CN101942967A - Bit hydraulic structure capable of reducing pressure and accelerating speed and drilling bit - Google Patents

Abstract

The invention relates to a drill bit hydraulic structure and a drill bit for reducing pressure and increasing speed, and belongs to the field of petroleum and geological drilling engineering. The hydraulic structure of the drill bit is composed of the drill bit body, the main flow channel, the transition zone of the flow channel, the water hole, the ring groove, the sealing groove and the erosion-resistant layer. It is characterized in that: the main flow channel, the flow channel transition zone and the water hole are located in the drill body, the flow channel transition zone is connected to the main channel and the water hole, the axis of the flow channel transition zone and the water hole is perpendicular to the axis of the main channel, and the ring groove and the seal The groove is located in the water hole, and the erosion-resistant layer is located on the surface of the transition zone of the flow channel. The angle between the outlet direction of the drill bit water hole and the axis of the drill bit is 90°, and the angle between the direction of the drill bit and the radial direction is 0°~90°. The mud shoots obliquely to the well wall. Driven by the rotational speed of the drill bit and the tangential speed of the mud itself, A low-pressure vortex area is formed at the bottom of the well, which reduces the local pressure of the drill bit’s active surface and reduces the holding effect of the mud column on the cuttings. The drilling fluid pumps the cuttings at the bottom of the well, accelerates the removal of cuttings, increases the drilling speed, and reduces drilling costs. .

Description

Drill bit hydraulic structure and drill bit for decompression and speed increase

Technical field

The invention relates to the fields of petroleum and geological drilling engineering, in particular to a drill bit hydraulic structure and a drill bit for reducing pressure and increasing speed.

Background technique

In order to exploit underground oil and gas resources, it is necessary to use drilling tools to drill through underground formations. These drilling tools generally include a derrick, a rotary table, a kelly, a drill pipe, a drill collar and a drill bit from the surface to the ground. The drill bit cuts through the formation to drill the wellbore. When the drill bit cuts the formation, a large amount of cuttings are produced at the bottom of the well. In order to remove these cuttings to the surface, drilling fluid must be injected through the inside of the drill string while drilling. The drilling fluid is ejected from the drill bit and passes through the drill string and the formation. The annular space between returns to the surface, thus carrying the cuttings to the surface. However, the drilling fluid produces a very large fluid column holding force on the bottom of the well. For example, for a 3,000-meter-deep wellbore, the drilling fluid with a density of 1.1g/cm ³ is used to drill, and the pressure will reach 33MPa. The outlet of the water hole of the existing drill bit is downward along the well depth direction, and the included angle with the axis of the drill bit is 0°~60°. After the drilling fluid flows through the nozzle, it directly hits the bottom of the well. The cuttings are held at the bottom of the well, which is not conducive to the removal of cuttings and greatly reduces the efficiency of cuttings removal. Especially in the drilling process of deep and ultra-deep wells, the huge holding force of the drilling fluid column will greatly affect the timely removal of cuttings, resulting in repeated breakage of the drill bit and reducing the drilling speed.

In order to solve this problem, people usually increase the displacement of the mud pump, increase the pump pressure, use various nozzle combinations and change the nozzle structure, rely on high-pressure water jets to increase the impact on the bottom of the well, and realize the combination of water jets and machinery. rock. However, this method increases the holding force of the mud column on the cuttings at the bottom of the well, especially in deep and ultra-deep well drilling. Not obvious. Therefore, there is an urgent need for a drill bit that can reduce the local pressure at the bottom of the wellbore. Under the condition of keeping the mud column pressure of the whole wellbore constant, the mud column pressure on the working surface of the drill bit can be reduced, thereby greatly improving the mechanical strength while maintaining the stability of the wellbore wall. Drilling speed.

Contents of the invention

The purpose of the present invention is to overcome the deficiencies in the prior art and provide a drill bit hydraulic structure and a drill bit that can reduce the mud column holding force on the active surface of the bottom hole drill bit to increase the drilling speed.

The technical scheme adopted by the present invention to solve the above-mentioned technical problems is: a drill bit hydraulic structure for decompression and speed increase includes main flow channel, drill bit body, flow channel transition zone, water hole, circlip groove, sealing groove and erosion-resistant layer. The main flow channel, the flow channel transition area and the water hole are located in the drill body; the flow channel transition area communicates with the main flow channel and the water hole; the flow channel transition area and the water hole The axis is perpendicular to the axis of the main flow channel; the circlip groove and the sealing groove are located in the water hole; the erosion-resistant layer is located on the surface of the transition zone of the flow channel.

The main flow channel is cylindrical, and its axis coincides with the axis of the drill bit body; the upper end of the main flow channel is connected with the drilling fluid channel in the drill string, and the lower end is connected with the flow channel transition zone.

