Natural Gas Industry B最新文献

{"title":"Multifractal characteristics of nanopores in the Zhaotong national shale gas demonstration area, Southern Sichuan Basin, China","authors":"Yangming Li ,&nbsp;Ziqi Feng ,&nbsp;Qin Zhang ,&nbsp;Shang Xu ,&nbsp;Wei Wang ,&nbsp;Hao Li ,&nbsp;Shangwen Zhou","doi":"10.1016/j.ngib.2025.11.008","DOIUrl":"10.1016/j.ngib.2025.11.008","url":null,"abstract":"<div><div>The multifractal characteristics of organic-rich shale developed along the margins of basins are essential for understanding reservoir heterogeneity, gas storage mechanisms, and the identification of favorable exploration targets. This study systematically investigates the pore structure of marine shale in the Zhaotong area of the National Shale Gas Exploration Demonstration Area in China by integrating analytical methods such as X-ray diffraction, low-pressure N₂ adsorption, and field emission scanning electron microscopy with the Frenkel-Halsey-Hill fractal model. The results reveal that: (1) four distinct shale lithofacies (SL) types were identified—argillaceous/siliceous mixed SL (Type I: M-2), carbonate/siliceous mixed SL (Type II: M and M-1), argillaceous-rich siliceous SL (Type III: S-3), and carbonate-rich and argillaceous/carbonate siliceous SL (Type IV: S-1 and S-2); (2) Types II and IV generally exhibit higher fractal dimensions (D₁, D_2, and D₃) than Types I and III, indicating the former’s more complex pore architectures, rougher pore surfaces, and greater potential for gas adsorption; (3) for Types I and III, fractal dimensions exhibit positive correlations with organic matter content, pore structural parameters, and gas content, suggesting their effectiveness as indicators of reservoir quality. In contrast, in Types II and IV, the D₂ dimension is positively correlated with gas content, implying that mesopores play a significant role in gas occurrence, even in tectonically modified settings. These results highlight the utility of fractal analysis as a robust method for evaluating reservoirs in structurally complex geological environments.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 6","pages":"Pages 647-661"},"PeriodicalIF":6.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145871743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Limit analysis of extended-reach drilling considering the coupling effects of hydraulic energy loss and transient cuttings transport","authors":"Jun Zhao ,&nbsp;Wenjun Huang ,&nbsp;Deli Gao ,&nbsp;Weiguo Zhang ,&nbsp;Chenghui Deng ,&nbsp;Kun Zuo","doi":"10.1016/j.ngib.2025.11.006","DOIUrl":"10.1016/j.ngib.2025.11.006","url":null,"abstract":"<div><div>Ultradeep extended-reach drilling has become the most effective engineering method for economically developing marginal reservoirs in the eastern South China Sea. However, complications, including poor hole cleaning, high pressure loss, and high pump pressure, pose serious threats to the safe and efficient drilling of large-hole sections (i.e., 17¹/₂-in. and 12¹/₄-in. section) with steep inclinations, constraining hydraulic extension limits. In this article, we present a hydraulic extension limit model for extended-reach wells, mainly considering the constraints of rated pump pressure, the safety density window of a formation, cuttings transport, and so on. The key to calculating the hydraulic limit was to obtain the distributions of hydraulic pressure in relation to a cuttings bed throughout an entire wellbore. We then built a mechanical coupling model of annular pressure and transient cuttings transport to overcome the shortcomings of relatively independent calculations of annular pressure and cuttings distribution. A case study showed that variations in drilling parameters during drilling caused corresponding alterations in the cuttings bed distribution. This affected the bottom-hole ECD (Equivalent Circulating Density) and surface SPP (Standpipe Pressure), explaining significant fluctuations in the measurement data. The hydraulic extension limit relates closely to various drilling parameters. Based on the results of a sensitivity analysis, we optimized these drilling parameters. For a 12¹/₄-in. section, the recommended mud displacement was 70 L/s, the recommended ROP (Rate of Penetration) was 50 m/h, and the recommended mud density was 1100 kg/m³. Using these recommended operating parameters increased the hydraulic limit by about 2.19 km.