1692results about "Gas removal" patented technology

The invention relates to a hydraulic fracturing anti-reflection technology for pumping and exploring gas by drilling a hole in a coal mine well, comprising the following steps sequentially: (1) selecting a fracturing location; (2) determining the pressure type according to observed coal type, laneway arrangement and construction development degree, and ways of top soleplate bedding plane borehole hydraulic fracturing, top soleplate translamellar borehole hydraulic fracturing, the coal bed bedding plane borehole hydraulic fracturing or the coal bed translamellar borehole hydraulic fracturing can be adopted; (3) determining borehole parameters for constructing drilling, wherein, the borehole parameters include borehole length, borehole height, aperture, obliquity angle and azimuth angle; (4) designing the hydraulic fracturing, including injected water volume and injection pressure; (5) borehole washing; (6) draining; (7) examining the fracturing effect, if the fracturing effect is in accordance with the requirement, the following step is carried out, if not, turning to step (4); and (8) entering a pipeline for pumping and discharging. The technology enhances the air permeability of the coal bed, reduces the gas emission rate of an excavation working face, and obviously promotes the pumping and exploring capability and the pumping and exploring effect of the single borehole. The pumping and discharging efficiency is improved, the pumping and discharging time is shortened and the damage of the gas is maximally eliminated.

The present invention relates to a bag type paste-injecting hole-sealing equipment and its hole-sealing method. Said bag type paste-injecting hole-sealing equipment includes the following several portions: bag, internal end supporting component, middle portion supporting component, external end supporting component, paste injection control valve, reverse check valve and pressure control pin. Besides, said invention also provides the concrete steps of said hole-sealing method.

The invention discloses an in-hole drilling tool integrating drilling, slotting and punching a coal seam and a using method thereof. The in-hole drilling tool comprises a water supple device or an air supple device, a high-pressure sealing drill pipe, a slotting and punching valve and a drill bit. The water supply device and the air supply device are connected with the high-pressure sealing drill pipe at an orifice. The slotting and punching valve is installed between the high-pressure sealing drill pipe and the drill bit. The in-hole drilling tool is essentially used for drilling and anti-reflective outburst eliminating after drilling of soft outburst coal seam. The using method is as follows: after the drilling construction is finished, a water supplier with a pressure release valve is used for starting a high-pressure pumping station to improve the pressure and the flux for water supply; high-pressure water current at the pumping station drives the slotting and punching valve to act for closing an axial liquid passage and opening a radial liquid passage; and high-pressure jet current realizes slotting or punching through a cutting nozzle or a punching nozzle. The invention has novel design and easy operation, is safe and reliable, improves the outburst elimination efficiency and realizes the integrated operation of drilling, slotting or punching and outburst eliminating.

Provided is a method for heating coal seam and extracting coal seam gas. Firstly, a plurality of vertical wells are drilled from the ground to the coal seam, after the drilled well reached to the coal seam, the coal seam is inserted with a screen tube casing (4), the section above the coal seam is inserted with a heat insulation casing (31) and the well is correspondingly fixed. At least one well of the wells is selected to be a heat source injection well (1) and other wells are gas production wells (2), steam with high temperature and high pressure is injected into the heat source injection well (1) to perform fracturing to communicate all the wells in the network. Drainage and pressure reduction are performed to the gas production wells (2) to extract the mixed gas of the coal seam gas and steam. The mixed gas of the coal seam gas and steam is cooled by known cooling method so as to obtain gaseous coal seam gas and liquid distilled water to realize the separation of the mixed gas. According to the change of the coal seam temperature, the heat source injection well (1) and the gas production wells (2) are allocated to control the heated coal seam and extract coal seam gas. The method of he invention can effectively perform the extraction of the coal seam gas, accelerate the coal seam extraction speed, and improve the extraction rate.

