Pouch hole sealer, close-contact gas drainage borehole sealing method and device

Abstract

The present invention relates to a capsule hole sealer, a method and device for closely connecting gas drainage borehole sealing, belonging to the technical field of borehole sealing for gas drainage in coal mines. The capsule of the capsule hole sealer is an alkali-soluble capsule, which can automatically dissolve in an alkaline solution with a certain pH value; the sealing slurry is an alkali-modified sealing slurry, and its alkalinity increases as the water content decreases. When the sealing slurry gradually changes to a certain pH value, the capsule dissolves, and the sealing slurry directly contacts the borehole wall and hardens and consolidates to form a plug. In the present invention, the pressure-bearing capacity of the plug is several times higher than that of the plug formed by the fully wrapped capsule hole sealer, which not only ensures the sealing effect of the capsule sealing section, but also provides a basis for high-pressure grouting. Under the action of the grouting pressure, the sealing slurry can be injected into the borehole sealing section and the fissures around the hole, effectively ensuring the borehole plugging effect, improving the gas drainage efficiency, providing technical guarantee for the efficient drainage, safe production and effective utilization of gas in coal mines, and having high market promotion and application value.

Description

Technical Field

[0001] The invention belongs to the technical field of gas extraction drilling hole sealing in underground coal mines, and relates to a bag hole sealer, a close-contact gas extraction drilling hole sealing method and a device. Background Art

[0002] At present, gas disasters are still the most important factor restricting the safe production of coal mines. Efficient gas extraction is a fundamental measure to prevent and control coal mine gas disasters. Due to the advantages of simple construction and low cost, underground drilling has been widely used in coal mines. Efficient extraction requires that under the drainage effect of the extraction negative pressure, the gas in the coal body be extracted as quickly and as much as possible to ensure safe production during the recovery process, and the borehole and the extraction pipe be effectively sealed and connected to avoid leakage of the extraction negative pressure at the hole mouth, which makes it impossible to act on the entire hole section and achieve efficient extraction. It can be seen that the development of gas extraction drilling and sealing technology and process plays a very important role in the prevention and control of coal mine gas disasters and mine safety production.

[0003] At present, due to the high viscosity of polymer expansion materials and low strength after hardening, and the easy shrinkage of cement mortar after solidification, the sealing process is generally a two-blocking and one-injection pressure sealing process, that is, a plug is formed at both ends of the sealing section using a sealer, and then the sealing material is injected into the middle section. Since the hollow space is formed after the tunnel excavation and drilling construction, the ground stress will be redistributed, and there are relatively developed fracture channels near the drill hole mouth of the tunnel. Therefore, in order to ensure the sealing effect, it is necessary to press the sealing slurry into the fracture as much as possible under a certain pressure condition to seal it, reduce the leakage channel and improve the sealing effect. This requires that the pressure bearing capacity of the sealer acting as a plug is large enough.

[0004] There are two main types of hole sealers: capsule-type hole sealers and filter-type bag-type hole sealers. The capsule-type hole sealer is a hole sealer that is pressurized after the sealing material is injected into the hole sealer, which props up and expands the rubber shell of the hole sealer, and squeezes and seals the borehole wall under the action of pressure; the filter-type bag-type hole sealer filters the water in the sealing slurry, retains the dry material to form a plug, and realizes the pressure-bearing function. Due to the high cost of the capsule-type hole sealer, and the requirement that the coal cutter recovery cannot use iron hole sealing pipes, and the pressure-bearing capacity of the polyvinyl chloride pipe is limited, the buckling and sealing links are restricted and cannot withstand high pressure; the filter-type bag-type hole sealers are all cloth bags. Because they are located between the sealing material and the borehole wall, the direct hardening and consolidation of the sealing material and the coal rock mass is prevented, and the pressure-bearing capacity they provide is also very limited. Therefore, the current maximum pressure of pressurized grouting sealing is generally around 2 MPa. Judging from the sealing conditions of the boreholes exposed during mining, there is basically no sealing material in the cracks around the holes. This puts higher requirements on the sealing method. A sealing process that can provide higher grouting pressure is needed to improve the sealing and gas extraction effects. This also has important practical significance for the safe and efficient production of coal mines. Summary of the invention

