Horizontal directional drilling port blowout preventer and horizontal directional drilling assembly and disassembly method

Abstract

The application discloses a horizontal directional drilling orifice blowout preventer and a horizontal directional drilling tool combination assembling and disassembling method, and comprises an orifice pipe, a gate valve, a rubber flexible joint, a receiving sleeve, a primary pressing device, an extension sleeve and a secondary pressing device. The first end of the orifice pipe is connected to a foundation pit support. The first end of the orifice pipe is inserted into the vertical depth of the foundation pit support, which is greater than or equal to 250 mm and less than the thickness of the foundation pit support. The second end of the orifice pipe is sealingly and fixedly connected to the first end of the gate valve. The second end of the gate valve is sealingly and fixedly connected to the first end of the rubber flexible joint. The application adds a rubber flexible joint and a receiving sleeve, which can be bent and deformed at a certain angle and meet the mud pressure requirement and the sealing requirement. The original rigid orifice blowout preventer has a flexible deformation capacity and a longitudinal accommodation space is increased. The sealing property is ensured when a drill tool with a certain diameter difference passes.

Description

Technical Field

[0001] This invention relates to the field of blowout prevention technology in horizontal drilling. Specifically, it relates to a blowout prevention device for the orifice of a horizontally directional borehole and a method for assembling and disassembling horizontally directional drilling tools. Background Technology

[0002] In foundation pits or tunnels, horizontal freezing boreholes are prone to sand and water inrush during directional drilling in sandy, water-rich strata. To avoid this risk during horizontal drilling, a blowout preventer must be installed at the borehole opening before drilling. The blowout preventer ensures that no sand or water inrush occurs during horizontal drilling.

[0003] Typically, for downhole power drill bit directional drilling assemblies, the drill bit has the largest outer diameter, followed by the downhole power drill bit, and then the drill pipe. For directional drilling assemblies with a swivel-type directional drill bit, the directional drill bit has the largest outer size, the guide rod has a smaller outer diameter, and the drill pipe's outer diameter is less than or equal to the guide rod's outer diameter. In horizontal hole directional drilling, regardless of whether a swivel-type directional drill bit assembly or a downhole power drill bit directional drilling assembly is used, there is a diameter difference between the drill bit, the downhole power drill bit, and the drill pipe. There is also a diameter difference between the guide rod and the drill pipe in a swivel-type directional drill bit. Furthermore, both swivel-type directional drill bits and downhole power drill bit directional drilling assemblies have a bend. When these two types of assemblies are pulled out of the wellhead casing, existing wellhead blowout preventers cannot seal the wellhead in time, resulting in a significant risk of water and sand inrush. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is to provide a horizontal directional drilling orifice anti-blowout device that can promptly seal and prevent water and sand from gushing out when the horizontal directional drilling tool assembly enters and exits the orifice pipe, and a method for assembling and disassembling the horizontal directional drilling tool assembly.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a blowout prevention device for horizontal directional drilling, comprising an orifice pipe, a gate valve, a rubber flexible joint, a receiving sleeve, a primary clamping device, an extension sleeve, and a secondary clamping device. The first end of the orifice pipe is connected to the foundation pit retaining wall, and the vertical depth to which the first end of the orifice pipe is inserted into the foundation pit retaining wall is less than the thickness of the foundation pit retaining wall. The second end of the orifice pipe is sealed and fixedly connected to the first end of the gate valve. The second end of the gate valve is sealed and fixedly connected to the first end of the rubber flexible joint. The second end of the rubber flexible joint is sealed and fixedly connected to the first end of the receiving sleeve. The second end of the receiving sleeve is fixedly connected to the first end of the primary clamping device. The first end of the extension sleeve is sealed and fixedly connected to the second end of the primary clamping device. The second end of the extension sleeve is fixedly connected to the first end of the secondary clamping device.

[0006] In the above-mentioned horizontal directional drilling wellhead blowout preventer, the inner diameter of the wellhead pipe, the inner diameter of the gate valve, the inner diameter of the rubber flexible joint, and the inner diameter of the receiving sleeve are all greater than the maximum diameter of the horizontal directional drilling tool assembly; the working pressure of the rubber flexible joint is ≤1.6MPa, the inner diameter of the rubber flexible joint is greater than or equal to the outer diameter of the horizontal directional drilling tool assembly by 15mm, and the allowable deflection angle of the rubber flexible joint is greater than or equal to 10°.

[0007] The above-mentioned horizontal directional drilling wellhead blowout preventer has the following features: the wellhead pipe has a diameter of 150mm and a wall thickness of 5mm; the gate valve has a size of DN150mm; the receiving sleeve has a diameter of 150mm and a wall thickness of 5mm; the inner diameter of the secondary clamping device is 89mm; the maximum outer diameter of the drill bit in the horizontal directional drilling tool assembly is 133mm; and the drill rod has a diameter of 89mm.

[0008] When different horizontal directional drilling tool combinations are selected for the above-mentioned horizontal directional drilling orifice blowout preventer, the axial length of the receiving casing is greater than or equal to the length of the drive shaft of the downhole power drill in the horizontal directional drilling tool combination plus the length of the drill bit plus 200mm; the axial length of the receiving casing is greater than or equal to the length of the duck-foot type guide drill bit plus 200mm; and the axial length of the extension casing is greater than or equal to the length of the transition joint.

