The geothermal history and the tectonic subsidence history of the Huaibei-Huainan coalfields were reconstructed by using the vitrinite reflectance data, and their correlative restriction on coalbed gas generation of H...The geothermal history and the tectonic subsidence history of the Huaibei-Huainan coalfields were reconstructed by using the vitrinite reflectance data, and their correlative restriction on coalbed gas generation of Huaibei-Huainan coalfields and Qinshui coal basin was discussed. The burial, thermal, and maturity histories of are similar between Huaibei coalfield and Huainan coalfield, obviously different from those of Qinshui coal basin. Based on the tectono-thermal evolution characters of Huaibei-Huainan coalfields and Qinshui basin, the process of coalbed gas generation can be divided into three stages： （1） Dur- ing Early Mesozoic, both in Huaibei-Huainan and Qinshui, the buried depth of Permian coal seams increased rapidly, which resulted in strong metamorphism and high burial temperature of coal seams. At this stage, the coal rank was mainly fat coal, and locally reached coking coal. These created an environment favoring the generation of thermogenic gas. （2） From Late Ju- rassic to Cretaceous, in the areas of Huaibei-Hualnan, the strata suffered from erosion and the crust became thinning, and the Permian coal-bearing strata were uplifted to surface. At this stage, the thermogenic gas mostly escaped. Conversely, in Qinshui basin, the cover strata of coal seams kept intact during this stage, and the thermogenic gas were mostly preserved. Furthermore, with the interaction of magmatism, the burial temperature of coal seams reached higher peak value, and it was suitable for the secondary generation of thermogenic gas. （3） From Paleogene onward, in area of Huainan-Huaibei, the maturity of coal and burial temperature were propitious to the generation of secondary biogenic gases. However, in Qinshui basin, the maturity of coal went against genesis of second biogenic gas or thermogenic gas. By comparison, Huaibei-Huainan coalfields are dominated by thermogenic gas with a significant biogenic gas and hydrodynamic overprint, whereas Qinshui basin is dominated mainly by thermogenic gas.展开更多
The Sichuan Basin, located in the western margin of Yangtze Plate, is one of the important oil-gas-bearing basins in China. During the Early Permian-Middle Triassic, the Sichuan Basin experienced regional lithospheric...The Sichuan Basin, located in the western margin of Yangtze Plate, is one of the important oil-gas-bearing basins in China. During the Early Permian-Middle Triassic, the Sichuan Basin experienced regional lithospheric extension and Emeishan basalt activities, both of which influenced the basin development and thermal evolution. Here we simulated the thermal effects of lithospheric extension and the Emeishan mantle plume based on different geodynamical models. Modeling results indicated that the lithospheric temperature together with the basement heat flow was generally increasing with time due to extension. As the stretching factor was relatively small, the thinning of lithosphere, and consequently the thermal disturbance, was not great. The lithospheric extension yielded about 20% increase of the basement heat flow, with maximum value of 60?62 mW m?2 in the Early Triassic. Mantle plume model shows that the thermal evolution of the inner zone above the plume head was influenced greatly by plume activity. But the outer zone and its outside area where the Sichuan Basin is located were affected only slightly. The basalts that had erupted in the southwestern basin might disturb the basin temperature significantly, although shortly and locally. Generally, the thermal history of the Sichuan basin during the Early Permian-Middle Triassic was controlled by the lithospheric extension, but locally it superimposed thermal effects of basalt activities in its southwestern area.展开更多
Basin modeling has become an important tool for analyzing sedimentary basins. The North Subbasin of the South Yellow Sea Basin is filled with thick Meso-Cenozoic terrigenous deposits during the rift evolution stage. T...Basin modeling has become an important tool for analyzing sedimentary basins. The North Subbasin of the South Yellow Sea Basin is filled with thick Meso-Cenozoic terrigenous deposits during the rift evolution stage. The accumulation of data and achievements of geological investigations in recent years have provided the preconditions for basin modeling. The necessary parameters and geological elements for simulations are collated and summarized. Modeling of tectono-thermal evolution is performed and the related trend in heat flow is reconstructed and calibrated. The heat flow value commences from an average level of 61 m W/m2during MiddleLate Jurassic, rises to about 80 m W/m2from circa 145 Ma to circa 74 Ma, and then undergoes a gradual decline to65 m W/m2until the end of Oligocene.Three evolutionary phases, namely, the initial rifting