Fine-grained sedimentary rocks often contain hydrocarbon and mineral resources.Compared with coarse-grained sedimentary rocks,fine-grained sedimentary rocks are less studied.To elucidate the lithofacies and pore struc...Fine-grained sedimentary rocks often contain hydrocarbon and mineral resources.Compared with coarse-grained sedimentary rocks,fine-grained sedimentary rocks are less studied.To elucidate the lithofacies and pore structure of lacustrine fine-grained rocks,the 340.6 m continuous core of Cretaceous Qing-1 Member from five wells in the southern central depression of the Songliao Basin was analyzed using X-ray diffraction,Rock-Eval pyrolysis,low-temperature nitrogen adsorption,high-pressure mercury injection,argon ion polishing-field emission scanning electron microscopy,and laser scanning confocal microscopy.Based on mineral compositions,organic matter abundance and sedimentary structure,lacustrine fine-grained rocks in the study area were divided into ten lithofacies,with their spatial distributions mainly influenced by tectonic cycle,climate cycle and provenance.Furthermore,pore structure characteristics of different lithofacies are summarized.(1)The siliceous mudstone lithofacies with low TOC content and the laminated/layered claybearing siliceous mudstone lithofacies with medium TOC content have the highest proportion of first-class pores(diameter>100 nm),making it the most favourable lithofacies for the accumulation of shale oil and shale gas.(2)The massive claybearing siliceous mudstone lithofacies with low TOC content has the highest proportion of second-class pores(diameter ranges from 10 to 100 nm),making it a favourable lithofacies for the enrichment of shale gas.(3)The massive clay-bearing siliceous mudstone lithofacies with high TOC content has the highest proportion of third-class pores(diameter<10 nm),making it intermediate in gas storage and flow.Laser confocal oil analysis shows that the heavy component of oil is mainly distributed in the clay lamina,while the light part with higher mobility is mainly concentrated in the silty lamina.展开更多
High-density resistivity imaging method is widely used in landslide monitoring.The resistivity of rock and soil is closely related to factors,such as porosity,moisture content,saturation and temperature.In this study,...High-density resistivity imaging method is widely used in landslide monitoring.The resistivity of rock and soil is closely related to factors,such as porosity,moisture content,saturation and temperature.In this study,the resistivity test was designed to investigate the influence of physical factors and pore solution components on the resistivity of landslide soil.Experimental and analytical results find that both moisture content and volumetric water content varies greatly under the same resistivity.At different temperatures,soil resistivity exhibits great changes.Under the same temperature,the ion concentration and species in pore solutions have great influence on soil resistivity.Based on the test results and grey correlation analysis,this study established a resistivity model by considering porosity,saturation,temperature and ion concentration.The study lays a foundation for the high-density resistivity method to measure the moisture content of landslides.展开更多
Microstructural features including pore size distribution, cell walls and phase compositions of magnesium oxychloride cement foams（MOCF） with various MgO powders and water mixture ratios were studied. Their infl uen...Microstructural features including pore size distribution, cell walls and phase compositions of magnesium oxychloride cement foams（MOCF） with various MgO powders and water mixture ratios were studied. Their infl uences on compressive strength, water absorption and resistance of MOCF were also discussed in detail. The experimental results indicated that moderate and slight excess MgO powders（MgO/MgCl2 molar ratios from 5.1 to 7） were beneficial to the formation of excellent microstructure of MOCF, but increasing water contents（H2O/MgO mass ratios from 0.9 to 1.29） might result in opposite conclusions. The microstructure of MOCF produced with moderate and slight excess MgO powders could enhance the compressive strength, while serious excess MgO powders addition（MgO/MgCl2 molar ratios = 9） would destroy the cell wall structures, and therefore decrease the strength of the system. Although MOCF produced with excess MgO powders could decrease the water absorption, its softening coefficient was lower than that of the material produced with moderate MgO powders. This might be due to the instability of phase 5, the volume expansion and cracking of cell walls as immersed the sample into water.展开更多
