Drilling tool and method for running a downhole directional drilling and fracturing casing

Abstract

The application discloses a drilling tool and a full-path running method of a downhole directional drilling fracturing casing, and the drilling tool comprises a reaming bit, a torque transmission casing, a torque transmission shaft body and a pilot bit, the reaming bit is provided with a first through hole; the torque transmission casing is coaxially arranged with the reaming bit, and the reaming bit is connected to one end of the torque transmission casing; the other end of the torque transmission casing is provided with a first connecting part; the inner wall of the torque transmission casing is provided with a key groove and a separation guide groove, and the separation guide groove and the key groove are communicated; the torque transmission shaft body is arranged in the first through hole and the torque transmission casing; the outer wall of the torque transmission shaft body is provided with a torque transmission piece; one end of the torque transmission shaft body is provided with a second connecting part; the pilot bit is connected to the other end of the torque transmission shaft body; and the outer diameter size of the pilot bit is smaller than the inner diameter size of the first through hole and the torque transmission casing. The drilling tool disclosed by the application can run a large-diameter fracturing casing into a directional drilling hole, reduces the fracturing engineering cost, and facilitates the hydraulic fracturing construction with large flow and high pressure.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of downhole hydraulic fracturing construction, and particularly relates to a drilling tool and a method for full-path running of a downhole directional drilling fracturing casing. BACKGROUND

[0002] In recent years, the directional drilling staged hydraulic fracturing technology in coal mines has made great progress. Since the fracturing engineering quantity is large and the engineering cost is high, improving the fracturing technology, improving the fracturing work efficiency and reducing the fracturing engineering cost have become important technical research and development directions.

[0003] The problem of the fracturing technology in the related art is that the simultaneously acting fracturing hole section in the long drilling hole is too long, and the flow rate of the high-pressure water system is very high. The drilling tool in the related art cannot directly run the large-diameter fracturing casing into the directional drilling hole, so that the fracturing construction equipment is large and the process is complex, and it is difficult to be widely popularized and applied. SUMMARY

[0004] The present application aims to at least partially solve one of the technical problems in the related art.

[0005] To this end, the embodiments of the present application propose a drilling tool which can run a large-diameter fracturing casing into a directional drilling hole, and simplifies the operation steps, reduces the process difficulty and construction quantity, and improves the construction efficiency.

[0006] The embodiments of the present application also propose a method for full-path running of a downhole directional drilling fracturing casing.

[0007] The drilling tool of the embodiments of the present application comprises:

[0008] The reaming bit has a first through hole;

[0009] The torque transmission casing is coaxially arranged with the reaming bit, and the reaming bit is connected to one end of the torque transmission casing. The other end of the torque transmission casing is provided with a first connecting portion. The inner wall of the torque transmission casing is provided with a key groove and a separation guide groove, and the separation guide groove and the key groove are in communication.

[0010] The torque transmission shaft body is arranged in the first through hole and the torque transmission casing. The outer wall of the torque transmission shaft body is provided with a torque transmission member. One end of the torque transmission shaft body is provided with a second connecting portion.

[0011] The guide bit is connected to the other end of the torque transmission shaft body, and the guide bit is located in front of the reaming bit to guide the drilling direction of the reaming bit. The outer diameter size of the guide bit is smaller than the inner diameter size of the first through hole and the torque transmission casing.

[0012] In the reaming drill bit drilling operation, the torque transmission member is located in the key groove and abuts against one side wall of the key groove to drive the torque transmission shaft body to rotate synchronously with the torque transmission sleeve, and in the reaming drill bit stop operation, the torque transmission shaft body is rotated to make the torque transmission member enter the separation guide groove and separate from the torque transmission sleeve through the separation guide groove.

[0013] The drilling tool of the embodiment of the present application can lower a large-diameter fracturing sleeve into a directional borehole, simplifies operation steps, reduces process difficulty and construction amount, and improves construction efficiency.

[0014] In some embodiments, the key groove 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 side wall of the key groove and the side wall of the separation guide groove are connected to form a Z-shaped groove body; and / or

[0015] The reaming drill bit is connected with the torque transmission sleeve through threads, and an end of the reaming drill bit close to the key groove abuts at the first opening of the key groove; and / or

[0016] The torque transmission shaft body is connected with the pilot drill bit through threads; and / or

[0017] A sealing ring is arranged between the outer wall of the torque transmission shaft body and the inner wall of the torque transmission sleeve, and / or between the outer wall of the torque transmission shaft body and the inner wall of the first through hole.

[0018] The downhole directional borehole fracturing sleeve whole-process lowering method according to the embodiment of the present application comprises the following steps:

[0019] A directional borehole is constructed and the directional borehole is washed, and a hole sealing sleeve is fixed at a hole opening section of the directional borehole;

[0020] A drill tool is connected to a front end of a first section fracturing sleeve close to a hole bottom of the directional borehole, the drill tool is the drill tool in the above-mentioned embodiments, one end of the fracturing sleeve provided with the drill tool is sent into the directional borehole, the fracturing sleeve and the drill tool are rotated and drilled by a drilling machine, and the fracturing sleeve is pulled into the directional borehole;

[0021] Other section fracturing sleeves are connected in sequence at a rear end of the first section fracturing sleeve until the first section fracturing sleeve reaches the hole bottom of the directional borehole;

[0022] The torque transmission shaft body and the pilot drill bit of the drill tool are fished out to make an annular grouting passage between the outer wall of the fracturing sleeve and the inner wall of the directional borehole connected with the inner cavity of the fracturing sleeve;

[0023] The annular grouting passage between the outer wall of the fracturing sleeve and the inner wall of the directional borehole is flushed.

[0024] Grouting into the annular grouting passage to fill the annular grouting passage, so as to complete the pipe fixing of the fracturing casing;

[0025] Cleaning the inner hole of the fracturing casing.

