Thin wall upset drill pipe for complex formations

Abstract

This utility model discloses a thin-walled, thickened wireline coring drill rod for complex strata, relating to the field of drill rod technology. It includes a drill rod body comprising an outer tube, with an inner tube slidably connected within the cavity of the outer tube. A first groove is formed on the top of the inner wall of the outer tube, engaging with a borehole elastic retaining ring. A first limiting groove is formed on the top of the inner tube, engaging with the bottom of the borehole elastic retaining ring. An upper connector is threaded to the top of the outer tube, and a lower connector is threaded to the bottom of the outer tube. The drill rod body provided by this utility model reduces wear on the inner and outer tube walls while preventing pressure loss leading to reverse circulation failure. This solves the problems of high-pressure gas escape during drilling causing reverse circulation failure and borehole wall collapse, as well as severe friction and short lifespan of existing wireline coring drill rods.

Description

Technical Field

[0001] This utility model relates to the field of drill pipe technology, specifically to a thin-walled thickened wireline coring drill pipe for complex formations. Background Technology

[0002] Wireline coring drill pipe is a specialized pipe used in geological drilling. It allows for the direct extraction of rock cores from the bottom of the hole via an internal wireline system, eliminating the need to remove the entire drill pipe. This significantly improves core extraction efficiency and drilling safety.

[0003] A search revealed the following publication (announcement) number: CN113638700A, entitled: "A High-Performance Thin-Walled Wireline Core Drill Rod for Deep Holes," comprising a rod body. The rod body is reinforced at both ends through integrated internal and external upsetting, achieving a structural improvement that meets the requirements of wireline core drilling technology and the drilling intensity requirement of 5000 meters. By controlling the length difference between the male and female threads, the axial load borne by the threads at both ends of the male and female joints is made equivalent. The outer surface of the joint adopts an octagonal structure to reduce damage to the outer surface of the drill rod joint during the uncoupling process.

[0004] The above technical solution has the following shortcomings;

[0005] In actual use of the above-mentioned scheme in wireline coring drilling operations, high-pressure gas cannot return from the inner drill pipe along the preset path. Instead, it flows into the annular space formed by the outer drill pipe and the borehole wall through the gap between the drill bit's ball teeth, and then escapes along the gap in this space. This process causes a sudden drop in system pressure, making it impossible to establish effective reverse circulation and directly weakening the reverse circulation driving force. This not only obstructs the upward return channel of rock cuttings, resulting in a significant decrease in drilling efficiency, but also damages the stability of the borehole wall due to the pressure imbalance inside the hole, which can easily lead to safety accidents such as borehole wall collapse. This seriously affects the continuity and safety of drilling operations. Furthermore, during the drilling process, the outer and inner tubes of the wireline coring drill pipe are in a state of dynamic relative motion, and the contact surface between the two lacks an effective lubrication structure, resulting in severe friction. Long-term high-intensity friction not only accelerates the wear of the inner and outer tube walls, shortens the service life of the drill pipe, but also increases the equipment replacement cost. Utility Model Content

[0006] In view of the problems existing in the current thin-walled thickened wireline coring drill rod for complex strata, this utility model is proposed.

[0007] Therefore, the purpose of this utility model is to provide a thin-walled thickened wireline coring drill rod for complex strata, which solves the problems of high-pressure gas escape during drilling leading to reverse circulation failure, borehole wall collapse, severe friction between inner and outer tubes, and short service life of existing wireline coring drill rods.

