High-strength non-magnetic drill collar

Abstract

The application discloses high-strength non-magnetic drill collar, belongs to the technical field of oil drilling drilling tools, including: drill collar rod, one end of the drill collar rod is provided with a buffer head; drill collar head, the drill collar head is threadedly connected on one side of the buffer head, a T-shaped buffer groove is arranged in the buffer head, and a buffer disc spring is arranged in the T-shaped buffer groove; a connecting end is arranged on one side of the buffer head; a threaded connection groove is arranged on the inner circular wall surface of the drill collar rod; by arranging the buffer disc spring, injecting non-magnetic inert gas into the T-shaped buffer groove through the gas injection nozzle on the outside of the drill collar head, and buffering through the buffer disc spring and the buffer gas, the high-strength non-magnetic drill collar can absorb large impact load and high-frequency small impact load, effectively reduce the damage of impact stress to the drill collar rod, the buffer head and the connecting position, avoid the deformation of the drill collar body and the connection failure, and improve the applicability of the drill collar in deep high-impact drilling scenes.

Description

Technical Field

[0001] This invention relates to the field of oil drilling tools technology, specifically a high-strength non-magnetic drill collar. Background Technology

[0002] In oil, gas, and geothermal drilling operations, measurement while drilling (MWD / LWD) technology is the core means to achieve directional drilling and precise well control. High-strength non-magnetic drill collars, as key load-bearing and shielding components of the MWD system, directly determine drilling efficiency, measurement accuracy, and downhole operational safety. Non-magnetic drill collars must simultaneously meet two core requirements: first, they must possess extremely low magnetic permeability to avoid interference with geomagnetic signals from their own magnetic field, ensuring the accuracy of data from MWD instruments (such as magnetometers); second, they must possess extremely high mechanical strength, impact resistance, and corrosion resistance to withstand the enormous axial pressure, torsional force, and impact loads during deep and ultra-deep drilling processes, as well as the long-term corrosion from harsh downhole environments such as high temperature, high pressure, high sulfur (H2S), and high salinity.

[0003] According to Chinese Patent Application No. CN202320542817.6, a high-strength non-magnetic drill collar is disclosed, comprising a drill collar body, an installation mechanism at the top of the drill collar body, and a connecting plate welded to the top of the installation mechanism; the installation mechanism includes an installation plate welded to the bottom of the connecting plate, an installation groove inside the installation plate, a positioning post welded to the inner top of the installation plate, a positioning hole matching the positioning post inside the drill collar body, a locking screw penetrating inside the installation plate, the end of the locking screw extending into the interior of the drill collar body, and a threaded hole matching the locking screw on the outer wall of the drill collar body. This high-strength non-magnetic drill collar, through its installation mechanism, allows operators to more easily install the drill collar and facilitates subsequent maintenance and replacement, effectively improving operator convenience.

[0004] In actual use, the drill collars of the aforementioned devices are subjected to severe impact loads and alternating stresses transmitted by the drill bit, which may lead to connection failures in the drill collar body and connecting parts. Summary of the Invention

[0005] The purpose of this invention is to provide a high-strength non-magnetic drill collar to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: A high-strength non-magnetic drill collar, comprising: A drill collar rod, one end of which is equipped with a buffer head; A drill collar, which is threaded to one side of a buffer head, and the buffer head has a T-shaped buffer groove inside, and a buffer disc spring is installed inside the T-shaped buffer groove; A connecting end, wherein the connecting end is disposed on one side of the buffer head; A threaded connection groove is provided on the inner circular wall surface of the drill collar rod, and the threaded connection groove is threadedly connected to the connection end; A buffer component is disposed outside the drill collar for buffering the drill collar.

[0007] Preferably, the buffer component includes: An air injection hole is provided on the outer circular wall surface of the drill collar. The air injection nozzle is fixedly installed inside the air injection hole; The T-shaped buffer groove is filled with buffer gas; A connector is disposed on the outer circular wall surface of the buffer head and is used to connect the buffer head to the drill collar rod.

[0008] Preferably, the connector includes: Two connecting blocks are fixedly installed on the outer circular wall surface of the drill collar rod; Two connecting brackets are fixedly installed on the outer circular wall surface of the buffer head; A pressing block, wherein the pressing block is disposed inside the connecting frame; Two movable rods are fixedly installed on one side of the pressing block; Two movable holes are provided on one side of the connecting frame, and the movable rod is movably fitted together with the movable holes; A compression spring is disposed outside the movable rod.

