Intelligent Identification Of Deep Coal Macrolithotypes Based On Weighted Ensemble In Machine Learning: A Case Study Of The Shenmu Area, Ordos Basin,
2026
Key Laboratory of Coalbed Methane Resources and Accumulation Process, Ministry of Education, China University of Mining and Technology, Xuzhou 221008, China
Intelligent Identification Of Deep Coal Macrolithotypes Based On Weighted Ensemble In Machine Learning: A Case Study Of The Shenmu Area, Ordos Basin, Yao Yuhao, Yang Zhaobiao, Huang Daojun, Wang Jianan, Dong Guodong, Chen Yilin, He Jinxian, Zhang Shang
Coal Geology & Exploration
Objective Coal macrolithotype represents a key geological property in the exploration and recovery of deep coalbed methane (CBM) resources, and its accurate identification is of great significance for selecting the optimal geological and engineering sweet-spot intervals. However, conventional coal macrolithotype identification relies heavily on core observation, suffering from prohibitively high costs since core data are extremely valuable and thus feature a small sample size. Meanwhile, conventional log-based threshold methods face challenges in effectively characterizing the complex boundaries between coal macrolithotypes.Methods This study investigated the No. 8 coal seam of the Benxi Formation, Shenmu area, eastern Ordos Basin. Based on …
A Probabilistic Lithofacies Classification Method For Deep Coal Measures,
2026
School of Earth and Environment, Anhui University of Science & Technology, Huainan 232001, China; Huaibei Mining (Group) Co., Ltd., Huaibei 235000, China
A Probabilistic Lithofacies Classification Method For Deep Coal Measures, Xu Aiguo, Zhang Pingsong, Wu Haibo, Li Shenglin
Coal Geology & Exploration
Background Deep coal measures contain multiple unconventional reservoir types, including coal, shale, and tight sandstone. Accurate lithofacies classification helps identify the resource and engineering targets of unconventional gas within these deep sequences, thus guiding category-based extraction and efficient development. However, conventional lithofacies classification methods largely rely on elastic parameters derived based on the isotropic-medium assumption or linear amplitude variation with offset (AVO) inversion while neglecting the pronounced vertical transverse isotropy (VTI) anisotropy of deep coal measures, severely limiting the lithofacies classification accuracy. Methods This study develops a probabilistic lithofacies classification method for deep coal measures. First, high-accuracy elastic parameters, including …
Multi-Round Diverting Fracturing Technology For Deep-Seated Thin Coal Seams And Its Application: A Case Study Of The G3-1 Well Group In The Yichuan Block, Ordos Basin,
2026
PetroChina Coalbed Methane Company Limited, Beijing 100028, China; China United Coalbed Methane National Engineering Research Center Co., Ltd., Beijing 100095, China
Multi-Round Diverting Fracturing Technology For Deep-Seated Thin Coal Seams And Its Application: A Case Study Of The G3-1 Well Group In The Yichuan Block, Ordos Basin, Li Shuguang, Nie Zhihong, Ji Liang, Zhou Changhui, Bai Kunsen, Huang Li, Zhen Huaibin, Xing Xuejie, Zhao Haifeng
Coal Geology & Exploration
Objective Deep coal seams in the Yichuan block of the Ordos Basin are characterized by small thicknesses, vertical multi-layer superimposition, and strong vertical and horizontal heterogeneities. When used to develop these coal seams, multi-stage horizontal well fracturing faces challenges such as uneven fracture propagation across various stages in the horizontal direction and a low production degree of multiple coal seams in the vertical direction, complicating commercial exploitation. To address these issues, this study proposes a multi-round diverting fracturing technology based on a vertical cluster well group. In this technology, vertical layered fracturing using vertical cluster wells is employed to achieve …
Scaling And Blockage In Deep Coalbed Methane Wells: Mechanisms And Countermeasures,
2026
China United Coalbed Methane National Engineering Research Center Co. Ltd., Beijing 100095, China; PetroChina Coalbed Methane Company Limited, Beijing 100028, China
Scaling And Blockage In Deep Coalbed Methane Wells: Mechanisms And Countermeasures, Zhang Lei, Chen Ming, Zhen Huaibin, Zeng Wenting, Hao Pengcheng, Hou Wei, Yin Decai, Zhang Kang, Liu Chuanqing, Tian Zhida, Liu Qihu, Wang Qian, Xiong Wei, Sun Weiwei, Xia Fei, Wang Chunyan
Coal Geology & Exploration