The invention provides a system and a method for predicting the coal and gas outburst risk of a mine in real time, which relate to a system and a method for judging mine natural disaster of coal and gas outburst risk degree through combination of artificial intelligence and expert analysis. The system uses a microseismic signal for reflecting the ground stress intensity and the gas outburst quantity for reflecting the gas change as analysis parameters to be combined with the expert experience, and can improve the predicting accuracy of the coal and gas outburst risk to high than 90 percent. The system and the method are characterized in that the system mainly consists of a data collection module, a data transmission module, a real-time data tracking and analysis center and an integrated early warning module, wherein after the data collection module collects underground data, the data is transmitted to the real-time data tracking and analysis center through the data transmission modulefor calculation, analysis and reasoning, and the integrated early warning module gives the early warning when a reasoning result shows that the risk occurs. The invention is applicable to similar mines with the coal and gas outburst risk.

A portable monitor used to measure landfill gas and landfill well parameters. The portable monitor includes a control unit and a measuring unit that can communicate wirelessly with one another. The control unit and/or measuring unit can include a heating arrangement to increase the temperature of one or more components in the control unit and/or measuring unit in cold environments.

The invention discloses a method for extracting gas from high gas low permeability coal seam by punching, slotting, pressure releasing and permeability increasing, comprising the following steps: whena drill is drilled into a predetermined position of the coal seam, coal bodies at both sides of a drill hole are cut in the drill hole by high pressure water jet with a certain pressure and flow; a flat slot is formed at both sides of the drill hole; the cut coal bodies is led out the hole by the high pressure water jet. The exposed area of the coal body at the slotted part in the drill hole aregreatly increased, namely that an extremely thin protective layer is exploited with local scope of the flat slot, which enlarges effective influential range of pressure releasing, permeability increasing and gas discharging of the coal bodies in the drill hole, thus the air permeability of the coal bodies is increased about 200-300 times, the average amount of single-hole gas extraction reaches 0.3m<3>/min, the concentration of the gas extraction is 30-60%, gas drainage rate of working face of coal extraction is more than 50%, the number of drill holes for gas drainage is reduced by 10-20% after slotting, pressure releasing and permeability increasing. The method realizes the safety, high efficiency and uniform extraction of the gas from the high gas low permeability outburst coal seam, and changes high gas coal seam with outburst danger into low gas coal seam without outburst danger.

A method to suck pressure relief firedamp along Y-shape ventilating gob roof of the empty tunnel is characterized in that: in the high-firedamp coal mining working-face pressure relief zone along the empty tunnel gob roof, it sucks the stripping and free firedamp from the exploiting and pressure relief layer which gathers in the gob upper part and the ring slit loop through the slit channel formed by the mining influence on the gob upper rock stratum through the dip sucking firedamp bore-hole which are distributed in the pressure relief ring slit loop. The pressure relief ring slit loop locates in the separation layer slit zone above the caving zone on the Y-shape ventilating working-face along the empty tunnel gob roof. The invention resolves the air firedamp overrun in the corner and the return airway on the coal mining working-face basically, realizes the sucking and application of the high density firedamp, improves the resource utilization ratio, exploits the high firedamp coal seam without coal wedges, improves the mine resource recovery and assures the high-efficiency and safe exploitation of the coal mining working-face.

The invention relates to a method for integrated comprehensive management of gas in a low-permeability single coal bed, which can effectively solve the problem of comprehensive management and utilization of the gas. A technical scheme of the method comprises the following steps of: firstly, drilling holes, wherein a high-torque drilling machine and a rifle or a trihedral drill stem are used for solving the phenomenon of clamping the drill stem caused by collapsing and jetting of the holes in the hole drilling process; and then, performing hydraulic fracturing permeability improvement on the coal body, drilling holes for pre-split blasting, performing gas drainage, and recycling the drained gas, thereby implementing the integrated management of the gas. With the method provided by the invention, the permeability of the coal body is improved, a pre-draining rate of the gas is improved, and the drained gas is recycled, so that the drilled holes are radically prevented from being blocked in the construction process, the problem of difficulties in draining the gas in the low-permeability coal bed with a drilling tool having insufficient capability in the drilling construction is solved, consequently, outburst risk of the coal and the gas is reduced, outburst accidents of the coal and the gas are reduced and even avoided, and mine production safety and lives of coal mine workers are ensured, so that the method brings great economic and social benefits.

