A type of directional drilling tool for fractured strata

Abstract

This invention discloses a directional drilling tool for fractured strata, comprising a directional drill bit, a single-bend screw motor, a measurement-while-drilling (MWD) probe, an unsticking device, and a directional drill rod connected in sequence. The unsticking device includes an unsticking shell with a hollow channel and multiple unsticking mechanisms distributed circumferentially on the unsticking shell. The unsticking shell includes a stepped section in the middle and circular tube sections on both sides of the stepped section. The two sides of the stepped section are sloped, and the circular tube sections are provided with a spiral groove structure. The unsticking mechanisms include reaming cutting teeth. By setting up the unsticking device, the reaming cutting teeth are extended using the water pressure of high-pressure flushing fluid, which facilitates the reaming of the borehole when the drill bit is stuck, forming an reamed section. The spiral groove structure conveys the coal and rock blocks causing the drill bit to get stuck to the stepped section, while simultaneously crushing and pulverizing the coal and rock blocks. High-pressure water sprayed from the inclined channel performs water cutting on the coal and rock blocks. Harder coal and rock blocks cannot be fully crushed and enter the reamed section, thereby achieving the unsticking of the directional drill bit.

Description

Technical Field

[0001] This invention relates to the field of underground tunnel drilling technology in coal mines, and in particular to a directional drilling tool for fractured strata. Background Technology

[0002] The challenge of mining lower coal seams is to "protect the deep Ordovician limestone confined water while ensuring safe mining." Currently, the common approach is to reinforce the coal mine by grooving after directional drilling.

[0003] When drilling near-directionally in fractured coal seams or rock formations, especially during near-horizontal directional drilling, drill bit jamming or burial accidents are prone to occur. These mainly include drill bit jamming due to hole collapse, drill bit jamming due to mudstone narrowing, and drill bit jamming due to drill cuttings deposition. Among these, drill bit jamming due to hole collapse is a relatively frequent type of in-hole accident. It is caused by the instability and collapse of local rock mass in the borehole wall, which jams the drill bit, causing the rotation and tripping of the drill bit to be obstructed.

[0004] Existing technologies generally employ two methods to handle stuck drill bits or burial accidents: force-operated retrieval and milling-out retrieval. Force-operated retrieval combines rapid changes in forward rotation speed with quick tripping and retrieval, causing the drill string at the stuck point to compress and crush the collapsed debris, thus loosening the drill string and releasing it from the stuck position. However, for larger and harder coal and rock blocks generated during borehole collapse, the shallow auger grooves (typically only 3-5mm) of the auger pipe structure are insufficient to effectively crush and break up these blocks. As drill cuttings accumulate in the borehole, abnormal increases in parameters such as drilling pressure and mud pump pressure occur, making normal construction impossible. Furthermore, the drill string is prone to fatigue failure, increasing the complexity of accident handling and reducing drilling safety. Milling-out retrieval, on the other hand, suffers from low efficiency and long drilling cycles when handling stuck drill bits. Summary of the Invention

[0005] Therefore, it is necessary to provide a directional drilling tool for fractured strata to address the aforementioned technical problems.

[0006] To achieve the above objectives, the present invention provides a directional drilling tool for fractured formations, comprising a directional drill bit, a single-bend screw motor, a measurement-while-drilling probe, a detachment device, and a directional drill rod connected in sequence. The card-unlocking device includes a card-unlocking housing with a hollow channel and multiple card-unlocking mechanisms distributed circumferentially on the card-unlocking housing. The card-unlocking housing includes a stepped section in the middle and circular tube sections on both sides of the stepped section. The two sides of the stepped section are sloped, and the circular tube sections are provided with a spiral groove structure. The unblocking mechanism includes a hydraulic chamber, an unblocking chamber, a hydraulic channel, and an oblique injection channel disposed within the stepped portion. The hydraulic chamber is connected to the hollow channel. A piston is slidably sealed and installed within the hydraulic chamber. A first spring is installed within the hydraulic chamber and connected to the piston. A one-way resistance valve is installed on the side of the hydraulic chamber away from the center of the stepped portion, and the one-way resistance valve is connected to the unblocking chamber through the hydraulic channel. An outer sliding sleeve is slidably sealed and installed within the unblocking chamber. An inner slider is slidably sealed and installed within the outer sliding sleeve. A hole-expanding cutting tooth is installed at one end of the outer side of the inner slider. A second spring is installed within the unblocking chamber and connected to the outer sliding sleeve. One end of the oblique injection channel is connected to the hydraulic chamber, and the other end extends through the slope. A crushing cutting tooth is installed on the slope. When the pressure inside the release housing is less than the first preset pressure value, the piston seals the end of the oblique injection channel connected to the hydraulic chamber, and the rotation radius of the reaming cutting teeth is less than the rotation radius of the directional drill bit; when the pressure inside the release housing is greater than the second preset pressure value, the piston opens the end of the oblique injection channel connected to the hydraulic chamber, and the rotation radius of the reaming cutting teeth is greater than the rotation radius of the directional drill bit; the second preset pressure value is greater than the first preset pressure value.

