Dynamic sealing system and method for extraction drill hole

Abstract

The invention discloses an extraction drill hole dynamic sealing system and method, and belongs to the field of coal mine gas extraction. A grouting subsystem is arranged in each extraction drill hole, and each grouting subsystem is provided with a grouting branch pipe, a first electromagnetic valve, a pressure release valve, a low-pressure one-way valve, a high-pressure one-way valve and a bag; the extraction subsystem is provided with an extraction pipe, a concentration sensor, a pressure gauge and a second electromagnetic valve; low-pressure grout is injected into the bag through the two low-pressure one-way valves to achieve two-blocking, and after pressurization, the sealed cavity is filled with grout through the high-pressure one-way valves to achieve one-filling; and all the grouting subsystems are communicated with the grouting mechanism through a grouting header pipe. The first electromagnetic valve, the pressure release valve, the concentration sensor, the pressure gauge and the second electromagnetic valve can intelligently control the injection amount of slurry in the sealing cavity in a linkage mode, and long-term dynamic stable sealing is achieved when an extraction drill hole fails for multiple times; and a pulse grouting pump in the grouting mechanism achieves intermittent pulse grouting by receiving pulse signals, and the hole sealing quality and stability can be effectively improved.

Description

Technical Field

[0001] The present application relates to the technical field of coal mine gas extraction, and in particular to a dynamic sealing system and method for extraction boreholes. Background Art

[0002] As my country's coal resources gradually move towards the stage of deep mining, the "three highs and one low" nature of coal seams has become increasingly obvious. Due to the low strength of the coal rock mass around the high-gas, low-permeability and soft coal seams, there are often microcracks around the drilling and sealing sections. These microcracks will become channels for gas leakage. The negative pressure of extraction will produce significant losses when it is transmitted to the coal seam, making it difficult to effectively extract the gas, which will directly affect the extraction efficiency. In addition, the presence of microcracks will change the physical structure of the coal seam, reduce the permeability of the coal seam, increase the flow resistance of gas in the coal seam, and increase the difficulty of extraction. Due to the presence of microcracks, gas is easily leaked into the surrounding environment during the extraction process, resulting in a decrease in the concentration of extracted gas. Low concentrations of gas not only reduce the extraction efficiency, but also increase the cost and difficulty of subsequent treatment.

[0003] Furthermore, in the process of deep mining, factors such as mining disturbance, tunnel excavation, periodic roof pressure and blasting vibration will interfere with the boreholes in the coal seam where gas is being extracted. This interference will further reduce the strength of the coal body around the gas extraction borehole, weaken its compressive capacity, and easily undergo plastic deformation after being compressed, resulting in a large number of conductive microcracks in the coal rock around the borehole. The conductive microcracks in the borehole and the surrounding area will then further evolve into new microcracks, causing the sealing section to loosen, directly affecting the sealing performance and extraction efficiency of the borehole. Even if the ideal extraction effect can be achieved in the early stage of gas extraction, as these disturbances continue to intensify, the sealing of the borehole and the subsequent extraction results will also be gradually adversely affected.

[0004] At present, the traditional grouting technology and methods can only play a certain role in sealing the micro cracks around the borehole and the borehole, but cannot play a role in sealing the new cracks derived from the influence of subsequent factors. At the same time, the traditional solid sealing material cannot deform with the force of the borehole, which can easily cause the borehole sealing failure.

[0005] The existing secondary plugging system and method for improving the gas extraction effect of boreholes proposes secondary plugging and sealing. Due to the complex and changeable geological conditions of coal seams, this method can only plug the failed borehole once, and cannot achieve long-term dynamic and stable plugging when subsequent extraction boreholes fail multiple times. After determining that the seal fails in the borehole, it is necessary to manually control the liquid separation regulator to connect the pump liquid pipeline with the injection pipe in the failed borehole, and the degree of intelligence is low. Summary of the invention

[0006] The embodiments of the present application provide a dynamic sealing system and method for extraction boreholes, which can solve the problems that the existing methods cannot achieve long-term dynamic and stable sealing when subsequent extraction boreholes fail multiple times and have a low degree of intelligence.

[0007] In order to achieve the above object, the technical solution of the embodiment of the present invention is:

[0008] In a first aspect, an embodiment of the present invention provides a dynamic sealing system for a drainage borehole, including a control mechanism, a grouting mechanism, a grouting main pipe, a grouting subsystem, and a drainage subsystem;

[0009] The grouting subsystem includes a grouting branch pipe, a first solenoid valve, a pressure relief valve, a low-pressure one-way valve, a high-pressure one-way valve and a bladder;

[0010] The first solenoid valve, the pressure relief valve, the low-pressure one-way valve, the high-pressure one-way valve and the low-pressure one-way valve are sequentially arranged on the grouting branch pipe;

[0011] A bag is respectively arranged at the position of the two low-pressure one-way valves on the grouting branch pipe, and the low-pressure one-way valve is connected to the grouting branch pipe and the bag;

[0012] A grouting branch pipe is arranged in one of the extraction boreholes, so that the two bags arranged on the grouting branch pipe are arranged in the extraction borehole, and a sealed cavity is formed between the two bags filled with slurry, and the sealed cavity is located between the elastic area and the original stress area in the stress concentration area of ​​the extraction borehole, and the high-pressure one-way valve is located in the sealed cavity and connects the grouting branch pipe and the sealed cavity;

[0013] One end of all the grouting branch pipes is connected to one end of the grouting main pipe;

[0014] The other end of the grouting main pipe is connected to the grouting mechanism;

[0015] The extraction subsystem includes an extraction branch pipe, a concentration sensor, a pressure gauge and a second solenoid valve;

[0016] The concentration sensor, the pressure gauge and the second solenoid valve are arranged on the extraction branch pipe;

[0017] One end of one of the extraction branch pipes extends into one of the extraction boreholes, and the other ends of all the extraction branch pipes are connected to one end of the extraction main pipe;

[0018] The first solenoid valve, the pressure relief valve, the low-pressure one-way valve, the high-pressure one-way valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the control mechanism.