[0005] In view of this, the purpose of the present application is to provide a pouch hole sealer, a close - type gas drainage borehole sealing method and device, so as to improve the pressure - bearing capacity of the plug.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A close - type gas drainage borehole sealing method uses a pouch hole sealer and an alkali - modified sealing slurry; the pouch of the pouch hole sealer is an alkali - soluble pouch, which can automatically dissolve in an alkaline solution with a certain pH value; as the water in the sealing slurry is lost, the alkalinity increases. When the sealing slurry gradually changes to a certain pH value, the pouch dissolves, and the sealing slurry comes into direct contact with the borehole wall and hardens and consolidates to form a plug.

[0008] Optionally, it includes the following steps:

[0009] S1 Fix the pouch hole sealer and the grouting pipe on the hole - sealing pipe according to the hole - sealing parameters, and send them to the predetermined position in the well.

[0010] S2 Inject the proportion - configured sealing slurry into the pouch hole sealer at both ends of the hole - sealing pipe through the grouting pump until the pouch hole sealer is filled with the sealing slurry. Keep grouting. The water in the sealing slurry in the pouch hole sealer is filtered out under extrusion. As the water is gradually filtered out, the sealing slurry in the pouch hole sealer becomes viscous and the pH value gradually increases. When it rises to a certain pH value, the pouch dissolves, and the sealing slurry comes into direct contact with the borehole wall and hardens and consolidates to form a plug.

[0011] S3 Keep grouting. After the pressure - bearing capacity of the plug reaches the rated pressure of the bursting valve, the bursting valve in the middle of the hole - sealing section opens, and the sealing slurry flows to the middle section of the hole - sealing. Wait until the middle section is filled with the sealing slurry. Under the action of high grouting pressure, the sealing slurry enters the cracks in the coal - rock mass around the borehole and hardens and consolidates, completing the sealing of the hole - sealing section and the air - leakage channels around the hole.

[0012] Optionally, the length of the pouch of the pouch hole sealer is 700 - 1000 mm, and it is composed of a non - dissolvable material with filterability at the end and an alkali - soluble material in the middle section.

[0013] Optionally, the non - dissolvable material with filterability at the end is high - strength flame - retardant and antistatic cotton linen, and the length is 150 - 250 mm.

[0014] Optionally, after the water filtration rate of the sealing slurry > 50%, the pH value > 8.5.

[0015] Optionally, when the sealing slurry is saturated with water, the pH value is 6.5 - 7.5.

[0016] Optionally, the viscosity of the sealing slurry > 12 cm.

[0017] A pouch hole sealer, comprising a pouch which includes an intermediate section and end heads located on the front and rear sides of the intermediate section. The material of the intermediate section is an alkali-soluble material, and the material of the end heads is an insoluble material with a filtering function.

[0018] A close-contact gas drainage borehole sealing device, comprising a sealing pipe, pouch hole sealers sleeved at both ends of the sealing pipe, and a grouting pipe penetrating through the pouch hole sealers. A slurry outlet is provided at the position of the grouting pipe corresponding to the pouch hole sealer, and a pressure blasting valve is provided at the middle position of the grouting pipe corresponding to the sealing pipe. The pouch hole sealer is the pouch hole sealer described above.

[0019] The beneficial effects of the present invention are as follows: By using the pouch hole sealer and the alkali-modified sealing slurry, the concentrated sealing slurry can directly contact the borehole wall and harden and consolidate to form a close-contact plug. The bearing capacity of this close-contact plug is several times higher than that of the plug formed by the fully enclosed pouch hole sealer, which not only ensures the sealing effect of the pouch sealing section but also provides a basis for high-pressure grouting. Under the action of the grouting pressure, the sealing slurry can be injected into the borehole sealing section and the cracks around the hole, effectively ensuring the borehole plugging effect, improving the gas drainage efficiency, providing technical guarantee for the efficient drainage, safe production and effective utilization of gas in coal mines, and having high market promotion and application value.

