Open type pump-free drilling tool and drilling construction method

Abstract

The invention discloses an open type pump-free drilling tool and a drilling construction method. The open type pump-free drilling tool comprises a drilling rod; the first internal circulation device comprises a shell which is of a hollow structure installed at the bottom of the drill rod, and through holes communicating with the outside are formed in the bottom face and the side face of an inner cavity of the shell correspondingly; the first movable ball is arranged in the inner cavity of the shell, and the diameter of the first movable ball is larger than that of the bottom surface through hole of the inner cavity; the circulating pipe is mounted at the bottom of the first internal circulating device and is hermetically communicated with a bottom surface through hole of an inner cavity of the first internal circulating device; the connector is of a sleeve structure installed at the bottom of the circulating pipe, and the upper portion of the inner ring face of the connector is connected with the circulating pipe in a matched and sleeved mode; the powder taking pipe is arranged on the outer side of the circulating pipe in a sleeving mode and connected with the top of the outer ring face of the connector in a matched and sleeving mode. The core barrel is mounted below the connector and is matched and sleeved with the bottom of the outer ring surface of the connector. According to the invention, the drilling tool is lifted up and down, so that the circulating liquid in the well realizes local reverse circulation flow under the hydrostatic column pressure, and the purposes of removing rock powder, cooling the drill bit and improving the core recovery rate are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of shallow hole pumpless core drilling, and more specifically, to an open-type pumpless drilling tool and a drilling construction method. Background Art

[0002] Pumpless drilling is a common technical means in geological drilling, especially in the construction of complex formations, such as sand bailing at the bottom of the hole and coring in loose formations. Pumpless drilling is generally dry coring. On the one hand, it can obtain cores that are not disturbed by foreign substances for scientific research analysis and engineering design purposes. On the other hand, it can be well applied to water-scarce areas / environments. It does not require continuous delivery of drilling fluid into the hole to form a circulation. As long as there is water in the hole, drilling construction can be carried out.

[0003] However, conventional pumpless drilling tools have a limited range of application for apertures, and when faced with unstable and broken formations, they are prone to blockage and hollow cores during the coring process, resulting in difficulties in drilling construction and low core collection rates, which seriously affects construction efficiency.

[0004] In order to solve the above problems, it is necessary to design an open-type pumpless drill and a drilling construction method so that the pumpless drill can be better adapted to different construction conditions and improve the core recovery rate. Summary of the invention

[0005] The purpose of the present invention is to provide an open-type pumpless drilling tool and a drilling construction method. By lifting the drilling tool up and down, the circulating fluid in the well can achieve local reverse circulation flow under the hydrostatic column pressure, so as to achieve the purpose of removing rock powder, cooling the drill bit and improving the core recovery rate.

[0006] In order to achieve these purposes and other advantages according to the present invention, there is provided an open-ended pumpless drilling tool, comprising: Drill pipe; A first internal circulation device, comprising a housing, which is a hollow structure installed at the bottom of the drill pipe, and the bottom and side surfaces of the inner cavity are respectively provided with through holes communicating with the outside; a first movable ball, which is arranged in the inner cavity of the housing, and the diameter of the first movable ball is larger than the diameter of the through hole on the bottom surface of the inner cavity; A circulation pipe, which is installed at the bottom of the first internal circulation device and is sealed and connected to the bottom through hole of the inner cavity thereof; A connector, which is a sleeve structure installed at the bottom of the circulation pipe, and the upper part of the inner annular surface of the connector is sleeved with the circulation pipe; A powder extraction pipe, which is sleeved on the outside of the circulation pipe and is sleeved with the top of the outer annular surface of the connector; The core tube is installed below the connector and is sleeved with the bottom of the outer annular surface of the connector. A drill bit is mounted on the bottom of the core tube.

[0007] Preferably, the open-type pumpless drilling tool, the outer shell includes a top cover, a side panel and a base, which are assembled together to form a hollow structure, the top cover is fixedly connected to the drill rod and detachably connected to the side panel, the top cover is provided with a delivery hole, which connects the drill rod with the closed cavity, the diameter of the delivery hole is larger than the diameter of the first movable ball, the bottom of the top cover is also provided with a first baffle, which is configured to close the delivery hole and is detachably connected to the top cover, a plurality of side through holes are provided on the side panel at intervals along the circumferential direction, the base is provided with a bottom through hole and is fixedly connected to the circulation pipe.

