Experiment Of Mesostructure And Hydrologic Characteristics Of Weakly Cemented Soft Rocks In Western China,
2020
Department of Mechanics, Xi'an University of Science and Technology, Xi'an 710054, China
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 …
Exploration And Quantitative Evaluation Of Overburden Strata “Three Zones” In Deep Strip Mining,
2020
Xi’an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi’an 710078, China
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 …
Production Decline Law And Influencing Factors Of High-Rank Coal Cbm Wells,
2020
PetroChina Huabei Oilfield Company, Changzhi 046000, China
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 …
Fracturing Parameters Analysis And Productivity Evaluation Of Vertical Coalbed Methane Wells With Nitrogen Foam,
2020
School of Resources and Environment, Henan University of Engineering, Zhengzhou 451191, China
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 …
Hydrogeochemical Evolution Of No.15 Coal Seam And Limestone K2 In Southern Qinshui Basin,
2020
China United Coalbed Methane Corporation Ltd., Beijing 100015, China
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 …
Effect Of Acidification On The Microstructure And Physical Properties Of Shale,
2020
Mining College, Guizhou University, Guiyang 550025, China; Engineering Center for Safe Mining Technology Under Complex Geologic Condition, Guiyang 550025, China; Institute of Gas Disaster Prevention and Coalbed Methane Development of Guizhou University, Guiyang 550025, China
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 …
Common Midpoint Gather Constraint-Based Impedance Inversion Of Ground Penetrating Radar,
2020
School of Geosciences and Info-Physics, Central South University, Changsha 410083, China; Key Laboratory of Metallogenic Prediction of Nonferrous Metal and Geological Environment Monitoring, Ministry of Education, Central South University, Changsha 410083, China
Common Midpoint Gather Constraint-Based Impedance Inversion Of Ground Penetrating Radar, Dai Qianwei, Ning Xiaobin, Zhang Bin
Coal Geology & Exploration
GPR impedance inversion is an effective method to obtain accurately the intrinsic parameters of the subsurface medium. This method relies on low frequency information provided by logging data, but it is rarely accompanied by drilling in practical applications. To solve the problem, the common midpoint velocity analysis is employed to provide more low frequency component information for impedance inversion of GPR to finely reconstruct the dielectric parameter of subsurface in the framework of velocity-constrained inversion technique. Firstly, a layer model is specifically set up as an example to verify the feasibility of the developed velocity- constrained inversion to regulate the …
Water Environment Comprehensive Forewarning For Waterlogged Area In Huainan Based On Weber-Fechner Law,
2020
Nanjing Institute of Environmental Sciences,Ministry of Ecology and Environment, Nanjing 210042, China
Water Environment Comprehensive Forewarning For Waterlogged Area In Huainan Based On Weber-Fechner Law, Pei Wenming, Zhang Hui, Ju Changhua, Yao Suping, Ren Yongle, Ma Mengxiao, Qiu Kuanbiao
Coal Geology & Exploration
In area with high groundwater level in the east of China, long-time underground coal mining results in a large subsidence water area on the surface. The risk of water environment pollution in subsidence waters is increasing gradually with the influence of human activities. According to Weber-Fisher law, this paper took Panji waterlogged area of Huainan as the research object, selected the water quality evaluation indexes closely related to the water environment of the waterlogged area, analyzed the water environmental conditions of the waterlogged area in different periods, and quantitatively reflected the time and the area of the water environment quality …
Performance Test And Proportioning Optimization Of Loess-Based Grouting Materials In Coal Mining Subsidence Area Of Northern Shaanxi,
2020
Xi’an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi’an 710077, China
Performance Test And Proportioning Optimization Of Loess-Based Grouting Materials In Coal Mining Subsidence Area Of Northern Shaanxi, Cao Xiaoyi, Wang Yutao, Liu Xiaoping, Cao Zubao, Wu Boqiang
Coal Geology & Exploration
Grouting is the main treatment method of mining subsidence area, and the grouting materials have great influence on the grouting effect and cost. Taking the grout mix composed of loess and cement used in northern Shaanxi as the research object, the viscosity, the gelation time, the stone rate and 28 d uniaxial unconfined compressive strength of loess grout were studied by single factor and orthogonal tests. The influencing factors and changing rule of each index were analyzed. Meanwhile, the GA-BPNN prediction model of loess-based grout was established, and the multi-objective global optimization was carried out through GA. The grout ratio …
Stacking Angle Of Slurry-Aeolian Sand Dual-Phase Medium Filling Material,
2020
Xi’an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi’an 710079, China
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 …
Regional Distribution And Geotectonic Control Of Late Permian Tectonically Deformed Coal In Zhina Coalfield,
2020
Guizhou Provincial Bureau of Coal Geology, Guiyang 550008, China
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 …
Physical Simutation Experiment Investigation On Hydraulic Fracture Propagation In High-Dip Coal Seam,
2020
Fracturing and Acidizing Technology Service Center, PetroChina Research Institute of Petroleum Exploration &Development, Langfang 065007, China
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 …
Surface Efficient Gas Extraction Mode Based On Full Coverage Of Working Face,
2020
China Coal Research Institute, Beijing 100013, China; Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
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 …
Practice And Understanding Of Multi-Layer Drainage Of Cbm Wells In Liupanshui Area,
2020
School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116, China
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 …
Application Of Time Series Model In Water Inflow Prediction Of Working Face,
2020
College of Geological Sciences & Engineering, Shandong University of Science and Technology, Qingdao 266590, China
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 …
Fractal Theory-Based Seepage Model Of Hershel-Bulkley Fluid In Porous Medium,
2020
School of Resource, Environment and Safety Engineering, Hunan University of Science and Technology, Xiangtan 411201, China
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 …
Test Of Mechanical Properties Of Limestone Under Hydraulic Pressure-Stress Coupling,
2020
China Railway Construction Engineering Bureau Group Co. Ltd., Tianjin 300300, China; School of Civil Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, China
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, …
Development Characteristics Of Water Conducted Fracture Zone Based On Overburden Structural Effect,
2020
China Coal Research Institute, Beijing 100013, China; Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
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 …
The Law Of Soaking Infiltration And Collapse Deformation In Typical Loess-Paleosol Series,
2020
China Coal Xi'an Design Engineering Co. Ltd., China National Coal Group Corp., Xi'an 710054, China
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 …
Numerical Calculation Of Temperature Field Of Freeze-Sealing Pipe Roof Method In Gongbei Tunnel,
2020
School of Civil Engineering and Architecture, Anhui University of Science and Technology, Huainan 232001, China
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 …
