Molecular Simulation Of The Influence Of Foam Fracturing Fluid Additives On Coalbed Methane Diffusion,
2019
State Key Lab of Oil and Gas Reservoir Geology and Exploitation Engineering, Southwest Petroleum University, Chengdu 610500, China
Molecular Simulation Of The Influence Of Foam Fracturing Fluid Additives On Coalbed Methane Diffusion, Yang Zhaozhong, Han Jinxuan, Zhang Jian, He Rui, Lu Yanjun, Li Xiaogang
Coal Geology & Exploration
Materials Studio(MS) software was used to establish a slit pore molecular model which considers the in-teractions among water-bearing coal, foam agent and foam stabilizer. Based on molecular diffusion theory, the diffusion ability of methane molecule respectively affected by four common foam agents and four foam stabilizers was calculated. Compared to original water-bearing coal, self-diffusion coefficient of coalbed methane(CBM) is reduced by 71.3%, 74.7%, 56.3%, 54.0% after adding foaming agents including sodium dodecyl sulfonate(SDS), sodium lauryl sulfate(SLS), sodium dodecyl benzene sulfonate(SDBS) and lycine respectively. Based on adding SDBS into water-bearing coal, the self-diffusion coefficient of CBM is further reduced by 63.2%, …
Analysis On The Type Of Reservoir Pressure Drop And Drainage Control Of Coalbed Methane Well In The Southern Block Of Shizhuang,
2019
School of Energy and Resources, China University of Geoscience, Beijing 100083, China; Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering, Beijing 100083, China; Shanxi key Laboratory of Resources, Environment and Disaster Monitoring, Jinzhong 030600, China
Analysis On The Type Of Reservoir Pressure Drop And Drainage Control Of Coalbed Methane Well In The Southern Block Of Shizhuang, Yi Yongxiang, Tang Shuheng, Zhang Songhang, Yan Xinlu, Wang Kaifeng, Dang Feng
Coal Geology & Exploration
In order to fully understand the reservoir pressure variation characteristics of coalbed methane wells in the southern block of Shizhuang and based on the analysis of reservoir geological parameters and the analysis of actual production data, the reservoir pressures of different types of production wells are analyzed. The specific analysis of the drainage control and reservoir sensitivity effects is also carried out based on the abnormal wells. The results showed that the reservoir lamination of coalbed methane wells in the southern block of Shizhuang can be divided into three types, namely type of rapid pressure drop, type of medium-term stability …
Experimental Study On Contact Angle And Pore Characteristics Of Unsaturated Loess,
2019
School of Civil Engineering, Chang'an University, Xi'an 710061, China
Experimental Study On Contact Angle And Pore Characteristics Of Unsaturated Loess, Jing Yanlin, Wang Hao, Tao Chunliang, Yang Lina, Liu Jianwei, Wen Xin
Coal Geology & Exploration
Contact angle and pore size are important factors affecting soil wettability, permeability and capillarity. In order to further understand the capillary characteristics and permeability of unsaturated loess, the contact angle test and mercury intrusion test of unsaturated loess were carried out. The relationship between pore size and contact angle was analyzed in details. Moreover, the variation of pore and contact angle with depth was discussed. It is found that the contact angle of loess in the dry state is higher than the contact angle of loess in the natural state; as the depth of the formation increases, the contact angle …
The Influence Of Grounding Grid On Electromagnetic Detection Of Goaf,
2019
State Key Laboratory of Reliability and Intelligence of Electrical Equipment, Hebei University of Technology, Tianjin 300130, China; Key Laboratory of Electromagnetic Field and Electrical Apparatus Reliability of Hebei Province, Hebei University of Technology, Tianjin 300130, China; Institute of Electrical Engineering, Chinese Academy of Science, Beijing 100190, China
The Influence Of Grounding Grid On Electromagnetic Detection Of Goaf, Xu Xing, Weng Ling, Li Shiqiang, Liu Guoqiang
Coal Geology & Exploration
The existence of underground goaf can easily cause tilting and settlement of power towers, which is a major hidden factor in the safe and stable operation of power grid. To detect the mine goaf under the power transmission corridor is of great significance. When there is a grounding grid in the detection area, the grounding grid will have certain influence on the measured value. In this paper, the detection of mine goaf in the presence of a grounding grid is presented. Based on the theoretical analysis, the mathematical model is built, and the simulation model is conducted. The influence of …