[0009] In the aforementioned horizontal directional drilling orifice blowout preventer, a flange is fixed to the second end of the orifice pipe, and the flange at the second end of the orifice pipe is fixedly connected to the first end of the gate valve by bolts. A sealing gasket is installed between the flange at the second end of the orifice pipe and the first end of the gate valve. Both ends of the receiving sleeve are fixedly connected to flanges. Both ends of the rubber flexible joint are formed with raised edges. A first compression ring and a second compression ring are fitted on the rubber flexible joint. The raised edge at the first end of the rubber flexible joint is located between the second compression ring and the second end of the gate valve. The second compression ring and the second end of the gate valve are fixedly connected by bolts. The raised edge at the second end of the rubber flexible joint is located between the first compression ring and the flange at the first end of the receiving sleeve. The first compression ring and the flange at the first end of the receiving sleeve are fixedly connected by bolts.

[0010] The aforementioned horizontal directional drilling orifice blowout preventer includes a primary clamping device comprising a rubber sleeve, a first outer sleeve, an inner sleeve, and a first adjusting bolt. Both ends of the rubber sleeve have protruding flanges. The inner sleeve is fitted onto the rubber sleeve, and the first outer sleeve is fitted onto the inner sleeve. A first adjusting flange is fixedly connected to the second end of the inner sleeve, and a second adjusting flange is fixedly connected to the first end of the first outer sleeve. The first adjusting flange and the second adjusting flange are connected by the first adjusting bolt. The protruding flange on the first end of the rubber sleeve is located between the second adjusting flange and the flange at the second end of the receiving sleeve. The second adjusting flange and the flange at the second end of the receiving sleeve are fixedly connected by bolts. Both ends of the extension sleeve are provided with flanges. The protruding flange on the second end of the rubber sleeve is located between the first adjusting flange and the flange at the first end of the extension sleeve. The first adjusting flange and the flange at the first end of the extension sleeve are fixedly connected by bolts.

[0011] The aforementioned horizontal directional drilling orifice blowout preventer, wherein the secondary clamping device includes a second outer sleeve, packing, a retaining ring, and a clamping plug. Flanges are provided at both ends of the second outer sleeve. The flange at the first end of the second outer sleeve and the flange at the second end of the extension sleeve are fixedly connected by bolts. The retaining ring is coaxially fixedly installed inside the first end of the second outer sleeve. The packing is disposed inside the second outer sleeve and fits against the retaining ring. The first end of the clamping plug is inserted into the second outer sleeve from the second end and clamps the packing. Flanges are fixedly connected to both the second end of the second outer sleeve and the second end of the clamping plug, and these flanges are fixedly connected by bolts.

[0012] The assembly and disassembly method for horizontal directional drilling tools includes the following steps:

[0013] Step A: Install the orifice pipe: Drill a horizontal hole in the foundation pit retaining wall with a hole depth ≥250mm and a hole depth less than the thickness of the foundation pit retaining wall. Insert the orifice pipe to the bottom of the horizontal hole and take measures to fix the orifice pipe.

[0014] Step B: Seal and fix the second end of the orifice pipe to the first end of the gate valve, seal and fix the second end of the gate valve to the first end of the rubber expansion joint, and seal and fix the second end of the rubber expansion joint to the first end of the receiving sleeve.

[0015] Step C: Lowering the horizontal directional drilling tool assembly: Insert the horizontal directional drilling tool assembly with drill bit into the second end of the receiving casing, then fix the second end of the receiving casing to the first end of the primary clamping device, install a transition joint on the second end of the horizontal directional drilling tool assembly, install the drill rod on the second end of the transition joint, and then clamp the primary clamping device to seal the horizontal borehole.

[0016] Step D: Start the mud pump and the horizontal drilling rig to advance forward and begin normal drilling until the horizontal directional drilling tool assembly penetrates the foundation pit retaining wall and enters the strata;

[0017] Step E: When drilling has reached halfway through the transition joint and entered the first-stage clamping device, stop drilling, stop the mud pump, and remove the drill pipe;

[0018] Step F: Fix the second end of the extension sleeve to the first end of the secondary clamping device, insert the drill rod through the second end of the secondary clamping device and connect it to the transition joint, seal and fix the first end of the extension sleeve to the second end of the primary clamping device, adjust the secondary clamping device to clamp the drill rod, and then loosen the primary clamping device.

[0019] Step G: Start the mud pump and the horizontal drilling rig, and begin normal or directional drilling operations until drilling is completed;

[0020] Step H: Stop the mud pump, pull out the drill pipe section by section, stop pulling out when the transition joint enters the extension casing, tighten the first-level clamping device, and loosen the second-level clamping device;

[0021] Step 1: Remove the secondary clamping device and extension sleeve, and remove the transition joint;

[0022] Step J: Under the sealed protection of the primary clamping device, pull out the horizontal directional drilling tool assembly. Stop pulling out when the drill bit of the horizontal directional drilling tool assembly enters the receiving casing.

[0023] Step K: Close the gate valve, pull out the horizontal directional drilling tool assembly with drill bit, and complete the entire drilling process.

