Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 28 of 28
Full-Text Articles in Mining Engineering
A Drilling-Punching-Hole Protection Integrated Hydraulic Caving Technology For Broken Soft And Low-Permeability Coal Seams, Yao Ningping, Hao Shijun, Zhang Jinbao, Wei Hongchao, Nie Chao
A Drilling-Punching-Hole Protection Integrated Hydraulic Caving Technology For Broken Soft And Low-Permeability Coal Seams, Yao Ningping, Hao Shijun, Zhang Jinbao, Wei Hongchao, Nie Chao
Coal Geology & Exploration
Objective and Method For broken soft and low-permeability coal seams, gas drainage achieved through permeability enhancement and pressure relief by cross-seam hydraulic caving in coal seam floor faces problems including serious borehole collapse in the drilled coal seam intervals, low construction efficiency, and poor gas drainage performance. To address these problems, this study proposed a high-efficiency drilling-punching-hole protection integrated gas drainage technology, which enabled hydraulic caving, permeability enhancement, and pressure relief. Furthermore, this study developed a drilling-punching-hole protection integrated caving device. Through laboratory experiments conducted under pressure conversion and central channels equipped with controllable opening/closing mechanisms, this study selected the …
A Phase Transition-Induced Fracturing Permeability Enhancement Technology Using Carbon Dioxide Capsules For Low-Permeability Coal Seams And Its Application, Li Mao, Fan Xinchuan, Fu Hui
A Phase Transition-Induced Fracturing Permeability Enhancement Technology Using Carbon Dioxide Capsules For Low-Permeability Coal Seams And Its Application, Li Mao, Fan Xinchuan, Fu Hui
Coal Geology & Exploration
Objective and Methods To address engineering challenges like high gas content, high pressure, and low drainage efficiency in the mining of low-permeability coal seams, this study developed a phase transition-induced fracturing and permeability enhancement technology using carbon dioxide (CO2) capsules for low-permeability coal seams. This technology leverages the feature that CO2 transitions into the supercritical state under high pressure. A capsule encapsulating critical CO2 is placed into a conduit, which is then placed within a coal seam. Subsequently, phase transition-induced blasting is triggered using a heating blasting start device. Consequently, liquid CO2 vaporizes rapidly and …
Engineering Practice Of Advance Gas Control For Crushed Soft Coal Seams Through Directional Fracturing Using A Long Borehole In The Coal Seam Roof, Jia Bingyi, Li Shugang, Chen Dongdong, Zhang Qun
Engineering Practice Of Advance Gas Control For Crushed Soft Coal Seams Through Directional Fracturing Using A Long Borehole In The Coal Seam Roof, Jia Bingyi, Li Shugang, Chen Dongdong, Zhang Qun
Coal Geology & Exploration
Objective and Methods The crushed soft coal seams susceptible to intense coal and gas outbursts exhibit high gas content and pressure. Consequently, during borehole drilling for regional gas pre-drainage in such coal seams, high blowout intensity is prone to cause gas overrun and low drilling efficiency. To accelerate its development, this study analyzed the status and adaptability of existing technologies for regional advance gas drainage and pressure relief, as well as the fracture propagation characteristics of coal seam roofs during indirect fracturing using boreholes near the roofs. Accordingly, this study proposed an advance gas drainage and pressure relief technology for …
A Deep Learning-Based Method For The Intelligent Identification Of The Quantity Of Coals Flushed Out During Borehole Hydraulic Flushing, Li Xiaojun, Zhao Mingyang, Li Miao
A Deep Learning-Based Method For The Intelligent Identification Of The Quantity Of Coals Flushed Out During Borehole Hydraulic Flushing, Li Xiaojun, Zhao Mingyang, Li Miao
Coal Geology & Exploration
Objective Given the inaccurate and low-efficiency manual statistics of the quantity of coals flushed out during borehole hydraulic flushing, this study proposed an intelligent identification method that combines YOLOv8n, ResNet34, and PP-OCRv4 algorithms. Methods First, the first-level detection was completed using the YOLOv8n algorithm, which, combined with the ResNet34 and PP-OCRv4 algorithms via parallel cascade, was then employed to conduct second-level processing. Through the above processing and in combination with the method for classification status discrimination based on tracking frame numbers, the framework of an algorithm for automatically calculating the quantity of coals flushed out was established. Subsequently, the deformable …
