Semi-closed pipe type drilling device

Abstract

The utility model relates to a semi-closed pipe type drilling device which comprises a drill bit, an outer pipe and a connecting pipe head, the drill bit is detachably connected to the axial lower end of the outer pipe, and the axial upper end of the outer pipe is further detachably connected with the connecting pipe head. A semi-closed inner pipe capable of carrying out stress maintaining containing on a rock core body drilled by the drill bit is further arranged in the outer pipe, and an adjustable pressurizing assembly capable of adjustably carrying out adaptive pressurizing on a pressure maintaining liquid bag embedded in the inner pipe wall of the semi-closed inner pipe is arranged at the axial upper end of the semi-closed inner pipe. The multiple pressure maintaining liquid bags are arranged on the inner pipe wall of the semi-closed inner pipe in the annular direction at intervals. According to the utility model, stress-maintaining pressurization can be carried out on the adopted rock core body according to the stratum environment where the rock core is located so as to maintain the original state of the adopted rock core body.

Description

Technical Field

[0001] This utility model relates to the field of drilling equipment technology, and in particular to a semi-closed-tube drill bit. Background Technology

[0002] In the exploration and development of underground energy resources such as oil and natural gas and geothermal energy, as well as in the surveying of roadbeds and bridge foundations for new highways and railways, and the exploration of dam foundations for reservoirs and river embankments, rock core drilling tools are indispensable. Commonly used types of existing core drilling tools include: ordinary single-action double-tube drills, single-action double-layer semi-combined drills, single-action double-tube jet reverse circulation drills, and wireline core drilling tools. Traditional drilling and core sampling methods mainly employ diamond and cemented carbide rotary drilling, mud wall support, and single-action double-tube (including semi-combined tube) drill rods for core sampling. However, due to the complex geological structure and lithology, core extraction is generally difficult.

[0003] Core containers are used in coring tools to hold and protect core samples. Ordinary core containers are cylindrical. To facilitate core retrieval and improve core fidelity, semi-conjoined core containers with a two-lobed structure are widely used. However, existing core containers typically cannot adjust the confining pressure of the collected core samples, maintain the stress state of the core in the formation, or preserve the core's original shape. This results in the collected core samples being unusable for stratum analysis and easily leading to significant errors in stratum identification. Furthermore, existing core containers cannot pressurize the core during transfer, causing the core to slip or partially detach when the container is impacted or rapidly lifted, reducing the confining pressure and affecting the overall quality of the core, thus impacting the accuracy of subsequent core sample analysis. Utility Model Content

[0004] The purpose of this invention is to provide a semi-compound tube drill bit that can maintain the original shape of the extracted core by applying stress-holding pressure according to the geological environment of the core. This solves the problems of existing semi-compound tubes and other types of core receiving tubes, which cannot pressurize and preserve the extracted core, cannot perform stress-holding extraction and transfer of the core, cannot maintain the original shape of the core, cannot guarantee the quality of the extracted core, and are not conducive to subsequent accurate stratum identification and core testing using the core samples.

[0005] The technical solution adopted by this utility model is as follows: a semi-closed tube type drill bit, including a drill bit, an outer tube, and a connecting tube head, wherein the drill bit is detachably connected to the lower axial end of the outer tube, and the connecting tube head is detachably connected to the upper axial end of the outer tube. A semi-closed inner tube is also provided inside the outer tube to accommodate the stress of the rock core drilled by the drill bit. An adjustable pressure boosting component is provided at the upper axial end of the semi-closed inner tube to adjust the pressure-holding liquid bladder embedded in its inner tube wall. A plurality of the pressure-holding liquid bladders are arranged circumferentially at intervals on the inner tube wall of the semi-closed inner tube.

[0006] According to a preferred embodiment, the semi-circular inner tube includes a semi-circular tube body, a pressure-holding liquid bladder, an inner shell, a first limiting collar, and a second limiting collar. The two semi-circular tube bodies are joined together to form a cavity capable of accommodating the core sample. The first and second limiting collars are detachably threaded onto the top and bottom ends of the two semi-circular tube bodies, respectively, thereby defining the assembly state of the two semi-circular tube bodies. An inner shell, capable of forming a gap cavity with the inner wall of the semi-circular tube body, is connected to the inner wall of the semi-circular tube body, and multiple pressure-holding liquid bladders are embedded in the inner shell wall of the inner shell.

