The marine-continental transitional shale of the Upper Permian Longtan Formation is widely distributed in Hunan and shows significant exploration potential.Frequent changes in lithofacies have however notably influenc...The marine-continental transitional shale of the Upper Permian Longtan Formation is widely distributed in Hunan and shows significant exploration potential.Frequent changes in lithofacies have however notably influenced the shale gas enrichment.The strata of the Longtan Formation in the Shaoyang Depression,central Hunan,were taken as the study object for this project.Three lithofacies assemblages were identified:shale interbedded with sandstone layer(SAL),sandstone interbedded with shale layer(ASL)and laminated shale layer(LSL).The SAL shale shows significant variability in hydrocarbon generation potential,which leads to shale gas characterized by'hydrocarbon generation in high total organic carbon(TOC)shale,retention in low TOC shale and accumulation in sandstone'.The ASL shale,influenced by the redox conditions of the depositional environment,shows a lower concentration of organic matter.This results in an enrichment model of'hydrocarbon generation and accumulation in shale,with sealing by sandstone'.The laminar structure of LSL shale causes both quartz and clay minerals to control the reservoir.Shale gas is characterized by'hydrocarbon generation in mud laminae,retention and accumulation in silty laminae,with multiple intra-source migration paths'.In the marine-continental transitional shale gas system,the enrichment intervals of different types of shale gas reservoirs exhibit significant variability.展开更多
The characteristic and status quo of plant biodiversity in Longtan Nature Reserve was evaluated from the three aspects of species diversity, genetic diversity and ecosystem dioversity. And the primary eco-safety influ...The characteristic and status quo of plant biodiversity in Longtan Nature Reserve was evaluated from the three aspects of species diversity, genetic diversity and ecosystem dioversity. And the primary eco-safety influencing factors for plant biodiversity in Longtan nature reserve were put forward. The results show that the plant species in Longtan Nature Reserve was abundant, including 2 821 species of vascular bundle plants belonging to 1029 genera, 205 families. The main problems influencing eco-safety included the destruction of endangered wild plants and exotic species invasion.展开更多
To further explore characteristics of tourist resources in Liuchong and Longtan Scenic spots in Longtan National Forest Park,Classification,Investigation and Evaluation of Tourist Resources(GB/T18972-2003) and Quality...To further explore characteristics of tourist resources in Liuchong and Longtan Scenic spots in Longtan National Forest Park,Classification,Investigation and Evaluation of Tourist Resources(GB/T18972-2003) and Quality Grading of Scenic Resources in Forest Parks of China(GB/T18005-1999) were adopted to analyze composition and distribution features of tourist resources in Liuchong and Longtan Scenic Spots,qualitative evaluation of scenic resources in the 2 study scenic spots,quantitative evaluation of resource units and quality evaluation of tourist resources were respectively carried out.The results showed that the park has diversified tourist resources such as peaks,valleys,cliffs,brooks,waterfalls and forests,as well as rich animal and plant species and an excellent natural eco-environment;5 Grade-IV tourist landscapes,6 Grade-III tourist landscapes,14 Grade-II ones,4 Grade-I ones;quality of tourist resources was scored as 41.3,up to the scenic resource standards of Grade-I Forest Park.展开更多
Coal measure gas(also known as coal-bearing unconventional gas)is the key field and development direction of unconventional natural gas in recent years.The exploration and evaluation of coal measure gas(coalbed methan...Coal measure gas(also known as coal-bearing unconventional gas)is the key field and development direction of unconventional natural gas in recent years.The exploration and evaluation of coal measure gas(coalbed methane,coal shale gas and coal measure tight sandstone gas)from single coalbed methane has greatly expanded the field and space of resource evaluation,which is of positive significance for realizing the comprehensive utilization of coal resources,maximizing the benefits and promoting the innovation of oil and gas geological theory and technological advances in exploration and development.For the first time,in Yangmeishu Syncline of Western Guizhou Province,the public welfare coalbed methane geological survey project of China Geological Survey has been carried out a systematic geological survey of coal measure gas for the Upper