Downward water-containing gas extraction drill hole sealing device and method

Abstract

The invention belongs to the technical field of coal mine gas extraction, and particularly discloses a downward water-containing gas extraction drill hole sealing device and method. According to the downward water-containing gas extraction drill hole sealing device and method, a novel two-blocking one-discharging one-injecting mode is adopted, sealing grout is injected into the bags through the grouting pipe, the starting pressure Pb of an explosion valve is achieved, the bag is expanded, the abutting pressure between the bag and the inner wall of the drill hole reaches a set pressure value, a closed space is defined by the two expanded bags and the drill hole, and the sealing effect is achieved. The grouting pipe is communicated with the closed space; the water in the closed space is drained through the drainage end via the drainage pipe; sealing grout continues to be injected into the closed space through the grouting pipe, and when the closed space is filled with the sealing grout and the grouting pressure is expressed to be within the set pressure range, the sealing grout permeates into the drill hole surrounding rock cracks, so that the closed space and the drill hole surrounding rock cracks are fully filled with the sealing grout; and the sealing quality of the downward water-containing gas extraction drill hole is greatly improved.

Description

Technical Field

[0001] The invention belongs to the technical field of coal mine gas extraction, and in particular relates to a downward water-containing gas extraction drilling hole sealing device and method. Background Art

[0002] Borehole gas extraction is the main way to prevent and control gas disasters and develop and utilize coalbed methane resources in coal mines. The amount of gas extracted through borehole gas extraction accounts for more than 90% of the total underground gas extraction. Among them, the quality of the sealing of gas extraction boreholes directly affects the effect of borehole gas extraction. Gas extraction boreholes generally have the problem of poor sealing quality. Generally, the gas concentration in boreholes with good sealing quality is 70-90%. However, at present, there are still some mining working faces with pre-extracted gas concentrations lower than 30%, which cannot meet the requirements for preventing and controlling coal and gas outbursts. Among them, downward water-containing gas extraction boreholes are a type of borehole that is more difficult to seal, and it is difficult to achieve ideal sealing quality using the currently commonly used conventional "two blocking and one injection" sealing process. The "one plug and one injection" sealing process cannot seal the hole under pressure, the sealing pressure of the sealing section is low, and the sealing section and the cracks in the borehole surrounding rock cannot be effectively filled, and the sealing quality is still poor; the sealing process of the extraction pipe and the surrounding of the hole wrapped with water-absorbing and swelling materials, when the material meets the drilling water, absorbs water and expands to fill the drilling sealing section, can only fill the space of the drilling sealing section, and cannot effectively seal the cracks in the borehole surrounding rock, the sealing quality is poor, and the process is expensive, which is not conducive to large-scale use; the conventional "two plugs and one injection" is used to seal the borehole and then perform a secondary compensation sealing process. After the concentration of gas extracted from the borehole is significantly reduced, secondary compensation grouting sealing is performed. This process can improve the quality of drilling hole sealing to a certain extent, but the timing of the secondary compensation is difficult to grasp, the effect of improving the sealing quality is difficult to control, and the sealing process and on-site management are complicated. Summary of the invention

[0003] The purpose of the present invention is to provide a downward water-containing gas extraction borehole sealing device and method, which adopts a new "two-blocking, one-draining, and one-injecting" method to improve the sealing quality of the downward water-containing gas extraction borehole.

[0004] In order to achieve the above object, the technical solutions adopted by the present invention are as follows:

[0005] A downward water-containing gas extraction borehole sealing device, comprising:

[0006] The extraction pipe extends into the interior of the downward water-containing gas extraction borehole;

[0007] The bladder bags are provided in two pieces and are arranged at a set distance along the axial direction of the extraction pipe, and abut against the inner wall of the downward water-gas extraction borehole after expansion;

[0008] A grouting pipe extends into the downward water-containing gas extraction borehole, passes through the bag and the space between the two bags, a check valve is provided on the grouting pipe inside the bag, and a bursting valve is provided on the grouting pipe in the space between the two bags;

[0009] A grouting supply end, used to inject sealing slurry of set pressure into the grouting pipe;

[0010] A return slurry pipe extends into the downward water-bearing gas extraction borehole and passes through the outer bladder bag, and the end of the return slurry pipe is located in the space between the two bladder bags;

[0011] A drainage pipe extends into the downward water-gas extraction borehole and passes through the outer bladder bag, with the end of the drainage pipe being located in the space between the two bladder bags;

[0012] The drainage end is used to drain the water in the space between the two bladder bags through the drainage pipe.

