Yunhui Zhang, Xiangbo Hu, Huan Luo, Yang Liu, Rongwen Yao, J. Duo, Xiao Li, Xun Huang
Water inrush is one of the most serious phenomena threatening the safety of tunnel construction. The West Qinling 1# tunnel, as the major section of the Bailong River diversion project, traverses a complicated karst area and would be faced with a water inrush disaster. Based on geological and hydrogeological conditions, the Finite element subsurface flow system software is used to simulate and predict the development of the natural seepage field and dredging construction conditions of the seepage field on the West Qinling 1# tunnel area. The prediction results show that the groundwater level will drop up to 113.9 m under dredging construction conditions, with an impact radius of up to 11.5 km. Seepage field evolution and water influx were simulated under two conditions of construction plugging construction, respectively. The prediction results show that the groundwater level in the middle part of tunnel 1# is 112.68 m depth without blocking condition with an influence range of 10.5 km. The maximum water volume per unit length of the karst cave increases to 4.32 m3/d·m. In the plugging condition, the influencing scope does not significantly reduce, but the extent of the impact is greatly weakened. The groundwater level generally dropped at 10–25 m depth and the karst cave section unit length of the maximum water volume of 0.83 m3/d·m in the rainy season. The achievements of this study would provide a vital reference for the prevention of water inrush in karst tunnel construction.
{"title":"Identifying the Change of Seepage Field in Karst Aquifer under Tunnel Engineering: Insight from FEFLOW Modeling","authors":"Yunhui Zhang, Xiangbo Hu, Huan Luo, Yang Liu, Rongwen Yao, J. Duo, Xiao Li, Xun Huang","doi":"10.2113/2021/6044574","DOIUrl":"https://doi.org/10.2113/2021/6044574","url":null,"abstract":"\u0000 Water inrush is one of the most serious phenomena threatening the safety of tunnel construction. The West Qinling 1# tunnel, as the major section of the Bailong River diversion project, traverses a complicated karst area and would be faced with a water inrush disaster. Based on geological and hydrogeological conditions, the Finite element subsurface flow system software is used to simulate and predict the development of the natural seepage field and dredging construction conditions of the seepage field on the West Qinling 1# tunnel area. The prediction results show that the groundwater level will drop up to 113.9 m under dredging construction conditions, with an impact radius of up to 11.5 km. Seepage field evolution and water influx were simulated under two conditions of construction plugging construction, respectively. The prediction results show that the groundwater level in the middle part of tunnel 1# is 112.68 m depth without blocking condition with an influence range of 10.5 km. The maximum water volume per unit length of the karst cave increases to 4.32 m3/d·m. In the plugging condition, the influencing scope does not significantly reduce, but the extent of the impact is greatly weakened. The groundwater level generally dropped at 10–25 m depth and the karst cave section unit length of the maximum water volume of 0.83 m3/d·m in the rainy season. The achievements of this study would provide a vital reference for the prevention of water inrush in karst tunnel construction.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"6 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86271454","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}
Hydraulic fracture propagation has a great influence on reservoir reconstruction in shale gas exploitation. The study on mechanism of hydraulic fracture propagation is important. Based on the fluid-solid coupling theory, the propagation criterion under hydraulic pressure of shale is deduced in this paper. In combination with large-scale true triaxial experiment and numerical simulation, the law of hydraulic fracture propagation is researched, and the mechanism of hydraulic fracture propagation is obtained. The results show that shale will produce tensile failure and shear failure under the interaction of water pressure and ground stress. Acoustic emission monitoring data show that the initiation of microfracture is related to water pressure. When the fracture occurs, the number of acoustic emission events increases, and the water pressure drops sharply. Tensile failure occurs mainly at the crack tip, while shear failure occurs mainly at the weak structural plane. When bedding is encountered, hydraulic fracture will be diverted and spread along the bedding. If the strength of the cement inside the bedding is high, the hydraulic fracture passes directly through the weak structural plane. In this paper, the mechanism of shale hydraulic fracture propagation is studied, which has a certain theoretical and practical significance for shale gas fracturing effect evaluation and reservoir stimulation.
