PDC (Polycrystalline Diamond Compact) drill bit with telescopic auxiliary blades at core part

Abstract

The utility model discloses a core auxiliary blade telescopic PDC (polycrystalline diamond compact) drill bit which comprises a drill bit base body, a containing cavity is formed in the center of the top of the drill bit base body, a high-strength alloy spring is arranged in the containing cavity, and a center blade is inserted into the containing cavity and arranged above the high-strength alloy spring. And a plurality of core conical teeth are uniformly distributed at the top of the central cutter wing at intervals. When the drill bit breaks rocks, the peripheral cutting teeth cut and destroy rocks on the outer ring of the shaft bottom, the center rocks at the center of the shaft bottom push the center blades into the containing cavities to form rock bosses, the hardness of the center rocks is reduced, the springs stop moving after being compressed to a certain degree, the core conical teeth plough and break the rocks, and the higher the hardness of the rocks is, the higher the formed rock bosses are; based on the drill bit, self-adaption and stable drilling speed can be achieved when the drill bit is used for drilling soft and hard stratums, and high drilling speed can be achieved when the drill bit is used for drilling hard stratums.

Description

Technical Field

[0001] The utility model relates to the field of petroleum drilling equipment, in particular to a core auxiliary blade telescopic PDC drill bit. Background Art

[0002] With the continuous deepening of oil exploration and development, shallow and easily exploitable oil and gas resources are becoming less and less. Seeking oil and gas resources in deep strata and complex geological conditions is gradually becoming an important task in current marine and land exploration and development. Deep hard rock usually exhibits properties such as high strength, high hardness, strong abrasiveness, severe heterogeneity and poor drillability during the drilling process. Existing rock breaking tools and drilling methods generally have problems such as slow drilling speed, short drill bit life, long drilling cycle and high drilling cost, which directly restrict the drilling speed of deep wells and ultra-deep wells and the overall benefits of exploration and development.

[0003] PDC drill bits are mainly used in soft to medium-hard formations, but have poor adaptability in hard formations and are prone to tooth collapse, chipping, severe wear, etc. In recent years, continuous improvements and innovations have been made in the cutting teeth, blade shape, blade structure, hydraulic design, etc. of PDC drill bits, which have improved the drilling speed of PDC drill bits in hard formations to a certain extent, but it is still difficult to meet the requirements of efficient rock breaking and increased rotation speed. Due to the different cutting capabilities from the center to the edge of the drill bit, the density of the teeth in the center of the drill bit is relatively small, and the rock breaking speed in the center of the drill bit is slow, thereby limiting the overall rock breaking speed. In addition, the cutting teeth in the center of the drill bit are easily damaged and the tooth density cannot be increased, which limits the overall life of the drill bit.

[0004] For complex formations with both hard and soft layers, the mechanical penetration rate of conventional PDC drill bits is extremely unstable during the drilling process. For harder formations, the mechanical penetration rate of conventional PDC drill bits is relatively low, while for softer formations, the mechanical penetration rate of conventional PDC drill bits is relatively high, which leads to chatter during the drilling process. Chatter causes the drill bit to vibrate continuously at high frequencies in the formation, affecting the stability of the drilling process and thus reducing drilling efficiency. Unstable vibrations can cause excessive wear of drilling tools and other equipment, and may even cause damage to the equipment. This not only increases maintenance costs, but also prolongs drilling downtime. Chatter may also cause the drill bit to deviate from the predetermined drilling trajectory, thereby affecting the drilling quality, which is particularly important for drilling tasks that require accurate positioning of targets underground. Therefore, it is of great significance to design a PDC drill bit that can drill stably and efficiently break rocks. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a core auxiliary blade telescopic PDC drill bit, which can adapt to strata with different hardness, and has high stability and rock breaking efficiency during drilling.

[0006] The utility model is realized by adopting the following technical solutions.

[0007] A core auxiliary blade telescopic PDC drill bit comprises a drill bit base body, a receiving cavity is opened in the center of the top of the drill bit base body, a high-strength alloy spring is arranged in the receiving cavity, a central blade is inserted into the receiving cavity and is placed above the high-strength alloy spring; a plurality of core conical teeth are evenly spaced and arranged on the top of the central blade.

[0008] Furthermore, a plurality of peripheral blades are arranged circumferentially at equal intervals on the drill bit base body, and peripheral cutting teeth are embedded on the peripheral blades along the blade curved surfaces.

[0009] Furthermore, the height of the peripheral blade is higher than the height of the central blade.

[0010] Furthermore, the outer peripheral blade is provided with gauge teeth for maintaining the diameter.

[0011] Furthermore, one end of the high-strength alloy spring is connected to the bottom of the central blade wing, and the other end is connected to the bottom surface of the accommodating cavity.

[0012] Furthermore, nozzle channels are arranged on both sides of the central blade and on the drill base between two adjacent peripheral blades.

[0013] Furthermore, a threaded connection structure for connection is provided at the lower part of the drill base.