[0007] Preferably, a wedge block that can extend into the hollow channel is installed at one end of the piston near the center of the stepped portion; when the pressure inside the release housing is less than a first preset pressure value, the inclined portion of the wedge block is located inside the hollow channel; when the pressure inside the release housing is greater than a second preset pressure value, the wedge block is completely contained within the hydraulic chamber.

[0008] Preferably, the one-way resistance valve includes a valve body, a valve core, and a third spring. The inner cavity of the valve body includes a narrowed cavity with a frustum-shaped structure. The valve body has an inlet and an outlet communicating with the narrowed cavity. The inlet is close to the end with the smallest diameter of the narrowed cavity, and the outlet is connected to a hydraulic channel. The valve core is adapted to the narrowed cavity. Several notches are opened on the outer wall of the valve core. The cross-sectional area of ​​the notch near the outlet is larger than the cross-sectional area of ​​the notch away from the outlet. The third spring is installed in the inner cavity of the valve body, and the end of the valve core away from the outlet is connected to the third spring.

[0009] Preferably, the one-way resistance valve further includes a telescopic guide rod, the fixed end of which is fixedly connected to the valve body, and the telescopic end of which is connected to the valve core.

[0010] Preferably, a one-way valve mechanism is installed in the inclined firing channel. The one-way valve mechanism includes a fixed plate, a fourth spring, and a one-way valve ball. The fixed plate is fixedly installed in the inclined firing channel. A flared opening is provided at one end of the inclined firing channel that passes through the slope. A one-way valve ball is installed in the flared opening. One end of the fourth spring is connected to the fixed plate and the other end is connected to the one-way valve ball.

[0011] Preferably, a limiting plate is fixedly installed on the flared opening, and the limiting plate is used to contact and cooperate with the one-way valve ball to restrict the one-way valve ball from moving out of the flared opening.

[0012] Preferably, the two ends of the card release housing are respectively provided with a male connector and a female connector.

[0013] Preferably, the unlocking chamber includes an inlet chamber and a movable chamber. The inlet chamber is located on the side of the movable chamber near the center of the unlocking housing. The inlet chamber is connected to the hydraulic channel. The size of the outer sliding sleeve is larger than the size of the inlet chamber, and the outer sliding sleeve moves within the movable chamber.

[0014] Preferably, the outer sliding sleeve includes a first protrusion portion, which is located on the side of the outer sliding sleeve near the center of the release housing, and the second spring is connected to the first protrusion portion.

[0015] Preferably, the inner slider includes a second protrusion located on the side of the inner slider closer to the center of the release housing. The second protrusion is slidably and sealingly connected to the inner wall of the outer sliding sleeve. The outer sliding sleeve includes a limiting ring located on its inner side. The limiting ring is located on the side of the outer sliding sleeve away from the center of the release housing. The limiting ring is used to contact and cooperate with the second protrusion to restrict the second protrusion from disengaging from the outer sliding sleeve.

[0016] Compared with existing technologies, this technical solution has at least one of the following beneficial effects: By setting up an unblocking device, the high-pressure flushing fluid is used to extend the reaming cutting teeth. The reaming cutting teeth can expand the borehole to form an reaming section. The spiral groove structures on both sides transport the coal and rock blocks that are stuck to the drill bit to the step section, and at the same time, they crush the coal and rock blocks. The harder coal and rock blocks that cannot be fully crushed are transported to the step section, where the crushing cutting teeth further crush the coal and rock blocks. The high-pressure water sprayed from the inclined channel can also impact and water cut the coal and rock blocks. The uncrushed coal and rock blocks eventually enter the reaming section, so that the directional drill bit can avoid the uncrushed harder coal and rock blocks when the drill bit is lifted later, thereby realizing the unblocking of the directional drill bit. By setting a one-way resistance valve, the backflow of hydraulic oil from the release chamber to the hydraulic chamber can be restricted, so that the hydraulic oil in the release chamber maintains a large pressure, which can stably support the inner slider and the outer sliding sleeve. This allows the reaming cutting teeth to maintain a large radius of rotation and maintain a large thrust in continuous contact with the inner wall of the borehole, which is convenient for reaming the borehole. At the same time, the water pressure of the high-pressure flushing fluid does not have to be constantly greater than the second preset pressure value, thus saving energy. Attached Figure Description