[0007] According to a preferred embodiment, the pressure-holding fluid bladder is connected to the gap cavity between the semi-circular tube and the inner tube by means of a shell penetrating the inner tube shell; the gap cavity between the semi-circular tube and the inner tube shell is also connected to the adjustable pressurization assembly through an insertion tube at the top of the inner tube shell.

[0008] According to a preferred embodiment, the two mating edges of the semi-circular tube are respectively provided with alignment protrusions and alignment grooves, so that the two semi-circular tubes are assembled and connected by the snap-fit ​​of the alignment protrusions and alignment grooves; the mating edges of the semi-circular tubes are also fitted with sealing strips that can fill the assembly gaps.

[0009] According to a preferred embodiment, the adjustable pressurization assembly includes a lower docking chamber, a middle valve body, and an upper liquid storage chamber, wherein the upper axial end and the lower axial end of the middle valve body are respectively connected to the upper liquid storage chamber and the lower docking chamber, so that the lower docking chamber is connected to the upper liquid storage chamber through the middle valve body inserted into its top surface.

[0010] According to a preferred embodiment, the lower docking compartment includes a first compartment shell, a docking interface, an inlet, a first sealing gasket, and a bottom deformable membrane. The docking interface, capable of simultaneously inserting two inner shell tubes and communicating with the gap cavity, is aligned with the bottom of the first compartment shell. The first sealing gasket, capable of filling the assembly gap between the first compartment shell and the top surface of the inner shell tubes, is also embedded in the bottom of the first compartment shell. The inlet, communicating with the middle valve body, is also provided at the top of the first compartment shell. A bottom deformable membrane, constituting the deformable bottom surface of the first compartment shell, is also embedded in the bottom of the first compartment shell.

[0011] According to a preferred embodiment, the intermediate valve body includes a valve shell, a flow guide channel, an elastic plug, a limiting groove, and a limiting member. The flow guide channel is vertically inserted into the valve shell, and the limiting groove communicating with the flow guide channel is also provided on the side of the valve shell. The flow guide channel is provided with an elastic plug that can be adjusted to cut it off, and the limiting member that can be laterally inserted into the limiting groove to limit the working position of the elastic plug is inserted into it.

[0012] According to a preferred embodiment, the elastic plug includes a plug body, a connecting rod, a pressure stop, a guide frame plate, and a pressure spring. The upper axial end of the connecting rod is connected to the plug body, which can selectively cut off the flow channel. The lower axial end of the connecting rod is also provided with the pressure stop, which can abut against the bottom deformable membrane. At least two guide frames are installed within the flow channel in a manner that defines the movable direction of the connecting rod. The pressure spring is also sleeved on the rod body below the guide frame plate.

[0013] According to a preferred embodiment, the limiting rod of the limiting member is movably inserted into the limiting groove, and a limiting spring is sleeved on the limiting rod. The limiting rod is also provided with a baffle that can cooperate with the cavity of the limiting groove to limit the working position of the limiting spring. A second sealing ring that can fill the insertion gap between its rod body and the limiting groove is also sleeved on the limiting rod.

[0014] According to a preferred embodiment, the bottom of the upper liquid storage tank is provided with an outlet that connects to the flow channel; the top surface of the upper liquid storage tank is fitted with a top deformable membrane capable of changing the volume of its chamber.

