Gas Science and Engineering最新文献

{"title":"Editorial of special issue “Advances in CCUS for the Natural Gas Industry”","authors":"Pål Østebø Andersen, Paweł Wojnarowski, Yen Adams Sokama-Neuyam, Furqan Le-Hussain, Jianchao Cai","doi":"10.1016/j.jgsce.2024.205463","DOIUrl":"10.1016/j.jgsce.2024.205463","url":null,"abstract":"","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"132 ","pages":"Article 205463"},"PeriodicalIF":0.0,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143163809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of reaction rate and pore structure heterogeneity on reactive solute transport in porous media","authors":"Mengzi Ren ,&nbsp;Liping Qiao ,&nbsp;Zhechao Wang","doi":"10.1016/j.jgsce.2024.205498","DOIUrl":"10.1016/j.jgsce.2024.205498","url":null,"abstract":"<div><div>CO₂ geological storage is the most direct and reliable method to reduce CO₂ emission, and deep saline aquifers have the greatest storage potential of CO₂. In the process of CO₂ storage in saline aquifers, mineral precipitation and dissolution caused by reactive solute transport have a significant impact on reservoir storage potential. In order to predict the transport characteristics and storage potential of CO₂ in saline aquifers, it is critical to understand the relationship between chemical reactions and transport properties. The governing equations of porosity evolution of porous media considering chemical reaction processes are proposed, and the relationship between effective reaction area and porosity is considered, and finally a kinetic model is established. Considering different reaction rates and different pore structure heterogeneity, the evolution characteristics of porosity, species concentration and fluid pressure were obtained by combining advection-diffusion equation and Darcy's law. The simulation results show that the dimensionless porosity of porous media transforms from uniform variation to extreme non-uniform variation under low <em>Da</em> number, typical <em>Da</em> number and high <em>Da</em> number condition. The dimensionless concentration can not reach the saturation concentration under low <em>Da</em> number condition. The dimensionless concentration decreases significantly in the inlet region and reaches the saturation concentration under typical <em>Da</em> number condition. The dimensionless concentration reaches the saturation concentration rapidly in the inlet region under high <em>Da</em> number condition. The variation of dimensionless pressure gradient in porous media is significantly correlated with the porosity distribution. The dimensionless advection mass flux of porous media is negatively correlated with the pore structure heterogeneity, while the dimensionless diffusion mass flux is positively correlated with the pore structure heterogeneity. The specie peak concentration decreased with increasing heterogeneity, and the time to reach the peak concentration increased with increasing heterogeneity. The research results can provide a theoretical foundation for the assessment of the transport pathways of CO₂ storage in saline aquifers.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"133 ","pages":"Article 205498"},"PeriodicalIF":0.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental investigation and predictive modeling of dry-out and salt precipitation effects during underground gas storage operations","authors":"Zhengshan Qin ,&nbsp;Yongming He ,&nbsp;Yangyang Ding ,&nbsp;Ning Wang ,&nbsp;Zhenjie Yao ,&nbsp;Lin Wu ,&nbsp;Xianshan Liu","doi":"10.1016/j.jgsce.2024.205503","DOIUrl":"10.1016/j.jgsce.2024.205503","url":null,"abstract":"<div><div>Formation damage poses the greatest threat to underground gas storage (UGS) operations, with permeability reduction being a key cause of injectivity and productivity losses. To better understand the mechanisms behind dry-out and salt precipitation (DSP) and predict the resulting near-wellbore damage, this study experimentally and quantitatively evaluates key factors affecting rock properties before and after salt precipitation. We conducted long-term gas-brine core flooding experiments, obtained salt-contaminated samples, and supplemented them with core permeability-porosity parameter tests, high-pressure mercury intrusion porosimetry (MIP), and scanning electron microscopy (SEM) experiments to better evaluate the salt clogging behavior of the samples. In addition, we discussed the applicability of the key parameter prediction model in modeling the DSP effects, including the water content of natural gas (WCNG), the porosity-permeability clogging model (PPC), and relative permeability (RP) function, providing usage recommendations. Based on our findings, we introduced a model to predict water saturation, salt saturation, and the salt-induced skin factor near the wellbore, particularly after viscous displacement ends, when liquid becomes immobile and evaporation dominates.