{"title":"Fluid-Solid Coupling Mechanism of Shale Hydraulic Fracture Propagation Based on True Triaxial Test and Numerical Analysis","authors":"Bohu Zhang, Yao Hu, Xinxin Hu, Qian Xu","doi":"10.2113/2022/5085244","DOIUrl":"https://doi.org/10.2113/2022/5085244","url":null,"abstract":"\u0000 Hydraulic fracture propagation has a great influence on reservoir reconstruction in shale gas exploitation. The study on mechanism of hydraulic fracture propagation is important. Based on the fluid-solid coupling theory, the propagation criterion under hydraulic pressure of shale is deduced in this paper. In combination with large-scale true triaxial experiment and numerical simulation, the law of hydraulic fracture propagation is researched, and the mechanism of hydraulic fracture propagation is obtained. The results show that shale will produce tensile failure and shear failure under the interaction of water pressure and ground stress. Acoustic emission monitoring data show that the initiation of microfracture is related to water pressure. When the fracture occurs, the number of acoustic emission events increases, and the water pressure drops sharply. Tensile failure occurs mainly at the crack tip, while shear failure occurs mainly at the weak structural plane. When bedding is encountered, hydraulic fracture will be diverted and spread along the bedding. If the strength of the cement inside the bedding is high, the hydraulic fracture passes directly through the weak structural plane. In this paper, the mechanism of shale hydraulic fracture propagation is studied, which has a certain theoretical and practical significance for shale gas fracturing effect evaluation and reservoir stimulation.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"195 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73687849","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}
Xiaoyan Li, Baocheng Shi, Jianpeng Pan, X. Zhang, Kai Liu, Guofa Ji, Yindi Zhang
Oxygen-reduced air flooding (ORAF) is an important efficient development means for tight and low permeability reservoirs because of its low cost, low risk, and ability to penetrate into voids and substrates. However, the critical value of oxygen-reduced, which can take into account the cost and corrosion protection requirements, is uncertain. Therefore, the corrosion behavior of N80, J55, and 3Cr steels under simulated high pressure (30 MPa) gas injection with different oxygen content (1%–12% vol.) was studied by weight loss method and Ultra-Depth Three-Dimensional Microscope. Under this oxygen content, the corrosion behavior of N80, J55, and 3Cr steels under different total pressure (20–35 MPa), temperature (25℃–70℃), and coexistence of gas and water was further studied. The results show that under the condition of high temperature and high-pressure drying, when the oxygen content in the oxygen-reduced air is reduced to 5%, all three kinds of steels belong to slight corrosion (<0.025 mm/a), and the oxygen-reduced cost can still be kept at a low level. In addition, under the condition of 5% oxygen content, when the corrosion medium of the wellbore is only deoxidized gas, the corrosion is slight, so N80 steel at a lower cost can be used. However, when the wellbore contains liquid, the corrosion is serious, and anticorrosion measures need to be taken. This study can provide certain data support for the selection of oxygen content and the corrosion protection of gas-injection wells shaft in the process of high-pressure gas injection by ORAF.