[0020] Other advantages, objectives and features of the present invention will be described to some extent in the subsequent description, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following description. Description of the Drawings

[0021] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be described in detail preferably with reference to the accompanying drawings, where:

[0022] Figure 1 It is the schematic diagram of the principle of the hole sealing method;

[0023] Figure 2 It is the structural schematic diagram of the hole sealer.

[0024] Reference numerals: sealing pipe 1, coal seam 2, cracks around the hole 3, grouting pipe 4, pouch hole sealer 5, gas drainage borehole 6, end head 7, intermediate section 8, blasting valve 9, grouting pipe plug 10. Detailed Embodiments

[0025] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand the other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the drawings provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner. Without conflict, the following embodiments and the features in the embodiments can be combined with each other.

[0026] Among them, the drawings are only for illustrative purposes, showing only schematic diagrams, not physical diagrams, and should not be construed as a limitation to the present invention; in order to better illustrate the embodiments of the present invention, some components in the drawings will be omitted, enlarged or reduced, which does not represent the size of the actual product; for those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0027] In the drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "rear", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings. This is 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 orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and should not be construed as a limitation to the present invention. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0028] Refer to Figures 1-2 , a method for sealing a closely-connected gas drainage borehole. A plug is formed through an alkali-soluble bag packer 5. After the sealing slurry enters the bag packer 5, the alkalinity increases as the moisture gradually filters out, dissolving the bag of the bag packer 5 to directly contact, harden, and consolidate with the borehole wall, greatly improving the pressure-bearing capacity, and thus ensuring the grouting pressure and the sealing effect. The specific steps are as follows:

[0029] S1: Lower the complete set of sealing devices to the predetermined position of the gas drainage borehole 6;

[0030] S2: Inject the prepared sealing slurry into the bag packer 5. The bag packer 5 filters out the moisture in the sealing slurry under the action of the grouting pressure. The sealing slurry becomes a paste, dissolves the alkali-soluble bag, and consolidates with the borehole wall to form an integral body, forming pressure-bearing plugs at both ends of the sealing section;

[0031] S3: After the plug bears pressure up to the rated pressure of the bursting valve 9, the bursting valve 9 opens to grout the hole-sealing section in the middle. After the hole-sealing slurry fills the hole-sealing section, under the action of high grouting pressure, it enters the cracks of the coal and rock mass around the borehole, completing the plugging of the hole-sealing section and the air leakage channels around the hole, and realizing efficient hole sealing.

[0032] The present invention forms a "plugging - grouting" hole - sealing process by combining the alkali - soluble bag hole - sealer 5 with the alkali - denatured hole - sealing material, greatly enhancing the pressure - bearing capacity of the plug in the hole - sealing section, enabling the hole - sealing material to be in close contact with the borehole wall throughout the entire hole - sealing section, and thus increasing the grouting pressure in the hole - sealing section.

[0033] Optionally, the length of the bag of the bag hole - sealer 5 is 700 - 1000 mm, which is composed of the filterable insoluble material forming the end 7 and the alkali - soluble material forming the middle section 8; the filterable insoluble material forming the end 7 can be high - strength flame - retardant and antistatic cotton linen cloth, meeting the requirements for use in coal mines, with a length of 150 - 250 mm; the alkali - soluble material forming the middle section 8 can be optionally polyester filter cloth; the hole - sealing slurry is nearly neutral when saturated with water, with a pH value of 6.5 - 7.5, and its viscosity measured by the falling - hammer method is > 12 cm, having good fluidity and being able to flow in the tiny crack channels to fill the cracks 3 around the hole; after the water loss rate of the hole - sealing slurry > 50%, the pH value > 8.5, and the alkali - soluble material located in the middle section 8 of the bag will dissolve rapidly in an environment with a pH value > 8.5.

