Based on the typical dissection of various onshore tight oil fields in China,the tight oil migration and accumulation mechanism and enrichment-controlling factors in continental lake basins are analyzed through nuclea...Based on the typical dissection of various onshore tight oil fields in China,the tight oil migration and accumulation mechanism and enrichment-controlling factors in continental lake basins are analyzed through nuclear magnetic resonance(NMR)displacement physical simulation and Lattice Boltzmann numerical simulation by using the samples of source rock,reservoir rock and crude oil.In continental lake basins,the dynamic forces driving hydrocarbon generation and expulsion of high-quality source rocks are the foundational power that determines the charging efficiency and accumulation effect of tight oil,the oil migration resistance is a key element that influences the charging efficiency and accumulation effect of tight oil,and the coupling of charging force with pore-throat resistance in tight reservoir controls the tight oil accumulation and sweet spot enrichment.The degree of tight oil enrichment in continental lake basins is controlled by four factors:source rock,reservoir pore-throat size,anisotropy of reservoir structure,and fractures.The high-quality source rocks control the near-source distribution of tight oil,reservoir physical properties and pore-throat size are positively correlated with the degree of tight oil enrichment,the anisotropy of reservoir structure reveals that the parallel migration rate is the highest,and intralayer fractures can improve the migration and accumulation efficiency and the oil saturation.展开更多
Based on the data of field outcrops,drilling cores,casting thin sections,well logging interpretation,oil/gas shows during drilling,and oil/gas testing results,and combined with modern salt-lake sediments in the Qingha...Based on the data of field outcrops,drilling cores,casting thin sections,well logging interpretation,oil/gas shows during drilling,and oil/gas testing results,and combined with modern salt-lake sediments in the Qinghai Lake,the Neogene saline lake beach-bars in southwestern Qaidam Basin are studied from the perspective of sedimentary characteristics,development patterns,sand control factors,and hydrocarbon accumulation characteristics.Beach-bar sand bodies are widely developed in the Neogene saline lake basin,and they are lithologically fine sandstone and siltstone,with wavy bedding,low-angle cross bedding,and lenticular-vein bedding.In view of spatial-temporal distribution,the beach-bar sand bodies are stacked in multiple stages vertically,migratory laterally,and extensive and continuous in NW-SE trending pattern in the plane.The stacking area of the Neogene beach-bar sandstone is predicted to be 3000 km^(2).The water salinity affects the sedimentation rate and offshore distance of beach-bar sandstone,and the debris input from the source area affects the scale and enrichment of beach-bar sandstone.The ancient landform controls the morphology and stacking style of beach-bar sandstone,and the northwest monsoon driving effect controls the long-axis extension direction of beach-bar sandstone.The beach-bars have a reservoir-forming feature of“one reservoir in one sand body”,with thick beach-bar sand bodies controlling the effective reservoir distribution and oil-source faults controlling the oil/gas migration and accumulation direction.Three favorable exploration target zones in Zhahaquan,Yingdong-eastern Wunan and Huatugou areas are proposed based on the analysis of reservoir-forming elements.展开更多
The bedrock weathered crust in front of the Altun Mountains in the Qaidam Basin,western China,is different from others because this is a salt-lake basin,where saline water fluid infiltrates and is deposited in the ove...The bedrock weathered crust in front of the Altun Mountains in the Qaidam Basin,western China,is different from others because this is a salt-lake basin,where saline water fluid infiltrates and is deposited in the overlying strata.A large amount of gypsum infills the bedrock weathered crust,and this has changed the pore structure.Using core observation,polarized light microscopy,electron probe,physical property analysis and field emission scanning electron microscopy experiments,the characteristics of the weathered bedrock have been studied.There are cracks and a small number of dissolved pores in the interior of the weathered crust.Matrix micropores are widely developed,especially the various matrix cracks formed by tectonics and weathering,as well as the stress characteristics of small dissolved pores,and physical properties such as porosity and permeability.This‘dual structure’developed in the bedrock is important for guiding the exploration of the lake basin bedrock for natural gas.展开更多
The Qaidam Basin(QB)is a concentrated distribution area and chemical industrial bases of salt lakes in China.Lakes in the QB have been expanding during the past 20 years.Rapid lake expansion resulted in some considera...The Qaidam Basin(QB)is a concentrated distribution area and chemical industrial bases of salt lakes in China.Lakes in the QB have been expanding during the past 20 years.Rapid lake expansion resulted in some considerable scientific issues on the protection of salt lake resources and infrastructure,and monitoring of hydrological processes at the lake-basin scale.Although the spatial-temporal trends of lake changes on the Qinghai-Tibet Plateau(QTP)have been well documented,the underlying influencing mechanism and hydrogeological implications of rapid lake changes in the QB are not well understood.Three lakes in the northern QB were selected to investigate lake water level fluctuations on different time scales based on extensive in-situ monitoring and satellite observations.The influencing mechanism and hydrogeological implications of rapid changes of terminal lakes were discussed in combination with the reported increasing precipitation rate and mass balance of glaciers in the northern QTP.Results reveal the following:(1)the fluctuation pattern of Sugan Lake was asynchronous and out of phase with that of Xiao Qaidam and Toson lakes during the monitoring period;(2)Sugan Lake water rose gradually,and the rise interval was from late April to early July.In contrast,Xiao Qaidam and Toson lakes took on a rapid and steep rise,and the rise intervalwas from late July to September;(3)the influencing mechanisms for rapid lake fluctuations are controlled by different factors:glacier and snow melting with increasing temperature for Sugan Lake and increasing precipitation for Xiao Qaidam and Toson lakes;(4)in accordance with different intervals and influencing mechanisms of rapid lake expansions in the QB,hydrological risk precaution of lakes and corresponding river catchments was conducted in different parts of the basin.This study provided an important scientific basis for assessing the hydrological process and hydrological risk precaution,and protection of salt lake resources along with rapid lake expansions in the arid area.展开更多