[0008] Preferably, in the open-type pumpless drilling tool, a flow sensor is provided at the bottom through hole of the inner cavity, and the flow sensor is electrically connected to an external display device.

[0009] Preferably, in the open-type pumpless drilling tool, the connector and the circulation pipe, the core pipe and the powder extraction pipe are coaxially sleeved by threaded fitting, and the drill rod is coaxially arranged with the bottom through hole of the inner cavity and the circulation pipe.

[0010] Preferably, in the open-type pumpless drilling tool, the lower part of the inner ring surface of the connecting head is a conical surface which is narrow at the top and wide at the bottom, and a plurality of auxiliary circulation devices are provided between the inner and outer ring surfaces of the connecting head, which are arranged at intervals along the circumference of the connecting head, and any auxiliary circulation device comprises an auxiliary hole which is axially connected to the upper and lower end surfaces of the connecting head; a piston which is arranged in the auxiliary hole and is sealingly and slidably connected thereto; and two limiting mechanisms which are respectively arranged at both ends of the auxiliary hole, and any limiting mechanism is configured to prevent the piston from moving out of the auxiliary hole without restricting the flow of liquid.

[0011] Preferably, the open-type pumpless drilling tool is further provided with a plurality of second internal circulation devices between the inner and outer annular surfaces of the connecting head, which are arranged at intervals along the circumference of the connecting head, and any second internal circulation device includes a movable groove, which is opened at the upper end surface of the connecting head; a second circulation hole, which is opened at the lower end surface of the connecting head and connected to the bottom of the movable groove, and the diameter of the second circulation hole is smaller than the diameter of the bottom through hole of the inner cavity; a second movable ball, which is arranged in the movable groove, and the diameter of the second movable ball is larger than the diameter of the second circulation hole; a second baffle, which is fixed at the top opening of the movable groove and is arranged to limit the displacement of the second movable ball.

[0012] Preferably, in the open-type pumpless drilling tool, the core tube comprises a plurality of arc-shaped segments, the plurality of arc-shaped segments are continuously assembled along the circumferential direction to form a tubular structure, any two adjacent arc-shaped segments are detachably connected, and the inner wall roughness Ra of any arc-shaped segment is greater than 20 μm.

[0013] The present invention also provides a drilling construction method using an open-type pumpless drilling tool, comprising: S1, assembling the open-type pumpless drilling tool and performing drilling construction according to design requirements; S2. While drilling, the open pumpless drill bit is lifted and lowered in sequence to create bottom hole circulation, wherein when the drill bit is lifted upward, the circulating fluid mixed with rock powder and core in the well is sucked into the core tube, and when the drill bit is lowered, the circulating fluid mixed with rock powder in the core tube flushes the first movable ball through the circulation tube and enters the inner cavity of the shell, and then flows into the powder extraction tube through the side through hole of the inner cavity, the rock powder is precipitated in the powder extraction tube, and the remaining circulating fluid flows back to the well from the upper part of the powder extraction tube to participate in the next circulation; S3. Repeat the steps of S2 at a set frequency to achieve powder removal drilling through bottom hole circulation.

[0014] Preferably, in the drilling construction method, in S3, during normal footage, the open pumpless drill bit is repeatedly lifted and lowered at a conventional frequency to create bottom hole circulation; when the footage of the round is completed, the frequency of lifting the drill bit is reduced to gradually invalidate the circulation effect, thereby causing rock powder to stick to the drill and the core to be blocked until the core sampling work is completed.

[0015] The present invention has at least the following beneficial effects: 1. The present invention does not use a pump to flush the borehole during drilling. Instead, the drilling tool is lifted up and down, and the hydrostatic pressure in the well is used to make the circulating fluid form a local reverse circulation at the bottom of the well, so as to achieve the purpose of removing rock powder, cooling the drill bit and improving the core recovery rate; 2. The open-type pumpless drill of the present invention effectively improves the vacuum suction of the core when the drill is pulled up by arranging internal circulation devices in layers at different positions, and cooperates with the internal structure of the core tube and the connector. At the same time, it can disperse the pressure of the single-hole circulation of rock powder during the falling stage of the drill, so as to avoid a large amount of rock powder blocking the internal circulation hole of the drill, resulting in the inability to discharge powder normally, which affects the drilling construction efficiency; 3. The open-type pumpless drilling tool of the present invention can be equipped with a drill bit with a caliber of 150 mm or more, and is suitable for a variety of formation environments including soft and broken formations, which greatly improves the application scope of the pumpless drilling tool and has broad application prospects.