Gas Drainage And Utilization In Coal Mines In China: History, Technological Advances, And Prospects, Li Guofu, Li Chao, Zhang Bichuan, Xu Yun, Wang Zheng, Zhou Xianjun
Gas Drainage And Utilization In Coal Mines In China: History, Technological Advances, And Prospects, Li Guofu, Li Chao, Zhang Bichuan, Xu Yun, Wang Zheng, Zhou Xianjun
Coal Geology & Exploration
Objective and Methods To promote the research and application of gas drainage and utilization technologies for coal mines, this study systematically summarizes the history of China’s coal mines transitioning from gas pumping to gas drainage, the accurate and effective gas drainage technologies for typical coal mining areas in China, and the latest applications of technologies related to safe gas gathering and transportation, as well as the utilization of gas with a full range of concentrations. This study aims to provide a reference for accelerating the advancement in gas drainage and utilization technologies for coal mines, achieving methane emission reduction, and …
Research Progress On Variation Pattern And Monitoring Control Technology Of Negative Pressure For Gas Drainage In Directional Long Borehole, Li Quanxin, Cheng Zhuoer, Fang Jun, Mou Quanbin, Liu Fei, Cong Lin
Research Progress On Variation Pattern And Monitoring Control Technology Of Negative Pressure For Gas Drainage In Directional Long Borehole, Li Quanxin, Cheng Zhuoer, Fang Jun, Mou Quanbin, Liu Fei, Cong Lin
Coal Geology & Exploration
Significance Near-horizontal directional long borehole is an important technical approach and effective means for preventing and controlling the gas disasters of coal mine. Negative pressure is an important factor affecting the gas drainage effect of directional long borehole. Advances Herein, the research progress on gas drainage through near-horizontal directional long borehole was systematically summarized from three aspects: the attenuation mechanism and distribution law of negative pressure in the borehole, gas drainage parameter monitoring technology, and intelligent control system for gas drainage. Regarding the attenuation mechanism and distribution law of negative pressure in the borehole, the basic theoretical research results concerning …
Coal Permeability Enhancement Via Cyclic Percussion Using Low-Temperature Liquid Co2 And High-Temperature Water Vapor And Simulations Of Resultant Gas Drainage Performance, Qin Lei, Wang Ping, School Of Civil And Resource Engineering, University Of Science And Technology Beijing, Beijing 100083, China Shugang, Wang Hui, Liu Pengfei, Li Jiawei, Lin Haifei
Coal Permeability Enhancement Via Cyclic Percussion Using Low-Temperature Liquid Co2 And High-Temperature Water Vapor And Simulations Of Resultant Gas Drainage Performance, Qin Lei, Wang Ping, School Of Civil And Resource Engineering, University Of Science And Technology Beijing, Beijing 100083, China Shugang, Wang Hui, Liu Pengfei, Li Jiawei, Lin Haifei
Coal Geology & Exploration
Objective In the application of the coal seam permeability enhancement technique based on liquid CO2, pore water in coal seams freezes due to low temperatures, blocking pathways for gas migration. Hence, this study developed a technique for coal permeability enhancement through cyclic percussion using low-temperature liquid CO2 and high-temperature water vapor (also referred to as the cyclic cold and hot percussion). Methods This study delved into the permeability evolutionary patterns of coals under cyclic cold and hot percussion using a low-field nuclear magnetic resonance (NMR) spectrometer, an automatic coal permeability tester, a contact angle tester, and 3D …
Key Technology And Practice Of Deep Borehole Pneumatic Directional Drilling In Broken-Soft Coal Seam In Yangquan Mining Area, Liu Fei, Li Quanxin, Fang Jun, Liu Jianlin, Yang Weifeng, Chu Zhiwei, Zhao Jianguo, Wang Siyi
Key Technology And Practice Of Deep Borehole Pneumatic Directional Drilling In Broken-Soft Coal Seam In Yangquan Mining Area, Liu Fei, Li Quanxin, Fang Jun, Liu Jianlin, Yang Weifeng, Chu Zhiwei, Zhao Jianguo, Wang Siyi
