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991.
深水盆地中大型侵入砂岩的地震识别及其成因机制探讨 总被引:3,自引:0,他引:3
侵入砂岩是深水盆地中常见的地质现象,由于本身具有高孔隙度、高渗透率的特点,对深水油气储集、运移和成藏均有重要的影响。综合国内外研究成果,探讨了深水盆地中大型侵入砂岩的地震特征和成因机制。研究表明侵入砂岩具有明显的强振幅地震反射,这些振幅异常一般呈V字形反射形态,沿着走向反映出一系列的特点,如阶梯性、分支性等,并伴有极性反转和高速度异常,在侵入砂岩下部的喉道出现上拉现象;关于侵入砂岩的成因,认为是未固结成岩阶段深水盆地中的异常超压砂体的向上侵位形成,大型的侵入砂岩及其伴生的断裂系统为流体运移提供渗流通道,深部水道或深水扇系统为侵入砂岩提供充足的物源。 相似文献
992.
993.
以某狭小场区超深基坑为例,详细的介绍了该项目的土方施工方案和各施工阶段相应的施工措施。探讨了利用常规运土车辆和挖掘机联合作业,通过多方面的施工措施完成了狭小场区基坑开挖的技术难题。通过妥善处理与支护施工交叉作业场地占用问题,分步分段进行开挖作业,优化布置场区内走向和坡度,合理安排好单步开挖深度及范围,采用分区块循环开挖的方法顺次推进,合理选择土方出运坡道的构筑材料,合理安排土方坡道改移作业时间,及时对坡道进行恢复,在最大限度的减少土方出运停歇时间的基础上,使场地内无坡道土方间歇期与支护施工各工序必要等待时间能够尽量协调一致。很好的保证了在狭小场地条件下按期完成既定土方施工计划,对今后同类项目的实施提供一定的帮助。 相似文献
994.
Hydrogen gas (H2) may be produced by the anoxic corrosion of steel components in underground structures, such as geological repositories for radioactive waste. In such environments, hydrogen was shown to serve as an electron donor for autotrophic bacteria. High gas overpressures are to be avoided in radioactive waste repositories and, thus, microbial consumption of H2 is generally viewed as beneficial. However, to fully consider this biological process in models of repository evolution over time, it is crucial to determine the in situ rates of microbial hydrogen oxidation and sulfate reduction. These rates were estimated through two distinct in situ experiments, using several measurement and calculation methods. Volumetric consumption rates were calculated to be between 1.13 and 1.93 μmol cm−3 day−1 for H2, and 0.14 and 0.20 μmol cm−3 day−1 for sulfate. Based on the stoichiometry of the reaction, there is an excess of H2 consumed, suggesting that it serves as an electron donor to reduce electron acceptors other than sulfate, and/or that some H2 is lost via diffusion. These rate estimates are critical to evaluate whether biological H2 consumption can negate H2 production in repositories, and to determine whether sulfate reduction can consume sulfate faster than it is replenished by diffusion, which could lead to methanogenic conditions. 相似文献
995.
996.
Study on the residence time of deep groundwater for high-level radioactive waste geological disposal 下载免费PDF全文
ZHOU Zhi-chao WANG Ju SU Rui GUO Yong-hai LI Jie-biao JI Rui-li ZHANG Ming DONG Jian-nan 《地下水科学与工程》2016,4(1):52-59
Residence time of deep groundwater is one of the most important parameters in safety and performance assessment for high-level radioactive waste geological disposal. In this study, we collected the deep groundwater samples of Jijicao in Gansu Beishan pre-selected region. The deep groundwater residence time at two depths estimated by Helium-4 accumulation method were 3.8 ka and 5.0 ka respectively upon measurement and calculation, which indicates that the deep groundwater is not derived from the deep crust circulation process. Hence, deep groundwater is featured with long residence time as well as slow circulation and update rate, and such features are conductive to the safe disposal of high-level radioactive waste. 相似文献
997.
