Marine strata in the Jianghan Plain area are widely distributed with a total depth of more than 8,000 m from the Upper Sinian to the Middle Triassic. Six reservoir caprock units, named Z-C2, C2-O, S, D--C, P and T1, c...Marine strata in the Jianghan Plain area are widely distributed with a total depth of more than 8,000 m from the Upper Sinian to the Middle Triassic. Six reservoir caprock units, named Z-C2, C2-O, S, D--C, P and T1, can be identified with each epoch. The geology, stratigraphy, drilling, oil testing and other basic data as well as the measured inclusion and strontium isotope data in the study area are used in the analysis of the formation and evolution process of marine petroliferous reservoirs in the Jianghan Plain area. This study aims to provide a scientific basis for the further exploration of hydrocarbons in the Jianghan Plain and reduce the risks by analyzing the key factors for hydrocarbon accumulation in the marine strata. Our findings show that in the Lower Palaeozoic hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the early period of the Early Yanshanian, and the hydrocarbon reservoir was destroyed in the middle-late period of the Early Yanshanian. In the Lower Triassic-Carboniferous hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the Early Yanshanian, and the hydrocarbon reservoir suffered destruction from the Late Yanshanian to the Early Himalayanian. The preservation conditions of the marine strata in the Jianghan Plain area have been improved since the Late Himalayanian. However, because all source beds have missed the oil/gas generation fastigium and lost the capacity to generate secondary hydrocarbon, no reaccumulation of hydrocarbons can be detected in the study area＇s marine strata. No industrially exploitable oil/gas reservoir has been discovered in the marine strata of Jianghan Plain area since exploration began in 1958. This study confirms that petroliferous reservoirs in the marine strata have been completely destroyed, and that poor preservation conditions are the primary factor leading to unsuccessful hydrocarbon exploration. It is safely concluded that hydrocarbon exploration in the marine strata of the study area is quite risky.展开更多
The relationship between species diversity and ecosystem function is a hot topic in ecology and environics.This paper investi-gates the evolution of diversity of the late Middle Permian brachiopods community in Hechua...The relationship between species diversity and ecosystem function is a hot topic in ecology and environics.This paper investi-gates the evolution of diversity of the late Middle Permian brachiopods community in Hechuan,Chongqing,China,and dis-cusses the relationship between species diversity and community productivity in terms of the geohistorical development.This paper shows that the species diversity is externalized by several indexes,and the relationship between diversity and productiv-ity is too complex to be described by a single assumption.The relationship between species diversity and community produc-tivity is restricted by environment and community evolution.When the community succeeds normally,the relationship be-tween species richness index,species diversity index,and species evenness index to productivity is in linear dependence rela-tion to each other,which is met with the third assumption.But,when the environment interference surpasses the bearing capa-bility of the community,not only the community succession will be terminated and be replaced by another one,but also the relationship between species richness index,species diversity index,and species evenness index to productivity is also in-versed to negative correlation by the interference from environment.Only the relationship between ecological dominance and productivity is in linear dependence relation to each other and approximately met with the third assumption.It is illustrated that the assumption that the productivity is in linear dependence relation with diversity should be established on the presupposition that the community succession is normal.展开更多
基金the subsidization of a Major Project of Chinese National Programs for Fundamental Research and Development (973 Program, No. 2012CB214805)supported by the Chinese National Natural Science Foundation (No. 41372141)
文摘Marine strata in the Jianghan Plain area are widely distributed with a total depth of more than 8,000 m from the Upper Sinian to the Middle Triassic. Six reservoir caprock units, named Z-C2, C2-O, S, D--C, P and T1, can be identified with each epoch. The geology, stratigraphy, drilling, oil testing and other basic data as well as the measured inclusion and strontium isotope data in the study area are used in the analysis of the formation and evolution process of marine petroliferous reservoirs in the Jianghan Plain area. This study aims to provide a scientific basis for the further exploration of hydrocarbons in the Jianghan Plain and reduce the risks by analyzing the key factors for hydrocarbon accumulation in the marine strata. Our findings show that in the Lower Palaeozoic hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the early period of the Early Yanshanian, and the hydrocarbon reservoir was destroyed in the middle-late period of the Early Yanshanian. In the Lower Triassic-Carboniferous hydrocarbon reservoir, oil/gas migration and accumulation chiefly occurred in the Early Yanshanian, and the hydrocarbon reservoir suffered destruction from the Late Yanshanian to the Early Himalayanian. The preservation conditions of the marine strata in the Jianghan Plain area have been improved since the Late Himalayanian. However, because all source beds have missed the oil/gas generation fastigium and lost the capacity to generate secondary hydrocarbon, no reaccumulation of hydrocarbons can be detected in the study area＇s marine strata. No industrially exploitable oil/gas reservoir has been discovered in the marine strata of Jianghan Plain area since exploration began in 1958. This study confirms that petroliferous reservoirs in the marine strata have been completely destroyed, and that poor preservation conditions are the primary factor leading to unsuccessful hydrocarbon exploration. It is safely concluded that hydrocarbon exploration in the marine strata of the study area is quite risky.
基金supported by State Key Laboratory of Palaeobiology and Stratigraphy (Nanjing Institute of Geology and Palaeontology,CAS) (Grant No.123115)the Fundamental Research Funds for the Central Universities"(Grant No.2010LKDZ01)
文摘The relationship between species diversity and ecosystem function is a hot topic in ecology and environics.This paper investi-gates the evolution of diversity of the late Middle Permian brachiopods community in Hechuan,Chongqing,China,and dis-cusses the relationship between species diversity and community productivity in terms of the geohistorical development.This paper shows that the species diversity is externalized by several indexes,and the relationship between diversity and productiv-ity is too complex to be described by a single assumption.The relationship between species diversity and community produc-tivity is restricted by environment and community evolution.When the community succeeds normally,the relationship be-tween species richness index,species diversity index,and species evenness index to productivity is in linear dependence rela-tion to each other,which is met with the third assumption.But,when the environment interference surpasses the bearing capa-bility of the community,not only the community succession will be terminated and be replaced by another one,but also the relationship between species richness index,species diversity index,and species evenness index to productivity is also in-versed to negative correlation by the interference from environment.Only the relationship between ecological dominance and productivity is in linear dependence relation to each other and approximately met with the third assumption.It is illustrated that the assumption that the productivity is in linear dependence relation with diversity should be established on the presupposition that the community succession is normal.
