China University of Mining and Technology

State Grid Corporation of China

Wuxi Electric Power Company of Jiangsu Electric Power Corporation

Ting Liu

Baiquan Lin

Chuanjie Zhu

Fazhi Yan

Hao Yao

Quanle Zou

Chang Guo

Jia Kong

Wei Yang

Rui Wang

Tong Liu

He Li

Yidu Hong

Zhanbo Huang

Kai Liu

Zheng Wang

Xiangliang Zhang

Hongjun Chen

Yidou Hong

Haiping Shen

Yihan Wang

Boquan Lin

Liping Huang

Xu Weng

Wenjun Jiang

Pan Tang

Bai Quan Lin

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.

Permeability enhancement method for coalbed methane wells by using electric pulse detonation fracturing technology

A method for constructing networked preferential gas migration pathways and diverting and extracting gas. The method proposes that a fracture generation hole, a fracture guidance and development hole, a lateral rupture hole, and a fracture connection hole are respectively constructed in a roof in roadways on two sides of a working face in advance of an advance stress change area. Artificial guided fractures are actively constructed and formed inside the hard roof. Under a mining-induced stress effect, the artificial guided fractures and mining-induced fractures intersect with and are connected to each other to form networked preferential gas migration pathways. Meanwhile, boreholes for artificial guided fractures accelerate roof fracturing to form a rupture bed separation fracture area in a roof. Gas flows and migrates in a timely and efficient manner along networked fracture pathways and concentrates in the rupture bed separation fracture area in the roof.

Method for constructing networked preferential gas migration pathways and diverting and extracting gas

A method for stepwise construction of a preferential gas migration pathway at a stope in a coal seam. First, a gas migration pathway is preliminarily formed at a stope depending on a mining effect of mining in a first mined seam. construction and stabilization method of gob-side entry retaining in deep strata, and a method of manual-guided pre-fracturing boreholes are then used to perform active construction respectively in external space and the outside of coal-rock mass to form preferential gas migration pathways. Eventually, under the effect of mining-induced stress, a system of preferential gas migration pathways connected to each other at the stope is further formed.

Method for stepwise construction of preferential gas migration pathway at stope in coal seam

The present invention relates to a method for sorting and utilizing coal and rock for a coal and rock combined mining face, and is especially applicable to the sorting and utilization of coal and rock mined from a coal and rock combined mining face when an extremely thin coal seam is used as a protective layer in combined mining of multiple coal seams. Underground gangue transport, storage and filling systems are directly established underground to convey a large amount of coal and gangue mined from the coal and rock mining face to an underground sorting and washing chamber for efficient separation of the coal and the gangue, sorted gangue is crushed and then filled in a mined-out area of a protected layer, thus realizing the environment-friendly cut and fill mining of the protective layer while the gangue is not lifted, and effectively preventing the ground subsidence caused by combined mining of multiple coal seams; sorted middlings are conveyed to a gangue power plant on the ground for power generation through a main conveying system, so that the pressure on mine coal quality is alleviated when benefits are created in the power plant, and thus the average ash content of commercial coal is reduced, and the selling price is increased. The method provided by the invention realizes the efficient utilization of coal and rock while realizing the efficient separation of coal and gangue, and has remarkable economic and social benefits and excellent promotional value.

Method of sorting and utilizing coal and rock for coal and rock combined mining face

A gas extraction method in which high energy gas fracturing technology is used to form a fracture network in a thermal injection borehole. Then high-pressure, cyclically temperature-changing steam is injected into the borehole using a spinning oscillating-pulse jet nozzle to form oscillating superheated steam, alternatingly impacting and heating the coal body. The high energy gas forms a fracture network that provides channels for passage of the superheated steam, while oscillating changes in steam temperature and pressure also promote crack propagation and perforation of the coal body; the combined effect of alternation of the two enhances gas desorption and extraction efficiency.