[0024] In the above-mentioned method for assembling and disassembling a horizontal directional drilling assembly, the inner diameters of the orifice pipe, the gate valve, the rubber expansion joint, and the receiving sleeve are all greater than the maximum diameter of the horizontal directional drilling assembly; the working pressure of the rubber expansion joint is ≤1.6MPa, the inner diameter of the rubber expansion joint is greater than or equal to the outer diameter of the horizontal directional drilling assembly by 15mm, and the allowable deflection angle of the rubber expansion joint is greater than or equal to 10°; the diameter of the orifice pipe is 150mm and the wall thickness is 5mm; the size of the gate valve is DN150mm; the receiving sleeve... The diameter of the receiving casing is 150mm and the wall thickness is 5mm; the inner diameter of the two-stage clamping device is 89mm; the maximum outer diameter of the drill bit in the horizontal directional drilling assembly is 133mm; the diameter of the drill pipe is 89mm; the axial length of the receiving casing is greater than or equal to the length of the drive shaft of the downhole power drilling tool in the horizontal directional drilling assembly plus the length of the drill bit plus 200mm; the axial length of the receiving casing is greater than or equal to the length of the duck-foot directional drill bit plus 200mm; the axial length of the extension casing is greater than or equal to the length of the transition joint.

[0025] In the above-described method for assembling and disassembling horizontal directional drilling tools, a flange is fixed to the second end of the orifice pipe. The flange at the second end of the orifice pipe is fixedly connected to the first end of the gate valve by bolts. A sealing gasket is installed between the flange at the second end of the orifice pipe and the first end of the gate valve. Flanges are fixedly connected to both ends of the receiving sleeve. A raised edge is formed on both ends of the rubber flexible joint. A first compression ring and a second compression ring are fitted onto the rubber flexible joint. The raised edge on the first end of the rubber flexible joint is located between the second compression ring and the second end of the gate valve. The second compression ring and the second end of the gate valve are fixedly connected by bolts. A raised flange is located between the first clamping ring and the flange at the first end of the receiving sleeve. The first clamping ring and the flange at the first end of the receiving sleeve are fixedly connected by bolts. The primary clamping device includes a rubber sleeve, a first outer sleeve, an inner sleeve, and a first adjusting bolt. Raised flanges are formed on both ends of the rubber sleeve. The inner sleeve is fitted onto the rubber sleeve, and the first outer sleeve is fitted onto the inner sleeve. A first adjusting flange is fixedly connected to the second end of the inner sleeve, and a second adjusting flange is fixedly connected to the first end of the first outer sleeve. The first adjusting flange and the second adjusting flange are connected by the first adjusting bolt, which allows adjustment of the flange. The distance between the two flanges is designed to achieve both sealing and loosening states of the primary clamping device. The raised edge on the first end of the rubber sleeve is located between the second adjusting flange and the flange at the second end of the receiving sleeve. The second adjusting flange and the flange at the second end of the receiving sleeve are fixedly connected by bolts. Flanges are provided at both ends of the extension sleeve. The raised edge on the second end of the rubber sleeve is located between the first adjusting flange and the flange at the first end of the extension sleeve. The first adjusting flange and the flange at the first end of the extension sleeve are fixedly connected by bolts. The secondary clamping device includes a second outer sleeve, packing, a retaining ring, and a clamping plug. Flanges are provided at both ends of the second outer sleeve. The flange at the first end of the second outer sleeve and the flange at the second end of the extension sleeve are fixedly connected by bolts. The retaining ring is coaxially fixedly installed inside the first end of the second outer sleeve. The packing is disposed inside the second outer sleeve and fits against the retaining ring. The first end of the clamping plug is inserted into the second outer sleeve from the second end and clamps the packing. Flanges are fixedly connected to the second end of the second outer sleeve and the second end of the clamping plug. The flanges at the second end of the second outer sleeve and the flanges at the second end of the clamping plug are fixedly connected by bolts. By tightening or loosening the fixing bolts, the secondary clamping device can be sealed or the drill rod can be loosened.

[0026] The technical solution of the present invention achieves the following beneficial technical effects:

[0027] 1. Conventional wellhead blowout preventers (BOPs) consist entirely of steel components with rigid connections. This means the conventional wellhead device's axis is straight, while the horizontal directional drilling assembly itself has a bend of approximately 1.25°, forming a broken line. This causes localized deviations from the BOP's axis due to bending, resulting in some parts of the assembly being squeezed against the inner wall of the BOP and unable to pass freely. This invention addresses this by adding a rubber flexible joint and a receiving sleeve that can bend at a certain angle while meeting mud pressure and sealing requirements. This gives the original rigid wellhead BOP flexible deformation capabilities, increasing longitudinal and radial accommodating space. Together with other components, it can adaptively form a wellhead BOP with a certain degree of curvature, matching the curvature of the horizontal directional drilling assembly. This facilitates the smooth passage of the horizontal directional drilling assembly through the wellhead BOP and ensures sealing when drill bits with a certain diameter difference pass through. It can ensure that all components of a long horizontal directional drilling assembly (drill rod, directional drilling tool and drill bit) remain sealed when passing through the blowout preventer at the wellhead, thereby maintaining the mud pressure in the horizontal borehole at all times; and, during the process of lowering the horizontal directional drilling assembly into the horizontal borehole, or during the process of pulling the horizontal directional drilling assembly out of the horizontal borehole, it can always ensure that there is no risk of water jetting or sand inrush in the horizontal borehole.

