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Full-Text Articles in Earth Sciences

Did Seismic Events Trigger The Growth Of Aragonitic Speleothems In Mawmluh Cave, North-East India?, Dildi Dildi, Dana Riechelmann Dr., Michael Weber Dr., Anne Jantschke Dr., Regina Mertz-Kraus Dr., Denis Scholz Dr. Oct 2026

Did Seismic Events Trigger The Growth Of Aragonitic Speleothems In Mawmluh Cave, North-East India?, Dildi Dildi, Dana Riechelmann Dr., Michael Weber Dr., Anne Jantschke Dr., Regina Mertz-Kraus Dr., Denis Scholz Dr.

International Journal of Speleology

Mawmluh Cave, north-east India, is located in a seismically very active region within the Himalayas with frequent earthquakes of varying magnitude. So far, speleothems from the cave have mainly been used to reconstruct past monsoon variability. The potential effect of seismic events on speleothem formation in Mawmluh Cave, however, has not been studied in detail yet. We investigated three stalagmites from Mawmluh Cave, each predominantly consisting of calcite overlain by substantially younger aragonite at the top (i.e., an aragonite ‘cap’). 230Th/U-dating shows that the initiation of aragonite growth occurred between 1859 and 1950 CE in agreement with previous studies. The …

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Beyond The Poster Session: Turning A Scientific Poster Into A Publishable Manuscript, Scott R. Beason Oct 2026

Beyond The Poster Session: Turning A Scientific Poster Into A Publishable Manuscript, Scott R. Beason

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Scientific posters are often treated as the final product of an undergraduate research project. After months of fieldwork, laboratory analysis, data processing, and interpretation, a student prepares a poster, presents the work at a departmental symposium or professional meeting, rolls up the poster, and moves on to the next stage of their career. The research, however, does not necessarily need to end with the poster session. A well-developed scientific poster already contains many of the fundamental elements of a scientific manuscript: a research question, scientific context, methods, results, figures, interpretation, discussion, and conclusions. Converting a poster into a manuscript therefore …

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In Memoriam: Dr. Don C. Steinker (1936-2026), Paleobiologist, Teacher, Editor, And Mentor, Margaret M. Yacobucci, Susan T. Goldstein, Ronald E. Martin Oct 2026

In Memoriam: Dr. Don C. Steinker (1936-2026), Paleobiologist, Teacher, Editor, And Mentor, Margaret M. Yacobucci, Susan T. Goldstein, Ronald E. Martin

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Dr. Don C. Steinker, Professor Emeritus of Geology and Paleobiology, died at the age of 89 in Bowling Green, Ohio, on February 5, 2026. During his remarkable 43-year career at Bowling Green State University (BGSU), Don played a pivotal role in developing the Paleobiology specialization within the Geology undergraduate degree program, mentored generations of students, and served as advisor for the Beta Upsilon chapter of Sigma Gamma Epsilon (SGE) from 1969 until his retirement in 2010. In this brief memorial, we will highlight some of Don’s most important contributions to BGSU’s geology program, the field of foraminiferal paleobiology, geoscience education, …

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A Tribute To Frank Delno Holland, Jr. (1924-2023), Sigma Gamma Epsilon National President (1970-1975), Paleontologist, And Friend, John M. Erickson Oct 2026

A Tribute To Frank Delno Holland, Jr. (1924-2023), Sigma Gamma Epsilon National President (1970-1975), Paleontologist, And Friend, John M. Erickson

The Compass: Earth Science Journal of Sigma Gamma Epsilon

Frank Delno Holland, Jr., was born in Leavenworth, Kansas, on March 6, 1924. All family and friends, including his students and professional acquaintances, knew him as Bud. His parents were Frank D. Holland and Francys Bell Holland. His paternal grandparents, O.B. and Laura Holland were North Dakotans who had homesteaded in Sargent County during the 1880s, but had relocated to Kansas in 1903. Bud had a rural upbringing on the outskirts of Leavenworth, graduating in 1942 from Leavenworth High school. It seemed natural that he would follow in his father’s footsteps by attending the University of Kansas (KU) so Bud …

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The Compass - Volume 95 Issue 2 - Complete Issue, Scott R. Beason Oct 2026

The Compass - Volume 95 Issue 2 - Complete Issue, Scott R. Beason

The Compass: Earth Science Journal of Sigma Gamma Epsilon

No abstract provided.