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 6","pages":"Pages 689-704"},"PeriodicalIF":6.5,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145871746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Risk assessment and prevention measures for casing deformation in the geological–engineering integration of a block in Jiaoshiba shale gas field","authors":"Yunhong Xie ,&nbsp;Jian Liu ,&nbsp;Li Wang ,&nbsp;Zhonghui Li","doi":"10.1016/j.ngib.2025.09.007","DOIUrl":"10.1016/j.ngib.2025.09.007","url":null,"abstract":"<div><div>Casing deformation is a widespread problem in a certain block of Jiaoshiba Shale Gas Field in Sichuan Basin, China, and it severely limits the development benefits of shale gas in that block. Based on the spatiotemporal characteristics of block formation, fracture development, and casing deformation occurrence, this paper employs an integrated geological–engineering research approach to identify the primary mechanisms governing casing deformation within the block and proposes countermeasures to prevent such deformation. The present research indicates the following findings: (1) The block has undergone multiple phases of tectonic superposition, with fracture development serving as the geological factor causing casing deformation. (2) Fracturing activation constitutes the engineering factor causing casing deformation, with 4 mm of formation slip inducing deformation. (3) The fracture activation risk map shows that Class I and Class II fractures account for 73.36 % of the total recorded in the block. Within the most susceptible Class I risk zone, the critical activation pressure increment for fracturing operations ranges from 13.43 MPa to 13.99 MPa. Based on the distribution of casing failure risk zones identified in the fracture activation risk map, this paper proposes relevant technical countermeasures for preventing casing failure from three perspectives: shale gas well location deployment, drilling techniques, and fracturing techniques. These measures provide robust support for safeguarding the integrity of casing systems within the studied block.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 5","pages":"Pages 623-635"},"PeriodicalIF":6.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145398403","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Global liquefied natural gas market development and future outlook","authors":"Kai Wang,&nbsp;Sixing Zhao,&nbsp;Zhen Wang","doi":"10.1016/j.ngib.2025.10.001","DOIUrl":"10.1016/j.ngib.2025.10.001","url":null,"abstract":"<div><div>Since 2020, the global energy market has faced persistent disruptions due to geological tensions and the economic competition among great nations, with liquefied natural gas (LNG) emerging as a vital instrument in balancing energy security and transition within the global carbon neutrality framework. This study reviewed the global LNG market from 2020 to 2024 through prices, trade flows, liquefaction capacity, shipping, and regasification infrastructure to provide medium- and long-term market outlooks in terms of supply, demand, trade, liquefaction capacity, and prices. The following research results were obtained: (1) The global LNG market underwent profound reconstruction between 2020 and 2024, with natural gas prices retreating sharply after a period of extreme volatility. (2) LNG trade flows were fundamentally reshaped by a pronounced shift toward Europe, disrupting the traditional Asia-centric landscape. (3) Liquefaction capacity growth decelerated, with the United States surpassing Australia to become the world's largest market in terms of liquefaction capacity. (4) Global natural gas production is poised for steady growth, while demand retains substantial potential, driven by both economic expansion and energy transition. (5) A forthcoming wave of liquefaction projects is expected to create a less restricted supply-demand market balance, which would likely lead to diverging price paths and narrower spreads between major hubs. The LNG industry faces promising opportunities from energy transition and digitalization, particularly for floating storage regasification units and small-scale LNG, while confronting major challenges, including persistent geopolitical tensions, shipping route uncertainties, and increasing dependence on the pace of renewable energy deployment.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 5","pages":"Pages 636-646"},"PeriodicalIF":6.