Geological drilling PDC drill bit

Abstract

The invention relates to the technical field of drilling equipment, and discloses a geological drilling PDC drill bit which comprises a limiting plate, the limiting plate is connected with a sand blocking barrel with a filter screen at the bottom through a two-connecting-rod structure, the upper portion of the sand blocking barrel is provided with a limiting structure used for preventing the sand blocking barrel from penetrating through a water nozzle, and the two-connecting-rod structure is composed of two connecting rods; the ends of the two connecting rods are connected through a middle rotating shaft, and when the limiting structure of the sand blocking cylinder abuts against the end of the mounting hole, the middle rotating shaft of the two-connecting-rod structure deviates towards one side. According to the PDC drill bit for geological drilling, the sand blocking cylinder is used for blocking the water nozzle, silt is effectively prevented from entering the water nozzle, the water nozzle is prevented from being blocked, meanwhile, the two-connecting-rod structure is used for supporting and driving the sand blocking cylinder to move, the sand blocking cylinder can be continuously and repeatedly used and cannot fall into the well bottom, drilling is not affected, and meanwhile the two-connecting-rod structure has large rigidity when not folded; the sand blocking barrel can be guaranteed not to be affected by external silt, the sand blocking barrel is guaranteed to be separated from the water nozzle when folded, and reliability is higher.

Description

Technical Field

[0001] The present application relates to the technical field of drilling equipment, and in particular to a PDC drill bit for geological drilling. Background Art

[0002] As the core tool of modern drilling operations, PDC (polycrystalline diamond composite) drill bits are widely used in oil and gas exploration due to their advantages such as high mechanical drilling speed and long life.

[0003] During geological drilling, it is inevitable that the drill bit will be lowered into the well midway due to matters such as replacing the drill bit and handling accidents. When the drill bit is lowered into the well midway, if the circulation is not established in advance or the displacement is insufficient, the mud cake scraped from the well wall will directly accumulate at the bottom of the drill bit and block the water eye channel. For this reason, some measures need to be taken to avoid water eye blockage when the drill bit is lowered into the well midway. Common measures include adding a wire mesh cover to the drill bit as a whole. When the drill bit reaches the bottom of the well, the strong mud pressure during drilling is used to destroy the connection between the mesh cover and the drill bit, and the mesh cover falls to the bottom of the well without affecting normal mud injection.

[0004] Although the use of wire mesh covers can effectively reduce water eye blockage, the metal mesh covers falling to the bottom of the well may affect the normal drilling of the drill bit. At the same time, due to the uneven hydraulic distribution in each water eye area of ​​the drill bit, the strength of the mesh covers of each water eye is different. There is a probability that the mesh covers will fall off under mud pressure, and there is also a probability that some mesh covers will not fall off, affecting mud injection. Summary of the invention

[0005] The present application proposes a PDC drill bit for geological drilling, which uses a sand-trapping tube to block a water nozzle, effectively preventing mud and sand from entering the water nozzle and avoiding blockage of the water nozzle. At the same time, a two-link structure is used to support and drive the sand-trapping tube to move, so that the sand-trapping tube can be reused continuously and will not fall to the bottom of the well and affect drilling. At the same time, the two-link structure has greater rigidity when it is not folded, which can ensure that the sand-trapping tube is not affected by external mud and sand. When folded, it ensures that the sand-trapping tube is separated from the water nozzle, which is more reliable.

[0006] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme: a geological drilling PDC drill bit, comprising a drill bit shell, a plurality of blades and mounting holes are arranged on the drill bit shell, a water nozzle is installed in the mounting hole, a water cavity is arranged in the drill bit shell, the water cavity is connected with a water pump, a limit plate is arranged in the water cavity, the limit plate is connected with a sand-trapping cylinder with a filter screen at the bottom through a two-link structure, the upper part of the sand-trapping cylinder is provided with a limit structure for preventing the sand-trapping cylinder from passing through the water nozzle, the two-link structure is composed of two connecting rods, the ends of the two connecting rods are connected by an intermediate rotation The drill bit is connected to the shaft. When the limiting structure of the sand-trapping barrel is pressed against the end of the mounting hole, the middle rotating shaft of the two-link structure deviates to one side. A limiting member is provided in the drill bit housing. The limiting member can limit the middle rotating shaft of the two-link structure from continuing to move toward one side. A telescopic member and a driving structure are also provided in the drill bit housing. When going down the well, the telescopic member remains in an extended state and contracts under the mud pressure during drilling. When the telescopic member contracts, the limiting member is triggered to act, so that the limiting member releases the limitation on the middle rotating shaft of the two-link structure, and the driving structure drives the two-link structure to continue to fold.