Coal Geology & Exploration
Objective In response to the need for precise, proactive, and regional management of gas in the broken-soft coal seam of the Yangquan Mining Area, a technical scheme utilizing pneumatic directional drilling for pre-drainage boreholes was proposed. Methods Based on the analysis of the technical challenges in pneumatic directional drilling, a series of technologies suitable for the broken-soft coal seam in the Yangquan Mining Area were developed. These include stable operation technology for pneumatic downhole motors, precise control technology for drilling boreholes, efficient deep-hole slag discharge technology, and pneumatic milling and salvage technology. The pneumatic directional drilling equipment was optimized, and …
Characteristics Of Gas Bursting And Application Of Layered Cutting Drilling In Outburst Coal Seam, Wang Yonglong, Zhao Aoqi, Yu Zaijiang, Wang Zhenfeng, Liu Xiao, Ma Denghui, Zhang Hui, Liu Chun
Characteristics Of Gas Bursting And Application Of Layered Cutting Drilling In Outburst Coal Seam, Wang Yonglong, Zhao Aoqi, Yu Zaijiang, Wang Zhenfeng, Liu Xiao, Ma Denghui, Zhang Hui, Liu Chun
Coal Geology & Exploration
Objective The overlimit gas bursting in the drilling process of outburst coal seam is a safety hazard that threatens the efficient production of the mine. The layered cutting drilling method helps to weaken the burst gas pressure in the borehole, but the characteristics of gas release around the trapezoidal borehole formed by layered cutting are unknown, which limits the structural design and application effect of the layered cutting drilling tool. Methods Herein, study was conducted based on the layered cutting boreholes with different layer spacing and layer thickness difference. Specifically, a mathematical model was established to analyze the gas flow …
Pneumatic Directional Drilling Technology And Equipment For Broken-Soft Coal Seams In Underground Coal Mines, Tian Hongliang, Zhang Jinbao, Wang Li, Fang Jun, Wang Jianqiang
Pneumatic Directional Drilling Technology And Equipment For Broken-Soft Coal Seams In Underground Coal Mines, Tian Hongliang, Zhang Jinbao, Wang Li, Fang Jun, Wang Jianqiang
Coal Geology & Exploration
[Objective] The geological conditions of coal seams in China are complex, with a wide distribution of broken-soft coal seams, and a large number of wells have the problems of high gas and coal-gas outburst. Currently, borehole gas drainage is an effective measure for preventing and controlling the gas disasters. [Methods] In response to the problems of uncontrollable drilling trajectory, shallow drilling depth, large blind spots of drainage in conventional rotary drilling process of broken-soft coal seams, as well as multiple stuck drilling accidents, great difficulty in drilling and low drilling efficiency in conventional directional drilling processes, the development history and …
Investigation And Comprehensive Utilization Of Resources In Closed Coal Mines In Anhui Province, China, Liu Feiyue, Chen Wanyun, Yang Ke, Duan Minke, Liu Qinjie, Yang Lingyue
Investigation And Comprehensive Utilization Of Resources In Closed Coal Mines In Anhui Province, China, Liu Feiyue, Chen Wanyun, Yang Ke, Duan Minke, Liu Qinjie, Yang Lingyue
Coal Geology & Exploration
[Objevtive] With the continuously intensive exploitation of coal resources and the structural reform of energy supply, many coal mines in Anhui Province have been closed due to resource depletion or backward production capacity. However, the closed coal mines still host resources such as underground spaces, residual coals, gas, mine water, land, and infrastructure equipment. Hence, reutilizing resources in closed coal mines holds significant engineering value and economic benefits. [Methods] Based on the general information and reutilization status of 59 coal mines in Anhui Province that have been closed since 2013, this study analyzed the distribution characteristics, residual resources, and reutilization …
Weight And Resistance Reduction Mechanism Of Drilling Rods For Drilling In Soft Coal Seam And Its Application, Wang Yonglong, Guo Jiakuan, Yu Zaijiang, Du Kang, Sun Yuning
Weight And Resistance Reduction Mechanism Of Drilling Rods For Drilling In Soft Coal Seam And Its Application, Wang Yonglong, Guo Jiakuan, Yu Zaijiang, Du Kang, Sun Yuning
