A new type of plugging device that provides drilling fluid circulation channels

Abstract

This invention relates to the field of downhole operation technology and is a novel plugging device that provides a drilling fluid circulation channel. It includes a connecting sub, a guide string, a pressure seat valve, a fracture disc, a one-way valve assembly, a protective sleeve, a plugging bag, and a guide shoe. A guide string with its lower end positioned below it is fixedly installed on the inner side of the middle of the connecting sub, and a protective sleeve with its lower end positioned below the guide string is fixedly installed on the outer side of the lower end of the connecting sub. This invention has a reasonable and compact structure and is easy to use. By setting up a fracture disc to seal the central channel, it prevents drilling fluid from entering the plugging bag, which could cause the plugging bag to detach prematurely or even shear the second shear pin, leading to plugging failure. By sequentially connecting the corresponding side flow openings, the first side opening, and the second side opening from the inside out, an independent drilling fluid circulation channel is established, avoiding interference with other downhole operations. It features quantitative, controllable, and stable operation.

Description

Technical Field

[0001] This invention relates to the field of downhole operation technology and is a novel plugging device that provides a drilling fluid circulation channel. Background Technology

[0002] When encountering fractured or weakly cemented formations, or formations with well-developed fractures during drilling, lost circulation (WS) becomes a significant problem. Drilling fluid leaks out from formation fractures and cavities, disrupting drilling operations. This is especially true when the fractures or cavities are large, where drilling fluid may completely escape, making drilling impossible. In such cases, plugging the lost circulation is essential. Currently, conventional methods using injection of plugging slurry or cement slurry result in continued leakage along the fractures and cavities, failing to create an effective seal. Controlled plugging tools utilize plugging material storage bags. Under pump pressure and the weight of the plugging slurry or cement slurry, it enters the storage bag, forcing the bag into the fractures and cavities. The plugging material effectively aggregates within the same area of ​​the fractures and cavities, forming bridging and filling. Because the plugging slurry or cement slurry is stored in the bag, leakage into the fractures and cavities is prevented.

[0003] Chinese patent document CN 212428712 U discloses a slurry bag-type leak-stopping tool capable of circulating drilling fluid. The tool comprises an outer sleeve containing, from top to bottom, a guide pipe, a flow-diverting pressure seat, a flow-diverting short section, and a cement slurry bag. The outer sleeve has an external opening on its side wall, and the guide pipe has a first guide opening on its side wall. Fluid in the guide pipe can exit the outer sleeve through the external opening, and the fluid in the guide pipe can also sequentially enter the cement slurry bag through the first guide opening and the flow-diverting short section. This slurry bag-type leak-stopping tool has the following technical defect: when drilling fluid is lowered, it sequentially passes through the first guide opening, the upper annular cavity, the second flow channel, and the flow-diverting short section directly into the cement slurry bag, causing the cement slurry bag to detach prematurely, resulting in leak-stopping failure.