基金granted by the National Nature Science Foundation of China(Grants No.41902128 and 41872152)the Fundamental Research Funds for the Central Universities(Grant No.18CX02055A)+1 种基金the major national R&D projects(2017ZX05008-006-006002)the Key Laboratory for Strategic Evaluation of Shale Gas Resources,Ministry of Land and Resources(Grant No.20171101)。
文摘Fine-grained sedimentary rocks often contain hydrocarbon and mineral resources.Compared with coarse-grained sedimentary rocks,fine-grained sedimentary rocks are less studied.To elucidate the lithofacies and pore structure of lacustrine fine-grained rocks,the 340.6 m continuous core of Cretaceous Qing-1 Member from five wells in the southern central depression of the Songliao Basin was analyzed using X-ray diffraction,Rock-Eval pyrolysis,low-temperature nitrogen adsorption,high-pressure mercury injection,argon ion polishing-field emission scanning electron microscopy,and laser scanning confocal microscopy.Based on mineral compositions,organic matter abundance and sedimentary structure,lacustrine fine-grained rocks in the study area were divided into ten lithofacies,with their spatial distributions mainly influenced by tectonic cycle,climate cycle and provenance.Furthermore,pore structure characteristics of different lithofacies are summarized.(1)The siliceous mudstone lithofacies with low TOC content and the laminated/layered claybearing siliceous mudstone lithofacies with medium TOC content have the highest proportion of first-class pores(diameter>100 nm),making it the most favourable lithofacies for the accumulation of shale oil and shale gas.(2)The massive claybearing siliceous mudstone lithofacies with low TOC content has the highest proportion of second-class pores(diameter ranges from 10 to 100 nm),making it a favourable lithofacies for the enrichment of shale gas.(3)The massive clay-bearing siliceous mudstone lithofacies with high TOC content has the highest proportion of third-class pores(diameter<10 nm),making it intermediate in gas storage and flow.Laser confocal oil analysis shows that the heavy component of oil is mainly distributed in the clay lamina,while the light part with higher mobility is mainly concentrated in the silty lamina.
基金supported by Hubei Provincial Engineering Research Center of Slope Habitat Construction Technique Using Cement-based Materials(China Three Gorges University)No.2022SNJ15。
文摘High-density resistivity imaging method is widely used in landslide monitoring.The resistivity of rock and soil is closely related to factors,such as porosity,moisture content,saturation and temperature.In this study,the resistivity test was designed to investigate the influence of physical factors and pore solution components on the resistivity of landslide soil.Experimental and analytical results find that both moisture content and volumetric water content varies greatly under the same resistivity.At different temperatures,soil resistivity exhibits great changes.Under the same temperature,the ion concentration and species in pore solutions have great influence on soil resistivity.Based on the test results and grey correlation analysis,this study established a resistivity model by considering porosity,saturation,temperature and ion concentration.The study lays a foundation for the high-density resistivity method to measure the moisture content of landslides.
基金Funded by the National Natural Science Foundation of China(No.51478370)the EPSRC-NSFC Joint Research Projec(No.51461135005)
文摘Microstructural features including pore size distribution, cell walls and phase compositions of magnesium oxychloride cement foams（MOCF） with various MgO powders and water mixture ratios were studied. Their infl uences on compressive strength, water absorption and resistance of MOCF were also discussed in detail. The experimental results indicated that moderate and slight excess MgO powders（MgO/MgCl2 molar ratios from 5.1 to 7） were beneficial to the formation of excellent microstructure of MOCF, but increasing water contents（H2O/MgO mass ratios from 0.9 to 1.29） might result in opposite conclusions. The microstructure of MOCF produced with moderate and slight excess MgO powders could enhance the compressive strength, while serious excess MgO powders addition（MgO/MgCl2 molar ratios = 9） would destroy the cell wall structures, and therefore decrease the strength of the system. Although MOCF produced with excess MgO powders could decrease the water absorption, its softening coefficient was lower than that of the material produced with moderate MgO powders. This might be due to the instability of phase 5, the volume expansion and cracking of cell walls as immersed the sample into water.
