Deep-buried fractured stratum ground long-distance directional drilling three-opening casing pipe slotting grouting method

Abstract

The invention discloses a deeply-buried fractured stratum ground long-distance directional drilling three-opening casing pipe slotting grouting method which comprises the following steps: S1, performing three-opening segmented hole forming on a horizontal section, and performing hole forming grouting; and S2, a third-section casing pipe is put down from the second-section casing pipe, the joint of the second-section casing pipe and the third-section casing pipe is sealed, and then well cementation is conducted on the third-section casing pipe. According to the method, the third-section casing pipe is put down after third-section hole-forming grouting, and a retreating type sectional slotting grouting mode is adopted, so that the problems that hole sweeping is repeated, new holes are formed, a drill is stuck, pressure is attenuated when a horizontal grouting section is long, and the actual grouting pressure cannot be accurately determined in horizontal section open hole grouting can be effectively solved, and meanwhile the problem that when floral tube grouting and high-pressure grouting are conducted, the grouting efficiency is greatly improved is solved. The problems that grouting holes are broken down, grout flows around, drill rods are fixed, well holes are scrapped and the like are solved, and meanwhile the mode of retreating type segmented slotting grouting is adopted, so that the grouting pressure can be increased to the maximum extent, high-pressure grouting is conducted, the stratum is split, and the grouting effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel grouting, in particular to a three-opening casing slot grouting method for long-distance directional drilling on the ground of a deep-buried broken stratum. Background Art

[0002] Directional wells (also known as directional drilling) are wells drilled according to a pre-designed well inclination and borehole axis shape. Ground-based long-distance directional horizontal drilling technology was initially used in the coal mining industry for deep stratum grouting, water blocking and reinforcement of complex underground strata, regional water hazard prevention, and goaf management. Currently, it is gradually being applied to the water conservancy industry for pre-excavation treatment of adverse geological conditions in deep buried tunnels, emergency rescue of tunnel leakage, and geological and hydrological exploration. Compared with traditional reinforcement, it has the advantages of safe construction, less interference in construction work, shorter construction period and higher efficiency.

[0003] Currently, tunnel construction for highway, railway, and water conservancy projects in southwest my country, particularly in the Yunnan-Tibet region, is being impacted by orogenic compression and steep strata dips. This creates complex and unfavorable geological conditions, characterized by fragmented strata, significant lithologic variations, wide fault zones, and structural rocks primarily composed of cataclastic rock, crushed pulverized rock, and breccia. The rock mass is fragmented, with localized mudification. In some areas, water flows through upper karst fissures, leading to risks such as mud and water inrush, deformation, and collapse of the surrounding rock during tunnel excavation. To address these geological challenges, an "L"-type ground pre-grouting method is being used to preemptively grout and reinforce the surrounding rock in the fault zone, mitigating risks and improving tunnel construction efficiency. The "L"-type ground pre-grouting method essentially utilizes a three-section wellbore design: the first section is the vertical section (casing run), the second section is the inclined section (casing run), and the third section is the horizontal grouting section. However, the grouting methods used for these three horizontal grouting sections vary widely, resulting in significant variations in grouting effectiveness and construction risks. Currently, the following methods are primarily used for grouting the horizontal sections: (1) Horizontal open hole grouting method: forward segmented grouting is used. Due to the large length of the open hole section, as the horizontal grouting length increases, the grouting pressure decreases and increases with the length of the horizontal section, making it impossible to accurately determine the actual grouting pressure of the grouting section. The wall of the open hole is irregular, and the grouting is likely to accumulate at a certain position in the open hole. At the same time, the hole wall is unstable in poor geological bodies. Under the action of high pressure, the hole wall is prone to collapse, resulting in low construction efficiency. At the same time, there are repeated hole sweeping, which is prone to new holes and drill stuck.