[0015] The beneficial effects of this utility model are:

[0016] The semi-closed inner tube can apply varying levels of pressure to the retrieved core sample according to changes in formation depth, thus achieving stress-maintaining drilling. After the core sample is retrieved and transferred to the surface, the semi-closed inner tube can be disassembled for convenient extraction of a complete core sample. The adjustable pressurization component can fill the pressure-maintaining bladder with different amounts of liquid according to formation depth, allowing the bladder to expand to varying volumes, ensuring the semi-closed inner tube maintains stress-maintaining capacity for the core sample. Furthermore, as the core sample is filled, the adjustable pressurization component can be disconnected from the pressure-maintaining bladder, ensuring that the semi-closed inner tube maintains pressure on the core sample throughout the extraction process. This preserves the core sample's original shape, ensures its quality, reduces changes in core sample condition caused by stress variations, and guarantees the accuracy of subsequent analysis of the rock strata.

[0017] The inner shell and pressure-holding liquid bladder of this application can expand and pressurize the cylindrical cavity, thereby increasing the pressure on the core sample by squeezing it under the pressure of the expanding pressure-holding liquid bladder, maintaining the stress state of the core sample, and thus ensuring the structural stability of the core sample. The pressure-holding liquid bladder can make the inner wall surface of the cavity non-smooth, thereby effectively pressurizing and maintaining stress while increasing the contact area between the core sample and the semi-enclosed inner tube. This allows the core sample to be more stably and less prone to slippage. The tight fit of the non-smooth surface can enhance the restraining strength of the pressure-holding liquid bladder on the core sample, ensuring the stability of the core sample as it is lifted and transferred to the surface with the semi-enclosed inner tube. This results in obtaining core samples with unchanged structural integrity and stratigraphic properties, avoiding the disadvantage that the confining pressure of the core sample decreases with increasing altitude during the lifting process, making it impossible to maintain the stress state it bears. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of a preferred semi-concave pipe drilling tool proposed in this utility model;

[0019] Figure 2 This is a plan view of the semi-circular tube body of a preferred semi-combined tube type drill bit proposed in this utility model;

[0020] Figure 3 This is a schematic diagram of the adjustable pressure boosting component of a preferred semi-concave pipe drill bit proposed in this utility model;

[0021] Figure 4 This is a schematic diagram of the structure of the adjustable pressure boosting component of a preferred semi-closed pipe drill bit proposed in this utility model when it is cut off.

[0022] List of reference numerals

[0023] 1: Drill bit; 2: Outer tube; 3: Semi-closed inner tube; 4: Adjustable pressure boosting component; 5: Connecting pipe head; 31: Semi-circular tube body; 32: Pressure-holding liquid bladder; 33: Inner tube shell; 34: First limiting collar; 35: Second limiting collar; 311: Alignment protrusion; 312: Alignment groove; 313: Sealing strip; 331: Inserted tube; 41: Lower docking chamber; 42: Middle section valve body; 43: Upper liquid storage chamber; 411: First chamber shell; 412: Docking interface; 413: Inlet; 41 4: First sealing gasket; 415: Bottom deformable membrane; 421: Valve housing; 422: Flow guide channel; 423: Elastic plug; 424: Limiting groove; 425: Limiting element; 4231: Plug; 4232: Connecting rod; 4233: Downward pressure baffle; 4234: Guide frame plate; 4235: Downward pressure spring; 4251: Limiting rod; 4252: Limiting spring; 4253: Baffle plate; 4254: Second sealing ring; 431: Outlet; 432: Top deformable membrane. Detailed Implementation

[0024] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the present utility model will be briefly introduced below in conjunction with the accompanying drawings and descriptions of the embodiments or the prior art. Obviously, the following description of the structure of the drawings is only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] The technical solutions provided by this utility model will be described in detail below with reference to the accompanying drawings and through embodiments. It should be noted that the descriptions of these embodiments are intended to aid in understanding this utility model, but do not constitute a limitation thereof. In some examples, because some implementation methods belong to existing or conventional technology, they are not described or are not described in detail.

[0026] Furthermore, the technical features described herein, or the steps in all the methods or processes disclosed herein, may be combined in any suitable manner in one or more embodiments, except for mutually exclusive features and / or steps. It will be readily understood by those skilled in the art that the order of steps or operations of the methods relating to the embodiments provided herein may also be altered. Any order in the drawings and embodiments is for illustrative purposes only and does not imply a requirement to follow a particular order unless explicitly stated otherwise.

