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- Numerical simulation (87)
- Coalbed methane (47)
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- Permeability (27)
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- Underground coal gasification (UCG) (13)
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- Machine learning (12)
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- Fractal dimension (11)
- Helium (11)
- Intelligent mining (11)
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Articles 1 - 30 of 1799
Full-Text Articles in Environmental Sciences
Table Of Contents, The Editors
Resilience-Oriented Geological Safeguards For Damage Mitigation In Coal Resource Exploitation, Wang Shuangming, Sun Qiang, Yan Meixin, Miao Lintian, Liu Lang, Qiao Junwei, Niu Chao, Geng Jishi, Fang Chenxi, Zhang He, Xiao Lele, Li Shibo
Resilience-Oriented Geological Safeguards For Damage Mitigation In Coal Resource Exploitation, Wang Shuangming, Sun Qiang, Yan Meixin, Miao Lintian, Liu Lang, Qiao Junwei, Niu Chao, Geng Jishi, Fang Chenxi, Zhang He, Xiao Lele, Li Shibo
Coal Geology & Exploration
Background Coal remains a fundamental component of China’s energy security system. With the westward shift of coal development and continuous expansion into deeper strata, coal mining is confronted with increasingly complex geological conditions and growing ecological constraints. Geological damage induced by mining disturbance has evolved from isolated geological issues into a coupled Earth-system problem involving the lithosphere, hydrosphere, pedosphere, atmosphere, and biosphere, characterized by uncertainty, hysteresis, concealment, and cross-scale accumulation. Resilience-based damage mitigation emphasizes reducing the probability, intensity, and recovery costs of geological damage through proactive identification, dynamic regulation, damage suppression, and post-disturbance restoration under mining disturbance and external environmental …
Key Technologies And Their Application Of Vertical Large Models For Geological Guarantee In Coal Mining, Liu Zaibin, Fan Tao, Liu Borui, Chen Changyuan, Li Guihong, Li Wei, Jing Xiaotian, Li Xiping, Du Yiming
Key Technologies And Their Application Of Vertical Large Models For Geological Guarantee In Coal Mining, Liu Zaibin, Fan Tao, Liu Borui, Chen Changyuan, Li Guihong, Li Wei, Jing Xiaotian, Li Xiping, Du Yiming
Coal Geology & Exploration
Background General-purpose large language models (LLMs) have remarkable capabilities in natural language understanding and complex-task reasoning. However, when applied to geological guarantee in coal mining, these models still suffer from several inherent limitations, including insufficient professional geological knowledge, limited insights into industrial terminology, and inadequate integration of engineering logic and rules. Consequently, they face challenges in accurately capturing domain-specific knowledge and reasoning mechanisms required for geological interpretation, early warning of disasters, and decision-making for disaster prevention and control. These issues lead to limited applicability and reliability of general-purpose LLMs. On the other hand, geological guarantee in coal mining involves multi-source …
Mechanisms And Implications Of The Novel Cast Model Of Coal Graphitization, Wang Shaoqing, Zhang Jingzhe, Zhang Xiaomei, Wang Xiaoshuai, Chen Hao, Wang Xiaoling, Li Wu, Tang Yuegang
Mechanisms And Implications Of The Novel Cast Model Of Coal Graphitization, Wang Shaoqing, Zhang Jingzhe, Zhang Xiaomei, Wang Xiaoshuai, Chen Hao, Wang Xiaoling, Li Wu, Tang Yuegang
Coal Geology & Exploration
Objective and Methods Coal graphitization is a multi-stage process with abrupt changes rather than linear evolution. So far, its inherent driving mechanisms have not yet been fully elucidated. Notably, twisted graphene was observed in the process of coal graphitization in 2025, providing a new opportunity to reveal the essence of this structural transformation. Results and Conclusions By combining previous research results, this study proposes a novel coal graphitization model that consists of condensation, alignment, stacking, and twisting (CAST). The four parts of the CAST model are organically integrated, collectively forming a continuous and dynamic evolutionary process. Most especially, no absolute …
