Gas extraction while drilling for soft and outburst coal seam adopts blowout preventer system and its operation method

Abstract

The application discloses a kind of broken soft protruding coal seam gas extraction while drilling blowout preventer and its operation method, the system includes orifice device, first water residue separation device, second gas-water residue separation device, third water residue separation device and the negative pressure extraction pipeline with multiple gas extraction openings;First gas-water residue separation device is also provided with first buffer interface, and the first buffer interface is communicated with gas extraction opening by first buffer pressure relief device, and the third gas-water residue separation device is also provided with second buffer interface, and the second buffer interface is communicated with gas extraction opening by second buffer pressure relief device.The application is provided with resistance limiting flow, buffer pressure relief, gas-water residue separation and removal and other devices, realizes the "drilling while extracting" of broken soft protruding coal seam gas extraction borehole and effectively handles abnormal jetting hole, with fast response speed, controllable drilling jetting intensity, strong abnormal condition handling capacity, multiple drilling technology, no leakage of gushing gas in drill pipe and other advantages.

Description

Technical Field

[0001] This invention relates to the field of coal mine drilling technology, specifically to a blowout prevention system and its operation method for gas drainage during drilling in soft, outburst-prone coal seams. Background Technology

[0002] In high-gas and coal and gas outburst mines, about 60% of the coal seams are broken and soft outburst seams. As the mining depth increases year by year, the proportion of broken and soft outburst seams is getting larger and larger. Gas extraction and management are the key to ensuring safe production in coal mines.

[0003] Drilling extraction is an important technical means for the prevention and control of gas disasters. However, due to the characteristics of broken and soft outburst coal seams, such as broken coal body structure, low mechanical strength, high gas content and high gas pressure, drilling blowouts are very likely to occur during drilling. Moreover, the blowout time, gas and coal slag emission volume are uncontrollable. In severe cases, it may lead to accidents such as excessive gas concentration at the drilling site, equipment burial, and gas explosion.

[0004] To ensure safe drilling in soft, outburst-prone coal seams, the main method currently used is the wellhead blowout preventer, which removes the gas gushing out of the borehole during drilling. However, this method has the following main shortcomings:

[0005] (1) There is a lack of monitoring and early warning for gas eruptions in boreholes, and the response measures are lagging behind.

[0006] (2) When a blowout occurs in the borehole, it is impossible to limit the intensity of the blowout of coal and gas or to seal the borehole, resulting in a large amount of gas, coal slag and water mixture being ejected from the borehole at high speed, which may lead to gas exceeding the limit at the drilling site, personnel injury, and in severe cases, gas explosion accident.

[0007] (3) The blowout prevention device at the borehole is mainly suitable for gas extraction during normal drilling, but its volume is limited. When the amount of gas and coal slag ejected from the borehole is large, it is very easy to exceed its rated processing capacity, resulting in gas leakage and coal slag blockage.

[0008] (4) Depending on the drilling and perforation medium, the drilling process of soft and protruding coal seams is mainly divided into two categories: gas drilling and flushing fluid drilling. The existing blowout prevention device is only applicable to one of the construction processes and is not universal, which leads to the duplication of drilling equipment.

[0009] (5) During the construction of gas drainage boreholes, in addition to leakage from the annular gap between the drill rod and the borehole wall, gas may also gush out from the inner hole of the drill rod. The existing blowout prevention device at the borehole opening does not prevent gas from gushing out from the inner hole of the drill rod.

[0010] In view of the above-mentioned deficiencies, the designers of this invention, through dedicated research and design, and by integrating their long-term experience and achievements in related industries, have designed a blowout prevention system for gas drainage in soft, outburst-prone coal seams during drilling, and its operation method, to overcome the shortcomings of current blowout prevention devices for gas drainage boreholes in soft, outburst-prone coal seams, such as untimely handling of in-hole anomalies, uncontrollable borehole blowout intensity, weak ability to handle abnormal working conditions, limited applicable drilling technology, and untreated gas gushing from the drill pipe borehole. Summary of the Invention

[0011] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of this invention is to provide a blowout prevention system and its operation method for gas drainage in soft and protruding coal seams during drilling, so as to solve the technical problems of uncontrollable blowout intensity in downhole boreholes and inability to deal with abnormal working conditions in a timely and effective manner in the prior art.

[0012] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0013] A blowout prevention system for gas drainage in soft, outburst-prone coal seams during drilling includes an orifice device, a first gas-water-slag separation device, a second gas-water-slag separation device, a third gas-water-slag separation device, and a negative pressure drainage pipeline with multiple gas drainage ports.

[0014] The orifice device is provided with an orifice device gas outlet and an orifice device water slag outlet. The orifice device gas outlet is connected to the gas inlet of the first gas-water-slag separator, which is located on the first gas-water-slag separator. The orifice device water slag outlet is connected to the water slag inlet of the first gas-water-slag separator, which is located on the second gas-water-slag separator. The first gas-water-slag separator is also provided with a first gas-water-slag outlet, which is connected to the water slag inlet of the second gas-water-slag separator, which is located on the second gas-water-slag separator. The water-slag separation device is also provided with a second gas-water-slag separation device water-slag outlet, which is connected to the third gas-water-slag separation device water-slag inlet of the third gas-water-slag separation device. The third gas-water-slag separation device is also provided with a third gas-water-slag separation device water-slag outlet. The first gas-water-slag separation device is also provided with a first gas inlet, the second gas-water-slag separation device is provided with a second gas inlet, and the third gas-water-slag separation device is provided with a third gas inlet. The first gas inlet, the second gas inlet, and the third gas inlet are respectively connected to the gas extraction port.