[0007] Preferably, the telescopic member includes a telescopic cavity and a telescopic rod, the telescopic rod is connected to a limit block via a connecting arm, the limit block is arranged on the moving path of the middle rotating shaft of the two-link structure, the limit block moves as the telescopic rod contracts, and leaves the moving path of the middle rotating shaft after moving.

[0008] Preferably, the driving structure is an elastic pull rope, and two ends of the elastic pull rope are respectively fixedly connected to two ends of the two-link structure.

[0009] Preferably, the driving structure is a lifting rod, which is fixedly connected to a connecting arm, and the connecting arm is located below the moving path of the intermediate rotating shaft. As the telescopic rod continues to contract, the lifting rod moves with the intermediate rotating shaft, so that the two-link structure is folded, which is easier to install.

[0010] Preferably, the telescopic member further comprises an air cavity which is annular and is disposed on the limiting plate. The air cavity is connected to the top of the telescopic cavity. The telescopic cavity and the air cavity are filled with gas to increase the telescopic amount of the telescopic member.

[0011] Preferably, the sand-trapping cylinder includes a cylinder body and a pressure plate, the cylinder body is fixedly connected to a base plate, the pressure plate is connected to a limit plate, the base plate is fixedly connected to a sliding rod, the sliding rod is inserted into the pressure plate and is slidably connected to the pressure plate, and an adjusting bolt is provided on the pressure plate or the base plate, and rotating the adjusting bolt can move the pressure plate and the base plate apart.

[0012] Preferably, a gap is left between the cylinder and the water nozzle.

[0013] Preferably, a closed capsule is provided at the lower end of the cylinder, the cylinder is connected to the bottom plate via a front capsule, and the bottom plate is in communication with the closed capsule.

[0014] The beneficial effects of the present invention are as follows:

[0015] The speed of PDC drill bit is very fast and the frequency is very fast, which may cause the drill bit to lose weight, so it is necessary to increase the speed to drive the drill bit into the wellbore, to prevent the drill bit from getting stuck, and to increase the speed of the drill bit to a certain extent.

[0016] By contracting the telescopic part, the limit part releases the restriction on the folding of the two-link structure, thereby folding the two-link structure. On the one hand, the two-link structure has greater rigidity when it is not folded, which can ensure that the sand-trapping tube is not affected by external mud and sand, and the function of blocking mud and sand will not fail. On the other hand, after the restriction is released, a smaller force can fold the two-link structure, ensuring that the sand-trapping tube is separated from the water nozzle, which is more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art are briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on the provided drawings without creative work:

[0018] Figure 1 is a schematic diagram of Embodiment 1 of the present invention;

[0019] Figure 2 It is a schematic diagram of the three-dimensional structure of the first embodiment of the present invention;

[0020] Figure 3 It is a schematic diagram of the second embodiment of the present invention;

[0021] Figure 4 It is a schematic diagram of the limiting member and the telescopic member in the second embodiment of the present invention;

[0022] Figure 5 For the present invention Figure 4 Bottom view of

[0023] Figure 6 For the present invention Figure 5 Schematic diagram when the two-link structure rotates not toward the central axis;

[0024] Figure 7 It is a schematic diagram of the sand-trapping tube in the second embodiment of the present invention.