In the face of global warming and increasing impervious surfaces,quantifying the change of climate potential productivity(CPP)is of great significance for the food production planning.Targeting the Dongting Lake Basin...In the face of global warming and increasing impervious surfaces,quantifying the change of climate potential productivity(CPP)is of great significance for the food production planning.Targeting the Dongting Lake Basin,which is a key area for food production in China,this paper uses meteorological data,as well as Climate Change Initiative Land Cover,and Shuttle Radar Topography Mission digital elevation model to investigate the CPP and its changes from 2000 to 2020.The suitability of land for cultivation(SLC),and the land use/land cover change(LUCC)are also considered.The results showed that the CPP varied from 9,825 to 20,895 kg ha^(-1).Even though the newly added impervious surfaces indirectly resulted in the decrease of CPP by of 9.81×10~8 kg,overall,the CPP increased at an average rate of 83.7 kg ha^(-1)a^(-1).Global warming is the strongest driver behind CPP increase,and CPP has played an important role in the conversions between cultivated land and other land types.The structure of land types tends to be optimized against this challenge.展开更多
Changes in the weather will cause variations in the hydrological system.Arid areas,with fragile hydrological systems,are very sensitive to changes in the weather,so the coupling analysis of short-term weather and runo...Changes in the weather will cause variations in the hydrological system.Arid areas,with fragile hydrological systems,are very sensitive to changes in the weather,so the coupling analysis of short-term weather and runoff in arid areas is of great significance.The Daihai Lake is a closed inland lake in an arid area of China.In this paper,Weather Research and Forecasting model mode-Hydrological module(WRF-HYDRO)is used to simulate the coupling of weather and hydrology in the Daihai Lake Basin.Regional optimization of WRF-HYDRO is carried out to determine the optimal parameters.The optimal WRF-HYDRO model is applied to couple the short-term weather and runoff in the Daihai Lake Basin to reproduce several rainstorm and flood events.It is found that runoff infiltration parameter(REFKDT)in WRF-HYDRO is the parameter that has the most severe effect on runoff in the Daihai Lake Basin.WRF-HYDRO can capture the rainstorm moment of the rainstorm events in the Daihai Lake Basin,especially the first rainstorm moment,and its simulation accuracy is good.WRF-HYDRO has a strong ability to capture flood peak,but there is a discrepancy between WRF-HYDRO flood peak and Soil Conservation Service Curve Number(SCS-CN)calculation result at the flood peak moment.The northern part of Zuoyun County should guard against the occurrence of flood disaster in wet season.The coupling of weatherand hydrology can not only make up for the lack of runoff data in arid basins,but also provide a basis for water resources management and disaster prevention and mitigation in the basins.展开更多
The Qarhan Salt Lake area is the Quaternary depocenter of the Qaidam Basin, and carries thick lacustrine sediments, as well as rich potassium and magnesium salt deposits. The abundant resources and thick sediments in ...The Qarhan Salt Lake area is the Quaternary depocenter of the Qaidam Basin, and carries thick lacustrine sediments, as well as rich potassium and magnesium salt deposits. The abundant resources and thick sediments in this lake provide an ideal place for the study of biogas formation and preservation, salt lake evolution, and the uplift of the Tibetan Plateau. In this study, we attempt to construct a paleomagnetic and ^(230)Th age model and to obtain information on tectonic activity and salt lake evolution through detailed studies on a 1300-m-long drill core(15DZK01) from the northwestern margin of the Qarhan Salt Lake area(Dongling Lake). Based on gypsum ^(230)Th dating, the age of the uppermost clastic deposit was calculated to be around 0.052 Ma. The polarity sequence consist of 13 pairs of normal and reversed zones,which can be correlated with subchrons C2r.1r-C1n of the geomagnetic polarity timescale(GPTS 2012)(from ~2.070 Ma to ~0.052 Ma). Sedimentary characteristics indicate that Dongling Lake witnessed freshwater environment between ~ 2.070 Ma and 1.546 Ma. During this period, the sedimentary record reflects primarily lakeshore, shallow-water and swamp environments, representing favourable conditions for the formation of hydrocarbon source rocks. Between 1.546 Ma and ~ 0.052 Ma, the Dongling Lake was in sulphate deposition stage, which contrasts with the central Qarhan Salt Lake area, where this stage did not occur in the meantime. During this stage, Dongling Lake was in a shallow saltwater lake environment, but several periods of reduced salinity occurred during this stage. During the late Pleistocene at ~0.052 Ma, the Dongling Lake experienced uplift due to tectonic activity, and saltwater migrated through the Sanhu Fault to the central Qarhan Salt Lake area, resulting in the absence of halite deposition stage. The residual saline water was concentrated into magnesium-rich brine due to the lack of freshwater, and few potassium salt deposits occur in the Dongling Lake area.展开更多
Water supply services(WSSs) are critical for the regional water balance and water circulation, but relevant studies have not established the relationship between WSSs and human well-being. This research identifies the...Water supply services(WSSs) are critical for the regional water balance and water circulation, but relevant studies have not established the relationship between WSSs and human well-being. This research identifies the scope of areas that benefit from WSSs from an ecosystem service flow perspective. Moreover, the path and quantity of the flow of WSSs are simulated to provide a scientific theoretical basis for ecosystem service management and ecological compensation. The Dongjiang Lake Basin is a national priority river basin in China where ecological compensation pilot programmes concerning water resources are top priorities. Dongjiang Lake Basin experienced an increase and then a decrease in the overall supply of water, with an average net water supply of 1096–1500 mm for the years 1995, 2000, 2005 and 2010. The water demand increased each year in service beneficiary areas(SBAs), varying from 387 to 580 mm. Overall, Dongjiang Lake Basin met the net water demands of the actual SBAs in the lower reaches, but a gap in the water supply and demand emerged gradually. This research provides an understanding of the functional mechanisms for the provision, demand and flow of WSSs and provides a scientific theoretical basis for ecosystem service management and ecological compensation.展开更多
Glacier is a common sensitivity indicator of environmental and global climate change.Examining the relationship between glacier area and climate change will help reveal glacier change mechanisms and future trends.Glac...Glacier is a common sensitivity indicator of environmental and global climate change.Examining the relationship between glacier area and climate change will help reveal glacier change mechanisms and future trends.Glacier changes are also of great significance to the regulation of regional water resources.This study selected the Hala Lake Basin in the northeastern Qinhai-Tibet Plateau as a study area,and examined the relationships between the temporal and spatial change of glaciers in the northeastern Qinghai-Tibet Plateau and climate change based on remote sensing imagery,climatological data,and topographic data during the past 30 years.Results showed that glacier area in the Hala Lake basin fluctuated and decreased from106.24 km2 in 1986 to 78.84 km2 in 2015,with a decreasing rate of 0.94 km2·yr-1.The number of glacier patches,mean patch area,and largest patch index all decreased from 1986 to 2015,while the splitting index increased from 1986 to 2015,indicating that the landscape fragmentation of glacier in the Hala Lake Basin was increasing significantly during the study period.Glacier area change was mainly concentrated in the slopes>25°with an altitude of 4500-5000 m,and the retreating rate of glacier of sunny slope was obviously higher than that of shady slope.Geometric center of glacier in the basin moved from southwest to northeast towards high altitude.Results of the response of glacier extent to climate change showed that temperature was the dominant factor affecting glacier area dynamic change in the Hala Lake Basin.It is predicted that in future several years,the glacier area will decrease and fragment continually as a result of global warming on the Tibetan Plateau.展开更多