[0016] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The present invention is a schematic diagram of a cross-sectional structure of an open-type pumpless drilling tool according to an embodiment of the present invention.

[0018] Description of reference numerals: 1. Drill rod; 2. Casing; 21. First baffle; 22. Side through hole; 23. Base; 24. Flow sensor; 3. First movable ball; 4. Circulation pipe; 5. Connector; 6. Powder extraction pipe; 7. Core pipe; 71. Arc segment; 8. Auxiliary circulation device; 91. Movable groove; 92. Second circulation hole; 93. Second movable ball. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0020] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are commercially available unless otherwise specified; in the description of the present invention, the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and 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.

[0021] like Figure 1 As shown, the present invention provides an open-type pumpless drilling tool, comprising: Drill rod 1; The first internal circulation device comprises a housing 2, which is a hollow structure installed at the bottom of the drill pipe 1, and the bottom and side surfaces of the inner cavity are respectively provided with through holes communicating with the outside; a first movable ball 3, which is arranged in the inner cavity of the housing 2, and the diameter of the first movable ball 3 is larger than the diameter of the through hole on the bottom surface of the inner cavity; A circulation pipe 4, which is installed at the bottom of the first internal circulation device and is sealed and connected to the bottom through hole of the inner cavity thereof; A connector 5, which is a sleeve structure installed at the bottom of the circulation pipe 4, and the upper part of the inner annular surface of the connector 5 is sleeved with the circulation pipe 4; A powder extraction pipe 6, which is sleeved on the outside of the circulation pipe 4 and is sleeved with the top of the outer annular surface of the connector 5; The core tube 7 is installed below the connector 5 and is sleeved with the bottom of the outer annular surface thereof. A drill bit is mounted on the bottom of the core tube 7.

[0022] In the above technical solution, the first internal circulation device constitutes a pumpless takeover, the bottom through hole of the inner cavity is the first circulation hole, and the side through hole 22 of the inner cavity is the water outlet window. During the drilling process, the bottom of the drill tool is sealed by the bottom hole circulating fluid, and the core tube 7, the inner hole of the connector 5, the circulation tube 4 and the first circulation hole form a continuous and gradually narrowed closed space from bottom to top along the axial direction (vertical direction), and a vacuum adsorption structure is formed when the drill tool is lifted up from the bottom of the well (the first circulation hole is sealed by the first movable ball 3), and the bottom hole circulating fluid with rock powder is sucked into the core tube 7 under the action of the hydrostatic column pressure; and when the drill tool is quickly lowered, the circulating fluid in the closed space opens the first movable ball 3 under the action of the internal pressure to make it float, and the circulating fluid can carry the rock powder into the inner cavity of the shell 2, and then flow into the powder extraction pipe 6 through the water outlet window, and the rock powder is precipitated in the powder extraction pipe 6, and the remaining circulating fluid (clean water) can flow back to the well from the upper part of the powder extraction pipe 6. The upper pipe mouth of the powder extraction pipe 6 is provided with an opening (set in an inclined shape) for dumping rock powder to facilitate the subsequent recovery of rock powder. Thus, by repeatedly lifting and lowering the drill bit during the drilling process, a local reverse circulation effect can be formed at the bottom of the well, and the rock powder generated during the drilling process can be extracted into the powder extraction tube for precipitation, thereby assisting the rapid, smooth and stable drilling operation. In addition, the open-type pumpless drill bit can also be used to achieve core extraction operations in the above manner. When the drill bit is lifted, the circulating fluid containing rock powder and core enters the enclosed space. When the drill bit is lowered, the circulating fluid containing rock powder can continue to flow in the original circulation direction, thereby achieving core extraction in the core tube. Figure 1 The dotted line with an arrow in the middle shows the circulation flow direction of the bottom hole circulating fluid. The vacuum adsorption structure adopted by the present invention can achieve a stronger adsorption effect when the drill tool is lifted, improve the bottom hole circulation efficiency, and thus improve the drilling efficiency and core recovery rate; at the same time, the core is mainly lifted by pumpless drilling by vacuum "suction", the friction between the rock powder core and the inner wall of the core tube 7, and the sintering force formed after the bottom drill bit is dry drilled. When these three forces cannot overcome the self-weight of the core, the core will fall off. Therefore, the larger the diameter of the drill bit, the greater the difficulty of drilling and coring. This suction-enhanced drilling tool structure can make the core tube adapt to a larger diameter drill bit, thereby expanding the construction application scope of the drilling tool. In this embodiment, the drill bit uses a 150mm rib drill bit.

