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Full-Text Articles in Engineering
Numerical Simulations And Wavefield Analysis Of In-Seam Wave Advance Detection In Viscoelastic Media, He Dixiu, Ji Guangzhong, Jiao Wenjie, Zhang Yawei, Yu Kun
Numerical Simulations And Wavefield Analysis Of In-Seam Wave Advance Detection In Viscoelastic Media, He Dixiu, Ji Guangzhong, Jiao Wenjie, Zhang Yawei, Yu Kun
Coal Geology & Exploration
In-seam waves are commonly applied to the advance detection of hidden faults in front of mining faces. However, coal seams, which have viscoelasticity actually, imposing absorptive and attenuation effects on in-seam waves. To investigate the wave field characteristics and propagation patterns of in-seam waves in viscoelastic coal seam media, this study built a three-dimensional geological model of coal measures with faults based on Kelvin-Voigt’s first-order velocity-stress equation. Using this equation, three-dimensional finite-difference numerical simulation was carried out. The results indicate that (1) for reflected in-seam waves in viscoelastic media, which exhibit high energy attenuation, their propagation and attenuation characteristics are …
Influence Of High In-Situ Stress Areas In The Coal Seam Roofs On Microseism-Based Tomographic Inversion, Liu Kaihang, Feng Lei, Yun Meihou, Cao Yunxing, Tian Lin
Influence Of High In-Situ Stress Areas In The Coal Seam Roofs On Microseism-Based Tomographic Inversion, Liu Kaihang, Feng Lei, Yun Meihou, Cao Yunxing, Tian Lin
Coal Geology & Exploration
High in-situ stress areas in the coal seam roofs are prone to induce mine dynamic hazard such as rock bursts. To meet the demand for safe coal mining, this study achieved real-time monitoring and swift early warning of high in situ stress areas. Specifically, based on data transmitted from microseismic stations in real time, this study conducted the inversion of the wave velocities in coal seams and rocks using a fast three-dimensional (3D) tomographic inversion algorithm. The accuracy of tomographic inversion results directly determines the judgment on the locations of high in situ stress areas. Therefore, by building a 3D …
Forward Modeling Of Amplitude Variation With Offset And Azimuth (Avoa) Response For Fracture Parameters Of Horizontal Transversely Isotropic Coal Seams, Wu Haibo, Liu Qinjie, Wang Jinchao, Li Zhi, Bai Ze, Xi Chaoqiang
Forward Modeling Of Amplitude Variation With Offset And Azimuth (Avoa) Response For Fracture Parameters Of Horizontal Transversely Isotropic Coal Seams, Wu Haibo, Liu Qinjie, Wang Jinchao, Li Zhi, Bai Ze, Xi Chaoqiang
Coal Geology & Exploration
Fractures serve as a key factor controlling the permeability of coal seams and play a crucial role in the exploration and exploitation of coalbed methane. This study focuses on the Amplitude Variation with offset and Azimuth (AVOA) response mechanisms of the fracture parameters of horizontal transversely isotropic (HTI) coal seams. To this end, this study calculated the equivalent elastic modulus of coal seams with vertical dry and fluid-saturated fractures using the Mori-Tanaka model and the Brown-Korringa anisotropic fluid substitution equation, respectively. Moreover, based on the petrophysical characterization of fractures in coal seams and the forward modeling using the HTI coal …
Study On Mesozoic Magmatic Intrusion And Paleozoic Multi-Mineral Genesis Mechanism In Huanghebei Coalfield，Shandong Province, Wang Huaihong, Shen Lijun, Wang Dongdong, Zhu Yuzhen, Li Zengxue, Wang Yongjun, Mao Qiang
Study On Mesozoic Magmatic Intrusion And Paleozoic Multi-Mineral Genesis Mechanism In Huanghebei Coalfield，Shandong Province, Wang Huaihong, Shen Lijun, Wang Dongdong, Zhu Yuzhen, Li Zengxue, Wang Yongjun, Mao Qiang
Coal Geology & Exploration
Accumulation of various minerals is common in strata, especially in areas invaded by magma, which is more conducive to the generation and preservation of various minerals and greatly improves the exploration benefit and development value of mineral resources. Taking Huanghebei Coalfield in Shandong Province as an example, this paper studies the genesis mechanism of Mesozoic rock intrusion and Paleozoic multiple minerals(coal, coal-bed methane, coal-measure shale gas and rich iron ore). Research shows that: Huanghebei Coalfield Carboniferous-Permian Period tectonic conditions and sedimentary environment are conducive to the development of coal seam, and coal seam distribution in the plane is characterized by …