[0025] In the figure: 1. drill bit housing; 2. blade; 3. mounting hole; 4. water nozzle; 5. sand retaining tube; 51. cylinder; 52. pressure plate; 53. adjusting bolt; 54. bottom plate; 55. front bag; 56. slide bar; 57. closing bag; 6. limit plate; 7. two-link structure; 8. limit part; 81. connecting arm; 82. limit block; 83. lifting rod; 9. telescopic part; 91. telescopic cavity; 92. telescopic rod; 93. air cavity; 10. elastic pull rope. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] Embodiment 1, as Figure 1-Figure 2A geological drilling PDC drill bit includes a drill bit housing 1, a plurality of blades 2 and mounting holes 3 are arranged on the drill bit housing 1, PDC teeth are arranged on the blades 2, a water nozzle 4 is installed in the mounting hole 3, a water cavity is arranged in the drill bit housing 1, the water cavity is connected with a water pump, the water pump sends mud liquid into the water cavity and sprays it to the bottom of the well through the water hole, a limit plate 6 is arranged in the water cavity, the limit plate 6 is fixedly connected to the inner wall of the drill bit housing 1, the limit plate 6 can be welded to the inner wall of the drill bit housing 1, and can also be installed in the drill bit housing through a reserved mounting hole 1, the limit plate 6 is connected to the sand-trapping cylinder 5 through a two-link structure 7. The sand-trapping cylinder 5 is a hollow cylinder. A filter screen is provided at the bottom of the sand-trapping cylinder 5. Mud can pass through the sand-trapping cylinder 5. At the same time, the filter screen can prevent external mud and sand from entering the drill bit housing 1. The sand-trapping cylinder 5 can be inserted from the upper part of the water nozzle 4. A limit structure is provided on the upper part of the sand-trapping cylinder 5 to prevent the sand-trapping cylinder 5 from passing through the water nozzle 4. The two-link structure 7 is composed of two connecting rods. The ends of the two connecting rods are connected by an intermediate rotating shaft. The upper end of the two-link structure 7 is hinged with the limit plate 6. Then, the lower end of the two-link structure 7 is hinged with the sand-trapping cylinder 5. When the limiting structure of the sand-trapping cylinder 5 is pressed against the end of the mounting hole 3, the middle rotating shaft of the two-link structure 7 deviates to one side. A limiting member 8 is provided in the drill housing 1. The limiting member 8 can limit the middle rotating shaft of the two-link structure 7 from continuing to move toward one side. Since the middle rotating shaft of the two-link structure 7 cannot continue to move, that is, the two-link structure 7 cannot continue to fold, the two ends of the two-link structure 7 cannot continue to approach, so that the sand-trapping cylinder 5 will not retreat under the external mud pressure, ensuring that the external mud and sand are not trapped. It will not enter the water nozzle 4. A telescopic part 9 and a driving structure are also provided in the drill bit housing 1. When going down the well, the telescopic part 9 can overcome the low-pressure mud pressure and maintain the extended state. When drilling, the telescopic part 9 shrinks under the high-pressure mud pressure. When the telescopic part 9 shrinks, the limit part 8 is triggered to act, so that the limit part 8 releases the restriction on the middle rotating shaft of the two-link structure 7. After the limit part 8 releases the restriction on the middle rotating shaft, the driving structure drives the two-link structure 7 to continue to fold, so that the sand-trapping tube 5 leaves the water nozzle 4, and does not affect the normal injection of mud.

[0028] See also Figure 4 The telescopic member 9 includes a telescopic cavity 91 and a telescopic rod 92. The telescopic rod 92 is connected to a limit block 82 through a connecting arm 81. The limit block 82 is arranged on the moving path of the middle rotating shaft of the two-link structure 7. When the middle rotating shaft of the two-link structure 7 moves to one side, it will press against the limit block 82. The limit block 82 will limit the further folding of the two-link structure 7. The limit block 82 and the connecting arm 81 move as the telescopic rod 92 contracts. After the limit block 82 moves, it leaves the moving path of the middle rotating shaft, and the two-link structure 7 can be further folded, and the sand blocking tube 5 is pulled out of the water nozzle 4.