{"title":"Study on the Oxygen Content of Oxygen-Reducing Air Flooding Based on Anticorrosion Considerations","authors":"Xiaoyan Li, Baocheng Shi, Jianpeng Pan, X. Zhang, Kai Liu, Guofa Ji, Yindi Zhang","doi":"10.2113/2022/6264272","DOIUrl":"https://doi.org/10.2113/2022/6264272","url":null,"abstract":"\u0000 Oxygen-reduced air flooding (ORAF) is an important efficient development means for tight and low permeability reservoirs because of its low cost, low risk, and ability to penetrate into voids and substrates. However, the critical value of oxygen-reduced, which can take into account the cost and corrosion protection requirements, is uncertain. Therefore, the corrosion behavior of N80, J55, and 3Cr steels under simulated high pressure (30 MPa) gas injection with different oxygen content (1%–12% vol.) was studied by weight loss method and Ultra-Depth Three-Dimensional Microscope. Under this oxygen content, the corrosion behavior of N80, J55, and 3Cr steels under different total pressure (20–35 MPa), temperature (25℃–70℃), and coexistence of gas and water was further studied. The results show that under the condition of high temperature and high-pressure drying, when the oxygen content in the oxygen-reduced air is reduced to 5%, all three kinds of steels belong to slight corrosion (<0.025 mm/a), and the oxygen-reduced cost can still be kept at a low level. In addition, under the condition of 5% oxygen content, when the corrosion medium of the wellbore is only deoxidized gas, the corrosion is slight, so N80 steel at a lower cost can be used. However, when the wellbore contains liquid, the corrosion is serious, and anticorrosion measures need to be taken. This study can provide certain data support for the selection of oxygen content and the corrosion protection of gas-injection wells shaft in the process of high-pressure gas injection by ORAF.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"42 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77639039","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}
This pilot study is founded on an exhaustive investigation of representative and well-documented cases (120) of carbonate systems during the Phanerozoic. We investigated the coupling between geodynamic settings and geometry, physiography, and stratigraphic architecture of carbonate platforms. The objective is to identify and quantify the impact of geodynamic controls on carbonate platforms and possible global trends during the Phanerozoic. Carbonate platforms are characterized in terms of geometry, stratigraphic architecture, time duration, preservation rate, progradation and rates of progradation, platform type, and thickness. Geodynamic parameters are characterized in terms of basin physiography, basement depth and type, tectonic setting, and subsidence origin. Relationships between carbonate parameters and geodynamic characteristics are investigated, leading to nine models of Geodynamic Carbonate Platforms. Passive margin is the most favorable geodynamic setting for the development of carbonate platforms in three dimensions. The continental crust hosts most of the carbonate platforms independently of time and geodynamic settings. Carbonate platforms developed above the exhumed mantle or oceanic crust (volcano) are the exception or very small and isolated. Global trends during the Phanerozoic of carbonate platform lateral extend, progradation, or thickness are tentatively interpreted in relation to geodynamic and eustatic parameters. The concept of spatial intersection between geodynamic and climatic windows favorable to carbonate platforms is introduced with its possible retroaction to the global carbon cycle.
{"title":"Global Geodynamic Control on Phanerozoic Marine Carbonates Sedimentary Systems","authors":"Tassy Aurélie, Borgomano Jean, Leonide Philippe, Hairabian Alex, Lanteaume Cyprien, Michel Julien","doi":"10.2113/2023/9689299","DOIUrl":"https://doi.org/10.2113/2023/9689299","url":null,"abstract":"\u0000 This pilot study is founded on an exhaustive investigation of representative and well-documented cases (120) of carbonate systems during the Phanerozoic. We investigated the coupling between geodynamic settings and geometry, physiography, and stratigraphic architecture of carbonate platforms. The objective is to identify and quantify the impact of geodynamic controls on carbonate platforms and possible global trends during the Phanerozoic. Carbonate platforms are characterized in terms of geometry, stratigraphic architecture, time duration, preservation rate, progradation and rates of progradation, platform type, and thickness. Geodynamic parameters are characterized in terms of basin physiography, basement depth and type, tectonic setting, and subsidence origin. Relationships between carbonate parameters and geodynamic characteristics are investigated, leading to nine models of Geodynamic Carbonate Platforms. Passive margin is the most favorable geodynamic setting for the development of carbonate platforms in three dimensions. The continental crust hosts most of the carbonate platforms independently of time and geodynamic settings. Carbonate platforms developed above the exhumed mantle or oceanic crust (volcano) are the exception or very small and isolated. Global trends during the Phanerozoic of carbonate platform lateral extend, progradation, or thickness are tentatively interpreted in relation to geodynamic and eustatic parameters. The concept of spatial intersection between geodynamic and climatic windows favorable to carbonate platforms is introduced with its possible retroaction to the global carbon cycle.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"94 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79535361","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}
Kezhu Chen, Tianbin Li, Meiben Gao, Chun-chi Ma, Y. Zhang
Rockburst plays a serious threat to personnel and equipment during underground engineering construction. The study of the rockburst mechanism is helpful to its prediction and prevention. Based on the characteristic analysis of a large number of rockburst cases, Li et al. proposed three stress-type and three stress-structural rockbursts and obtained the geological characteristics and occurrence criteria of these rockbursts, but the evolution process of rockbursts is still unclear. Based on the continuous-discontinuous element method, the characteristics of failure process, surrounding rock stress, motion, and energy of three stress-rockburst blocks are analyzed. The results show that rockburst failure generally goes through several stages, such as a few surfaces tensile failure, shallow shear failure, deep extension of tensile failure, shear failure communication, and rockburst occurrence. The total volume of rockburst blocks and the main distribution intervals of block diameters for different types of rockbursts are quite different, which are mainly affected by stress state and geological structure. The ejection velocity of the small block is always higher than that of the large block during the same one rockburst simulation, and the ejection velocity of the small block is from the surface. In the process of rockburst, not only the elastic strain energy is released but also the elastic strain energy is accumulated. The greater the rockburst intensity, the more the elastic strain energy is released, and the steeper the prepeak curve of elastic strain energy. The research results provide a reference for further understanding the mechanism of rockburst and lay a theoretical basis for the prevention and control of rockburst in underground engineering.