[0026] The downhole directional drilling fracturing casing whole-process running method of the embodiment of the application uses a fracturing casing to replace a drill rod, and in the process of directional drilling reaming drilling, a large-diameter fracturing casing is run into a deeper directional drilling hole, operation construction efficiency is improved, fracturing engineering cost and construction engineering quantity are reduced, and the flow area of the run-in fracturing casing is improved. In the subsequent hydraulic fracturing process, a large flow and high pressure flow can be provided to improve the fracturing effect.

[0027] In some embodiments, the fishing of the torque transmission shaft body and the pilot bit includes the following steps:

[0028] A fishing male taper is connected to one end of the drill rod;

[0029] The drill rod and the fishing male taper are sent to the bottom of the directional drilling hole through the inner hole of the fracturing casing by using a drilling machine;

[0030] The fishing male taper is connected to the second connection part of the torque transmission shaft body, the torque transmission shaft body is driven to rotate reversely, and the torque transmission shaft body and the pilot bit are fished out through the drill rod and the fishing male taper.

[0031] In some embodiments, the hole sealing casing has a first flange and a flushing grouting port, the first flange is arranged at one end of the hole sealing casing away from the directional drilling hole, and the flushing grouting port is arranged on the side wall of the section of the hole sealing casing located outside the directional drilling hole;

[0032] After the fracturing casing reaches the bottom of the directional drilling hole in step 1, the method further includes the following steps:

[0033] A second flange is arranged at the end of the fracturing casing located at the orifice of the directional drilling hole, the first flange and the second flange are connected to form an annular grouting passage between the inner wall of the fracturing casing and the hole sealing casing and between the inner wall of the fracturing casing and the directional drilling hole.

[0034] In some embodiments, the length of the section of the hole sealing casing located in the directional drilling hole is 7m-14m.

[0035] In some embodiments, the fracturing casing of the other section is connected in the fracturing casing connection of the rear end of the fracturing casing of step 1, and a first casing is connected after part of the fracturing casing, the outer wall of the first casing has a protruding part arranged in a spiral.

[0036] In some embodiments, the two adjacent fracturing casings are connected by threads; and / or

[0037] The extension trajectory of the protrusions on the outer wall of the first casing is a right-handed helix; and / or

[0038] The first casing is a plurality of casings, and the plurality of casings are arranged at intervals in the extension direction of the directional borehole, and the interval between the front casing and the rear casing is 15-25 m.

[0039] In some embodiments, the step of connecting the fracturing casings in sequence is performed at the rear end of the first section of the fracturing casings, and a second casing is connected to the rear end of the first section of the fracturing casings, and the outer wall of the second casing is provided with a plurality of barbs extending from the outer wall of the second casing to the inner wall of the directional borehole, and the barbs are inclined towards the end of the second casing away from the bottom of the directional borehole.

[0040] In some embodiments, the barb is a flexible sheet; and / or

[0041] The barb abuts against the inner wall of the directional borehole. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 is a structural schematic diagram of a drill tool (perspective view of torque transmission casing) of an embodiment of the present application.

[0043] Figure 2 is a structural schematic diagram of a drill tool (perspective view of torque transmission casing) of an embodiment of the present application.

[0044] Figure 3 is a structural schematic diagram of a torque transmission shaft body of an embodiment of the present application.

[0045] Figure 4 is a structural schematic diagram of a torque transmission casing of an embodiment of the present application.

[0046] Figure 5 is a flowchart of a method for full-path running of a downhole directional borehole fracturing casing of an embodiment of the present application.

[0047] Figure 6 is a structural schematic diagram of a hole sealing casing of an embodiment of the present application.

[0048] Figure 7 is a structural schematic diagram of a fracturing casing of an embodiment of the present application.

[0049] Figure 8 is a structural schematic diagram of a first casing of an embodiment of the present application.

[0050] Figure 9 is a structural schematic diagram of a second casing in an embodiment of the present application.

[0051] Figure 10 is a structural schematic diagram of a connection of the fracturing casing, the first casing and the second casing in an embodiment of the present application.

[0052] Figure 11 is a structural schematic diagram of a connection of the second flange and the fracturing casing in an embodiment of the present application.

[0053] Figure 12 is a structural schematic diagram of the fracturing casing before punching of the annular grouting passage in an embodiment of the present application.

[0054] Figure 13 is a sectional view of the fracturing casing before punching of the annular grouting passage in an embodiment of the present application.

[0055] Figure 14 is a structural schematic diagram of the fracturing casing after grouting of the annular grouting passage in an embodiment of the present application.

[0056] Figure 15 is a structural schematic diagram of the fracturing casing and the drilling tool in a directional drilling process in an embodiment of the present application.

[0057] Figure 16 is a structural schematic diagram of the fracturing casing in a grouting process of the annular grouting passage in an embodiment of the present application.

[0058] Reference signs:

[0059] 100, drilling tool;

[0060] 11, reamer; 12, torque transmission casing; 121, key groove; 1211, first opening; 122, separation guide groove; 1221, second opening; 123, third opening; 124, first connecting part; 13, torque transmission shaft body; 131, torque transmission member; 132, sealing ring; 133, second connecting part; 14, pilot bit;

[0061] 2, fracturing casing; 21, male thread; 22, female thread;

[0062] 3, first casing; 31, protruding part;

[0063] 4, second casing; 41, barb;

[0064] 5, hole sealing casing; 51, first flange; 52, flushing and grouting port;

[0065] 6, second flange;

[0066] 7, directional drilling; 71, annular grouting passage;

[0067] 8, fishing male cone. DETAILED DESCRIPTION

[0068] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0069] like Figures 1-4 As shown, the drill bit 100 of this embodiment includes a reaming drill bit 11, a torque transmission sleeve 12, a torque transmission shaft 13, and a guide drill bit 14.

[0070] 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 part 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 and the keyway 121 are connected. It should be understood that the first connecting part 124 of the torque transmission sleeve 12 is used to connect with the fracturing casing 2, so that the fracturing casing 2, the torque transmission sleeve 12 and the reaming drill bit 11 are driven by the drilling rig to achieve the reaming drilling effect. While performing reaming drilling of the directional drilling 7, the fracturing casing 2 can be lowered.