[0014] Furthermore, a main flow channel within the drill bit is provided in the drill bit base body, and the main flow channel within the drill bit is communicated with the nozzle flow channel.

[0015] The utility model obtains the following beneficial effects.

[0016] (1) The utility model provides a single-row cutting structure at the core of the PDC drill bit, and a receiving cavity is provided at the lower part of the single-row cutting structure, and a high-strength alloy spring is provided in the receiving cavity, so that the drill bit has very good adaptability to soft and hard formations. When drilling into softer formations, the rock column that enters the middle of the drill bit is short, and the corresponding stress is released at the bottom of the well, making the rock in the center of the drill bit easier to break, thereby improving the overall rock breaking efficiency of the drill bit. When encountering hard formations, the high-strength alloy spring is compressed shorter, and the central rock column generated during rock breaking is longer. The stress released at the bottom of the well is greater, making the hard formation rock in the middle of the drill bit easier to break, thereby improving the crushing efficiency of the hard formation rock. The rock breaking structure of the utility model can make the PDC drill bit adapt well to formations of different hardness, while increasing the drilling speed and making the drilling rate more stable;

[0017] (2) The core of the PDC drill bit of the utility model is movable and removable. When the telescopic structure in the center is damaged, a new corresponding structure can be replaced, thereby extending the service life of the entire drill bit. This effectively solves the problem that when drilling into deep formations, the core of the drill bit has a low tooth density and is easy to wear, which easily leads to core-digging failure, resulting in the failure of the entire drill bit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the utility model;

[0019] Figure 2 It is a cross-sectional view of the utility model;

[0020] Figure 3 This is a structural schematic diagram of the main assembly of the drill bit of the utility model;

[0021] Figure 4 This is a schematic diagram of the structure of the auxiliary blade of the core of the utility model;

[0022] Figure 5 This is a schematic diagram of the structure of the high-strength alloy spring of the utility model;

[0023] Figure 6 This is a schematic diagram of the retraction of the auxiliary blade of the core when the utility model encounters hard rock;

[0024] Figure 7 It is a schematic diagram of the auxiliary blade of the core extending when the utility model encounters soft rock.

[0025] Among them: 1. peripheral cutting teeth, 2. peripheral blades, 3. drill base, 4. gauge teeth, 5. core tapered teeth, 6. center blades, 7. nozzle flow channel, 8. threaded connection structure, 9. high-strength alloy spring, 10. accommodating cavity, 11. main flow channel in the drill. DETAILED DESCRIPTION

[0026] The technical solution of the utility model will be clearly and completely described below through specific implementation methods.

[0027] like Figure 1-5 As shown, a core auxiliary blade telescopic PDC drill bit includes peripheral cutting teeth 1, peripheral blades 2, a drill bit base 3, a diameter protection structure 4, core conical teeth 5, center blades 6, nozzle flow channels 7, a threaded connection structure 8, a high-strength alloy spring 9, an accommodating cavity 10, and a main flow channel 11 in the drill bit.

[0028] The peripheral blade 2 is evenly arranged on the drill bit base 3 in an annular direction, and the peripheral cutting teeth 1 are embedded in the peripheral blade 2 along the blade curved surface; the core conical teeth 5 are evenly arranged on the center blade 6 along the edge of the center blade 6. Preferably, the center blade 6 is a rectangular parallelepiped, and the axis of the core conical teeth 5 is perpendicular to the upper surface of the center blade 6; a receiving cavity 10 is provided on the top of the drill bit base 3, and the central axis of the receiving cavity 10 coincides with the central axis of the drill bit, and the high-strength alloy spring 9 is evenly arranged in the receiving cavity. In the cavity 10, the center blade wing 6 is inserted into the accommodating cavity 10 and is located at the top of the high-strength alloy spring 9. The length and width corresponding to the opening surface of the accommodating cavity 10 correspond to the length and width of the bottom surface of the center blade wing 6 one by one, and are equal in size. The depth of the accommodating cavity 10 is greater than the height of the center blade wing 6; the center blade wing 6 is fixedly connected to the top of the high-strength alloy spring 9, and the bottom end of the high-strength alloy spring 9 is fixedly connected to the bottom surface of the accommodating cavity 10. The outer diameter of the high-strength alloy spring 9 is equal to the width of the accommodating cavity 10. The height of the peripheral blade wing 2 is higher than the height of the center blade wing 6, forming a concave shape in the center of the drill bit. When drilling into rock, the center rock presses the core conical teeth 5 and the center blade wing 6, and the center blade wing 6 presses the high-strength alloy spring 9. The high-strength alloy spring 9 is compressed, and the center blade wing 6 is compressed and retracted together with the high-strength alloy spring 9. The depth of the concave in the center of the PDC drill bit is deepened, and the hardness of the central rock column at the bottom of the well is weakened.