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145398404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Gas compositional and isotopic variation during desorption of middle-upper Permian shales in western Hubei, Southern China","authors":"Le Li ,&nbsp;Huan Yang ,&nbsp;Zilong Ju ,&nbsp;Yasheng Cui ,&nbsp;Jie Xin ,&nbsp;Xiaogui Peng ,&nbsp;Boyong Yang ,&nbsp;Yanlin Zhang ,&nbsp;Yuanqing Hu ,&nbsp;Feng Yang","doi":"10.1016/j.ngib.2025.09.006","DOIUrl":"10.1016/j.ngib.2025.09.006","url":null,"abstract":"<div><div>Significant progress has been made in exploring shale gas resources in the middle-upper Permian strata of western Hubei. However, the unclear geochemical characteristics and origins of the gas have hindered a comprehensive understanding of reservoir evolution and have constrained integrated resource development. This study involved a 28-h desorption experiment in which gases released from shales of the Dalong and Gufeng Formations were systematically collected for compositional and carbon–hydrogen isotope analyses. Comparing the compositional and geochemical characteristics of the desorbed gases and investigating their genetic origins resulted in four main findings: (1) Gas composition during the middle stage of desorption, excluding H₂S, best represents the original reservoir fluid, with component variations linked to adsorption and diffusion capacities. (2) Both shales display similar gas compositions with trace H₂S; the Dalong shale contains lower CH₄, CO₂, and H₂S but higher C₂H₆ and N₂. (3) Carbon and hydrogen isotopes indicate oil-type thermogenic gases, with carbon isotope reversal reflecting tectonic uplift, depressurization, and the mixing of primary kerogen-derived and secondary oil-/condensate-derived gases. (4) N₂ likely originates from ammonium-bearing silicate decomposition, CO₂ is mainly inorganic, from thermal carbonate decomposition with minor organic contribution, and H₂S may result from oil cracking or thermochemical sulfate reduction. This study provides a comprehensive record of the fluid characteristics of middle-upper Permian shale gas reservoirs and enhances the understanding of their formation and evolution.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 5","pages":"Pages 557-571"},"PeriodicalIF":6.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145398399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Diagenetic facies, volcanic tuffaceous sediment, and its diagenetic features in deeply buried tight sandstone, Shan 2 and He 1 Members, Ordos Basin, China","authors":"Zhiyuan Lu ,&nbsp;Zhiliang He ,&nbsp;Guangyou Zhu ,&nbsp;Jie Zhu ,&nbsp;Jon Gluyas ,&nbsp;Guangxiang Liu ,&nbsp;Wanyan Lan","doi":"10.1016/j.ngib.2025.09.003","DOIUrl":"10.1016/j.ngib.2025.09.003","url":null,"abstract":"<div><div>Understanding diagenetic processes plays a crucial role in evaluating the quality of tight reservoirs. In this study, we aimed to examine diagenetic facies and thereby assess reservoir quality by conducting an integrated analysis of porosity, petrology, permeability, mineralogy, mercury injection, and stable isotopic data in core samples from the Permian Shan 2 and He 1 members (Shan 2–He 1 Mbr) in China's Ordos Basin. Early compaction and precipitation of diagenetic minerals have significantly reduced primary pore space in these members, although certain sandstones have retained anomalously high porosity. These high-porosity reservoirs have been shaped by many factors, with dissolution identified as the predominant mechanism. Detailed petrographic observations and assessments of the primary minerals, the minerals' genesis, and associated diagenetic processes revealed seven distinct diagenetic facies differentiated by their sand-grain populations, types of cementation, clay matrix contents, and volcanic tuffaceous sediment (VTS). The main interstitial fillings consist of VTS, clay minerals, quartz overgrowths, and calcite (ferrocalcite). Clasts and VTS-dissolved sandstone have mainly formed Class I reservoirs with highly unstable grains and good secondary pores resulting from the dissolution of the grains and VTS. VTS tight sandstone, siliceous cementation tight sandstone, illite-siliceous cementation tight sandstone, and calcite cementation tight sandstone have formed Class II reservoirs with high rates of interstitial filling and cementation. Sandstone tightly cemented by illite has poor reservoir properties and has mainly formed Class III reservoirs. This classification underscores the critical importance of understanding diagenesis, diagenetic facies, and especially the diagenetic features of VTS for accurately assessing reservoir quality. A comprehensive understanding of these factors may facilitate more effective hydrocarbon exploration and exploitation in this area.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 5","pages":"Pages 527-542"},"PeriodicalIF":6.