[0015] The first gas-water-slag separation device is also provided with a first buffer interface, which is connected to the gas extraction port via a first buffer pressure relief device. The third gas-water-slag separation device is also provided with a second buffer interface, which is connected to the gas extraction port via a second buffer pressure relief device.

[0016] The present invention also has the following technical features:

[0017] Specifically, the orifice device includes an orifice sleeve, a resistance-increasing and flow-limiting device, and a sealing and diverting device sequentially connected and sleeved on the drill pipe; the resistance-increasing and flow-limiting device includes a resistance-increasing and flow-limiting shell with open ends and a flow-limiting rubber cylinder coaxially sleeved inside the resistance-increasing and flow-limiting shell; the flow-limiting rubber cylinder is provided with a flow channel, and multiple rubber cylinder ribs are arranged axially at intervals on the outer wall of the flow-limiting rubber cylinder; the resistance-increasing and flow-limiting shell is provided with a hydraulic oil inlet and a hydraulic oil outlet, and the flow-limiting rubber cylinder can contract or expand radially along the resistance-increasing and flow-limiting shell under the pressure of hydraulic oil, so as to increase or decrease the radial area of ​​the flow channel inside the flow-limiting rubber cylinder;

[0018] The sealed diversion device includes a hollow sealed diversion shell with open ends. The upper part of the sealed diversion shell is provided with a gas outlet and a gas concentration sensor mounting port, and the lower part is provided with a water slag outlet. The end of the sealed diversion shell away from the resistance limiting shell is also provided with a sealing gasket and a sealing cap.

[0019] Furthermore, the first buffer pressure relief device includes a first hollow mounting rod open at both ends and a first airbag coaxially mounted on the first hollow mounting rod. The first hollow mounting rod extends out of the first airbag through mounting ports at both ends. One end of the first hollow mounting rod is connected to a first buffer interface, and the other end is connected to a gas extraction port. The second buffer pressure relief device includes a second hollow mounting rod open at both ends and a second airbag coaxially mounted on the second hollow mounting rod. The second hollow mounting rod extends out of the second airbag through mounting ports at both ends. One end of the second hollow mounting rod is connected to a second buffer interface, and the other end is connected to a gas extraction port.

[0020] The first hollow mounting rod and the second hollow mounting rod each have several ventilation holes on their outer walls, and both the first hollow mounting rod and the second hollow mounting rod are equipped with a one-way gas valve at their rear ends; both the first airbag and the second airbag can expand or contract with changes in the gas pressure inside the airbag.

[0021] Furthermore, the first gas-water-slag separation device includes a first housing, the water-slag inlet of the first gas-water-slag separation device is located on the upper part of the front side wall of the first housing, the water-slag outlet of the first gas-water-slag separation device is located on the lower part of the rear side wall of the first housing, the first buffer interface is located on the upper part of the rear side wall of the first housing, and the first gas inlet and the first gas-water-slag separation device gas inlet are both located on the top plate of the first housing.

[0022] The second gas-water-slag separation device includes a second shell, the water-slag inlet of the second gas-water-slag separation device is located on the upper part of the front side wall of the second shell, the water-slag outlet of the second gas-water-slag separation device is located on the lower part of the rear side wall of the second shell, the top plate of the second shell is provided with a second gas inlet and a second shell gas inlet, and the second shell gas inlet is connected to the drill rod through a pipeline;

[0023] The third gas-water-slag separation device includes a third shell, the water-slag inlet of the third gas-water-slag separation device is located on the upper part of the front side wall of the third shell, the water-slag outlet of the third gas-water-slag separation device is located on the lower part of the rear side wall of the third shell, the second buffer interface is located on the upper part of the rear side wall of the third shell, and a third gas inlet is provided on the top plate of the third shell.

[0024] The first housing, the second housing, and the third housing are all equipped with self-sensing slag discharge components with identical structures; the first housing is also equipped with a spray dust suppression component.

[0025] Furthermore, the spray dust suppression assembly disposed within the first housing includes a spray mechanism horizontally disposed within the first housing, a gas passage baffle vertically disposed below the top plate of the first housing, and an isolation baffle inclinedly disposed between the spray mechanism and the gas passage baffle; the isolation baffle and the gas passage baffle form an acute angle of ~°; the gas passage baffle is provided with a plurality of gas passage holes arranged in an array;

[0026] The self-sensing slag discharge assembly disposed within the first housing includes an inclined pressure plate disposed between the front and rear side walls of the first housing; the front end of the inclined pressure plate abuts against the front side wall of the first housing, and the vertical distance between the front end of the inclined pressure plate and the bottom plate of the first housing is less than the vertical distance between the water slag inlet of the first gas-water slag separator and the bottom plate of the first housing; the rear end of the inclined pressure plate is connected to a slag discharge baffle, which is disposed on a slag discharge port opened on the rear side wall of the first housing; a slag discharge pipe is also connected to the slag discharge port, and a return spring is disposed inside the slag discharge pipe, one end of which is connected to the slag discharge baffle.

[0027] Furthermore, the spraying mechanism includes a spraying pipeline and multiple atomizing nozzles disposed on the spraying pipeline, with the spraying end of the atomizing nozzles facing the gas inlet of the first gas-water-slag separation device.

[0028] Furthermore, a liftable support mechanism is provided below one end of the inclined pressure plate near the front side wall of the first housing.

[0029] Furthermore, a gas concentration sensor is installed inside the gas concentration sensor mounting port, and gas pressure sensors are installed on both the first and second buffer pressure relief devices. A displacement sensor for measuring the displacement of the reset spring is installed inside the slag discharge pipe.

