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21.
准噶尔盆地腹部侏罗系超压特征和测井响应以及成因 总被引：3，自引：1，他引：2
准噶尔盆地腹部地区深层钻井揭示侏罗系发育异常高压系统.根据26口井的67个钻杆测试(DST) 和电缆测试(MDT) 数据, 实测砂岩异常高压揭示深度约在4470~6160m, 剩余压力约为11~57MPa, 压力系数为1.24~2.07, 砂岩段超压实测值主要分布在侏罗系, 少数出现在白垩系底部与侏罗系邻近地层, 1个超压实测值位于下三叠统, 实测超压砂岩样品的孔隙度和渗透率范围分别为3.20%~16.00%和0.02×10-3~14.40×10-3μm2;根据钻井、测井和测试资料的综合解释, 埋深在4430~6650m的深部侏罗系流体超压带, 钻井泥浆密度明显增加, 泥页岩和砂岩共同具有相对于正常趋势的异常高声波时差和低视电阻率测井响应特征; 超压系统顶界埋深可能不浅于4400m (地温约104℃), 有些钻井超压顶界可深达约6000m (地温约140℃), 且超压带顶界深度随侏罗系埋深的增加而增大; 钻井揭示的侏罗系超压带烃源岩镜质体反射率(Ro, %) 约为0.7%~1.3%, 超压带分布深度受控于侏罗系成熟烃源岩层的埋深且两者深度分布的变化具有相关性; 研究认为腹部地区已被充分压实的侏罗系异常高压成因主要与其含煤岩系干酪根热演化及油气共生有关, 即生烃增压; 物理模拟实验表明, 由于高孔隙流体压力可导致岩石骨架颗粒间有效应力的减小, 从而直接引起通过岩石的声波速度降低, 即出现高声波时差响应; 在超压地层温度条件下, 高压液态水的电离常数可能明显增加, 从而减小地层电阻率, 进一步开展此种现象的相关探索性研究可望对超压带低电阻率异常的原因给出新的解释. 相似文献
22.
WANG Heng-zhi YU Yan-xiang HE Bin PENG Xiao-bo ZHAN Xiao-yan ZHU Sheng-chu 《地震地质》2018,40(6):1349-1361
An M4.9 earthquake occurred at the junction of Gaoyou and Baoying on July 20, 2012. In this paper, 43 sets of strong motion records of the main shock are analyzed. With these data, we analyzed the characteristics of the peak ground motion value, attenuation relation, duration and acceleration response spectrum. We draw the peak acceleration contour map of the region near the epicenter. The contour line is smooth and the trend of long axis is northwest-southeast. Distribution of peak acceleration of the observed records is basically consistent with the real intensity distribution. Compared with the predicted result based on the seismic attenuation relation proposed by Yu Yanxiang and Wang Suyunon for eastern China and the Fifth-generation ground motion zonation map, the horizontal PGA and PGV of Gaoyou-Baoying earthquake are higher than the predicted results that are based on the model of Fifth-generation ground motion zonation map, while the PGV is similar with the predicted results which are based on Yu Yanxiang and Wang Suyun's model. We regressively analyzed the spatial-temporal change curves of the two types of relative ground motion durations. Compared with the predicted results proposed by Bommer et al. (2009) based on the NGA strong motion records, the durations of all the three components of this earthquake are higher. 10 typical recordings' acceleration response spectra with 5% damping are calculated, their peak periods are around 0.1~0.3s. The acceleration response spectrum of the station 32BYT, which has the largest amplitude, is considerably larger than the Chinese code design spectra, while it becomes notably smaller when the period is larger than 0.4s. Compared with the horizontal bedrock acceleration response spectrum predicted by the attenuation relationship for the eastern part of China, the observed response spectrum shape is similar with the predicted ones, while almost all the observed response spectrum values (except station 32YCT)are smaller than the predicted bedrock acceleration response spectrum. These phenomena suggest that this earthquake has a weak impact on the seismic fortification standards in this area. Using H/V single-station spectral ratio method, amplitude and site amplification effect of the two typical stations are calculated, and the results show the H/V values are obviously larger than that of ground microtremor. This suggests that the site of the station has obvious amplification effect on ground motion. 相似文献
23.
为解决合成孔径雷达(SAR)图像存在大量混合像元的问题,针对传统ICA不能有效解决混合像元分解这一缺陷,提出一种新的独立成分分析算法--有监督学习ICA算法(SL-ICA).其目标函数是在原ICA负熵目标函数基础上增加监督学习的约束条件项,进而在同一目标函数内实现负熵和约束条件的统一,在最大化负熵的同时也最小化了约束条件的误差,此外,采用一种新的双梯度下降法优化迭代,提高计算速度.并以人工模拟SAR图像和北京地区ENVISAT-ASAR作为数据源进行实验,实验结果明显优于主成分分析方法(PCA)的分解结果. 相似文献