For the path dependency and nonlinearity introduced by incremental construction, numerical method has been widely used in deformation analysis of geo engineering.In the numerical simulation scheme commonly used in the...For the path dependency and nonlinearity introduced by incremental construction, numerical method has been widely used in deformation analysis of geo engineering.In the numerical simulation scheme commonly used in the past, the excavating loads are extracted from nodal stresses, which are deduced linearly from the stresses at Gauss point in finite element method.The unneglectable calculation error is contained in this process when elastic plastic constitutive model is employed.The error mentioned above is analyzed in detail.Based on the analysis of excavation process and the principle of finite element theory, a new simulation scheme for excavation is proposed.At the end of this paper, an application in rock engineering is given out.展开更多
Optical fiber sensing technology has developed rapidly since the 1980s with the development of the optical fiber and fiber optical communication technology.It is a new type of sensing technology that uses light as a c...Optical fiber sensing technology has developed rapidly since the 1980s with the development of the optical fiber and fiber optical communication technology.It is a new type of sensing technology that uses light as a carrier and optical fiber as a medium to sense and transmit external signals(measurands).Distributed fiber optical sensors(DFOS)can continuously measure the external physical parameters distributed along the geometric path of the optical fiber.Meanwhile,the spatial distribution and change information of the measured physical parameters over time can be obtained.This technology has unmatched advantages over traditional point-wise and electrical measurement monitoring technologies.This paper summarizes the state-of-the-art research of the application of the distributed optical fiber sensing tech no logy in geo-engineering in the past 10 years,mainly including the advantages of DFOS,the challenges in geo-engineering monitoring,related fundamental theoretical issues,sensing performance of the optical sensing cables,distributed optical fiber monitoring system for geo-engineering,and applications of optical fiber sensing technology in geo-engineering.展开更多
Shale gas resource in China is greatly different from that in the North America in term of natural endowment,so North America's experience and practice of shale gas revolution shall not be copied blindly in China....Shale gas resource in China is greatly different from that in the North America in term of natural endowment,so North America's experience and practice of shale gas revolution shall not be copied blindly in China.In order to realize scale effective development of shale gas resource in China,we analyzed and summarized the status quo of domestic shale gas stimulation technologies referring to the advanced concepts of shale gas development in the North America,considering the actual situations of shale gas resource in China.Then,some suggestions were proposed on the development direction of key shale gas fracturing technologies and the enhancement of engineering management.First,a data volume that integrates geological,engineering and production information is the base for designing and optimizing all segments of shale gas exploration,development and production.Therefore,it is necessary to break the“data isolated island”,strengthen data mining and improve the data application efficiency,so as to promote the integration of geo-engineering data fusion.Second,the geomechanics test&evaluation method and technology suitable for shale reservoirs shall be developed and improved by taking into consideration the anisotropic mechanical behaviors and ground stress characteristics of shale reservoirs,so as to increase the design level of geo-engineering integration program.Third,it is necessary to develop the dissolvable bridge plug,improve operation the efficiency of staged fracturing and reduce the operation risk,so as to achieve cost reduction and benefit increase of shale gas development.Fourth,there is still great room for the improvement of the engineering management system,which is worth exploring and studying further.Therefore,oil&gas industry and companies shall seize this critical strategic opportunity to actively optimize the current engineering management pattern and seek the optimal approach to quality improving and benefit increasing.In conclusion,the exploration and development of shale gas in China is currently in the early stage and there is an obvious gap compared with foreign countries in terms of technology&equipment,production management,exploration and development achievement and policy®ulation.Therefore,it is in an urgent need to innovatively explore a way feasible for the actual shale gas development in China based on the resource conditions of its own after referring,digesting and absorbing the hydraulic fracturing experience and management concept of shale gas revolution in the United States.展开更多
Throughout the industrial period,anthropogenic aerosols have likely offset approximately one-third of the warming caused by greenhouse gases.Marine cloud brightening aims to capitalize on one aspect of this phenomenon...Throughout the industrial period,anthropogenic aerosols have likely offset approximately one-third of the warming caused by greenhouse gases.Marine cloud brightening aims to capitalize on one aspect of this phenomenon to potentially mitigate global warming by enhancing cloud reflectivity through adjustments in cloud droplet concentration.This study employs a simplified yet comprehensive modeling framework,integrating an open-source parcel model for aerosol activation,a radiation transport model based on commercial computational fluid dynamics code,and assimilated meteorological data.The reduced complexity model addresses the challenges of rapid radiation transfer calculations while managing uncertainties in aerosol–cloud-radiation(ACR)parameterizations.Despite using an uncoupled ACR mechanism and omitting feedback between clouds and aerosols,our results closely align with observations,validating the robustness of our assumptions and methodology.This demonstrates that even simplified models,supported by parcel modeling and observational constraints,can achieve accurate radiation transfer calculations comparable to advanced climate models.We analyze how variations in droplets size and concentration affect cloud albedo for geoengineering applications.Optimal droplet sizes,typically within the 20–35-µm range,significantly increase cloud albedo by approximately 28%–57%across our test cases.We find that droplets transmit about 29%more solar radiation than droplets.Effective albedo changes require injection concentrations exceeding background levels by around 30%,diminishing as concentrations approach ambient levels.Considerations must also be given to the spray pattern of droplet injections,as effective deployment can influence cloud thickness and subsequently impact cloud albedo.This research provides insights into the feasibility and effectiveness of using a reduced complexity model for marine cloud brightening with frontal cyclone and stratus cumulus clouds,and emphasizes the need to also consider background droplets size and concentration than just meteorological conditions.展开更多
文摘For the path dependency and nonlinearity introduced by incremental construction, numerical method has been widely used in deformation analysis of geo engineering.In the numerical simulation scheme commonly used in the past, the excavating loads are extracted from nodal stresses, which are deduced linearly from the stresses at Gauss point in finite element method.The unneglectable calculation error is contained in this process when elastic plastic constitutive model is employed.The error mentioned above is analyzed in detail.Based on the analysis of excavation process and the principle of finite element theory, a new simulation scheme for excavation is proposed.At the end of this paper, an application in rock engineering is given out.
