In this study,90 surface water samples were collected from Shandong Province(SDP)in the dry and wet seasons and analyzed using statistical analysis,hydrochemical methods and water quality index(WQI).The content of mai...In this study,90 surface water samples were collected from Shandong Province(SDP)in the dry and wet seasons and analyzed using statistical analysis,hydrochemical methods and water quality index(WQI).The content of main ions showed seasonal variations,with a higher average value in the dry season than in the wet season.Sampling points exhibiting high contents of the main chemical components were mainly distributed in areas southwest of SDP,north of Weifang,and around Jinan.The saturation index of carbonate minerals was greater than zero,while that of evaporite minerals was less than zero.The hydrochemical characteristics of surface water are mainly dominated by rock weathering as well as cation exchange.In addition,surface water in SDP has significantly been affected by anthropogenic factors.Most of the surface water could be classified as weakly alkaline soft-fresh water,with the hydrochemical types of SO_(4)·Cl-Ca·Mg and SO_(4)·Cl-Na.In terms of WQI,47.88% and 37.88% of the water samples in SDP were classified as poor water in the dry and wet seasons,respectively.On the whole,the water quality is higher in the wet season than in the dry season,and surface water in SDP is generally suitable for agricultural irrigation.展开更多
Due to the complex conditions and strong heterogeneity of tight sandstone reservoirs,the reservoirs should be classified and the controlling factors of physical properties should be studied.Cast thin section observati...Due to the complex conditions and strong heterogeneity of tight sandstone reservoirs,the reservoirs should be classified and the controlling factors of physical properties should be studied.Cast thin section observations,cathodoluminescence,scanning electron microscopy(SEM),X-ray diffraction(XRD),and high-pressure mercury injection(HPMI)were used to classify and optimize the reservoir.The Brooks-Corey model and stepwise regression were used to study the fractal dimension and main controlling factors of the physical properties of the high-quality reservoir.The results show that the reservoirs in the study area can be divided into four types,and the high-quality reservoir has the best physical properties and pore-throat characteristics.In the high-quality reservoir,the homogeneity of transitional pores was the best,followed by that of micropores,and the worst was mesopores.The porosity was controlled by depth and kaolinite.The model with standardized coefficients is y=12.454−0.778×(Depth)+0.395×(Kaolinite).The permeability was controlled by depth,illite/montmorillonite,and siliceous cement,and the model with standardized coefficients is y=1.689−0.683×(Depth)−0.395×(Illite/Montmorillonite)−0.337×(Siliceous Cement).The pore-throat evolutionary model shows that the early-middle diagenetic period was when the reservoir physical properties were at their best,and the kaolinite intercrystalline pores and residual intergranular pores were the most important.展开更多
基金financially supported by National Natural Science Foundation of China(Nos.41772257,41472216)the Research Project of Shandong Province Bureau of Geology and Mineral Resources(Nos.KY2018003,KY201933)the Shandong Provincial Geological Environment Exploration Project(2016)No.3。
文摘In this study,90 surface water samples were collected from Shandong Province(SDP)in the dry and wet seasons and analyzed using statistical analysis,hydrochemical methods and water quality index(WQI).The content of main ions showed seasonal variations,with a higher average value in the dry season than in the wet season.Sampling points exhibiting high contents of the main chemical components were mainly distributed in areas southwest of SDP,north of Weifang,and around Jinan.The saturation index of carbonate minerals was greater than zero,while that of evaporite minerals was less than zero.The hydrochemical characteristics of surface water are mainly dominated by rock weathering as well as cation exchange.In addition,surface water in SDP has significantly been affected by anthropogenic factors.Most of the surface water could be classified as weakly alkaline soft-fresh water,with the hydrochemical types of SO_(4)·Cl-Ca·Mg and SO_(4)·Cl-Na.In terms of WQI,47.88% and 37.88% of the water samples in SDP were classified as poor water in the dry and wet seasons,respectively.On the whole,the water quality is higher in the wet season than in the dry season,and surface water in SDP is generally suitable for agricultural irrigation.
基金financially supported by the National Natural Science Foundation of China(Nos.41972172 and U1910205).
文摘Due to the complex conditions and strong heterogeneity of tight sandstone reservoirs,the reservoirs should be classified and the controlling factors of physical properties should be studied.Cast thin section observations,cathodoluminescence,scanning electron microscopy(SEM),X-ray diffraction(XRD),and high-pressure mercury injection(HPMI)were used to classify and optimize the reservoir.The Brooks-Corey model and stepwise regression were used to study the fractal dimension and main controlling factors of the physical properties of the high-quality reservoir.The results show that the reservoirs in the study area can be divided into four types,and the high-quality reservoir has the best physical properties and pore-throat characteristics.In the high-quality reservoir,the homogeneity of transitional pores was the best,followed by that of micropores,and the worst was mesopores.The porosity was controlled by depth and kaolinite.The model with standardized coefficients is y=12.454−0.778×(Depth)+0.395×(Kaolinite).The permeability was controlled by depth,illite/montmorillonite,and siliceous cement,and the model with standardized coefficients is y=1.689−0.683×(Depth)−0.395×(Illite/Montmorillonite)−0.337×(Siliceous Cement).The pore-throat evolutionary model shows that the early-middle diagenetic period was when the reservoir physical properties were at their best,and the kaolinite intercrystalline pores and residual intergranular pores were the most important.