[0030] This invention also protects a method for operating a blowout prevention system for gas drainage during drilling in soft, outburst-prone coal seams, specifically including:

[0031] During the drilling process, the gas concentration sensor collects the gas concentration in the sealed diversion device in real time and sends the collected gas concentration to the remote server. The gas pressure sensor collects the gas pressure of the first buffer pressure relief device and the gas pressure of the second buffer pressure relief device in real time and sends the collected gas pressure of the first buffer pressure relief device and the gas pressure of the second buffer pressure relief device to the remote server.

[0032] When the collected methane concentration rises to the drilling stop threshold, drilling is stopped; hydraulic oil is injected into the resistance limiting device to expand and limit the flow of the limiting rubber cylinder, and the gas check valve of the first buffer pressure relief device and the gas check valve of the second buffer pressure relief device are opened.

[0033] When the collected gas concentration drops to the drilling start threshold, hydraulic oil is unloaded from the resistance limiting device, and the gas check valves of the first and second buffer pressure relief devices are closed.

[0034] Furthermore, the drilling stop threshold is a gas concentration greater than or equal to 0.8%; the drilling start threshold is a gas concentration less than or equal to 0.5%.

[0035] Compared with the prior art, the beneficial effects of the present invention are:

[0036] (1) The device of the present invention is equipped with a foldable buffer pressure relief device. When coal and gas vents appear in the borehole, the buffer pressure relief device works, which buys time for gas drainage in the mine negative pressure drainage pipeline. When the gas pressure in the buffer pressure relief device exceeds the limit value, the gas one-way valve opens to achieve safe buffer pressure relief of gas.

[0037] (2) The gas-water-slag separation device classifies and treats the dust and slag generated during drilling, achieving efficient dust removal and automatic slag cleaning, and is suitable for gas drilling and flushing fluid drilling.

[0038] (3) The method of the present invention achieves “drilling and pumping at the same time” and effective treatment of abnormal blowouts in gas extraction boreholes in soft and outburst coal seams by setting up resistance limiting, buffering and depressurization, automatic separation and removal of gas, water and slag, and inclined pressure in the inner hole of the drill rod. It has the advantages of fast processing response, controllable borehole blowout intensity, strong ability to handle abnormal working conditions, applicability to multiple drilling processes, and no leakage of gas gushing out of the drill rod.

[0039] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0040] Figure 1 This is a diagram showing the components of a blowout prevention system used for gas drainage during drilling in soft, outburst-prone coal seams.

[0041] Figure 2 This is a schematic diagram of the orifice device structure in Embodiment 1;

[0042] Figure 3 This is a schematic diagram of the resistance-increasing and current-limiting device in Example 1;

[0043] Figure 4 This is a schematic diagram of the flow-limiting rubber cylinder structure in Example 1;

[0044] Figure 5 This is a schematic diagram of the sealing diversion device structure in Example 1;

[0045] Figure 6 This is a schematic diagram of the first gas-water-slag separation device in Example 1;

[0046] Figure 7 This is a schematic diagram of the self-sensing slag discharge component structure in Example 1.

[0047] Meaning of the labels in the attached figures:

[0048] 1-Orifice device, 2-First gas-water-slag separation device, 3-Second gas-water-slag separation device, 4-Third gas-water-slag separation device, 5-Negative pressure extraction pipeline, 6-First buffer pressure relief device, 7-Second buffer pressure relief device, 8-Gas one-way valve, 9-Self-sensing slag discharge assembly, 10-Spray dust suppression assembly.

[0049] 11-Orifice sleeve; 12-Resistance-increasing and flow-limiting device; 13-Sealing and flow-diverting device; 21-Gas inlet of the first gas-water-slag separator; 22-Water-slag inlet of the first gas-water-slag separator; 23-Water-slag outlet of the first gas-water-slag separator; 24-First gas delivery port; 25-First buffer interface; 26-First shell; 31-Water-slag inlet of the second gas-water-slag separator; 32-Water-slag outlet of the second gas-water-slag separator; 33-Second gas delivery port; 34-Second shell; 35- Second shell gas inlet; 41-Third gas-water-slag separator water-slag inlet; 42-Third gas-water-slag separator water-slag outlet; 43-Third gas inlet; 44-Second buffer interface; 45-Third shell; 51-Gas extraction port; 61-First hollow mounting rod; 62-First airbag; 71-Second hollow mounting rod; 72-Second airbag; 91-Inclined pressure plate; 92-Slag discharge baffle; 93-Slag discharge pipe; 94-Reset spring; 95-Liftable support mechanism;

[0050] 101-Spraying mechanism; 102-Gas passage baffle; 103-Isolation baffle; 121-Resistance-increasing and flow-limiting housing; 122-Flow-limiting rubber cylinder; 131-Sealing and flow-diverting housing;

[0051] 1011-Spray pipe, 1012-Atomizing nozzle, 1021-Gas through hole; 1211-Hydraulic oil inlet, 1212-Hydraulic oil outlet, 1221-Rubber cylinder reinforcing plate; 1311-Orifice device gas outlet, 1312-Orifice device water slag outlet, 1313-Gas concentration sensor mounting port, 1314-Sealing gasket, 1315-Sealing gland.

[0052] The specific content of the present invention will be further explained in detail below with reference to the accompanying drawings and specific embodiments. Detailed Implementation

[0053] It should be understood that the specific embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0054] The terms "upper," "lower," "front," "rear," "top," and "bottom," etc., used in this invention to indicate orientation or positional relationships are merely for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. "Inner" and "outer" refer to the inner and outer contours of the corresponding components, and should not be construed as limitations on the invention. The terms "front" and "rear" used in this solution, as well as... Figure 1 As shown.

[0055] Furthermore, the terms "first," "second," and other ordinal numbers are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of that feature.