The invention relates to a directional fracturing method in the coal mine and a fracturing permeability improvement outburst elimination device to ensure the coal-bed gas to release rapidly and continually in the coal mine. The method comprises the following steps: fracturing and drilling a bore on a preparing working face along the dip direction and strike direction of a coal bed, fixing a fracturing hole packer with an outer diameter matching with the pore diameter of a fracturing drilling bore into the fracturing drilling bore; connecting a fluid reservoir with a sand mixing machine, connecting the sand mixing machine with a fracturing pump package, and then connecting the fracturing pump package with the fracturing drilling bore; pumping formation fracturing fluid and proppant into the fracturing drilling bore to fracture the formation and sealing the fracturing drilling at above formation fracturing pressure, and completing directional fracturing permeability improvement outburst elimination in the coal mine, thus ensuring that the coal-bed gas discharges rapidly and continually relatively and solving the problems that drainage in low air permeability coal bed can only influence a limited range and the drainage attenuation period is short, improving the drainage rate by over 50% on primary base, decreasing the coal body dynamic phenomenon after fracturing and reginal stress influenced by fracturing, and having a significant effect for eliminating outburst.

This invention discloses a method for depressuring gas in ground drilled well and mining area. Before extracting coal a ground drilling well is drilled from ground to long distance, low breathing, high gas, projecting and soft covered seams, then extracting down seam. The gas from the up covered seam is exhausted from pipe.

Systems and methods are provided for a modular shelter that is suited for use as a safety chamber in an underground working environment. The shelter includes at least two wall units connected along a substantially sealed seam, a base unit that extends substantially throughout a floor plan of the shelter, and a roll cage that surrounds an outer extent of the shelter above the floor plan. The shelter may be configured to maintain a pressurized state in a closed condition. Each of the at least two wall units may share a substantially common shape and substantially common dimension, and may form a part of a wall, ceiling, and floor of the shelter. The shelter can also include various atmospheric control, circulation, and purge systems, and exterior and soft seal doors to assist in maintaining a livable atmosphere in the safety chamber.

A directional water pressure blasting method for improving coal bed gas permeability includes utilizing water pressure blasting splitting to change the structure of the coal and rock mass, firstly drilling holes inside a coal bed, performing high-pressure hydraulic cutting seam, and forming a deep flat slot around the drilling holes of the coal bed after cutting; and filling explosive into the drilling holes of the coal bed, then injecting water and sealing the hole, detonating the explosive to perform water pressure blasting, and enabling the periphery of the drilling holes of the coal bed to generate directional expanding fractures under the function of detonation pressures. Performing water pressure blasting in a high-gas low gas permeability coal bed can organically combine the waterpower and the explosive force of the explosive fully and reasonably, the water pressure blasting enables the cracks generated by hydraulic cutting seam to further expand and a directional expanding cross fracture net is formed on the periphery of the drilling holes of the coal bed, so that the gas permeability of the coal bed is greatly improved, the problem that the gas of the coal bed is hard to extract due to the small number of the cracks can be effectively solved, the concentrated stress of the coal bed is transferred to the deep of the coal mass, and the capacity of gas emission is improved. The directional water pressure blasting method for improving the coal bed gas permeability is simple in process, convenient to operate, safe, reliable, and good in controllability and effects.

The invention relates to a highly gassy coal seam group mining gob-side entry retaining Y-shaped ventilation and decompression gas extraction method. The invention is characterized in that: free desorption gas which comes from an adjacent decompression layer and is gathered into a roof plate decompression crack ring and a bottom plate decompression crack ring through crack channels which are formed by mining affection on roof plate coal seam and strata and bottom plate coal seam and strata is extracted in a gob-side entry through an upward extraction gas drill hole which is arranged inside the roof plate decompression crack ring and a downward extraction gas drill hole which is arranged inside the bottom plate decompression crack ring in a roof plate decompression area and a bottom plate decompression area of a gob-side entry retaining gob of a coal face of a primarily extracted coal seam of a highly gassy coal seam group. The highly gassy coal seam group mining gob-side entry retaining Y-shaped ventilation and decompression gas extraction method solves the problem of low extraction rate of the highly gassy low permeability coal seam group, simultaneously solves the ultralimit problem of airflow gas of spatial angles and return airways on the coal face of the primarily extracted coal seam of the highly gassy coal seam group, and realizes extraction utilization of high concentration gas and highly efficient and safe extraction of the highly gassy coal seam group without coal pillars.