Study On Local Volume Breakage Of Diamond-Impregnated Bit,
2019
Key laboratory of Deep Geo-drilling Technology of Ministry of Land and Resources, China University of Geosciences(Beijing), Beijing 100083, China
Study On Local Volume Breakage Of Diamond-Impregnated Bit, Sun Jiwei, Shen Lina, Yang Gansheng, Ye Jichao
Coal Geology & Exploration
To solve the problem of high energy consumption and slow drilling speed of impregnated diamond drill in hard rock, the method of volume crushing to improve drilling efficiency was put forward. In order to study the crushed volume of impregnated diamond bit in hard rock, firstly, an test of single diamond pressed into rock was designed. According to the experimental data, the first partial broken volume when single diamond was pressed into rock was the volume breakage type of impregnated diamond bit. Then the mathematical model of optimal drilling pressure and speed in first partial broken volume was deduced. By …
Evaluation Technology For Key Monitoring Area Of Early Warning Of Water Inrush From The Floor Of Working Face In Coal Mine,
2019
Hebei State Key Laboratory of Mine Disaster Prevention, North China Institute of Science and Technology, Beijing 101601, China
Evaluation Technology For Key Monitoring Area Of Early Warning Of Water Inrush From The Floor Of Working Face In Coal Mine, Liu Demin, Yin Shangxian, Lian Huiqing
Coal Geology & Exploration
Accurately delineating the key monitoring areas for water inrush warning of the floor of working face in coal mine and realizing the spatial matching of the monitoring position of the early warning system and the location of potential water inrush points are one of the urgent problems to be solved in the warning of water inrush from the floor of working face in coal mine. In order to study the evaluation technology for key monitoring area of water inrush warning of the floor of working face in coal mine, hydrogeological analysis, GIS spatial analysis and ANN prediction were used to …
Spatial Distribution And Formation Of Groundwater Hydrochemistry In Huainan Coalfield,
2019
College of Earth and Environment, Anhui University of Technology, Huainan 232001, China
Spatial Distribution And Formation Of Groundwater Hydrochemistry In Huainan Coalfield, Wang Zitao, Liu Qimeng, Liu Yu
Coal Geology & Exploration
In order to study the spatial distribution of groundwater in Huainan coalfield and the intensity of various hydrochemical actions, the coalfied is divided into the northern district with thicker loose beds and the southern district with thinner loose beds. Hydrochemical test data of main water-inrushing aquifers in 16 mines in these two areas were collected and statistically analyzed, ion combination method and Gibbs diagram were used to study the groundwater hydrochemical characteristics of each aquifer in north and south areas. The results indicate that TDS of aquifer is positively correlated with the burial thickness of unconsolidated formation. With the increase …
Similar Model Test And Mechanical Analysis Of Fault Structure,
2019
School of Mechanics&Civil Engineering, China University of Mining and Technology(Beijing), Beijing 100083, China
Similar Model Test And Mechanical Analysis Of Fault Structure, Song Yanqi, Wang Shilei, Sun Chuan, Hao Liangjun
Coal Geology & Exploration
The pre-existing fault specimens were made to confirm the actual stratum mechanical properties based on the similarity theory. Then the mechanism of failure mode of pre-existing fault was analyzed under the crack tip stress field theory. The results show that with the increase of load, the microcracks develop gradually and propagate, and the propagation path tends to the loading direction. In the process of crack propagation, multiple branch paths are generated, and then the cracks merge with each other to destroy the specimen. The stress field theory can be used to determine the newly generated fracture direction, which is consistent …
Fractal Theory-Based Investigation Of The Optimal Interval Of Minimum Pore Radius Of Sandstone,
2019