[0004] Chinese patent document CN 113482569 A discloses a multi-stage separating cement slurry plugging tool for installation at the bottom end of a drilling string. The tool comprises: a body with an external pressure relief hole on its outer wall and a plugging groove at its bottom end; a sliding sleeve with an inner hole extending axially through it, slidably mounted within the body, the outer wall of which has an internal pressure relief hole communicating with the inner hole, the upper end of which communicates with the lower end of the borehole of the drilling string; and at least two plugs for slidingly positioned within the borehole or inner hole, the plugs being movable from the borehole to the inner hole, the uppermost plug being the upper plug and the lower plug being the lower plug, with a storage space for accommodating cement slurry formed between the upper and lower plugs. The system includes: a space; a sealing assembly installed at the bottom of the body with a certain pre-tightening force, sealing the opening of the flushing groove, forming a flushing cavity between the flushing groove and the sealing assembly; a first limiting mechanism for engaging with the upper plug; a second limiting mechanism for engaging with the sliding sleeve; an upper sealing plate fixed in the inner hole by a certain bonding force provided by the third limiting mechanism, with the inner pressure relief hole located above the upper sealing plate and the sealing assembly located below the upper sealing plate; a cement slurry bag assembly fixed at the bottom of the body by a certain bonding force provided by the fourth limiting mechanism, with the cement slurry bag in the cement slurry bag assembly communicating with the bottom of the inner hole; and a fifth limiting mechanism for engaging with the inner pressure relief hole, allowing the sliding sleeve to move downward within the body. The device sequentially features a pressure relief position, a plugging position, and a coupling position. When the sliding sleeve is in the pressure relief position, the external pressure relief hole and the internal pressure relief hole are connected, while the internal pressure relief hole and the plugging cavity are not connected. The first limiting mechanism provides resistance between the sliding sleeve and the lower plug, allowing the sliding sleeve to move downwards synchronously with the lower plug to the plugging position. When the sliding sleeve is in the plugging position, the external pressure relief hole and the internal pressure relief hole are offset and not connected. The piston cavity formed between the lower plug and the upper sealing plate is connected to the plugging cavity through the internal pressure relief hole, and the sliding sleeve automatically engages with the second limiting mechanism. The second limiting mechanism provides a certain bonding force between the sliding sleeve and the body, fixing the sliding sleeve to the body. After the lower plug overcomes the resistance of the first limiting mechanism... During the downward movement until it contacts the upper sealing plate, the second limiting mechanism keeps the sliding sleeve stationary, and the sealing assembly separates from the main body; the third limiting mechanism is set so that the lower plug can push the upper sealing plate to drive the sliding sleeve to overcome the binding force of the second limiting mechanism and move the sliding sleeve to the coupling position; when the sliding sleeve is in the coupling position, the fifth limiting mechanism automatically engages the inner pressure relief hole, and the cement slurry bag assembly forms an obstacle to the downward movement of the sliding sleeve; and the fourth limiting mechanism is set so that during the downward movement of the lower plug after overcoming the binding force of the third limiting mechanism, the cement slurry bag assembly remains fixed on the main body, the upper sealing plate separates from the sliding sleeve, and the cement slurry from the lower plug, the upper sealing plate, and the storage space enters the cement slurry bag;The fifth limiting mechanism is set to provide a certain resistance to the upper blockage, allowing the sliding sleeve to move downward synchronously with the upper blockage. The sliding sleeve pushes the cement slurry bag assembly to overcome the binding force of the fourth limiting mechanism, thus separating the cement slurry bag assembly from the main body. This multi-stage separation cement slurry plugging tool has the following technical defects: (1) complex structure; (2) complex plugging process, difficult to operate. Summary of the Invention

[0005] This invention provides a novel plugging device that provides a drilling fluid circulation channel, overcoming the shortcomings of the prior art. It can effectively solve the problem that the cement slurry bag of existing plugging tools will fall off prematurely, and can further solve the problem that existing plugging tools have complex structures and are not easy to use for plugging operations.

[0006] The technical solution of this invention is achieved through the following measures: A novel plugging device for providing a drilling fluid circulation channel includes a connecting sub, a flow guide string, a pressure seat valve, a rupture disc, a one-way valve assembly, a protective sleeve, a plugging bag, and a guide shoe. A flow guide string with its lower end positioned below it is fixedly installed on the inner side of the middle portion of the connecting sub. A protective sleeve with its lower end positioned below the flow guide string is fixedly installed on the outer side of the lower end of the connecting sub. At least two downward-opening side flow notches are provided at circumferential intervals at the lower end of the flow guide string. A lower shear pin is fixedly installed on the outer side of the lower end of the flow guide string. The pressure-bearing valve seat is located below it. The pressure-bearing valve seat has a central channel in the center. Each pressure-bearing valve seat corresponding to the position of the side flow notch has a first side opening that is open inside and out. Each protective sleeve corresponding to the position of the first side opening has a second side opening that is open inside and out. A rupture disc that can block the central channel and can release the blockage of the central channel after pressure buildup is fixedly installed at the lower end of the pressure-bearing valve seat. A one-way valve assembly is fixedly installed on the outer side of the lower end of the pressure-bearing valve seat. A leak-stopping bag is fixedly installed at the lower end of the one-way valve assembly. A guide shoe is fixedly installed at the lower end of the protective sleeve by a second shear pin.