phase, syn-rifting phase, and post-rifting phase, have been identified. The modeling results show that the North Subbasin generally enters into a stage of strong rifting during Cretaceous and undergoes rapid subsidence until the Late Cretaceous,then follows by a stage of moderate rifting during the Paleogene. The input and general workflow involved in 3-D modeling are introduced. Reconstruction of the petroleum system in the North Subbasin reveals that the threshold depth of hydrocarbon generation is located near the top of the Paleogene Funing formation, and the underlying Jurassic and Cretaceous source rocks have reached or exceeded peak oil generation and have almost completed the generation and expulsion of hydrocarbons. The main generation and expulsion in the Jurassic source rocks take place during the syn-rifting and post-rifting phases, whereas the peak generation and expulsion in the Cretaceous and Paleogene source rocks take place during the post-rifting phase. Although the study area is still a relatively less explored sedimentary basin, the results of modeling can provide valuable information for exploration. A preliminary discussion of the main uncertainty factors is a展开更多
Based on the observed data, the average value of surface heatflow in the Yinggehai Basin is calculated and it turns out to be 84.1 mW/m2. The thermal evolution of the basin since the Cenozoic era has been attempted by...Based on the observed data, the average value of surface heatflow in the Yinggehai Basin is calculated and it turns out to be 84.1 mW/m2. The thermal evolution of the basin since the Cenozoic era has been attempted by tectono-thermal modeling. Three-phase extension made the basin become hotter and hotter, reaching its climax in paleo-temperature history since 5.2 Ma. And nowadays, the basin is in the heat flow decreasing period. During the Cenozoic era, the basement heat flow remained at 50-70 mW/m2 all the time. This is related to the degree of each extension phase, stretching rate mode and also the limited basin scale. Modeling results also show that, the surface heat flow is controlled mainly by the basement heat flow, and less than 20% comes from radiogenic heat production in the sediments of the basin.展开更多
Ⅰ. IMPLICATIONS OF THE INTEGRATED STUDY OF THE TECTONO-THERMAL EVOLUTIONRef. [1] reported 13 heat flow values along the profile from Yadong to the Qaidam Basin for the first time. After further systematic analysis an...Ⅰ. IMPLICATIONS OF THE INTEGRATED STUDY OF THE TECTONO-THERMAL EVOLUTIONRef. [1] reported 13 heat flow values along the profile from Yadong to the Qaidam Basin for the first time. After further systematic analysis and verification, these data together with the latitudes and longitudes of the heat flow sites, depth interval of linear sections, tem-展开更多
基金supported by National Natural Science Foundation of China (Grant Nos. 41030422, 40772135, 40972131, 40940014)National Basic Research Program of China (Grant No. 2009CB219601)
文摘The geothermal history and the tectonic subsidence history of the Huaibei-Huainan coalfields were reconstructed by using the vitrinite reflectance data, and their correlative restriction on coalbed gas generation of Huaibei-Huainan coalfields and Qinshui coal basin was discussed. The burial, thermal, and maturity histories of are similar between Huaibei coalfield and Huainan coalfield, obviously different from those of Qinshui coal basin. Based on the tectono-thermal evolution characters of Huaibei-Huainan coalfields and Qinshui basin, the process of coalbed gas generation can be divided into three stages： （1） Dur- ing Early Mesozoic, both in Huaibei-Huainan and Qinshui, the buried depth of Permian coal seams increased rapidly, which resulted in strong metamorphism and high burial temperature of coal seams. At this stage, the coal rank was mainly fat coal, and locally reached coking coal. These created an environment favoring the generation of thermogenic gas. （2） From Late Ju- rassic to Cretaceous, in the areas of Huaibei-Hualnan, the strata suffered from erosion and the crust became thinning, and the Permian coal-bearing strata were uplifted to surface. At this stage, the thermogenic gas mostly escaped. Conversely, in Qinshui basin, the cover strata of coal seams kept intact during this stage, and the thermogenic gas were mostly preserved. Furthermore, with the interaction of magmatism, the burial temperature of coal seams reached higher peak value, and it was suitable for the secondary generation of thermogenic gas. （3） From Paleogene onward, in area of Huainan-Huaibei, the maturity of coal and burial temperature were propitious to the generation of secondary biogenic gases. However, in Qinshui basin, the maturity of coal went against genesis of second biogenic gas or thermogenic gas. By comparison, Huaibei-Huainan coalfields are dominated by thermogenic gas with a significant biogenic gas and hydrodynamic overprint, whereas Qinshui basin is dominated mainly by thermogenic gas.
