Drilling tool and method for full-length insertion of fracturing casing into underground directional borehole

Abstract

The present disclosure provides a drilling tool and a method for full-length insertion of a fracturing casing into an underground directional borehole. The drilling tool comprises a reaming bit, a torque-transmitting casing, a torque-transmitting shaft, and a pilot bit; the reaming bit is provided with a first through hole; the torque-transmitting casing and the reaming bit are coaxially arranged, and the reaming bit is connected to one end of the torque-transmitting casing; the other end of the torque-transmitting casing is provided with a first connecting portion, the inner wall of the torque-transmitting casing is provided with a keyway and a separation guide groove, and the separation guide groove is communicated with the keyway; the torque-transmitting shaft passes through the first through hole and the torque-transmitting casing; the outer wall of the torque-transmitting shaft is provided with a torque-transmitting member, one end of the torque-transmitting shaft is provided with a second connecting portion, the pilot bit is connected to the other end of the torque-transmitting shaft, and the outer diameter of the pilot bit is less than the inner diameters of the first through hole and the torque-transmitting casing. The drilling tool of the present application allows large-bore fracturing casings to be inserted into directional boreholes, reducing the cost of fracturing engineering, and facilitating high-flow and high-pressure hydraulic fracturing operations.

Description

Full-process running method of drilling tools and downhole directional drilling fracturing casing

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority and benefits of Chinese patent application with application number 202410107971X and application date January 25, 2024. The entire contents of the above-mentioned Chinese patent application are hereby incorporated by reference into this application. Technical Field

[0003] The present invention relates to the technical field of downhole hydraulic fracturing construction, and in particular to a drilling tool and a method for running downhole directional drilling fracturing casing throughout the entire process. Background Art

[0004] In recent years, underground directional drilling and segmented hydraulic fracturing technology in coal mines has made great progress. Due to the large amount of coal mine fracturing projects and high project costs, improving fracturing technology, improving fracturing work efficiency, and reducing fracturing project costs have become important technical research and development directions.

[0005] In related technologies, the fracturing hole sections that act simultaneously in the fracturing borehole are long, and the flow rate requirements of the high-pressure water system are very high. The large-diameter fracturing casing is not easy to be directly lowered into the directional drill hole.

[0006] Summary of the Invention

[0007] The present disclosure aims to solve one of the technical problems in the related art at least to a certain extent.

[0008] To this end, an embodiment of the present disclosure proposes a drilling tool that can lower a large-diameter fracturing casing into a directional borehole, simplifies the operation steps, reduces the process difficulty and construction workload, and improves construction efficiency.

[0009] The embodiments of the present disclosure also provide a method for running a downhole directional drilling fracturing casing throughout the entire process.

[0010] The drilling tool of the embodiment of the present disclosure includes:

[0011] a reaming drill bit having a first through hole;

[0012] A torque transmission sleeve, the torque transmission sleeve being coaxially arranged with the reaming drill bit, and the reaming drill bit being connected to one end of the torque transmission sleeve, the other end of the torque transmission sleeve being provided with a first connecting portion, the inner wall of the torque transmission sleeve being provided with a keyway and a separation guide groove, the separation guide groove being in communication with the keyway;

[0013] a torque transmission shaft, the torque transmission shaft being inserted into the first through hole and the torque transmission sleeve, a torque transmission member being provided on an outer wall of the torque transmission shaft, and a second connecting portion being provided at one end of the torque transmission shaft;

[0014] a pilot drill bit connected to the other end of the torque transmission shaft and located in front of the reaming drill bit to guide the drilling direction of the reaming drill bit, wherein the outer diameter of the pilot drill bit is smaller than the inner diameter of the first through hole and the torque transmission sleeve;

[0015] When the reaming drill is drilling, the torque transmission member is located in the keyway and abuts against one of the side walls of the keyway to drive the torque transmission shaft to rotate synchronously with the torque transmission sleeve. When the reaming drill stops working, the torque transmission shaft is rotated to allow the torque transmission member to enter the separation guide groove and separate from the torque transmission sleeve through the separation guide groove.

[0016] The drilling tool of the embodiment of the present disclosure can run a large-diameter fracturing casing into a directional drill hole, and simplifies the operation steps, reduces the process difficulty and construction workload, and improves construction efficiency.

[0017] In some embodiments, the keyway has a first opening toward the reaming drill bit, the separation guide groove has a second opening away from the reaming drill bit, and the sidewalls of the keyway and the sidewalls of the separation guide groove are connected to form a Z-shaped groove body; and / or

[0018] The reaming drill bit is connected to the torque transmission sleeve via a thread, and one end of the reaming drill bit close to the keyway abuts against the first opening of the keyway; and / or

[0019] The torque transmission shaft is connected to the pilot drill bit via a threaded connection; and / or

[0020] A sealing ring is provided between the outer wall of the torque transmission shaft and the inner wall of the torque transmission sleeve, and / or between the outer wall of the torque transmission shaft and the inner wall of the first through hole.

[0021] According to an embodiment of the present disclosure, a method for running a downhole directional drilling fracturing casing throughout the entire process includes the following steps:

[0022] Constructing a directional drill hole and washing the directional drill hole, and fixing a sealing casing at the orifice section of the directional drill hole;

[0023] Connecting a drilling tool to the front end of the first section of the fracturing casing near the bottom of the directional drill hole, wherein the drilling tool is the drilling tool described in the above embodiment, inserting one end of the fracturing casing equipped with the drilling tool into the directional drill hole, and using a drilling rig to drive the fracturing casing and the drilling tool for rotary drilling, and pulling the fracturing casing into the directional drill hole;

[0024] Connecting other sections of fracturing casing at the rear end of the first section of fracturing casing until the first section of fracturing casing reaches the bottom of the directional drilled hole;

[0025] Salvaging the torque transmission shaft and the pilot drill bit of the drilling tool so that the annular grouting channel between the outer wall of the fracturing casing and the inner wall of the directional drill hole is connected to the inner cavity of the fracturing casing;

[0026] Flushing the annular grouting channel between the outer wall of the fracturing casing and the inner wall of the directional drill hole;

[0027] Injecting grout into the annular grouting channel to fill the annular grouting channel to complete the fixing of the fracturing casing;

[0028] Clean the inner hole of the fracturing casing.