[0019] In combination with the first aspect, in a possible implementation manner, the slurry is a low-viscosity sealing slurry.

[0020] In combination with the first aspect, in a possible implementation, the control mechanism includes a monitoring substation, an editable logic controller, and a ground monitoring platform;

[0021] The first solenoid valve, the pressure relief valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the monitoring substation;

[0022] The monitoring substation is electrically connected to the editable logic controller;

[0023] The editable logic controller is electrically connected to the ground monitoring platform.

[0024] In combination with the first aspect, in a possible implementation, the extraction borehole dynamic sealing system further includes an explosion-proof power supply;

[0025] The monitoring substation is electrically connected to the explosion-proof power supply;

[0026] The explosion-proof power supply is electrically connected to the editable logic controller.

[0027] In a second aspect, an embodiment of the present invention provides a method for dynamically sealing a drainage borehole, based on the above-mentioned dynamic sealing system for drainage boreholes, comprising:

[0028] A first solenoid valve, a pressure relief valve, a low-pressure one-way valve, a high-pressure one-way valve and a low-pressure one-way valve are sequentially arranged on the grouting branch pipe; a bag is respectively arranged at the position where the two low-pressure one-way valves are located on the grouting branch pipe, and the low-pressure one-way valve is connected to the grouting branch pipe and the bag;

[0029] A grouting branch pipe is arranged in a drainage borehole, so that the two bags arranged on the grouting branch pipe are arranged in the drainage borehole, and a sealed cavity is formed between the two bags filled with slurry, and the sealed cavity is located between the elastic area and the original stress area in the stress concentration area of ​​the drainage borehole, and the high-pressure one-way valve is located in the sealed cavity and connects the grouting branch pipe and the sealed cavity;

[0030] One end of all the grouting branch pipes is connected to one end of the grouting main pipe; the other end of the grouting main pipe is connected to the grouting mechanism;

[0031] The concentration sensor, the pressure gauge and the second electromagnetic valve are arranged on the extraction branch pipe; one end of the extraction branch pipe extends into an extraction borehole, and the other ends of all the extraction branch pipes are connected to one end of the extraction main pipe;

[0032] The first solenoid valve, the pressure relief valve, the low-pressure one-way valve, the high-pressure one-way valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the control mechanism;

[0033] The control mechanism controls the grouting mechanism, the first solenoid valve and the two low-pressure one-way valves to open, and injects slurry into the bags arranged at the positions of the two low-pressure one-way valves on each grouting branch pipe through the grouting main pipe and the grouting branch pipe until a sealed cavity is formed between the two bags filled with slurry, and then the control mechanism controls the high-pressure one-way valve to open, so that the sealed cavity is filled with slurry, and then the control mechanism controls the first solenoid valve to close and the second solenoid valve to open, and gas extraction operation starts;

[0034] The dynamic sealing step is then performed multiple times, and the dynamic sealing step includes: the concentration sensor monitors the gas extraction concentration value of the extraction branch pipe, and transmits the gas extraction concentration value to the control mechanism; when the gas extraction concentration value is less than the preset concentration value, the control mechanism controls the second solenoid valve to close for a first preset time; if the control mechanism monitors that the pressure of the pressure gauge within the first preset time is less than the preset pressure value, the control mechanism controls the first solenoid valve to open, and controls the grouting mechanism to intermittently grout until the control mechanism monitors that the grouting pressure reaches the upper limit pressure of the pressure relief valve, and the control mechanism controls the first solenoid valve to close, and the second solenoid valve to open, and the gas extraction operation continues.

[0035] In combination with the second aspect, in a possible implementation, the slurry is a low-viscosity sealing slurry.

[0036] In combination with the second aspect, in a possible implementation, the first solenoid valve, the pressure relief valve, the low-pressure one-way valve, the high-pressure one-way valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to a control mechanism, including:

[0037] The first solenoid valve, the pressure relief valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the monitoring substation;

[0038] Electrically connect the monitoring substation and the editable logic controller;

[0039] The editable logic controller is electrically connected to the ground monitoring platform.

[0040] In conjunction with the second aspect, in a possible implementation, the extraction borehole dynamic sealing method further includes: electrically connecting the monitoring substation to an explosion-proof power supply;

[0041] The explosion-proof power supply is electrically connected to the editable logic controller.

