Packing and grouting device and method for plugging poor drilling confined water layer

Abstract

The invention relates to the technical field of unsealing of bad drill holes caused by hidden disasters of mines, and discloses a sealing and grouting device and method for sealing a confined aquifer of a bad drill hole, the sealing and grouting device comprises an inner barrel, the outer part of the inner barrel is sleeved with a left-hand thread sleeve, the outer part of the left-hand thread sleeve is in threaded connection with an outer barrel, and the inner barrel is slidably inserted into the outer barrel; the inner barrel comprises an upper connecting coupling, a six-edge short section, an inner barrel upper limiting step, an upper packing rubber barrel inner barrel liquid inlet hole, an inner barrel grouting hole and a lower packing rubber barrel inner barrel liquid inlet hole. The outer barrel comprises a left-hand female buckle, an upper packing rubber barrel and a lower packing rubber barrel are installed on the outer wall of the outer barrel, and an upper packing rubber barrel liquid inlet one-way valve is installed on the barrel wall of the outer barrel. According to the method, grouting plugging is conducted on the target confined water layer, the outer cylinder is reserved in the hole to seal the target confined water layer, then the grouting pipe string is put down to conduct grouting on the whole shaft, triple isolation plugging of water layer grouting, outer cylinder sealing and internal grouting on the target confined water layer is achieved, and the water layer plugging effect is improved.

Description

Technical Field

[0001] This invention relates to the field of sealing technology for concealed and hazardous boreholes in mines, specifically to a grouting device and method for sealing and isolating confined water layers in hazardous boreholes. Background Technology

[0002] Hidden hazards in coal mines are geological factors that restrict safe and efficient mine production. Among them, poorly sealed boreholes are one of the main hidden sources of hazards. In recent years, relevant national departments have issued a series of notices and standards, including the "Specifications for the Survey of Hidden Hazards in Mines," requiring mining enterprises to conduct systematic surveys and remediation of various hidden hazards. Mining operations are prohibited in areas that have not been explored or properly remediated. Against this backdrop, major mining groups and research institutions have strengthened their efforts to remediate poorly sealed boreholes to ensure coal mine production safety.

[0003] Currently, the commonly used method in the industry for treating poorly sealed boreholes is to reopen the borehole, then lower a string of tubing to the bottom, and inject sealing materials such as cement grout into the entire borehole from bottom to top until the borehole opening. This method is effective for boreholes with simple hydrogeological conditions. However, when the borehole connects to a high-pressure confined aquifer, this full-hole grouting method has limitations. On the one hand, high-pressure, high-flow-rate groundwater can scour and migrate the unsolidified sealing grout, easily causing discontinuous blockages and leading to the failure of the aquifer sealing operation. On the other hand, in order to force the grout into the target aquifer, high pressure needs to be applied to the entire wellbore, which can cause pressure perforation or leakage in other strata above the confined aquifer, especially those with weaker structural strength, thus compromising the overall stability of the wellbore.

[0004] Specifically, existing full-bore grouting methods lack the ability to isolate different pressure zones within the borehole. When directly grouting the entire wellbore containing a high-pressure aquifer, the dynamic scouring effect of the high-pressure water flow dilutes and carries away the uncured sealing grout, preventing it from effectively bonding at the target location and forming a discontinuous seal, ultimately leading to sealing failure and leaving water leakage channels. Simultaneously, to overcome the high pressure of the confined aquifer for grout injection, the high grouting pressure applied throughout the entire wellbore will indiscriminately act on the upper low-pressure or structurally fragile formations, posing a risk of wellbore perforation and formation fracturing. This not only causes grout loss but also damages the original formation structure, creating new artificial water-conducting channels, thus increasing the complexity of water hazard control. Therefore, how to effectively isolate different pressure systems within the borehole while reliably locating and sealing the target confined aquifer is a problem that needs to be solved in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a sealing grouting device and method for sealing confined aquifers in poorly sealed boreholes. This solves the problems of existing full-hole grouting methods, which cannot isolate the pressure system inside the borehole, are prone to slugging when sealing high-pressure aquifers, leading to sealing failure, and the risk of penetrating the upper formation during overall pressure-locked grouting.

