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2020

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Articles 151 - 180 of 294

Full-Text Articles in Oil, Gas, and Energy

Analysis Of Paleoclimatic Cycles In The Ultra Thick Coal Seam Of Yan'an Formation In The Southern Ordos Basin, Dong Guoqi, Wang Dongdong, Liu Haiyan, Mao Qiang, Yin Lusheng Jun 2020

Analysis Of Paleoclimatic Cycles In The Ultra Thick Coal Seam Of Yan'an Formation In The Southern Ordos Basin, Dong Guoqi, Wang Dongdong, Liu Haiyan, Mao Qiang, Yin Lusheng

Coal Geology & Exploration

Coal is a climate-sensitive sediment that contains abundant paleoclimate information. In order to find out the paleoclimate information contained in the coal seam and the evolution of its controlling factors, the No.4 thick coal seam in the first member of Yan’an Formation in the south of Ordos basin was studied. Based on the intensive sampling of the thick coal seam, the information of organic macerals, major and trace elements, and stable carbon isotopes of organic matter were systematically tested. By using the macerals, characteristic elements and carbon isotopes of coal and rocks, four cycles of paleoclimate with alternation of warm-wet …

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Change Law Of Adsorption/Desorption Energy Of Coal With Different Water Content Under The Action Of Far Infrared, Ma Kai, Ma Qianqian, Shi Yongtao Jun 2020

Change Law Of Adsorption/Desorption Energy Of Coal With Different Water Content Under The Action Of Far Infrared, Ma Kai, Ma Qianqian, Shi Yongtao

Coal Geology & Exploration

The essence of coal gas adsorption/desorption process is the process of interaction between gas molecules and molecules or atoms on the surface of the coal matrix, and the nature of the interaction is energy change. In order to deeply study the coalbed gas adsorption/desorption rules and energy change rules under the action of far infrared, the self-developed device was used to perform CO2 adsorption/desorption experiments on coal samples with different water contents under the action of far infrared. Then, the experimental results are calculated using the adsorption/desorption energy change model obtained from the principle of far-infrared thermal radiation, and …

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Practice And Understanding Of Multi-Layer Drainage Of Cbm Wells In Liupanshui Area, Liu Jiang, Sang Shuxun, Zhou Xiaozhi, Bi Caiqin, Jin Jun, Shan Yansheng Jun 2020

Practice And Understanding Of Multi-Layer Drainage Of Cbm Wells In Liupanshui Area, Liu Jiang, Sang Shuxun, Zhou Xiaozhi, Bi Caiqin, Jin Jun, Shan Yansheng

Coal Geology & Exploration

To improve the effect of drainage and extraction of coalbed methane wells, it is necessary to divide the drainage and production stages reasonably and formulate corresponding control measures. Based on the previous exploration and trial production of coalbed methane in Liupanshui area, this paper analyzed the geological characteristics of coalbed methane and the development characteristics of coal reservoirs in the area, and studied the drainage effect of the combined layers of two wells comparatively. The research shows that the area has several basic characteristics, including many coal seams, thin single-layer thickness, high gas content, high reservoir pressure, low coal seam …

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Acoustic Emission Characteristics And Damage Evolution Of Coal-Rock Under Different Confining Pressures, Yu Jie, Liu Xiaohui, Hao Qijun Jun 2020

Acoustic Emission Characteristics And Damage Evolution Of Coal-Rock Under Different Confining Pressures, Yu Jie, Liu Xiaohui, Hao Qijun

Coal Geology & Exploration

Using PCI-2 acoustic emission(AE) system, the AE experiments of different confining pressures (0, 8, 16, 5 MPa) were carried out in Baijiao coal mine in Furong, Sichuan Province, in order to reveal the change rule of ringing count rate, the temporal and spatial distribution of AE, b value of AE and damage characteristics of damaged coal-rock under different confining pressures, and to provide a theoretical basis for prediction of coal-rock damage. The results show that the AE phenomenon can reflect the crack propagation of coal-rock and the confining pressure can restrain the damage of coal-rock. With the increase of confining …

