Huaihe River Basin(HRB) is located in China’s north-south climatic transition zone,which is very sensitive to global climate change.Based on the daily maximum temperature,minimum temperature,and precipitation data of...Huaihe River Basin(HRB) is located in China’s north-south climatic transition zone,which is very sensitive to global climate change.Based on the daily maximum temperature,minimum temperature,and precipitation data of 40 meteorological stations and nine monthly large-scale ocean-atmospheric circulation indices data during 1959–2019,we present an assessment of the spatial and temporal variations of extreme temperature and precipitation events in the HRB using nine extreme climate indices,and analyze the teleconnection relationship between extreme climate indices and large-scale ocean-atmospheric circulation indices.The results show that warm extreme indices show a significant(P < 0.05) increasing trend,while cold extreme indices(except for cold spell duration) and diurnal temperature range(DTR) show a significant decreasing trend.Furthermore,all extreme temperature indices show significant mutations during 1959-2019.Spatially,a stronger warming trend occurs in eastern HRB than western HRB,while maximum 5-d precipitation(Rx5day) and rainstorm days(R25) show an increasing trend in the southern,central,and northwestern regions of HRB.Arctic oscillation(AO),Atlantic multidecadal oscillation(AMO),and East Atlantic/Western Russia(EA/WR) have a stronger correlation with extreme climate indices compared to other circulation indices.AO and AMO(EA/WR) exhibit a significant(P < 0.05) negative(positive)correlation with frost days and diurnal temperature range.Extreme warm events are strongly correlated with the variability of AMO and EA/WR in most parts of HRB,while extreme cold events are closely related to the variability of AO and AMO in eastern HRB.In contrast,AMO,AO,and EA/WR show limited impacts on extreme precipitation events in most parts of HRB.展开更多
It is preliminary estimated that the proved geological reserves of original low-oil-saturation reservoirs(OLOSRs)of 54 blocks in China are more than 820 million tons.As same as the high water-cut stage of a reservoir ...It is preliminary estimated that the proved geological reserves of original low-oil-saturation reservoirs(OLOSRs)of 54 blocks in China are more than 820 million tons.As same as the high water-cut stage of a reservoir after water flooding,the initial water cut of OLOSRS is higher than 80%.The industrial application of EOR technology could efficiently enhance oil recovery rate from 8.4% to 20.1% of reservoirs after water flooding.The suitable measurements of EOR to the OLOSRs probably have a profound impact on achieving higher oilfield reserves and production.In this paper,the main characteristics and reserves potential of OLOSRs have been studied by investigations and laboratory experiments.The relationship between initial oil saturation and displacement efficiency is also analyzed.The feasibility of EOR technologies for different OLOSRs is discussed.The results show that the OLOSRs could be divided into two categories(primary and secondary)by origin of low oil saturation.The two categories contain abundant reserves in China’s major oilfields,but their occurrence states of crude oil are quite different.If the average oil saturation of the OLOSR is defined at 40%,there are 13.1%-54.2%crude oil that could be recovered by using the existing EOR technology,especially in the primary OLOSRs with low permeability and the secondary OLOSRs with high permeability.展开更多
基金Under the auspices of National Natural Science Foundation of China(No.52279016,51909106,51879108,42002247,41471160)Natural Science Foundation of Guangdong Province,China(No.2020A1515011038,2020A1515111054)+1 种基金Special Fund for Science and Technology Development in 2016 of Department of Science and Technology of Guangdong Province,China(No.2016A020223007)the Project of Jinan Science and Technology Bureau(No.2021GXRC070)。
文摘Huaihe River Basin(HRB) is located in China’s north-south climatic transition zone,which is very sensitive to global climate change.Based on the daily maximum temperature,minimum temperature,and precipitation data of 40 meteorological stations and nine monthly large-scale ocean-atmospheric circulation indices data during 1959–2019,we present an assessment of the spatial and temporal variations of extreme temperature and precipitation events in the HRB using nine extreme climate indices,and analyze the teleconnection relationship between extreme climate indices and large-scale ocean-atmospheric circulation indices.The results show that warm extreme indices show a significant(P < 0.05) increasing trend,while cold extreme indices(except for cold spell duration) and diurnal temperature range(DTR) show a significant decreasing trend.Furthermore,all extreme temperature indices show significant mutations during 1959-2019.Spatially,a stronger warming trend occurs in eastern HRB than western HRB,while maximum 5-d precipitation(Rx5day) and rainstorm days(R25) show an increasing trend in the southern,central,and northwestern regions of HRB.Arctic oscillation(AO),Atlantic multidecadal oscillation(AMO),and East Atlantic/Western Russia(EA/WR) have a stronger correlation with extreme climate indices compared to other circulation indices.AO and AMO(EA/WR) exhibit a significant(P < 0.05) negative(positive)correlation with frost days and diurnal temperature range.Extreme warm events are strongly correlated with the variability of AMO and EA/WR in most parts of HRB,while extreme cold events are closely related to the variability of AO and AMO in eastern HRB.In contrast,AMO,AO,and EA/WR show limited impacts on extreme precipitation events in most parts of HRB.
基金supported by the CNPC program of New Technologies and Methods for Oil and Gas Field Development(2016A-0903).
文摘It is preliminary estimated that the proved geological reserves of original low-oil-saturation reservoirs(OLOSRs)of 54 blocks in China are more than 820 million tons.As same as the high water-cut stage of a reservoir after water flooding,the initial water cut of OLOSRS is higher than 80%.The industrial application of EOR technology could efficiently enhance oil recovery rate from 8.4% to 20.1% of reservoirs after water flooding.The suitable measurements of EOR to the OLOSRs probably have a profound impact on achieving higher oilfield reserves and production.In this paper,the main characteristics and reserves potential of OLOSRs have been studied by investigations and laboratory experiments.The relationship between initial oil saturation and displacement efficiency is also analyzed.The feasibility of EOR technologies for different OLOSRs is discussed.The results show that the OLOSRs could be divided into two categories(primary and secondary)by origin of low oil saturation.The two categories contain abundant reserves in China’s major oilfields,but their occurrence states of crude oil are quite different.If the average oil saturation of the OLOSR is defined at 40%,there are 13.1%-54.2%crude oil that could be recovered by using the existing EOR technology,especially in the primary OLOSRs with low permeability and the secondary OLOSRs with high permeability.