Background The exploitation of deep coalbed methane (CBM) is accompanied by continuous pressure drawdown. In this case, scaling and blockage are prone to occur in systems where formation water with high total dissolved solids (TDS) and high-concentration CO2 coexist. In the middle to late production stage, the blockage of both wellbore and flow pathways in reservoirs frequently leads to abrupt declines in gas production and bottomhole pressure or even induces the shutdown of natural flowing production, severely restricting the stable production of deep CBM wells. Methods This study investigated the Daning-Jixian block in the eastern Ordos Basin. Using multiple …
Technology Roadmap And Countermeasures For Lean Development Of Low-Grade Deep Coalbed Methane: A Case Study Of The Linxing-Shenfu Block, Ordos Basin,
2026
CNOOC Research Institute, Beijing 100028, China; State Key Laboratory of Offshore Oil Exploitation, Beijing 100028, China
Technology Roadmap And Countermeasures For Lean Development Of Low-Grade Deep Coalbed Methane: A Case Study Of The Linxing-Shenfu Block, Ordos Basin, Wu Guang’Ai, Xing Xuesong, Wu Jianshu, Zhu Ying, Zi Jingyu, Wang Zhi, Hou Yanan, Cheng Yuxiong, Liu Xin
Coal Geology & Exploration
Background Accelerating deep coalbed methane (CBM) exploitation is a strategic initiative for the energy security and energy mix optimization of China. The Linxing-Shenfu block in the Ordos Basin holds considerable resource potential of deep CBM. However, this block exhibits typical geological characteristics of low-grade deep CBM, including the complete absence of free gas, gas content < 14 m3/t, reservoir permeability < 0.1 × 10−3 μm2, and strong heterogeneity. These characteristics lead to low efficiency of conventional development models. Therefore, there is an urgent need to develop an efficient technical system tailored to these characteristics. Method To address the core contradiction between reservoir …
Numerical Simulation Of Stress Shadow Effect And Cluster Spacing Optimization For Multi-Cluster Fracturing In Deep Coalbed Methane Horizontal Wells,
2026
China United Coalbed Methane Co., Ltd., Beijing 100015, China
Numerical Simulation Of Stress Shadow Effect And Cluster Spacing Optimization For Multi-Cluster Fracturing In Deep Coalbed Methane Horizontal Wells, Guo Guangshan, Deng Zhiyu, Sun Le, Pu Yifan, Wu Jian, Tao Shu, Chen Shaojuan, Chen Shida
Coal Geology & Exploration
Purpose Multi-stage, multi-cluster fracturing in horizontal wells represents a key technique for deep coalbed methane (CBM) recovery and the sustainable development of the industry. However, during multi-cluster fracturing in deep CBM horizontal wells, the stress shadow effect tends to induce non-uniform fracture propagation and a limited stimulated reservoir volume (SRV). Methods To address these challenges. this study established a two-dimensional (2D) numerical model for multi-cluster hydraulic fracturing in horizontal wells using the finite element method. Then, it systematically analyzed the impacts of in situ stress and cluster spacing on both the stress shadow effect and the competitive propagation of hydraulic …
Fracturing With Three-Dimensional Full-Scale Fracture Network Propping For Deep Coalbed Methane Reservoirs: A Novel Ceramic Micro-Proppant And Its Verification Through Numerical Simulations,
2026
School of Petroleum Engineering, Yangtze University, Wuhan 430100, China; Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering, Wuhan 430100, China
Fracturing With Three-Dimensional Full-Scale Fracture Network Propping For Deep Coalbed Methane Reservoirs: A Novel Ceramic Micro-Proppant And Its Verification Through Numerical Simulations, Li Xiang, Xu Jun, Li Ting, Zhang Xiaoyu, Yang Bo
Coal Geology & Exploration
Objective and Methods Conventional fracturing struggles to achieve the long-term effective propping of complex fracture networks during the development of deep coalbed methane (CBM) reservoirs. To address this challenge, this study developed a novel ceramic micro-proppant suitable for the volumetric microfracture propping and, through numerical simulations, verified its performance when it was applied to reservoir stimulation in conjunction with the technology of fracturing with three-dimensional full-scale fracture network propping. First, a novel ceramic micro-proppant with a core-shell structure was designed according to the requirements of microfracture propping. Its key properties, including compressive strength, settling behavior, hydraulic conductivity, and stability, were …
A Spatiotemporal Surrogate Model And Multi-Objective Optimization For Multi-Well Coalbed Methane Production,
2026
Gas Field Company, Shaanxi Yanchang Petroleum (Group) Co., Ltd., Yan’an 716000, China
A Spatiotemporal Surrogate Model And Multi-Objective Optimization For Multi-Well Coalbed Methane Production, Qin Yuancheng, Wang Mengyi, Wang Yanfeng, Li Yuan, He Bo, Fang Junling, Duan Qingshan, Liu Chen
