Erosion of carbonate strata not only can reflect the karst landform,but also can reveal the characteristics of carbonate karst reservoirs indirectly.In Sichuan Basin,the quantity and root causes of lacuna in the top s...Erosion of carbonate strata not only can reflect the karst landform,but also can reveal the characteristics of carbonate karst reservoirs indirectly.In Sichuan Basin,the quantity and root causes of lacuna in the top strata of the Maokou Fm are unclear.In this paper,the features of such stratigraphic lacuna were analyzed qualitatively.Then,in accordance with the spectral transformation of GR logs and the characteristics of cycle in the Maokou Fm penetrated by four typical wells,the Milankovich cycles of the logs were identified.Then they were used for quantitative calculation of erosion quantity and for highlighting the root causes for the stratigraphic lacuna.According to the research results,the Mao-4 Member is residual in the Yibin-Ya'an-Jiangyou area and the Shizhu area,but missing in the other parts of Sichuan Basin with a stratigraphic lacuna intensity gradually increasing from the southern part to the central part and to the northern parts of the basin.Besides,the stratigraphic lacuna of the Maokou Fm varies from 0 to 200 m-for example,0-60 m in the southwestern and northeastern parts of the basin,and 140-200 m in the southern,central and northern parts of the basin.Moreover,formation denudation occurred at the end of the Maokou Period was induced predominantly by erosion generated as the sea level fell during the glacial age,especially in the northern part of the basin.Also,the Mid-Permian karst landform inherited the sedimentary features of being high in the southwest and low in the northeast.In the areas from the southwestern to central and to the northern Sichuan Basin,the karst landform transits from erosion highlands to karst upper and lower slopes,coinciding well with the sedimentary features of the Wujiaping Period.In conclusion,the Milankovich cycles can be used to calculate the stratigraphic erosion in carbonate formations efficiently and accurately.The technique can be extended to the restoration of stratigraphic erosion in other marine basins.展开更多
Quantitative thickness estimation below tuning thickness is a great challenge in seismic exploration. Most studies focus on the thin-beds whose top and bottom reflection coefficients are of equal magnitude and opposit...Quantitative thickness estimation below tuning thickness is a great challenge in seismic exploration. Most studies focus on the thin-beds whose top and bottom reflection coefficients are of equal magnitude and opposite polarity. There is no systematic research on the other thin-bed types. In this article, all of the thin-beds are classified into four types： thin-beds with equal magnitude and opposite polarity, thin-beds with unequal magnitude and opposite polarity, thin-beds with equal magnitude and identical polarity, and thin-beds with unequal magnitude and identical polarity. By analytical study, an equation describing the general relationship between seismic peak frequency and thin-bed thickness was derived which shows there is a Complex implicit non-linear relationship between them and which is difficult to use in practice. In order to solve this problem, we simplify the relationship by Taylor expansion and discuss the precision of the approximation formulae with different orders for the four types of thin-beds. Compared with the traditional amplitude method for thin-bed thickness calculation, the method we present has a higher precision and isn＇t influenced by the absolute value of top or bottom reflection coefficient, so it is convenient for use in practice.展开更多
A comfortable environment in railway passenger coaches can be regarded as a resource for social consumption during the transport process. Railway passenger comfort benefits （RPCBs） can be regarded as a special gener...A comfortable environment in railway passenger coaches can be regarded as a resource for social consumption during the transport process. Railway passenger comfort benefits （RPCBs） can be regarded as a special generalized cost. In this paper, we select a series of objective and subjective indexes to formulate a quantitative method of calculating the RPCB with considering ticket fares. This method includes three steps： make the initial data dimensionless, calculate the weight of each index, and finally calculate the RPCBs. The proposed method was validated with the data collected from two types of trains： G13 from Beijing South to Shanghai Hongqiao and T109 from Beijing to Shanghai. Also, questionnaire survey was conducted in both trains. After data processing, the results show that there is a linear relationship between the RPCB and ticket fare with a correlation coefficient of 0.9616.展开更多
