PDC bit for impact and gouging combined rock breaking

Abstract

The application provides a PDC drill bit for impact and scraping combined rock breaking, comprising: a body with a rock breaking blade wing, the body is internally defined with a first channel for fluid flow; and an impact assembly, the impact assembly comprises an outer sleeve with a first inner cavity; and an impact tooth arranged in the first inner cavity. A second channel is formed between the impact tooth and the first inner cavity and is communicated with the first channel, fluid flowing through the second channel can generate an acting force for moving the impact tooth from a first position in the first inner cavity to a second position extending out of the body. Meanwhile, the impact assembly further comprises an elastic member capable of keeping the impact tooth in the first position. A power control assembly is further arranged in the first channel, the power control assembly is capable of periodically cutting off the communication between the first channel and the second channel.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil and gas exploration, and particularly relates to a PDC drill bit for impact scraping and cutting composite rock breaking. BACKGROUND

[0002] In recent years, the proportion of exploration and development of deep wells and ultra-deep wells in drilling operations is increasing. Due to the increase in hardness of deep strata, the conventional PDC drill bit has problems such as difficulty in eating into the strata and low mechanical drilling speed of PDC cutting teeth, which greatly reduces the drilling efficiency of deep oil and gas resources. If the eating depth and mechanical drilling speed of the PDC drill bit are improved by increasing the drilling pressure and speed on the ground, it is easy to cause problems such as PDC tooth wear, drill stick-slip vibration, and PDC tooth collapse failure, which not only restricts the further improvement of the mechanical drilling speed, but also greatly affects the service life of the drill bit.

[0003] In order to improve the rock breaking efficiency of the PDC drill bit and eliminate the stick-slip vibration phenomenon of the PDC drill bit, the existing technology is to install a rotary impact drilling tool, a torsional impactor or a composite impact tool on the PDC drill bit. The rock breaking efficiency and mechanical drilling speed of the PDC drill bit are improved by the impact cutting composite rock breaking method, and the ordered vibration is used to suppress the disordered vibration of the bottom hole assembly and the drill bit.

[0004] The existing various impact tools all provide a periodic high-frequency impact load to the whole drill bit to realize dynamic-static load coupling and improve the rock breaking efficiency of the PDC drill bit. This method of applying impact load to the whole PDC drill bit and then dispersing it to each PDC cutting tooth will cause insufficient impact force and impact rock breaking effect of PDC single tooth, and the speed increase in hard strata is not obvious.

[0005] At the same time, the structure of the existing various impactors is relatively complex, and the length of some tools can reach 2-5m, which consumes a lot of hydraulic energy of the drilling fluid and limits its application range. When the impactor is installed between the drill bit and the bent screw, it will also seriously affect the build-up rate of the drilling assembly, and is not suitable for use in directional drilling. SUMMARY

[0006] In view of the above technical problems, the present application aims to provide a PDC drill bit for impact scraping and cutting composite rock breaking. The drill bit structure of the present application is simple, and can effectively improve the impact rock breaking effect and service life of the PDC drill bit.

[0007] According to the present application, a PDC drill bit for impact and gouging combined rock breaking is provided, comprising: a body with rock breaking blades, the body defining a first channel for fluid flow therein; and an impact assembly comprising an outer sleeve with a first inner cavity; and an impact tooth disposed in the first inner cavity. A second channel is formed between the impact tooth and the first inner cavity, and the second channel is in communication with the first channel, and fluid flowing through the second channel can generate a force to move the impact tooth from a first position in the first inner cavity to a second position extending out of the body. Meanwhile, the impact assembly further comprises an elastic member capable of keeping the impact tooth in the first position.

[0008] In the first channel, a power control assembly is further disposed, which can periodically cut off the communication between the first channel and the second channel.

[0009] In a preferred embodiment, the power control assembly comprises a rotating power device disposed in the first channel, and a rotating ring sleeved on the rotating power device, the rotating power device being capable of rotating under the action of fluid to drive the rotating ring to rotate.

