A roller cone drill bit for oil exploration

Abstract

This invention relates to the technical field of petroleum exploration equipment and discloses a roller cone drill bit for petroleum exploration and extraction. To solve the problem of tooth detachment during operation, the blunt tooth has a "T"-shaped structure. During installation, the tail end of the blunt tooth is clamped and secured between the outer and inner sleeves. During operation, the head end of the blunt tooth extending from the outer sleeve performs rock breaking work, while the tail end of the blunt tooth cannot move or detach from the outer sleeve due to the clamping restriction. This method ensures that the blunt tooth cannot detach from the outer sleeve after installation, ultimately achieving the effect of preventing tooth detachment.

Description

Technical Field

[0001] This invention relates to the technical field of petroleum exploration equipment, and in particular to a roller cone drill bit for petroleum exploration and extraction. Background Technology

[0002] In oil exploration and production, a roller cone bit is a tool that breaks rock through rotation. Its core component is a conical roller cone that can rotate on its own axis and revolve around the drill bit's axis. The roller cone's surface is inlaid with carbide teeth. Under drilling pressure, the teeth break the rock through a combination of impact, crushing, and shearing actions. The bit is highly adaptable and has become one of the most widely used rock-breaking tools in oil drilling.

[0003] However, existing tooth fixing processes for roller cone drill bits generally employ an "interference fit" press-fit process, where alloy teeth are mechanically pressed into the tooth hole of the roller cone for fixation. This process, however, has extremely stringent parameter control requirements: if the interference fit is too large, the stress concentration generated during press-fitting can easily lead to metal fatigue in the roller cone body, and even cause shell cracking; if the interference fit is insufficient or the pressing depth is too shallow, the alloy teeth are highly susceptible to loosening or falling off under the high-frequency vibration and impact loads of the downhole drilling tool, causing abnormal drill bit failure. Therefore, there is an urgent need for a device that can ensure tooth prevention of falling off. Summary of the Invention

[0004] This invention proposes a roller cone drill bit for oil exploration and extraction, which has the advantage of preventing tooth loss, thereby solving the problem of tooth loss during operation mentioned in the background art.

[0005] To achieve the above objectives, this application adopts the following technical solution: a roller cone drill bit for oil exploration and extraction, comprising: a drill frame with a drill arm fixedly connected to its lower part; a bearing fixed to the inner side of the drill arm; an inner sleeve fitted onto the end of the drill arm, with the rotating shaft of the inner sleeve tightly installed with the bearing; an outer sleeve coaxially fixedly installed on the outer side of the inner sleeve; blunt teeth, with the tip protruding from the outer sleeve for breaking rock formations; and the tail end clamped and secured by the inner sleeve and the outer sleeve for preventing the blunt teeth from dislodging.

[0006] Furthermore, blunt teeth are T-shaped.

[0007] Furthermore, an installation groove is provided on the side of the inner sleeve seat, in which a toothed seat is movably installed. A toothed tooth that passes through the outer sleeve seat is fixedly installed on the toothed seat, and a spring is fixedly connected between the toothed seat and the outer sleeve seat. When drilling into soft formations, the toothed tooth pushed by the spring extends to scrape the soft formations. When drilling into hard formations, the toothed tooth retracts into the outer sleeve seat to achieve self-protection.

[0008] Furthermore, there are multiple mounting slots, and these multiple mounting slots are arranged in a ring at equal angles on the side of the inner sleeve.

[0009] Furthermore, a jet hole communicating with the inner cavity of the drill frame is provided at the bottom end of the drill frame.

[0010] Furthermore, a guide groove is provided in the middle of the inner sleeve, and a drain hole is provided at the end of the outer sleeve near the inner sleeve. A baffle groove is provided in the middle of the inner sleeve and on the outer side of the end of the outer sleeve. When the drilling fluid in the drain hole is ejected towards the baffle groove, the drilling fluid impacts the outer side of the outer sleeve through the baffle groove.

[0011] Furthermore, a forced return push rod is fixedly installed at the end of the tooth seat, and a forced reset push seat is fixed at the top of the inner side of the drill arm; when the forced return push rod passes the forced reset push seat, the tooth retracts into the outer sleeve seat, and the soil layer on the outer side of the tooth is scraped out by the outer sleeve seat.