[0004] (2) Horizontal section flower pipe grouting: To compensate for the pressure attenuation of horizontal section bare hole grouting and the problems of drill hole and drill sticking caused by repeated hole sweeping, a three-opening horizontal section flower pipe grouting method was designed. This method has the problem that the grouting hole sealing material used in the flower pipe can penetrate the grouting hole from the outside under high pressure grouting, causing cement slurry to flow around, making it impossible to pull out the drill pipe and risking the wellbore being scrapped. The relevant technology is not mature enough. Summary of the Invention

[0005] The purpose of the present invention is to solve the above-mentioned shortcomings and provide a method for long-distance directional drilling casing slit grouting suitable for deep-buried tunnels (holes) with extremely broken water-rich surrounding rock. This method is to lower the three-opening casing into the ground after the three-opening grouting, and after the casing is fixed with shell material, adopt the backward segmented slit grouting method to eradicate the problems of repeated sweeping of new holes in open hole grouting, drill sticking, and grouting with flower pipes, which may cause the grouting hole to be penetrated under high external pressure, mud bypass, drill pipe fixation, and wellbore scrapping.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solution: a three-opening casing slot grouting method for long-distance directional drilling in deep-buried broken strata, wherein the long-distance directional grouting hole on the ground is an L-shaped structure, and the wellbore structure is designed with three openings, wherein the first opening is a vertical section, the second opening is a deflection section, and the third opening is a horizontal grouting section, including the following steps: S1: Drill holes in three sections of the horizontal section and perform grouting; S2. Lowering the tertiary casing from the secondary casing, sealing the connection between the secondary and tertiary casings, and then cementing the tertiary casing; S3, connecting the drill pipe to the upper joint of the cutter, and moving the cutter to the position to be cut at the bottom of the three-way casing through the drill pipe, thereby dividing the three-way casing into multiple sections; S4, start the pump circulation, use the cutter to cut the three-way casing, after the previous cutting operation is completed, the cutter position is moved back according to the cutting spacing, and the cutting operation is continued until the cutting of the casing section is completed and the drilling is started; S5. After the drilling is completed, the ground hole is grouting. The slurry enters the formation through the second opening casing, the third opening casing and the cut slit. When the grouting standard is reached, the grouting is completed. S6. Repeat steps S4-S5 to complete the slitting of the three-section casing, and complete the grouting of each slit after each section of the casing is slit.

[0007] Furthermore, the S4 step specifically includes the following steps: S41, start the pump circulation, push the piston shaft forward, make the cutter head open outward, and rotate by opening the drill pipe to cut the position to be cut on the three-open casing; S42. After cutting for 5-10 minutes, observe the change of torque. When the torque decreases or the turntable chain jumps, and the sensitive needle flashes, it means that the three-way casing is cut off; S43, turn off the pump, the spring pulls the piston shaft back, the cutter head resets, and the cutting is completed at this position; S44, the position of the cutter is moved back according to the slit spacing, moved to the rear position to be slit, and the slit is continued until the slit of the section of casing is completed and then the drill is started.

[0008] Furthermore, in step S4, the length of each casing section is 30-60 m, and the slit spacing is 1-2 m.

[0009] Furthermore, the length of the slit is 1 / 3-2 / 3 of the circumference of the cross section of the three-open casing, and the slit width is 1 cm.

[0010] Furthermore, in the step S2, a liner hanger is used to seal the double-open casing and the triple-open casing.

[0011] Furthermore, the double-open casing and the triple-open casing overlap by 10-20m.

[0012] Furthermore, in the step S2, the specific method of cementing is to fill the annular space of the three-opening casing with clay cement slurry.

[0013] Furthermore, the clay cement slurry has a density ranging from 1.18 to 1.2×10 3 kg / m 3 Clay slurry, 350-500 kg / m 3 of cement and 5 L / m 3 water glass.

[0014] Furthermore, during the process of feeding the drill rod in S3 and the process of pulling out the drill in S4, the pump is in a closed state.

[0015] Furthermore, during the S42 cutting process, the pump pressure and displacement should be uniform and stable, and smooth operation should be performed to avoid damage to the cutter head.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention inserts a three-opening casing after three-opening grouting and adopts a backward segmented slot grouting method, which can effectively avoid the problems of repeated hole sweeping, new hole production, drill jamming, pressure attenuation when the horizontal grouting section is long, and the inability to accurately determine the actual grouting pressure. At the same time, it solves the problems of grouting holes being punctured, slurry bypassing, drill rod being fixed, and wellbore being scrapped during high-pressure grouting of flower pipes. At the same time, the backward segmented slot grouting method can maximize the grouting pressure, perform high-pressure grouting, split the formation, and improve the grouting effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings: Figure 1 This is a schematic diagram of a three-split casing and a two-split casing in use according to an embodiment of the present invention.