College of Construction Engineering, Jilin University, Changchun 130026, China
Fractal Theory-Based Investigation Of The Optimal Interval Of Minimum Pore Radius Of Sandstone, Xu Lulu, Dong Shuning, Dai Zhenxue, Xu Bin, Yin Shangxian, Zhou Yan, Chen Junjun
Coal Geology & Exploration
Permeability is a main parameter for evaluation of water conductivity of porous media, and it is a macroscopic feature of micro-pore structure of water-conducting media. To obtain the geometry parameters of microscopic pores, we performed scanning electron microscopy(SEM) on sandstone samples. The image processing techniques were also applied in calculation of different statistical parameters(e.g., fractal dimensions) and geometrical parameters. Then, fractal theory was introduced to investigate the influence of micro pore structure on permeability. At the same time, the minimum pore radius rmin interval acting on the seepage was obtained by the measured permeability values. This interval can be …
Fractal Characteristics Of Pores And Microfractures Of Coals With Different Structure And Their Effect On Permeability,
2019
College of Geology and Environment, Xi'an University of Science and Technology, Xi'an 710054, China; Key Laboratory of Coal Resources Exploration and Comprehensive Utilization, Ministry of Land and Resources, Xi'an 710021, China
Fractal Characteristics Of Pores And Microfractures Of Coals With Different Structure And Their Effect On Permeability, Ye Zhenni, Hou Enke, Duan Zhonghui, Wen Qiang, Huang Meitao, He Dan
Coal Geology & Exploration
The characteristics of pores and fractures in coal are the basis to study permeability. In this study, the micro-pores and fractures of coal samples with different structure taken from Guojiahe coal mine were analyzed using mercury injection experiment and scanning electron microscope. The micro-pores and fractures of intact coal and cataclastic coal samples were quantitatively analyzed by using Menger sponge and box-counting dimension. The comprehensive fractal dimension was calculated by pore volume weights. Based on fractal theory, the relationship between fractal dimension of coal samples and coal permeability have been discussed. The results show that brittle deformation adds complexity of …
The Discovery And Geological Significance Of Coal-Formed Graphite In Chongyi Coal Mine In Jiangxi Province,
2019
College of Geoscience and Surveying Engineering, China University of Mining and Technology(Beijing), Beijing 100083, China
The Discovery And Geological Significance Of Coal-Formed Graphite In Chongyi Coal Mine In Jiangxi Province, Li Yang, Wang Lu, Cao Daiyong, Du Xin, Zhao Meng, Liu Liming, Wei Yingchun
Coal Geology & Exploration
In order to study the characteristics of coal-formed graphite in Chongyi mine, Jiangxi Province, the coal in Laoshan Section of Upper Permian Longtan Formation in Chongyi mining area was tested and analyzed by means of optical microscope, X-ray diffraction(XRD), Raman spectroscopy and HRTED. The test results showed that the graphitization maceral could be observed under the optical microscope. The XRD diffraction pattern showed a graphite diffraction peak of d002, and the Raman spectrum showed a characteristic peak of graphite(G peak) with sharp peak shape. Multilayer ordered structure of carbon layer was observed by high resolution transmission electron microscope, …
Test Of The Influence Of Dynamic Water Grouting Diffusion Radius Of Fractures In Rock,
2019
School of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an 710054, China
Test Of The Influence Of Dynamic Water Grouting Diffusion Radius Of Fractures In Rock, Gu Shuancheng, Sun Guanlin, Su Peili, Li Jinhua
Coal Geology & Exploration
Water-cement ratio and grouting pressure are the key factors in the design of hydrodynamic grouting. In this paper, based on the self-designed simulated fissure hydrodynamic grouting indoor test platform, the dynamic water grouting test was carried out, the diffusion mode of the slurry in fractures was discussed. The relationship among the diffusion radius of pure cement slurry, the grouting pressure and water-cement ratio was analyzed. The experimental results were verified by computational fluid dynamics software. The results show that the diffusion mode of the slurry is partition diffusion. When the grouting pressure is constant, the diffusion radius is inversely proportional …