[0009] Preferably, a cover plate is provided on one side of the connecting frame, and the cover plate is connected to the connecting frame by a hinge.

[0010] Preferably, the drill collar rod is provided with a connecting sleeve inside, and the connecting sleeve has a plurality of reinforcing holes inside, and the reinforcing holes are provided with reinforcing ribs inside.

[0011] Preferably, the outer circular wall of the drill collar rod has two connecting holes, and the connecting holes are threaded with connecting bolts.

[0012] Preferably, the connecting sleeve has a metal reinforcing mesh inside, and the outer layer of the metal reinforcing mesh is provided with a high molecular weight polyethylene protective outer layer.

[0013] Preferably, a sealing ring is provided at the connection of the drill collar.

[0014] Preferably, the connection points between the connecting sleeve and the drill collar rod, the buffer head, and the drill collar head are all coated with non-magnetic sealant.

[0015] Preferably, the drill collar rod, buffer head, drill collar head, buffer component, and connector are all made of non-magnetic materials.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. By installing a buffer disc spring, non-magnetic inert gas is injected into the T-shaped buffer groove through an air injection nozzle outside the drill collar. After injection, the air injection nozzle is sealed, and the sealing ring at the connection point achieves a seal between the drill collar and the buffer head, preventing drilling fluid from seeping into the T-shaped buffer groove and avoiding buffer gas leakage. During drilling operations, the drill collar bears the axial impact load and alternating stress transmitted by the drill bit. At this time, the impact load first acts on the drill collar and is then transmitted to the buffer disc spring inside the buffer head. The buffer disc spring undergoes elastic deformation, initially absorbing the impact energy and mitigating the impact load on the drill collar rod. The buffer gas in the T-shaped buffer groove is compressed, and the gas pressure increases. Utilizing the compressibility of the gas, it further absorbs high-frequency, small-amplitude impact loads, forming a synergistic buffering effect with the buffer disc spring. This prevents the impact load from being concentrated on the connection part and the drill collar rod body. Through the synergistic buffering of the buffer disc spring and buffer gas, it absorbs large-amplitude impact loads and high-frequency, small-amplitude impact loads, effectively reducing the impact stress damage to the drill collar rod, buffer head, and connection parts, preventing drill collar body deformation and connection failure, and improving the applicability of the drill collar in deep, high-impact drilling scenarios.

[0017] 2. By setting up connecting frames, with each of the two connecting frames corresponding to the connecting block, the pressure block is squeezed by the connecting block and moves into the connecting frame, causing the movable rod to slide along the movable hole. At the same time, the pressure spring is compressed, and the pressure spring generates a reverse elastic force, pushing the pressure block to press tightly against the connecting block, realizing the elastic pre-tightening limit of the buffer head and drill collar rod, forming a double fixation with the threaded connection; finally, the cover plate is closed by the hinge to protect the pressure block, movable rod, and pressure spring inside the connecting frame, improving the anti-loosening and anti-wear capabilities of the connection parts, avoiding the failure of the buffer components and the corrosion of the components, and extending the service life of the drill collar downhole. Attached Figure Description

[0018] Figure 1 A schematic diagram of the three-dimensional structure of a high-strength non-magnetic drill collar; Figure 2 A schematic cross-sectional view of the drill collar rod in a high-strength non-magnetic drill collar; Figure 3 A schematic diagram of the connecting frame structure in a high-strength non-magnetic drill collar; Figure 4 A schematic diagram of the cover plate structure in a high-strength non-magnetic drill collar; Figure 5 for Figure 2 Enlarged schematic diagram of a local structure at point A; Figure 6 A schematic diagram of the drill collar head structure in a high-strength non-magnetic drill collar; Figure 7 This is a schematic diagram of the connecting sleeve structure in a high-strength non-magnetic drill collar.

[0019] In the diagram: 1. Drill collar rod; 2. Buffer head; 3. Drill collar head; 4. Connecting end; 5. Threaded connecting groove; 6. T-shaped buffer groove; 7. Buffer disc spring; 8. Connecting block; 9. Connecting frame; 10. Pressing block; 11. Movable hole; 12. Movable rod; 13. Pressing spring; 14. Cover plate; 15. Hinge; 16. Connecting hole; 17. Connecting bolt; 18. Connecting sleeve; 19. Reinforcing hole; 20. Reinforcing rib; 21. Metal reinforcing mesh; 22. High molecular weight polyethylene protective outer layer; 23. Air injection hole; 24. Air injection nozzle; 25. Sealing ring. Detailed Implementation