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Test Of Mechanical Properties Of Limestone Under Hydraulic Pressure-Stress Coupling, Tian Shukun Jun 2020

Test Of Mechanical Properties Of Limestone Under Hydraulic Pressure-Stress Coupling, Tian Shukun

Coal Geology & Exploration

To study the mechanical properties of limestone with water-rich saturated circumstance under water pressure-stress coupling, compression failure tests of limestone samples with different water pressure were carried out by using a self-developed permeability test device, the device can realize uniaxial compression test. Then, the stress-strain characteristics of limestone, the effect of hydraulic pressure on uniaxial compressive strength, the elastic modulus and the deformation modulus, and the correlation between breaking characteristics and hydraulic pressure were tested. The results show that the increased hydraulic pressure has a significant influence on the stress-strain curve and strength characteristics. With the increase of hydraulic strength, …

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Influence Factors And Formation Properties Of Temperature Field In The Frozen Wall Of Double Ring Pipes, Li Huaixin, Lin Bin, Wang Peng Jun 2020

Influence Factors And Formation Properties Of Temperature Field In The Frozen Wall Of Double Ring Pipes, Li Huaixin, Lin Bin, Wang Peng

Coal Geology & Exploration

In order to research the change law of the temperature field of the frozen wall of double-circle pipes, an auxiliary shaft in Huainan coalmine was taken as the research object, the FLAC3D software was used to numerically simulate the formation process of the temperature field of the frozen wall of double-circle pipes and the influence of different factors on average temperature of frozen wall based on the relevant geological parameters. The research results show that temperature of the soil in the double-circle pipes is the lowest, and temperature on both sides increases gradually, the interval between frozen holes is …

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Model-Driven Energy Attenuation Method For Coal Seam Strong Reflection, Zhang Xianxu Jun 2020

Model-Driven Energy Attenuation Method For Coal Seam Strong Reflection, Zhang Xianxu

Coal Geology & Exploration

The reflection of coal seam in seismic data has the characteristics of strong energy, which makes the reflection of adjacent strata often concealed by the reflection of coal seam. This makes it difficult to image the adjacent weak layer and lithological interpretation difficult. Aiming at this problem, a model-driven energy attenuation method for coal seam strong reflection was proposed. This method uses the coal thickness calculated by logging and measured by borehole in underground coal mine to construct cross plot with reflection amplitude of coal seam, and fit the relationship formula between amplitude and thickness. The digital model was constructed …

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Seismic Impedance Inversion Of Coal Field With Reflectivity Method Based On Bayesian Theory, Yang Zhen, Gao Zhenyu, Liu Xingye Jun 2020

Seismic Impedance Inversion Of Coal Field With Reflectivity Method Based On Bayesian Theory, Yang Zhen, Gao Zhenyu, Liu Xingye

Coal Geology & Exploration

Seismic inversion can reflect the morphology of subsurface formation and facies information more intuitively. Seismic impedance inversion can directly produce elastic information of underground media, providing reliable information for subsequent coal identification, water channel prediction and collapse column distinguishing. A Bayesian-based inversion of reflectivity method was developed. It can consider the various propagation effects of seismic waves and solve the objective function nonlinearly, which can more accurately calculate the impedance and improve the inversion resolution. The method is applied to the actual data from Buertai coal mine and satisfactory results are output, which effectively verifies the feasibility and effectiveness of …

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Design And Numerical Simulation Of Multi-Layer Bit With Extra-High Matrix, Sun Qibin, Shen Lina, Yang Gansheng, Tian Guoliang, Ruan Hailong, Chen Xi Jun 2020

Design And Numerical Simulation Of Multi-Layer Bit With Extra-High Matrix, Sun Qibin, Shen Lina, Yang Gansheng, Tian Guoliang, Ruan Hailong, Chen Xi