[0027] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, under reasonable circumstances (without self-contradiction), include both direct and indirect connections (linkages).

[0028] The following is a detailed explanation with reference to the accompanying drawings.

[0029] Example 1

[0030] This application provides a semi-closed tube type drill bit, which includes a drill bit 1, an outer tube 2, a semi-closed inner tube 3, an adjustable pressure boosting component 4, and a connecting pipe head 5.

[0031] according to Figure 1-4 In one specific embodiment, the drill bit 1 is detachably connected to the lower axial end of the outer tube 2. A connecting pipe head 5 is also detachably connected to the upper axial end of the outer tube 2. A semi-closed inner tube 3 is also provided inside the outer tube 2 to retain the core sample drilled by the drill bit 1 under stress. An adjustable pressure boosting component 4 is provided at the upper axial end of the semi-closed inner tube 3 to adjust the pressure applied to pressure-holding liquid bladders 32 embedded in its inner tube wall. Multiple pressure-holding liquid bladders 32 are arranged circumferentially at intervals on the inner tube wall of the semi-closed inner tube 3. The semi-closed inner tube 3 can apply different magnitudes of compressive force to the extracted core sample according to changes in formation depth, thereby achieving stress-holding drilling of the core sample. The semi-closed inner tube 3 can also be disassembled as needed after the extraction operation is completed and the core sample is transferred to the surface, allowing for convenient removal of a complete core sample. The adjustable pressurization component 4 can fill the pressure-holding liquid bladder 32 with different amounts of liquid according to the formation depth, so that the pressure-holding liquid bladder 32 can expand to different sizes, thereby ensuring the stress-holding capacity of the semi-closed inner tube 3 for the core. In addition, as the core is filled, the adjustable pressurization component 4 can be disconnected from the pressure-holding liquid bladder 32 in a linked manner, so that the semi-closed inner tube 3 can always maintain the pressurized capacity of the core during the extraction process, thereby maintaining the original shape of the core, ensuring the quality of the core, reducing the changes in the state of the core caused by stress changes, and ensuring the accuracy of subsequent rock stratum property analysis of the core sample.

[0032] Preferably, the drill bit 1 is fitted onto the lower end of the outer tube 2 via a threaded connection, snap-fit ​​connection, or bolt connection. More preferably, the inner wall of the drill bit 1 has a step that supports the semi-closed inner tube 3, allowing the semi-closed inner tube 3 to maintain a movable assembly state with the drill bit 1 and outer tube 2, enabling relative rotation and separate removal after core sampling. Preferably, the connecting pipe head 5 at the top of the outer tube 2 can be connected to an impactor or drilling drive system for driving the drilling of the outer tube 2 and the drill bit 1. The outer tube 2, or the space between the outer tube 2 and the semi-closed inner tube 3, also has a fluid-conducting gap or flow channel to continuously supply drilling mud to the drill bit 1 during drilling. Furthermore, the top of the connecting pipe head 5 is connected to a drilling mud pumping system.