[0006] To achieve the above objectives, the present invention provides a grouting device for sealing and isolating confined aquifers in poorly drilled boreholes, comprising an inner cylinder, an outer sleeve sleeved on the outside of the inner cylinder, an outer cylinder being threaded onto the outside of the outer sleeve, and the inner cylinder being slidably inserted inside the outer cylinder. The inner cylinder includes an upper connecting coupling, a hexagonal short section is installed below the upper connecting coupling, an upper limit step of the inner cylinder is connected below the hexagonal short section, and an inner cylinder liquid inlet hole, an inner cylinder grouting hole and a lower sealing rubber tube inner cylinder liquid inlet hole are installed in sequence below the upper limit step of the inner cylinder. The outer cylinder includes a reverse buckle nut, which is disposed inside the outer cylinder. An upper sealing rubber tube and a lower sealing rubber tube are installed on the outer wall of the outer cylinder. From top to bottom, a liquid inlet check valve for the upper sealing rubber tube, a grouting hole check valve for the outer cylinder, and a liquid inlet check valve for the lower sealing rubber tube are also installed on the cylinder wall of the lower sealing rubber tube.

[0007] Preferably, the reverse sleeve includes a hexagonal inner cavity that mates with the hexagonal short section, and the outer wall of the reverse sleeve is fitted with a reverse male buckle that mates with the reverse female buckle; a straightening sleeve is provided at the lower end of the reverse male buckle.

[0008] Preferably, the inner cylinder further includes a lower limit step, which is located below the liquid inlet hole of the lower sealing rubber cylinder. An inner cylinder circulation hole is also provided below the liquid inlet hole of the lower sealing rubber cylinder. The inner wall of the outer cylinder is also provided with a lower limit step, and a guide head is connected to the lower end of the lower limit step.

[0009] Preferably, the upper limit step of the inner cylinder and the lower end face of the straightening cylinder form an upper limiting structure; the lower limit step of the inner cylinder and the lower limit step of the outer cylinder form a lower limiting structure.

[0010] Preferably, the liquid inlet hole of the upper sealing rubber tube inner cylinder, the grouting hole of the inner cylinder and the liquid inlet hole of the lower sealing rubber tube inner cylinder are arranged axially from top to bottom, and the liquid inlet check valve of the upper sealing rubber tube, the grouting hole check valve of the outer cylinder and the liquid inlet check valve of the lower sealing rubber tube are arranged axially from top to bottom.

[0011] Preferably, the external thread of the reverse-threaded male is connected to the inside of the reverse-threaded female; the upper end of the reverse-threaded sleeve is also provided with a tapered limit, and the upper end of the inner wall of the outer cylinder is also formed with a tapered opening that cooperates with the tapered limit.

[0012] Preferably, the inner cylinder further includes an expansion groove for the liquid inlet hole of the upper sealing rubber tube, which is located outside the liquid inlet hole of the upper sealing rubber tube; an expansion groove for the grouting hole of the inner cylinder is provided outside the grouting hole of the inner cylinder; and an expansion groove for the liquid inlet hole of the lower sealing rubber tube is provided outside the liquid inlet hole of the inner cylinder. The expansion grooves for the liquid inlet hole of the upper sealing rubber tube, the grouting hole, and the liquid inlet hole of the lower sealing rubber tube are all annular grooves.

[0013] Preferably, the inner cavity of the upper sealing rubber tube is connected to the liquid inlet check valve of the upper sealing rubber tube; the inner cavity of the lower sealing rubber tube is connected to the liquid inlet check valve of the lower sealing rubber tube.

[0014] Preferably, the fluid conduction direction of the liquid inlet check valve of the upper sealing rubber cylinder is towards the inner cavity of the upper sealing rubber cylinder; the fluid conduction direction of the liquid injection hole check valve of the outer cylinder is towards the outside of the outer cylinder; and the fluid conduction direction of the liquid inlet check valve of the lower sealing rubber cylinder is towards the inner cavity of the lower sealing rubber cylinder.