Coal Geology & Exploration

Aiming at the problem that the life of the diamond bit is limited by the height of the bit matrix, an optimized design scheme of an impregnated diamond bit with extra-high multi-layer matrix was proposed. In the design of the bit, eccentric staggered cutting teeth, alternate waterways and water baffles were introduced to ensure the cooling and effective drilling of the bit. Through strength and hydraulic flow field simulation, the strength of the drill bit was checked, the rationality of the waterway structure was verified, and the finished product of the drill bit was further realized. The drill bit breaks …

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Influence Of Water Injection In Burst-Prone Coal Seam On Suction And Sticking During Drilling, Hao Zhiyong, Li Zhiwei, Pan Yishan Jun 2020

Influence Of Water Injection In Burst-Prone Coal Seam On Suction And Sticking During Drilling, Hao Zhiyong, Li Zhiwei, Pan Yishan

Coal Geology & Exploration

When the spiral drill pipe is used to predict and evaluate the dynamic disasters such as rock burst, the drilling dynamic phenomena such as suction and sticking are easy to occur. In order to study the influence of water injection in burst-prone coal seam on suction and sticking, the mechanism of dynamic phenomenon of suction and sticking was analyzed by establishing the mechanical model of drill pipe, pointing out that the stress of coal body and the amount of drilling cuttings are the important factors that affect the occurrence of suction and sticking, deriving the calculation formula of drilling mechanical …

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Table Of Contents, The Editors Jun 2020

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

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The Structural Characteristics And Their Influence On Production Of Buliangou Coal Mine, Ma Liang, Guo Rui Jun 2020

The Structural Characteristics And Their Influence On Production Of Buliangou Coal Mine, Ma Liang, Guo Rui

Coal Geology & Exploration

Jungar coalfield is located at the turning point of Yimeng uplift and Jinxi flexure belt in Ordos basin. There are many kinds of mine structures in the coalfield, and the structural complexity has changed greatly before and after the exposure by mine production. Taking the fold, fault, karst collapse column, igneous rock intrusion and other geological structures exposed by geological exploration and mining as the research object, quantitative or semi-quantitative evaluation of structural development characteristics in the mine was carried out by means of mathematical statistics, and the formation mechanism, evolution background of different geological structures were analyzed. The main …

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Experiment Of Mesostructure And Hydrologic Characteristics Of Weakly Cemented Soft Rocks In Western China, Zhang Jiafan, Cheng Shufan, Wang Huan, Gao Zhuang, Zhou Feiwen, Zhou Hongwen Jun 2020

Experiment Of Mesostructure And Hydrologic Characteristics Of Weakly Cemented Soft Rocks In Western China, Zhang Jiafan, Cheng Shufan, Wang Huan, Gao Zhuang, Zhou Feiwen, Zhou Hongwen

Coal Geology & Exploration

In order to accurately grasp the hydrologic characteristics of weakly cemented soft rocks in western China, the hydraulic and mechanical properties of red sandstone collected from northern Shaanxi mining area were tested. Based on the scanning image of scanning electron microscope(SEM), the mesostructural characteristics of the rocks were analyzed, and the relationship between the mesostructure of rocks and its macroscopic hydrologic characteristics was established. The results show that red sandstone has obvious characteristics of water saturation and water absorption and expansion, and its softening coefficient is 0.64. Under the action of pressure water erosion and dry and wet cycle, the …

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Fractal Theory-Based Seepage Model Of Hershel-Bulkley Fluid In Porous Medium, Yang Xian, Lu Wei, Jin Xin, Chen Juan, Feng Xingfa Jun 2020

Fractal Theory-Based Seepage Model Of Hershel-Bulkley Fluid In Porous Medium, Yang Xian, Lu Wei, Jin Xin, Chen Juan, Feng Xingfa

Coal Geology & Exploration

Slurry is a kind of widely-used engineering fluid. Slurry will seeps into the formation in the process of construction, which has a certain impact on the project. In order to make deeper study on the seepage mechanism of slurry, the formation is simulated as porous medium, the slurry is simulated as Hershel-Bulkley fluid which can more comprehensively reflect its rheological properties, and the seepage model of Hershel-Bulkley fluid in porous medium was established based on Fractal theory. Based on the calculation results of seepage model, the effect of pressure gradient, flow index, consistency coefficient and porosity on the instantaneous average …

