Push-type guide drill bit, drilling tool and drilling method for underground coal mine

Abstract

The present invention relates to a push-type guide drill bit, a drilling tool and a drilling method for underground coal mines. The present invention introduces flushing fluid into a groove body arranged on the outer surface of the drill bit body, and uses the flushing fluid to drive a push leg arranged in the groove body to extend out of the groove body to adjust the drilling direction. Therefore, the present invention has higher drilling efficiency, higher trajectory control accuracy and higher safety.

Description

Technical Field

[0001] The invention relates to a drill bit, a drilling tool and a drilling method, and belongs to the field of underground tunnel drilling in coal mines, and in particular to an underground push-type guide drill bit, a drilling tool and a drilling method in coal mines. Background Art

[0002] Near-horizontal directional drilling in underground coal mines has the advantages of deep and long holes, controllable trajectories, multiple uses of one hole, and centralized and advance disaster prevention and control. It can achieve advance, regional, and precise disaster prevention and control, and is widely used in the field of coal mine safety in my country.

[0003] Directional drilling tools are the core and key to directional drilling construction. At present, directional drilling technology equipment based on screw drilling tools has been developed at home and abroad. Through sliding inclination and composite stable inclination trajectory control, long-distance near-horizontal directional drilling in coal mines has been achieved. However, the existing technical equipment still has the disadvantages of low drilling efficiency, low drilling trajectory control accuracy, high safety risk of directional drilling tools, and difficulty in deep hole construction, which are specifically reflected as follows:

[0004] (1) Low drilling efficiency. At present, directional drilling mainly relies on the power output of the screw drill at the bottom of the hole to perform local rotation and rock crushing at the bottom of the hole. The screw drill mainly converts the kinetic energy of the drilling flushing medium into mechanical energy for rock crushing. Its rated output torque is much smaller than the rated output torque of the hole drilling rig. The drilling power is small and the drilling efficiency is low, especially the rock formation drilling speed is extremely slow.

[0005] (2) Low drilling trajectory control accuracy. Drilling trajectory measurement is the basis of drilling trajectory control. Affected by the structural characteristics of the screw drill, its length is generally 3 to 5 meters. The drilling trajectory measurement probe is installed between the screw drill and the directional drill rod, and the distance from the drill bit is generally 6 to 8 meters. The measurement data lags behind the actual situation at the bottom of the hole, and the trajectory parameters at the drill bit need to be estimated, which affects the drilling trajectory measurement and control accuracy. At the same time, when the screw drill is used for directional drilling, the drilling trajectory is controlled by adjusting the direction of the structural bend angle set on it. However, the directional drill is affected by the reaction force of the drill bit's rock crushing, which will produce a reverse torsion angle, resulting in inaccurate control of the screw drill structure bend direction, which reduces the drilling trajectory control accuracy.

[0006] (3) Directional drilling tools have high safety risks. When using a screw drill for sliding directional correction, the direction of the screw drill must be kept unchanged. At this time, the directional drill cannot rotate and can only rely on the drilling flushing medium to remove slag. The drilling slag removal efficiency is reduced, and drill jams are easily caused by the accumulation of drilling slag. When using a screw drill for rotary stabilization drilling, the directional drill needs to rotate, but due to the influence of the screw motor structure bend angle, the rotation force of the directional drill is complex, and it is easy to cause drilling tool fatigue damage, fracture and other in-hole accidents.

[0007] (4) Deep hole drilling is difficult. When the screw drill is used for sliding directional correction, the directional drill slides and feeds, and the frictional resistance acting on the drill rod is much greater than the rotational frictional resistance. The drill drag phenomenon is serious, and the drilling power is difficult to transmit to the bottom of the hole. The drilling power at the bottom of the hole is insufficient, which restricts the drilling depth.

[0008] Therefore, the present invention aims at the needs of accurate, efficient and safe construction of directional long drilling holes in coal mines, and at the shortcomings of current directional drilling technology and equipment in coal mines, and studies and designs a rotary push-type near-drill bit measurement guide drill tool and drilling method for coal mines, which overcomes the above-mentioned defects. Summary of the invention

[0009] The purpose of the present invention is to provide a push-type guide drill bit, drilling tool and drilling method for underground coal mines in view of the shortcomings of current underground coal mine directional drilling technology and equipment, such as low drilling efficiency, low drilling trajectory control accuracy, high safety risk of directional drilling tools, and difficulty in deep hole construction.

[0010] The technical solution adopted by the present invention is:

[0011] The utility model discloses an underground rotary push-type near-drill-bit measuring guide drilling tool in a coal mine, which is composed of a double-wall drill rod, a double-wall connector, a near-drill-bit measuring probe and a push-type directional drill bit connected in sequence.