[0018] Figure 2 Schematic diagram of each section of the casing according to an embodiment of the present invention.

[0019] Figure 3 This is a schematic diagram of a cutting knife being fed into the bottom of a three-open casing according to an embodiment of the present invention.

[0020] In the figure: 1, double-slit casing; 2, triple-slit casing; 3, drill pipe; 4, cutter; 41, upper joint; 5, cutting slot; 6, formation; 42, piston shaft; 43, cutter head; 44, spring; 7, liner hanger. DETAILED DESCRIPTION

[0021] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0022] See also Figure 1-3 The present invention provides a three-opening casing slot grouting method for long-distance directional drilling in deep-buried broken strata. The long-distance directional grouting hole on the ground is an L-shaped structure, and the wellbore structure is designed with three openings, one opening being a vertical section, the second opening being an inclined section, and the third opening being a horizontal grouting section. The method includes the following steps: S1. Grouting of the three horizontal sections: First, drill holes in sections (30m-200m). Under the conditions allowed by the stratum 6, drill holes as long as possible in each section. If leakage occurs, grouting is carried out (grouting pressure 3-6Mpa). Ensure the surrounding rock is stable and then carry out hole grouting; S2. Lower the ternary casing 2 into the secondary casing 1, seal the joint between the secondary casing 1 and the ternary casing 2, and then cement the ternary casing 2; S3, connecting the drill rod 3 to the upper joint 41 of the cutter 4, clamping the drill rod 3 on the upper joint 41, and moving the cutter 4 through the drill rod 3 to the position to be cut at the bottom of the three-open casing 2, thereby dividing the three-open casing 2 into multiple sections; S4, start the pump circulation, use the cutter 4 to cut the three-open casing 2 with a slit 5, after the previous slit 5 operation is completed, the position of the cutter 4 is moved back according to the slit 5 spacing, and the slit 5 operation is continued until the slit 5 of the casing section is completed and the drilling is started; S5. After the drilling is completed, the ground hole is grouting. The slurry enters the formation 6 through the double-opening casing 1, the triple-opening casing 2 and the cut slit 5. When the grouting standard is reached, the grouting is completed. S6. Repeat steps S4-S5 to complete the slits 5 of the three-section casing 2, and complete grouting of each slit 5 after each section of the casing is slit 5.

[0023] After the three-opening hole grouting, the three-opening casing 2 is lowered, the three-opening casing 2 is segmented, and a cutter 4 for cutting slits 5 in the three-opening casing 2 is lowered through the drill rod 3. The backward segmented cutting slits 5 are grouting. After the cutting slits 5 of each section of the casing are completed, the cutter 4 and the drill rod 3 are taken out, and the ground hole grouting is carried out. The slurry enters the formation 6 through the two-opening casing 1, the three-opening casing 2 and the cut slits 5. After the grouting standard is reached, the grouting of the casing section is completed. Thereafter, the cutter 4 is sent into the three-opening casing 2 again through the drill rod 3, and the next section of the casing section after grouting is cut 5 until the backward cutting slit 5 grouting of the three-opening casing 2 is completed. Firstly, it can solve the problems of repeated hole sweeping, new hole drilling, drill sticking, pressure attenuation during long horizontal grouting sections, and the inability to accurately determine the actual grouting pressure in the existing technology. It also solves the problems of grouting holes being punctured, slurry bypassing, drill rod 3 being stuck, and wellbore being scrapped during high-pressure grouting with flower pipes. Secondly, by segmenting the three-open casing 2, the length of the pipeline for a single grouting can be reduced, thereby maximizing the grouting pressure, performing high-pressure grouting, and splitting the bottom layer outside the three-open casing 2, thereby improving the grouting effect.