Lbfgs Csamt 1d Inversion Of Limited Memory Based On Boundary Constraint And Its Application,
2019
Huabei Oil Reservoir, CNPC, Renqiu 062552, China
Lbfgs Csamt 1d Inversion Of Limited Memory Based On Boundary Constraint And Its Application, Tang Chuanzhang, Cheng Jianzhong, Yan Liangjun, Feng Guangye, Zhou Lei, Xu Fengjiao
Coal Geology & Exploration
CSAMT is characterized by time-consuming calculation and low accuracy. The conventional inversion method has simple boundary processing, needs big memory, it is difficult to have accurate search direction, influencing severely the effect of inversion. In order to achieve rapid and high-precision forward modeling of CSAMT, to improve the boundary processing method, to reduce memory usage, to optimize the searching direction to reduce the times of iterative inversion, LBFGS CSAMT 1D inversion method based on boundary constraint and limited memory was proposed. Firstly in CSAMT forward modeling, double-precision and parallel algorithm was adopted, realizing rapid and high-precision calculation of the horizontal …
Calibration And Experiment Of Mine Electromagnetic Lwd Gamma Logging Tool,
2019
Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
Calibration And Experiment Of Mine Electromagnetic Lwd Gamma Logging Tool, Wang Xiaolong, Jiang Bici, Wang Kaibin
Coal Geology & Exploration
In order to effectively identify coal seam, roof and floor, mine electromagnetic LWD gamma logging tool was developed for directional drilling in coal mine. The calibration coefficient of the instrument can be obtained by natural gamma logging scale, and various measurement curves of mine electromagnetic LWD gamma logging tool can be obtained by standard well test and crossing borehole test in coal mine. Through comparing with the gamma curve of standard well and analyzing the geological data of the crossing borehole, the measurement result accuracy of mine electromagnetic LWD gamma logging tool is verified. The application test in underground coal …
Stability Of Cement-Based Grouting Slurry And Test Of Its Bleeding Law,
2019
College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China; Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China; Shaanxi Key Laboratory of Coal Mine Water Hazard Prevention and Control Technology, Xi'an 710077, China
Stability Of Cement-Based Grouting Slurry And Test Of Its Bleeding Law, Xu Bin, Dong Shuning, Xu Lulu, Zhou Yan, Chen Junjun, Dai Zhenxue, Wang Hao
Coal Geology & Exploration
To better understand the stability performance and bleeding property of cement-based grouting slurry, a new test device was improved to get the separated-water thickness value of slurry samples at every time, and these samples were made and sorted according to the certain proportion of the water-solid ratio(0.6:1 to 3:1), fly ash content(0-90%) and sodium silicate content(0-12%). The growth theory for separated-water thickness was introduced, and the growth curves for all formulations were plotted. The slurry stability measurement method was classified, and the equivalence relation between the direct measurement method of slurry stability and the indirect measurement method was verified. The …
Identification Model Of The Independence Right-Fuzzy Variable Theory Of Water Inrush Source,
2019
College of Geoscience and Surveying Engineering, China University of Mining and Technology, Beijing 100083, China; National Engineering Research Center of Coal Mine Water Hazard Controlling, Beijing 100083, China
Identification Model Of The Independence Right-Fuzzy Variable Theory Of Water Inrush Source, Dong Donglin, Li Xiang, Lin Gang, Bian Jianling, Cao Chenglong, Wu Heng
Coal Geology & Exploration
In the process of coal mining, mine water hazard accidents occur frequently. In order to find out the water source of mine water inrush quickly and accurately, and reduce the harm caused by mine water inrush to coal mine production, taking Zhaogezhuang mine as an example, and the method of combining independent weight coefficient with fuzzy variable theory was used to select six kinds of hydrochemical indexes of Na+, Ca2+, Mg2+, Cl-, SO42- and HCO3-, 20 sets of water sample data of Zhaogezhuang mine were analyzed and …
Experimental Study Of Three-Component Down-Hole Tem For Detecting Water-Filled Goaf,
2019