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Influence Of Parting In Composite Coal Seam On Interpretation Of Fault Throw By Channel Wave Seismic Exploration, Su Xiaoyun Jun 2020

Influence Of Parting In Composite Coal Seam On Interpretation Of Fault Throw By Channel Wave Seismic Exploration, Su Xiaoyun

Coal Geology & Exploration

The channel wave seismic exploration technology has achieved relatively reliable result in detection of faults, collapse columns and the change of coal thickness in working faces, now becomes the preferred method for detection of underground geological structures. But for detection of geological structures in partings of composite coal seams the method has still certain problems. In order to study the influence of partings in composite coal seams on detection of channel wave seismic exploration, various models were built by changing thickness, lithology of parting in composite coal seams and experimenting with channel wave seismic detection in Shanxi to study how …

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Suppression Of Multiple Reflected Refraction In Shallow Low-Velocity Zones By Vertical Combination Of Seismic Sources, Fu Yanning, Chang Suoliang, Zhang Sheng, Liu Zuiliang, Yang Yong, Chen Qiang, Liu Bo, Xu Yuying Jun 2020

Suppression Of Multiple Reflected Refraction In Shallow Low-Velocity Zones By Vertical Combination Of Seismic Sources, Fu Yanning, Chang Suoliang, Zhang Sheng, Liu Zuiliang, Yang Yong, Chen Qiang, Liu Bo, Xu Yuying

Coal Geology & Exploration

A special type of multiple reflected refraction often appears in seismic records in areas with low-velocity structures. It seriously affects the closed reflection wave, which causes the distortion of the reflection wave shape and affects the correct interpretation of the seismic data. Based on the forward simulation of the multiple reflected refraction equation, the generation mechanism of multiple reflected refraction in the shallow low-velocity zones was set forth. A method of suppressing multiple reflected refraction by vertically combined dual sources was proposed. The formation parameters(formation thickness and velocity)are obtained according to the methods of small refraction and micro logging in …

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Exploration And Quantitative Evaluation Of Overburden Strata “Three Zones” In Deep Strip Mining, Liu Zhen, Wang Yutao, Liu Xiaoping, Wang Xiaodong Jun 2020

Exploration And Quantitative Evaluation Of Overburden Strata “Three Zones” In Deep Strip Mining, Liu Zhen, Wang Yutao, Liu Xiaoping, Wang Xiaodong

Coal Geology & Exploration

In order to study the height of overburden fractures in deep strip mining, engineering geological drilling, borehole television and coalfield well logging have been applied to detect and analyze the overburden fractures in a coal mine in Jining coalfield. The results indicate that, under the strip mining with gentle dip(6°), deep depth(538 m) and 1:2 mining-retention ratio(mining -50 m and remaining -100 m), the “three zones” develop prominently, presenting “wavy” destruction in space, and the goaf has no obvious cavity. The height of caving zone is 8.45 m which is 3.0 times of the mining height, and the fault zone …

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Stacking Angle Of Slurry-Aeolian Sand Dual-Phase Medium Filling Material, Bai Zhongrong Jun 2020

Stacking Angle Of Slurry-Aeolian Sand Dual-Phase Medium Filling Material, Bai Zhongrong

Coal Geology & Exploration

Stacking angle is an important parameter to describe the spatial accumulation pattern of filling material in the goaf. It has important guiding significance for determining the drilling distance, optimizing the slurry configuration and adjusting the grouting process parameters. In order to grasp the variation law of stacking angle of slurry-aeolian sand dual-phase medium filling material, using self-flow stacking model experiment of tailings and rheological properties experiment, the mixing ratio of aeolian sand was taken as a variable to determine the slurry accumulation parameters and rheological parameters on different conditions of sand ratio. Based on this, Sofra & Boger formula was …