The flow channel transition zone includes a conical constriction section, a turning and bending section and an upward diverging section; the conical constricting section is conical; the turning and bending section is arc-shaped, and its arc center is on one side of the drill bit rotation direction; The upward diffusion section is cylindrical, connected to the water hole, and its centerline coincides with the centerline of the water hole.

The water hole is cylindrical, and its outlet direction is consistent with the drill bit rotation direction; the angle α between the outlet direction of the water hole and the drill bit axis is 90°; the radial direction where the central point of the water hole outlet is located, The included angle with the axis of the water hole is β: 0°<β<90°.

The circlip groove is located at the inner upper end of the water hole, and is used for placing a circlip to fix the drill nozzle in the water hole.

The sealing groove is located in the middle of the water hole and is used to place a sealing device to prevent the mud from leaking from the gap between the nozzle and the water hole; the sealing device adopts an "O" type sealing ring and an expansion sealing structure.

The erosion-resistant layer adopts the method of oxyacetylene or laser cladding, and the erosion-resistant material is welded on the surface of the flow channel transition zone, and the thickness of the welding is 0.2-2.0mm.

The decompression-speed-up drill bit uses a decompression-speed-up drill bit hydraulic structure, and several identical flow channel transition zones and water holes can be set in the drill bit body at the same time.

In the present invention, the outlet direction of the water hole of the existing drill bit is adjusted from 0° to 60° to the axis of the drill bit to an angle of 90° to the axis of the drill bit, and to an angle of 0° to 90° to the radial direction of the drill bit. . After the mud flows through the nozzle, it changes from the original downward direction directly to the bottom of the well to the horizontal direction, and obtains a velocity tangential to the well wall. Combined with the driving effect of the drill bit rotation speed, after the mud is ejected from the water hole, it makes a circular motion with the drill bit, forming a vortex near the drill bit, and a low-pressure area is generated at the bottom of the vortex, thereby reducing the holding force of the mud column at the bottom of the well. Bottomhole cuttings are swabbed away from the bottom of the well under the action of the pressure difference between the upper and lower sides, and return to the surface with the drilling fluid. On the one hand, the drill bit of the present invention generates a local low-pressure vortex area at the bottom of the well, which reduces the holding effect of cuttings at the bottom of the well, realizes the swabbing of cuttings at the bottom of the well, accelerates the removal of cuttings, and reduces the repetition of cuttings. On the other hand, because there is no need for high-power mud pumps and diesel engines, the drilling cost is reduced and energy is saved.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a vertical sectional view of the present invention.

Fig. 2 is a cross-sectional view of the hydraulic structure of the drill bit of the present invention.

Fig. 3 is a vertical sectional view of the tooth palm of a tricone bit according to an embodiment of the present invention.

Fig. 4 is a cross-sectional view of the hydraulic structure of the tri-cone bit according to an embodiment of the present invention.

Fig. 5 is a vertical sectional view of a PDC drill bit according to an embodiment of the present invention.

Fig. 6 is a cross-sectional view of the hydraulic structure of a PDC drill bit according to an embodiment of the present invention.

Detailed ways

Embodiment 1: The following will be described in conjunction with Fig. 1 and Fig. 2 . The present invention includes a main flow channel 1, a drill bit body 2, a flow channel transition zone 3, a water hole 4, a ring groove 5, a sealing groove 6 and an erosion-resistant layer 7, the main flow channel 1, the flow channel transition zone 3 and the The water hole 4 is located in the drill bit body 2; the flow channel transition zone 3 communicates with the main channel 1 and the water hole 4; the axis of the flow channel transition zone 3 and the water hole 4 is perpendicular to The axis of the main flow channel 1 ; the snap ring groove 5 and the sealing groove 6 are located in the water hole 4 ; the erosion-resistant layer 7 is located on the surface of the flow channel transition zone 3 . The main flow channel 1 is cylindrical, connected with the drilling fluid channel in the drill string at the top, and connected with the transition zone 3 of the flow channel at the bottom. The flow channel transition zone 3 includes a conical constriction section 8, a turning and bending section 9 and an upward diverging section 10; the conical constricting section 8 is conical; the turning and bending section 9 is arc-shaped, and its arc center is at One side of the drill bit rotation direction; the upward diffusion section 10 is cylindrical, connected to the water hole 4 , and its centerline coincides with the centerline of the water hole 4 . The water hole 4 is cylindrical, and its outlet direction is consistent with the drill bit rotation direction; the angle α between the outlet direction of the water hole 4 and the drill bit axis is 90°; the diameter of the center point at the outlet of the water hole 4 In the direction, the included angle with the axis of the water hole 4 is β: 0°<β<90°. The circlip groove 5 is located at the inner upper end of the water hole 4 and is used for placing a circlip to fix the drill nozzle in the water hole 4 . The sealing groove 6 is located in the middle of the water hole 4, and is used to place a sealing device to prevent the mud from leaking from the outside of the nozzle and the inner surface of the water hole 4; the sealing device adopts an "O" type sealing ring and an expansion seal structure. The erosion-resistant layer 7 is oxyacetylene or laser cladding method, and the erosion-resistant material is welded on the surface of the flow channel transition zone 3, and the thickness of the welding is 0.2-2.0mm.