Coal Geology & Exploration
Gas drainage boreholes during construction is a necessary means to control gas hazards. In response to the issues such as high drilling resistance, low drilling efficiency, and high labor intensity caused by the significant self-weight of the drilling rod in drilling into the soft coal seams, a research approach of reducing the self-weight and lowering the drilling resistance by optimizing the drilling rod structure was proposed. Thus, a four-winged concave grooved drilling rod was designed to address both of its advancing resistance and rotating torque losses. Meanwhile, a drilling resistance model for the drilling rod was established. On this basis, …
Exploring Dynamic Parameters And Tooth Structure Of Self-Propelled Borehole Repairing Drill Bits, Liu Yong, Li Yang, Wei Jianping, Yuan Yongwang, Dai Shuo, Li Linyu
Exploring Dynamic Parameters And Tooth Structure Of Self-Propelled Borehole Repairing Drill Bits, Liu Yong, Li Yang, Wei Jianping, Yuan Yongwang, Dai Shuo, Li Linyu
Coal Geology & Exploration
Self-propelled borehole repairing drill bits provide an effective technique for repairing long boreholes that have failed. In order to further improve the borehole repair speed and gas drainage efficiency, based on the theory of jet recoil, the relationship between the jet recoil force and nozzle parameters was analyzed, and a theoretical model was established for rotational mechanics of self-propelled borehole repairing drill bits. Subsequently, the coal-breaking processes of drill bits with different tooth structures were simulated using LS-DYNA, the failure modes in coal mass broken by cutting teeth and the rules of variation in the volume of coal broken by …
Deformation And Collapse Patterns Of Gas Drainage Boreholes And A Precise Monitoring Technology, Xiao Peng, Huang Xiaosheng, Liu Xiaoxiao, Li Bingkun, Chen Liping, Chen Zixi, Zhang Chao, Cheng Renhui, Zhao Yajie
Deformation And Collapse Patterns Of Gas Drainage Boreholes And A Precise Monitoring Technology, Xiao Peng, Huang Xiaosheng, Liu Xiaoxiao, Li Bingkun, Chen Liping, Chen Zixi, Zhang Chao, Cheng Renhui, Zhao Yajie
Coal Geology & Exploration
This study aims to promote the precise and intelligent monitoring of gas drainage boreholes. In the engineering background of a coal mine in Shanxi Province, this study conducted simulation experiments on the plugging of gas extraction boreholes under varying particle size ratios of simulated coal samples using distributed optical fiber monitoring and the Brillouin Optical Time-Domain Analysis (BOTDA). Then, this study established a mathematical model for calculating the borehole plugging rate of the test mine, revealing the deformation and collapse patterns of gas drainage boreholes. Furthermore, this study proposed a precise in-situ monitoring technology for the gas drainage boreholes in …
A Method For Identifying Faults Within Mining Faces Based On Spatial Statistics, Feng Yajie, Wen Guangchao, Wu Bingjie, Hu Zudong
A Method For Identifying Faults Within Mining Faces Based On Spatial Statistics, Feng Yajie, Wen Guangchao, Wu Bingjie, Hu Zudong
Coal Geology & Exploration
Minor faults within mining faces of coal mines severely affect gas drainage and coal seam mining. Accurately identifying parameters such as positions, throws, and attitudes of these faults is of great significance for the safe production of coal mines. To effectively reduce gas emissions, prevent gas explosions, and exploit and utilize gas resources, many gas drainage holes have been drilled during the construction of coal mines, providing favorable engineering conditions for identifying minor faults within coal seams. Compared with the conventional fault identification methods, which rely on the expertise of geologists, the identification model based on mathematical statistics and space …
Study On Factors Influencing The Self-Propelling Capacity Of Self-Propelled Water Jet Drill Bits, Liu Yong, Dai Shuo, Wei Jianping, Zhang Hongtu, Yuan Yongwang, Guo Xinhui, Gao Yingjun
Study On Factors Influencing The Self-Propelling Capacity Of Self-Propelled Water Jet Drill Bits, Liu Yong, Dai Shuo, Wei Jianping, Zhang Hongtu, Yuan Yongwang, Guo Xinhui, Gao Yingjun
Coal Geology & Exploration