[0015] The present invention also provides a method for sealing and grouting confined aquifers in poorly drilled boreholes, comprising the following steps: S1. Use a drill rod to lower the device to the target confined aquifer location; S2. Raise or lower the inner cylinder to the upper limiting structure, so that the fluid enters the upper and lower sealing rubber cylinders in sequence through the inlet hole of the upper sealing rubber cylinder, the inlet hole of the lower sealing rubber cylinder, the inlet check valve of the upper sealing rubber cylinder, and the inlet check valve of the lower sealing rubber cylinder, causing the upper and lower sealing rubber cylinders to expand, thereby isolating the target pressurized water layer from other layers in the wellbore, and fixing the outer cylinder to the borehole wall; S3. Move the inner cylinder down to the lower limiting structure so that the grout is discharged outward through the one-way valves of the inner cylinder grouting hole and the outer cylinder grouting hole to grout and seal the target pressurized water layer. S4. After the grouting and sealing operation is completed, rotate the inner cylinder forward. Through the cooperation of the hexagonal short section and the hexagonal inner cavity, the reverse sleeve is rotated forward, so that the reverse sleeve is disengaged from the outer cylinder. Then, it is lifted up to retrieve the inner cylinder and the reverse sleeve. S5. The grouting pipe string is lowered to the bottom of the hole through the outer cylinder left in the hole, and then grout is injected from bottom to top to the hole opening using the grouting pipe string to seal the outer cylinder and the entire well barrel inside the hole, thus completing the hole sealing operation.

[0016] Compared with the prior art, the present invention has the following advantages: 1. This invention first seals the target confined aquifer with grouting by setting up a sealing grouting device, then recovers the inner cylinder and the reverse sleeve so that the outer cylinder remains in the hole to form a seal for the target confined aquifer, and finally grouts the entire wellbore by lowering the grouting pipe string. This achieves triple isolation and sealing of the target confined aquifer by grouting the water layer, sealing the outer cylinder and grouting the inside, thus improving the sealing effect of the water layer.

[0017] 2. This invention, by setting a hexagonal short section on the inner cylinder and cooperating with the hexagonal inner cavity of the reverse sleeve, and setting a reverse male and reverse female thread between the reverse sleeve and the outer cylinder, allows the reverse sleeve to be detached from the outer cylinder by rotating the inner cylinder forward after the grouting and sealing of the target confined water layer is completed, so as to recover the inner cylinder and the reverse sleeve. This not only allows the outer cylinder to remain in the hole to form an effective seal, but also supports the sequential isolation and sealing of multiple confined water layers from bottom to top, thus expanding the applicability of the device.

[0018] 3. By setting an upper limiting structure and a lower limiting structure, and allowing the inner cylinder to slide axially, this invention enables the connection of the liquid inlet channel for expansion of the rubber cylinder or the discharge channel for grouting by lifting or lowering the inner cylinder to different limiting structures. Thus, the switching between the two working modes of expansion sealing and grouting can be completed by simple axial movement, simplifying the operation process. Attached Figure Description

[0019] Figure 1 This is an overall cross-sectional view of the present invention; Figure 2 This is a cross-sectional view of the inner cylinder of the present invention; Figure 3 This is a cross-sectional view of the reverse-locking sleeve of the present invention; Figure 4 This is a cross-sectional view of the outer cylinder of the present invention; Figure 5 This is a schematic diagram of the wellbore structure and water layer for sealing poorly drilled holes according to the present invention; Figure 6 This is a schematic diagram of the grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to the present invention. Figure 7 This is a schematic diagram of the expansion sealing of the grouting device for sealing confined water layers in poorly drilled boreholes according to the present invention; Figure 8 This is a schematic diagram of the grouting process for the sealing and grouting device for confined aquifers in poorly drilled boreholes according to the present invention. Figure 9 A schematic diagram is provided for the grouting device for sealing confined aquifers in poorly drilled boreholes according to the present invention; Figure 10 This is a schematic diagram of the double-layer construction of the grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to the present invention; Figure 11 This is a schematic diagram of the grouting pipe string extending to the bottom of the hole according to the present invention; Figure 12 This is a schematic diagram of the sealing state of the defective hole in the present invention; Figure 13 This is a flowchart of the grouting process for sealing and isolating confined water layers in poorly sealed boreholes according to the present invention.