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Regional Distribution And Geotectonic Control Of Late Permian Tectonically Deformed Coal In Zhina Coalfield, Zhou Peiming, Gao Wei, Deng Lan, Fu Wei Jun 2020

Regional Distribution And Geotectonic Control Of Late Permian Tectonically Deformed Coal In Zhina Coalfield, Zhou Peiming, Gao Wei, Deng Lan, Fu Wei

Coal Geology & Exploration

In order to find out the tectonically deformed coal distribution law of Zhina coalfield, by sorting out and analyzing the data of more than 200 coal-bearing structural units including Bide syncline, Santang syncline, Zhuzang syncline, Arcong syncline and Guanzhai syncline in Zhina coalfield, Guizhou Province, combined with logging curve analysis, the regional distribution characteristics of coal body structure and structural control factors of No.6, No.16 and No.27 main coal seams are comprehensively analyzed. The study shows that from the west to the east, the proportion of tectonically deformed coal in Zhina coalfield increases gradually. The coal in the western part …

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Physical Simutation Experiment Investigation On Hydraulic Fracture Propagation In High-Dip Coal Seam, Jiang Wei, Zhang Jun, Zhong Jie, Zhao Chen, Tang Zhuyun, Lu Haibing, Yi Xinbin, Wang Hai Jun 2020

Physical Simutation Experiment Investigation On Hydraulic Fracture Propagation In High-Dip Coal Seam, Jiang Wei, Zhang Jun, Zhong Jie, Zhao Chen, Tang Zhuyun, Lu Haibing, Yi Xinbin, Wang Hai

Coal Geology & Exploration

In order to study the hydraulic fracture geometry in high-dip coal seam, a large-scale true triaxial fracturing simulation system was used to carry out physical simulation experiments, and the hydraulic fracture geometry of the maximum horizontal principal stress along the strike direction and along the dip direction-in 60° dip coal seam were investigated respectively. Experimental results of the maximum principal stress direction along the strike direction show that: hydraulic fracture initiation is easily; fracture height is limited in the whole time; fracture connectivity is good; fracture propagates mainly along bedding and natural fracture, vertical fracture is formed; the influence of …

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Production Decline Law And Influencing Factors Of High-Rank Coal Cbm Wells, Jia Huimin, Hu Qiujia, Mao Jianwei,, Mao Chonghao, Liu Chunchun, Zhang Qing, Liu Changping Jun 2020

Production Decline Law And Influencing Factors Of High-Rank Coal Cbm Wells, Jia Huimin, Hu Qiujia, Mao Jianwei,, Mao Chonghao, Liu Chunchun, Zhang Qing, Liu Changping

Coal Geology & Exploration

In order to reveal the production decline law of high-rank coal CBM wells, based on the development data of Fanzhuang block in southern Qinshui basin for more than 10 years, this paper studies the decline point, decline type and influencing factors of high-rank coal CBM wells by means of numerical simulation and statistical analysis. The results show that the decline point of the Fanzhuang block is 25% and the average decline point of the single well is 21%. Most wells begin to decline after drainage of 4 years. The decline point of CBM well is determined by matrix permeability and …

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Fracturing Parameters Analysis And Productivity Evaluation Of Vertical Coalbed Methane Wells With Nitrogen Foam, Li Hengle, Cao Yunxing, Zhou Dan, Chai Xuezhou, Liu Tongji, Feng Peiwen, Shi Bin, Tian Lin Jun 2020

Fracturing Parameters Analysis And Productivity Evaluation Of Vertical Coalbed Methane Wells With Nitrogen Foam, Li Hengle, Cao Yunxing, Zhou Dan, Chai Xuezhou, Liu Tongji, Feng Peiwen, Shi Bin, Tian Lin