</div><div>The results show that salt precipitation has a significant impact on core porosity and permeability. Notably, lower flow rates subtly promote salt precipitation by enhancing the role of evaporation, resulting in greater salt accumulation. In addition, elevated salinity and higher initial water saturation are key contributors to the precipitation process, further exacerbating salt buildup within the reservoir. MIP experiments further confirm the aforementioned impacts. SEM observations reveal NaCl crystals, either clustered or isolated, extensively distributed within the pores and filling the pore spaces from micro to nanometer scale, highlighting their substantial role in altering pore structure and impacting porosity and permeability due to DSP effects. Our developed model confirms that high temperature, low pressure, high flow rates, low initial porosity and permeability, and strong near-well inertia effects lead to DSP effects manifesting sooner near the wellbore during the post-viscous displacement stage. Model validation with core-scale predictions closely matches experimental data in terms of trend.</div><div>By laying the groundwork for analyzing the mechanisms of flow-through drying and salt precipitation, our findings can be directly applied to identifying the key controlling factors influencing DSP effects, mitigating formation damage, improving injectivity and productivity, and enhancing the efficiency of UGS operations under various operational conditions.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"133 ","pages":"Article 205503"},"PeriodicalIF":0.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722450","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A transient source-function-based embedded discrete fracture model for simulation of multiscale-fractured reservoir: Application in coalbed methane extraction","authors":"Tao Zhang ,&nbsp;Jianchun Guo ,&nbsp;Jie Zeng ,&nbsp;Hui Zhang ,&nbsp;Zhihong Zhao ,&nbsp;Fanhui Zeng ,&nbsp;Wenhou Wang","doi":"10.1016/j.jgsce.2024.205500","DOIUrl":"10.1016/j.jgsce.2024.205500","url":null,"abstract":"<div><div>The classic embedded discrete fracture model (EDFM) may cause certain errors when simulating the transient flow process within the multi-scale fractured system. In this study, the transient transmissibility was derived by using the point (matrix-fracture) and line (fracture-fracture) source functions. The transient source-function-based EDFM (tSEDFM) is established via this method. Then, based on the dual criteria that <em>d</em>_NNC is less than a certain distance and its projection point is within the corresponding fracture domain, a 3D fracture meshing method for arbitrary fracture geometry and orientation is established. The finite volume method is used to discrete the fluid flow equations for matrix and fracture systems, considering the multi-deformation-induced permeability evolution. Consequently, the numerical simulation framework of FVM-tSEDFM is proposed to investigate the transient mass transfer characteristics. Compared with the current pEDFM, the pressure drop near fractures of the proposed model is higher and the gap narrows as pressure wave further spreads. Compared with AEDFM, the <em>T</em>_mf of tSEDFM is almost the same, but AEDFM's <em>T</em>_ff is substantially higher in the initial stage and the attenuation rate is slower, resulting in an error of nearly 15% at the hydraulic fracture location. As fracture density increases, more transient flow makes AEDFM- and EDFM-calculated BHP values deviate from tSEDFM. History matching using the tSEDFM with only 10000 meshes shows better results where the mismatching rate is larger than 90%. Simulation of CBM extraction indicate that sharp pressure decline occurs near the fractures, resulting in gas desorption enhancement and rapid productivity increment. The tSEDFM demonstrates good practicality in calculating the production and long-term permeability evolution. Results also show that the tSEDFM can correct the underestimation of mass exchange in the early stage and overestimation since the pseudo-steady stage, and can be better applied to the numerical simulation of multi-scale fractured reservoirs. As the dominant factor for gas extraction, sensitivity analyses of fracture properties are also documented.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"133 ","pages":"Article 205500"},"PeriodicalIF":0.