Qaidam basin is an important part of National Key Development Area–Lanzhou-Xining Area,is a key region of resource development in Western Development,is a National Circular Economy Pilot Zone.The focus
Based on Kunming statistical yearbook and field survey data of agricultural non-point source pollution in counties or districts in the Dianchi Lake basin,previous and current situation of agricultural production and a...Based on Kunming statistical yearbook and field survey data of agricultural non-point source pollution in counties or districts in the Dianchi Lake basin,previous and current situation of agricultural production and agricultural non-point source pollution control in the Dianchi Lake basin were studied,and countermeasures and suggestions of comprehensive control of agricultural non-point source pollution in the basin were proposed.展开更多
The Tai and Chao Lake basins are currently facing a serious water pollution crisis associated with the absence of an effective environmental governance system. The water pollution and the water governance system of th...The Tai and Chao Lake basins are currently facing a serious water pollution crisis associated with the absence of an effective environmental governance system. The water pollution and the water governance system of the two basins will be compared. The reasons for water pollution in both basins are similar, namely the weak current water environmental governance system cannot deal with the consequences of the rapidly growing economy. China’s water governance system is a complicated combination of basin management with both departmental management and regional management. There is an absence of legal support and sound coordination mechanisms, resulting in fragmented management practices in the existing water environmental governance system. A comparison is made for the Tai and Chao Lake basins and Canada, France, the United Kingdom and the United States. Based on China’s present central-local governance structure and departmental system, an integrated reform of basin level and water environmental governance in China should learn from international experiences. The reforms could consist of improved governance structures, rebuilding authoritative and powerful agencies for basin management, strengthening the organizational structure of the basin administrations, improving legislation and regulatory systems for basin management and enhancing public participation mechanisms.展开更多
The Sugan Lake Basin is located in the inland arid region of northwestern China,in which groundwater is of great significance to human and ecology.Therefore,it is necessary to understand the chemical characteristics a...The Sugan Lake Basin is located in the inland arid region of northwestern China,in which groundwater is of great significance to human and ecology.Therefore,it is necessary to understand the chemical characteristics and quality of groundwater in the basin.Based on samples collected from 35 groundwater wells in Sugan Lake Basin,the spatial distribution characteristics of groundwater chemistry,main hydrogeochemical processes and groundwater quality have been discussed in this paper by using the multivariate statistics and hydrochemistry analysis methods.The results showed that the groundwater is weakly alkaline,and its total dissolved solid(TDS)and total hardness(TH) are high,with the average values of 1244.03 mg/L and 492.10 mg/L,respectively.The types of groundwater are mainly HCO_3^--SO_4^(2-)-Ca^(2+)type in the runoff area and Cl^--SO_4^(2-)-Na^+type in the catchment area.Rock weathering and ion exchange are the main controlling factors of regional groundwater chemistry,followed by evaporative crystallization,and human activities have less impact on groundwater.The spatial difference of groundwater quality is obvious,the water quality of the catchment area is not suitable for drinking,and the suitability for plant growth is also poor.The groundwater in the runoff area can be used for drinking,but the hardness is slightly higher,which is more suitable for ecological purpose.展开更多
Changing climatic conditions and extensive human activities have influenced the global water cycle.In recent years,significant changes in climate and land use have degraded the watershed ecosystem of the Ebinur Lake B...Changing climatic conditions and extensive human activities have influenced the global water cycle.In recent years,significant changes in climate and land use have degraded the watershed ecosystem of the Ebinur Lake Basin in Xinjiang,Northwest China.In this paper,variations of runoff,temperature,precipitation,reference evapotranspiration,lake area,socio-economic water usage,groundwater level and water quality in the Ebinur Lake Basin from 1961 to 2015 were systematically analyzed by the Mann-Kendall test methods(M-K)mutation test,the cumulative levelling method,the climate-sensitive method and land-use change index.In addition,we evaluated the effects of human activities on land use change and water quality.The results reveal that there was a significant increase in temperature and precipitation from 1961 to 2015,despite a decrease in reference evapotranspiration.The Wenquan station was not significantly affected by human activities as it is situated at a higher altitude.Runoff at this station increased significantly with climate warming.In contrast,runoff at the Jinghe station was severely affected by numerous human activities.Runoff decreased without obvious fluctuations.The contributions of climate change to runoff variation at the Jinghe and Wenquan stations were 46.87%and 58.94%,respectively;and the contributions of human activities were 53.13%and 41.06%,respectively.Land-use patterns in the basin have changed significantly between 1990 and 2015:urban and rural constructed lands,saline-alkali land,bare land,cultivated land,and forest land have expanded,while areas under grassland,lake,ice/snow and river/channel have declined.Human activities have dramatically intensified land degradation and desertification.From 1961 to 2015,both the inflow into the Ebinur Lake and the area of the lake have declined year by year;groundwater levels have dropped significantly,and the water quality has deteriorated during the study period.In the oasis irrigation area below the runoff pass,human activities mainly influenced the utilization mode and quantity of water resources.Changes in the hydrology and quantity of water resources were driven primarily by the continuous expansion of cultivated land and oasis,as well as the growth of population and the construction of hydraulic engineering projects.After 2015,the effects of some ecological protection projects were observed.However,there was no obvious sign of ecological improvement in the basin,and some environmental problems continue to persist.On this basis,this study recommends that the expansion of oasis should be limited according to the carrying capacity of the local water bodies.Moreover,in order to ensure the ecological security of the basin,it is necessary to determine the optimal oasis area for sustainable development and improve the efficiency of water resources exploitation and utilization.展开更多