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145398406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic sources of natural gas in new exploration strata in the piedmont area of southwestern Tarim Basin","authors":"Yu Xiao ,&nbsp;Qiang Meng ,&nbsp;Xiang Wang ,&nbsp;Xiaomin Xie ,&nbsp;Cai Chen ,&nbsp;Qilin Xiao ,&nbsp;Guo Chen ,&nbsp;Zhanghu Wang","doi":"10.1016/j.ngib.2025.09.002","DOIUrl":"10.1016/j.ngib.2025.09.002","url":null,"abstract":"<div><div>Despite its significant exploration potential, the origin of natural gas in the tectonically complex southwestern Tarim Basin remains controversial due to multiple potential source rocks. This study identifies the genetic types and sources of natural gas by integrating gas molecular and isotopic compositions with the geochemical characteristics of potential source rocks. The results indicate that the Kekeya gas field mainly contains coal-derived gas sourced from the Permian Pusige Formation, whereas the Akemomu field and the QT-1 well contain highly overmature gas from the Permian Qipan Formation with some mantle-derived He and inorganic CO₂. Furthermore, the oil-associated gas in the FS-8 well originates from Permian sapropelic source rocks, while the KS-6 well contains a mixed, oil-associated gas predominantly sourced from the Jurassic Yangye Formation. These findings reveal a complex gas accumulation scenario with multiple genetic types and sources in the southwestern Tarim Basin, providing critical insights for future exploration.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 5","pages":"Pages 543-556"},"PeriodicalIF":6.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145398407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paleo-environmental and geological characteristics of Wufeng-Longmaxi marine shale in different paleo-geomorphological units, Eastern Sichuan Basin, China","authors":"Zhanlei Wang ,&nbsp;Ruiqian Zhao ,&nbsp;Licheng Yang ,&nbsp;Hongchuan Yin ,&nbsp;Wen Tang ,&nbsp;Dongxi Liu ,&nbsp;Yifan Gu ,&nbsp;Yuqiang Jiang","doi":"10.1016/j.ngib.2025.09.001","DOIUrl":"10.1016/j.ngib.2025.09.001","url":null,"abstract":"<div><div>The Wufeng-Longmaxi marine shale in the Eastern Sichuan Basin is the key target for shale gas exploration in China. Based on logging response and lithofacies type, three paleo-geomorphological units are identified in the deep-water shelf during the Wufeng-Longmaxi deposition: subaqueous slope (SS), subaqueous plain (SP), and subaqueous sub-sag (SSS). Using methods such as mercury intrusion porosimetry (MIP), field emission scanning electron microscopy (FE-SEM), nuclear magnetic resonance (NMR), and X-ray diffraction (XRD), the differences of environmental conditions, mineral composition, organic matter (OM) content, and pore structure in different units are determined, and the factors controlling the differences in shale reservoirs are discussed. The results show that redox conditions of bottom water and productivity of surface water affect OM enrichment, resulting in SSS being the most organic-rich unit. Terrigenous detrital input affects mineral composition in different units, and SSS is the most quartz-rich unit. From SS to SSS shale, the proportion of OM pores gradually increased, while the proportion of inorganic pores and microfractures gradually decreased. The pore size distribution dominated by mesopores in SP and SSS shale is generally consistent, much higher than in SS. The differences in sedimentary environments result in differences in reservoir quality. The OM and brittle mineral content in SSS are relatively high, which is beneficial for reservoir development. SSS has the best environmental conditions; therefore, the quality of the marine shale reservoirs formed is the best.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 5","pages":"Pages 572-584"},"PeriodicalIF":6.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145398400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Seismic sedimentological-based quantifications of late-Cretaceous hydrocarbon-bearing late-aggradational lowstands prograding wedges in the Indus basin: Frequency-controlled porosity-constrained dynamic simulations","authors":"Muhammad Tayyab Naseer","doi":"10.1016/j.ngib.2025.09.004","DOIUrl":"10.1016/j.ngib.2025.09.004","url":null,"abstract":"<div><div>Seismic quantitative reservoir simulations and characterizations have played a vital role in exploring stratigraphic traps, such as late-aggradational lowstands prograding wedge systems (LPWS) within lowstands systems tracts (LST). However, seismic data acquisition operations are always dominated by exceptional seismic coherent noise