A core sampling device with anti-blocking, anti-settling and multi-directional pressure maintaining functions and its usage method

Abstract

The present invention relates to a core sampling device with anti-blocking, anti-settling and multi-directional pressure maintaining functions and its usage method, which includes an outer cylinder, a central rod, a core barrel, a flap valve, a first dynamic sealing device and a second dynamic sealing device. The core barrel is located inside the outer cylinder, the lower end of the central rod is connected to the core barrel, and the flap valve includes a valve seat and a valve flap; the first dynamic sealing device and the second dynamic sealing device are coaxially installed inside the outer cylinder, and the first dynamic sealing device and the second dynamic sealing device are respectively located above and below the flap valve; both the first dynamic sealing device and the second dynamic sealing device include a cylindrical base body, an inner wall of the cylindrical base body is equipped with a sealing ring, and the cylindrical base body is sleeved outside the core barrel; there is a spiral groove on the outer wall of the central rod. The dynamic sealing device of the present application can prevent external drilling fluid, cuttings and other impurities from entering the pressure maintaining chamber and polluting the sealing environment of the pressure maintaining controller; the central rod of the present application can rotate under the action of the drilling fluid, drive the core barrel to rotate, and drive the circumferentially deposited drilling fluid to rotate, which can avoid the blockage of internal components caused by the deposition of drilling fluid.

Description

Technical Field

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

[0002] Traditional pressure-maintaining coring technology can only achieve vertical pressure-maintaining coring technology. The research and development team of the present invention has proposed a multi-directional pressure-maintaining coring technology based on magnetic control, realizing the anti-gravity self-driving of the flap valve and the initial self-sealing of magnetic control. For example, the structure-simple magnetic-trigger multi-directional pressure-maintaining coring device and rock sample extraction method disclosed in the Chinese patent document with the publication number of CN113958279A. The 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 the economic cost. However, when coring in multi-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 not only has to cope with high temperature, high pressure and corrosive fluids, but also must effectively prevent sediment and solid particles from entering the system to avoid seal failure. Sediment is suspended in the high-pressure fluid downhole and easily enters the key sealing parts of the pressure-maintaining system through the fluid channels, resulting in wear and blockage of the sealing surface and even causing system failure; larger solid particles (such as cuttings) in the reservoir may accumulate in the sealing area, hindering the normal operation of the system. In addition, when coring in multiple directions, especially horizontal coring, the mud drilling fluid precipitates inside the coring tool and cannot be discharged, resulting in the inability to trigger the pressure-maintaining action and the problem of pressure-maintaining failure is also worthy of attention. Summary of the Invention

[0004] The present invention provides an anti-blocking, anti-settling and multi-directional pressure-maintaining coring device and a using method thereof to solve the above technical problems.

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

[0006] An anti-blocking, anti-settling and multi-directional pressure-maintaining coring device includes an outer barrel, a central rod, a core barrel, a flap valve, a first dynamic sealing device and a second dynamic sealing device. The core barrel is located inside the outer barrel, and the lower end of the central rod is connected to the core barrel. The flap valve includes a valve seat and a valve flap. The valve seat is coaxially installed inside the outer barrel, and one end of the valve flap is movably connected to the upper end of the valve seat. When the valve flap is opened, the core barrel can pass through the valve seat. The first dynamic sealing device and the second dynamic sealing device are coaxially installed inside the outer barrel. The first dynamic sealing device is located above the flap valve, and the second dynamic sealing device is located below the flap valve. Both the first dynamic sealing device and the second dynamic sealing device include a cylindrical base body. A sealing ring is installed on the inner wall of the cylindrical base body. The cylindrical base body 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] Specifically, a sealing ring is installed on the outer wall of the cylindrical base of the first dynamic sealing device.

[0008] Optionally, the outer cylinder 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, and the upper end of the second section is threadedly connected to the lower end of the third section. 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, realizing the 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, realizing the 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 adapted to 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 realized by the combined 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 central rod is connected to the disc; there are a plurality of drilling fluid flow channel holes on the disc, and the lower ends of the drilling fluid flow channel holes communicate with the inside of the cylinder. The first dynamic sealing device and the second dynamic sealing device are sleeved outside the cylinder and are respectively in sealing cooperation with the cylinder through their sealing rings.