The Quaternary was the main evaporite deposition period in the Qaidam Basin(QB), but the correlation between the evaporite deposition period and the glacial period is still unclear. In this study, the research objects...The Quaternary was the main evaporite deposition period in the Qaidam Basin(QB), but the correlation between the evaporite deposition period and the glacial period is still unclear. In this study, the research objects are primarily evaporite-bearing strata in a 461.58 m-long drill core in the QB. X-ray powder diffraction(XRD) and scanning electron microscopy(SEM) were applied to study the evaporite minerals, U-Th dating being applied to construct the ~(230)Th geochronological framework. Evaporite deposition from Marine Isotope Stage(MIS) 15 to MIS 4 in the borehole was reconstructed via mineralogical and geochronological data. The evaporite minerals are mainly halite(NaCl), mirabilite(Na_(2)SO_(4)·10H_(2)O), thenardite(Na_(2)SO_(4)) and gypsum(CaSO_(4)·2H_(2)O). A total of 9 effective ~(230)Th data points, ranging from 492.5 ± 43.0 ka to 62.0 ± 11.9 ka, were obtained. The depositional age of the earliest halite layer in the borehole is 592.5–563.0 ka. There were mirabilite deposits in the QB during the cold glacial environment of MIS 6. During MIS 4, the study area desiccated, with mirabilite and halite being deposited. This study suggests that mirabilite is an indicator mineral for the glacial environment in the QB, while halite deposition does not correspond well to glaciation.展开更多
Objective A total of 820 million tons of potash reserves are predicted to exist in the Palaeocene–Eocene of the Jianghan Basin.However,the basin history is still unclear concerning the potash enriching conditions and...Objective A total of 820 million tons of potash reserves are predicted to exist in the Palaeocene–Eocene of the Jianghan Basin.However,the basin history is still unclear concerning the potash enriching conditions and mechanism.The Well SKD1 is the first exploration well drilled in the Paleogene of Jianghan Basin with continuous coring,which was implemented in the展开更多
The purpose of this paper is to present a brief concept of the ecological and environmental water demand of lake. The present situation and affecting factors of lake ecological system in the Haihe\|Luanhe Basin of Nor...The purpose of this paper is to present a brief concept of the ecological and environmental water demand of lake. The present situation and affecting factors of lake ecological system in the Haihe\|Luanhe Basin of North China was analyzed. The calculating method of the ecological and environmental water demand of the lake basis on the water body and the calculating method of the ecological and environmental water demand of the lake basis on the aquatic ecosystem, wetland and vegetation were compared and discussed. As the examples of Baiyangdian Lake and Beidagang Lake in Haihe\|Luanhe river basin, the ecological and environmental water demand of the two lakes was calculated to be 27×10\+8m\+3. It is 6.75 times to the water demand according to the calculating method of the ecological and environmental water demand of the lake basis on the water body. The research result indicated: (1) The calculating methods of the ecological and environmental water demand of the lake basis on the aquatic ecosystem should be better than only basis on the water body of lake. (2) The data, such as area of the vegetation kind around and in the lake, the vegetation coefficient, the evaporating amount of the vegetation and the vegetation water demand itself around and in the lake are lack and urgent need. Some suggestions for controlling and regulating the water resource of the lake in North China were proposed.展开更多
The need for effective and efficient monitoring, evaluation and control of water quality in Lake Victoria Basin (LVB) has become more demanding in this era of urbanization, population growth and climate change and var...The need for effective and efficient monitoring, evaluation and control of water quality in Lake Victoria Basin (LVB) has become more demanding in this era of urbanization, population growth and climate change and variability. Traditional methods that rely on collecting water samples, testing and analyses in water laboratories are not only costly but also lack capability for real-time data capture, analyses and fast dissemination of information to relevant stakeholders for making timely and informed decisions. In this paper, a Water Sensor Network (WSN) system prototype developed for water quality monitoring in LVB is presented. The development was preceded by evaluation of prevailing environment including availability of cellular network coverage at the site of operation. The system consists of an Arduino microcontroller, water quality sensors, and a wireless network connection module. It detects water temperature, dissolved oxygen, pH, and electrical conductivity in real-time and disseminates the information in graphical and tabular formats to relevant stakeholders through a web-based portal and mobile phone platforms. The experimental results show that the system has great prospect and can be used to operate in real world environment for optimum control and protection of water resources by providing key actors with relevant and timely information to facilitate quick action taking.展开更多
The typical regions of the Taihu Lake Basin,China,were selected to analyze the variation characteristics of river-lake networks under intensive human activities.The characteristics of the fractal dimension of river ne...The typical regions of the Taihu Lake Basin,China,were selected to analyze the variation characteristics of river-lake networks under intensive human activities.The characteristics of the fractal dimension of river networks and lakes for different periods were investigated and the influences of river system evolution on water level changes were further explored through the comparison of their fractal characters.The results are as follows:1) River network development of the study area is becoming more monotonous and more simple;the number of lakes is reducing significantly,and the water surface ratio has dropped significantly since the 1980s.2) The box dimension of the river networks in all the cities of the study area decreased slowly from the 1960s to the 1980s,while the decrease was significant from the 1980s to the 2000s.The variations of lake correlation dimension are similar to those of the river network box dimensions.This is unfavorable for the storage capacity of the river networks and lakes.3) The Hurst exponents of water levels were all between 0.5 and 1.0 from the 1960s to the 1980s,while decreased in the 2000s,indicating the decline in persistence and increase in the complexity of water level series.The paper draws a conclusion that the relationship between the fractal dimension of river-lake networks and the Hurst exponents of the water level series can reveal the impacts of river system changes on flood disasters to some extent:the disappearance of river networks and lakes will increase the possibility of flood occurrence.展开更多
基金Supported by the National Science and Technology Major Project of China(2016ZX05046-001).
