A drill string structure

Abstract

This utility model discloses a drilling tool structure, relating to the field of drilling tool technology, comprising: a core bit, a core barrel, a screw, and a drill pipe arranged sequentially from bottom to top; one end of the core barrel is provided with a centralizing part, which is connected to the core bit, and the other end of the core barrel is provided with at least one centralizer joint between it and the screw; a pressure booster is provided between the screw and the drill pipe, which is used to provide stable and unfluctuating drilling pressure; wherein, the outer diameter of the core barrel is smaller than the outer diameter of the centralizing part and the outer diameter of the centralizer joint, and the outer diameters of the centralizing part and the centralizer joint are smaller than the outer diameter of the core bit. In the above drilling tool structure, the centralizing part of the core barrel cooperates with the centralizer joint to keep the core barrel centered in the wellbore and prevent it from deviating; by providing a pressure booster, stable and unfluctuating drilling pressure can be provided, extending the life of the core bit; and by using a leak-stopping bypass valve, leak plugging can be achieved without drilling, saving operation time and reducing production costs.

Description

Technical Field

[0001] This utility model relates to the field of drilling tool technology, and in particular to a drilling tool structure. Background Technology

[0002] In core sampling operations during oil and gas drilling, conventional drilling tools often encounter the following technical challenges: First, the core barrel, lacking effective alignment, generates severe radial vibrations during operation, resulting in a harsh working environment for the drill bit and a significantly shortened lifespan; second, manual drilling from the ground makes it difficult to ensure stable drilling pressure, and fluctuations in drilling pressure will also accelerate the damage to the drill bit.

[0003] Therefore, there are still shortcomings and deficiencies in the existing technology. There is an urgent need in the field for a new type of drill bit structure that can provide a stable working environment for the core drill bit to cope with complex core drilling conditions. Utility Model Content

[0004] The purpose of this invention is to provide a drill bit structure that solves the technical problems of lack of effective alignment and difficulty in ensuring stable drilling pressure when using conventional drill bit cores.

[0005] To achieve the above objectives, this utility model provides a drilling tool structure, comprising: a core drill bit, a core cylinder, a screw, and a drill rod arranged sequentially from bottom to top;

[0006] One end of the core tube is provided with a straightening part, and the end of the core tube with the straightening part is connected to the core drill bit. At least one straightening connector is provided between the other end of the core tube and the screw.

[0007] A pressure booster is provided between the screw and the drill pipe, and the pressure booster is used to provide stable and unfluctuating drilling pressure;

[0008] Wherein, the outer diameter of the core-taking cylinder is smaller than the outer diameter of the centralizing part and the outer diameter of the centralizer connector, and the outer diameter of the centralizing part and the outer diameter of the centralizer connector are smaller than the outer diameter of the core-taking drill bit.

[0009] Preferably, a shock absorber is provided between the pressure unit and the drill pipe to generate an impact force to release the drill string when it gets stuck, and the shock absorber is threadedly connected to the pressure unit.

[0010] Preferably, a leakage-blocking bypass valve is provided between the shock absorber and the drill pipe to establish a circulation channel to deal with well leakage when the drill is not stopped. The leakage-blocking bypass valve is threadedly connected to the shock absorber and the drill pipe.

[0011] Preferably, the leak-stopping bypass valve is a ball-operated bypass valve or a pressure-controlled bypass valve.

[0012] Preferably, the pressurizer is a hydraulic pressurizer.

[0013] Preferably, the screw is a low-displacement, high-torque screw.

[0014] Preferably, the straightening part and the core-taking tube are integrally formed or have separate connection structures.

[0015] Preferably, a centralizer joint is provided between the screw and the drill pipe, and the number of centralizer joints between the screw and the drill pipe is one or more.

[0016] Preferably, when there are multiple centralizer joints between the screw and the drill pipe, the multiple centralizer joints are arranged at intervals along the axial direction of the drill string structure.

[0017] Preferably, the drill string structure is suitable for coring operations in vertical, deviated, or horizontal wells.

[0018] Compared to the aforementioned background technology, the drill string structure provided by this utility model allows the centering section of the core barrel to directly contact the wellbore, keeping the core barrel centered within the wellbore and preventing it from deviating. The centering section of the core barrel mates with the centralizer connector, thus forming two or more centering points on the drill string structure. The combined action of these multiple centering points effectively suppresses and absorbs radial vibrations throughout the lower drill string structure, creating an extremely stable working environment for the bottom core bit. By incorporating a pressure booster, stable and unfluctuating drilling pressure can be provided, extending the life of the core bit. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the drill string structure provided in the embodiment of the present utility model during vertical well drilling;

[0021] Figure 2 for Figure 1 Enlarged view of a portion of the central structure;

[0022] Figure 3 This is a schematic diagram of the drill string structure during inclined well drilling provided in an embodiment of the present utility model;

[0023] Figure 4 This is a schematic diagram of the drill string structure provided in the embodiment of the present invention during horizontal drilling.

