Natural Resources Research最新文献

{"title":"Numerical Modeling of Permeability Sensitivities Based on Characteristics of Heterogeneous Coal Structure Reservoirs","authors":"Rui Wang, Kun Zhang, Guofu Li, Liangwei Xu","doi":"10.1007/s11053-025-10489-8","DOIUrl":"https://doi.org/10.1007/s11053-025-10489-8","url":null,"abstract":"<p>Reservoir sensitivities play a crucial role in affecting the production efficiency of coalbed methane, relating to adsorption/desorption dynamics, pore–fracture interactions, and pressure characteristics within the reservoir. This study examined changes in permeability sensitivity within a heterogeneous coal structure reservoir by continuously sampling seven coal sections from roof to floor. The samples underwent low-temperature N₂ and isothermal adsorption analysis of CH₄, as well as microscopic observation experiments. Based on the results, a permeability sensitivity evaluation model was proposed. The study revealed that the No. 3 coal seam in the area maintained its integrity, primarily consisting of intact and cataclastic coal structures. The isothermal adsorption experiments and N₂ adsorption analysis indicated that the highest Langmuir <i>V</i>_<i>L</i> (24.03 cm³/g), specific surface area, and mesopore volumes were found in the middle part of the coal seam. Cataclastic coal, influenced by tectonic deformations, formed more micropores than the intact coal. The coal seam exhibited complex vertical variations in macroscopic and microscopic fractures, including differences in aperture, frequency, spacing, connectivity, and mineralization. The model also simulated changes in permeability sensitivities, considering effective stress and volumetric changes in the coal matrix during gas desorption. It was found that the middle part of the coal seam exhibited the most significant stress sensitivity and the highest permeability loss ratio. The study concludes that attention should be focused on the middle part of the coal seam in the Gaohe and adjacent coal fields for the stimulation of the coalbed methane (CBM) reservoir and prevention of gas outburst. This research is instrumental in determining CBM production design and evaluating development risks.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"20 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143745699","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Spatial–Temporal Response Law and Main Controlling Factors of Temperature During Coal-and-Gas Outburst","authors":"Chaolin Zhang, Qiaozhen Jiang, Xiaofei Liu, Enyuan Wang, Jiabo Geng","doi":"10.1007/s11053-025-10482-1","DOIUrl":"https://doi.org/10.1007/s11053-025-10482-1","url":null,"abstract":"<p>One of the most common catastrophes that occur during the coal mining process is the coal-and-gas outburst. However, due to the complexity of this phenomenon, there are many variables affect it, and the degree of synergistic coupling of various factors is deep, and so the mechanism of its occurrence cannot be fully grasped so far. Existing research mainly focused on the temperature variation law of coal-and-gas outburst under a single influencing factor, which is limited in understanding of the temperature evolution law in the outburst process under the coupling of multiple influencing factors. In this study, the temperature change of the whole process of the outburst was monitored by carrying out physical simulation experiments under different conditions (gas pressure, in-situ stress and permeability). According to the experimental results and theoretical analysis, it was found that the temperature of the coal seam and the roadway following an outburst follows an evolutionary pattern of first rapid decrease, then rapid rise, and finally slow change in time. Then, the weights of three influencing factors were determined by the analytic hierarchy process—criteria importance through inter-criteria correlation (AHP–CRITIC) mixed weighting method, and it was concluded that the temperature evolution of coal-and-gas outburst was mainly controlled by gas pressure. Finally, further fitting was conducted to obtain the exponential variation of temperature drop peak and outburst propagation distance under various conditions of gas pressure, and the physical meanings of different fitting parameters were discussed. On this basis, the abnormal change of coal seam temperature can be detected, and the roadway temperature can be predicted, thereby studying the influence range of the two-phase flow and further evaluating the disaster-causing effect, and providing a new idea for the prediction and prevention of coal-and-gas outburst disaster.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"49 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143745700","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Uncertainty Quantification of Microblock-Based Resource Models and Sequencing of Sampling","authors":"Glen T. Nwaila, Emmanuel John M. Carranza","doi":"10.1007/s11053-025-10485-y","DOIUrl":"https://doi.org/10.1007/s11053-025-10485-y","url":null,"abstract":"<p>Spatial models are fundamental across the mineral value chain, forming the basis for exploration and extraction. Geodata science and increasingly bigger data permit alternatives to traditional mineral resource estimation methods, particularly in spatial data interpolation. Interpolation has been formulated as a machine learning (ML) task, providing new capabilities, such as automated deployment and remote real-time monitoring. However, a