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Clustering Of Potable Water Sources In Rural Oyo State, Nigeria: Implications For Equitable Distribution And Sustainability, Adesola Adediran, Ibrahim O. Raufu Sep 2026

Clustering Of Potable Water Sources In Rural Oyo State, Nigeria: Implications For Equitable Distribution And Sustainability, Adesola Adediran, Ibrahim O. Raufu

Tanzania Journal of Science

Adequate and equitable access to potable water remains a major challenge in rural communities of Oyo State, Nigeria, with uncoordinated provision leading to widespread shortages. This study employs geospatial techniques to assess the spatial distribution of water supply sources across five purposively selected rural communities in Olorunsogo Local Government Area (OLGA). Geographic coordinates of boreholes, hand-dug wells, and other potable water sources were collected using a handheld Garmin GPS 76S device. Spatial analysis was conducted using ArcGIS, and Nearest Neighbour Analysis (NNA) was applied to evaluate the pattern of distribution. Results indicate a strong tendency toward clustering, with a Nearest …

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Distribution Of Diagenetic Alterations In Lower Cretaceous Strata Of The Tanzanian Coastal Sedimentary Basin, Justina James Saroni Sep 2026

Distribution Of Diagenetic Alterations In Lower Cretaceous Strata Of The Tanzanian Coastal Sedimentary Basin, Justina James Saroni

Tanzania Journal of Science

The Lower Cretaceous sedimentary rocks of the Coastal Sedimentary Basin of Tanzania crop out in the Wami and Mandawa basins and are stratigraphically similar to the reservoir rocks hosting gas at Songo Songo. This study examines the relationship between facies and diagenetic processes in outcrops from the study area. Outcrop description and petrographic analysis by using optical and scanning electron microscopy (SEM) were used to identify facies and diagenetic alterations. Sixteen facies were identified, including siliciclastic facies: conglomerate (Gm), sandstones (St, Sp, Sm, Sh, Sr), siltstone and mudstone (Fm, Fl); and carbonate facies are packstone (Lsp, Lspc, Lspg, Lspo), grainstone …

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Table Of Contents, The Editors Sep 2026

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

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Unique Connotation Of Geological-Engineering Dual Sweet Spot Evaluation For Effective Coalbed Methane Exploitation, Luo Pingya, Zhu Suyang Sep 2026

Unique Connotation Of Geological-Engineering Dual Sweet Spot Evaluation For Effective Coalbed Methane Exploitation, Luo Pingya, Zhu Suyang

Coal Geology & Exploration

Objective In China, the exploitation of deep and shallow coalbed methane (CBM) still relies on the evaluation approach oriented to the geological-engineering dual sweet spots of unconventional hydrocarbons. However, exemplary CBM production technologies delivered unsatisfactory performance in other blocks and failed to find wide application even in zones with overlapping geological and engineering sweet spots. This issue represents the principal theoretical and technical challenge confronting the comprehensive development of the CBM industry in China. Methods This study aims to elucidate the causes of this issue and provide corresponding solutions, as well as clarifying the conditions for the effective linkage between …

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Exploration And Prospects Of Engineering Technologies For Deep Coal Seam Development Based On The Well Factory Mode, Gao Deli, Dong Xuelin, Bi Yansen Sep 2026

Exploration And Prospects Of Engineering Technologies For Deep Coal Seam Development Based On The Well Factory Mode, Gao Deli, Dong Xuelin, Bi Yansen

Coal Geology & Exploration

Background Given China's energy and mineral resource endowment, the efficient and green development and utilization of deep coal resources are expected to become a significant strategic option for facilitating the country's green energy transition and achieving its goals of peak carbon dioxide emissions and carbon neutrality. This significant demand may be satisfied through development using a structurally complex well factory mode. Method This study introduces the basic concept of a three-dimensional, multi-functional, and precisely controllable underground structurally complex well factory, designed for the efficient and green development of unconventional energy and mineral resources. It then discusses the well factory engineering …

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Differential Accumulation Of Coalbed Methane In Medium- To Low-Rank Coal Seams In A Strongly Compressional Tectonic Setting In The Tarim Basin, Liu Honglin, Wang Hongyan, Wang Haichao, Deng Ze Sep 2026