[0071] The torque transmission shaft 13 passes through the first through hole and the torque transmission sleeve 12. The outer wall of the torque transmission shaft 13 is provided with a torque transmission element 131. One end of the torque transmission shaft 13 is provided with a second connecting part 133. A guide drill bit 14 is connected to the other end of the torque transmission shaft 13, and the guide drill bit 14 is located in front of the reaming drill bit 11 to guide the drilling direction of the reaming drill bit 11. The outer diameter of the guide 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, without the constraints of the torque transmission element 131, the keyway 121, and the separation guide groove 122, the guide drill bit 14 and the torque transmission shaft 13 can be disengaged from the inner cavity of the first through hole and the torque transmission sleeve 12, thereby achieving the separation of the guide drill bit 14 and the torque transmission shaft 13 from the torque transmission sleeve 12.

[0072] When the reaming bit 11 is in operation, the torque transmission member 131 is located in the key groove 121 and abuts against one side wall of the key groove 121 to drive the torque shaft 13 to rotate synchronously with the torque sleeve 12, at this time, the torque transmission member 131 abuts against one side wall of the key groove 121, so that the torque transmission can be achieved, when the reaming bit 11 stops operation, the torque shaft 13 is rotated to make the torque transmission member 131 enter the separation guide groove 122 and separate from the torque sleeve 12 through the separation guide groove 122, at this time, the torque transmission member 131 can enter the separation guide groove 122 through the communication opening of the separation guide groove 122 and the torque sleeve 12, and then is not constrained by the end of the key groove 121 away from the reaming bit 11, so that the torque transmission member 131 can be separated from the torque sleeve 12 in the separation guide groove 122, and the torque shaft 13 and the pilot bit 14 can be completely separated from the torque sleeve 12 by further pulling the torque shaft 13.

[0073] The drilling tool 100 of the embodiment of the present application can lower the large-diameter fracturing sleeve 2 into the directional borehole 7, and simplifies the operation steps, reduces the process difficulty and construction amount, and improves the construction efficiency.

[0074] As shown in Figure 4 In some embodiments, the key groove 121 has a first opening 1211 facing the reaming bit 11, the separation guide groove 122 has a second opening 1221 facing away from the reaming bit 11, and the side wall of the key groove 121 and the side wall of the separation guide groove 122 are communicated to form a Z-shaped groove body. It should be understood that the key groove 121 and the separation guide groove 122 form a Z-shaped groove body, and the Z-shaped groove body has the first opening 1211 and the second opening 1221 at two ends in the axial direction of the torque sleeve 12, respectively, when assembled, the torque transmission member 131 can enter the key groove 121 through the first opening 1211, when the torque sleeve 12 rotates forward, one side wall of the key groove 121 abuts against the torque transmission member 131, so that the torque transmission between the torque sleeve 12 and the torque shaft 13 is achieved, the other side wall of the key groove 121 is communicated with the separation guide groove 122 through the third opening 123, therefore, when the torque 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 sleeve 12, and the torque transmission member 131 can be separated from the Z-shaped groove body through the second opening 1221 by pulling back the torque shaft 13, so that the torque shaft 13 and the pilot bit 14 are not interfered with the torque sleeve and the reaming bit 11, and separation is achieved.

[0075] The forward rotation in the above embodiment is the drilling direction of the reaming bit 11 in the drilling operation.

[0076] Optionally, the reaming drill bit 11 is connected to the torque transmission sleeve 12 by a thread. The end of the reaming drill bit 11 near 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 component 131 from disengaging from the first opening 1211 from the keyway 1211.

[0077] 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 tapered external thread section is provided on one of them, and a tapered internal thread section is provided on the other. The tapered external thread section and the tapered internal thread section are connected together.

[0078] 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 sealing ring 132 can seal the front end of the drill bit 100, preventing the dust and slag generated during drilling from entering the torque transmission sleeve 12 and the fracturing sleeve 2 connected to the rear end of the torque transmission sleeve 12.

[0079] Furthermore, in this embodiment of the invention, a Z-shaped groove is formed on the inner wall of the torsion transmission sleeve 12 to form a connected keyway 121 and a separation guide groove 122, or multiple plates are welded and fixed on the inner wall of the torsion transmission sleeve 12 to define the Z-shaped groove.

[0080] Furthermore, multiple Z-shaped grooves are arranged circumferentially on the inner wall of the torque transmission sleeve 12, and multiple torque transmission components 131 are also provided on the outer wall of the torque transmission shaft 13.

[0081] Furthermore, the torque transmission component 131 is integrally formed with the torque transmission shaft 13, and the torque transmission component 131 protrudes from the outer wall surface of the torque transmission shaft 13, or the torque transmission component 131 is a key, which is welded and fixed to the torque transmission shaft 13.

[0082] like Figures 1-16 As shown, the method for running the fracturing casing 2 through the downhole directional drilling 7 according to an embodiment of the present invention includes the following steps:

[0083] S101. Construct directional drilling 7 and clean the directional drilling 7. Fix the sealing sleeve 5 at the opening section of the directional drilling 7. Specifically, after the sealing sleeve 5 is lowered into the directional drilling 7, inject the pipe-solidifying cement grout between the outer wall of the sealing sleeve 5 and the inner wall of the directional drilling 7, and fill the area between the sealing sleeve 5 and the hole wall of the directional drilling 7. After the cement grout solidifies, the sealing sleeve 5 forms an integral part with the hole wall, so that the sealing sleeve 5 is fixed in the directional drilling 7.

[0084] By arranging the hole sealing sleeve 5, the structural strength of the orifice section of the directional drilling hole 7 can be improved, and the hole washing and grouting operations in the later stage are facilitated, thereby avoiding water leakage and grout leakage at the port of the directional drilling hole 7.

[0085] The directional drilling hole 7 is a pilot hole, and the hole is expanded by the drilling tool 100, so that the fracturing sleeve 2 is lowered.