[0056] In this invention, unless otherwise stated, the terms "installation," "connection," "linking," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0057] Example 1

[0058] like Figure 1As shown, following the above technical solution, this invention discloses a blowout prevention system for gas drainage in soft, outburst-prone coal seams during drilling, comprising an orifice device 1, a first gas-water-slag separation device 2, a second gas-water-slag separation device 3, a third gas-water-slag separation device 4, and a negative pressure drainage pipeline 5 with multiple gas drainage ports 51; wherein, the orifice device 1, the first gas-water-slag separation device 2, the second gas-water-slag separation device 3, and the third gas-water-slag separation device 4 are connected sequentially by pipelines, and flanges are provided at the connection points.

[0059] The gas and water residue generated inside the borehole can be transported through the orifice device 1 to the first gas-water-residue separator 2. The first gas-water-residue separator 2 is used to remove dust from the input gas. The treated gas enters the negative pressure extraction pipeline 5. The first gas-water-residue separator 2 can also be used to remove the incoming water residue. The second gas-water-residue separator 3 and the third gas-water-residue separator 4 are used for buffering when a blowout occurs. That is, when the first gas-water-residue separator 2 is not fast enough to discharge the residue and water, the water residue that sequentially enters the second gas-water-residue separator 3 and the third gas-water-residue separator 4 from the first gas-water-residue separator 2 can continue to be discharged.

[0060] The orifice device 1 is equipped with an orifice device gas outlet 1311 and an orifice device water slag outlet 1312. The orifice device gas outlet 1311 is connected to the gas inlet 21 of the first gas-water-slag separator 2, which is located on the first gas-water-slag separator 2. The orifice device water slag outlet 1312 is connected to the water slag inlet 22 of the first gas-water-slag separator 2, which is located on the first gas-water-slag separator 2. The first gas-water-slag separator 2 is also equipped with a first gas-water-slag separator water slag outlet 23, which is connected to the second gas-water-slag separator water slag inlet 31 of the second gas-water-slag separator 3. The gas-water-slag separation device 3 is also provided with a second gas-water-slag separation device water-slag outlet 32, which is connected to the third gas-water-slag separation device water-slag inlet 41 on the third gas-water-slag separation device 4. The third gas-water-slag separation device 4 is also provided with a third gas-water-slag separation device water-slag outlet 42. The first gas-water-slag separation device 2 is also provided with a first gas inlet 24, the second gas-water-slag separation device 3 is provided with a second gas inlet 33, and the third gas-water-slag separation device 4 is provided with a third gas inlet 43. The first gas inlet 24, the second gas inlet 33, and the third gas inlet 43 are respectively connected to the gas extraction port 51.

[0061] The first gas-water-slag separation device 2 is also provided with a first buffer interface 25, which is connected to the gas extraction port 51 via the first buffer pressure relief device 6. The third gas-water-slag separation device 4 is also provided with a second buffer interface 44, which is connected to the gas extraction port 51 via the second buffer pressure relief device 7. Both the first buffer pressure relief device 6 and the second buffer pressure relief device 7 are connected to the gas extraction port 51 of the negative pressure extraction pipeline via a gas extraction flame-retardant rubber hose.

[0062] As a preferred embodiment of this invention, such as Figure 2 As shown, the orifice device 1 includes an orifice sleeve 11, a resistance-increasing and flow-limiting device 12, and a sealing and flow-diverting device 13, which are sequentially connected and sleeved on the drill pipe; as shown... Figure 3 and Figure 4 As shown, the resistance-increasing and current-limiting device 12 includes a resistance-increasing and current-limiting housing 121 open at both ends and a current-limiting rubber cylinder 122 coaxially sleeved inside the resistance-increasing and current-limiting housing. Both the resistance-increasing and current-limiting housing 121 and the current-limiting rubber cylinder 122 are hollow cylindrical structures. A flow channel is provided inside the current-limiting rubber cylinder 122, and multiple rubber cylinder ribs 1221 are axially spaced on the outer wall of the current-limiting rubber cylinder 122. The function of the rubber cylinder ribs 1221 is to separate the hydraulic oil. Under the squeezing action of the hydraulic oil, the current-limiting rubber cylinder 122 deforms, and adjacent rubber cylinders... The cylinder between the reinforcing ribs 1221 is concave inward to increase resistance and limit the flow of fluid in the drill pipe, ultimately ensuring equal expansion pressure and balanced force. The resistance-increasing and flow-limiting housing 121 has a hydraulic oil inlet 1211 and a hydraulic oil outlet 1212. The hydraulic oil inlet 1211 allows hydraulic oil to enter the resistance-increasing and flow-limiting housing 121, causing the flow-limiting rubber cylinder 122 to deform under pressure. The hydraulic oil outlet 1212 allows hydraulic oil to flow out of the resistance-increasing and flow-limiting housing 121, allowing the flow-limiting rubber cylinder 122 to return to its original position. During normal drilling, the resistance-increasing and flow-limiting housing 121 of the resistance-increasing and flow-limiting device 12 is in contact with the flow-limiting rubber cylinder 122. During nozzle drilling, the state of the resistance-increasing and flow-limiting housing 121 and the flow-limiting rubber cylinder 122 is as follows: Figure 3 As shown.

[0063] The flow-limiting rubber cylinder 122 can contract or expand radially along the resistance-increasing flow-limiting shell 121 under the pressure of hydraulic oil, so as to increase or decrease the radial area of ​​the flow channel inside the flow-limiting rubber cylinder 122; when a blowout occurs in the borehole, the flow-limiting rubber cylinder 122 contracts radially to reduce the flow area, limit the amount of returned gas and slag, weaken the blowout intensity of the borehole, and reduce the processing pressure of the drilling site.