[0033] Preferably, the semi-circular inner tube 3 includes a semi-circular tube body 31, a pressure-holding liquid bladder 32, an inner shell 33, a first limiting collar 34, and a second limiting collar 35. Preferably, the two semi-circular tube bodies 31 are joined together in a manner that can construct a cavity to accommodate the rock core. More preferably, the first limiting collar 34 and the second limiting collar 35 are respectively detachably threaded onto the top and bottom ends of the two semi-circular tube bodies 31, thereby defining the assembly state of the two semi-circular tube bodies 31. Preferably, an inner shell 33 is connected to the inner wall surface of the semi-circular tube body 31, which can cooperate with it to form a gap cavity. Preferably, multiple pressure-holding liquid bladders 32 are embedded in the inner shell wall of the inner shell 33. Preferably, the pressure-holding liquid bladders 32 communicate with the gap cavity between the semi-circular tube body 31 and the inner shell 33 by penetrating the shell of the inner shell 33. Preferably, the gap cavity between the semi-circular tube 31 and the inner shell 33 is also connected to the adjustable pressurization component 4 through the insertion tube 331 at the top of the inner shell 33. The semi-circular tube 31 provided in this application can be disassembled in half and assembled into a cylindrical tube as needed, thereby facilitating the collection, containment, and disassembly of the core sample. The inner shell 33 and the pressure-holding liquid bladder 32 provided in this application can expand and pressurize the cylindrical cavity, thereby allowing the collected core sample to be squeezed by the expanded pressure-holding liquid bladder 32 to increase the pressure it receives, maintain the stress state of the core sample, and thus ensure the structural stability of the core sample. The pressure-holding liquid bladder 32 can transform the inner wall surface of the containing cavity into a non-smooth tube wall surface. This effectively increases the contact area between the core and the semi-closed inner tube 3 while simultaneously pressurizing and maintaining stress. This allows the core to be more stably and securely contained without slippage. The tight fit of the non-smooth surface enhances the limiting strength of the pressure-holding liquid bladder 32 on the core, ensuring the stability of the core as it is lifted and transferred to the surface. This results in obtaining core samples with unchanged structural integrity and layer properties, avoiding the drawback of the core's confining pressure decreasing with increasing altitude during lifting, which prevents it from maintaining its stress state.

[0034] Preferably, the two mating edges of the semi-circular tube 31 are respectively provided with alignment protrusions 311 and alignment grooves 312, so that the two semi-circular tubes 31 are assembled and connected by the snap-fit ​​of the alignment protrusions 311 and alignment grooves 312. Preferably, the mating edges of the semi-circular tube 31 are also fitted with sealing strips 313 that can fill the assembly gap. Preferably, the axial ends of the outer wall surface of the semi-circular tube 31 are respectively provided with external threads that can engage with the internal threads of the first limiting collar 34 and the second limiting collar 35. Preferably, the first limiting collar 34 and the second limiting collar 35 each have an embedded ring plug that converges the inner ring surface, so that when their threads rotate and are sleeved on the semi-circular tube 31, as the length of the spiral sleeve increases, the embedded ring plug pressurizes and restrains the relative position between the two semi-circular tubes 31, thereby ensuring the stability and tightness of the connection between the two. The alignment protrusion 311 and alignment groove 312 provided in this application can ensure the alignment accuracy and convenience of the two semi-circular tubes 31, and improve assembly efficiency and quality. The sealing strip 313 can fill the assembly gap, improve the tightness, and ensure the integrity and docking accuracy of the assembled tubes.

[0035] Preferably, the adjustable pressurization assembly 4 includes a lower docking chamber 41, a middle valve body 42, and an upper liquid storage chamber 43. Preferably, the upper and lower axial ends of the middle valve body 42 are respectively connected to the upper liquid storage chamber 43 and the lower docking chamber 41, so that the lower docking chamber 41 is connected to the upper liquid storage chamber 43 through the middle valve body 42 inserted into its top surface. The lower docking chamber 41 provided in this application can cooperate with the semi-closed inner tube 3 to form a tube structure with a top surface sealing, thereby facilitating more stable containment of the rock core. The middle valve body 42 provided in this application can controllably supply liquid flow to the lower docking chamber 41, so that the liquid in the upper liquid storage chamber 43 can be transported through the lower docking chamber 41 and the middle valve body 42 under the increased gravity to the pressure-holding liquid bladder 32, which expands further. This allows the pressure-holding liquid bladder 32 to squeeze the extracted rock core with a larger expansion volume, increasing the pressure on the rock core to achieve stress retention of the rock core.