Coal Geology & Exploration
Objective and Methods In the full-lifecycle optimization of multi-well and long-term coalbed methane (CBM) production, conventional numerical simulation methods face challenges including extremely high computational costs and difficult multi-objective trade-offs. To address these issues, this study proposed a spatiotemporal surrogate model for multi-objective optimization of CBM production. First, a heterogeneous reservoir model involving 17 production wells was constructed based on high-fidelity numerical simulation, and a sample dataset was created by applying random perturbations to the baseline production scheme. Second, a hybrid surrogate model integrating a convolutional neural network (CNN) and a Transformer decoder was established. The CNN was utilized for …
Numerical Simulation And Process Optimization Of Multi-Round Fracturing In Deep Coalbed Methane Wells In The Linxing-Shenfu Block,
2026
CNOOC EnerTech-Drilling & Production Co., Tianjin 300452, China; College of Petroleum Engineering, China University of Petroleum, Beijing, 102249
Numerical Simulation And Process Optimization Of Multi-Round Fracturing In Deep Coalbed Methane Wells In The Linxing-Shenfu Block, Li Yu, Zhang Liang, Li Yunyun, An Qi, Feng Xuesong, Lan Tian, Yu Ji, Liu Xin
Coal Geology & Exploration
Objective Deep coalbed methane (CBM) holds considerable resource potential. However, deep CBM reservoirs exhibit high in-situ stresses, while deep coals feature strong plasticity and heterogeneity. These characteristics render it challenging to generate complex fracture networks through conventional fracturing, thus restricting the large-scale commercial development of deep CBM resources. Multi-round fracturing enables fracture initiation, propagation, and propping through sequential cycles of fracturing fluid injection, pump shut-in, and injection. By constantly changing near-wellbore stress fields, this technique facilitates the formation of complex fracture networks and ensures uniform reservoir stimulation. Method Using the finite-discrete element method (FDEM), this study established a numerical model …
Comparison Of Gravity Separation And Flotation For Pyrite Recovery From Tailings,
2026
Istanbul Technical University, Mineral Processing Engineering Department, Maslak, Istanbul, Türkiye
Comparison Of Gravity Separation And Flotation For Pyrite Recovery From Tailings, Gülay Bulut, Gönül Göksu Gökçe, Dilruba Karamanlı, Oğuzhan Mert Gürkan, Ergin Sarp Zenzirci, Binnur Kırım, Alim Gül
Journal of Sustainable Mining
Tailings generated during the production of lead, zinc, and copper concentrates contain significant amounts of sulfide minerals, particularly pyrite. Pyrite, which remains in tailings after the recovery of other metals, is one of the main contributors to acid mine drainage (AMD). Therefore, recovering pyrite from tailings is environmentally and economically an important issue. In this study, pyrite recovery from tailings was investigated using flotation and gravity separation methods. Mineralogical characterization and liberation analyses were conducted by Mineral Liberation Analysis (MLA), indicating that pyrite is the major sulfide mineral with over 76% liberation degree even in the coarsest fractions. Flotation tests …
Hydrothermal Alteration Mapping Of The Northern Coongan Greenstone Belt Using Remote Sensing Imagery,
2026
Ministry of Mines, Mineral Industry Development Institute, Ethiopia
Hydrothermal Alteration Mapping Of The Northern Coongan Greenstone Belt Using Remote Sensing Imagery, Meaza Bogale, Elias Woldeyohanis
Journal of Sustainable Mining
Archean greenstone belts are well known for their ore deposits, diverse lithostratigraphy, and well-preserved evidence from the early Earth. The Northern Coongan Greenstone Belt is an Archean greenstone belt that is part of the Eastern Pilbara Craton of Western Australia. The rock units of this area have the potential to be sources of valuable mineral deposits, which could be economically beneficial for extraction. Studies have been conducted in the northern Coongan greenstone belt, mostly using geological field methods and geophysical interpretations, excluding remote sensing methods for mapping mineral indices. Therefore, this study aims at providing surface mineral distribution maps and …
The Evolution Characteristics Of Gas Pressure Around Coal Seam Directional Long Extraction Boreholes With Nonlinear Extraction Negative Pressure,
2026
Wuhan Institute of Technology, School of Resources and Safety Engineering, Hubei Province, Wuhan, 430205, China