[0028] 2. The present invention, by means of a receiving casing, can accommodate the lower half of the horizontal directional drilling tool assembly, so that the horizontal directional drilling tool assembly can be safely withdrawn from the borehole and kept in a sealed state, avoiding water spraying and sand inrush; by means of an extension casing, it can accommodate a transition joint, so that the sealing state of the primary clamping device and the secondary clamping device can be switched, thereby ensuring the sealing effect when loading and unloading the horizontal directional drilling tool assembly. Attached Figure Description

[0029] Figure 1 A schematic diagram of the overall structure of the present invention;

[0030] Figure 2 Schematic diagram of the structure of the rubber flexible joint connection of the present invention;

[0031] Figure 3 A schematic diagram of the structure of the extension sleeve of the present invention connected to the primary clamping device and the secondary clamping device.

[0032] The reference numerals in the figure are as follows: 1-orifice pipe; 2-gate valve; 3-rubber flexible joint; 4-receiving sleeve; 5-first-stage clamping device; 501-rubber sleeve; 502-first outer sleeve; 503-inner sleeve; 504-first adjusting flange; 505-second adjusting flange; 506-first adjusting bolt; 6-extension sleeve; 7-second-stage clamping device; 701-second outer sleeve; 702-packing; 703-retaining ring; 704-clamping plug; 8-excavation pit support; 9-formation; 10-horizontal directional drilling assembly; 11-transition joint; 12-drill pipe; 13-connecting pipe; 14-control valve; 15-safety valve; 16-sealing gasket ring; 17-first clamping ring; 18-second clamping ring. Detailed Implementation

[0033] Example 1

[0034] The blowout preventer at the orifice of the horizontal directional borehole in this embodiment is described in detail below. Figure 1 The system includes an orifice pipe 1, a gate valve 2, a rubber expansion joint 3, a receiving sleeve 4, a primary clamping device 5, an extension sleeve 6, and a secondary clamping device 7. The first end of the orifice pipe 1 is connected to the foundation pit retaining wall 8, and the depth of insertion of the first end of the orifice pipe 1 into the foundation pit retaining wall 8 is ≥250mm and less than the thickness of the foundation pit retaining wall 8. The second end of the orifice pipe 1 is sealed and fixedly connected to the first end of the gate valve 2, the second end of the gate valve 2 is sealed and fixedly connected to the first end of the rubber expansion joint 3, the second end of the rubber expansion joint 3 is sealed and fixedly connected to the first end of the receiving sleeve 4, the second end of the receiving sleeve 4 is fixedly connected to the first end of the primary clamping device 5, the first end of the extension sleeve 6 is sealed and fixedly connected to the second end of the primary clamping device 5, and the second end of the extension sleeve 6 is fixedly connected to the first end of the secondary clamping device 7. A connecting pipe 13 is connected to the orifice pipe 1 for fluid conduction, and a control valve 14 and a safety valve 15 are installed on the connecting pipe 13 to relieve pressure and prevent excessive mud pressure.

[0035] like Figure 2 As shown, the inner diameters of the orifice pipe 1, gate valve 2, rubber expansion joint 3, and receiving sleeve 4 are all larger than the maximum diameter of the horizontal directional drilling assembly 10; the diameter of the orifice pipe 1 is 150mm and the wall thickness is 5mm; the size of the gate valve 2 is DN150mm; the diameter of the receiving sleeve 4 is 150mm and the wall thickness is 5mm; the inner diameter of the secondary clamping device 7 is 89mm; the maximum outer diameter of the drill bit of the horizontal directional drilling assembly 10 is 133mm; and the diameter of the drill rod 12 is 89mm. By setting the orifice pipe 1, gate valve 2, rubber expansion joint 3, and receiving sleeve 4 with diameters larger than those of the directional drilling tool, the horizontal directional drilling assembly can pass through easily. The working pressure of the rubber expansion joint 3 is ≤1.6MPa, the difference between the inner diameter of the rubber expansion joint 3 and the diameter of the drill bit of the horizontal directional drilling assembly 10 is ≥15mm, and the allowable deflection angle of the rubber expansion joint 3 is greater than or equal to 10°.

[0036] The axial length of the receiving casing 4 is greater than or equal to the length of the drive shaft of the downhole power drill in the horizontal directional drilling assembly 10 plus the length of the drill bit plus 200mm; the axial length of the receiving casing 4 is greater than or equal to the length of the duck-foot guide drill bit plus 200mm; for example, the total length of the duck-foot guide rod and the drill bit is 1000mm, and the design length of the receiving casing is 1200mm; for example, the total length of the drive shaft and the drill bit of the down-bend shell downhole power drill is 1200mm, and the design length of the receiving casing is 1400mm. By setting the receiving casing 4, which is longer than the lower part of the horizontal directional drilling assembly 10, the drill can be smoothly and safely withdrawn from the orifice pipe 1.

