Anti-blocking and anti-settling multidirectional pressure-maintaining coring device and using method thereof

Abstract

The invention relates to an anti-blocking and anti-sinking multidirectional pressure-maintaining coring device and a using method thereof.The anti-blocking and anti-sinking multidirectional pressure-maintaining coring device comprises an outer barrel, a center rod, a core barrel, a flap valve, a first dynamic sealing device and a second dynamic sealing device, the core barrel is located in the outer barrel, the lower end of the center rod is connected with the core barrel, and the flap valve comprises a valve seat and a valve clack; the first dynamic sealing device and the second dynamic sealing device are coaxially arranged in the outer cylinder and are respectively positioned above and below the flap valve; each of the first dynamic sealing device and the second dynamic sealing device comprises a barrel-shaped base body, a sealing ring is arranged on the inner wall of each barrel-shaped base body, and the barrel-shaped base bodies are arranged outside the core barrel in a sleeving manner; spiral grooves are formed in the outer wall of the center rod. According to the dynamic sealing device, external drilling fluid, rock debris and other impurities can be prevented from entering the pressure maintaining cabin to pollute the sealing environment of the pressure maintaining controller; the center rod can rotate under the action of the drilling fluid, drive the core barrel to rotate and drive the circumferential deposition drilling fluid to rotate, and blockage of internal parts caused by deposition of the drilling fluid can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of pressure-maintaining coring, and in particular to an anti-blocking and anti-sinking multi-directional pressure-maintaining coring device and a use method thereof. Background Art

[0002] Traditional pressure-maintaining coring technology can only realize vertical pressure-maintaining coring technology. This research and development team proposed a multi-directional pressure-maintaining coring technology based on magnetic control, which realized the anti-gravity self-driving of the flap valve and realized the initial self-sealing of magnetic control, such as the simple magnetic-triggered multi-directional pressure-maintaining coring device and rock sample extraction method disclosed in the Chinese patent document with publication number CN113958279A. Multi-directional pressure-maintaining coring technology can realize pressure-maintaining coring tests at multiple angles in a single borehole formation, increasing the efficiency of deep in-situ fidelity exploration and reducing economic costs. However, when coring in multiple directions such as horizontal and inclined directions, there is still a risk of pressure-maintaining failure due to the precipitation of cuttings and drilling fluid on the sealing surface of the flap valve and inside the pressure-maintaining chamber.

[0003] In the complex environment of deep reservoirs, the pressure-maintaining system must not only cope with high temperature, high pressure and corrosive fluids, but must also effectively prevent mud and solid particles from entering the system to avoid seal failure. Mud is suspended in the downhole high-pressure fluid and can easily enter the key sealing parts of the pressure-maintaining system through the fluid channel, causing wear and blockage of the sealing surface, and even causing system failure; larger solid particles in the reservoir (such as rock cuttings) may accumulate in the sealing area, hindering the normal operation of the system. In addition, during multi-directional coring, especially horizontal coring, the mud drilling fluid settles inside the coring device and cannot be discharged, resulting in the inability to trigger the pressure-maintaining action. The problem of pressure-maintaining failure is also worth noting. Summary of the invention

[0004] In order to solve the above technical problems, the present invention provides an anti-blocking and anti-sinking multi-directional pressure-maintaining coring device and a method of using the same.

[0005] The present invention is achieved through the following technical solutions:

[0006] A multi-directional pressure-maintaining coring device for preventing blockage and sinking, comprising an outer cylinder, a center rod, a core barrel, a flap valve, a first dynamic sealing device and a second dynamic sealing device, the core barrel is located in the outer cylinder, the lower end of the center rod is connected to the core barrel, the flap valve comprises a valve seat and a valve disc, the valve seat is coaxially mounted in the outer cylinder, one end of the valve disc is movably connected to the upper end of the valve seat; when the valve disc is opened, the core barrel can pass through the valve seat; the first dynamic sealing device and the second dynamic sealing device are coaxially mounted in the outer cylinder, the first dynamic sealing device is located above the flap valve, and the second dynamic sealing device is located below the flap valve; the first dynamic sealing device and the second dynamic sealing device both comprise a cylindrical base, the inner wall of the cylindrical base is provided with a sealing ring, the cylindrical base is sleeved outside the core barrel and is in sealing contact with the outer wall of the core barrel through the sealing ring on the inner wall.