[0034] After the hole - sealing slurry enters the bag hole - sealer 5, it quickly fills the bag, and under the action of the grouting pressure, the cotton linen cloth at the end 7 of the bag filters out the water in the hole - sealing slurry; after the water loss rate of the hole - sealing slurry > 50% and the pH value > 8.5, the alkali - soluble material of the bag is dissolved. After the alkali - soluble material of the bag is dissolved, the concentrated paste - like hole - sealing slurry comes into direct contact with the borehole wall. During the continuous grouting process of the grouting pump, the pressure in the bag increases, causing continuous water loss and accelerating the hardening of the hole - sealing slurry in the bag. After the alkali - soluble material of the bag is dissolved, the end 7 provides the initial pressure - bearing capacity and is squeezed by the hole - sealing solution in the bag and the borehole wall. After the hole - sealing solution in the bag and the borehole wall are consolidated and solidified, they provide a higher later pressure - bearing capacity. The bursting valve 9 opens to grout the middle hole - sealing section, and under the action of high grouting pressure, the hole - sealing slurry fills the middle hole - sealing section and enters the cracks 3 around the hole, realizing efficient hole sealing.

[0035] The hole - sealing slurry is prepared from water and alkaline dry powder in a mass ratio of 0.7 - 0.8:1. The mass ratio of the alkaline dry powder can be: 70 - 80% cement, 8 - 10% bentonite, 5 - 8% gypsum, 5 - 8% silicon dioxide, 2 - 3% sodium dodecyl sulfonate, 1 - 2% sodium carbonate, 1 - 2% sodium meta - aluminate, and 0.5 - 1% quicklime.

[0036] The pocket hole sealer 5 includes a pocket, which includes an intermediate section 8 and end heads 7 on both the front and back sides of the intermediate section 8. The material of the intermediate section 8 is an alkali-soluble material, and the material of the end heads 7 is an insoluble material with a filtering function.

[0037] The close-contact type gas drainage borehole sealing device includes a sealing pipe 1, pocket hole sealers 5 sleeved on both ends of the sealing pipe 1, and a grouting pipe 4 passing through the pocket hole sealers 5. The grouting pipe 4 is provided with a slurry outlet corresponding to the position of the pocket hole sealer 5, a pressure blasting valve 9 is provided at the middle position of the grouting pipe 4 corresponding to the sealing pipe 1, a plug 10 is provided at the end of the grouting pipe 4, and the pocket hole sealer 5 is the pocket hole sealer 5 described above.

[0038] The present invention uses a sealing material with a nearly neutral pH value when saturated with water. As the water content decreases, the pH value of the material increases, and the pH value > 8.5 after the slurry water filtration rate exceeds 50%. The present invention also uses a pocket hole sealer 5 composed of an alkali-soluble material and high-strength cotton linen cloth as a plug. The cotton linen cloth at both ends of the pocket filters the water in the sealing slurry, promotes the pressure rise of the pocket and provides preliminary pressure-bearing capacity. When the pH value of the slurry environment in the pocket reaches the dissolution threshold of the alkali-soluble material, the intermediate section 8 of the pocket dissolves, enabling the slurry material to come into direct close contact with the borehole wall. Under the action of the grouting pressure, the hardening of the sealing material in the pocket is accelerated and consolidated with the borehole wall to form a close-contact type plug to provide the final pressure-bearing capacity. The pressure-bearing capacity of the close-contact type plug is several times higher than that of the plug formed by the fully wrapped pocket hole sealer, which not only ensures the sealing effect of the pocket sealing section but also provides a basis for high-pressure grouting, realizing the injection of the sealing slurry into the borehole sealing section and the surrounding fissures 3 of the hole under the action of the grouting pressure. Through the combined action of the pocket sealing section, the grouting sealing section and the surrounding fissures 3 of the hole, the present invention can effectively ensure the borehole plugging effect, improve the gas drainage efficiency, provide technical support for the efficient drainage, safe production and effective utilization of gas in coal mines, and has high on-site popularization and application value.