[0029] The method for running a fracturing casing through the entire process of downhole directional drilling in the disclosed embodiment utilizes a fracturing casing instead of a drill pipe. During the reaming drilling process of the directional drilling, a fracturing casing with a large diameter is run into a deeper directional borehole, thereby improving operation efficiency, reducing the cost and construction workload of the fracturing project, and increasing the flow area of ​​the run-in fracturing casing. In the subsequent hydraulic fracturing process, a large flow and high-pressure water flow can be provided, thereby improving the fracturing effect.

[0030] In some embodiments, salvaging the torque transmission shaft and the guide drill bit of the drilling tool includes the following steps:

[0031] Connect a salvage taper to one end of the drill pipe;

[0032] Using a drilling rig to deliver the drill pipe and the salvage cone through the inner hole of the fracturing casing to the bottom of the directional drill hole;

[0033] The salvage male cone is connected to the second connection portion of the torque transmission shaft, the torque transmission shaft is driven to rotate in the opposite direction, and the torque transmission shaft and the pilot drill bit are fished out through the drill rod and the salvage male cone.

[0034] In some embodiments, the sealing sleeve has a first flange and a flushing and grouting port, wherein the first flange is provided at an end of the sealing sleeve away from the directional drill hole, and the flushing and grouting port is provided on the side wall of the sealing sleeve in a section located outside the directional drill hole;

[0035] After the fracturing casing in the first section reaches the bottom of the directional drill hole, the following steps are also included:

[0036] A second flange is provided at the end of the fracturing casing located at the orifice of the directional drill hole, and the first flange is connected to the second flange to form an annular grouting channel between the fracturing casing and the inner wall of the sealing casing, and between the fracturing casing and the inner wall of the directional drill hole.

[0037] In some embodiments, the length of the sealing casing in the section of the directional drill hole is 7m-14m.

[0038] In some embodiments, in the step of connecting other segments of fracturing casing at the rear end of the first segment of the fracturing casing, a first casing is connected after part of the fracturing casing, and the outer wall of the first casing has spirally arranged protrusions.

[0039] In some embodiments, two adjacent fracturing sleeves and the first sleeve and the fracturing sleeves located at the front and rear ends of the first sleeve are connected by threads; and / or

[0040] The extension trajectory of the protrusion on the outer wall of the first sleeve is a right-handed spiral line; and / or

[0041] There are multiple first casings, and the multiple first casings are arranged at intervals in the extension direction of the directional drilling hole, and the interval between the previous first casing and the next first casing is 15m-25m.

[0042] In some embodiments, in the step of connecting the fracturing casing of other sections at the rear end of the first section of the fracturing casing, a second casing is connected after part of the fracturing casing, and a plurality of barbs are provided on the circumference of the outer wall of the second casing. The barbs extend from the outer wall of the second casing to the inner wall of the directional drill hole, and the barbs are inclined toward the end of the second casing away from the bottom of the directional drill hole.

[0043] In some embodiments, the barbs are elastic sheets; and / or

[0044] The barb abuts against the inner wall of the directional drill hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] FIG1 is a schematic structural diagram of a drilling tool (with a torque transmission casing viewed from perspective) according to an embodiment of the present disclosure.

[0046] FIG2 is a schematic cross-sectional view of the drilling tool according to an embodiment of the present disclosure.

[0047] FIG3 is a schematic diagram of the structure of the torsion transmission shaft in an embodiment of the present disclosure.

[0048] FIG4 is a schematic diagram of the structure of the torque transmission sleeve in an embodiment of the present disclosure.

[0049] FIG5 is a flow chart of a method for running a downhole directional drilling fracturing casing throughout an embodiment of the present disclosure.

[0050] FIG6 is a schematic structural diagram of a sealing sleeve in an embodiment of the present disclosure.

[0051] FIG7 is a schematic structural diagram of a fracturing casing in an embodiment of the present disclosure.

[0052] FIG8 is a schematic structural diagram of the first sleeve in an embodiment of the present disclosure.

[0053] FIG9 is a schematic structural diagram of the second sleeve in an embodiment of the present disclosure.

[0054] FIG10 is a schematic diagram of the connection structure of the fracturing casing, the first casing, and the second casing in an embodiment of the present disclosure.

[0055] FIG11 is a schematic diagram of the connection structure between the second flange and the fracturing casing in an embodiment of the present disclosure.

[0056] FIG12 is a schematic diagram of the arrangement of the fracturing casing before punching the annulus grouting channel in an embodiment of the present disclosure.

[0057] FIG13 is a schematic cross-sectional view of the fracturing casing before punching the annulus grouting channel in an embodiment of the present disclosure.

[0058] FIG14 is a schematic diagram of the annular grouting channel after grouting in an embodiment of the present disclosure.

[0059] FIG15 is a schematic diagram of the structure of the fracturing casing and the drill tool when they are lowered into the directional drilling hole according to an embodiment of the present disclosure.

[0060] FIG16 is a schematic diagram of grouting of the annular grouting channel in an embodiment of the present disclosure.

[0061] Figure numerals: 100, drilling tool; 11, reaming drill bit; 12, torque transmission casing; 121, keyway; 1211, first opening; 122, separation guide groove; 1221, second opening; 123, third opening; 124, first connecting part; 13, torque transmission shaft; 131, torque transmission member; 132, sealing ring; 133, second connecting part; 14, pilot drill bit; 2, fracturing casing; 21, male thread; 22, female thread; 3, first casing; 31, protrusion; 4, second casing; 41, barb; 5, sealing casing; 51, first flange; 52, flushing grouting port; 6, second flange; 7, directional drilling; 71, annulus grouting channel; 8, salvage male cone. DETAILED DESCRIPTION

[0062] The embodiments of the present disclosure are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present disclosure, but should not be understood as limiting the present disclosure.

[0063] As shown in FIG1-FIG4 , the drilling tool 100 according to the embodiment of the present disclosure includes a reaming drill bit 11 , a torque transmission sleeve 12 , a torque transmission shaft 13 and a pilot drill bit 14 .

[0064] The reaming drill bit 11 has a first through hole. The torque transmission sleeve 12 is coaxially arranged with the reaming drill bit 11, and the reaming drill bit 11 is connected to one end of the torque transmission sleeve 12. The other end of the torque transmission sleeve 12 is provided with a first connecting portion 124. The inner wall of the torque transmission sleeve 12 is provided with a keyway 121 and a separation guide groove 122, and the separation guide groove 122 is connected to the keyway 121. It should be understood that the first connecting portion 124 of the torque transmission sleeve 12 is used to connect with the fracturing sleeve 2, and then the fracturing sleeve 2, the torque transmission sleeve 12, and the reaming drill bit 11 are driven by the drilling rig to achieve reaming drilling. The fracturing sleeve 2 can be lowered while the directional drilling 7 is being reamed.