[0012] Furthermore, the surface shape of the forced reset push seat is "V".

[0013] Furthermore, the tips of the blunt teeth are spherical.

[0014] Furthermore, the tip of the canine tooth is tapered.

[0015] The beneficial effects of this invention are as follows: This invention provides a roller cone drill bit for oil exploration and extraction. Through a "T"-shaped blunt tooth design, the tail end of the blunt tooth is securely clamped and tightened during installation via the coordinated action of the outer and inner sleeves. When the drill bit is in operation, the tip of the blunt tooth extending from the outer sleeve undertakes the task of rock breaking; its tail end, due to the double clamping restriction of the outer and inner sleeves, cannot move or detach from the outer sleeve. This design ensures that the blunt tooth is firmly fixed to the outer sleeve after installation, effectively preventing tooth loss. Attached Figure Description

[0016] 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: Figure 1 and Figure 2 This is a schematic diagram of the overall external three-dimensional structure of the present invention; Figure 3 This is a schematic diagram of the overall internal planar cross-sectional structure of the present invention; Figure 4 For the present invention Figure 3 Enlarged structural diagram of the area at point E in the middle; Figure 5 This is a schematic diagram of the three-dimensional cross-sectional structure of the drill arm of the present invention; Figure 6 This is a schematic diagram showing the installation position and three-dimensional structure of the forced reset push base of the present invention; Figure 7 This is a schematic diagram of the external three-dimensional structure of the inner sleeve of the present invention; Figure 8 This is a schematic diagram showing the installation positions and three-dimensional structure of each component on the tooth holder of the present invention; Figure 9 This is a three-dimensional structural diagram of the blunt tooth of the present invention; Figure 10 This is a schematic diagram of the external three-dimensional structure of the outer casing of the present invention.

[0017] In the diagram: 1. Drill frame; 101. Jet hole; 2. Drill arm; 3. Outer sleeve seat; 301. Drain hole; 4. Inner sleeve seat; 401. Baffle groove; 402. Mounting groove; 5. Blunt tooth; 6. Pointed tooth; 7. Pointed tooth seat; 701. Spring; 702. Forced return push rod; 8. Bearing; 9. Forced reset push seat. Detailed Implementation

[0018] 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.

[0019] Example 1, please refer to Figures 1-3 As can be seen, the drill frame 1 serves as the mounting and support for the entire roller cone drill bit. Its top is threaded for connection to the drill string, and three drill arms 2 arranged in annular angles are fixedly connected to its lower part. Furthermore, the bottom of the drill frame 1 has a jet hole 101 communicating with its inner cavity. High-pressure drilling fluid is typically supplied to the inner cavity of the drill frame 1 using a drilling pump. The drilling fluid is ejected from the jet hole 101, forming a jet that carries away rock cuttings.

[0020] Combination Figure 3 , Figure 5 and Figure 7 It can be seen that a bearing 8 is installed inside the drill arm 2, and the rotating shaft of the inner sleeve 4 is installed inside the bearing 8. A nut is threaded to the end of the rotating shaft, thereby securing the rotating shaft of the inner sleeve 4 to the inside of the bearing. The middle part of the inner sleeve 4 is relatively sealed to the drill arm 2. Under the constraint and guidance of the bearing 8 and the end of the drill arm 2, the inner sleeve 4 can rotate along its rotating shaft. Figure 7It can be seen that the first end of the inner sleeve 4 is frustum-shaped, and correspondingly, the outer sleeve 3 is coaxially arranged on the outer side of the inner sleeve 4, also frustum-shaped. Generally, a threaded rod is coaxially fixedly connected to the top of the first end of the inner sleeve 4, and the outer sleeve 3 is fitted onto the threaded rod, achieving coaxial arrangement between the outer sleeve 3 and the inner sleeve 4, and is secured with a nut, thus fixing the outer sleeve 3 onto the inner sleeve 4. From Figure 3 As can be seen, a certain gap remains between the outer sleeve 3 and the inner sleeve 4 after installation. This gap serves as the installation space for the tail end of the blunt tooth 5. Specifically, in conjunction with... Figure 9 As can be seen, the blunt tooth 5 is T-shaped, and the end of the blunt tooth 5 is generally spherical or conical. In this application, the spherical shape is used as an example.