[0012] Optionally, two end face sealing rings are installed in grooves on the upper end face of the disc, and the drilling fluid flow channel holes are located between the two end face sealing rings.

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

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

[0015] Optionally, a first magnetic member is installed on the valve flap, and a second magnetic member that is mutually exclusive with the first magnetic member is provided on the outer cylinder. When the valve flap is opened, the first magnetic member and the second magnetic member face each other.

[0016] A method for using a core sampling device with anti-blocking, anti-settling, and multi-directional pressure maintaining provided by the present application includes the following steps: After the core sampler is installed, a seal is formed between the core barrel, the first dynamic sealing device, and the second dynamic sealing device, and the inside of the pressure maintaining chamber 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 corer is lowered to the bottom of the target hole, the drilling fluid flows in the spiral groove on the outer surface of the central rod. When the flow rate of the drilling fluid reaches the first predetermined value, the central rod can start to rotate under the action of the drilling fluid and drive the core barrel to rotate together; when coring, the flow rate of the drilling fluid is reduced to the second predetermined value, and the central rod stops rotating;

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

[0019] 1. The present application is provided with dynamic sealing devices at both ends of the pressure-holding chamber. A seal is formed between the core barrel and the first dynamic sealing device and the second dynamic sealing device to prevent drilling fluid, cuttings and other impurities from entering the pressure-holding chamber and polluting the sealed environment of the pressure-holding controller; when coring, the second dynamic sealing device can effectively prevent cuttings from entering the interior of the pressure-holding chamber to form precipitation or abrasion, and the first dynamic sealing device effectively prevents drilling fluid from flowing through the pressure-holding chamber and the interior of the pressure-holding components to form precipitation; moreover, inert gas can be filled into it to form an internal pressure difference, effectively preventing mud and cuttings from entering the pressure-holding chamber under the action of hydrostatic head difference;

[0020] 2. The present application is provided with a spiral groove on the outer surface of the central rod. The central rod can rotate under the action of the drilling fluid and drive the core barrel to rotate, and drive the circumferential deposition of drilling fluid to rotate, which can avoid the blockage of internal components 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 central 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, effectively preventing the drilling fluid from depositing on the sealing surface of the flap valve and improving 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 following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and therefore should not be regarded as a limitation of the scope. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

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

[0024] Figure 2 is Figure 1 a cross-sectional view taken at C-C in;

[0025] Figure 3 is Figure 1 a partial enlarged view at A in;

[0026] Figure 4 isFigure 1 Partial enlarged view at position B in

[0027] Figure 5 For Figure 2 Partial enlarged view at position E in

[0028] Figure 6 For Figure 2 Partial enlarged view at position D in

[0029] Figure 7 For Figure 6 Cross-sectional view at F-F in

[0030] Figure 8 Structural schematic diagram of the core barrel in the embodiment

[0031] Figure 9 For Figure 8 Partial enlarged view at position G in

[0032] Figure 10 Stereogram of the first dynamic sealing device in the embodiment

[0033] Figure 11 Stereogram of the second dynamic sealing device in the embodiment

[0034] Figure 12 Cross-sectional view of the second dynamic sealing device in the embodiment Detailed implementation manners

[0035] To make the objectives, 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 with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0036] It should be noted that, without conflict, the implementation manners and features in the embodiments of the present invention can be combined with each other. It should be noted that the embodiments in this specification are all described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts among the embodiments can be referred to each other.

[0037] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use, or the orientation or positional relationship commonly understood by those skilled in the art. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

[0038] In the description of the present invention, it should also be noted that unless otherwise clearly specified and defined, the terms "set", "install", "connect", and "couple" 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 directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] As Figures 1 - 6 shown, the anti-blocking, anti-settling and multi-directional pressure-holding coring device disclosed in this embodiment includes an outer cylinder 1, a central 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 inside the outer cylinder 1. The lower end of the central 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 inside the outer cylinder 1, and there is a sealing ring for sealing between the outer wall of the valve seat 41 and the inner wall of 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 barrel 3 can pass through the valve seat 41.