{"title":"Study on Stress-Type Rockburst Mechanism Based on Continuous-Discontinuous Element Method","authors":"Kezhu Chen, Tianbin Li, Meiben Gao, Chun-chi Ma, Y. Zhang","doi":"10.2113/2022/5668451","DOIUrl":"https://doi.org/10.2113/2022/5668451","url":null,"abstract":"\u0000 Rockburst plays a serious threat to personnel and equipment during underground engineering construction. The study of the rockburst mechanism is helpful to its prediction and prevention. Based on the characteristic analysis of a large number of rockburst cases, Li et al. proposed three stress-type and three stress-structural rockbursts and obtained the geological characteristics and occurrence criteria of these rockbursts, but the evolution process of rockbursts is still unclear. Based on the continuous-discontinuous element method, the characteristics of failure process, surrounding rock stress, motion, and energy of three stress-rockburst blocks are analyzed. The results show that rockburst failure generally goes through several stages, such as a few surfaces tensile failure, shallow shear failure, deep extension of tensile failure, shear failure communication, and rockburst occurrence. The total volume of rockburst blocks and the main distribution intervals of block diameters for different types of rockbursts are quite different, which are mainly affected by stress state and geological structure. The ejection velocity of the small block is always higher than that of the large block during the same one rockburst simulation, and the ejection velocity of the small block is from the surface. In the process of rockburst, not only the elastic strain energy is released but also the elastic strain energy is accumulated. The greater the rockburst intensity, the more the elastic strain energy is released, and the steeper the prepeak curve of elastic strain energy. The research results provide a reference for further understanding the mechanism of rockburst and lay a theoretical basis for the prevention and control of rockburst in underground engineering.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"27 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-05-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83374259","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}
In this study, the interfacial reaction method was used to modify the laponite particles using 3-glycidoxypropyltrimethoxysilane and octadecylamine, and the structure, morphology, and displacement performance tests of the modified particles were carried out. Elemental analysis, Fourier-transform infrared spectrometer, thermogravimetric analysis, and transmission electron microscopy are used to characterize the structure and morphology of the modified particles, and the results showed that laponite particles had been successfully modified. Results of the study indicated that Laponite®-based amphiphilic janus nanosheets (LAS) can accumulate at the interface, reduce the interfacial tension from 14.9 to 9.6 mN/m, and have a good emulsification effect for a long time. Second, the wettability alteration exhibited by LAS can change the wettability of the rock from oil-wet to water-wet. In addition, oil displacement experiments showed that LAS nanofluids can extract 11.6% at low concentration, which has a certain application potential.