[0007] The following are further optimizations and / or improvements to the above-mentioned technical solution:

[0008] The above may also include a front rubber plug and a rear rubber plug. The lower end of the flow guide column is provided with a front rubber plug that can seal the side flow opening. The center of the front rubber plug is provided with a vertically penetrating leak-stopping liquid channel. The front rubber plug is provided with a rear rubber plug whose upper end is located above it and can seal the leak-stopping liquid channel.

[0009] The aforementioned central channel may include a first mounting hole, a second mounting hole, and a third mounting hole connected sequentially from top to bottom. The inner diameters of the first mounting hole, the second mounting hole, and the third mounting hole decrease sequentially from top to bottom. An outer annular groove is provided on the outer side of the lower end of the front rubber plug, and the lower end of the front rubber plug is located inside the second mounting hole. The leak-stopping fluid channel includes a receiving hole and a liquid passage hole connected vertically. The receiving hole is a frustum shape that is larger at the top and smaller at the bottom. The rear rubber plug includes a frustum portion and a straight rod portion that are fixedly installed together from top to bottom. The frustum portion is located inside the receiving hole and its upper end is located above the front rubber plug. The straight rod portion is located inside the liquid passage hole and its lower end is located inside the third mounting hole.

[0010] The aforementioned one-way valve assembly may include a flow guide cone, a valve head, a valve stem, a valve seat, and a return spring. The flow guide cone includes an upper mounting part, a flared part, and a lower mounting part, which are fixedly installed together from top to bottom. The flared part is a frustum shape, wider at the top and narrower at the bottom. The upper mounting part, with its lower end located below it, is fixedly installed on the outer side of the lower end of the pressure seat valve. A leak-stopping bag is fixedly installed on the outer side of the lower end of the lower mounting part. A valve seat is fixedly installed on the inner side of the lower end of the lower mounting part. A valve stem hole is provided in the center of the valve seat. At least two flow holes are provided at circumferential intervals on the upper edge of the valve seat corresponding to the outer position of the valve stem hole. A valve stem, with its upper end located above the valve seat, is provided in the valve stem hole. A valve head is fixedly installed on the upper end of the valve stem. A sealing platform is provided on the inner side of the upper end of the lower mounting part. The outer side of the lower part of the valve head can contact and seal with the inner side of the sealing platform. A return spring is provided on the outer side of the valve stem corresponding to the position between the valve head and the valve seat.

[0011] The lower end of the aforementioned flow guide column may have four downward-facing side flow openings evenly distributed along the circumference, and the corresponding side flow openings, the first side opening, and the second side opening are connected sequentially from the inside to the outside.

[0012] The inner side of the middle section of the aforementioned connecting short section can be fixedly installed together with the outer side of the upper end of the guide tube column by means of a threaded connection; the outer side of the lower end of the connecting short section can be fixedly installed together with the inner side of the upper end of the protective sleeve by means of a threaded connection; the outer side of the lower end of the pressure seat valve can be fixedly installed together with the inner side of the upper end of the one-way valve assembly by means of a threaded connection.

[0013] The aforementioned leak-sealing bag can be made of elastic or flexible material. The leak-sealing bag is folded and stored inside the protective sleeve. After the fluid enters, the leak-sealing bag can detach from the protective sleeve and expand into an open state.