[0036] Preferably, the lower docking compartment 41 includes a first compartment shell 411, a docking interface 412, an inlet 413, a first sealing gasket 414, and a bottom deformable membrane 415. Preferably, the outer side wall of the first compartment shell 411 is provided with an external thread that can be threaded into the second limiting collar 35. Preferably, the bottom of the first compartment shell 411 is aligned with a docking interface 412 that can simultaneously insert two inner tube shells 33 and communicate with the gap cavity. Preferably, the bottom of the first compartment shell 411 is also fitted with a first sealing gasket 414 that can fill the assembly gap between it and the top surface of the inner tube shell 33. Preferably, the top of the first compartment shell 411 is also provided with an inlet 413 that can communicate with the middle valve body 42. Preferably, the bottom of the first compartment shell 411 is also fitted with a bottom deformable membrane 415 that can form the deformable bottom surface of its shell. In the initial state, the bottom deformation mold 415 undergoes concave deformation under the pressure of the liquid gravity in the cavity and the limiting force of the elastic plug 423 of the middle valve body 42. As a result, it is pushed to deform during the subsequent filling of the core body, so that more liquid can be squeezed into the pressure-holding liquid bladder 32, increasing the expansion degree and pressurization intensity of the pressure-holding liquid bladder 32.

[0037] Preferably, the intermediate valve body 42 includes a valve shell 421, a flow guiding channel 422, an elastic plug 423, a limiting groove 424, and a limiting member 425. Preferably, a flow guiding channel 422 is vertically provided within the valve shell 421, so that when the valve shell 421 is connected to the lower docking chamber 41 and the upper liquid storage chamber 43, the lower axial end and the upper axial end of the flow guiding channel 422 communicate with the inlet 413 and the outlet 431 of the upper liquid storage chamber 43, respectively. More preferably, a limiting groove 424 communicating with the flow guiding channel 422 is also provided on the side of the valve shell 421. Preferably, an elastic plug 423 is provided in the flow guiding channel 422 for adjustable cutting. Preferably, a limiting member 425 capable of limiting the working position of the elastic plug 423 is inserted laterally into the limiting groove 424. Preferably, a one-way valve is provided within the flow channel 422 to limit the unidirectional delivery of liquid to the lower docking chamber 41. The elastic plug 423 provided in this application can cut off the flow channel 422 as needed to ensure the expansion state of the pressure-holding liquid bladder 32, thereby ensuring the stability of pressurization. The limiting member 425 provided in this application can lock and limit the working position of the elastic plug 423 after it rises, so that the elastic plug 423 can maintain the state of cutting off the flow channel 422 to stabilize the filling volume of the lower docking chamber 41.

[0038] Preferably, the elastic plug 423 includes a plug body 4231, a connecting rod 4232, a pressure stop 4233, a guide frame plate 4234, and a pressure spring 4235. Preferably, the upper axial end of the connecting rod 4232 is connected to a plug body 4231 capable of selectively cutting off the flow channel 422. Preferably, the lower axial end of the connecting rod 4232 is also provided with a pressure stop 4233 capable of abutting against the bottom deformable membrane 415. Preferably, at least two guide frames 4234 are installed in the flow channel 422 in a manner that defines the movable direction of the connecting rod 4232. Preferably, the rod body of the connecting rod 4232 below the guide frame plate 4234 is also fitted with a pressure spring 4235 that defines its initial working position.

[0039] Preferably, the limiting rod 4251 of the limiting member 425 is movably inserted into the limiting groove 424. Preferably, a limiting spring 4252 is sleeved on the limiting rod 4251, and a baffle 4253 is also provided on the limiting rod 4251 to limit the working position of the limiting spring 4252 by cooperating with the cavity of the limiting groove 424. Preferably, a second sealing ring 4254 is also sleeved on the limiting rod 4251 to fill the insertion gap between its rod body and the limiting groove 424.

[0040] Preferably, the bottom of the upper liquid storage tank 43 is provided with an outlet 431 that connects to the guide channel 422. Preferably, the top surface of the upper liquid storage tank 43 is fitted with a top deformable membrane 432 that can change the volume of its chamber. Preferably, the top surface of the upper liquid storage tank 43 is also provided with a liquid inlet to facilitate adding sufficient liquid to the chamber before use. Preferably, the top deformable membrane 432, the pressure-holding liquid bladder 32, and the bottom deformable membrane 415 are all made of silicone with high elasticity and deformability. Preferably, the pressurizing liquid can be directly sourced from natural water bodies, thereby avoiding potential pollution and additional costs caused by introducing other pressurizing liquids. After drilling and extraction are completed, a direct discharge depressurization operation can be performed, and the directly released water does not cause environmental pollution, eliminating the need for water recycling and treatment operations, thus improving convenience.