Coal Geology & Exploration

Fracturing parameters are important parameters that affect the fracturing effect, fracture characteristics and CBM productivity. Through an in-depth understanding of the influence of fracturing parameters on productivity, it is essential to optimize the fracturing process and increase the productivity of CBM wells. Taking 45 nitrogen foam fracturing wells in Lu’an mining area as the research object, the types of fracturing operation curves and their effects on productivity were studied. The relationship between fracturing fluid dosage and productivity was discussed. The differences in productivity of nitrogen foam wells and hydraulic fracturing wells was compared and analyzed. The results show that: Nitrogen …

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Hydrogeochemical Evolution Of No.15 Coal Seam And Limestone K2 In Southern Qinshui Basin, Li Zhongcheng, Wu Jianguang, Wang Jianzhong, Wu Xiang, Lu Guojun Jun 2020

Hydrogeochemical Evolution Of No.15 Coal Seam And Limestone K2 In Southern Qinshui Basin, Li Zhongcheng, Wu Jianguang, Wang Jianzhong, Wu Xiang, Lu Guojun

Coal Geology & Exploration

Based on the water test data of No.15 coal roof K2 limestone and No.15 coalbed methane well in the southern Qinshui basin, the characteristics, types and the genetic mechanism of water chemical composition were systematically studied by statistical and comparative methods. The evolution model was built to systematically describe the various reactions and effects of limestone and coalbed water in the recharge zone, runoff zone and detention zone. The results show that the K2 limestone water and the No.15 coal seam water will undergo ion exchange, mixing and CO2 action. The K2 limestone water is mainly …

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Surface Efficient Gas Extraction Mode Based On Full Coverage Of Working Face, Fang Jiawei, Han Baoshan, Zhou Jiajia, Wang Zhengxi, Zhang Dingliang, Liu Jia, Xu Jianjun Jun 2020

Surface Efficient Gas Extraction Mode Based On Full Coverage Of Working Face, Fang Jiawei, Han Baoshan, Zhou Jiajia, Wang Zhengxi, Zhang Dingliang, Liu Jia, Xu Jianjun

Coal Geology & Exploration

Aiming at the problems of soft and broken coal seam, low permeability, difficulty in gas extraction and low drainage efficiency in working face, a full-coverage mode for gas extraction in working face through the horizontal well group with staged fracturing roof at both ends is proposed. Taking a mine in Suxian mining area of Huaibei coalfield as an example, based on the characteristics of in-situ stress and working face distribution, combined with the analysis of gas geological conditions and coal seam mechanical properties in the area, the cross section dipole sonic logging method was used to optimize the orientation of …

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Effect Of Acidification On The Microstructure And Physical Properties Of Shale, Chen Liuyu, Li Xijian, Shen Zhonghui, Xu Shiqing, Ma Shengxiang, Yin Xin Jun 2020

Effect Of Acidification On The Microstructure And Physical Properties Of Shale, Chen Liuyu, Li Xijian, Shen Zhonghui, Xu Shiqing, Ma Shengxiang, Yin Xin

Coal Geology & Exploration

As the main shale gas reservoir in Guizhou, it is proved that Longmaxi Formation has good shale gas accumulation conditions and resource development potential. In order to reveal the response law of acidification on the micropore structure and physical properties of Longmaxi Formation shale in Guizhou, the difference in physical properties of shale microstructures before and after acidification, such as pore volume, porosity, specific surface area and pore size distribution was quantitatively characterized by X-ray diffraction(XRD) analysis, mercury intrusion measurement, low-temperature nitrogen adsorption and nuclear magnetic resonance(NMR) experiment. The structural characteristics of the shale pores before and after acidification were …

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Application Of Time Series Model In Water Inflow Prediction Of Working Face, Shi Longqin, Wang Yaru, Qiu Mei, Gao Weifu Jun 2020

Application Of Time Series Model In Water Inflow Prediction Of Working Face, Shi Longqin, Wang Yaru, Qiu Mei, Gao Weifu