[0014] This invention has a reasonable and compact structure and is easy to use. By setting a rupture disc to seal the central channel, it prevents drilling fluid from entering the plugging bag, which could cause the plugging bag to fall off prematurely or even cut the second shear pin, resulting in the failure of the plugging operation. By connecting the side flow opening, the first side opening and the second side opening in sequence from the inside to the outside, an independent drilling fluid circulation channel is established, which avoids affecting other downhole operations. It has the characteristics of quantitative, controllable and stable operation. Attached Figure Description

[0015] AppendixFigure 1 These are schematic diagrams of the main cross-sectional structure of embodiments 1 to 7 of the present invention.

[0016] Appendix Figure 2 For the appendix Figure 1 A three-dimensional structural diagram of the central guide tube column.

[0017] Appendix Figure 3 For the appendix Figure 1 A three-dimensional structural diagram of a pressure-bearing seat valve.

[0018] Appendix Figure 4 For the appendix Figure 1 A three-dimensional structural diagram of the central guide cone.

[0019] The codes in the attached diagram are as follows: 1 is the connecting section, 2 is the flow guide string, 3 is the pressure seat valve, 4 is the rupture disc, 5 is the protective sleeve, 6 is the plugging bag, 7 is the guide shoe, 8 is the side flow notch, 9 is the first side opening, 10 is the second side opening, 11 is the front rubber plug, 12 is the rear rubber plug, 13 is the upper mounting part, 14 is the bell mouth part, 15 is the lower mounting part, 16 is the valve head, 17 is the valve stem, 18 is the valve seat, 19 is the return spring, and 20 is the sealing platform. Detailed Implementation

[0020] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0021] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0022] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0023] Example 1: As shown in the attached document Figure 1 , 2As shown in Figures 3 and 4, this novel plugging device for providing a drilling fluid circulation channel includes a connecting sub 1, a flow guide string 2, a pressure seat valve 3, a rupture disc 4, a one-way valve assembly, a protective sleeve 5, a plugging bag 6, and a guide shoe 7. A flow guide string 2 with its lower end positioned below it is fixedly installed on the inner side of the middle of the connecting sub 1. A protective sleeve 5 with its lower end positioned below the flow guide string 2 is fixedly installed on the outer side of the lower end of the connecting sub 1. At least two downward-facing side flow notches 8 are provided at circumferential intervals at the lower end of the flow guide string 2. A pressure seat valve with its lower end positioned below it is fixedly installed on the outer side of the lower end of the flow guide string 2 by a first shear pin. The valve seat 18 has a central channel in the center. Each pressure valve seat 18 corresponding to the position of each side flow notch 8 has a first side opening 9 that is open inside and out. Each protective sleeve 5 corresponding to the position of the first side opening 9 has a second side opening 10 that is open inside and out. The lower end of the pressure seat valve 3 is fixedly installed with a rupture disc 4 that can block the central channel and can release the blockage of the central channel after pressure buildup. A one-way valve assembly is fixedly installed on the outer side of the lower end of the pressure valve seat 18. A leak-stopping bag 6 is fixedly installed on the lower end of the one-way valve assembly. A guide shoe 7 is fixedly installed on the lower end of the protective sleeve 5 by a second shear pin. During operation, by setting the fracture plate 4 to seal the central channel, drilling fluid is prevented from entering the plugging bag 6, which could cause the plugging bag 6 to detach prematurely or even shear the second shear pin, resulting in plugging failure. An independent drilling fluid circulation channel is established by sequentially connecting the corresponding side flow opening 8, the first side opening 9, and the second side opening 10 from the inside out, thus avoiding interference with other downhole operations. During plugging, two rubber plugs are inserted into the drill string sequentially. The first plug seals the side flow opening 8 and fractures the fracture plate 4, initiating the plugging operation. The second plug seals the central channel and shears the second shear pin. The first shear pin breaks, ending the leak-sealing operation and allowing for the quantitative release of the leak-sealing fluid while simultaneously releasing the device. By placing the leak-sealing bag 6 at the bottom of the one-way valve assembly, when the leak-sealing fluid enters the bag 6, it causes the bag to expand under pressure, slide out of the protective sleeve 5, fill the leak area, and solidify at the leaking stratum, thus achieving the purpose of leak sealing. By installing the guide shoe 7 at the end of the protective sleeve 5 using the second shear pin, the integrity of the leak-sealing bag 6 can be ensured during the lowering process. When the bag 6 expands and slides out of the protective sleeve 5, the guide shoe 7 is subjected to force and shears the second shear pin, thus achieving the purpose of removing the guide shoe 7.