[0065] The torque transmission shaft 13 is disposed within the first through hole and the torque transmission sleeve 12. A torque transmission member 131 is provided on the outer wall of the torque transmission shaft 13. A second connecting portion 133 is provided at one end of the torque transmission shaft 13. A pilot drill bit 14 is connected to the other end of the torque transmission shaft 13. The pilot drill bit 14 is positioned in front of the reaming drill bit 11 to guide the drilling direction of the reaming drill bit 11. The outer diameter of the pilot drill bit 14 is smaller than the inner diameter of the first through hole and the torque transmission sleeve 12. It should be understood that when no longer constrained by the torque transmission member 131, the keyway 121, and the separation guide groove 122, the pilot drill bit 14 and the torque transmission shaft 13 can be disengaged from the first through hole and the inner cavity of the torque transmission sleeve 12, thereby achieving separation of the pilot drill bit 14 and the torque transmission shaft 13 from the torque transmission sleeve 12.

[0066] When the reaming drill bit 11 is drilling, the torque transmission member 131 is located in the keyway 121 and abuts against one side wall of the keyway 121 to drive the torque transmission shaft 13 to rotate synchronously with the torque transmission sleeve 12. At this time, the torque transmission member 131 abuts against one side wall of the keyway 121, thereby realizing torque transmission. When the reaming drill bit 11 stops working, the torque transmission shaft 13 is rotated to make the torque transmission member 131 enter the separation guide groove 122 and pass through the separation guide groove 122. 2 is separated from the torque transmission sleeve 12. At this time, the torque transmission member 131 can enter the separation guide groove 122 through the communication port between the separation guide groove 122 and the torque transmission sleeve 12, and is no longer constrained by the end of the keyway 121 away from the reaming drill bit 11. The torque transmission member 131 can be separated from the torque transmission sleeve 12 from the separation guide groove 122. As the torque transmission shaft 13 is further pulled, the torque transmission shaft 13 and the pilot drill bit 14 can be completely separated from the torque transmission sleeve 12.

[0067] The drilling tool 100 of the embodiment of the present disclosure can lower a large-diameter fracturing casing 2 into a directional borehole 7 , simplifying the operation steps, reducing the process difficulty and construction workload, and improving construction efficiency.

[0068] As shown in FIG4 , in some embodiments, the keyway 121 has a first opening 1211 facing the reaming drill bit 11, and the separation guide groove 122 has a second opening 1221 facing away from the reaming drill bit 11. The side walls of the keyway 121 and the side walls of the separation guide groove 122 are connected to form a Z-shaped groove body. It should be understood that the keyway 121 and the separation guide groove 122 form a Z-shaped groove body, and the Z-shaped groove body has a first opening 1211 and a second opening 1221 at both ends in the axial direction of the torque transmission sleeve 12. During assembly, the torque transmission member 131 can enter the keyway 121 through the first opening 1211. When the torque transmission sleeve 12 rotates in the forward direction, one of the side walls of the keyway 121 abuts against the torque transmission member 131, thereby realizing the transmission of torque between the torque transmission sleeve 12 and the torque transmission shaft 13. The other side wall of the groove 121 is connected to the separation guide groove 122 through the third opening 123. Therefore, when the torque transmission sleeve 12 does not rotate, the torque transmission member 131 can enter the separation guide groove 122 through the third opening 123 by rotating the torque transmission sleeve 12. By pulling back the torque transmission shaft 13, the torque transmission member 131 can be separated from the Z-shaped groove through the second opening 1221, thereby eliminating interference between the torque transmission shaft 13 and the guide drill bit 14 and the torque transmission sleeve and the reaming drill bit 11, thereby achieving separation.

[0069] The forward rotation in the above embodiment is the drilling direction of the reaming drill bit 11 during the drilling operation.

[0070] Optionally, the reaming drill bit 11 is connected to the torque transmission sleeve 12 by a threaded connection, and the end of the reaming drill bit 11 close to the keyway 121 abuts against the first opening 1211 of the keyway 121. During the forward rotation drilling process of the torque transmission sleeve 12, the reaming drill bit 11 can block the first opening 1211 to prevent the torque transmission member 131 from disengaging from the keyway 121 from the first opening 1211.

[0071] Optionally, the torque transmission shaft 13 and the guide drill bit 14 are connected by threads to facilitate the connection between the torque transmission shaft 13 and the guide drill bit 14. For example, the torque transmission shaft 13 and the guide drill bit 14 are connected by a male cone and a female cone, that is, a conical external thread segment is provided on one of them, and a conical internal thread segment is provided on the other, and the conical external thread segment and the conical internal thread segment are connected together.

[0072] Optionally, a sealing ring 132 is provided between the outer wall of the torque transmission shaft 13 and the inner wall of the torque transmission sleeve 12, and / or between the outer wall of the torque transmission shaft 13 and the inner wall of the first through hole. The setting of the sealing ring 132 can seal the front end of the drill bit 100, thereby preventing powder and slag generated during the drilling process from entering the torque transmission sleeve 12 and the fracturing sleeve 2 connected to the rear end of the torque transmission sleeve 12.

[0073] Furthermore, in the embodiment of the present disclosure, a Z-shaped recessed groove is opened on the inner wall of the torque transmission sleeve 12 to form a connected keyway 121 and a separation guide groove 122, or a plurality of plates are welded and fixed on the inner wall of the torque transmission sleeve 12 to define the Z-shaped recessed groove using the plurality of plates.

[0074] Furthermore, a plurality of Z-shaped recessed grooves are arranged at intervals along the circumferential direction on the inner wall of the torque transmission sleeve 12 , and a plurality of torque transmission members 131 are also provided on the outer wall of the torque transmission shaft 13 .

[0075] Furthermore, the torque transmission member 131 is integrally formed with the torque transmission shaft 13 , and the torque transmission member 131 protrudes from the outer wall surface of the torque transmission shaft 13 , or the torque transmission member 131 is a key, which is welded and fixed to the torque transmission shaft 13 .