Coal Geology & Exploration

In practical production of mines, the prediction of mine water inflow is of great significance for mine water prevention and control. Taking working face 1301 of Yuncheng coal mine as the research object, and without considering the influence of seasonal factors, ARIMA-the time series analysis model-is used to establish the functional relationship between mine water inflow and time, which proves that the time series of water inflow in working face 1301 of Yuncheng coal mine is affected by seasonal factors. Then, based on the principle of addition and decomposition of time series, the long-term trend, seasonal indexes, circulating factors and …

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Development Characteristics Of Water Conducted Fracture Zone Based On Overburden Structural Effect, Cao Zubao, Wang Qingtao Jun 2020

Development Characteristics Of Water Conducted Fracture Zone Based On Overburden Structural Effect, Cao Zubao, Wang Qingtao

Coal Geology & Exploration

In order to study the roof water disaster caused by coal mining in Huanglong coalfield, taking mining failure of layered overburden as research object, four typical composite structural models for coal-soft rock-hard rock-soft rock-hard rock(combination I), coal-soft rock-soft rock-hard rock-hard rock(combination Ⅱ), coal-hard rock-soft rock-hard rock-soft rock(combination Ⅲ) and coal-hard rock-hard rock-soft rock-soft rock(combination IV) were generalized. Numerical simulation and theoretical calculation were used to analyze the mining failure characteristics of different overburden combinations and correlation between water conducting fissures and lithologic combination structure of overburden. The law of the effect of overburden structure on the development height of water …

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The Law Of Soaking Infiltration And Collapse Deformation In Typical Loess-Paleosol Series, Zhao Jingang, Lyu Yuanqiang, Chao Jun, Yang Zhe, Xia Meng Jun 2020

The Law Of Soaking Infiltration And Collapse Deformation In Typical Loess-Paleosol Series, Zhao Jingang, Lyu Yuanqiang, Chao Jun, Yang Zhe, Xia Meng

Coal Geology & Exploration

In order to investigate the law of moisture migration and collapse deformation of the typical loess-paleosol series, on the basis of water immersion test of the large test pits of Xi’an North-airport intercity rail transit in the loess tableland of Weibei, the real-time in-site observation was adopted, the soaking infiltration and collapse deformation of collapsible soil layer under conditions of non water seepage hole were traced and tested. The results show that: The movement of water immersion is dominated by vertical movement in the early stage. The whole form is like a continuous increase of “weight” shape. As the water …

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Numerical Calculation Of Temperature Field Of Freeze-Sealing Pipe Roof Method In Gongbei Tunnel, Long Wei, Rong Chuanxin, Duan Yin, Guo Ke Jun 2020

Numerical Calculation Of Temperature Field Of Freeze-Sealing Pipe Roof Method In Gongbei Tunnel, Long Wei, Rong Chuanxin, Duan Yin, Guo Ke

Coal Geology & Exploration

This paper took the Gongbei tunnel in the Zhuhai Connection Section of the Hong Kong-Zhuhai-Macao Bridge as an example to study the development of the temperature field of the Freeze-Sealing Pipe Roof Method. Based on the heat transfer theory of two-dimensional porous media, the FEM software COMSOL was used to numerically analyze the actual working conditions of the active freezing period, the numerical calculation was verified by field measurement. The development and distribution of the temperature field before and after the opening of the special-shaped freezing pipes was studied. The results showed that: when freezing for 30 days, the concrete …

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Detection Technique And Application Of Transmission In-Seam Wave In Thin Coal Seam, Yang Hui Jun 2020

Detection Technique And Application Of Transmission In-Seam Wave In Thin Coal Seam, Yang Hui

Coal Geology & Exploration

Aiming at the problem of serious attenuation of channel wave in thin seam and its limited distance of propagation, a method of restricted CT imaging was proposed by using the furthest in-seam wave propagation distance. Firstly, the variation of in-seam wave frequency with different thickness of coal seam was studied by theoretical derivation. Taking a 1.5m thin seam as the main research object, the attenuation characteristics of channel wave were simulated by forward modeling, and the effective propagation distance of channel wave was determined. The actual data of No. 15 coal seam in a coal mine in Shandong Province shows …

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