Embodiment 2: It will be described below in conjunction with accompanying drawing 3 and accompanying drawing 4. A three-cone bit for decompression and speed-up is composed of palm 11, cone 12, main flow channel 1, flow channel transition area 3, water hole 4, ring groove 5, sealing groove 6 and erosion-resistant layer 7. The channel transition zone 3 is composed of a tapered constriction section 8 , a turning bend section 9 and an upward diverging section 10 . Three identical flow channel transition areas 3 and water holes 4 are distributed symmetrically at 120° in the same plane inside the drill body 2 , and this plane is perpendicular to the axis of the main flow channel 1 . When they are not in the same plane, the distances between the flow channel transition zones 3 and the water holes 4 of each group are the same from the horizontal plane of the well bottom. In the drawings, the direction indicated by the solid arrow is the flow direction of the mud in the drill bit.

Its working principle: the drill string drives the three-cone bit to rotate, and the cone 12 rotates to break the bottom rock; the drilling fluid enters the main channel 1 inside the tooth palm 11 from the drill string, and flows through the conical contraction section of the flow channel transition zone 3 8. When the speed increases and the pressure decreases, the drilling fluid flows through the turning and bending section 9, and the velocity direction gradually transitions from the initial radial direction to the rotation direction of the drill bit until an included angle β is formed, and then flows through the upward diffusion section 10. During this process, the drilling fluid acquires a velocity tangential to the well wall; the drilling fluid shoots obliquely from the nozzle in the water hole 4 to the well wall, and the pressure of the drilling fluid at the outlet of the water hole 4 increases rapidly, and the upward flow carries While the cuttings are rapidly flowing towards the wellbore, under the effect of tangential velocity, they make a circular motion around the wellbore axis. At this time, a large vortex appears between the outer surface of the bit body 2 and the annulus of the wellbore wall, and at the bottom of the vortex That is, a low-pressure area is generated at the bottom of the well, and the pressure holding force of the mud column at the bottom of the well is reduced, and it is drawn away from the bottom of the well and returns to the surface with the drilling fluid. The erosion-resistant layer 7 is deposited and welded on the surface of the flow passage transition zone 3 by using an erosion-resistant material, so as to improve the erosion resistance of the flow passage transition zone 3 under the erosion of high-speed drilling fluid and improve the service life of the drill bit.

Embodiment 3: It will be described below in conjunction with accompanying drawing 5 and accompanying drawing 6. A pressure-reducing and speed-increasing PDC drill bit consists of a drill body 2, a flow channel 1, a flow channel transition zone 3, a water hole 4, a ring groove 5, a sealing groove 6, an erosion-resistant layer 7, a blade 13 and a synthetic diamond composite sheet- Composition of PDC14. The channel transition zone 3 is composed of a tapered constriction section 8 , a turning bend section 9 and an upward diverging section 10 . According to needs, 1-10 groups of the same flow channel transition zone 3 and water hole 4 can be set in the drill body 2. In this embodiment, 4 groups of the same flow channel transition zone 3 and water hole 4 are used, which are symmetrically distributed at 90°. In the same plane inside the drill body 2, and this plane is perpendicular to the axis of the main flow channel 1. The distances of each group of the flow channel transition zone 3 and the water hole 4 from the horizontal plane of the bottom of the well can be the same or different. The distance between the transition zone 3 and the water hole 4 from the horizontal plane of the well bottom is the same.

Its working principle: the drill string drives the PDC bit to rotate, and the synthetic diamond composite sheet-PDC14 on the blade 13 rotates to scrape the rock at the bottom of the well; the drilling fluid enters the main channel 1 inside the drill body 2 from the drill string, and flows through the flow channel transition In the conical contraction section 8 of zone 3, the speed increases and the pressure decreases, and flows through the turning and bending section 9, and the velocity direction gradually transitions from the initial radial direction to the rotation direction of the drill bit until an included angle β is formed, and then flows through the upward In the diffusion section 10, the pressure of the drilling fluid increases, and during this process, the drilling fluid obtains a velocity tangential to the well wall; the drilling fluid shoots obliquely from the nozzle in the water hole 4 to the well wall, and the pressure of the drilling fluid at the outlet of the water hole 4 Rapidly increasing, while the upward flow carries the cuttings to the direction of the wellbore, at the same time, under the action of the tangential velocity, it makes a circular motion around the wellbore axis. At this time, a A large vortex creates a low-pressure area at the bottom of the vortex, that is, the bottom of the well, and the holding force of the mud column at the bottom of the well decreases. At the bottom of the well, it returns to the surface with the drilling fluid. The erosion-resistant layer 7 is deposited and welded on the surface of the flow channel transition zone 3 by using an erosion-resistant material to improve the erosion resistance of the flow channel transition zone 3 under high-speed drilling fluid erosion and improve the service life of the drill bit.