[0039] Example 1

[0040] The gas content of coal seam 2 in a certain coal mine is relatively high and the permeability is relatively good. The coal mine uses bagged polymer materials for hole sealing, but the gas drainage concentration and purity are relatively low, and the overall gas drainage effect is relatively poor. In order to improve the gas drainage effect, the close-contact type sealing method of the present invention is used for operation.

[0041] Step 1: Use a pocket hole sealer 5 with a total length of 830 mm and end heads of 180 mm. Connect the grouting pipe 4 and the sealing pipe 1 according to the determined sealing depth and length, and lower the pocket hole sealer 5 to the designated position.

[0042] Step 2: Prepare the hole-sealing slurry in proportion, inject it into the bladder hole-sealer 5 through the grouting pipe 4 using a grouting pump until it is full. After continuous grouting, the water in the hole-sealing slurry inside the bladder is squeezed out, the pH value of the hole-sealing slurry inside the bladder increases and dissolves the alkali-soluble material section, and the material comes into direct contact with the borehole wall and hardens and consolidates.

[0043] Step 3: When the pressure of the plug reaches 6 MPa, the blasting valve 9 opens and starts grouting into the middle hole-sealing section. When the grouting pressure in the middle hole-sealing section reaches 6 MPa and can maintain the pressure for 10 minutes, the grouting is completed.

[0044] In this embodiment, in the working face of this mine, 89 and 93 boreholes were plugged respectively using bagged polymer materials and the close-hole-sealing method of the present invention. The same gas drainage conditions were used for all boreholes for connection and drainage, and the gas drainage concentration and pure drainage volume of the boreholes were measured every 2 days within a 3-month inspection period. The average gas drainage concentration of the boreholes plugged with bagged polymer materials in the first month was 49%, the average gas drainage concentration during the inspection period was 29%, and the pure drainage volume was 0.72 m 3 / min; the average gas drainage concentration of the boreholes using the close-hole-sealing method in the first month was 56%, the average gas drainage concentration during the inspection period was 47%, and the pure drainage volume was 1.06 m 3 / min. It can be seen from the gas drainage results that compared with the high-viscosity polymer materials that only plug the hole-sealing section of the borehole, since the close-hole-sealing method can provide a higher pressure-bearing capacity, high-pressure slurry materials are filled in the bladder hole-sealing section, the middle hole-sealing section, and the borehole wall fissure 3, effectively improving the hole-sealing effect.

[0045] Example 2

[0046] In a certain mine, the cross-section of the roadway excavation is large. In order to improve the gas drainage effect, large-diameter boreholes are generally constructed for drainage, resulting in relatively developed borehole wall fissures 3. The two-block-one-injection hole-sealing process is used to plug the boreholes, but the gas drainage compliance time is relatively long, causing tension in the connection between gas drainage, excavation, and mining in the mine, and affecting the safe and efficient production of the mine. To solve the problems of gas drainage and treatment in the mine, the close-hole-sealing method of the present invention is used for operation.

[0047] Step 1: Use a bladder hole-sealer 5 with a total length of 950 mm and a head of 230 mm. Fix the bladder hole-sealer 5 and the grouting pipe 4 on the hole-sealing pipe 1 according to the hole-sealing parameters and send them into the borehole.

[0048] Step 2: Prepare the hole-sealing slurry, inject the hole-sealing slurry into the bladder of the bladder hole-sealer 5 through a grouting pump. Under the filtering action of the cotton linen cloth at the end of the bladder, the pH value of the hole-sealing slurry inside the bladder rises above 8.5, the alkali-soluble bladder dissolves, the grouting pressure continues to increase, accelerating the solidification of the hole-sealing slurry inside the bladder, and forming a whole with the borehole wall.

[0049] Step 3: After the pressure in the bladder reaches 7 MPa, the blasting valve 9 automatically opens and starts grouting into the middle hole-sealing section and the surrounding cracks 3 of the hole. When the grouting pressure in the middle hole-sealing section reaches 8 MPa and can maintain the pressure for 15 minutes, the grouting is completed.

