Differential type self-constriction coring drilling system for hard brittle complex stratum

Abstract

The invention discloses a hard brittle complex stratum differential type self-constriction coring drilling system, which relates to the technical field of drilling, and comprises a drill rod joint, a single action mechanism, an outer pipe and a coring drill bit which are connected in sequence, and further comprises a ball clamp differential locking mechanism, an inner pipe and a clamp spring tensioning self-constriction mechanism. The ball clamp differential locking mechanism is connected with a center shaft of the single-action mechanism through the ball clamp limiting seat, the inner pipe is connected with the ball clamp mounting seat through the one-way valve mechanism, and the clamp spring tensioning self-contraction mechanism is connected to the bottom end of the inner pipe. In the coring process, the snap spring is pre-opened through the check ring, and the core entering resistance is reduced. And when the inner pipe is filled with the rock core and the ball clamp mounting seat is jacked upwards, the ball clamp mounting seat ascends, the ball enters the ball clamp limiting groove to realize locking, and meanwhile, the clamp spring is separated from the retainer ring and contracts to clamp the rock core, so that core pulling and core clamping are completed. According to the invention, the problems of easy falling, blockage and the like of the core in the hard and brittle complex stratum are solved, the core recovery rate is improved, the system stability and reliability are enhanced, and the operation process is simplified.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and more specifically to a differential self-shrinking coring drilling system for hard, brittle, and complex formations, suitable for drilling and coring operations on land, in lakes, rivers, and oceans. Background Technology

[0002] In the field of drilling, core drilling technology is one of the key means of obtaining underground geological information. In recent years, with the continuous advancement of geological surveys on land and sea in my country, core drilling operations have faced the challenge of increasingly complex geological conditions. In geological surveys and scientific research in different environments such as land, lakes, rivers, and oceans, core drilling in hard, brittle, and complex strata has always been a difficult problem in the industry.

[0003] Hard, brittle, and fractured formations typically possess high strength, low toughness, and are easily broken. When operating in such formations using existing technology, the core sample is easily broken and detached during its entry into the core tube due to erosion by drilling fluid. If the circlip is not securely engaged, the core sample can easily fall out, or even detach completely, resulting in an empty core. The accumulation of broken core samples inside the core tube creates blockages, hindering the normal entry of subsequent core samples and leading to a sharp decrease in mechanical drilling rate and per-repeated drilling footage. The risk of failed inner tube retrieval increases, and severe self-abrasion of the core within the tube not only affects core quality and efficiency but can also lead to delays and increased costs for the entire drilling operation.

[0004] Existing technologies struggle to effectively address challenges such as core blockage and core loss during coring in hard, brittle, and complex formations, hindering the improvement of core recovery rates. Therefore, developing a coring drilling system and method for hard, brittle, and complex formations that can effectively solve these problems is of significant practical importance and application value for improving core recovery rates, ensuring smooth drilling operations, and obtaining high-quality core samples. Summary of the Invention

[0005] In view of this, the present invention provides a differential self-shrinking coring drilling system for hard, brittle, and complex formations, aiming to solve the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A differential self-shrinking coring drilling system for hard, brittle, and complex formations includes a drill pipe joint, a single-action mechanism, an outer casing, and a coring bit connected in sequence; it also includes:

[0008] A ball-and-card differential locking mechanism is provided, wherein a ball-and-card limiting seat at the top of the ball-and-card differential locking mechanism is connected to the central shaft of the single-action mechanism, a ball-and-card limiting groove is provided on the lower outer wall of the ball-and-card limiting seat, a ball-and-card initial positioning shaft is connected to the bottom of the ball-and-card limiting seat, a ball-and-card mounting seat is slidably sleeved on the outer side of the ball-and-card initial positioning shaft, a through ball hole is radially provided on the top side wall of the ball-and-card mounting seat, a ball is embedded in the ball hole, one side of the ball abuts against the outer wall of the ball-and-card initial positioning shaft, and the other side is exposed outside the ball hole, a ball-and-card initial positioning sleeve is sleeved on the upper part of the ball-and-card mounting seat, an initial positioning slot corresponding to the ball is provided on the inner wall of the ball-and-card initial positioning sleeve, the initial positioning slot is used to accommodate the part of the ball exposed outside the ball hole, an external compression spring is provided between the ball-and-card initial positioning sleeve and the bottom step of the ball-and-card mounting seat, and an internal compression spring is provided inside the ball-and-card mounting seat;