[0041] The working principle of this application is as follows:

[0042] When drilling for rock cores, two semi-circular tubes 31 are assembled to form a complete tube structure. Then, a first limiting collar 34 and a second limiting collar 35 are respectively fitted onto the upper and lower ends of the tube structure to limit the structural stability of the assembled tube.

[0043] The lower docking chamber 41 is inserted into the first limiting collar 34, so that the lower docking chamber 41 forms the deformable top end face of the tube structure. Then, sufficient water is injected into the upper liquid storage chamber 43.

[0044] When the semi-closed inner tube 3 and the adjustable pressurization component 4 are inserted into the outer tube 2, the increased gravity of the water body due to the increased descent depth causes the pressure-holding liquid bladder 32 to expand to a certain extent, thereby pressurizing and clamping the core material entering the tube structure. As the amount of core material filling increases, the concave bottom deformation membrane 415 is pushed by the core material and undergoes upward deformation, forcing more liquid into the pressure-holding liquid bladder 32, causing the pressure-holding liquid bladder 32 to expand more significantly, thereby increasing the clamping and compressing strength of the pressure-holding liquid bladder 32 on the core material, achieving a better stress-holding effect. In addition, during the upward deformation of the bottom deformation membrane 415, it can also push the elastic plug 423 upward, effectively cutting off the flow channel 422, so that when the semi-closed inner tube 3 and the adjustable pressurization component 4 are subsequently extracted, the pressure-holding liquid bladder 32 can maintain a stable expansion and pressurization state, thereby ensuring the integrity of the core material.

[0045] This utility model is not limited to the above-described optional embodiments. Anyone can derive other various forms of products under the guidance of this utility model. However, regardless of any changes in shape or structure, any technical solution falling within the scope of the claims of this utility model is within the protection scope of this utility model. Those skilled in the art should understand that this utility model specification and its drawings are illustrative and do not constitute a limitation on the claims. The protection scope of this utility model is defined by the claims and their equivalents. Throughout the text, features introduced by "preferred" are merely optional and should not be construed as mandatory. Therefore, the applicant reserves the right to abandon or delete relevant preferred features at any time.

Claims

1. A semi-concave-tube drill bit, comprising a drill bit (1), an outer tube (2), and a connecting tube head (5), wherein, The drill bit (1) is detachably connected to the lower axial end of the outer tube (2), and the upper axial end of the outer tube (2) is detachably connected to the connecting pipe head (5), characterized in that, Inside the outer tube (2), there is also a semi-closed inner tube (3) that can retain stress and accommodate the rock core material drilled by the drill bit (1). The upper axial end of the semi-closed inner tube (3) is provided with an adjustable pressurizing component (4) that can adjust the pressure of the pressure-holding liquid bladder (32) embedded in its inner tube wall. The plurality of pressure-holding liquid bladders (32) are arranged circumferentially at intervals on the inner tube wall of the semi-closed inner tube (3).

2. The semi-closed-tube drill bit as described in claim 1, characterized in that, The semi-circular inner tube (3) includes a semi-circular tube body (31), a pressure-holding liquid bladder (32), an inner tube shell (33), a first limiting collar (34), and a second limiting collar (35), wherein, The two semi-circular tubes (31) are joined together in a manner that can construct a cavity to accommodate the rock core, and the first limiting collar (34) and the second limiting collar (35) are respectively detachably threaded onto the top and bottom ends of the two semi-circular tubes (31), thereby limiting the assembly state of the two semi-circular tubes (31). An inner shell (33) is connected to the inner wall of the semi-circular tube (31) to form a gap cavity, and a plurality of pressure-holding liquid bladders (32) are embedded in the inner shell wall of the inner shell (33).