Permian Longtan Formation,identified the geological conditions of coal measure gas and found high quality resources.The total geological resource quantity of coalbed methane and coal shale gas is 51.423×109 m3 and the geological resource abundance is up to 566×106 m3/km2.In this area,the coal measures are characterized by many layers of minable coal seams,large total thickness,thin to the medium thickness of the single layer,good gas-bearing property of coal seams and coal measure mudstone and sandstone,good reservoir physical property and high-pressure coefficient.According to the principle of combination of high quality and similarity of key parameters of the coal reservoir,the most favorable intervals are No.5-2,No.7 and No.13-2 coal seam in Well YMC1.And the pilot tests are carried out on coal seams and roof silty mudstone,such as staged perforation,increasing hydraulic fracturing scale and"three gas"production.The high and stable industrial gas flow with a daily gas output of more than 4000 m3 has been obtained,which has realized the breakthrough in the geological survey of coal measure gas in Southwest China.Based on the above investigation results,the geological characteristics of coal measure gas in the multi-thin-coal-seam-developed area and the coexploration and co-production methods,such as the optimization method of favorable intervals,the highefficiency fracturing and reservoir reconstruction method of coal measures,and the"three gas"drainage and production system,are systematically summarized in this paper.It will provide a reference for efficient exploration and development of coal measure gas in similar geological conditions in China.展开更多
In this work,the Permian Longtan marine-continental transitional shale in the southeast of Sichuan Basin was taken as study object.Through petrology and geochemical analysis,lithofacies types of the marine-continental...In this work,the Permian Longtan marine-continental transitional shale in the southeast of Sichuan Basin was taken as study object.Through petrology and geochemical analysis,lithofacies types of the marine-continental transitional shale were classified,key controlling factors of physical properties and gas content of the different shale lithofacies were analyzed.The research results show that the Longtan Formation marine-continental transitional shale in the study area has four types of lithofacies,namely,organic-lean calcareous shale,organic-lean mixed shale,organic-lean argillaceous shale,and organic-rich argillaceous shale,among which the organic-rich argillaceous shale is the most favorable lithofacies of the study area.The pore types of different lithofacies vary significantly and the clay mineral-related pore is the dominant type of the pore system in the study area.The main controlling factor of the physical properties is clay mineral content,and the most important factor affecting gas content is TOC content.Compared with marine shale,the marine-continental transitional shale has low average values,wide distribution range,and strong heterogeneity in TOC content,porosity,and pore structure parameters,but still contains some favorable layers with high physical properties and gas contents.The organic-rich clay shale deposited in tidal flat-lagoon system is most likely to form shale gas sweet spots,so it should be paid more attention in shale gas exploration.展开更多
The marine–continental transitional shale (MCTS) reservoirs of the Longtan Formation (LTF) are widely distributed in the Sichuan Basin. However, the LTF shale exhibits considerable variations in mineral composition a...The marine–continental transitional shale (MCTS) reservoirs of the Longtan Formation (LTF) are widely distributed in the Sichuan Basin. However, the LTF shale exhibits considerable variations in mineral composition and pore characteristics, which makes identifying the 'sweet spot'a challenging task. To address this issue, 10 samples from four typical shale gas wells in the LTF in the southern Sichuan Basin were selected and analyzed for total organic carbon (TOC) content, whole-rock composition using X-ray diffraction (XRD), low-pressure gas adsorption, and high-pressure mercury intrusion. The lithofacies distribution and pore structure of the MCTS were studied to determine the pore structural characteristics and the primary factors influencing pore formation in different types of shale lithofacies in the LTF. The lithofacies of the LTF shale in the study area can be classified into three categories: siliceous clay shale, clay shale and mixed shale. Mineral content has a significant impact on the pore characteristics, while TOC content has a minor effect on the pore volume and specific surface area of micropores and mesopores. It can be inferred that the mesopores in the MCTS are mainly related to clay mineral pores, and mineral dissolution and TOC content are not the primary factors contributing to pore formation.展开更多