[0017] Figure 1 The working state of the drill bit according to an embodiment of the present invention Figure 1 (High-pressure cleaning water not connected); Figure 2 The working state of the drill bit according to an embodiment of the present invention Figure 2 (The pressure inside the release housing is less than the first preset pressure value); Figure 3The working state of the drill bit according to an embodiment of the present invention Figure 2 (The pressure inside the release housing is greater than the second preset pressure value); Figure 4 for Figure 1 A schematic diagram of the card decryption device; Figure 5 for Figure 2 A schematic diagram of the card decryption device; Figure 6 for Figure 3 A schematic diagram of the card decryption device; Figure 7 for Figure 4 Sectional view along line AA; Figure 8 for Figure 7 A partially enlarged view of the one-way valve mechanism; Figure 9 for Figure 7 A schematic diagram of a one-way resistance valve (valve core closed). Figure 10 This is another state diagram of a one-way resistance valve (valve core open state). Figure 11 This is a front view of the card unlocking device; In the diagram, 1. Directional drill bit; 2. Single-bend screw motor; 3. Measurement while drilling probe; 4. Directional drill pipe; 5. Unsticking device; 51. Unsticking housing; 511. Hollow channel; 512. Stepped section; 5121. Slope; 513. Circular tube section; 514. Spiral groove structure; 515. Male connector; 516. Female connector; 52. Unsticking mechanism; 521. Hydraulic chamber; 5211. Piston; 5212. First spring; 5213. Wedge block; 522. Unsticking cavity; 5221. Outer sliding sleeve; 52211. First boss section; 52212. Limiting ring section; 5222. Inner slider; 52221. Second boss section 5223, Second Spring; 5224, Inlet Chamber; 5225, Movable Chamber; 523, Hydraulic Channel; 524, Inclined Injection Channel; 525, One-Way Resistance Valve; 5251, Valve Housing; 52511, Narrowing Chamber; 52512, Inlet; 52513, Outlet; 5252, Valve Core; 5253, Third Spring; 5254, Notch; 5255, Telescopic Guide Rod; 526, Hole Enlarging Cutting Teeth; 527, Crushing Cutting Teeth; 528, One-Way Valve Mechanism; 5281, Fixed Plate; 5282, Fourth Spring; 5283, One-Way Valve Ball; 5284, Trumpet Mouth; 5285, Limiting Plate; 6, Hole Enlarging Section. Detailed Implementation

[0018] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0019] Please see Figures 1 to 11 This application provides a directional drilling tool for fractured formations, comprising a directional drill bit 1, a single-bend screw motor 2, a measurement-while-drilling (MWD) probe 3, an unsticking device 5, and a directional drill rod 4 connected in sequence. The directional drill bit 1, single-bend screw motor 2, MWD probe 3, and directional drill rod 4 are all existing technologies and all have a hollow structure. High-pressure flushing fluid enters sequentially through the directional drill rod 4, unsticking device 5, MWD probe 3, single-bend screw motor 2, and directional drill bit 1, and is finally ejected from the directional drill bit 1. The single-bend screw motor 2 converts the kinetic energy of the high-pressure flushing fluid into mechanical energy to drive the directional drill bit 1 to rotate. The directional drill bit 1 rotates while ejecting fluid, facilitating directional drilling. The MWD probe 3 can measure the spatial parameters of the borehole trajectory and the tool face direction of the single-bend screw motor 2, thereby determining the directional drilling direction based on the deviation between the actual borehole trajectory and the designed trajectory. The rotational power of the drilling rig is transmitted sequentially through the directional drill rod 4, the unsticking device 5, and the measurement-while-drilling probe 3 to the single-bend screw motor 2 and the directional drill bit 1, so that when high-pressure flushing fluid is not supplied, the directional drill bit 1 can be rotated and adjusted to the directional drilling direction.