The aim of this study was to quantitatively evaluate the influences of landscape composition and spatial structure on the transmission process of non-point source pollutants in different regions.The location-weighted ...The aim of this study was to quantitatively evaluate the influences of landscape composition and spatial structure on the transmission process of non-point source pollutants in different regions.The location-weighted landscape contrast index,using the hydrological response unit(HRULCI)as the minimum research unit,was proposed in this paper.Through the description of the endemic landscape types and various geographical factors in the basin,the index calculation can reflect the impact of the“source-sink”landscape structure on the non-point source pollution in different regions and quantitatively evaluate the contribution of different landscape types and geographical factors to non-point source pollution.This study constructed a method of geo-cognitive computing for identifying“source-sink”landscape patterns of river basin non-point source pollution at two levels.1)The basin level:the spatial distribution and landscape combination of the entire basin are identified,and the crucial“source”and“sink”landscape types are obtained to measure the differences in the non-point source pollutant transmission processes between the“source”and“sink”landscapes in the different watersheds.2)The landscape level:HRULCI is calculated based on multiple geographical correction weighting factors.By using the idea of intersecting geographic information system(GIS)and landscape ecology,the landscape spatial pattern and ecological processes are linked.Compared with the traditional method for studying landscape patterns,the calculation of HRULCI makes the proposed method more ecologically significant.Lastly,a case study was evaluated to verify the significance of the proposed research method by taking the Yanshi River basin,a sub-basin belonging to the Jiulong River basin located in Fujian Province,China,as the experimental study zone.The results showed that this method can reflect the spatial distribution characteristics of the“source-sink”types and their relationship with non-point source pollution.By comparing the resulting calculation based on HRULCI,the risk of nutrient loss and the influence of landscape patterns and ecological processes on non-point pollution in different catchments can be obtained.展开更多
基金Project supported by the National Major Science and Technology Project“Distribution Law and Evaluation of Deep Oil and Gas Resources in China's Petroliferous Basins”(No.2016ZX05008-006).
文摘Erosion of carbonate strata not only can reflect the karst landform,but also can reveal the characteristics of carbonate karst reservoirs indirectly.In Sichuan Basin,the quantity and root causes of lacuna in the top strata of the Maokou Fm are unclear.In this paper,the features of such stratigraphic lacuna were analyzed qualitatively.Then,in accordance with the spectral transformation of GR logs and the characteristics of cycle in the Maokou Fm penetrated by four typical wells,the Milankovich cycles of the logs were identified.Then they were used for quantitative calculation of erosion quantity and for highlighting the root causes for the stratigraphic lacuna.According to the research results,the Mao-4 Member is residual in the Yibin-Ya'an-Jiangyou area and the Shizhu area,but missing in the other parts of Sichuan Basin with a stratigraphic lacuna intensity gradually increasing from the southern part to the central part and to the northern parts of the basin.Besides,the stratigraphic lacuna of the Maokou Fm varies from 0 to 200 m-for example,0-60 m in the southwestern and northeastern parts of the basin,and 140-200 m in the southern,central and northern parts of the basin.Moreover,formation denudation occurred at the end of the Maokou Period was induced predominantly by erosion generated as the sea level fell during the glacial age,especially in the northern part of the basin.Also,the Mid-Permian karst landform inherited the sedimentary features of being high in the southwest and low in the northeast.In the areas from the southwestern to central and to the northern Sichuan Basin,the karst landform transits from erosion highlands to karst upper and lower slopes,coinciding well with the sedimentary features of the Wujiaping Period.In conclusion,the Milankovich cycles can be used to calculate the stratigraphic erosion in carbonate formations efficiently and accurately.The technique can be extended to the restoration of stratigraphic erosion in other marine basins.