[0086] S102, the drilling tool 100 is connected to the front end of the first section of the fracturing sleeve 2 close to the hole bottom of the directional drilling hole 7, the drilling tool 100 is the drilling tool 100 in the above embodiment, the end of the fracturing sleeve 2 provided with the drilling tool 100 is sent into the directional drilling hole 7, the fracturing sleeve 2 and the drilling tool 100 are driven to rotate and drill by the drilling machine, and the fracturing sleeve 2 is pulled into the directional drilling hole 7. It should be understood that by arranging the drilling tool 100 on the fracturing sleeve 2, the fracturing sleeve 2 is used instead of the traditional drill rod, so that the fracturing sleeve 2 and the drilling tool 100 can be driven to drill by the drilling machine, and the drilling tool 100 can expand the hole of the directional drilling hole 7 during drilling, and the fracturing sleeve 2 is pulled into the directional drilling hole 7.

[0087] In the embodiment of the application, by connecting the drilling tool 100 to the fracturing sleeve 2, the large-diameter fracturing sleeve 2 can be conveniently lowered into the deeper directional drilling hole 7, which is helpful to realize the hydraulic fracturing operation with large flow and high pressure, and can improve the fracturing effect and reduce the engineering quantity and engineering cost of the hydraulic fracturing construction.

[0088] S103, the fracturing sleeve 2 of other sections is connected at the rear end of the first section of the fracturing sleeve 2, until the first section of the fracturing sleeve 2 reaches the hole bottom of the directional drilling hole 7. When the first section of the fracturing sleeve 2 is continuously deepened into the directional drilling hole 7 with the drilling of the drilling tool 100, the other fracturing sleeves 2 are connected at the rear end of the first section of the fracturing sleeve 2, until the first section of the fracturing sleeve 2 reaches the hole bottom of the directional drilling hole 7. At this time, the lowering of the fracturing sleeve 2 is completed, and the multiple fracturing sleeves 2 are connected in sequence, thereby forming a hydraulic fracturing channel.

[0089] The two ends of the fracturing sleeve 2 have external thread sections and internal thread sections, namely the male thread 21 and the female thread 22, and 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.

[0090] S104, the torque shaft body 13 and the guide drill bit 14 of the drilling tool 100 are fished, so that the annular grouting channel 71 between the outer wall of the fracturing sleeve 2 and the inner wall of the directional drilling hole 7 is connected with the inner cavity of the fracturing sleeve 2.

[0091] 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 drilling tools 100 will produce powder residue during drilling, and when the fracturing casing 2 reaches the bottom of the directional borehole 7 with the drilling tool 100, the powder residue fills between the outer wall of the fracturing casing 2 and the inner wall of the directional borehole 7, affecting the subsequent pipe fixing operation, therefore, the annular grouting channel 71 between the outer wall of the fracturing casing 2 and the inner wall of the directional borehole 7 needs to be flushed, and after the powder residue is flushed, the subsequent cement slurry can be fully and uniformly filled in the annular grouting channel 71.

[0092] S106, grouting into the annular grouting channel 71, filling the annular grouting channel 71, to complete the pipe fixing of the fracturing casing 2. After the cement slurry filled in the annular grouting channel 71 is solidified, the fracturing casing 2 can be fixed in the directional borehole 7, to ensure the stability of the operation during hydraulic fracturing.

[0093] S107, cleaning the inner hole of the fracturing casing 2. During the grouting of the annular grouting channel 71, part of the cement slurry will enter the inner hole of the fracturing casing 2, therefore, the inner hole of the fracturing casing 2 needs to be cleaned, for example, a cleaning drill bit with a slightly smaller radial size than the fracturing casing 2 is arranged in the fracturing casing 2, and the cleaning drill bit is driven by the drilling machine and the drill pipe to clean the inner hole of the fracturing casing 2, to ensure the internal passage of the fracturing casing 2, and to 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 slag from the fracturing casing 2.

[0094] The downhole directional borehole 7 fracturing casing 2 full-length running method of the embodiment of the present application uses the fracturing casing 2 to replace the drill pipe, and during the reaming drilling of the directional borehole 7, the large-diameter fracturing casing 2 is run into the deeper directional borehole 7, to improve the operation efficiency, reduce the fracturing engineering cost and construction engineering quantity, and increase the flow area of the run-in fracturing casing 2, so that a large-flow and high-pressure water flow can be provided during the subsequent hydraulic fracturing, to improve the fracturing effect.

[0095] As shown in Figures 1-4 The drilling tool 100 of the embodiment of the present application includes a torque transmission casing 12, a reaming drill bit 11, a guide drill bit 14 and a torque transmission shaft body 13. The end of the torque transmission casing 12 close to the bottom of the directional borehole 7 is connected with the reaming drill bit 11, the end of the torque transmission casing 12 away from the bottom of the directional borehole 7 is connected with the fracturing casing 2, and the outer diameter size of the reaming drill bit 11 is larger than that of the fracturing casing 2, so that the directional borehole 7 can be reamed, and the fracturing casing 2 can be easily pulled into the directional borehole 7, and the annular grouting channel 71 between the inner wall of the directional borehole 7 and the outer wall of the fracturing casing 2 can be ensured.

[0096] The torque transmission shaft body 13 is used for connecting the torque transmission sleeve 12, and torque is transmitted between the two through the torque transmission member 131 and the key groove 121, that is, key transmission. During the drilling process of the fracturing sleeve 2 and the reamer bit 11, the torque transmission shaft body 13 can rotate synchronously, the pilot bit 14 is arranged at the end of the torque transmission shaft body 13 close to the hole bottom of the directional borehole 7, and the pilot bit 14 can also rotate synchronously with the reamer bit 11. The pilot bit 14 is closer to the hole bottom of the directional borehole 7 than the reamer bit 11, and the pilot bit 14 can play a guiding role to ensure that the drilling direction of the reamer bit 11 is the same as the extension direction of the pilot bit 14. The outer diameter size of the pilot bit 14 is smaller than the inner diameter size of the first through hole and the torque transmission sleeve 12, which facilitates subsequent fishing of the pilot bit 14.