[0020] Please see Figures 1 to 7 In this embodiment of the invention, a high-strength non-magnetic drill collar includes: a drill collar rod 1, with a buffer head 2 at one end; a drill collar head 3, threadedly connected to one side of the buffer head 2, the buffer head 2 having a T-shaped buffer groove 6 inside, and a buffer disc spring 7 inside the T-shaped buffer groove 6; a connecting end 4, located on one side of the buffer head 2; and a threaded connecting groove 5, located on the inner circular wall of the drill collar rod 1, threadedly connected to the connecting end 4. Connected together; a buffer component, which is set on the outside of the drill collar 3 for buffering the drill collar 3, the buffer component includes: an air injection hole 23, which is opened on the outer circular wall of the drill collar 3; an air injection nozzle 24, which is fixedly installed inside the air injection hole 23; buffer gas is injected into the T-shaped buffer groove 6, and a sealing ring 25 is provided at the connection of the drill collar 3; a connector, which is set on the outer circular wall of the buffer head 2 for connecting the buffer head 2 and the drill collar rod 1; By installing a buffer disc spring 7, non-magnetic inert gas (pre-charge pressure 0.5-1.5MPa) is injected into the T-shaped buffer groove 6 through the air injection nozzle 24 outside the drill collar 3. After injection, the air injection nozzle 24 is sealed, and the sealing ring 25 at the connection is used to achieve a seal between the drill collar 3 and the buffer head 2, preventing drilling fluid from seeping into the T-shaped buffer groove 6 and avoiding buffer gas leakage. During drilling operations, the drill collar 3 bears the axial impact load and alternating stress transmitted by the drill bit. At this time, the impact load first acts on the drill collar 3 and is transmitted to the buffer disc spring 7 inside the buffer head 2. The buffer disc spring 7 undergoes elastic deformation, initially absorbing the impact energy. The buffer gas in the T-shaped buffer groove 6 is compressed, which increases the gas pressure. Utilizing the compressibility of the gas, it further absorbs high-frequency, small-amplitude impact loads, forming a synergistic buffering effect with the buffer disc spring 7. This prevents the impact load from concentrating on the connection part and the drill collar 1 body. Through the synergistic buffering of the buffer disc spring 7 and the buffer gas, both large-amplitude and high-frequency small-amplitude impact loads are absorbed, effectively reducing the impact stress on the drill collar 1, buffer head 2, and connection parts. This prevents deformation of the drill collar body and connection failure, improving the applicability of the drill collar in deep, high-impact drilling scenarios.

[0021] exist Figures 3-4 The connecting components include: two connecting blocks 8, which are fixedly installed on the outer circular wall of the drill collar rod 1; two connecting frames 9, which are both fixedly installed on the outer circular wall of the buffer head 2; a pressing block 10, which is located inside the connecting frame 9; two movable rods 12, which are fixedly installed on one side of the pressing block 10; two movable holes 11, which are opened on one side of the connecting frame 9, and the movable rods 12 and the movable holes 11 are movably fitted together; a pressing spring 13, which is located outside the movable rods 12; and a cover plate 14 is provided on one side of the connecting frame 9, which is connected to the connecting frame 9 by a hinge 15. By setting up connecting frames 9, with the two connecting frames 9 corresponding one-to-one with the connecting blocks 8, the pressing block 10 is squeezed by the connecting block 8 and moves into the connecting frame 9, causing the movable rod 12 to slide along the movable hole 11. At the same time, it compresses the pressing spring 13, which generates a reverse elastic force, pushing the pressing block 10 to press tightly against the connecting block 8, thus achieving elastic pre-tightening and limiting of the buffer head 2 and the drill collar rod 1, forming a double fixation with the threaded connection. Finally, the cover plate 14 is closed by the hinge 15 to protect the pressing block 10, movable rod 12, and pressing spring 13 inside the connecting frame 9, improving the anti-loosening and anti-wear capabilities of the connection parts, avoiding the failure of the buffer components and corrosion of the parts, and extending the service life of the drill collar downhole.

