The purpose of this study is to explore the development depth of rock layer rupture and analyze the developmental regularity of mining floor in Dongsi mining area of Xinzhi Coal Mine. Two kinds of pressure water testing methods and numerical simulation are used to study the failure characteristics of the bottom plate of the working face in Dongsi mining area of Xinxian Coal Mine. The results show that the failure of working face bottom plate starts from a certain range in front of the working face. With the advance of working face, the failure depth of mining bottom plate increases continuously. At the same time, the failure range of mining roadway is slightly larger than the failure range of working face bottom plate due to the double disturbance of tunneling and mining. The pressure water test shows that the rupture depth occurs at 8.98-9.03 m. The numerical simulation results of floor failure depth show that its depth is about 8.7 m, which is basically consistent with the pressure water test. It provides a reference for the advanced preexploration of mining bottom plate failure in similar coal seam.
{"title":"Damage Depth Test and Numerical Simulation of Stope Floor in Mining Face","authors":"Xipeng Cui, Hongqi Shao, Kailei Zhao","doi":"10.1155/2023/2184880","DOIUrl":"https://doi.org/10.1155/2023/2184880","url":null,"abstract":"The purpose of this study is to explore the development depth of rock layer rupture and analyze the developmental regularity of mining floor in Dongsi mining area of Xinzhi Coal Mine. Two kinds of pressure water testing methods and numerical simulation are used to study the failure characteristics of the bottom plate of the working face in Dongsi mining area of Xinxian Coal Mine. The results show that the failure of working face bottom plate starts from a certain range in front of the working face. With the advance of working face, the failure depth of mining bottom plate increases continuously. At the same time, the failure range of mining roadway is slightly larger than the failure range of working face bottom plate due to the double disturbance of tunneling and mining. The pressure water test shows that the rupture depth occurs at 8.98-9.03 m. The numerical simulation results of floor failure depth show that its depth is about 8.7 m, which is basically consistent with the pressure water test. It provides a reference for the advanced preexploration of mining bottom plate failure in similar coal seam.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135733788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mingjiao Yan, Yang Yang, Zongliang Zhang, Chao Su, Tianfu Luo
This paper presents a PSBFEM approach that integrates the quadtree mesh generation technique based on digital images for solving seepage problems. The quantitative representation of the distribution of geometrical information and material parameters is achieved by utilizing the color intensity of each pixel, which can then be applied to seepage analysis. The presented method addresses the issue of hanging nodes by treating them as nodes of a polygonal element. We validate the proposed technique by solving three benchmark seepage problems. Results show that the image-based domain can be automatically discretized using a quadtree decomposition of the images. Furthermore, the computational efficiency and precision of the PSBFEM surpass that of the standard FEM. Therefore, the proposed technique allows for the convenient automatic discretization of the domain using pixel meshes to solve seepage problems in engineering applications.
{"title":"A PSBFEM Approach for Solving Seepage Problems Based on the Pixel Quadtree Mesh","authors":"Mingjiao Yan, Yang Yang, Zongliang Zhang, Chao Su, Tianfu Luo","doi":"10.1155/2023/9092488","DOIUrl":"https://doi.org/10.1155/2023/9092488","url":null,"abstract":"This paper presents a PSBFEM approach that integrates the quadtree mesh generation technique based on digital images for solving seepage problems. The quantitative representation of the distribution of geometrical information and material parameters is achieved by utilizing the color intensity of each pixel, which can then be applied to seepage analysis. The presented method addresses the issue of hanging nodes by treating them as nodes of a polygonal element. We validate the proposed technique by solving three benchmark seepage problems. Results show that the image-based domain can be automatically discretized using a quadtree decomposition of the images. Furthermore, the computational efficiency and precision of the PSBFEM surpass that of the standard FEM. Therefore, the proposed technique allows for the convenient automatic discretization of the domain using pixel meshes to solve seepage problems in engineering applications.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136107318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Due to the lack of drilling data and poor quality of seismic data in deep-water offshore areas, conventional methods cannot effectively predict the total organic carbon (TOC) content. In this paper, the BP neural network method is used to predict the TOC of the strata overlying the target layer, which adds to the TOC information in the study area. Then, the highest TOC value of the strata overlying the target layer is used to select the most sensitive seismic attributes. Finally, the sensitive seismic attributes are used to evaluate the source rocks with no or few wells. A set of TOC prediction technology flows is established for TOC combined with seismic attributes under the condition of no wells and few wells in deep-water areas. The application example shows the reliability of TOC prediction by this technical process, and the study has a certain reference significance for the evaluation of hydrocarbon source rocks in offshore deep water.