{"title":"Preparation and Application of Laponite®-Based Amphiphilic Janus Nanosheets for Enhanced Oil Recovery","authors":"Xiu-rong Wang","doi":"10.2113/2022/2970640","DOIUrl":"https://doi.org/10.2113/2022/2970640","url":null,"abstract":"\u0000 In this study, the interfacial reaction method was used to modify the laponite particles using 3-glycidoxypropyltrimethoxysilane and octadecylamine, and the structure, morphology, and displacement performance tests of the modified particles were carried out. Elemental analysis, Fourier-transform infrared spectrometer, thermogravimetric analysis, and transmission electron microscopy are used to characterize the structure and morphology of the modified particles, and the results showed that laponite particles had been successfully modified. Results of the study indicated that Laponite®-based amphiphilic janus nanosheets (LAS) can accumulate at the interface, reduce the interfacial tension from 14.9 to 9.6 mN/m, and have a good emulsification effect for a long time. Second, the wettability alteration exhibited by LAS can change the wettability of the rock from oil-wet to water-wet. In addition, oil displacement experiments showed that LAS nanofluids can extract 11.6% at low concentration, which has a certain application potential.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"82 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89876167","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}
At present, there is no corresponding standard for the engineering application of rock acoustic emission technology. To better apply acoustic emission technology to engineering practice, in this paper, the acoustic emission characteristics of different rock samples of marble and granite under uniaxial compression were analyzed by indoor acoustic emission test, the factors affecting the acoustic emission characteristics of rocks are studied, and the failure mechanism and damage characteristics of rock are discussed. The research contents include analyzing the curve fitting relationship between the acoustic emission event rate, the number of events, the stress time, and study of the similarities and differences of acoustic emission characteristics of marble and granite; analysis of damage characteristics of marble and granite based on acoustic emission parameters; by analyzing the relationship between the Felicity ratio of different rocks and the stress level during cyclic loading, the applicability of studying the Kaiser and Felicity effects of rocks; variation of acoustic emission event rate and rock peak intensity under different loading methods and loading rates. The results show that the acoustic emission of marble and granite has experienced the initial compaction zone, the rising zone, the peak zone, and the falling zone, and the two kinds of rocks have different acoustic emission phenomena in different stages, and the duration of each stage is also different; before the instability of the two kinds of rocks, there is a quiet period of acoustic emission, and the higher the rock strength, the longer the duration of this quiet period, which means that the calm period can be used as a precursor feature of rock mass instability for disaster prediction; during the cyclic loading process of rock, the damage development law is divided into three stages: initial stage, stable stage, and instability stage. When the Kaiser effect did not appear for the two rock stresses before 20%, between 20% and 70% of the peak strength, the Kaiser effect is obvious. When the stress exceeds 80% of the peak value, the Kaiser effect fails, and the Felicity effect appears; the variation of the loading rate affects the variation of the acoustic emission event rate, and the increase of the loading rate leads to aggravated rock damage. The theoretical stress-strain curve can reasonably reflect the actual stress-strain characteristics of rock by combining the number of acoustic emission events with the rock damage model. The results are consistent with the acoustic emission test, which verifies the inevitable relationship between acoustic emission and damage to the rock.