[0064] like Figure 5As shown, the sealing diversion device 13 includes a hollow sealing diversion shell 133 with open ends. The sealing diversion shell 133 is a hollow cylindrical structure. The upper part is provided with a gas outlet 1311 and a gas concentration sensor mounting port 1313 of the orifice device, and the lower part is provided with a water slag outlet of the orifice device 1. The end of the sealing diversion shell 131 away from the resistance-increasing and flow-limiting shell 121 is also provided with a sealing gasket 1314 and a sealing cap 1315. The sealing gasket 1314 includes two semi-circular sealing components with the same structure and arranged in a mirror symmetrical manner. When replacing the sealing gasket 1314, only the sealing cap 1315 needs to be removed to complete the replacement. Compared with traditional orifice seals, it does not require disassembling the drill rod of the drilling tool, is quick to replace, and has good sealing performance.

[0065] As a preferred embodiment, the first buffer pressure relief device 6 includes a first hollow mounting rod 61 with open ends and a first airbag 62 coaxially mounted on the first hollow mounting rod 61. The first hollow mounting rod 61 passes through the mounting ports at both ends of the first airbag 62. One end of the first hollow mounting rod 61 is connected to the first buffer interface 25, and the other end is connected to the gas extraction port 51. The second buffer pressure relief device 7 includes a second hollow mounting rod 71 with open ends and a second airbag 72 coaxially mounted on the second hollow mounting rod 71. The second hollow mounting rod 71 passes through the mounting ports at both ends of the second airbag 72. One end of the second hollow mounting rod 71 is connected to the second buffer interface 44, and the other end is connected to the gas extraction port 51.

[0066] Several ventilation holes are provided on the outer walls of the first hollow mounting rod 61 and the second hollow mounting rod 71, and a gas one-way valve 8 is provided at the rear end of the first hollow mounting rod 61 and the second hollow mounting rod 71; the first airbag 62 and the second airbag 72 can expand or contract with the change of gas pressure inside the airbag.

[0067] In this embodiment, both the first hollow mounting rod 61 and the second hollow mounting rod 71 are made of seamless steel pipes. The first airbag 62 and the second airbag 72 are both cylindrical structures made of non-porous synthetic fiber fabric. When installing the first airbag 62 and the second airbag 72 according to the construction site conditions, a certain amount of space should be reserved to facilitate the opening of the airbags. During normal drilling, the first airbag 62 and the second airbag 72 are in a contracted state. When a blowout occurs, because gas enters the airbags, the first airbag 62 and the second airbag 72 will be in an inflated state.

[0068] As a preferred embodiment, the first gas-water-slag separation device 2 includes a first housing 26, a water-slag inlet 22 of the first gas-water-slag separation device is located on the upper part of the front side wall of the first housing 26, a water-slag outlet 23 of the first gas-water-slag separation device is located on the lower part of the rear side wall of the first housing 26, a first buffer interface 25 is located on the upper part of the rear side wall of the first housing 26, and a first gas inlet 24 and a gas inlet 21 of the first gas-water-slag separation device are both located on the top plate of the first housing 26.

[0069] The second gas-water-slag separation device 3 includes a second housing 34. The water-slag inlet 31 of the second gas-water-slag separation device is located on the upper part of the front side wall of the second housing 34, and the water-slag outlet 32 ​​of the second gas-water-slag separation device is located on the lower part of the rear side wall of the second housing 34. A second gas outlet 33 and a second housing gas inlet 35 are provided on the top plate of the second housing 34. The second housing gas inlet 35 is connected to the drill pipe through a pipeline. When drilling is stopped, drill pipe is added, or drill pipe is disassembled, the valve provided on the pipeline can be opened, and the residual gas in the drill pipe can be sent into the second gas-water-slag separation device 3 through the pipeline by means of a mud pump.

[0070] The third gas-water-slag separation device 4 includes a third housing 45, a slag inlet 41 of the third gas-water-slag separation device is located on the upper part of the front side wall of the third housing 45, a slag outlet 42 of the third gas-water-slag separation device is located on the lower part of the rear side wall of the third housing 45, a second buffer interface 44 is located on the upper part of the rear side wall of the third housing 45, and a third gas outlet 43 is provided on the top plate of the third housing 45.

[0071] The first shell 26, the second shell 34, and the third shell 45 are all equipped with self-sensing slag discharge components 9 with identical structures; the first shell 26 is also equipped with a spray dust suppression component 10. The spray dust suppression component 10 is used to spray dust to remove gas entering the shell, and the gravity self-sensing slag discharge component 9 is used for the self-sensing discharge of water slag inside the shell.

[0072] As a preferred embodiment of this invention, such as Figure 6As shown, the spray dust suppression assembly 10 installed within the first housing 26 includes a spray mechanism 101 horizontally installed within the first housing 26, a gas passage baffle 102 vertically installed below the top plate of the first housing 26, and an isolation baffle 103 inclined between the spray mechanism 101 and the gas passage baffle 102. The isolation baffle 103 and the gas passage baffle 102 form an acute angle of 30-60°. Multiple gas passage holes 1021 are arranged in an array on the gas passage baffle 102. The diameter of the gas passage holes 1021 is 30mm. The isolation baffle 103 extends the flow path of water mist and gas, buffers and condenses the water mist and gas, and prevents water mist and gas from directly entering the negative pressure extraction pipeline 5 through the gas passage baffle 102. The gas passage baffle 102 allows the gas to pass through after being buffered and condensed by the isolation baffle 103. Ultimately, this extends the flow path of the atomized gas.