{"title":"Source Rock Evaluation of Hydrocarbons in Deep-Water Offshore Areas Based on a BP Neural Network","authors":"Jizhong Wu, Ying Shi, Qianqian Yang, Yanan Wang","doi":"10.1155/2023/4803616","DOIUrl":"https://doi.org/10.1155/2023/4803616","url":null,"abstract":"Due to the lack of drilling data and poor quality of seismic data in deep-water offshore areas, conventional methods cannot effectively predict the total organic carbon (TOC) content. In this paper, the BP neural network method is used to predict the TOC of the strata overlying the target layer, which adds to the TOC information in the study area. Then, the highest TOC value of the strata overlying the target layer is used to select the most sensitive seismic attributes. Finally, the sensitive seismic attributes are used to evaluate the source rocks with no or few wells. A set of TOC prediction technology flows is established for TOC combined with seismic attributes under the condition of no wells and few wells in deep-water areas. The application example shows the reliability of TOC prediction by this technical process, and the study has a certain reference significance for the evaluation of hydrocarbon source rocks in offshore deep water.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136107321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sandy dolomite, being a soluble rock, is prone to dissolution and erosion caused by groundwater, leading to the formation of underground caves and fractures. This may result in geological disasters such as ground subsidence and collapse. In this paper, the changes and mechanical properties of black sandy dolomite after hydrochemistry are studied. A semi-immersion test with different concentrations of iron sulfate solution was carried out to simulate the water-rock interaction in different water environments. After that, scanning electron microscope (SEM) results could reflect the dissolution and pore development of rock by the effect of water-rock interaction from the microscopic. Water-rock interaction enlarges cracks in rocks and dissolves pyrite, carbonate minerals, and other components, reducing the cementation between particles. The change in the mechanical properties of black sandy dolomite under water-rock chemical interaction was revealed by uniaxial compression test. The mechanical properties of the samples exhibit varying degrees of deterioration, with strain increased ranging from 4.96 to 29.58%. The brittleness index modified (BIM) values for each sample ranged from 5.20 to 6.20%, all of which are larger than 4.70% in the natural state.
{"title":"Degradation Characteristics and Mechanism of Black Sandy Dolomite with Fluid Added in a Mechanical Test","authors":"Xin Liao, Qi Xu, S. Ling, Angran Tian, Q. Tang","doi":"10.1155/2023/6197047","DOIUrl":"https://doi.org/10.1155/2023/6197047","url":null,"abstract":"Sandy dolomite, being a soluble rock, is prone to dissolution and erosion caused by groundwater, leading to the formation of underground caves and fractures. This may result in geological disasters such as ground subsidence and collapse. In this paper, the changes and mechanical properties of black sandy dolomite after hydrochemistry are studied. A semi-immersion test with different concentrations of iron sulfate solution was carried out to simulate the water-rock interaction in different water environments. After that, scanning electron microscope (SEM) results could reflect the dissolution and pore development of rock by the effect of water-rock interaction from the microscopic. Water-rock interaction enlarges cracks in rocks and dissolves pyrite, carbonate minerals, and other components, reducing the cementation between particles. The change in the mechanical properties of black sandy dolomite under water-rock chemical interaction was revealed by uniaxial compression test. The mechanical properties of the samples exhibit varying degrees of deterioration, with strain increased ranging from 4.96 to 29.58%. The brittleness index modified (BIM) values for each sample ranged from 5.20 to 6.20%, all of which are larger than 4.70% in the natural state.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41687002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Mouzong, Inoussah Moungnutou Mfetoum, S. K. Ngoh, Prosper Gopdjim Noumo, J. Tamba
Cameroon is a country in Central Africa that relies heavily on hydropower, fossil fuels, solar, and biomass for its energy needs. However, the unstable and intermittent nature of these energy sources makes them unreliable, and there is a pressing need for a more secure and sustainable energy supply. Geothermal energy, which is abundant in Cameroon due to its favorable geological characteristics, has not been fully explored as a potential energy source. This study is aimed at providing a comprehensive review of the current status and future prospects of geothermal energy in Cameroon, based on publications related to geothermal energy in Cameroon, geological, and geophysical studies. The objectives of this study are to analyze the existing literature on geothermal energy in Cameroon, to identify the challenges and opportunities associated with geothermal energy development, and to make recommendations for future research and policy decisions. The results indicate that geothermal energy in Cameroon is still in its infancy, with limited research and development in the field. However, the country has geothermal potential, particularly in the Adamawa and Cameroon volcanic line (CVL) areas. The review highlights the challenges and barriers to geothermal energy development in Cameroon, including limited financial resources, technical expertise, and regulatory frameworks. The findings of this study suggest that Cameroon has significant potential for geothermal energy development, and that further exploration and investment in this area could contribute significantly to a more secure and sustainable energy supply in the country.