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697519","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Critical review on wettability, optimal wettability, and artificial wettability alteration in rock-brine-CO2 systems for geologic carbon sequestration","authors":"Abouzar Mirzaei-Paiaman ,&nbsp;Ryosuke Okuno","doi":"10.1016/j.jgsce.2024.205499","DOIUrl":"10.1016/j.jgsce.2024.205499","url":null,"abstract":"<div><div>Sequestration of carbon dioxide (CO₂) in deep saline aquifers is an approach to addressing the increasing level of atmospheric CO₂. Rock wettability influences various aspects of sequestration processes, including CO₂ trapping mechanisms, migration rate, spatial distribution, injection rate, and injectivity loss due to dry-out and salt precipitation around injectors. We present a critical review of wettability within rock-brine-CO₂ systems, covering existing experimental data on storage and seal rock wettability, optimal wettability states for different aspects of geological CO₂ sequestration (e.g., injectivity and storage/sealing capacity), and artificial wettability alteration for improving performance metrics of CO₂ sequestration. Our findings are threefold. First, the wettability of aquifer rocks is highly uncertain and should be cautiously assumed to potentially change from water-wet to CO₂-wet. We recommend studying wettability within rock pores through advanced imaging techniques or relative permeability-based wettability indices whenever possible by using chemically preserved subsurface samples and testing under representative subsurface conditions. Second, the optimal wettability for sealing rock and injectivity is water-wetness and CO₂-wetness, respectively. However, determining the optimal wettability for a storage rock remains an open question, and water-wetness is not necessarily more advantageous than CO₂-wetness for more secure storage of CO₂. Third, given the unclear relationship between wettability and trapping mechanisms, the artificial alteration of wettability toward water-wetness, as proposed in the literature, may even result in adverse effects on storage security and injectivity. Any artificial wettability alteration should be carefully designed on a case-by-case basis due to the diverse aspects of CO₂ injection and storage.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"132 ","pages":"Article 205499"},"PeriodicalIF":0.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700355","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on resistivity characteristics of grain-coating and pore-filling hydrates in different sediment packings based on voxelated 3D models","authors":"Jilun Weng ,&nbsp;Tao He","doi":"10.1016/j.jgsce.2024.205501","DOIUrl":"10.1016/j.jgsce.2024.205501","url":null,"abstract":"<div><div>Natural gas hydrate is a clean energy resource with abundant reserves. Before conducting large-scale exploitation, understanding its physical properties, such as electrical properties, is crucial for gas reserve evaluation and production process monitoring. Due to the complexity of the pore space geometry and different hydrate growth morphology, electrical resistivity may vary for different samples at the same hydrate saturation. This study considered three packings of unconsolidated marine sediment grains (simple cubic, body-centered cubic, and face-centered cubic) and two end distribution patterns of hydrates in pores (grain-coating and pore-filling). The original 3D geometries of hydrate-bearing models were replaced with voxelated meshes to achieve better stability and versatility. The resistivities of models were calculated using the finite element method and compared with the results from Archie's law. The simulation results show that the resistivity curve's shape is jointly affected by the hydrate distribution pattern and the initial pore space geometry. A rational function can be used to fit the saturation exponent curves to give critical brine saturations. The grain-coating hydrate prefers blocking the throats and has a critical brine saturation above 0. In contrast, the pore-filling hydrate has resistivities lower than the Maxwell-Garnett equation's lower boundary due to a bypassing effect, which partially compensates for the conductivity loss of the pore fluid and is more remarkable for models distributed by bigger hydrate particles, and has a critical brine saturation equal to 0. The findings are helpful in understanding the non-Archie phenomenon of hydrate-bearing sediments.