[0007] Particularly, a sealing ring is arranged on the outer wall of the cylindrical base of the first dynamic sealing device.

[0008] Optionally, the outer tube includes a first section, a second section and a third section, the upper end of the first section is threadedly connected to the lower end of the second section, the upper end of the second section is threadedly connected to the lower end of the third section, and the flap valve, the first dynamic sealing device and the second dynamic sealing device are all installed in the second section;

[0009] The upper end of the cylindrical base of the second dynamic sealing device abuts against the lower end of the valve seat, and the lower end of the cylindrical base of the second dynamic sealing device abuts against the upper end surface of the first section, thereby realizing axial fixation of the cylindrical base of the second dynamic sealing device; the upper end of the cylindrical base of the first dynamic sealing device abuts against the lower end surface of the third section, and the lower end of the cylindrical base of the first dynamic sealing device abuts against the inner step of the second section, thereby realizing axial fixation of the cylindrical base of the first dynamic sealing device.

[0010] Optionally, the inner wall of the cylindrical base has an inner step that matches the sealing ring, the inner end of the sealing ring abuts against the inner step of the cylindrical base, the end face of the cylindrical base has an annular groove for installing a fixing ring, the fixing ring is installed in the annular groove and fixed to the cylindrical base by screws, the fixing ring is located at the outer end of the sealing ring, and the axial fixation of the sealing ring is achieved by the joint action of the inner step and the fixing ring.

[0011] Optionally, the core barrel includes a disc and a coaxial cylinder, the upper end of the cylinder is connected to the disc, and the lower end of the center rod is connected to the disc; the disc is provided with a plurality of drilling fluid flow holes, the lower ends of the drilling fluid flow holes are communicated with the interior of the cylinder, the first dynamic sealing device and the second dynamic sealing device are sleeved outside the cylinder, and are respectively sealed with the cylinder through their sealing rings.

[0012] Optionally, the upper end surface of the disc is grooved and equipped with two end surface sealing rings, and the drilling fluid flow channel hole is located between the two end surface sealing rings.

[0013] Optionally, a connecting hole is provided in the center of the upper end surface of the disc, the lower end of the center rod is connected to the connecting hole, and a plurality of drilling fluid flow channel holes are arranged at equal intervals in the circumferential direction around the connecting hole.

[0014] Optionally, the outer surface of the center rod has a spiral groove.

[0015] Optionally, a first magnetic component is mounted on the valve flap, and a second magnetic component that is mutually exclusive with the first magnetic component is mounted on the outer cylinder. When the valve flap is opened, the first magnetic component is directly opposite to the second magnetic component.

[0016] The present application provides a method for using a multi-directional pressure-maintaining coring device to prevent blocking and sinking, comprising the following steps: after the coring device is installed, a seal is formed between the core barrel and the first dynamic sealing device and the second dynamic sealing device, and the interior of the pressure-maintaining cabin is in a completely sealed state; in the sealed state, a protective gas is filled into the system to form a gas barrier;

[0017] When the coring device is lowered to the bottom of the target hole, the drilling fluid flows in the spiral groove on the outer surface of the center rod. When the flow rate of the drilling fluid reaches a first predetermined value, the center rod can start to rotate under the action of the drilling fluid, driving the core barrel to rotate together; when the coring operation is performed, the drilling fluid flow rate is reduced to a second predetermined value, and the center rod stops rotating;

[0018] Compared with the prior art, this application has at least the following beneficial effects:

[0019] 1. The present application sets dynamic sealing devices at both ends of the pressure-maintaining chamber, and a seal is formed between the core barrel and the first dynamic sealing device and the second dynamic sealing device to prevent drilling fluid, rock cuttings and other impurities from entering the pressure-maintaining chamber and polluting the sealing environment of the pressure-maintaining controller; when drilling and coring, the second dynamic sealing device can effectively prevent rock cuttings from entering the pressure-maintaining chamber to form precipitation or wear, and the first dynamic sealing device effectively prevents drilling fluid from flowing through the pressure-maintaining chamber and the pressure-maintaining assembly to form precipitation; and inert gas can be filled inside the pressure-maintaining chamber to form an internal pressure difference, effectively preventing mud and rock cuttings from entering the pressure-maintaining chamber under the action of hydrostatic difference;