{"title":"Current Status, Future Prospects, and the Need for Geothermal Energy Exploration in Cameroon: Comprehensive Review","authors":"M. Mouzong, Inoussah Moungnutou Mfetoum, S. K. Ngoh, Prosper Gopdjim Noumo, J. Tamba","doi":"10.1155/2023/6168519","DOIUrl":"https://doi.org/10.1155/2023/6168519","url":null,"abstract":"Cameroon is a country in Central Africa that relies heavily on hydropower, fossil fuels, solar, and biomass for its energy needs. However, the unstable and intermittent nature of these energy sources makes them unreliable, and there is a pressing need for a more secure and sustainable energy supply. Geothermal energy, which is abundant in Cameroon due to its favorable geological characteristics, has not been fully explored as a potential energy source. This study is aimed at providing a comprehensive review of the current status and future prospects of geothermal energy in Cameroon, based on publications related to geothermal energy in Cameroon, geological, and geophysical studies. The objectives of this study are to analyze the existing literature on geothermal energy in Cameroon, to identify the challenges and opportunities associated with geothermal energy development, and to make recommendations for future research and policy decisions. The results indicate that geothermal energy in Cameroon is still in its infancy, with limited research and development in the field. However, the country has geothermal potential, particularly in the Adamawa and Cameroon volcanic line (CVL) areas. The review highlights the challenges and barriers to geothermal energy development in Cameroon, including limited financial resources, technical expertise, and regulatory frameworks. The findings of this study suggest that Cameroon has significant potential for geothermal energy development, and that further exploration and investment in this area could contribute significantly to a more secure and sustainable energy supply in the country.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45545888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Significant amounts of unconventional oil and gas resources have been discovered in the Yanchang Formation of Ordos Basin. Shale layers deposited in Chang 7 member (divided into Chang 7-2 submember (C7-2SM) and Chang 7-3 submember (C7-3SM) and Chang 9 member (C9M)) are the main source rocks. Based on the comparison of mineralogical and geochemical characteristics, it is concluded that (1) in terms of mineralogical characteristics, the C7-3SM shale possesses the largest content of illite/smectite mixed layer and reducing minerals and the least quantity of quartz. The C9M shale shows the highest percentage of quartz and illite and the least amount of K-feldspar and Kaolinite. In C7-2SM and C9M shale, amorphous silica surrounded tightly by clay minerals is easily observed by the scanning electron microscopy. Besides the drilling orientation, the small content of quartz contributed to the lowest porosity for the C7-3SM shale. (2) In terms of geochemical characteristics, the C7-3SM shale exhibits high productivity due to type II1 kerogen. The organic matter in the C7-2SM and C9M shale contains mainly type II2 and possibly type III kerogen. The C9M shale exhibits the highest organic thermal maturity. The C7-3SM shale was formed in a relatively higher salinity of sedimentary water.