[0020] Among them, 1. Inner cylinder; 1-1. Upper connecting coupling; 1-2. Hexagonal short section; 1-3. Upper limit step of inner cylinder; 1-4. Expansion groove of liquid inlet hole of inner cylinder of upper sealing septum tube; 1-5. Liquid inlet hole of inner cylinder of upper sealing septum tube; 1-6. Expansion groove of grouting hole of inner cylinder; 1-7. Grouting hole of inner cylinder; 1-8. Expansion groove of liquid inlet hole of inner cylinder of lower sealing septum tube; 1-9. Liquid inlet hole of inner cylinder of lower sealing septum tube; 1-10. Lower limit step of inner cylinder; 1-11. Inner cylinder circulation... 1. Ring hole; 2. Reverse sleeve; 2-1. Conical limit; 2-2. Reverse male thread; 2-3. Hexagonal inner cavity; 2-4. Straightening cylinder; 3. Outer cylinder; 3-1. Conical opening; 3-2. Reverse female thread; 3-3. Upper sealing diaphragm cylinder; 3-4. Upper sealing diaphragm cylinder inlet check valve; 3-5. Outer cylinder grouting hole check valve; 3-6. Lower sealing diaphragm cylinder; 3-7. Lower sealing diaphragm cylinder inlet check valve; 3-8. Outer cylinder lower limit step; 3-9. Guide head. Detailed Implementation

[0021] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings and examples.

[0022] Please see the appendix Figure 1 This invention provides a grouting device for sealing and sealing confined aquifers in poorly drilled boreholes, comprising an inner cylinder 1, a reverse sleeve 2, and an outer cylinder 3; the reverse sleeve 2 is sleeved on the outside of the inner cylinder 1, and the outer cylinder 3 is threadedly connected to the outside of the reverse sleeve 2; the inner cylinder 1 is slidably inserted inside the outer cylinder 3.

[0023] Specifically, the core structure of this device lies in the recyclable inner assembly consisting of the inner cylinder 1 and the reverse sleeve 2, and the outer cylinder 3 which can be left inside the borehole. This design of separating the inner and outer cylinders is the structural basis for achieving triple isolation and sealing. The process is as follows: first, the target confined aquifer is grouted and sealed; second, the outer cylinder 3 left inside the borehole is used for physical isolation; and finally, the entire wellbore is internally grouted by lowering the tubing string.

[0024] Please see the appendix Figure 1 and attached Figure 2The inner cylinder 1 includes an upper connecting coupling 1-1. Below the upper connecting coupling 1-1, a hexagonal short section 1-2 is installed. Below the hexagonal short section 1-2, an upper limit step 1-3 is connected. Below the upper limit step 1-3, an inner cylinder inlet hole 1-5 for the upper sealing septum tube, an inner cylinder grouting hole 1-7, and an inner cylinder inlet hole 1-9 for the lower sealing septum tube are sequentially installed. The inner cylinder 1 also includes a lower limit step 1-10, which is located below the inner cylinder inlet hole 1-9 for the lower sealing septum tube. Below the inner cylinder inlet hole 1-9 for the lower sealing septum tube, there is also an opening... The inner cylinder 1 is provided with an inner cylinder circulation hole 1-11. The inner cylinder 1 also includes an expansion groove 1-4 for the liquid inlet hole of the upper sealing rubber tube inner cylinder. The expansion groove 1-4 for the liquid inlet hole of the upper sealing rubber tube inner cylinder is opened outside the liquid inlet hole 1-5 of the upper sealing rubber tube inner cylinder. An expansion groove 1-6 for the grouting hole 1-7 of the inner cylinder is opened outside the grouting hole 1-9 of the lower sealing rubber tube inner cylinder is opened outside the grouting hole 1-8 of the lower sealing rubber tube inner cylinder. The expansion grooves 1-4, 1-6, and 1-8 of the upper sealing rubber tube inner cylinder, the grouting hole, and the lower sealing rubber tube inner cylinder are all annular grooves.

[0025] Specifically, the inner cylinder 1 is the core component for performing operations and conveying fluids. The expansion grooves 1-4 (upper sealing diaphragm inner cylinder inlet hole expansion groove 1-6), 1-8 (lower sealing diaphragm inner cylinder inlet hole expansion groove 1-8) on the inner cylinder serve as annular grooves, respectively surrounding the corresponding functional channels. By forming annular connecting spaces, this ensures that when the inner cylinder 1 slides to the designated working position, the fluid channels can be reliably aligned and form a large-area connection, improving the efficiency of fluid exchange. The inner cylinder circulation hole 1-11 is sealed by the inner wall of the outer cylinder 3 during expansion sealing and grouting to maintain system pressure; when the operation is completed and the inner cylinder 1 is lifted and retracted, this hole moves out of the outer cylinder 3, its sealing state is released, thus forming a circulation channel for flushing and cleaning residual grout and other sealing materials in the inner cylinder 1.