[0009] The inner tube is connected to the bottom end of the ball clamp mounting base via a one-way valve mechanism;

[0010] A snap ring tensioning self-retracting mechanism is connected to the bottom end of the inner tube. The snap ring inside the snap ring tensioning self-retracting mechanism is pre-opened by a retaining ring connected to the core drill bit, and during the upward movement of the ball clamp mounting seat, the snap ring disengages from the retaining ring to achieve retraction and clamping. The action stops when the ball on the ball clamp mounting seat enters the ball clamp limiting groove of the ball clamp limiting seat.

[0011] Through the above technical solution, this invention designs a complete system including a ball-and-clamp differential locking mechanism, an inner tube, and a spring-tensioning self-retracting mechanism, achieving stable and rapid core insertion and efficient core retrieval. The cooperation of the ball-and-clamp differential locking mechanism and the spring-tensioning self-retracting mechanism effectively solves the problems of core falling out and clogging in hard, brittle, and complex formations, thus improving the core recovery rate. The system design makes the core drilling tool assembly, drilling, and core retrieval processes smoother, improving operational efficiency.

[0012] Preferably, in the aforementioned differential self-shrinking coring system for hard, brittle, and complex formations, the single-action mechanism includes a bearing housing connected to the drill pipe joint. A bearing is tightly fitted inside the bearing housing. The central shaft passes through the inner diameter of the bearing and is connected to the ball chuck limiting seat via threads. A pressure cap is pressed against the top of the bearing, and the pressure cap is pressed firmly by the drill pipe joint. The single-action mechanism, through the tight fit of the pressure cap, bearing, bearing housing, and shaft, achieves stable single-action of the inner tube, reducing torsional load losses during coring. The pressure cap, tightly fitted to the bearing and pressed by the drill pipe joint, ensures the connection strength and reliability of the entire mechanism. The connection design between the central shaft and the ball chuck limiting seat provides precise motion transmission for subsequent ball chuck differential locking.

[0013] Preferably, in the aforementioned differential self-shrinking coring system for hard, brittle, and complex formations, the top of the ball chuck limiting seat is threaded to the central shaft, and the bottom is threaded to the ball chuck initial positioning shaft. The threaded connection between the ball chuck limiting seat and the central shaft and the ball chuck initial positioning shaft simplifies the system assembly and disassembly process, facilitating maintenance and replacement. The threaded connection provides good axial stability, ensuring that the ball chuck limiting seat will not loosen under stress.

[0014] Preferably, in the aforementioned differential self-shrinking coring drilling system for hard, brittle, and complex formations, the one-way valve mechanism includes an inner tube connector, a one-way valve seat, and a one-way valve. The top end of the inner tube connector is threaded to the bottom end of the ball clamp mounting base, the bottom end of the inner tube connector is threaded to the top end of the inner tube, the one-way valve seat is threaded to the bottom of the inner tube connector, and the one-way valve is seated within the one-way valve seat. The one-way valve mechanism design ensures that the drilling fluid can only flow in one direction, preventing the core from being flushed out by the reverse-flowing drilling fluid and protecting the integrity of the core. The threaded connection design of the inner tube connector, one-way valve seat, and one-way valve makes the entire one-way valve mechanism compact and space-saving. The threaded connection facilitates quick installation and disassembly, improving operational efficiency.