[0020] The above are all existing technologies. The key point of this embodiment is that it is equipped with a card-unblocking device 5. The card-unblocking device 5 includes a card-unblocking shell 51 with a hollow channel 511 and a plurality of card-unblocking mechanisms 52 distributed circumferentially on the card-unblocking shell 51. The card-unblocking shell 51 includes a stepped portion 512 located in the middle and circular tube portions 513 located on both sides of the stepped portion 512. The wall thickness of the stepped portion 512 is greater than the wall thickness of the circular tube portion 513. The two sides of the stepped portion 512 are slopes 5121. The circular tube portion 513 is provided with a spiral groove structure 514. The spiral groove structures 514 on the two circular tube portions 513 have opposite rotation directions. In this embodiment, the spiral groove structure 514 is a spiral blade fixedly installed on the circular tube portion 513. The outer diameter of the spiral blade is smaller than the outer diameter of the stepped portion 512. Other embodiments may also provide a spiral groove structure 514 opened on the circular tube portion 513, but the spiral groove of this structure is shallow, and the effect of crushing, conveying and breaking hard coal and rock blocks is poor. The card release mechanism 52 includes a hydraulic chamber 521, a card release chamber 522, a hydraulic channel 523, and an oblique injection channel 524 disposed within the stepped portion 512. The hydraulic chamber 521 communicates with the hollow channel 511. A piston 5211 is slidably and sealed within the hydraulic chamber 521. Hydraulic oil is injected into the hydraulic chamber 521, and the piston 5211 restricts the flow of hydraulic oil into the hollow channel 511. A limiting protrusion is provided at the bottom of the hydraulic chamber 521 to prevent the piston 5211 from disengaging from the hydraulic chamber 521 and entering the hollow channel 511. A first spring 5212 is installed within the hydraulic chamber 521 and is connected to the piston 5211. A one-way resistance valve 525 is installed on the side away from the center of the step 512. The one-way resistance valve 525 is connected to the release chamber 522 through the hydraulic channel 523. An outer sliding sleeve 5221 is installed in the release chamber 522. An inner slider 5222 is installed in the outer sliding sleeve 5221. A hole-expanding cutting tooth 526 is installed on one end of the outer side of the inner slider 5222. A second spring 5223 is installed in the release chamber 522 and is connected to the outer sliding sleeve 5221. One end of the inclined injection channel 524 is connected to the hydraulic chamber 521 and the other end passes through the slope 5121. A crushing cutting tooth 527 is installed on the slope 5121. When the pressure inside the release housing 51 is less than the first preset pressure value, the piston 5211 seals the end of the oblique injection channel 524 connected to the hydraulic chamber 521, and the rotation radius of the reaming cutting teeth 526 is less than the rotation radius of the directional drill bit 1; when the pressure inside the release housing 51 is greater than the second preset pressure value, the piston 5211 opens the end of the oblique injection channel 524 connected to the hydraulic chamber 521, and the rotation radius of the reaming cutting teeth 526 is greater than the rotation radius of the directional drill bit 1; the second preset pressure value is greater than the first preset pressure value.