The northern type Longtan Formation of the Late Permian in central Hunan is dominated by an assemblage of greyish black mudstone,siltstone, sandy mudstone,fine sandstone and coals,and contains a variety of sedimentary...The northern type Longtan Formation of the Late Permian in central Hunan is dominated by an assemblage of greyish black mudstone,siltstone, sandy mudstone,fine sandstone and coals,and contains a variety of sedimentary structures such as thin sandstone-mudstone interbedded bedding,flaser beddings,lenticular beddings,horizontal展开更多
Longtan pearl plum, as a new dominant fruit industry in Guangxi, has developed rapidly in recent years and become one of the major economic sources of fruit growers in Guangxi. It has a positive effect on promoting ec...Longtan pearl plum, as a new dominant fruit industry in Guangxi, has developed rapidly in recent years and become one of the major economic sources of fruit growers in Guangxi. It has a positive effect on promoting economic development and helping farmers to get out of poverty in Guangxi. But there is almost nothing to do with the processing and utilization. Taking the route of processing and utilization is an inevitable trend of development of Longtan pearl plum industry with the increase of the planting area and yield year by year. In this paper, based on the analysis of edible value of Longtan pearl plum, the development direction of processing and utilization of Longtan pearl plum was expounded, and some suggestions on the problems existing in the processing and utilization were put forward to provide reference for the processing and utilization of Longtan pearl plum.展开更多
[Objectives]This study was conducted to investigate the correlation between leaf blight of pearl plum and nutrient elements from the perspective of plant nutrition.[Methods]Branch and leaf samples of pearl plum plants...[Objectives]This study was conducted to investigate the correlation between leaf blight of pearl plum and nutrient elements from the perspective of plant nutrition.[Methods]Branch and leaf samples of pearl plum plants infected by or free of leaf blight and the corresponding 0-30 cm cultivated soil were collected,and statistical analysis was conducted according to the changes in nutrient contents and the incidence of leaf blight,so as to look for nutrients in pearl plum plants associated with leaf blight,as well as soil constraint factors.[Results]Phosphorus,iron and manganese in nutrients may be related to leaf blight,and the factors affecting leaf blight may be the ratios of P/Fe and P/Mn in leaves.[Conclusions]This study provides a basis for further research on the relationship between phosphorus,iron and manganese on the effect of leaf blight in pearl plum trees.展开更多
Long Tan Hydroelectric Station is planned to be built in the middle reaches of Hong Shui River between the Guongxi Zhuang Autonomous Region and Guizhou Province where the terrain is complicated and the traffic is unco...Long Tan Hydroelectric Station is planned to be built in the middle reaches of Hong Shui River between the Guongxi Zhuang Autonomous Region and Guizhou Province where the terrain is complicated and the traffic is unconvenient. In order to speed up engineering design, the synthetical remote sensing survey and mapping had been made展开更多
A large number of the Carlin-type gold deposits occur in the Longtan Formation in southwestern Guizhou Province.The Long-tan Formation contains abundant basalt,tuff and siliceous rocks.All rocks of the Longtan Formati...A large number of the Carlin-type gold deposits occur in the Longtan Formation in southwestern Guizhou Province.The Long-tan Formation contains abundant basalt,tuff and siliceous rocks.All rocks of the Longtan Formation are enriched in gold,which were deposited in a limited platform environment in the transition zone from marine to continental.The process of sedimentation was accompanied by the eruption of Emeishan basalt and hydrothermal deposition controlled by co-sedimentary submarine deep faults in the west,which led to the formation of a peculiar gold-bearing formation with coal series strata.This formation controlled the occurrence of the Carlin-type gold deposits in southwestern Guizhou Province.In response to the remobilization of the Emei mantle plume during the Yanshanian period,As,Au and other ore-forming materials were continuously extracted by deeply circulating waters from the Emeishan basalt and coal seams,thereafter forming ore-forming hydrothermal solutions.When these elements were transported in the coal seams,large amounts of As,Au and other elements were enriched in pyrite within the coal seams,thus forming high-As coal and Carlin-type gold deposits in the Longtan Formation coal series strata.展开更多