According to one embodiment, a system for accessing a subterranean zone from the surface includes a well bore extending from the surface to the subterranean zone, and a well bore pattern connected to the junction and operable to drain fluid from a region of the subterranean zone to the junction.

The invention relates to an under-pressure grouting and hole sealing device and method for gas extraction drill air bag blocking. The device is characterized in that the device comprises an extraction pipe, a first tip air bag, a second tip air bag, a slurry outlet pipe and a grouting pipe, wherein the extraction pipe is composed of a first extraction pipe body, a second extraction pipe body and a third extraction pipe body, the first extraction pipe body is sleeved with the first tip air bag, a one-way needle valve is arranged on the first tip air bag, the slurry outlet pipe with a one-way check valve arranged inside penetrates through the first tip air bag, the outer end of the slurry outlet pipe is communicated with the grouting pipe, the third extraction pipe body is sleeved with the second tip air bag, a one-way needle valve is arranged on the second tip air bag, the two ends of the second extraction pipe body are connected with one end of the first extraction pipe body and one end of the third extraction pipe body respectively, the tip of the other end of the third extraction pipe body is provided with a plurality of sieve holes which allow gas to inflow, and the first tip air bag and the second tip air bag are filled with expansion agents in advance. The device and the method can be widely applied to permanent hole sealing for coal mine underground gas extraction hole drilling.

The invention relates to wind pressure air drilling equipment in a downhole soft outbursting coal bed and a process matched therewith. At present, as the consequent layer drilling characterized by high construction speed, low cost and high gas extraction efficiency becomes the primary option for coal control and gas control in coal mines, for soft outbursting coal beds, the gas extraction efficiency is directly dependant upon the pore-forming rate of the consequent layer drilling. The equipment comprises a boring machine, an air compressor, an orifice dust collection and dust removal device, a high-strength large through-hole drill rod, a drill bit with an inner core which can automatically fall off, and an antistatic explosion-protection PVC sieve tube; the boring machine which has large power and large torque supplies power to drilling construction; the orifice dust collection and dust removal device collects and eliminates slack carried out by wind from the orifice during drilling; and the antistatic explosion-protection PVC sieve tube is transferred from the interior of the high-strength large through-hole drill rod to the bottom of the orifice without lifting a drill on the completion of drilling, and at last remains in the orifice, thereby ensuring the completeness of drilling. The equipment and the process matched therewith provided by the invention has the advantages of increasing the pore-forming rate of the consequent layer drilling in soft outbursting coal beds, improving the effect of gas extraction, improving the working atmosphere of downhole air drilling, and protecting the production safety of outbursting coal mines.

According to one embodiment, a system for accessing a subterranean zone from the surface includes a well bore extending from the surface to the subterranean zone, and a well bore pattern connected to the junction and operable to drain fluid from a region of the subterranean zone to the junction.

The invention provides a high-pressure pneumatic blasting pressure relieving and transmission increasing method, comprising the steps of constructing a blasting drill hole in a coal layer, and carrying out high-pressure water jet seam cutting operation in the blasting drill hole at intervals, so that a lead seam groove is formed in a coal body around the blasting drill hole; feeding a blasting steel pipe with plugged top part into the blasting drill hole, forming a plurality of air vents at the front part of the blasting steel pipe, and sealing a section inside a hole opening of the blasting drill hole by 8-10 m, so as to form a cement plug; and connecting the blasting steel pipe with a high-pressure air station through a pipeline at the exposed end of the blasting steel pipe, and opening a valve arranged on the pipeline to inject high-pressure gas, so that the high-pressure gas is jetted by the blasting steel pipe from the air vents. On the basis of forming cracks and fractures formed in the fractures and cutting grooves of the original coal body, the high-pressure gas instantly impacts the blasting effect, so that the cracks and the fractures can be continuously expanded, and a lot of new fractures can be generated. Finally, a mutually communicated large fracture screen is formed in the coal body by using the blasting drill hole as a center, so that the purpose of pressure relief and transmission increase of the coal body can be realized. Furthermore, the high-pressure pneumatic blasting pressure relieving and transmission increasing method has the advantages of simple operation, easiness of realization and obvious effect.