文摘Based on the typical dissection of various onshore tight oil fields in China,the tight oil migration and accumulation mechanism and enrichment-controlling factors in continental lake basins are analyzed through nuclear magnetic resonance(NMR)displacement physical simulation and Lattice Boltzmann numerical simulation by using the samples of source rock,reservoir rock and crude oil.In continental lake basins,the dynamic forces driving hydrocarbon generation and expulsion of high-quality source rocks are the foundational power that determines the charging efficiency and accumulation effect of tight oil,the oil migration resistance is a key element that influences the charging efficiency and accumulation effect of tight oil,and the coupling of charging force with pore-throat resistance in tight reservoir controls the tight oil accumulation and sweet spot enrichment.The degree of tight oil enrichment in continental lake basins is controlled by four factors:source rock,reservoir pore-throat size,anisotropy of reservoir structure,and fractures.The high-quality source rocks control the near-source distribution of tight oil,reservoir physical properties and pore-throat size are positively correlated with the degree of tight oil enrichment,the anisotropy of reservoir structure reveals that the parallel migration rate is the highest,and intralayer fractures can improve the migration and accumulation efficiency and the oil saturation.
基金supported by the Chinese National Natural Science Fund Project(41072084)National Program on Key Basic Research Project(973 Program)(No. 2009CB219502-3)Prof.Qiu Yinan at RIPED(Research Institute for Petroleum Exploration and Development) of CNPC(China National Petroleum Corporation) for his belief in this work and financial support of the research
基金Supported by the PetroChina Science and Technology Project (2021DJ0402,2021DJ0202)。
文摘Based on the data of field outcrops,drilling cores,casting thin sections,well logging interpretation,oil/gas shows during drilling,and oil/gas testing results,and combined with modern salt-lake sediments in the Qinghai Lake,the Neogene saline lake beach-bars in southwestern Qaidam Basin are studied from the perspective of sedimentary characteristics,development patterns,sand control factors,and hydrocarbon accumulation characteristics.Beach-bar sand bodies are widely developed in the Neogene saline lake basin,and they are lithologically fine sandstone and siltstone,with wavy bedding,low-angle cross bedding,and lenticular-vein bedding.In view of spatial-temporal distribution,the beach-bar sand bodies are stacked in multiple stages vertically,migratory laterally,and extensive and continuous in NW-SE trending pattern in the plane.The stacking area of the Neogene beach-bar sandstone is predicted to be 3000 km^(2).The water salinity affects the sedimentation rate and offshore distance of beach-bar sandstone,and the debris input from the source area affects the scale and enrichment of beach-bar sandstone.The ancient landform controls the morphology and stacking style of beach-bar sandstone,and the northwest monsoon driving effect controls the long-axis extension direction of beach-bar sandstone.The beach-bars have a reservoir-forming feature of“one reservoir in one sand body”,with thick beach-bar sand bodies controlling the effective reservoir distribution and oil-source faults controlling the oil/gas migration and accumulation direction.Three favorable exploration target zones in Zhahaquan,Yingdong-eastern Wunan and Huatugou areas are proposed based on the analysis of reservoir-forming elements.
基金the National Major Project of Science and Technology in developing great oil&gas field and coal bed gas(Grant No.2016ZX05007-006)the Study on water-cut control and production stabilization in the old gasfields and efficient development in new gasfields in Qaidam Basin(Grant No.2016E-0106GF)。
文摘The bedrock weathered crust in front of the Altun Mountains in the Qaidam Basin,western China,is different from others because this is a salt-lake basin,where saline water fluid infiltrates and is deposited in the overlying strata.A large amount of gypsum infills the bedrock weathered crust,and this has changed the pore structure.Using core observation,polarized light microscopy,electron probe,physical property analysis and field emission scanning electron microscopy experiments,the characteristics of the weathered bedrock have been studied.There are cracks and a small number of dissolved pores in the interior of the weathered crust.Matrix micropores are widely developed,especially the various matrix cracks formed by tectonics and weathering,as well as the stress characteristics of small dissolved pores,and physical properties such as porosity and permeability.This‘dual structure’developed in the bedrock is important for guiding the exploration of the lake basin bedrock for natural gas.
基金Supported by the Second Tibetan Plateau Scientific Expedition and Research Program(No.2019 QZKK 0805)the National Natural Science Foundation of China(No.U 21 A 2018)the Foundation of Department of Qinghai Science&Technology(No.2020-ZJ-T 06)。
文摘The Qaidam Basin(QB)is a concentrated distribution area and chemical industrial bases of salt lakes in China.Lakes in the QB have been expanding during the past 20 years.Rapid lake expansion resulted in some considerable scientific issues on the protection of salt lake resources and infrastructure,and monitoring of hydrological processes at the lake-basin scale.Although the spatial-temporal trends of lake changes on the Qinghai-Tibet Plateau(QTP)have been well documented,the underlying influencing mechanism and hydrogeological implications of rapid lake changes in the QB are not well understood.Three lakes in the northern QB were selected to investigate lake water level fluctuations on different time scales based on extensive in-situ monitoring and satellite observations.The influencing mechanism and hydrogeological implications of rapid changes of terminal lakes were discussed in combination with the reported increasing precipitation rate and mass balance of glaciers in the northern QTP.Results reveal the following:(1)the fluctuation pattern of Sugan Lake was asynchronous and out of phase with that of Xiao Qaidam and Toson lakes during the monitoring period;(2)Sugan Lake water rose gradually,and the rise interval was from late April to early July.In contrast,Xiao Qaidam and Toson lakes took on a rapid and steep rise,and the rise intervalwas from late July to September;(3)the influencing mechanisms for rapid lake fluctuations are controlled by different factors:glacier and snow melting with increasing temperature for Sugan Lake and increasing precipitation for Xiao Qaidam and Toson lakes;(4)in accordance with different intervals and influencing mechanisms of rapid lake expansions in the QB,hydrological risk precaution of lakes and corresponding river catchments was conducted in different parts of the basin.This study provided an important scientific basis for assessing the hydrological process and hydrological risk precaution,and protection of salt lake resources along with rapid lake expansions in the arid area.
基金funded by the National Natural Science Foundation of China(Grant No.72174211)the Natural Science Foundation of Hunan Province(Grant No.2023JJ30693)。
文摘In the face of global warming and increasing impervious surfaces,quantifying the change of climate potential productivity(CPP)is of great significance for the food production planning.Targeting the Dongting Lake Basin,which is a key area for food production in China,this paper uses meteorological data,as well as Climate Change Initiative Land Cover,and Shuttle Radar Topography Mission digital elevation model to investigate the CPP and its changes from 2000 to 2020.The suitability of land for cultivation(SLC),and the land use/land cover change(LUCC)are also considered.The results showed that the CPP varied from 9,825 to 20,895 kg ha^(-1).Even though the newly added impervious surfaces indirectly resulted in the decrease of CPP by of 9.81×10~8 kg,overall,the CPP increased at an average rate of 83.7 kg ha^(-1)a^(-1).Global warming is the strongest driver behind CPP increase,and CPP has played an important role in the conversions between cultivated land and other land types.The structure of land types tends to be optimized against this challenge.