[0073] like Figure 7 As shown, the self-sensing slag discharge assembly 9 installed inside the first housing 26 includes an inclined pressure plate 91 inclined between the front sidewall and the rear sidewall of the first housing 26; the front end of the inclined pressure plate 91 abuts against the front sidewall of the first housing 26, and the vertical distance between the front end of the inclined pressure plate 91 and the bottom plate of the first housing 26 is less than the vertical distance between the water slag inlet 22 of the first gas-water slag separator and the bottom plate of the first housing 26, that is, the front end of the inclined pressure plate 91 is located below the water slag inlet 22 of the first gas-water slag separator, and the rear end of the inclined pressure plate 91 is connected to a slag discharge baffle 92, which is located on a slag discharge port opened on the rear sidewall of the first housing 26; a slag discharge pipe 93 is also connected to the slag discharge port, and a return spring 94 is installed inside the slag discharge pipe 93. One end of the return spring 94 is connected to the slag discharge baffle 92. With the help of the inclined pressure plate 91, the water slag entering the first housing 26 through the water slag inlet 22 of the first gas-water slag separator can flow from front to back along the inclined pressure plate 91 and enter the slag discharge pipe 93.

[0074] As a preferred embodiment, the spray mechanism 101 includes a spray pipe 1011 and a plurality of atomizing nozzles 1012 disposed on the spray pipe 1011. The spraying ends of the atomizing nozzles 1012 face the gas inlet 21 of the first gas-water-slag separation device. Preferably, the spray pipe 1011 is arranged in a rectangle and the atomizing nozzles 1012 on the spray pipe 1011 are arranged at equal intervals. The spray pipe 1011 is connected to an atomizing water pipe disposed in the first housing 26.

[0075] As a preferred embodiment, a liftable support mechanism 95 is further provided below one end of the inclined pressure plate 91 near the front sidewall of the first housing 26. The liftable support mechanism 95 can be a cross-type lifting mechanism of an existing lifting structure. When the inclined pressure plate 91 slides downward along the front sidewall of the first housing 26 under the pressure of water slag, the liftable support mechanism 95 can support the inclined pressure plate 91. After the water slag is removed, the inclined pressure plate 91 can rise and reset under the action of the liftable support mechanism 95.

[0076] In a preferred embodiment, a gas concentration sensor is installed in the gas concentration sensor mounting port 1313. Gas pressure sensors are installed on both the first buffer pressure relief device 6 and the second buffer pressure relief device 7. A displacement sensor for measuring the displacement of the reset spring 94 is installed in the slag discharge pipe 93. The gas concentration sensor is used to collect gas concentration information, the gas pressure sensor is used to collect gas pressure data, and the displacement sensor is used to collect the displacement data of the reset spring 94. Finally, the data collected by each sensor is transmitted to a remote server.

[0077] As a preferred embodiment, a real-time image acquisition device can also be deployed around the first buffer decompression device 6 and the second buffer decompression device 7 to better monitor the morphological changes of the first airbag 62 and the second airbag 72.

[0078] During normal drilling and gas extraction, the system of this invention:

[0079] A mud pump supplies flushing fluid for drilling and slag removal into the borehole, carrying coal slag generated during drilling and methane gas released from the borehole. The fluid enters the first gas-water-slag separation device 2, the second gas-water-slag separation device 3, and the third gas-water-slag separation device 4 in sequence to separate methane gas, flushing fluid, and drill cuttings. The methane gas is then drawn away by the negative pressure extraction pipeline 5 in the mine, and the drill cuttings are discharged after reaching the set mass.

[0080] When the drilling and spraying of the present invention malfunctions:

[0081] That is, when the detected gas concentration exceeds 0.8%, drilling should be stopped immediately. Then, oil should be injected through the hydraulic oil inlet 1211 of the resistance-increasing and flow-limiting device 12. The flow-limiting rubber sleeve 122 of the resistance-increasing and flow-limiting device 12 deforms, reducing the annular gap area between the drill rod and the borehole, limiting the amount of gas and slag returned, and weakening the intensity of the borehole blowout. After the gas ejected from the borehole enters the first gas-water-slag separation device 2, a portion of the gas is drawn away by the negative pressure extraction pipeline 5. The remaining gas that cannot be drawn away in time enters the first buffer pressure relief device 6, gradually filling the first airbag 62. When the gas pressure in the first airbag 62 exceeds the limit value, the gas... When valve 8 is opened, the gas in the first airbag 62 is extracted using the negative pressure extraction pipeline 3. At the same time, some water slag carrying gas that cannot be discharged in time enters the second gas-water slag separation device 3 and the third gas-water slag separation device 4 in sequence. When the remaining gas that cannot be extracted in time enters the second buffer pressure relief device 7, it gradually fills the second airbag 72. When the gas pressure in the second airbag 72 exceeds the limit value, the gas check valve 8 opens the second buffer pressure relief device 7. When the gas concentration drops to the drilling start threshold, it indicates that the drilling and blowout have ended. Then, the high-pressure oil in the resistance increasing and flow limiting device 12 is discharged through the hydraulic oil unloading port 1212, the resistance increasing and flow limiting device is restored, and normal drilling resumes.

[0082] To verify the application effect of the device of the present invention, a system performance test was conducted in the factory workshop, with manual input... Figure 1 The system shown is filled with methane gas at a concentration of approximately 10%, causing the methane gas concentration inside the sealed diversion device 13 to rise rapidly. Based on the methane gas concentration data collected by the gas concentration sensor, the operator can operate the remote controller to turn on the hydraulic oil supply switch within 0.1 seconds, causing the resistance-increasing and flow-limiting device 12 to work. Within 1 second, the annular gap between the drill pipe and the resistance-increasing and flow-limiting housing is reduced, weakening the intensity of the gas blowout. During gas extraction using the system of this invention, the methane gas concentration in the plant area is 0. The above verification experiment proves the good blowout prevention effect of this system.