Xi'an Research Institute Co. Ltd., China Coal Technology and Engineering Group Corp., Xi'an 710077, China
Experimental Study Of Three-Component Down-Hole Tem For Detecting Water-Filled Goaf, Yao Weihua, Wang Peng, Li Mingxing, Su Chao, Cheng Siyuan
Coal Geology & Exploration
The borehole geophysical prospecting method is a research hotspot in recent years. Considering that the down-hole transient electromagnetic method used in metal mines has the characteristics of long radial detection distance and less susceptible to surface electromagnetic interference, it is applied to the exploration of water-filled goaf in coal mines. Three-dimensional finite-difference time-domain(FDTD) algorithm is used to simulate the total field response and abnormal response of the goaf model with different orientations of boreholes. The total field three-component could reflect the water-filled goaf obviously, and the abnormal field three-component shape combination can distinguish the azimuth of the abnormal body. Based …
Micro Ct-Based Meticulous Characterization Of Porosity Evolution Of Coal In The Process Of Biodegradation,
2019
School of Energy Science and Engineering, Henan Polytechnic University, Jiaozuo 454000, China
Micro Ct-Based Meticulous Characterization Of Porosity Evolution Of Coal In The Process Of Biodegradation, Dong Zhiwei, Guo Hongyu, Xia Daping, Liu Xile, Bai Yang, Zhao Guojun
Coal Geology & Exploration
To explore the bio-permeability enhancing effect via methanogen treatment on different rank coals after anaerobic fermentation, micro-CT was used to analyze the change characteristics of pore structure of coal before and after biodegradation. At the same time, the adsorption characteristics of methanogens on the coal surface after anaerobic biodegradation were observed by scanning electron microscopy to analyze the reasons for the effect difference of biological transformation of different rank coals. The results show that the porosity and total throat length of the coal samples biodegraded increase and the connectivity of the pores is enhanced, it is indicated that coal samples …
Comprehensive Outburst Prevention Technology Of Outburst-Prone Coal Seam Uncovered By Crossdrift In Hongshan Coal Mine,
2019
School of Mines, Liaoning Technical University, Fuxin 123000, China; State Key Laboratory of Coal Resources and Safe Mining, Xuzhou 221008, China; State Key Laboratory of Water Resource Protection and Utilization in Coal Mining, Beijing 100011, China
Comprehensive Outburst Prevention Technology Of Outburst-Prone Coal Seam Uncovered By Crossdrift In Hongshan Coal Mine, Wang Beifang, Liang Bing, Zhang Jing, Chi Haibo, Huang Pujiang
Coal Geology & Exploration
Coal and gas outburst is a complex geo-dynamic disaster induced by a coal seam uncovered by crossdrift, threatens the safety and efficient production of coal mines seriously. For this, Hongshan coal mine was selected as engineering background to simulate mechanical response characteristics of surrounding rock during uncovering No.12 coal seam in a gas bursting hazardous zone with FLAC3D software. Then the outburst mechanism during uncovering a coal seam by a crossdrift was revealed, and comprehensive outburst prevention technology combining mine gas pre-drainage and improved metal skeleton was put forward. The results showed that the abutment pressure ahead of the …
Reasons Of Low Yield And Stimulation Measures For Vertical Cbm Wells In High-Rank Coal,
2019
Shanxi CBM Branch Company, PetroChina Huabei Oilfield, Changzhi 046000, China
Reasons Of Low Yield And Stimulation Measures For Vertical Cbm Wells In High-Rank Coal, Jia Huimin, Hu Qiujia, Qi Kongjun, Liu Chunchun, Fan Bin, He Jun
Coal Geology & Exploration
The CBM production is usually low and development effect is poor in China, which are mainly due to the poor adaptability of the stimulation measures to the geological conditions. This article, based on the low-yield reasons for vertical CBM wells in Zhengzhuang block in southern Qinshui basin, puts forth corresponding stimulation measures, analyzes the mechanism and the geological adaptability, optimizes the parameters of specific stimulation measures and carries out pilot test. The research and practices show that in deeply buried area, fractures are difficult to form, and re-fracturing technology can make the fracture turn and increase the crack length, which …