[0021] In this embodiment, when high-pressure flushing fluid is not introduced during directional drilling, please refer to [link to relevant documentation]. Figure 1 and Figure 4 The single-bend screw motor 2 will not drive the directional drill bit 1 to rotate; when introducing high-pressure flushing fluid, please refer to [the relevant instructions]. Figure 2 and Figure 5When the high-pressure flushing fluid passes through the hollow channel 511, it pushes the piston 5211 deeper into the hydraulic chamber 521, causing the first spring 5212 to compress. The piston 5211 then pushes some of the hydraulic oil in the hydraulic chamber 521 into the unblocking chamber 522 through the one-way resistance valve 525 and the hydraulic channel 523. The hydraulic oil entering the unblocking chamber 522 first pushes the inner slider 5222 to move, causing part of the inner slider 5222 to extend out of the outer sliding sleeve 5221. The water pressure of the high-pressure flushing fluid is controlled to be less than the first preset pressure value. The thrust of the water pressure on the piston 5211 is less than the limit compression of the first spring 5212. In this way, the displacement of the piston 5211 will not be too large, and the displacement of the reaming cutting teeth 526 will not be too large. The rotation radius of the reaming cutting teeth 526 is less than the rotation radius of the directional drill bit 1. The reaming cutting teeth 526 will move inside the drill hole and will not ream the drill hole. like Figure 3 As shown, when the drill bit gets stuck after drilling is completed and the drill is lifted, the unsticking device 5 is used to unstick the directional drill bit 1. Specifically, the water pressure of the high-pressure flushing fluid is controlled to be greater than the second preset pressure value, the first spring 5212 is further compressed, the piston 5211 further increases its displacement, and more hydraulic oil in the hydraulic chamber 521 is injected into the unsticking chamber 522, pushing the outer sliding sleeve 5221 and the inner slider 5222 to extend outward. The second spring 5223 is compressed, the piston 5211 no longer closes the oblique injection channel 524, and the oblique injection channel 524 opens. At this time, the rotation radius of the reaming cutting teeth 526 is greater than the rotation radius of the directional drill bit 1; the reaming cutting teeth 526 can ream the hole; then drilling continues, allowing the unsticking device to unstick. The device 5 moves towards the directional drill bit 1 to crush and transfer the coal and rock blocks between the unjamming device 5 and the directional drill bit 1; the reaming cutting teeth 526 advance while reaming the borehole to form the reaming section 6; the spiral groove structures 514 on both sides transport the coal and rock blocks that caused the drill jam to the step section 512, and at the same time crush the coal and rock blocks. The harder coal and rock blocks that cannot be fully crushed are transported to the step section 512, where the crushing cutting teeth 527 further crush the coal and rock blocks. The high-pressure water sprayed from the inclined channel 524 can also impact and cut the coal and rock blocks. The uncrushed coal and rock blocks eventually enter the reaming section 6, so that the directional drill bit 1 can avoid the uncrushed harder coal and rock blocks when the drill is lifted later, thereby realizing the unjamming of the directional drill bit 1; The water pressure of the high-pressure flushing fluid does not need to be greater than the second preset pressure value all the time. Because a one-way resistance valve 525 is provided, the hydraulic oil in the release chamber 522 can be restricted from flowing back to the hydraulic chamber 521, so that the hydraulic oil in the release chamber 522 can maintain a large pressure, which can stably support the inner slider 5222 and the outer sliding sleeve 5221, so that the hole-reaming cutting teeth 526 can maintain a large rotation radius and maintain a large thrust in continuous contact with the inner wall of the borehole, which is convenient for hole reaming. After the blockage between the unblocking device 5 and the directional drill bit 1 is cleared, before starting to lift the drill, wait for a period of time while stopping the flow of high-pressure flushing fluid, so that the hydraulic oil in the unlocking chamber can slowly flow back to the hydraulic chamber 521 through the one-way resistance valve 525, so that the outer sliding sleeve 5221 and the inner slider 5222 are reset to the unlocking chamber, and then the drill is lifted to avoid the inner slider 5222 extending too much and causing the drill to get stuck. If there is a large area of ​​stuck drill bit in the direction away from the directional drill bit 1, the same principle as above applies during the drill lifting process. The unsticking device 5 slowly lifts the drill bit while expanding the hole, and the spiral groove structure 514 on the side close to the directional drill rod 4 pushes the coal and rock blocks to the expanded hole section 6 to achieve unsticking.

[0022] In one specific embodiment, to facilitate sealing the end of the inclined injection channel 524 connected to the hydraulic chamber 521 at the first preset pressure value, and with the rotation radius of the reaming cutting teeth 526 being smaller than the rotation radius of the directional drill bit 1, when the pressure inside the release housing 51 is greater than the second preset pressure value, the piston 5211 can open the end of the inclined injection channel 524 connected to the hydraulic chamber 521, and with the rotation radius of the reaming cutting teeth 526 being larger than the rotation radius of the directional drill bit 1, a wedge block 5213 extending to the hollow channel 511 is installed at the end of the piston 5211 near the center of the step portion 512. The wedge block 5213 has an inclined surface on its end face facing the hollow channel 511. When the high-pressure cleaning fluid passes through the hollow channel 511, it interacts with the inclined surface. When the inclined surface of the wedge 5213 contacts, it pushes the inclined wedge 5213 to move. When the pressure inside the release housing 51 is less than the first preset pressure value, the water pressure of the high-pressure cleaning fluid is insufficient to completely push the inclined wedge 5213 into the hydraulic chamber 521, so that the inclined part of the inclined wedge 5213 is located in the hollow channel 511. When the pressure inside the release housing 51 is greater than the second preset pressure value, the water pressure of the high-pressure cleaning fluid is sufficient to completely push the inclined wedge 5213 into the hydraulic chamber 521. At this time, the inclined wedge 5213 is completely contained in the hydraulic chamber 521, and the piston 5211 can move to the end away from the inclined injection channel 524 and the hydraulic chamber 521, so that the water inlet end of the inclined injection channel 524 is opened, and the inclined injection channel 524 can spray out high-pressure cleaning fluid.