Method for gas extraction alternating oscillating pulse high energy gas extraction with thermal injection

A method for combining integrated drilling, flushing and slotting with thermal injection to enhance coalbed gas extraction, applicable to managing gas extraction from microporous, low-permeability, high-adsorption coalbed areas. A gas extraction borehole is drilled within a certain distance of a predetermined drilling, flushing and slotting borehole, and, once sealed, is used for gas extraction. An integrated drilling, flushing and slotting drill bit is used to sink the borehole, which is then sealed. Concentration variation in the gas extraction borehole is monitored in real time, and when concentration is below 30%, borehole is opened and high-temperature steam is injected by means of a steam generator, after which the borehole is again closed. Drilling a drilling, flushing and slotting borehole increases pressure relief space and the surface of exposed coal, relieves stress on the coal body, and increases gas permeability of the coalbed, while the injection of high-temperature steam promotes gas desorption in the coal body, promotes crack propagation around the borehole, and increases channels for gas flow, thus achieving highly efficient extraction of gas from the coalbed.

Method for integrated drilling, flushing, slotting and thermal injection for coalbed gas extraction

An electric vehicle for routing inspection of power transmission lines, includes a body; a running mechanism mounted to the body, comprising a front wheel and a rear wheel connected by a cross beam and rolling on the cable; an obstacle sensor and a cam rotatably mounted to the cross beam, the cam rotating to roll onto the cable after an obstacle is detected on the cable such that the front wheel is raised to a position above the cable, and the cam continuing rolling on the cable after the front wheel passes the obstacle such that the front portion of the cross beam falls back downwards and the front wheel then falls back onto the cable, a hanging seat rotatably hanging to the body and a control device at least partially disposed in the hanging seat and comprising a braking device.

Electric vehicle for routing inspection of power transmission lines

A method for combining integrated drilling and slotting with oscillating thermal injection to enhance coalbed gas extraction, applicable to managing gas extraction from microporous, low-permeability, high-adsorption coal seam areas. A number of slots are formed within a thermal injection/extraction borehole by means of integrated drilling and slotting technology; a steam generator, is then used to three high-pressure, cyclically temperature-changing steam into said borehole; the steam passing through a spinning, oscillating-pulse jet nozzle forms an oscillating superheated steam, heating the coal body. The present method overcomes the limitations of simple permeability-increasing techniques, the slotting by means of hydraulic. pressure significantly increasing the pressure relief range of a single borehole and forming a fracture network that provides channels for passage of the superheated steam, while oscillating variation in steam temperature and pressure also promote crack propagation and perforation of the coal body; the combined effect of the two enhances the efficiency of gas desorption and extraction.

Method for integrated drilling, slotting and oscillating thermal injection for coal seam gas extraction

A method for permeability improvement for a downhole coal seam by directional fracturing with pulsed detonation waves, which is applicable to gas control in coal seam areas with high gas concentration and low air permeability. The permeability improvement method is as follows: first, drilling a pulsed detonation borehole and pulsed detonation guide boreholes from a coal roadway to a coal seam respectively; then, pushing a positive electrode connected to a positive output side of an explosion-proof high-voltage electrical pulse generator to the bottom of the pulsed detonation borehole and pushing a negative electrode connected to a negative output side of the explosion-proof high-voltage electrical pulse generator to the bottom of the pulsed detonation guide borehole; connecting the pulsed detonation borehole and the pulsed detonation guide boreholes to an extraction pipeline for gas extraction, after electrical pulsed detonation fracturing for the coal seam is carried out. The method disclosed in the present invention utilizes the high instantaneous energy provided by electrical pulsed detonation waves to fracture a coal mass, so as to form a fissure network in the coal mass between the pulsed detonation borehole and the pulsed detonation guide boreholes; thus, the air permeability coefficient of the coal mass can be increased by 200-400 times, the effective influence scope of gas extraction of a single borehole for gas extraction can be enlarged by 3-4 times, the extracted gas volume from the borehole can be increased by 3-8 times, and the coal seam gas pre-extraction time can be shortened effectively.

Downhole coal seam pulse detonation wave directional fracturing permeability-increasing method

Growing community of inventors

Jiangsu, China

Ting Liu