基金This project is supported by the Major Science and Technology Project of Inner Mongolia Autonomous Region of China(ZDZX2018054)the National Natural Science Foundation of China(42067013).
文摘Changes in the weather will cause variations in the hydrological system.Arid areas,with fragile hydrological systems,are very sensitive to changes in the weather,so the coupling analysis of short-term weather and runoff in arid areas is of great significance.The Daihai Lake is a closed inland lake in an arid area of China.In this paper,Weather Research and Forecasting model mode-Hydrological module(WRF-HYDRO)is used to simulate the coupling of weather and hydrology in the Daihai Lake Basin.Regional optimization of WRF-HYDRO is carried out to determine the optimal parameters.The optimal WRF-HYDRO model is applied to couple the short-term weather and runoff in the Daihai Lake Basin to reproduce several rainstorm and flood events.It is found that runoff infiltration parameter(REFKDT)in WRF-HYDRO is the parameter that has the most severe effect on runoff in the Daihai Lake Basin.WRF-HYDRO can capture the rainstorm moment of the rainstorm events in the Daihai Lake Basin,especially the first rainstorm moment,and its simulation accuracy is good.WRF-HYDRO has a strong ability to capture flood peak,but there is a discrepancy between WRF-HYDRO flood peak and Soil Conservation Service Curve Number(SCS-CN)calculation result at the flood peak moment.The northern part of Zuoyun County should guard against the occurrence of flood disaster in wet season.The coupling of weatherand hydrology can not only make up for the lack of runoff data in arid basins,but also provide a basis for water resources management and disaster prevention and mitigation in the basins.
基金co-supported by the Geological Survey Project of China(Grant No. 1212331413023)the National Natural Science Foundation of China(Grant No. U1407207)
文摘The Qarhan Salt Lake area is the Quaternary depocenter of the Qaidam Basin, and carries thick lacustrine sediments, as well as rich potassium and magnesium salt deposits. The abundant resources and thick sediments in this lake provide an ideal place for the study of biogas formation and preservation, salt lake evolution, and the uplift of the Tibetan Plateau. In this study, we attempt to construct a paleomagnetic and ^(230)Th age model and to obtain information on tectonic activity and salt lake evolution through detailed studies on a 1300-m-long drill core(15DZK01) from the northwestern margin of the Qarhan Salt Lake area(Dongling Lake). Based on gypsum ^(230)Th dating, the age of the uppermost clastic deposit was calculated to be around 0.052 Ma. The polarity sequence consist of 13 pairs of normal and reversed zones,which can be correlated with subchrons C2r.1r-C1n of the geomagnetic polarity timescale(GPTS 2012)(from ~2.070 Ma to ~0.052 Ma). Sedimentary characteristics indicate that Dongling Lake witnessed freshwater environment between ~ 2.070 Ma and 1.546 Ma. During this period, the sedimentary record reflects primarily lakeshore, shallow-water and swamp environments, representing favourable conditions for the formation of hydrocarbon source rocks. Between 1.546 Ma and ~ 0.052 Ma, the Dongling Lake was in sulphate deposition stage, which contrasts with the central Qarhan Salt Lake area, where this stage did not occur in the meantime. During this stage, Dongling Lake was in a shallow saltwater lake environment, but several periods of reduced salinity occurred during this stage. During the late Pleistocene at ~0.052 Ma, the Dongling Lake experienced uplift due to tectonic activity, and saltwater migrated through the Sanhu Fault to the central Qarhan Salt Lake area, resulting in the absence of halite deposition stage. The residual saline water was concentrated into magnesium-rich brine due to the lack of freshwater, and few potassium salt deposits occur in the Dongling Lake area.
基金Under the auspices of National Key Research and Development Program of China(No.2016YFC0503706 2016YFC0503403)+1 种基金National Natural Science Foundation of China(No.31400411)Technical Support Program of the Ministry of Science and Technology of China(No.2013BAC03B05)
文摘Water supply services(WSSs) are critical for the regional water balance and water circulation, but relevant studies have not established the relationship between WSSs and human well-being. This research identifies the scope of areas that benefit from WSSs from an ecosystem service flow perspective. Moreover, the path and quantity of the flow of WSSs are simulated to provide a scientific theoretical basis for ecosystem service management and ecological compensation. The Dongjiang Lake Basin is a national priority river basin in China where ecological compensation pilot programmes concerning water resources are top priorities. Dongjiang Lake Basin experienced an increase and then a decrease in the overall supply of water, with an average net water supply of 1096–1500 mm for the years 1995, 2000, 2005 and 2010. The water demand increased each year in service beneficiary areas(SBAs), varying from 387 to 580 mm. Overall, Dongjiang Lake Basin met the net water demands of the actual SBAs in the lower reaches, but a gap in the water supply and demand emerged gradually. This research provides an understanding of the functional mechanisms for the provision, demand and flow of WSSs and provides a scientific theoretical basis for ecosystem service management and ecological compensation.
基金supported by the National Science Foundation of China (41730854, 41877157, 41530854)the Project supported by State Key Laboratory of Loess and Quaternary Geology (SKLLQG1604)+2 种基金the Project supported by State Key Laboratory of Earth Surface Processes and Resource Ecology (2017-KF-15)the Project of Shandong Province Higher Educational Science and Technology Program (J17KA192)the National Key Research and Development Plan of Shandong Province (2018GSF117021)
文摘Glacier is a common sensitivity indicator of environmental and global climate change.Examining the relationship between glacier area and climate change will help reveal glacier change mechanisms and future trends.Glacier changes are also of great significance to the regulation of regional water resources.This study selected the Hala Lake Basin in the northeastern Qinhai-Tibet Plateau as a study area,and examined the relationships between the temporal and spatial change of glaciers in the northeastern Qinghai-Tibet Plateau and climate change based on remote sensing imagery,climatological data,and topographic data during the past 30 years.Results showed that glacier area in the Hala Lake basin fluctuated and decreased from106.24 km2 in 1986 to 78.84 km2 in 2015,with a decreasing rate of 0.94 km2·yr-1.The number of glacier patches,mean patch area,and largest patch index all decreased from 1986 to 2015,while the splitting index increased from 1986 to 2015,indicating that the landscape fragmentation of glacier in the Hala Lake Basin was increasing significantly during the study period.Glacier area change was mainly concentrated in the slopes>25°with an altitude of 4500-5000 m,and the retreating rate of glacier of sunny slope was obviously higher than that of shady slope.Geometric center of glacier in the basin moved from southwest to northeast towards high altitude.Results of the response of glacier extent to climate change showed that temperature was the dominant factor affecting glacier area dynamic change in the Hala Lake Basin.It is predicted that in future several years,the glacier area will decrease and fragment continually as a result of global warming on the Tibetan Plateau.
