fragmentation, core claw failure, screw coring completion cycle, and drill string pulling after coring completion, ensuring the integrity of the coring operation result;

[0055] (2) The anti-falling device provided by the present invention has a simple structure and does not affect the structure of the coring tool during installation, the operation of tripping in and out, circulation, and coring drilling. On the existing basis, it further improves the coring construction efficiency and shortens the drilling cycle;

[0056] (3) The coring tool provided by the present invention overcomes the problem of the core slipping out caused by strong vibration and high rotation speed in the new screw coring process, reducing the risk of the core falling into the well;

[0057] (4) When accidents such as stuck pipe occur downhole, the coring method provided by the present invention no longer needs to consider the risk of the core falling into the well, so that the selection of treatment methods and scopes is more extensive, thereby improving the flexibility, speed and economy of complex treatment, and effectively reducing the time for dealing with complex faults;

[0058] (5) The coring tool provided by the present invention can achieve coring in deep wells or ultra-deep wells, has a wide application range and a high coring success rate.

[0059] Although the automatic closed core anti-falling device, coring drill and drilling coring method of the present invention have been described above by combining exemplary embodiments, those skilled in the art should clearly understand that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. An automatic closed - type core anti - dropping device, characterized in that, the anti - dropping device includes a core anti - dropping cylinder, a baffle plate and a supporting seat, wherein, a supporting seat is arranged on the inner wall of the lower end of the core anti - dropping cylinder; a baffle plate is arranged on the supporting seat, and the baffle plate covers the through - hole of the supporting seat; the baffle plate rotates to close or open the channel of the core anti - dropping cylinder, and a drilling fluid pressure balance hole is opened on the baffle plate.

2. The automatic closed - type core anti - dropping device according to claim 1, characterized in that, one end of the baffle plate is hinged to the supporting seat through a pin shaft opening - closing assembly, and the other end is in contact with the supporting seat. The pin shaft opening - closing assembly includes a baffle plate fixing seat, a pin shaft, a pin shaft sleeve and a torsion return spring, wherein, the baffle plate fixing seats are arranged at intervals on the inner wall of the supporting seat; the pin shaft sleeve and the torsion return spring are arranged at the hinged end of the baffle plate; the pin shaft passes through the baffle plate fixing seat, the pin shaft sleeve and the torsion return spring to connect the baffle plate with the baffle plate fixing seat.

3. The automatic closed - type core anti - dropping device according to claim 2, characterized in that, the rotation direction of the baffle plate is to rotate upward to the upper end of the core anti - dropping cylinder, and the rotation angle of the baffle plate is 90°.

4. The automatic closed - type core anti - dropping device according to claim 1, characterized in that, a baffle plate opening working position is arranged in the inner wall of the core anti - dropping cylinder above the supporting seat. When the baffle plate is forced to be pushed open, the baffle plate rotates and clings to the baffle plate opening working position.

5. The automatic closed - type core anti - dropping device according to claim 1, characterized in that, positioning grooves are opened on the inner wall of the core anti - dropping cylinder at the corresponding position of the supporting seat, and positioning pins matching the number of the positioning grooves are arranged on the supporting seat, and the positioning pins are arranged in the positioning grooves.

6. The automatic closed - type core anti - dropping device according to claim 1, characterized in that, a snap - ring groove is opened on the inner wall of the core anti - dropping cylinder below the supporting seat, and a snap - ring is arranged in the snap - ring groove. The snap - ring fixes the supporting seat and the retaining ring in the core anti - dropping cylinder.

7. The automatic closed - type core anti - dropping device according to claim 6, characterized in that, a snap - ring installation and removal port is opened at the lower end port of the core anti - dropping device for taking out the snap - ring.

8. The automatic closed - type core anti - dropping device according to claim 1, characterized in that, connecting threads are arranged on the inner wall of the upper end of the core anti - dropping cylinder for connecting with upstream tools.

9. An automatic closed - type core - drilling tool, characterized in that, the core - drilling tool includes a core inner barrel, a reducing sleeve, core claws and the automatic closed - type core anti - dropping device according to any one of claims 1 - 8. The reducing sleeve is arranged at the lower end of the core inner barrel, the core claws are arranged inside the reducing sleeve, and the automatic closed - type core anti - dropping device is arranged at the lower end of the reducing sleeve.

10. A drilling coring method, characterized in that, the method is realized by using the automatic closed - type core - drilling tool according to claim 9, and the coring method includes the following steps: Coring drilling, the drilled core gradually pushes open the baffle plate, the baffle plate rotates to open the channel of the core anti - dropping cylinder, and the core enters the core inner barrel through the reducing sleeve equipped with core claws after passing through the core anti - dropping cylinder to store the core; After coring drilling is completed, the drill string is lifted to cut the core. The core breaks at the core catcher, and the core below the lower end of the core catcher remains at the bottom of the well. The baffle loses the core constraint and resets to close the passage of the core anti-drop barrel. The core is fixed in the core anti-drop barrel to prevent the core from falling into the well.

Images