[0037] like Figure 2 As shown, a flange is fixed to the second end of the orifice pipe 1. The flange on the second end of the orifice pipe 1 is fixedly connected to the first end of the gate valve 2 by bolts. A sealing gasket 16 is installed between the flange on the second end of the orifice pipe 1 and the first end of the gate valve 2. Both ends of the receiving sleeve 4 are fixedly connected to flanges. Both ends of the rubber flexible joint 3 are formed with raised edges. A first compression ring 17 and a second compression ring 18 are fitted on the rubber flexible joint 3. The raised edge on the first end of the rubber flexible joint 3 is located between the second compression ring 18 and the second end of the gate valve 2. The second compression ring 18 and the second end of the gate valve 2 are fixedly connected by bolts. The raised edge on the second end of the rubber flexible joint 3 is located between the first compression ring 17 and the flange at the first end of the receiving sleeve 4. The first compression ring 17 and the flange at the first end of the receiving sleeve 4 are fixedly connected by bolts.

[0038] like Figure 3 As shown, the primary clamping device 5 includes a rubber sleeve 501, a first outer sleeve 502, an inner sleeve 503, and a first adjusting bolt 506. Both ends of the rubber sleeve 501 are formed with raised edges. The inner sleeve 503 is fitted onto the rubber sleeve 501, and the first outer sleeve 502 is fitted onto the inner sleeve 503. A first adjusting flange 504 is fixedly connected to the second end of the inner sleeve 503, and a second adjusting flange 505 is fixedly connected to the first end of the first outer sleeve 502. The first adjusting flange 504 and the second adjusting flange 506... 5. The rubber sleeve 501 is connected by the first adjusting bolt 506. The protruding edge on the first end of the rubber sleeve 501 is located between the second adjusting flange 505 and the flange at the second end of the receiving sleeve 4. The second adjusting flange 505 and the flange at the second end of the receiving sleeve 4 are fixedly connected by bolts. Both ends of the extension sleeve 6 are provided with flanges. The protruding edge on the second end of the rubber sleeve 501 is located between the first adjusting flange 504 and the flange at the first end of the extension sleeve 6. The first adjusting flange 504 and the flange at the first end of the extension sleeve 6 are fixedly connected by bolts.

[0039] The secondary clamping device 7 includes a second outer sleeve 701, packing 702, a retaining ring 703, and a clamping plug 704. Flanges are provided at both ends of the second outer sleeve 701. The flange at the first end of the second outer sleeve 701 and the flange at the second end of the extension sleeve 6 are fixedly connected by bolts. The retaining ring 703 is coaxially fixedly installed inside the first end of the second outer sleeve 701. The packing 702 is disposed inside the second outer sleeve 701 and fits against the retaining ring 703. The first end of the clamping plug 704 is inserted into the second outer sleeve 701 from the second end and clamps the packing 702. Flanges are fixedly connected to the second end of both the second outer sleeve 701 and the second end of the clamping plug 704. The flanges at the second end of the second outer sleeve 701 and the second end of the clamping plug 704 are fixedly connected by bolts. By setting up the primary clamping device 5 and the secondary clamping device 7, the horizontal directional drilling tool assembly 10 or the drill pipe 12 can be alternately sealed, ensuring that no sand or water inrush occurs when loading or unloading the drilling tool.

[0040] Example 2

[0041] The method for assembling and disassembling horizontal directional drilling tools in this embodiment includes the following steps:

[0042] Step A: Install the orifice pipe 1: Drill a horizontal hole in the foundation pit retaining wall 8 with a hole depth ≥ 250 mm and a hole depth less than the thickness of the foundation pit retaining wall 8. Insert the orifice pipe 1 to the bottom of the horizontal hole and take measures to fix the orifice pipe 1.

[0043] Step B: Seal and fix the second end of the orifice pipe 1 to the first end of the gate valve 2, seal and fix the second end of the gate valve 2 to the first end of the rubber flexible joint 3, and seal and fix the second end of the rubber flexible joint 3 to the first end of the receiving sleeve 4.

[0044] Step C: Lowering the Horizontal Directional Drilling Tool Assembly 10: Insert the horizontal directional drilling tool assembly 10 with drill bit from the second end of the receiving casing 4, then fix the second end of the receiving casing 4 to the first end of the primary clamping device 5. Install the transition joint 11 on the second end of the horizontal directional drilling tool assembly 10, install the drill rod 12 on the second end of the transition joint 11, and then clamp the primary clamping device 5 to seal the horizontal borehole; when clamping the primary clamping device 5, if... Figure 3 As shown, by turning the first adjusting bolt 506, the first adjusting bolt 506 drives the first adjusting flange 504 and the second adjusting flange 505 to move closer to each other, thereby squeezing the rubber sleeve 501 to deform it and make it completely fit on the horizontal directional drilling tool assembly 10.

[0045] Step D: Start the mud pump and start the horizontal drilling rig to advance forward and begin normal drilling until the horizontal directional drilling tool assembly 10 penetrates the foundation pit retaining wall 8 and enters the stratum 9; when Step D is completed, the horizontal directional drilling tool assembly 10 has drilled into the stratum, and at this time it is necessary to continue to increase the drilling depth. The end of the horizontal directional drilling tool assembly is a transition joint.