The structural characteristics of inner flow field in a pipeline are the key factors influencing the self-propelling capacity and descaling-unblocking capability of the self-propelled drill bit. To address the problem concerning the effect of the changes in the inner flow field of a pipeline under the joint action of multiple jets on the self-propelling force and the resistance to water backflow, the changes of inner flow field in the pipeline under different conditions were numerically analyzed based on FLUENT, and thus the influence law of the angle of rear nozzle, the rotational speed, the annular ratio and the system pressure …
One Surface Borehole With Multi-Usage Gas Drainage Key Technology For Abandoned Well And Its Application, Fu Junhui
Coal Geology & Exploration
Gas drainage from mining area could be realized through the reconstruction and reuse of abandoned surface gas wells in the coal mine area , which has multiple economic and environmental benefits such as ensuring the safe production of mining, the effective utilization of gas resources, and reducing the pressure of gas escape on the environment. In view of this purpose, the idea of “one surface borehole with multi-usage” gas drainage technology for abandoned wells was proposed based on the characteristics of the surface borehole and the abandoned wells in the mining area. By analyzing the conditions of the mining technology, …
Research On Permeability Model Of Coal Reservoir Along Producing Wellbores, Jia Lidan, Zhang Lin, Li Bobo, Wu Xuehai, Gao Zheng, Wang Zhonghui, Fu Jiale
Research On Permeability Model Of Coal Reservoir Along Producing Wellbores, Jia Lidan, Zhang Lin, Li Bobo, Wu Xuehai, Gao Zheng, Wang Zhonghui, Fu Jiale
Coal Geology & Exploration
Permeability is an important parameter to characterize gas flow. In order to ensure the safe and efficient gas drainage, it is necessary to explore the evolution characteristics of coal reservoir gas seepage at different positions from the producing wellbores. However, the effective stress, the gas adsorption/desorption capacity of coal matrix and the temperature of coal reservoir are constantly changing with the gas drainage, and even the drainage damage may occur, which makes the gas migration behavior in coal seam extremely complicated. In order to explore the seepage characteristics of coal reservoir gas during gas drainage, the space-time evolution function of …
Research Progress And Development Trend Of Staged Hydraulic Fracturing Technology In Long-Borehole Underground Coal Mine, Sun Siqing, Li Wenbo, Zhang Jian, Chen Dongdong, Zhao Jizhan, Zheng Kaige, Long Weicheng, Wang Chenyang, Jia Bingyi, Du Tianlin, Liu Le, Yang Huan, Dai Nan
Research Progress And Development Trend Of Staged Hydraulic Fracturing Technology In Long-Borehole Underground Coal Mine, Sun Siqing, Li Wenbo, Zhang Jian, Chen Dongdong, Zhao Jizhan, Zheng Kaige, Long Weicheng, Wang Chenyang, Jia Bingyi, Du Tianlin, Liu Le, Yang Huan, Dai Nan
Coal Geology & Exploration
Since the “13th Five-Year Plan”, significant progress has been made in the directional long-borehole staged hydraulic fracturing technology, equipment development and engineering demonstration application of underground coal mine through the technical research, equipment development and engineering test with directional long-borehole and staged hydraulic fracturing technology in combination, focusing on the two major issues of regional permeability enhancement, efficient gas drainage and rock weakening treatment of hard roof for coal seams in underground coal mine in China. It is mainly manifested in the following four aspects: (1) Two staged hydraulic fracturing technologies and tools with/without rig movement have been developed. Specifically, …
Enhanced Gas Drainage Technology By Staged Fracturing In Long Bedding Borehole In Hard Coal Bed Of Underground Coal Mine And Its Application, Wang Chenyang, Li Shugang, Zhang Yongtao, Guo Yi, Sun Siqing, Chen Dongdong, Dou Chengyi
Enhanced Gas Drainage Technology By Staged Fracturing In Long Bedding Borehole In Hard Coal Bed Of Underground Coal Mine And Its Application, Wang Chenyang, Li Shugang, Zhang Yongtao, Guo Yi, Sun Siqing, Chen Dongdong, Dou Chengyi
Coal Geology & Exploration
