Based on the analysis of Upper Paleozoic source rocks, source-reservoir-caprock assemblage, and gas accumulation characteristics in the Ordos Basin, the gas accumulation geological model of total petroleum system is d...Based on the analysis of Upper Paleozoic source rocks, source-reservoir-caprock assemblage, and gas accumulation characteristics in the Ordos Basin, the gas accumulation geological model of total petroleum system is determined. Then, taking the Carboniferous Benxi Formation and the Permian Taiyuan Formation and Shanxi Formation as examples, the main controlling factors of gas accumulation and enrichment are discussed, and the gas enrichment models of total petroleum system are established. The results show that the source rocks, faults and tight reservoirs and their mutual coupling relations control the distribution and enrichment of gas. Specifically, the distribution and hydrocarbon generation capacity of source rocks control the enrichment degree and distribution range of retained shale gas and tight gas in the source. The coupling between the hydrocarbon generation capacity of source rocks and the physical properties of tight reservoirs controls the distribution and sweet spot development of near-source tight gas in the basin center. The far-source tight gas in the basin margin is mainly controlled by the distribution of faults, and the distribution of inner-source, near-source and far-source gas is adjusted and reformed by faults. Generally, the Upper Paleozoic gas in the Ordos Basin is recognized in four enrichment models: inner-source coalbed gas and shale gas, inner-source tight sandstone gas, near-source tight gas, and far-source fault-transported gas. In the Ordos Basin, inner-source tight gas and near-source tight gas are the current focuses of exploration, and inner-source coalbed gas and shale gas and far-source gas will be important potential targets in the future.展开更多
The remediation of crude oil-impacted soil has always been a challenge in different soil environments and climatic conditions. Bioremediation technology has offered a breakthrough in restoring crude oil-impacted soil/...The remediation of crude oil-impacted soil has always been a challenge in different soil environments and climatic conditions. Bioremediation technology has offered a breakthrough in restoring crude oil-impacted soil/sediment in muddy, dry soil and wetlands. Though, there have been varied environmental conditions that have hampered the success of the bioremediation process. This study has evaluated the effectiveness of a biostimulated bioremediation of crude oil-impacted soil using some design criteria—nutrient amendment (NPK fertilizer) and moisture content. Soil sample sets—A, B, C, D, E, F, and G were impacted with crude oil at a ratio of 10 g/kg and amended with varying amounts of nutrient 30, 60, and 80 g of N.P.K fertilizer. The medium for the inoculation of the nutrient was water and the volume of water applied varied from 30% to 80% saturation. The soil sample sets were harvested at an interval of 3 months for 180 days to determine the concentration of total petroleum hydrocarbon left in the soil. The analysis of the total petroleum hydrocarbon was achieved using a GC-FID with a capillary column and autosampler. Soil samples were extracted with mixed solvent dichloromethane and acetone at a 1:1 ratio. The total petroleum hydrocarbon results show that biostimulated bioremediation achieved better results in soil sample sets with low moisture content (30% water saturation) and moderate nutrient amendment. The biodegradation of the sample sets with high water saturation and a high nutrient amendment was slow with a higher amount of total hydrocarbon content at the end of the 180 days. The variability in the hydrocarbon degradation pattern of contaminated soil shows that biostimulated bioremediation achieved better results in soils with low moisture content than in soil environments with high water content (saturation). More so, nutrient overdosing of the substrate hampered the effectiveness of the remediation process.展开更多