[0010] In a preferred embodiment, a fixing ring is further sleeved on the rotating ring, and the rotating ring and the fixing ring are each provided with at least one drainage hole in the circumferential direction, the drainage holes on the rotating ring and the fixing ring being in communication with the rotating power device and the second channel, respectively.

[0011] In a preferred embodiment, the rotating power device is provided as a helical blade.

[0012] In a preferred embodiment, a stepped portion is formed on the outer wall of the impact tooth, a fixing nut is disposed on the impact tooth outer wall away from the second channel, and the elastic member is disposed in a groove formed by the stepped portion and the fixing nut.

[0013] In a preferred embodiment, the second channel has an inlet section close to the first channel and a drainage section away from the first channel, and the width of the inlet section is greater than that of the drainage section.

[0014] In a preferred embodiment, one or more extension portions of the impact tooth extend into the second channel.

[0015] In a preferred embodiment, the body has a second inner cavity, and the impact assembly is disposed in the second inner cavity, and the impact tooth is configured to be located in the first inner cavity when in the first position.

[0016] In a preferred embodiment, when the impact tooth is in the second position, the included angle between the impact tooth and the drill bit axis is in the range of 0°-90°.

[0017] In a preferred embodiment, the impact teeth are provided in the form of conical teeth, axe-shaped teeth or ball-shaped teeth, and are made of cemented carbide or polycrystalline diamond. BRIEF DESCRIPTION OF DRAWINGS

[0018] The present application will be described below with reference to the accompanying drawings.

[0019] Figure 1 A schematic view of a PDC drill bit for impact and gouging combined rock breaking according to the present application is shown.

[0020] Figure 2 For Figure 1 A top view of a rotating ring and a fixed ring of the PDC drill bit 100 for impact and gouging combined rock breaking is shown.

[0021] Figure 3 For Figure 1 A schematic view of an impact assembly of the PDC drill bit 100 for impact and gouging combined rock breaking is shown.

[0022] In the present application, all the drawings are schematic drawings and are only used to illustrate the principles of the present application, and are not drawn to scale. DETAILED DESCRIPTION

[0023] The present application will be described below with reference to the accompanying drawings.

[0024] Figure 1 A PDC drill bit 100 for impact and gouging combined rock breaking according to an embodiment of the present application is shown. As Figure 1 The PDC drill bit 100 for impact and gouging combined rock breaking includes a body 10. A joint 12 is provided on a first end 11 of the body 10, by which the body 10 is connected to a drill pipe (not shown) and is lowered into an oil well together with the drill pipe. A plurality of rock-breaking blades 16 are provided on a second end 13 of the body 10, and a plurality of cutting teeth 161 are uniformly arranged on each of the rock-breaking blades 16. The rock-breaking blades 16 rotate to drive the cutting teeth 161 to perform rock breaking. This structure is well known to those skilled in the art, and detailed description thereof is omitted here.

[0025] A first passage 18 for fluid flow is defined in the body 10, as Figure 1 shown. The fluid can be, for example, drilling fluid or high-pressure gas. Meanwhile, an impact assembly 20 is connected to the body 10. The impact assembly 20 includes impact teeth 21 and a sleeve 22 sleeved on the impact teeth. The sleeve 22 has a first inner cavity 221 in the form of a cylinder. A first end 222 of the first inner cavity 221 has an opening 223. The impact teeth 21 are arranged in the first inner cavity 221.

[0026] Meanwhile, a first gap 225 is formed between the second end 224 of the first inner cavity 221 and the axial direction of the impact tooth 21, and the two ends of the first gap 225 are connected with the first channel 18 respectively, so that the first gap 225 forms a second channel 226 for fluid flow in communication with the first channel 18. The fluid can be drilling fluid, high-pressure gas, etc.

[0027] It is easy to understand that when the high-pressure fluid flows along the radial direction of the first inner cavity 221 through the second channel 226, a pressure perpendicular to the second channel 226 will be formed on the side wall of the second channel 226. Under the driving of this pressure, the impact tooth 21 will move along the axial direction of the first inner cavity 221 from the first position in the first inner cavity to the second position extending out of the opening 223. The greater the pressure is, the greater the displacement of the impact tooth 21 moving along the axial direction of the first inner cavity 221 is.

