渤中34地区东三段薄层滩坝砂形成主控因素及预测

黄河口凹陷渤中34地区东三段发育滨浅湖砂质滩坝,由于其储层薄、埋藏深,储层精细刻画难度大。以渤中34地区B油田为例,分析得到东三段薄层滩坝砂发育范围受控于古地形及其相关的水动力作用。在古地形的控制之下,不同的水动力背景下滩坝砂的发育可以进一步划分远岸坝、近岸坝、沿岸坝。其中古地形高部位发育宽缓的低洼区,在平均低潮线与高潮线之间,最有利于形成近岸坝是B油田滩坝发育的主要类型。以楔状模型为基础,正演出东三段储层振幅值的大小与砂体厚度存在正相关性,以此可以建立一种半定量计算模型。研究表明,基于滩坝主控因素约束下的地质模式与地震振幅属性共同预测对薄层滩坝砂体开发具有重要的指导意义。     

东太平洋海盆多金属结核生长历史的重建

依据多金属结核ＣＣＣ１４剖面上Ｍｎ、Ｆｅ、Ｎｉ、Ｃｕ的含量和有关的公式，本文计算该结核生长过程中瞬时生长速率和Ｍｎ、Ｆｅ、Ｎｉ、Ｃｕ的瞬时通量，并在结核中建立时间标尺，划分和对比结核生长阶段，重建结核ＣＣＣ１４８．７９３Ｍａ，Ｂ．Ｐ．以来的生长历史。研究结果表明，采用由铁、锰含量计算结核生长速率的公式，可详细了解结核生长过程，并能识别与提取强核中古海洋信息记录。     

基于地震波相似性的非局部均值滤波压制异常振幅噪音

非局部均值滤波是根据图像中各像素点间的相似性对图像进行去噪处理,但该方法不能有效压制图像中的异常振幅噪音。共偏移距道集（按炮点坐标排序的等炮检距道集）中同时刻的地震信号具有相似性高且分布范围集中的特征,因此可根据非局部均值滤波的权函数判断信号中的异常振幅噪音。基于上述理论,提出了基于地震波相似性的非局部均值滤波异常噪音压制方法,以有效地压制地震信号中的随机噪音与异常振幅噪音。该方法是在共偏移距道集中根据非局部均值滤波权函数来判断信号中的异常振幅噪音,并采用局部振幅统计估算对异常振幅噪音进行压制,从而达到去除地震信号中随机噪音和异常振幅噪音的目的。理论与实际地震数据试算结果表明,笔者所提出的方法可以有效地压制地震信号中的随机噪音和异常振幅噪音,可以让地震资料的信噪比得到进一步提高。     

Seistec Seismic Profiles: A Tool to Differentiate Gas Signatures

The presence of gas is a common feature in many seismic sections. However, the origin of the gas is often difficult to determine. Recently acquired very high resolution seismic profiles using an IKB Seistec boomer provide useful insight to the understanding of the gas origins in a range of environmental settings including sea lochs and coastal lagoons. The gas features are described both from a qualitative point of view through their acoustic facies, and quantitatively through the associated seismic signal (polarisation, amplitude). Acoustic facies include acoustic turbidity, gas “curtains” and “blankets” as well as “white fringes” and “black shadows”. All the features encountered have been related to specific gas nature generated by different sources (organic matter degradation in paleo-valley infillings, waste material effluent).     

后台阶下游床面冲刷过程数值模拟研究

以床面瞬时剪应力作为泥沙起动及输运的水动力机制,建立了结构物周围复杂流场下床面局部冲刷的数学模型。并应用大涡模拟方法对后台阶下游三维湍流流动进行数值模拟,得到台阶下游床面瞬时剪应力的分布规律。为了确定床面瞬时剪应力与泥沙上扬通量的关系,先应用数学模型对不同模型参数下,冲刷开始后5分钟时台阶下游床面形状进行试算。通过试算与实验结果的比较,确定床面瞬时剪应力与泥沙上扬通量关系中需要的模型参数。进一步对冲刷开始后30分钟内台阶下游床面演化规律进行模拟,模拟结果与实验结果相符合。     

华南全新世高海滩岩与海岸大震构造

笔者在世界上首次发现的华南海岸全新世高海滩岩中，又发现了海滩岩断代序列模式及其中蕴藏的重大科学信息。本文重点讨论高海滩岩与闽粤琼大震、大震构造与地震周期序列的关系，以及大震构造的定量标志。此外，继发现２５０年左右阶段的海岸升降年垂直活动速率后，又发现了５０年左右阶段的年活动速率。     

Exploiting Lateral Resolution of Near-Surface Seismic Refraction Methods

The 1D τ-p inversion algorithm is widely employed to generate starting models with most computer programs that implement refraction tomography. However, this algorithm emphasizes the vertical resolution of many layers, and as a result, it frequently fails to detect even large lateral variations in seismic velocities, such as the decreases that are indicative of shear zones. This study presents a case that demonstrates the failure of the 1D τ-p inversion algorithm to define or even detect a major shear zone that is 50 m or ten stations wide. Furthermore, the majority of refraction tomography programs parameterize the seismic velocities within each layer with vertical velocity gradients. By contrast, the 2D generalized reciprocal method (GRM) inversion algorithms emphasize the lateral resolution of individual layers. This study demonstrates the successful detection and definition of the 50-m wide shear zone with the GRM inversion algorithms. The existence of the shear zone is corroborated by a 2D analysis of the head wave amplitudes and by numerous closely spaced orthogonal seismic profiles carried out as part of a later 3D refraction investigation. Furthermore, a 1D analysis of the head wave amplitudes indicates that a reversal in the seismic velocities, rather than vertical velocity gradients, occurs in the weathered layers. While all seismic refraction operations should aim to provide as accurate depth estimates as is practical, the major conclusion reached in this study is that refraction Inversion algorithms that emphasize the lateral resolution of individual layers generate more useful results for geotechnical and environmental applications. The advantages of the Improved lateral resolution are obtained with 2D profiles in which the structural features can be recognized from the magnitudes of the variations in the seismic velocities. Furthermore, the spatial patterns obtained with 3D investigations facilitate the recognition of structural features that do not display any intrinsic variation or "signature" in seismic velocities.     

基于渐进谱的幅值和频率非平稳人造地震动拟合

在Priestley渐进谱和常用反应谱拟合技术基础上,提出一种拟合目标渐进谱生成幅值和频率非平稳地震动加速度时程的方法。由Nakayama方法获得目标渐进谱,定义[0,2π]的随机数作为初始相位。在迭代过程中考虑渐进谱和相位的影响,同时调整合成时程的渐进谱和相位,直到满足迭代的收敛要求。本文方法合成时程不仅保留目标渐进谱的时频非平稳特性,相位也具有与实际地震动相符合的时频非平稳性。时程的相关分析表明,输入不同初相位合成的时程在统计上互不相关。     

定向裂缝对地震波速度和振幅影响的比较—实验结果分析

利用垂直定向裂缝模型和MTS岩石物性测试系统，测试了不同材料和不同状态裂缝模型的地震特征响应。对特征响应进行分析和比较后发现，虽然波的传播速度，振幅，吸收衰减，主频均可用来检测裂缝的特征参数，但是裂缝变化对振幅的影响大于对速度的影响。因此，利用地震波的振幅、衰减等属性参数检测裂缝特征比利用速度参数更有效。     

常时微动测试在抗震设计上的应用

简要介绍了常时微动的基础知识、分类、研究现状及其在抗震设计工程中的应用。