[0012] The double-wall drill pipe includes an outer drill pipe, and also includes a double female joint, a thrust bearing A, a thrust bearing B, a locking nut A and an inner drill pipe positioned in the outer drill pipe. The outer drill pipe is connected by a threaded method, and a female thread is arranged at the front end and a male thread is arranged at the rear end. Steps are arranged at the inner wall near the female thread and the root of the male thread; the outer diameter of the double female joint is larger than that of the inner drill pipe, and a hexagonal female joint is arranged at the front end and a female thread is arranged at the rear end; the front end of the inner drill pipe is provided with a male thread, the rear end is provided with a hexagonal male joint, and the root of the hexagonal male joint is provided with a male thread; the thrust bearing A is installed at the step at the root of the female thread of the outer drill pipe; the thrust bearing B is installed at the step at the root of the male thread of the outer drill pipe; the locking nut A is installed at the male thread at the root of the hexagonal male joint of the inner drill pipe; the inner drill pipe is radially positioned in the outer drill pipe by the thrust bearing A and the thrust bearing B, and is axially limited by the locking nut A, and can rotate circumferentially relative to the outer drill pipe, but cannot move axially.

[0013] The double-wall connector comprises an upper connector and a lower connector connected in sequence, both ends of the upper connector are female threads, the front end is connected to the male thread of the external drill rod, the rear end is connected to the lower connector, and a step is provided inside; both ends of the lower connector are provided with male threads, the front end is connected to the upper connector, the rear end is connected to the push-type directional drill bit, and a step is provided inside; the thrust bearing group is installed between the upper connector and the lower connector, and is limited by two steps; a connector core tube is also provided inside the double-wall connector, the front end of the connector core tube is provided with a hexagonal female connector, the outer surface of the root of the hexagonal female connector is provided with a male thread, the rear end of the connector core tube is provided with a hexagonal male connector, and the root of the male connector is provided with a secondary step, the connector core tube passes through the thrust bearing group, the rear end is limited by the first step at the root of the male connector, and the front end is limited by a locking female B connected to the male thread at the root of the hexagonal female connector, and can rotate circumferentially relative to the upper connector and the lower connector, but cannot move axially.

[0014] The near-drill-bit measuring probe is installed in the connector core tube of the double-wall connector, and can measure parameters such as drilling trajectory parameters, formation parameters, and the deflection direction of a push-type directional drill bit. The measurement data can be sent to the hole mouth by transmission methods such as wired, mud pulse or electromagnetic wave. The length of the near-drill-bit measuring probe can be changed according to different measurement parameters and transmission methods; the drilling trajectory parameters include inclination and azimuth; the formation parameters include but are not limited to azimuthal resistivity and azimuthal gamma.

[0015] The push-to-pull directional drill bit comprises a drill body, the outer part of the drill body is a circular structure, the front end is provided with a female thread connected with a double-wall connector, three rectangular grooves are evenly arranged in the radial direction in the middle of the outer surface, and a cover is connected around the rectangular groove by fastening screws, a push-to-pull palm is installed in the rectangular groove, a push-to-pull palm reset spring is arranged between the push-to-pull palm and the cover, the push-to-pull palm can extend out of the cover or retract into the rectangular groove, and a sealing ring B is arranged between the rectangular groove and the push-to-pull palm; two step holes are arranged inside the drill body, wherein the first step hole is a circular structure, and a retaining ring groove is processed near the front end of the first step hole; the second step hole is a circular structure, and three guide flow channels connected with the rectangular groove are evenly arranged in the radial direction near the front end of the second step hole; a directional flow distribution valve is arranged in the first step, the front end of the directional flow distribution valve is limited by a retaining ring installed in the retaining ring groove of the first step hole, and the rear end extends into the second step hole and is limited by the directional flow distribution valve reset spring installed in the second step hole; four drill blades are processed at the rear end of the drill body.

[0016] When the double-wall drill rods are connected, the outer drill rods are connected by threads, which can transmit both rotational power and forward power; the double female joint hexagonal female joint and the inner drill rod hexagonal male joint are plugged into each other and only transmit rotational power.

[0017] The outer drill rod surface shape of the double-wall drill rod can be selected according to the target formation to be drilled. When the target formation to be drilled is a medium-hard coal seam or rock formation, the outer surface is an outer flat circular structure; when the formation to be drilled is a broken soft coal seam, the outer surface is a spiral, triangular or triangular spiral or other special-shaped structures.

[0018] The connector core tube of the double-wall connector is a hollow structure, and an instrument compartment for installing a near-drill-bit measuring probe is arranged inside, and the length of the instrument compartment can be adjusted according to the length of the near-drill-bit measuring probe; a sealing body is arranged at the second step at the root of the male joint of the connector core tube to seal the gap between the connector core tube and the lower joint of the connector; a diversion hole is radially arranged at the corresponding position of the connector core tube and the thrust bearing group, which cooperates with the sealing body to guide the annular gap flushing liquid between the inner drill rod and the outer drill rod of the double-wall drill pipe into the connector core tube.