[0023] In one specific embodiment, to limit the hydraulic oil flowing back from the release chamber 522 to the hydraulic chamber 521, so that the hydraulic oil in the release chamber 522 can maintain a higher pressure, please refer to [link to relevant documentation]. Figure 9 and Figure 10The one-way resistance valve 525 includes a valve housing 5251, a valve core 5252, and a third spring 5253. The inner cavity of the valve housing 5251 includes a narrowed cavity 52511 with a frustum-shaped structure. The valve housing 5251 has an inlet 52512 and an outlet 52513 communicating with the narrowed cavity 52511. The valve housing 5251 is cylindrical. The inlet 52512 is located at one axial end of the valve housing 5251 and is connected to the hydraulic cavity 521. The outlet 52513 is radially opened at the end of the valve housing 5251 away from the inlet 52512. The inlet 52512 is close to the end of the narrowed cavity 52511 with the smallest diameter. 52513 is connected to the hydraulic channel 523 for conduction. The valve core 5252 is adapted to the narrowing cavity 52511. The valve core 5252 has a frustum structure. Several notches 5254 are opened on the outer wall of the valve core 5252. When the valve core 5252 abuts against the inner wall of the narrowing cavity 52511, the notches 5254 form a channel for hydraulic oil to flow. The cross-sectional area of ​​the notch 5254 near the outlet 52513 is larger than the cross-sectional area of ​​the end away from the outlet 52513. The third spring 5253 is installed in the inner cavity of the valve body 5251. The end of the valve core 5252 away from the outlet 52513 is connected to the third spring 5253.

[0024] In this embodiment, when hydraulic oil flows from hydraulic chamber 521 into unblocking chamber 522, the hydraulic oil pushes the third spring 5253 to compress, causing valve core 5252 to move towards the end with the largest diameter of narrowing chamber 52511. Valve core 5252 no longer abuts against the inner wall of narrowing chamber 52511, increasing the total cross-sectional area for hydraulic oil flow between valve core 5252 and narrowing chamber 52511, allowing hydraulic oil in hydraulic chamber 521 to flow quickly into unblocking chamber 522. Conversely, when hydraulic oil in unblocking chamber 522 flows back into hydraulic chamber 521, both hydraulic oil and the third spring push valve core 5252, causing valve core 5252 to close. Hydraulic oil can only enter notch 5254 from the end with the smaller cross-sectional area, and then enter inlet 52512 and hydraulic chamber 521 from the end with the larger cross-sectional area, thereby reducing the total cross-sectional area for hydraulic oil flow and achieving unidirectional flow restriction of hydraulic oil.

[0025] In one specific embodiment, to ensure smooth linear movement of the valve core 5252, the one-way resistance valve 525 further includes a telescopic guide rod 5255. The fixed end of the telescopic guide rod 5255 is fixedly connected to the valve housing 5251, and the telescopic end of the telescopic guide rod 5255 is connected to the valve core 5252. The telescopic guide rod 5255 is a prior art telescopic rod, comprising a rod and a sleeve. The rod can move linearly within the sleeve, thereby achieving telescopic movement.

[0026] In one specific embodiment, to prevent impurities such as drilling mud from entering the inclined injection channel 524, a one-way valve mechanism 528 is installed inside the inclined injection channel 524. Please refer to [link to relevant documentation]. Figure 8The one-way valve mechanism 528 includes a fixed plate 5281, a fourth spring 5282, and a one-way valve ball 5283. The fixed plate 5281 is fixedly installed in the inclined injection channel 524. The inclined injection channel 524 has a flared mouth 5284 at one end of the slope 5121. The one-way valve ball 5283 is installed in the flared mouth 5284. One end of the fourth spring 5282 is connected to the fixed plate 5281 and the other end is connected to the one-way valve ball 5283. The fourth spring 5282 provides tension to the one-way valve ball 5283, causing the one-way valve ball 5283 to be stuck at the narrow end of the flared mouth 5284, thus sealing the flared mouth 5284. In this way, mud and other impurities in the borehole cannot enter the oblique injection channel 524. When the high-pressure flushing fluid in the hollow channel 511 is introduced into the oblique injection channel 524, the high-pressure flushing fluid will push the one-way valve ball 5283, causing the flared mouth 5284 to open, thereby causing the high-pressure flushing fluid to spray out of the oblique injection channel 524.