[0046] Step E: When drilling reaches halfway into the first-stage clamping device 5 at the transition joint 11, stop drilling, stop the mud pump, remove the drill rod 12, stop the pump, and prepare to extend the cutting length.

[0047] Step F: Fix the second end of the extension sleeve 6 to the first end of the secondary clamping device 7, insert the drill rod 12 through the second end of the secondary clamping device 7 and connect it to the transition joint 11, seal and fix the first end of the extension sleeve 6 to the second end of the primary clamping device 5, adjust the secondary clamping device 7 to clamp the drill rod 12, and then loosen the primary clamping device 5; when adjusting the secondary clamping device 7, if... Figure 3 As shown, the bolts used to tighten the second outer sleeve 701 and the clamping plug 704 cause the clamping plug 704 to press inward against the packing 702, making the packing 702 seal tightly against the drill pipe 12; after the extension, the extended wellhead blowout preventer is connected, namely the extension sleeve 6 and the secondary clamping device 7. There is a diameter difference between the outer diameter of the extended drill pipe and the outer diameter of the horizontal directional drilling tool assembly 10, with the drill pipe having a smaller outer diameter. The primary clamping device 5 seals the horizontal directional drilling tool assembly 10. After the horizontal directional drilling tool assembly 10 drills into the formation, that is, after part of the horizontal directional drilling tool assembly 10 has passed through the primary clamping device 5, the primary clamping device 5 can be loosened; the secondary clamping device 7 seals the drill pipe. After the horizontal directional drilling tool assembly 10 is connected to the transition joint 11, each extension is the drill pipe. At this time, the secondary clamping device 7 is used for sealing and blowout prevention.

[0048] Step G: Start the mud pump and the horizontal drilling rig, and begin normal or directional drilling operations until drilling is completed;

[0049] Step H: Stop the mud pump, pull out the drill pipe 12 section by section, stop pulling out when the transition joint 11 enters the extension casing 6, tighten the first-level clamping device 5, and loosen the second-level clamping device 7.

[0050] Step I: Remove the secondary clamping device 7 and the extension sleeve 6, and remove the transition joint 11;

[0051] Step J: Under the sealed protection of the first-level clamping device 5, pull out the horizontal directional drilling tool assembly 10. Stop pulling out when the drill bit of the horizontal directional drilling tool assembly 10 enters the receiving casing 4.

[0052] Step K: Close gate valve 2, pull out the horizontal directional drilling tool assembly 10 with drill bit, and complete the entire drilling process.

[0053] The inner diameters of the orifice pipe 1, gate valve 2, rubber expansion joint 3, and receiving sleeve 4 are all larger than the maximum diameter of the horizontal directional drilling assembly 10; the working pressure of the rubber expansion joint 3 is ≤1.6MPa, the inner diameter of the rubber expansion joint 3 is greater than or equal to the outer diameter of the horizontal directional drilling assembly 10 (15mm), and the allowable deflection angle of the rubber expansion joint 3 is greater than or equal to 10°; the diameter of the orifice pipe 1 is 150mm and the wall thickness is 5mm; the size of the gate valve 2 is DN150mm; the diameter of the receiving sleeve 4 is 15mm. 0mm, wall thickness is 5mm; the inner diameter of the secondary clamping device 7 is 89mm; the maximum outer diameter of the drill bit of the horizontal directional drilling tool assembly 10 is 133mm; the diameter of the drill pipe 12 is 89mm; the axial length of the receiving casing 4 is greater than or equal to the length of the drive shaft of the downhole power drilling tool in the horizontal directional drilling tool assembly 10 plus the length of the drill bit plus 200mm; the axial length of the receiving casing 4 is greater than or equal to the length of the duck-foot type directional drill bit plus 200mm; the axial length of the extension casing 6 is greater than or equal to the length of the transition joint 11.