[0020] 2. The present application provides a spiral groove on the outer surface of the center rod. The center rod can rotate under the action of the drilling fluid and drive the core barrel to rotate, and drive the circumferentially deposited drilling fluid to rotate, which can avoid the blockage of internal parts caused by the deposition of drilling fluid;

[0021] 3. The drilling fluid of the present application enters the drilling fluid flow channel from the upper end of the corer, passes through the center rod, enters the core barrel from the flow channel hole at the upper end of the core barrel, and then flows through the bottom of the hole. During this process, the drilling fluid does not contact the flap valve, which effectively prevents the drilling fluid from settling on the sealing surface of the flap valve and improves the sealing performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 It is a cross-sectional view of the anti-blocking and anti-sinking multi-directional pressure-maintaining coring device in the embodiment;

[0024] Figure 2 for Figure 1 Sectional view at CC;

[0025] Figure 3 for Figure 1 A partial enlarged view of the middle A;

[0026] Figure 4 for Figure 1 A partial enlarged view of point B in the middle;

[0027] Figure 5 for Figure 2 A partial enlarged view of point E in the middle;

[0028] Figure 6 for Figure 2 A partial enlarged view of point D in the middle;

[0029] Figure 7 for Figure 6 Cross-sectional view at FF;

[0030] Figure 8 It is a structural schematic diagram of a core barrel in an embodiment;

[0031] Fig. 9 for Figure 8 A partial enlarged view of the G in the middle;

[0032] Fig.10 is a three-dimensional diagram of the first dynamic sealing device in the embodiment;

[0033] Fig.11 is a three-dimensional diagram of the second dynamic sealing device in the embodiment;

[0034] Fig.12 2 is a cross-sectional view of the second dynamic sealing device in the embodiment. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0036] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments of the present invention can be combined with each other. It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other.

[0037] In the description of the present invention, it should be noted that the terms "upper", "lower", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the inventive product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0038] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] like Figure 1-Figure 6 As shown, the anti-blocking and anti-sinking multi-directional pressure-maintaining coring device disclosed in this embodiment includes an outer tube 1, a center rod 2, a core barrel 3, a flap valve 4, a first dynamic sealing device 5 and a second dynamic sealing device 6. The core barrel 3 is located in the outer tube 1, and the lower end of the center rod 2 is connected to the core barrel 3. The flap valve 4 includes a valve seat 41 and a valve flap 42. The valve seat 41 is coaxially installed in the outer tube 1, and a sealing ring is sealed between the outer wall of the valve seat 41 and the inner wall of the outer tube 1. One end of the valve flap 42 is movably connected to the upper end of the valve seat 41. When the valve flap 42 is opened, the core barrel 3 can pass through the valve seat 41.

[0040] The valve flap 42 is provided with a first magnetic member 43, and the outer cylinder 1 is provided with a second magnetic member 44 which is mutually exclusive with the first magnetic member 43. When the valve flap 42 is opened, the first magnetic member 43 faces the second magnetic member 44. The first magnetic member 43 and the second magnetic member 44 are permanent magnets.

[0041] like Figure 10-12 As shown, the first dynamic sealing device 5 and the second dynamic sealing device 6 both include a cylindrical base 51 , the inner wall of the cylindrical base 51 is provided with a sealing ring 52 , and the outer wall of the cylindrical base 51 of the first dynamic sealing device 5 is provided with a sealing ring 52 .

[0042] The first dynamic sealing device 5 and the second dynamic sealing device 6 are coaxially installed in the outer tube 1. The first dynamic sealing device 5 is located above the flap valve 4, and the second dynamic sealing device 6 is located below the flap valve 4. The cylindrical base 51 is sleeved outside the core tube 3 and is in sealing contact with the outer wall of the core tube 3 through the sealing ring 52 on the inner wall.

[0043] In a possible design, the inner wall of the outer cylinder 1 has an inner step 121 , and the lower end of the cylindrical base 51 of the first dynamic sealing device 5 can abut against the inner step 121 to achieve axial fixation of the cylindrical base 51 .

[0044] The outer tube 1 includes a first section 11, a second section 12 and a third section 13. The upper end of the first section 11 is threadedly connected to the lower end of the second section 12, and the upper end of the second section 12 is threadedly connected to the lower end of the third section 13. The flap valve 4, the first dynamic sealing device 5 and the second dynamic sealing device 6 are all installed in the second section 12.