[0029] The driving structure is an elastic rope 10, and the two ends of the elastic rope 10 are fixedly connected to the two ends of the two-link structure 7 respectively. When the limit block 82 leaves, the two ends of the two-link structure 7 quickly approach each other under the tension of the elastic rope 10, so that the sand-trapping tube 5 leaves the water nozzle 4.

[0030] Embodiment 2: In Embodiment 1, since the elastic force of the elastic rope 10 always exists, the sand trap 5 always tends to leave the water nozzle 4, which is not convenient for installation. Therefore, based on Embodiment 1, the setting mode of the driving structure is changed. Please refer to Figure 3-Figure 5 In the second embodiment, the driving structure is a lifting rod 83, which is fixedly connected to the connecting arm 81. The connecting arm 81 is located below the middle rotating shaft. When the limit block 82 leaves, as the telescopic rod 92 continues to shrink, the lifting rod 83 contacts the middle rotating shaft, and the lifting rod 83 lifts the middle rotating shaft to fold the two-link structure 7.

[0031] The two connecting rod structures 7 and the limiting member 8 in the first and second embodiments are flexibly arranged according to the position of the mounting hole 3. Figure 5 In the embodiment, when the inner diameter of the drill bit is small, the rotation direction of the two-link structure 7 is not toward the central axis, and the connecting arm 81 is adaptively adjusted to the rotation direction of the central axis of the two-link structure 7. In other embodiments, the folding directions of each two-link structure 7 may be different, and the connecting arm 81 is adaptively adjusted to the setting mode of each two-link structure 7 to ensure that the limit block 82 is on the moving path of the central rotation and can leave, and does not interfere with the folding of the two-link structure 7, and the lifting rod 83 is always on the moving path of the central axis and moves with the central axis.

[0032] The telescopic member 9 also includes an air cavity 93, which is annular and is arranged on the limit plate 6. The air cavity 93 is connected to the top of the telescopic cavity 91. The telescopic cavity 91 and the air cavity 93 are filled with gas, which can be air. The initial air pressure makes the telescopic rod 92 in an extended state. When the mud pressure increases, the pressure compresses the gas, causing the telescopic rod 92 to shrink, and the air cavity 93 increases the gas volume. When the air cavity 93 shrinks, the gas volume changes relatively little, making it easier to be compressed.

[0033] See also Figure 7The sand-trapping cylinder 5 includes a cylinder body 51 and a pressure plate 52. The cylinder body 51 is fixedly connected with a bottom plate 54. The pressure plate 52 is connected with a limit plate 6. The bottom plate 54 is fixedly connected with a slide rod 56. The slide rod 56 is inserted into the pressure plate 52 and is slidably connected with the pressure plate 52. A limit structure is provided at the end of the slide rod 56 to prevent the slide rod 56 from detaching from the pressure plate 52. An adjusting bolt 53 is provided on the pressure plate 52 (bottom plate 54). The end of the bottom plate 53 is pressed against the bottom plate 54 (pressure plate 52). The adjusting bolt 53 is rotated to move the pressure plate 52 and the bottom plate 54 away from each other, and then the two-link structure 7 is slightly folded. The middle rotating shaft is pressed against the limit block 82 to prevent the sand-trapping cylinder 5 from shaking. If the bottom plate 53 is installed on the bottom plate 54, the filter screen at the bottom of the cylinder body 51 should be detachably connected. When tightening the bottom plate 53, the filter screen should be removed first, and then installed after tightening the bottom plate 53.

[0034] A gap is left between the cylinder 51 and the water spout 4 to facilitate the insertion of the sand-trapping tube 5 into the water spout 4, but mud and sand may enter the gap, preventing the sand-trapping tube 5 from being pulled out of the water spout 4. A closing bag 57 is provided at the lower end of the cylinder 51, and the cylinder 51 is connected to the bottom plate 54 through the front bag 55. When the bottom plate 53 is tightened, the pressure of the pressure plate 52 on the bottom plate 54 increases, and the bottom plate 54 is connected to the closing bag 57. The gas in the bottom plate 54 expands the closing bag 57 to block the gap between the side wall of the cylinder 51 and the water spout 4. When the two-link structure 7 is folded, the pressure plate 52 and the bottom plate 54 move away first, the pressure on the bottom plate 54 is reduced, the closing bag 57 retracts, and the sand-trapping tube 5 is easily pulled out.