[0097] Further, in order to avoid dust and slag entering the fracturing sleeve 2 during the drilling process, a sealing ring 132 is arranged between the torque transmission shaft body 13 and the inner wall of the first through hole to seal the end of the inner cavity of the fracturing sleeve 2.

[0098] In some embodiments, the torque transmission shaft body 13 and the pilot bit 14 of the fishing tool 100 include the following steps:

[0099] S201, connecting a fishing male cone 8 to one end of a drill rod. Since the annular grouting channel 71 needs to be unblocked between the annular grouting channel 71 and the inner hole of the fracturing sleeve 2 before flushing of the annular grouting channel 71, the flushing effect is improved, therefore, the torque transmission shaft body 13 and the pilot bit 14 are taken out of the fracturing sleeve 2 by using the drill rod and the fishing male cone 8.

[0100] S202, using a drilling machine to send the drill rod and the fishing male cone 8 to the hole bottom of the directional borehole 7 through the inner hole of the fracturing sleeve 2. The drill rod and the fishing male cone 8 are sent to the hole bottom of the directional borehole 7 by using the drilling machine, and the fishing male cone 8 is connected with the torque transmission shaft body 13.

[0101] S203, connecting the fishing male cone 8 with the second connecting part 133 of the torque transmission shaft body 13, driving the torque transmission shaft body 13 to rotate reversely, and taking out the torque transmission shaft body 13 and the pilot bit 14 through the drill rod and the fishing male cone 8.

[0102] Specifically, the end of the fishing male cone 8 is provided with a male cone, the end of the torque transmission shaft body 13 is provided with a female cone, and the male cone and the female cone are connected to form an integrated structure of the drill rod, the fishing male cone 8, the torque transmission shaft body 13 and the pilot bit 14. When the drill rod is rotated, the torque transmission member 131 of the torque transmission shaft body 13 enters the separation guide groove 122 from the key groove 121, the fishing male cone 8, the torque transmission shaft body 13 and the pilot bit 14 are taken out of the fracturing sleeve 2 by pulling the drill rod.

[0103] As Figure 6 , Figure 12 andFigure 13 As shown, in some embodiments, the hole sealing sleeve 5 is provided with a first flange plate 51 arranged at one end of the hole sealing sleeve 5 away from the directional drilling hole 7, and a flushing and grouting port 52 arranged on the side wall of the section of the hole sealing sleeve 5 located outside the directional drilling hole 7.

[0104] After the first section of the fracturing sleeve 2 reaches the hole bottom of the directional drilling hole 7, a second flange plate 6 is arranged at the end of the fracturing sleeve 2 located at the hole mouth of the directional drilling hole 7, and the first flange plate 51 and the second flange plate 6 are connected to form an annular grouting channel 71 between the fracturing sleeve 2 and the inner wall of the hole sealing sleeve 5 and between the fracturing sleeve 2 and the inner wall of the directional drilling hole 7.

[0105] It should be understood that, by arranging the second flange plate 6 at the end of the fracturing sleeve 2 located at the hole mouth of the directional drilling hole 7, the second flange plate 6 can be connected with the first flange plate 51, so as to form the annular grouting channel 71 between the fracturing sleeve 2 and the inner wall of the hole sealing sleeve 5 and between the fracturing sleeve 2 and the inner wall of the directional drilling hole 7, and the flushing and grouting port 52 is in communication with the annular grouting channel 71, so as to facilitate the flushing and grouting operation of the annular grouting channel 71 through the flushing and grouting port 52.

[0106] Optionally, the second flange plate 6 is welded and fixed on the fracturing sleeve 2, or the second flange plate 6 is provided with a connecting sleeve provided with a threaded section with a male thread or a female thread, and the second flange plate 6 is connected on the fracturing sleeve 2 through the threaded connection.

[0107] Optionally, a terminal sleeve can be arranged, the second flange plate 6 is arranged at one end of the terminal sleeve, and a threaded section with a male thread or a female thread is arranged at the other end of the terminal sleeve, after the first section of the fracturing sleeve 2 reaches the hole bottom of the directional drilling hole 7, the terminal sleeve is connected with the fracturing sleeve 2 located in the directional drilling hole 7, and then the second flange plate 6 is connected with the first flange plate 51.

[0108] In some embodiments, the length of the section of the hole sealing sleeve 5 located in the directional drilling hole 7 is 7m-14m. It should be understood that, when the length of the section of the hole sealing sleeve 5 located in the directional drilling hole 7 is less than 7m, the structural stability between the hole sealing sleeve 5 and the directional drilling hole 7 is not enough, which affects the structural stability of the hole sealing section, and when the length of the section of the hole sealing sleeve 5 located in the directional drilling hole 7 is greater than 14m, the construction length is too long, which makes the construction difficult. The length of the section of the hole sealing sleeve 5 located in the directional drilling hole 7 in the embodiments of the present application can be 7m, 7.5m, 8m, 9.3m, 10m, 11.6m, 13m or 14m.

[0109] As Figures 7-10As shown, in some embodiments, the step is performed in the connection of the other segments of the fracturing casing 2 after the rear end of the first segment of the fracturing casing 2, and the first casing 3 is connected after the partial fracturing casing 2, and the first casing 3 has protrusions 31 arranged in a spiral on the outer wall of the first casing 3.

[0110] It should be understood that the first casing 3 is a spiral guide, which specifically includes a first pipe body, the protrusions 31 arranged in a spiral are arranged on the outer wall of the first pipe body, the male thread 21 is arranged at one end of the first pipe body, and the female thread 22 is arranged at the other end of the first pipe body, and the protrusions 31 are fixed on the outer wall of the first pipe body by welding. By arranging the first casing 3 at intervals, the fracturing casing 2 can be guided, and at the same time in the rotation process of the first casing 3, the powder residue is pushed to move to the orifice by the protrusions 31 arranged in a spiral.

[0111] Further, the adjacent two fracturing casings 2 and the first casing 3 and the fracturing casings 2 located at the front end and the rear end of the first casing 3 are connected by threads.