Microstructure Evolution Characteristics Of Coal Briquettes During Hot Pressing Carbonization And A Temperature Control Method, Gan Qingqing, Xu Jiang, Peng Shoujian, Cai Guoliang
Microstructure Evolution Characteristics Of Coal Briquettes During Hot Pressing Carbonization And A Temperature Control Method, Gan Qingqing, Xu Jiang, Peng Shoujian, Cai Guoliang
Coal Geology & Exploration
Objective Coal briquettes used for physical simulations of gas disasters in coal mines generally exhibit low strength and high permeability. To address this challenge, this study developed a new hot pressing process and a temperature control method to optimize the mechanical and seepage performance of coal briquettes. Methods First, an optimal mixing ratio scheme was determined based on the Horsfield close-packing theory, and coal briquettes were prepared at different temperatures using an independently developed hot pressing system. Subsequently, the microstructure evolution patterns of the hot-pressed coal briquettes were characterized using an X-ray diffractometer (XRD), an X-ray photoelectron spectrometer (XPS), a …
3d Geological Modeling And Its Application For Steeply Dipping Coal Seams In The Miquan Area, Xinjiang, Wu Luofei, Li Yong, Zhang Weiqi, Han Yiyang, Zhang Jie, Cao Mingliang, Li Qiang
3d Geological Modeling And Its Application For Steeply Dipping Coal Seams In The Miquan Area, Xinjiang, Wu Luofei, Li Yong, Zhang Weiqi, Han Yiyang, Zhang Jie, Cao Mingliang, Li Qiang
Coal Geology & Exploration
Background Influenced by multi-stage compression from the North Tianshan and Bogda mountains, the southern margin of the Junggar Basin in Xinjiang exhibits the widespread development of steeply dipping coal seams. The extreme stratigraphic occurrence, combined with complex structural superimposition styles, poses significant challenges to the fine-scale characterization of these coal seams. Correspondingly, the planar and regional distribution patterns of gas content in these coal seams remain poorly understood, rendering it difficult to effectively determine the sweet spots of coalbed methane (CBM). Methods Focusing on the Miquan area, Xinjiang, this study investigated the methodology for 3D geological modeling of representative steeply …
Evolutionary Characteristics And Fine-Scale Zoning Of Overburden Fractures For Pressure-Relief Mining Of Soft Coal Seams, Wang Long, Deng Zhiliang, Zhang Zongxiang, Guo Baohua, Tan Hongchen, Zhao Pengtao, Hu Longsheng
Evolutionary Characteristics And Fine-Scale Zoning Of Overburden Fractures For Pressure-Relief Mining Of Soft Coal Seams, Wang Long, Deng Zhiliang, Zhang Zongxiang, Guo Baohua, Tan Hongchen, Zhao Pengtao, Hu Longsheng
Coal Geology & Exploration
Objective During the mining of coal seam groups, substantial gas is prone to rush into the mining face from adjacent coal seams through interconnected mining-induced fractures. This poses a threat to safe coal mining. Under pressure-relief mining of soft coal seams, their low permeability and high stress sensitivity present challenges to the successive mining of protective and protected coal seams. Specifically, mechanisms behind the overburden fracture evolution remain poorly understood, and it is difficult to identify preferential pathways for gas migration accurately. Methods This study investigated coal seam groups in the Jiahe mining area of Hunan Province as the engineering …
Spatial Topological Configurations Of Cleats And Geometrical Quantitative Characterization Of Matrix Blocks In Deep Coal Seams, Shen Jian, Li Wei, Tian Yongjing, Ma Tianyu, Zhang Hewei, Dong Jiying, Zhu Peipei
Spatial Topological Configurations Of Cleats And Geometrical Quantitative Characterization Of Matrix Blocks In Deep Coal Seams, Shen Jian, Li Wei, Tian Yongjing, Ma Tianyu, Zhang Hewei, Dong Jiying, Zhu Peipei
Coal Geology & Exploration
Objective Cleats in deep coal seams are characterized by strong heterogeneity, and their topological configurations, as well as their topological relationships with matrix blocks, remain poorly understood. On the other hand, the assumptions regarding the size and geometry of matrix blocks adopted in representative reservoir structure models and numerical simulations do not fully reflect actual reservoir conditions. Methods Deep coal cores collected from the northeastern Ordos Basin were investigated in this study. Using CT scanning and topological theory, a multi-dimensional topological parameter system was established to characterize cleats in deep coal seams. Furthermore, four topological configurations of cleats in deep …