[0013] Furthermore, the grouting supply end includes a grouting container, a grouting pump and a grouting stop valve. The grouting container contains sealed slurry. The grouting inlet of the grouting pump is connected to the grouting container via a grouting inlet pipeline. The grouting outlet of the grouting pump is connected to the grouting pipe via a grouting outlet pipeline. A grouting stop valve is arranged on the grouting outlet pipeline.

[0014] Furthermore, a grouting pressure gauge is provided on the slurry outlet pipeline.

[0015] Furthermore, the drainage end includes a water pump and a drainage stop valve, the water inlet of the water pump is connected to a drainage pipe, and the drainage stop valve is arranged on the drainage pipe.

[0016] Furthermore, a return slurry stop valve is provided on the return slurry pipe.

[0017] Furthermore, the bursting valve is located above the outer side of the inner bladder bag.

[0018] Furthermore, the end of the return slurry pipe is close to the outer bladder bag and away from the inner bladder bag.

[0019] Furthermore, the end of the drain pipe is close to the inner bladder bag and away from the outer bladder bag.

[0020] Furthermore, bag limiting plates are provided on both sides of the bag on the extraction pipe, and the grouting pipe, the return grouting pipe and the drainage pipe are all fixedly connected to the bag limiting plates.

[0021] A method for sealing a downward water-containing gas extraction borehole, using the above-mentioned downward water-containing gas extraction borehole sealing device, the method comprising the following steps:

[0022] Step 1: Sealing preparation

[0023] After the downward water-containing gas extraction borehole is formed, the extraction pipe, the bag, the grouting pipe, the return grouting pipe and the drainage pipe are extended into the downward water-containing gas extraction borehole, the grouting supply end is connected to the grouting pipe, and the drainage end is connected to the drainage pipe;

[0024] Step 2: "Two-blocking" construction

[0025] Open the grouting stop valve, start the grouting pump, and inject the sealing slurry into the bag through the grouting pipe and the check valve. When the grouting pressure gauge reaches the starting pressure P of the bursting valve, b When the grouting is stopped, close the grouting stop valve and stop the grouting pump;

[0026] Among them, the starting pressure P of the bursting valve is set b , so that the burst valve starting pressure P is expressed in the grouting pressure b When the bag expands and contacts the inner wall of the downward gas-bearing water extraction borehole, the pressure reaches the set pressure value;

[0027] Step 3: One row construction

[0028] Open the return slurry stop valve, open the drainage stop valve, start the water pump, and drain the water in the space between the two bags through the drainage pipe;

[0029] Step 4: One-shot construction

[0030] Close the drainage stop valve, stop the water pump, reopen the grouting stop valve, restart the grouting pump, and inject the sealing slurry into the space between the two bags through the grouting pipe and the bursting valve; when the sealing slurry flows out of the return grouting pipe, close the return grouting stop valve, and when the grouting pressure gauge reaches the set pressure range, close the grouting stop valve and stop the grouting pump to stop grouting.