[0027] In one specific embodiment, to prevent the one-way valve ball 5283 from moving out of the horn opening 5284, a limiting plate 5285 is fixedly installed on the horn opening 5284. When high-pressure flushing fluid is introduced into the hollow channel 511 in the oblique injection channel 524, the high-pressure flushing fluid will push the one-way valve ball 5283 to move outward of the horn opening 5284, so that the horn opening 5284 opens, and the limiting plate 5285 contacts the one-way valve ball 5283, thereby restricting the one-way valve ball 5283 from moving out of the horn opening 5284.

[0028] In one specific embodiment, to facilitate the installation of the unblocking device 5, a male connector 515 and a female connector 516 are respectively provided at both ends of the unblocking housing 51. The directional drill pipe 4 and the measurement while drilling probe 3 are provided with connectors adapted to the male connector 515 and the female connector 516. By providing the male connector 515 and the female connector 516, the unblocking device 5 can be easily connected to the directional drill pipe 4 and the measurement while drilling probe 3.

[0029] In one specific embodiment, to facilitate the delivery of hydraulic oil from the hydraulic channel 523 to the unlocking cavity 522, the unlocking cavity 522 includes an inlet cavity 5224 and a movable cavity 5225. The inlet cavity 5224 is located on the side of the movable cavity 5225 near the center of the unlocking housing 51. The inlet cavity 5224 is connected to the hydraulic channel 523. The outer sliding sleeve 5221 is larger than the size of the inlet cavity 5224. The outer sliding sleeve 5221 moves within the movable cavity 5225. In this way, the outer sliding sleeve 5221 will not move within the inlet cavity 5224 and will not block the hydraulic channel 523. This allows the hydraulic channel 523 to easily deliver hydraulic oil to the unlocking cavity 522, enabling the hydraulic oil to smoothly push the outer sliding sleeve 5221 and the inner slider 5222 to move.

[0030] In one specific embodiment, to facilitate the installation of the second spring 5223 and simultaneously restrict the outer sliding sleeve 5221 from moving out of the unlocking cavity 522, the outer sliding sleeve 5221 includes a first protrusion 52211, which is located on the side of the outer sliding sleeve 5221 near the center of the unlocking housing 51. The second spring 5223 is connected to the first protrusion 52211. The inner side of the end of the unlocking cavity 522 away from the center of the unlocking housing 51 has a limiting structure that can abut against the first protrusion 52211 to restrict the outer sliding sleeve 5221 from moving out of the unlocking cavity 522.

[0031] In one specific embodiment, to restrict the inner slider 5222 from sliding out of the outer sliding sleeve, the inner slider 5222 includes a second protrusion 52221. The second protrusion 52221 is located on the side of the inner slider 5222 near the center of the release housing 51. The second protrusion 52221 is slidably and sealingly connected to the inner wall of the outer sliding sleeve 5221. The outer sliding sleeve 5221 includes a limiting ring 52212 located on its inner side. The limiting ring 52212 is located on the side of the outer sliding sleeve 5221 away from the center of the release housing 51. The limiting ring 52212 is used to contact and cooperate with the second protrusion 52221 to restrict the second protrusion 52221 from disengaging from the outer sliding sleeve 5221.

[0032] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0033] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

