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Full-Text Articles in Engineering
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 …
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 …
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, …
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 …
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 …
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. …