基金supported by National Key S&T Special Projects of Marine Carbonate 2008ZX05000-004CNPC Projects 2008E-0610-10
文摘Quantitative thickness estimation below tuning thickness is a great challenge in seismic exploration. Most studies focus on the thin-beds whose top and bottom reflection coefficients are of equal magnitude and opposite polarity. There is no systematic research on the other thin-bed types. In this article, all of the thin-beds are classified into four types： thin-beds with equal magnitude and opposite polarity, thin-beds with unequal magnitude and opposite polarity, thin-beds with equal magnitude and identical polarity, and thin-beds with unequal magnitude and identical polarity. By analytical study, an equation describing the general relationship between seismic peak frequency and thin-bed thickness was derived which shows there is a Complex implicit non-linear relationship between them and which is difficult to use in practice. In order to solve this problem, we simplify the relationship by Taylor expansion and discuss the precision of the approximation formulae with different orders for the four types of thin-beds. Compared with the traditional amplitude method for thin-bed thickness calculation, the method we present has a higher precision and isn＇t influenced by the absolute value of top or bottom reflection coefficient, so it is convenient for use in practice.
基金jointly supported by the Traffic and Transportation Engineering Experiment and Comprehensive Innovation Center, School of Transportation and Logistics, Southwest Jiaotong University, Chengdu Sichuansubsidized by National Natural Science Foundation of China (71173177)+1 种基金China State Railway Administration of Science and Technology Legal Division (KF2013-020)2015 Graduate Innovative Experimental and Practice Program (YC201507103), Southwest Jiaotong University
文摘A comfortable environment in railway passenger coaches can be regarded as a resource for social consumption during the transport process. Railway passenger comfort benefits （RPCBs） can be regarded as a special generalized cost. In this paper, we select a series of objective and subjective indexes to formulate a quantitative method of calculating the RPCB with considering ticket fares. This method includes three steps： make the initial data dimensionless, calculate the weight of each index, and finally calculate the RPCBs. The proposed method was validated with the data collected from two types of trains： G13 from Beijing South to Shanghai Hongqiao and T109 from Beijing to Shanghai. Also, questionnaire survey was conducted in both trains. After data processing, the results show that there is a linear relationship between the RPCB and ticket fare with a correlation coefficient of 0.9616.
基金funded by the National Key R&D Programs of China(Grant No.2017YFB0504201,2015BAJ02B02)the Natural Science Foundation of China(Grant No.61473286,61375002)the Natural Science Foundation of Hainan Province(Grant No.20164178).
文摘The aim of this study was to quantitatively evaluate the influences of landscape composition and spatial structure on the transmission process of non-point source pollutants in different regions.The location-weighted landscape contrast index,using the hydrological response unit(HRULCI)as the minimum research unit,was proposed in this paper.Through the description of the endemic landscape types and various geographical factors in the basin,the index calculation can reflect the impact of the“source-sink”landscape structure on the non-point source pollution in different regions and quantitatively evaluate the contribution of different landscape types and geographical factors to non-point source pollution.This study constructed a method of geo-cognitive computing for identifying“source-sink”landscape patterns of river basin non-point source pollution at two levels.1)The basin level:the spatial distribution and landscape combination of the entire basin are identified,and the crucial“source”and“sink”landscape types are obtained to measure the differences in the non-point source pollutant transmission processes between the“source”and“sink”landscapes in the different watersheds.2)The landscape level:HRULCI is calculated based on multiple geographical correction weighting factors.By using the idea of intersecting geographic information system(GIS)and landscape ecology,the landscape spatial pattern and ecological processes are linked.Compared with the traditional method for studying landscape patterns,the calculation of HRULCI makes the proposed method more ecologically significant.Lastly,a case study was evaluated to verify the significance of the proposed research method by taking the Yanshi River basin,a sub-basin belonging to the Jiulong River basin located in Fujian Province,China,as the experimental study zone.The results showed that this method can reflect the spatial distribution characteristics of the“source-sink”types and their relationship with non-point source pollution.By comparing the resulting calculation based on HRULCI,the risk of nutrient loss and the influence of landscape patterns and ecological processes on non-point pollution in different catchments can be obtained.