In view of the problems of rapid attenuation, long period and low efficiency of gas drainage in hard coal bed, the enhanced gas drainage technology of increasing the permeability of coal bed by staged fracturing in long bedding borehole was put forward for the medium-to-hard coal bed. Herein, research was conducted on No.4 coal bed of Shaanxi Binchang Mining Area. Specifically, the change characteristics of micro-pore structure of coal body before and after hydraulic fracturing were comparatively analyzed by high-resolution electron microscope (SEM) in the laboratory. Meanwhile, the stress characteristics of packer and the stability of borehole were simulated with …
Gas Drainage Borehole Completion Technology Of Directional Long Hole Drilling With Negative Angle, Ma Zan, Chen Dongdong, Xie Hengxing, Chen Tianzhu, Wang Bin, Jia Bingyi
Gas Drainage Borehole Completion Technology Of Directional Long Hole Drilling With Negative Angle, Ma Zan, Chen Dongdong, Xie Hengxing, Chen Tianzhu, Wang Bin, Jia Bingyi
Coal Geology & Exploration
Pre-drainage of coal seam gas with directional long boreholes is an effective technical means to achieve advanced control of coal mine gas area. Affected by mining deployment, negative-angle boreholes(downward holes) are widely used in production. Medium-hard coal seams have good porosity and usually do not require hole protection. However, the existing conventional methods can not effectively solve the problem of water accumulation in negative angle long boreholes. This paper takes the downward long boreholes in the No. 9 medium-hard coal seam of Longfeng Coal Mine in Guizhou as the research object. Two sets of directional long boreholes are constructed in …
The Concealed Small Faults Detection Based On Gas Drainage Boreholes Along And Cross The Coal Seam, Xue Honglai, Wen Zhe
The Concealed Small Faults Detection Based On Gas Drainage Boreholes Along And Cross The Coal Seam, Xue Honglai, Wen Zhe
Coal Geology & Exploration
The faults have great influence on coal and gas outburst disasters, and accurate detection of faults location is very important to prevent such disasters. At present, large number of gas drainage boreholes were drilled in coal mines, but the geological information contained in these boreholes is not fully paid attention to, thus the method to detect concealed faults by gas-drainage boreholes was proposed. In this paper, by establishing a mathematical model for fault detection based on gas drainage drilling, a three-dimensional coordinate of fault planes and coal seam floors is calculated, and basic parameters such as fault location, drop, attitude …
Quantitative Study Of 3d Numerical Simulation On Optimizing Borehole Layout Spacing Of Gas Drainage, Chen Yuexia, Chu Tingxiang, Chen Peng, Tang Yang
Quantitative Study Of 3d Numerical Simulation On Optimizing Borehole Layout Spacing Of Gas Drainage, Chen Yuexia, Chu Tingxiang, Chen Peng, Tang Yang
Coal Geology & Exploration
In order to optimize the spacing of boreholes and realize efficient drainage, based on the fluid solid coupling model, a three-dimensional geometric model was established to make it closer to the field reality, the gas drainage processes of a coal mine with different borehole spacing were simulated using COMSOL software. The results show that: the effective drainage area was visualized by the three-dimensional diagram of the isobaric surface with gas pressure of 0.74 MPa, and the influence of borehole spacing on the extraction efficiency was discussed. The results show that: the effective extraction radius is about 1.5 m during gas …
Numerical Simulation And Test Of Gas Drainage With Water Jet Layered Pressure Relief And Permeability Enhancement In Soft Coal Seam, Liu Xiao, Li Yong, Xuan Dequan, Hu Shixiong, Jing Tianxiang, Xu Sen
Numerical Simulation And Test Of Gas Drainage With Water Jet Layered Pressure Relief And Permeability Enhancement In Soft Coal Seam, Liu Xiao, Li Yong, Xuan Dequan, Hu Shixiong, Jing Tianxiang, Xu Sen
Coal Geology & Exploration
Hydraulic punching is the main technical measure to enhance permeability and drainage of coal seam gas. The pressure relief effect is mainly evaluated by the coal output. However, there are some problems such as large coal output, uneven pressure relief and easy stress concentration. Therefore, this paper puts forward the soft coal interlayer water jet layered pressure relief and permeability increasing gas drainage technology. Considering the influence of gas pressure compression and coal matrix adsorption gas expansion on the coal mass deformation, a multiphysics theoretical model under the coupling condition of stress field, fracture field and seepage field was established. …