[0035] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A geological drilling PDC drill bit, comprising a drill bit housing (1), the drill bit housing (1) being provided with a plurality of blades (2) and a mounting hole (3), a water nozzle (4) being installed in the mounting hole (3), a water cavity being provided in the drill bit housing (1), the water cavity being connected to a water pump, and characterized in that: A limit plate (6) is provided in the water cavity. The limit plate (6) is connected to a sand trap (5) with a filter screen at the bottom through a two-link structure (7). A limit structure for preventing the sand trap (5) from passing through the water nozzle (4) is provided on the upper part of the sand trap (5). The two-link structure (7) is composed of two links. The ends of the two links are connected through an intermediate rotating shaft. When the limit structure of the sand trap (5) is pressed against the end of the mounting hole (3), the intermediate rotating shaft of the two-link structure (7) is biased to one side. The drill housing (1) ) is provided with a limiter (8), which can limit the intermediate rotating shaft of the two-link structure (7) from continuing to move toward one side. The drill bit housing (1) is also provided with a telescopic member (9) and a driving structure. When going down the well, the telescopic member (9) remains in an extended state and contracts under the mud pressure during drilling. When the telescopic member (9) contracts, the limiter (8) is triggered to act, so that the limiter (8) releases the restriction on the intermediate rotating shaft of the two-link structure (7), and the driving structure drives the two-link structure (7) to continue to fold.

2. A geological drilling PDC drill bit according to claim 1, characterized in that: The telescopic member (9) comprises a telescopic chamber (91) and a telescopic rod (92); the telescopic rod (92) is connected to a limit block (82) via a connecting arm (81); the limit block (82) is arranged on a moving path of an intermediate rotating shaft of the two-link structure (7); the limit block (82) moves as the telescopic rod (92) contracts, and leaves the moving path of the intermediate rotating shaft after moving.

3. A geological drilling PDC drill bit according to claim 2, characterized in that: The driving structure is an elastic pull rope (10), and the two ends of the elastic pull rope (10) are respectively fixedly connected to the two ends of the two-link structure (7).

4. A geological drilling PDC drill bit according to claim 2, characterized in that: The driving structure is a lifting rod (83), which is fixedly connected to a connecting arm (81). The connecting arm (81) is located below the moving path of the intermediate rotating shaft. As the telescopic rod (92) continues to contract, the lifting rod (83) moves with the intermediate rotating shaft, causing the two-link structure (7) to fold.

5. A geological drilling PDC drill bit according to claim 3 or 4, characterized in that: The telescopic member (9) further comprises an air cavity (93) which is annular and is arranged on the limiting plate (6). The air cavity (93) is connected to the top of the telescopic cavity (91), and the telescopic cavity (91) and the air cavity (93) are filled with gas.

6. A geological drilling PDC drill bit according to claim 3 or 4, characterized in that: The sand-trapping cylinder (5) comprises a cylinder body (51) and a pressure plate (52), wherein the cylinder body (51) is fixedly connected to a bottom plate (54), the pressure plate (52) is connected to a limit plate (6), the bottom plate (54) is fixedly connected to a slide bar (56), the slide bar (56) is inserted into the pressure plate (52) and is slidably connected to the pressure plate (52), and an adjusting bolt (53) is provided on the pressure plate (52) or the bottom plate (54), and the pressure plate (52) and the bottom plate (54) can be moved away from each other by rotating the adjusting bolt (53).

7. A geological drilling PDC drill bit according to claim 6, characterized in that: A gap is left between the cylinder (51) and the water nozzle (4).

8. A geological drilling PDC drill bit according to claim 7, characterized in that: A closed capsule (57) is provided at the lower end of the cylinder (51); the cylinder (51) is connected to the bottom plate (54) via the front capsule (55); and the bottom plate (54) is in communication with the closed capsule (57).

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