[0028] Meanwhile, the impact assembly 20 further comprises an elastic member 211 capable of keeping the impact tooth 21 in the first position. The elastic member 211 can be a spring or a disc spring with different elastic stiffness, for example. Specifically, a stepped portion 212 is configured on the outer wall of the impact tooth, and a fixing nut 214 is arranged on the outer wall of the impact tooth away from the second channel 226. The elastic member 211 is arranged in a groove 215 formed by the stepped portion 212 and the fixing nut 214.

[0029] As shown in Figure 1 The fixing nut 214 is fixedly connected to the side wall of the first inner cavity 221, so that the fixing nut 214 can seal the opening 223 in cooperation with the impact tooth 21. The high-pressure fluid in the second channel 226 is prevented from flowing out of the first inner cavity 221 through the opening 223, so that the second channel 226 is depressurized.

[0030] The elastic member 211 is arranged in a natural state or a suitable pre-compressed state when the impact tooth 21 is in the first position. When the impact tooth 21 moves towards the opening 223 under the driving pressure of the fluid in the second channel 226, the stepped portion 212 will move towards the fixing nut 214, and at this time, the length of the groove 215 is reduced, and the elastic member 211 is in a further compressed state.

[0031] When no fluid flows through the second channel 226, since the fixing nut 214 remains stationary, the compressed elastic element 211 will push the stepped portion 212 away from the fixing nut 214 until the elastic element 211 returns to its natural, unforced state or a suitable pre-compressed state. At this time, the impact tooth 21 returns to its first position under the pull of the elastic element 211.

[0032] In summary, when high-pressure fluid flows through the second channel 226, the impact tooth 21 moves from the first position to the second position; and when no high-pressure fluid flows through the second channel 226, the impact tooth 21 returns from the second position to the first position. Therefore, it is easy to understand that by controlling the periodic flow of high-pressure fluid through the second channel 226, the reciprocating motion of the impact tooth 21 between the first and second positions can be controlled.

[0033] Meanwhile, by setting the impact tooth 21 to extend out of the first inner cavity 221 and contact the rock at the bottom of the well when it is in the second position, the impact tooth 21 can be controlled to continuously impact the rock at the bottom of the well, thereby producing the effect of impact rock breaking.

[0034] In a preferred embodiment, a second inner cavity 19 communicating with the first channel 18 is provided within the body 10. The impact assembly 20 is disposed within the second inner cavity 19. Simultaneously, the impact tooth 21 is configured to retract into the first inner cavity 221 when in the first position. This configuration minimizes the volume of the PDC drill bit 100, achieving a simplified structure.

[0035] In addition, the PDC drill bit 100 for impact scraping and rock breaking also includes a power control component 30 disposed in the first channel 18. The power control component 30 can periodically cut off the connection between the first channel 18 and the second channel 226, thereby controlling the high-pressure fluid in the first channel 18 to periodically flow through the second channel 226, thereby achieving the purpose of controlling the impact tooth 21 to reciprocate between the first position and the second position.

[0036] Specifically, such as Figure 1 As shown, the power control assembly 30 includes a rotary power device 31 disposed within the first channel 18. A rotating ring 32 is fitted onto the outer wall of the rotary power device 31 near the second channel 226. The rotary power device 31 can rotate under the action of an external force and drive the rotating ring 32 to rotate synchronously. Simultaneously, a fixing ring 33 is also fitted onto the rotating ring 32.

[0037] In the present application, the rotating power device 31 is preferably provided as a helical blade. The helical blade can rotate under the action of liquid pressure without the need to introduce other power generation devices.

[0038] Figure 2 For Figure 1 The top view of the rotating ring 32 and the fixed ring 33 of the PDC drill bit 100 for impact and scraping combined rock breaking is shown. As Figure 2 The rotating ring 32 and the fixed ring 33 have similar structures, and at least one drainage hole 321 is provided on the circumference of the rotating ring 32 and the fixed ring 33, as shown.

