大民屯凹陷高分辨地震资料处理技术研究

通过对大民屯凹陷地震资料的详细分析，针对洼陷部位信噪比高、主要目的层沙三、沙四段频率相对较低的特点，研究出一套高分辨率处理技术，主要包括子波处理技术及优势频带约束下的分频处理技术，能满足沙三、沙四段储层横向预测的需要，见到了较好的应用效果。     

Investigation of Crustal Thickness in Eastern Anatolia Using Gravity,Magnetic and Topographic Data

The tectonic regime of Eastern Anatolia is determined by the Arabia-Eurasia continent-continent collision. Several dynamic models have been proposed to characterize the collision zone and its geodynamic structure. In this study, change in crustal thickness has been investigated using gravity, magnetic and topographic data of the region. In the first stage, two-dimensional low-pass filter and upward analytical continuation techniques were applied to the Bouguer gravity data of the region to investigate the behavior of the regional gravity anomalies. Next the moving window power spectrum method was used, and changes in the probable structural depths from 38 to 52 km were determined. The changes in crustal thickness where free air gravity and magnetic data have inversely correlated and the type of the anomaly resources were investigated applying the Euler deconvolution method to Bouguer gravity data. The obtained depth values are consistent with the results obtained using the power spectrum method. It was determined that the types of anomaly resources are different in the west and east of the 40° E longitude. Finally, using the obtained findings from this study and seismic velocity models proposed for this region by previous studies, a probable two-dimensional crust model was constituted.     

Test of the Empirical Green's Function Deconvolution on Vrancea (Romania) Subcrustal Earthquakes

Vrancea is one of the few singular seismic regions of the world where intermediate-depth earthquakes are permanently generated (around 10 events/month with M _L > 3) within an extremely confined focal volume. This particularity and the relatively large number of short-period waveforms recorded by the Romanian local network provides us the opportunity to test the performance of the empirical Green's function technique in retrieving the source time function and source directivity of the Vrancea earthquakes. Three earthquakes that occurred on March 11, 1983 (M _L = 5.4), April 12, 1983 (M _L = 5.1) and August 7, 1984 (M _L = 5.1) in the lower part of the subducting lithosphere (h 150 km) were analyzed. A set of 28 adjacent events (3.0 < M _L < 4.4) which occurred between 1981 and 1997 were selected as corresponding empirical Green's functions. To test the confidence of the retrieved source time function, we compare the deconvolved pulses using Green's functions of different sizes and recorded simultaneously by short-period and broad-band instruments. Our tests show that the durations of the source time function is well-constrained and is not affected by the limited frequency range of the short-period instruments, or by the relative difference in the focal mechanism between the main event and Green's event. The apparent duration of the source time function outlines source directivity effects, and when these effects are sufficiently strong, they can identify the real fault plane. Relatively short source duration and correspondingly high stress drop values are in agreement with other previous results emphasizing a specific seismic regime in the lower part of the Vrancea subducting lithosphere.     

改进APEX算法在图像增强中的应用

APEX是一种基于快速傅立叶变换的直接盲解卷积算法,能够快速复原复杂纹理图像。该算法适用于平移不变且以2维放射对称Le’vy Stable概率密度函数(G类点扩散函数)作为卷积核的图像。论述了A-PEX算法的原理,并针对APEX在适应性和稳定性方面的不足提出了改进方法。实验表明,改进的APEX算法能够有效应用在多种真实模糊图像上,增强图像对比度和锐化图像细节,使图像的视觉效果得到明显改善。     

基于HMRF先验模型的HBE卫星遥感图像超分辨率重建

提出了一种在Bayes概率统计框架下的混合Bayes超分辨率重建算法，该算法采用Huber马尔可夫随机场（Huber Markov random field，HMRF）模型对理想图像进行先验建模，可以较好地突出重建图像的不连续边缘特征信息。实验结果表明，该算法克服了极大后验概率估计（maximum a posteriori，MAP）算法中的若干缺陷，取得了良好的重建结果，图像边缘特征清晰，纹理信息突出。     

预条件共轭梯度反褶积的改进及其应用

预条件共轭梯度反褶积方法是结合盲反褶积的实现,运用基于Krylov子空间上优化的预条件共轭梯度法,完成反射系数的反演.用该方法处理地震资料时可提高资料频率,展宽有效频率宽度.但由于地震数据对不同频带的信噪比有差异,若直接运用该反褶积处理常伴随分辨率提高的同时出现信噪比显著降低的现象.对于此,本文采取如下方法的改进措施：①在时间域上,当地震数据的振幅较大时,对应的反褶积数据的振幅取值与原地震数据的振幅相等;②在频率域上,当地震数据的频谱幅值大于一定阀值时,对应的反褶积数据的频谱取做原地震数据的频谱.由本文所给的数值算例可以看出,此两项改进方法可取得较好的实用效果.     

地震子波处理的二步法反褶积方法研究

针对玛湖斜坡区三块三维地震资料和赛汉塔拉凹陷二块三维地震资料连片处理中的特点,结合地质任务和处理目标要求,提出了地震数据连片处理中的地震子波处理的方法.该方法主要体现了两次反褶积,一次是采用地表一致性反褶积,将不同震源的频带拓宽到一个标准上;再一次采用相位校正反褶积,将不同震源的数据校正到相同相位上.为了保证提取的相位校正反褶积算子稳定,采用叠后地震道提取（主要考虑到叠后地震道信噪比高,算子稳定性强）,然后将该算子应用到叠前地震道,进行相位校正.     

克希霍夫叠前时间偏移技术在复杂构造带地震资料处理中的应用

在辽河盆地东部凹陷中部的A区块地下构造复杂,以往的资料虽然反应了该区的整体面貌,但断裂带的成像效果不是很好,为此,开展了叠前时间偏移处理技术研究.详细介绍了保福克希霍夫叠前时间偏移的原理和数据的预处理,讨论了主要的偏移参数的测试和选取方法,通过Deregowski循环法和百分比偏移扫描速度建立和优化速度模型.处理结果表明,该区三维叠前偏移剖面较常规三维叠后偏移剖面有明显改善.     

Analysis of the Frequency Domain Water-level Deconvolution Method Based on Reservoir Airgun Source Data

Based on the 2016 airgun experimental data of the Fujian Nanyi reservoir, we adopted the frequency domain water-level deconvolution method and cross-correlation time delay detection technique to study the influence of level scaling factor and the background noise level of the station on deconvolution calculation results, and analyze the effect of deconvolution on eliminating the influence of the source caused by different air-gun pressures. The results show that:(1) When the level scaling factor is smaller, the signal to noise ratio of the waveform after the deconvolution is smaller, and when the level scaling factor is over smaller, the identification error of travel time is greater. (2) When the SNR of the station record is higher, the recognition accuracy of travel time is higher, the influence of SNR on the reference station record is far greater than the far station, when the SNR of the far station record is more than 10, the error of travel time is within 6ms, but when the SNR of the reference station record is 30, the travel time error may reach to 20ms. (3) When the airgun source difference is big, the frequency domain water-level deconvolution method has better effect on eliminating the source influence, but the method error may be introduced when the source difference is small.