[0083] Example 2

[0084] This embodiment discloses an operation method for gas drainage in soft, outburst-prone coal seams using a blowout prevention system during drilling. The operation method is implemented using the blowout prevention system for gas drainage in soft, outburst-prone coal seams disclosed in Embodiment 1, specifically including:

[0085] During the drilling process, the gas concentration sensor collects the gas concentration in the sealed diversion device in real time and sends the collected gas concentration to the remote server. The gas pressure sensor collects the gas pressure of the first buffer pressure relief device and the gas pressure of the second buffer pressure relief device in real time and sends the collected gas pressure of the first buffer pressure relief device and the gas pressure of the second buffer pressure relief device to the remote server.

[0086] When the collected methane gas concentration rises to the drilling stop threshold, drilling stops. At this time, the first airbag 62 and the second airbag 72 will expand rapidly. Hydraulic oil is injected into the resistance limiting device 12 to achieve the expansion and flow limiting of the flow limiting rubber cylinder 122, and the gas check valve 8 of the first buffer pressure relief device 6 and the gas check valve 8 of the second buffer pressure relief device 7 are opened. The methane gas in the first buffer pressure relief device 6 and the second buffer pressure relief device 7 is extracted using the negative pressure extraction pipeline 5.

[0087] When the collected gas concentration drops to the drilling threshold, it indicates that hydraulic oil is being unloaded from the resistance limiting device 12. At this time, the first airbag 62 and the second airbag 72 will contract rapidly, which can close the gas check valve 8 of the first buffer pressure relief device 6 and the gas check valve 8 of the second buffer pressure relief device 7, and stop the extraction of gas from the first buffer pressure relief device 6 and the second buffer pressure relief device 7 using the negative pressure extraction pipeline 5.

[0088] In this embodiment, the drilling stop threshold is a gas concentration greater than or equal to 0.8%; the drilling start threshold is a gas concentration less than or equal to 0.5%.

[0089] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0090] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0091] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A blowout prevention system for gas drainage during drilling in soft, outburst-prone coal seams, characterized in that, It includes an orifice device (1), a first gas-water-slag separation device (2), a second gas-water-slag separation device (3), a third gas-water-slag separation device (4), and a negative pressure extraction pipeline (5) with multiple gas extraction ports (51). The orifice device (1) is provided with an orifice device gas outlet (1311) and an orifice device water slag outlet (1312). The orifice device gas outlet (1311) is connected to the first gas-water-slag separator gas inlet (21) provided on the first gas-water-slag separator (2). The orifice device water slag outlet (1312) is connected to the first gas-water-slag separator water slag inlet (22) provided on the first gas-water-slag separator (2). The first gas-water-slag separator (2) is also provided with a first gas-water-slag separator water slag outlet (23). The first gas-water-slag separator water slag outlet (23) is connected to the second gas-water-slag separator water slag inlet (31) provided on the second gas-water-slag separator (3). The gas-water-slag separation device (3) is also provided with a second gas-water-slag separation device water slag outlet (32), which is connected to the third gas-water-slag separation device water slag inlet (41) on the third gas-water-slag separation device (4). The third gas-water-slag separation device (4) is also provided with a third gas-water-slag separation device water slag outlet (42). The first gas-water-slag separation device (2) is also provided with a first gas inlet (24), the second gas-water-slag separation device (3) is provided with a second gas inlet (33), and the third gas-water-slag separation device (4) is provided with a third gas inlet (43). The first gas inlet (24), the second gas inlet (33), and the third gas inlet (43) are respectively connected to the gas extraction port. The first gas-water-slag separation device (2) is also provided with a first buffer interface (25), which is connected to the gas extraction port (51) via the first buffer pressure relief device (6). The third gas-water-slag separation device (4) is also provided with a second buffer interface (44), which is connected to the gas extraction port (51) via the second buffer pressure relief device (7). The orifice device (1) includes an orifice sleeve (11), a resistance-increasing and flow-limiting device (12), and a sealing and diverting device (13) sequentially connected and sleeved on the drill rod; the resistance-increasing and flow-limiting device (12) includes a resistance-increasing and flow-limiting shell (121) open at both ends and a flow-limiting rubber cylinder (122) coaxially sleeved in the resistance-increasing and flow-limiting shell; the flow-limiting rubber cylinder (122) is provided with a flow channel, and multiple rubber cylinder ribs (1221) are arranged axially at intervals on the outer wall of the flow-limiting rubber cylinder (122); the resistance-increasing and flow-limiting shell (121) is provided with a hydraulic oil inlet (1211) and a hydraulic oil outlet (1222); the flow-limiting rubber cylinder (122) can contract or expand radially along the resistance-increasing and flow-limiting shell (121) under the pressure of hydraulic oil, so as to increase or decrease the radial area of ​​the flow channel inside the flow-limiting rubber cylinder (122); The sealing diversion device (13) includes a hollow sealing diversion shell (131) with open ends. The upper part of the sealing diversion shell (131) is provided with a gas outlet (1311) of the orifice device and a gas concentration sensor mounting port (1313), and the lower part is provided with a water slag outlet of the orifice device (1). The end of the sealing diversion shell (131) away from the resistance limiting shell (121) is also provided with a sealing gasket (1314) and a sealing cap (1315). The first gas-water-slag separation device (2) includes a first housing (26), the first gas-water-slag separation device water slag inlet (22) is located on the upper part of the front side wall of the first housing (26), the first gas-water-slag separation device water slag outlet (23) is located on the lower part of the rear side wall of the first housing (26), the first buffer interface (25) is located on the upper part of the rear side wall of the first housing (26), and the first gas inlet (24) and the first gas-water-slag separation device gas inlet (21) are both located on the top plate of the first housing (26); The second gas-water-slag separation device (3) includes a second housing (34), the water slag inlet (31) of the second gas-water-slag separation device is located on the upper part of the front side wall of the second housing (34), the water slag outlet (32) of the second gas-water-slag separation device is located on the lower part of the rear side wall of the second housing (34), the top plate of the second housing (34) is provided with a second gas outlet (33) and a second housing gas inlet (35), and the second housing gas inlet (35) is connected to the drill rod through a pipeline; The third gas-water-slag separation device (4) includes a third housing (45), the water-slag inlet (41) of the third gas-water-slag separation device is located on the upper part of the front side wall of the third housing (45), the water-slag outlet (42) of the third gas-water-slag separation device is located on the lower part of the rear side wall of the third housing (45), the second buffer interface (44) is located on the upper part of the rear side wall of the third housing (45), and a third gas outlet (43) is provided on the top plate of the third housing (45). The first housing (26), the second housing (34) and the third housing (45) are all provided with self-sensing slag discharge components (9) with the same structure; the first housing (26) is also provided with a spray dust suppression component (10). The spray dust suppression assembly (10) disposed within the first housing (26) includes a spray mechanism (101) horizontally disposed within the first housing (26), a gas passage baffle (102) vertically disposed below the top plate of the first housing (26), and an isolation baffle (103) inclinedly disposed between the spray mechanism (101) and the gas passage baffle (102); the isolation baffle (103) and the gas passage baffle (102) form an acute angle of 30 to 60 degrees; the gas passage baffle (102) is provided with a plurality of gas passage holes (1021) arranged in an array. The self-sensing slag discharge assembly (9) set in the first housing (26) includes an inclined pressure plate (91) inclined between the front side wall and the rear side wall of the first housing (26); the front end of the inclined pressure plate (91) abuts against the front side wall of the first housing (26), and the vertical distance between the front end of the inclined pressure plate (91) and the bottom plate of the first housing (26) is less than the vertical distance between the water slag inlet (22) of the first gas-water slag separation device and the bottom plate of the first housing (26); the rear end of the inclined pressure plate (91) is connected to the slag discharge baffle (92), and the slag discharge baffle (92) is set on the slag discharge port opened on the rear side wall of the first housing (26); a slag discharge pipe (93) is also connected to the slag discharge port, and a reset spring (94) is set in the slag discharge pipe (93), and one end of the reset spring (94) is connected to the slag discharge baffle (92).