A pressure alternate gas exhausting method by slotting and fracturing coal seams is applicable to the gas control of complex coal seams in a high-gas-content high-ground-stress area, aims to improve the air permeability of coal bodies and the capacity of drilling gas exhausting, and realizes continuous and efficient drilling gas exhausting of the complex coal seams. According to the pressure alternate gas exhausting method, drill holes to-be-slotted and drill holes to-be-fractured are formed by drilling coal seams to a coal floor; pressure-relief annular slots are formed in the bottom area of a coal seam section by virtue of the rotation of high pressure water jets in the drill holes; ground stress around the drill holes is manually discharged, and internal energy of coal seam gas is released; drilling pressure alternate gas exhausting is performed through designed drilling gas exhausting pipes which can shift the functions of gas exhausting and water injection fracturing; the water injection fracturing of the slotted drill holes and the gas exhausting of the fractured drill holes are performed simultaneously (or the water injection fracturing of the fractured drill holes and the gas exhausting of the slotted drill holes are performed simultaneously). Through alternate and repeated operations, the capacity of continuous and efficient drilling gas exhausting is increased; the effective influence range of drilling gas exhausting is increased by 2-4 times; the air permeability coefficient of coal bodies around the drill holes is increased by 200-500 times; the quantity of exhausted gas of drill holes with lengths of 100 m is increased by 2-5 times, so that the pressure alternate gas exhausting method has higher field application value and social benefits.

The invention discloses a system and a method for automatically measuring and recording gas pressure during coal seam hole sealing. The system comprises a gas extraction hole sealing device comprising a gas extraction pipeline; a rubber baffle group is respectively sleeved at two ends of the gas extraction pipeline; a curing material conveying pipeline and a sealing fluid conveying pipeline whichare parallel to the gas extraction pipeline are respectively arranged outside the gas extraction pipeline; a port of the gas extraction pipeline is connected with a pressure recorder; an inlet end ofthe curing material conveying pipeline is connected with a curing material driving device through a curing material high-pressure pipeline; a curing material outlet is positioned in at least one rubber baffle group; an inlet end of the sealing fluid conveying pipeline is connected with a sealing fluid driving device through a sealing fluid high-pressure pipeline; and a sealing fluid outlet is positioned between two rubber baffle groups. The invention can seal the peripheral cracks of the gas extraction hole, prevent leakage of the measured gas and comprehensively record the gas pressure; and the pressure-measuring time is short, and the working efficiency is high.

The invention discloses a test method of a drill hole gas extraction effective radius. The test method of the drill hole gas extraction effective radius comprises the following steps: selecting a sulfur hexafluoride (SF6) gas trace method to conduct spot test, under the condition of testing different pitches, sampling and collecting the SF6 gas required time which is detected by a detection hole, establishing a module at the basis of the Darcy law based on the occurrence of coal seam condition of the detecting location, simulating the flowing condition of the SF6 gas in a gas seepage field; calculating and obtaining the required time Ti'of the SF6 gas which moves to a sampling and collecting test hole, calculating a sampling and collecting effective coefficient a; detecting the required time of the SF6 gas based on the sampling and collecting detection hole detected by the SF6 gas trace method, calculating the required time which lowers the relative distance gas pressure below an effective value, and calculating the drill hole gas extraction effective radius based on power function relation between drill hole sampling and collecting gas effective extraction effective radius r (m) and the sampling and collecting time t (d). The test method of the drill hole gas extraction effective radius adopts combination of a direct method and an indirect method, and solves the problems that a plurality of defects exist by using the direct method to detect a drill hole gas extraction radius and extraction effective index is difficult to ascertain.

The invention discloses a refection reducing and outburst eliminating method for deep-hole hydraulic fracture driving gas shallow hole extraction. The method comprises the following steps of: gradually and alternately constructing hydraulic fracture holes and gas extraction holes in the coal bed direction in a coal mining working face tunnel, an airway or a tunneling working face, and performing high-pressure water injection and gas extraction; stopping injecting water after the water is injected into the hydraulic fracture holes for 0.5 to 5 hours, and changing gas extraction pipe joints to extract gas; after the hydraulic fracture hole or gas extraction concentration is lower than 5%, changing water injection pipes to perform static pressure water injection; and when the coal mining working face is recovered to the position 5 meters away from the static pressure water injection holes or the tunneled working face is tunneled again, stopping a pump or closing a static pressure water valve to stop water injection. According to the method, refection reduction of the gas-containing coal bed is realized, the gas extraction rate is improved, the gas in the mining space is effectively prevented from exceeding the limit, outburst risks of coal and gas are reduced, and safe and efficient recovery of coal is ensured. The method is simple and good in effect.