[0029] like Figure 6 As shown, when the core auxiliary blade telescopic PDC drill bit of the utility model is used to drill a stratum with high rock hardness, the peripheral cutting teeth 1 on the peripheral blade 2 first contact the rock. Under the action of drilling pressure and torque, the rock is sheared and broken. As the PDC drill bit drills deeper into the rock, a rock boss is formed at the center of the bottom of the well, and the center boss contacts the core conical teeth 5 on the center blade 6. At this time, the high-strength alloy spring 9 in the accommodating chamber 10 is compressed, and the center blade 6 and the core conical teeth 5 retreat along the inner wall of the accommodating chamber 10. At this time, the height of the rock column of the center boss at the bottom of the well increases, the confining pressure on the rock column at the center of the bottom of the well is unloaded, the hardness of the rock is weakened, and the elastic force of the high-strength alloy spring 9 after being compressed acts on the center blade 6 and the core conical teeth 5. When the pressure on the center rock column at the bottom of the well reaches the pressure at which the rock is destroyed, the rock is destroyed. The PDC drill bit improves the mechanical drilling speed of the drill bit by releasing the confining pressure of the rock at the center of the bottom of the well.

[0030] like Figure 6-7As shown, when the core auxiliary blade telescopic PDC drill bit of the utility model is used to drill soft and hard interlaced strata, the peripheral cutting teeth 1 on the peripheral blade 2 first contact the rock. Under the action of drilling pressure and torque, the rock is sheared and broken. As the PDC drill bit drills deeper into the rock, a rock boss is formed at the center of the bottom of the well. Since the hardness of the rock is relatively high, the height of the rock column formed at the center of the bottom of the well is relatively high, and the high-strength alloy spring 9 in the accommodating chamber 10 is compressed to a relatively large extent. When drilling into a rock with a relatively low rock hardness, the rock strength when the rock is destroyed is relatively low, the high-strength alloy spring 9 in the accommodating chamber 10 is compressed to a relatively small extent, and the center blade 6 and the core conical teeth 5 are compressed and retracted to a relatively small extent. In this way, when drilling into a rock with a relatively high hardness, the center blade 6 and the core conical teeth 5 are pressed back to a relatively large extent, and the hardness of the rock at the center of the bottom of the well is weakened to a relatively large extent. When drilling into rock with lower hardness, the center blade 6 and the core conical teeth 5 are pressed back to a relatively small extent, and the hardness of the rock at the center of the bottom of the well is weakened to a relatively small extent, thereby ensuring the rock breaking efficiency and mechanical drilling speed stability of the PDC drill bit when breaking rocks.

[0031] The core of the PDC drill bit is prone to wear due to its low tooth density and low linear speed, and core-digging failure may occur during oil drilling. The center blade wing 6 and the core conical teeth 5 in the utility model are movably arranged relative to the base of the drill bit. During the drilling process, the core is severely worn after long-term work, and the core auxiliary blade can be replaced without causing the entire drill bit to be scrapped.

[0032] The embodiments described above are merely descriptions of preferred implementation modes of the present invention, and are not intended to limit the concept and scope of the present invention. Without departing from the design concept of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field should fall within the protection scope of the present invention. The technical contents for which protection is sought in the present invention have been fully recorded in the technical requirements.

Claims

1. A core auxiliary blade telescopic PDC drill bit, comprising a drill bit base (3), characterized in that: A receiving cavity (10) is provided at the center of the top of the drill bit base (3), a high-strength alloy spring (9) is provided in the receiving cavity (10), a central blade (6) is inserted into the receiving cavity (10) and is placed above the high-strength alloy spring (9); a plurality of core conical teeth (5) are evenly spaced and arranged on the top of the central blade (6).

2. A core auxiliary blade retractable PDC drill bit according to claim 1, characterized in that: A plurality of peripheral blades (2) are arranged at equal intervals in the circumferential direction on a drill bit base body (3), and peripheral cutting teeth (1) are embedded on the peripheral blades (2) along the blade curved surface.

3. A core auxiliary blade telescopic PDC drill bit according to claim 2, characterized in that: The height of the peripheral blade (2) is higher than the height of the central blade (6).

4. A core auxiliary blade retractable PDC drill bit according to claim 2, characterized in that: The outer peripheral blade (2) is provided with a gauge-keeping tooth (4) for maintaining the gauge.

5. The core auxiliary blade telescopic PDC drill bit according to claim 1, characterized in that: One end of the high-strength alloy spring (9) is connected to the bottom of the central blade (6), and the other end is connected to the bottom surface of the accommodating cavity (10).

6. The core auxiliary blade retractable PDC drill bit according to claim 1, characterized in that: Nozzle flow channels (7) are arranged on both sides of the central blade (6) and on the drill base (3) between two adjacent peripheral blades (2).

7. The core auxiliary blade telescopic PDC drill bit according to claim 1, characterized in that: A threaded connection structure (8) for connection is provided at the lower part of the drill bit base body (3).

8. The core auxiliary blade retractable PDC drill bit according to claim 1, characterized in that: The drill bit base body (3) is provided with a drill bit internal main flow channel (11), and the drill bit internal main flow channel (11) is communicated with the nozzle flow channel (7).

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