The coastal area is one of the areas that is quite vulnerable to the threat of pollution caused by human activities,including pollution caused by oil spills(hydrocarbons)in the sea.The incident can be caused by severa...The coastal area is one of the areas that is quite vulnerable to the threat of pollution caused by human activities,including pollution caused by oil spills(hydrocarbons)in the sea.The incident can be caused by several factors including the explosion,leakage of petroleum pipelines on the seabed,leakage of tanks or petroleum tankers at sea and disposal of waste petroleum products into the environment.Oil spills continuously can cause environmental contamination and pollution both aquatic and terrestrial.If the petroleum hydrocarbons enter sea waters,some of them will be absorbed by aquatic organisms because the nature of the petroleum hydrocarbons is difficult to decompose in waters.The intentional and unintentional entry of hazardous and toxic substances into marine ecosystems such as petroleum hydrocarbons and chemical solvents resulting from industrial wastes has become a serious problem for human health and the environment.The purpose of this study was to determine the concentration of Total Petroleum Hydrocarbon(TPH)contained in fish in coastal waters of Karawang Regency,West Java Province.This research was conducted in September-November 2019 by taking several fish samples at Ciparage Jaya Fish Auction Place,Betok Mati and Sungai Buntu Rive with a total sample of 24 fish,and taking seawater samples in the three study sites.TPH analysis was carried out at the Integrated Chemistry Laboratory,Bogor Agricultural University.TPH values in fish at Ciparage-1,Ciparage-2,Betok Mati and Sungai Buntu stations,in general,have different mean values but are almost uniform,each at 6.82;6.82;7.45 and 5.12 mg/kg.Based on the average TPH concentration in fish,it can be said that the average TPH in fish at Betok Mati station is relatively higher compared to other stations.TPH values in all fish samples exceed the safe threshold,which is a maximum of 0.002 mg/kg.Based on the results of the Bioaccumulation factor(BAF)analysis showed that the average TPH in fish was 6.55 mg/kg and the average TPH in the waters was 11.23 mg/l,so the BAF value was 58.35 which means that the absorption rate of TPH by fish organisms against the concentration of TPH in the waters of 58.35%.The analysis shows that the value of Ecological Hazard Assessment(EHA)is 3743.33 which means that the level of influence of the hazard on ecosystems and organisms is 3743.33.This value exceeds the recommended threshold according to the European Union,which is a maximum of 0.002 mg/l.展开更多
This study investigates the volatility in daily stock returns for Total Nigeria Plc using nine variants of GARCH models:sGARCH,girGARCH,eGARCH,iGARCH,aGARCH,TGARCH,NGARCH,NAGARCH,and AVGARCH along with value at risk e...This study investigates the volatility in daily stock returns for Total Nigeria Plc using nine variants of GARCH models:sGARCH,girGARCH,eGARCH,iGARCH,aGARCH,TGARCH,NGARCH,NAGARCH,and AVGARCH along with value at risk estimation and backtesting.We use daily data for Total Nigeria Plc returns for the period January 2,2001 to May 8,2017,and conclude that eGARCH and sGARCH perform better for normal innovations while NGARCH performs better for student t innovations.This investigation of the volatility,VaR,and backtesting of the daily stock price of Total Nigeria Plc is important as most previous studies covering the Nigerian stock market have not paid much attention to the application of backtesting as a primary approach.We found from the results of the estimations that the persistence of the GARCH models are stable except for few cases for which iGARCH and eGARCH were unstable.Additionally,for student t innovation,the sGARCH and girGARCH models failed to converge;the mean reverting number of days for returns differed from model to model.From the analysis of VaR and its backtesting,this study recommends shareholders and investors continue their business with Total Nigeria Plc because possible losses may be overcome in the future by improvements in stock prices.Furthermore,risk was reflected by significant up and down movement in the stock price at a 99%confidence level,suggesting that high risk brings a high return.展开更多