[0026] Please see the appendix Figure 1 and attached Figure 3 The reverse sleeve 2 includes a hexagonal inner cavity 2-3, which mates with a hexagonal short section 1-2. The outer wall of the reverse sleeve 2 is fitted with a reverse male thread 2-2 that mates with a reverse female thread 3-2. The external thread of the reverse male thread 2-2 is connected to the interior of the reverse female thread 3-2. A straightening sleeve 2-4 is provided at its lower end. A tapered limiter 2-1 is also provided at the upper end of the reverse sleeve 2.

[0027] Specifically, the reverse sleeve 2 is a key torque transmission and limiting component connecting the inner cylinder 1 and the outer cylinder 3, and enabling their final separation. Through the cooperation of the hexagonal inner cavity 2-3 and the hexagonal short section 1-2 on the inner cylinder 1, it can transmit the positive rotational torque from the inner cylinder 1 to itself, thereby causing the reverse male buckle 2-2 on its exterior to unscrew from the reverse female buckle 3-2 on the outer cylinder 3, thus achieving the separation of the inner cylinder 1 and outer cylinder 3 and the retraction of the inner cylinder 1. Simultaneously, the sleeve can slide axially on the hexagonal short section 1-2. Its lower end, the centering sleeve 2-4, plays a guiding and centering role during connection and separation. Its lower end face, together with the upper limit step 1-3 of the inner cylinder, constitutes the upper limiting structure of the device. The tapered limit 2-1 at its upper end, cooperating with the tapered opening 3-1 of the outer cylinder 3, precisely controls the initial buckle position during installation.

[0028] Please see the appendix Figure 1 and attached Figure 4 The outer cylinder 3 is provided with a reverse buckle 3-2 inside, and a conical opening 3-1 that cooperates with the conical limit 2-1 is formed at the upper end of the inner wall. The outer wall of the outer cylinder 3 is equipped with an upper sealing rubber tube 3-3 and a lower sealing rubber tube 3-6. The upper sealing rubber tube liquid inlet check valve 3-4, the outer cylinder grouting hole check valve 3-5 and the lower sealing rubber tube liquid inlet check valve 3-7 are also installed on the cylinder wall of the outer cylinder 3 from top to bottom. The inner wall of the outer cylinder 3 is also provided with a lower limit step 3-8. The lower end of the lower limit step 3-8 is connected to a guide head 3-9. The inner cavity of the upper sealing rubber cylinder 3-3 is connected to the upper sealing rubber cylinder inlet check valve 3-4; the inner cavity of the lower sealing rubber cylinder 3-6 is connected to the lower sealing rubber cylinder inlet check valve 3-7. The fluid conduction direction of the upper sealing rubber cylinder inlet check valve 3-4 is towards the inner cavity of the upper sealing rubber cylinder 3-3; the fluid conduction direction of the outer cylinder grouting hole check valve 3-5 is towards the outside of the outer cylinder 3; the fluid conduction direction of the lower sealing rubber cylinder inlet check valve 3-7 is towards the inner cavity of the lower sealing rubber cylinder 3-6.

[0029] Specifically, the outer cylinder 3 is the executing component in the device that performs sealing, grouting, and ultimately leaves a permanent isolation channel within the borehole. The upper sealing rubber cylinder 3-3 and lower sealing rubber cylinder 3-6, fixed at their upper and lower positions on its outer wall, expand upon receiving fluid through the upper sealing rubber cylinder inlet check valve 3-4 and lower sealing rubber cylinder inlet check valve 3-7, thus adhering tightly to the borehole wall to achieve vertical isolation of the target pressurized aquifer and anchoring the outer cylinder 3 itself in a predetermined position. Three check valves installed on the cylinder wall are connected by threads to precisely control the fluid flow direction: the upper sealing rubber cylinder inlet check valve 3-4 and lower sealing rubber cylinder inlet check valve 3-7 ensure that fluid can only enter the corresponding rubber cylinder, while the outer cylinder grouting hole check valve 3-5 ensures that grout can only be discharged from the outer cylinder 3 to the formation, preventing backflow. The guide head 3-9 at the lower end provides guidance for the smooth lowering of the device.