[0045] In a possible design, the upper end of the cylindrical base 51 of the second dynamic sealing device 6 abuts against the lower end of the valve seat 41, and the lower end of the cylindrical base 51 of the second dynamic sealing device 6 abuts against the upper end surface of the first section 11, thereby achieving axial fixation of the cylindrical base 51 of the second dynamic sealing device 6. The upper end of the cylindrical base 51 of the first dynamic sealing device 5 abuts against the lower end surface of the third section 13, and the lower end of the cylindrical base 51 of the first dynamic sealing device 5 abuts against the inner step 121 of the second section 12, thereby achieving axial fixation of the cylindrical base 51 of the first dynamic sealing device 5.

[0046] Optional, such as Figure 10-12 As shown, the inner wall of the cylindrical base 51 has an inner step adapted to the sealing ring 52, the inner end of the sealing ring 52 abuts against the inner step of the cylindrical base 51, and the end face of the cylindrical base 51 has an annular groove for installing a fixing ring 54. The fixing ring 54 is installed in the annular groove and fixed to the cylindrical base 51 by screws 54. The fixing ring 54 is located at the outer end of the sealing ring 52, and the axial fixed installation of the sealing ring 52 is achieved by the joint action of the inner step and the fixing ring 54.

[0047] Preferably, two sealing rings 52 are installed on the cylindrical base 51 , and the sealing rings 52 are installed at both ends of the cylindrical base 51 respectively.

[0048] In one possible design, Figure 7 , 8 , Fig. 9 As shown, the core barrel 3 includes a disc 31 and a coaxial cylinder 32, the upper end of the cylinder 32 is connected to the disc 31, the lower end of the center rod 2 is connected to the disc 31, and there are multiple drilling fluid flow holes 34 on the disc 31, and the lower ends of the drilling fluid flow holes 34 are connected to the inside of the cylinder 32. Two end face sealing rings 35 are installed in the grooves on the upper end surface of the disc 31, and the drilling fluid flow hole 34 is located between the two end face sealing rings 35. The cylindrical base 51 of the first dynamic sealing device 5 and the second dynamic sealing device 6 is sleeved outside the cylinder 32, and is sealed with the cylinder 32 through the sealing ring 52 respectively. The lower end of the corer is against the flap valve 4, and the end face sealing ring 35 is used to seal the upper part of the corer to form a static seal with the top.

[0049] Optionally, a connecting hole 33 is provided at the center of the upper end surface of the disk 31 , the lower end of the center rod 2 is connected to the connecting hole 33 , and a plurality of drilling fluid flow holes 34 are arranged around the connecting hole 33 at equal intervals in the circumferential direction.

[0050] In some embodiments, the outer surface of the center rod 2 has a spiral groove 21, and the spiral groove 21 can be used as a drilling fluid flow channel. Optionally, a flexible member can be added to the spiral rod to assist in stirring the drilling fluid and prevent precipitation.

[0051] Working principle of this embodiment: In the multi-directional pressure-maintaining coring system, after the coring device is installed, the interior of the pressure-maintaining chamber is in a completely sealed state, and the specific sealing structure is as follows: a rotating dynamic seal and an axial dynamic seal are formed between the core barrel 3 and the first dynamic sealing device 5 and the second dynamic sealing device 6 to prevent external fluid and impurities from entering the pressure-maintaining chamber; a seal is formed between the first dynamic sealing device 5, the second dynamic sealing device 6 and the pressure-maintaining chamber to ensure the stability of the double-layer sealing structure.

[0052] In some embodiments, a one-way valve 7 is installed on the side wall of the outer cylinder 1, and the one-way valve 7 is located between the first dynamic sealing device 5 and the second dynamic sealing device 6; in a sealed state, protective gas is filled into the sealed space between the first dynamic sealing device 5, the second dynamic sealing device 6, the outer surface of the core cylinder 3, and the inner surface of the outer cylinder through the one-way valve 7 to form a gas barrier, further improving the protection ability of the sealing surface. It can effectively prevent drilling fluid or cuttings from entering the pressure chamber, avoiding erosion and blockage of the flap valve 4.