[0024] The novel plugging device that provides drilling fluid circulation channels can be further optimized and / or improved according to actual needs:

[0025] Example 2: As shown in the attached document Figure 1 , 2Figures 3 and 4 also include a front rubber plug 11 and a rear rubber plug 12. The lower inner side of the guide string 2 is provided with a front rubber plug 11 capable of sealing the lateral flow opening 8. The front rubber plug 11 has a vertically penetrating plugging fluid channel in its center. Inside the front rubber plug 11 is a rear rubber plug 12, with its upper end positioned above it and capable of sealing the plugging fluid channel. During plugging operations, the front rubber plug 11 is first deployed, followed by a measured amount of plugging fluid, and then the rear rubber plug 12 is deployed, thus achieving quantitative plugging. After the plugging fluid is deployed, it pushes the front rubber plug 11 into the guide string 2, thereby sealing the lateral flow opening 8 and closing the drilling fluid circulation channel. The lower end of the front rubber plug 11 is positioned inside the pressure seat valve 3 and rests on the fracture disc 4, thereby fracturing the fracture disc 4 and establishing a plugging fluid circulation channel. This allows the plugging fluid to pass through the guide string 2 and the front rubber plug 11... Open the one-way valve assembly, and the fluid will eventually flow into the plugging bag 6. After the required amount of plugging fluid has been prepared, the rear rubber plug 12 is then inserted. The rear rubber plug 12 can isolate the plugging fluid from the drilling fluid. Under the pressure of the surface pump, the upper surface of the rear rubber plug 12 and the front rubber plug 11 are pressed together, thereby completely pressing the plugging fluid between the front rubber plug 11 and the rear rubber plug 12 into the plugging bag 6. Continue to pressurize, and the first shear pin between the pressure seat valve 3 and the guide string 2 is sheared, thus allowing the tool to be released.

[0026] Example 3: As shown in the attached document Figure 1 , 2 The central channel shown in Figures 3 and 4 includes a first mounting hole, a second mounting hole, and a third mounting hole connected sequentially from top to bottom. The inner diameters of the first, second, and third mounting holes decrease sequentially from top to bottom. An outer annular groove is provided on the outer side of the lower end of the front rubber plug 11, and the lower end of the front rubber plug 11 is located within the second mounting hole. The sealing fluid channel includes a receiving hole and a passing hole connected vertically. The receiving hole is a frustum shape, wider at the top and narrower at the bottom. The rear rubber plug 12 includes a frustum portion and a straight rod portion fixedly installed together from top to bottom. The frustum portion is located within the receiving hole, with its upper end above the front rubber plug 11. The straight rod portion is located within the passing hole, with its lower end within the third mounting hole. This design ensures a tight seal while enabling better sealing operations during use.

[0027] Example 4: As shown in the appendix Figure 1 , 2The one-way valve assembly shown in Figures 3 and 4 includes a flow guide cone, a valve head 16, a valve stem 17, a valve seat 18, and a return spring 19. The flow guide cone includes an upper mounting part 13, a bell mouth part 14, and a lower mounting part 15, which are fixedly installed together from top to bottom. The bell mouth part 14 is a frustum shape, wider at the top and narrower at the bottom. The upper mounting part 13, with its lower end located below it, is fixedly installed on the outer side of the lower end of the pressure seat valve 3. A leak-stopping bag 6 is fixedly installed on the outer side of the lower end of the lower mounting part 15. A leak-stopping bag 6 is fixedly installed on the inner side of the lower end of the lower mounting part 15. The valve seat 18 has a valve stem 17 hole in its center. At least two flow holes are spaced circumferentially around the valve seat 18 corresponding to the outer position of the valve stem 17 hole. A valve stem 17, with its upper end positioned above the valve seat 18, is housed within the valve stem 17 hole. A valve head 16 is fixedly mounted on the upper end of the valve stem 17. A sealing platform 20 is provided on the inner side of the upper end of the lower mounting part 15. The lower outer side of the valve head 16 can contact and seal with the inner side of the sealing platform 20. A return spring 19 is provided on the outer side of the valve stem 17 corresponding to the position between the valve head 16 and the valve seat 18. During use, this design facilitates the introduction of sealing fluid into the sealing bag 6, preventing backflow of the sealing fluid within the sealing bag 6 and thus avoiding interference with the sealing operation.