[0030] Please see the appendix Figure 1 - Appendix Figure 4The upper limit step 1-3 of the inner cylinder and the lower end face of the straightening cylinder 2-4 form the upper limiting structure; the lower limit step 1-10 of the inner cylinder and the lower limit step 3-8 of the outer cylinder form the lower limiting structure; the liquid inlet hole 1-5 of the inner cylinder of the upper sealing septum cylinder, the grouting hole 1-7 of the inner cylinder of the inner cylinder and the liquid inlet hole 1-9 of the inner cylinder of the lower sealing septum cylinder are arranged axially from top to bottom; the liquid inlet check valve 3-4 of the upper sealing septum cylinder, the grouting hole check valve 3-5 of the outer cylinder and the liquid inlet check valve 3-7 of the lower sealing septum cylinder are arranged axially from top to bottom.

[0031] Specifically, the switching of the device's working mode depends on the axial sliding of the inner cylinder 1 relative to the outer cylinder 3, and is precisely positioned by two sets of upper and lower limiting structures. When the inner cylinder 1 is lifted or lowered, so that its upper limit step 1-3 contacts the lower end face of the straightening cylinder 2-4 of the reverse sleeve 2, the upper limiting structure is reached. At this time, the liquid inlet holes 1-5 and 1-9 of the upper and lower sealing rubber tubes on the inner cylinder 1 are precisely aligned with the liquid inlet check valves 3-4 and 3-7 of the upper and lower sealing rubber tubes on the outer cylinder 3, forming a liquid inlet channel to achieve the expansion and sealing of the rubber tube, while the grouting hole 1-7 of the inner cylinder is in a non-aligned closed state. Conversely, when the inner cylinder 1 is moved down so that its lower limit step 1-10 contacts the lower limit step 3-8 on the inner wall of the outer cylinder 3, the lower limit structure is reached. At this time, the grouting hole 1-7 of the inner cylinder is precisely aligned with the one-way valve 3-5 of the grouting hole of the outer cylinder, forming a grouting channel to seal the water layer. Meanwhile, the liquid inlet hole 1-5 of the inner cylinder of the upper sealing rubber tube and the liquid inlet hole 1-9 of the inner cylinder of the lower sealing rubber tube are in a non-aligned closed state.

[0032] Please see the appendix Figure 5 - Appendix Figure 13 The present invention also provides a method for sealing and grouting confined aquifers in poorly drilled boreholes, comprising the following steps: S1. Use drill pipe to lower the device to the target confined aquifer location; S2. Raise or lower the inner cylinder 1 to the upper limiting structure, so that the fluid enters the upper sealing rubber cylinder 3-3 and the lower sealing rubber cylinder 3-6 in sequence through the upper sealing rubber cylinder inner cylinder inlet hole 1-5, the lower sealing rubber cylinder inner cylinder inlet hole 1-9, the upper sealing rubber cylinder inlet check valve 3-4 and the lower sealing rubber cylinder inlet check valve 3-7, causing the upper sealing rubber cylinder 3-3 and the lower sealing rubber cylinder 3-6 to expand, thereby isolating the target pressurized water layer from other layers in the wellbore, and fixing the outer cylinder 3 to the borehole wall; S3. Move the inner cylinder 1 down to the lower limiting structure so that the grout can be discharged outward through the inner cylinder grouting hole 1-7 and the outer cylinder grouting hole one-way valve 3-5 to grout and seal the target pressurized water layer. S4. After the grouting and sealing operation is completed, rotate the inner cylinder 1 forward. Through the cooperation of the hexagonal short section 1-2 and the hexagonal inner cavity 2-3, the reverse sleeve 2 is rotated forward, so that the reverse sleeve 2 is separated from the outer cylinder 3. Then lift it up to retrieve the inner cylinder 1 and the reverse sleeve 2. S5. The grouting pipe string is lowered to the bottom of the hole through the outer cylinder 3 left in the hole. Then, grout is injected from bottom to top to the hole opening using the grouting pipe string to seal the outer cylinder 3 and the entire wellbore inside the hole, thus completing the hole sealing operation.

[0033] Specifically, in step S1, the entire device is lowered using a drill rod. The guide head 3-9 at the lower end of the device is used to guide the device to reach the predetermined depth smoothly, and the upper sealing septum 3-3 and the lower sealing septum 3-6 are positioned above and below the target pressurized water layer, respectively.

[0034] In step S2, fluid is pumped into the inner cylinder 1 hydraulically, causing the upper and lower sealing rubber sleeves to expand and adhere tightly to the borehole wall. This process not only effectively isolates the target pressurized water layer but also firmly anchors the outer cylinder 3 to the borehole wall, providing stable support for subsequent grouting operations.