Differential Accumulation Of Coalbed Methane In Medium- To Low-Rank Coal Seams In A Strongly Compressional Tectonic Setting In The Tarim Basin, Liu Honglin, Wang Hongyan, Wang Haichao, Deng Ze

Coal Geology & Exploration

Background The Tarim Basin contains abundant coal and coalbed methane (CBM) resources. However, the geological accumulation patterns of CBM in the basin remain poorly understood. This leads to a relative lack of targeted technologies for the exploration and development of both deep coal reservoirs and steeply dipping coal seams, further rendering it challenging to achieve breakthroughs in CBM development in the basin. Methods Based on test data from 92 coal samples, data on the drilling and production tests of more than 10 exploration wells, and 3D seismic interpretation results, this study systematically investigated the distribution of coal-bearing strata, as well …

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Variable-Temperature And Variable-Pressure Adsorption Characteristics Of Deep Coalbed Methane And Their Implications, Jiang Wenping, Sun Siqing, Jin Xianglan, Tian Bofan, Tian Xinjuan Sep 2026

Variable-Temperature And Variable-Pressure Adsorption Characteristics Of Deep Coalbed Methane And Their Implications, Jiang Wenping, Sun Siqing, Jin Xianglan, Tian Bofan, Tian Xinjuan

Coal Geology & Exploration

Background Investigating the adsorption characteristics of coalbed methane (CBM) helps bridge key geological information concerning deep CBM, including occurrence state, free gas proportion, and gas-bearing properties, with the gas production potential and commercial exploitation of CBM wells. Such investigation represents a key component of the evaluation, exploration, and exploitation of CBM reservoirs. Methods Using deep coal samples collected from three representative regions, this study designed high-temperature and high-pressure methane isothermal adsorption experiments, together with variable-temperature and variable-pressure methane adsorption experiments, using nuclear magnetic resonance (NMR). The adsorption characteristics of the coal samples derived using the different experimental methods were subsequently …

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Occurrence Pattern Of Adsorbed And Free Gas In Deep Coal Seams Under The Control Of Pore Structure: A Case Study Of The No. 8 Coal Seam In The Daning-Jixian Block Along The Eastern Margin Of The Ordos Basin, Bian Liheng, Shen Jian, Shi Rui, Zhang Wei, Ma Zhuang, Liang Xuemin, Dong Jiying, Zhu Peipei, Ma Tianyu Sep 2026

Occurrence Pattern Of Adsorbed And Free Gas In Deep Coal Seams Under The Control Of Pore Structure: A Case Study Of The No. 8 Coal Seam In The Daning-Jixian Block Along The Eastern Margin Of The Ordos Basin, Bian Liheng, Shen Jian, Shi Rui, Zhang Wei, Ma Zhuang, Liang Xuemin, Dong Jiying, Zhu Peipei, Ma Tianyu

Coal Geology & Exploration

Background Deep coalbed methane (CBM) holds an important strategic position in China's unconventional natural gas system. However, concerning deep CBM occurrence, there remains a lack of systematic quantitative understanding of the underlying mechanisms and the controlling effects of pore structure. Methods This study investigated high-rank coal samples collected at a burial depth of approximately 2000 m from the No. 8 coal seam in the Daning-Jixian block along the eastern margin of the Ordos Basin. Using multiscale pore characterization techniques, including low-temperature liquid nitrogen adsorption, high-pressure mercury injection, and low-temperature CO2 adsorption, the full-scale pore size distribution of the coal …

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Controlling Effects Of Ash Yield On The Adsorption-Desorption Behavior And Production Potential Of Methane In Deep Coal Reservoirs, Huang Daojun, Liu Xinshe, Chen Shida, Sun Wen, Jiao Pengshuai, Wang Huaichang Sep 2026

Controlling Effects Of Ash Yield On The Adsorption-Desorption Behavior And Production Potential Of Methane In Deep Coal Reservoirs, Huang Daojun, Liu Xinshe, Chen Shida, Sun Wen, Jiao Pengshuai, Wang Huaichang

Coal Geology & Exploration

Objective The lithotype and quality characteristics of coals significantly affect the reservoir permeability and production potential of coalbed methane (CBM). However, there remains a lack of clear understanding of the controlling effects of ash yield on the gas-bearing properties and methane adsorption-desorption behavior of coal seams under comparable thermal maturity. Focusing on coal samples obtained through continuous sealed coring from the No. 8 coal seam in well M172 in the east-central part of the Ordos Basin, this study aims to clarify the impacts of ash yield on the pore structure, adsorption capacity, desorption process, and resource recoverability. This effort is …