[0039] In the present application, since the fixed ring 33 is always in a fixed state without rotation, when the rotating ring 32 rotates synchronously with the rotation of the rotating power device 31, the drainage holes 321 on the rotating ring 32 and the fixed ring 33 will be periodically communicated and staggered.

[0040] When the drainage holes 321 on the rotating ring 32 and the fixed ring 33 are communicated, the first channel 18 and the second channel 226 remain communicated, and the high-pressure fluid in the first channel 18 can pass through the rotating power device 31 and the drainage hole 321 in turn to reach the second channel 226, and generate pressure on the impact tooth 21, so that the impact tooth 21 moves from the first position to the second position against the elastic force of the elastic member 211.

[0041] When the drainage holes 321 on the rotating ring 32 and the fixed ring 33 are staggered, the communication between the first channel 18 and the second channel 226 is cut off, and at this time there is no high-pressure fluid flowing into the second channel 226, and the impact tooth 21 returns to the first position under the action of the elastic force of the elastic member 211.

[0042] In summary, as long as the rotating power device 31 is controlled to keep rotating under the action of external force, the impact tooth 21 can be controlled to reciprocate between the first position and the second position, thereby generating the effect of impact rock breaking.

[0043] Figure 3 For Figure 1 The schematic diagram of the impact assembly 20 of the PDC drill bit 100 for impact and scraping combined rock breaking is shown. As Figure 3As shown, the second channel 226 is divided into a liquid inlet section 227 close to the rotary power device 31 and a liquid outlet section 228 away from the rotary power device 31, and the width of the liquid inlet section 227 is set to be greater than that of the liquid outlet section 228. By such an arrangement, when the high-pressure fluid flows through the second channel 226, a pressure build-up phenomenon can be generated, thereby facilitating an increase in the driving pressure of the fluid and an increase in the speed and impact force of the impact teeth 21.

[0044] Meanwhile, in a preferred embodiment, one or more extensions 213 of the impact teeth 21 are arranged to extend into the second channel 226. The extensions 213 can be arranged in a cylindrical or prismatic shape, for example. The extensions 213 can hinder the high-pressure fluid from flowing through the second channel 226 to some extent, thereby further increasing the pressure of the high-pressure fluid on the impact teeth 21 and increasing the speed and impact force of the impact teeth 21.

[0045] In addition, the impact teeth 21 are preferably made of cemented carbide or polycrystalline diamond. These materials can be widely used in different working conditions of the formation, thereby facilitating an increase in the application range of the impact and scraping composite rock-breaking PDC drill bit 100. Similarly, the impact teeth 21 can be configured in a conical tooth, an axe-shaped tooth or a spherical tooth, so that different tooth shapes can be selected for different formation conditions, thereby increasing the application range of the impact and scraping composite rock-breaking PDC drill bit 100.

[0046] As shown in FIG. 2, the impact teeth 21 are arranged on the body 10 of the drill bit 100 in a staggered manner. Figure 1 As shown, in a preferred embodiment, when the impact teeth 21 are in the second position, the included angle 40 between the impact teeth 21 and the drill bit axis is set to be in the range of 0°-90°. Field practice shows that in this angle range, the impact teeth have a better effect on rock breaking and drilling.

[0047] The following is a brief description of the working process of the impact and scraping composite rock-breaking PDC drill bit 100 according to the present application.

[0048] The impact and scraping composite rock-breaking PDC drill bit 100 according to the present application is connected to the drill pipe through the joint 12, and is lowered into the oil well together with the drill pipe, and rock breaking is achieved by rotating the cutting teeth 161 driven by the rock-breaking blade 16. At the same time of rock breaking, high-pressure downhole fluid (such as drilling fluid) flows into the first channel 18 in the body 10. Then, the high-pressure fluid in the first channel 18 flows to the rotary power device 31 to drive the rotary power device 31 to rotate.