[0042] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0043] The dynamic sealing system for the extraction borehole provided in the embodiment of the present invention forms a sealing cavity between two bags, and the sealing cavity is filled with slurry. The dynamic sealing effect of the extraction borehole is judged by the linkage control between the concentration sensor and the pressure gauge, and the monitoring data is transmitted to the control mechanism, and the control mechanism controls the operation of the grouting mechanism according to the monitoring data. The first solenoid valve, the pressure relief valve, the concentration sensor, the pressure gauge, and the second solenoid valve can be intelligently linked to control the injection amount of the slurry in the sealing cavity to achieve dynamic sealing of the extraction borehole. When the dynamic sealing of the extraction borehole fails, the extraction borehole can be quickly sealed without a limit on the number of times, and long-term dynamic stable sealing can be achieved when the extraction borehole fails multiple times. In addition, the first solenoid valve, the pressure relief valve, the concentration sensor, the pressure gauge, and the second solenoid valve in the embodiment of the present application are intelligently linked and controlled by the control mechanism, and the degree of intelligence is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0045] Figure 1 A schematic diagram of the structure of a dynamic sealing system for a drainage borehole provided in an embodiment of the present application;

[0046] Figure 2 A partial schematic diagram of the dynamic sealing system for extraction drilling provided in the embodiment of the present application Figure 1 ;

[0047] Figure 3 A partial schematic diagram of the dynamic sealing system for extraction drilling provided in the embodiment of the present application Figure 2 ;

[0048] Figure 4 A partial schematic diagram of the dynamic sealing system for extraction drilling provided in the embodiment of the present application Figure 3 ;

[0049] Figure 5 A partial schematic diagram of the dynamic sealing system for extraction drilling provided in the embodiment of the present application Figure 4 .

[0050] Icons: 1- grouting branch pipe; 2- grouting main pipe; 3- first solenoid valve; 4- pressure relief valve; 5- low-pressure one-way valve; 6- high-pressure one-way valve; 7- bag; 8- concentration sensor; 9- pressure gauge; 10- second solenoid valve; 20- grouting mechanism; 201- grouting cylinder; 202- pulse grouting pump; 30- control mechanism; 301- monitoring substation; 302- editable logic controller; 303- ground monitoring platform; 40- explosion-proof power supply; 50- extraction branch pipe; 60- extraction main pipe; 70- automatic water drainer; 80- gas extraction pump; A- sealed chamber; B- coal seam; C- extraction borehole. DETAILED DESCRIPTION

[0051] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0052] In the description of the embodiments of the present invention, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, rather than indicating or implying that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limitations on the present invention. The terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. In addition, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to the specific circumstances.

[0053] Please refer to Figure 1 As shown, an embodiment of the present invention provides a dynamic sealing system for a drainage borehole, including a control mechanism 30, a grouting mechanism 20, a grouting main pipe 2, a grouting subsystem and a drainage subsystem;

[0054] The grouting subsystem includes a grouting branch pipe 1 , a first solenoid valve 3 , a pressure relief valve 4 , a low-pressure one-way valve 5 , a high-pressure one-way valve 6 and a bladder 7 .

[0055] like Figures 1 to 5As shown, the first solenoid valve 3, the pressure relief valve 4, the low-pressure one-way valve 5, the high-pressure one-way valve 6 and the low-pressure one-way valve 5 are sequentially arranged on the grouting branch pipe 1.

[0056] A bag 7 is respectively arranged at the position of the two low-pressure one-way valves 5 on the grouting branch pipe 1 , and the low-pressure one-way valve 5 connects the grouting branch pipe 1 and the bag 7 .

[0057] like Figures 2 to 5 As shown, a grouting branch pipe 1 is arranged in a drainage borehole C, and two bags 7 arranged on the grouting branch pipe 1 are arranged in the drainage borehole C, and a sealed cavity A is formed between the two bags 7 after being filled with slurry, as shown in FIG. Figure 2 As shown, the sealing cavity A is located between the elastic area and the original stress area in the stress concentration area of ​​the extraction borehole C, and the high-pressure one-way valve 6 is located in the sealing cavity A and connects the grouting branch pipe 1 and the sealing cavity A.

[0058] like Figure 1 As shown, one end of all grouting branch pipes 1 is connected to one end of the grouting main pipe 2. The other end of the grouting main pipe 2 is connected to the grouting mechanism 20. That is, all grouting subsystems are connected to the grouting mechanism 20 through the grouting main pipe 2.

[0059] The extraction subsystem includes an extraction branch pipe 50 , a concentration sensor 8 , a pressure gauge 9 and a second solenoid valve 10 . The concentration sensor 8 , the pressure gauge 9 and the second solenoid valve 10 are arranged on the extraction branch pipe 50 .

[0060] One end of a drainage branch pipe 50 extends into a drainage borehole C, and the other ends of all the drainage branch pipes 50 are connected to one end of the drainage main pipe 60. The other end of the drainage main pipe 60 is connected to the automatic water discharger 70, and the automatic water discharger 70 is connected to the gas drainage pump 80. That is, one set of grouting subsystem and one set of drainage subsystem are set in one drainage borehole C.

[0061] The first solenoid valve 3, the pressure relief valve 4, the low-pressure check valve 5, the high-pressure check valve 6, the concentration sensor 8, the pressure gauge 9, the second solenoid valve 10, and the grouting mechanism 20 are all electrically connected to the control mechanism 30. The pressure gauge 9 may be an intelligent digital pressure gauge.