[0019] The signal transmission modes of the near-drill-bit measuring probe include wired mode, mud pulse mode and electromagnetic wave transmission mode.

[0020] The push-type directional drill bit is evenly provided with three circular inclination stabilizing flow channels parallel to the second step hole and connected to the first step hole in the drill body, and a drill water eye is provided at the rear end; the bottom of the rectangular groove is provided with a pressure relief hole; the inclination stabilizing flow channels and the pressure relief holes are both connected to the drill water eye.

[0021] The front end of the directional flow distribution valve of the push-type directional drill bit is provided with a hexagonal female joint, which is connected to the hexagonal male joint of the connector core tube. The root of the hexagonal female joint is provided with a step, which is limited by a retaining spring. The step is provided with a sealing ring groove, in which a sealing ring A is installed; a flow limiting hole with an axial blind hole is provided at the center of the directional flow distribution valve, and a valve port is provided radially of the flow limiting hole. A spring base is provided at the rear end of the directional flow distribution valve.

[0022] The outer contour of the push-to-pull leg of the push-to-pull directional drill bit is in the shape of an arc and is inlaid with a diameter-protecting alloy.

[0023] The directional flow distribution valve of the push-type directional drill bit can move axially and rotate circumferentially along the drill bit body, but the maximum axial movement distance is less than the length of the hexagonal female joint of the directional flow distribution valve; when the directional flow distribution valve moves downward and the valve port completely enters the second step hole, the valve port is connected to the guide flow channel opposite to it, and is only connected to one guide flow channel; the valve port of the directional flow distribution valve is oriented in the deflection direction of the push-type directional drill bit.

[0024] A method for drilling a rotary push-type near-drill-bit measuring guide drill tool in a coal mine, comprising the following steps:

[0025] Step 1: Drilling tool connection. After completing the construction of the borehole casing section, install the push-to-pull directional drill bit, double-wall connector, near-drill bit measurement probe and double-wall drill pipe in sequence, and use the drilling rig to lower the rotating push-to-pull near-drill bit measurement guide drill bit to 0.5m from the bottom of the hole.

[0026] Step 2: Parameter measurement and directional drilling mode selection. Use the near-drilling probe to measure the drilling trajectory parameters, formation parameters and the push-to-pull directional drill bit deflection direction, and select the directional drilling mode according to the deviation between the actual drilling trajectory and the designed trajectory and the formation conditions.

[0027] Step 3: Directional drilling. Drill holes according to the selected directional drilling mode, and control the actual drilling trajectory to extend along the designed trajectory.

[0028] Step 4: Drilling is completed. Repeat steps 2 and 3 to perform drilling construction until the hole reaches the designed depth, then withdraw the rotary push-type near-drill bit measuring guide drill from the hole to complete the drilling construction.

[0029] The directional drilling modes in step 2 include two types: a deflection correction drilling mode and a deflection stabilization drilling mode.

[0030] The specific basis for selecting the directional drilling mode in step 2 is: when the drilling formation is the target formation and the deviation between the actual drilling trajectory and the designed trajectory is less than the maximum allowable deviation, the steady-inclination drilling mode is adopted; otherwise, the deflection correction drilling mode is adopted.

[0031] During the directional drilling in step 3, the deflection correction drilling mode includes the following sub-steps:

[0032] Step 1: Adjust the directional correction direction. Use the drilling rig to rotate the inner drill rod of the double-wall drill rod, drive the connector core tube of the double-wall connector to rotate, and then drive the directional flow distribution valve of the push-to-pull directional drill bit to rotate until the valve port direction of the directional flow distribution valve is consistent with the designed directional correction direction; lock the inner drill rod to keep the valve port direction of the directional flow distribution valve unchanged.

[0033] Step 2: Directional deflection correction construction. High-pressure flushing fluid is injected into the double-wall drill pipe. Under the push of the high-pressure flushing fluid, the return spring of the directional flow distribution valve is compressed, the directional flow distribution valve moves downward, and the valve port enters the second step hole; the push-to-pull directional drill bit is driven to rotate and break the formation by rotating the drilling rig and pushing the outer drill pipe of the double-wall drill pipe; during the rotation of the push-to-pull directional drill bit, when the direction of the guide flow channel is opposite to the valve port of the directional flow distribution valve, the valve port is connected to the corresponding guide flow channel, and the high-pressure flushing fluid enters the corresponding rectangular groove along the valve port of the directional flow distribution valve and the guide flow channel, pushing the corresponding push-to-pull palm out of the cover, supporting on the hole wall, applying lateral force to the push-to-pull directional drill bit, and the other push-to-pull palms remain retracted, so that the push-to-pull directional drill bit is corrected in the set direction. After the action, the high-pressure flushing fluid flows out along the pressure relief hole and the drill water eye, and after cooling the directional drill bit, it carries the drilling debris generated by drilling and flows out from the gap between the outer drill pipe of the double-wall drill pipe and the wall of the borehole.