[0112] Specifically, in the extension direction of the directional drilling hole 7, since the two ends of the fracturing casing 2 are respectively provided with the male thread 21 and the female thread 22, the adjacent two fracturing casings 2 connected with each other are connected by threads, when the first casing 3 is arranged between the two fracturing casings 2, the male thread 21 of the first casing 3 is connected with the female thread 22 of the fracturing casing 2 in front, and the female thread 22 of the first casing 3 is connected with the male thread 21 of the fracturing casing 2 at the rear, so that the first casing 3 can be arranged between the adjacent two fracturing casings 2, and the fracturing casing 2 can be connected while the first casing 3 can be used for auxiliary guiding of the fracturing casing 2.

[0113] Further, the extension trajectory of the protrusions 31 on the outer wall of the first casing 3 is a right-handed spiral, at this time, when the drilling machine drives the rotation of the fracturing casing 2 and the first casing 3, the right-handed spiral can be used to drive the powder residue in the directional drilling hole 7 to move to the orifice of the directional drilling hole 7, which facilitates the subsequent flushing operation of the annular grouting channel 71.

[0114] In some embodiments, the first casing 3 is multiple, the multiple first casings 3 are arranged at intervals in the extension direction of the directional drilling hole 7, and the interval between the previous first casing 3 and the next first casing 3 is 15-25 m. It should be noted that the present embodiment is used for the fracturing casing 2 to be lowered into work in a long drilling hole, and therefore multiple first casings 3 need to be arranged at intervals to guide the fracturing casing 2. Specifically, according to the requirements of the rotation and guidance of the fracturing casing 2 in the directional drilling hole 7, the interval distance between the adjacent two first casings 3 is set to 15-25 m. The interval distance between the adjacent two first casings 3 can be 15 m, 16 m, 18.5 m, 19.3 m, 21 m, 23.6 m, 24.7 m or 25 m. When the interval distance between the adjacent two first casings 3 is less than 15 m, the adjacent first casings 3 are too close, which does not have obvious improvement effect on the movement and guidance of the fracturing casing 2, and causes slow construction progress. The excessive use of the first casings 3 also leads to the increase of cost. When the interval distance between the adjacent two first casings 3 is greater than 25 m, the adjacent first casings 3 are too far apart, some of the fracturing casings 2 cannot be guided, which affects the subsequent flushing of the annular grouting channel 71 and the grouting hole-stabilizing operation of the fracturing casing 2.

[0115] As shown in Figures 7-10 some embodiments, the step is performed in the connection of the fracturing casings 2 in the first section of the fracturing casing 2. The second casing 4 is connected to the part of the fracturing casing 2. The outer wall of the second casing 4 is provided with a plurality of barbs 41. The barbs 41 extend from the outer wall of the second casing 4 to the inner wall of the directional drilling hole 7, and the barbs 41 are inclined towards the end of the second casing 4 away from the hole bottom of the directional drilling hole 7.

[0116] It should be understood that the second casing 4 is a hanging barb 41 casing, which specifically includes a second pipe body. A plurality of barbs 41 are arranged on the outer wall of the second pipe body in the circumferential direction. One end of the second pipe 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 pipe body in a trumpet-shaped open structure. In the process of drilling the fracturing casing 2 into the directional drilling hole 7, the barbs 41 can be closely fitted together with the hole wall of the directional drilling hole 7, and can be hooked on the hole wall, preventing the fracturing casing 2 from sliding down in the large-angle upward drilling hole, ensuring that the fracturing casing 2 can stably drill in, improving the lowering efficiency of the fracturing casing 2 in the directional drilling hole 7, and reducing the operation difficulty.

[0117] In some embodiments, the barbs 41 are elastic pieces that abut the inner wall of the directional borehole 7. It should be understood that the barbs 41 are elastic pieces that have a certain elasticity, and the elastic pieces abut the inner wall of the directional borehole 7. During the process of lowering the fracturing casing 2, the barbs 41 will be elastically deformed and will not affect the movement of the fracturing casing 2 to the bottom of the directional borehole 7. When in a large-angle uphole borehole, the fracturing casing 2 will move downward due to its own gravity. At this time, the barbs 41 can be hooked on the wall of the directional borehole 7, thereby preventing the fracturing casing 2 from sliding to the opening of the directional borehole 7, and ensuring the safety of the operation.

[0118] The number of barbs 41 on the second pipe body is at least 3, for example, the number of barbs 41 on the second pipe body is 3, 4, or 5, and the plurality of barbs 41 are uniformly distributed along the circumference of the second pipe body.

[0119] The downhole directional borehole 7 fracturing casing 2 full-length lowering method of the embodiment can be applied to directional boreholes 7 with a length of hundreds of meters or even thousands of meters, for example, can be applied to directional boreholes 7 with a depth of 500 m, 600 m, 750 m, 800 m, 930 m, 1100 m, or 1500 m. The depth of the directional borehole 7 can meet the range of hydraulic fracturing, thereby reducing the engineering quantity of coal mine hydraulic fracturing, improving the operation efficiency, providing high-pressure water with large flow, ensuring the fracturing effect, and reducing the engineering cost.

[0120] As shown in FIGS. Figure 15 and Figure 16 The following will take the uphole directional long borehole with a depth of 800 meters and an inclination angle of 35 degrees as an example to illustrate in detail the construction steps of the coal mine downhole directional borehole 7 large-flow fracturing casing 2 full-length lowering and grouting hole consolidation, mainly including the lowering of the hole sealing casing 5 at the borehole opening, the flushing of the borehole, the hole expansion of the bottom expansion tool 100, the connection and lowering of the fracturing casing 2, the connection of the rotary guide, the connection of the hanging barb 41 casing, the fishing of the directional drill bit 14, the cleaning of the annular grouting passage 71, the grouting of the casing 2 and the annular passage of the hole wall, and the cleaning of the inner hole of the fracturing casing 2.

[0121] Step 1: After the directional long borehole construction is completed, the hole sealing casing 5 is lowered at the borehole opening. The hole sealing casing 5 has a diameter of 168 mm and an inner hole of 154 mm. The hole sealing casing 5 outside the borehole opening is provided with a first flange plate 51 and a flushing and grouting port 52. The flushing and grouting port 52 is provided with a valve. The hole sealing casing 5 and the hole wall are integrated by injecting grouting cement between the outer wall of the hole sealing casing 5 and the hole wall.

