Temperature logging curves at 8 boreholes and well-testing temperature data at 142 boreholes are used to determine geotemperature gradients in the Bohai Basin. The thermal conductivities of 86 rock samples are measure...Temperature logging curves at 8 boreholes and well-testing temperature data at 142 boreholes are used to determine geotemperature gradients in the Bohai Basin. The thermal conductivities of 86 rock samples are measured at laboratory and the effects of porosity and temperature are corrected to obtain conductivities in situ. Terrestrial heat flow densities at 76 wells are determined based on these data. The distribution of the heat flow indicates that the terrestrial heat flow in the Bohai Basin is relatively high with an average value of 65.8 mW/m2. This characteristic is caused by the tectonic evolution of the basin. During Cenozoic, the litho-sphere stretched intermittently and the crust thinned so that heat conducted from the mantle increased and formed thermal abnormity at depth beneath the basin.展开更多
According to stastistic of present geotemperatures at the depths of 1000,2000,3000 and 4000 m,respectively in the Xujiaweizi fault-depression of the north Songliao Basin,the result indicates that Xujiaweizi fault-depr...According to stastistic of present geotemperatures at the depths of 1000,2000,3000 and 4000 m,respectively in the Xujiaweizi fault-depression of the north Songliao Basin,the result indicates that Xujiaweizi fault-depression falls in the high geotemperature area,with the higher geothermal gradient in the depression layer than that in the fault-depression layer.The geothermal gradient decreases with the increasing of the depth.The thermal conductivity of rock greatly controls the geothermal gradient.The main factors constraining the current geotemperature include thermal configuration of the earth's crust, deep faults,distribution and abundance of radioelements.The high geotemperature is in favour of generation of deep gas.展开更多
Considering the high-temperature distribution along a tunnel in a high-altitude area,the effects of high geotemperature and high altitude on the pressure wave of trains running in long tunnels were investigated using ...Considering the high-temperature distribution along a tunnel in a high-altitude area,the effects of high geotemperature and high altitude on the pressure wave of trains running in long tunnels were investigated using a 3D,compressible,unsteady turbulence model.To reduce the simulation cost and reflect the pressure wave characteristics in long tunnels,a representative tunnel length was first determined for simulation.The simulation results indicated that compared to the condition of a normal ambient-temperature tunnel,when trains go through a high geotemperature tunnel,the distribution of the minimum pressure(Pmin)along the tunnel moves to the tunnel entrance.The pressure amplitudes on the tunnel and train decrease integrally,with maximum reductions of 7.9%in the maximum pressure(Pmax)and 44%in Pmin on the tunnel,and 4.6%in P_(max)and 12%in Pmin on the train.When trains meet in high geotemperature tunnels,the distributions of P_(max)and Pmin along the tunnel change.The pressure amplitudes decrease integrally,with maximum reductions of 13.8%in P_(max)and 36.9%in Pmin on the tunnel,and 7.1%in P_(max)and 15.6%in Pmin on the train.The pressure difference between the two sides of the train during the intersection decreases by 15.9%.As the altitude rises,when trains cross and meet in tunnels,the waveforms of pressures on the tunnel and train and the pressure difference between the two sides of the train remain unchanged,and the peaks decrease linearly.展开更多
The geothermal fields of coal-bearing strata have become a key topic in geological research into coal and coal bed methane(CBM).Based on temperature data from 135 boreholes that penetrate the Upper Permian coal-bearin...The geothermal fields of coal-bearing strata have become a key topic in geological research into coal and coal bed methane(CBM).Based on temperature data from 135 boreholes that penetrate the Upper Permian coal-bearing strata in the Bide-Santang basin,western Guizhou,the precisions of geothermal predictions made using a geothermal gradient model and a gray sequence GM(1,1)model are analyzed and compared.The results indicate that the gray sequence GM(1,1)model is more appropriate for the prediction of geothermal fields.The GM(1,1)model is used to predict the geothermal field at three levels with depths of 500,1000,and 1500 m,as well as within the No.6,No.16,and No.27 coal seams.The results indicate that the geotemperatures of the 500 m depth level are between 21.0 and 30.0°C,indicating no heat damage;the geotemperatures of the 1000 m depth level are between 29.4 and 44.7°C,indicating the first level of heat damage;and the geotemperatures of the 1500 m depth level are between35.6 and 63.4°C,indicating the second level of heat damage.The CBM contents are positively correlated with the geotemperatures of the coal seams.The target area for CBM development is identified.展开更多
基金This work was supported by the State Key Basic Research and Development Project of China (Grant No. G1999330402) the "95" Plan Research Project of China Ocean Petroleum Corporation (Grant No. 9605-3) the Research Fund for Doctoral Program of Higher E
文摘Temperature logging curves at 8 boreholes and well-testing temperature data at 142 boreholes are used to determine geotemperature gradients in the Bohai Basin. The thermal conductivities of 86 rock samples are measured at laboratory and the effects of porosity and temperature are corrected to obtain conductivities in situ. Terrestrial heat flow densities at 76 wells are determined based on these data. The distribution of the heat flow indicates that the terrestrial heat flow in the Bohai Basin is relatively high with an average value of 65.8 mW/m2. This characteristic is caused by the tectonic evolution of the basin. During Cenozoic, the litho-sphere stretched intermittently and the crust thinned so that heat conducted from the mantle increased and formed thermal abnormity at depth beneath the basin.