events, e.g., multiples, which reduce the signal strengths of the source-generated incident seismic waves within vertically and laterally heterogeneous earth systems. Hence, these noise events create hurdles in predicting paleo-depositional impedance (PDI), paleo-thickness (PTS), paleo-dense fractured networks, erosional and depositional zones, fault-controlled migrations, and types of seismic reflection configurations (SRFC), which are key elements in developing stratigraphic pinch-out traps. This research utilizes the state-of-the-art technologies of spectral wavelet-based instantaneous time-frequency analysis and seismic waveform frequency-controlled porosity-constrained static reservoir simulation (FDPVS) tools to quantify the LPWS inside the Onshore Basin, Pakistan. The use of conventional amplitude-based seismic attributes, such as the average energy, remained a better tool for deciphering the overall geological architecture of the LPWS. Conventional FDPVS realizations resolved a PDI of −1.391 gm./c.c.∗m/s to −0.97 gm./c.c.∗m/s for LPWS with PTS of 12 and 20 m, respectively. A 0.9 km lateral extent of paleo-dense fractured networks (PDFN) with a strong linear regression R² = 0.93 was also resolved. Average energy attribute-based instantaneous frequency FDPVS realizations enabled the imaging of parallel-to-prograding SRFC with resolved magnitudes of −0.259 gm./c.c.∗m/s for PDI, 20 m for PTS, and 0.73 km for PDFN with linear regression transforms at R² = 0.92, which indicates the deposition of onlap fill facies inside the LPWS during extensive sea-level fall. These realizations have also resolved frequency-controlled fault migrations on 27-Hz spectral waveform-based amplitude plots with 2.174 gm./c.c.∗m/s PDI for conduit fault systems and 27-Hz with 0.585 gm./c.c.∗m/s PDI for sealing fault systems. All these structural configurations are completely sealed up by transgressive seals of transgressive systems tracts and, hence, developed into pure stratigraphic-based oil and gas plays. This research has strong implications for side-tracking drilling locations and provides an analogue for basins with similar geology and stratigraphy worldwide.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 5","pages":"Pages 585-606"},"PeriodicalIF":6.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145398401","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Coal permeability evolution under coupled mining disturbance and gas extraction conditions: An experimental study","authors":"Zihao Kan ,&nbsp;Lei Zhang ,&nbsp;Xinyuan Liu ,&nbsp;Chen Wang ,&nbsp;Dingyi Hao ,&nbsp;Zhiwei Ye","doi":"10.1016/j.ngib.2025.09.005","DOIUrl":"10.1016/j.ngib.2025.09.005","url":null,"abstract":"<div><div>This study investigates the evolution of coal permeability under mining-induced stress and gas extraction, a key factor for safe and efficient coal seam gas recovery. A simplified triaxial stress path incorporating axial stress, confining stress, and pore pressure was applied to simulate stress relief and gas drainage in protective seam mining. Laboratory experiments on intact and fractured coal samples from the Huainan mining area were conducted using a gas-flow and stress-controlled loading system. Results indicate that coal permeability is strongly dependent on loading history and fracture morphology. The first unloading cycle produced the largest fracture volume reduction (29 % in vertically fractured coal, 23 % in horizontally fractured coal, and 20 %–21 % in intact coal). Irreversible permeability loss correlated with initial porosity, while the third cycle yielded the greatest permeability increase due to cumulative damage and new fracture formation. Decreasing pore pressure amplified its influence on permeability, with intact coal showing higher stress sensitivity and fractured coal exhibiting a declining trend under cyclic loading. Unlike previous studies that focused primarily on monotonic loading or single fracture orientations, this work systematically reveals the fracture-dependent, cyclic nature of permeability evolution under coupled mining stress and gas drainage conditions. These findings highlight the nonlinear, fracture-dependent nature of coal permeability evolution and provide guidance for optimizing gas drainage, enhancing methane recovery, and improving safety in deep coal mining.</div></div>","PeriodicalId":37116,"journal":{"name":"Natural Gas Industry B","volume":"12 5","pages":"Pages 607-622"},"PeriodicalIF":6.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145398402","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}