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Components And Isotope Fractionation Of Deep Coalbed Methane And Their Geological Implications In The Daning-Jixian Block, Ordos Basin, Wang Chengwang, Zhang Yun, Wang Hongna, Chen Yiyu, Chen Gaojie, Wang Jun, Liu Lingqi, Li Panxue, He Hongcheng, Li Wenbiao Sep 2026

Components And Isotope Fractionation Of Deep Coalbed Methane And Their Geological Implications In The Daning-Jixian Block, Ordos Basin, Wang Chengwang, Zhang Yun, Wang Hongna, Chen Yiyu, Chen Gaojie, Wang Jun, Liu Lingqi, Li Panxue, He Hongcheng, Li Wenbiao

Coal Geology & Exploration

Objective The components of deep coalbed methane (CBM), along with its isotopic composition and fractionation patterns, hold great significance for revealing the genetic types, occurrence characteristics, flow, and production patterns of CBM. Methods This study investigated the Shanxi and Benxi formations in the Daning-Jixian block, Ordos Basin. A range of analyses and tests were conducted, including field CBM desorption experiments on coal samples from the deep parts of both formations, continuous monitoring of wellhead gas from two production wells, physical property tests on the samples, organic petrological experiments, and geochemical analysis. Furthermore, this study analyzed the components and isotopes of …

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Investigating The Mechanisms Controlling Gas Flow In Coal Reservoirs Based On Multi-Scale Digital Rocks, Han Lei, Huang Dongxiang, Zhang Xiaodong, Shen Jian, Zhang Shuo, Ni Xiaoming, Liu Xiao Sep 2026

Investigating The Mechanisms Controlling Gas Flow In Coal Reservoirs Based On Multi-Scale Digital Rocks, Han Lei, Huang Dongxiang, Zhang Xiaodong, Shen Jian, Zhang Shuo, Ni Xiaoming, Liu Xiao

Coal Geology & Exploration

Background Deep coal reservoirs exhibit highly heterogeneous pore-fracture structures. However, limited by a single imaging resolution, conventional digital rock techniques struggle to characterize complex pore-fracture networks across multiple scales. This poses significant scientific challenges for the fine-scale characterization of deep coal reservoirs and the investigation of their seepage mechanisms. Methods This study investigated deep coalbed methane (CBM) reservoirs in the north-central Qinshui Basin. The pore-fracture structures of coal samples were characterized by integrating X-ray computed tomography (CT), mercury injection capillary pressure (MICP), and scanning electron microscopy (SEM). Digital rock models incorporating multi-scale pores and fractures were then constructed by integrating …

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Investigating The Characteristics Of Ch4 Adsorption In Coal Reservoirs Based On Interpretable Machine Learning, Chen Ruibin, Zhou Sandong, Zhang Weixin, Yan Detian, Wang Hua Sep 2026

Investigating The Characteristics Of Ch4 Adsorption In Coal Reservoirs Based On Interpretable Machine Learning, Chen Ruibin, Zhou Sandong, Zhang Weixin, Yan Detian, Wang Hua

Coal Geology & Exploration

Objective Accurately predicting methane (CH4) adsorption capacity in coal reservoirs is critical to the efficient exploration and exploitation of coalbed methane (CBM). Existing studies largely rely on experimental data from a small number of samples and theoretical adsorption models such as Langmuir. However, these studies exhibit time-consuming and laborious processes, as well as conclusions with limited generalizability, posing challenges to their widespread applications across different basins. Methods Based on 1150 sets of experimental data on CH4 adsorption in coals, this study investigated five machine learning models, namely artificial neural network (ANN), support vector machine (SVM), K-nearest neighbor …

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Mechanical Anisotropy And Depth Effects Of Deep Coal Seams, Mei Xiaofan, Wang Cong, Wang Kaifeng, Tang Shuheng, Zhang Songhang, Xi Zhaodong Sep 2026

Mechanical Anisotropy And Depth Effects Of Deep Coal Seams, Mei Xiaofan, Wang Cong, Wang Kaifeng, Tang Shuheng, Zhang Songhang, Xi Zhaodong