Stable Isotope-Based Origin Identification And Enrichment Zone Division Of Medium- To Low-Rank Coalbed Methane, Wang Qiong, Xu Fengyin, Ren Pengfei, Xu Hao, Lu Pengda, Hu Han, Zhou Siyuan
Stable Isotope-Based Origin Identification And Enrichment Zone Division Of Medium- To Low-Rank Coalbed Methane, Wang Qiong, Xu Fengyin, Ren Pengfei, Xu Hao, Lu Pengda, Hu Han, Zhou Siyuan
Coal Geology & Exploration
Objective Medium-to low-rank coalbed methane (CBM) exhibits complex origins with significant vertical differentiation, leading to unclear origin identification and enrichment patterns. This study aims to determine the genetic mechanisms, enrichment patterns, and efficient exploitation pathways of medium- to low-rank CBM. This will help improve the theoretical system for the exploration and exploitation of such CBM. Methods CBM data from 14 typical low- to medium-rank coalfields and coal-bearing basins across the world were comprehensively analyzed, including CBM compositions C1/(C2+C3), carbon and hydrogen isotopes of CH4 (δ13C-CH4 and δD-CH4 …
Dynamic-To-Static Elastic Parameter Conversion Models For Coals Under Temperature-Pressure Coupling: A Case Study Of The No. 8 Coal Seam In The Daning-Jixian Block, Zhang Wei, Wu Peng, Liu Conghui, Zhang Sidun, Sun Xuedong, Yang Haixing, Ma Zhuang, Shi Rui, Shen Jian
Dynamic-To-Static Elastic Parameter Conversion Models For Coals Under Temperature-Pressure Coupling: A Case Study Of The No. 8 Coal Seam In The Daning-Jixian Block, Zhang Wei, Wu Peng, Liu Conghui, Zhang Sidun, Sun Xuedong, Yang Haixing, Ma Zhuang, Shi Rui, Shen Jian
Coal Geology & Exploration
Objective Existing dynamic-to-static elastic parameter conversion models for coals fail to fully account for the actual in situ pressure and temperature conditions of deep reservoirs. This leads to significant deviations in directly evaluating the mechanical properties of reservoirs using log-derived dynamic parameters. To address this challenge, this study investigated dynamic-to-static elastic parameter conversion under the in situ stress and geotemperature conditions of strata. Accordingly, high-precision parameter conversion models were established. Methods This study examined coal samples from the No. 8 coal seam at a burial depth of approximately 1200 m in the Daning-Jixian block along the eastern margin of the …
A Geochemical Evaluation Method For Geological Sweet Spots Of Marine-Continental Transitional Shale Gas: A Case Study Of The Shan$^3_2 $ Sub-Member, Eastern Margin Of The Ordos Basin, Zhu Xingcheng, Li Yong, Lu Jungang, He Qingbo, Li Shuxin, Xiao Zhenglu, Li Xiang, Jiang Qijun
A Geochemical Evaluation Method For Geological Sweet Spots Of Marine-Continental Transitional Shale Gas: A Case Study Of The Shan$^3_2 $ Sub-Member, Eastern Margin Of The Ordos Basin, Zhu Xingcheng, Li Yong, Lu Jungang, He Qingbo, Li Shuxin, Xiao Zhenglu, Li Xiang, Jiang Qijun
Coal Geology & Exploration
Background China boasts abundant marine-continental transitional shale gas resources. However, marine-continental transitional shales in the country exhibit complex geological conditions characterized by rapid lateral facies transition, vertical superimposition of multiple lithologies, and small single-layer thickness. These characteristics pose a challenge to shale gas sweet spot prediction. Therefore, establishing a sweet spot grading and evaluation system tailored to these shales is of great significance for guiding decision-making in hydrocarbon exploration and supporting large-scale production. Methods Based on core observations, this study systematically evaluated the geochemical characteristics of marine-continental transitional shales in the 3rd submember of the 2nd member of the Permian …
Sources And Occurrence Patterns Of Hydrocarbons In The Surrounding Rocks Of Coal Seams: A Case Study Of The Jurassic Yan'an Formation In The Xinzhuang Mine Field, Longdong Area, Zhang Peng, Chen Dongdong, Zhao Junfeng, Zheng Kaige, Wang Chunxin, Zhou Xingtian
Sources And Occurrence Patterns Of Hydrocarbons In The Surrounding Rocks Of Coal Seams: A Case Study Of The Jurassic Yan'an Formation In The Xinzhuang Mine Field, Longdong Area, Zhang Peng, Chen Dongdong, Zhao Junfeng, Zheng Kaige, Wang Chunxin, Zhou Xingtian
Coal Geology & Exploration