{"title":"Research on the Characteristics of Acoustic Emission Activities of Granite and Marble under Different Loading Methods","authors":"Yongshuai Sun, Fei Yu, Jianguo Lv","doi":"10.2113/2023/2773795","DOIUrl":"https://doi.org/10.2113/2023/2773795","url":null,"abstract":"\u0000 At present, there is no corresponding standard for the engineering application of rock acoustic emission technology. To better apply acoustic emission technology to engineering practice, in this paper, the acoustic emission characteristics of different rock samples of marble and granite under uniaxial compression were analyzed by indoor acoustic emission test, the factors affecting the acoustic emission characteristics of rocks are studied, and the failure mechanism and damage characteristics of rock are discussed. The research contents include analyzing the curve fitting relationship between the acoustic emission event rate, the number of events, the stress time, and study of the similarities and differences of acoustic emission characteristics of marble and granite; analysis of damage characteristics of marble and granite based on acoustic emission parameters; by analyzing the relationship between the Felicity ratio of different rocks and the stress level during cyclic loading, the applicability of studying the Kaiser and Felicity effects of rocks; variation of acoustic emission event rate and rock peak intensity under different loading methods and loading rates. The results show that the acoustic emission of marble and granite has experienced the initial compaction zone, the rising zone, the peak zone, and the falling zone, and the two kinds of rocks have different acoustic emission phenomena in different stages, and the duration of each stage is also different; before the instability of the two kinds of rocks, there is a quiet period of acoustic emission, and the higher the rock strength, the longer the duration of this quiet period, which means that the calm period can be used as a precursor feature of rock mass instability for disaster prediction; during the cyclic loading process of rock, the damage development law is divided into three stages: initial stage, stable stage, and instability stage. When the Kaiser effect did not appear for the two rock stresses before 20%, between 20% and 70% of the peak strength, the Kaiser effect is obvious. When the stress exceeds 80% of the peak value, the Kaiser effect fails, and the Felicity effect appears; the variation of the loading rate affects the variation of the acoustic emission event rate, and the increase of the loading rate leads to aggravated rock damage. The theoretical stress-strain curve can reasonably reflect the actual stress-strain characteristics of rock by combining the number of acoustic emission events with the rock damage model. The results are consistent with the acoustic emission test, which verifies the inevitable relationship between acoustic emission and damage to the rock.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"64 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73376188","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}
Studies have focused on describing the interactions between the fluid flow characteristics and structural deformation of fractures at the mesoscopic scale, which is a scale between the macroscale and the microscale. In this work, a three-dimensional numerical simulation based on the Navier-Stokes equation was carried out to investigate the effect of normal stress on the fracture morphology distribution, the fluid flow characteristics distribution, and the interdependence between the flow and stress in a single mesoscopic fracture. Two fracture surfaces of a mesoscopic rough-walled fracture model were created. Results suggest that the nonlinear relationship between the normal stress and deformation due to the area of the total closure increases unevenly. Distributions of the mechanical aperture are approximated well by a normal distribution. Change in the fluid flow is due to the increase in the fractional contact area. The low-velocity zones are surrounded by relatively smaller apertures, which gradually close and join the areas of total closure. Under the limitation of the total closure areas of the two fracture surfaces, the appearance of channel flow behavior. Compared with the flow in the X- and Y-directions, normal stress-induced flow anisotropy occurred. The mesoscopic quantitative relationship between the strains in terms of the mechanical/hydraulic aperture was determined and proven. A macroscopic relationship between the intrinsic permeability and the strain was deduced, which enhances the evaluation and design of various geological engineering applications in which fracture deformation is considered.
{"title":"Mesoscopic Deformation of a Hydraulic and Mechanical Aperture of a Single Fracture under Normal Stress","authors":"Haichun Ma, Jingping Wang, Jiazhong Qian, Q. Luo","doi":"10.2113/2023/1118957","DOIUrl":"https://doi.org/10.2113/2023/1118957","url":null,"abstract":"\u0000 Studies have focused on describing the interactions between the fluid flow characteristics and structural deformation of fractures at the mesoscopic scale, which is a scale between the macroscale and the microscale. In this work, a three-dimensional numerical simulation based on the Navier-Stokes equation was carried out to investigate the effect of normal stress on the fracture morphology distribution, the fluid flow characteristics distribution, and the interdependence between the flow and stress in a single mesoscopic fracture. Two fracture surfaces of a mesoscopic rough-walled fracture model were created. Results suggest that the nonlinear relationship between the normal stress and deformation due to the area of the total closure increases unevenly. Distributions of the mechanical aperture are approximated well by a normal distribution. Change in the fluid flow is due to the increase in the fractional contact area. The low-velocity zones are surrounded by relatively smaller apertures, which gradually close and join the areas of total closure. Under the limitation of the total closure areas of the two fracture surfaces, the appearance of channel flow behavior. Compared with the flow in the X- and Y-directions, normal stress-induced flow anisotropy occurred. The mesoscopic quantitative relationship between the strains in terms of the mechanical/hydraulic aperture was determined and proven. A macroscopic relationship between the intrinsic permeability and the strain was deduced, which enhances the evaluation and design of various geological engineering applications in which fracture deformation is considered.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"1 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-04-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88911814","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}
During the gas production process, the evaporation of formation water leads to an increase in the water content of the gas and increases the salinity of the remaining formation water. Salt deposition generally occurs near the wellbore and in the wellbore. When the wellbore is clogged with salt deposition, it will lead to a rapid decrease in gas well pressure and production. This work analyzes the effects of formation water evaporation, temperature, and pressure on salt deposition in gas wellbore. And the salt deposition mechanism in the wellbore was summarized. This work presented a technical review on the salt deposition prediction in the gas wellbore. Finally, this work summarizes three different techniques for salt deposition remediation in gas wells, including cold-water removal, hot-water washing, and chemical salt prevention. This work can provide a reference for salt deposition prevention and remediation in the underground gas storage.