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"133 ","pages":"Article 205501"},"PeriodicalIF":0.0,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Life cycle assessment of CO2 capture through pressure swing adsorption using MOF-74","authors":"Pin Wang ,&nbsp;Zhen Pan ,&nbsp;Zhiming Liu ,&nbsp;Liyan Shang ,&nbsp;Mohamad Reza Soltanian ,&nbsp;Zhien Zhang","doi":"10.1016/j.jgsce.2024.205497","DOIUrl":"10.1016/j.jgsce.2024.205497","url":null,"abstract":"<div><div>Carbon Capture and Storage (CCS) technology is regarded as one of the critical measures to mitigate global climate change. Within CCS technology, the selection and performance of adsorbents play a key role in overall efficiency and environmental impact. This paper systematically evaluates the environmental impacts of MOF-74 series adsorbents used in CO₂ capture through a Life Cycle Assessment (LCA) and compares the results with those of monoethanolamine (MEA)-based chemical absorption technology. The study examines the production, use, and regeneration stages of MOF-74 adsorbents, quantifying energy consumption, greenhouse gas emissions, and other related environmental impacts at each stage. The results indicate that Zn-MOF-74 performs excellently, with various midpoint indicators being on average 40% lower than those of Mg-MOF-74. Sensitivity and uncertainty analyses reveal that the resource consumption and environmental burden during the MOF-74 production process are high and significantly affected by the yield of MOF-74. Due to the use of ethanol in its synthesis, Ni-MOF-74 exhibits a high degree of uncertainty regarding its environmental impact. Additionally, while the energy consumption of MOF-74 adsorbents during regeneration is relatively low, it still falls short compared to MEA, indicating the need for further optimization to reduce overall environmental impacts. This study provides a comprehensive LCA of MOF-74 series adsorbents, offering a systematic comparison of their environmental impacts and providing a scientific basis for the future development of CO₂ capture technologies and adsorbent selection.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"133 ","pages":"Article 205497"},"PeriodicalIF":0.0,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142743996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pressure distributions and flow regimes: An integrated approach for CO2 sequestration project design and evaluation in hydraulically fractured shale reservoirs","authors":"Salam Al-Rbeawi","doi":"10.1016/j.jgsce.2024.205495","DOIUrl":"10.1016/j.jgsce.2024.205495","url":null,"abstract":"&lt;div&gt;&lt;div&gt;This paper introduces an integrated approach for estimating the key parameters of CO&lt;sub&gt;2&lt;/sub&gt; storage projects in depleted hydraulically fractured shale reservoirs. The approach focuses deep insights into evaluating these projects based on the pressure distribution and flow regimes. The objective is reducing the uncertainties in the design and evaluation criteria of CO&lt;sub&gt;2&lt;/sub&gt; storage by better understanding the flow mechanisms in the porous media. This understanding helps in perfectly modeling CO&lt;sub&gt;2&lt;/sub&gt; distribution and characterizing the expected flow regimes.&lt;/div&gt;&lt;div&gt;Several analytical models are developed for the pressure behavior of CO&lt;sub&gt;2&lt;/sub&gt; multi-size scale flow mechanisms. Diffusion flow, slip flow, adsorption flow, and Darcy and non-Darcy flow are all considered. The flow in the nano-size organic particles, the micro-size kerogen particles, and the macro-size matrix is analytically described. The flow inside natural fractures in the stimulated and unstimulated reservoir volume as well as the flow of CO&lt;sub&gt;2&lt;/sub&gt; in the hydraulic fractures are modeled. Several rectangular reservoir configurations, hydraulic fracture characteristics, and petrophysical properties of the matrix, kerogen, and organic matter are examined. An estimation model for the total volume of CO&lt;sub&gt;2&lt;/sub&gt; that could be stored in the depleted fractured reservoirs is presented. The contribution of the unstimulated and stimulated porous media as well as the hydraulic fractures to the total volume is determined by characterizing the flow regimes. Different models are proposed for the time at which CO&lt;sub&gt;2&lt;/sub&gt; reaches the hydraulic fracture tips, the borders between stimulated and unstimulated porous media, and the reservoir boundary. Profound explanations are introduced for the impact of the constrained pressure on the total capacity of the reservoirs for CO&lt;sub&gt;2&lt;/sub&gt; storage.&lt;/div&gt;&lt;div&gt;The study has reached several conclusions. The characteristics of the organic matter, kerogen, and the micro-size scale matrix do not significantly impact the pressure distribution and flow regimes. Conversely, the pressure distribution and flow regimes are significantly impacted by the characteristics of the hydraulic and natural fractures. The hydraulic fractures may offer a reasonable capacity for CO&lt;sub&gt;2&lt;/sub&gt; storage, meanwhile, the capacity of stimulated and unstimulated reservoir volume is controlled by reservoir configuration and fracture spacing. The constrained pressure may strictly reduce the total capacity of CO&lt;sub&gt;2&lt;/sub&gt; storage in the reservoir. The total volume of the injected CO&lt;sub&gt;2&lt;/sub&gt; can be determined from the