[0076] As shown in FIG1 to FIG16 , the method for running the fracturing casing 2 throughout the downhole directional drilling 7 according to an embodiment of the present disclosure includes the following steps:

[0077] S101, construct a directional drill hole 7 and wash the directional drill hole 7, fix the sealing casing 5 at the hole mouth section of the directional drill hole 7, specifically, after the sealing casing 5 is lowered into the directional drill hole 7, inject the pipe-fixing cement slurry between the outer wall of the sealing casing 5 and the inner wall of the directional drill hole 7, and fill the area between the sealing casing 5 and the hole wall of the directional drill hole 7, after the cement slurry solidifies, the sealing casing 5 forms a whole with the hole wall, so that the sealing casing 5 is fixed in the directional drill hole 7.

[0078] The provision of the sealing casing 5 not only improves the structural strength of the orifice section of the directional drilling hole 7, but also facilitates the subsequent hole washing and grouting operations, thereby avoiding problems such as water leakage and grout leakage at the port of the directional drilling hole 7.

[0079] The directional drilling hole 7 is a pilot drilling hole, which is expanded by the drilling tool 100 to facilitate the running of the fracturing casing 2.

[0080] S102. Connect a drilling tool 100 to the front end of the first section of the fracturing casing 2 near the bottom of the directional borehole 7. The drilling tool 100 is the drilling tool 100 in the above embodiment. Insert one end of the fracturing casing 2 equipped with the drilling tool 100 into the directional borehole 7. Use a drilling rig to drive the fracturing casing 2 and the drilling tool 100 for rotary drilling, and pull the fracturing casing 2 into the directional borehole 7. It should be understood that by arranging the drilling tool 100 on the fracturing casing 2 and using the fracturing casing 2 instead of the traditional drill pipe, the drilling rig can be used to drive the fracturing casing 2 and the drilling tool 100 for drilling. During the drilling process, the drilling tool 100 can expand the directional borehole 7 and pull the fracturing casing 2 into the directional borehole 7.

[0081] In the embodiment of the present disclosure, by connecting the drill tool 100 to the fracturing casing 2, the large-diameter fracturing casing 2 can be easily lowered into a deeper directional borehole 7, which helps to achieve high-flow, high-pressure hydraulic fracturing operations, improve the fracturing effect, and reduce the engineering workload and engineering cost of hydraulic fracturing construction.

[0082] S103: Connect other sections of fracturing casing 2 at the rear end of the first section of fracturing casing 2 until the first section of fracturing casing 2 reaches the bottom of the directional borehole 7. When the first section of fracturing casing 2 continues to penetrate into the directional borehole 7 as the drilling tool 100 drills, other fracturing casings 2 are connected to the rear end of the first section of fracturing casing 2 until the first section of fracturing casing 2 reaches the bottom of the directional borehole 7. At this time, the running of the fracturing casing 2 is completed, and multiple sections of fracturing casing 2 are connected in sequence, thereby forming a hydraulic fracturing channel.

[0083] Both ends of the fracturing sleeve 2 respectively have an external thread section and an internal thread section, that is, a male thread 21 and a female thread 22 . The internal thread section on one of the two adjacent fracturing sleeves 2 is matched and engaged with the external thread section on the other.

[0084] S104, the torque transmission shaft 13 and the pilot drill bit 14 of the fishing drilling tool 100 are pulled out to connect the annular grouting channel 71 between the outer wall of the fracturing casing 2 and the inner wall of the directional drill hole 7 with the inner cavity of the fracturing casing 2;

[0085] S105. Flushing the annular grouting channel 71 between the outer wall of the fracturing casing 2 and the inner wall of the directional borehole 7. It should be understood that powder and slag will be generated during the drilling process of the drill tool 100. When the fracturing casing 2 reaches the bottom of the directional borehole 7 along with the drill tool 100, the powder and slag will fill the space between the outer wall of the fracturing casing 2 and the inner wall of the directional borehole 7, affecting the subsequent pipe fixing construction. Therefore, it is necessary to flush the annular grouting channel 71 between the outer wall of the fracturing casing 2 and the inner wall of the directional borehole 7. After the powder and slag flushing is completed, it can be ensured that the subsequent cement slurry fully and evenly fills the annular grouting channel 71.

[0086] S106: Grouting is injected into the annular grouting channel 71 to fill the annular grouting channel 71 to complete the fixing of the fracturing casing 2. After the cement slurry filled in the annular grouting channel 71 solidifies, the fracturing casing 2 can be fixed in the directional drill hole 7, ensuring the stability of the operation during the hydraulic fracturing operation.

[0087] S107, cleaning the inner hole of the fracturing casing 2. Since some cement slurry will enter the inner hole of the fracturing casing 2 during the grouting process of the annular grouting channel 71, it is necessary to clean the inner hole of the fracturing casing 2. For example, a cleaning drill bit with a radial size slightly smaller than that of the fracturing casing 2 is arranged in the fracturing casing 2. The cleaning drill bit is driven by the drilling rig and drill pipe to clean the inner hole of the fracturing casing 2 to ensure that the interior of the fracturing casing 2 is unobstructed and provide a water flow channel for subsequent high-flow fracturing. Water can be injected into the fracturing casing 2 during the cleaning process to facilitate the discharge of the cleaned slag from the fracturing casing 2.

[0088] The method for lowering the fracturing casing 2 throughout the downhole directional drilling hole 7 of the disclosed embodiment utilizes the fracturing casing 2 instead of the drill pipe. During the expansion drilling process of the directional drilling hole 7, the fracturing casing 2 with a large diameter is lowered into the deeper directional drilling hole 7, thereby improving the operation efficiency, reducing the cost and construction workload of the fracturing project, and increasing the flow area of ​​the lowered fracturing casing 2. In the subsequent hydraulic fracturing process, it can provide a large flow and high pressure water flow, thereby improving the fracturing effect.

[0089] As shown in Figures 1 to 4, the drilling tool 100 of the embodiment of the present disclosure includes a torque transmission casing 12, a reaming drill bit 11, a guide drill bit 14 and a torque transmission shaft 13. The end of the torque transmission casing 12 close to the bottom of the directional borehole 7 is connected to the reaming drill bit 11, and the end of the torque transmission casing 12 away from the bottom of the directional borehole 7 is connected to the fracturing casing 2. The outer diameter of the reaming drill bit 11 is larger than the outer diameter of the fracturing casing 2, so that the directional borehole 7 can be expanded and the fracturing casing 2 is easily pulled into the directional borehole 7. At the same time, it can also ensure that an annular grouting channel 71 is formed between the inner wall of the directional borehole 7 and the outer wall of the fracturing casing 2.