[0062] The grouting mechanism 20 includes a grouting cylinder 201 and a pulse grouting pump 202. The grouting cylinder 201 is connected to the pulse grouting pump 202, and the pulse grouting pump 202 is connected to the other end of the grouting main pipe 2. The grouting cylinder 201 and the pulse grouting pump 202 are both electrically connected to the control mechanism 30.

[0063] In the actual operation of the dynamic sealing system for the extraction borehole provided by the embodiment of the present invention, firstly, the first solenoid valve 3, the pressure relief valve 4, the low-pressure one-way valve 5, the high-pressure one-way valve 6 and the low-pressure one-way valve 5 are sequentially arranged on the grouting branch pipe 1. A bag 7 is respectively arranged at the position of the two low-pressure one-way valves 5 on the grouting branch pipe 1, and the low-pressure one-way valve 5 connects the grouting branch pipe 1 and the bag 7. Then, a grouting branch pipe 1 is arranged in an extraction borehole C, so that the two bags 7 arranged on the grouting branch pipe 1 are arranged in the extraction borehole C, and a sealed cavity A is formed between the two bags 7 after being filled with slurry, and the sealed cavity A is located between the elastic area and the original stress area in the stress concentration area of ​​the extraction borehole C, and the high-pressure one-way valve 6 is located in the sealed cavity A and connects the grouting branch pipe 1 and the sealed cavity A. The low-pressure one-way valve 5 and the high-pressure one-way valve 6 are one-way valves that can prevent the slurry from flowing back.

[0064] Then one end of all grouting branch pipes 1 is connected to one end of grouting main pipe 2. The other end of grouting main pipe 2 is connected to grouting mechanism 20.

[0065] Then, the concentration sensor 8, the pressure gauge 9 and the second electromagnetic valve 10 are arranged on the extraction branch pipe 50. One end of an extraction branch pipe 50 extends into an extraction borehole C, and the other ends of all the extraction branch pipes 50 are connected to one end of the extraction main pipe 60.

[0066] Finally, the first solenoid valve 3, the pressure relief valve 4, the low-pressure one-way valve 5, the high-pressure one-way valve 6, the concentration sensor 8, the pressure gauge 9, the second solenoid valve 10, and the grouting mechanism 20 are all electrically connected to the control mechanism 30 to complete the installation of the extraction borehole dynamic sealing system.

[0067] When performing the "two blocking and one injection" operation, the control mechanism 30 controls the grouting mechanism 20, the first solenoid valve 3 and the two low-pressure one-way valves 5 to open, and injects low-pressure slurry into the bag 7 set at the position of the two low-pressure one-way valves 5 on each grouting branch pipe 1 through the grouting main pipe 2 and the grouting branch pipe 1 until the two bags 7 are filled with slurry to form a sealed cavity A, and the low-pressure slurry is injected into the bag 7 through the two low-pressure one-way valves 5 to achieve two blocking. After that, the control mechanism 30 controls the high-pressure one-way valve 6 to open, so that the sealed cavity A is filled with slurry, thereby forming a sealing section, that is, after pressurization, the sealing cavity A is filled with slurry through the high-pressure one-way valve 6 to achieve one injection. The "two blocking and one injection" sealing method is adopted to arrange the sealing section of the extraction borehole C between the elastic zone and the original stress zone in the stress concentration zone, and the two bags 7 realize the blocking of the sealed cavity A, and the two bags 7 and the sealing section jointly realize the blocking of the extraction borehole C. Then, the control mechanism 30 controls the first solenoid valve 3 to close and the second solenoid valve 10 to open, and the gas extraction operation starts.

[0068] In practice, in the extraction drilling site, affected by the action of mining, micro cracks are generated around the sealing section formed by the sealing cavity A of the extraction borehole C filled with slurry, resulting in air leakage when the sealing of the extraction borehole C fails, which in turn leads to a decrease in the extraction concentration.

[0069] At this time, the dynamic sealing step is performed multiple times, and the dynamic sealing step includes: the concentration sensor 8 monitors the gas extraction concentration value of the extraction branch pipe 50, and transmits the gas extraction concentration value to the control mechanism 30. When the gas extraction concentration value is less than the preset concentration value (such as the preset concentration value can be 50% of the normal extraction concentration value, and the specific value of the preset concentration value can be set according to the difference in extraction parameters of each coal mine working face. When the gas extraction concentration value is less than the preset concentration value, the sealing effect of the extraction borehole C becomes worse), the control mechanism 30 controls the second solenoid valve 10 to close for a first preset time (such as the first preset time can be 30 minutes). If the control mechanism 30 monitors that the pressure of the pressure gauge 9 within the first preset time is less than the preset pressure value (that is, the pressure value displayed by the pressure gauge 9 remains unchanged or increases slowly, it proves that the seal of the extraction borehole C has failed; if the pressure of the pressure gauge 9 continues to rise, it proves that the sealing of the extraction borehole C is intact), the control mechanism 30 controls the first solenoid valve 3 to open, and controls the grouting mechanism 20 to perform intermittent grouting (the control mechanism 30 transmits the pulse signal to the grouting mechanism 20, thereby realizing the intermittent pulse grouting of the grouting mechanism 20. Compared with the ordinary equal pressure grouting process, the intermittent pulse grouting forms more seepage channels, and forms a relatively stable "network skeleton" composed of multiple seepage channels around the sealing section, which can effectively improve the sealing quality and stability. In addition, the intermittent pulse grouting enables the grouting slurry to be more effectively injected into the sealing cavity A under the intermittent action of the grouting pressure, and then intermittently pressed into the microcracks, such as Figure 4 and Figure 5 As shown, the micro cracks are better blocked. Thus, pulse grouting (pulse dynamic grouting) can improve the sealing of the borehole while reducing the amount of grouting, thereby improving the efficiency of gas extraction), until the control mechanism 30 monitors that the grouting pressure reaches the upper limit pressure of the pressure relief valve 4 (the pressure relief valve 4 can prevent the grouting mechanism 20 from continuously grouting and causing excessive pressure in the grouting branch pipe 1 or the closed space, thereby damaging the dynamic sealing system of the extraction borehole, or damaging the surrounding wall of the sealing section formed by the sealing cavity A, thereby ensuring the sealing effect of the dynamic seal, effectively ensuring the subsequent dynamic sealing quality, and improving the reliability and durability of the seal), the control mechanism 30 controls the first solenoid valve 3 to close and the second solenoid valve 10 to open (the first solenoid valve 3 and the second solenoid valve 10 have linkage control, the first solenoid valve 3 is opened and the second solenoid valve 10 is closed, and the first solenoid valve 3 is closed and the second solenoid valve 10 is opened), and the gas extraction operation continues to achieve efficient gas extraction from coal seam B.