The Evolution Characteristics Of Gas Pressure Around Coal Seam Directional Long Extraction Boreholes With Nonlinear Extraction Negative Pressure, Zhang Qi, Jia Jinlong, Li Zhiguo, Zhang Longgang, Qin Zhengyuan, Zhang Weizhong, Li Jin
Journal of Sustainable Mining
Nonlinear pressure of coal seam gas in the directional borehole and surrounding areas affects extraction efficiency. A multi-field coupling numerical model, including gas desorption, diffusion, fracture seepage, and borehole extraction, is developed for the No. 3 coal seam of the GJH mine. Using the numerical simulation method of control variables, extraction was developed to investigate the nonlinear evolution of axial pressure gradients in directional long borehole and the spatiotemporal response characteristics of gas pressure. Results show that coal seam seepage pressure exhibits a nonlinear radial gradient attenuation around the borehole, evolving through rapid pressure change, stabilization, and slow adjustment. The …
Monitoring System In The Georeactor Area During The Underground Coal Gasification Process,
2026
Central Mining Institute – National Reserach Institute, Department of Energy Saving and Air Protection,, Poland
Monitoring System In The Georeactor Area During The Underground Coal Gasification Process, Aleksandra Tokarz, Jacek Grabowski, Krzysztof Korczak
Journal of Sustainable Mining
Safety control of the underground coal gasification (UCG) process involves ensuring that the process runs smoothly, monitoring changes occurring on the surface and in the rock mass, and counteracting the negative environmental impact of the process. The article presents the application of a monitoring system implemented in Poland, both in pilot tests conducted in shallow coal seams at the Barbara Experimental Mine and in deep coal seams at the Wieczorek mine, where a full-scale gasification process was tested. The analysis of the monitoring results carried out during the gasification experiment in an operating mine allowed for the identification of key …
Microwave Thermal Pre-Treatment To Improve Nickel Extraction From Lateritic Ore,
2026
Universidad Pedagógica y Tecnológica de Colombia. Facultad de Ingeniería. Escuela de Ingeniería Metalúrgica. Avenida Central del Norte, Km 4, Edif. de Ingeniería, Tunja, 150003, Colombia
Microwave Thermal Pre-Treatment To Improve Nickel Extraction From Lateritic Ore, Johana Borda, Daniel Sosa, Robinson Torres
Journal of Sustainable Mining
Two heat treatment processes for a nickeliferous laterite sample are presented, one by the conventional muffle route and the other by microwave. The heating was carried out in order to improve the dissolution of nickel in an acid medium. The study describes the changes observed in the mineral for the increase in temperature as a consequence of radiation in the microwave and in the muffle. The changes in the mineral crystalline phases were analyzed by X-ray diffraction. The leaching media consisted of a 1 M sulfuric acid solution at ambient conditions for 7 h. The interaction between the reagent and …
Table Of Contents,
2026
China Coal Technology and Engineering Group (CCTEG)
Resilience-Oriented Geological Safeguards For Damage Mitigation In Coal Resource Exploitation,
2026
China United Coalbed Methane National Engineering Research Center Co., Ltd., Beijing 100095, China
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 …
Mechanisms And Implications Of The Novel Cast Model Of Coal Graphitization,
2026
College of Geoscience and Surveying Engineering, China University of Mining and Technology (Beijing), Beijing 100083, China
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 …
Spatial Topological Configurations Of Cleats And Geometrical Quantitative Characterization Of Matrix Blocks In Deep Coal Seams,
2026
Key Laboratory of Coalbed Methane Resources & Reservoir Formation Process, Ministry of Education, China University of Mining and Technology, Xuzhou 221008, China;School of Resources and Geosciences, China University of Mining and Technology, Xuzhou 221116, China
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,
2026
College of Energy Resources, Chengdu University of Technology, Chengdu 610051, China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu 610051, China
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,
2026
China United Coalbed Methane National Engineering Research Center Co., Ltd., Beijing 100095, China;PetroChina Coalbed Methane Co., Ltd., Beijing 100028, China;Key Laboratory of Coalbed Methane Resources and Reservoir Formation Process, Ministry of Education, China University of Mining and Technology, Xuzhou 221008, China
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 …