[0035] In step S3, the grout is pumped into the inner cylinder 1. After the inner cylinder 1 reaches the lower limiting structure, the grout is discharged from the connected grouting channel. It not only enters the target confined aquifer for sealing, but also fills the annular space between the outer cylinder 3 and the hole wall, thus achieving the first grouting and sealing of the aquifer.

[0036] In step S4, after grouting is completed, the drill rod is operated to rotate the inner cylinder 1 clockwise. This torque is transmitted to the reverse sleeve 2 through the hexagonal short section 1-2, causing it to unscrew from the reverse nut 3-2 of the outer cylinder 3, thereby releasing the restriction on the upward movement of the inner cylinder 1. During the process of lifting the inner cylinder 1 and the reverse sleeve 2, the inner cylinder circulation hole 1-11, which was previously sealed by the inner wall of the outer cylinder 3, is exposed, forming a circulation channel to facilitate flushing and cleaning of residual grout in the inner cylinder 1.

[0037] In step S5, after the inner cylinder 1 and the reverse sleeve 2 are completely recovered, the outer cylinder 3 left in the borehole acts as a permanent physical barrier, forming a second seal against the water layer. Simultaneously, its internal channels remain open, allowing new grouting tubing to pass through and reach deeper into the borehole. The final full-bore grouting operation seals the entire wellbore, including the left-in outer cylinder 3, within the borehole, forming a third layer of internal grouting seal against the water layer.

[0038] In addition, when multiple confined aquifers exist within the borehole, steps S1 to S4 can be repeated, starting from the bottom confined aquifer and proceeding upwards with isolation and grouting, leaving an outer cylinder 3 at each aquifer location. After all aquifers have been treated, step S5 is executed, where a grouting pipe string is lowered through all the left-in outer cylinders 3 to the bottom of the borehole for a one-time full-bore sealing operation.

Claims

1. A grouting device for sealing confined aquifers in poorly drilled boreholes, comprising an inner cylinder (1), characterized in that, The inner cylinder (1) is fitted with a reverse sleeve (2), and the outer cylinder (3) is threadedly connected to the outside of the reverse sleeve (2). The inner cylinder (1) is slidably inserted into the inside of the outer cylinder (3). The inner cylinder (1) includes an upper connecting coupling (1-1), a hexagonal short section (1-2) is installed below the upper connecting coupling (1-1), an upper limit step (1-3) of the inner cylinder is connected below the hexagonal short section (1-2), and an upper sealing rubber tube inner cylinder inlet hole (1-5), an inner cylinder grouting hole (1-7) and a lower sealing rubber tube inner cylinder inlet hole (1-9) are installed in sequence below the upper limit step (1-3). The outer cylinder (3) includes a reverse buckle (3-2), which is located inside the outer cylinder (3). The outer wall of the outer cylinder (3) is equipped with an upper sealing rubber tube (3-3) and a lower sealing rubber tube (3-6). The lower sealing rubber tube (3-6) is also equipped with an upper sealing rubber tube inlet check valve (3-4), an outer cylinder grouting hole check valve (3-5), and a lower sealing rubber tube inlet check valve (3-7) in sequence from top to bottom on the cylinder wall.

2. The grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to claim 1, characterized in that, The reverse sleeve (2) includes a hexagonal inner cavity (2-3), which is matched with the hexagonal short section (1-2). The outer wall of the reverse sleeve (2) is equipped with a reverse male buckle (2-2) that matches the reverse female buckle (3-2). A straightening sleeve (2-4) is provided at the lower end of the reverse male buckle (2-2).

3. A grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to claim 2, characterized in that, The inner cylinder (1) also includes an inner cylinder lower limit step (1-10), which is located below the liquid inlet hole (1-9) of the inner cylinder of the lower sealing rubber tube. An inner cylinder circulation hole (1-11) is also provided below the liquid inlet hole (1-9) of the inner cylinder of the lower sealing rubber tube. The inner wall of the outer cylinder (3) is also provided with an outer cylinder lower limit step (3-8), and a guide head (3-9) is connected to the lower end of the outer cylinder lower limit step (3-8).

4. A grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to claim 3, characterized in that, The upper limit step (1-3) of the inner cylinder and the lower end face of the straightening cylinder (2-4) constitute an upper limiting structure; the lower limit step (1-10) of the inner cylinder and the lower limit step (3-8) of the outer cylinder constitute a lower limiting structure.