[0070] The dynamic sealing system for the extraction borehole provided in the embodiment of the present invention forms a sealing cavity A between two sacs 7, and the sealing cavity A is filled with slurry. The sealing effect of the extraction borehole C is judged by the linkage control between the concentration sensor 8 and the pressure gauge 9, and the monitoring data is transmitted to the control mechanism 30. The control mechanism 30 controls the operation of the grouting mechanism 20 according to the monitoring data. The first solenoid valve 3, the pressure relief valve 4, the concentration sensor 8, the pressure gauge 9, and the second solenoid valve 10 can intelligently link and control the injection amount of the slurry in the sealing cavity A to achieve dynamic plugging of the extraction borehole C. When the sealing of the extraction borehole C fails, the extraction borehole C can be quickly plugged without a limit on the number of times, and long-term dynamic and stable sealing can be achieved when the extraction borehole C fails multiple times. In addition, the first solenoid valve 3, the pressure relief valve 4, the concentration sensor 8, the pressure gauge 9, and the second solenoid valve 10 in the embodiment of the present application are intelligently linked and controlled by the control mechanism 30, and the degree of intelligence is high.

[0071] The embodiment of the present application solves the problems of failure of part C of the extraction borehole in the current drilling site under the influence of disturbance, high sealing cost, serious air leakage, low extraction purity, etc. The intelligent linkage control between the various components can accurately and efficiently locate the failed boreholes, and carry out targeted sealing of the failed boreholes caused by the extraction action. Compared with the traditional process of increasing the grouting length of the sealing section to improve the sealing of the borehole, it is more targeted and goal-oriented. It can also realize dynamic sealing when the subsequent boreholes fail multiple times, making the sealing process more accurate and reliable, with long-term stability and reliable durability.

[0072] At the same time, the intermittent grouting characteristics can improve the sealing quality and stability, thereby improving the extraction effect and having good economic benefits. It provides strong technical support for promoting the green development of the coal industry and helping to achieve the country's "dual carbon goals", and is of great significance for promoting the optimization and upgrading of the energy structure.

[0073] Furthermore, the slurry adopts low-viscosity sealing slurry, so as to better realize the dynamic sealing of the extraction borehole C. A method for preparing a slurry provided in an embodiment of the present application is: using sodium-based bentonite with good swelling properties as a base material, adding sodium carboxymethyl cellulose as a binder, and supplemented with sodium methyl ester sulfonate (MES) and polyacrylamide (PAM) as surfactants and water retaining agents, respectively. The ratio of MES to PAM is: MES dosage is 4%, PAM dosage is 0.8%, and the water-to-material ratio is 10:1. The prepared low-viscosity sealing slurry has a test viscosity of 77mPa·s.

[0074] Optional, such as Figure 1As shown, the control mechanism 30 includes a monitoring substation 301, an editable logic controller 302 and a ground monitoring platform 303. The first solenoid valve 3, the pressure relief valve 4, the concentration sensor 8, the pressure gauge 9, the second solenoid valve 10 and the grouting mechanism 20 are all electrically connected to the monitoring substation 301. The monitoring substation 301 is electrically connected to the editable logic controller 302. The editable logic controller 302 is electrically connected to the ground monitoring platform 303.

[0075] The monitoring data is transmitted to the editable logic controller 302 through the monitoring substation 301, and then transmitted to the intelligent control center in the ground monitoring platform 303. The intelligent control center gives corresponding control instructions and performs operations. The intelligent control center is a conventional computer control system, which is an existing device and program and will not be described in detail here.

[0076] Further, when the grouting mechanism 20 includes a grouting cylinder 201 and a pulse grouting pump 202, the grouting cylinder 201 and the pulse grouting pump 202 are electrically connected to the monitoring substation 301. The editable logic controller 302 transmits the pulse signal to the monitoring substation 301, and the monitoring substation 301 transmits the pulse signal to the pulse grouting pump 202, thereby realizing intermittent pulse grouting of the pulse grouting pump 202 to the sealing cavity A, and realizing dynamic pulse sealing.