The air entrainment for avoiding cavitation damage has been widely used in long free flow tunnels. It is crucial to determine whether an aerator is needed for shorter tunnels. In this article, the bottom discharge tun...The air entrainment for avoiding cavitation damage has been widely used in long free flow tunnels. It is crucial to determine whether an aerator is needed for shorter tunnels. In this article, the bottom discharge tunnel at the Longtan Hydropower Station was involved, for which the free flow tunnel section was only 50.00 m long. The cavitation in the tunnel with and without the aerator was investigated using the physical models of the scale 1/30, through the measurements of cavitation noise. The experimental results show that it is necessary to place the aerator at the inlet of the free flow section for higher reservoir level to protect this tunnel from cavitation damage.展开更多
基金financial support from the National Natural Science Foundation of China(Grant Nos.U23B20155 and 42202140)the Science and Technology Innovation Program of Hunan Province(2023RC1021)+1 种基金the China Geological Survey(DD20221659)the Science and Technology Bureau,Changsha,China(kq2208261)。
文摘The marine-continental transitional shale of the Upper Permian Longtan Formation is widely distributed in Hunan and shows significant exploration potential.Frequent changes in lithofacies have however notably influenced the shale gas enrichment.The strata of the Longtan Formation in the Shaoyang Depression,central Hunan,were taken as the study object for this project.Three lithofacies assemblages were identified:shale interbedded with sandstone layer(SAL),sandstone interbedded with shale layer(ASL)and laminated shale layer(LSL).The SAL shale shows significant variability in hydrocarbon generation potential,which leads to shale gas characterized by'hydrocarbon generation in high total organic carbon(TOC)shale,retention in low TOC shale and accumulation in sandstone'.The ASL shale,influenced by the redox conditions of the depositional environment,shows a lower concentration of organic matter.This results in an enrichment model of'hydrocarbon generation and accumulation in shale,with sealing by sandstone'.The laminar structure of LSL shale causes both quartz and clay minerals to control the reservoir.Shale gas is characterized by'hydrocarbon generation in mud laminae,retention and accumulation in silty laminae,with multiple intra-source migration paths'.In the marine-continental transitional shale gas system,the enrichment intervals of different types of shale gas reservoirs exhibit significant variability.
基金Supported by Scientific Research Program of Guangxi Provincial Department of Education(201103YB128,201010LX500)Key scientific research project of Baise University(2012KA02)+1 种基金Integrated Construction Program of Characteristic Biotechnology Majors and Courses(GXTSZY224)2011 Young Teachers Growth Foundation of Baise University~~
文摘The characteristic and status quo of plant biodiversity in Longtan Nature Reserve was evaluated from the three aspects of species diversity, genetic diversity and ecosystem dioversity. And the primary eco-safety influencing factors for plant biodiversity in Longtan nature reserve were put forward. The results show that the plant species in Longtan Nature Reserve was abundant, including 2 821 species of vascular bundle plants belonging to 1029 genera, 205 families. The main problems influencing eco-safety included the destruction of endangered wild plants and exotic species invasion.
文摘To further explore characteristics of tourist resources in Liuchong and Longtan Scenic spots in Longtan National Forest Park,Classification,Investigation and Evaluation of Tourist Resources(GB/T18972-2003) and Quality Grading of Scenic Resources in Forest Parks of China(GB/T18005-1999) were adopted to analyze composition and distribution features of tourist resources in Liuchong and Longtan Scenic Spots,qualitative evaluation of scenic resources in the 2 study scenic spots,quantitative evaluation of resource units and quality evaluation of tourist resources were respectively carried out.The results showed that the park has diversified tourist resources such as peaks,valleys,cliffs,brooks,waterfalls and forests,as well as rich animal and plant species and an excellent natural eco-environment;5 Grade-IV tourist landscapes,6 Grade-III tourist landscapes,14 Grade-II ones,4 Grade-I ones;quality of tourist resources was scored as 41.3,up to the scenic resource standards of Grade-I Forest Park.