[0054] A flange is fixed to the second end of the orifice pipe 1. The flange at the second end of the orifice pipe 1 is fixedly connected to the first end of the gate valve 2 by bolts. A sealing gasket 16 is installed between the flange at the second end of the orifice pipe 1 and the first end of the gate valve 2. Both ends of the receiving sleeve 4 are fixedly connected to flanges. Both ends of the rubber expansion joint 3 are formed with raised edges. A first compression ring 17 and a second compression ring 18 are fitted on the rubber expansion joint 3. The raised edge at the first end of the rubber expansion joint 3 is located between the second compression ring 18 and the second end of the gate valve 2. The second compression ring 18 and the second end of the gate valve 2 are fixedly connected by bolts. The raised edge at the second end of the rubber expansion joint 3 is located between the first compression ring. The first clamping ring 17 and the flange at the first end of the receiving sleeve 4 are fixedly connected by bolts; the first-stage clamping device 5 includes a rubber sleeve 501, a first outer sleeve 502, an inner sleeve 503, and a first adjusting bolt 506. Both ends of the rubber sleeve 501 are formed with raised edges. The inner sleeve 503 is fitted onto the rubber sleeve 501, and the first outer sleeve 502 is fitted onto the inner sleeve 503. A first adjusting flange 504 is fixedly connected to the second end of the inner sleeve 503, and a second adjusting flange 505 is fixedly connected to the first end of the first outer sleeve 502. The first adjusting flange 504 and the second adjusting flange 505 communicate with each other. The rubber sleeve 501 is connected via the first adjusting bolt 506. The flange on the first end of the rubber sleeve 501 is located between the flange on the second adjusting flange 505 and the flange on the second end of the receiving sleeve 4. The second adjusting flange 505 and the flange on the second end of the receiving sleeve 4 are fixedly connected by bolts. Both ends of the extension sleeve 6 are provided with flanges. The flange on the second end of the rubber sleeve 501 is located between the flange on the first adjusting flange 504 and the flange on the first end of the extension sleeve 6. The first adjusting flange 504 and the flange on the first end of the extension sleeve 6 are fixedly connected by bolts. The secondary clamping device 7 includes a second outer sleeve 701, packing 702, a retaining ring 703, and a clamping plug 704. The second outer sleeve 701... Flanges are provided at both ends. The flange at the first end of the second outer sleeve 701 and the flange at the second end of the extension sleeve 6 are fixedly connected by bolts. The retaining ring 703 is coaxially fixedly installed inside the first end of the second outer sleeve 701. The packing 702 is set inside the second outer sleeve 701 and fits against the retaining ring 703. The first end of the compression plug 704 is inserted into the second outer sleeve 701 from the second end of the second outer sleeve 701 and compresses the packing 702. Flanges are fixedly connected to the second end of the second outer sleeve 701 and the second end of the compression plug 704. The flanges at the second end of the second outer sleeve 701 and the flanges at the second end of the compression plug 704 are fixedly connected by bolts.

[0055] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of the claims of this patent application.

Claims

1. A blowout preventer for horizontally oriented boreholes, characterized in that, The device includes an orifice pipe (1), a gate valve (2), a rubber flexible joint (3), a receiving sleeve (4), a primary clamping device (5), an extension sleeve (6), and a secondary clamping device (7). The first end of the orifice pipe (1) is connected to the pit retaining wall (8). The vertical depth of the first end of the orifice pipe (1) inserted into the pit retaining wall (8) is less than the thickness of the pit retaining wall (8). The second end of the orifice pipe (1) is sealed and fixedly connected to the first end of the gate valve (2). The second end of the gate valve (2) is sealed and fixedly connected to the first end of the rubber flexible joint (3). The second end of the rubber flexible joint (3) is sealed and fixedly connected to the first end of the receiving sleeve (4). The second end of the receiving sleeve (4) is fixedly connected to the first end of the primary clamping device (5). The first end of the extension sleeve (6) is sealed and fixedly connected to the second end of the primary clamping device (5). The second end of the extension sleeve (6) is fixedly connected to the first end of the secondary clamping device (7). The inner diameter of the orifice pipe (1), the inner diameter of the gate valve (2), the inner diameter of the rubber flexible joint (3), and the inner diameter of the receiving sleeve (4) are all greater than the maximum diameter of the horizontal directional drilling tool assembly (10); the working pressure of the rubber flexible joint (3) is ≤1.6MPa, the difference between the inner diameter of the rubber flexible joint (3) and the drill bit diameter of the horizontal directional drilling tool assembly (10) is ≥15mm, and the allowable deflection angle of the rubber flexible joint (3) is greater than or equal to 10°; The diameter of the orifice pipe (1) is 150 mm and the wall thickness is 5 mm; the size of the gate valve (2) is DN150 mm; the diameter of the receiving sleeve (4) is 150 mm and the wall thickness is 5 mm; the inner diameter of the secondary clamping device (7) is 89 mm; the maximum outer diameter of the drill bit of the horizontal directional drilling tool assembly (10) is 133 mm; the diameter of the drill rod (12) is 89 mm. The axial length of the receiving casing (4) is greater than or equal to the length of the drive shaft of the downhole power drill in the horizontal directional drilling assembly (10) plus the length of the drill bit plus 200mm; the axial length of the receiving casing (4) is greater than or equal to the length of the duck-foot type guide drill bit plus 200mm; the axial length of the extension casing (6) is greater than or equal to the length of the transition joint (11). A flange is fixed to the second end of the orifice pipe (1). The flange on the second end of the orifice pipe (1) is fixedly connected to the first end of the gate valve (2) by bolts. A sealing gasket (16) is installed between the flange on the second end of the orifice pipe (1) and the first end of the gate valve (2). Both ends of the receiving sleeve (4) are fixedly connected to flanges. Both ends of the rubber flexible joint (3) are formed with protrusions. A first compression ring (17) and a second compression ring (18) are fitted on the rubber flexible joint (3). The protrusion on the first end of the rubber flexible joint (3) is located between the second compression ring (18) and the second end of the gate valve (2). The second compression ring (18) and the second end of the gate valve (2) are fixedly connected by bolts. The protrusion on the second end of the rubber flexible joint (3) is located between the first compression ring (17) and the flange at the first end of the receiving sleeve (4). The first compression ring (17) and the flange at the first end of the receiving sleeve (4) are fixedly connected by bolts. Insert the first end of the horizontal directional drilling tool assembly (10) with the drill bit into the second end of the receiving casing (4), then fix the second end of the receiving casing (4) to the first end of the primary clamping device (5), install the transition joint (11) on the second end of the horizontal directional drilling tool assembly (10), install the drill rod (12) on the second end of the transition joint (11), and then clamp the primary clamping device (5) to seal the horizontal borehole.