[0024] Figures 1 to 4Chinese figure labels: 1. Core drill bit; 2. Core tube; 201. Centralizing section; 3. Centralizer connector; 4. Screw; 5. Hydraulic booster; 6. Vibrator; 7. Leak plugging bypass valve; 8. Drill rod. Detailed Implementation

[0025] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0026] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0027] This utility model provides a drill string structure in which the centering part 201 of the core barrel 2 cooperates with the centering connector 3 to keep the core barrel 2 centered in the wellbore and prevent it from deviating. By setting a pressure booster, a stable and unfluctuating drilling pressure can be provided, extending the service life of the core bit 1.

[0028] Please refer to this as well. Figures 1 to 4 The drill bit structure provided by this utility model includes: a core drill bit 1, a core cylinder 2, a screw rod 4 and a drill rod 8 arranged sequentially from bottom to top;

[0029] One end of the core tube 2 is provided with a straightening part 201. The end of the core tube 2 with the straightening part 201 is connected to the core drill bit 1, and the other end is provided with at least one straightener connector 3 between it and the screw 4.

[0030] A pressure booster is provided between the screw 4 and the drill pipe 8. The pressure booster is used to provide stable and unfluctuating drilling pressure.

[0031] Among them, the outer diameter of the core tube 2 is smaller than the outer diameter of the centralizing part 201 and the outer diameter of the centralizer connector 3, and the outer diameter of the centralizing part 201 and the outer diameter of the centralizer connector 3 are smaller than the outer diameter of the core drill bit 1.

[0032] The core drill bit 1 is located at the lower part of the drill string structure, and the upper part of the core drill bit 1 is threadedly connected to the core barrel 2. The center of the core drill bit 1 is hollow. When it rotates at the bottom of the well, it does not cut the rock in the center, but only breaks the rock in a ring-shaped area. In this way, a complete cylindrical rock column (i.e., rock core) is preserved in the middle of the core drill bit 1.

[0033] The core barrel 2 has a hollow cylindrical structure, which provides a protected internal space for the continuous core formed from the core drill bit 1, allowing it to enter and be stored undisturbed. The core barrel 2 is equipped with core claws, which can cut the core at the bottom of the well from the root when the core reaches the predetermined length, reliably capturing the core.

[0034] The core barrel 2 is provided with a centering section 201 on the side near the core drill bit 1. During use, the centering section 201 can directly contact the well wall, keeping the core barrel 2 centered in the wellbore and preventing it from deviating. Through effective centering, the severe radial vibration of the core barrel 2 and even the entire lower drill string structure can be greatly suppressed and reduced.

[0035] At least one centralizer joint 3 is provided between the end of the core barrel 2 away from the core drill bit 1 and the screw 4. The centralizer joint 3 can fit tightly against the well wall in the wellbore, forcing the entire drill string section below it (including the core barrel 2 and the core drill bit 1) to be located in the center of the wellbore. By improving the centering, it provides a stable working environment for the core drill bit 1, ensuring that the core drill bit 1 can perform uniform annular cutting. This not only extends the life of the drill bit, but also ensures that the formed core has a uniform diameter, is complete, and is not easily broken.

[0036] The centering section 201 of the core barrel 2 mates with the centering connector 3, thus forming two or more centering points on the drill string structure. The combined action of these multiple centering points effectively suppresses and absorbs radial vibrations throughout the lower drill string structure (especially the core barrel 2), transforming severe vibrations into minor swaying, thereby creating an extremely stable working environment for the bottom core bit 1. Furthermore, by incorporating a pressure booster, stable and unfluctuating drilling pressure can be provided, extending the lifespan of the core bit 1.

[0037] In some embodiments, a shock absorber 6 is provided between the pressure unit and the drill pipe 8 to generate an impact force to release the stuck drill bit structure. The shock absorber 6 is threadedly connected to the pressure unit.

[0038] Please refer to this as well. Figure 1 , Figure 3 and Figure 4 During normal coring operations, the shock absorber 6 has no impact on the coring process. In cases of complex stuck drill bit conditions during tripping operations, surface personnel can lift the drill string. As the lifting force gradually increases, the internal energy storage structure of the shock absorber 6 continuously stores energy. When the release threshold is reached, the shock absorber 6 will release instantaneously, generating an impact force. This impact force, acting on the stuck point, will facilitate unsticking. If unsticking does not occur, repeated lifting operations can be performed to trigger the shock.