基金sponsored by China Academy of Engineering Major Consulting Project (No: 2012-ZD-14)
文摘Qaidam basin is an important part of National Key Development Area–Lanzhou-Xining Area,is a key region of resource development in Western Development,is a National Circular Economy Pilot Zone.The focus
基金Supported by Research on the Comprehensive Control Measures of Agricultural Non-point Source Pollution in the Dianchi Lake Basin Funded by Kunming Agricultural Bureau(2016JC01)Project of Yunnan Engineering Research Center for Urban Characteristic Agriculture(TSNY0201)+7 种基金Scientific Research Foundation of Yunnan Department of Education(2014Y390)Application Base Research Project for Young Scholars of Yunnan Province(2013FD040)Talent Introduction Project of Kunming University(YJL14005)Talent Introduction Foundation of Kunming University(YJL12010)Key Foundation of Kunming University(XJL12020)Scientific Research Project for Undergraduates of Kunming University(XJD16081)Research on the Ecology and Rational Distribution of Main Cultivars in Producing Areas of Raw Materials of China Tobacco in Yunnan ProvinceProject of Construction of the Dominant Key Subject(Ecology)in Universities and Colleges in Yunnan Province(05000511311)
文摘Based on Kunming statistical yearbook and field survey data of agricultural non-point source pollution in counties or districts in the Dianchi Lake basin,previous and current situation of agricultural production and agricultural non-point source pollution control in the Dianchi Lake basin were studied,and countermeasures and suggestions of comprehensive control of agricultural non-point source pollution in the basin were proposed.
文摘The Tai and Chao Lake basins are currently facing a serious water pollution crisis associated with the absence of an effective environmental governance system. The water pollution and the water governance system of the two basins will be compared. The reasons for water pollution in both basins are similar, namely the weak current water environmental governance system cannot deal with the consequences of the rapidly growing economy. China’s water governance system is a complicated combination of basin management with both departmental management and regional management. There is an absence of legal support and sound coordination mechanisms, resulting in fragmented management practices in the existing water environmental governance system. A comparison is made for the Tai and Chao Lake basins and Canada, France, the United Kingdom and the United States. Based on China’s present central-local governance structure and departmental system, an integrated reform of basin level and water environmental governance in China should learn from international experiences. The reforms could consist of improved governance structures, rebuilding authoritative and powerful agencies for basin management, strengthening the organizational structure of the basin administrations, improving legislation and regulatory systems for basin management and enhancing public participation mechanisms.
基金financially supported by National Natural Science Foundation of China(41761047,41661005,41661084,41861009 and 41261104)National Natural Science Foundation innovation research group science foundation of China(41421061)Autonomous project of State Key Laboratory of Cryosphere Sciences(SKLCS-ZZ-2017)
文摘The Sugan Lake Basin is located in the inland arid region of northwestern China,in which groundwater is of great significance to human and ecology.Therefore,it is necessary to understand the chemical characteristics and quality of groundwater in the basin.Based on samples collected from 35 groundwater wells in Sugan Lake Basin,the spatial distribution characteristics of groundwater chemistry,main hydrogeochemical processes and groundwater quality have been discussed in this paper by using the multivariate statistics and hydrochemistry analysis methods.The results showed that the groundwater is weakly alkaline,and its total dissolved solid(TDS)and total hardness(TH) are high,with the average values of 1244.03 mg/L and 492.10 mg/L,respectively.The types of groundwater are mainly HCO_3^--SO_4^(2-)-Ca^(2+)type in the runoff area and Cl^--SO_4^(2-)-Na^+type in the catchment area.Rock weathering and ion exchange are the main controlling factors of regional groundwater chemistry,followed by evaporative crystallization,and human activities have less impact on groundwater.The spatial difference of groundwater quality is obvious,the water quality of the catchment area is not suitable for drinking,and the suitability for plant growth is also poor.The groundwater in the runoff area can be used for drinking,but the hardness is slightly higher,which is more suitable for ecological purpose.
基金supported by the Scientific Research Foundation for High-Level Talents of Shihezi University(RCZK2018C41,CXRC201801,RCZK2018C22)the National Natural Science Foundation of China(41661040,U1803244)the Scientific and Technological Research Projects of Xinjiang Production and Construction Corps,China(2021AB021)。
文摘Changing climatic conditions and extensive human activities have influenced the global water cycle.In recent years,significant changes in climate and land use have degraded the watershed ecosystem of the Ebinur Lake Basin in Xinjiang,Northwest China.In this paper,variations of runoff,temperature,precipitation,reference evapotranspiration,lake area,socio-economic water usage,groundwater level and water quality in the Ebinur Lake Basin from 1961 to 2015 were systematically analyzed by the Mann-Kendall test methods(M-K)mutation test,the cumulative levelling method,the climate-sensitive method and land-use change index.In addition,we evaluated the effects of human activities on land use change and water quality.The results reveal that there was a significant increase in temperature and precipitation from 1961 to 2015,despite a decrease in reference evapotranspiration.The Wenquan station was not significantly affected by human activities as it is situated at a higher altitude.Runoff at this station increased significantly with climate warming.In contrast,runoff at the Jinghe station was severely affected by numerous human activities.Runoff decreased without obvious fluctuations.The contributions of climate change to runoff variation at the Jinghe and Wenquan stations were 46.87%and 58.94%,respectively;and the contributions of human activities were 53.13%and 41.06%,respectively.Land-use patterns in the basin have changed significantly between 1990 and 2015:urban and rural constructed lands,saline-alkali land,bare land,cultivated land,and forest land have expanded,while areas under grassland,lake,ice/snow and river/channel have declined.Human activities have dramatically intensified land degradation and desertification.From 1961 to 2015,both the inflow into the Ebinur Lake and the area of the lake have declined year by year;groundwater levels have dropped significantly,and the water quality has deteriorated during the study period.In the oasis irrigation area below the runoff pass,human activities mainly influenced the utilization mode and quantity of water resources.Changes in the hydrology and quantity of water resources were driven primarily by the continuous expansion of cultivated land and oasis,as well as the growth of population and the construction of hydraulic engineering projects.After 2015,the effects of some ecological protection projects were observed.However,there was no obvious sign of ecological improvement in the basin,and some environmental problems continue to persist.On this basis,this study recommends that the expansion of oasis should be limited according to the carrying capacity of the local water bodies.Moreover,in order to ensure the ecological security of the basin,it is necessary to determine the optimal oasis area for sustainable development and improve the efficiency of water resources exploitation and utilization.