Objective and Methods This study aims to ascertain abnormal hydrocarbon outflows from the surrounding rocks of coal seams in the Jurassic Yan'an Formation within the Xinzhuang mine field in the Longdong area, southwestern Ordos Basin. Based on the fundamental principles of petroleum geology, sedimentology, and coal geology, this study systematically analyzed the sources, occurrence patterns, and primary controlling factors of hydrocarbons in the surrounding rocks of coal seams using methods including core observation, sample analysis, and statistical mapping. Results and Conclusions In the Xinzhuang mine field, hydrocarbon outflows are primarily identified in the floor of the No. 8 coal seam …
Investigating Seepage In Rough Porous Media Fractures Using Fractional Brownian Motion Simulation, Liu Weitao, Kong Debin, Mao Qingfu, Zhao Jiyuan, Gu Yulong, Zhang Xiao
Investigating Seepage In Rough Porous Media Fractures Using Fractional Brownian Motion Simulation, Liu Weitao, Kong Debin, Mao Qingfu, Zhao Jiyuan, Gu Yulong, Zhang Xiao
Coal Geology & Exploration
Background Natural rock fractures are often partially filled with permeable materials such as silt and minerals under long-term geological and hydraulic actions, forming complex structures containing unfilled voids. The seepage characteristics of such fractures significantly influence petroleum extraction, mine water prevention, and the stability of underground engineering projects. Methods To reveal the underlying seepage mechanisms, this study generated rough profiles of unfilled voids with different fractal dimensions based on Fractional Brownian Motion. A theoretical expression for the overall permeability of partially filled fractures was derived, and a coupled free flow–porous medium flow numerical model was established. This framework was used …
Key Technologies And Engineering Practices For Green Drainage Of The Jurassic Burnt Rock-Hosted Water In The Shenfu Mining Area, Ji Zhongkui, Mou Lin, Wang Hai, Zhu Kaipeng, Zhao Kaixing, Chen Pan, Xue Xiaoyuan, Han Qiang, He Bo, Wang Fuming
Key Technologies And Engineering Practices For Green Drainage Of The Jurassic Burnt Rock-Hosted Water In The Shenfu Mining Area, Ji Zhongkui, Mou Lin, Wang Hai, Zhu Kaipeng, Zhao Kaixing, Chen Pan, Xue Xiaoyuan, Han Qiang, He Bo, Wang Fuming
Coal Geology & Exploration
Objective In the northern part of Shaanxi Province, coal mining has led to a pronounced contradiction between coal mining and water conservation, along with a serious threat to China’s ecological redline. These challenges necessitate transforming the mine water drainage pattern in coal mines. Green mine water drainage represents a key approach to achieving coordinated coal-water production in areas containing burnt rocks. Methods Focusing on the conservation-oriented utilization of the Jurassic burnt rock-hosted water in a coal mine within the Shenfu mining area, this study explored a solution to coordinated coal-water production in areas affected by burnt rock-hosted water from the …
Mine Water Storage In Deep Strata: Temperature Responses And The Quantitative Identification Of Primary Permeable Intervals, Xue Jiankun, Wang Shuangming, Zhang Pingsong, Wang Xiaodong, Han Le, Wang Zhizhou, Wang Yutong, Wang Zhibo
Mine Water Storage In Deep Strata: Temperature Responses And The Quantitative Identification Of Primary Permeable Intervals, Xue Jiankun, Wang Shuangming, Zhang Pingsong, Wang Xiaodong, Han Le, Wang Zhizhou, Wang Yutong, Wang Zhibo
Coal Geology & Exploration
Background Storage in deep strata represents an effective approach to treating high-salinity mine water in mining areas of western China. For this technology, the use of directional wells can significantly enhance water injection efficiency, while selecting primary permeable intervals with high injectivity as drilling targets is key to its successful implementation. However, the accurate identification of these intervals in deep strata remains challenging. Methods By analyzing the wellbore temperature variations in the injection well during water injection, a qualitative model was developed to evaluate primary permeable intervals based on wellbore temperature curves. Following the principles of momentum and energy conservation, …
Field Tests On The Capillary Barrier Effect Of Covers For Comprehensive Utilization Of Solid Waste In Waste Dumps, Duan Xu, Chen Chuangchuang, Qiu Xun, Wang Bo, Shi Luyu, Yan Hanyang, Zou Yu, Qu Jin, Hu Zhaojiang