[0015] Preferably, in the aforementioned differential self-shrinking coring system for hard, brittle, and complex formations, the internal compression spring is located between the bottom of the ball clamp initial positioning shaft and the top of the inner tube joint. The internal compression spring, positioned between the bottom of the ball clamp initial positioning shaft and the top of the inner tube joint, provides stable support for the ball clamp mounting base, enhancing system stability. The spring design effectively buffers the impact loads generated during coring, protecting the internal components of the mechanism.

[0016] Preferably, in the aforementioned differential self-shrinking coring system for hard, brittle, and complex formations, the snap ring tensioning self-shrinking mechanism includes an inner tube connector, a snap ring seat, a snap ring, and a retaining ring. The top of the inner tube connector is threaded to the inner tube; the snap ring seat is threaded to the bottom of the inner tube connector; the snap ring is wedged inside the snap ring seat, and its top is pressed down by the bottom end of the inner tube connector. The snap ring wedged inside the snap ring seat and pressed down by the inner tube connector ensures reliable clamping of the snap ring to the core, preventing core loss. The threaded connections between the components simplify the assembly and disassembly process and improve operational efficiency.

[0017] Preferably, in the aforementioned differential self-shrinking coring drilling system for hard, brittle, and complex formations, the retaining ring is connected to the inside of the coring bit via a thread. This threaded connection between the retaining ring and the inside of the coring bit ensures a stable connection between the snap ring tensioning self-shrinking mechanism and the coring bit, enhancing the overall system integrity. The threaded connection also allows for easy adjustment of the retaining ring's position according to actual needs, accommodating cores of different sizes.

[0018] Preferably, in the above-mentioned differential self-shrinking coring system for hard, brittle, and complex formations, the depth of the ball clamp limiting groove is the same as the depth of the initial positioning groove.

[0019] Preferably, in the aforementioned differential self-shrinking coring system for hard, brittle, and complex formations, the ball clamp limiting seat, located above the ball clamp limiting groove, has a limiting stepped surface that restricts the upward movement of the ball clamp's initial positioning sleeve. This limiting stepped surface restricts the upward distance of the ball clamp's initial positioning sleeve, preventing excessive upward movement that could lead to mechanism failure. The limiting design improves the system's reliability and ensures the normal operation of the ball clamp differential locking mechanism.

[0020] Preferably, in the above-mentioned differential self-shrinking coring drilling system for hard, brittle, and complex formations, the top of the drill pipe joint is connected to the drill pipe.

[0021] As can be seen from the above technical solution, compared with the prior art, the present invention discloses a differential self-shrinking coring drilling system for hard, brittle, and complex formations, which has the following beneficial effects:

[0022] 1. Improve core recovery rate: By combining the ball-clamp differential locking mechanism and the spring tensioning self-shrinking mechanism, the problem of cores in hard, brittle and complex strata easily falling off and getting stuck is effectively solved, realizing stable and rapid core insertion and efficient core retrieval, and significantly improving the core recovery rate.

[0023] 2. Enhanced system stability and reliability: The optimized design of various components such as the single-action mechanism, ball-clip differential locking mechanism, one-way valve mechanism, and snap ring tensioning self-retracting mechanism enables the entire system to operate stably and reliably in complex formations, reducing operation interruptions caused by component failure or loosening.

[0024] 3. Simplified operation process: The system design makes the assembly of the core drilling tool, drilling and core extraction, and other operations smoother and more convenient, improving work efficiency and reducing the workload of operators.

[0025] 4. Buffering and shock absorption: The design of internal and external compression springs can effectively buffer the impact load generated during the core extraction process, protect the internal components of the mechanism, and extend the service life of the equipment.