基金the Origin of Natural Gases and Mechanism of the Formation of LargeGas Fields in China for PetroChina(Grant No.07-01C-01-07)
文摘According to stastistic of present geotemperatures at the depths of 1000,2000,3000 and 4000 m,respectively in the Xujiaweizi fault-depression of the north Songliao Basin,the result indicates that Xujiaweizi fault-depression falls in the high geotemperature area,with the higher geothermal gradient in the depression layer than that in the fault-depression layer.The geothermal gradient decreases with the increasing of the depth.The thermal conductivity of rock greatly controls the geothermal gradient.The main factors constraining the current geotemperature include thermal configuration of the earth's crust, deep faults,distribution and abundance of radioelements.The high geotemperature is in favour of generation of deep gas.
基金supported by the National Key Research and Development Program of China(No.2020YFA0710902)the National Natural Science Foundation of China(Nos.12122211 and 11772275).
文摘Considering the high-temperature distribution along a tunnel in a high-altitude area,the effects of high geotemperature and high altitude on the pressure wave of trains running in long tunnels were investigated using a 3D,compressible,unsteady turbulence model.To reduce the simulation cost and reflect the pressure wave characteristics in long tunnels,a representative tunnel length was first determined for simulation.The simulation results indicated that compared to the condition of a normal ambient-temperature tunnel,when trains go through a high geotemperature tunnel,the distribution of the minimum pressure(Pmin)along the tunnel moves to the tunnel entrance.The pressure amplitudes on the tunnel and train decrease integrally,with maximum reductions of 7.9%in the maximum pressure(Pmax)and 44%in Pmin on the tunnel,and 4.6%in P_(max)and 12%in Pmin on the train.When trains meet in high geotemperature tunnels,the distributions of P_(max)and Pmin along the tunnel change.The pressure amplitudes decrease integrally,with maximum reductions of 13.8%in P_(max)and 36.9%in Pmin on the tunnel,and 7.1%in P_(max)and 15.6%in Pmin on the train.The pressure difference between the two sides of the train during the intersection decreases by 15.9%.As the altitude rises,when trains cross and meet in tunnels,the waveforms of pressures on the tunnel and train and the pressure difference between the two sides of the train remain unchanged,and the peaks decrease linearly.
基金This paper was jointly sponsored by a National Science and Technology Major Special Project of China(No.2016ZX05044)a Postdoctoral Science Foundation of China(No.2018M631181)a Key Project of the Natural Science Foundation of China(No.40730422).We thank all of the parties that contributed to this publication.
文摘The geothermal fields of coal-bearing strata have become a key topic in geological research into coal and coal bed methane(CBM).Based on temperature data from 135 boreholes that penetrate the Upper Permian coal-bearing strata in the Bide-Santang basin,western Guizhou,the precisions of geothermal predictions made using a geothermal gradient model and a gray sequence GM(1,1)model are analyzed and compared.The results indicate that the gray sequence GM(1,1)model is more appropriate for the prediction of geothermal fields.The GM(1,1)model is used to predict the geothermal field at three levels with depths of 500,1000,and 1500 m,as well as within the No.6,No.16,and No.27 coal seams.The results indicate that the geotemperatures of the 500 m depth level are between 21.0 and 30.0°C,indicating no heat damage;the geotemperatures of the 1000 m depth level are between 29.4 and 44.7°C,indicating the first level of heat damage;and the geotemperatures of the 1500 m depth level are between35.6 and 63.4°C,indicating the second level of heat damage.The CBM contents are positively correlated with the geotemperatures of the coal seams.The target area for CBM development is identified.