[0031] The beneficial technical effects of the present invention are:

[0032] The present invention adopts a new "two-blocking, one-draining, one-injecting" method to first inject sealing slurry into the bag through the grouting pipe to reach the starting pressure P of the bursting valve. bThe bladder is expanded and the pressure against the inner wall of the borehole reaches a set pressure value. A closed space is defined by the two expanded bladders and the borehole, and the grouting pipe is connected to the closed space; the water in the closed space is then discharged through the drainage end through the drainage pipe; the sealing slurry is continued to be injected into the closed space through the grouting pipe. When the closed space is filled with the sealing slurry, when the grouting pressure reaches the set pressure range, the sealing slurry is allowed to penetrate into the cracks in the surrounding rock of the borehole, so that the closed space and the cracks in the surrounding rock of the borehole are fully filled with the sealing slurry, which greatly improves the sealing quality of the downward water-containing gas extraction borehole. The downward water-containing gas extraction borehole sealing device and method of the present invention fundamentally solves the problem of low sealing quality of the downward water-containing gas extraction borehole, and the device is simple, easy to construct and operate, low cost, and has high promotion and application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is a layout diagram of a sealing device for drilling a hole for extracting water-containing gas in an embodiment of the present invention;

[0034] Figure 2 It is a flowchart of a method for sealing a borehole for gas extraction from water in an embodiment of the present invention;

[0035] Reference numerals:

[0036] 1. Extraction tube, 2. Bladder bag, 21. Bladder bag limit plate, 3. Grouting pipe, 31. Check valve, 32. Burst valve, 33. Plug, 4. Return grouting pipe, 41. Return grouting stop valve, 5. Drain pipe, 61. Borehole, 62. Borehole surrounding rock, 71. Grouting container, 72. Grouting pump, 73. Grouting stop valve, 74. Grouting pressure gauge, 81. Water pump, 82. Drainage stop valve, 83. Filter. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and beneficial effects of the present invention more clearly understood, the present invention is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings. Certain embodiments of the present invention will be described more comprehensively with reference to the accompanying drawings, in which some but not all embodiments will be shown. In fact, the various embodiments of the present invention can be implemented in many different forms and should not be construed as being limited to the embodiments described herein; rather, these embodiments are provided so that the present invention meets applicable legal requirements.

[0038] In the description of the present invention, it should be noted that the terms "inside", "outside", "upper", "lower", "front", "back" and the like indicate directions or positional relationships based on directions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0039] In the embodiment of the present invention, a downward water-containing gas extraction drilling hole sealing device and method are provided. Please refer to Figure 1 , Figure 2 shown.

[0040] A downward water-containing gas extraction borehole sealing device comprises an extraction pipe 1, a bag 2, a grouting pipe 3, a grouting supply end, a grouting return pipe 4, a drainage pipe 5 and a drainage end.

[0041] One end of the extraction pipe 1 extends into the downward water-containing gas extraction borehole 61, and the other end of the extraction pipe 1 can be connected to the extraction negative pressure pipeline. The gas in the downward water-containing gas extraction borehole 61 is extracted through the extraction pipe 1 and the extraction negative pressure pipeline.

[0042] Two bladder bags 2 are provided, and the two bladder bags 2 are arranged at a set distance along the axial direction of the extraction pipe 1. After the bladder bags 2 are expanded, they abut against the inner wall of the downward water-containing gas extraction borehole 61.

[0043] Bag limiting plates 21 are provided on both sides of the bag 2 on the extraction pipe 1, and the grouting pipe 3, the return grouting pipe 4 and the drainage pipe 5 are all fixedly connected to the bag limiting plates 21. One function of the bag limiting plates 21 is to guide and limit the expansion of the middle bag 2, so that the bag 2 expands radially, so that the bag 2 and the inner wall of the borehole 61 are more closely abutted. Another function of the bag limiting plates 21 is to fix the grouting pipe 3, the return grouting pipe 4 and the drainage pipe 5, so that the grouting pipe 3, the return grouting pipe 4 and the drainage pipe 5 can be extended into the borehole 61 together with the extraction pipe 1.

[0044] The grouting pipe 3 extends into the downward water-containing gas extraction borehole 61, and a plug 33 is provided at the end of the grouting pipe 3, which passes through the bag 2 and the space between the two bags 2. A check valve 31 is provided on the grouting pipe 3 located inside the bag 2, and a bursting valve 32 is provided on the grouting pipe 3 located in the space between the two bags 2. The bursting valve 32 is located above the outer side of the inner bag 2, so that the sealing slurry can quickly settle to the bottom of the sealing section (the space between the two bags 2), so that the sealing slurry can fully fill the sealing section and improve the sealing effect.