[0053] When the coring device is lowered to the bottom of the target hole, when the flow rate of the drilling fluid reaches the first predetermined value, the center rod 2 can start to rotate under the action of the drilling fluid, driving the core barrel 3 to rotate together. This rotational motion can effectively stir the drilling fluid to prevent the drilling fluid from settling inside the coring device, thereby avoiding the blockage of internal parts caused by the deposition of drilling fluid; when the drilling fluid flow rate drops to the second predetermined value during the coring operation, the center rod 2 stops rotating to prevent the core from being disturbed and damaged during the coring process. The efficiency of the coring operation and the integrity of the sample can be greatly improved.

[0054] The drilling fluid flow hole 34 at the upper end of the core barrel 3 can be used as a drilling fluid flow hole to prevent the drilling fluid from flowing through the flap valve 4. During the coring process, the drilling fluid flows along the following path: the drilling fluid passes through the annulus between the center rod 2 and the outer barrel 1, flows through the drilling fluid flow hole 34 at the upper end of the core barrel 3, enters the core barrel 3, and then flows to the bottom of the hole. It can ensure that the drilling fluid does not directly contact the pressure-maintaining chamber and the flap valve 4, thereby avoiding the erosion and contamination of the flap valve 4 by the drilling fluid, and the risk of drilling fluid precipitation, ensuring the long-term reliability of the equipment.

[0055] When the lower end of the core barrel 3 releases the constraint on the rotation direction of the valve disc 42, a trigger driving force is formed between the first magnetic member 43 and the second magnetic member 44, driving the valve disc 42 to rotate and close, and forming the initial self-sealing of the pressure-maintaining controller. This sealing action ensures the upper end sealing reliability of the system, prevents drilling fluid or impurities from invading the pressure-maintaining chamber from the upper end, and further ensures the sealing performance of the entire pressure-maintaining system.

[0056] The dynamic sealing device realizes rotational dynamic sealing during the whole coring process, that is, the core barrel and the dynamic sealing device can rotate, but also have a sealing effect; at the same time, it also has an axial dynamic sealing effect, and when the core barrel is lifted, it can also ensure the sealing of the core barrel when it moves axially.

[0057] This embodiment combines a variety of technical means such as dynamic sealing devices, drilling fluid flow holes, spiral center rods, and permanent magnet auxiliary seals to ensure the environmental stability of the pressure-maintaining system and the reliable operation of the multi-directional pressure-maintaining coring system in complex underground environments. It not only solves traditional problems such as erosion, backflow, and precipitation of drilling fluid and cuttings, but also improves the stability and reliability of the pressure-maintaining system in extreme environments through multi-layer protection and dynamic adjustment.

[0058] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A multi-directional pressure-maintaining coring device for preventing blockage and sinking, characterized in that: The invention comprises an outer cylinder (1), a center rod (2), a core cylinder (3), a flap valve (4), a first dynamic sealing device (5) and a second dynamic sealing device (6); the core cylinder (3) is located in the outer cylinder (1); the lower end of the center rod (2) is connected to the core cylinder (3); the flap valve (4) comprises a valve seat (41) and a valve flap (42); the valve seat (41) is coaxially mounted in the outer cylinder (1); one end of the valve flap (42) is movably connected to the upper end of the valve seat (41); when the valve flap (42) is opened, the core cylinder (3) can pass through the valve seat (41); A first dynamic sealing device (5) and a second dynamic sealing device (6) are coaxially mounted in the outer cylinder (1), the first dynamic sealing device (5) is located above the flap valve (4), and the second dynamic sealing device (6) is located below the flap valve (4); The first dynamic sealing device (5) and the second dynamic sealing device (6) both comprise a cylindrical base (51), the inner wall of which is provided with a sealing ring (52), the cylindrical base (51) being sleeved outside the core barrel (3), and the sealing ring (52) on the inner wall of the cylindrical base (51) being in sealing contact with the outer wall of the core barrel (3).

2. The anti-blocking and anti-sinking multi-directional pressure-maintaining coring device according to claim 1 is characterized in that: The outer wall of the cylindrical base (51) of the first dynamic sealing device (5) is provided with a sealing ring (52).