Field Tests On The Capillary Barrier Effect Of Covers For Comprehensive Utilization Of Solid Waste In Waste Dumps, Duan Xu, Chen Chuangchuang, Qiu Xun, Wang Bo, Shi Luyu, Yan Hanyang, Zou Yu, Qu Jin, Hu Zhaojiang
Coal Geology & Exploration
Background In the arid and semi-arid regions of northwestern China, the open-pit waste dumps of mining areas suffer from severe water erosion and the limited water-holding capacities of shallow cover soils. This restricts the ecological restoration of abandoned mine lands. Capillary barrier covers can enhance the water-holding capacities of water storage layers due to the differential hydraulic properties at the interface between fine- and coarse-grained layers. However, both the feasibility of constructing layered covers by mixing solid waste slags from waste dumps with clay and the water regulation performance of the covers are yet to be verified in the field. …
An Experimental Study On The Compressive Shear Failure Characteristics Of Mining-Induced Fractured Rock Blocks In The Absence Of Lateral Confinement And Under Unilateral Confinement, Wang Wenxue, Zhang Shicheng, Li Linyang, Zhang Ruochen, Liang Yankun, Chang Jian, Pan Xuwei, Zhao Guizhang
An Experimental Study On The Compressive Shear Failure Characteristics Of Mining-Induced Fractured Rock Blocks In The Absence Of Lateral Confinement And Under Unilateral Confinement, Wang Wenxue, Zhang Shicheng, Li Linyang, Zhang Ruochen, Liang Yankun, Chang Jian, Pan Xuwei, Zhao Guizhang
Coal Geology & Exploration
Objective Rock bridges exert a controlling influence on the deformation, fracture field evolution, and structural stability of mining-induced fractured rock masses. Therefore, it is necessary to investigate their deformation and failure characteristics, as well as the underlying controlling mechanisms, under different confinement conditions. Such investigations will provide theoretical support for the safe mining of underground coal seams and the prevention and control of mining-induced disasters. Methods Mechanical models of fractured rock blocks containing rock bridges were established. Specimens with different fracture dip angles, rock bridge widths, and material strengths were prepared using rock-like materials. Furthermore, an independently developed compressive shear …
An Integrated Automated Parameter Optimization Method Based On Fdem And Isight For Rock Mass Engineering: A Case Study Of Pillar Stability Design, Zhu Defu, Gao Bolong, Xu Jiabo, Wang Deyu, Gao Peng, Li Yalin, Hu Wenshuo
An Integrated Automated Parameter Optimization Method Based On Fdem And Isight For Rock Mass Engineering: A Case Study Of Pillar Stability Design, Zhu Defu, Gao Bolong, Xu Jiabo, Wang Deyu, Gao Peng, Li Yalin, Hu Wenshuo
Coal Geology & Exploration
Background Conventional rock mass engineering design largely relies on empirical equations or numerical simulation schemes selected from a limited number of comparable cases, making it difficult to effectively balance multiple constraints such as safety, economic viability, and resource recovery. The finite-discrete element method (FDEM) based on the intrinsic cohesive zone model (ICZM) can effectively simulate the evolution of quasi-brittle materials from continuous to discontinuous behavior, rendering it particularly suitable for engineering issues involving highly discontinuous rock masses. Therefore, FDEM has become an important numerical analysis method in rock mass engineering. However, there remains an urgent need for a high-precision, integrated, …
An Image Recognition And Multi-Parameter Quantitative Characterization System For Fractures In Roadway Rocks, Xiong Yu, Jiang Lichun, Kong Dezhong, Li Jinzhu
An Image Recognition And Multi-Parameter Quantitative Characterization System For Fractures In Roadway Rocks, Xiong Yu, Jiang Lichun, Kong Dezhong, Li Jinzhu
Coal Geology & Exploration
Objective Conventional measurement methods for rock fractures suffer from low efficiency and high subjectivity. On the other hand, simple image recognition techniques struggle to achieve high-precision multi-parameter integrated analysis of rock fractures in complex roadway environments. To address these challenges, this study aims to develop an image recognition and multi-parameter quantitative characterization system for rock fractures. Methods At the core of the system is the formulation of a combined image preprocessing strategy. Specifically, fracture segmentation is conducted based on adaptive threshold binarization, isolated noise points are removed using morphological opening, and median filtering is introduced to perform the refined polishing …