significant gap exists regarding how uncertainty propagates through ML workflows. This paper introduces an uncertainty propagation method to a ML-based interpolation method called microblocking that propagates epistemic uncertainty. Our method adheres to the data science framework and is fully ML-based. Epistemic uncertainty is the dominant uncertainty in geosciences, because data sparsity is created by both complex dynamics of physical systems and sampling limitations. Our uncertainty estimates are block-specific and can guide sampling and other activities. Biasing sampling toward blocks with high economic potential and high uncertainty enables the most cost-effective sequencing of sampling. A rapid, ML-based uncertainty quantification method provides a modern data-driven (feedback-based) framework to extraction guidance, built on big data, geodata science, and real-time mineral resource modeling. We compare our method with typical kriging uncertainty estimates and demonstrates that our results are more block-specific and broader in scope (more comprehensive). In an industry where financial stakes are significant, a thorough understanding of uncertainty can improve investor confidence. The method not only improves scientific rigor, but is also engineered to fit increasingly bigger data across the mineral value chain, and caters to the conservative nature of the mineral industry, where method validation occurs at a slower pace.</p><h3 data-test=\"abstract-sub-heading\">Graphical Abstract</h3>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"58 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143734197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mineral Prospectivity Modeling of Graphite Deposits and Occurrences in Canada","authors":"Steven E. Zhang, Christopher J. M. Lawley, Julie E. Bourdeau, Mohammad Parsa, Renato Cumani, Aaron Thompson","doi":"10.1007/s11053-024-10451-0","DOIUrl":"https://doi.org/10.1007/s11053-024-10451-0","url":null,"abstract":"<p>Exploration for graphite in Canada is of economic, strategic and governance priority. In this study, we aimed to develop a reliable prospectivity map for graphite in Canada. Our approach mitigated multiple sources of workflow-induced uncertainty by propagating uncertainty due to the selection of negative labels, machine learning algorithms, feature space dimensionality, and hyperparameter tuning metrics. By averaging an ensemble of de-correlated models, we produced a single-merged model that clearly represents propagated uncertainty through a consensus map and an uncertainty map. These maps adhere to the metrological convention of \"result plus/minus associated uncertainty\" and are intuitive to use. Our ensemble demonstrated robustness, quickly converging to the consensus model, suggesting that new mineral prospectivity mapping (MPM) products using the same data would unlikely perturb our consensus model’s coverage. We conducted a maximally double-blind study, avoiding geoscientific knowledge during model generation to ensure impartial post-hoc analysis and interpretation. Therefore, our MPM products complement geoscientific knowledge-based exploration, because the targeting information provided in our MPM products constitute a maximally independent source. Our MPM products showed excellent spatial variability, aligning with existing knowledge of graphite deposits in Canada, indicating that combining data-driven rigor with independent interpretation enhances the robustness of our MPM products. Consequently, we believe our MPM products could effectively guide regional exploration of natural graphite in Canada.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"78 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143702910","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surface Movement Law Caused by Continuous Mining: A Case Study of Loess Plateau Coal Mines","authors":"Junlei Xue, Fuquan Tang, Qian Yang, Tao Yuan, Jiakun Gao, Chao Zhu, Yu Su, Ting Ma","doi":"10.1007/s11053-025-10479-w","DOIUrl":"https://doi.org/10.1007/s11053-025-10479-w","url":null,"abstract":"<p>The surface movement law induced by continuous mining across multiple working faces is distinct compared to that of a single working face. It is essential to understand and analyze this law to ensure the safety of coal mining operations. This study employed a research method that integrates numerical simulation and theoretical analysis to define, for the first time, the concepts of the repeated mining subsidence ratio and seemingly full mining. The analysis of ground surface movement in multiple mine working faces revealed that: The ground surface in multiple mine working faces within the Loess Plateau coal mines experienced multiple movements, with the center of subsidence deviating from the center of the working face. In the direction of surface inclination, the subsidence followed a cyclic pattern as it approached full mining, with the center of subsidence shifting away from the center of the mining area and positioning itself atop the spacer coal pillar. Multiple mine working faces intensify surface deformation and prolong surface movement. Spacer coal pillars between adjacent mine working faces provide structural support to surface subsidence deformation. Surface movement deformation results from the combined effects of slope slippage and mining-induced subsidence. The findings of this study establish a foundation for further research on surface movement and deformation in multiple mine working faces in the Loess Plateau coal mines.