[0021] In practical applications, a circular hole is provided on the side of the outer sleeve 3 to facilitate the passage of the blunt tooth 5, ensuring that the head end of the blunt tooth 5 can pass through the circular hole on the outer sleeve 3, while the tail end remains inside the outer sleeve 3. After the outer sleeve 3 and the inner sleeve 4 are assembled and fixed, the tail end of the blunt tooth 5 is fixed by the clamp between the outer sleeve 3 and the inner sleeve 4, thereby ensuring that the blunt tooth 5 is firmly installed on the outer sleeve 3. In the subsequent rock breaking process, the end of the blunt tooth 5 extending out of the outer sleeve 3 is used for rock breaking, while the jet hole 101 discharges the crushed rock from the well hole.

[0022] Because the blunt tooth 5 uses its tail end for limiting and fixing, it is ensured that it cannot detach from the outer sleeve 3 during the rock breaking process.

[0023] Example 2 is a further improvement on Example 1. Please refer to Example 1. Figures 3-5 , Figure 7 As can be seen from Figure 8, the inner sleeve 4 has multiple mounting grooves 402 arranged in annular angles on its side. A toothed seat 7, which reciprocates radially along the inner sleeve 4, is movably mounted in each mounting groove 402. The surface of the toothed seat 7 is a right-angled triangle, and a toothed tooth 6, passing through the outer sleeve 3, is fixedly mounted on the inclined surface of the toothed seat 7. The end shape of the toothed tooth 6 can be wedge-shaped, conical, oval, spoon-shaped, etc. Meanwhile, combined with... Figure 3 and Figure 5 It can be seen that a spring 701 is fixedly connected between the tooth holder 7 and the outer sleeve 3. The tooth holder 7, pushed by the spring 701, always tends to extend the tooth 6 from the side of the outer sleeve 3.

[0024] During drilling, soft formations (soil layers) are loose and easy to drill, but prone to mud pockets, so drill bits with pointed teeth 6 are often used; hard formations (rock layers) are harder, so drill bits with blunt teeth 5 are often used. In traditional drilling, soil layers require the use of pointed drill bits first, as these can efficiently scrape and cut like a plow, allowing for faster drilling. When drilling into hard formations, blunt teeth such as spherical or conical teeth need to be replaced to crush and chisel the rock under high stress. This means that a single set of drill bits cannot perfectly handle alternating soft and hard formations, requiring frequent tripping and replacement, each tripping and retraction consuming significant time and cost. The advantage of this application is that, under normal conditions, the pointed tooth seat 7 moves radially outward along the inner sleeve seat 4 under the elastic force of the spring 701, causing the pointed teeth 6 fixed on the pointed tooth seat 7 to be pushed out from the side of the outer sleeve seat 3. Under normal conditions, the extended length of the pointed teeth 6 is relatively greater than that of the blunt teeth 5. In this way, during drilling, when drilling into soft formations, the pointed teeth 6, pushed by spring 701, extend relatively, thus scraping and cutting the soft formation and ensuring the drilling efficiency of drill frame 1. When drilling into hard formations, the pointed teeth 6, upon reaching the rock layer, will retract into the outer sleeve 3 due to the higher strength of the rock layer. This will cause the pointed teeth 6 to compress spring 701, thus effectively protecting the hard formation through the retraction of the pointed teeth 6. Subsequently, since the blunt teeth 5 cannot retract, upon reaching the hard formation, they are subjected to downward impact pressure, forcing the blunt teeth 5 to break the rock layer.

[0025] In summary, this embodiment 2 can autonomously switch between blunt teeth 5 and pointed teeth 6 according to the hardness of the formation. This ensures that when the equipment is in soft formation, the extended pointed teeth 6 enable a faster drilling rate. When encountering hard formations with greater strength, the retraction of the pointed teeth 6 provides buffer protection, thus preventing the pointed teeth 6 with their sharp tips from breaking due to excessive impact load on a single tooth.