Selection And Verification Of Optimal Key Parameters Of Ultra-Wideband Radars For Life Detection In Coal-Rock Shielding Environments In Coal Mines, Huang Yuan, Zheng Xuezhao, Wen Hu, Jin Feiyang, Xu Chengyu, Liu Yin, Ding Wen
Selection And Verification Of Optimal Key Parameters Of Ultra-Wideband Radars For Life Detection In Coal-Rock Shielding Environments In Coal Mines, Huang Yuan, Zheng Xuezhao, Wen Hu, Jin Feiyang, Xu Chengyu, Liu Yin, Ding Wen
Coal Geology & Exploration
Objective and Methods Ultra-wideband (UWB) radars can transmit electromagnetic waves that penetrate coal and rock media, thereby addressing the challenge of detecting and localizing personnel trapped in shielding environments during mine collapse. However, key parameters for UWB radar detection are difficult to determine due to complex mine environments, diverse media, and unclear dispersion characteristics. To deal with this issue, this study determined the frequency-dependent dielectric properties of various coal and rock media, as well as human tissues, through experiments and fitting. In combination with actual rescue scenarios, this study established the electromagnetic equivalent model of shielding environments in coal mines. …
A Method Of Reflected In-Seam Wave Imaging Based On The Structural Similarity Index Of Adjacent Gathers, Wang Ji, Wei Zhongli, Ye Hongxing, Wu Guoqing, Liu Shuo, Niu Huan, Su Xiaoyun
A Method Of Reflected In-Seam Wave Imaging Based On The Structural Similarity Index Of Adjacent Gathers, Wang Ji, Wei Zhongli, Ye Hongxing, Wu Guoqing, Liu Shuo, Niu Huan, Su Xiaoyun
Coal Geology & Exploration
Background Reflected in-seam wave detection represents a major method for exploring geological anomalies in underground coal mines. This method is well suited to detecting concealed structures (e.g., faults and collapse columns) within coal seams in the tunneling direction of roadways or along their side walls. In recent years, to meet the safety requirements of green mine construction, explosive sources have been substituted with mechanical hammer impacts in increasing reflected in-seam wave detection. However, compared to conventional explosive sources, hammer impacts exhibit significantly lower instantaneous energy intensity and consistency. These limitations lead to reduced quality of reflected in-seam wave imaging, thus …
A Seismic Prediction Technology For Coalbed Methane Sweet Spots And Its Engineering Application In The Ordos Basin, Zhang Mengbo, Li Fei, Zhang Dong, Peng Jiankang, Cui Xiaojie, Ni Na, Long Shengfang, Tao Yu, Zhu Jun
A Seismic Prediction Technology For Coalbed Methane Sweet Spots And Its Engineering Application In The Ordos Basin, Zhang Mengbo, Li Fei, Zhang Dong, Peng Jiankang, Cui Xiaojie, Ni Na, Long Shengfang, Tao Yu, Zhu Jun
Coal Geology & Exploration
Objective Deep coalbed methane (CBM) reservoirs tend to exhibit significant tuning effects of thin interbeds, leading to challenging localization of actual coal seam boundaries, limited identification accuracy of micro-amplitude structures in the coal seam roof, and poor stability of the seismic responses of the reservoirs' gas-bearing properties. To address these challenges, this study investigated the No. 8 coal seam of the Benxi Formation in the Mizhi area, Ordos Basin. Accordingly, a method with the prediction of gas-bearing properties as the primary controlling factor was developed for the seismic prediction and comprehensive evaluation of CBM sweet spots. Methods First, the actual …
Factors Influencing The Build-Up Rate Of Small-Diameter Rotary Steerable Systems In Underground Coal Mines, Yang Dongdong, Li Quanxin, Zhang Youzhen, Chen Long, Chu Zhiwei, Jiang Bici, Wang Bo, Yan Wenchao
Factors Influencing The Build-Up Rate Of Small-Diameter Rotary Steerable Systems In Underground Coal Mines, Yang Dongdong, Li Quanxin, Zhang Youzhen, Chen Long, Chu Zhiwei, Jiang Bici, Wang Bo, Yan Wenchao
Coal Geology & Exploration