The synoptic and dynamic aspects of heavy rainfall occurred on 5th May 2017 and caused flash flooding in arid and semi-arid central-northern Iran is analyzed by the Weather Research and Forecasting (WRF) model. This system synoptically is attributed to a surface low-pressure centered over southern Iran extended to the central parts, linking to a mid-tropospheric tilted-trough over western Iran, and advecting significant moisture from the Mediterranean Sea and the Red Sea to the studied area. The dynamical analysis revealed that the penetration of the upper-tropospheric potential vorticity streamer up to 300 hPa level was not related to such heavy rainfall. Contrarily, the low-level factors such as extensive moisture advection, mid-tropospheric diabatic processes such as the latent heat release, daytime deep convection, and topographical impact of Zagros Mountains were found as the key factors leading to this system. This study also examines 11 different convection schemes simulated by the WRF model and verified against rainfall observation. The forecast skills of the output simulations suggest the Grell-Devenyi scheme as the superior configuration in simulating observed precipitation of the event over the area. 相似文献
998.
利用1961—2019年江苏省67个站降水量和气候指数数据集等资料,选取大气环流、海温和积雪等先兆信号的不同组合作为预测因子方案,通过对比不同机器学习方法对江苏省夏季降水开展预测试验。结果表明,深度神经网络(Deep Neural Network,DNN)较传统统计方法和其他机器学习方法有一定优势,深度神经网络结合动态权重集合因子方案对江苏省夏季降水的预测技巧最高,其独立样本检验结果稳定,2015—2019年的平均PS评分为76.0,距平符号一致率为0.62,距平相关系数达0.35,尤其对江苏省中南部的预测技巧更高,具有业务应用价值。不同预测因子方案对比分析表明,大气环流因子在江苏省夏季降水预测中做主要贡献,而海温因子和积雪等其他因子也有正贡献,说明使用综合性预测因子以及集合方案有助于提升季节预测准确率。 相似文献
999.
The analyses focusing on formation mechanism of Nanzhangzhuang ground fissure in Hengshui City,China 下载免费PDF全文
The paper focuses on the formation of Nanzhangzhuang ground fissure through emphatically analysing factors including the intersection fault dislocation, the deep ground-water over-exploitation together with the landform and lithology features. Features of the ground fissure are explained in detail after describing the geological setting in the study area. The paper also provides dynamic mode of the ground fissure formation via force analysis of the soil body unit at ground fissures. Conclusions can be drawn that the stress state of soil bodies changed with the activities of two intersection faults, namely Hengshui fault and Hubei fault. In addition, the stress fields control the development of ground fissure. The deep groundwater in Hengshui area dropped considerably in recent years, to be precise, the water elevation of deep groundwater dropped from -26 m to -94 m by 2010 at the centre of groundwater funnel. The over-exploitation of deep groundwater in Hengshui area enlarged the ground fissures. The data concerning shallow borehole show that the vertical lithology mainly consists of silt, silty clay and silty sandy soil, which all belong to the middle-compressed soil. The lateral extension of the soil bodies occur with pumping and tectonic creep, and the clay layers on both sides of the cracks can stay upright. Thus the ground fissure came visible. 相似文献
1000.
Potential assessment of CO2 geological storage based on injection scenario simulation: A case study in eastern Junggar Basin 下载免费PDF全文
Ma Xin Wen Dong-guang Yang Guo-dong Li Xu-feng Diao Yu-jie Dong Hai-hai Cao Wei Yin Shu-guo Zhang Yan-mei 《地下水科学与工程》2021,9(4):279-291
Carbon Capture and Storage (CCS) is one of the effective means to deal with global warming, and saline aquifer storage is considered to be the most promising storage method. Junggar Basin, located in the northern part of Xinjiang and with a large distribution area of saline aquifer, is an effective carbon storage site. Based on well logging data and 2D seismic data, a 3D heterogeneous geological model of the Cretaceous Donggou Formation reservoir near D7 well was constructed, and dynamic simulations under two scenarios of single-well injection and multi-well injection were carried out to explore the storage potential and CO2 storage mechanism of deep saline aquifer with real geological conditions in this study. The results show that within 100 km2 of the saline aquifer of Donggou Formation in the vicinity of D7 well, the theoretical static CO2 storage is 71.967 × 106 tons (P50)① , and the maximum dynamic CO2 storage is 145.295 × 106 tons (Case2). The heterogeneity of saline aquifer has a great influence on the spatial distribution of CO2 in the reservoir. The multi-well injection scenario is conducive to the efficient utilization of reservoir space and safer for storage. Based on the results from theoretical static calculation and the dynamic simulation, the effective coefficient of CO2 storage in deep saline aquifer in the eastern part of Xinjiang is recommended to be 4.9%. This study can be applied to the engineering practice of CO2 sequestration in the deep saline aquifer in Xinjiang. 相似文献