[0090] The torque transmission shaft 13 is used to connect the torque transmission sleeve 12. The torque is transmitted between the two through the torque transmission member 131 and the keyway 121, that is, key transmission. During the drilling process of the fracturing sleeve 2 and the reaming drill bit 11, the torque transmission shaft 13 can rotate synchronously. The pilot drill bit 14 is arranged at the end of the torque transmission shaft 13 close to the bottom of the directional borehole 7, which can make the pilot drill bit 14 rotate synchronously with the reaming drill bit 11. The pilot drill bit 14 is closer to the bottom of the directional borehole 7 than the reaming drill bit 11. The pilot drill bit 14 can play a guiding role to ensure that the drilling direction of the reaming drill bit 11 is the same as the extension direction of the pilot drill bit 14. The outer diameter of the pilot drill bit 14 is smaller than the inner diameter of the first through hole and the torque transmission sleeve 12, which facilitates the subsequent salvage of the pilot drill bit 14.

[0091] Furthermore, in order to prevent dust and debris from entering the fracturing casing 2 during drilling, a sealing ring 132 is provided between the torque transmission shaft 13 and the inner wall of the first through hole to achieve end sealing of the inner cavity of the fracturing casing 2 .

[0092] In some embodiments, the torque transmission shaft 13 and the pilot drill bit 14 of the salvage drilling tool 100 include the following steps:

[0093] S201. Connect a salvage taper 8 to one end of the drill pipe. Before flushing the annular grouting channel 71, it is necessary to ensure that the annular grouting channel 71 and the inner bore of the fracturing casing 2 are unobstructed to improve the flushing effect. Therefore, the salvage taper 8 is provided and the torque transmission shaft 13 and the pilot drill bit 14 are removed from the fracturing casing 2 using the drill pipe and the salvage taper 8.

[0094] S202, use the drilling rig to deliver the drill pipe and salvage cone 8 to the bottom of the directional borehole 7 through the inner hole of the fracturing casing 2. Use the drilling rig to deliver the drill pipe and salvage cone 8 to the bottom of the directional borehole 7, and connect the salvage cone 8 to the torque transmission shaft 13.

[0095] S203 , connecting the salvage male cone 8 to the second connection portion 133 of the torque transmission shaft 13 , driving the torque transmission shaft 13 to rotate in the opposite direction, and fishing out the torque transmission shaft 13 and the pilot drill bit 14 through the drill pipe and the salvage male cone 8 .

[0096] Specifically, a male cone is provided at the end of the salvage male cone 8, and a female cone is provided at the end of the torque transmission shaft 13. After the male cone and the female cone are connected, the drill pipe, the salvage male cone 8, the torque transmission shaft 13 and the guide drill bit 14 form an integrated structure. When the drill pipe is rotated, the torque transmission part 131 of the torque transmission shaft 13 enters the separation guide groove 122 from the key groove 121. By pulling back the drill pipe, the salvage male cone 8, the torque transmission shaft 13 and the guide drill bit 14 are brought out of the fracturing casing 2.

[0097] As shown in Figures 6, 12 and 13, in some embodiments, the sealing sleeve 5 has a first flange 51 and a flushing and grouting port 52. The first flange 51 is arranged at the end of the sealing sleeve 5 away from the directional drill hole 7, and the flushing and grouting port 52 is arranged on the side wall of the sealing sleeve 5 in the section located outside the directional drill hole 7.

[0098] After the step of performing the steps until the first section of the fracturing casing 2 reaches the bottom of the directional borehole 7, the following steps are also included: a second flange 6 is set at the end of the fracturing casing 2 located at the orifice of the directional borehole 7, and the first flange 51 and the second flange 6 are connected to form an annular grouting channel 71 between the fracturing casing 2 and the inner wall of the sealing casing 5, and between the fracturing casing 2 and the inner wall of the directional borehole 7.

[0099] It should be understood that by setting a second flange 6 at the end of the fracturing casing 2 located at the orifice of the directional drill hole 7, the second flange 6 can be connected to the first flange 51. At this time, an annular grouting channel 71 can be formed between the fracturing casing 2 and the inner wall of the sealing casing 5, and between the fracturing casing 2 and the inner wall of the directional drill hole 7, and the flushing grouting port 52 is connected to the annular grouting channel 71, which facilitates the flushing and grouting operations of the annular grouting channel 71 through the flushing grouting port 52.

[0100] Optionally, the second flange 6 is welded to the fracturing sleeve 2 , or the second flange 6 has a connecting sleeve provided with a threaded section of a male thread or a female thread, and the second flange 6 is connected to the fracturing sleeve 2 via threads.

[0101] Optionally, an end sleeve can be set, a second flange 6 is set at one end of the end sleeve, and a threaded section of a male thread or a female thread is set at the other end of the end sleeve. After the first section of the fracturing sleeve 2 reaches the bottom of the directional borehole 7, the end sleeve is connected to the fracturing sleeve 2 located in the directional borehole 7, and then the second flange 6 is connected to the first flange 51 together.

[0102] In some embodiments, the length of the section of the sealing casing 5 located in the directional borehole 7 is 7m-14m. It should be understood that when the length of the section of the sealing casing 5 that penetrates into the directional borehole 7 is less than 7m, it is easy to cause insufficient structural stability between the sealing casing 5 and the directional borehole 7, affecting the structural stability of the sealing section. When the length of the section of the sealing casing 5 that penetrates into the directional borehole 7 is greater than 14m, it will result in an excessively long construction length, making construction difficult. The length of the section of the sealing casing 5 located in the directional borehole 7 in the disclosed embodiments can be 7m, 7.5m, 8m, 9.3m, 10m, 11.6m, 13m, or 14m.

[0103] As shown in Figures 7 to 10, in some embodiments, in the step of connecting other sections of fracturing casing 2 at the rear end of the first section of fracturing casing 2, a first casing 3 is connected after the partial fracturing casing 2, and the outer wall of the first casing 3 has a spirally arranged protrusion 31.