[0022] exist Figure 7In the drill collar rod 1, a connecting sleeve 18 is provided inside. The connecting sleeve 18 has several reinforcing holes 19 inside. Reinforcing ribs 20 are provided inside the reinforcing holes 19. Two connecting holes 16 are provided on the outer circular wall of the drill collar rod 1. Connecting bolts 17 are threaded into the connecting holes 16. Metal reinforcing mesh 21 is provided inside the connecting sleeve 18. A high-molecular polyethylene protective outer layer 22 is provided on the outer layer of the metal reinforcing mesh 21. Non-magnetic sealant is applied to the connection between the connecting sleeve 18 and the drill collar rod 1, the buffer head 2 and the drill collar head 3. The drill collar rod 1, the buffer head 2, the drill collar head 3, the buffer components and the connecting parts are all made of non-magnetic materials. By setting up the connecting sleeve 18, the metal reinforcing mesh 21 is first tightly attached to the inner wall of the connecting sleeve 18, and the outer protective layer 22 of high molecular weight polyethylene is wrapped around the outside of the metal reinforcing mesh 21 through a hot-coating process, thus completing the prefabrication of the connecting sleeve 18; then the reinforcing rib 20 is embedded into the reinforcing hole 19 inside the connecting sleeve 18, and the reinforcing rib 20 is fixed to the connecting sleeve 18 by welding process, so as to ensure that the reinforcing rib 20 and the connecting sleeve 18 form an integral whole and improve the strength of the connecting sleeve 18 itself; The prefabricated connecting sleeve 18 is inserted into the drill collar rod 1, aligned with the connecting hole 16 on the outer circular wall of the drill collar rod 1, and connected by threaded bolts 17 to firmly fix the connecting sleeve 18 to the drill collar rod 1, achieving integrated fixation of the connecting sleeve 18 and the drill collar rod 1. Non-magnetic sealant is evenly applied to the connection points of the connecting sleeve 18 and the drill collar rod 1, the connection points of the connecting sleeve 18 and the buffer head 2, and the connection points of the connecting sleeve 18 and the drill collar head 3. Then, the connection between the buffer head 2 and the drill collar rod 1 is completed. The connection between the drill collar 3 and the buffer head 2, after the non-magnetic sealant has cured, forms a sealing barrier to prevent corrosive substances such as downhole drilling fluid and high-sulfur media from seeping into the connection and the interior of the drill collar 1, while also avoiding local magnetic leakage. Combined with the assembly of the original connectors and buffer structure, the entire drill collar assembly is completed. During drilling operations, the drill collar 1 needs to withstand huge axial pressure, torsional force, and impact loads. At this time, the reinforcing ribs 20 inside the connecting sleeve 18 cooperate with the reinforcing holes 19 to effectively disperse the stress of the drill collar 1, avoid stress concentration, and improve the deformation resistance and fracture resistance of the drill collar 1. The metal reinforcing mesh ribs 21 further enhance the toughness and impact resistance of the connecting sleeve 18, preventing the connecting sleeve 18 from cracking due to impact loads. The high-molecular-weight polyethylene protective outer layer 22 can effectively isolate the downhole drilling fluid and corrosive media from eroding the inner wall of the connecting sleeve 18 and the drill collar 1, while reducing the friction between the inside of the drill collar 1 and the measurement while drilling cable, protecting the cable from damage.

[0023] The working principle of this invention is as follows: Before drilling operations, the drill collar is pre-assembled and pre-treated. Non-magnetic inert gas with a pre-charge pressure of 0.5-1.5 MPa is injected into the T-shaped buffer groove 6 inside the buffer head 2 through the air injection nozzle 24 outside the drill collar head 3. After injection, the air injection nozzle 24 is sealed. The sealing ring 25 at the connection between the drill collar head 3 and the buffer head 2 forms a sealing barrier, preventing drilling fluid from seeping into the T-shaped buffer groove 6 and preventing buffer gas leakage. Simultaneously, the pressure block 10 in the connector is squeezed by the connecting block 8, causing the movable rod 12 to slide along the movable hole 11. The compression spring 13 is activated and compressed. The reverse elastic force generated by the compression spring 13 pushes the compression block 10 to press tightly against the connecting block 8 to achieve elastic pre-tightening and limiting. It forms a double fixation with the threaded connection. After the cover plate 14 is closed by the hinge 15, it forms protection for the internal components of the connecting frame 9. After the connecting sleeve 18 is prefabricated, it is fixed to the drill collar rod 1 by the connecting bolt 17 to achieve integration. The non-magnetic sealant applied at the connection between it and the drill collar rod 1, buffer head 2, and drill collar head 3 forms a sealing barrier after curing, which prevents corrosive substances from penetrating and local magnetic leakage. During drilling operations, the drill collar 3 bears the axial impact load and alternating stress transmitted by the drill bit. This impact load is transmitted to the buffer disc spring 7 in the T-shaped buffer groove 6. The buffer disc spring 7 undergoes elastic deformation to initially absorb the impact energy. At the same time, the buffer gas in the T-shaped buffer groove 6 is compressed and uses its compressibility to further absorb the high-frequency small-amplitude impact load. The two work together to form a synergistic buffering effect to disperse the impact stress. The compression spring 13 further absorbs part of the impact load and radial sway stress through elastic deformation, alleviates stress concentration at the connection point, and limits the relative movement between the buffer head 2 and the drill collar rod 1. Shaking; the reinforcing ribs 20 inside the connecting sleeve 18 cooperate with the reinforcing holes 19 to disperse the axial pressure, torsional force and impact load borne by the drill collar rod 1; the metal reinforcing mesh ribs 21 enhance the toughness and impact resistance of the connecting sleeve 18; the high molecular weight polyethylene protective outer layer 22 isolates the downhole corrosive medium from erosion and reduces internal cable friction damage; all components made of non-magnetic materials, combined with the sealing effect of non-magnetic sealant, ensure the overall non-magnetic stability of the drill collar and avoid interference with the accuracy of drilling measurement. The synergistic effect of each structure enables the drill collar to operate stably and reliably in deep, high-impact drilling scenarios.