[0026] Example 3 is a further improvement on Example 2. The drill arm 2 and the inner sleeve 4 are connected via a bearing 8. Traditionally, to achieve a seal on the bearing 8, a sealing gasket is used to isolate the bearing 8 from the working environment. However, with prolonged operation, this seal is prone to wear and failure, allowing debris from the working environment to easily penetrate the bearing 8, ultimately causing jamming when the inner sleeve 4 rotates. Example 3 addresses this problem by combining... Figure 3 , Figure 5 and Figure 10It can be seen that the inner cavity of the drill arm 2 is connected to the inner cavity of the drill frame 1. The drilling fluid in the inner cavity of the drill frame 1 can pass through the bearing 8. On the one hand, the liquid medium lubricates and cools the bearing 8. On the other hand, when the drilling fluid is continuously discharged from the bearing 8 in one direction, its pressure is relatively greater than the ambient pressure during drilling. Therefore, the debris generated during drilling will not be unable to enter the bearing 8, thus avoiding the phenomenon of jamming caused by the appearance of debris in the bearing 8.

[0027] Moreover, combined Figure 3 , Figure 4 and Figure 8 It can be seen that a rectangular guide groove is provided in the middle of the inner sleeve 4, that is... Figure 3 and Figure 4 As shown in section A, the drilling fluid in the inner cavity of drill arm 2 can directly enter the area between inner sleeve 4 and outer sleeve 3 through the connection of the guide groove. At the same time, multiple drainage holes 301 arranged at equal angles are opened at the end of outer sleeve 3 near inner sleeve 4. The drainage holes 301 can be used to discharge the drilling fluid in the area between inner sleeve 4 and outer sleeve 3, thereby ensuring that the coolant in the inner cavity of drill frame 1 can be continuously ejected outward from the drainage holes 301 after being transported through the inner cavity of drill arm 2 and inner sleeve 4, thus ensuring that the drilling fluid in the inner cavity of drill arm 2 is always discharged outward in a positive direction.

[0028] More importantly, combining Figure 3 and Figure 4 It is evident that a baffle groove 401 is provided in the middle of the inner sleeve 4 and on the outer side of the end of the outer sleeve 3, and the drain hole 301 is axially oriented towards the baffle groove 401. When the drilling fluid in the drain hole 301 is ejected towards the outer baffle groove 401, the drilling fluid is forced to impact the outer side of the outer sleeve 3 through the baffle groove 401. This not only cools down the blunt teeth 5 and sharp teeth 6 on the outer sleeve 3, but also flushes the blunt teeth 5 and sharp teeth 6 to a certain extent.

[0029] Example 4 is a further improvement on Example 3. In soft formations, due to the adhesive properties of the soil, when the drill bit enters the soft formation, the soil layer easily fills the spaces between the drill bits 6, forming a "plunger." Since the soil in this area has the same strength as the soil in the actual drilling environment, the obstruction from the soil layer between the drill bits 6 directly prevents the drill bits 6 from effectively "penetrating" the soil layer. Even if the drill bit is still rotating, its drilling efficiency will be significantly reduced. Example 4 addresses this problem by combining... Figures 3-6 and Figure 8 It can be seen that each toothed seat 7 has a forced return push rod 702 fixedly installed at its end, which passes through the rectangular guide groove. Correspondingly, a forced reset push seat 9 is fixed on the top of the inner side of the drill arm 2. The surface shape of the forced reset push seat 9 is "V".