[0104] It should be understood that the first sleeve 3 is a spiral guide, specifically including a first tube body, a spiral-shaped protrusion 31 is provided on the outer wall of the first tube body, a male thread 21 is provided at one end of the first tube body, and a female thread 22 is provided at the other end of the first tube body. The protrusion 31 is fixed to the outer wall of the first tube body by welding. By arranging the first sleeve 3 at intervals, the fracturing sleeve 2 can be guided. At the same time, during the rotation of the first sleeve 3, the spiral-shaped protrusion 31 is used to push the powder slag toward the orifice.

[0105] Furthermore, two adjacent fracturing sleeves 2 and the first sleeve 3 and the fracturing sleeves 2 located at the front end and the rear end of the first sleeve 3 are connected by threads.

[0106] Specifically, in the extension direction of the directional drilling hole 7, since the two ends of the fracturing casing 2 are respectively provided with a male thread 21 and a female thread 22, the two adjacent fracturing casings 2 connected to each other are connected by a threaded connection. When the first casing 3 is arranged between the two fracturing casings 2, the male thread 21 of the first casing 3 is connected to the female thread 22 of the front fracturing casing 2, and the female thread 22 of the first casing 3 is connected to the male thread 21 of the rear fracturing casing 2, so that the first casing 3 can be arranged between the two adjacent fracturing casings 2, ensuring that the fracturing casings 2 can be connected, and the first casing 3 can be used for auxiliary guidance of the fracturing casing 2.

[0107] Furthermore, the extension trajectory of the protrusion 31 on the outer wall of the first casing 3 is a right-handed spiral line. At this time, when the drilling rig drives the fracturing casing 2 and the first casing 3 to rotate, the right-handed spiral line can be used to drive the powder and slag in the directional drill hole 7 to move toward the orifice of the directional drill hole 7, thereby facilitating the subsequent flushing operation of the annulus grouting channel 71.

[0108] In some embodiments, there are multiple first casings 3, and the multiple first casings 3 are arranged at intervals in the extension direction of the directional drilling hole 7, and the spacing between the previous first casing 3 and the next first casing 3 is 15m-25m. It should be noted that the embodiment of the present disclosure is used for the lowering of the fracturing casing 2 in a long borehole, so it is necessary to achieve the guidance of the fracturing casing 2 by arranging multiple first casings 3 at intervals. Specifically, according to the requirements of the rotation and guidance of the fracturing casing 2 in the directional drilling hole 7, the spacing distance between two adjacent first casings 3 is set to 15m-25m, and the spacing distance between two adjacent first casings 3 can be 15m, 16m, 18.5m, 19.3m, 21m, 23.6m, 24.7m or 25m. When the interval between two adjacent first casings 3 is less than 15m, the adjacent first casings 3 are too close, which has no obvious improvement effect on the movement and guidance of the fracturing casing 2, and will cause slow construction progress. Excessive use of the first casing 3 will also lead to increased costs. When the interval between two adjacent first casings 3 is greater than 25m, it is easy to cause the distance between the adjacent first casings 3 to be too far, and some fracturing casings 2 cannot be guided, affecting the subsequent flushing of the annulus grouting channel 71 and the grouting and fixing operations of the fracturing casing 2.

[0109] As shown in Figures 7 to 10, in some embodiments, in the step of connecting the fracturing casing 2 of other sections at the rear end of the first section of the fracturing casing 2, a second casing 4 is connected after the partial fracturing casing 2, and a plurality of barbs 41 are provided on the circumference of the outer wall of the second casing 4. The barbs 41 extend from the outer wall of the second casing 4 to the inner wall of the directional borehole 7, and the barbs 41 are inclined toward the end of the second casing 4 away from the bottom of the directional borehole 7.

[0110] It should be understood that the second casing 4 is a casing with hanging barbs 41, specifically including a second tube body, and a plurality of barbs 41 are arranged circumferentially on the outer wall of the second tube body, one end of the second tube body is provided with a male thread 21, and the other end is provided with a female thread 22. When the second casing 4 is connected between the fracturing casings 2, the male thread 21 at the front end of the second casing 4 is connected with the female thread 22 on the front fracturing casing 2, and the female thread 22 at the rear end of the second casing 4 is connected with the male thread 21 on the rear fracturing casing 2. The plurality of barbs 41 are welded on the outer wall of the second tube body in a trumpet-shaped opening structure. In the process of the fracturing casing 2 drilling into the directional borehole 7, the barbs 41 can fit tightly together with the hole wall of the directional borehole 7 and can be hooked on the hole wall to prevent the fracturing casing 2 from sliding down in the upward inclined borehole with a large angle, thereby ensuring that the fracturing casing 2 can be drilled stably, improving the efficiency of lowering the fracturing casing 2 in the downhole directional borehole 7, and reducing the difficulty of operation.

[0111] In some embodiments, the barbs 41 are elastic sheets that abut against the inner wall of the directional drill hole 7. It should be understood that the barbs 41 are elastic sheets with a certain degree of elasticity. When the elastic sheet abuts against the inner wall of the directional drill hole 7, the barbs 41 will undergo elastic deformation during the lowering of the fracturing casing 2, which will not affect the movement of the fracturing casing 2 toward the bottom of the directional drill hole 7. When drilling in an upwardly inclined hole at a large angle, the fracturing casing 2 will move downward due to its own gravity. At this time, the barbs 41 can hook on the wall of the directional drill hole 7, thereby preventing the fracturing casing 2 from sliding toward the opening of the directional drill hole 7, thereby ensuring the safety of the operation.

[0112] The number of the barbs 41 on the second tube body is at least 3, for example, the number of the barbs 41 on the second tube body is 3, 4 or 5, and the plurality of barbs 41 are evenly distributed along the circumference of the second tube body.

[0113] The method for lowering the fracturing casing 2 throughout the downhole directional drilling hole 7 of the disclosed embodiment can be applied to directional drilling holes 7 with a length of hundreds of meters or thousands of meters. For example, it can be applied to directional drilling holes 7 with a depth of 500m, 600m, 750m, 800m, 930m, 1100m, and 1500m. It can ensure that the depth of the directional drilling hole 7 meets the range of hydraulic fracturing, thereby reducing the engineering workload of hydraulic fracturing in coal mines, improving operating efficiency, and providing a large flow of high-pressure water to ensure the fracturing effect and reduce engineering costs.