[0077] Pulse grouting can realize intermittent pulse grouting, which is realized by the reciprocating motion of the piston of the power structure in the pulse grouting pump 202. The reciprocating motion of the piston forms a pulse pressure in the grouting branch pipe 1. This pulse pressure is non-constant and has a non-constant rate of change. It changes the action mode of constant pressure, so that the grouting slurry can be more effectively injected into the sealing cavity A under the action of pressure, and then pressed into the micro cracks, such as Figure 4 and Figure 5 As shown, the micro cracks in the coal seam B are better blocked, and after a relatively stable network skeleton is formed, the gas extraction operation of the coal seam B is carried out. The pulse grouting pump 202 in the grouting mechanism 20 realizes intermittent pulse grouting by receiving the pulse signal of the editable logic controller 302, which can effectively improve the sealing quality and stability.

[0078] Furthermore, if Figure 1 As shown, the extraction borehole dynamic sealing system also includes an explosion-proof power supply 40. The monitoring substation 301 is electrically connected to the explosion-proof power supply 40. The explosion-proof power supply 40 is electrically connected to the editable logic controller 302. Thus, the explosion-proof power supply 40 can power all structures connected to the monitoring substation 301 and the editable logic controller.

[0079] Another embodiment of the present invention provides a drainage borehole C sealing method, based on the above-mentioned drainage borehole dynamic sealing system, comprising:

[0080] In the coal seam B within the drilling site, extraction boreholes C are constructed sequentially according to the layout plan.

[0081] The first solenoid valve 3, the pressure relief valve 4, the low-pressure one-way valve 5, the high-pressure one-way valve 6 and the low-pressure one-way valve 5 are sequentially arranged on the grouting branch pipe 1. A bag 7 is respectively arranged at the position of the two low-pressure one-way valves 5 on the grouting branch pipe 1, and the low-pressure one-way valve 5 connects the grouting branch pipe 1 and the bag 7.

[0082] A grouting branch pipe 1 is arranged in a drainage borehole C, so that two bags 7 arranged on the grouting branch pipe 1 are arranged in the drainage borehole C, and a sealed cavity A is formed between the two bags 7 after being filled with slurry. The sealed cavity A is located between the elastic area and the original stress area in the stress concentration area of ​​the drainage borehole C. The high-pressure one-way valve 6 is located in the sealed cavity A and connects the grouting branch pipe 1 and the sealed cavity A.

[0083] One end of all grouting branch pipes 1 is connected to one end of grouting main pipe 2. The other end of grouting main pipe 2 is connected to grouting mechanism 20.

[0084] The concentration sensor 8, the pressure gauge 9 and the second electromagnetic valve 10 are arranged on the extraction branch pipe 50. One end of an extraction branch pipe 50 extends into an extraction borehole C, and the other ends of all the extraction branch pipes 50 are connected to one end of the extraction main pipe 60.

[0085] The first solenoid valve 3, the pressure relief valve 4, the low-pressure one-way valve 5, the high-pressure one-way valve 6, the concentration sensor 8, the pressure gauge 9, the second solenoid valve 10, and the grouting mechanism 20 are all electrically connected to the control mechanism 30 to complete the installation of the extraction borehole dynamic sealing system.

[0086] When performing the "two blocking and one injection" operation, the control mechanism 30 controls the grouting mechanism 20, the first solenoid valve 3 and the two low-pressure one-way valves 5 to open, and injects slurry into the bags 7 set at the positions of the two low-pressure one-way valves 5 on each grouting branch pipe 1 through the grouting main pipe 2 and the grouting branch pipe 1 until the sealed cavity A is formed between the two bags 7 after the slurry is filled, and then the control mechanism 30 controls the high-pressure one-way valve 6 to open, so that the sealed cavity A is filled with slurry, thereby forming a sealing section, that is, the sealing section of the extraction borehole C is arranged between the elastic area and the original stress area in the stress concentration area by using the "two blocking and one injection" sealing method, and the two bags 7 realize the sealing of the sealed cavity A, and the two bags 7 and the sealing section realize the sealing of the extraction borehole C together. After that, the control mechanism 30 controls the first solenoid valve 3 to close, and the second solenoid valve 10 to open, and the gas extraction operation begins.

[0087] In practice, in the extraction drilling site, affected by the action of mining, micro cracks are generated around the sealing section formed by the sealing cavity A of the extraction borehole C filled with slurry, resulting in air leakage when the sealing of the extraction borehole C fails, which in turn leads to a decrease in the extraction concentration.