[0045] The check valve 31 is unidirectionally conducted from the grouting pipe 3 toward the inside of the bag 2 , allowing the sealing slurry to flow from the grouting pipe 3 into the bag 2 , but not allowing the sealing slurry in the bag 2 to flow back to the grouting pipe 3 .

[0046] The sealing slurry injection pressure in the grouting pipe 3 reaches the starting pressure P of the bursting valve 32. b When the bursting valve 32 is opened, and when the grouting pressure reaches the starting pressure P of the bursting valve 32 b When the bag 2 is inflated, the pressure of the bag 2 against the inner wall of the downward water-gas extraction borehole 61 reaches a set pressure value, so that the bag 2 fits tightly against the inner wall of the downward water-gas extraction borehole 61, thereby defining a closed space between the two inflated bags 2 and the borehole 61.

[0047] The grouting supply end is used to inject sealing slurry of set pressure into the grouting pipe 3.

[0048] The grouting supply end includes a grouting container 71, a grouting pump 72 and a grouting stop valve 73. The grouting container 71 contains sealing slurry. The grouting inlet of the grouting pump 72 is connected to the grouting container via a grouting inlet pipeline. The grouting outlet of the grouting pump 72 is connected to the grouting pipe 3 via a grouting outlet pipeline. The grouting stop valve 73 is provided on the grouting outlet pipeline. The grouting stop valve 73 is opened, the grouting pump 72 is started, and the sealing slurry in the grouting container 71 is injected into the grouting pipe 3 by the grouting pump 72. A grouting pressure gauge 74 is provided on the grouting outlet pipeline to monitor the grouting pressure of the sealing slurry in the grouting pipe 3 through the grouting pressure gauge 74.

[0049] The return slurry pipe 4 extends into the downward water-containing gas extraction borehole 61, passes through the outer bladder bag 2, and the end of the return slurry pipe 4 is located in the space between the two bladder bags 2. The return slurry pipe 4 is provided with a return slurry stop valve 41. The return slurry stop valve 41 is opened, and after the space between the two bladder bags 2 is filled with sealing slurry, the sealing slurry flows out from the return slurry pipe 4. Among them, the end of the return slurry pipe 4 is close to the outer bladder bag 2 and away from the inner bladder bag 2. When the sealing slurry flows out of the return slurry pipe 4, it can be more accurately judged that the space between the two bladder bags 2 is filled with sealing slurry.

[0050] One function of the return pipe 4 is that when the closed space is filled with sealing slurry, the sealing slurry flows out from the return pipe 4. Another function of the return pipe 4 is that when the drainage pipe 5 drains the water in the space between the two bladder bags 2 through the drainage end, the return pipe 4 is connected to the outside atmosphere to maintain the balance of air pressure inside and outside the closed space so that the water can be discharged normally.

[0051] The drainage pipe 5 extends into the downward water-gas extraction borehole 61 and passes through the outer bladder bag 2 . The end of the drainage pipe 5 is located in the space between the two bladder bags 2 .

[0052] The drainage end is used to discharge the water in the space between the two bladder bags 2 through the drainage pipe 5. The drainage end includes a water pump 81 and a drainage stop valve 82. The water inlet of the water pump 81 is connected to the drainage pipe 5, and the drainage stop valve 82 is set on the drainage pipe 5. Among them, the end of the drainage pipe 5 is close to the inner bladder bag 2 and away from the outer bladder bag 2 to drain the accumulated water in the closed space as much as possible. Open the return slurry stop valve 41, open the drainage stop valve 82, start the water pump 81, and the water in the space between the two bladder bags 2 is discharged through the drainage pipe 5. A filter net 83 is set at the end of the drainage pipe 5 to isolate large particles of impurities in the accumulated water in the closed space to avoid clogging the drainage pipe 5 and the water pump 81.