The invention relates to a permeability improvement technology for a coal bed gas reservoir cap by using three-dimensional fracture network modification. The technology is as follows: building a bedding horizontal well from ground to top and bottom plates of the coal bed of an area not mined; building bedding, three-dimensional cross-type or multi-branch long boreholes on the top and bottom plates of the coal bed of the area not mined through perforation and segmented fracturing or existing sinking and driving engineering, and then carrying out hydraulic fracturing; modifying the coal bed gas reservoir cap into a crisscross fracture network system to form a modified volume; building various types of drainage boreholes in the modified volume; and carrying out negative pressure extraction together with a fractured well, so that coal bed gas can be continuously desorbed and dispersed and then extracted out in large scale through the modified volume. According to the invention, the crisscross fracture network system is formed in the coal bed gas reservoir cap, so that the coal bed gas can be continuously desorbed and dispersed at negative pressure and then extracted out in large scale through the modified volume, thus the content of coal bed gas in the modified bed can be quickly reduced to be below the safety standard in the outburst prevention formulation, and safe and high-efficiency production of mines can be realized on the basis of forming scale coal bed gas development.

The invention discloses a coal and rock bore hydraulic fracture experimental apparatus, which comprises a sample device system, a confining pressure system, a fracture system, a sealing system and a monitoring system, wherein the sample device system comprises a sample cylinder, the bottom in the sample cylinder is provided with a screen drum of which the bottom is provided with a water outlet pipe, a sample is accommodated in the sample cylinder above the screen drum, and a simulated bore is formed in the sample; the confining pressure system comprises an air filling subsystem and a water filling subsystem; the fracture system comprises a fracture high-pressure water pump of which a water outlet is communicated with the simulated bore through a fracture pipeline; the sealing system comprises a sample cylinder sealing device and an experimental cylinder sealing device; and the monitoring system comprises an acoustic emission sensor arranged on an external wall of the sample cylinder. By the coal and rock bore hydraulic fracture experimental apparatus, a simulated experiment can be performed in a laboratory to investigate the change rules of crack initiation, expansion and extension in the hydraulic fracture process of a coal mine underground coal seam bore, and know a crack extending direction so as to guide field fracture; therefore, the fracture effect is greatly improved.

The invention relates to a gas drainage method combining surface and underground fracturing and permeability improvement, and the method comprises the following steps: building underground large-diameter directional long boreholes in a coal reservoir or the top and bottom plates thereof under a coal mine by using a drilling machine; then building pressure relief holes in a coal bed having an appropriate distance with the large-diameter directional long boreholes; building vertical wells communicated with an underground large-diameter directional long borehole filed or nearby roadways thereof from the ground to the underground; firmly connecting large ground fracturing equipment, a ground vertical well shaft and the underground large-diameter directional long boreholes by using high pressure pipelines; carrying out fracturing on each underground large-diameter directional long borehole by using the large ground fracturing equipment to form a three-dimensional fracture network; discharging water in the underground large-diameter directional long boreholes and then carrying out continuous pressure extraction on fracturing holes and the pressure relief holes; and quickly extracting out the coal bed gas through negative pressure by using the three-dimensional fracture network. According to the invention, the coal bed gas can be extracted out quickly with high efficiency by using the three-dimensional fracture network and negative pressure, thereby providing a technical guarantee for safe and high-efficiency production of mines; and the method has the advantage of wide application prospect.