[0008] To achieve the above objectives, this utility model provides the following technical solution:

[0009] A thin-walled thickened wireline coring drill pipe for complex formations includes a drill pipe body, the drill pipe body including an outer tube, an inner tube slidably connected to the cavity of the outer tube, a first groove is formed on the top of the inner side wall of the outer tube and a hole elastic retaining ring is engaged therewith, a first limiting groove is formed on the top of the inner tube and the first limiting groove is engaged with the bottom of the hole elastic retaining ring, an upper connector is threaded to the top of the outer tube and a lower connector is threaded to the bottom of the outer tube;

[0010] The outer tube is provided with sealing mechanisms between its two ends and the lower and upper connectors, respectively. A stepped sealing ring assembly is fixedly connected between the bottom of the elastic retaining ring and the outer wall of the inner tube. The inner walls of both ends of the outer tube are provided with guide sliding mechanisms that are slidably connected to the outer wall of the inner tube.

[0011] Preferably, the sealing mechanism includes an upper sealing ring, a lower sealing ring, and a sealing groove. One end of the upper connector and the lower connector is fixedly connected to an upper sealing ring. The bottom of the inner wall of the outer tube and the top of the elastic retaining ring of the hole are both engaged with lower sealing rings. Sealing grooves are opened on the surfaces of the upper and lower sealing rings at both ends, and the upper sealing rings at both ends are engaged with the corresponding lower sealing rings.

[0012] Preferably, the guide sliding mechanism includes a support ring, a guide protrusion, and a ball bearing. The inner walls of both ends of the outer tube are fixedly connected to the support ring, and the inner walls of the support ring at both ends are fixedly connected to multiple guide protrusions. Each guide protrusion has a ball bearing rotatably connected inside its cavity.

[0013] Preferably, the outer tube includes a thin-walled main pipe end, and thickened connecting ends are fixedly connected to both ends of the thin-walled main pipe end. Both the thin-walled main pipe end and the thickened connecting ends include a high-strength alloy outer layer, and a wear-resistant and corrosion-resistant inner layer is fixedly connected inside the cavity of the high-strength alloy outer layer.

[0014] Preferably, the inner tube includes a tough protective outer layer, and a smooth inner lining is fixedly connected inside the cavity of the tough protective outer layer.

[0015] Furthermore, the stepped sealing ring assembly includes a stepped lower sealing ring, which is fixedly connected to the top wall of the inner tube. A stepped upper sealing ring is snapped onto the top of the stepped lower sealing ring, and the top of the stepped upper sealing ring is snapped onto the bottom of the elastic retaining ring for the hole.

[0016] Preferably, each of the balls has a molybdenum disulfide coating on its surface.

[0017] The technical effects and advantages provided by this utility model in the above technical solution are as follows:

[0018] 1. This utility model utilizes a sealing mechanism set between the outer tube and the joint to form a double seal through an upper sealing ring, a lower sealing ring, and a sealing groove. The stepped sealing ring assembly strengthens the seal between the elastic retaining ring of the hole and the inner tube, effectively preventing high-pressure gas from escaping, avoiding reverse circulation failure and hole wall collapse, and ensuring the stability of drilling in complex formations.

[0019] 2. This utility model utilizes the ball bearings set in the guide sliding mechanism to convert sliding friction into rolling friction. The molybdenum disulfide coating on its surface further reduces frictional resistance. The wear-resistant and corrosion-resistant inner layer of the outer tube and the tough protective outer layer of the inner tube reduce wear and corrosion, solving the problems of severe friction and short life of the inner and outer tubes, and is suitable for long-term drilling needs.

[0020] 3. This utility model utilizes a lightweight design of a thin-walled main pipe end set in the outer tube and a thickened connecting end to enhance connection strength. A high-strength alloy outer layer ensures load-bearing capacity, while a smooth inner lining layer set in the inner tube reduces core friction and prevents core breakage. At the same time, a tough protective outer layer resists impact, balancing drill pipe durability and core integrity. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0022] Figure 1 This is a three-dimensional structural diagram of the present invention;

[0023] Figure 2 This is a schematic diagram of the upper half of the cross-section of this utility model;

[0024] Figure 3 This is a lower half sectional view of the present invention;

[0025] Figure 4 This is a top cross-sectional view of the present invention;

[0026] Figure 5 For the present utility model Figure 2 Enlarged schematic diagram of part A.