[0040] A first magnetic member 43 is installed on the valve flap 42, and a second magnetic member 44 that is mutually exclusive with the first magnetic member 43 is provided on the outer cylinder 1. When the valve flap 42 is opened, the first magnetic member 43 is directly opposite to the second magnetic member 44. The first magnetic member 43 and the second magnetic member 44 are permanent magnets.

[0041] As Figures 10 - 12 shown, both the first dynamic sealing device 5 and the second dynamic sealing device 6 include a cylindrical base body 51, and sealing rings 52 are installed on the inner walls of the cylindrical base bodies 51. A sealing ring 52 is installed on the outer wall of the cylindrical base body 51 of the first dynamic sealing device 5.

[0042] The first dynamic sealing device 5 and the second dynamic sealing device 6 are coaxially installed inside 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 cylindrical base body 51 is sleeved outside the core barrel 3 and is in sealing contact with the outer wall of the core barrel 3 through the sealing ring 52 on the inner wall.

[0043] In a possible design, there is an inner step 121 on the inner wall of the outer cylinder 1, 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 cylinder 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 face of the first section 11 to achieve 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 face 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 to achieve axial fixation of the cylindrical base 51 of the first dynamic sealing device 5.

[0046] Optionally, as Figures 10 - 12 shown, there is an inner step on the inner wall of the cylindrical base 51 that fits the sealing ring 52. The inner end of the sealing ring 52 abuts against the inner step of the cylindrical base 51. There is an annular groove on the end face of the cylindrical base 51 for installing the 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. The axial fixed installation of the sealing ring 52 is achieved through the combined 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 respectively installed at both ends of the cylindrical base 51.

[0048] In a possible design, as Figure 7 、 8 、 Figure 9 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 central rod 2 is connected to the disc 31, and there are a plurality of drilling fluid flow holes 34 on the disc 31. The lower ends of the drilling fluid flow holes 34 communicate with the inside of the cylinder 32. Two end face sealing rings 35 are installed in grooves on the upper end face of the disc 31. The drilling fluid flow holes 34 are located between the two end face sealing rings 35. The cylindrical bases 51 of the first dynamic sealing device 5 and the second dynamic sealing device 6 are sleeved outside the cylinder 32 and are respectively in sealing cooperation with the cylinder 32 through the sealing rings 52. The lower end of the core sampler abuts against the flap valve 4, and the end face sealing ring 35 is used to seal the upper part of the core sampler and form a static seal with the top.

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

[0050] In some embodiments, there is a spiral groove 21 on the outer surface of the center rod 2, 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] The working principle of this embodiment: In the multi-directional pressure-maintaining coring system, after the coring tool is installed, the inside of the pressure-maintaining chamber is in a completely sealed state. The specific sealing structure is as follows: A rotary dynamic seal and an axial dynamic seal are formed between the core barrel 3 and the first dynamic seal device 5 and the second dynamic seal device 6 to prevent external fluids and impurities from entering the pressure-maintaining chamber; A seal is formed between the first dynamic seal device 5, the second dynamic seal device 6 and the pressure-maintaining chamber to ensure the stability of the double-layer seal structure.

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

[0053] When the coring tool is lowered to the target hole bottom, 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 movement can effectively stir the drilling fluid and prevent the drilling fluid from precipitating inside the coring tool, thereby avoiding blockage of internal components caused by drilling fluid deposition; When the flow rate of the drilling fluid decreases to the second predetermined value during coring operation, the center rod 2 stops rotating to prevent disturbing the core and avoid damage to the core during coring. It can greatly improve the efficiency of coring operation and the integrity of the sample.

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

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

[0056] The dynamic sealing device realizes rotary 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. When lifting the core barrel, it can also ensure the sealing when the core barrel moves axially.