Application Of Controllable Electric Pulse Wave Permeability-Enhancing Technology In The Low-Permeability Coal Seams, An Shigang, Chen Dianfu, Zhang Yongmin, Kong Delei, Li Yang, Zhang Di, Wang Yang
Application Of Controllable Electric Pulse Wave Permeability-Enhancing Technology In The Low-Permeability Coal Seams, An Shigang, Chen Dianfu, Zhang Yongmin, Kong Delei, Li Yang, Zhang Di, Wang Yang
Coal Geology & Exploration
Controllable electric pulse wave permeability-enhancing technology is one of the ideal measures for anti-reflection transformation of low-permeability coal seams. The optimization of construction schemes needs to be solved urgently. Aiming at this problem, in the low-permeability coal seam of Baode coal mine, controllable electric pulse wave permeability-enhancing technology was adopted to optimize the permeability-enhancing construction scheme of the boreholes. Test results show that the controllable electric pulse wave permeability-enhancing effect is the best under the condition of the average permeability-enhancing section of 131 m, the impact density of 0.5 times/m and the average daily extraction volume in an anti-reflection borehole …
Foam Drilling Technology And Application For Broken Soft Coal Seam In Underground Coal Mine, Ji Qianhui, Dong Mengmeng, Liu Jianlin, Shi Lei
Foam Drilling Technology And Application For Broken Soft Coal Seam In Underground Coal Mine, Ji Qianhui, Dong Mengmeng, Liu Jianlin, Shi Lei
Coal Geology & Exploration
Aiming at the limitation of middle pressure air drilling for gas drainage in soft and broken coal seam, such as limited drill cutting removal capacity, and dust pollution, foam drilling technique research in underground coal mines was carried out. CFD simulation of the flow field during the drilling process was conducted to obtain the optimized drilling tool structure parameters for efficient drill cutting transportation. Optimal structural parameters of wide-blade milled auger drill rod with the number of heads 3, the groove width 26 mm, and the pitch 110 mm were determined. A foam perfusion system suitable for underground coal mining …
Directional Drilling Technology And Equipment Of Pneumatic Screw Motor In Soft Seam, Zhang Jie, Wang Yi, Huang Hanjing
Directional Drilling Technology And Equipment Of Pneumatic Screw Motor In Soft Seam, Zhang Jie, Wang Yi, Huang Hanjing
Coal Geology & Exploration
Aiming at the drilling problems of shallow depth, uncontrollable trajectory and blind area of extraction in soft coal seam, the directional drilling technology of pneumatic screw motor was invented, and the directional drilling equipment consisting of pneumatic screw motor, narrow structure directional drilling rig and MWD system were formed. The air directional drilling technology and hole-completion technology were studied and developed. The technology of drilling and hole-completion solves the problem of long-distance safe drilling and hole protection of directional drilling along soft coal seam. The technology has been successfully tested in a coal mine, Huainan, with 30 test boreholes with …
Analysis Of Suitable Development Technology Of Cbm(Gas) In Guizhou, Xu Xiaoqian, Meng Yingfang, Duan Zhengpeng, Li Guohong, Li Qingsong
Analysis Of Suitable Development Technology Of Cbm(Gas) In Guizhou, Xu Xiaoqian, Meng Yingfang, Duan Zhengpeng, Li Guohong, Li Qingsong
Coal Geology & Exploration
In recent years, technical bottlenecks have been encountered in the practice of CBM exploration and development in Guizhou Province, selecting suitable development technology is one of the key issues. Based on the background that CBM exists in thin coal seams and geological structures are complicated in Guizhou, combined with successful development and utilization of CBM, the CBM development and utilization technology suitable for complex geological conditions in Guizhou was put forward. Air drilling is recommended for drilling in Guizhou, according to different distance of thin seams, such as optical casing composite fracturing and salvageable bridge plug fracturing can be used. …