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"183 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fuzzy Classification of Mineral Resources: Moving Toward Overlapping Categories to Account for Geological, Economic, Metallurgical, Environmental, and Operational Criteria","authors":"Nadia Mery, Mohammad Maleki, Gabriel País, Andrés Molina, Alejandro Cáceres, Xavier Emery","doi":"10.1007/s11053-025-10470-5","DOIUrl":"https://doi.org/10.1007/s11053-025-10470-5","url":null,"abstract":"<p>A pivotal aspect in the evaluation of mining projects is the classification of mineral resources, which directly influences the definition of mineral reserves and significantly impacts mine planning and operational stages. However, the current classification methodologies often need specificity regarding the methods and parameters employed and heavily rely on the qualified/competent person’s judgment. This study addresses these gaps by proposing a pioneering fuzzy approach to assess grade and tonnage uncertainties. By allowing for overlapping resource categories and directly incorporating economic, geological, metallurgical, environmental, and operational criteria, we aim to provide tools for decision-making and for the final classification and public disclosure of mineral resources and reserves. We demonstrate the potential of our proposed methodology through an application to an iron ore deposit case study and through a detailed discussion on its uses, contributions, strengths, weaknesses, and on whether it complies with international reporting codes.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"24 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143672669","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sediment Instability Caused by Gas Production from Hydrate-Bearing Sediment in Northern South China Sea by Horizontal Wellbore: Sensitivity Analysis","authors":"Li Qingchao, Wu Jingjuan, Li Qiang, Wang Fuling, Cheng Yuanfang","doi":"10.1007/s11053-025-10478-x","DOIUrl":"https://doi.org/10.1007/s11053-025-10478-x","url":null,"abstract":"<p>Gas hydrate is anticipated to serve as a viable substitute for traditional fossil fuels in the near future. Unfortunately, some geomechanical issues may arise during its development, threatening its efficient development and the marine ecology. It is regrettable that research in this area remains inadequate. In the present work, a coupled mathematical model was used to analyze sediment stability during the prolonged extraction of natural gas from hydrate-bearing sediments. Moreover, the applicability of this model was verified by comparison. Based on this, the factors influencing sediment stability were then explored, and the corresponding mechanisms were thoroughly discussed. The comparison results showed that the results obtained by the mathematical model used were more accurate, as it included more physical fields and factors. Therefore, it was more suitable for numerical simulation of sediment stability during the long-term development of gas hydrates. Moreover, it was demonstrated that the strength weakening caused by hydrate dissociation and the stress change due to depressurization were two main mechanisms for sediment deformation or instability. Although gas production increased with increasing depressurization amplitude, permeability and hydrate saturation, as well as shallower reservoir depth, the sediment stability deteriorated accordingly. Interestingly, both sediment stability and gas production were unaffected by the heating amplitude during the prolonged development operation. This study offers a fresh perspective on mitigating the risk of sediment instability while ensuring the efficient development of marine hydrates.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"25 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143641050","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heterogeneity of Pore Structure in Braided River Delta Tight Sandstone Reservoirs: Implications for Tight Oil Enrichment in the Jurassic Badaowan Formation, Central Junggar Basin","authors":"Daiqi Ming, Xiangchun Chang, Fengkai Shang, Pengfei Zhang, Youde Xu, Yansheng Qu, Weizheng Gao, Tianchen Ge, Hongkang Zhao","doi":"10.1007/s11053-025-10476-z","DOIUrl":"https://doi.org/10.1007/s11053-025-10476-z","url":null,"abstract":"<p>The influence of diagenesis on the heterogeneity of pore structures in tight sandstone reservoirs is essential for accurately assessing hydrocarbon potential. This study employed polarized light microscopy and X-ray diffraction to characterize lithofacies in tight sandstones from the Jurassic Badaowan Formation in the Mo-Yong region of the central Junggar Basin. Additionally, the study integrated low-temperature nitrogen gas adsorption and mercury injection capillary pressure to comprehensively analyze pore structure attributes across various lithofacies within a braided river delta setting. Finally, the incorporation of a multifractal model allowed for a quantitative assessment of pore structure heterogeneity, examining the implications of diagenetic processes on the enrichment and distribution of tight oil. The investigations revealed significant variability in pore structures among lithofacies of the Badaowan Formation in the Mo-Yong region. Medium-coarse lithic sandstone (M-CLS) and medium feldspar–lithic sandstone (MFLS) predominantly feature meso-pores and macro-pores, playing a crucial