[0053] A method for sealing a downward water-containing gas extraction borehole is provided, using the downward water-containing gas extraction borehole sealing device described above in this embodiment, and the method comprises the following steps:

[0054] Step 1: Sealing preparation

[0055] After the downward water-containing gas extraction borehole 61 is formed, the extraction pipe 1, the bag 2, the grouting pipe 3, the return grouting pipe 4 and the drainage pipe 5 are extended into the downward water-containing gas extraction borehole 61, the grouting supply end is connected to the grouting pipe 3, and the drainage end is connected to the drainage pipe 5.

[0056] Step 2: "Two-blocking" construction

[0057] Open the grouting stop valve 73, start the grouting pump 72, and inject the sealing slurry into the bag 2 through the grouting pipe 3 and the check valve 31. When the grouting pressure gauge 74 reaches the starting pressure P of the bursting valve 32, b When the grouting pipe 3 is connected to the space between the two bags 2 through the bursting valve 32, the grouting stop valve 73 is closed, and the grouting pump 72 is stopped;

[0058] The starting pressure P of the burst valve 32 is set b , so that the grouting pressure gauge 74 reaches the starting pressure P of the bursting valve 32 b When the pressure of the bladder bag 2 is expanded and abutted against the inner wall of the downward water-gas extraction borehole 61, the pressure reaches the set pressure value, so that the bladder bag 2 is closely attached to the inner wall of the downward water-gas extraction borehole 61, and then the two expanded bladder bags 2 and the borehole 61 define a closed space.

[0059] Step 3: One row construction

[0060] The return slurry stop valve 41 is opened, the drainage stop valve 82 is opened, and the water pump 81 is started to discharge the water in the space between the two bladder bags 2 through the drainage pipe 5 .

[0061] Step 4: One-shot construction

[0062] Close the drainage stop valve 82, stop the water pump 81, reopen the grouting stop valve 73, restart the grouting pump 72, and inject the sealing slurry into the space between the two bags 2 through the grouting pipe 3 and the bursting valve 32; when the sealing slurry flows out of the return grouting pipe 4, it means that the space between the two bags 2 is filled with the sealing slurry. Close the return grouting stop valve 41, and when the grouting pressure gauge 74 reaches the set pressure range (0.5 to 2.0 MPa), allow the sealing slurry to penetrate into the cracks of the surrounding rock 62 of the borehole, close the grouting stop valve 73, and stop the grouting pump 72 to stop grouting.

[0063] So far, the present embodiment has been described in detail with reference to the accompanying drawings. Based on the above description, those skilled in the art should have a clear understanding of the downward water-containing gas extraction borehole sealing device and method of the present invention. The downward water-containing gas extraction borehole sealing device and method of the present invention adopts a new "two-blocking, one-draining, one-injection" method, first injecting sealing slurry into the bag 2 through the grouting pipe 3 to reach the starting pressure P of the bursting valve 32. b The bag 2 is expanded and the pressure against the inner wall of the borehole 61 reaches the set pressure value. A closed space is defined by the two expanded bags 2 and the borehole 61, and the grouting pipe 3 is connected to the closed space; the water in the closed space is then discharged through the drainage end through the drainage pipe 5; the sealing slurry is continued to be injected into the closed space through the grouting pipe 3. When the closed space is filled with the sealing slurry, when the grouting pressure gauge 74 reaches the set pressure range, the sealing slurry is infiltrated into the cracks of the borehole surrounding rock 62, so that the closed space and the cracks of the borehole surrounding rock 62 are fully filled with the sealing slurry, which greatly improves the sealing quality of the downward water-containing gas extraction borehole 61. The downward water-containing gas extraction borehole sealing device and method of the present invention fundamentally solves the problem of low sealing quality of the downward water-containing gas extraction borehole, and the device is simple, easy to construct and operate, low cost, and has high promotion and application value.