[0023] The open-type pumpless drill bit of the present invention has a simple and reliable structure and is easy to maintain and replace. During drilling, there is no need to use a pump to flush the borehole. Instead, the drill bit is lifted up and down and the hydrostatic pressure in the well is used to cause the circulating fluid to form a local reverse circulation at the bottom of the well, thereby achieving the purpose of removing rock powder, cooling the drill bit and improving the core recovery rate. The present invention can better cope with the geological environment of special areas, significantly improve the drilling efficiency and the core recovery rate while saving construction costs.

[0024] In another technical solution, the open-type pumpless drilling tool, the outer shell 2 includes a top cover, a side panel and a base 23, which are assembled together to form a hollow structure, the top cover is fixedly connected to the drill rod 1 and is detachably connected to the side panel, the top cover is provided with a delivery hole, which connects the drill rod 1 with the closed cavity, the diameter of the delivery hole is larger than the diameter of the first movable ball 3, and the bottom of the top cover is also provided with a first baffle 21, which is configured to close the delivery hole and is detachably connected to the top cover, a plurality of side through holes 22 are provided on the side panel at circumferential intervals, the base 23 is provided with a bottom through hole and is fixedly connected to the circulation pipe 4. The above structure allows the open-type pumpless drilling tool to be applied to different working modes. The first movable ball 3 can be a steel ball, which enters the cavity through the drill rod 1 and the delivery hole. When the first movable ball 3 is not delivered, the first baffle 21 is not installed. At this time, the drilling tool can be constructed according to the conventional pumpless drilling mode; when a special drilling mode is required, the first movable ball 3 is delivered into the inner cavity through the delivery hole, and the first baffle 21 is installed at the bottom of the top cover to close the delivery hole, so that the inner cavity enters a closed state, and drilling construction under the action of local reverse circulation at the bottom of the well can be realized.

[0025] In another technical solution, the open-type pumpless drill is provided with a flow sensor 24 at the bottom through hole of the inner cavity, which is electrically connected to an external display device. Thus, the flow rate of the fluid flowing through the first circulation hole is monitored in real time. When the drill is in the lowering state but the flow sensor shows that the flow rate at this time is 0 or lower than the set limit, the construction personnel need to check whether there is a hole blockage phenomenon at the first circulation hole to avoid affecting the smooth progress of drilling and coring.

[0026] In another technical solution, the open-type pumpless drill, the connector 5 and the circulation pipe 4, the core pipe 7, and the powder extraction pipe 6 are all coaxially sleeved by threaded matching, and the drill rod 1 is coaxially arranged with the bottom through hole of the inner cavity and the circulation pipe 4. Among them, an annular cavity with the bottom closed by the upper end face of the connector 5 is formed between the powder extraction pipe 6 and the circulation pipe 4. The coaxial arrangement structure of the above-mentioned components makes the internal force and transmission structure of the drill more stable and reasonable, which can ensure the efficient construction.

[0027] In another technical solution, in the open-type pumpless drilling tool, the lower part of the inner ring surface of the connecting head 5 is a conical surface which is narrow at the top and wide at the bottom. A plurality of auxiliary circulation devices 8 are also provided between the inner and outer ring surfaces of the connecting head 5, which are arranged at intervals along the circumference of the connecting head 5. Any auxiliary circulation device 8 includes an auxiliary hole, which is axially connected to the upper and lower end surfaces of the connecting head 5; a piston, which is arranged in the auxiliary hole and is sealingly and slidably connected thereto; and two limiting mechanisms, which are respectively arranged at both ends of the auxiliary hole, and any limiting mechanism is configured to prevent the piston from moving out of the auxiliary hole without restricting the flow of liquid including rock powder.