[0034] Step 3: Reset the push-pull directional drill bit. After the directional correction is completed, stop injecting high-pressure flushing fluid into the double-wall drill pipe, the directional flow distribution valve is reset under the action of the directional flow distribution valve reset spring, and the push-pull palm is retracted into the rectangular groove under the action of the push-pull palm reset spring.

[0035] During the directional drilling in step three, the specific operation of the steady-inclination drilling mode is as follows: low-pressure flushing fluid is injected into the double-wall drill pipe, and the directional distribution valve is under the action of the directional distribution valve reset spring, the valve port is still located in the first step hole, the low-pressure flushing fluid flows out along the directional distribution valve valve port, the steady-inclination flow channel, and the drill bit water eye, and after cooling the directional drill bit, it carries the drill cuttings generated by drilling and flows out from the gap between the outer drill pipe of the double-wall drill pipe and the borehole wall; the double-wall drill pipe is pushed by the drilling rig to drive the push-type directional drill bit to rotate and crush the formation, at this time, the push-pull palm is kept in a retracted state under the action of the push-pull palm reset spring, no lateral thrust is generated, and the inclination is not corrected in a fixed direction, and steady-inclination drilling is performed along the current borehole inclination and azimuth.

[0036] The present invention has developed a rotary push-type near-drill-bit measurement and guidance drilling tool for underground coal mines, and developed a rotary guidance drilling method based on the drilling tool. The drilling tool can be used for construction by using the power of the hole drill rig. The drilling trajectory can be controlled while the drilling tool is rotating, thus realizing accurate, efficient and safe directional long hole drilling construction. It has the following advantages:

[0037] (1) High drilling efficiency. When the drill is directional drilling, the drilling power comes directly from the hole drill, which is transmitted to the push-type directional drill bit through the double-wall drill pipe and double-wall connector to perform rotary rock crushing. The output torque of the conventional screw drill is increased by more than 10 times, which can significantly increase the drilling speed.

[0038] (2) High drilling trajectory control accuracy. The drilling tool has a simple structure, which greatly shortens the distance between the measurement while drilling probe and the drill bit at the bottom of the hole, improves the measurement accuracy of the drilling trajectory, and provides a basis for accurate control of the drilling trajectory. At the same time, the drilling tool uses an internal drilling tool string connected in sequence by the inner drill rod of the double-wall drill rod, the connector core tube of the double-wall connector, and the directional distribution valve of the push-type directional drill bit to control the directional correction direction, and uses an external drilling tool string connected in sequence by the outer drill rod of the double-wall drill rod, the upper connector and the lower connector of the double-wall connector, and the drill body of the push-type directional drill bit to perform rotational rock crushing along the directional correction direction. The internal drilling tool string is not affected by the drilling reverse torque and has no reverse torsion angle. It can accurately control the directional correction direction and improve the trajectory control accuracy.

[0039] (3) High drilling safety. Different from the sliding deflection correction and rotational deflection stabilization in the past, the outer drill rod of the double-wall drill rod is in a rotating state when the drilling trajectory is corrected and stabilized. The rotary stirring of the outer drill rod and the turbulent flow of the large-flow flushing liquid are used to improve the drilling slag removal efficiency and ensure the safety of drilling construction. At the same time, the drilling tool of the present invention does not have a structural bend. When correcting the deviation, the push palm extends; when stabilizing the deviation, the palm retracts, reducing the force on the drilling tool and improving the safety of the drilling tool.

[0040] (4) Strong deep hole drilling capability. When the present invention performs drilling trajectory correction and stabilization, the outer drill rods of the double-wall drill rod are in a rotating state, and the frictional resistance acting on the double-wall drill rod is much smaller than the sliding drilling frictional resistance, which improves the drilling pressure transmission efficiency, ensures the drilling power at the bottom of the hole, and utilizes deep hole drilling. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0042] Figure 1 It is a schematic diagram of a rotary push-type near-drill bit measurement guide drilling tool in an underground coal mine.

[0043] Figure 2 It is a schematic diagram of double-wall drill pipe.

[0044] Figure 3 is a schematic diagram of a double wall connector.

[0045] Figure 4 It is a schematic diagram of a push-type directional drill bit.

[0046] Figure 5 It is a schematic diagram of a directional flow distribution valve.

[0047] Figure 6 It is a schematic diagram of the drilling method of the rotary push-type near-drill bit measurement guide drill tool in an underground coal mine.