[0088] After that, the dynamic sealing step is performed multiple times, and the dynamic sealing step includes: the concentration sensor 8 monitors the gas extraction concentration value of the extraction branch pipe 50, and transmits the gas extraction concentration value to the control mechanism 30. When the gas extraction concentration value is less than the preset concentration value (such as the preset concentration value can be 50% of the normal extraction concentration value, and the specific value of the preset concentration value can be set according to the difference in extraction parameters of each coal mine working face. When the gas extraction concentration value is less than the preset concentration value, the sealing effect of the extraction borehole C becomes worse), the control mechanism 30 controls the second solenoid valve 10 to close for the first preset time (such as the first preset time can be 30 minutes). If the control mechanism 30 monitors that the pressure of the pressure gauge 9 within the first preset time is less than the preset pressure value (that is, the pressure value displayed by the pressure gauge 9 remains unchanged or increases slowly, it proves that the seal of the extraction borehole C has failed; if the pressure of the pressure gauge 9 continues to rise, it proves that the sealing of the extraction borehole C is intact), the control mechanism 30 controls the first solenoid valve 3 to open, and controls the grouting mechanism 20 to perform intermittent grouting (the control mechanism 30 transmits the pulse signal to the grouting mechanism 20, thereby realizing the intermittent pulse grouting of the grouting mechanism 20. Compared with the ordinary equal pressure grouting process, the intermittent pulse grouting forms more seepage channels, and forms a relatively stable "network skeleton" composed of multiple seepage channels around the sealing section, which can effectively improve the sealing quality and stability. In addition, the intermittent pulse grouting enables the grouting slurry to be more effectively injected into the sealing cavity A under the intermittent action of the grouting pressure, and then intermittently pressed into the microcracks, such as Figure 4 and Figure 5 As shown, the micro cracks are better blocked. Thus, pulse grouting (pulse dynamic grouting) can improve the sealing of the borehole while reducing the amount of grouting, thereby improving the efficiency of gas extraction), until the control mechanism 30 monitors that the grouting pressure reaches the upper limit pressure of the pressure relief valve 4 (the pressure relief valve 4 can prevent the grouting mechanism 20 from continuously grouting and causing excessive pressure in the grouting branch pipe 1 or the closed space, thereby damaging the dynamic sealing system of the extraction borehole, or damaging the surrounding wall of the sealing section formed by the sealing cavity A, thereby ensuring the sealing effect of the dynamic seal, effectively ensuring the subsequent dynamic sealing quality, and improving the reliability and durability of the seal), the control mechanism 30 controls the first solenoid valve 3 to close and the second solenoid valve 10 to open (the first solenoid valve 3 and the second solenoid valve 10 have linkage control, the first solenoid valve 3 is opened and the second solenoid valve 10 is closed, and the first solenoid valve 3 is closed and the second solenoid valve 10 is opened), and the gas extraction operation continues to achieve efficient gas extraction from coal seam B.

[0089] The sealing method of the extraction borehole C provided in the embodiment of the present invention forms a sealing cavity A between two bags 7, fills the sealing cavity A with slurry, judges the sealing effect of the extraction borehole C through the linkage control between the concentration sensor 8 and the pressure gauge 9, and transmits the monitoring data to the control mechanism 30, and the control mechanism 30 controls the operation of the grouting mechanism 20 according to the monitoring data. The first solenoid valve 3, the pressure relief valve 4, the concentration sensor 8, the pressure gauge 9, and the second solenoid valve 10 can intelligently link and control the injection amount of the slurry in the sealing cavity A to achieve dynamic plugging of the extraction borehole C, and can quickly achieve plugging of the extraction borehole C when the sealing of the extraction borehole C fails, without a limit on the number of times, and can achieve long-term dynamic and stable sealing when the extraction borehole C fails multiple times. In addition, the first solenoid valve 3, the pressure relief valve 4, the concentration sensor 8, the pressure gauge 9, and the second solenoid valve 10 in the embodiment of the present application are intelligently linked and controlled by the control mechanism 30, and the degree of intelligence is high.

[0090] The slurry adopts low-viscosity sealing slurry, thereby further facilitating the dynamic sealing of the subsequent extraction borehole C.

[0091] Further, the first solenoid valve 3, the pressure relief valve 4, the low-pressure one-way valve 5, the high-pressure one-way valve 6, the concentration sensor 8, the pressure gauge 9, the second solenoid valve 10, and the grouting mechanism 20 are all electrically connected to the control mechanism 30, including:

[0092] The first solenoid valve 3 , the pressure relief valve 4 , the concentration sensor 8 , the pressure gauge 9 , the second solenoid valve 10 , and the grouting mechanism 20 are all electrically connected to the monitoring substation 301 .

[0093] The monitoring substation 301 and the editable logic controller 302 are electrically connected.

[0094] The editable logic controller 302 is electrically connected to the ground monitoring platform 303 .

[0095] Optionally, the sealing method for the extraction borehole C further includes: electrically connecting the monitoring substation 301 to the explosion-proof power supply 40 . Electrically connecting the explosion-proof power supply 40 to the editable logic controller 302 .

[0096] The various embodiments in this specification are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other. Each embodiment focuses on the differences from other embodiments.

[0097] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, a person of ordinary skill in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some or all of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present application.