基金supported by Sinopec Marine Forward-looking Projects (Grant No. YPH08101)
文摘The Sichuan Basin, located in the western margin of Yangtze Plate, is one of the important oil-gas-bearing basins in China. During the Early Permian-Middle Triassic, the Sichuan Basin experienced regional lithospheric extension and Emeishan basalt activities, both of which influenced the basin development and thermal evolution. Here we simulated the thermal effects of lithospheric extension and the Emeishan mantle plume based on different geodynamical models. Modeling results indicated that the lithospheric temperature together with the basement heat flow was generally increasing with time due to extension. As the stretching factor was relatively small, the thinning of lithosphere, and consequently the thermal disturbance, was not great. The lithospheric extension yielded about 20% increase of the basement heat flow, with maximum value of 60?62 mW m?2 in the Early Triassic. Mantle plume model shows that the thermal evolution of the inner zone above the plume head was influenced greatly by plume activity. But the outer zone and its outside area where the Sichuan Basin is located were affected only slightly. The basalts that had erupted in the southwestern basin might disturb the basin temperature significantly, although shortly and locally. Generally, the thermal history of the Sichuan basin during the Early Permian-Middle Triassic was controlled by the lithospheric extension, but locally it superimposed thermal effects of basalt activities in its southwestern area.
基金The National Special Project for Marine Geology of China under contract No.DD20160147the National Basic Research Program(973 Program) of China under contract No.2013CB429701the National Natural Science Foundation of China under contract No.41210005
文摘Basin modeling has become an important tool for analyzing sedimentary basins. The North Subbasin of the South Yellow Sea Basin is filled with thick Meso-Cenozoic terrigenous deposits during the rift evolution stage. The accumulation of data and achievements of geological investigations in recent years have provided the preconditions for basin modeling. The necessary parameters and geological elements for simulations are collated and summarized. Modeling of tectono-thermal evolution is performed and the related trend in heat flow is reconstructed and calibrated. The heat flow value commences from an average level of 61 m W/m2during MiddleLate Jurassic, rises to about 80 m W/m2from circa 145 Ma to circa 74 Ma, and then undergoes a gradual decline to65 m W/m2until the end of Oligocene.Three evolutionary phases, namely, the initial rifting phase, syn-rifting phase, and post-rifting phase, have been identified. The modeling results show that the North Subbasin generally enters into a stage of strong rifting during Cretaceous and undergoes rapid subsidence until the Late Cretaceous,then follows by a stage of moderate rifting during the Paleogene. The input and general workflow involved in 3-D modeling are introduced. Reconstruction of the petroleum system in the North Subbasin reveals that the threshold depth of hydrocarbon generation is located near the top of the Paleogene Funing formation, and the underlying Jurassic and Cretaceous source rocks have reached or exceeded peak oil generation and have almost completed the generation and expulsion of hydrocarbons. The main generation and expulsion in the Jurassic source rocks take place during the syn-rifting and post-rifting phases, whereas the peak generation and expulsion in the Cretaceous and Paleogene source rocks take place during the post-rifting phase. Although the study area is still a relatively less explored sedimentary basin, the results of modeling can provide valuable information for exploration. A preliminary discussion of the main uncertainty factors is a
基金the National Natural Science Foundation of China (Grant Nos. 49732005 49804004) and Key-Project (KZ951-A1-401) of Chinese Academy of Sciences.
文摘Based on the observed data, the average value of surface heatflow in the Yinggehai Basin is calculated and it turns out to be 84.1 mW/m2. The thermal evolution of the basin since the Cenozoic era has been attempted by tectono-thermal modeling. Three-phase extension made the basin become hotter and hotter, reaching its climax in paleo-temperature history since 5.2 Ma. And nowadays, the basin is in the heat flow decreasing period. During the Cenozoic era, the basement heat flow remained at 50-70 mW/m2 all the time. This is related to the degree of each extension phase, stretching rate mode and also the limited basin scale. Modeling results also show that, the surface heat flow is controlled mainly by the basement heat flow, and less than 20% comes from radiogenic heat production in the sediments of the basin.
基金Project supported by the National Natural Science Foundation of China.
文摘Ⅰ. IMPLICATIONS OF THE INTEGRATED STUDY OF THE TECTONO-THERMAL EVOLUTIONRef. [1] reported 13 heat flow values along the profile from Yadong to the Qaidam Basin for the first time. After further systematic analysis and verification, these data together with the latitudes and longitudes of the heat flow sites, depth interval of linear sections, tem-