[0024] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-strength non-magnetic drill collar, characterized in that, include: Drill collar rod (1), one end of which is provided with a buffer head (2); Drill collar (3), the drill collar (3) is threaded to one side of the buffer head (2), the buffer head (2) is provided with a T-shaped buffer groove (6), and the T-shaped buffer groove (6) is provided with a buffer disc spring (7). Connection end (4), the connection end (4) is disposed on one side of the buffer head (2); Threaded connection groove (5), the threaded connection groove (5) is provided on the inner circular wall surface of the drill collar rod (1), and the threaded connection groove (5) is threadedly connected to the connecting end (4); A buffer component is disposed outside the drill collar (3) for buffering the drill collar (3).

2. The high-strength non-magnetic drill collar according to claim 1, characterized in that, The buffer component includes: Air injection hole (23) is provided on the outer circular wall surface of the drill collar (3); Air injection nozzle (24), which is fixedly installed inside the air injection hole (23); The T-shaped buffer groove (6) is filled with buffer gas; A connector is provided on the outer circular wall of the buffer head (2) for connecting the buffer head (2) to the drill collar rod (1).

3. A high-strength non-magnetic drill collar according to claim 2, characterized in that, The connector includes: Two connecting blocks (8) are fixedly installed on the outer circular wall of the drill collar rod (1); Two connecting brackets (9) are fixedly installed on the outer circular wall of the buffer head (2); A pressing block (10) is disposed inside the connecting frame (9); Two movable rods (12) are fixedly installed on one side of the pressing block (10); Two movable holes (11) are provided on one side of the connecting frame (9), and the movable rod (12) is movably fitted together with the movable holes (11); A compression spring (13) is disposed outside the movable rod (12).

4. A high-strength non-magnetic drill collar according to claim 3, characterized in that, A cover plate (14) is provided on one side of the connecting frame (9), and the cover plate (14) is connected to the connecting frame (9) by a hinge (15).

5. A high-strength non-magnetic drill collar according to claim 1, characterized in that, The drill collar rod (1) is provided with a connecting sleeve (18) inside, and the connecting sleeve (18) is provided with a number of reinforcing holes (19) inside, and the reinforcing holes (19) are provided with reinforcing ribs (20).

6. A high-strength non-magnetic drill collar according to claim 5, characterized in that, The outer circular wall of the drill collar rod (1) has two connecting holes (16), and the connecting holes (16) are threaded with connecting bolts (17).

7. A high-strength non-magnetic drill collar according to claim 6, characterized in that, The connecting sleeve (18) is provided with a metal reinforcing mesh (21) inside, and a high molecular weight polyethylene protective outer layer (22) is provided on the outer layer of the metal reinforcing mesh (21).

8. A high-strength non-magnetic drill collar according to claim 1, characterized in that, A sealing ring (25) is provided at the connection of the drill collar (3).

9. A high-strength non-magnetic drill collar according to claim 5, characterized in that, Non-magnetic sealant is applied to the connection points between the connecting sleeve (18) and the drill collar rod (1), the buffer head (2) and the drill collar head (3).

10. A high-strength non-magnetic drill collar according to claim 5, characterized in that, The drill collar rod (1), buffer head (2), drill collar head (3), buffer components, and connectors are all made of non-magnetic materials.

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