pressure point when the injection pulse has reached to reservoir boundary. Beyond this point, it is not recommended to inject CO&lt;sub&gt;2&lt;/sub&gt; as it could increase reservoir pressure more than initial pressure. The pressure of the depleted reservoir before injection is a key parameter in the design and evaluation of the CO&lt;su","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"133 ","pages":"Article 205495"},"PeriodicalIF":0.0,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142697520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Insights of physicochemical structure changes of bituminous coal with acidification-assisted controlled electric pulse through SEM, XRD and FTIR","authors":"Fazhi Yan ,&nbsp;Changjiong Gao ,&nbsp;Shoujian Peng ,&nbsp;Xuelin Yang ,&nbsp;Ziwen Li ,&nbsp;Mengmeng Yang ,&nbsp;Tao Zeng ,&nbsp;Yongdan Yang","doi":"10.1016/j.jgsce.2024.205496","DOIUrl":"10.1016/j.jgsce.2024.205496","url":null,"abstract":"<div><div>Controlled electric pulse (CEP) cracking coal effectively enhances its permeability, but a high coal breakdown voltage (BV) can result in technical difficulties. To address this problem, the method of using HCl solution to improve the electrical conductivity of coal was proposed. The effects of HCl on coal BV were investigated, and the microstructural changes in coal were analyzed through scanning electron microscopy, X-ray diffraction, and Fourier-transform infrared spectroscopy. Compared with raw coal, the BV of acidified coal decreased significantly. The crushing degree of the coal samples was clearly enhanced with an increasing HCl concentration. Some internal coal minerals were acidified and dissolved, the aromatic layer spacing (<em>d</em>_<em>002</em>) increased and the layer sheet stacking height (<em>L</em>_<em>c</em>) decreased, and the crystal structure was damaged. When acidified coal was broken down, numerous internal pores and cracks appeared, active coal groups were shed, the aliphatic hydrocarbons and oxygen-containing functional group contents increased, surface activity was reduced, and the hydroxyl content was reduced, which was conducive to rapid gas desorption. Acidification effectively reduces the BV of coal and improves the cracking and permeability enhancement effect of coal by CEP action.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"132 ","pages":"Article 205496"},"PeriodicalIF":0.0,"publicationDate":"2024-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Method for identifying the leakage of buried natural gas pipeline by soil vibration signals","authors":"Hongqiang Ma ,&nbsp;Yan Zhong ,&nbsp;Jiajun Wang ,&nbsp;Yue Xie ,&nbsp;Ruixiang Ding ,&nbsp;Huilun Kang ,&nbsp;Yue Zeng","doi":"10.1016/j.jgsce.2024.205487","DOIUrl":"10.1016/j.jgsce.2024.205487","url":null,"abstract":"<div><div>To simplify the process of leakage characteristics, an artificial intelligence method is proposed for identifying buried natural gas pipeline leakage based on the wavelet transform and the Symmetrized Dot Pattern (SDP) algorithm in this paper. The method consists of three components: signal de-noising, feature extraction and leakage identification. In signal de-noising, the wavelet function is selected based on wavelet entropy, while the exponential threshold function is utilized to improve wavelet threshold de-noising. It is found that Daubechies18 (Db18) is the optimal wavelet function for soil vibration signals, characterized by an entropy value of 13.539 and effective frequency components below 1000 Hz. Feature extraction is based on the SDP algorithm with the angle amplification factor and time interval coefficient set as 35° and 2. This algorithm converts one-dimensional signals into two-dimensional images, showing that the SDP points of leakage signals concentrate at <em>r</em> = 0.2–0.8, distinguishing them from environmental noise. Regarding leakage identification, a model based on SDP images is proposed for classifying the signal images of buried natural gas pipelines. It is optimized in terms of network structure, hyperparameters, and training. The results show that the suitable model has four convolutional layers, four pooling layers, two fully connected layers and softmax with the accuracy of 94.71%. Furthermore, the Area Under Curve (AUC) values are higher than 0.95 under different conditions, with both the accuracy and F1 value errors within ±1%. In spite of only being tested under specific conditions, the method still offers guidance for leak detection in buried natural gas pipelines.</div></div>","PeriodicalId":100568,"journal":{"name":"Gas Science and Engineering","volume":"132 ","pages":"Article 205487"},"PeriodicalIF":0.0,"publicationDate":"2024-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142655747","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}