[0114] As shown in Figures 15 and 16, the following takes an upward inclined directional long borehole with a depth of 800 meters and an inclination of 35 degrees as an example to explain in detail the construction steps of the entire lowering of 7 large-flow fracturing casings 2 and grouting to fix the hole in the directional drilling of a coal mine underground, mainly including the lowering of the sealing casing 5 at the borehole mouth, flushing of the borehole, reaming of the bottom expansion drill 100 and the subsequent lowering of the fracturing casing 2, connection of the rotary guide, connection of the hanging barb 41 casing, removal of the guide drill bit 14, cleaning of the annulus grouting channel 71, grouting of the fracturing casing 2 and the annulus channel of the hole wall, and cleaning of the inner hole of the fracturing casing 2.

[0115] Step 1: After directional long drilling is completed, a sealing casing 5 is lowered into the borehole. The diameter of the sealing casing 5 is 168 mm, and the inner bore is 154 mm. The outer portion of the borehole is equipped with a first flange 51 and a flushing and grouting port 52, which is equipped with a valve. Pipe-fixing cement is injected between the outer wall of the sealing casing 5 and the borehole wall, solidifying the sealing casing 5 and the borehole wall into one.

[0116] Step 2: Borehole flushing is to use the drill rig to complete the drilling to the required depth before starting to insert the fracturing casing 2. A large amount of flushing water is then passed through the drill pipe to the bottom of the borehole to fully flush the borehole to ensure that there is no excessive drill cuttings in the hole to hinder the insertion of the fracturing casing 2.

[0117] Step 3: As shown in Figure 15, after the sealing casing 5 is secured, the drill tool 100 is installed on the male thread 21 of the first section of the fracturing casing 2, and subsequent fracturing casings 2 are connected in sequence. The fracturing casing 2 equipped with the drill tool 100 is fed into the sealing casing 5 using a drilling rig. After the drill tool 100 is lowered into the hole, the drill rig is used to perform rotary drilling, and subsequent fracturing casings 2 are lowered into the hole in sequence. During the rotary drilling process of the fracturing casing 2, the pilot drill bit 14 at the front end of the drill tool 100 guides the drilling, and the reaming drill bit 11 expands the borehole wall to provide a channel for the fracturing casing 2 to be lowered.

[0118] During the rotational lowering of the fracturing casing 2, a rotary guide (first casing 3), also known as a spiral guide, is installed at 20-meter intervals. The male thread 21 of the rotary guide connects to the female thread 22 of the preceding fracturing casing 2, and the female thread 22 of the rotary guide connects to the male thread 21 of the succeeding fracturing casing 2. The rotary guide and fracturing casing 2 are connected as a whole, ensuring concentricity between the fracturing casing 2 and the borehole, providing ample grout flow for subsequent grouting and pipe fixing.

[0119] During the rotational lowering of the fracturing casing 2, a second casing 4, namely a hanging barb 41 casing, is installed at intervals. The male thread 21 of the hanging barb 41 casing is connected to the female thread 22 of the front section of the fracturing casing 2, and the female thread 22 of the hanging barb 41 casing is connected to the male thread 21 of the rear section of the fracturing casing 2. The hanging barb 41 casing and the fracturing casing 2 are connected as a whole. The barbs 41 are integrated with the borehole wall, suspending the fracturing casing 2 in the borehole, preventing the fracturing casing 2 from sliding down during the rotary drilling of the fracturing casing 2 by the drilling rig.

[0120] Step 4: After all the fracturing casings 2 are lowered into the directional borehole 7, the salvage cone 8 is sent to the bottom of the hole using a drilling rig, so that the salvage cone 8 is connected to the torque transmission shaft 13 in the drill tool 100 at the bottom of the hole, and the pilot drill bit 14 at the front end of the drill tool 100 is salvaged, so that the inner hole of the fracturing casing 2 and the annular grouting channel 71 between the fracturing casing 2 and the directional borehole 7 are connected, forming a smooth channel.

[0121] Step 5: After all fracturing casings 2 are lowered into the hole, flushing water is injected from the inner bore of the fracturing casing 2 to the hole bottom to clean the pipe channel (i.e., the annular grouting channel 71). A large amount of flushing water is injected from the inner bore of the fracturing casing 2 to the hole bottom and then flows out from the annular cavity between the outer wall of the fracturing casing 2 and the borehole wall, fully flushing the pipe channel to ensure that the channel is unobstructed for subsequent grouting.

[0122] Step 6: After flushing the fixed-pipe grouting channel, connect the fracturing casing 2 and the sealing casing 5 at the orifice. The fracturing casing 2 at the orifice is equipped with a second flange 6; the sealing casing 5 at the orifice is equipped with a first flange 51 and a flushing and grouting port 52, with a valve installed at the flushing and grouting port 52. The fracturing casing 2 with the second flange 6 and the sealing casing 5 at the orifice are connected and fastened together via the flanges. The annular cavity between the outer wall of the fracturing casing 2 and the inner wall of the sealing casing 5 is connected to the annular cavity between the outer wall of the fracturing casing 2 and the wall of the directional drilled hole 7, forming a channel for fixed-pipe grouting.

[0123] Step 7: As shown in Figure 16, after the fracturing casing 2 and the sealing casing 5 are connected and tightened, the pipe-fixing cement slurry is injected into the annulus cavity between the fracturing casing 2 and the sealing casing 5 from the flushing grouting port 52 on the sealing casing 5. By continuously injecting cement slurry into the hole, the cement slurry flows from the grouting annulus channel to the bottom of the hole until the cement slurry overflows from the inner hole of the fracturing casing 2, that is, the entire pipe-fixing annulus cavity is filled with cement slurry, and the grouting and pipe-fixing is completed.

[0124] Step 8: After grouting and consolidation, use a drill to clean the solidified cement from the inner bore of the fracturing casing 2. The outer diameter of the drill bit used to clean the cement from the fracturing casing 2 is smaller than the inner bore diameter of the fracturing casing 2. After cleaning, the fracturing casing 2 meets the requirements of high-flow, high-pressure hydraulic fracturing.

[0125] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present disclosure and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present disclosure.

[0126] 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 being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. Throughout the present disclosure, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0127] In this disclosure, unless otherwise expressly specified or limited, terms such as "mounted," "connected," "connect," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integration; mechanical connections, electrical connections, or communication between them; direct connections or indirect connections through an intermediate medium; and internal communication between two elements or interaction between two elements, unless otherwise expressly limited. Those skilled in the art will understand the specific meanings of the above terms in this disclosure based on specific circumstances.