role in hydrocarbon accumulation. In contrast, fine-medium feldspar–lithic sandstone (F-MFLS) and fine-medium calcareous sandstone (F-MCS) are characterized by the predominance of micro-pores, exhibiting weak connectivity. Feldspar dissolution markedly altered the pore architecture, notably enhancing the connectivity while reducing the heterogeneity of meso-pores and macro-pores. Secondary enlargement of quartz augmented the heterogeneity and reduced the connectivity of meso-pores and macro-pores, whereas the presence of micro-fractures in quartz could decrease this heterogeneity and enhance connectivity. Conversely, an increase in clay minerals and calcite reduced the volume and connectivity of meso-pores and macro-pores, thereby augmenting the heterogeneity of the pore structure. Multifractal analysis demonstrated the profound impact of diagenetic processes on the scale-dependent heterogeneity of pore structure, providing essential insights into the adsorption and flow mechanisms of tight oil within complex pore matrices. The analyses clearly identified variations in pore volume and heterogeneity across lithofacies as pivotal in governing the distribution of tight oil. Particularly, the well-developed meso-pores and their lower heterogeneities in MFLS designate it as the most prospective reservoir lithofacies. These findings offer new perspectives and solid theoretical support for the exploration and development strategies of deep tight sandstone reservoirs in braided river delta environment.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"19 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143618628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Predicting the Concentrations of Rare Earth Elements and Yttrium in Coal Using Self-Organizing Map","authors":"Na Xu, Fei Li, Wei Zhu, Mark A. Engle, Jiapei Kong, Pengfei Li, Qingfeng Wang, Lishan Shen, Robert B. Finkelman, Shifeng Dai","doi":"10.1007/s11053-025-10477-y","DOIUrl":"https://doi.org/10.1007/s11053-025-10477-y","url":null,"abstract":"<p>Several coals and coal by-products around the world have been identified as important alternative sources for rare earth elements and yttrium (REY) recovery, as these are considered crucial. However, many pre-existing coal chemical data and coal samples do not contain REY data, and in many cases, it is not possible to re-determine the REY concentrations in these samples. In this investigation, 528 coal samples collected from 36 coal mines of China were used to train a self-organizing map (SOM) model and the trained model was subsequently used to predict the REY concentrations in coal. The results were compared with the results of three other existing machine leaning methods, and the SOM model exhibited the highest accuracy in predicting REY concentrations. The trained SOM model was successfully used to predict REY concentrations in coal from the Fuqiang Mine, Hunchun Coalfield, northeastern China. The results were mostly consistent with those determined by an analytical technique. This work not only allows geologists to predict large-scale analysis of REY potential in coals but also improves our understanding to predict geochemical data using machine learning methods.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"17 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143607790","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of Grade on the Splitting Mechanical Properties of Iron Ore: Insights from Microstructure Analysis","authors":"You Ju, Aibing Jin, Yiqing Zhao, Shuaijun Chen, Shaokang Tang","doi":"10.1007/s11053-025-10469-y","DOIUrl":"https://doi.org/10.1007/s11053-025-10469-y","url":null,"abstract":"<p>The grade of iron content in ore was measured using X-ray fluorescence, and three iron ore grades (i.e., 28%, 34%, and 40%) were selected to prepare disk specimens. The Brazilian splitting test was performed, and acoustic emission and digital image correlation methods were used to capture the surface strain distribution and crack propagation behavior. The microscopic morphology of the fracture surfaces of specimens was analyzed using scanning electron microscopy, and the PFC (particle flow code) simulation was used to analyze the type of discrete fracture network in the specimens. The results showed that as the grade increased, the fracture zone shifted from the center to both sides, along with specimen tensile strength. This occurred because the iron oxide enrichment strength increases microscopically and is affected by the gradual increase in shear cracks and decrease in tensile cracks with increasing grade. Moreover, both the strain value of specimens and the speed of crack propagation increased with higher grades. Scanning electron microscopy revealed that microcracks on the fracture surface gradually change from pulse failure to transgranular failure, with the latter primarily comprising microcracks. By extending numerical simulations to 22% and 46% grades, it was found that the fracture surface became more prone to bilateral damage as the grade increased. The proportion of transgranular cracks increased from 8.9% to 33.8%. Additionally, the increase in the number of cracks accelerated microcrack propagation, leading to more severe fracture of the specimens.</p>","PeriodicalId":54284,"journal":{"name":"Natural Resources Research","volume":"31 1","pages":""},"PeriodicalIF":5.4,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143599247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}