[0122] Step 2: Drilling flushing is performed before the fracturing casing 2 is lowered. After drilling to the required depth using a drilling rig, a large amount of flushing water is introduced into the bottom of the borehole through the drill rod to thoroughly flush the borehole and ensure that there is not too much drill cuttings in the hole to obstruct the lowering of the fracturing casing 2.

[0123] Step 3: As Figure 15 As shown, after the sealing casing 5 is secured, the drill string 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 string 100 is sent into the sealing casing 5 using a drilling rig. After the drill string 100 is lowered into the hole, the drilling rig is used to rotate and drill, and subsequent fracturing casings 2 are lowered into the hole in sequence. During the rotational lowering of the fracturing casing 2, the guide drill bit 14 at the front end of the drill string 100 guides the drilling, and the reaming drill bit 11 enlarges the borehole wall to provide a channel for the lowering of the fracturing casing 2.

[0124] During the slewing and lowering of the fracturing casing 2, a rotary guide (first casing 3), also known as a helical 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 following fracturing casing 2. The rotary guide and the fracturing casing 2 are connected as a whole, making the fracturing casing 2 concentric with the borehole and providing sufficient cement slurry flow cavity for subsequent grouting and casing solidification.

[0125] During the slewing and lowering of the fracturing casing 2, a second casing 4, also known as the suspended barbed casing 41, is installed intermittently. The male thread 21 of the suspended barbed casing 41 connects to the female thread 22 of the preceding fracturing casing 2, and the female thread 22 of the suspended barbed casing 41 connects to the male thread 21 of the following fracturing casing 2. The suspended barbed casing 41 and the fracturing casing 2 are connected as a whole, with the barbs 41 engaging with the borehole wall to suspend the fracturing casing 2 within the borehole, preventing the fracturing casing 2 from slipping during the drilling process.

[0126] Step 4: After all the fracturing casings 2 are lowered into the directional borehole 7, the retrieval cone 8 is sent to the bottom of the hole using the drilling rig, so that the retrieval cone 8 is connected to the torque transmission shaft 13 in the drill bit 100 at the bottom of the hole, and the guide drill bit 14 at the front end of the drill bit 100 is retrieved, 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.

[0127] Step 5: After all the fracturing casings 2 have been lowered to the bottom of the hole, flushing water is injected into the bottom of the hole through the inner borehole of the fracturing casing 2 to clean the solidification channel (i.e., the annular grouting channel 71). A large amount of flushing water is injected into the bottom of the hole from the inner borehole of the fracturing casing 2, and then flows out from the annular cavity between the outer wall of the fracturing casing 2 and the borehole wall, thoroughly flushing the solidification channel to ensure that the subsequent grouting solidification channel is unobstructed.

[0128] Step 6: After the flushing of the pipe injection channel is completed, the fracturing casing 2 and the hole sealing casing 5 at the orifice are connected. The fracturing casing 2 at the orifice is configured with a second flange 6; the hole sealing casing 5 of the orifice is configured with a first flange 51 and a flushing injection port 52, and a valve is arranged at the flushing injection port 52. The fracturing casing 2 with the second flange 6 and the hole sealing casing 5 of the orifice are connected and fastened through the flanges, and the annular cavity between the outer wall of the fracturing casing 2 and the inner wall of the hole sealing casing 5, and the annular cavity between the outer wall of the fracturing casing 2 and the hole wall of the directional drilling hole 7 are communicated, forming a channel for pipe injection of cement slurry.

[0129] Step 7: As shown in Figure 16 , after the fracturing casing 2 and the hole sealing casing 5 are connected and fastened, the pipe injection of the cement slurry is performed from the flushing injection port 52 on the hole sealing casing 5 to the annular cavity between the fracturing casing 2 and the hole sealing casing 5, and the cement slurry is made to flow from the annular injection channel to the hole bottom by continuously injecting the cement slurry into the hole, until the cement slurry overflows from the inner hole of the fracturing casing 2, that is, the entire pipe injection annular cavity is filled with the cement slurry, and the injection pipe injection is completed.

[0130] Step 8: After the injection pipe injection is completed, the cement solid that overflows and solidifies in the inner hole of the fracturing casing 2 is cleaned by the drilling machine. The outer diameter of the cleaning bit used when the cement solid in the fracturing casing 2 is cleaned is smaller than the inner hole diameter of the fracturing casing 2. After cleaning, the fracturing casing 2 meets the requirements of large flow and high pressure hydraulic fracturing.

[0131] In the description of the present application, it should be understood that the orientations or positional relationships indicated by the terms “center”, “longitudinal”, “transverse”, “length”, “width”, “thickness”, “upper”, “lower”, “front”, “rear”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inner”, “outer”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential” are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0132] In addition, the terms “first” and “second” are only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with “first” and “second” can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of “a plurality of” is at least two, such as two, three, etc., unless otherwise specifically limited.

[0133] In the present application, unless specifically defined otherwise, the terms "mounting", "connected", "connecting", "fixed", "fixedly connected", "connection", "fixedly connected", "connected", "fixed", and the like should be construed broadly, for example, can be fixed connection, can be detachable connection, or integral; can be mechanical connection, can be electrical connection or communication with each other; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise specifically defined. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0134] In the present application, unless specifically defined otherwise, the first feature is "on" or "under" the second feature. The first and second features can be in direct contact, or the first and second features can be in indirect contact through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or only indicates that the first feature is higher than the second feature in horizontal height. The first feature "below", "under" and "under" the second feature can be that the first feature is directly below or obliquely below the second feature, or only indicates that the first feature is lower than the second feature in horizontal height.

[0135] In the present application, the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in the specification and the features of different embodiments or examples without contradiction.

[0136] Although the embodiments of the present application have been shown and described above, it is understood that the above embodiments are exemplary and cannot be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above embodiments within the scope of the present application.