[0048] The reference numbers and their meanings are as follows:

[0049] Double-wall drill pipe 1, double-wall connector 2, near-drill bit measuring probe 3, push-type directional drill bit 4, double female joint 11, thrust bearing A12, outer drill pipe 13, inner drill pipe 14, thrust bearing B15, locking nut A16, connector upper joint 21, locking nut B22, connector core tube 23, thrust bearing group 24, guide hole 25, connector lower joint 26, sealing body 27, drill bit body 41, distribution valve 42, Circlip 43, sealing ring A44, guide flow channel 45, fastening screw 46, cover 47, stabilizing flow channel 48, push-pull 49, distribution valve return spring 410, push-pull return spring 411, sealing ring B412, guide flow channel pressure relief hole 413, drill bit wing 414, drill bit water eye 415, flow limiting hole 421, sealing ring groove 422, valve port 423, base 424, borehole 5, formation 6. DETAILED DESCRIPTION

[0050] The following is a detailed description of the embodiments of the present invention by means of examples and in conjunction with the accompanying drawings. The examples are as follows:

[0051] See also Figure 1 , is a kind of coal mine underground rotary push-type near-drill-bit measurement guide drilling tool of the present invention, which is composed of a double-wall drill rod 1, a double-wall connector 2, a near-drill-bit measurement probe 3 and a push-type directional drill bit 4 connected in sequence. The near-drill-bit measurement probe 3 is installed in the connector core tube 23 of the double-wall connector 2, and can measure parameters such as borehole 5 trajectory parameters, formation 6 parameters, and the deflection direction of the push-type directional drill bit 4. The measurement data can be sent to the hole mouth by wired, mud pulse or electromagnetic wave transmission methods. According to the different measurement parameters and transmission methods, the length of the near-drill-bit measurement probe 3 can be changed; the borehole 5 trajectory parameters include inclination and azimuth; the formation 6 parameters include but are not limited to azimuth resistivity and azimuth gamma. The signal transmission modes of the near-drill-bit measurement probe 3 include wired, mud pulse and electromagnetic wave transmission.

[0052] See also Figure 2The double-wall drill pipe 1 includes an outer drill pipe 13, and also includes a double female joint 11, a thrust bearing A12, a thrust bearing B15, a locking nut A16 and an inner drill pipe 14 positioned in the outer drill pipe 13. The outer drill pipe 13 is connected by a threaded manner, and a female thread is arranged at the front end and a male thread is arranged at the rear end. Steps are arranged at the inner wall near the female thread and the root of the male thread; the outer diameter of the double female joint 11 is larger than that of the inner drill pipe 14, and a hexagonal female joint is arranged at the front end and a female thread is arranged at the rear end; the front end of the inner drill pipe 14 is provided with a male thread. The rear end is provided with a hexagonal male joint, and the root of the hexagonal male joint is provided with a male thread; the thrust bearing A12 is installed at the step at the root of the female thread of the outer drill rod 13; the thrust bearing B15 is installed at the step at the root of the male thread of the outer drill rod 13; the locking nut A16 is installed at the male thread at the root of the hexagonal male joint of the inner drill rod 14; the inner drill rod 14 is radially positioned in the outer drill rod 13 by the thrust bearing A12 and the thrust bearing B15, and is axially limited by the locking nut A16, and can rotate circumferentially relative to the outer drill rod 13, but cannot move axially. When the double-walled drill rods 1 are connected, the outer drill rods 13 are connected by threads, which can transmit both rotational power and forward power; the hexagonal female joint of the double female joint 11 and the hexagonal male joint of the inner drill rod 14 are plug-connected to each other, and only rotational power is transmitted. The surface shape of the outer drill rod 13 of the double-wall drill rod 1 can be selected according to the target formation to be drilled. When the target formation to be drilled is a medium-hard coal seam or rock formation, the outer surface is an outer flat circular structure; when the formation to be drilled is a broken soft coal seam, the outer surface is a spiral, triangular or triangular spiral or other special-shaped structures.