[0028] Example 5: As shown in the attached document Figure 1 , 2 As shown in Figures 3 and 4, the lower end of the guide string 2 has four downward-facing side flow notches 8 evenly distributed along the circumference. The side flow notches 8, the first side opening 9, and the second side opening 10 at corresponding positions are connected sequentially from the inside to the outside. During use, this setup allows for the establishment of a complete and unobstructed drilling fluid channel before the start of the plugging operation.

[0029] Example 6: As attached Figure 1 , 2 As shown in Figures 3 and 4, the inner side of the middle section of connecting short section 1 is fixedly installed to the outer side of the upper end of the guide tube column 2 via a threaded connection; the outer side of the lower end of connecting short section 1 is fixedly installed to the inner side of the upper end of the protective sleeve 5 via a threaded connection; the outer side of the lower end of the pressure seat valve 3 is fixedly installed to the inner side of the upper end of the one-way valve assembly via a threaded connection. This arrangement facilitates the disassembly and assembly of each component during use.

[0030] Example 7: As attached Figure 1 , 2 The leak-sealing bag 6 shown in Figures 3 and 4 is made of elastic or flexible material. The leak-sealing bag 6 is folded and stored inside the protective sleeve 5. After fluid enters, the leak-sealing bag 6 detaches from the protective sleeve 5 and expands. This design allows for better leak sealing during use.

[0031] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A novel lost circulation device that provides a path for circulation of drilling fluid, characterized in that The utility model provides a kind of well drilling pipe, including connecting short section, flow guide pipe column, pressure seat valve, rupture disc, one-way valve assembly, protective sleeve, leaking stopper bag and guide shoe, connecting short section middle inside fixed installation has lower end below it flow guide pipe column, connecting short section lower end outside fixed installation has lower end below it protective sleeve;Flow guide pipe column lower end is circumferentially spaced and is equipped with at least two open downward side flow aperture, flow guide pipe column lower end outside is fixedly installed with lower end below it pressure valve seat by first shear pin, pressure valve seat center is equipped with center passage, corresponding each side flow aperture position's pressure valve seat is equipped with first side aperture that passes through inside and outside, corresponding each first side aperture position's protective sleeve is equipped with second side aperture that passes through inside and outside;Pressure seat valve lower end is fixedly installed with the rupture disc that can block center passage and can release the blocking center passage after pressure accumulation, pressure valve seat lower end outside is fixedly installed with one-way valve assembly, one-way valve assembly lower end is fixedly installed with leaking stopper bag, protective sleeve lower end is fixedly installed with guide shoe by second shear pin.

2. The novel lost circulation device providing a path for drilling fluid circulation according to claim 1, wherein It also includes front rubber plug and rear rubber plug, flow guide pipe column lower end inside is equipped with the front rubber plug that can block side flow aperture, front rubber plug center is equipped with up-down through leaking stopper liquid passage, front rubber plug is equipped with the rear rubber plug that can block leaking stopper liquid passage and upper end is located above it inside.