3. The semi-closed-tube drill bit as described in claim 2, characterized in that, The pressure-holding liquid bladder (32) is connected to the gap cavity between the semi-circular tube (31) and the inner tube shell (33) by means of the shell penetrating the inner tube shell (33); The gap cavity between the semi-circular tube (31) and the inner shell (33) is also connected to the adjustable pressurization assembly (4) through the insertion tube (331) at the top of the inner shell (33).

4. The semi-closed-tube drill bit as described in claim 3, characterized in that, The two mating edges of the semi-circular tube (31) are respectively provided with alignment protrusions (311) and alignment grooves (312), so that the two semi-circular tubes (31) are assembled and connected by the snap-fit ​​of the alignment protrusions (311) and the alignment grooves (312); the mating edges of the semi-circular tubes (31) are also fitted with sealing strips (313) that can fill the assembly gap.

5. The semi-closed-tube drill bit as described in claim 4, characterized in that, The adjustable pressurization assembly (4) includes a lower docking chamber (41), a middle valve body (42), and an upper liquid storage chamber (43), wherein, The upper and lower ends of the middle valve body (42) are respectively connected to the upper liquid storage tank (43) and the lower docking tank (41), so that the lower docking tank (41) is connected to the upper liquid storage tank (43) through the middle valve body (42) inserted on its top surface.

6. The semi-closed-tube drill bit as described in claim 5, characterized in that, The lower docking compartment (41) includes a first compartment shell (411), a docking interface (412), an inlet (413), a first sealing gasket (414), and a bottom deformable membrane (415), wherein, The bottom of the first housing (411) is connected to the interface (412) which is capable of inserting two inner shells (33) at the same time and communicating with the cavity of the gap partition. The bottom of the first housing (411) is also fitted with the first sealing gasket (414) which is capable of filling the assembly gap between it and the top surface of the inner shell (33). The top of the first chamber shell (411) is also provided with the inlet (413) that can communicate with the middle section valve body (42); and the bottom of the first chamber shell (411) is also fitted with a bottom deformable membrane (415) that can form the deformable bottom surface of its shell.

7. The semi-closed-tube drill bit as described in claim 6, characterized in that, The middle section valve body (42) includes a valve shell (421), a flow guide channel (422), an elastic plug (423), a limiting groove (424), and a limiting element (425), wherein, The flow guide channel (422) is vertically provided inside the valve housing (421), and the limiting groove (424) communicating with the flow guide channel (422) is also provided on the side of the valve housing (421); The flow channel (422) is provided with an elastic plug (423) that can be adjusted to cut it off, and a limiting member (425) that can limit the working position of the elastic plug (423) is inserted into the limiting groove (424) laterally.

8. The semi-closed-tube drill bit as described in claim 7, characterized in that, The elastic plug (423) includes a plug body (4231), a connecting rod (4232), a downward pressure stop (4233), a guide frame plate (4234), and a downward pressure spring (4235), wherein, The upper axial end of the connecting rod (4232) is connected to the plug (4231) which can selectively cut off the flow channel (422), and the lower axial end of the connecting rod (4232) is also provided with the downward pressure stop (4233) which can abut against the bottom deformable membrane (415). At least two of the guide frames (4234) are installed in the flow channel (422) in a manner that defines the movable direction of the connecting rod (4232); the connecting rod (4232) is also fitted with the compression spring (4235) on the rod body below the guide frame (4234).

9. The semi-closed-tube drill bit as described in claim 8, characterized in that, The limiting rod (4251) of the limiting member (425) is movably inserted into the limiting groove (424), and a limiting spring (4252) is sleeved on the limiting rod (4251). A baffle (4253) is also provided on the limiting rod (4251) to limit the working position of the limiting spring (4252) in cooperation with the cavity of the limiting groove (424). The limiting rod (4251) is also fitted with a second sealing ring (4254) that can fill the insertion gap between its rod body and the limiting groove (424).

10. The semi-closed-tube drill bit as described in claim 9, characterized in that, The bottom of the upper liquid storage tank (43) is provided with an outlet (431) that connects with the flow channel (422); the top surface of the upper liquid storage tank (43) is fitted with a top deformable membrane (432) that can change the volume of its chamber.

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