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1.发明申请公开(公告)号：US20180209255A1
公开(公告)日：2018-07-26
申请号：US15322457
申请日：2015-12-22
发明人： Baiquan LIN , Chang GUO , Quanle ZOU , Ting LIU , Chuanjie ZHU , Jia KONG , Fazhi YAN , Hao YAO , Yidu HONG
CPC分类号： E21B43/24 , E21B7/18 , E21B41/0078 , E21B43/26 , E21F7/00
摘要： 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.
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2.发明申请公开(公告)号：US20200240245A1
公开(公告)日：2020-07-30
申请号：US15767141
申请日：2017-06-26
发明人： Bai quan LIN , Yihan WANG , Fazhi YAN , Xiangliang ZHANG
摘要： A blockage removal and permeability enhancement method for coalbed methane wells by using electric pulses is applicable to high-efficiency exploitation of coalbed methane wells. The blockage removal and permeability enhancement method includes: constructing a positive electrode coalbed methane wellbore and a negative electrode coalbed methane wellbore from the ground to a coal bed; when the gas yield declines because cracks in the coal bed are closed gradually or blocked by granular impurities as coalbed methane extraction goes on after hydrofracturing, injecting a conductive ion solution into the positive electrode coalbed methane wellbore to fill the coal bed between the positive electrode coalbed methane wellbore and the negative electrode coalbed methane wellbore with the conductive ion solution; placing a positive electrode and a negative electrode downwards to predetermined permeability enhancement portions of the coal bed in the positive electrode coalbed methane wellbore and the negative electrode coalbed methane wellbore respectively; and breaking down, by using high-voltage electric pulses discharge, the coal bed filled with the conductive plasma solution between the positive electrode and the negative electrode, where shock waves generated from a large amount of energy act on the coal bed to cause the closed cracks in the coal bed to be opened again and extend and to remove the granules blocking the cracks, such that the number of the cracks in the coal bed is effectively increased and crack connectivity is improved.
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3.发明申请公开(公告)号：US20200240246A1
公开(公告)日：2020-07-30
申请号：US15767880
申请日：2016-12-15
发明人： Bai quan LIN , Fazhi YAN , Xiangliang ZHANG , Jia KONG , Ting LIU , Chuanjie ZHU
摘要： 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.
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4.发明申请公开(公告)号：US20180112505A1
公开(公告)日：2018-04-26
申请号：US15325662
申请日：2015-12-28
发明人： Baiquan LIN , Fazhi YAN , Chuanjie ZHU , Chang GUO , Quanle ZOU , Ting LIU , Yidu HONG , Hao YAO
摘要： 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.
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