[0024] In one embodiment, the step S4 specifically includes the following steps: S41, start the pump cycle, push the piston shaft 42 forward, so that the cutter head 43 of the cutter 4 opens outward, and rotates by opening the drill pipe 3 to cut the position to be cut on the three-open casing 2. The cutter 4 is a hydraulic cutter 4; S42. After cutting for 5-10 minutes, observe the change of torque. When the torque decreases or the turntable chain jumps, the sensitive needle flashes, indicating that the three-way sleeve 2 is cut; S43, turn off the pump, the spring 44 pulls the piston shaft 42 back, the cutter head 43 returns to its original position, and the cutting is completed at this position; S44, the position of the cutter 4 is retracted according to the spacing of the slits 5, and moved to the rear position of the slits 5 to be cut, and the slits 5 are continued until the slits 5 of the casing section are cut and the drill is pulled out. In this design, by opening the cutter head 43 of the cutter 4 outward, the cutter 4 can be driven to cut the position to be cut on the three-way opening casing 2 during the rotation of the drill rod 3, and by observing the change in torque, it is convenient to determine whether the three-way opening casing 2 is cut. After the three-way opening casing 2 is cut, the cutter head 43 is reset by turning off the pump, and then the position of the cutter 4 is retracted according to the preset spacing of the slits 5 until the cutter 4 moves to the rear position to be cut, and the slit 5 device is continued. After the slits 5 of the casing section are cut, the drill rod 3 and the cutter 4 are removed.

[0025] In one embodiment, the length of each casing section in step S4 is 30-60 m, and the spacing between the slits 5 is 1-2 m. This design facilitates grouting by setting the length of each casing section to 30-60 m, ensures grouting pressure, and allows high-pressure grouting to be performed, thereby splitting the outer bottom layer of the three-open casing 2 and improving the grouting effect.

[0026] In one embodiment, the length of the slit 5 is 1 / 3-2 / 3 of the circumference of the cross section of the three-opening casing 2, and the width is 1 cm. This design, by limiting the length and width of the slit 5, can facilitate grouting through the slit 5 into the bottom layer, thereby facilitating the grouting work.

[0027] In one embodiment, in step S2, a liner hanger 7 is used to seal the double-open casing 1 and the triple-open casing 2. This design ensures that the triple-open casing 2 can be reused by sealing the gap between the double-open casing 1 and the triple-open casing 2, facilitating the grouting process.

[0028] In one embodiment, the two-opening casing 1 overlaps with the three-opening casing 2 by 10-20m. In this design, the two-opening casing 1 and the three-opening casing 2 overlap by 10-20m, which can further ensure the progress of the grouting process.

[0029] In one embodiment, in the step S2, the specific method of cementing is to fill the annular space of the three-open casing 2 with clay cement slurry, and the clay cement slurry has a density of 1.18-1.2×103 kg / m 3 Clay slurry, 350-500 kg / m 3 of cement and 5 L / m 3 With this design, by cementing the three-open casing 2 with clay cement slurry, a protective layer with a certain strength can be provided on the outside of the three-open casing 2. Under a certain pressure, the filler can be pressed open for horizontal grouting, and during high-pressure grouting, the slurry can be prevented from flowing out of the ground along the hole wall or the pipe wall.

[0030] In one embodiment, during the process of feeding the drill rod 3 in step S3 and pulling out the drill rod in step S4, the pump is in a closed state. This design ensures that the process of feeding the drill rod 3 and pulling out the drill rod is carried out safely.

[0031] In one embodiment, during the cutting process at S42, the pump pressure and displacement should be uniform and stable, allowing for smooth operation to prevent damage to the cutter head 43. This design facilitates the slitting operation 5 and prevents damage to the cutter head 43 by ensuring uniform and stable pump pressure and displacement, allowing for smooth operation.

[0032] The proportions of clay cement slurry are shown in the following table:

[0033] The above ratios can ensure stable cementing of the three-opening casing during use.