[0027] Explanation of reference numerals in the attached figures:

[0028] 1. Drill pipe body; 2. Outer tube; 3. Inner tube; 4. First groove; 5. Hole elastic retaining ring; 6. First limiting groove; 7. Upper connector; 8. Lower connector; 9. Stepped sealing ring assembly; 10. Upper sealing ring; 11. Lower sealing ring; 12. Sealing groove; 13. Support ring; 14. Guide protrusion; 15. Ball bearing; 16. Thin-walled main pipe end; 17. Thickened connecting end; 18. High-strength alloy outer layer; 19. Wear-resistant and corrosion-resistant inner layer; 20. Tough protective outer layer; 21. Smooth inner lining layer; 22. Stepped lower sealing ring; 23. Stepped upper sealing ring. Detailed Implementation

[0029] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0030] This utility model discloses a thin-walled thickened wireline coring drill rod for complex strata.

[0031] This utility model provides, for example Figures 1-5 The thin-walled thickened wireline coring drill rod shown is used in complex formations. It includes a drill rod body 1, an outer tube 2, an inner tube 3 slidably connected to the cavity of the outer tube 2, a first groove 4 is opened on the top of the inner side wall of the outer tube 2 and a hole elastic retaining ring 5 is engaged, a first limiting groove 6 is opened on the top of the inner tube 3 and is engaged with the bottom of the hole elastic retaining ring 5, an upper connector 7 is threaded to the top of the outer tube 2, and a lower connector 8 is threaded to the bottom of the outer tube 2.

[0032] Sealing mechanisms are provided between the two ends of the outer tube 2 and the lower connector 8 and the upper connector 7, respectively. A stepped sealing ring assembly 9 is fixedly connected between the bottom of the orifice elastic retainer 5 and the outer wall of the inner tube 3. The inner walls of both ends of the outer tube 2 are provided with guide sliding mechanisms that slide with the outer tube wall of the inner tube 3. The drill rod body 1 is designed as an inner and outer tube structure to realize the wireline coring function, which is suitable for drilling in complex formations. The outer tube 2 provides external protection and support, and the inner tube 3 is used to hold the core. The sliding connection between the two facilitates the coring operation. The first retaining groove 4 cooperates with the orifice elastic retainer 5 to limit the axial displacement of the inner tube 3 and prevent the inner tube 3 from falling out of the cavity of the outer tube 2. The first limiting groove 6 further strengthens the connection between the orifice elastic retainer 5 and the inner tube 2. The inner tube 3 is designed to ensure a stable connection. The upper connector 7 and lower connector 8 are used to connect the drill rod body 1 to other drilling tools. The threaded connection ensures a firm connection and easy disassembly. The sealing mechanism blocks the gap between the outer tube 2 and the connector to prevent high-pressure gas from escaping, thus avoiding reverse circulation failure and borehole wall collapse. The stepped sealing ring assembly 9 enhances the sealing between the borehole elastic retaining ring 5 and the inner tube 3, further preventing gas leakage. The guide sliding mechanism reduces the frictional resistance when the inner tube 3 and outer tube 2 slide, reducing tube wall wear and extending the service life of the drill rod. This solves the problems of high-pressure gas escaping during drilling of existing wireline coring drill rods, which leads to reverse circulation failure, borehole wall collapse, severe friction between the inner and outer tubes, and short service life.