3. The novel lost circulation device providing a path for drilling fluid circulation according to claim 2, wherein Center passage includes first installation hole, second installation hole and third installation hole sequentially communicated from top to bottom, the inner diameter of first installation hole, the inner diameter of second installation hole and the inner diameter of third installation hole sequentially decrease from top to bottom, the outer ring groove is equipped on the lower end outside of front rubber plug, and the lower end of front rubber plug is located in second installation hole;Leaking stopper liquid passage includes up-down through receiving hole and liquid passage, receiving hole is circular truncated cone with upper large lower small, rear rubber plug includes circular truncated cone part and straight rod part fixedly installed together from top to bottom, circular truncated cone part is located in receiving hole and upper end is located above front rubber plug, and straight rod part is located in liquid passage and lower end is located in third installation hole.

4. A new lost circulation device providing a path for drilling fluid circulation according to claim 1 or 2 or 3, characterized in that One-way valve assembly includes flow guide cone tube, valve head, valve rod, valve seat and reset spring, flow guide cone tube includes upper installation part, horn mouth part and lower installation part fixedly installed together from top to bottom, horn mouth part is circular truncated cone with upper large lower small, pressure seat valve lower end outside is fixedly installed with lower end below it upper installation part, and leaking stopper bag is fixedly installed with lower end below it lower installation part outside;Lower installation part lower end inside is fixedly installed with valve seat, valve seat center is equipped with valve rod hole, at least two flow holes are circumferentially spaced and equipped on valve seat outside corresponding valve rod hole position, valve rod hole is equipped with valve rod with upper end above valve seat inside, valve rod upper end is fixedly installed with valve head, lower installation part upper end inside is equipped with sealing platform, valve head lower part outside can be in contact with sealing platform inside, and reset spring is equipped on valve rod outside corresponding position between valve head and valve seat.

5. A new type of lost circulation device providing a circulation channel for drilling fluid according to claim 1 or 2 or 3, characterized in that Flow guide pipe column lower end is circumferentially spaced and uniformly distributed with four open downward side flow apertures, and corresponding position side flow aperture, first side aperture and second side aperture sequentially communicate from inside to outside.

6. The novel lost circulation device providing a path for drilling fluid circulation according to claim 4, wherein Flow guide pipe column lower end is circumferentially spaced and uniformly distributed with four open downward side flow apertures, and corresponding position side flow aperture, first side aperture and second side aperture sequentially communicate from inside to outside.

7. A new lost circulation device providing a path for drilling fluid circulation according to claim 1 or 2 or 3 or 6, characterized in that The middle inner side of the connecting nipple is fixedly installed with the outer side of the upper end of the flow guide pipe column through threaded connection; the lower outer side of the connecting nipple is fixedly installed with the inner side of the upper end of the protection sleeve through threaded connection; and the lower outer side of the pressure bearing seat valve is fixedly installed with the inner side of the upper end of the one-way valve assembly through threaded connection.

8. The novel lost circulation device providing a path for drilling fluid circulation according to claim 4, wherein The middle inner side of the connecting nipple is fixedly installed with the outer side of the upper end of the flow guide pipe column through threaded connection; the lower outer side of the connecting nipple is fixedly installed with the inner side of the upper end of the protection sleeve through threaded connection; and the lower outer side of the pressure bearing seat valve is fixedly installed with the inner side of the upper end of the one-way valve assembly through threaded connection.

9. The novel lost circulation device providing a path for drilling fluid circulation according to claim 5, wherein The middle inner side of the connecting nipple is fixedly installed with the outer side of the upper end of the flow guide pipe column through threaded connection; the lower outer side of the connecting nipple is fixedly installed with the inner side of the upper end of the protection sleeve through threaded connection; and the lower outer side of the pressure bearing seat valve is fixedly installed with the inner side of the upper end of the one-way valve assembly through threaded connection.

10. A new lost circulation device providing a path for drilling fluid circulation according to claim 1 or 2 or 3 or 6 or 8 or 9, characterized in that The material of the leaking stop bag is elastic or flexible material, the leaking stop bag is in a folded storage state in the protection sleeve, and the leaking stop bag can be separated from the protection sleeve and changed into an inflated and opened state after fluid enters.

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