[0026] 5. Easy to maintain and replace: The threaded connection design between the components simplifies the system assembly and disassembly process, making maintenance and replacement easier and reducing maintenance costs. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0028] Figure 1 The attached figure is a schematic diagram of the core drilling system provided by the present invention;

[0029] Figure 2 The attached figure is a partial enlarged sectional view of the connection between the single-action mechanism and the drill pipe joint provided by the present invention;

[0030] Figure 3 The attached figure is a partial enlarged cross-sectional view of the connection between the ball differential locking mechanism and the single-action mechanism provided by the present invention;

[0031] Figure 4 The attached figure is a partial enlarged cross-sectional view of the connection between the one-way valve mechanism and the ball-clamp differential locking mechanism provided by the present invention;

[0032] Figure 5 The attached figure is a partial enlarged cross-sectional view of the connection between the snap ring tensioning self-retracting mechanism and the core drill bit provided by the present invention.

[0033] Figure 6 The attached figure is a partial enlarged cross-sectional view of the ball-cage differential locking mechanism provided by the present invention before and after differential action.

[0034] Figure 7 The attached figure is a partial enlarged cross-sectional view of the snap ring tensioning self-retracting mechanism provided by the present invention after pre-tensioning and self-retracting.

[0035] in:

[0036] 1-Drill pipe joint; 2-Single-action mechanism; 3-Outer tube; 4-Ball clasp differential locking mechanism; 5-One-way valve mechanism; 6-Inner tube; 7-Snap ring tensioning self-retracting mechanism; 8-Coring drill bit; 9-Pressure cap; 10-Bearing; 11-Bearing housing; 12-Central shaft; 13-Ball clasp limit seat; 14-Ball clasp initial positioning shaft; 15-Ball clasp initial positioning sleeve; 16-Ball; 17-Ball clasp mounting seat; 18-Outer compression spring; 19-Inner compression spring; 20-Inner tube joint; 21-One-way valve; 22-One-way valve seat; 23-Inner tube short connector; 24-Snap ring seat; 25-Snap ring; 26-Retaining ring; 27-Ball clasp limit groove; 28-Ball hole; 29-Initial positioning groove; 30-Limit step surface. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] See appendix Figure 1 and attached Figure 3 This invention discloses a differential self-shrinking coring drilling system for hard, brittle, and complex formations, comprising a drill pipe joint 1, a single-action mechanism 2, an outer tube 3, and a coring drill bit 8 connected in sequence; and further comprising:

[0039] The ball-clamp differential locking mechanism 4 has a ball-clamp limiting seat 13 at its top connected to the central shaft 12 of the single-action mechanism 2. A ball-clamp limiting groove 27 is provided on the lower outer wall of the ball-clamp limiting seat 13. A ball-clamp initial positioning shaft 14 is connected to the bottom of the ball-clamp limiting seat 13. A ball-clamp mounting seat 17 is slidably fitted on the outer side of the ball-clamp initial positioning shaft 14. A through ball hole 28 is radially provided on the top side wall of the ball-clamp mounting seat 17. A ball 16 is embedded in the ball hole 28. One side of the ball 16 is connected to... The outer wall of the ball clamp initial positioning shaft 14 abuts against the ball clamp, and the other side is exposed in the ball hole 28. The upper part of the ball clamp mounting base 17 is fitted with a ball clamp initial positioning sleeve 15. The inner wall of the ball clamp initial positioning sleeve 15 is provided with an initial positioning slot 29 corresponding to the ball 16. The initial positioning slot 29 is used to accommodate the part of the ball 16 exposed in the ball hole 28. An external compression spring 18 is provided between the ball clamp initial positioning sleeve 15 and the bottom step of the ball clamp mounting base 17. An internal compression spring 19 is provided inside the ball clamp mounting base 17.

[0040] Inner tube 6, which is connected to the bottom end of ball clamp mounting base 17 via one-way valve mechanism 5;

[0041] The snap ring tensioning self-retracting mechanism 7 is connected to the bottom end of the inner tube 6. The snap ring 25 inside the snap ring tensioning self-retracting mechanism 7 is pre-opened by the retaining ring 26 connected to the core drill bit 8, and the snap ring 25 is disengaged from the retaining ring 26 to achieve retraction and clamping during the upward movement of the ball clamp mounting seat 17. The action stops when the ball 16 on the ball clamp mounting seat 17 enters the ball clamp limiting groove 27 of the ball clamp limiting seat 13.