[0053] See also Figure 3The double-wall connector 2 includes an upper connector 21 and a lower connector 26 connected in sequence. Both ends of the upper connector 21 are female threads, the front end is connected to the male thread of the outer drill rod 13, and the rear end is connected to the lower connector 26, and a step is provided inside; both ends of the lower connector 26 are provided with male threads, the front end is connected to the upper connector 21, and the rear end is connected to the push-type directional drill bit 4, and a step is provided inside; the thrust bearing group 24 is installed between the upper connector 21 and the lower connector 26, and is limited by two steps. Position; the double-wall connector 2 is also provided with a connector core tube 23 inside, the front end of the connector core tube 23 is provided with a hexagonal female joint, the outer surface of the root of the hexagonal female joint is provided with a male thread, the rear end of the connector core tube 23 is provided with a hexagonal male joint, the root of the male joint is provided with a secondary step, the connector core tube 23 passes through the thrust bearing group 24, the rear end is limited by the first step at the root of the male joint, and the front end is limited by the locking nut B22 connected to the male thread at the root of the hexagonal female joint. It can rotate circumferentially relative to the connector upper joint 21 and the connector lower joint 26, but cannot move axially. The connector core tube 23 of the double-wall connector 2 is a hollow structure, and an instrument compartment for installing the near-drill-bit measuring probe 3 is arranged inside, and the length of the instrument compartment can be adjusted according to the length of the near-drill-bit measuring probe 3; a sealing body 27 is arranged at the second step at the root of the male joint of the connector core tube 23 to seal the gap between the connector core tube 23 and the connector lower joint 26; a guide hole 25 is radially arranged at the corresponding position of the connector core tube 23 and the thrust bearing group 24, which cooperates with the sealing body 27 to guide the annular gap flushing liquid between the inner drill rod 14 and the outer drill rod 13 of the double-wall drill rod 1 into the connector core tube 23.

[0054] See also Figure 4The push-to-pull directional drill bit 4 includes a drill body 41, the drill body 41 is a circular structure, the front end is provided with a female thread connected to the double-wall connector 2, and three rectangular grooves are evenly arranged in the middle of the outer surface along the radial direction. The rectangular groove is connected with a cover 47 by fastening screws 46 around it. A push-to-pull leg 49 is installed in the rectangular groove, and a push-to-pull leg return spring 411 is arranged between the push-to-pull leg 49 and the cover 47. The push-to-pull leg 49 can extend out of the cover 47 or retract into the rectangular groove. A sealing ring B412 is arranged between the rectangular groove and the push-to-pull leg 49; two Step hole, wherein the first step hole is a circular structure, and a spring groove is processed near the front end of the first step hole; the second step hole is a circular structure, and three guide flow channels 45 connected with the rectangular groove are evenly arranged along the radial direction near the front end of the second step hole; a directional flow distribution valve 42 is arranged in the first step, and the front end of the directional flow distribution valve 42 is limited by a spring 43 installed in the spring groove of the first step hole, and the rear end extends into the second step hole, and is limited by a directional flow distribution valve reset spring 410 installed in the second step hole; four drill bit wings 414 are processed at the rear end of the drill body 41. Three circular steady-inclination flow channels 48 parallel to the second step hole and connected with the first step hole are evenly arranged in the drill body 41 of the push-to-pull directional drill bit 4, and a drill bit water hole 415 is arranged at the rear end; pressure relief holes 413 are arranged at the bottom of the rectangular groove; the steady-inclination flow channels 48 and pressure relief holes 413 are both connected with the drill bit water hole 415. The outer contour of the push leg 49 of the push-type directional drill bit 4 is an arc shape and is inlaid with a diameter-protecting alloy.

[0055] See also Figure 5 The front end of the directional flow distribution valve 42 of the push-type directional drill bit 4 is provided with a hexagonal female joint, which is connected to the hexagonal male joint of the connector core tube 23. A step is provided at the root of the hexagonal female joint, which is limited by a retaining spring 43. A sealing ring groove 422 is provided on the step, in which a sealing ring A44 is installed; a flow limiting hole 421 with an axial blind hole is provided at the center of the directional flow distribution valve 42, and a valve port 423 is radially provided in the flow limiting hole 421. A spring base 424 is provided at the rear end of the directional flow distribution valve 42.

[0056] See also Figure 4 , Figure 5 The directional distribution valve 42 of the push-type directional drill bit 4 can move axially and rotate circumferentially along the drill bit body 41, but the maximum axial movement distance is less than the length of the hexagonal female joint of the directional distribution valve 42; when the directional distribution valve 42 moves downward and the valve port 423 completely enters the second step hole, the valve port 423 is connected to the guide flow channel 45 opposite to it, and is only connected to one guide flow channel 45; the valve port 423 of the directional distribution valve 42 is oriented in the direction of the push-type directional drill bit 4 to create a bevel.

[0057] See also Figure 1 to Figure 6A method for drilling a rotary push-type near-drill-bit measuring guide drill tool in a coal mine, comprising the following steps:

[0058] Step 1: Drilling tool connection. After completing the construction of the borehole casing section, install the push-to-pull directional drill bit 4, double-wall connector 2, near-drill bit measurement probe 3 and double-wall drill pipe 1 in sequence, and use the drilling rig to lower the rotating push-to-pull near-drill bit measurement guide drill tool to 0.5m from the bottom of the hole.

[0059] Step 2: Parameter measurement and directional drilling mode selection. Use the near-drill-bit measurement probe 3 to measure the trajectory parameters of the borehole 5, the formation 6 parameters and the deflection direction of the push-type directional drill bit 4, and select the directional drilling mode according to the deviation between the actual drilling trajectory of the borehole 5 and the designed trajectory and the formation 6 conditions.

