In a method, a gyroscope and an endoscopic camera are first used to investigate coal-seam strike trend, coal-seam dip trend, and coal-seam thickness data of a to-be-extracted area. According to gas extraction standard requirements of a to-be-extracted area, boreholes are then designed and constructed, and trajectories of boreholes are tracked to obtain a correspondence relationship between designed borehole parameters and actual borehole trajectory parameters. Next, drilling parameters are adjusted according to the correspondence relationship between the designed borehole parameters and the actual borehole parameters to construct boreholes at predetermined borehole locations. Subsequently, the boreholes are connected to an extraction pipeline, and gas extraction flow rates and gas extraction amounts per meter of the boreholes are observed. Eventually, other boreholes are designed and constructed according to the adjusted borehole construction parameters and extraction data. After being constructed, the boreholes are connected to perform gas extraction.

A ground wellhole dedicated protective pipe, disposed inside a ground wellhole for gas extraction of a mining-induced area, includes a casing, and a chain inside the casing and slidable relative to the casing. The chain includes a chain formed by a plurality of chain drums through serial connection, and a detachable connecting piece connecting between chains. A plurality of air holes is opened in the chain drum along an axial direction of the chain drum.

A permeability enhancement method for coalbed methane wells by using electric pulse detonation fracturing technology is applicable to exploitation of coalbed methane wells in coal beds with low permeability. Firstly, a positive electrode coalbed methane wellbore and a negative electrode coalbed methane wellbore are constructed from the ground surface to a coal bed. A fixed platform installed with a positive electrode and a high-voltage pulse device are placed, by using a derrick, downwards to a predetermined permeability enhancement portion of the coal bed in the positive electrode coalbed methane wellbore, and another fixed platform installed with a negative electrode is placed, by using a derrick, downwards to a predetermined permeability enhancement portion of the coal bed in the negative electrode coalbed methane wellbore. The coal bed between the positive electrode and the negative electrode is broken down by using a high voltage, and coalbed methane extraction is carried out in the positive electrode coalbed methane wellbore and the negative electrode coalbed methane wellbore. A large amount of energy produced by high-voltage electric pulse directly acts on the coal reservoir to form a plasma channel in the coal bed between the positive electrode and the negative electrode. The large amount of energy instantly passes through the plasma channel, and the produced high-temperature thermal expansion force and shock waves act on the coal bed, such that the number of cracks in the coal bed is effectively increased and a favorable condition is created for flowing of coalbed methane.

The present invention comprises a remote gas monitoring system (RGMS) which improves soil-gas monitoring and data management tasks at landfills and other impacted sites while reducing errors in data collection. The remote gas monitoring system allows for continuous monitoring of landfill soil-gas composition and more efficient and cost-effective operation of a landfill flare system. The invention also comprises a method of controlling the operation of a landfill flare by signaling the flare to begin and cease operation based on predetermined threshold landfill gas concentrations.

A system for extracting gas from a tectonically-deformed coal seam in-situ by depressurizing a horizontal well cavity is provided. A horizontal well is constructed by a horizontal well drilling and reaming subsystem and adjoins a vertical well to form a U-shaped well, and a horizontal section of the horizontal well is reamed to enlarge hole diameter. A horizontal well hole-collapse cavity-construction depressurization excitation subsystem performs pressure-pulse excitation and stress release on the horizontal well of tectonically-deformed coal bed methane, and hydraulically displaces a coal-liquid-gas mixture such that the mixture is conveyed towards a vertical well section along a depressurizing space. A product lifting subsystem further pulverizes the coal and lifts the mixture towards a wellhead of a vertical well. A gas-liquid-solid separation subsystem separates the coal, liquid and gas. A monitoring and control subsystem detects and controls the operation conditions and the execution processes of technical equipment in real time.

An integrated hole sealing, device includes a capsule plug, an outer capsule having a first hole site, an inner capsule having a second hole site, a capsule water injection pipe, a borehole water injection pipe and a tapered plug. Two ends of the outer capsule and the inner capsule are respectively fixed on the capsule plug and the tapered plug. The capsule plug, the tapered plug, the outer capsule and the inner capsule form a closed hollow cylindrical cavity. A middle part of the inner capsule is a hollow pipeline, and two ends thereof respectively correspond to the first and second hole sites. The borehole water injection pipe passes through the hollow cylindrical cavity. A part, located in the hollow cylindrical cavity, of the borehole water injection pipe is telescopically wound outside the inner capsule. The capsule water injection pipe passes through the capsule plug and extends into the hollow cylindrical cavity.

A multi-stage combustion impact wave coal mass cracking and heat injection alternating intensified gas extracting method is provided. A large amount of N.sub.2 or CO.sub.2 is injected into a drill hole by a heat injection and gas injection extracting pipe and by a high-pressure gas cylinder and a reducing valve, then a certain amount of methane and dry air are injected into a high-temperature and high-pressure combustion chamber by the high-pressure gas cylinder and the reducing valve, to be mixed and combusted to form high-temperature and high-pressure impact wave. High-temperature vapour is injected into the drill holes by the heat injection and gas injection extracting pipe to promote desorption of the coal masses.

A multi-stage combustion impact wave coal mass cracking and heat injection alternating intensified gas extracting method is provided. A large amount of N.sub.2 or CO.sub.2 is injected into a drill hole by a heat injection and gas injection extracting pipe and by a high-pressure gas cylinder and a reducing valve, then a certain amount of methane and dry air are injected into a high-temperature and high-pressure combustion chamber by the high-pressure gas cylinder and the reducing valve, to be mixed and combusted to form high-temperature and high-pressure impact wave. High-temperature vapour is injected into the drill holes by the heat injection and gas injection extracting pipe to promote desorption of the coal masses.

The present invention relates to a ducting system (100) for conveying a flow of a gaseous feed (110) comprising a combustible component from an inlet to at least one combustion module (12), the ducting system (100) utilising a combination of a sensor (C0) for measuring the concentration of the combustible component in the gaseous feed (110), a flame detector (F0, F1, F2, F3, . . . , Fn) a shut-off valve (6) and a flame arrestor (5) located in a flow path of the gaseous feed upstream of the shut-off valve (6) such that a measurement of a concentration of combustible material in the gaseous feed over a specified concentration by the sensor (CO) causes the shut-off valve (6) to be configured to the closed position for preventing flow of a gaseous feed comprising a combustible mixture of the combustible component from reaching an ignition source and/or detection of flame by the flame detector (F0, F1, F2, F3, . . . , Fn) causes shut-off valve (6) to be configured to the closed position for attenuating propagation of a flame towards the inlet.

The present invention relates to a ducting system (100) for conveying a flow of a gaseous feed (110) comprising a combustible component from an inlet to at least one combustion module (12), the ducting system (100) utilising a combination of a sensor (C0) for measuring the concentration of the combustible component in the gaseous feed (110), a flame detector (F0, F1, F2, F3, . . . , Fn) a shut-off valve (6) and a flame arrestor (5) located in a flow path of the gaseous feed upstream of the shut-off valve (6) such that a measurement of a concentration of combustible material in the gaseous feed over a specified concentration by the sensor (CO) causes the shut-off valve (6) to be configured to the closed position for preventing flow of a gaseous feed comprising a combustible mixture of the combustible component from reaching an ignition source and/or detection of flame by the flame detector (F0, F1, F2, F3, . . . , Fn) causes shut-off valve (6) to be configured to the closed position for attenuating propagation of a flame towards the inlet.