2. The blowout preventer for horizontal directional drilling orifices according to claim 1, characterized in that, The primary clamping device (5) includes a rubber sleeve (501), a first outer sleeve (502), an inner sleeve (503), and a first adjusting bolt (506). Both ends of the rubber sleeve (501) are formed with raised edges. The inner sleeve (503) is fitted onto the rubber sleeve (501), and the first outer sleeve (502) is fitted onto the inner sleeve (503). A first adjusting flange (504) is fixedly connected to the second end of the inner sleeve (503), and a second adjusting flange (505) is fixedly connected to the first end of the first outer sleeve (502). The first adjusting flange (504) and the second adjusting flange (506) are connected together. 5) The rubber sleeve (501) is connected by the first adjusting bolt (506). The protrusion on the first end of the rubber sleeve (501) is located between the second adjusting flange (505) and the flange at the second end of the receiving sleeve (4). The second adjusting flange (505) and the flange at the second end of the receiving sleeve (4) are fixedly connected by bolts. Both ends of the extension sleeve (6) are provided with flanges. The protrusion on the second end of the rubber sleeve (501) is located between the first adjusting flange (504) and the flange at the first end of the extension sleeve (6). The first adjusting flange (504) and the flange at the first end of the extension sleeve (6) are fixedly connected by bolts.

3. The blowout preventer for horizontal directional drilling orifices according to claim 2, characterized in that, The secondary clamping device (7) includes a second outer sleeve (701), packing (702), a retaining ring (703), and a clamping plug (704). Flanges are provided at both ends of the second outer sleeve (701). The flange at the first end of the second outer sleeve (701) and the flange at the second end of the extension sleeve (6) are fixedly connected by bolts. The retaining ring (703) is coaxially fixedly installed inside the first end of the second outer sleeve (701). The packing (702) is disposed inside the second outer sleeve (701) and fits against the retaining ring (703). The first end of the clamping plug (704) is inserted into the second outer sleeve (701) from the second end of the second outer sleeve (701) and clamps the packing (702). Flanges are fixedly connected to the second end of the second outer sleeve (701) and the second end of the clamping plug (704). The flange at the second end of the second outer sleeve (701) and the flange at the second end of the clamping plug (704) are fixedly connected by bolts.

4. A method for assembling and disassembling horizontal directional drilling tools, characterized in that, The method of using the blowout preventer for horizontal directional boreholes according to any one of claims 1-3 includes the following steps: Step A: Install the orifice pipe (1): Drill a horizontal hole on the foundation pit retaining wall (8) with a hole depth ≥250mm and a hole depth less than the thickness of the foundation pit retaining wall (8). Insert the orifice pipe (1) to the bottom of the horizontal hole and take measures to fix the orifice pipe (1). Step B: Seal and fix the second end of the orifice pipe (1) to the first end of the gate valve (2), seal and fix the second end of the gate valve (2) to the first end of the rubber flexible joint (3), and seal and fix the second end of the rubber flexible joint (3) to the first end of the receiving sleeve (4). Step C: Lowering the horizontal directional drilling assembly (10): Insert the horizontal directional drilling assembly (10) with drill bit into the second end of the receiving casing (4), then fix the second end of the receiving casing (4) to the first end of the first-stage clamping device (5), install the transition joint (11) on the second end of the horizontal directional drilling assembly (10), install the drill rod (12) on the second end of the transition joint (11), and then clamp the first-stage clamping device (5) to seal the horizontal borehole; Step D: Start the mud pump and start the horizontal drilling rig to advance forward and begin normal drilling until the horizontal directional drilling tool assembly (10) penetrates the foundation pit retaining wall (8) and enters the stratum (9); Step E: When drilling has progressed to half of the transition joint (11) and entered the first-stage clamping device (5), stop drilling, stop the mud pump, and remove the drill rod (12). Step F: Fix the second end of the extension sleeve (6) to the first end of the secondary clamping device (7), insert the drill rod (12) through the second end of the secondary clamping device (7) and connect it to the transition joint (11), seal and fix the first end of the extension sleeve (6) to the second end of the primary clamping device (5), adjust the secondary clamping device (7) to clamp the drill rod (12), and then loosen the primary clamping device (5). Step G: Start the mud pump and the horizontal drilling rig, and begin normal or directional drilling operations until drilling is completed; Step H: Stop the mud pump, pull out the drill rod (12) section by section, stop pulling out when the transition joint (11) enters the extension casing (6), tighten the first-level clamping device (5), and loosen the second-level clamping device (7). Step 1: Remove the secondary clamping device (7) and the extension sleeve (6), and remove the transition joint (11); Step J: Under the sealed protection of the first-level clamping device (5), pull out the horizontal directional drilling tool assembly (10), and stop pulling out when the drill bit of the horizontal directional drilling tool assembly (10) enters the receiving casing (4); Step K: Close the gate valve (2), pull out the horizontal directional drilling tool assembly (10) with drill bit, and complete the entire drilling process.

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