[0028] In the above technical solution, the lower part of the inner ring surface of the connector 5 is set as a conical surface that is narrow at the top and wide at the bottom, which can further optimize the vacuum adsorption structure, increase the contact area between the enclosed space and the circulating fluid with rock powder and core, thereby improving the adsorption strength, and then improving the circulation efficiency and core extraction rate. At the same time, the piston of the auxiliary circulation device 8 can slide up and down along the auxiliary hole under the action of pressure. When the drill tool is lifted, the piston first moves down under the action of air pressure to close the bottom end of the auxiliary hole, but in the process of continuous lifting, the circulating fluid gradually fills to the top of the core tube 7. At this time, the piston will move up in the opposite direction under the action of hydraulic pressure, and form an auxiliary air flow channel outside the original vacuum adsorption structure to ensure the stable adsorption force of the core in the core tube 7 during the core extraction process; when the drill tool is lowered, the circulating fluid with drill powder enters the powder extraction tube 6, and presses the piston from the top to reset (back to the bottom) to achieve circulation.

[0029] In another technical solution, the open-type pumpless drill bit is further provided with a plurality of second internal circulation devices between the inner and outer annular surfaces of the connecting head 5, which are arranged at intervals along the circumference of the connecting head 5, and any second internal circulation device includes a movable groove 91, which is opened at the upper end surface of the connecting head 5; a second circulation hole 92, which is opened at the lower end surface of the connecting head 5 and is connected to the bottom of the movable groove 91, and the diameter of the second circulation hole 92 is smaller than the diameter of the bottom through hole of the inner cavity; a second movable ball 93, which is arranged in the movable groove 91, and the diameter of the second movable ball 93 is larger than the diameter of the second circulation hole 92; a second baffle, which is fixed at the top opening of the movable groove 91 and is arranged to limit the displacement of the second movable ball 93.

[0030] Among them, the second baffle does not restrict the flow of liquid including rock powder. The working principle of the second internal circulation device is similar to that of the first internal circulation device. When the drill tool is lifted, the second circulation hole 92 is closed by the second movable ball 93 (the second movable ball can be a steel ball), so that the second circulation hole 92 cooperates with the core tube 7 to form a vacuum adsorption structure, and the bottom hole circulating fluid with rock powder is sucked into the core tube 7 under the action of the hydrostatic column pressure; when the drill tool is quickly lowered, the circulating fluid in the second circulation pipe 4 opens the second movable ball 93 under the action of the internal pressure to make it float, and the circulating fluid can carry the rock powder through the movable groove 91 and the second baffle into the powder extraction pipe 6, which is also used to achieve local reverse circulation at the bottom of the well. The setting position and setting height of the second internal circulation device are different from those of the first internal circulation device. On the one hand, it can play an auxiliary adsorption role in the stage of lifting the drill tool, and on the other hand, it can share the powder discharge pressure of the first circulation hole in the stage of lowering the drill tool, so as to avoid a large amount of rock powder blocking the inner circulation hole of the drill tool, resulting in the inability to discharge powder normally, affecting the drilling construction efficiency.

[0031] In another technical solution, the open-type pumpless drilling tool, the core tube 7 includes a plurality of arc-shaped segments 71, the plurality of arc-shaped segments 71 are continuously assembled along the circumferential direction to form a tubular structure, any two adjacent arc-shaped segments 71 are detachably connected, and the inner wall roughness Ra of any arc-shaped segment 71 is greater than 20 μm. Specifically, the friction between the rock powder core and the inner wall of the core tube is increased by increasing the inner wall roughness of the core tube, thereby ensuring the core recovery rate. On this basis, the core tube is set as a segmented detachable structure, which is conducive to ensuring the efficiency and convenience of subsequently removing the core from the core tube.