{"title":"The Exquisite Comparison of Shale Mineralogical-Geochemical Characteristics between Chang 7 Member and Chang 9 Member in Yanchang Formation, Ordos Basin","authors":"Wang Zhang, Xinping Liang, Peng Li, Guoheng Liu","doi":"10.1155/2023/5039604","DOIUrl":"https://doi.org/10.1155/2023/5039604","url":null,"abstract":"Significant amounts of unconventional oil and gas resources have been discovered in the Yanchang Formation of Ordos Basin. Shale layers deposited in Chang 7 member (divided into Chang 7-2 submember (C7-2SM) and Chang 7-3 submember (C7-3SM) and Chang 9 member (C9M)) are the main source rocks. Based on the comparison of mineralogical and geochemical characteristics, it is concluded that (1) in terms of mineralogical characteristics, the C7-3SM shale possesses the largest content of illite/smectite mixed layer and reducing minerals and the least quantity of quartz. The C9M shale shows the highest percentage of quartz and illite and the least amount of K-feldspar and Kaolinite. In C7-2SM and C9M shale, amorphous silica surrounded tightly by clay minerals is easily observed by the scanning electron microscopy. Besides the drilling orientation, the small content of quartz contributed to the lowest porosity for the C7-3SM shale. (2) In terms of geochemical characteristics, the C7-3SM shale exhibits high productivity due to type II1 kerogen. The organic matter in the C7-2SM and C9M shale contains mainly type II2 and possibly type III kerogen. The C9M shale exhibits the highest organic thermal maturity. The C7-3SM shale was formed in a relatively higher salinity of sedimentary water.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46978584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chunlong Wang, Hongkai Zhao, Li Cheng, Guilin Li, Yuyun Fan, Mingwei Jiang, Yingjie Hao, Kun Shao
As the heat hazard problem in the deep mine becomes more prominent, it is difficult to alleviate the high-temperature problem by increasing the air supply and adjusting the ventilation mode alone. In order to solve the issue of heat damage in the Linglong Gold Mine, a cooling system based on water source heat pump technology and utilizing the return air system to exhaust heat was constructed, and each system was rationally arranged in conjunction with the mine’s actual conditions. The reasonable critical threshold of cooling system parameters is then determined by numerical simulation and field application verification. The results indicate that the closed cycle adopted by the cooling system can effectively solve the problem of groundwater shortage. The heat can be discharged directly to the return air shaft to prevent the impact of secondary heat hazards. The temperature near the working face can be reduced from 35°C to below 28°C. This system effectively resolves the issues of water shortage, heat release, and cold transfer in the water source heat pump technology and provides a reference for the application of other mines.
{"title":"Layout and Parameter Analysis of the Cooling System with Mine Water as Cold Source in Linglong Gold Mine","authors":"Chunlong Wang, Hongkai Zhao, Li Cheng, Guilin Li, Yuyun Fan, Mingwei Jiang, Yingjie Hao, Kun Shao","doi":"10.1155/2023/4791411","DOIUrl":"https://doi.org/10.1155/2023/4791411","url":null,"abstract":"As the heat hazard problem in the deep mine becomes more prominent, it is difficult to alleviate the high-temperature problem by increasing the air supply and adjusting the ventilation mode alone. In order to solve the issue of heat damage in the Linglong Gold Mine, a cooling system based on water source heat pump technology and utilizing the return air system to exhaust heat was constructed, and each system was rationally arranged in conjunction with the mine’s actual conditions. The reasonable critical threshold of cooling system parameters is then determined by numerical simulation and field application verification. The results indicate that the closed cycle adopted by the cooling system can effectively solve the problem of groundwater shortage. The heat can be discharged directly to the return air shaft to prevent the impact of secondary heat hazards. The temperature near the working face can be reduced from 35°C to below 28°C. This system effectively resolves the issues of water shortage, heat release, and cold transfer in the water source heat pump technology and provides a reference for the application of other mines.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41622278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yu‐Ling Bo, Z. Tao, Zheng Kexun, S. Zuo, Han Xiao, Senlin Wang, Shiwan Chen
An enclosed karst depression, a typical natural negative terrain, has the advantage of less engineering excavation when constructing a reservoir. In this study, the enclosed karst depression and its range identification technique have been developed. What is more, the geometric parameters and spatial distribution of enclosed karst depressions in Anlong County, Guizhou Province of China, have also been analyzed. Results show that (1) the focus statistic method and local terrain contour tree model were developed to identify enclosed karst depression and its range using regular grid DEM data with 12.5 m spatial resolution, which has been applied to enclosed karst depression identification in Anlong County. (2) 7262 independent and nested depressions with an average density of 3.7/km2 were identified by using the proposed method. The effectiveness and reliability of the proposed model have been verified through comparative analysis and visual recognition comparison. (3) High-density depression areas (5.6 depressions/km2), medium-density depression areas (2.9 depressions/km2), and low-density depression areas (1.1 depressions/km2) were well classified through kernel density analysis. (4) The geometric parameters of enclosed karst depressions (area, perimeter, circularity, depth, elevation, slope, and volume) were all analyzed in the study area. In addition, an indicator called DCK (depression is caused by karstification) was proposed to evaluate the dissolution degree and karstification stage of the enclosed karst depression. Based on the DCK, we determined that around 2.7% of depressions were identified as middle-stage and suitable for reservoir construction with enough volume and good slope stability. The idea and method in this research could provide a technological support for the engineering utilization of enclosed karst depressions.