Coal Geology & Exploration

Objective The mechanical properties of coal seams determine the stability, fracability, and fracturing performance of deep coal reservoirs. Since the in situ stress applied to coal increases with burial depth, deep coal differs from its shallow counterpart in damage behavior, key mechanical parameters, and failure mechanism. Furthermore, deep coal exhibits pronounced mechanical anisotropy.Methods Focusing on the No. 9 coal seam in the Linxian area along the eastern margin of the Ordos Basin, this study carried out triaxial compression tests at 60℃ under different confining pressures to determine the mechanical anisotropy of deep coal. By comparing the full stress-strain curves, …

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An Improved Brittleness Characterization Method For Deep Coalbed Methane Reservoirs And Its Application To Well Logs, Huang An’Er, Gong Fei, Peng Suping, Zou Guangui, Zhang Zhaoji, Wu Yiquan, Rong Zhihong, Li Qingrun Sep 2026

An Improved Brittleness Characterization Method For Deep Coalbed Methane Reservoirs And Its Application To Well Logs, Huang An’Er, Gong Fei, Peng Suping, Zou Guangui, Zhang Zhaoji, Wu Yiquan, Rong Zhihong, Li Qingrun

Coal Geology & Exploration

Background Deep coalbed methane (CBM) reservoirs are characterized by high pressure, low porosity, and low permeability. Therefore, large-scale volume fracturing is required for their commercial development. As an important engineering sweet spot parameter for selecting optimal fracturing targets, the brittleness index can reflect the difficulty in generating complex fracture networks during fracturing. However, existing brittleness characterization methods are largely applicable to strata with high brittle mineral content, such as shales and sandstones, while methods for characterizing the brittleness of deep CBM reservoirs with high organic matter content and low brittle mineral content are lacking. Methods Rock physics experiments on 20 …

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A Fault Identification Method For Deep Coalbed Methane Reservoirs Based On An Improved Transunet, Gao Congshun, Wu Haibo, Liu Lei, Wang Zijian, Huang Xuanyu, Jia Lilan, Xu Aiguo Sep 2026

A Fault Identification Method For Deep Coalbed Methane Reservoirs Based On An Improved Transunet, Gao Congshun, Wu Haibo, Liu Lei, Wang Zijian, Huang Xuanyu, Jia Lilan, Xu Aiguo

Coal Geology & Exploration

Objective Small-scale faults in deep coalbed methane (CBM) reservoirs significantly affect CBM enrichment and the deployment of development wells. However, deep seismic data tend to suffer from low signal-to-noise ratios (SNRs) and poor continuity of reflection events, while conventional methods are likely to miss small-scale faults. To address these limitations, this study proposes a fault identification method based on an improved TransUNet. Methods The proposed method is developed based on the R50-ViT-B_16 TransUNet architecture. A coordinate attention (CA) module is introduced before the skip connections enter the decoder to enhance the feature representation of the locations and directional continuity of …

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Petrophysical Model-Driven Seismic Inversion For Physical Property Parameters Of Deep Coalbed Methane Reservoirs, Chen Yang, Guo Qiang, Ba Jing Sep 2026

Petrophysical Model-Driven Seismic Inversion For Physical Property Parameters Of Deep Coalbed Methane Reservoirs, Chen Yang, Guo Qiang, Ba Jing

Coal Geology & Exploration

Objective Deep coalbed methane (CBM) reservoirs typically exhibit complex pore-fracture structures, as well as strong nonlinear and non-unique corresponding relationships between elastic and physical property parameters. In this context, this study develops a seismic petrophysical inversion method that accounts for pore structure variations. Methods This study investigated deep CBM reservoirs along the eastern margin of the Ordos Basin. First, a petrophysical model based on variable pore aspect ratios was established, and the corresponding linearized forward operator was derived. Then, the pore aspect ratios were estimated using near-borehole log data. Meanwhile, the multimodal prior distributions of reservoir physical property parameters were …

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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 Sep 2026

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 …

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A Probabilistic Lithofacies Classification Method For Deep Coal Measures, Xu Aiguo, Zhang Pingsong, Wu Haibo, Li Shenglin Sep 2026

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 …

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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 Sep 2026

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 …

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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 Sep 2026

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 …

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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 Sep 2026

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 …

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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 Sep 2026

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 …

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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 Sep 2026

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 …

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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 Sep 2026

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 …

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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 Sep 2026

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 …

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