Claims

1. A dynamic sealing system for extraction boreholes, characterized in that: It includes control mechanism, grouting mechanism, grouting main pipe, grouting subsystem and extraction subsystem; The grouting subsystem includes a grouting branch pipe, a first solenoid valve, a pressure relief valve, a low-pressure one-way valve, a high-pressure one-way valve and a bladder; The first solenoid valve, the pressure relief valve, the low-pressure one-way valve, the high-pressure one-way valve and the low-pressure one-way valve are sequentially arranged on the grouting branch pipe; A bag is respectively arranged at the position of the two low-pressure one-way valves on the grouting branch pipe, and the low-pressure one-way valve is connected to the grouting branch pipe and the bag; A grouting branch pipe is arranged in one of the extraction boreholes, so that the two bags arranged on the grouting branch pipe are arranged in the extraction borehole, and a sealed cavity is formed between the two bags filled with slurry, and the sealed cavity is located between the elastic area and the original stress area in the stress concentration area of ​​the extraction borehole, and the high-pressure one-way valve is located in the sealed cavity and connects the grouting branch pipe and the sealed cavity; One end of all the grouting branch pipes is connected to one end of the grouting main pipe; The other end of the grouting main pipe is connected to the grouting mechanism; The extraction subsystem includes an extraction branch pipe, a concentration sensor, a pressure gauge and a second solenoid valve; The concentration sensor, the pressure gauge and the second solenoid valve are arranged on the extraction branch pipe; One end of one of the extraction branch pipes extends into one of the extraction boreholes, and the other ends of all the extraction branch pipes are connected to one end of the extraction main pipe; The first solenoid valve, the pressure relief valve, the low-pressure one-way valve, the high-pressure one-way valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the control mechanism.

2. The dynamic sealing system for extraction borehole according to claim 1, characterized in that: The slurry is a low-viscosity sealing slurry.

3. The dynamic sealing system for extraction borehole according to claim 1, characterized in that: The control mechanism includes a monitoring substation, an editable logic controller and a ground monitoring platform; The first solenoid valve, the pressure relief valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the monitoring substation; The monitoring substation is electrically connected to the editable logic controller; The editable logic controller is electrically connected to the ground monitoring platform.

4. The dynamic sealing system for extraction borehole according to claim 3, characterized in that: Also includes an explosion-proof power supply; The monitoring substation is electrically connected to the explosion-proof power supply; The explosion-proof power supply is electrically connected to the editable logic controller.

5. A method for dynamic sealing of a drainage borehole, characterized in that: The extraction borehole dynamic sealing system according to any one of claims 1 to 4 comprises: A first solenoid valve, a pressure relief valve, a low-pressure one-way valve, a high-pressure one-way valve and a low-pressure one-way valve are sequentially arranged on the grouting branch pipe; a bag is respectively arranged at the position where the two low-pressure one-way valves are located on the grouting branch pipe, and the low-pressure one-way valve is connected to the grouting branch pipe and the bag; A grouting branch pipe is arranged in a drainage borehole, so that the two bags arranged on the grouting branch pipe are arranged in the drainage borehole, and a sealed cavity is formed between the two bags filled with slurry, and the sealed cavity is located between the elastic area and the original stress area in the stress concentration area of ​​the drainage borehole, and the high-pressure one-way valve is located in the sealed cavity and connects the grouting branch pipe and the sealed cavity; One end of all the grouting branch pipes is connected to one end of the grouting main pipe; the other end of the grouting main pipe is connected to the grouting mechanism; The concentration sensor, the pressure gauge and the second electromagnetic valve are arranged on the extraction branch pipe; one end of the extraction branch pipe extends into an extraction borehole, and the other ends of all the extraction branch pipes are connected to one end of the extraction main pipe; The first solenoid valve, the pressure relief valve, the low-pressure one-way valve, the high-pressure one-way valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the control mechanism; The control mechanism controls the grouting mechanism, the first solenoid valve and the two low-pressure one-way valves to open, and injects slurry into the bags arranged at the positions of the two low-pressure one-way valves on each grouting branch pipe through the grouting main pipe and the grouting branch pipe until a sealed cavity is formed between the two bags filled with slurry, and then the control mechanism controls the high-pressure one-way valve to open, so that the sealed cavity is filled with slurry, and then the control mechanism controls the first solenoid valve to close and the second solenoid valve to open, and gas extraction operation starts; The dynamic sealing step is then performed multiple times, and the dynamic sealing step includes: the concentration sensor monitors the gas extraction concentration value of the extraction branch pipe, and transmits the gas extraction concentration value to the control mechanism; when the gas extraction concentration value is less than the preset concentration value, the control mechanism controls the second solenoid valve to close for a first preset time; if the control mechanism monitors that the pressure of the pressure gauge within the first preset time is less than the preset pressure value, the control mechanism controls the first solenoid valve to open, and controls the grouting mechanism to intermittently grout until the control mechanism monitors that the grouting pressure reaches the upper limit pressure of the pressure relief valve, and the control mechanism controls the first solenoid valve to close, and the second solenoid valve to open, and the gas extraction operation continues.

6. The method for dynamic sealing of a drainage borehole according to claim 5, characterized in that: The slurry is a low-viscosity sealing slurry.

7. The method for dynamic sealing of a drainage borehole according to claim 5, characterized in that: The first solenoid valve, the pressure relief valve, the low-pressure one-way valve, the high-pressure one-way valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the control mechanism, including: The first solenoid valve, the pressure relief valve, the concentration sensor, the pressure gauge, the second solenoid valve, and the grouting mechanism are all electrically connected to the monitoring substation; Electrically connect the monitoring substation and the editable logic controller; The editable logic controller is electrically connected to the ground monitoring platform.

8. The method for dynamic sealing of a drainage borehole according to claim 7, characterized in that: Also includes: Electrically connecting the monitoring substation to an explosion-proof power supply; The explosion-proof power supply is electrically connected to the editable logic controller.

Images