[0033] To enhance the sealing between the outer pipe and the joint, and to prevent the escape of high-pressure gas, such as Figure 2 and 3 As shown, the sealing mechanism includes an upper sealing ring 10, a lower sealing ring 11, and a sealing groove 12. One end of the upper connector 7 and the lower connector 8 is fixedly connected to the upper sealing ring 10. The bottom of the inner wall of the outer tube 2 and the top of the elastic retaining ring 5 for the hole are both clamped to the lower sealing ring 11. The surfaces of the upper sealing ring 10 and the lower sealing ring 11 at both ends are provided with sealing grooves 12. The upper sealing ring 10 at both ends is clamped to the corresponding lower sealing ring 11. The upper sealing ring 10 and the lower sealing ring 11 are fixed to the connector and the outer tube respectively, and a double sealing structure is formed by their mutual clamping. The sealing groove 12 increases the contact area of ​​the sealing ring, improves the sealing effect, effectively prevents high-pressure gas from escaping from the connection gap between the outer tube and the connector, ensures the normal operation of reverse circulation drilling, and avoids the collapse of the hole wall.

[0034] To reduce sliding friction between the inner and outer tubes and improve sliding smoothness, such as Figures 2-4As shown, the guide sliding mechanism includes a support ring 13, guide protrusions 14, and balls 15. The inner walls of both ends of the outer tube 2 are fixedly connected to the support ring 13, and multiple guide protrusions 14 are fixedly connected to the inner walls of the support rings 13 at both ends. Each guide protrusion 14 has a ball 15 rotatably connected inside its cavity. The support ring 13 provides a mounting base for the guide protrusions 14, ensuring the stability of the guide structure. The guide protrusions 14 restrict the sliding direction of the inner tube 3, preventing the inner and outer tubes from deviating. The balls 15 convert the sliding friction between the inner tube 3 and the outer tube 2 into rolling friction, significantly reducing frictional resistance, reducing tube wall wear, and extending the service life of the drill pipe.

[0035] To enhance the structural strength and corrosion resistance of the outer pipe and adapt it to complex geological formations, such as... Figures 1-4 As shown, the outer tube 2 includes a thin-walled main pipe end 16, and thickened connecting ends 17 are fixedly connected to both ends of the thin-walled main pipe end 16. Both the thin-walled main pipe end 16 and the thickened connecting ends 17 include a high-strength alloy outer layer 18. A wear-resistant and corrosion-resistant inner layer 19 is fixedly connected inside the cavity of the high-strength alloy outer layer 18. The thin-walled main pipe end 16 reduces the overall weight of the drill pipe while ensuring strength. The thickened connecting ends 17 enhance the structural strength of the connection between the two ends of the outer tube and the joint, preventing the connection from breaking. The high-strength alloy outer layer 18 ensures the bearing capacity of the outer tube foundation. The wear-resistant and corrosion-resistant inner layer 19 resists the erosion and friction of corrosive media in complex formations, extending the service life of the outer tube.

[0036] To improve the toughness and smoothness of the inner tube and protect the integrity of the core, such as Figure 4 As shown, the inner tube 3 includes a tough protective outer layer 20, and a smooth inner lining 21 is fixedly connected inside the cavity of the tough protective outer layer 20. The tough protective outer layer 20 enhances the impact resistance of the inner tube and avoids damage to the inner tube due to vibration or collision during drilling in complex formations. The smooth inner lining 21 reduces the friction between the core and the inner wall of the inner tube, prevents the core from breaking during the core extraction process, and facilitates the extraction of the core, ensuring the integrity of the core.

[0037] To further enhance the sealing performance between the flexible retaining ring and the inner tube, such as Figure 2 and 4 As shown, the stepped sealing ring assembly 9 includes a stepped lower sealing ring 22, which is fixedly connected to the top wall of the inner tube 3. A stepped upper sealing ring 23 is snapped onto the top of the stepped lower sealing ring 22, and the top of the stepped upper sealing ring 23 is snapped onto the bottom of the orifice elastic retaining ring 5. The stepped lower sealing ring 22 and the stepped upper sealing ring 23 are interlocked through the stepped structure to form a stepped seal, which increases the sealing contact area, improves the sealing reliability, effectively prevents high-pressure gas from escaping from the gap between the orifice elastic retaining ring and the inner tube, and ensures the reverse circulation effect.