Claims

1. A directional drilling tool for fractured formations, comprising a directional drill bit, a single-bend screw motor, a measurement-while-drilling (MWD) probe, and a directional drill rod, characterized in that, It also includes a release device, wherein the directional drill bit, single-bend screw motor, drilling measurement probe, release device and directional drill rod are connected in sequence; The card-unlocking device includes a card-unlocking housing with a hollow channel and multiple card-unlocking mechanisms distributed circumferentially on the card-unlocking housing. The card-unlocking housing includes a stepped section in the middle and circular tube sections on both sides of the stepped section. The two sides of the stepped section are sloped, and the circular tube sections are provided with a spiral groove structure. The unblocking mechanism includes a hydraulic chamber, an unblocking chamber, a hydraulic channel, and an oblique injection channel disposed within the stepped portion. The hydraulic chamber is connected to the hollow channel. A piston is slidably sealed and installed within the hydraulic chamber. A first spring is installed within the hydraulic chamber and connected to the piston. A one-way resistance valve is installed on the side of the hydraulic chamber away from the center of the stepped portion, and the one-way resistance valve is connected to the unblocking chamber through the hydraulic channel. An outer sliding sleeve is slidably sealed and installed within the unblocking chamber. An inner slider is slidably sealed and installed within the outer sliding sleeve. A hole-expanding cutting tooth is installed at one end of the outer side of the inner slider. A second spring is installed within the unblocking chamber and connected to the outer sliding sleeve. One end of the oblique injection channel is connected to the hydraulic chamber, and the other end extends through the slope. A crushing cutting tooth is installed on the slope. The one-way resistance valve includes a valve body, a valve core, and a third spring. The inner cavity of the valve body includes a narrowed cavity with a frustum-shaped structure. The valve body has an inlet and an outlet that communicate with the narrowed cavity. The inlet is close to the end with the smallest diameter of the narrowed cavity, and the outlet is connected to the hydraulic channel. The valve core is adapted to the narrowed cavity. Several notches are opened on the outer wall of the valve core. The cross-sectional area of ​​the notch near the outlet is larger than the cross-sectional area of ​​the notch away from the outlet. The third spring is installed in the inner cavity of the valve body, and the end of the valve core away from the outlet is connected to the third spring. When the pressure inside the release housing is less than the first preset pressure value, the piston seals the end of the oblique injection channel connected to the hydraulic chamber, and the rotation radius of the reaming cutting teeth is less than the rotation radius of the directional drill bit; when the pressure inside the release housing is greater than the second preset pressure value, the piston opens the end of the oblique injection channel connected to the hydraulic chamber, and the rotation radius of the reaming cutting teeth is greater than the rotation radius of the directional drill bit; the second preset pressure value is greater than the first preset pressure value. A one-way valve mechanism is installed in the inclined firing channel. The one-way valve mechanism includes a fixed plate, a fourth spring, and a one-way valve ball. The fixed plate is fixedly installed in the inclined firing channel. A flared opening is provided at one end of the inclined firing channel that passes through the slope. A one-way valve ball is installed in the flared opening. One end of the fourth spring is connected to the fixed plate and the other end is connected to the one-way valve ball.

2. The directional drilling tool for fractured formations according to claim 1, characterized in that, The piston is equipped with a wedge block that extends into the hollow channel at one end near the center of the stepped portion; when the pressure inside the release housing is less than the first preset pressure value, the inclined portion of the wedge block is located inside the hollow channel; when the pressure inside the release housing is greater than the second preset pressure value, the wedge block is completely contained within the hydraulic chamber.

3. The directional drilling tool for fractured strata according to claim 1, characterized in that, The one-way resistance valve also includes a telescopic guide rod, the fixed end of which is fixedly connected to the valve body, and the telescopic end of which is connected to the valve core.

4. The directional drilling tool for fractured formations according to claim 1, characterized in that, A limiting plate is fixedly installed on the flared opening. The limiting plate is used to contact and cooperate with the one-way valve ball to restrict the one-way valve ball from moving out of the flared opening.

5. The directional drilling tool for fractured strata according to claim 1, characterized in that, The release housing has a male connector and a female connector at each end.

6. The directional drilling tool for fractured formations according to claim 1, characterized in that, The unlocking chamber includes an inlet chamber and a movable chamber. The inlet chamber is located on the side of the movable chamber near the center of the unlocking housing. The inlet chamber is connected to the hydraulic channel. The size of the outer sliding sleeve is larger than the size of the inlet chamber. The outer sliding sleeve moves within the movable chamber.

7. The directional drilling tool for fractured strata according to claim 1, characterized in that, The outer sliding sleeve includes a first protrusion, which is located on the side of the outer sliding sleeve near the center of the release housing, and a second spring is connected to the first protrusion.

8. The directional drilling tool for fractured formations according to claim 1, characterized in that, The inner slider includes a second protrusion located on the side of the inner slider closer to the center of the release housing. The second protrusion is slidably and sealingly connected to the inner wall of the outer sliding sleeve. The outer sliding sleeve includes a limiting ring located on its inner side. The limiting ring is located on the side of the outer sliding sleeve away from the center of the release housing. The limiting ring is used to contact and cooperate with the second protrusion to restrict the second protrusion from disengaging from the outer sliding sleeve.

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