A gas extraction and drilling cooperative drilling and protecting integrated system for soft coal seams and process belong to soft coal seam cooperative drilling and protecting systems and process. The gas extraction and drilling cooperative drilling and protecting integrated system mainly consists of a control table, a hydraulic pump station, an air compressor, a feeding device, a drill stem, a hole protecting tube, a drill bit and the like. The hole protecting tube is located in the drill stem, and the hole protecting tube and the drill stem are synchronously connected and drill cooperatively. The depth of a drilled hole is equal to the length of the hole protecting tube. Finally, the hole protecting tube penetrates through the drill bit, and the drill stem is withdrawn while the hole protecting tube is remained in the hole to realize functions of supporting a hole wall and extracting gas. The system and the process are convenient in operation, the hole protecting tube and the drill stem realize cooperative drilling and protecting, the hole protecting tube is easy to be remained in the drilled hole, problems that the hole collapses and the hole protecting tube is difficult to be fed to the drilled hole can be resolved, the hole protecting depth is high, the hole wall can be supported more effectively, deformation and collapse are prevented, accordingly high gas extraction concentration and flow of the soft coal seams are guaranteed, and the gas extraction and drilling cooperative drilling and protecting integrated system for soft coal seams and the process are particularly applicable to quite soft coal seams with the value of the firmness factor f smaller than 0,3.

The invention relates to a directional hydraulic pressing penetration, permeability increase and outburst elimination method of a guide groove, which comprises the steps of (1) constructing a guide groove drill or the guide groove drill and control drills in a coal seam; (2) forming a guide groove in the guide groove drill in advance; (3) utilizing the guide groove drill or the control drills to perform hydraulic fractures, utilizing the guide groove and the control drills to perform directional control on the hydraulic fractures, enabling the coal body between the guide groove drill or the guide groove drill and the control drills to be pressed into penetration, forming multiple fractures among drills, and enabling a large amount of nickings to be brought out through the high-pressure water; and (4) after the fractures finish, enabling all the drills to be sealed and accessed into a drainage system, and beginning extraction. By means of the method, the number of pressing penetration of drills can be increased by 50%, the pressure relief scope of the coal seam is increased by over one time, the permeability of the coal seam is remarkably improved, gas extraction is increased by more than four times, measure drills can be reduced by about 60%, fore-pumping time is effectively reduced, area outburst elimination is achieved, and gas hazards can be reduced to the largest extent.

The invention discloses a three-dimensional simulation experiment table which mines coal and gas together. The experiment table includes a box body. The box body is provided with a pressurizing device used for uniformly loading on the rocks in the box body to realize mine pressure simulation. The experiment table is also provided with a coal mining device which can move at the bottom part of the box body to simulate the process of cutting coals by a coal mining machine. The box body is also provided with an air inlet device and a plurality of gas detecting sensors used for the simulation experiment of the gas to move in a porous medium in a mining field during the process of simulating the coal bed mining and the desorption and moving rules of the gas in the coal rock bodies that are relieved from pressure, deformed and crashed during the process of comprehensively researching the coal bed mining to work out the space-time evolvement and distribution rules of the coupling between the gas moving and the coal rock body cranny. Then the simulation research and mining scheme design on mining coal and gas together are carried out according to the researching result.

The invention discloses a method for extracting gas from a separation layer below an overlying strata, draining water and grouting through a combined drill hole and belongs to a mine disaster prevention method. The method for extracting gas from the separation layer below the overlying strata, draining water and grouting through the combined drill hole includes that installing a drill site at a transportation roadway of a preparatory work face adjacent to a coalface, constructing the combined drill hole in the part about to generate the separation layer below the overlying strata above the gob of the coalface in a mode of keeping away from a caving zone, wherein the combined drill hole is composed of an inside gas extraction pipe and a water draining-grouting pipe; after the separation layer is generated, preventing the mine disaster according to the stages that firstly, draining water from the separation layer through the combined drill hole; secondly, after the gas is gathered in the separation layer after the water in the separation layer is emptied, using the primary combined drill hole to extract the gas from the separation layer; finally, after the water and gas are completely drained and extracted from the separation layer, filling cement paste to the separation layer through the primary combined drill hole. The method for extracting gas from the separation layer below the overlying strata, draining water and grouting through the combined drill hole is capable of solving the mine disasters of water bursting in mine, gas outburst (gas emission), rock burst, surface subsidence and the like through the combined drill hole, the separation layer water and gas extraction rate is high, and the grouting effect is good.