5. A grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to claim 1, characterized in that, The liquid inlet holes (1-5) of the upper sealing rubber tube inner cylinder, the grouting holes (1-7) of the inner cylinder, and the liquid inlet holes (1-9) of the lower sealing rubber tube inner cylinder are arranged axially from top to bottom. The liquid inlet check valve (3-4) of the upper sealing rubber tube, the grouting hole check valve (3-5) of the outer cylinder, and the liquid inlet check valve (3-7) of the lower sealing rubber tube are arranged axially from top to bottom.

6. A grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to claim 2, characterized in that, The external thread of the reverse male thread (2-2) is connected to the inside of the reverse female thread (3-2); the upper end of the reverse sleeve (2) is also provided with a conical limit (2-1), and the upper end of the inner wall of the outer cylinder (3) is also formed with a conical opening (3-1) that cooperates with the conical limit (2-1).

7. A grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to claim 1, characterized in that, The inner cylinder (1) also includes an expansion groove (1-4) for the liquid inlet hole of the upper sealing rubber tube, which is located outside the liquid inlet hole (1-5) of the upper sealing rubber tube; an expansion groove (1-6) for the grouting hole (1-7) of the inner cylinder is provided outside; an expansion groove (1-8) for the liquid inlet hole (1-9) of the lower sealing rubber tube is provided outside; and the expansion groove (1-4) for the liquid inlet hole of the upper sealing rubber tube, the expansion groove (1-6) for the grouting hole of the inner cylinder, and the expansion groove (1-8) for the liquid inlet hole of the lower sealing rubber tube are all annular grooves.

8. A grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to claim 1, characterized in that, The inner cavity of the upper sealing rubber tube (3-3) is connected to the upper sealing rubber tube inlet check valve (3-4); the inner cavity of the lower sealing rubber tube (3-6) is connected to the lower sealing rubber tube inlet check valve (3-7).

9. A grouting device for sealing and isolating confined aquifers in poorly drilled boreholes according to claim 1, characterized in that, The fluid conduction direction of the upper sealing rubber cylinder inlet check valve (3-4) is towards the inner cavity of the upper sealing rubber cylinder (3-3); the fluid conduction direction of the outer cylinder grouting hole check valve (3-5) is towards the outside of the outer cylinder (3); the fluid conduction direction of the lower sealing rubber cylinder inlet check valve (3-7) is towards the inner cavity of the lower sealing rubber cylinder (3-6).

10. A method for sealing and isolating confined aquifers in poorly drilled boreholes, characterized in that, The method uses a grouting device for sealing confined aquifers in poorly drilled boreholes, as described in any one of claims 1-9, and includes the following steps: S1. Use a drill rod to lower the device to the target confined aquifer location; S2. Raise or lower the inner cylinder (1) to the upper limiting structure, so that the fluid enters the upper sealing rubber cylinder (3-3) and the lower sealing rubber cylinder (3-6) in sequence through the liquid inlet hole (1-5) of the inner cylinder of the upper sealing rubber cylinder, the liquid inlet hole (1-9) of the inner cylinder of the lower sealing rubber cylinder, the liquid inlet check valve (3-4) of the upper sealing rubber cylinder and the liquid inlet check valve (3-7) of the lower sealing rubber cylinder, so that the upper sealing rubber cylinder (3-3) and the lower sealing rubber cylinder (3-6) expand, thereby isolating the target pressurized water layer from other layers of the well, and fixing the outer cylinder (3) to the borehole wall; S3. Move the inner cylinder (1) down to the lower limiting structure so that the grout is discharged outward through the inner cylinder grouting hole (1-7) and the outer cylinder grouting hole check valve (3-5) to grout and seal the target pressurized water layer. S4. After the grouting and sealing operation is completed, rotate the inner cylinder (1) in the forward direction. Through the cooperation of the hexagonal short section (1-2) and the hexagonal inner cavity (2-3), drive the reverse sleeve (2) to rotate in the forward direction, so that the reverse sleeve (2) is separated from the outer cylinder (3). Then lift and retract the inner cylinder (1) and the reverse sleeve (2). S5. The grouting pipe string is lowered to the bottom of the hole through the outer cylinder (3) left in the hole, and then the grouting pipe string is used to inject grout from bottom to top to the hole opening, so as to seal the outer cylinder (3) and the entire well barrel in the hole and complete the hole sealing operation.

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