基金This study was supported by the China Geological Survey Projects(DD20160186,12120115008201)
文摘Coal measure gas(also known as coal-bearing unconventional gas)is the key field and development direction of unconventional natural gas in recent years.The exploration and evaluation of coal measure gas(coalbed methane,coal shale gas and coal measure tight sandstone gas)from single coalbed methane has greatly expanded the field and space of resource evaluation,which is of positive significance for realizing the comprehensive utilization of coal resources,maximizing the benefits and promoting the innovation of oil and gas geological theory and technological advances in exploration and development.For the first time,in Yangmeishu Syncline of Western Guizhou Province,the public welfare coalbed methane geological survey project of China Geological Survey has been carried out a systematic geological survey of coal measure gas for the Upper Permian Longtan Formation,identified the geological conditions of coal measure gas and found high quality resources.The total geological resource quantity of coalbed methane and coal shale gas is 51.423×109 m3 and the geological resource abundance is up to 566×106 m3/km2.In this area,the coal measures are characterized by many layers of minable coal seams,large total thickness,thin to the medium thickness of the single layer,good gas-bearing property of coal seams and coal measure mudstone and sandstone,good reservoir physical property and high-pressure coefficient.According to the principle of combination of high quality and similarity of key parameters of the coal reservoir,the most favorable intervals are No.5-2,No.7 and No.13-2 coal seam in Well YMC1.And the pilot tests are carried out on coal seams and roof silty mudstone,such as staged perforation,increasing hydraulic fracturing scale and"three gas"production.The high and stable industrial gas flow with a daily gas output of more than 4000 m3 has been obtained,which has realized the breakthrough in the geological survey of coal measure gas in Southwest China.Based on the above investigation results,the geological characteristics of coal measure gas in the multi-thin-coal-seam-developed area and the coexploration and co-production methods,such as the optimization method of favorable intervals,the highefficiency fracturing and reservoir reconstruction method of coal measures,and the"three gas"drainage and production system,are systematically summarized in this paper.It will provide a reference for efficient exploration and development of coal measure gas in similar geological conditions in China.
基金Supported by the National Natural Science Foundation (U19B6003).
文摘In this work,the Permian Longtan marine-continental transitional shale in the southeast of Sichuan Basin was taken as study object.Through petrology and geochemical analysis,lithofacies types of the marine-continental transitional shale were classified,key controlling factors of physical properties and gas content of the different shale lithofacies were analyzed.The research results show that the Longtan Formation marine-continental transitional shale in the study area has four types of lithofacies,namely,organic-lean calcareous shale,organic-lean mixed shale,organic-lean argillaceous shale,and organic-rich argillaceous shale,among which the organic-rich argillaceous shale is the most favorable lithofacies of the study area.The pore types of different lithofacies vary significantly and the clay mineral-related pore is the dominant type of the pore system in the study area.The main controlling factor of the physical properties is clay mineral content,and the most important factor affecting gas content is TOC content.Compared with marine shale,the marine-continental transitional shale has low average values,wide distribution range,and strong heterogeneity in TOC content,porosity,and pore structure parameters,but still contains some favorable layers with high physical properties and gas contents.The organic-rich clay shale deposited in tidal flat-lagoon system is most likely to form shale gas sweet spots,so it should be paid more attention in shale gas exploration.
基金supported by the National Natural Science Foundation of China(NNSFC)(Grant No.42272184)2022 Research Program of PetroChina Southwest Oil and Gas Field Company(2022JS-1809).
文摘The marine–continental transitional shale (MCTS) reservoirs of the Longtan Formation (LTF) are widely distributed in the Sichuan Basin. However, the LTF shale exhibits considerable variations in mineral composition and pore characteristics, which makes identifying the 'sweet spot'a challenging task. To address this issue, 10 samples from four typical shale gas wells in the LTF in the southern Sichuan Basin were selected and analyzed for total organic carbon (TOC) content, whole-rock composition using X-ray diffraction (XRD), low-pressure gas adsorption, and high-pressure mercury intrusion. The lithofacies distribution and pore structure of the MCTS were studied to determine the pore structural characteristics and the primary factors influencing pore formation in different types of shale lithofacies in the LTF. The lithofacies of the LTF shale in the study area can be classified into three categories: siliceous clay shale, clay shale and mixed shale. Mineral content has a significant impact on the pore characteristics, while TOC content has a minor effect on the pore volume and specific surface area of micropores and mesopores. It can be inferred that the mesopores in the MCTS are mainly related to clay mineral pores, and mineral dissolution and TOC content are not the primary factors contributing to pore formation.