基金supported by the National Natural Science Foundation of China(Grant Nos.42030701,41427801,and 42077233).
文摘Optical fiber sensing technology has developed rapidly since the 1980s with the development of the optical fiber and fiber optical communication technology.It is a new type of sensing technology that uses light as a carrier and optical fiber as a medium to sense and transmit external signals(measurands).Distributed fiber optical sensors(DFOS)can continuously measure the external physical parameters distributed along the geometric path of the optical fiber.Meanwhile,the spatial distribution and change information of the measured physical parameters over time can be obtained.This technology has unmatched advantages over traditional point-wise and electrical measurement monitoring technologies.This paper summarizes the state-of-the-art research of the application of the distributed optical fiber sensing tech no logy in geo-engineering in the past 10 years,mainly including the advantages of DFOS,the challenges in geo-engineering monitoring,related fundamental theoretical issues,sensing performance of the optical sensing cables,distributed optical fiber monitoring system for geo-engineering,and applications of optical fiber sensing technology in geo-engineering.
基金supported by the National Key Research and Development Project“Water-Energy Nexus and Key Technologies on Efficient and Green Utilization of Water and Energy Resources”(No.2018YFE0196000).
文摘Shale gas resource in China is greatly different from that in the North America in term of natural endowment,so North America's experience and practice of shale gas revolution shall not be copied blindly in China.In order to realize scale effective development of shale gas resource in China,we analyzed and summarized the status quo of domestic shale gas stimulation technologies referring to the advanced concepts of shale gas development in the North America,considering the actual situations of shale gas resource in China.Then,some suggestions were proposed on the development direction of key shale gas fracturing technologies and the enhancement of engineering management.First,a data volume that integrates geological,engineering and production information is the base for designing and optimizing all segments of shale gas exploration,development and production.Therefore,it is necessary to break the“data isolated island”,strengthen data mining and improve the data application efficiency,so as to promote the integration of geo-engineering data fusion.Second,the geomechanics test&evaluation method and technology suitable for shale reservoirs shall be developed and improved by taking into consideration the anisotropic mechanical behaviors and ground stress characteristics of shale reservoirs,so as to increase the design level of geo-engineering integration program.Third,it is necessary to develop the dissolvable bridge plug,improve operation the efficiency of staged fracturing and reduce the operation risk,so as to achieve cost reduction and benefit increase of shale gas development.Fourth,there is still great room for the improvement of the engineering management system,which is worth exploring and studying further.Therefore,oil&gas industry and companies shall seize this critical strategic opportunity to actively optimize the current engineering management pattern and seek the optimal approach to quality improving and benefit increasing.In conclusion,the exploration and development of shale gas in China is currently in the early stage and there is an obvious gap compared with foreign countries in terms of technology&equipment,production management,exploration and development achievement and policy®ulation.Therefore,it is in an urgent need to innovatively explore a way feasible for the actual shale gas development in China based on the resource conditions of its own after referring,digesting and absorbing the hydraulic fracturing experience and management concept of shale gas revolution in the United States.
文摘Throughout the industrial period,anthropogenic aerosols have likely offset approximately one-third of the warming caused by greenhouse gases.Marine cloud brightening aims to capitalize on one aspect of this phenomenon to potentially mitigate global warming by enhancing cloud reflectivity through adjustments in cloud droplet concentration.This study employs a simplified yet comprehensive modeling framework,integrating an open-source parcel model for aerosol activation,a radiation transport model based on commercial computational fluid dynamics code,and assimilated meteorological data.The reduced complexity model addresses the challenges of rapid radiation transfer calculations while managing uncertainties in aerosol–cloud-radiation(ACR)parameterizations.Despite using an uncoupled ACR mechanism and omitting feedback between clouds and aerosols,our results closely align with observations,validating the robustness of our assumptions and methodology.This demonstrates that even simplified models,supported by parcel modeling and observational constraints,can achieve accurate radiation transfer calculations comparable to advanced climate models.We analyze how variations in droplets size and concentration affect cloud albedo for geoengineering applications.Optimal droplet sizes,typically within the 20–35-µm range,significantly increase cloud albedo by approximately 28%–57%across our test cases.We find that droplets transmit about 29%more solar radiation than droplets.Effective albedo changes require injection concentrations exceeding background levels by around 30%,diminishing as concentrations approach ambient levels.Considerations must also be given to the spray pattern of droplet injections,as effective deployment can influence cloud thickness and subsequently impact cloud albedo.This research provides insights into the feasibility and effectiveness of using a reduced complexity model for marine cloud brightening with frontal cyclone and stratus cumulus clouds,and emphasizes the need to also consider background droplets size and concentration than just meteorological conditions.