[0039] With this setup, when a stuck drill bit occurs, the shock absorber 6 can effectively release the stuck bit downhole, preventing serious downhole accidents.

[0040] In some embodiments, a leakage-blocking bypass valve 7 is provided between the shock absorber 6 and the drill pipe 8 to establish a circulation channel to deal with well leakage when drilling is not started. The leakage-blocking bypass valve 7 is threadedly connected to the shock absorber 6 and the drill pipe 8.

[0041] Please refer to this as well. Figure 1 , Figure 3 and Figure 4 The bypass valve 7 can establish a new circulation channel for drilling fluid without tripping the drill string, thereby directly pumping plugging material into the formation where leakage has occurred, achieving rapid and efficient downhole plugging. During normal coring operations, the bypass valve 7 has no impact on the coring process. In complex conditions involving low-speed or medium-speed leakage, surface personnel can operate the bypass valve 7 to open / close it for plugging, enabling low-speed or medium-speed plugging operations without tripping the drill string.

[0042] With this setup, when encountering low-speed or medium-speed drilling fluid leakage, the leakage plugging bypass valve 7 can achieve plugging without drilling, saving operation time and reducing production costs.

[0043] In some embodiments, the leak-stopping bypass valve 7 is a ball-operated bypass valve or a pressure-controlled bypass valve.

[0044] The leak-stopping bypass valve 7 can be a ball-operated bypass valve or a pressure-controlled bypass valve. When a ball-operated bypass valve is used, the bypass valve can be opened / closed by inserting balls of different sizes. When a pressure-controlled bypass valve is used, the bypass valve can be opened / closed by controlling the pump pressure.

[0045] In some embodiments, the pressurizer is a hydraulic pressurizer 5.

[0046] The hydraulic booster 5 has no impact on the coring operation during normal coring work. When in use, the hydraulic booster 5 extends a certain distance and applies an axial force downwards under the pressure of the drilling fluid pump, for example, extending within the range of 0.4-0.6m. This axial force is transmitted to the coring bit 1 as the drilling pressure. Within this extension range, the axial force is constant and does not fluctuate drastically. As the coring bit 1 continues to break rock and advance footage, the hydraulic booster 5 continues to extend and maintain a constant axial force, thus providing stable and unfluctuating drilling pressure. This stable drilling pressure provides a stable working environment for the coring bit 1, greatly extending its lifespan. When the drilling footage reaches approximately 0.6m, surface personnel can determine that the hydraulic booster 5 has extended 0.6m, reaching its maximum extension. At this point, manual operation can be performed on the surface to lower the drill string structure by 0.6m (i.e., advance the drill string 0.6m). The hydraulic booster 5 downhole will retract 0.6m under the axial force of the upper drill string structure. Drilling can then continue, and after reaching another 0.6m in footage, surface personnel can advance the drill string another 0.6m. This operation can be repeated cyclically, thus achieving continuous drilling.

[0047] This configuration provides continuous and stable drilling pressure through the hydraulic booster 5, avoiding the deterioration of the working environment of the core drill bit 1 caused by drilling pressure fluctuations, extending the service life of the core drill bit 1, and reducing the overall cost.

[0048] In addition, the hydraulic booster 5 is generally used in the horizontal well drilling process, because the horizontal well drilling process may experience depressurization and idle operation due to friction and the lack of gravity to pressurize downwards.

[0049] In some embodiments, the screw 4 is a low-displacement, high-torque screw 4.

[0050] The screw 4 can be a low-displacement, high-torque screw 4, which has the advantages of small torque fluctuation range, stable operating speed, and low vibration, thus providing a stable working environment for the core drill bit 1 and improving the life of the drill bit. During core drilling operations, a constant displacement of drilling fluid is pumped into the screw 4 to keep its rotational speed constant.

[0051] In some embodiments, the straightening part 201 and the core-taking tube 2 are integrally formed or separately connected.

[0052] Please refer to this as well. Figures 1 to 4 The straightening part 201 can be integrally formed with the core-taking tube 2, or the straightening part 201 can be separately connected with the core-taking tube 2.

[0053] In some embodiments, a centralizer joint 3 is provided between the screw 4 and the drill pipe 8, and the number of centralizer joints 3 between the screw 4 and the drill pipe 8 is one or more.

[0054] Several centralizer joints 3 can also be set between the screw 4 and the drill rod 8, such as one or more. The centralizer joints 3 between the screw 4 and the drill rod 8 work together with the end of the core barrel 2 away from the core drill bit 1 and the centralizer joints 3 between the screw 4 to achieve a better centralizing effect.