[0042] See appendix Figure 2 The single-action mechanism 2 mainly realizes the single-action of the inner tube during the core-taking process. It includes a bearing housing 11 connected to the drill pipe joint 1. A bearing 10 is tightly fitted on the inner side of the bearing housing 11. The central shaft 12 passes through the inner diameter of the bearing 10 and is connected to the ball clamp limit seat 13 by threads. A pressure cap 9 is pressed on the top of the bearing 10. The pressure cap 9 is pressed by the drill pipe joint 1.

[0043] To further optimize the above technical solution, the top of the ball clamp limiting seat 13 is connected to the central shaft 12 by a thread, and the bottom is connected to the ball clamp initial positioning shaft 14 by a thread.

[0044] See appendix Figure 4 The one-way valve mechanism 5 includes an inner tube connector 20, a one-way valve seat 22, and a one-way valve 21. The top end of the inner tube connector 20 is connected to the bottom end of the ball clamp mounting base 17 by a thread, the bottom end of the inner tube connector 20 is connected to the top end of the inner tube 6 by a thread, the one-way valve seat 22 is connected to the bottom of the inner tube connector 20 by a thread, and the one-way valve 21 is seated inside the one-way valve seat 22.

[0045] To further optimize the above technical solution, the internal compression spring 19 is located between the bottom of the ball clamp initial positioning shaft 14 and the top of the inner tube joint 20.

[0046] See appendix Figure 5 The snap ring tensioning self-retracting mechanism 7 includes an inner tube short connector 23, a snap ring seat 24, a snap ring 25, and a retaining ring 26; the top of the inner tube short connector 23 is connected to the inner tube 6 by a thread; the snap ring seat 24 is connected to the bottom of the inner tube short connector 23 by a thread; the snap ring 25 is wedged inside the snap ring seat 24, and its top is pressed down by the bottom end of the inner tube short connector 23.

[0047] To further optimize the above technical solution, the retaining ring 26 is internally connected to the core drill bit 8 via a thread.

[0048] To further optimize the above technical solution, the depth of the ball-mounted limiting groove 27 is the same as the depth of the initial positioning groove 29.

[0049] To further optimize the above technical solution, the ball card limiting seat 13 is located above the ball card limiting groove 27 and has a limiting step surface 30 that restricts the upward movement of the ball card initial positioning sleeve 15.

[0050] To further optimize the above technical solution, the top of drill pipe joint 1 is connected to the drill pipe.

[0051] like Figure 6 As shown, after core sampling is completed, the ball clamp mounting seat 17 is positioned a certain distance above the core until the ball 16 falls into the ball clamp limiting groove 27 of the ball clamp limiting seat 13, thereby locking the ball clamp.

[0052] like Figure 7 As shown, this embodiment can reduce the resistance of the traditional snap ring to the core during the core sampling process, and achieve stable and rapid core entry into hard, brittle and complex strata; combined with the ball-and-clamp differential locking mechanism 4, after the snap ring seat 24 is lifted a certain distance, the snap ring 25 leaves the drill bit and the retaining ring 26 retracts to clamp the core, thereby improving the core recovery rate of hard, brittle and complex strata.

[0053] The coring method of the differential self-shrinking coring drilling system for hard, brittle, and complex formations provided in this embodiment includes the following steps:

[0054] S1. First, screw the retaining ring 26 into the core drill bit 8. Then, connect the drill rod connector 1, single-action mechanism 2, outer tube 3, ball clamp differential locking mechanism 4, one-way valve mechanism 5, inner tube 6, and snap ring tensioning self-retracting mechanism 7 in sequence. Finally, wed the snap ring 26 into the retaining ring 26 through the large chamfer of the snap ring 25 to complete the connection with the core drill bit 8.