[0060] Step 3: Directional drilling: Drilling 5 is performed according to the selected directional drilling mode, and the actual drilling trajectory is controlled to extend along the designed trajectory.

[0061] Step 4: Drilling is completed. Repeat steps 2 and 3 to drill hole 5 until the hole 5 reaches the designed depth, then withdraw the rotary push-type near-drill bit measuring guide drilling tool from the hole to complete the drilling of hole 5.

[0062] The directional drilling modes in step 2 include two types: a deflection correction drilling mode and a deflection stabilization drilling mode.

[0063] The specific basis for selecting the directional drilling mode in step 2 is: when the drilling formation 6 is the target formation and the deviation between the actual drilling trajectory of the borehole 5 and the designed trajectory is less than the maximum allowable deviation, the steady-inclination drilling mode is adopted; otherwise, the deflection correction drilling mode is adopted.

[0064] During the directional drilling in step 3, the deflection correction drilling mode includes the following sub-steps:

[0065] Step 1: Adjust the directional correction direction. Use the drilling rig to rotate the inner drill rod 14 of the double-wall drill rod 1, drive the connector core tube 23 of the double-wall connector 2 to rotate, and then drive the directional flow distribution valve 42 of the push-type directional drill bit 4 to rotate until the valve port 423 of the directional flow distribution valve 42 is in the same direction as the designed directional correction direction; lock the inner drill rod 14 to keep the valve port 423 of the directional flow distribution valve 42 unchanged.

[0066] Step 2: Directional deflection correction construction. High-pressure flushing fluid is injected from the double-wall drill pipe 1. Under the push of the high-pressure flushing fluid, the directional flow distribution valve reset spring 410 is compressed, the directional flow distribution valve 42 moves downward, and the valve port 423 enters the second step hole; the outer drill pipe 13 of the double-wall drill pipe 1 is pushed by the drilling rig to drive the push-type directional drill bit 4 to rotate and break the formation 6; during the rotation of the push-type directional drill bit 4, when the direction of the guide channel 45 is opposite to the valve port 423 of the directional flow distribution valve 42, the valve port 423 is connected to the corresponding guide channel 45, and the high-pressure flushing fluid is moved along the second step hole. The valve port 423 of the directional distribution valve 42 and the guide flow channel 45 enter the corresponding rectangular groove, push the corresponding push-against leg 49 to extend out of the cover 47, support it on the hole wall, and apply lateral force to the push-against directional drill bit 4. The other push-against legs 49 remain retracted, so that the push-against directional drill bit 4 is corrected in the set direction. After the action, the high-pressure flushing liquid flows out along the pressure relief hole 413 and the drill bit water hole 415. After cooling the directional drill bit, it carries the drill cuttings produced by drilling and flows out from the gap between the outer drill rod 13 of the double-wall drill rod 1 and the wall of the borehole 5.

[0067] Step 3: Reset the push-pull directional drill bit 4. After the directional correction is completed, stop injecting high-pressure flushing liquid into the double-wall drill pipe 1, the directional flow distribution valve 42 is reset under the action of the directional flow distribution valve reset spring 410, and the push-pull leg 49 is retracted into the rectangular groove under the action of the push-pull leg reset spring 411.

[0068] During the directional drilling in step three, the specific operation of the steady-inclination drilling mode is as follows: low-pressure flushing fluid is injected from the double-wall drill pipe 1, and the directional distribution valve 42 is under the action of the directional distribution valve reset spring 410, and the valve port 423 is still located in the first step hole, and the low-pressure flushing fluid flows out along the valve port 423 of the directional distribution valve 42, the steady-inclination flow channel 48, and the drill bit water hole 415. After cooling the directional drill bit, it carries the drill cuttings generated by drilling and flows out from the gap between the outer drill pipe 13 of the double-wall drill pipe 1 and the wall of the borehole 5; the double-wall drill pipe 1 is pushed by the drilling rig to drive the push-type directional drill bit 4 to rotate and crush the formation 6. At this time, the push-against palm 49 is kept in a retracted state under the action of the push-against palm reset spring 411, and no lateral thrust is generated, and no deflection is corrected in a fixed direction, and steady-inclination drilling is performed along the inclination and azimuth of the current borehole 5.

[0069] Although this article uses more double-wall drill pipe 1, double-wall connector 2, near-drill bit measuring probe 3, push-type directional drill bit 4, double female joint 11, thrust bearing A12, outer drill pipe 13, inner drill pipe 14, thrust bearing B15, locking nut A16, connector upper joint 21, locking nut B22, connector core tube 23, thrust bearing group 24, guide hole 25, connector lower joint 26, sealing body 27, drill bit body 41, distribution valve 42, retaining spring 43, The terms include sealing ring A44, guide channel 45, fastening screw 46, cover 47, stabilizing channel 48, push arm 49, distribution valve reset spring 410, push arm reset spring 411, sealing ring B412, guide channel pressure relief hole 413, drill bit fin 414, drill bit water hole 415, flow restriction hole 421, sealing ring groove 422, valve port 423, base 424, borehole 5, stratum 6, etc., but the possibility of using other terms is not excluded. These terms are used only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional restrictions is contrary to the spirit of the present invention.