基金supported by the National Natural Science Foundation of China (Grant Nos. 41902190 and 42003044)the Geological Survey Project of China (Grant No. DD20221913)the Qinghai Geological Exploration Fund (Grant No. 2020021068kc035)。
文摘The Quaternary was the main evaporite deposition period in the Qaidam Basin(QB), but the correlation between the evaporite deposition period and the glacial period is still unclear. In this study, the research objects are primarily evaporite-bearing strata in a 461.58 m-long drill core in the QB. X-ray powder diffraction(XRD) and scanning electron microscopy(SEM) were applied to study the evaporite minerals, U-Th dating being applied to construct the ~(230)Th geochronological framework. Evaporite deposition from Marine Isotope Stage(MIS) 15 to MIS 4 in the borehole was reconstructed via mineralogical and geochronological data. The evaporite minerals are mainly halite(NaCl), mirabilite(Na_(2)SO_(4)·10H_(2)O), thenardite(Na_(2)SO_(4)) and gypsum(CaSO_(4)·2H_(2)O). A total of 9 effective ~(230)Th data points, ranging from 492.5 ± 43.0 ka to 62.0 ± 11.9 ka, were obtained. The depositional age of the earliest halite layer in the borehole is 592.5–563.0 ka. There were mirabilite deposits in the QB during the cold glacial environment of MIS 6. During MIS 4, the study area desiccated, with mirabilite and halite being deposited. This study suggests that mirabilite is an indicator mineral for the glacial environment in the QB, while halite deposition does not correspond well to glaciation.
基金the National Science Foundation of China(Grants No.41502089,41302059 and 41202059)for their financial support
文摘Objective A total of 820 million tons of potash reserves are predicted to exist in the Palaeocene–Eocene of the Jianghan Basin.However,the basin history is still unclear concerning the potash enriching conditions and mechanism.The Well SKD1 is the first exploration well drilled in the Paleogene of Jianghan Basin with continuous coring,which was implemented in the
文摘The purpose of this paper is to present a brief concept of the ecological and environmental water demand of lake. The present situation and affecting factors of lake ecological system in the Haihe\|Luanhe Basin of North China was analyzed. The calculating method of the ecological and environmental water demand of the lake basis on the water body and the calculating method of the ecological and environmental water demand of the lake basis on the aquatic ecosystem, wetland and vegetation were compared and discussed. As the examples of Baiyangdian Lake and Beidagang Lake in Haihe\|Luanhe river basin, the ecological and environmental water demand of the two lakes was calculated to be 27×10\+8m\+3. It is 6.75 times to the water demand according to the calculating method of the ecological and environmental water demand of the lake basis on the water body. The research result indicated: (1) The calculating methods of the ecological and environmental water demand of the lake basis on the aquatic ecosystem should be better than only basis on the water body of lake. (2) The data, such as area of the vegetation kind around and in the lake, the vegetation coefficient, the evaporating amount of the vegetation and the vegetation water demand itself around and in the lake are lack and urgent need. Some suggestions for controlling and regulating the water resource of the lake in North China were proposed.
文摘The need for effective and efficient monitoring, evaluation and control of water quality in Lake Victoria Basin (LVB) has become more demanding in this era of urbanization, population growth and climate change and variability. Traditional methods that rely on collecting water samples, testing and analyses in water laboratories are not only costly but also lack capability for real-time data capture, analyses and fast dissemination of information to relevant stakeholders for making timely and informed decisions. In this paper, a Water Sensor Network (WSN) system prototype developed for water quality monitoring in LVB is presented. The development was preceded by evaluation of prevailing environment including availability of cellular network coverage at the site of operation. The system consists of an Arduino microcontroller, water quality sensors, and a wireless network connection module. It detects water temperature, dissolved oxygen, pH, and electrical conductivity in real-time and disseminates the information in graphical and tabular formats to relevant stakeholders through a web-based portal and mobile phone platforms. The experimental results show that the system has great prospect and can be used to operate in real world environment for optimum control and protection of water resources by providing key actors with relevant and timely information to facilitate quick action taking.
基金Under the auspices of Special Fund for Scientific Research in the Public Interestgranted by Ministry of Water Resources(No.2012010072,200701024)+3 种基金Key Program of National Natural Science Foundation of China(No.40730635)Open Foundation of State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering(No.2011491111)Research Foundation of Nanjing University of Information Science and Technology(No.20100406)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The typical regions of the Taihu Lake Basin,China,were selected to analyze the variation characteristics of river-lake networks under intensive human activities.The characteristics of the fractal dimension of river networks and lakes for different periods were investigated and the influences of river system evolution on water level changes were further explored through the comparison of their fractal characters.The results are as follows:1) River network development of the study area is becoming more monotonous and more simple;the number of lakes is reducing significantly,and the water surface ratio has dropped significantly since the 1980s.2) The box dimension of the river networks in all the cities of the study area decreased slowly from the 1960s to the 1980s,while the decrease was significant from the 1980s to the 2000s.The variations of lake correlation dimension are similar to those of the river network box dimensions.This is unfavorable for the storage capacity of the river networks and lakes.3) The Hurst exponents of water levels were all between 0.5 and 1.0 from the 1960s to the 1980s,while decreased in the 2000s,indicating the decline in persistence and increase in the complexity of water level series.The paper draws a conclusion that the relationship between the fractal dimension of river-lake networks and the Hurst exponents of the water level series can reveal the impacts of river system changes on flood disasters to some extent:the disappearance of river networks and lakes will increase the possibility of flood occurrence.