[0030] Under normal conditions, the toothed seat 7 is pushed outward by the elastic force of the spring 701, thereby realizing the drilling work in soft soil. During the rotation of the inner sleeve seat 4, when the toothed seat 7 drives the corresponding forced return push rod 702 past the forced reset push seat 9, the toothed seat 7 is relatively far away from the soil. Then, when the forced return push rod 702 passes the forced reset push seat 9, it is guided by the outer arc surface of the forced reset push seat 9, which forces the toothed seat 7 to pull the toothed teeth 6 back into the outer sleeve seat 3. By utilizing the relative sliding between the outer side of the toothed teeth 6 and the outer sleeve seat 3, the soil layer on the outer side of the toothed teeth 6 is scraped off by the outer sleeve seat 3. Furthermore, due to the retraction of the toothed teeth 6, the actual area between the toothed teeth 6 with soil adhesion is shortened. Then, in conjunction with the flushing of the outer side of the outer sleeve seat 3 by the baffle 401 in embodiment three, the problem of soil layer adhering to the toothed teeth 6 and forming "mud bags" that prevent the toothed teeth 6 from properly penetrating the soil layer is further avoided.

[0031] When drilling into hard formations, the soft soil present in the blunt teeth 5 and sharp teeth 6 will gradually detach under the flushing of drilling fluid. It may also break the mud bag into small pieces under the impact of the formation, and then be carried away by the flushing of drilling fluid.

[0032] 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 roller cone drill bit for oil exploration and extraction, characterized in that, include: The drill frame (1) is fixedly connected to the lower part of the drill arm (2); the bearing (8) is fixed inside the drill arm (2); the inner sleeve (4) is fitted on the end of the drill arm (2), and the rotating shaft of the inner sleeve (4) is fastened to the bearing (8); the outer sleeve (3) is coaxially fixedly installed on the outer side of the inner sleeve (4); the blunt tooth (5) has its head end protruding from the outer sleeve (3) and is used to break the rock layer; the tail end is clamped and fastened by the inner sleeve (4) and the outer sleeve (3) to prevent the blunt tooth (5) from falling off.

2. The roller cone drill bit for oil exploration and extraction according to claim 1, characterized in that, The blunt tooth (5) is T-shaped.

3. The roller cone drill bit for oil exploration and extraction according to claim 1, characterized in that, The inner sleeve (4) has an installation groove (402) on its side. A toothed seat (7) is movably installed in the installation groove (402). A toothed tooth (6) that passes through the outer sleeve (3) is fixedly installed on the toothed seat (7). A spring (701) is fixedly connected between the toothed seat (7) and the outer sleeve (3). When drilling into soft formations, the sharp teeth (6) pushed by the spring (701) extend to scrape the soft formations; when drilling into hard formations, the sharp teeth (6) retract into the outer casing (3) to achieve self-protection.

4. The roller cone drill bit for oil exploration and extraction according to claim 1, characterized in that, There are multiple mounting slots (402), and the multiple mounting slots (402) are arranged in a ring at equal angles on the side of the inner sleeve (4).

5. The roller cone drill bit for oil exploration and extraction according to claim 1, characterized in that, The bottom end of the drill frame (1) is provided with a jet hole (101) that communicates with the inner cavity of the drill frame (1).

6. The roller cone drill bit for oil exploration and extraction according to claim 3, characterized in that, The inner sleeve (4) has a guide groove in the middle, and the outer sleeve (3) has a drain hole (301) at the end near the inner sleeve (4). The inner sleeve (4) has a baffle groove (401) in the middle and on the outside of the end of the outer sleeve (3). When the drilling fluid in the drain hole (301) is ejected towards the baffle groove (401), the drilling fluid impacts the outer side of the outer sleeve (3) through the baffle groove (401).

7. The roller cone drill bit for oil exploration and extraction according to claim 6, characterized in that, A forced return push rod (702) is fixedly installed at the end of the toothed seat (7), and a forced reset push seat (9) is fixed at the top of the inner side of the drill arm (2). When the forced return push rod (702) passes the forced reset push seat (9), the sharp tooth (6) retracts into the outer seat (3), and the soil layer on the outside of the sharp tooth (6) is scraped out by the outer seat (3).

8. The roller cone drill bit for oil exploration and extraction according to claim 7, characterized in that, The surface shape of the forced reset push seat (9) is "V".

9. The roller cone drill bit for oil exploration and extraction according to claim 1, characterized in that, The end of the blunt tooth (5) is spherical.

10. The roller cone drill bit for oil exploration and extraction according to claim 7, characterized in that, The tip of the canine tooth (6) is conical.

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