[0057] In this embodiment, by combining various technical means such as a dynamic sealing device, a drilling fluid flow passage hole, a spiral center rod, and a permanent magnet auxiliary seal, the environmental stability of the pressure maintaining system is ensured, and the reliable operation of the multi-directional pressure maintaining coring system in the complex downhole environment can be ensured. 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 the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A core sampling device with multi-directional pressure maintaining for preventing blockage and sinking, characterized in that, It includes an outer cylinder (1), a central 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 inside the outer cylinder (1), and the lower end of the central 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 inside the outer cylinder (1), and 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). The first dynamic sealing device (5) and the second dynamic sealing device (6) are coaxially installed inside 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). Both the first dynamic sealing device (5) and the second dynamic sealing device (6) include a cylindrical base body (51). Sealing rings (52) are installed on the inner walls of the cylindrical base bodies (51). The cylindrical base bodies (51) are sleeved outside the core barrel (3), and the sealing rings (52) on the inner walls of the cylindrical base bodies (51) are in sealing contact with the outer wall of the core barrel (3). The outer cylinder (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). The upper end of the cylindrical base body (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 body (51) of the second dynamic sealing device (6) abuts against the upper end face of the first section (11), realizing the axial fixation of the cylindrical base body (51) of the second dynamic sealing device (6). The upper end of the cylindrical base body (51) of the first dynamic sealing device (5) abuts against the lower end face of the third section (13), and the lower end of the cylindrical base body (51) of the first dynamic sealing device (5) abuts against the inner step (121) of the second section (12), realizing the axial fixation of the cylindrical base body (51) of the first dynamic sealing device (5).

2. The multi-directional pressure-maintaining coring device for preventing blockage and sinking according to claim 1, characterized in that, Sealing rings (52) are installed on the outer wall of the cylindrical base body (51) of the first dynamic sealing device (5).

3. The anti-blocking, anti-settling and multi-directional pressure-maintaining coring device according to claim 1 or 2, characterized in that, There are inner steps on the inner wall of the cylindrical base body (51) that are adapted to the sealing rings (52). The inner ends of the sealing rings (52) abut against the inner steps of the cylindrical base body (51). There are annular grooves on the end faces of the cylindrical base bodies (51) for installing fixing rings (53). The fixing rings (53) are installed in the annular grooves and fixed to the cylindrical base bodies (51) by screws (54). The fixing rings (53) are located outside the outer ends of the sealing rings (52). The axial fixation of the sealing rings (52) is realized through the combined action of the inner steps and the fixing rings (53).

4. The multi-directional pressure-maintaining coring device for preventing blockage and sinking according to claim 1, characterized in that, 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), and the lower end of the central rod (2) is connected to the disc (31). The disc (31) is provided with a plurality of drilling fluid flow channel holes (34). The lower ends of the drilling fluid flow channel holes (34) communicate with the inside of the cylinder (32). The first dynamic sealing device (5) and the second dynamic sealing device (6) are sleeved outside the cylinder (32) and are respectively in sealing fit with the cylinder (32) through their sealing rings (52).

5. The multi-directional pressure-maintaining coring device for preventing blockage and sinking according to claim 4, wherein Two end face sealing rings (35) are installed in grooves on the upper end face of the disc (31). The drilling fluid flow channel holes (34) are located between the two end face sealing rings (35).

6. The anti-blocking, anti-settling and multi-directional pressure-maintaining coring device according to claim 4 or 5, characterized in that, A connection hole (33) is provided at the center of the upper end face of the disc (31). The lower end of the center rod (2) is connected to the connection hole (33). A plurality of drilling fluid flow channel holes (34) are arranged at equal intervals in the circumferential direction around the connection hole (33).

7. A plugging and sinking prevention and multi-directional pressure maintaining coring device according to claim 1, 4 or 5, characterized in that, The outer surface of the center rod (2) has a spiral groove (21).

8. The multi-directional pressure maintaining coring device for preventing blockage and sinking according to claim 1, characterized in that, A check valve (7) is installed on the side wall of the outer cylinder (1). The check valve (7) is located between the first dynamic sealing device (5) and the second dynamic sealing device (6).

9. The usage method of an anti-blocking, anti-settling and multi-directional pressure-maintaining coring device according to any one of claims 1-8, characterized in that, It includes the following steps: After the core sampler is installed, a seal is formed between the core barrel (3), the first dynamic sealing device (5) and the second dynamic sealing device (6), and the inside of the pressure holding 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 core sampler 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 the first predetermined value, the center rod (2) can start to rotate under the action of the drilling fluid and drive the core barrel (3) to rotate together; when core sampling is performed, the flow rate of the drilling fluid is reduced to the second predetermined value and the center rod (2) stops rotating.

Images