A computational fluid dynamics(CFD)numerical simulation and field experiment were used to investigate optimal operating parameters of high-pressure jet grouting equipment and clarify the boundary law of the injection ...A computational fluid dynamics(CFD)numerical simulation and field experiment were used to investigate optimal operating parameters of high-pressure jet grouting equipment and clarify the boundary law of the injection area in the remediation process.The response surface optimization design results show that the optimal injection pressure is 30 MPa,rotation speed is 23 r/min,commission speed is 30 cm/min,and the optimal injection diameter is 147.3 cm.Based on the CFD numerical simulation,the ratio of the injection core,turbulent zone,and seepage zone is approximately 1∶4∶2.The distribution law of jet core,turbulence zone and seepage zone at different cross-sections under 30 MPa operating conditions is as follows:The jet core radius is approximately 100 mm,the turbulence zone is mainly distributed at 100 to 500 mm,the seepage zone is mainly distributed at 500 to 700 mm,the seepage zone could be completed within 2 h,and the proportion of the three boundary zones in the injection zone is similar to that of the numerical simulation.This study provides theoretical parameters and practical reference for the remediation of deep pollution via in-situ chemical oxidation in the Loess Plateau soil environment.展开更多
基金Supported by the National Natural Science Foundation of China (41872128)the CNPC Major Science and Technology Project (2021DJ0101)。
文摘Based on the analysis of Upper Paleozoic source rocks, source-reservoir-caprock assemblage, and gas accumulation characteristics in the Ordos Basin, the gas accumulation geological model of total petroleum system is determined. Then, taking the Carboniferous Benxi Formation and the Permian Taiyuan Formation and Shanxi Formation as examples, the main controlling factors of gas accumulation and enrichment are discussed, and the gas enrichment models of total petroleum system are established. The results show that the source rocks, faults and tight reservoirs and their mutual coupling relations control the distribution and enrichment of gas. Specifically, the distribution and hydrocarbon generation capacity of source rocks control the enrichment degree and distribution range of retained shale gas and tight gas in the source. The coupling between the hydrocarbon generation capacity of source rocks and the physical properties of tight reservoirs controls the distribution and sweet spot development of near-source tight gas in the basin center. The far-source tight gas in the basin margin is mainly controlled by the distribution of faults, and the distribution of inner-source, near-source and far-source gas is adjusted and reformed by faults. Generally, the Upper Paleozoic gas in the Ordos Basin is recognized in four enrichment models: inner-source coalbed gas and shale gas, inner-source tight sandstone gas, near-source tight gas, and far-source fault-transported gas. In the Ordos Basin, inner-source tight gas and near-source tight gas are the current focuses of exploration, and inner-source coalbed gas and shale gas and far-source gas will be important potential targets in the future.
文摘The remediation of crude oil-impacted soil has always been a challenge in different soil environments and climatic conditions. Bioremediation technology has offered a breakthrough in restoring crude oil-impacted soil/sediment in muddy, dry soil and wetlands. Though, there have been varied environmental conditions that have hampered the success of the bioremediation process. This study has evaluated the effectiveness of a biostimulated bioremediation of crude oil-impacted soil using some design criteria—nutrient amendment (NPK fertilizer) and moisture content. Soil sample sets—A, B, C, D, E, F, and G were impacted with crude oil at a ratio of 10 g/kg and amended with varying amounts of nutrient 30, 60, and 80 g of N.P.K fertilizer. The medium for the inoculation of the nutrient was water and the volume of water applied varied from 30% to 80% saturation. The soil sample sets were harvested at an interval of 3 months for 180 days to determine the concentration of total petroleum hydrocarbon left in the soil. The analysis of the total petroleum hydrocarbon was achieved using a GC-FID with a capillary column and autosampler. Soil samples were extracted with mixed solvent dichloromethane and acetone at a 1:1 ratio. The total petroleum hydrocarbon results show that biostimulated bioremediation achieved better results in soil sample sets with low moisture content (30% water saturation) and moderate nutrient amendment. The biodegradation of the sample sets with high water saturation and a high nutrient amendment was slow with a higher amount of total hydrocarbon content at the end of the 180 days. The variability in the hydrocarbon degradation pattern of contaminated soil shows that biostimulated bioremediation achieved better results in soils with low moisture content than in soil environments with high water content (saturation). More so, nutrient overdosing of the substrate hampered the effectiveness of the remediation process.