文摘The northern type Longtan Formation of the Late Permian in central Hunan is dominated by an assemblage of greyish black mudstone,siltstone, sandy mudstone,fine sandstone and coals,and contains a variety of sedimentary structures such as thin sandstone-mudstone interbedded bedding,flaser beddings,lenticular beddings,horizontal
基金Supported by Special Project for Guangxi Science and Technology Bases and Talent(GK AD16380088,GK AD17195040)Key Research and Development Plan of Guangxi(GK AB18221070)+1 种基金Major Science and Technology Project of Guangxi(GK AA17202029,G AA17204058-19,G AA17204058-20)Project of Guangxi Academy of Agricultural Sciences(2015YT87,2018YT29,2018YM05)
文摘Longtan pearl plum, as a new dominant fruit industry in Guangxi, has developed rapidly in recent years and become one of the major economic sources of fruit growers in Guangxi. It has a positive effect on promoting economic development and helping farmers to get out of poverty in Guangxi. But there is almost nothing to do with the processing and utilization. Taking the route of processing and utilization is an inevitable trend of development of Longtan pearl plum industry with the increase of the planting area and yield year by year. In this paper, based on the analysis of edible value of Longtan pearl plum, the development direction of processing and utilization of Longtan pearl plum was expounded, and some suggestions on the problems existing in the processing and utilization were put forward to provide reference for the processing and utilization of Longtan pearl plum.
基金Supported by Guangxi Key Research and Development Project(GK AB18294010)Special Project of Basic Scientific Research Business of Guangxi Academy of Agricultural Sciences(GNK 2021YT036)Key Project of Science and Technology Development Fund of Guangxi Academy of Agricultural Sciences(GNK 2016JZ09)。
文摘[Objectives]This study was conducted to investigate the correlation between leaf blight of pearl plum and nutrient elements from the perspective of plant nutrition.[Methods]Branch and leaf samples of pearl plum plants infected by or free of leaf blight and the corresponding 0-30 cm cultivated soil were collected,and statistical analysis was conducted according to the changes in nutrient contents and the incidence of leaf blight,so as to look for nutrients in pearl plum plants associated with leaf blight,as well as soil constraint factors.[Results]Phosphorus,iron and manganese in nutrients may be related to leaf blight,and the factors affecting leaf blight may be the ratios of P/Fe and P/Mn in leaves.[Conclusions]This study provides a basis for further research on the relationship between phosphorus,iron and manganese on the effect of leaf blight in pearl plum trees.
文摘Long Tan Hydroelectric Station is planned to be built in the middle reaches of Hong Shui River between the Guongxi Zhuang Autonomous Region and Guizhou Province where the terrain is complicated and the traffic is unconvenient. In order to speed up engineering design, the synthetical remote sensing survey and mapping had been made
文摘A large number of the Carlin-type gold deposits occur in the Longtan Formation in southwestern Guizhou Province.The Long-tan Formation contains abundant basalt,tuff and siliceous rocks.All rocks of the Longtan Formation are enriched in gold,which were deposited in a limited platform environment in the transition zone from marine to continental.The process of sedimentation was accompanied by the eruption of Emeishan basalt and hydrothermal deposition controlled by co-sedimentary submarine deep faults in the west,which led to the formation of a peculiar gold-bearing formation with coal series strata.This formation controlled the occurrence of the Carlin-type gold deposits in southwestern Guizhou Province.In response to the remobilization of the Emei mantle plume during the Yanshanian period,As,Au and other ore-forming materials were continuously extracted by deeply circulating waters from the Emeishan basalt and coal seams,thereafter forming ore-forming hydrothermal solutions.When these elements were transported in the coal seams,large amounts of As,Au and other elements were enriched in pyrite within the coal seams,thus forming high-As coal and Carlin-type gold deposits in the Longtan Formation coal series strata.
基金Project supported by the National Natural Science Foundation of China (Grant No: 50539060) and the Innovative Project of Graduate Student in Jiangsu Province (Grant No: 2005-60)
文摘The air entrainment for avoiding cavitation damage has been widely used in long free flow tunnels. It is crucial to determine whether an aerator is needed for shorter tunnels. In this article, the bottom discharge tunnel at the Longtan Hydropower Station was involved, for which the free flow tunnel section was only 50.00 m long. The cavitation in the tunnel with and without the aerator was investigated using the physical models of the scale 1/30, through the measurements of cavitation noise. The experimental results show that it is necessary to place the aerator at the inlet of the free flow section for higher reservoir level to protect this tunnel from cavitation damage.