2. The blowout prevention system for gas drainage during drilling in soft, outburst-prone coal seams as described in claim 1, characterized in that, The first buffer pressure relief device (6) includes a first hollow mounting rod (61) with open ends and a first airbag (62) coaxially mounted on the first hollow mounting rod (61). The first hollow mounting rod (61) passes through the mounting ports opened at both ends of the first airbag (62) and exits through the first airbag (62). One end of the first hollow mounting rod (61) is connected to the first buffer interface (25), and the other end is connected to the gas extraction port (51). The second buffer pressure relief device (7) includes a second hollow mounting rod (71) with open ends and a second airbag (72) coaxially mounted on the second hollow mounting rod (71). The second hollow mounting rod (71) passes through the mounting ports opened at both ends of the second airbag (72) and exits through the second airbag (72). One end of the second hollow mounting rod (71) is connected to the second buffer interface (44), and the other end is connected to the gas extraction port (51). The outer walls of the first hollow mounting rod (61) and the second hollow mounting rod (71) are provided with several vent holes, and the rear ends of the first hollow mounting rod (61) and the second hollow mounting rod (71) are provided with gas one-way valves (8); the first airbag (62) and the second airbag (72) can expand or contract with the change of gas pressure inside the airbag.

3. The blowout prevention system for gas drainage during drilling in soft, outburst-prone coal seams as described in claim 1, characterized in that, The spray mechanism (101) includes a spray pipe (1011) and a plurality of atomizing nozzles (1012) disposed on the spray pipe (1011), with the spraying end of the atomizing nozzle (1012) facing the gas inlet (21) of the first gas-water-slag separation device.

4. The blowout prevention system for gas drainage during drilling in soft, outburst-prone coal seams as described in claim 1, characterized in that, A liftable support mechanism (95) is also provided below one end of the inclined pressure plate (91) near the front side wall of the first housing (26).

5. The blowout prevention system for gas drainage during drilling in soft, outburst-prone coal seams as described in claim 1, characterized in that, A gas concentration sensor is installed in the gas concentration sensor installation port (1313). Gas pressure sensors are installed on the first buffer pressure relief device (6) and the second buffer pressure relief device (7). A displacement sensor for measuring the displacement of the reset spring (94) is installed in the slag discharge pipe (93).

6. A method for operating a blowout prevention system for gas drainage in a soft, outburst-prone coal seam as described in claim 5, characterized in that, Specifically, it includes: During the drilling process, the gas concentration sensor collects the gas concentration in the sealed diversion device in real time and sends the collected gas concentration to the remote server. The gas pressure sensor collects the gas pressure of the first buffer pressure relief device and the gas pressure of the second buffer pressure relief device in real time and sends the collected gas pressure of the first buffer pressure relief device and the gas pressure of the second buffer pressure relief device to the remote server. When the collected methane concentration rises to the drilling stop threshold, drilling is stopped; hydraulic oil is injected into the resistance limiting device to expand and limit the flow of the limiting rubber cylinder, and the gas check valve of the first buffer pressure relief device and the gas check valve of the second buffer pressure relief device are opened. When the collected gas concentration drops to the drilling start threshold, hydraulic oil is unloaded from the resistance limiting device, and the gas check valves of the first and second buffer pressure relief devices are closed.

7. The method for operating a blowout prevention system for gas drainage in soft, outburst-prone coal seams during drilling, as described in claim 6, is characterized in that... The drilling stop threshold is a methane concentration greater than or equal to 0.8%; the drilling start threshold is a methane concentration less than or equal to 0.5%.

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