{"title":"Review on Mechanism, Prediction, and Remediation of Salt Deposition in Gas Production Wells","authors":"Duocai Wang, Zhongxing Ren, Haichuan Li, Ping Jiang, Jian Wang, Yanwei Zhu, Ziheng Zhu","doi":"10.2113/2022/3718513","DOIUrl":"https://doi.org/10.2113/2022/3718513","url":null,"abstract":"\u0000 During the gas production process, the evaporation of formation water leads to an increase in the water content of the gas and increases the salinity of the remaining formation water. Salt deposition generally occurs near the wellbore and in the wellbore. When the wellbore is clogged with salt deposition, it will lead to a rapid decrease in gas well pressure and production. This work analyzes the effects of formation water evaporation, temperature, and pressure on salt deposition in gas wellbore. And the salt deposition mechanism in the wellbore was summarized. This work presented a technical review on the salt deposition prediction in the gas wellbore. Finally, this work summarizes three different techniques for salt deposition remediation in gas wells, including cold-water removal, hot-water washing, and chemical salt prevention. This work can provide a reference for salt deposition prevention and remediation in the underground gas storage.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"22 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80403931","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}
An a priori model for multipoint statistics (MPS) modeling approaches is a training image. Before using MPS modeling, it must be determined whether the training images satisfy the spatial statistical stationarity. Modeling can be performed using the regular MPS approach if a training image is stationary. Otherwise, an enhanced method of nonstationary modeling is required. For instance, partition-based nonstationary modeling is an option. This study proposes a nonstationary evaluation metric based on pattern tile distances. It is possible to more accurately quantify the characteristics of the various distributions of spatial structure features in the entire space and achieve the goal of quantitatively evaluating the nonstationary metrics of training images by quantifying the distances of lower-level subpatterns in the pattern. Furthermore, an automatic partitioning approach based on pattern tile discrepancy is proposed for nonstationary training images to avoid the subjective and inefficient issues of manual partitioning when the training images cannot meet the stationary requirement of MPS modeling.
{"title":"A Quantitative Evaluation Method for Nonstationarity of Training Image Based on Pattern Tiles Distance","authors":"Siyu Yu, Shaohua Li, Mengjiao Dou, Linye Su","doi":"10.2113/2022/1497122","DOIUrl":"https://doi.org/10.2113/2022/1497122","url":null,"abstract":"\u0000 An a priori model for multipoint statistics (MPS) modeling approaches is a training image. Before using MPS modeling, it must be determined whether the training images satisfy the spatial statistical stationarity. Modeling can be performed using the regular MPS approach if a training image is stationary. Otherwise, an enhanced method of nonstationary modeling is required. For instance, partition-based nonstationary modeling is an option. This study proposes a nonstationary evaluation metric based on pattern tile distances. It is possible to more accurately quantify the characteristics of the various distributions of spatial structure features in the entire space and achieve the goal of quantitatively evaluating the nonstationary metrics of training images by quantifying the distances of lower-level subpatterns in the pattern. Furthermore, an automatic partitioning approach based on pattern tile discrepancy is proposed for nonstationary training images to avoid the subjective and inefficient issues of manual partitioning when the training images cannot meet the stationary requirement of MPS modeling.","PeriodicalId":18147,"journal":{"name":"Lithosphere","volume":"19 1","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-04-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78272200","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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