Claims

1. A push-type directional drill bit, characterized in that: include: Drill bit body (41); Three rectangular grooves are evenly arranged along the outer surface of the drill bit body (41) in a radial direction and are connected to the drill bit water hole (415). A push leg (49) is arranged in the rectangular groove and can be pushed out of the rectangular groove by the fluid. A first cavity, disposed inside the drill bit body (41) and connected to the drill bit water hole (415) via a first flow channel; A second cavity is disposed inside the drill bit body (41) and is connected to the rectangular groove through a second flow channel; A directional flow distribution valve (42) comprising a valve body with a valve port (423), one end of the valve body sealing the first cavity; the valve port (423) is connected to the first cavity and the second cavity respectively as the valve body moves axially along the drill bit body (41); The first cavity and the second cavity are respectively a first step hole and a second step hole of two mutually connected circular structures; a retaining spring groove is provided on the inner wall of the first step hole; a directional flow distribution valve (42) is provided in the first step hole, one end of the directional flow distribution valve (42) is limited by a retaining spring (43) installed in the retaining spring groove, and the other end extends into the second step hole and is limited by a directional flow distribution valve return spring (410) installed in the second step hole; three guide flow channels (45) connected to the rectangular groove are evenly provided in the radial direction near the front end of the second step hole; and a hexagonal female joint is provided at the front end of the directional flow distribution valve (42); The directional flow distribution valve (42) of the push-type directional drill bit (4) can move axially and rotate circumferentially along the drill bit body (41), but the maximum axial movement distance is less than the length of the hexagonal female joint of the directional flow distribution valve (42); when the directional flow distribution valve (42) moves downward and the valve port (423) completely enters the second step hole, the valve port (423) is connected to the guide flow channel (45) opposite to it, and is only connected to one guide flow channel (45); the valve port (423) of the directional flow distribution valve (42) is oriented in the deflection direction of the push-type directional drill bit (4).

2. A push-type directional drill bit according to claim 1, characterized in that: include: The front end of the valve body is a cylindrical structure, a valve port (423) is provided on the cylindrical surface of the cylindrical structure, and one end of the cylinder extends into the second cavity and is limited by a return spring (410) provided in the second cavity.

3. A push-type directional drill bit according to claim 1, characterized in that: include: The rectangular groove is provided with a cover (47), the bottom end of the pushing leg is provided with a protruding portion, and a compression spring is provided between the protruding portion and the cover.

4. A push-type directional drill bit according to claim 1, characterized in that: The rectangular groove is connected to the drill bit water hole (415) through the guide flow channel pressure relief hole (413).

5. The push-type directional drill bit according to claim 1, characterized in that: The first flow channel comprises a circular steady-inclination flow channel (48) which is evenly arranged in the drill bit body (41), parallel to the second step hole and connected to the first step hole.

6. A push-type directional drilling tool, comprising the push-type directional drill bit according to claim 1.

7. A push-type directional drilling tool according to claim 6, characterized in that: Also includes: A double-wall connector (2) is used to connect the push-type directional drill bit (4) and the drill rod; the double-wall connector (2) comprises an upper connector joint (21) and a lower connector joint (26) connected to each other, a thrust bearing group (24), and a connector core tube (23); the thrust bearing group (24) is adjusted between the upper connector joint (21) and the lower connector joint (26) and is limited by the step surfaces of the upper connector joint (21) and the lower connector joint (26); the connector core tube (23) passes through the thrust bearing group (24) and can rotate circumferentially relative to the upper connector joint (21) and the lower connector joint (26).

8. The push-type directional drilling tool according to claim 7, characterized in that: Also includes: A double-wall drill rod (1) connected to the push-type directional drill bit (4); The invention comprises an inner drill rod (14) and an outer drill rod (13); connecting threads are arranged at both ends of the outer drill rod (13); an outer drill rod step surface is arranged at the root of the thread; a thrust bearing is arranged at the outer drill rod step surface; and the inner drill rod (14) is positioned inside the outer drill rod (13) via the thrust bearing.

9. A push-type directional drilling method, characterized in that: The method is implemented by using the push-type directional drilling tool according to any one of claims 6 to 8, comprising: Flushing liquid is introduced into a rectangular groove arranged on the outer surface of the drill head body (41), and the flushing liquid is used to drive a pushing leg (49) arranged in the rectangular groove to extend out of the rectangular groove to adjust the drilling direction.

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