[0034] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

Claims

1. A three-opening casing slot grouting method for long-distance directional drilling in deep-buried broken formations. The ground long-distance directional grouting hole is an L-shaped structure with a three-opening wellbore structure design. The first opening is a vertical section, the second opening is a deflection section, and the third opening is a horizontal grouting section. It is characterized by: The steps include: S1, three-opening horizontal section grouting, first carry out segmented drilling and hole grouting; S2, lowering the three-open casing (2) from the two-open casing (1), sealing the connection between the two-open casing (1) and the three-open casing (2), and then cementing the three-open casing (2); S3, connecting the drill rod (3) to the upper joint (41) of the cutter (4), and sending the cutter (4) to the position to be cut at the bottom of the three-open casing (2) through the drill rod (3), so as to divide the three-open casing (2) into multiple sections; S4, start the pump circulation, use the cutter (4) to cut the three-open casing (2) with a slit (5), after the previous slit (5) operation is completed, the position of the cutter (4) is moved back according to the slit (5) spacing, and the slit (5) operation is continued until the slit (5) of the casing section is completed and the drilling is started; S5. After the drilling is completed, a hole grouting device is installed at the wellhead and connected to the double-opening casing (1) by threaded connection. Grouting is carried out from the hole grouting device on the ground. The slurry is transported through the double-opening casing (1) and the triple-opening casing (2) to the casing slit (5) and enters the formation (6). When the grouting standard is reached, the grouting is terminated. S6. Repeat steps S4-S5 to complete the slitting (5) of the three-section casing (2), and complete the grouting of each slit (5) after each section of casing is slit (5).

2. The method for slitting and grouting three-way casing in deep-buried and broken strata long-distance directional drilling according to claim 1 is characterized in that: The S4 step specifically includes the following steps: S41, start the pump circulation, push the piston shaft (42) forward, so that the cutter head (43) of the cutter (4) opens outward, and rotates by opening the drill rod (3) to cut the position to be cut on the three-open casing (2); S42. After cutting for 5-10 minutes, observe the change of torque. When the torque decreases or the turntable chain jumps, the sensitive needle flashes, indicating that the three-opening casing (2) is cut; S43, turn off the pump, the spring (44) pulls the piston shaft (42) back, the cutter head (43) resets, and the cutting is completed at this position; S44, the position of the cutting knife (4) is retreated according to the spacing of the cutting seams (5), moved to the rear position of the cutting seams (5), and the cutting seams (5) are continued until the cutting seams (5) of the section of casing are completed and then the drilling is started.

3. The method for slitting and grouting three-way casing in deep-buried and broken strata long-distance directional drilling according to claim 1 is characterized in that: In the step S4, the length of each casing section is 30-60 m, and the spacing between the slits (5) is 1-2 m.

4. The method for directional drilling three-way casing slot grouting in deep-buried broken strata for long distances according to claim 3 is characterized in that: The length of the slit (5) is 1 / 3-2 / 3 of the circumference of the cross section of the three-open casing (2), and the width of the slit is 1 cm.

5. The method for three-slot grouting in deep-buried and broken strata long-distance directional drilling according to claim 1 is characterized in that: In the step S2, a tail pipe hanger (7) is used to seal the double-open casing (1) and the triple-open casing (2).

6. The method for three-slot grouting in deep-buried and broken strata long-distance directional drilling according to claim 1 is characterized by: The two-open casing (1) and the three-open casing (2) overlap by 10-20m.

7. The method for slitting and grouting three-way casing in deep-buried and broken strata long-distance directional drilling according to claim 1 is characterized by: In the step S2, the specific method of cementing is to fill the annular space of the three-open casing (2) with clay cement slurry.

8. The method for three-slot grouting in deep-buried and broken strata long-distance directional drilling according to claim 7 is characterized in that: The clay cement slurry has a density ranging from 1.18 to 1.2×103 kg / m 3 Clay slurry, 350-500kg / m 3 of cement and 5 L / m 3 water glass.

9. The method for three-slot grouting in deep-buried and broken strata long-distance directional drilling according to claim 2 is characterized by: During the process of feeding the drill rod (3) in S3 and the process of pulling out the drill in S4, the pump is in a closed state.

10. The method for three-slot grouting in deep-buried and broken strata long-distance directional drilling according to claim 2, characterized in that: During the cutting process of S42, a smooth operation is performed to avoid damage to the cutter head (43).

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