[0049] The rotation of the rotating power device 31 drives the rotation of the rotating ring 32. At this time, with the rotation of the rotating ring 32, the liquid discharge holes 321 on the rotating ring 32 and the fixed ring 33 are periodically communicated and disengaged, causing the periodic communication between the first channel 18 and the second channel 226, and the high-pressure fluid in the first channel 18 periodically enters the second channel 226.

[0050] When the high-pressure fluid enters the second channel 226, the impact teeth 21 move from the first position to the second position against the elastic force of the elastic member 211 under the driving pressure of the high-pressure fluid, and impact the bottom rock. When the high-pressure fluid does not enter the second channel 226, the impact teeth 21 return to the first position under the elastic force of the elastic member 211.

[0051] With the continuous rotation of the rotating power device 31, the impact teeth 21 continuously reciprocate between the first position and the second position, and impact the bottom rock. In this way, on the one hand, the drilling efficiency is improved, and on the other hand, the regular and periodic vibration impact in the drill bit body suppresses the disordered stick-slip vibration of the rock-breaking PDC drill bit 100, avoids the collapse of the PDC drill bit, and prolongs the service life of the drill bit.

[0052] Finally, it should be noted that the above description is only a preferred embodiment of the present application and does not constitute any limitation on the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or replace some technical features with equivalent ones. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A PDC bit for impact and gouging combined rock breaking, comprising: a body (10) having a rock breaking blade (16), the body defining a first passage (18) for fluid flow therein, and an impact assembly (20) including a sleeve (22) having a first inner cavity (221), and an impact tooth (21) disposed in the first inner cavity, a second passage (226) being formed between the impact tooth and the first inner cavity, the second passage being in communication with the first passage, fluid flowing through the second passage being capable of generating a force to move the impact tooth from a first position in the first inner cavity to a second position extending out of the body, the impact assembly further including a resilient member (211) capable of retaining the impact tooth in the first position, wherein a power control assembly (30) is further disposed in the first passage, the power control assembly being capable of periodically cutting off the communication between the first passage and the second passage, the power control assembly including: a helical vane disposed in the first passage, a rotating ring (32) sleeved on the helical vane, the helical vane being rotatable under the action of fluid to drive the rotating ring to rotate, and a fixed ring (33) sleeved on the rotating ring, the rotating ring and the fixed ring each being provided with at least one drainage hole (321) in the circumferential direction, the drainage holes on the rotating ring and the fixed ring being in communication with the helical vane and the second passage respectively, wherein the fluid in the first passage is capable of rotating the helical vane, and thereby driving the rotating ring to rotate, so that the drainage holes on the rotating ring and the fixed ring are periodically in communication and out of communication, resulting in the first passage and the second passage being periodically in communication, and resulting in the fluid in the first passage being capable of periodically entering the second passage to drive the impact tooth to move from the first position to the second position, wherein the impact tooth is further provided with one or more extensions (213) extending into the second passage, the second passage including an inlet section (227) close to the first passage and a drainage section (228) away from the first passage, the inlet section and the drainage section being located on two sides of the extension respectively, wherein the width of the inlet section is greater than that of the drainage section.

2. The impact gouging and chipping combined rock-breaking PDC bit according to claim 1, characterized in that, a step portion (212) is formed on the outer wall of the impact tooth, a fixed nut (214) is disposed on the impact tooth outer wall away from the side of the second passage, and the resilient member is disposed in a groove (215) formed by the step portion and the fixed nut.

3. The impact gouging and chipping combined rock-breaking PDC bit according to claim 1 or 2, characterized in that, the body has a second inner cavity (19), and the impact assembly is disposed in the second inner cavity, the impact tooth is configured to be located in the first inner cavity when in the first position.

4. The impact gouging and chipping combined rock-breaking PDC bit according to claim 1 or 2, characterized in that, when the impact tooth is in the second position, the impact tooth is arranged to have an angle with the bit axis in the range of 0°-90°.

5. The impact gouging and chipping combined rock-breaking PDC bit according to claim 1 or 2, characterized in that, the impact tooth is arranged to be a conical tooth, an axe-shaped tooth or a spherical tooth, and the impact tooth is made of cemented carbide or polycrystalline diamond.

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