[0055] S2. After completing the core drilling tool assembly, connect it to the drill pipe and prepare for drilling to obtain cores;

[0056] S3. Start drilling for coring. During coring, pay attention to the changes in drilling footage and drill pressure. If a change in drill pressure occurs when the drilling footage of a round of coring is completed and then tends to stabilize, continue drilling for a certain distance and then stop drilling.

[0057] S4. Lift the coring tool to the ground, check if the retaining ring 25 has been lifted and locked in place of the core, remove the core, reassemble the coring tool, and prepare for the next coring operation.

[0058] The working principle of this embodiment is as follows:

[0059] Core drilling stage: such as Figure 1 and Figure 3 As shown, drill pipe joint 1 connects to the drill pipe and transmits rotational power and pressure. The bearing 10 and bearing housing 11 in the single-action mechanism 2 cause the inner tube 6 to rotate in one direction, preventing relative movement between the core and the inner tube 6 from causing blockage. The outer tube 3 protects the internal mechanism and provides support. The drill bit 8 cuts the rock formation, and the core enters the inner tube 6 under the action of drilling fluid. The retaining ring 25 of the self-contraction mechanism 7 is pre-opened by the retaining ring 26, reducing the resistance to core entry. Figure 5 As shown.

[0060] Core top and ball locking stage: such as Figure 6 As shown, when the core fills the inner tube 6 and tops the ball clamp mounting seat 17, the ball clamp mounting seat 17 moves upward. The ball 16 slides within the initial positioning slot 29 of the initial positioning sleeve 15. As the ball clamp mounting seat 17 continues to move upward, the ball 16 disengages from the initial positioning slot 29, the inner compression spring 19 compresses, and the ball 16 enters the ball clamp limiting slot 27 of the ball clamp limiting seat 13, thus locking it in place.

[0061] Core extraction and core retrieval stage: After the retaining ring 26 disengages from the retaining spring 25, it contracts under its own elasticity, tightly clamping the core. For example... Figure 7 As shown, the retaining ring 25 changes from the pre-opened state to the retracted state, completing the core extraction. Then, the drill pipe is pulled up, the core extraction is completed, and the core is removed.

[0062] Ground operation phase: such as Figure 1As shown, lift the core drilling tool to the ground and check if the retaining ring 25 has been lifted and is holding the core. After removing the core, reassemble the drilling tool according to the steps to prepare for the next core drilling operation.

[0063] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Reference can be made to the common and similar parts between the various embodiments. For the devices disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple, and the relevant parts can be referred to the method description.

[0064] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A differential self-shrinking coring drilling system for hard, brittle, and complex formations, comprising a drill pipe joint (1), a single-action mechanism (2), an outer casing (3), and a coring drill bit (8) connected in sequence; characterized in that, Also includes: A ball-clip differential locking mechanism (4) is provided. The ball-clip limiting seat (13) at the top of the ball-clip differential locking mechanism (4) is connected to the central shaft (12) of the single-action mechanism (2). A ball-clip limiting groove (27) is provided on the lower outer wall of the ball-clip limiting seat (13). A ball-clip initial positioning shaft (14) is connected to the bottom of the ball-clip limiting seat (13). A ball-clip mounting seat (17) is slidably sleeved on the outer side of the ball-clip initial positioning shaft (14). A through ball hole (28) is radially provided on the top side wall of the ball-clip mounting seat (17). A ball (16) is embedded in the ball hole (28). One side of the ball (16) is connected to the ball-clip initial positioning shaft (2). The outer wall of the ball card initial positioning shaft (14) abuts against the ball, and the other side is exposed in the ball hole (28). The upper part of the ball card mounting base (17) is fitted with a ball card initial positioning sleeve (15). The inner wall of the ball card initial positioning sleeve (15) is provided with an initial positioning slot (29) corresponding to the ball (16). The initial positioning slot (29) is used to accommodate the part of the ball (16) exposed in the ball hole (28). An external compression spring (18) is provided between the ball card initial positioning sleeve (15) and the bottom step of the ball card mounting base (17). An internal compression spring (19) is provided inside the ball card mounting base (17). Inner tube (6), the inner tube (6) is connected to the bottom end of the ball clamp mounting base (17) through a one-way valve mechanism (5); A snap ring tensioning self-retracting mechanism (7) is connected to the bottom end of the inner tube (6). The snap ring (25) inside the snap ring tensioning self-retracting mechanism (7) is pre-opened by the retaining ring (26) connected to the core drill bit (8), and the snap ring (25) is disengaged from the retaining ring (26) to achieve retraction and clamping during the upward movement of the ball clamp mounting seat (17). The action stops when the ball (16) on the ball clamp mounting seat (17) enters the ball clamp limiting groove (27) of the ball clamp limiting seat (13).