文摘The coastal area is one of the areas that is quite vulnerable to the threat of pollution caused by human activities,including pollution caused by oil spills(hydrocarbons)in the sea.The incident can be caused by several factors including the explosion,leakage of petroleum pipelines on the seabed,leakage of tanks or petroleum tankers at sea and disposal of waste petroleum products into the environment.Oil spills continuously can cause environmental contamination and pollution both aquatic and terrestrial.If the petroleum hydrocarbons enter sea waters,some of them will be absorbed by aquatic organisms because the nature of the petroleum hydrocarbons is difficult to decompose in waters.The intentional and unintentional entry of hazardous and toxic substances into marine ecosystems such as petroleum hydrocarbons and chemical solvents resulting from industrial wastes has become a serious problem for human health and the environment.The purpose of this study was to determine the concentration of Total Petroleum Hydrocarbon(TPH)contained in fish in coastal waters of Karawang Regency,West Java Province.This research was conducted in September-November 2019 by taking several fish samples at Ciparage Jaya Fish Auction Place,Betok Mati and Sungai Buntu Rive with a total sample of 24 fish,and taking seawater samples in the three study sites.TPH analysis was carried out at the Integrated Chemistry Laboratory,Bogor Agricultural University.TPH values in fish at Ciparage-1,Ciparage-2,Betok Mati and Sungai Buntu stations,in general,have different mean values but are almost uniform,each at 6.82;6.82;7.45 and 5.12 mg/kg.Based on the average TPH concentration in fish,it can be said that the average TPH in fish at Betok Mati station is relatively higher compared to other stations.TPH values in all fish samples exceed the safe threshold,which is a maximum of 0.002 mg/kg.Based on the results of the Bioaccumulation factor(BAF)analysis showed that the average TPH in fish was 6.55 mg/kg and the average TPH in the waters was 11.23 mg/l,so the BAF value was 58.35 which means that the absorption rate of TPH by fish organisms against the concentration of TPH in the waters of 58.35%.The analysis shows that the value of Ecological Hazard Assessment(EHA)is 3743.33 which means that the level of influence of the hazard on ecosystems and organisms is 3743.33.This value exceeds the recommended threshold according to the European Union,which is a maximum of 0.002 mg/l.
文摘This study investigates the volatility in daily stock returns for Total Nigeria Plc using nine variants of GARCH models:sGARCH,girGARCH,eGARCH,iGARCH,aGARCH,TGARCH,NGARCH,NAGARCH,and AVGARCH along with value at risk estimation and backtesting.We use daily data for Total Nigeria Plc returns for the period January 2,2001 to May 8,2017,and conclude that eGARCH and sGARCH perform better for normal innovations while NGARCH performs better for student t innovations.This investigation of the volatility,VaR,and backtesting of the daily stock price of Total Nigeria Plc is important as most previous studies covering the Nigerian stock market have not paid much attention to the application of backtesting as a primary approach.We found from the results of the estimations that the persistence of the GARCH models are stable except for few cases for which iGARCH and eGARCH were unstable.Additionally,for student t innovation,the sGARCH and girGARCH models failed to converge;the mean reverting number of days for returns differed from model to model.From the analysis of VaR and its backtesting,this study recommends shareholders and investors continue their business with Total Nigeria Plc because possible losses may be overcome in the future by improvements in stock prices.Furthermore,risk was reflected by significant up and down movement in the stock price at a 99%confidence level,suggesting that high risk brings a high return.
基金The National Natural Science Foundation of China(No.41967043,52160003)the Natural Science Foundation of Gansu Province(No.20JR5RA461)+1 种基金the Key Project of China Railway Southwest Research Institute Co.,Ltd.(No.2018-KJ003-Z003-XB)the Industrial Support Program of the Higher Education of Gansu Province(No.2020C-40).
文摘A computational fluid dynamics(CFD)numerical simulation and field experiment were used to investigate optimal operating parameters of high-pressure jet grouting equipment and clarify the boundary law of the injection area in the remediation process.The response surface optimization design results show that the optimal injection pressure is 30 MPa,rotation speed is 23 r/min,commission speed is 30 cm/min,and the optimal injection diameter is 147.3 cm.Based on the CFD numerical simulation,the ratio of the injection core,turbulent zone,and seepage zone is approximately 1∶4∶2.The distribution law of jet core,turbulence zone and seepage zone at different cross-sections under 30 MPa operating conditions is as follows:The jet core radius is approximately 100 mm,the turbulence zone is mainly distributed at 100 to 500 mm,the seepage zone is mainly distributed at 500 to 700 mm,the seepage zone could be completed within 2 h,and the proportion of the three boundary zones in the injection zone is similar to that of the numerical simulation.This study provides theoretical parameters and practical reference for the remediation of deep pollution via in-situ chemical oxidation in the Loess Plateau soil environment.