[0128] In the present disclosure, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0129] In the present disclosure, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0130] Although the embodiments of the present disclosure have been shown and described above, it is understood that the above embodiments are illustrative and are not to be construed as limitations on the present disclosure. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present disclosure.

Claims

1. A drilling tool comprising: a reaming drill bit having a first through hole; A torque transmission sleeve, the torque transmission sleeve being coaxially arranged with the reaming drill bit, and the reaming drill bit being connected to one end of the torque transmission sleeve, the other end of the torque transmission sleeve being provided with a first connecting portion, the inner wall of the torque transmission sleeve being provided with a keyway and a separation guide groove, the separation guide groove being in communication with the keyway; a torque transmission shaft, the torque transmission shaft being passed through the first through hole and the torque transmission sleeve, a torque transmission member being provided on an outer wall of the torque transmission shaft, and a second connecting portion being provided at one end of the torque transmission shaft; a pilot drill bit connected to the other end of the torque transmission shaft and located in front of the reaming drill bit to guide the drilling direction of the reaming drill bit, wherein the outer diameter of the pilot drill bit is smaller than the inner diameter of the first through hole and the torque transmission sleeve; When the reaming drill is drilling, the torque transmission member is located in the keyway and abuts against one of the side walls of the keyway to drive the torque transmission shaft to rotate synchronously with the torque transmission sleeve. When the reaming drill stops working, the torque transmission shaft is rotated to allow the torque transmission member to enter the separation guide groove and separate from the torque transmission sleeve through the separation guide groove.

2. The drill string according to claim 1, wherein, The keyway has a first opening facing the reaming drill bit, the separation guide groove has a second opening facing away from the reaming drill bit, and the sidewalls of the keyway and the sidewalls of the separation guide groove are connected to form a Z-shaped groove body; and / or The reaming drill bit is connected to the torque transmission sleeve via a thread, and one end of the reaming drill bit close to the keyway abuts against the first opening of the keyway; and / or The torque transmission shaft is connected to the pilot drill bit via a threaded connection; and / or A sealing ring is provided between the outer wall of the torque transmission shaft and the inner wall of the torque transmission sleeve and / or between the outer wall of the torque transmission shaft and the inner wall of the first through hole.

3. A method for running a downhole directional drilling fracturing casing throughout the entire process, comprising the following steps: Constructing a directional drill hole and washing the directional drill hole, and fixing a sealing casing at the orifice section of the directional drill hole; Connecting a drilling tool to the front end of the first section of the fracturing casing near the bottom of the directional drill hole, wherein the drilling tool is the drilling tool according to claim 1 or 2, inserting one end of the fracturing casing equipped with the drilling tool into the directional drill hole, and using a drilling rig to drive the fracturing casing and the drilling tool for rotary drilling, and pulling the fracturing casing into the directional drill hole; Connecting other sections of fracturing casing at the rear end of the first section of fracturing casing until the first section of fracturing casing reaches the bottom of the directional drilled hole; Salvaging the torque transmission shaft and the pilot drill bit of the drilling tool so that the annular grouting channel between the outer wall of the fracturing casing and the inner wall of the directional drill hole is connected to the inner cavity of the fracturing casing; Flushing the annular grouting channel between the outer wall of the fracturing casing and the inner wall of the directional drill hole; Injecting grout into the annular grouting channel to fill the annular grouting channel to complete the fixing of the fracturing casing; Clean the inner hole of the fracturing casing.

4. The method for running downhole directional drilling fracturing casing throughout the entire process according to claim 3, wherein: Said salvaging of the torque transmission shaft and the guide drill bit of said drilling tool comprises the following steps: Connect a salvage taper to one end of the drill pipe; Using a drilling rig to deliver the drill pipe and the salvage cone through the inner hole of the fracturing casing to the bottom of the directional drill hole; The salvage male cone is connected to the second connection portion of the torque transmission shaft, the torque transmission shaft is driven to rotate in the opposite direction, and the torque transmission shaft and the pilot drill bit are fished out through the drill rod and the salvage male cone.

5. The method for running downhole directional drilling fracturing casing throughout the entire process according to claim 3, wherein: The sealing sleeve has a first flange and a flushing and grouting port, wherein the first flange is provided at an end of the sealing sleeve away from the directional drill hole, and the flushing and grouting port is provided on the side wall of the sealing sleeve in a section outside the directional drill hole; After the fracturing casing in the first section reaches the bottom of the directional drill hole, the following steps are also included: A second flange is provided at the end of the fracturing casing located at the orifice of the directional drill hole, and the first flange is connected to the second flange to form an annular grouting channel between the fracturing casing and the inner wall of the sealing casing, and between the fracturing casing and the inner wall of the directional drill hole.

6. The method for running downhole directional drilling fracturing casing throughout the entire process according to claim 3 or 5, wherein: The length of the sealing casing section located in the directional drill hole is 7m-14m.

7. The downhole directional drilling and fracturing casing full-length lowering method according to claim 3, wherein, In the step of connecting the fracturing casings of other sections at the rear end of the first section of the fracturing casing, a first casing is connected after part of the fracturing casing, and the outer wall of the first casing has spirally arranged protrusions.

8. The method for running downhole directional drilling fracturing casing throughout the entire process according to claim 7, wherein: The adjacent two fracturing sleeves and the first sleeve and the fracturing sleeves located at the front and rear ends of the first sleeve are connected by threads; and / or The extension trajectory of the protrusion on the outer wall of the first sleeve is a right-handed spiral line; and / or There are multiple first casings, and the multiple first casings are arranged at intervals in the extension direction of the directional drilling hole, and the interval between the previous first casing and the next first casing is 15m-25m.

9. The method for fully lowering the downhole directional drilling and fracturing casing according to claim 3, wherein, In the step of connecting the fracturing casing of other sections at the rear end of the first section of the fracturing casing, a second casing is connected after part of the fracturing casing, and a plurality of barbs are provided on the circumference of the outer wall of the second casing. The barbs extend from the outer wall of the second casing to the inner wall of the directional drilled hole, and the barbs are inclined toward the end of the second casing away from the bottom of the directional drilled hole.

10. The downhole directional drilling and fracturing casing full-length running method according to claim 9, wherein, The barbs are elastic sheets; and / or The barb abuts against the inner wall of the directional drill hole.

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