[0032] The present invention also provides a drilling construction method using the open-type pumpless drilling tool, comprising: S1, assembling the open-type pumpless drilling tool and performing drilling construction according to design requirements; S2. While drilling, the open pumpless drill bit is lifted and lowered in sequence to create bottom hole circulation, wherein when the drill bit is lifted upward, the circulating fluid mixed with rock powder and core in the well is sucked into the core tube 7, and when the drill bit is lowered, the circulating fluid mixed with rock powder in the core tube 7 flushes the first movable ball 3 through the circulation tube 4 and enters the inner cavity of the shell 2, and then flows into the powder extraction tube 6 through the side through hole 22 of the inner cavity, and the rock powder is precipitated in the powder extraction tube 6, and the remaining circulating fluid flows back to the well from the upper part of the powder extraction tube 6 to participate in the next circulation; When the drill tool is lifted upward, the core tube 7 forms a piston structure relative to the hole wall, and the first movable ball 3 compresses and closes the bottom through hole (first circulation hole) of the inner cavity under the action of pressure difference, so that the core tube 7 forms a vacuum suction effect on the bottom hole circulating fluid; when the drill tool is dropped, the impact force of the circulating fluid pushes open the first movable ball 3, so that it no longer closes the first circulation hole, and the circulating fluid can flow normally along the route of circulation tube 4-first circulation hole-inner cavity-side through hole 22-powder extraction tube 6 under the action of pressure. After the rock powder is precipitated in the powder extraction tube 6, the clean water in the circulating fluid floats up and flows back into the well.

[0033] S3. Repeat the steps of S2 at a set frequency to achieve powder removal drilling through bottom hole circulation.

[0034] During drilling, the drill bit is repeatedly lifted and lowered at a certain frequency to create a small circulation at the bottom of the well, which can remove rock powder and cool the drill bit. The lowering speed of the drill bit must be higher than the lifting speed to ensure the smooth circulation.

[0035] In another technical solution, the drilling construction method, in S3, during normal footage, the open-type pumpless drill bit is repeatedly lifted and lowered at a regular frequency to create a bottom hole circulation; when the footage is completed, the frequency of lifting the drill bit is reduced to gradually invalidate the circulation effect, thereby causing the rock powder to stick to the drill and the core to be blocked until the core sampling work is completed. In the above technical solution, after the coring operation is completed, the open-type pumpless drill bit is withdrawn from the well, the core tube 7 is removed to take the core, and the rock powder is poured out from the powder extraction tube 6.

[0036] The present invention has been successfully applied to a drilling project in the Luozhong area of ​​Lop Nur Salt Lake, which is 330km southwest of Ruoqiang County, 410km northeast of Hami City, and 380km north of Shanshan County. The working area is an uninhabited area of ​​the Gobi Plain salt crust landform, with an average altitude of about 800 meters; the climate in the area is dry and hot, with an annual precipitation of less than 20mm and an evaporation of more than 4000mm, which is a typical continental arid climate; the annual minimum temperature is -20℃, the maximum temperature is 45℃, and April-May and September-November are mild periods. The strata are Quaternary lake chemical salt and clastic sedimentary strata, including the W / 1 submerged brine layer and the W / 2, W / 3 and W / 3 confined brine layers. The four layers of brine are mainly composed of rock salt, calcium glauberite and gypsum with relatively developed porosity, containing a small amount of silt sand; the brine layers are relatively impermeable layers, mainly composed of dense clay or silty clay containing calcium glauberite and gypsum, with undeveloped pores.

[0037] According to the previous visits and investigations, historical construction drilling conditions and on-site construction environment, the above-mentioned open pumpless drill bits and drilling construction technology were used for the special strata in this special area, which effectively solved the problems of drilling construction difficulties and low core collection rate in the above-mentioned area.

[0038] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. An open-type pumpless drilling tool, characterized in that: include: Drill pipe; A first internal circulation device, comprising a housing, which is a hollow structure installed at the bottom of the drill pipe, and the bottom and side surfaces of the inner cavity are respectively provided with through holes communicating with the outside; a first movable ball, which is arranged in the inner cavity of the housing, and the diameter of the first movable ball is larger than the diameter of the through hole on the bottom surface of the inner cavity; A circulation pipe, which is installed at the bottom of the first internal circulation device and is sealed and connected to the bottom through hole of the inner cavity thereof; A connector, which is a sleeve structure installed at the bottom of the circulation pipe, and the upper part of the inner annular surface of the connector is sleeved with the circulation pipe; A powder extraction pipe, which is sleeved on the outside of the circulation pipe and is sleeved with the top of the outer annular surface of the connector; The core tube is installed below the connector and is sleeved with the bottom of the outer annular surface of the connector. A drill bit is mounted on the bottom of the core tube.