Claims

1. A drilling tool, characterized in that, include: A reaming drill bit, wherein the reaming drill bit has a first through hole; A torque transmission sleeve is provided, which is coaxially arranged with the reaming drill bit and the reaming drill bit is connected to one end of the torque transmission sleeve. The other end of the torque transmission sleeve is provided with a first connecting part. The inner wall of the torque transmission sleeve is provided with a keyway and a separation guide groove, and the separation guide groove and the keyway are connected. A torque transmission shaft is provided, which is inserted into the first through hole and the torque transmission sleeve. The outer wall of the torque transmission shaft is provided with a torque transmission component, and one end of the torque transmission shaft is provided with a second connecting part. A guide drill bit is connected to the other end of the torque transmission shaft and is located in front of the reaming drill bit to guide the drilling direction of the reaming drill bit. The outer diameter of the guide drill bit is smaller than the inner diameter of the first through hole and the torque transmission sleeve. During the drilling operation of the reaming drill bit, the torque transmission element is located in the keyway and abuts against one side wall of the keyway to drive the torque transmission shaft to rotate synchronously with the torque transmission sleeve. When the reaming drill bit stops operating, the torque transmission shaft is rotated to allow the torque transmission element to enter the separation guide groove and separate from the torque transmission sleeve through the separation guide groove. The keyway has a first opening facing 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 separation guide groove are connected to form a Z-shaped groove. During assembly, the torque transmission component enters the keyway through the first opening. When the torque transmission sleeve rotates forward, one side wall of the keyway abuts against the torque transmission component, realizing the transmission of torque between the torque transmission sleeve and the torque transmission shaft. The other side wall of the keyway is connected to the separation guide groove through the third opening. When the torque transmission sleeve does not rotate, by rotating the torque transmission shaft, the torque transmission component enters the separation guide groove through the third opening. By pulling back the torque transmission shaft, the torque transmission component disengages from the Z-shaped groove through the second opening.

2. The drilling tool according to claim 1, characterized in that, The reaming drill bit is threadedly connected to the torque transmission sleeve, and one end of the reaming drill bit near the keyway abuts against the first opening of the keyway; and / or The torque transmission shaft is threadedly connected to the guide drill bit; 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 downhole directional drilling fracturing casing throughout its entire length, characterized in that, Includes the following steps: Construct directional drilling and clean the directional drilling, and fix a sealing sleeve at the opening section of the directional drilling; A drilling tool is connected to the front end of the first section of the fracturing casing near the bottom of the directional borehole. The drilling tool is as described in claim 1 or 2. The end of the fracturing casing equipped with the drilling tool is sent into the directional borehole. The fracturing casing and the drilling tool are driven to rotate and drill using a drilling rig, and the fracturing casing is pulled into the directional borehole. Other segments of the fracturing casing are then connected at the rear end of the fracturing casing described in the first section until the fracturing casing described in the first section reaches the bottom of the directional borehole. The torsion shaft and guide drill bit of the drilling tool are retrieved so that the annular grouting channel between the outer wall of the fracturing casing and the inner wall of the directional borehole is connected to the inner cavity of the fracturing casing. The annular grouting channel between the outer wall of the fracturing casing and the inner wall of the directional borehole is flushed. Grout is injected into the annular grouting channel to fill the annular grouting channel, thereby completing the solidification of the fracturing casing; Clean the inner bore of the fracturing casing.

4. The method for running downhole directional drilling fracturing casing throughout its entire length according to claim 3, characterized in that, The process of retrieving the torque transmission shaft and guide drill bit of the drilling tool includes the following steps: Connect a retrieval cone to one end of the drill pipe; The drill rod and the retrieval cone are fed to the bottom of the directional borehole through the inner hole of the fracturing casing using a drilling rig. The male retrieval cone is connected to the second connecting part of the torque transmission shaft, driving the torque transmission shaft to rotate in the opposite direction, and the torque transmission shaft and the guide drill bit are retrieved through the drill rod and the male retrieval cone.

5. The method for running downhole directional drilling fracturing casing throughout its entire length according to claim 3, characterized in that, The sealing sleeve has a first flange and a flushing and grouting port. The first flange is located at the end of the sealing sleeve away from the directional borehole, and the flushing and grouting port is located on the side wall of the section of the sealing sleeve located outside the directional borehole. After the fracturing casing described in Section 1 reaches the bottom of the directional borehole, 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 borehole. The first flange and the second flange are connected 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 borehole.

6. The method for running downhole directional drilling fracturing casing throughout its entire length according to claim 3 or 5, characterized in that, The length of the section of the sealing sleeve located in the directional borehole is 7m-14m.

7. The method for running downhole directional drilling fracturing casing throughout its entire length according to claim 3, characterized in that, In the process of connecting other segments of the fracturing casing at the rear end of the fracturing casing described in the first section, a first casing is connected after a portion of the fracturing casing, and the outer wall of the first casing has protrusions arranged in a spiral pattern.

8. The method for running downhole directional drilling fracturing casing throughout its entire length according to claim 7, characterized in that, The two adjacent fracturing casings, and the first casing and the fracturing casing located at the front and rear ends of the first casing, are all connected by threads; and / or The protrusion extends along a right-handed helix on the outer wall of the first sleeve; and / or There are multiple first casings, which are arranged at intervals in the extension direction of the directional borehole, and the distance between the previous first casing and the next first casing is 15m-25m.

9. The method for running downhole directional drilling fracturing casing throughout its entire length according to claim 3, characterized in that, In the process of connecting other segments of the fracturing casing at the rear end of the fracturing casing described in the first section, a second casing is connected after a portion of the fracturing casing. The outer wall of the second casing is provided with a plurality of barbs in the circumferential direction. The barbs extend from the outer wall of the second casing toward the inner wall of the directional borehole, and the barbs are inclined toward the end of the second casing away from the bottom of the directional borehole.

10. The method for running downhole directional drilling fracturing casing throughout its entire length according to claim 9, characterized in that, The barbs are elastic sheets; and / or The barbs abut against the inner wall of the directional borehole.

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