Objective Intelligent drilling represents an important part of intelligent coal mine construction. However, measurement-while-drilling (MWD) directional drilling, the core of underground intelligent drilling operations, currently suffers from several limitations, including the high dogleg severity of wellbore trajectories, low drilling efficiency, and poor hard-rock penetration. Rotary steerable system (RSS) technology has emerged as a key approach to addressing these limitations owing to its high-precision control on drilling trajectories. Methods This study systematically analyzed the factors influencing the build-up rate of small-diameter, push-the-bit RSSs using a modified 3-point circle method and the longitudinal beam bending method. Through theoretical modeling, the coupled impacts …
Machine Learning-Based Diagnosis Of Fracture-Induced Lost Circulation And Intelligent Selection Of Lost Circulation Control Fluids, Sun Huan, Zhu Mingming, Wang Jinshu, Yao Lu, Zhou Fangfang, Tan Xuebin, Sun Yan, Qu Yanping, Chen Ning
Machine Learning-Based Diagnosis Of Fracture-Induced Lost Circulation And Intelligent Selection Of Lost Circulation Control Fluids, Sun Huan, Zhu Mingming, Wang Jinshu, Yao Lu, Zhou Fangfang, Tan Xuebin, Sun Yan, Qu Yanping, Chen Ning
Coal Geology & Exploration
Objective and Method Drilling operations in the Changqing area face several challenges in lost circulation, including complex types, significantly different characteristics, and difficulty in designing plugging formulations. To address these issues, this study proposes a DSX-Hybrid coupled intelligent decision-making framework, which serves as an integrated scheme to identify lost circulation channels, perform intelligent selection of plugging formulations, and offer recommendations on construction process. In this framework, given the scarcity of labeled log data, the density-based spatial clustering of applications with noise (DBSCAN) is employed to mine latent geological characteristics of unlabeled data. Then, the self-attention convolutional neural network (SACNN) is …
Discovery And Implications For Ore Prospecting Of Gravitational Gliding Structures In The Lutang Coal-Based Graphite Mining Area, Hunan Province, China, Xiao Jincheng, Lu Jiang, Liu Zhiyu, Zhu Linying, Xiao Haibin, Li Long, Xiao Jing
Discovery And Implications For Ore Prospecting Of Gravitational Gliding Structures In The Lutang Coal-Based Graphite Mining Area, Hunan Province, China, Xiao Jincheng, Lu Jiang, Liu Zhiyu, Zhu Linying, Xiao Haibin, Li Long, Xiao Jing
Coal Geology & Exploration
Background Data from previous exploration and studies indicate that the Lutang coal-based graphite mining area in Hunan Province falls within the Lutang-Shatian synclinorium in terms of tectonic location, with coal-bearing strata dominated by the upper member of the Upper Permian Longtan Formation. Influenced by the intrusion of granites, coal seams adjacent to the Qitianling pluton on the eastern flank of the mining area have undergone contact metamorphism, forming coal-based graphite. Previous exploration results suggest that the Qitianling pluton has a maximum burial depth measured at an elevation of 0 m or less. However, with constant underground exposure in mines, previous …
Evaluation Of Deep High-Quality Reservoirs Based On The Fuzzy Analytic Hierarchy Process And The Entropy Weight Method: A Case Study Of The No. 8 Coal Seam In The East-Central Ordos Basin, Yan Ronghui, Xu Hao, Hu Jianling, Li Xiaotian, Jiao Pengshuai, Huang Daojun, Chen Shida, Wu Xiaozhuo
Evaluation Of Deep High-Quality Reservoirs Based On The Fuzzy Analytic Hierarchy Process And The Entropy Weight Method: A Case Study Of The No. 8 Coal Seam In The East-Central Ordos Basin, Yan Ronghui, Xu Hao, Hu Jianling, Li Xiaotian, Jiao Pengshuai, Huang Daojun, Chen Shida, Wu Xiaozhuo
Coal Geology & Exploration
Objective Significant breakthroughs have been achieved in the exploration and exploitation of coalbed methane (CBM) in the deep No. 8 coal seam within the east-central Ordos Basin. However, a comprehensive quantitative evaluation system at the regional scale is yet to be established for reservoirs in the No. 8 coal seam. Methods Based on logs, coal quality, and measured physical property data from over 270 wells in the east-central Ordos Basin, this study developed a comprehensive evaluation system for deep coal reservoirs using the fuzzy analytic hierarchy process combined with the entropy weight method. Specifically, the evaluation system consisted of nine …
Co2 Fracturing Stimulation Technology For Low-Yield Directional Coalbed Methane Wells And Its Applications, Zhang Junsheng, Cao Yunxing, Wang Li, Wang Zhongbin, Yang Baige, Shi Bin, Cao Yongsen, Xu Fengyi