2. The open-type pumpless drilling tool according to claim 1, characterized in that: The outer shell includes a top cover, a side panel and a base, which are assembled together to form a hollow structure. The top cover is fixedly connected to the drill rod and detachably connected to the side panel. A delivery hole is provided on the top cover, which connects the drill rod and the closed cavity. The diameter of the delivery hole is larger than the diameter of the first movable ball. A first baffle is also provided at the bottom of the top cover, which is configured to close the delivery hole and is detachably connected to the top cover. A plurality of side through holes are provided on the side panel at circumferential intervals. A bottom through hole is provided on the base and is fixedly connected to the circulation pipe.

3. The open-type pumpless drilling tool according to claim 1, characterized in that: A flow sensor is provided at the through hole on the bottom surface of the inner cavity and is electrically connected to an external display device.

4. The open-type pumpless drilling tool according to claim 1, characterized in that: The connector is coaxially sleeved with the circulation pipe, the core pipe and the powder extraction pipe through threaded cooperation, and the drill rod is coaxially arranged with the bottom through hole of the inner cavity and the circulation pipe.

5. The open-type pumpless drilling tool according to claim 1, characterized in that: The lower part of the inner ring surface of the connector is a conical surface that is narrow at the top and wide at the bottom. A plurality of auxiliary circulation devices are also provided between the inner and outer ring surfaces of the connector, which are arranged at intervals along the circumference of the connector. Any auxiliary circulation device includes an auxiliary hole that is axially connected to the upper and lower end surfaces of the connector. A piston is arranged in the auxiliary hole and is sealingly and slidably connected thereto; two limiting mechanisms are respectively arranged at two ends of the auxiliary hole, and any limiting mechanism is configured to prevent the piston from moving out of the auxiliary hole without restricting the flow of liquid.

6. The open-type pumpless drilling tool according to claim 1, characterized in that: A plurality of second internal circulation devices are also provided between the inner and outer annular surfaces of the connector, which are arranged at intervals along the circumference of the connector, and any second internal circulation device includes a movable groove, which is opened at the upper end surface of the connector; a second circulation hole, which is opened at the lower end surface of the connector and communicates with the bottom of the movable groove, and the diameter of the second circulation hole is smaller than the diameter of the bottom through hole of the inner cavity; a second movable ball, which is arranged in the movable groove, and the diameter of the second movable ball is larger than the diameter of the second circulation hole; A second baffle is fixed at the top opening of the movable groove and is configured to limit the displacement of the second movable ball.

7. The open-type pumpless drilling tool according to claim 1, characterized in that: The core tube comprises a plurality of arc-shaped segments, which are continuously assembled along the circumferential direction to form a tubular structure, any two adjacent arc-shaped segments are detachably connected, and the inner side wall roughness Ra of any arc-shaped segment is greater than 20 μm.

8. A drilling construction method, characterized in that: The construction is carried out using the open-type pumpless drilling tool as described in claims 1 to 7, comprising: S1, assembling the open-type pumpless drilling tool and performing drilling construction according to design requirements; S2. While drilling, the open pumpless drill bit is lifted and lowered in sequence to create bottom hole circulation, wherein when the drill bit is lifted upward, the circulating fluid mixed with rock powder and core in the well is sucked into the core tube, and when the drill bit is lowered, the circulating fluid mixed with rock powder in the core tube flushes the first movable ball through the circulation tube and enters the inner cavity of the shell, and then flows into the powder extraction tube through the side through hole of the inner cavity, the rock powder is precipitated in the powder extraction tube, and the remaining circulating fluid flows back to the well from the upper part of the powder extraction tube to participate in the next circulation; S3. Repeat the steps of S2 at a set frequency to achieve powder removal drilling through bottom hole circulation.

9. The drilling construction method according to claim 8, characterized in that: In S3, during normal footage, the open pumpless drill bit is repeatedly lifted and lowered at a conventional frequency to create bottom hole circulation; at the end of the round of footage, the frequency of lifting the drill bit is reduced to gradually invalidate the circulation effect, thereby causing rock powder to stick to the drill and the core to be blocked until the core sampling work is completed.

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