{"title":"Enclosed Karst Depression Identification and Analysis for the Pumped Storage Power Station Reservoir Construction Using DEM","authors":"Yu‐Ling Bo, Z. Tao, Zheng Kexun, S. Zuo, Han Xiao, Senlin Wang, Shiwan Chen","doi":"10.1155/2023/4794665","DOIUrl":"https://doi.org/10.1155/2023/4794665","url":null,"abstract":"An enclosed karst depression, a typical natural negative terrain, has the advantage of less engineering excavation when constructing a reservoir. In this study, the enclosed karst depression and its range identification technique have been developed. What is more, the geometric parameters and spatial distribution of enclosed karst depressions in Anlong County, Guizhou Province of China, have also been analyzed. Results show that (1) the focus statistic method and local terrain contour tree model were developed to identify enclosed karst depression and its range using regular grid DEM data with 12.5 m spatial resolution, which has been applied to enclosed karst depression identification in Anlong County. (2) 7262 independent and nested depressions with an average density of 3.7/km2 were identified by using the proposed method. The effectiveness and reliability of the proposed model have been verified through comparative analysis and visual recognition comparison. (3) High-density depression areas (5.6 depressions/km2), medium-density depression areas (2.9 depressions/km2), and low-density depression areas (1.1 depressions/km2) were well classified through kernel density analysis. (4) The geometric parameters of enclosed karst depressions (area, perimeter, circularity, depth, elevation, slope, and volume) were all analyzed in the study area. In addition, an indicator called DCK (depression is caused by karstification) was proposed to evaluate the dissolution degree and karstification stage of the enclosed karst depression. Based on the DCK, we determined that around 2.7% of depressions were identified as middle-stage and suitable for reservoir construction with enough volume and good slope stability. The idea and method in this research could provide a technological support for the engineering utilization of enclosed karst depressions.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46616683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Boise sandstone has a variety of grain diameter, and the heterogeneity makes it difficult to characterize. In this paper, a model of viscous squirt is used to simulate velocity and attenuation of ultrasonic P-wave in the sandstone saturated with water. Phase velocity yielding from the model is fitted against the velocity measured at frequency of 500 kHz, which determinates the quality factor due to viscous squirt ( Q p s ) as a function of frequency. The resulting Q p s appears to be 14.64 at frequency of 0.8 MHz. With the use of the measured total quality factor ( Q p ) of 6.9 at 0.8 MHz, the dry quality factor ( Q p d ) appears to be 13.0 at 0.8 MHz. The resulting dimension of the rock unit is 0.150 multiplied by 0.140 mm, pretty consistent with the mean grain diameter of 0.150 mm. The relative first and second porosities are ascertained to be 0.976 and 0.024, respectively, and the aperture distance of the second porosity is 0.84 μm. Nonetheless, the model represents analytical continuation of small rock samples. Consequently, seismic attenuation predicted by the model is far smaller than field observation. The discrepancy shows that strong seismic attenuation in the field is associated with a scale much larger than pore scale.
博伊西砂岩粒度多样，非均质性使其难以表征。本文采用粘性喷射模型模拟了超声波纵波在含水砂岩中的传播速度和衰减。由模型得到的相速度与频率为500khz的测量速度拟合，确定了由于粘性喷射引起的质量因子(Q p s)作为频率的函数。在0.8 MHz频率下得到的Q p s为14.64。在0.8 MHz时，使用测量到的总质量因子(Q p)为6.9，则在0.8 MHz时，干质量因子(Q p d)为13.0。得到的岩石单元尺寸为0.150 × 0.140 mm，与平均粒径0.150 mm相当一致。确定第一孔隙度和第二孔隙度的相对孔隙度分别为0.976和0.024，第二孔隙度的孔径距离为0.84 μm。尽管如此，该模型代表了小岩石样品的分析延续。因此，模型预测的地震衰减值远小于现场观测值。这种差异表明，强地震衰减与比孔隙尺度大得多的尺度有关。
{"title":"Ultrasonic P-Wave to Acquire Parameters of Boise Sandstone","authors":"Guangquan Li, Kui Liu, Xiang Li","doi":"10.1155/2023/7360208","DOIUrl":"https://doi.org/10.1155/2023/7360208","url":null,"abstract":"Boise sandstone has a variety of grain diameter, and the heterogeneity makes it difficult to characterize. In this paper, a model of viscous squirt is used to simulate velocity and attenuation of ultrasonic P-wave in the sandstone saturated with water. Phase velocity yielding from the model is fitted against the velocity measured at frequency of 500 kHz, which determinates the quality factor due to viscous squirt (\u0000 \u0000 \u0000 \u0000 Q\u0000 \u0000 \u0000 p\u0000 s\u0000 \u0000 \u0000 \u0000 ) as a function of frequency. The resulting \u0000 \u0000 \u0000 \u0000 Q\u0000 \u0000 \u0000 p\u0000 s\u0000 \u0000 \u0000 \u0000 appears to be 14.64 at frequency of 0.8 MHz. With the use of the measured total quality factor (\u0000 \u0000 \u0000 \u0000 Q\u0000 \u0000 \u0000 p\u0000 \u0000 \u0000 \u0000 ) of 6.9 at 0.8 MHz, the dry quality factor (\u0000 \u0000 \u0000 \u0000 Q\u0000 \u0000 \u0000 p\u0000 d\u0000 \u0000 \u0000 \u0000 ) appears to be 13.0 at 0.8 MHz. The resulting dimension of the rock unit is 0.150 multiplied by 0.140 mm, pretty consistent with the mean grain diameter of 0.150 mm. The relative first and second porosities are ascertained to be 0.976 and 0.024, respectively, and the aperture distance of the second porosity is 0.84 μm. Nonetheless, the model represents analytical continuation of small rock samples. Consequently, seismic attenuation predicted by the model is far smaller than field observation. The discrepancy shows that strong seismic attenuation in the field is associated with a scale much larger than pore scale.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46580932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The bedding structure of shale is generated during the deposition and formation, which results in shales with prominent anisotropic characteristics. It depends on stability, control of oil and gas storage, and deep exploitation. In addition, the mechanical and permeability parts of bedding shale are very complex when it is under deep underground space with coupled high stress and high seepage. In this study, the black bedding shale was used as the research object, and a series of triaxial shear-seepage coupling tests were carried out. Firstly, the triaxial shear stress-shear strain curves and permeability-shear stress curves of different bedding shales under other triaxial shear-seepage coupling conditions were obtained. Secondly, the failure characteristics and shear deformation characteristics of shale under the shear-seepage coupling effect were explored. The shear stress threshold and permeability evolution law at each stage of shear failure were discussed. Thirdly, the shear strength, failure mode, and mechanism parameters of the black bedding shale under different normal stress and seepage pressure were studied. Fourthly, the linear M-C criterion, Ramamurthy criterion, and Hoek-Brown criterion characterize the variation of damage strength of shale with bedding orientation under triaxial shear-seepage coupling. Those results provide an experimental basis for exploring the anisotropic mechanical characteristics and failure mechanism of bedding shale under shear-seepage coupling.
{"title":"Experimental Study on Permeability and Deformation Characteristics of Bedding Shale under Triaxial Shear-Seepage Coupling","authors":"Zhinan Lin, Shihong Feng, Jia-quan Wang, Qiang Zhang, Haifeng Long, Guangming Chen","doi":"10.1155/2023/6314590","DOIUrl":"https://doi.org/10.1155/2023/6314590","url":null,"abstract":"The bedding structure of shale is generated during the deposition and formation, which results in shales with prominent anisotropic characteristics. It depends on stability, control of oil and gas storage, and deep exploitation. In addition, the mechanical and permeability parts of bedding shale are very complex when it is under deep underground space with coupled high stress and high seepage. In this study, the black bedding shale was used as the research object, and a series of triaxial shear-seepage coupling tests were carried out. Firstly, the triaxial shear stress-shear strain curves and permeability-shear stress curves of different bedding shales under other triaxial shear-seepage coupling conditions were obtained. Secondly, the failure characteristics and shear deformation characteristics of shale under the shear-seepage coupling effect were explored. The shear stress threshold and permeability evolution law at each stage of shear failure were discussed. Thirdly, the shear strength, failure mode, and mechanism parameters of the black bedding shale under different normal stress and seepage pressure were studied. Fourthly, the linear M-C criterion, Ramamurthy criterion, and Hoek-Brown criterion characterize the variation of damage strength of shale with bedding orientation under triaxial shear-seepage coupling. Those results provide an experimental basis for exploring the anisotropic mechanical characteristics and failure mechanism of bedding shale under shear-seepage coupling.","PeriodicalId":12512,"journal":{"name":"Geofluids","volume":" ","pages":""},"PeriodicalIF":1.7,"publicationDate":"2023-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44975584","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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