Co2 Fracturing Stimulation Technology For Low-Yield Directional Coalbed Methane Wells And Its Applications, Zhang Junsheng, Cao Yunxing, Wang Li, Wang Zhongbin, Yang Baige, Shi Bin, Cao Yongsen, Xu Fengyi
Coal Geology & Exploration
Background In China, low-yield coalbed methane (CBM) wells represent a high proportion of approximately 57% (over 12400 wells), generally encountering challenges such as low pressure, dry reservoirs, and near-wellbore formation damage and blockage. Conventional hydraulic fracturing is prone to induce water blocking damage, while treatments such as acidification offer only limited blockage-removing radii. Therefore, existing techniques are insufficient to achieve blockage removal and permeability enhancement while avoiding reservoir damage. Exploring efficient waterless stimulation technologies suitable for these low-yield wells is of great significance for increasing CBM production and advancing the CBM industry. Methods This study investigated directional wells PXC-03 and …
Helium Origin And Primary Factors Controlling Helium Enrichment For Bauxite Gas Reservoirs In The Longdong Area, Ordos Basin, Chen Keyu, Wang Xiaofeng, Liu Wenhui, Zhang Dongdong, Li Xiaofu
Helium Origin And Primary Factors Controlling Helium Enrichment For Bauxite Gas Reservoirs In The Longdong Area, Ordos Basin, Chen Keyu, Wang Xiaofeng, Liu Wenhui, Zhang Dongdong, Li Xiaofu
Coal Geology & Exploration
Objective Significant breakthroughs have been achieved in the exploration of bauxite gas reservoirs in the Taiyuan Formation, Longdong area, Ordos Basin. Bauxites are generally considered to hold great helium generation potential due to their relatively high uranium (U) and thorium (Th) contents. However, there remains a lack of quantitative studies on their actual contribution to helium abundance in natural gas in the area. Methods To determine dominant helium source rocks and mechanisms behind helium enrichment, this study investigated the bauxite gas reservoirs within the Taiyuan Formation in the Longdong area. Through analyses of the composition, carbon isotopes, and noble gas …
Water Hazards In Thick Floor Aquicludes For Coal Mining Above Confined Aquifers In North China-Type Coalfields: Patterns, Mechanisms, And Prevention And Control, Meng Haopeng, Yin Shangxian, Lian Huiqing, Yin Huichao, Hou Enke, Zhang Yi’An, Wang Zhuo, Jin Zidong, Cai Xiangjun, Cao Min, Wang Jianguang
Water Hazards In Thick Floor Aquicludes For Coal Mining Above Confined Aquifers In North China-Type Coalfields: Patterns, Mechanisms, And Prevention And Control, Meng Haopeng, Yin Shangxian, Lian Huiqing, Yin Huichao, Hou Enke, Zhang Yi’An, Wang Zhuo, Jin Zidong, Cai Xiangjun, Cao Min, Wang Jianguang
Coal Geology & Exploration
Background Water hazards in coal seam floors represent a core challenge restricting the exploitation of deep coal resources in North China-type coalfields. As coal mining extends to greater depths, previous studies and experience exhibit limited applicability in the pattern classification, mechanism interpretation, and prevention and control of water hazards in thick floor aquicludes. Therefore, there is an urgent need to make breakthroughs and improvements in these three aspects.Methods Using several methods, including case-based induction, theoretical analysis, numerical simulation, and technical summary, this study developed a classification system based on parallel multiple criteria for floor water hazards by combining available …
Assessing Fault-Induced Floor Water Inrushes Based On Improved Water Inrush Coefficients, Jiao Bin, Tan Wenfeng, Li Hongsheng, Chen Juntao, Gao Hongbing, Zhao Zizhang, Wu Fangcan
Assessing Fault-Induced Floor Water Inrushes Based On Improved Water Inrush Coefficients, Jiao Bin, Tan Wenfeng, Li Hongsheng, Chen Juntao, Gao Hongbing, Zhao Zizhang, Wu Fangcan
Coal Geology & Exploration
Background As coal mining in mines constantly expands to greater depths, water hazards in the Ordovician limestone aquifers of coal seam floors pose a serious threat to the mining of coal seams in lower formations. Fault reactivation represents a primary factor inducing water inrushes. However, the original water inrush coefficient (T = p/M) suffers from certain limitations when used to assess the water inrushes in areas with faults. Methods Four models of floor water inrushes induced by non-penetrating faults (i.e., concealed hydraulically conductive faults, concealed isolated faults, and exposed faults) and penetrating faults were constructed, and …