3. The anti-blocking and anti-sinking multi-directional pressure-maintaining coring device according to claim 1, characterized in that: The outer tube (1) comprises a first section (11), a second section (12) and a third section (13); the upper end of the first section (11) is threadedly connected to the lower end of the second section (12); the upper end of the second section (12) is threadedly connected to the lower end of the third section (13); the flap valve (4), the first dynamic sealing device (5) and the second dynamic sealing device (6) are all installed in the second section (12); The upper end of the cylindrical base (51) of the second dynamic sealing device (6) abuts against the lower end of the valve seat (41), and the lower end of the cylindrical base (51) of the second dynamic sealing device (6) abuts against the upper end surface of the first section (11), thereby achieving axial fixation of the cylindrical base (51) of the second dynamic sealing device (6); The upper end of the cylindrical base (51) of the first dynamic sealing device (5) abuts against the lower end surface of the third section (13), and the lower end of the cylindrical base (51) of the first dynamic sealing device (5) abuts against the inner step (121) of the second section (12), thereby achieving axial fixation of the cylindrical base (51) of the first dynamic sealing device (5).

4. A multi-directional pressure-maintaining coring device for preventing blockage and sinking according to any one of claims 1 to 3, characterized in that: The inner wall of the cylindrical base (51) is provided with an inner step adapted to the sealing ring (52); the inner end of the sealing ring (52) abuts against the inner step of the cylindrical base (51); the end surface of the cylindrical base (51) is provided with an annular groove for mounting a fixing ring (54); the fixing ring (54) is mounted in the annular groove and fixed to the cylindrical base (51) by means of screws (54); the fixing ring (54) is located at the outer end of the sealing ring (52); and the sealing ring (52) is axially fixed by the combined action of the inner step and the fixing ring (54).

5. The anti-blocking and anti-sinking multi-directional pressure-maintaining coring device according to claim 1, characterized in that: The core barrel (3) comprises a disc (31) and a coaxial cylinder (32), the upper end of the cylinder (32) is connected to the disc (31), and the lower end of the center rod (2) is connected to the disc (31); The disc (31) is provided with a plurality of drilling fluid flow holes (34), the lower ends of the drilling fluid flow holes (34) are communicated with the interior of the cylinder (32), and the first dynamic sealing device (5) and the second dynamic sealing device (6) are sleeved outside the cylinder (32) and are respectively sealed with the cylinder (32) through their sealing rings (52).

6. The anti-blocking and anti-sinking multi-directional pressure-maintaining coring device according to claim 5, characterized in that: The upper end surface of the disc (31) is grooved and equipped with two end surface sealing rings (35), and the drilling fluid flow channel hole (34) is located between the two end surface sealing rings (35).

7. The anti-blocking and anti-sinking multi-directional pressure-maintaining coring device according to claim 5 or 6, characterized in that: A connecting hole (33) is provided in the center of the upper end surface of the disk (31), the lower end of the center rod (2) is connected to the connecting hole (33), and a plurality of drilling fluid flow channel holes (34) are arranged around the connecting hole (33) at equal intervals in the circumferential direction.

8. The anti-blocking and anti-sinking multi-directional pressure-maintaining coring device according to claim 1, 5 or 6, characterized in that: The outer surface of the central rod (2) is provided with a spiral groove (21).

9. The anti-blocking and anti-sinking multi-directional pressure-maintaining coring device according to claim 1, characterized in that: A one-way valve (7) is installed on the side wall of the outer cylinder (1), and the one-way valve (7) is located between the first dynamic sealing device (5) and the second dynamic sealing device (6).

10. A method for using a multi-directional pressure-maintaining coring device for preventing blockage and sinking according to any one of claims 1 to 9, characterized in that: The following steps are involved: After the corer is installed, a seal is formed between the core barrel (3) and the first dynamic sealing device (5) and the second dynamic sealing device (6), and the interior of the pressure chamber is in a completely sealed state; in the sealed state, a protective gas is filled into the system to form a gas barrier; When the coring device is lowered to the bottom of the target hole, the drilling fluid flows in the spiral groove (21) on the outer surface of the center rod (2). When the flow rate of the drilling fluid reaches a first predetermined value, the center rod (2) can start to rotate under the action of the drilling fluid, driving the core barrel (3) to rotate together; when the coring operation is carried out, the drilling fluid flow rate is reduced to a second predetermined value, and the center rod (2) stops rotating.

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