[0050] In Step 3 of this embodiment, when the bladder pressure reaches 7 MPa and the grouting pressure in the middle hole-sealing section can reach 8 MPa, it is because during the normal pressure and the process when the pressure in the middle hole-sealing section does not reach 7 MPa, the material of the hole-sealing section of the bladder continues to harden, and the bearing capacity of the end 7 is further improved, enabling pressure grouting hole-sealing at 8 MPa.

[0051] In this embodiment, in the application working face of this mine, both the traditional fully wrapped bladder hole-sealing device and the close-contact hole-sealing method of the present invention have completed the plugging of 70 boreholes. The same drainage conditions are used for all boreholes for connection and drainage, and the drainage concentration and drainage pure quantity of the boreholes are measured twice a week within a 5-month investigation period. Compared with the boreholes using the fully wrapped bladder hole-sealing device, the gas drainage concentration and drainage pure quantity of the boreholes using the close-contact hole-sealing method have increased by 63% and 51% respectively. Moreover, during the coal face mining process, the exposed drainage boreholes 6 are observed, and it is found that some fully wrapped bladder hole-sealing devices can be pulled out from the holes, and there is basically no hole-sealing material in the surrounding cracks 3 of the holes. However, for the boreholes using the close-contact hole-sealing process, the materials in the hole-sealing section and the surrounding cracks 3 of the holes are bonded and hardened with the coal and rock mass to form a whole, and there is no air leakage channel in the hole-sealing section.

[0052] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the present technical solution, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A method for sealing a close - type gas drainage borehole, characterized in that: Use a bladder packer and an alkaline denaturation sealing slurry; the bladder of the bladder packer is an alkali-soluble bladder that can automatically dissolve in an alkaline solution with a certain pH value; as the water in the sealing slurry is lost, the alkalinity increases. When the sealing slurry gradually changes to a certain pH value, the bladder dissolves, and the sealing slurry comes into direct contact with the borehole wall and hardens and consolidates to form a plug; the bladder is composed of a non-dissolvable material with filterability at the ends and an alkali-soluble material in the middle section.

2. The close-type gas drainage borehole sealing method according to claim 1, characterized in that: It includes the following steps: S1 Fix the bladder packer and the grouting pipe on the sealing pipe according to the sealing parameters and send them to the predetermined position in the well. S2 Inject the prepared sealing slurry in proportion into the bladder packers at both ends of the sealing pipe through the grouting pump until the bladder packers are filled with the sealing slurry. Keep grouting. The water in the sealing slurry in the bladder packer is filtered out due to extrusion. As the water is gradually filtered out, the sealing slurry in the bladder packer becomes viscous and the pH value gradually increases. When it rises to a certain pH value, the bladder dissolves, and the sealing slurry comes into direct contact with the borehole wall and hardens and consolidates to form a plug. S3 Keep grouting. After the pressure on the plug reaches the rated pressure of the blasting valve, the blasting valve in the middle of the sealing section opens, and the sealing slurry flows to the middle section of the sealing. When the middle section is filled with the sealing slurry, under the action of high grouting pressure, the sealing slurry enters the cracks in the coal and rock mass around the borehole and hardens and consolidates to complete the sealing of the sealing section and the air leakage channels around the hole.

3. The close-type gas drainage borehole sealing method according to claim 1, characterized in that: The length of the bladder of the bladder packer is 700 - 1000 mm.

4. A close - type gas drainage borehole sealing method according to claim 3, characterized in that: The non-dissolvable material with filterability at the ends is high-strength flame-retardant and antistatic cotton linen cloth with a length of 150 - 250 mm.

5. A method for sealing a close-coupled gas drainage borehole according to claim 1, characterized in that: After the water loss rate of the sealing slurry is > 50%, the pH value > 8.

5.

6. The close - type gas drainage borehole sealing method according to claim 1, characterized in that: When the sealing slurry is saturated with water, the pH value is 6.5 - 7.5.

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