[0064] Of course, the specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A downward water-containing gas extraction borehole sealing device, characterized in that: include: The extraction pipe extends into the interior of the downward water-containing gas extraction borehole; The bladder bags are provided in two pieces and are arranged at a set distance along the axial direction of the extraction pipe, and abut against the inner wall of the downward water-gas extraction borehole after expansion; A grouting pipe extends into the downward water-containing gas extraction borehole, passes through the bag and the space between the two bags, a check valve is provided on the grouting pipe inside the bag, and a bursting valve is provided on the grouting pipe in the space between the two bags; A grouting supply end, used to inject sealing slurry of set pressure into the grouting pipe; A return slurry pipe extends into the downward water-bearing gas extraction borehole and passes through the outer bladder bag, and the end of the return slurry pipe is located in the space between the two bladder bags; A drainage pipe extends into the downward water-gas extraction borehole and passes through the outer bladder bag, with the end of the drainage pipe being located in the space between the two bladder bags; The drainage end is used to drain the water in the space between the two bladder bags through the drainage pipe.

2. A downward water-containing gas extraction drilling sealing device according to claim 1, characterized in that: The grouting supply end includes a grouting container, a grouting pump and a grouting stop valve. The grouting container contains sealed slurry. The grouting inlet of the grouting pump is connected to the grouting container via a grouting inlet pipeline. The grouting outlet of the grouting pump is connected to the grouting pipe via a grouting outlet pipeline. A grouting stop valve is arranged on the grouting outlet pipeline.

3. A downward water-containing gas extraction drilling sealing device according to claim 2, characterized in that: A grouting pressure gauge is arranged on the slurry outlet pipeline.

4. A downward water-containing gas extraction drilling sealing device according to claim 1, characterized in that: The drainage end comprises a water pump and a drainage stop valve. The water inlet of the water pump is connected to a drainage pipe, and the drainage stop valve is arranged on the drainage pipe.

5. A downward water-containing gas extraction drilling sealing device according to claim 1, characterized in that: The return slurry pipe is provided with a return slurry stop valve.

6. A downward water-containing gas extraction drilling sealing device according to claim 1, characterized in that: The bursting valve is located at an upper outer side of the inner bladder bag.

7. A downward water-containing gas extraction drilling sealing device according to claim 1, characterized in that: The end of the return slurry pipe is close to the outer bladder bag and far away from the inner bladder bag.

8. A downward water-containing gas extraction drilling sealing device according to claim 1, characterized in that: The end of the drain pipe is close to the inner bladder bag and away from the outer bladder bag.

9. A downward water-containing gas extraction drilling sealing device according to claim 1, characterized in that: Bag limiting plates are arranged on both sides of the bag on the extraction pipe, and the grouting pipe, the return grouting pipe and the drainage pipe are all fixedly connected to the bag limiting plates.

10. A method for sealing a downward water-containing gas extraction borehole, characterized in that: Using the downward water-containing gas extraction drilling sealing device according to any one of claims 1 to 9, the method comprises the following steps: Step 1: Sealing preparation After the downward water-containing gas extraction borehole is formed, the extraction pipe, the bag, the grouting pipe, the return grouting pipe and the drainage pipe are extended into the downward water-containing gas extraction borehole, the grouting supply end is connected to the grouting pipe, and the drainage end is connected to the drainage pipe; Step 2: "Two-blocking" construction Open the grouting stop valve, start the grouting pump, and inject the sealing slurry into the bag through the grouting pipe and the check valve. When the grouting pressure gauge reaches the starting pressure P of the bursting valve, b When the grouting is stopped, close the grouting stop valve and stop the grouting pump; Among them, the starting pressure P of the bursting valve is set b , so that the burst valve starting pressure P is expressed in the grouting pressure b When the bag expands and contacts the inner wall of the downward gas-bearing water extraction borehole, the pressure reaches the set pressure value; Step 3: "One row" construction Open the return slurry stop valve, open the drainage stop valve, start the water pump, and drain the water in the space between the two bags through the drainage pipe; Step 4: "One injection" construction Close the drainage stop valve, stop the water pump, reopen the grouting stop valve, restart the grouting pump, and inject the sealing slurry into the space between the two bags through the grouting pipe and the bursting valve; when the sealing slurry flows out of the return grouting pipe, close the return grouting stop valve, and when the grouting pressure gauge reaches the set pressure range, close the grouting stop valve and stop the grouting pump to stop grouting.

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