Claims (10)

1. A drill bit hydraulic structure for decompression and speed increase, comprising a drill bit body (2), a main flow channel (1), a flow channel transition zone (3), a water hole (4), a circlip groove (5), a sealing groove (6) ) and erosion-resistant layer (7), characterized in that: the main flow channel (1), the flow channel transition zone (3) and the water hole (4) are located in the drill bit body (2), the The channel transition zone (3) communicates with the main channel (1) and the water hole (4), and the axes of the channel transition zone (3) and the water hole (4) are perpendicular to the main channel (1), the circlip groove (5) and the sealing groove (6) are located in the water hole (4), and the erosion-resistant layer (7) is located in the flow channel transition zone (3) ) surface; the main channel (1) is cylindrical, and its axis coincides with the axis of the drill bit body (2); the upper end of the main channel (1) is connected with the drilling fluid channel in the drill string, and its lower end is connected with the drilling fluid passage in the drill string. The flow channel transition zone (3) is connected; the flow channel transition zone (3) includes a conical constriction section (8), a turning bend section (9) and an upward diffusion section (10); the conical constriction section (8) is Conical; the turning and bending section (9) is arc-shaped, and its arc center is on one side of the drill bit rotation direction; the upward diffusion section (10) is cylindrical, connected with the water hole (4), and its The center line coincides with the center line of the water hole (4); the water hole (4) is cylindrical, and its outlet direction is consistent with the drill bit rotation direction; the angle α between the outlet direction of the water hole (4) and the drill bit axis is 90°; the radial direction where the central point of the outlet of the water hole (4) is located, and the included angle with the axis of the water hole (4) is β: 0°<β<90°. 2. The hydraulic structure of a drill bit for decompression and speed-up according to claim 1, characterized in that: the circlip groove (5) is located at the inner upper end of the water hole (4) for placing a circlip so that the drill bit nozzle fixed in the water hole (4). 3. The drill bit hydraulic structure for decompression and speed-up according to claim 1, characterized in that: the sealing groove (6) is located in the middle position inside the water hole (4), and is used to place a sealing device, and the sealing groove (6) The device adopts "O" type sealing ring and expansion sealing structure. 4. The hydraulic structure of a drill bit for decompression and speed-up according to claim 1, characterized in that: the erosion-resistant layer (7) adopts oxyacetylene, laser cladding or plasma arc welding, and the erosion-resistant material is deposited and welded On the surface of the flow channel transition zone (3), the welding thickness is 0.2-2.0 mm. 5. A drill bit for decompression and speed-up, this drill bit is a three-cone drill bit, and there are three tooth palms (11) and roller cones (12) on the drill bit body (2), which are characterized in that: comprise the According to the hydraulic structure of the drill bit, three groups of the same flow channel transition zone (3) and the water hole (4) are symmetrically distributed in the drill bit body (2) at 120°. 6. The drill bit for decompression and speed-up according to claim 5, characterized in that: each group of the flow channel transition zone (3) and the water hole (4) are in the same plane. 7. The drill bit for decompression and speed-up according to claim 5, characterized in that: each group of said flow channel transition zone (3) and said water hole (4) are not in the same plane, each group of said flow channel The distance between the channel transition zone (3) and the water hole (4) from the horizontal plane of the well bottom is the same. 8. A drill bit for decompression and speed-up, the drill bit is a PDC drill bit, and the drill bit body (2) has a synthetic diamond composite sheet-PDC (14) for crushing rock, it is characterized in that: comprise the drill bit hydraulic structure described in claim 1 , 1 to 10 groups of the same flow passage transition zone (3) and the water hole (4) can be set in the drill bit body (2) at the same time, each group of the flow passage transition zone (3) and the The water holes (4) are symmetrically distributed in the drill bit body (2) along the circumference. 9. The decompression and speed-up drilling bit according to claim 8, characterized in that: the distances from the flow channel transition zone (3) and the water hole (4) of each group to the horizontal plane at the bottom of the well are the same 10. The pressure reducing and speed increasing drill bit according to claim 8, characterized in that: the distances between each group of the flow channel transition zone (3) and the water hole (4) are different from the horizontal plane at the bottom of the well, and each adjacent The distance between the passage transition zone (3) and the water hole (4) is the same for each group or every two groups and every three groups.

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