2. The differential self-shrinking coring system for hard, brittle, and complex formations according to claim 1, characterized in that, The single-action mechanism (2) includes a bearing housing (11) connected to the drill pipe joint (1). A bearing (10) is tightly fitted inside the bearing housing (11). The central shaft (12) passes through the inner diameter of the bearing (10) and is connected to the ball clamp limit seat (13) by a thread. A pressure cap (9) is pressed on the top of the bearing (10). The pressure cap (9) is pressed by the drill pipe joint (1).

3. The differential self-shrinking coring drilling system for hard, brittle, and complex formations according to claim 1, characterized in that, The top of the ball clamp limiting seat (13) is connected to the central shaft (12) by a thread, and the bottom is connected to the ball clamp initial positioning shaft (14) by a thread.

4. The differential self-shrinking coring drilling system for hard, brittle, and complex formations according to claim 1, characterized in that, The one-way valve mechanism (5) includes an inner tube connector (20), a one-way valve seat (22), and a one-way valve (21); the top end of the inner tube connector (20) is connected to the bottom end of the ball clamp mounting base (17) by a thread, the bottom end of the inner tube connector (20) is connected to the top end of the inner tube (6) by a thread, the one-way valve seat (22) is threaded to the bottom of the inner tube connector (20), and the one-way valve (21) sits inside the one-way valve seat (22).

5. The differential self-shrinking coring system for hard, brittle, and complex formations according to claim 4, characterized in that, The internal compression spring (19) is located between the bottom of the ball clamp initial positioning shaft (14) and the top of the inner tube joint (20).

6. The differential self-shrinking coring drilling system for hard, brittle, and complex formations according to claim 1, characterized in that, The snap ring tensioning self-contraction mechanism (7) includes an inner tube short connector (23), a snap ring seat (24), a snap ring (25), and a retaining ring (26); the top of the inner tube short connector (23) is connected to the inner tube (6) by a thread; the snap ring seat (24) is connected to the bottom of the inner tube short connector (23) by a thread; the snap ring (25) is wedged inside the snap ring seat (24), and its top is pressed by the bottom end of the inner tube short connector (23).

7. A differential self-shrinking coring drilling system for hard, brittle, and complex formations according to claim 6, characterized in that, The retaining ring (26) is internally connected to the core drill bit (8) via a thread.

8. The differential self-shrinking coring system for hard, brittle, and complex formations according to claim 1, characterized in that, The depth of the ball-mounted limiting groove (27) is the same as the depth of the initial positioning groove (29).

9. The differential self-shrinking coring system for hard, brittle, and complex formations according to claim 1, characterized in that, The ball card limiting seat (13) is located above the ball card limiting groove (27) and has a limiting step surface (30) that restricts the upward movement of the ball card initial positioning sleeve (15).

10. A differential self-shrinking coring drilling system for hard, brittle, and complex formations according to claim 1, characterized in that, The top of the drill pipe joint (1) is connected to the drill pipe.

Images