[0055] In some embodiments, when there are multiple stabilizer joints 3 between the screw 4 and the drill pipe 8, the multiple stabilizer joints 3 are arranged at intervals along the axial direction of the drill string structure.

[0056] When multiple stabilizer joints 3 are installed between the screw 4 and the drill pipe 8, the multiple stabilizer joints 3 between the screw 4 and the drill pipe 8 are arranged at intervals, thereby achieving a better stabilizing effect. Of course, the multiple stabilizer joints 3 between the screw 4 and the drill pipe 8 can also be arranged sequentially along the axis of the drill string structure. The specific installation positions of the multiple stabilizer joints 3 can be set according to the actual situation and are not limited thereto.

[0057] In some embodiments, the drill string configuration is suitable for coring operations in vertical, deviated, or horizontal wells.

[0058] The drill string structure provided in this embodiment is reasonably designed. By adjusting the number and position of the centralizer joints 3, it can well adapt to the coring operation requirements of various well types such as vertical wells, deviated wells, and horizontal wells, and has strong versatility. Figure 1 The diagram shows a drill string structure used in a vertical well coring operation. Figure 3 The diagram shows a drill string structure used in a deviated well coring operation environment. Figure 4 The diagram shows a drill string structure used in a horizontal well coring operation.

[0059] Conventional coring tools often encounter the problem of leaning against one side of the well wall during coring operations in deviated wells. This causes the coring tube 2 to become misaligned, making it difficult for the coring tube 2 to successfully insert the core, resulting in coring failure. The centralizer 201 and centralizer connector 3 used in the drill string structure provided in this embodiment serve to support the well wall, enabling coring operations under deviated well conditions.

[0060] Conventional coring tools face problems such as lying at the bottom of the well and bending of the entire tool when coring in horizontal wells, making it difficult for the coring tube 2 to enter smoothly and causing coring failure.

[0061] The centralizer 201 and centralizer connector 3 used in the drill string structure provided in this embodiment not only serve to centralize the drill string structure but also to support the wellbore and prevent drill string bending. In practical use, different sizes of centralizer 201 and centralizer connector 3 can be connected on-site to achieve different support effects. The centralizer connector 3 can also be installed in multiple locations to achieve better support, thus avoiding the problems of misalignment and significant drill string bending that occur with conventional coring drill strings in horizontal wells.

[0062] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0063] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of this utility model.

Claims

1. A drill string structure, characterized by include: The core drill bit (1), core cylinder (2), screw (4) and drill rod (8) are arranged sequentially from bottom to top; One end of the core tube (2) is provided with a straightening part (201). The end of the core tube (2) with the straightening part (201) is connected to the core drill bit (1), and the other end is provided with at least one straightening connector (3) between it and the screw (4). A pressure booster is provided between the screw (4) and the drill pipe (8), and the pressure booster is used to provide stable and unfluctuating drilling pressure; Wherein, the outer diameter of the core tube (2) is smaller than the outer diameter of the centering part (201) and the outer diameter of the centering connector (3), and the outer diameter of the centering part (201) and the outer diameter of the centering connector (3) are smaller than the outer diameter of the core drill bit (1).

2. The drill tool structure of claim 1, wherein, A shock absorber (6) is provided between the pressure unit and the drill rod (8) to generate an impact force to release the stuck drill bit structure. The shock absorber (6) is threadedly connected to the pressure unit.

3. The drill tool structure of claim 2, wherein, A leakage-blocking bypass valve (7) is provided between the shock absorber (6) and the drill pipe (8) to establish a circulation channel to deal with well leakage when the drill is not started. The leakage-blocking bypass valve (7) is threadedly connected to the shock absorber (6) and the drill pipe (8).

4. The drill tool structure of claim 3, wherein, The leak-stopping bypass valve (7) is a ball-operated bypass valve or a pressure-controlled bypass valve.

5. The drill tool construction of claim 1 wherein, The pressurizer is a hydraulic pressurizer (5).

6. The drill string structure according to claim 1, characterized in that, The screw (4) is a low displacement, high torque screw (4).

7. The drill string structure according to claim 1, characterized in that, The straightening part (201) and the core tube (2) are either integrally formed or separately connected.

8. The drill tool construction of claim 1 wherein, A centralizer joint (3) is provided between the screw (4) and the drill rod (8), and the number of centralizer joints (3) between the screw (4) and the drill rod (8) is one or more.

9. The drill string structure according to claim 8, characterized in that, When there are multiple centralizer joints (3) between the screw (4) and the drill pipe (8), the multiple centralizer joints (3) are arranged at intervals along the axial direction of the drill string structure.

10. The drill tool construction of any one of claims 1 to 9, wherein, The drilling tool structure is suitable for coring operations in vertical, deviated, or horizontal wells.

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