Numerical Analysis On Csw Fracturing Behavior Of Coal Seam Under Constraint Of Geological And Engineering Conditions, Qin Yong, Li Hengle, Zhang Yongmin, Zhao Youzhi, Zhao Jincheng, Qiu Aici
Numerical Analysis On Csw Fracturing Behavior Of Coal Seam Under Constraint Of Geological And Engineering Conditions, Qin Yong, Li Hengle, Zhang Yongmin, Zhao Youzhi, Zhao Jincheng, Qiu Aici
Coal Geology & Exploration
As a revolutionary technology for rock stratum reformation, the controllable shock wave(CSW) fracturing technology has achieved remarkable effect in coal seam reconstruction, and application exploration in the field of coal safety mining has been carried out. However, the previous understanding of the basic CWS fracturing rules under the constraints of geological engineering factors is insufficient due to the limitation of experimental and field monitoring conditions, which restricts the exploration of the fracturing mechanism and the optimization of the field operation parameters. In view of this, based on the description of CSW coal seam reformation and its engineering scientific problems, the …
The Effect Of Viscoelasticity And Velocity Anisotropy On The Reflections Of A Thin Bed, Chen Benchi, Wang Chao, Chen Changxing, Shi Lei
The Effect Of Viscoelasticity And Velocity Anisotropy On The Reflections Of A Thin Bed, Chen Benchi, Wang Chao, Chen Changxing, Shi Lei
Coal Geology & Exploration
The coal seam is a typical thin bed characterized by much lower elastic impedance than that of the surrounding rock. Coal seam has viscoelasticity and velocity anisotropy and its reflection amplitude changes with frequency. In order to analyze the effect of viscoelasticity and velocity anisotropy on seismic responses of a thin bed, this paper aims at a thin-bed model with strong impedance contrast and simulates seismic responses under three different assumptions, elastic and velocity isotropy, viscoelastic and velocity isotropy, and viscoelastic and velocity anisotropy, through numerical simulation method based on wave equations. Comparison of these seismic reflections shows that the …
Corrosion Behavior Analysis Of Sucker Rod For Coalbed Methane Wells In The Eastern Block Of Ordos Basin, Pang Bin, Wang Hanxiang, Lan Wenjian
Corrosion Behavior Analysis Of Sucker Rod For Coalbed Methane Wells In The Eastern Block Of Ordos Basin, Pang Bin, Wang Hanxiang, Lan Wenjian
Coal Geology & Exploration
In order to make clear the corrosion rule of sucker rod for coalbed methane wells in the eastern block of Ordos basin, the paper summarizes the corrosion types and corrosion intensities of the sucker rod, based on the test of produced gas, produced water, corrosion products and weight loss of sucker rod. The paper analyzes the effect of different drainage stages, coal seam and mineralization degree of water on the corrosion. The results of the research indicate that corrosion is mainly caused by CO2 and H2S originated from No.5 coal seam and No.11 coal seam. The corrosion …
Instability Mechanism And Anti-Sloughing Drilling Fluid Technique For Deep Coal Seam Of Tarim Basin, Li Heng, He Shiming, Tang Ming, Li Ning, Yang Pei, Zhang Zhen
Instability Mechanism And Anti-Sloughing Drilling Fluid Technique For Deep Coal Seam Of Tarim Basin, Li Heng, He Shiming, Tang Ming, Li Ning, Yang Pei, Zhang Zhen
Coal Geology & Exploration
In view of the complicated problems of drilling fluid leakage and hole collapse during the drilling of deep coalbed in Tarim basin, the microstructure and physical and chemical properties of coal were tested by vitrinite reflectance analysis, X ray diffraction and scanning electron microscope, and the mechanism of coal seam instability was confirmed. The fixed carbon content of the coal exceeds 60%, the vitrinite reflectance is greater than 1.1%, and coal have high degree of coalification, is brittle and easy to break. The total amount of clay mineral is less than 25%, and there is no strong water-sensitive mineral montmorillonite …