[0038] To improve the wear resistance and lubrication of the balls and reduce frictional loss, such as Figures 2-4 As shown, each ball 15 has a molybdenum disulfide coating on its surface. The molybdenum disulfide coating has excellent lubricity and wear resistance, which can further reduce the frictional resistance between the ball and the outer wall of the inner tube, reduce ball wear, extend the service life of the guide sliding mechanism, and ensure smooth sliding of the inner and outer tubes for a long time.

[0039] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A thin-walled, thickened wireline coring drill pipe for complex formations, comprising a drill pipe body (1), characterized in that, The drill pipe body (1) includes an outer tube (2), an inner tube (3) is slidably connected inside the cavity of the outer tube (2), a first slot (4) is opened on the top of the inner side wall of the outer tube (2), and a hole elastic retaining ring (5) is engaged thereon, a first limiting slot (6) is opened on the top of the inner tube (3), the first limiting slot (6) is engaged with the bottom of the hole elastic retaining ring (5), an upper connector (7) is threaded to the top of the outer tube (2), and a lower connector (8) is threaded to the bottom of the outer tube (2); The outer tube (2) is provided with sealing mechanisms between its two ends and the lower connector (8) and the upper connector (7), respectively. The bottom of the elastic retaining ring (5) for the hole is fixedly connected to the outer wall of the inner tube (3) with a stepped sealing ring assembly (9). The inner walls of both ends of the outer tube (2) are provided with guide sliding mechanisms that are slidably connected to the outer wall of the inner tube (3).

2. The thin-walled thickened wireline coring drill pipe for complex strata according to claim 1, characterized in that, The sealing mechanism includes an upper sealing ring (10), a lower sealing ring (11), and a sealing groove (12). One end of the upper connector (7) and the lower connector (8) is fixedly connected to the upper sealing ring (10). The bottom of the inner wall of the outer tube (2) and the top of the hole are both secured with the lower sealing ring (11). The surfaces of the upper sealing ring (10) and the lower sealing ring (11) at both ends are provided with sealing grooves (12). The upper sealing ring (10) at both ends is engaged with the corresponding lower sealing ring (11).

3. A thin-walled, thickened wireline coring drill pipe for complex formations according to claim 1, characterized in that, The guide sliding mechanism includes a support ring (13), a guide protrusion (14), and a ball (15). The inner walls of both ends of the outer tube (2) are fixedly connected with support rings (13), and the inner walls of the support rings (13) at both ends are fixedly connected with multiple guide protrusions (14). Each guide protrusion (14) has a ball (15) rotatably connected in its cavity.

4. A thin-walled, thickened wireline coring drill pipe for complex formations according to claim 1, characterized in that, The outer tube (2) includes a thin-walled main pipe end (16), and thickened connecting ends (17) are fixedly connected to both ends of the thin-walled main pipe end (16). Both the thin-walled main pipe end (16) and the thickened connecting ends (17) include a high-strength alloy outer layer (18), and a wear-resistant and corrosion-resistant inner layer (19) is fixedly connected inside the cavity of the high-strength alloy outer layer (18).

5. A thin-walled, thickened wireline coring drill pipe for complex formations according to claim 1, characterized in that, The inner tube (3) includes a tough protective outer layer (20), and a smooth inner lining (21) is fixedly connected inside the cavity of the tough protective outer layer (20).

6. A thin-walled, thickened wireline coring drill pipe for complex formations according to claim 1, characterized in that, The stepped sealing ring assembly (9) includes a stepped lower sealing ring (22), which is fixedly connected to the top wall of the inner tube (3). A stepped upper sealing ring (23) is snapped onto the top of the stepped lower sealing ring (22), and the top of the stepped upper sealing ring (23) is snapped onto the bottom of the hole elastic retaining ring (5).

7. A thin-walled, thickened wireline coring drill pipe for complex formations according to claim 3, characterized in that, Each of the ball bearings (15) has a molybdenum disulfide coating on its surface.

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